Hey Everyone 👋
Mateus G. Rocha
DDS | MSc | PhD | P. Cert.
I am a Clinical Associate Professor and Director of the Center for Dental Biomaterials at the University of Florida College of Dentistry. My work focuses on developing advanced dental materials and, perhaps more uniquely, applying artificial intelligence and machine learning to revolutionize how we design and test these materials. My research spans from creating novel photoinitiator systems and bulk-fill composites to using AI for predicting material performance and optimizing testing protocols. I’m working on using predictive modeling, large language models, and neural networks to enhance the properties of dental materials and streamline their development process.
You might say I wear two hats – I’m a dentist who codes and a programmer who practices dentistry. I often joke that I’m equally at home discussing Python scripts or dental composites, and I can debug both computer code and tooth decay with the same enthusiasm!
I’m also passionate about teaching and mentoring the next generation of dental professionals, helping them understand how to harness the power of technology in their career goals.
Education
Doctor of Dental Surgery
2010 – 2013
Federal University of Rio de Janeiro
MSc in Dental Materials
2014 – 2016
State University of Campinas
PhD in Dental Materials
2016 – 2019
State University of Campinas
P. Cert. Machine Learning
2022
University of California, Berkeley
Cert. AI/ML for Big Data and LLM
2024
Massachusetts Institute of Technology
Experience
Director, Center for Dental Biomaterials
July 2021 – Present
University of Florida College of Dentistry
Clinical Associate Professor
July 2024 – present
University of Florida College of Dentistry
Clinical Assistant Professor
August 2019 – June 2024
University of Florida College of Dentistry
Research Projects and Innovations
Discover how we’re pushing the boundaries of research and education in dental materials
Materials Informatics
Machine Learning ⬌ Polymer Chemistry
We’re leveraging cutting-edge materials informatics techniques to revolutionize the way we discover and develop dental polymers. By combining vast materials databases with advanced machine learning algorithms, we’re able to:
– Predict the properties of potential materials before physical synthesis
– Identify promising polymer compositions for specific dental applications
– Optimize material characteristics such as strength, wear resistance, and aesthetics
– Enhance biocompatibility and reduce the risk of allergic reactions
Accelerated and Fatigue Testing
Materials Science and Engineering
Our innovative approach focuses on the development and optimization of accelerated aging and fatigue testing methodologies of dental biomaterials. By subjecting these materials to carefully designed and highly aggressive conditions, we can:
– Simulate years of clinical use within a condensed timeframe
– Identify potential failure modes and degradation mechanisms
– Assess the long-term performance and durability of dental biomaterials
– Evaluate the effects of oral environment factors on material properties
– Optimize material composition and structure for enhanced clinical performance
Full-Stack AI-Driven Solutions
Product Design ⬌ Artificial Intelligence
Our innovative approach focuses on the development and optimization of full-stack AI-driven solutions that leverage large language models, neural networks, and graph knowledge to transform education and research. We create AI models that are trained for personalized tasks and topics, enabling educators, researchers, and students to access tailored support and resources. By harnessing these advanced technologies, we can:
– Provide personalized learning experiences and adaptive support for students
– Empower educators with tools for efficient teaching and insightful analytics
– Assist researchers in conducting comprehensive literature reviews and knowledge synthesis
– Enable seamless collaboration and knowledge sharing among educators and researchers
Publications
2024 |
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43. | Pereira R P, de Oliveira D C R S, Rocha M G, Roulet J, Geraldeli S, Sinhoreti M A C: Effect of butylated hydroxytoluene (BHT) concentrations on polymerization shrinkage stress and other physicochemical properties of experimental resin composites. In: Journal of the Mechanical Behavior of Biomedical Materials, 2024, ISSN: 1751-6161. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{Pereira2024, The present study examined different concentrations of the butylated hydroxytoluene (BHT) inhibitor on the kinetics of conversion, polymerization shrinkage stress, and other correlated physicochemical properties of experimental resin composites (ERC). A model composite was formulated with 75 wt% filler containing 0.5 wt% camphorquinone and 1 wt% amine with BHT concentrations of 0.01 wt% (BHT-0.01); 0.1 wt% (BHT-0.1); 0.25 wt% (BHT-0.25); 0.5 wt% (BHT-0.5); 1 wt% (BHT-1), and control (no BHT). They were tested on polymerization shrinkage stress (PSS; n = 5), degree of conversion (DC; n = 3), maximum polymerization rate (RpMAX; n = 5), water sorption (Wsp; n = 0), and solubility (Wsl; n = 10), flexural strength (FS; n = 10), flexural modulus (FM; n = 10), Knoop microhardness (KH; n = 10), and microhardness reduction (HR; n = 10). Data concerning these tests were submitted to one-way ANOVA and Tukey's test (α = 0.05; β = 0.2). BHT-0.25, BHT-0.5, and BHT-1 showed a gradually significant decrease in PSS (p = 0.037); however, BHT-1 demonstrated a decrease in the physicochemical properties tested. Thus, within the limitations of this study, it was possible to conclude that BHT concentrations between 0.25 and 0.5 wt% are optimal for reducing shrinkage stress without affecting other physicochemical properties of ERCs. | ||
42. | Sartori N, Sanchez S A, Oliveira D, Hosney S, Zoidis P, Martin W, Gonzaga L, Rocha M G: Flexural properties and fatigue limit of 3D-printed and milled resin-based materials. In: J Prosthodont, vol. n/a, no. n/a, 2024. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN6946, PURPOSE: The purpose of this study was to evaluate the flexural strength (FS), flexural modulus (FM), and fatigue limit (FL) of 3D-printed resin-based polymers and composites and compare them to 3D-printed composites. MATERIALS AND METHODS: A bar-shaped specimen (25 x 2 x 2 mm) was CAD designed according to ISO 4049:2019, and 60 duplicates of the 3D model were nested at a 45-degree angle with the printing platform and 3D-printed with three materials: denture teeth resin (Denture Teeth, Formlabs), temporary crown and bridge resin (Temporary CB, Formlabs), and composite (Flexcera Smile Ultra+, Desktop Health). The 3D model was also imported into a dental CAM software, duplicated 60 times, nested, and milled from a 3D-milled composite puck (Ivotion Denture Teeth, Ivoclar). All specimens were post-processed following the manufacturer's recommendation. The specimens were then subjected to a three-point bending test until failure using a Universal Testing Machine at a crosshead speed of 0.75 mm/min, and FS and FM were calculated. The remaining thirty specimens were tested for Fatigue Limit using the staircase approach starting at 50% FS maximum up to 1.2 M cycles at 10 Hz. The data were analyzed using one-way ANOVA and the Weibull distribution (alpha = 0.05). RESULTS: The results showed that Ivotion and Flexcera had higher FS (110.3 +/- 7.1 MPa and 107.6 +/- 6.4 MPa, respectively) and FM (3.3 +/- 0.1 GPa and 3.0 +/- 0.2 GPa, respectively) compared to the 3D-printed Denture Teeth (FS = 66.4 +/- 18.5 MPa and FM = 1.8 +/- 0.1 GPa) and Temporary CB (FS = 79.6 +/- 12.1 MPa and FM = 2.7 +/- 0.4 GPa). Weibull analysis showed that the Ivotion and Flexcera had a more uniform and narrower spatial distribution of defects (m: 27.98 and 29.19) than the printed materials, which had m values of 8.17 and 4.11 for Temporary CB and Denture Teeth, respectively. Although no differences were found in the static properties (FS and FM) between Ivotion and Flexcera, Ivotion presented a higher endurance limit than Flexcera (51.43 vs. 40.95 MPa). The Temporary CB presented 21.08 MPa and Denture Teeth presented 17.80 MPa of endurance limit. CONCLUSIONS: 3D-milled (Ivotion Denture Teeth) and 3D-printed (Flexcera Smile Ultra+) composites outperformed 3D-printed resins (Formlabs Denture Teeth and Temporary Crown & Bridge) in terms of flexural properties and fatigue resistance. 3D-milled (Ivotion) and 3D-printed (Flexcera) composites exhibited similar flexural properties, but 3D-milled composites showed a 25% higher fatigue endurance limit, suggesting improved clinical longevity. | ||
41. | Munhoz V, Rocha M, Correr A, Sinhoreti M, Geraldeli S, Oliveira D: The role of protective liners and glass ionomer in managing pulp temperature during light curing. In: Journal of Clinical and Experimental Dentistry, vol. 16, no. 6, pp. e749-e754, 2024. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{Munhoz2024, Background: This study evaluates the thermal insulation properties of protective liners and glass ionomer cement during light-curing procedures. Material and Methods: Human third molars underwent Class I preparations with dimensions 5 mm long × 4 mm wide × 4 mm deep in a standardized manner, ensuring a consistent ±0.5 mm dentin thickness at the pulpal floor. The teeth were attached to a customized oral cavity chamber simulator with a circulating bath at a standardized temperature of 34.2 ± 1°C. Temperature variations at the pulpal floor were captured in real-time using an infrared thermal camera (FLIR ONE Pro, FLIR Systems). The materials evaluated were Dycal (Dentsply), TheraCal LC (Bisco), Activa (Pulpdent), and Fuji II LC (GC). All light-activation procedures were performed with the same light-curing unit (Valo Grand, Ultradent) in standard mode, 1000 mW/cm², and exposure times followed manufacturer instructions. A power analysis was conducted to determine the sample size, considering a minimal power of 0.8, with α=0.05. Statistical analyses were performed using ANOVA and Tukey’s test for multiple comparisons. Results: The temperature at the pulpal floor increased above the 5.5 ºC safety threshold difference for the clinical scenarios tested. None of the materials provided proper thermal insulation for light-curing procedures (p = 0.25). The higher the number of light-cured steps, the longer the pulp remained above the 5.5 ºC temperature threshold. Conclusions: The materials tested provided improper thermal insulation (Δ > 5.5 ºC). Thus, prolonged or multiple light-curing exposures can be harmful to the pulp tissues. For indirect pulpal capping procedures, self-cured materials or a reduced number of steps requiring light curing should be adopted to reduce the amount of time the pulp remains above the 5.5 ºC safety temperature threshold. | ||
