Comparative analysis of shear bond strength of MTA and Theracal PT with different restorative materials.

BACKGROUND: This study aimed to compare the in vitro shear bond strength (SBS) of mineral trioxide aggregate (MTA) and dual-cured, resin-modified calcium silicate material (Theracal PT) to composite resin, compomer, and bulk-fill composite, and to evaluate the bond failure mode under a stereomicroscope. METHODS: Ninety acrylic specimens, each with a 4 mm diameter and 2 mm height central hole, were prepared. These specimens were randomly divided into two groups based on the capping materials: MTA and Theracal PT. Each group was further subdivided into three subgroups (n = 15) according to the restorative materials: composite resin, compomer, and bulk-fill composite. The specimens were then subjected to shear testing using a universal testing machine at a crosshead speed of 1 mm/min. Post-test, the fracture locations were examined using a stereomicroscope. Data were analyzed using a two-way analysis of variance (ANOVA) and the Tukey test. RESULTS: The SBS values for the Theracal PT group were significantly higher than those for the MTA group (p < 0.001). Within the MTA groups, no significant differences were observed in SBS values across the different restorative materials. However, a significant difference was found between the mean SBS values of the Theracal PT + composite resin group and the Theracal PT + compomer group (p < 0.001). CONCLUSIONS: Theracal PT shows promise in dentistry due to its superior bond strength. Given its bond values, Theracal PT appears capable of forming durable and long-lasting restorations by establishing reliable bonds with various restorative materials commonly used in dentistry.

Effect of Bonding Agents on the Shear Bond Strength of Tooth-colored Restorative Materials to Dentin: An In Vitro Study.

AIM: The aim of the study is to determine the difference in the shear bond strengths to dentin among dental composite (Filtek Z350®, 3M), compomer (Dyract Flow®, Dentsply) and Giomer (Beautifil®, Shofu) with 3MTM Single BondTM Universal Adhesive (SBU) (7th generation, self-etch, single solution adhesive) and AdperTM Single Bond 2 Adhesive (ASB) (5th generation, total-etch, two solution adhesive). MATERIALS AND METHODS: Sixty extracted human permanent teeth were collected, cleansed of debris, and placed in distilled water. The samples were segregated into two groups depicting the two bonding agents-AdperTM (ASB) and 3MTM Single Bond Universal (SBU) and sub-grouped into three groups depicting the three restorative materials (Composite, Giomer, and Compomer) used. Groups were respresented as follows: Group I-ASB + Composite; Group II-ASB + Giomer; Group III-ASB + Compomer; Group IV-SBU + Giomer; Group V-SBU + Compomer; Group VI-SBU + Composite. After applying the bonding agent as per the manufacturer's instructions, following which the restorative material was placed. A Universal Testing Machine (Instron 3366, UK) was employed to estimate the shear bond strength of the individual restorative material and shear bond strengths were calculated. RESULTS: Composite bonded with SBU (group VI) displayed the greatest shear strength (11.16 ± 4.22 MPa). Moreover, Giomers and flowable compomers displayed better bond strengths with ASB compared with their SBU-bonded counterparts. CONCLUSION: These results mark the importance of careful material selection in clinical practice and the bonding agent used to achieve optimal bond strength and enhance the clinical longevity and durability of dental restorations. CLINICAL SIGNIFICANCE: From a clinical perspective, to avoid a compressive or a shear failure, it would be preferrable to use a direct composite restorative material with SBU (Single bond universal adhesive, 7th generation) to achieve maximum bond strength. How to cite this article: Kuchibhotla N, Sathyamoorthy H, Balakrishnan S, et al. Effect of Bonding Agents on the Shear Bond Strength of Tooth-colored Restorative Materials to Dentin: An In Vitro Study. J Contemp Dent Pract 2024;25(3):245-249.

Residual Monomer Release after the Polymerization of Different-Colored Flowable Compomer.

