Efeito de diferentes aplicações clínicas nas propriedades físico-mecânicas de resinas compostas

Although clinicians use fluoride agents to reduce the occurrence of caries, and surface sealing agents to protect composite restorations, the effects of these agents on composite resins have not yet been investigated. The goal of this study was to determine the effect of different surface applications (fluoride or surface sealant) on resin composites with different organic structures (Siloranes, Sonicfill, 3M Z550, Kalore). In this study, 120 discs and 120 bars made of composite resin were stored in water for three months before being thermally aged by cycling between 5°C and 55°C for 10,000 cycles. The discs were 15 mm in diameter and 1 mm thick; the bars were 25 × 2 × 2 mm. The surface sealant and fluoride were applied to the specimens, and evaluations were performed after 24h. Initial and final calculations were performed for flexural strength, microhardness, roughness, gloss, water sorption, and solubility. Silorane composite showed the lowest water sorption levels (p <0.05) for both initial and aged groups. Silorane and SonicFill composite groups showed the lowest solubility (p <0.05). Both before and after aging, the SonicFill group showed the highest values of flexural strength and microhardness. Silorane showed the highest roughness and lowest gloss values. Lower water sorption and solubility rates were seen on materials fabricated from hydrophobic monomers. High water sorption and solubility degrades the mechanical and surface properties. Fluoridation and surface sealant application can alter the surface properties but do not have any effect on the mechanical properties.RESUMO: Embora os clínicos utilizem agentes de flúor para reduzir a ocorrência de cáries e agentes de vedaçãode superfície para proteger restaurações compostas, os efeitos desses agentes sobre as resinas compostas ainda não foram investigados. O objetivo deste estudo foi determinar o efeito de diferentes aplicações de superfície (fluoreto ou selante de superfície) em resinas compostas com diferentes estruturas orgânicas (Siloranes, Sonicfill, 3M Z550, Kalore). Neste estudo, 120 discos e 120 barras de resina composta foram armazenados em água por três meses antes de serem envelhecidos termicamente por ciclos alternados entre 5 °C e 55 °C por 10.000 ciclos. Os discos tinham 15 mm de diâmetro e 1 mm de espessura; as barras eram 25 × 2 × 2 mm. O selante de superfície e o flúor foram aplicados nos espécimes e as avaliações foram realizadas após 24 horas. Cálculos iniciais e finais foram realizados para resistência à flexão, microdureza, rugosidade, brilho, sorção de água e solubilidade. O compósito de silorano apresentou os menores níveis de sorção de água (p <0,05) para os grupos inicial e envelhecido. Os grupos compostos Silorane e SonicFill apresentaram a menor solubilidade (p <0,05). Tanto antes quanto depois do envelhecimento, o grupo SonicFill apresentou os maiores valores de resistência à flexão e microdureza. Silorane apresentou a maior rugosidade e menores valores de brilho. Baixas taxas de sorção e solubilidade da água foram observadas em materiais fabricados a partir de monômeros hidrofóbicos. A alta sorção e solubilidade da água degrada as propriedades mecânicas e de superfície. A fluoretação e a aplicação de selante de superfície podem alterar as propriedades da superfície, mas não afetam as propriedades mecânicas.Istanbul Universit

Effect of polishing systems on fluoride release and surface roughness of different restorative materials

Secondary caries is an important factor in the replacement of the restorations, and it is thought that fluoride-releasing materials may prevent this problem. Furthermore, the fluoride release of the materials may be increased by polishing process. Available knowledge about the effect of polishing systems (PS) on the fluoride release of materials is limited. Therefore, this study was conducted to evaluate the effect of PS on the fluoride release of fluoride-containing materials. Restorative materials were divided into 6 groups: Fuji IX GP, Fuji II, Dyract XP, Beautifil II, Beautifil-Bulk, and Filtek Ultimate. Each group was also divided into four subgroups: Mylar strip, Sof-Lex Discs, Sof-Lex Diamond, and OneGloss. Fluoride release was determined using a fluoride ion-selective electrode. Surface roughness was evaluated with a profilometer. Two-way repeated measure and one- way ANOVA tests were used for statistical analysis. The initial rapid fluoride release was observed only in Fuji IX. The PS increased the fluoride release of Fuji IX and Fuji II and Dyract XP materials while reducing the fluoride release of resin-based materials. The highest surface roughness values were obtained with OneGloss. Further, a significant relationship between fluoride release and surface roughness was found. The polishing provides an increase in fluoride release, especially in glass-ionomer- based materials. This article revealed that there is a relationship between fluoride release and surface roughness. Proper PS must be chosen according to the material to provide the best clinical benefits in terms of fluoride release and surface roughness

Avaliação das propriedades mecânicas de materiais dentários liberadores de flúor após aplicação múltipla de recarga/descarga de flúor

