Bulk-fill Composite Restorations Research Articles

Clinical Performance of Posterior Restorations Using a Universal Adhesive over Moist and Dry Dentin: A 36-month Double-Blind Split-mouth Randomized Clinical Trial

ObjectivesTo evaluate the influence of dentin moisture on the clinical behavior of a universal adhesive on posterior teeth after 36 months of follow-up. MethodsForty-five patients participated in this study. Following a split-mouth design, three operators placed 90 Class I/Class II restorations over moist dentin (MD) or dry (DD) (n=45) with resin composite (Filtek Bulk Fill) and a universal adhesive used in the etch-and-rinse mode (Single Bond Universal). Each restoration was evaluated according to the FDI and USPHS criteria (postoperative sensitivity, fracture and retention, marginal staining, marginal adaptation, and recurrence of caries) at baseline and after 6-, 12-, and 36 months. For statistical analysis, Kruskal Wallis analysis of variance rank (α = 0.05) and Kaplan-Meier survival analysis were used. ResultsNo significant difference between groups was observed in each FDI criterion after 36 months of clinical evaluation (p > 0.05). The retention rates (confidence interval 95%) were 97.37% (86.5 - 99.5) for both MD and DD without significant difference between them (p > 0.05). Eight restorations (MD = 4; DD = 4) showed minimal marginal staining defects (p > 0.05). Two restorations were lost (MD = 1; DD = 1). Fifteen restorations (MD = 8; DD = 7) presented minor marginal discrepancies according to the FDI criteria (p > 0.05). ConclusionThe clinical performance of the universal adhesive when applied in etch-and-rinse mode was not influenced by dentin moisture in posterior bulk-fill composite restorations. Clinical SignificanceThe level of dentin moisture appears not to influence the clinical efficacy of a universal adhesive when applied using the etch-and-rinse technique in posterior composite resin restorations.

Influence of surface sealants on the quality of posterior restorations with bulk-fill composites: A 4-year randomized clinical trial

ObjectivesThe aim of this study was to evaluate the clinical performance of surface sealants associated with a bulk-fill composite in posterior restorations after 4 years. MethodsA total of 174 posterior restorations were performed on 57 participants using a self-etch adhesive system and a bulk-fill composite. The groups were then divided into the following categories: 1) without surface sealant (NoS), 2) with surface sealant Biscover (Bisco, SBi), and 3) with surface sealant Permaseal (Ultradent, SPe). Restorations were evaluated using FDI criteria at baseline and after 1 and 4 years. Statistical analysis was conducted using Kaplan-Meier survival analysis and the Chi-square test (α = 0.05). ResultsAfter 4 years, only one restoration was lost (1 in the NoS group). The fracture/retention rate (with 95% confidence interval) was 98% for NoS and 100% for both SBi and SPe (p = 0.76). The majority of secondary outcomes showed minor defects, with no significant differences among the groups (p > 0.05). However, significant differences were observed among the groups in terms of marginal staining and marginal adaptation (p = 0.03). In both items, twelve restorations (nine in NoS, one in SBi, and two in SPe) showed minor marginal discrepancies favoring the sealant groups (SBi and SPe). SignificanceRegardless of the use of surface sealants, the bulk-fill composite restorations showed excellent clinical performance after 4 years. However, the groups that received sealants showed better marginal adaptation and less marginal discoloration compared to those that did not receive sealants.