40. | Machado N, Rocha M G, Oliveira D, Reardon K G, Martins E, Lawson N C: Compressive modulus, translucency, and irradiance transmittance of clear PVS materials used for resin injection molding technique. In: J Esthet Restor Dent, vol. n/a, no. n/a, 2024. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN6948, OBJECTIVES: To evaluate the compressive modulus, translucency, and light curing irradiance transmittance of four clear polyvinyl siloxane (PVS) materials used for the injection molding technique at varying thicknesses, and to assess the correlation between color parameters and irradiance transmittance. MATERIALS AND METHODS: Four clear PVS materials (Exaclear, Clear Bite Matrix, Affinity Crystal, and Memosil 2) were used in this study. Compressive modulus was measured by compressing cylindrical PVS specimens (n = 9; d = 10 mm; t = 6 mm) up to 30% strain using a universal testing machine. For the translucency analysis and irradiance transmittance, specimens (n = 5) were fabricated with five different thicknesses (d = 12 mm and t = 2, 4, 6, 8 and 10 mm). The L*, a, *b* values of specimens were obtained using a CIELab spectrophotometer (CMD-700, Konica Minolta) with calibrated white and black tiles; the translucency parameter was calculated. The same specimens were placed onto a spectrophotometer (MARC Light Collector) to measure irradiance transmitted through the specimens from a light curing unit (Valo Corded, Ultradent). Data were analyzed using analysis of variance (ANOVA) with Tukey post hoc test and the correlation between translucency and irradiance transmittance of materials for each thickness was evaluated using Pearson's correlation. RESULTS: Compressive modulus differences in PVS materials were significant (one-way ANOVA: df = 3 | ||
39. | Kouveliotis G, Karoussis I, Papamanoli E, Tasopoulos T, Kourtis S, Rocha M, Oliveira D, Hosney S, Zoidis P: Customizing implant emergence profile and provisional prostheses. Combination of the digital and the analog protocol. A Case Report. In: Journal of Clinical and Experimental Dentistry, vol. 16, no. 6, pp. e789-e793, 2024. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN13718, The emergence profile in implant restoration has an important contribution to the final esthetic result. Moreover, a properly shaped emergence profile enables well-performed dental hygiene and protects the implant-restoration complex from peri-implant infections. This report describes a clinical case that combines digital workflow and designing with a custom implant healing abutment system (Cervico). This system is utilized to customize the provisional restoration’s emergence profile with the conventional processing along with the digitally designed and milled provisional restoration to deliver an interim prosthesis after implant placement. © Medicina Oral S. L. C.I.F. B 96689336 - eISSN: 1989–5488 eMail: jced@jced.es | ||
2023 |
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38. | Sinhoreti M A C, Tomaselli L O, Rocha M G, Oliveira D, Roulet J F, Geraldeli S: Effect of elastomeric urethane monomer on physicochemical properties and shrinkage stress of resin composites. In: Braz Dent J, vol. 34, no. 4, pp. 135-142, 2023. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN6198, This study aimed to evaluate the effect of an elastomeric urethane monomer (Exothane-24) in different concentrations on physicochemical properties, gap formation, and polymerization shrinkage stress of experimental resin composites. All experimental composites were prepared with 50 wt.% of Bis-GMA and 50 wt.% of TEGDMA, to which 0 wt.% (control), 10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.% of Exothane-24 were added. Filler particles (65 wt.%) were then added to these resin matrixes. Ultimate tensile strength (UTS: n = 10), flexural strength (FS: n = 10), flexural modulus (FM: n = 10), hardness (H: n = 10), hardness reduction (HR: n = 10), degree of conversion (DC: n = 5), gap width (GW: n = 10), and polymerization shrinkage stress in Class I (SS-I: n = 10) and Class II (SS-II: n = 10) simulated configuration. All test data were analyzed using one-way ANOVA and Tukey's test (alpha = 0.05; = 0.2). Exothane-24 in all concentrations decreased the H, HR, DC, GW, SS-I, and SS-II (p < 0.05) without affecting the UTS, and FS (p > 0.05). Reduction in FM was observed only in the Exothane 40% and 30% groups compared to the control (p < 0.05). Exothane-24 at concentrations 20% and 30% seems suitable since it reduced GW and polymerization SS without affecting the properties of the composite resins tested, except for H. | ||
37. | Maucoski C, Price R B, Rocha M G, Roulet J F, Sullivan B: Ability of short exposures from laser and quad-wave curing lights to photo-cure bulk-fill resin-based composites. In: Dent Mater, vol. 39, no. 3, pp. 275-292, 2023. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5703, OBJECTIVE: This study investigated the ability of a laser, and a 'quad-wave' LCU, to photo-cure paste and flowable bulk-fill resin-based composites (RBCs). METHODS: Five LCUs and nine exposure conditions were used. The laser LCU (Monet) used for 1 s and 3 s, the quad-wave LCU (PinkWave) used for 3 s in the Boost and 20 s in the Standard modes, the the multi-peak LCU (Valo X) used for 5 s in the Xtra and 20 s in the Standard modes, were compared to the polywave PowerCure used in the 3 s mode and for 20 s in the Standard mode, and to the mono-peak SmartLite Pro used for 20 s. Two paste consistency bulk-fill RBCs: Filtek One Bulk Fill Shade A2 (3 M), Tetric PowerFill Shade IVA (Ivoclar Vivadent), and two flowable RBCs: Filtek Bulk Fill Flowable Shade A2 (3 M), Tetric PowerFlow Shade IVA (Ivoclar Vivadent) were photo-cured in 4-mm deep x 4-mm diameter metal molds. The light received by these specimens was measured using a spectrometer (Flame-T, Ocean Insight), and the radiant exposure delivered to the top surface of the RBCs was mapped. The immediate degree of conversion (DC) at the bottom, and the 24-hour Vickers Hardness (VH) at the top and bottom of the RBCs were measured and compared. RESULTS: The irradiance received by the 4-mm diameter specimens ranged from 1035 mW/cm(2) (SmartLite Pro) to 5303 mW/cm(2) (Monet). The radiant exposures between 350 and 500 nm delivered to the top surface of the RBCs ranged from 5.3 J/cm(2) (Monet in 1 s) to 26.4 J/cm(2) (Valo X), although the PinkWave delivered 32.1 J/cm(2) in 20 s 350 to 900 nm. All four RBCs achieved their maximum DC and VH values at the bottom when photo-cured for 20 s. The Monet used for 1 s and the PinkWave used for 3 s on the Boost setting delivered the lowest radiant exposures between 420 and 500 nm (5.3 J/cm(2) and 3.5 J/cm(2) respectively), and they produced the lowest DC and VH values. CONCLUSIONS: Despite delivering a high irradiance, the short 1 or 3-s exposures delivered less energy to the RBC than 20-s exposures from LCUs that deliver> 1000 mW/cm(2). There was an excellent linear correlation (r > 0.98) between the DC and the VH at the bottom. There was a logarithmic relationship between the DC and the radiant exposure (Pearson's r = 0.87-97) and between the VH and the radiant exposure (Pearson's r = 0.92-0.96) delivered in the 420-500 nm range. | ||
36. | Kose Jr C, Oliveira D, Pereira P N R, Rocha M G: Using artificial intelligence to predict the final color of leucite-reinforced ceramic restorations. In: J Esthet Restor Dent, vol. 35, no. 1, pp. 105-115, 2023. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5680, OBJECTIVES: The aim of this study was to evaluate the accuracy of machine learning regression models in predicting the final color of leucite-reinforced glass CAD/CAM ceramic veneer restorations based on substrate shade, ceramic shade, thickness and translucency. METHODS: Leucite-reinforced glass ceramics in four different shades were sectioned in thicknesses of 0.3, 0.5, 0.7, and 1.2 mm. The CIELab coordinates of each specimen were obtained over four different backgrounds (black, white, A1, and A3) interposed with an experimental translucent resin cement using a calibrated spectrophotometer. The color change (CIEDE2000) values, as well as all the CIELab values for each one of the experimental groups, were submitted to 28 different regression models. Each regression model was adjusted according to the weights of each dependent variable to achieve the best-fitting model. RESULTS: Different substrates, ceramic shades, and thicknesses influenced the L, a, and b of the final restoration. Of all variables, the substrate influenced the final ceramic shade most, followed by the ceramic thickness and the L, a, and b of the ceramic. The decision tree regression model had the lowest mean absolute error and highest accuracy to predict the shade of the ceramic restoration according to the substrate shade, ceramic shade and thickness. CLINICAL SIGNIFICANCE: The machine learning regression model developed in the study can help clinicians predict the final color of the ceramic veneers made with leucite-reinforced glass CAD/CAM ceramic HT and LT when cemented with translucent cements, based on the color of the substrate and ceramic thicknesses. | ||
35. | Fraga M A A, Oliveira D, Rocha M G, Sinhoreti M A C, Correr-Sobrinho L, Correr A B: Curing profile and marginal gap formation using a liner containing long-wavelength-absorbing photoinitiator: an in vitro study. In: Lasers Med Sci, vol. 38, no. 1, pp. 69, 2023. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5684, The aim was to evaluate the marginal-gap formation and curing profile of a new restorative technique using a liner with long-wavelength-absorbing photoinitiator (LWAP). Box-shaped preparations (6 mm x 4 mm x 4 mm) were made in third molars. All samples were treated with Clearfill SE Bond and divided into 4 groups (n = 5), according to restorative technique used: (1) incremental technique (INC-Technique); (2) camphorquinone-based liner (CQ-Liner) + bulk-fill resin composite; (3) LWAP-based liner (LWAP-Liner) + bulk-fill resin composite; and (4) bulk-fill technique without liner (BF-Technique). The marginal gaps (%) for all the samples were measured using micro-computed tomography. The restorations were cross-sectioned, and the degree of conversion (DC) and Knoop microhardness were evaluated at different depths (0.3, 1, 2, 3, and 4 mm). INC-Technique, CQ-Liner, and LWAP-Liner groups showed significantly fewer marginal gaps than those from the BF-Technique group. The BF-Technique specimens had the lowest DC and microhardness in depth. All the other techniques presented similar degree of conversion and microhardness at all the depths. The use of liners, regardless of the photoinitiator system, decreased the marginal-gap formation and improved the curing profile of bulk-filling restoration technique. | ||