BACKGROUND: Compomers are restorative materials commonly used in pediatric dentistry. It is important to investigate the monomer release of materials used especially in pediatric patients. The aim of this study was to evaluate the residual monomer released from different-colored flowable compomers at five polymerization times. MATERIALS AND METHODS: Three experimental groups were formed: Group 1: pink flowable compomer (Twinky Star, VOCO, Germany), Group 2: blue flowable compomer (Twinky Star, VOCO), Group 3: white flowable compomer, A2 color of Dyract XP (Dentslpy DeTrey, Konstanz, Germany). For each group, samples were prepared using standard cylindrical Teflon molds (n = 10), and the compomers were cured using a light-emitting diode (LED) source in accordance with the manufacturer's recommendations. During each time period, the number of residual monomers: bisphenol-A glycidyl methacrylate (bis-GMA), urethane dimethacrylate (UDMA), hydroxyethyl methacrylate (HEMA), and triethylene glycol dimethacrylate (TEGDMA) were determined with high-performance liquid chromatography (HPLC). All data were analyzed statistically. RESULTS: In all groups, the amount of residual monomers increased after 1-h release periods (P < 0.05). For 2 weeks, the total residual monomers released were determined at most in Group 3 and at least in Group 1. However, there was no significant difference between the groups in terms of released amounts of monomers (P > 0.05). CONCLUSIONS: According to the study, when the total amount of residual monomer released from all groups was compared, no difference was found and it was observed that none of them exceeded the toxic dose. Flowable colored compomers can be used as safely as white compomers in pediatric dentistry.

Effect of topical fluoride applications on residual monomer release from resin-based restorative materials.

BACKGROUND: The effects of topical fluoride applications on the release of monomer ingredients from resin-based dental materials by immersion in various extraction solutions are unclear. The aim of this study was to determine the effect of topical fluorides (APF and NaF) on the elution of residual monomers (Bis-GMA, TEGDMA, UDMA, and HEMA) from resin-based materials. METHODS: Ninety specimens were prepared, 30 bulk-fill composite resin, 30 nanohybrid universal composite resin, and 30 polyacid-modified composite resin (compomer). These were randomly divided into three groups based on fluoride application procedures. Each specimen was kept in 75% ethanol solution, and residual monomers released from materials were analyzed using high-performance liquid chromatography (HPLC) after 10 min, 1 h, 24 h, and 30 days. The groups were compared using the Mann Whitney U and Kruskal Wallis tests. Measurements were analyzed using the Friedman and Wilcoxon signed-rank tests. RESULTS: Fluoride applications generally had no considerable effect on the amount of residual monomer released from resin-based restorative materials. The amount of monomer release after topical APF application was similar to the release in the control group and was lower than the release in the NaF group. The release of monomers from the resin-based material used in the study did not approach toxic levels at the applied time intervals. The compomer released lower amounts of monomer than other resin-based materials. CONCLUSIONS: Fluoride applications do not increase monomer release from resin-based restorative materials. However, compomers should be employed by clinicians due to their lower monomer release compared to other resin restorative materials. The release of monomers from all the resin-based materials did not approach toxic levels at the applied time intervals.

The cytotoxic and oxidative effects of restorative materials in cultured human gingival fibroblasts.

The aim of this study was to evaluate the cytotoxic and oxidative effects of the most commonly used dental restorative materials on human gingival fibroblast cells (HGFCs). HGFCs were obtained from healthy individuals. The tested restorative materials were a microhybrid resin based composite, a compomer resin, a glass ionomer cement, and an amalgam alloy. One hundred eight cylindirical samples, 10 mm in diameter and 2 mm in height, were prepared according to ISO 10993-12:2002 specifications (n = 9 in the tested subgroups). Freshly prepared and aged samples in artificial saliva at 37 °C (7 and 21 d) were placed into well plates and incubated. Wells without dental materials were constituted as the control group. After 72 h incubation period, cytotoxicity was determined using the neutral red (NR) assay. Oxidative alterations were assessed using total antioxidant capacity (TAC) and total oxidant status (TOS) assay kits. Data were analyzed using the ANOVA and LSD post hoc tests. All tested materials led to significant decreases in the cell viability rates (33-73%) compared to the control group. Glass ionomer and resin composite were found to be more cytotoxic than amalgam alloy and compomer. The highest TAC level was observed in glass ionomer after seven-day aging and these changes prevented an increase in TOS levels. Increases in TAC levels after seven-day aging in all groups exhibited significant differences with freshly prepared samples (p < 0.05). In all material groups, TOS levels of freshly prepared samples differed statistically and significantly from samples aged for 7 and 21 d (p < 0.05). The data obtained suggested that all the tested materials exhibited cytotoxic and pro-oxidant features. Freshly prepared samples caused higher TOS levels. However, oxidant status induced by materials decreased over time.

