Marginal Adaptation Of Composite Restorations Research Articles

Adaptability of VisCalor versus bulk-fill composites using scanning electron microscope: an in-vitro study

Purpose To evaluate the marginal integrity of two types of bulk-fill composite resins in Class I box-shaped cavities. Materials and methods Forty extracted human sound molars were selected. The teeth were fixed with sticky wax to the base of plastic cylinder and the cylinder was filled with self-curing acrylic resin so that only root was embedded. Simple Class I box-shaped cavities were prepared using a fissure carbide bur with water spray and finished with fine-grained flame burs. The overall dimensions and depth of the cavities were standardized as follows: 4 mm length mesiodistally and 3 mm width buccolingually and up to 4 mm depth. All prepared cavities were bonded using Futurabond M+ one-step self-etch adhesive system. The teeth were randomly divided into two groups (n = 20 teeth each): group I: specimens were restored with VisCalor composite bulk-fill composite resin, which is heated before insertion using a VisCalor dispenser dental device. Group II: specimens were directly restored with X-tra fill bulk-fill composite resin without preheating. After curing, finishing and polishing were performed. Each group was subdivided into two subgroups a and b (n = 10) according to whether subjecting 500 thermocycling fluctuations or not. Each specimen was sectioned buccolingually through the center of the composite resin restoration in two halves, and then cleaned under running tap water and subjected to thorough ultrasonic cleaning to get rid of both soft and hard surface deposits. All sectional samples were fixated in cylindrical carriers, and a thin layer of gold was applied to the surfaces. The marginal adaptation of composite restorations and ultramorphology of adhesive bonds were analyzed at ×50, ×1000 magnification, with a scanning electron microscope. ×50 magnification was utilized to measure the length of margins free gap in enamel and dentin by Autodesk Auto CAD program and expressed in mm/percent. All data of measurements of the length of nongaped margins in enamel and dentin are collected, tabulated, and statistically analyzed. Results Group Ia (VisCalor bulk-fill not thermocycled), recorded the highest mean value of marginal free-gap with 10.26 ± 0.27 mm (93.31%), while group IIb (X-tra-fill bulk-fill thermocycled) recorded the lowest mean value in 7.90 ± 0.26 mm (73.04%) and the difference was statistically highly significant (P = 0.000). In general, group I recorded higher mean values of marginal free gap and adaptation in mm/percent than group II, and the difference was statistically highly significant at P value of 0.000 (9.86 ± 0.55 and 8.23 ± 0.39 mm and 89.15 ± 5.38 and 74.89 ± 3.69%, respectively). Bulk-fill restorations without thermocycling exhibited a higher mean value of marginal free gap and adaptation in mm/percent than the thermocycled one with a significant difference recorded at P value of 0.005. Conclusion Using preheated VisCalor bulk-fill composites could decrease the marginal gap formation improving the continuity at the tooth–restorative material interface than conventional bulk-fill restorations. On the other hand, thermocycling.

Evaluation of Marginal Adaptation of Composite Restorations Reinforced with Novel Enamel Inserts (Biofillers) in Class V Cavities

To evaluate the marginal adaptation at the tooth-restoration interface at enamel and cementum margins using composite restoration reinforced with novel enamel inserts/biofillers. Standardized class V box-shaped cavities were prepared in 40 extracted maxillary first premolar teeth which were divided randomly into four experimental groups consisting of 10 samples each. Group I: Bulk placement. Groups II: Horizontal incremental technique. Group III: Restoration with precured composite balls (megafillers). Group IV: Restoration with biofillers. All the cavities were restored with visible light-activated direct restorative nanocomposite. The specimens were thermocycled for 24 hours. After thermocycling, the samples were immersed in a 1% methylene blue for 4 hours and subsequently evaluated for microleakage. Microleakage scores (0-4) were obtained from gingival margins of class V restorations and analyzed by statistical analysis. Evaluation of the data was performed by Kruskal-Wallis one-way analysis of variance (ANOVA), and Mann-Whitney U tests. Microleakage scores have indicated restorations with biofillers showed best results followed by megafillers, incremental horizontal build-up, and bulk filling. Biofillers provide a novel approach in improving microleakage and marginal adaptability of composite resin restorations. Incorporation of inserts, which are capable of adequate bonding to resin and tooth, may provide improved marginal adaptability and reduce microleakage around restorative margins.