A laboratory pilot study on voids in flowable bulk-fill composite restorations in bovine Class-II and endodontic access cavities after sonic vibration

This pilot study investigated whether sonic-powered application of a bulk-fill resin-based composite (RBC) in Class-II or endodontic access cavities reduces void formation. The crowns and roots of 60 bovine teeth with Class-II cavities (C) and endodontic access cavities (E) respectively, were assigned to ten groups (C1–C5, E1–E5). Cavities were filled with RBC (SDR flow + , one increment) using different application techniques: no adaptation (C1 + E1), spreading of RBC on the cavity surfaces with a dental explorer tip (C2 + E2), low (C3 + E3) or high frequency (C4 + E4) direct activation by inserting a sonic-powered tip into RBC and high frequency indirect activation with an ultrasonic insertion tip (C5 + E5). The restorations were light-cured and investigated for voids using microtomography. The number of voids and percentage of voids related to the volume were statistically analysed (α < 0.05). While most voids in Class-II restorations were observed in C4 (p ≤ 0.0031), no significant differences were found between the other groups (p > 0.05). The percentage of voids showed no differences in E1-E5 (p > 0.05). C4 showed a significantly higher percentage of voids compared to C2 (p < 0.001). There is no benefit in applying sonic vibration when filling Class-II or endodontic access cavities.

A Randomized Controlled Clinical Trial Evaluating the Performance of Bis-GMA Free Resin Composite Posterior Restorations

Objective: This study aims to assess the clinical performance of Bis-GMA free resin composites (RCs) in comparison with Bis-GMA based resin composites as posterior restorations during 1,3,6,9, and 12 months, using a split-mouth, double-blinded randomized design. Methods and Materials: The study included 20 participants who received a pair of class I or II bulk-fill composite restorations. One side of the mouth was filled with Bis-GMA free RC (Admira Fusion x-tra), while the other side received Bis-GMA based RC (X-tra fil). Restoration placement was done by a single operator following the manufacturer's guidelines and was finished and polished immediately following placement. Modified United States Public Health Services (USPHS) criteria have been adopted for restoration assessment at baseline (1 week), 1, 3, 6, 9, and 12 months. The statistical analysis was accomplished utilizing Wilcoxon tests, with a 0.05 significance level. Results: After 12 months, all patients attended the recall visits with a 100% recall rate. The Wilcoxon signed rank tests revealed insignificant differences between both groups (p?0.05) for all USPHS parameters. The two studied materials showed a decline from 100% clinically excellent scores, with a few recordings of clinically good scores at 12 months. However, most restorations maintained clinical Alpha and Bravo score throughout the 12-month period. Conclusions: The Bis-GMA-free RCs' clinical performance was comparable to that of Bis-GMA-based RCs in posterior permanent teeth restorations after 12 months. These findings suggest that Bis-GMA-free RCs can be considered a viable alternative to Bis-GMA-based RCs in clinical practice.

Marginal Integrity of Simplified Adhesive Strategies in Primary Teeth

The aim of this research was to investigate the effect of simplified adhesive strategies (self-etch vs selective enamel etch and 10- vs 20-second adhesive application time) on the marginal integrity in primary molars. Forty deep class-II cavities were prepared in 40 extracted primary molars. The molars were divided into 4 groups based on the applied universal adhesive strategy as follows: groups 1 and 2: selective enamel etch with 20- or 10-second application time and groups 3 and 4: self-etch with 20- or 10-second application time. All cavities were restored with a sculptable bulk-fill composite restoration. The restorations underwent a thermomechanical loading (TML, 5-50 °C, 2-minute dwelling time, ×1000; 400,000 loading cycles, 1.7 Hz, 49 N). Marginal analysis before and after TML was conducted with scanning electron microscopy and the marginal integrity of each restoration was calculated as a percentage of continuous margins. A beta regression model was adopted to statistically analyse the data with a consequent pairwise comparison. The mean marginal integrity (% ± SD) of the restorations for each tested adhesive strategy after TML was as follows: selective enamel etch/20 seconds=85.4 ± 3.9, self-etch/20 seconds=85.3 ± 5.2, self-etch/10 seconds=80.1 ± 8.2, and selective enamel etch/10 seconds=80.0 ± 8.5. The difference between both adhesive strategies was not statistically significant at the same application time. The difference between both application times within the same adhesive strategy was statistically significant (P ≤ .01). Universal adhesives applied either in selective enamel etch or in self-etch mode result in comparable marginal integrities when restoring class-II cavities in primary molars. Shortened adhesive application time (10 seconds) could lead to a reduction in the marginal integrity in comparison to the recommended application time of 20 seconds.

Microleakage and Marginal Integrity of Ormocer/Methacrylate-Based Bulk-Fill Resin Restorations in MOD Cavities: SEM and Stereomicroscopic Evaluation.

This in vitro study aimed to compare the microleakage and marginal integrity of methacrylate/ormocer-based bulk-fill composite (BFC) restorations used in cervical marginal relocation with two different layering thicknesses in mesio-occlusal-distal (MOD) cavities exposed to thermo-mechanical loading. Standard MOD cavities were prepared in 60 mandibular molars and assigned into three groups: x-tra fil/AF + x-tra base/XB, Tetric N-Ceram Bulk Fill/TNB + Tetric N-Flow Bulk Fill/TFB, and Admira Fusion x-tra/AFX + Admira Fusion x-base/AFB. Each group was further divided into two subgroups (2 mm and 4 mm) based on the thickness of flowable BFCs (n = 10). The specimens were subjected to thermo-mechanical loading (240,000 cycles) and immersed in 0.2% methylene blue. Following mesiodistal sectioning, the specimens were examined under stereomicroscope (×25) and scored (0-3) for microleakage. Marginal integrity was examined using a scanning electron microscope (SEM). Descriptive statistical methods and the chi-square test were used to evaluate the data (p < 0.05). While there was no statistically significant difference in gingival cement microleakage in the XB and AFB specimens with a 4 mm thickness, microleakage was significantly increased in the TFB specimen (p = 0.604, 0.481, 0.018 respectively). A significantly higher amount of score 0 coronal microleakage was detected in the AFX2 mm + AFB4 mm compared to the TNB2 mm + TFB4 mm (p = 0.039). The SEM examination demonstrated better marginal integrity in groups with 2 mm thick flowable BFCs. Ormocer and methacrylate-based materials can be used in marginal relocation with thin layers.

Clinical comparison of different glass ionomer-based restoratives and a bulk-fill resin composite in Class I cavities: A 48-month randomized split-mouth controlled trial

ObjectiveThe aim of this study is to compare the retention rates (primary outcome) of high-viscosity glass ionomer (GI), glass carbomer (GC), zirconia-reinforced GI (ZIR), and bulk-fill (BF) composite resin restorations. Secondary outcomes included anatomical form, marginal adaptation, marginal discoloration, color match, surface texture, post-operative sensitivity and secondary caries. MethodsTwo calibrated operators placed 128 restorations in 30 patients with a mean age of 21 years. The restorations were evaluated by one examiner at baseline and at 6, 12, 18, 24, and 48 months using the modified US Public Health Service criteria. The data were statistically analyzed using Friedman test. Differences between restorations were analyzed using Kruskal–Wallis test. ResultsAfter 48 months, 23 patients and 97 restorations (23 GI, 25 GC, 24 ZIR, and 25 BF) were evaluated. Patient recall rate was 77%. No significant difference was observed between the retention rates of the restorations (p > 0.05). GC showed significantly lower results than the other three fillings in terms of anatomical form (p < 0.05). There was no significant difference in the anatomical form and retention between GI, ZIR, and BF (p > 0.05). No significant change was observed in the postoperative sensitivity or secondary caries for any of the restorations (p > 0.05). ConclusionsGC restorations showed statistically lower anatomical form values, indicating lower wear resistance than the other materials. However, no significant difference was observed in the retention rates (as primary outcome) as well as the other secondary outcomes of the four different restorative materials after 48 months. Clinical SignificanceGI-based restorative materials and BF composite resin restorations in Class I cavities yielded satisfactory clinical performance after 48 months.

Effect of radiant emittance of an LED curing light on the cuspal deflection of a simulated tooth cavity in bulk-fill composite restoration: A novel simulation method.

In this study, a novel method for simulating human teeth was developed, with which the effect of radiant emittance of an LED curing light on the cuspal deflection was investigated. A mesio-occluso-distal (MOD) cavity was replicated using a heat-pressed ceramic and lost wax technique, and the cuspal compliance and cuspal deflection of the replicated ceramic teeth and extracted human teeth were evaluated. The replicated ceramic teeth were restored using a nano bulk-fill composite and photopolymerized using three different protocols. Data were analyzed with t-test and one-way ANOVA (α=0.05). The cuspal compliance and cuspal deflection of the replicated ceramic teeth and extracted human teeth were similar. Cuspal deflections did not differ significantly among the tested photopolymerization protocols. Thus, the replicated ceramic teeth were an effective simulation of human teeth. During bulk-fill composite restoration of the MOD cavity, cuspal deflection was not affected by changing the radiant emittance of the LED light.

Marginal integrity of classical and bulk-fill composite restorations in permanent and primary molars

Bulk-fill composites enable timesaving and less technical-sensitive application of restorations. This study investigated and compared the marginal integrity of classical and bulk-fill composite restorations in primary and permanent molars before and after thermo-mechanical loading (TML). Two Class II cavities were prepared in each of 20 primary and 20 permanent molars. The molars were randomised in four groups for each molar type. Groups 1 and 5 were restored with a high-viscous bulk-fill composite (Tetric PowerFill), groups 2 and 6 were restored with a flowable bulk-fill composite (Tetric PowerFlow), groups 3 and 7 were restored with a high-viscous classical composite (Tetric Prime), and groups 4 and 8 were restored with a flowable classical composite (Tetric EvoFlow). In permanent molars, the flowable composites were covered with a 2-mm layer of high-viscous composite (groups 6 and 8). The restorations were subjected to TML in a custom-made chewing machine (5–50 °C, 2 min dwelling time, × 1000; 400 ,000 loading cycles, 1.7 Hz, 49 N), and quantitative marginal analysis was conducted using scanning electron microscopy. Marginal integrity of each restoration was calculated as a percentage of continuous margins before and after TML. The tested high-viscous bulk-fill restoration showed similarly high marginal integrity in primary and permanent molars as the classical restoration. The tested flowable bulk-fill restoration showed the lowest marginal integrity compared to all other restorations after TML. In contrast to flowable bulk-fill restorations, high-viscous bulk-fill restorations show similar marginal integrity as classical hybrid composite restorations after TML, in both primary and permanent molars.

Influence of Practitioner-Related Placement Variables on the Compressive Properties of Bulk-Fill Composite Resins-An In Vitro Clinical Simulation Study.

Aims: To determine if restoration location and/or execution behavior force parameters have an influence on the mechanical properties of bulk-fill composite dental restorations. Methods: Pressure transducers were placed within each quadrant of dental mannequin jaws. Cylindrical molds were placed above the transducers and filled with two bulk-fill composite materials, Filtek and Tetric, by four experienced dentists. Each dentist prepared five specimens per quadrant and material. The total placement time, mean force, number of peak forces (above 25 N), and mean peak(s) force during placement were measured. Then, the stiffness and maximal compressive strength of the specimens were determined while loading the specimens up to failure using a universal loading machine. Results: Placement time was affected by jaw (p < 0.004) and side (p < 0.029), with the shortest time demonstrated for the left side of the mandible. Force exerted during restoration placement was not normally distributed without differences in location (jaw) or material. A higher application force was found on the right side (p < 0.01). The number of peak forces was affected by side (p < 0.03), with less peaks on the left side. No significant differences were found in compressive strength when correlated to restoration location, participant, or material (p = 0.431). The stiffness values of Filtek (3729 ± 228 N/mm) were found to be 15% higher than Tetric (3248 ± 227 N/mm) (p < 0.005). No correlations were found between the compressive strength or stiffness and the amount of force applied during placement. Conclusions: The individual restoration material placement parameters did influence practitioner performance; however, these differences did not affect the mechanical properties of the final restoration.