This study aimed to determine the mechanical properties of fluoride-releasing dental materials after an accelerated fluoride recharge/discharge procedure. Two fluoride-releasing glass ionomer types of cement (Ketac Molar Easymix and IonoStar Molar), a resin-modified glass ionomer (Photac Fil Quick Aplicap), and two compomers (Compoglass F and Glasiosite) were used in this study. A total of 30 rectangular specimens and 30 disk specimens of each material were prepared and placed in distilled/deionized water (n = 5). The amount of fluoride released was analyzed from the materials for 7-day discharge, 1st recharge, 7-day discharge, 2nd recharge, and 7-day discharge, and 3rd recharge. The de/pre- and post-recharge fluoride release were measured using an ion chromatography for 24 days. The flexural strength and microhardness of each group were evaluated. The microhardness of all restorative materials showed no significant change (p > 0.05) over the experimental period. The flexural strength properties of the restorative materials did not change within the time of the study. The study showed that the fluoride release/uptake causes no effect on the mechanical and physical properties of dental materials

Effectiveness of different resin composite materials for repairing noncarious amalgam margin defects

25th IEEE International Conference on Image Processing, ICIP 2018 -- 7 October 2018 through 10 October 2018 -- 143052Objectives: The specific objective of this in vitro study was to determine whether the current flowable resin composites can establish an effective seal in repairing noncarious amalgam margin defects. Material and Methods: A total of 30 freshly extracted caries-free human third molars were used for this investigation. Class I preparations with a standardized 160-µ marginal defect were made by condensing amalgam against a Mylar strip. Accelerated aging and corrosion protocols were then applied to simulate oral conditions. The prepared teeth were randomly divided into five groups (n = 6 per group) according to the repair material employed as follows: (1) no treatment (control); (2) self-adhering flowable resin composite (Vertise Flow); (3) flowable resin composite (Filtek Ultimate Flowable); (4) sonic-activated resin composite (SonicFill); and (5) self-adhesive cement (SmartCem2). Specimens were thermocycled again and then immersed in 5% methylene blue at 37°C for 24 h. For dye-leakage measurements, specimens were sliced longitudinally using a low-speed diamond disk. Results: The results indicated that the flowable resin composite material significantly reduced marginal microleakage compared to the control and SonicFill (P <0.05). Conclusion: Current flowable resin composites were found to be adequate materials for repairing noncarious amalgam margin defects

Effectiveness of remineralization agents on the prevention of dental bleaching induced sensitivity: A randomized clinical trial

Objectives This study aims to compare the use of different remineralization agents before in-office bleaching for decreasing bleaching induced sensitivity. Methods A total of 64 volunteers were randomly divided into four groups. Before undergoing in-office bleaching with 38% hydrogen peroxide gel (three applications of 15 min each, one session), clinicians applied a placebo gel (control group), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), neutral sodium fluoride gel (NSF) or nano-hydroxyapatite solution (n-HAP) on all buccal surfaces of teeth. The gel was left undisturbed for 4 min. The efficacy of tooth whitening was assessed by determining the colour change using SGU. Patients recorded their tooth sensitivities on the VAS scale. Kruskal-Wallis test followed by Mann-Whitney U test was used to compare changes in tooth colour and intensity of tooth sensitivity between groups. Results Overall, there was no significant difference in shade change between the groups. Control and CPP-ACP groups showed significantly higher rates of hypersensitivity than NSF and the n-HAP group (p < 0.05). Conclusions: The use of a remineralization agent (n-HAP/NSF) before in-office bleaching did not affect the bleaching efficacy but did reduce tooth sensitivity. The before bleaching treatment use of an n-HAP solution can be suitable for reducing bleaching born sensitivity as well as commonly used NSF remineralizing gel before in-office tooth bleaching can reduce tooth sensitivity, the most common side effect associated with this procedure

Mechanical properties and repair bond strength of polymer-based CAD/CAM restorative materials

Information on the mechanical properties and repairability of computer-aided design/computer-aided manufacturing (CAD/CAM) blocks is scarce. Five CAD/CAM blocks with similar indications were evaluated, including four resin nanoceramics, one polymer-infiltrated ceramic network (PICN), and one feldspathic ceramic. CAD/CAM blocks were sectioned into 4 mm x 1.2 mm x 13 mm bars for flexural strength (FS), and 4 mm thick blocks were prepared for elastic modulus (EM), nanohardness (NH), and microshear bond strength (mu SBS) testing. FS of the CAD/CAM blocks was determined using a three-point bending test, whereas EM and NH values were measured using a nanoindenter. The reparability of the tested block materials was determined by the mu SBS test. One-way ANOVA was conducted for FS, EM, NH, and mu SBS followed by Tukey's pairwise comparison (alpha < 0.05). FS ranged from 115 to 207 MPa, EM from 8.21 to 44 GPa, NH from 0.76 to 7.24, and mu SBS from 24.9 to 30.6 MPa. The findings of the present study revealed that resin nanoceramic blocks exhibited higher FS values than PICN and feldspathic ceramic, and they have acceptable mechanical properties for the fabrication of single-unit restorations according to the ISO 6872:2008. Furthermore, all CAD/CAM blocks tested can be successfully repaired regarding their recommended repair protocol