Evaluation of Esthetics and Marginal Adaptation of Composite Restorations for Fractured Permanent Incisors

Evaluation of Esthetics and Marginal Adaptation of Composite Restorations for Fractured Permanent Incisors

Application of Calcium Silicate Materials After Acid Etching May Preserve Resin-Dentin Bonds.

The aim of the present study was to evaluate the effect of the application of calcium silicate materials (CSMs), after acid etching, on the longevity of the hybrid layer and marginal adaptation of composite restorations. Eighty human permanent molars received an intrapulpal pressure of 15 cm H2O. Sixty teeth received a mesial proximal slot preparation with the gingival margin extending 1 mm below the cemento-enamel junction. The samples were divided into two groups. Group 1 received restorations using two types of etch-and-rinse adhesives: ethanol based (Single Bond, 3M ESPE, St Paul, MN, USA) and acetone based (Prime & Bond NT, Dentsply, DeTrey GmbH, Germany). In group 2 samples, a commercially available CSM (ProRoot MTA) was allowed to set before grinding and placing into a distilled water solution. This solution was applied on the cavity floor after acid etching. The surface was washed after 30 seconds followed by application of adhesives and restorations as in group 1. The samples were stored in phosphate-buffered saline for six months, maintaining the intrapulpal pressure. An epoxy replica was made, and the marginal adaptation was evaluated using scanning electron microscopy. The percentage of continuous margin (CM) was recorded for each group. Another 20 samples were used for hybrid layer evaluation. The crowns were ground to expose dentin. Intrapulpal pressure was applied. The samples were divided into two groups and restored similar to samples restored for marginal adaptation evaluation. The samples were longitudinally cut in 1-mm slices. The slices were stored under 15 cm of phosphate-buffered saline to simulate the pulpal pressure. After six months, the adhesive interface was evaluated using a scanning electron microscope. Statistical analysis was done with two-way analysis of variance with Holm-Sidak's correction for multiple comparisons. Application of CSMs improved the marginal adaptation values in both adhesive groups. In group 1, there were areas of incomplete penetration of resins along with evidence of partial degradation of resin tags. Samples receiving CSM application after acid etching demonstrated long and regular resin tags with very few signs of degradation. Application of CSMs after acid etching can be a potential avenue in preserving the resin-dentin bonds.

Effect of Cavity Contamination by Blood and Hemostatic Agents on Marginal Adaptation of Composite Restorations.

To determine the effects of contamination of tooth cavities by hemostatic agents applied after blood contamination on marginal adaptation of composite restorations bonded with etch-and-rinse and self-etch adhesives. Cervical cavities (n = 10 per group) were contaminated with blood and subsequently treated with aluminum chloride (Racestyptine) or ferric sulfate (Astringedent, ViscoStat) hemostatic agents. After water rinsing, composite restorations were placed using either an etch-and-rinse (OptiBond FL) or self-etch (OptiBond All-in-One) adhesive. EDS-based elemental surface analysis was performed, and marginal integrity was evaluated using SEM both before and after thermomechanical loading. The percentage of continuous margins in enamel (%CEM) and dentin (%CDM) was statistically analyzed (p < 0.05). No statistically significant differences in %CEM and %CDM were observed between hemostatic-contaminated groups and uncontaminated controls after thermomechanical loading, irrespective of the adhesive used. Specimens contaminated with aluminum-chloride-based Racestyptine showed a significantly higher final %CEM when the etch-and-rinse adhesive was applied (OptiBond FL) than with the self-etch adhesive (OptiBond All-in-One). Cavity contamination with hemostatic agents, applied after blood contamination and removed with water spray, does not compromise marginal adaptation in enamel and dentin. In the case of contamination by an aluminum-chloride hemostatic agent, the tested etch-and-rinse approach resulted in a higher percentage of continuous enamel margins of composite restorations than did the self-etch approach.