The evaluation of microleakage and fluoride release of different types of glass ionomer cements.

BACKGROUND: The aim of this study was to evaluate six different glass ionomer cement (GIC)-based restorative materials through comparisons of microleakage and fluoride release. MATERIALS AND METHODS: For microleakage, 30 teeth were randomly separated into 6 groups of 5: Group 1 (Dyract: compomer), Group 2 (Freedom: compomer), Group 3 (Equia: high-viscosity glass ionomer cements), Group 4 (Fuji IX: resin-modified glass ionomer cement), Group 5 (Ketac Molar: traditional glass ionomer cement [TGIC]) and Group 6 (Voco: TGIC). For fluoride release of six different GIC-based restorative materials, standard samples were prepared of 4 mm thickness and 7 mm diameter. A total of 60 samples were obtained as 10 samples from each group. The analyses were made using a Thermo Orion 720 A+ ionometer with the Orion fluoride electrode. At the end of 24 h, 72 h, 7 days, 14 days, and 30 days, the electrode was placed into the dish containing the sample, distilled water, and TISAB II; a reading was taken; and the value shown on the screen was recorded. RESULTS: For microleakage, a statistically significant difference was determined between the groups in respect of the occlusal variable (P < 0.05), no statistically significant gingival variable (P > 0.05). About fluoride release: According to the repeated measures variance analysis results, the difference between the groups, and between the time-group interaction and according to time, was found to be statistically significant (P < 0.05). CONCLUSIONS: In terms of microleakage, it was concluded that all materials could be used in clinical applications. The Equia high-viscosity glass ionomer cements (HVGIC) was determined to be the material with the highest fluoride release value.

Microtensile Bond Strength of Polyacid-modified Composite Resin to Irradiated Primary Molars.

AIM: This study evaluated the influence of various doses of radiotherapy on the microtensile bond strength (pTBS) of compomer resin to dentin and enamel in primary molars. MATERIALS AND METHODS: Thirty-five intact primary molars were collected and divided into seven groups. Teeth were irradiated with doses from 10 to 60 Gy, except for the control group. Compomer restorations were performed, and enamel-compomer resin beams and dentin-compomer resin beams were tested at a crosshead speed of 1 mm/min. RESULTS: No statistically significant difference was found between the irradiated tooth enamel and the control group (F = 1.1468; p = 0.194). However, statistically significant differences were evident among the dentin groups (F = 11.050; p < 0.001). CONCLUSION: Radiation may not cause a significant difference in the pTBS of compomer resin to primary tooth enamel, but appears to dose dependently decrease its bond strength to primary tooth dentin. CLINICAL SIGNIFICANCE: Radiotherapy may affect the success rate of compomer fillings in primary teeth, especially in deeper cavities with exposed dentin.

A comprehensive evaluation of application of light-cured colored compomer for deciduous teeth.

Twinky Star colored compomer produced by VOCO GmbH is a new type of filling material designed with seven different colors. Previous studies have shown that using the colored filling material can induce children’s curiosity and increase the acceptance for dental treatment. However, few studies have been conducted to evaluate it. Hence, the present study was designed to assess the mechanical and adhesive properties of this new compomer, examine its biological safety, and evaluate the effects of its clinical application on children’s adherence to dental treatment and the subsequent therapeutic outcomes. We found that Twinky Star compomer has a high compressive strength, good biaxial flexural strength, low wear rate, and good adhesive properties, and had little in vitro cytotoxic effects and did not cause apparent hemolysis in vivo. Finally, application of the compomer helped to improve children’s acceptance of treatment without affecting the subsequent therapeutic outcomes in the follow-up examinations. To summarize, the findings suggest that Twinky Star compomer meets the performance requirements for dental fillings, and can be recommended for future clinical application.

Color stability of nanohybrid resin-based composites, ormocers and compomers.

OBJECTIVE: The aim of this study is to evaluate the color stability of two nanohybrid resin-based composites, two organic modified ceramic resin composites (ormocers) and a compomer, following their immersion during 4 weeks in four usual drinks. MATERIAL AND METHODS: Forty discs of each of the following materials were prepared: GrandioSO (GR), Esthet X (EX), Dyract EXTRA (DY), Ceram X duo (CX), and Admira Fusion (AD). The discs were polished and stored in distilled water during 24 h at 37 °C. Color according to the CIEL*a*b* scale was recoded. Ten randomly selected samples of each material were immersed in red wine (RW), coffee (CF), cola (CK), and distilled water (DW). The color was recorded after 1, 7, 21 and 28 days of immersion. The ΔE values between the baseline color and each of the study timepoints were calculated. The data were analyzed based on the Kruskal-Wallis test, Wilcoxon test, and Mann-Whitney U test. RESULTS: After 1 day of immersion, all the materials showed ΔE > 3.3, except EX, CF, and CX in CK. RD was the most staining beverage (ΔE 15.36 to 31.09). EX and CX were significantly less stained than the rest of the materials (p < 0.05). CONCLUSIONS: All the staining solutions produced darkening beyond clinically acceptable limits. EX and CX were the materials who experimented less staining, followed by GD. AD and DY were the materials more stained. RW was the drink that produced more staining, followed by CF and CK. CLINICAL RELEVANCE: After 24 h of immersion in all the solutions, equivalent to 1 month of exposure in the mouth, the evaluated materials showed clinically unacceptable ΔE values.

Silorane, ormocer, methacrylate and compomer long-term staining susceptibility using ΔE and ΔE 00 colour-difference formulas.

The aim of this study was to evaluate the staining susceptibility of a silorane (Filtek Silorane), an ormocer (Ceram X Duo), a methacrylate (Tetric EvoCeram) and a compomer (Dyract) exposed on the long term to various staining agents by using ΔE and ΔE 00 colour-difference formulas. Thirty-six disc-shaped specimens were made of each of the four chemically different materials, randomly divided in six groups (n = 6) and immersed in five staining solutions (red wine, juice, coke, tea and coffee) or stored dry (control) in an incubator at 37 °C for 99 days. Spectrophotometric measurements by means of a spectrophotometer (Spectroshade Handy Dental, MHT) were repeated over a white (L* = 92.6, a* = -1.2, b* = 2.9) and black (L* = 1.6, a* = 1.2, b* = -1.0) background made of plasticized paper, in order to determine the colour changes according to ΔE, ΔE 00 and translucency formulas. Statistical analysis was performed by means of factorial Anova, Fisher's LSD test (post hoc) and a Spearman rank correlation between ΔE and ΔE 00. When analysed over a white background, mean ΔE 00 values were highly significantly different and varied from 0.8 (Ceram X Duo/air) to 20.9 (Ceram X Duo/red wine). When analysed over a black background, mean ΔE 00 values were highly significantly different and varied from 1.0 (Ceram X Duo and Tetric/air) to 25.2 (Ceram X Duo/red wine). Differences in translucency varied from 0.3 (Ceram X Duo/air) to 21.1 (Ceram X Duo/juice). The correlation between ΔE and ΔE 00 over a white background was 0.9928, while over a black background, it was 0.9886.

Effect of a third-generation LED LCU on microhardness of tooth-colored restorative materials.

OBJECTIVE: To assess the effects of different modes of a third-generation light-curing unit (LCU) (VALO) on the microhardness of restorative materials. DESIGN: A microhybrid composite resin (Filtek(™) Z550), a giomer (Beautifil II), a compomer (Dyract eXtra) and a RMGIC (Photac(™) Fil) were used in the study. Three different modes of VALO were tested and a second-generation LCU (Elipar S10) was used as a control. The microhardness (VHN) was measured using a Vickers Hardness tester. Data were analyzed using two-way anova and post hoc Tukey's test (P < 0.05). RESULTS: The Filtek Z550 group had the highest VHN values followed by Photac Fil, Beautifil II and the Dyract eXtra at both top and bottom surfaces, however the difference between Filtek Z550 and Photac Fil was not statistically significant for the bottom surfaces (P > 0.05). Of the different curing protocols tested, the VALO LCU in Mode 3 resulted in the lowest VHN values at both top and bottom surfaces (P < 0.05). CONCLUSION: Based on the results of this study, it can be concluded that the high-power mode of the VALO LCU can be recommended for clinical applications especially in pediatric patients, as it can shorten the time required to adequately polymerize resin-based tooth-colored restorative materials.