The prevalence and distribution of the dental anomalies in the Turkish population

Introduction: The incidence of developmental dental anomalies can provide valuable information. The aim of this study is to investigate the prevalence and distribution of dental anomalies in the Turkish population. Material and Methods: Totally 2203 patients who came to university hospital were examined clinically and radiographically for 10 dental anomalies: rotation, diastema, hypodontia, hyperdontia, microdontia, macrodontia, dilaceration, talon cusp, gemination and ectopia. Descriptive characteristics of these dental anomalies, including gender and regions of the jaw, were recorded. The data were analyzed with Chi-square test and Yates continuity correction. Results: In 1517 patients (68.9%), tooth anomaly was detected. Rotation was found in 58.4% of patients, significantly lower in the molar region than in the anterior and premolar regions (P 0.05). Gemination was seen in only one anterior tooth and macrodontia in only one premolar tooth. Discussion and Conclusion: Rotation is the most common dental anomaly in Turkish population, followed by diastema. Knowledge of the prevalence of anomalies may help clinicians to the detection of these anomalies at early stages

Effect of polishing systems on fluoride release and surface roughness of different restorative materials

Secondary caries is an important factor in the replacement of the restorations, and it is thought that fluoride-releasing materials may prevent this problem. Furthermore, the fluoride release of the materials may be increased by polishing process. Available knowledge about the effect of polishing systems (PS) on the fluoride release of materials is limited. Therefore, this study was conducted to evaluate the effect of PS on the fluoride release of fluoride-containing materials. Restorative materials were divided into 6 groups: Fuji IX GP, Fuji II, Dyract XP, Beautifil II, Beautifil-Bulk, and Filtek Ultimate. Each group was also divided into four subgroups: Mylar strip, Sof-Lex Discs, Sof-Lex Diamond, and OneGloss. Fluoride release was determined using a fluoride ion-selective electrode. Surface roughness was evaluated with a profilometer. Two-way repeated measure and one-way ANOVA tests were used for statistical analysis. The initial rapid fluoride release was observed only in Fuji IX. The PS increased the fluoride release of Fuji IX and Fuji II and Dyract XP materials while reducing the fluoride release of resin-based materials. The highest surface roughness values were obtained with OneGloss. Further, a significant relationship between fluoride release and surface roughness was found. The polishing provides an increase in fluoride release, especially in glass-ionomer-based materials. This article revealed that there is a relationship between fluoride release and surface roughness. Proper PS must be chosen according to the material to provide the best clinical benefits in terms of fluoride release and surface roughness.La caries secundaria es un factor importante para el reemplazo de restauraciones y se considera que los materiales que liberan flúor pueden prevenir este problema. Además, la liberación de fluoruro de estos materiales podría incrementarse mediante el proceso de pulido. El conocimiento disponible sobre el efecto de los sistemas de pulido (SP) en la liberación de fluoruro de los materiales es limitado. Por lo tanto, este estudio se realizó para evaluar el efecto de los SP sobre la liberación de fluoruro de materiales que contienen fluoruro. Los materiales de restauración se dividieron en 6 grupos: Fuji IX GP, Fuji II, Dyract XP, Beautifil II, Beautifil-Bulk y Filtek Ultimate. Cada grupo también se dividió en cuatro subgrupos: Banda Mylar, Discos Sof-Lex, Sof-Lex Diamond y OneGloss. La liberación de fluoruro se determinó usando un electrodo selectivo de iones fluoruro. La rugosidad de la superficie se evaluó con un perfilómetro. Se utilizaron medidas repetidas bidireccionales y pruebas ANOVA de una vía para el análisis estadístico. La liberación inicial rápida de fluoruro se observó solo en Fuji IX. El SP aumentó la liberación de fluoruro de los materiales Fuji IX y Fuji II y Dyract XP al tiempo que redujo la liberación de fluoruro de los materiales a base de resina. Los valores más altos de rugosidad de la superficie se obtuvieron con OneGloss. Además, se encontró una relación significativa entre la liberación de fluoruro y la rugosidad de la superficie. El pulido proporciona un aumento en la liberación de fluoruro, especialmente en materiales a base de ionómero de vidrio. Este artículo reveló que existe una relación entre la liberación de fluoruro y la rugosidad de la superficie. El SP adecuado debe elegirse de acuerdo con el material para proporcionar los mejores beneficios clínicos en términos de liberación de fluoruro y rugosidad de la superficie

Effect of surface treatments and universal adhesive application on the microshear bond strength of CAD/CAM materials

PURPOSE. The aim of this study was to evaluate the microshear bond strength (mu SBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols. MATERIALS AND METHODS. Four different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, mu SBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests. RESULTS. The findings revealed that silane application yielded higher mu SBS values (P<.05). All surface treatments were showed a significant increase in mu SBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05). CONCLUSION. Surface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases