Ultrastructural investigation of the effect of toothpastes containing different remineralizing agents on demineralized enamel.

OBJECTIVE: The present study aimed to evaluate the effect of remineralizing agents on demineralized enamel intended for use as fluoride substitutes or supplements for oral hygiene applications. METHODOLOGY: Enamel samples were obtained from 30 bovine teeth. The enamel blocks were stored in 20 mL of demineralization solution for 72 h. They were then brushed with the following toothpaste for the remineralization protocol: NaF, NaF/SnF2 combination, NovaMin, or nano-hydroxyapatite. SEM/EDX examinations and microhardness measurements of the samples were performed to investigate the remineralization efficacy of the studied toothpaste. One-way analysis of variance (ANOVA) with post hoc Tukey's HSD test was used to analyze the change in microhardness values in different remineralization protocols (p < 0.05). RESULTS: Differences in the mean remineralization (%RP) and hardness recovery (%HR) were determined between the groups (p < 0.05). Groups 1 and 4 showed significant differences in %RP (p < 0.05). In the SEM/EDX examinations, the samples treated with n-HAp showed an accumulation of crystal deposits on the enamel surface, although at a lower density than those treated with NaF and NaF/SnF2 combination. CONCLUSION: The remineralization strategy in toothpaste plays an important role in enamel remineralization. NovaMin-containing toothpaste showed positive effects on the enamel surface with better Ca/P ratio. Toothpastes containing n-HAp triggered less change in the increase of microhardness values compared to other toothpastes. The use of SnF2 in toothpaste in combination with NaF significantly increased the binding of fluoride to demineralized enamel compared to toothpaste containing NaF alone.

Digitalization era of dental education: A systematic review.

BACKGROUND: Dental education is taking its share of the digitalization of the world. Therefore, it is of value to assess the use of the digital dental education system, especially in the undergraduate period. OBJECTIVES: This systematic review concisely evaluated the use of augmented and virtual reality in preclinical dental education. MATERIAL AND METHODS: The PICOS (Population, Intervention, Comparison, Outcome, and Study design) search strategy was used with the keywords 'e-learning', 'virtual reality' and 'preclinic simulation' to search the PubMed, PubMed Central, Web of Science, and Scopus databases. RESULTS: A total of 1,774 articles were found, and 45 articles were reviewed. The level of bias in the studies was also calculated. The studies were divided into 3 main groups: computer-assisted learning (C-AL); augmented reality-assisted learning (AR-AL); and virtual reality-assisted learning (VR-AL). Augmented and virtual reality are steadily evolving, and are increasingly being used in education and healthcare. CONCLUSIONS: The evaluated technological applications enable the visualization of medical information and provide clear feedback during the learning process with increased security and reliability; thus, digital simulation systems can be used to enhance students' abilities in dentistry.

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.

Evaluation of mechanical properties of fluoride-releasing dental materials after multiple fluoride recharge/discharge application / 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.

Este estudo teve como objetivo determinar as propriedades mecânicas de materiais dentários liberadores de flúor após um procedimento acelerado de recarga/descarga de flúor. Dois tipos de cimento de ionômero de vidro liberador de flúor (Ketac Molar Easymix e IonoStar Molar), um ionômero de vidro modificado por resina (Photac Fil Quick Aplicap) e dois compômeros (Compoglass F e Glasiosite) foram utilizados neste estudo. Um total de 30 amostras retangulares e 30 amostras de disco de cada material foram preparadas e colocadas em água destilada/deionizada (n = 5). A quantidade de fluoreto liberado foi analisada a partir dos materiais para descarga em 7 dias, 1ª recarga, descarga em 7 dias, 2ª recarga e descarga em 7 dias e 3ª recarga. A liberação de fluoreto pré e pós-recarga foi medida usando uma cromatografia de íons por 24 dias. A resistência à flexão e a microdureza de cada grupo foram avaliadas. A microdureza de todos os materiais restauradores não apresentou alteração significativa (p > 0,05) durante o período experimental. As propriedades de resistência à flexão dos materiais restauradores não mudaram no período do estudo. O estudo mostrou que a liberação/captação de flúor não afeta as propriedades mecânicas e físicas dos materiais dentários.