Influence of Matrix Type on Marginal Gap Formation of Deep Class II Bulk-Fill Composite Restorations.

Background: To test the hypothesis that transparent matrices result in more continuous margins of bulk-fill composite (BFC) restorations than metal matrices. Methods: Forty standardized MOD cavities in human molars with cervical margins in enamel and dentin were created and randomly assigned to four restorative treatment protocols: conventional nanohybrid composite (NANO) restoration (Tetric EvoCeram, Ivoclar Vivadent, Schaan, Liechtenstein) with a metal matrix (NANO-METAL) versus transparent matrix (NANO-TRANS), and bulk-fill composite restoration (Tetric EvoCeram Bulk Fill, Ivoclar Vivadent, Schaan, Liechtenstein) with a metal matrix (BFC-METAL) versus transparent matrix (BFC-TRANS). After artificial aging (2500 thermal cycles), marginal quality was evaluated by scanning electron microscopy using the replica technique. Statistical analyses were performed using the Mann–Whitney U-test and Wilcoxon test. The level of significance was p < 0.05. Results: Metal matrices yielded significantly (p = 0.0011) more continuous margins (46.211%) than transparent matrices (27.073%). Differences in continuous margins between NANO (34.482%) and BFC (38.802%) were not significant (p = 0.56). Matrix type did not influence marginal gap formation in BFC (p = 0.27) but did in NANO restorations (p = 0.001). Conclusion: Metal matrices positively influence the marginal quality of class II composite restorations, especially in deep cavity areas. The bulk-fill composite seems to be less sensitive to the influence of factors such as light polymerization and matrix type.

Bond strength of bulk-fill resin composites

Aim: Evaluating the resin-dentin bond strength of Class II conventional and bulk-fill composite restorations, using different cavity sizes before and after aging. Methods: Seventy-five human molars were distributed into groups according to the buccolingual width of the cavities, conservative (n=25) and extended (n=50). They were divided according to the restorative material: conventional (Z100/control group) or bulk-fill resin composites (Filtek Bulk Fill/FBF; Tetric N Ceram Bulk Fill/TNCBF; Filtek Bulk Fill Flow/FBFF; Surefill SDR flow/SDR). The restored teeth were sectioned on sticks (n=50 per restorative materials + width cavities group), half were stored in Water/Ethanol 75% for 30 days and the other half were submitted to the immediate microtensile bond strength (μTBS) test. Data were analyzed applying the Three-Way Analysis of Variance (ANOVA), Bonferroni test, test t, and Weibull analyses (p&lt;0.05). Results: SDR and FBF presented lower μTBS values for extended preparation when compared to the conservative preparation, before aging. After aging, only for the FBFF, a decrease in the μTBS values was observed. Comparing the μTBS values, before and after aging, the SDR demonstrated lower μTBS values after aging when the conservative cavity was used. A decrease in the μTBS values was observed for the Z100, the FBF and, the FBFF, after aging, when the extended cavity was used. Conclusion: The effect of cavity preparation and aging on the resin-dentin of Class II is material dependent. Most of the bulk-fill resin composites evaluated presented a similar performance to the conventional resin composites for all the conditions of this study.

Effect of Dentin Moisture in Posterior Restorations Performed with Universal Adhesive: A Randomized Clinical Trial.