Clinical performance of aesthetic restorative materials in primary teeth according to the FDI criteria.

AIM: The purpose of this study is to evaluate the clinical performance of three different restorative materials in primary teeth according to the FDI criteria. MATERIALS AND METHODS: Resin-modified glass ionomer cement, compomer and composite resin restorations (n=93) were made in 31 patients. The restorations were clinically evaluated at baseline, 6th, 12th and 18th month with the FDI criteria. RESULTS: The cumulative survival rate after 18 months was found to be 90.3% for resin modified glass ionomer cement restorations, 100% for compomer restorations and 80.6% for composite resin restorations. Statistically significant increase in surface roughness, colour mismatch, anatomic form loss and marginal deterioration were detected in resin- modified glass ionomer group (p<0.05). The most frequent reason for restoration failure in composite resin group was restoration fractures. CONCLUSIONS: The resin-modified glass ionomer restorations necessitates close follow-up because of the risk of increase in surface roughness, changes in colour and loss in anatomic form and marginal adaptation. The clinical performance of compomer restorations is superior to resin-modified glass ionomer and composite resin restorations in primary teeth.

A Retrospective Study of the 3-Year Survival Rate of Resin-Modified Glass-Ionomer Cement Class II Restorations in Primary Molars.

OBJECTIVE: To determine the three-year survival rate of Class II resin-modified glass-ionomer cement (RMGIC), Vitremer, restorations in primary molars and to compare these results with measurements of survival of Class II restorations of standard restorative materials. STUDY DESIGN: Data on Class II restorations placed in primary molars during a six-year period were collected through a chart review and radiographic evaluation in the office of a board-certified pediatric dentist. A radiograph showing that the restoration was intact was required at least 3 years after placement to qualify as successful. If no radiograph existed, the restoration was excluded. If the restoration was not found to be intact radiographically or was charted as having been replaced before three years it was recorded as a failure. The results of this study were then compared to other standard restorative materials using normalized annual failure rates. RESULTS: Of the 1,231 Class II resinmodified glass-ionomer cement restorations placed over six years 427 met the inclusion criteria. There was a 97.42% survival rate for a 3-year period equivalent to an annual failure rate of 0.86%. CONCLUSIONS: A novel approach comparing materials showed that in this study Vitremer compared very favorably to previously published success rates of other standard restorative materials (amalgam, composite, stainless steel crown, compomer) and other RMGIC studies.

Meta-Analysis of the Influence of Bonding Parameters on the Clinical Outcome of Tooth-colored Cervical Restorations.

PURPOSE: To meta-analyze the literature on the clinical performance of Class V restorations to assess the factors that influence retention, marginal integrity, and marginal discoloration of cervical lesions restored with composite resins, glass-ionomer-cement-based materials [glass-ionomer cement (GIC) and resin-modified glass ionomers (RMGICs)], and polyacid-modified resin composites (PMRC). MATERIALS AND METHODS: The English literature was searched (MEDLINE and SCOPUS) for prospective clinical trials on cervical restorations with an observation period of at least 18 months. The studies had to report about retention, marginal discoloration, marginal integrity, and marginal caries and include a description of the operative technique (beveling of enamel, roughening of dentin, type of isolation). Eighty-one studies involving 185 experiments for 47 adhesives matched the inclusion criteria. The statistical analysis was carried out by using the following linear mixed model: log (-log (Y /100)) = ß + α log(T ) + error with ß = log(λ), where ß is a summary measure of the non-linear deterioration occurring in each experiment, including a random study effect. RESULTS: On average, 12.3% of the cervical restorations were lost, 27.9% exhibited marginal discoloration, and 34.6% exhibited deterioration of marginal integrity after 5 years. The calculation of the clinical index was 17.4% of failures after 5 years and 32.3% after 8 years. A higher variability was found for retention loss and marginal discoloration. Hardly any secondary caries lesions were detected, even in the experiments with a follow-up time longer than 8 years. Restorations placed using rubber-dam in teeth whose dentin was roughened showed a statistically significantly higher retention rate than those placed in teeth with unprepared dentin or without rubber-dam (p < 0.05). However, enamel beveling had no influence on any of the examined variables. Significant differences were found between pairs of adhesive systems and also between pairs of classes of adhesive systems. One-step self-etching had a significantly worse clinically index than two-step self-etching and three-step etch-and-rinse (p = 0.026 and p = 0.002, respectively). CONCLUSION: The clinical performance is significantly influenced by the type of adhesive system and/or the adhesive class to which the system belongs. Whether the dentin/enamel is roughened or not and whether rubberdam isolation is used or not also significantly influenced the clinical performance. Composite resin restorations placed with two-step self-etching and three-step etch-and-rinse adhesive systems should be preferred over onestep self-etching adhesive systems, GIC-based materials, and PMRCs.