34. | Floriani F, Lopes G C, Cabrera A, Duarte W, Zoidis P, Oliveira D, Rocha M G: Linear Accuracy of Intraoral Scanners for Full-Arch Impressions of Implant-Supported Prostheses: A Systematic Review and Meta-Analysis. In: Eur J Dent, vol. 17, no. 4, pp. 964-973, 2023. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5683, This article compares the accuracy of intraoral scanners (IOSs) used in the digital impression of full arches to fabricate implant-supported complete prostheses. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered in the Open Science Framework (DOI 10.17605/OSF.IO/CPM9K). Six electronic databases, gray literature databases, and a manual search were performed in April 2022. Studies that evaluated the accuracy of intraoral scan impressions compared with conventional impressions in full-arch impressions were included for complete implant-supported prostheses. In addition, an adapted checklist for reporting in vitro studies was used to assess the risk of bias. Meta-analysis was conducted using a random-effects Hunter- Schmidt model. Nine studies were included in the analysis. IOS impressions present higher accuracy (137.86 mum) than conventional impressions (182.51 mum) (p<0.001). The heterogeneity of the study's methodology was I2(1/4)18.34. However, impression accuracy varies significantly with scan body type, IOS type, scanning strategy, and modification technique. For most IOS systems, the acceptable clinical threshold of linear accuracy of 200 mum can be achieved, except for the True Definition Scanner in one of the studies. Based on the results of the included studies, digital impressions using IOS present similar or better linear accuracy than conventional impression techniques. | ||
33. | Detogni A C, Abuna G, Mendonca M J, Rocha M G, Silva M P, Sinhoreti M A C, Camilotti V: Effect of an Experimental Ozone-based Desensitizing Gel on Tooth Sensitivity and In-office Dental Bleaching. In: Journal of Advances in Medicine and Medical Research, vol. 35, no. 19, pp. 283-295, 2023. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5922, <p><strong>Aims: </strong>This study evaluated bleaching efficacy (BE), tooth sensitivity (TS), and enamel microstructure after in-office dental bleaching treatment with experimental desensitizing gel containing ozone (O<sub>3</sub>).</p><p><strong>Study Design: </strong>For the TS and BE analysis, forty third molars were divided into two groups (n=20): OF-B, ozone-free desensitizer and bleaching agent; O-B, 16 ppm ozonized desensitizer and bleaching agent.</p><p><strong>Place and Duration of Study:</strong> Dental Clinic of the State Western University of Parana, between June 2019 and April 2020.</p><p><strong>Methodology:</strong> The calculation indicated that 20 teeth per group, totalizing 40 teeth (30 patients), would be sufficient to detect significant differences in TS and BE (power of 80%, significance level of 5%). Dental bleaching was performed with 35% hydrogen peroxide. TS was assessed using a visual analog scale, and BE was assessed using the Vitapan Classical color visual scale. After tooth extraction, the enamel microstructure was evaluated by micromorphological analysis using a scanning electron microscope (SEM). For this analysis, eighty third molars were used, divided into four groups (n=20): OF-B and O-B previously described; OF-WB, ozone-free desensitizer without bleaching agent; O-WB, ozonated desensitizer 16 ppm without bleaching agent. Statistical analyzes of all variables were performed with a significance level of α = 0.05. The Mann-Whitney test was used for intergroup analysis for two outcomes, and the Friedman test was used for intragroup analysis. McNemar's exact test compared the risks of tooth sensitivity in the two groups (α = 0.05).</p><p><strong>Results:</strong> TS was higher in the OF-B group. No significant differences were observed in BE. No modification was demonstrated in the enamel microstructure by the action of O<sub>3</sub>.</p><p><strong>Conclusion:</strong> The experimental gel containing O<sub>3</sub> is a promising desensitizing agent for clinical use, reducing tooth sensitivity, without interfering with the color achieved by dental bleaching and in the microstructure of tooth enamel.</p> | ||
32. | Chiang C C, Xia X, Craciun V, Rocha M G, Camargo S E A, Rocha F R G, Gopalakrishnan S K, Ziegler K J, Ren F, Esquivel-Upshaw J F: Enhancing the Hydrophobicity and Antibacterial Properties of SiCN-Coated Surfaces with Quaternization to Address Peri-Implantitis. In: Materials (Basel), vol. 16, no. 17, pp. 5751, 2023. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5923, Peri-implantitis is a major cause of dental implant failure. This disease is an inflammation of the tissues surrounding the implant, and, while the cause is multi-factorial, bacteria is the main culprit in initiating an inflammatory reaction. Dental implants with silicon carbonitride (SiCN) coatings have several potential advantages over traditional titanium implants, but their antibacterial efficiency has not yet been evaluated. The purpose of this study was to determine the anti-bacterial potential of SiCN by modifying the surface of SiCN-coated implants to have a positive charge on the nitrogen atoms through the quaternization of the surface atoms. The changes in surface chemistry were confirmed using contact angle measurement and XPS analysis. The modified SiCN surfaces were inoculated with Streptococcus mutans (S. mutans) and compared with a silicon control. The cultured bacterial colonies for the experimental group were 80% less than the control silicon surface. Fluorescent microscopy with live bacteria staining demonstrated significantly reduced bacterial coverage after 3 and 7 days of incubation. Scanning electron microscopy (SEM) was used to visualize the coated surfaces after bacterial inoculation, and the mechanism for the antibacterial properties of the quaternized SiCN was confirmed by observing ruptured bacteria membrane along the surface. | ||
2022 |
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31. | Zoidis P, Motlagh N, Tarte S, Vaughan C, Phu L, Vandewater L, Abujbara N, Paz G D L, Al-Shafadi M, Oliveira D, Rocha M G: Dental students' perspectives on three intraoral scanners and CAD/CAM systems before and after a pre-clinical elective course in digital dentistry. In: J Clin Exp Dent, vol. 14, no. 10, pp. e803-e808, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5521, BACKGROUND: Intraoral scanners (IOS) are gaining interest in Dentistry for their ability to capture digital impressions of the oral cavity. These digital impressions facilitate the fabrication of indirect restorations using CAD/CAM technology. This study aimed to describe an elective course given to predoctoral dental students on the topic of Digital Dentistry and assess their learning outcomes and system preferences. MATERIAL AND METHODS: Three IOS were evaluated by eight students enrolled in a Digital Dentistry elective course. These systems included Emerald S (Planmeca), Cerec Omnicam (Denstply Sirona), and True Definition (3M/Midmark). After a literature review and a hands-on session were completed for each system, the students provided their perspectives on various factors such as ease of use, organization, and user-friendliness in a qualitative narrative of each system and quantitatively through a six-items survey. RESULTS: Survey data suggests that the student cohort showed higher levels of previous familiarity, user preference, and clinical confidence in the Cerec and Planmeca systems as opposed to the True Definition system. Qualitatively, the students felt CEREC was the more educationally useful system to learn and presented with more ease of use, functionality, and efficacy than the other two systems. CONCLUSIONS: While each system proved to have its unique benefits and drawbacks, students' attitudes towards the Planmeca and Cerec systems were generally positive, while True Definition's evaluation was limited. Students appreciated their experiences throughout this elective, familiarizing themselves with various digital systems. Key words:Digital Dentistry, Intraoral Scanners, CAD/CAM, Dental Education, Learning Curve. | ||
30. | Roulet J F, Sinhoreti M A C, Pontes S, Rocha M G: Two-body wear resistance and fatigue survival of new Y-TZP and ATZ ceramics made with a new slip-casting method. In: J Mech Behav Biomed Mater, vol. 136, pp. 105535, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5520, BACKGROUND: Dental zirconium oxide restorations are milled from pre-sintered blocks or disks which are produced either with high isostatic pressure (HIP) or, simpler, a slurry technique. The objective was to perform a fatigue test and an in vitro wear simulation of two ceramics, yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) ceramic and a hybrid zirconium oxide-aluminum oxide ceramic, (ATZ) both produced either the classical way using high isostatic pressure (HIP, control) or with a slurry technique. MATERIALS AND METHODS: Ten discs/group were subjected to a cyclic biaxial fatigue test using a staircase approach under water at 37 degrees C in a dynamic universal testing machine. The 2-body wear test was performed on eight lapped 12 mm thick cylindrical samples subjected to spherical (o 6 mm) leucite ceramic antagonists in a CS-4 chewing simulator at 49 N force and 0.7 mm lateral movement for 600 k cycles and 4167 thermal cycles (5-55 degrees C). Volumetric wear was calculated based on laser-scanned surfaces. Selected samples of both tests were viewed in SEM. RESULTS: All the ceramic specimens produced using the HIP method survived up to 1.2 M cycles with the maximum load of the equipment (1000 N) loading the specimens up to 1527 MPa. The fatigue limit stress at 1.2 M cycles for the Slurry ATZ samples was 946 MPa. For the Slurry Y-TZP samples the fatigue limit stress at 1.2 M cycles was 658 MPa. At 600 k cycles, all zirconium oxide ceramics showed no measurable wear and had a highly polished appearance. The leucite ceramic antagonists wear developed in a linear way. There was no difference between the materials produced with the slurry and the HIP process. ATZ ceramic produced significantly more wear than 3Y- TZP ceramic. CONCLUSIONS: The HIP method provided higher fatigue strength than the Slurry manufacturing method. All HIP ceramics surpassed the limit threshold (1527 MPa) of the testing machine. The tested ceramics did not show any measurable wear but had worn the leucite reinforced glass ceramic antagonists for a considerable amount. | ||
29. | Rocha M G, Ottenga M E, Zoidis P, Pontes S, Reis A F, Oliveira D: Effect of dental headlights spectrum on the polymerization and working time of light-cured resin composites. In: J Clin Exp Dent, vol. 14, no. 6, pp. e492-e498, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5506, BACKGROUND: The use of dental headlights is a common practice to better illuminate the operatory field and achieve excellence in restorative dentistry. However, visible light-cured dental materials can have reduced working time under headlight illumination. The aim of this study was to evaluate the influence of the spectral irradiance power of two dental headlights on the degree of polymerization and working time of light-curable dental composites. MATERIAL AND METHODS: Two headlights, StarLight Nano 3 (StarMed) (SN) and Zeon Endevour XL (Orascoptic) (ZE) were characterized using a spectrophotometer coupled to an integrating sphere (MARC(R) Light Collector, BlueLight Analytics). The degree of conversion of the two composites, Filtek Supreme (3M) and Tetric Prime (Ivoclar Vivadent), was evaluated using an FTIR spectroscope (NicoletTM iS20, Thermo Fisher). RESULTS: Both headlights emitted a significant amount of blue light. The Zeon headlamp without filter emitted a broader spectrum with lower blue intensity and higher CRI than the White LED of the Nano 3. The Zeon headlamp with the blue blocking filter emitted a broader spectrum than the Orange LED of the Nano 3. There were no differences in the degree of conversion and working time of the Filtek Supreme and Tetric Prime composites when illuminated by the different headlamps. Both Zeon and the White LED of the Nano 3 were capable to cure the composites within only 5-10 minutes of irradiation. There were no changes in the degree of conversion of the composites when the Orange LED of the Nano 3 or the blue blocking filter of the Zeon were used. CONCLUSIONS: Both headlights reduced the working time of light-cured materials. The use of orange filters prevented the composite polymerization and maintained the working time. Key words:Surgical Headlight, degree of conversion, working time, light-curing. | ||
28. | Rocha M G, Oliveira D, Felix C, Roulet J F, Sinhoreti M A C, Correr A B: Beam Profiling of Dental Light Curing Units Using Different Camera-Based Systems. In: Eur J Dent, vol. 16, no. 1, pp. 64-79, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN4235, OBJECTIVE: This study aimed to perform the beam profile of dental light-curing units (LCUs) using mirrorless and smartphone cameras and correlate it to a camera-based laser beam profiling system. MATERIALS AND METHODS: Three LCUs were evaluated (Radii Plus; Bluephase G2; and VALO Cordless). The spectral power of the LCUs was measured by using a spectrophotometer. The light emitted from the LCUs was projected onto a glass diffuser, and the images were recorded by using a mirrorless camera (NEX-F3), a smartphone (iPhone) and a camera-based beam profiler. Bandpass optical-filters were used, and for each LCU, the total spectral power output was integrated to calibrate the images. Statistical analysis was performed by digital image correlation (pixel by pixel) using Pearson's correlation (alpha = 0.05; beta = 0.2). RESULTS: The beam profile images showed nonuniform radiant emittance and spectral emission distributions across all the LCUs light tip. A strong correlation was found among cameras (Pearson's r = 0.91 +/- 0.03 with 95% confidence interval [CI]: 0.88-0.94 for the NEX-F3 and Pearson's r = 0.88 +/- 0.04 with 95% CI: 0.84-0.92 for the iPhone). CONCLUSION: The standard Ophir beam profile system presented the most accurate distribution, but the mirrorless and smartphone cameras presented a strong correlation in the irradiance distribution of the beam profile images. Alternative cameras can be used to perform light beam profile of dental LCUs, but caution is needed as the type of sensor, image bit depth, and image processing are important to obtain accurate results. | ||
27. | Rocha M G, Oliveira D, Menezes L R, Roulet J F, Sinhoreti M A C, Correr A B: The use of an elastomeric methacrylate monomer (Exothane 24) to reduce the polymerization shrinkage stress and improve the two-body wear resistance of bulk fill composites. In: Dent Mater, vol. 38, no. 2, pp. e43-e57, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN4375, OBJECTIVES: Characterize the chemical structure of an elastomeric monomer (Exothane 24) and evaluate the degree of conversion (DC), polymerization shrinkage stress (PSS), rate of polymerization (Rp), flexural strength (F(Strenght)), flexural modulus (F(Modulus)), Vickers hardness (V(Hardness)) and two-body wear resistance of dental bulk fill composites (BFCs) containing Exothane 24. METHODS: The Exothane 24 was characterized using mass spectroscopy, elemental analysis, (13)C- and (1)H NMR. BFCs were formulated containing Exothane 24 (E10, E25, and E50). Similar BFCs containing regular UDMA (U10, U25, and U50), commercial conventional, and BFCs were used as control groups. ATR-FTIR spectroscopy was used to measure DC and the Rp of the composites. The PSS was measured using the universal testing machine method. Specimen bars were used to assess the F(Strenght), F(Modulus,) and V(Hardness). RBCs were submitted to a two-body wear test using a chewing simulator machine; the rate and volumetric wear loss were evaluated using an optical scanner. Data were analyzed statistically with alpha = 0.05 and beta = 0.2. RESULTS: Exothane 24 is a urethane isophorone tetramethyl methacrylate monomer with polymerization stress-relieving properties. No differences were found in the DC up to 4 mm in depth for E25. All BFCs had similar F(Strenght), except for E50. E25 had the lowest volumetric wear loss and wear rate. E25 had approximately 30% lower PSS and slower Rp than commercial BFCs with similar wear resistance to conventional commercial composites. SIGNIFICANCE: The Exothane 24 reduced the PSS and increased the wear resistance of BFCs; however, the formulation is important to optimize the properties of the BFCs. | ||
26. | Rocha M G, Maucoski C, Roulet J F, Price R B: Depth of cure of 10 resin-based composites light-activated using a laser diode, multi-peak, and single-peak light-emitting diode curing lights. In: J Dent, vol. 122, pp. 104141, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN4677, OBJECTIVES: To evaluate the depth of cure (DOC) of ten contemporary resin-based composites (RBCs), light-cured using different LCUs and exposure times. METHODS: The power, radiant emittance, irradiance, radiant exposure (RE), and beam profiles from a laser (M, Monet), a multi-peak (V, Valo Grand), and single-peak (S, SmartLite Pro) LCU were measured. The DOC was measured using a 6-mm diameter metal mold and a solvent dissolution method to remove the uncured RBC. The length of the remaining RBC was divided by 2. The exposure times were: 1 s and 3 s for M, 10 s and 20 s for V, and 10 s and 20 s for S. Data were analyzed using: Bland-Altman distribution, Pearson's Correlation, and an artificial neural network (ANN) to establish the relative importance of the factors on the DOC (alpha=0.05; beta=0.2). RESULTS: Significant differences were found in the DOC achieved by the different LCUs and composites. The laser LCU emitted the highest power, radiant emittance is used above and in the tables and delivered the highest irradiance. However, this LCU used for 1 s delivered the lowest RE and produced the shortest DOC in all ten RBCs. The ANN demonstrated that the RE is the most critical factor for the DOC. Bland-Altman comparisons showed that the DOCs achieved with the laser LCU used for 1 s were between 17 and 34% shorter than the other conditions. CONCLUSIONS: Although the laser LCU cured all 10 RBCs when used for 1 s, it produced the shallowest DOC, and some RBCs did not achieve their minimum DOC threshold. The RE and not the irradiance was the most important factor in determining the DOC of these 10 RBCs. CLINICAL SIGNIFICANCE: Despite delivering high power and irradiance, the laser used for l s delivered a lower radiant exposure than the conventional LCUs used for 10 s. This resulted in a shorter DOC. | ||
25. | Oliveira D, Rocha M G, Zoidis P, Pereira P, Ribeiro A P: The effect of different pulp capping methods on the intrapulpal temperature when using light-cured procedures. In: J Clin Exp Dent, vol. 14, no. 8, pp. e633-e638, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5514, BACKGROUND: To evaluate the intra-pulpal temperature during different direct pulp capping methods and light-cured procedures. MATERIAL AND METHODS: Class I preparations 5 mm long, 4 mm wide and 4 mm deep were performed in extracted third molars, leaving 0.5 mm of dentin at the pulpal floor with a 1 mm diameter of pulp exposure. Teeth were placed in a customized oral cavity chamber simulator in which the initial temperature was standardized at 36oC. The overall temperature variations (oC) in the pulp chamber during the light-activation processes were recorded live using an infrared camera (FLIR ONE PRO, FLIR Systems). The liners and bases evaluated were: Dycal (Dentisply), TheraCal LC (Bisco), Biodentin (Septodent), Vitrebond Plus (3M/ESPE), and Fuji IX GP (GC), followed by restoration with a bulk fill composite (EvoCeram Bulk Fill, Ivoclar Vivadent). All light-activation procedures were performed with the VALO Grand (Ultradent) light-curing unit. A power analysis was conducted to determine the sample size to provide a power of at least 0.8 with alpha=0.05. Statistical analyses were performed using ANOVA and Tukey's test for multiple comparisons. RESULTS: The intrapulpal temperature increased above a 10oC to 20oC threshold difference for all liners and bases that were light cured. When added as second layers, neither of those could provide thermal insulation following additional light-activated procedures (p=0.25). The higher the number of procedures requiring light-activation, the longer the pulp temperature remained in those increased temperature thresholds. CONCLUSIONS: For direct pulp capping procedures, a reduced number light activation procedures should be indicated to reduce the time intra-pulpal temperature rises above a 10oC threshold. Key words:Liner, base, calcium hydroxide, glass ionomer, dental adhesive, bulkfill composite. | ||
24. | Oliveira D, Rocha M G: Dental Light-Curing-Assessing the Blue-Light Hazard. In: Dent Clin North Am, vol. 66, no. 4, pp. 537-550, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5513, This article focuses on the current understanding and concerns over the blue-light hazard when using dental light-curing units. It also provides information and safety protocols to guide the practitioner in making important decisions regarding dental personnel's health and the quality of dental restorations. | ||