This double-blind, randomized clinical trial evaluated the influence of dentin moisture on postoperative sensitivity (POS), as well as, on clinical performance in posterior bulk-fill composite restorations, using a universal adhesive, until 12 months after clinical service. In accordance with a split-mouth design, 45 patients received posterior restorations, restored with a bulk-fill resin composite (Filtek Bulk Fill, 3M Oral Care) and a universal adhesive used in etch-and-rinse mode (SBU; Single Bond Universal Adhesive), which were applied on dry or moist dentin, with a cavity depth of at least 3 mm. Three operators placed 90 Class I/Class II restorations. Patients were evaluated for spontaneous and stimulated POS in the baseline, and after 48 hours, 7 days, and at 6 and 12 months. In addition, secondary parameters (marginal discoloration, marginal adaptation, fracture, and recurrent caries) were evaluated by World Dental Federation (FDI) criteria after 7 days and at 6 and 12 months. Statistical analyzes were performed using the Chi-square, Fisher exact, Friedman, Kruskall-Wallis, and Mann-Whitney tests (α=0.05). No significant spontaneous and stimulated POS was observed when SBU was applied in dry and moist dentin (p>0.05). A significant and higher risk of spontaneous POS (20.0%; 95%CI 10.9-33.82 for dry dentin and 22.22%; 95%CI 12.54-36.27 for moist dentin) occurred up to 48 hours after restoration placement for the dry and moist dentin groups (p<0.02). However, the POS intensity was mild up to 48 hours with no significant difference between dry and moist dentin groups (p>0.79). When secondary parameters were evaluated, no significant differences between the groups were observed. Dentin moisture did not influence POS in posterior bulk-fill composite restorations when associated with a universal adhesive applied in etch-and-rinse mode.

One-year clinical evaluation of bulk-fill composite resin restorations plasticized by preheating and ultrasonics: A randomized clinical trial.

Introduction:Bulk-fill composite restorations displayed substantial annual failure related to imperfect marginal adaptation. Although preheated composites improved, marginal adaptation demonstrated early loss of plasticity. A new technique of ultrasonics plasticization was used for fabricating restorations.Aim:The aim of this study was to assess the clinical behavior of bulk-fill composite resin restorations plasticized by preheating and ultrasonics.Methodology:Randomized split-mouth double-blinded clinical trial was designed. Bulk-fill composite resin (Tetric N-Ceram Bulk Fill Ivoclar Vivadent products, Delhi) was used to fill 56 cavities. In 28 restorations, composite resin was plasticized by preheating in composite warmer (Delta Co., India) and remaining were plasticized with modified ultrasonic–retreatment tip-RT No 2 (Cricdental, India). Clinical follow-up assessments were done at 6 and 12 months using Ryge's criteria. Mann–Whitney U-test was used for statistical analysis with P < 0.05 and effect size of 0.61.Results:Hundred percent clinical success with ultrasonic plasticized group and 95.2% success with preheated composite resin group were observed without statistical significance.Conclusion:The ultrasonics plasticization of composite resin demonstrated comparable results with that of preheated composite resin after 6- and 12-month recall. Use of vibration energy utilizing the thixotropic effect might have resulted in better clinical performance.

Evaluation of the Quality of Margins in Class ІІ Bulk Fill Composite Restorations when Restored in Bulk and in the Incremental Filling Technique Using the Total Etch and Self Etch Technique

Objective: To evaluate the marginal quality of class II composite restorations using a bulk fill composite when restored in bulk compared to an incremental filling technique following two different modes of bonding, total etch and self-etch technique. Methods: Forty-eight standardized class II box-shaped cavities were prepared on both the proximal surfaces of twenty-four mandibular molar teeth. Cavities were prepared with no-245 carbide bur on proximal surfaces. The teeth were divided into two groups, Group 1 which followed the self-etch strategy (n=12) and Group 2 which followed a total etch strategy (n=12). Each group was further divided into two subgroups based on the restorative technique followed, Sub group A – cavities on the mesial side which were bulk filled and Sub group B – cavities on the distal side which were incrementally filled. Specimens were placed in 2% methylene blue dye for 24 hrs and were then sectioned. Specimens were evaluated under stereomicroscope for microleakage. Data obtained was statistically analyzed using Kruskal Wallis test and Dunn’s multiple comparison test. Results: The results showed that between the two groups, the total etch technique showed the highest microleakage. Greater microleakage was observed in bulk fill technique when compared with incremental technique in group II. Conclusion: The degree of microleakage in a class II composite restoration is influenced not only by the adhesion strategy followed for the bonding agent, but also by the technique followed during composite restoration

Micro-computed tomography for assessing the internal and external voids of bulk-fill composite restorations: A technical report.