Evaluation of a modified Pulpotec endodontic approach on necrotic primary molars: a one-year follow-up.

AIM: The aim of this study was to evaluate the effectiveness of a Pulpotec modified endodontic approach on primary molars presenting necrotic pulp and furcation bone loss in a cohort of healthy children. MATERIALS AND METHODS: Forty primary necrotic molars in healthy children, aged between 4 and 6 years underwent clinical and radiological assessment. A chemomechanical removal of pulpal necrotic debris was performed with 1% sodium hypochlorite irrigation. The canals were dried and Pulpotec was inserted in the pulp chamber, and the teeth were then restored. Clinical evaluation, vertical and horizontal measurements of the bone radiolucency were performed for up to one year after the Pulpotec procedure. STATISTICAL ANALYSIS: Wilcoxon signed-rank test was applied for comparison of groups. RESULTS: In this study 67.7% of patients showed healing of bone loss, and a significant difference in height and width of the lesion was observed (respectively 80.6%, 71%; p<0.05; p<0.025). CONCLUSION: This technique can be used as an alternative to conventional endodontic treatment for primary necrotic teeth. This procedure may allow paedodontists the ability to postpone extraction of necrotic teeth in particular situations or until eruption of the first permanent molar. Necrotic primary molars presenting furcation bone lesion due to infection may be treated with this modified Pulpotec procedure. With certain caveats, this procedure will preserve the molar on the dental arch for a certain period of time. In our study this technique yielded significant clinical improvements, but the radiological improvement is considered moderate. Future investigations are warranted in order to determine the possible effects of Pulpotec on the succedaneous teeth as well as their path of eruption.

Clinical Evaluation of Restorative Materials in Primary Teeth Class II Lesions.

OBJECTIVE: The aim of this study was to evaluate clinical success of primary teeth class II lesions restored with different restorative materials [Hybrid Composite Resin (HCR), Resin Modified Glass Ionomer Cement (RMGIC), compomer, and Giomer Composite Resin (GCR)] followed up for 24 months. STUDY DESIGN: This study was carried out on 146 primary molars of 41 children in the age range of 5-7 years. The class II lesions in primary molars of a patient were restored using different restorative materials. Restorations were evaluated according to FDI-criteria and their survival rates were determined. Data were analysed with Pearson chi-square, Kaplan-Meier and Wilcoxon (Breslow) tests (α = 0.05). RESULTS: The failure rates of restorative materials were as follows: compomer 33.3%, RMGIC 28.1%, HCR 22.5% and GCR 21.1%. CONCLUSIONS: While the functional failure was the most important factor in restorative material failure, RMGIC was the most successful material in terms of biological evaluation criterion and GCR had the longest survival rate.

Influence of the operatory field isolation technique on tooth-colored direct dental restorations.

PURPOSE: To evaluate, through a systematic review, the influence of the operatory field isolation technique on the longevity of dental restorations performed with tooth-colored materials. METHODS: An electronic search of the scientific databases (MEDLINE, SCIRUS, VHL and SIGLE) and reference lists of the selected articles was conducted to identify randomized controlled clinical trials with a follow-up period of at least 12 months. The selected articles evaluated the effects of the operatory field isolation techniques (rubber dam or cotton rolls/saliva ejector) on the longevity of direct restorations performed with tooth-colored materials (e.g. resin composites, compomers and glass-ionomer cements) in primary or permanent posterior teeth. The selected studies were analyzed and categorized using a checklist proposed by the National Institute for Health and Clinical Excellence of the United Kingdom. RESULTS: 484 studies were identified on the scientific databases. After applying the exclusion criteria and removal of duplicates, a total of nine studies were considered as potentially eligible. From these, five studies were included in the final analysis by two evaluators. In four studies analyzed, the use of rubber dam did not influence the longevity of restorations in comparison to cotton rolls/saliva ejector. Only two studies were considered as low risk of bias.