23. | Nobre C F A, Feitosa V P, Fronza B M, Leal A M C, Rocha M G, Roulet J F, Sinhoreti M A C: Physicochemical properties of experimental resin-based composites using tris(trimethylsilyl)silane associated with diphenyl iodonium hexafluorophosphate (DPIHP) salt. In: J Mech Behav Biomed Mater, vol. 130, pp. 105169, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN4379, The purpose was to evaluate the effect of tris(trimethylsilyl)silane (TTMSS) associated with diphenyl iodonium hexafluorophosphate (DPIHP) on the polymerization shrinkage stress (PSS), mechanical properties, color change (CC), and degree of conversion (DC) of resin-based composites (RBCs). Experimental RBCs containing 35 wt% of organic matrix (10.2 wt% BisGMA, 11.1 wt% BisEMA10 and UDMA and 2.1 wt% TEGDMA) and 65 wt% filler (13 wt% fumed silica and 52 wt% BaBSiO(2)) were assigned to six groups: control (0.2 wt% CQ, 0.5 wt% DMAEMA); TD05 (0.2 wt% CQ, 0.5 wt% TTMSS, 0.5 wt% DPIHP); TD10 (0.2 wt% CQ, 1 wt% TTMSS, 0.5 wt% DPIHP); DTD (0.2 wt% CQ, 0.25 wt% of DMAEMA, 0.25 wt% TTMSS, 0.5 wt% DPIHP); DT (0.2 wt% CQ, 0.25 wt% DMAEMA, 0.25 wt% TTMSS); and T05 (0.2 wt% CQ, 0.25 wt% TTMSS). The experimental formulations were submitted to the following tests: DC; PSS; CC; rate of polymerization (Rp); depth of cure by Knoop hardness; flexural strength; and flexural modulus. TTMSS showed no effect on the DC, Rp, and mechanical properties of the RBCs. DMAEMA reacted with TTMSS and reduced the Rp; the RBCs containing no DMAEMA showed no reduction in CC. DT showed the lowest PSS mean value among the groups. TTMSS differed from DMAEMA only when used in combination with DPIHP, which significantly improved the DC, maximum Rp, and mechanical properties of the RBCs tested. Based on the artificial ageing results, TTMSS was ineffective in reducing CC in the RBCs tested. | ||
22. | Lopes G, Matos J D M, Queiroz D A, Tribst J P M, Ramos N C, Rocha M G, Barbosa A B, Bottino M A, Borges A L S, Nishioka R S: Influence of Abutment Design on Biomechanical Behavior to Support a Screw-Retained 3-Unit Fixed Partial Denture. In: Materials (Basel), vol. 15, no. 18, pp. 6235, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5516, This study aimed to evaluate the biomechanical behavior of Morse taper implants using different abutments (CMN abutment [(CMN Group] and miniconical abutments [MC Group]), indicated to support a screw-retained 3-unit fixed partial denture. For the in vitro test, polyurethane blocks were fabricated for both groups (n = 10) and received three implants in the "offset" configuration and their respective abutments (CMN or MC) with a 3-unit fixed partial denture. Four strain gauges were bonded to the surface of each block. For the finite element analysis, 3D models of both groups were created and exported to the analysis software to perform static structural analysis. All structures were considered homogeneous, isotropic, and elastic. The contacts were considered non-linear with a friction coefficient of 0.3 between metallic structures and considered bonded between the implant and substrate. An axial load of 300 N was applied in three points (A, B, and C) for both methods. The microstrain and the maximum principal stress were considered as analysis criteria. The obtained data were submitted to the Mann-Whitney, Kruskal-Wallis, and Dunn's multiple comparison test (alpha = 5%). The results obtained by strain gauge showed no statistical difference (p = 0.879) between the CMN (645.3 +/- 309.2 muepsilon) and MC (639.3 +/- 278.8 muepsilon) and allowed the validation of computational models with a difference of 6.3% and 6.4% for the microstrains in the CMN and MC groups, respectively. Similarly, the results presented by the computational models showed no statistical difference (p = 0.932) for the CMN (605.1 +/- 358.6 muepsilon) and MC (598.7 +/- 357.9 muepsilon) groups. The study concluded that under favorable conditions the use of CMN or MP abutments to support a fixed partial denture can be indicated. | ||
21. | Lara L, Rocha M G, Menezes L R, Correr A B, Sinhoreti M A C, Oliveira D: Mechanical properties of bulk-fill composite resin with or without a final layer of conventional composite resin. In: Gen Dent, vol. 70, no. 3, pp. 60-64, 2022. (Type: Journal Article | Abstract | Links)@article{RN4678, The objective of this in vitro study was to evaluate the mechanical properties of different bulk-fill composite resins with or without a final layer of conventional composite resin. The null hypothesis was that the mechanical properties of the material would not change regardless of the addition of a layer of conventional composite. Bar-shaped specimens (25 x 2 x 2 mm) were made from 4 different bulk-fill composites (Filtek One Bulk Fill, Filtek Bulk Fill Flowable, Tetric EvoCeram Bulk Fill, and Tetric EvoCeram Bulk Fill Flow) with or without a final layer of a conventional composite of the same brand (Filtek Supreme for the Filtek materials and Tetric EvoCeram for the Tetric materials). Each specimen was light cured at 2 equidistant points using a multiwave curing light with a power output of 20 J/cm(2). All of the specimens were subjected to a 3-point bending test in a universal testing machine at a crosshead speed of 0.75 +/- 0.25 mm/min and a load rate of 50 +/- 16 N/min, and the flexural strength and elastic modulus were calculated. The mean flexural strength and elastic modulus values were analyzed using 1-way analysis of variance, and then the Tukey test was applied for multiple comparisons between groups (alpha = 0.05). When a final layer of a conventional composite of the same brand was added, the mean flexural strength of the Tetric groups slightly decreased, while that of the Filtek groups did not change. Application of a final layer of conventional composite resulted in a slight increase in the mean elastic modulus of the Filtek groups and either no change or a slight decrease in the Tetric groups. The addition of a final layer of conventional composite resin did not seem to improve the mechanical properties of any of the tested bulk-fill materials. The addition of a final layer of conventional composite resin can affect the mechanical properties of bulk-fill materials; however, it seems these effects are dependent on the type of conventional composite resin used for the final layer. | ||
20. | Lalama M, Rocha M G, O'Neill E, Zoidis P: Polyetheretherketone (PEEK) Post and Core Restorations: A 3D Accuracy Analysis between Heat-Pressed and CAD-CAM Fabrication Methods. In: J Prosthodont, vol. 31, no. 6, pp. 537-542, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN4237, PURPOSE: The purpose of this study was to evaluate the accuracy of polyetheretherketone (PEEK) based post and core restorations using heat-pressed and computer-aided design and computer-aided manufacturing (CAD-CAM) methods. MATERIALS AND METHODS: Post and core patterns (n = 10) were fabricated using an acrylic pattern resin and each pattern was scanned to generate a resin pattern standard tessellation file (STL-R) to be used as the standard control group for the 3D profilometric analysis. The STL-R files were loaded into a computer-aided manufacturing (CAM) machine and a milling disk made of a modified PEEK-based polymer with 20% ceramic fillers was milled into post and core restorations. Each original post and core resin pattern was sprued, invested and pressed using pellets made of the same PEEK material and a PEEK pressing unit. The resulting post and core restorations from the CAD-CAM and heat-pressed methods were scanned to generate STL-M (milled) and STL-P (heat-pressed) files, respectively. STL-M and STL-P files were digitally aligned and compared to STL-R files using a 3D analysis software. The 3D spatial distribution deviation was exported, and the statistical analysis was performed using the 95% CI deviation distribution from the Gaussian function subtraction. The statistical outcome for each group was merged and a 3D color-coded map was created showing the average deviation (alpha = 0.05). RESULTS: The heat-pressed post and core restoration showed 79 +/-6% of the areas within +/-50 microm while the CAD-CAM post-and-core restoration showed 66 +/-9%. The CAD-CAM post and core restorations show 6 +/-5% of the areas above the ideal for marginal adaptation limit threshold of 200 microm, while only 0.7 +/-0.7% was found for the heat-pressed. CONCLUSIONS: The heat-pressed method to manufacture PEEK-based post and core restorations showed higher accuracy than the CAD-CAM method. | ||
19. | Floriani F, Brandfon B A, Sawczuk N J, Lopes G C, Rocha M G, Oliveira D: Color difference between the vita classical shade guide and composite veneers using the dual-layer technique. In: J Clin Exp Dent, vol. 14, no. 8, pp. e615-e620, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5517, BACKGROUND: The purpose of this in vitro study was to evaluate the color difference between the Vita Classical Shade Guide and composite veneers using the dual-layer technique. MATERIAL AND METHODS: Thirty samples were fabricated using a custom-made mold (Easy Layering Shade Guide Kit, 3M) using two resin composites: Filtek Supreme Ultra (3M); and Estelite Omega (Tokuyama) (n=3). The composite veneers were made by layering the different enamel and body or dentin shades from each composite. The color measurements were taken using a spectrophotometer (Vita Easyshade V(R), Vita Zahnfabrik). The DeltaE00 between the Vita Classical Shade Guide (Vita Zahnfabrik) and the composite veneers were calculated using the CIEDE2000 formula. RESULTS: For the composite veneers using Filtek Supreme Ultra, the best match for A1 Vita shade was achieved layering either EA1 with DA2 or DA3; EA2 with DA1 or DA2 (DeltaE00= 1.53 ~ 1.96 +/- 0.4). For A2 Vita shade the best match would be EA3 with DA3 or EA3 with DA2 (DeltaE00= 1.40 ~ 1.85 +/- 0.1); or for A3 Vita shade the best match would be EA3 with DA2 2.50+/-(0.6). For the composite veneers using Estelite Omega, the were no best match for neither A1, A2 or A3 Vita shade (DeltaE00> 2.5). CONCLUSIONS: The combination of enamel and dentin shades from Filtek Supreme Ultra provided acceptable color match for A1, A2 and A3 shades from the Vita Shade Guide, while Estelite Omega did not provide acceptable color match for any of the Vita Shade Guide standard shades tested. Key words:Color, color matching, optical properties, resin composite, layering. | ||