PurposeThis technical report aims to describe and detail the use of micro-computed tomography for a reliable evaluation of the bulk-fill composite/tooth interface.Materials and MethodsBulk-fill composite restorations in tooth cavities were scanned using micro-computed tomography to obtain qualitatively and quantitatively valuable information. Two-dimensional information was processed using specific algorithms, and ultimately a 3-dimensional (3D) specimen reconstruction was generated. The 3D rendering allowed the visualization of voids inside bulk-fill composite materials and provided quantitative measurements. The 3D analysis software VG Studio MAX was used to perform image analysis and assess gap formation within the tooth-restoration interface. In particular, to evaluate internal adaptation, the Defect Analysis add-on module of VG Studio Max was used.ResultsThe data, obtained with the processing software, highlighted the presence and the shape of gaps in different colours, representing the volume of porosity within a chromatic scale in which each colour quantitatively represents a well-defined volume.ConclusionMicro-computed tomography makes it possible to obtain several quantitative parameters, providing fundamental information on defect shape and complexity. However, this technique has the limit of not discriminating materials without radiopacity and with low or no filler content, such as dental adhesives, and hence, they are difficult to visualise through software reconstruction.

Effect of Stress Generated by Occlusal Cyclic Force on Class I Bulk-Fill Composite Restoration Microleakage.

Objective This study aimed to evaluate the effects of different types and restorative techniques of Class I composite restorations with a single loading force on stress distribution and cyclic loading force on microleakage formation. Materials and Methods Class I cavities were prepared in premolars with 4 mm depth and divided into six groups of different restorations with: (1) Filtek Z250; (2) a 3-mm-thick layer of Filtek Bulk Fill Flowable Restoration and covered with Z250; (3) a 1.5-mm-thick layer of flowable composite and covered with Z250; (4) lining all cavity with flowable composite and restored with Z250; (5) Filtek Bulk Fill Posterior Restoration; and (6) lining all cavity with flowable composite and restored with bulk-fill composite. The specimens with and without cyclic occlusal loading were subjected to microleakage observation. In addition, six different models of Class I restorations corresponding to the microleakage study were generated. Finite element analysis (FEA) was used to identify the stress distribution under a single loading force. Statistical Analysis Data were statistically analyzed by two-way analysis of variance and multiple comparison. The significance level set at 0.05. Results Cavity lining or restoration with flowable composite underneath conventional composite reduced stress on composite resin based on FEA (groups 2 and 3). The cyclic stress on composite increased microleakage. Restoration with flowable composite underneath conventional composite reduced the microleakage in Class I restoration (groups 2, 3, and 4). Conclusion The most effective cavity lining with a flowable composite underneath conventional composite restoration was stress reduction under loading force resulting in microleakage reduction.

Reliability of Class II Bulk-fill Composite Restorations With and Without Veneering: A Two-year Randomized Clinical Control Study.