Effect of Polishing Systems on Fluoride Release and Surface Roughness of Different Restorative Materials / El efecto de los sistemas de pulido en la liberación de flúor y rugosidad de diferentes materiales restauradores

ABSTRACT 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.

RESUMEN 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 (µSBS) 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, µSBS 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 µSBS values (P<.05). All surface treatments were showed a significant increase in µSBS 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.

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

OBJECTIVES: 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.

Effect of different clinical applications on physico-mechanical properties of composite resins / 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.

Embora os clínicos utilizem agentes de flúor para reduzir a ocorrência de cáries e agentes de vedação de 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.

Three-year randomized clinical evaluation of a low-shrinkage silorane-based resin composite in non-carious cervical lesions.

OBJECTIVE: The clinical suitability of low-shrinkage resin composites for class V cavities has not been investigated in vivo. The purpose of this double-blind randomized clinical trial was to compare the clinical performances of low-shrinkage resin composite Filtek silorane and nanoceramic resin composite Ceram X mono in non-carious cervical lesions (NCCLs) over 36 months. MATERIALS AND METHODS: Two calibrated operators restored 144 NCCLs in 24 patients by using Filtek silorane with silorane system adhesive (FS/SSA) and Ceram X mono with Clearfil SE (CXM/CSE) or XP bond (CXM/XPB). Then, two blinded, calibrated evaluators assessed the restorations at the baseline and 6, 12, 24, and 36 months thereafter by using the modified US Public Health Service criteria. Data were analyzed with the Freidman and Wilcoxon signed-rank tests at a significance level of 5 % (P < 0.05). RESULTS: No restoration was associated with postoperative sensitivity or secondary caries. Further, no group showed significant changes until 12 months. The retention rates of the FS/SSA (97.5 %), CXM/CSE (97.5 %), and CXM/XPB (92.31 %) restorations did not differ significantly (P > 0.05). Six (4 CXM/XPB, 1 FS/SSA, and 1 CXM/CSE) of the 121 restorations evaluated at 36 months were completely lost. However, no significant intergroup differences were observed in the other evaluation criteria. CONCLUSION: The 3-year clinical performances of the restorative materials in NCCLs were not significantly different. CLINICAL RELEVANCE: Filtek silorane is suitable for restoring NCCLs.

The effects of glass ionomer and flowable composite liners on the fracture resistance of open-sandwich class II restorations.

This in vitro study aimed to investigate the effects of glass-ionomer and flowable composite liners on the fracture resistance of Class II amalgam and composite restorations. Group 1 cavities were restored with amalgam and Group 4 cavities with nanofill composite after the application of a dentin-bonding agent. For the remaining groups, light-cured-glass-ionomer liner was used in a gingival floor proximal box (Groups 2, 5) or flowable composite was used as a liner (Groups 3, 6), the remainder of the cavity was restored with amalgam (Groups 2, 3) or composite (Groups 5, 6). The restorations were loaded in compression to failure. The data was analyzed using Tukey's multiple comparison test. The fracture resistance was significantly higher (p<0.05) in Group 3 than in all other groups, except Group 2 (p>0.05). Flowable composite, glass-ionomer liners increased the fracture resistance of open-sandwich Class II amalgam restorations.

Randomized controlled trial of the 2-year clinical performance of a silorane-based resin composite in class 1 posterior restorations.

PURPOSE: To compare the 2-year clinical performance of a silorane-based resin composite with that of an established nanoceramic resin composite for class 1 posterior restorations. METHODS: In this randomized controlled study, 100 class 1 molar cavities were prepared in 50 subjects. Each subject received a restoration with Filtek Silorane and Ceram.X Duo in different quadrants. The restorations were evaluated using the modified USPHS criteria at baseline and 6, 12, and 24 months. Parametric changes over the 2-year period were assessed with the Friedman test. The baseline and recall scores were compared by using the Wilcoxon signed-rank test (P < 0.05). RESULTS: No subject developed secondary caries or postoperative sensitivity. Further, the resin composites showed no significant differences in all the evaluated parameters over 2 years (P > 0.05). At 2 years, four Filtek Silorane and seven Ceram.X Duo restorations had Bravo scores for anatomic form, marginal adaptation, and surface texture (P < 0.05); however, these changes were mainly the effect of scoring shifts from Alfa to Bravo. Overall, both materials showed good clinical results with predominantly Alfa scores.