18. | Favarao J, Oliveira D, Zanini M M, Rocha M G, Ogliari F A, Correr-Sobrinho L, Sinhoreti M A C: Effect of light attenuation through veneers on bond strength of adhesives with photoinitiator combinations. In: Braz Oral Res, vol. 36, pp. e075, 2022. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN5357, This study aimed to evaluate the effect of light attenuation through ceramic veneers and resin cement on degree of conversion (DC), cohesive strength (CS), and microshear bond strength (muSBS) of experimental adhesive systems. Experimental etch-and-rinse and self-etch adhesives were combined with different ratios of camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) photoinitiators: CQ-only; 3CQ:1TPO; 1CQ:1TPO; 1CQ:3TPO and TPO-only. Square-shaped ceramic veneer (IPS Empress Esthetic, Ivoclar Vivadent) (n = 10; 10mm long x 10mm wide x 0.5mm thick) and resin cement specimens (Variolink Esthetic LC, Ivoclar Vivadent) (n = 10; 10 mm long x 10 mm wide and 0.3 mm thick) were prepared. Light transmittance of a multiple-peak LED (Bluephase G2, Ivoclar Vivadent) was measured through restorative materials using a spectrometer (n = 5). Adhesive specimens were analyzed for DC, CS, and muSBS by light-curing the adhesive with or without (control) ceramic veneer, and with resin cement fixed to output region of the light-curing tip (n = 10). Data were submitted to ANOVA and Tukey's test (alpha = 0.05). Total light transmittance through the restorative materials was attenuated, and this attenuation was more evident for the violet spectrum. The DC for the TPO groups in ratios up to 1CQ:1TPO was similar to the control. 1CQ:3TPO showed lower values for CS. muSBS was reduced for all groups with light attenuation, but lower values were observed for 1CQ:3TPO and TPO-only. In conclusion, light transmission was reduced with interposed restorative materials. Adhesives combined with CQ and TPO up to 1CQ:1TPO showed greater cure efficiency and mechanical properties compared with a higher amount of TPO. | ||
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17. | Roulet J F, Schepker K L, Truco A, Schwarz H C, Rocha M G: Biaxial flexural strength, crystalline structure, and grain size of new commercially available zirconia-based ceramics for dental appliances produced using a new slip-casting method. In: J Mech Behav Biomed Mater, vol. 114, pp. 104180, 2021. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN923, OBJECTIVE: The aim of this study was to evaluate the biaxial flexural strength, the crystalline structure, and the grain size of zirconia-based ceramics produced using a new slip-casting method. MATERIALS AND METHODS: Yttria-stabilized Tetragonal Zirconia Polycrystal (Y-TZP) and Alumina Toughened Zirconia (ATZ) ceramics were purchased from different manufactures. For the experimental group, ceramics produced using a patent pending slip-casting method (Slurry, Decema GmbH) was used. Slurry ceramics (n = 42) with a diameter of 14 +/- 0.2 mm were produced by a proprietary colloidal shaping process, sintered, and subsequently polished with a lapping process using 15 mum diamond particles to a thickness of 1.2 +/- 0.2 mm. For the control group, ceramics produced using the hot isostatic pressure method (HIP, Metoxit AG) were used. HIP ceramics discs (n = 42) with a diameter of 15.5 +/- 0.02 mm were produced by classical HIP method and subsequently machined to a thickness of 1.99 +/- 0.04 mm 32 discs of each ceramic were submitted to a biaxial flexural strength test using an universal testing machine at a crosshead speed of 0.5 mm/min. Statistical analyses using two-way ANOVA and Weibull distribution were performed. 2 discs of each ceramic were analyzed using X-ray diffraction for grain crystalline phase quantification. 2 discs of each ceramic were thermally etched and scanning electron microscopy images were obtained for grain size analysis (ISO 13383-1:2012). 6 discs of each ceramic were used for density measurement using the Archimedes' method. RESULTS: For both ATZ and Y-TZP ceramics, the biaxial flexural strength and the characteristic strength of ceramics produced using the Slurry method were significantly higher than ones of the ceramic produced using HIP. The structure analysis confirmed the superiority of the Slurry ceramics which had only 1.2% tetragonal phase compared to 11-16% for the HIP ceramics. Grain size distributions covered a wide range 50-800 nm; the ZrO(2) grains of the Slurry ceramics were significantly smaller than the ones of the control ceramics, while the Al(2)O(3) grain distributions were not affected by the manufacturing process. The manufacturing process had no influence on the density of both materials. CONCLUSIONS: The Slurry method using a new proprietary slip-casting method to produce Y-TZP and ATZ dental ceramics presented higher biaxial flexural strength, less monoclinic phase and smaller ZrO(2) grains. | ||
16. | Rocha M G, Roulet J F, Sinhoreti M A C, Correr A B, Oliveira D: Light Transmittance and Depth of Cure of a Bulk Fill Composite Based on the Exposure Reciprocity Law. In: Braz Dent J, vol. 32, no. 1, pp. 78-84, 2021. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN1403, The objective of this study was to evaluate the effect of the exposure reciprocity law of a multi-wave light-emitting diode (LED) on the light transmittance (LT), depth of cure (DOC) and degree of conversion in-depth (DC) of a bulk fill composite. A bulk fill composite (EvoCeram(R) bulk fill, Ivoclar Vivadent) was photoactivated using the multi-wave LED (VALO Cordless, Ultradent). The LED was previously characterized using a spectrophotometer to standardize the time of exposure when using the Standard or Xtra-Power modes with the same radiant exposure of 20J/cm2. LT was evaluated through samples of the bulk fill composite every millimeter till 4 mm in-depth. DOC was evaluated according to the ISO 4049. DC of the central longitudinal cross-section from each sample of the DOC test was mapped using FT-NIR microscopy. Data were statistically analyzed according to the experimental design (alpha=0.05; ss=0.2). The radiant exposure in the violet wavelength range for Standard and Xtra-Power was 4.5 and 5.0 J/cm2, respectively; for the blue wavelength range the radiant exposure for Standard and Xtra-Power was 15.5 and 15.0 J/cm2, respectively. There was no statistical difference in the DOC using Standard or Xtra-Power light-curing modes, but the DOC was lower than the claimed by the manufacturer (4 mm). The DC was not significantly affected by the light-curing mode up to 4 mm in depth (p>0.05). According to exposure reciprocity law, the reduction in exposure time using the same radiant exposure did not affect the depth of cure of the bulk fill composite. | ||
15. | Mohan S, Roulet J F, Abdulhameed N, Rocha M: Transferring Occlusal Anatomy from Worn Temporary Crowns to Zirconium Oxide Crowns. In: Eur J Prosthodont Restor Dent, vol. 29, no. 2, pp. 67-75, 2021. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN922, Purpose/Aim: To evaluate the accuracy of transferring the occlusal anatomy of provisional crowns to monolithic zirconium oxide crowns. Materials and Methods: From a prepared typodont-tooth (#36), ten CAD/CAM provisional polymethylethacrylate crowns were fabricated with the E4D system. Each provisional crown had its occlusion adjusted. They were scanned (E4D) and the .stl files of the crown preparations were merged with the files from the adjusted crowns (3 shape software) to produce ten polished monolithic zirconium oxide crowns. For comparison, provisional and monolithic zirconium oxide crowns were scanned (True-Definition scanner), the .stl files aligned, converted into a normalized 76x76-matrix, analyzed with ANOVA with repeated measures and Tukey's test. To generate deviation distribution tables and difference plots, .stl files (provisional crowns and monolithic zirconium oxide crowns) were merged with Geomagic software. Results: There were significant differences between provisional crowns and monolithic zirconium oxide crowns. The differences were manly in the fissure area. 86% of the calculated deviations were between + 0.06mm and - 0.04mm, 42.4% of all data points were within +/- 0.022mm with a SD of 0.005mm. The main differences were in the fissures, requiring clinically none or only minimal occlusal adjustments for these zirconium oxide crowns. | ||
14. | Lara L, Rocha M G, Menezes L R, Correr A B, Sinhoreti M A C, Oliveira D: Effect of combining photoinitiators on cure efficiency of dental resin-based composites. In: J Appl Oral Sci, vol. 29, pp. e20200467, 2021. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN2446, BACKGROUND: Camphorquinone is the most conventionally used photoinitiator in Dentistry. Although different alternative photoinitiators have been proposed, no photoinitiator was capable of completely substituting camphorquinone. The combination of photoinitiators has been considered the best alternative. OBJECTIVES: To evaluate the effect of combining Norrish type I and II photoinitiators on the cure efficiency of dental resin-based composites. METHODOLOGY: Experimental composites were produced containing different photoinitiator systems: Norrish type I-only, mono-alkyl phosphine oxide (TPO); Norrish type II-only, camphorquinone (CQ); or its combination, CQ and TPO, in a 1: 1 molar ratio. UV-vis absorption spectrophotometry was performed to assess the consumption of each photoinitiator after curing (n=3). A multi-wave LED (Bluephase(R) G2, Ivoclar Vivadent) was pre-characterized and used with a radiant exposure of 24 J/cm2. The degree of conversion was evaluated by Raman spectrometry, and the elution of the monomers by nuclear magnetic resonance analysis (n=3). Data were analyzed using ANOVA and Tukey's test (alpha=0.05; beta=0.2). RESULTS: The combination of CQ and TPO increased the consumption of the photoinitiator system compared to CQ-only (p=0.001), but presented similar consumption compared to TPO-only (p=0.52). There was no significant difference in the degree of conversion between the composites regardless of the photoinitiator system (p=0.81). However, the elution of the monomers was reduced when both photoinitiators were combined. TPO-based material presented the highest elution of monomers. CONCLUSIONS: The combination of the photoinitiator systems seems to be beneficial for the cure efficiency of dental resin-based composites. | ||