Finite element analysis of different restorative materials in primary teeth restorations.

AIM: The purpose of this finite element analysis (FEA) study is to evaluate and compare the stress distributions at the primary molars and restorative materials according to the material used. MATERIALS AND METHODS: A total of 12 3D models of Class II cavities in primary molars plus one control model were analysed. Study design: Three-dimensional FEA was used to compare stress distribution on enamel, dentin and restoration surfaces of cavities. STATISTICS: Stresses occurring under occlusal forces were compared with the von Mises criterion. RESULTS: The highest von Mises stress values at the enamel and restoration of restored tooth 84 were computed. On the basis of these results, all materials were ranked on enamel stress as: flowable composite resin (FCR)> compomer > resin modified glass ionomer cement (RMGIC) > giomer composite resin (GCR) > hybrid composite resin (HCR) > amalgam. Moreover, ranking of materials on restoration stress was FCR < compomer < RMGIC < GCR < amalgam < HCR. CONCLUSION: A restorative material with appropriate elasticity module, able to balance stress concentrations, should be used to increase the survival rate of both the hard tissue of the tooth and the restoration material.

In vitro evaluation of topical fluoride pH and their effect on surface hardness of composite resin-based restorative materials.

AIM: The aim of the study was to correlate the pH and fluoride ion uptake with surface hardness of composite resin based restorative materials after topical fluoride application. METHODOLOGY: Forty disks of each of test materials Composite (Filtek Z350XT, 3M ESPE, St Paul, MN, USA), Resin modified glass ionomer (Vitremer) and Compomer (Dyract AP) were made and ten disks of each material were placed in different test solutions - 1.23% APF gel, Sodium fluoride mouth rinse, 0.9% neutral fluoride and distilled water (Control group). After 36 hours of immersion, specimens were subjected to microhardness testing machine for evaluation of surface hardness. RESULTS: The greater hardness deterioration for all materials resulted with 1.23% APF gel when compared to the control group. Composite (Filtek Z350XT, 3M ESPE, St Paul, MN, USA) showed 17.13 VHN (control group 59.11 VHN). Vitremer showed 9.71 VHN (control group 37.71 VHN). Compomer showed 19.22 VHN (control group 36.78 VHN). CONCLUSION: 1.23% ApF gel significantly decreased hardness of composite, Vitremer and Compomer. Hardness deterioration associated with sodium fluoride mouth rinse and 0.9% neutral fluoride was less compared to 1.23% ApF gel.

Assessing changes in oral health-related quality of life following dental rehabilitation under general anesthesia.

OBJECTIVE: To determine whether dental treatment under general anesthesia (GA) improved oral health-related quality of life (OHRQoL) in pre-school children, to evaluate the sensitivity and responsiveness of the Turkish version of the Early Childhood Oral Health Impact Scale (ECOHIS) and to examine parental satisfaction with the care received. STUDY DESIGN: The parents/caregivers of 120 pre-school children receiving dental treatment under GA, were asked to complete the ECOHIS before and after treatment. Participants were also asked a global transition judgement concerning change in their child's condition after treatment. Global transition judgement and distribution changes in ECOHIS scores were used to assess the sensitivity and responsiveness. RESULTS: 98 children completed the follow-up survey. Between pre- and post-treatment ECOHIS scores, significant reduction was observed (p < 0.001). The effect sizes were moderate and large (0.36 to 1.63). Global transition rating groups were compatible with statistical differences between pre- and posttreatment scores, supporting the responsiveness of the ECOHIS. 91% of parents regarded the experience to be positive. CONCLUSIONS: Children's OHRQoL showed significant improvement after treatment. The majority ofparents reported a high degree of satisfaction. Also, Turkish version of the ECOHIS was sensitive to dental treatment under GA for pre-school children and responsive to treatment-associated changes.