Bulk-fill composites are increasingly used in stress-bearing areas in posterior teeth, with a diversity of reports concerning their effectiveness and clinical reliability. The objective of this randomized clinical control study was to investigate the effectiveness of bulk-fill versus veneered bulk-fill Class II composite restorations. A double-blind split-mouth technique was employed in 80 subjects recruited for restoring Class II caries in one molar bilaterally in the same arch following respective inclusion and exclusion criteria and after obtaining written consent. While one molar was randomly restored with bulk-fill composite using the sealed-envelope technique, Tetric N-Ceram Bulk Fill (TBF), the contralateral was restored with a bulk-fill composite veneered with an increment of a heavy-body microhybrid composite-Tetric-Ceram HB (TBF/V). Box-only cavities were prepared and received etch-and-rinse adhesive bonding and Tetric N-Bond treatment before composite insertion. Restorations were assessed at 24 hours, 2 weeks, 6 months, 12 months, and 24 months for esthetic, functional, and biological quality employing the FDI ranking criteria. Friedman repeated-measures analysis of variance, the McNemar test, and the Cohen's kappa statistical test were used for statistical analysis. Over a 24-month interval, none of the test restorations were ranked as clinically unsatisfactory. In terms of functional criteria, clinically excellent restorations were significantly more prevalent in TBF/V than in TBF (p<0.05). For long-term satisfactory performance of Class II bulk-fill composites, an occlusal veneering increment of conventional heavy body microhybrid composite appears to be favorable.

¿Pueden las restauraciones de resina bulk-fill ser una alternativa a las restauraciones de cemento de ionómero de vidrio modificado con resina en los molares primarios en niños preescolares? Un protocolo de ensayo clínico aleatorizado

Background: The aim of this study was to elaborate a randomized clinical trial protocol to evaluate the effectiveness of class I restorations in resin-modified glass ionomer cement (RMGIC) and bulk-fill resin in primary molars with untreated early childhood caries in toddlers. Material and Methods: A total of 59 toddlers up to 36 months old with at least two primary molar teeth with untreated dental caries of single surface on different sides of the mouth will be selected at the Pediatric Dentistry Clinics of the Faculty of Dentistry at Federal University of Minas Gerais (UFMG), Brazil. Teeth with untreated dental caries in the left and right sides of each patient’s mouth will be randomly distributed into 2 groups: Group 1 (Control): encapsulated RMGIC restoration with Riva light cure (SDI, Florida, USA) and Group 2 (Test): Filtek bulk-fill composite resin restoration (3M/ESPE, St. Paul, USA) with universal single bond adhesive system (3M/ESPE, St. Paul, USA). A single trained dentist will perform all restorative procedures. The restorations will be evaluated after 1, 6, 12, 18 and 24 months by two trained and calibrated examiners. Cost-efficacy analysis will be carried out. Kaplan-Meier survival analysis, Log-rank test, Cox regression, Poisson regression analysis, Mann-Whitney test or Kruskal-Wallis will be performed to analyze data. Conclusion: The protocol will make it possible to determine the most efficacy material for the restoration of cavities in cavities in primary molars of toddlers.

Effects of wall compliance and light-curing protocol on wall deflection of simulated cavities in bulk-fill composite restoration

Background/purposeCuspal deflections in composite restoration have been investigated with considering wall compliance of human tooth cavity and light-curing protocol. The purpose of this study was to investigate effects of mold wall compliance and radiant emittance of LED light on the wall deflection of simulated aluminum mold cavities restored with a bulk-fill composite.Materials and methodsSixty aluminum molds simulating a class II mesio-occluso-distal (MOD) cavity (6 W × 8 L × 4 D mm; W, width; L, length; D, Depth) were prepared and allocated to three groups with varying mold wall thicknesses of 1, 2, and 3 mm. The molds were bulk-filled with a bulk-fill composite and photo-cured. Four light-curing protocols were used: three duty ratios/exposure times: 100%/20 s, 50%/40 s, or an increasing mode (0 → 100%)/40 s with a pulse width modulated (PWM) LED curing light and one 20 s exposure time with a commercial LED light.ResultsMean mold wall deflection at 2000 s decreased with increasing mold wall thickness (1, 2, and 3 mm) (p < 0.05). Wall deflections with 1- and 2-mm-thick molds exhibited no statistically significant differences among light-curing protocols (p > 0.05). However, in the 3-mm-thick mold, wall deflections with low radiant emittance were significantly lower than those with high radiant emittance (p < 0.05).ConclusionIn composite restoration of class II MOD cavities, lowering the radiant emittance of LED light can reduce the mold wall deflection only in low compliance cavities.