13. | Favarao J, Oliveira D, Zanini M M, Rocha M G, Correr-Sobrinho L, Sinhoreti M: Effect of curing-light attenuation on color stability and physical and chemical properties of resin cements containing different photoinitiators. In: J Mech Behav Biomed Mater, vol. 113, pp. 104110, 2021. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN920, This study aimed to evaluate the effect of light attenuation by ceramic veneers on the degree of conversion (DC), flexural strength (FS) and color change (CC) of resin cements containing different photoinitiators. Thus, samples included resin cements containing different photoinitiators: (a) camphorquinone (CQ)/ethyl 4-(dimethylamino)benzoate (EDMAB); (b) CQ/4-(N,N-dimethylamino) phenethyl alcohol (DMPOH); (c) CQ/2(dimethylamino) ethyl methacrylate (DMAEMA); (d) CQ/ethyl 4-(dimethylamino)benzoate (EDMAB) + diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide (TPO); (e) TPO; and (f) phenylbis(2.4.6-trimethylbenzoyl)phosphine oxide (BAPO). Ceramic veneers (10 x 10 mm) were 0.4 mm, 0.7 mm, 1.0 mm or 1.5 mm thick. The light irradiance of a multiple-peak LED through ceramic veneers was measured (n = 5) using a spectrometer. DC (micro-Raman spectrometer) and FS (Bar-shaped specimens) were tested in cements with and without the veneers. Color change was evaluated before and after UV artificial aging. Data were submitted to ANOVA and Tukey's test (alpha = 0.05). The violet spectrum showed the lowest irradiance values through the veneer, considering all thicknesses. BAPO had the highest DC values for all veneers. CQ/EDMAB + TPO, CQ + EDMAB, and CQ + DMPOH showed similar DC values concerning all thicknesses. TPO (1.0 mm) showed the lowest DC and FS values. CQ + TPO and CQ/amines showed similar FS values. CQ + EDMAB and CQ + DMAEMA showed the highest color change values while TPO showed the lowest. It was concluded that the physical and chemical properties of the resin cement were improved with BAPO. CQ/EDMAB + TPO showed the greatest color stability, considering all veneer groups and control, without affecting the other properties assessed. | ||
12. | Alqahtani A R, Gufran K, Silva F, Rocha M G, Chang J: A Clinical Case Report of a Potential Acute Allergic Reaction with Titanium Dental Implant. In: Case Rep Dent, vol. 2021, pp. 5592934, 2021. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN1402, Titanium hypersensitivity is rare, but it may exist among patients who need dental implant treatment. It could contribute to mild or severe peri-implant tissue hypersensitivity reactions and affect patients' oral and general health according to some clinical reports. In extreme cases, it may lead to implant failure or extraction. In this case report, a 64-year-old Caucasian female patient received a titanium implant placement on #5. Right after the implant placement, she reported the symptoms of pain, eczema, and slight extraoral swelling, along with significant burning sensation occurring intra- and extraorally. The symptoms were not released after the systemic intervention of antibiotics for six days. On retrieving her medical history, the patient reported a previous allergic reaction to jewelry-like earrings in her childhood. The diagnosis of titanium hypersensitivity was made based on the rapid onset of symptoms and her metal allergy history. Therefore, the dental implant was removed after diagnosis, and a bone allograft was used to preserve the alveolar bone volume. Immediately after implant extraction, the swelling and burning sensation were receded. A complete recovery was achieved three weeks later. The dimension of the alveolar ridge bone was found well maintained in 10 weeks follow-up visit. Conclusion. Rapid onset of peri-implant gingival swelling may indicate a hypersensitivity to titanium implant in the clinic. For patients with a history of allergy to jewelry, the hypersensitivity tests to titanium alloy such as patch test or lymphocyte transformation test should be recommended as part of the dental implant treatment plan. | ||
2019 |
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11. | Rocha M G, Oliveira D, Sinhoreti M, Roulet J F, Correr A B: The Combination of CQ-amine and TPO Increases the Polymerization Shrinkage Stress and Does Not Improve the Depth of Cure of Bulk-fill Composites. In: Oper Dent, vol. 44, no. 5, pp. 499-509, 2019. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN924, OBJECTIVES: To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the depth of cure and polymerization shrinkage stress of bulk-fill composites. METHODS AND MATERIALS: Experimental bulk-fill composites were produced containing equal molar concentrations of either CQ-amine or CQ-amine/TPO. The degree of in-depth conversion through each millimeter of a 4-mm-thick bulk-fill increment was evaluated by Fourier transform near-infrared microspectroscopy using a central longitudinal cross section of the increment of each bulk-fill composite (n=3). Light-transmittance of the multi-wave light-emitting diode (LED) emittance used for photoactivation (Bluephase G2, Ivoclar Vivadent) was recorded through every millimeter of each bulk-fill composite using spectrophotometry. The volumetric shrinkage and polymerization shrinkage stress were assessed using a mercury dilatometer and the Bioman, respectively. The flexural modulus was also assessed by a three-point bend test as a complementary test. Data were analyzed according to the different experimental designs (alpha=0.05 and beta=0.2). RESULTS: Up to 1 mm in depth, adding TPO to CQ-based bulk-fill composites increased the degree of conversion, but beyond 1 mm no differences were found. The light-transmittance of either wavelengths emitted from the multi-wave LED (blue or violet) through the bulk-fill composites were only different up to 1 mm in depth, regardless of the photoinitiator system. Adding TPO to CQ-based bulk-fill composites did not affect volumetric shrinkage but did increase the flexural modulus and polymerization shrinkage stress. CONCLUSION: Adding TPO to CQ-based bulk-fill composites did not increase the depth of cure. However, it did increase the degree of conversion on the top of the restoration, increasing the polymerization shrinkage stress. | ||
10. | Favarao J, Oliveira D, Rocha M G, Zanini M M, Abuna G F, Mendonca M J, Sinhoreti M A C: Solvent Degradation and Polymerization Shrinkage Reduction of Resin Composites Using Isobornyl Methacrylate. In: Braz Dent J, vol. 30, no. 3, pp. 272-278, 2019. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN940, The aim of this study was to use the isobornyl methacrylate (IBOMA) as a combining or substituent diluent monomer in the resin matrix of dental resin composites. Thus, the resin matrix was formulated with 60 wt% of BisGMA and 40 wt% of diluent monomers. TEGDMA as the only diluent monomer was used as control with 40 wt%, while total substitution of TEGDMA was done with 40 wt% of IBOMA. The combination of IBOMA and TEGDMA was done with 20 wt% of each monomer. To the resin matrix, 65 wt% of filler particles was added. Degree of conversion (DC) using FT-IR, flexural strength (FS), flexural modulus (FM), polymerization shrinkage by gap formation (GF), Knoop hardness (KH) and solvent degradation (SD) were evaluated. Data were analyzed using ANOVA and Tukey's test (alpha=0.05; b=0.2). The results showed that reducing or substituting TEGDMA using IBOMA did not affect the DC (0.085), FS (p=0.886) or FM (p=0.414). Also, when IBOMA was used, lower GF was found in comparison to the control containing only TEGDMA as the diluent monomer (p=0.032). However, even though all composites presented reduction in KH during the SD test, the combination of IBOMA and TEGDMA showed similar reduction in KHN in comparison to the control group (p=0.001), while the total substitution of TEGDMA with IBOMA decreased KHN after SD (p=0.041). Thus, the combination of IBOMA and TEGDMA seem to reduce SD and GF without affecting the properties of resin composites. | ||
9. | Oliveira D, Rocha M G, Correr A B, Ferracane J L, Sinhoreti M: Effect of Beam Profiles From Different Light Emission Tip Types of Multiwave Light-emitting Diodes on the Curing Profile of Resin-based Composites. In: Oper Dent, vol. 44, no. 4, pp. 365-378, 2019. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN942, Light activation is an important clinical step for achieving success in restorative procedures. This study evaluated the influence of beam profile from different light emission tip types of multiwave light-emitting diodes (LEDs) on the curing profile of resin-based composites. Experimental composites were produced containing either camphorquinone (CQ) or diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as a photoinitiator. Multiwave LEDs with either a bundle light guide tip (Bluephase G2, Ivoclar Vivadent) or a microlens tip (VALO Cordless, Ultradent) were characterized using a beam profiler. Block-shaped samples (5x5x3 mm depth) of the two composites were cured in a custom-designed mold with the multiwave LEDs positioned to compare the regions exposed to the 420-495 nm (blue) and 380-420 nm (violet) emittances. To map the curing profile, the degree of conversion (DC) of longitudinal thin cross sections from each block was evaluated using transmission FT-NIR. Radiant exposure transmitted through the composites during curing was evaluated at different thicknesses. Data were analyzed using analysis of variance and Tukey test (alpha=0.05; beta=0.2). The results indicated that there were differences in the beam profile and the overall radiant exposures transmitted through the composites using each multiwave LED (p<0.01 | ||
2018 |
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8. | Sinhoreti M A C, de Oliveira D C R S, Rocha M G, Roulet J: Fotopolimerização de materiais restauradores resinosos: uma abordagem com base em evidências para a prática clínica. In: Journal of Clinical Dentistry and Research, vol. 15, no. 1, pp. 44-53, 2018. (Type: Journal Article | Links | Dimensions | PlumX)@article{RN943, | ||
7. | Roulet J, Rocha M G, Shen C, Khudhair M M, Oliveira D C R S: Beam Profile Characterization of a Dental Light Curing Unit Using a Spectrometer-Based Method. In: Stomatology Edu Journal, vol. 5, no. 2, pp. 84-91, 2018. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN939, Aim: The study aimed to characterize a broad spectrum light curing unit (LCU) by measuring the light beam profile output of the LCU using a spectrometer-based method and correlate it with a standard camera-based beam profile method. Materials and Methods: A broad spectrum LED LCU (Ascent OL5, CAO Group) was mounted above a spectrometer (MARC® Resin Calibrator, BlueLight Analytics) at exposure distances of 1.0, 1.5 or 2.5 mm. The position of the center of the LCU was aligned with the spectrometer’s cosine corrector sensor, and then moved in 1-mm increments in the x-y plane, while concomitantly recording the irradiance. The recorded irradiance was systematically organized and reported in function of the distance from the center of the LCU exiting window. Using a standard camera-based beam profiler, a beam profile of the LCU was obtained and the above approach was emulated to the beam profile. For both methods, the irradiance decreases related to the value measured at the center position was analyzed by calculating the slope, using a linear correlation. Results: Both methods showed that moving away from the center showed decreased irradiation. The beam profile of the LCU is asymmetric. The inhomogeneity of the beam was slightly lower with farther distance from the LCU’s light exciting window. Conclusion: The spectrometer-based method was able to characterize the beam profile of the LCU and can be used in the evaluation of LCUs. | ||
6. | Oliveira D C R S, Rocha M G, Roulet J: Light curing matters: Facts often overseen by dentists. In: Stomatology Edu Journal, vol. 5, no. 4, pp. 236-242, 2018. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN936, Aim: To make dentists aware on the importance of correctly used light cure resin composites.Method: Highlighting important facts about light curing: Use of high quality light curing unit, use of the resin composite specific appropriate radiant exposure to adequately cure a resin composite, and highlighting important facts that may alter the radiant exposure received clinically by a resin composite restoration.Results: Application of this knowledge should change the behavior of dentists when it comes to light curing.Conclusions: The facts described should help educational institutes and professors to reinforce proper light curing techniques and associate training sessions within educational courses in order to improve teaching and learning. | ||
2017 |
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5. | Rocha M G, Oliveira D, Correa I C, Correr-Sobrinho L, Sinhoreti M, Ferracane J L, Correr A B: Light-emitting Diode Beam Profile and Spectral Output Influence on the Degree of Conversion of Bulk Fill Composites. In: Oper Dent, vol. 42, no. 4, pp. 418-427, 2017. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN925, OBJECTIVES: To evaluate the beam profile and the spectral output of monowave and polywave light-emitting diodes (LEDs) and their influence on the degree of conversion (DC) of bulk fill composites. METHODS: A monowave LED (Smartlite Focus, Dentsply) and a polywave LED (Valo Cordless, Ultradent) were characterized using a resin calibrator and a laser beam profile analyzer. Two bulk fill composites, Sonic Fill 2 (SF) containing camphorquinone (CQ) and Tetric EvoCeram Bulk Fill (TEB) containing CQ associated with alternative photoinitiators, were placed in custom-designed molds (n=3) and photoactivated by the monowave or polywave LED with 20 J/cm(2). To map the DC, longitudinal cross sections (0.5 mm thick) from the center of the restoration were evaluated using FT-NIR microscopy. SF and TEB light transmittances (n=3) through 4-mm-thick specimens were evaluated during curing. Data were analyzed using a split-plot analysis of variance and Tukey test (alpha=0.05; beta=0.2). RESULTS: The monowave LED had a radiant emittance of 20 +/- 0.5 J/cm(2) over 420-495 nm, and the polywave LED had an emittance of 15.5 +/- 0.4 J/cm(2) over 420-495 nm and of 4.5 +/- 0.2 J/cm(2) over 380-420 nm. The total radiant exposure at the bottom of TEB was 2.2 +/- 0.2 J/cm(2) with the monowave LED and 1.6 +/- 0.3 J/cm(2) with the polywave LED, and for SF it was 0.4 +/- 0.1 J/cm(2) for both LEDs. There were no differences in the curing profiles produced either by the monowave or the polywave LED (p=0.9), according to the regions under influence of blue and/or violet emission at the same depth. There was no statistical difference in the DC for SF using the monowave or polywave LED at any depth (p=0.29). TEB had a higher DC at up to 2 mm in depth when the polywave LED was used (p<0.004), but no differences were found when starting at 2.5 mm. CONCLUSIONS: Monowave and polywave LEDs emitted nonhomogeneous light beams, but this did not affect the DC homogeneity of bulk fill composites. For composites containing CQ associated with alternative photoinitiators, polywave LEDs had a higher DC, but only at the top part of the restoration; lower wavelength absorption photoinitiators were ineffective in deeper areas. | ||
2016 |
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4. | Oliveira D C R S, Rocha M G, Souza-Júnior E J, Rocha-Maia R, Puppin-Rontani R M, Sinhoreti M A C: The effect of shade and curing mode on cure efficiency of dual-cure resin cements. In: Brazilian Dental Science, vol. 19, no. 3, pp. 59-64, 2016. (Type: Journal Article | Links | Dimensions | PlumX)@article{RN933, | ||
3. | Oliveira D, Rocha M G, Correa I C, Correr A B, Ferracane J L, Sinhoreti M A C: The effect of combining photoinitiator systems on the color and curing profile of resin-based composites. In: Dent Mater, vol. 32, no. 10, pp. 1209-1217, 2016. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN935, OBJECTIVE: To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the color and curing profile of resin-based composites. METHODS: Experimental composites were produced with different CQ and TPO molar concentrations: CQ-only, 3CQ:1TPO, 1CQ:1TPO, 1CQ:3TPO, and TPO-only. Polywave LED was characterized using a beam profiler. Block-shaped samples (5mmx5mmx3mm depth) were cured in a custom-designed mold with a polywave LED positioned to compare the regions exposed to the 420-495nm and 380-420nm LED emittances. To map the cure profile, degree of conversion (DC) of longitudinal cross-sections from each block were evaluated by FT-NIR. Color, light-transmittance and light-absorption during curing were evaluated on specimens 1-3mm thick. Data were analyzed using ANOVA/Tukey's test (alpha=0.05; beta=0.2). RESULTS: Though the polywave LED beam profile was non-uniform, up to a depth of 2mm no differences in DC were found among the composites containing CQ with TPO added up to 50%, regardless of the position under the curing tip. Composites with higher TPO concentration showed a decrease in DC beginning with a depth of 1mm, while composites with higher or similar CQ concentrations did not show decreased DC until a depth of 3mm. Higher TPO concentration reduced initial yellowness and color change after curing; and lower CQ concentration decreased light-absorption at greater depths. SIGNIFICANCE: The combination of CQ with TPO added up to 50% reduced the yellowness and color change of composites after curing without affecting cure efficiency up to a depth of 2mm. | ||
2015 |
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2. | Oliveira D C, Rocha M G, Gatti A, Correr A B, Ferracane J L, Sinhoret M A: Effect of different photoinitiators and reducing agents on cure efficiency and color stability of resin-based composites using different LED wavelengths. In: J Dent, vol. 43, no. 12, pp. 1565-72, 2015. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN934, OBJECTIVES: To evaluate the effect of photoinitiators and reducing agents on cure efficiency and color stability of resin-based composites using different LED wavelengths. METHODS: Model resin-based composites were associated with diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO), phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO) or camphorquinone (CQ) associated with 2-(dimethylamino) ethyl methacrylate (DMAEMA), ethyl 4-(dimethyamino) benzoate (EDMAB) or 4-(N,N-dimethylamino) phenethyl alcohol (DMPOH). A narrow (Smartlite, Dentisply) and a broad spectrum (Bluephase G2, Ivoclar Vivadent) LEDs were used for photo-activation (20 J/cm(2)). Fourier transform infrared spectroscopy (FT-IR) was used to evaluate the cure efficiency for each composite, and CIELab parameters to evaluated color stability (DeltaE00) after aging. The UV-vis absorption spectrophotometric analysis of each photoinitiator and reducing agent was determined. Data were analyzed using two-way ANOVA and Tukey's test for multiple comparisons (alpha=0.05). RESULTS: Higher cure efficiency was found for type-I photoinitiators photo-activated with a broad spectrum light, and for CQ-systems with a narrow band spectrum light, except when combined with an aliphatic amine (DMAEMA). Also, when combined with aromatic amines (EDMAB and DMPOH), similar cure efficiency with both wavelength LEDs was found. TPO had no cure efficiency when light-cured exclusively with a blue narrowband spectrum. CQ-systems presented higher color stability than type-I photoinitiators, especially when combined with DMPOH. CONCLUSIONS: After aging, CQ-based composites became more yellow and BAPO and TPO lighter and less yellow. However, CQ-systems presented higher color stability than type-I photoinitiators, as BAPO- and TPO-, despite their higher cure efficiency when photo-activated with corresponding wavelength range. CLINICAL SIGNIFICANCE: Color matching is initially important, but color change over time will be one of the major reasons for replacing esthetic restorations; despite the less yellowing of these alternative photoinitiators, camphorquinone presented higher color stability. | ||
1. | Oliveira D C, Ayres A P, Rocha M G, Giannini M, Rontani R M P, Ferracane J L, Sinhoreti M A: Effect of Different In Vitro Aging Methods on Color Stability of a Dental Resin-Based Composite Using CIELAB and CIEDE2000 Color-Difference Formulas. In: J Esthet Restor Dent, vol. 27, no. 5, pp. 322-30, 2015. (Type: Journal Article | Abstract | Links | Dimensions | PlumX)@article{RN941, PURPOSE: To evaluate the effect of different in vitro aging methods on color change (CC) of an experimental dental resin-based composite using CIELAB (DeltaEab ) and CIEDE2000 (DeltaE00 ) color-difference formulas. MATERIALS AND METHODS: The CC was evaluated with a spectrophotometer (CM700d, Konica Minolta, Tokyo, Japan) according to the CIE chromatic space. Disk-shaped specimens (Phi = 5 x 1 mm thick) (N = 10) were submitted to different in vitro aging methods: 30 days of water aging (WA); 120 hours of ultraviolet light aging (UVA); or 300 hours of an accelerated artificial aging (AAA) method with cycles of 4 hours of UV-B light exposure and 4 hours of moisture condensation to induce CC. The temperature was standardized at 37 degrees C for all aging methods. CC was evaluated with DeltaEab and DeltaE00 formulas. Differences in individual Lab coordinates were also calculated. Data for the individual color parameters were submitted to one-way analysis of variance and Tukey's test for multiple comparisons (alpha = 0.05). RESULTS: All in vitro aging methods tested induced CC, in the following order: WA: DeltaEab = 0.83 (0.1); DeltaE00 = 1.15 (0.1) < AAA: DeltaEab = 5.64 (0.2); DeltaE00 = 5.01 (0.1) < UVA: DeltaEab = 6.74 (0.2); DeltaE00 = 6.03 (0.4). No changes in L* or a* coordinates were >/=1; the methods with UV aging showed a yellowing effect due a large positive change in b*. CONCLUSIONS: All in vitro aging methods tested induced a CC, but to different extents. Changes in color followed similar trends, but with different absolute values when calculated with the CIELAB and the CIEDE2000 formulas. CLINICAL SIGNIFICANCE: Establishing the efficacy of different artificial aging methods and differences between color change using CIELAB and CIEDE2000 formulas are important to standardize color stability evaluations and facilitate the comparison of outcomes from different studies in the literature. |