Light polymerization during cavity filling: influence of total energy density on shrinkage and marginal adaptation

The aim of the study was to evaluate the marginal adaptation and shrinkage stress development of a micro hybrid restorative composite as a function of energy density. Linear displacement and shrinkage forces were measured with custom-made devices for energies of 4,000, 8,000, 16,000 and 32,000 mJ/cm(2) at a constant power density of 800 mW/cm(2). Marginal adaptation of composite restorations cured with the same energy density was evaluated before and after mechanical loading with 300,000 cycles at 70 N. The group "4,000 mJ/cm(2)" showed the lowest shrinkage force [2.9(0.2) kg] and linear displacement [23.5(0.7) μm] but led to the worst marginal adaptation after loading [46.4(23.5) %CM] probably due to under-curing. When the maximum energy of 32,000 mJ/cm(2) was applied, a slight increase in shrinkage forces [3.6(0.2) kg and 29.2(0.8) μm], and a slight decrease in marginal adaptation after loading [75.4(11.5) %CM] were observed, but these changes were not significantly different in comparison to groups cured with energies of 8,000 and 16,000 mJ/cm(2). For the resin composite tested in this study, no differences in marginal adaptation could be detected above the energy threshold of 8,000 mJ/cm(2).

Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling

Objective:This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations.Material and Methods:Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5ºC±2ºC followed by 55ºC±2ºC - T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz - T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (a=0.05).Results:The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition.Conclusions:The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations.

Does bonding to Dentin reduce Gap formation in Composite Restorations?

ABSTRACT This study evaluated the effect of adhesive application only to enamel on the gap formation of composite resin restorations performed with different adhesive systems and submitted to mechanical cycling. Standardized cylinder-shaped cavities were prepared on the buccal surface of 60 bovine incisors. Two etchand-rinse [Adper Scotchbond Multi-purpose (3M ESPE, St. Paul, MN, USA) and Adper Single Bond 2 (3M ESPE)] and one selfetching [Clearfil SE Bond (Kuraray, Osaka, Japan)] adhesive systems were evaluated. The adhesives were applied only to enamel or to both dentin and enamel. After adhesive light activation, the cavities were restored with composite resin. The restorations were finished and polished; the marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500× magnification) in low-vacuum mode. After the first evaluation, the samples were submitted to mechanical cycling (300,000 cycles of 80 kN and 1.5 Hz) and a new evaluation was performed. There was observed any gap for all experimental conditions before and after mechanical cycling. Bonding to dentin does not alter the marginal adaptation of composite restorations. How to cite this article Popoff DAV, Menezes MS, Gomes AS, Faria-e-Silva AL, Soares PV, Santos-Filho PC, Martins LRM. Does bonding to Dentin reduce Gap formation in Composite Restorations? Int J Experiment Dent Sci 2012;1(2):67-70.

Non-destructive 3D imaging of composite restorations using optical coherence tomography: Marginal adaptation of self-etch adhesives

Objectives To investigate the potential use of swept-source optical coherence tomography (SS-OCT) as a new tool to evaluate marginal adaptation of composite restorations in class I cavities. Methods Round-shaped class I cavities (3 mm diameter × 1.5 mm depth) were prepared on buccal enamel of bovine teeth with cavity floor located in dentine. The cavities were restored with a flowable resin composite (Clearfil Majesty LV) using two-step self-etch adhesive (SE Bond), all-in-one self-etch adhesive (G-Bond) or no adhesive (Control). The specimens were subjected to water storage (37 °C, 24 h) or thermal stress challenge (5000 cycles, 5 °C and 55 °C). 3D scans (4 mm × 4 mm × 2.6 mm obtained in 4 s) of the restoration were obtained using SS-OCT before and after immersion into a contrast agent. 2D images obtained from the 3D scans ( n = 30/group) were analysed to evaluate marginal adaptation. Area fraction of pixels with high brightness values at the interfacial zone was calculated using a digital image analysis software. The results were statistically compared with statistical significance defined as p ≤ 0.05. Results Wilcoxon signed ranks test showed that there was no statistically significant difference in the results of SS-OCT before and after infiltration of the contrast agent when a ranking transformation was applied on to the data ( p > 0.05). A significant positive linear correlation was found between the two SS-OCT images. Confocal laser scanning photomicrographs of samples cut after silver infiltration confirmed the presence of gap. Conclusions 3D imaging by SS-OCT can be considered as a non-invasive technique for fast detection of gaps at the restoration interface.

Effect of prepolymerized composite megafiller on the marginal adaptation of composite restorations in cavities with different C-factors: An SEM study

To evaluate the effect of prepolymerized custom-made composite megafiller and configuration factors (C-factor) on marginal adaptation of resin composite restorations. Forty extracted human mandibular molars were divided into four experimental groups consisting of 10 samples each. In groups I and III, class V (configuration factor 5) and in groups II and IV, class II box-shaped cavities (configuration factor 2) were prepared. Groups I and II were restored with a nanofilled composite (Filtek™ Z350 3M ESPE, St Paul, MN, USA) placed in horizontal increments. In groups III and IV, preformed composite megafiller was placed and cavities were restored with nanofilled composite Z-350. After curing, the samples were finished and prepared for examination under low vacuum scanning electron microscope. The data were analyzed with one-way analysis of variance. The significance between the individual groups was calculated by Post hoc test using the Holm-Sidak method ( P≤0.05). The marginal gap values in groups III and IV were significantly lower than in groups I and II, respectively ( P≤0.05). Minimum gap values were seen in group IV. Use of prepolymerized composite megafiller and a lower C-factor decreased the marginal gaps between the tooth and composite restorations.

Transdental Photo-activation Technique: Hardness and Marginal Adaptation of Composite Restorations Using Different Light Sources

This study investigated the influence of different light sources associated with a transdental photoactivation technique on the marginal adaptation and hardness of composite restorations. Cavities (3 mm wide x 3 mm long x 1.5 mm in deep) were prepared on flattened bovine dentin and filled with Z250 composite (3M ESPE). Nine groups (n=10) were defined according to the curing technique (direct; transdental--photo-activation through 1 mm of enamel and 2 mm of dentin; mixed--transdental + direct) and light source (QTH XL2500, 3M ESPE; PAC Apollo 95E, DMD; LED Ultrablue Is, DMC) combination. Marginal adaptation was evaluated using a dye staining method, and the percentage of stained margins was recorded. Knoop Hardness readings were made across the transversal section of the fillings. Data were submitted to two-way ANOVA and Tukey's test (p< or =0.05). For margin analysis, although none of the curing conditions provided perfect adaptation, the mixed technique showed lower gap formation. No significant differences were detected between the transdental and other techniques, and no significant differences were detected among the light sources. For hardness, the direct technique showed slightly greater hardness than the mixed technique. Also, the mixed technique yielded greater hardness than the transdental technique. Among the light sources, the LED showed greater hardness than the PAC; whereas, no significant differences between the QTH and other sources were detected. The mixed technique might improve the marginal adaptation of restorations, while not being detrimental to composite hardness.

Dye staining gap test: An alternative method for assessing marginal gap formation in composite restorations

Objective. The aim of this study was to evaluate and compare marginal adaptation of composite restorations assessed by a dye staining method and by scanning electron microscopy (SEM) analysis. Material and methods. Twenty bovine incisors were selected and ground flat to expose dentin. Two cylindrical cavities were prepared on the central area of flattened surfaces. Single bond adhesive system was applied in accordance with the manufacturer's instructions and the cavities were filled with Filtek Z250 or Filtek Flow. The specimens were polished and replicas were obtained in epoxy resin. The replicas were observed by SEM for marginal quality/quantity evaluation. Caries detector was then applied on each specimen for 5 s to verify marginal adaptation through dye staining of the formed gaps on the outer margins. Images of the stained gaps were transferred to a computer measurement program to determine gap length. The length of the gap was expressed as the percentage of total length of the margins observed. Data were submitted to two-way ANOVA and Pearson correlation. Results. Filtek flow showed 36% and 34% and Filtek Z250 27% and 29% of gap in the margins when evaluated by SEM analysis and by the dye staining test, respectively. There was no difference between the composites, regardless of the evaluation technique. There was a strong positive correlation (r=0.83) between the results obtained with the tested methods to assess marginal gap. Conclusion. Dye staining the gaps can be used with good reliability to evaluate the gap formation in composite restorations.

Flowable materials as an intermediate layer could improve the marginal and internal adaptation of composite restorations in Class-V-cavities

The purpose of this in vitro study was to evaluate the marginal and internal adaptation of restorative systems in combination with flowable materials as an intermediate layer in Class-V-cavities. Thirty Class-V-cavities with occlusal margins in enamel and gingival margins in dentin/cementum were prepared and randomly assigned to five groups. The following five restorative systems were used: compomer, composite E, flowable compomer/composite E, composite RF and flowable composite/composite RF. The flowable materials were added between the restorative composites and the cervical margins of the cavities. Marginal and internal adaptation were quantitatively evaluated before and after thermal (2,500 times between 5 and 55 degrees C) and mechanical load cycling (25,000 times 100 N) using standard SEM procedures. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U-Test. The morphology of the internal restorative interfaces was also evaluated. The present study revealed that the best marginal adaptation in dentin was attained with the compomer restoration (95.8% perfect margin). The marginal adaptation of composite restorative systems was improved by the use of a flowable compomer (45.5% vs. 68.2% perfect margin in dentin) or a flowable composite (46.7% vs. 80.7% perfect margin in dentin, p<0.05) as an intermediate layer. No differences were observed between the used materials for the parameter internal adaptation. In Class-V-cavities compomers showed the best marginal adaptation and the marginal adaptation of composite fillings could be improved by the use of flowable materials as an intermediate layer.

Association of photoactivation methods and low modulus liners on marginal adaptation of composite restorations

The aim of this study was to evaluate the effect of photoactivation methods, resin liners, and the association of these techniques on the marginal adaptation of composite restorations. One‐hundred‐and‐twenty bovine incisors were selected. A circular cavity was prepared in a flat dentin area on the buccal surface and the Scotchbond Multi Purpose system was applied. These teeth were assigned to four groups in accordance with lining technique: control (one adhesive layer), three adhesive layers individually photoactivated, Filtek Flow, and Protect Liner F. Each group was subdivided depending on the photoactivation method: continuous light, soft‐start, or intermittent light. All cavities were restored with Filtek Z250 and then polished. Caries detector was applied on each specimen for 5 s in order to verify marginal adaptation through dye‐staining of the gaps formed on the outer margins. Images of the stained gaps were observed under the stereomicroscope, and transferred to a computer measurement program in order to determine gap length. Data were submitted to ANOVA and Tukey's test (P < 0.05). Significant differences among the lining techniques were only observed using the photoactivation method with continuous light. In this case, the lining technique with Filtek Flow significantly increased marginal adaptation of the composite to the outer dentin margins compared with the results of the control group. The other lining techniques showed intermediate values and no statistical difference from the other groups. For the photoactivation methods, intermittent light showed the best marginal quality of all the methods. This was statistically significant only for the control lining technique.

Contraction stress and marginal adaptation of composite restorations in dentinal cavity.

The influence of contraction stress in composite resins on both the shear bond strength to dentin (BS) and marginal adaptation in a standardized dentin cavity was investigated using three restorative resin systems. A teflon ring mold (TF) or copper ring with a roughened inner surface (CP) placed on human tooth dentin was filled with the composite resin, and a shearing test was then performed. ANOVA of BS demonstrated a significant influence from the resin systems and type of molds. BSCP tended to be lower than BSTF in all three systems. This suggested that the inner surface of the CP restricted the flow of resin and then contraction stress occurred at the interface of the bond to the dentin. The system which demonstrated the smallest difference between BSTF and BSCP also showed the best adaptation. This result indicates that contraction stress in the composite resin plays an important role in marginal adaptation.

Long-term monitoring of microleakage of composites. Part I: Radiochemical diffusion technique

S everal studies have shown that microleakage is an important cause of bacterial contamination beneath composite restorations. Is3 A close relationship has been demonstrated between marginal adaptation of composite restorations and bacterial growth in cavities.4 These studies and others have demonstrated that pulpal inflammation under composite restorations is associated with microbial proliferation in the marginal gap around these restorations.5*6 Thus microbial microleakage has been recognized as an important factor in the biologic compatibility of resin-based restorations. The number and diversity of composite restorative materials available to the dentist has increased considerably in recent years.’ The factors controlling microleakage around such restorations are still largely unknown. This investigation used a previously described quantitative radiochemical diffusion technique to monitor the microleakage of three types of composite.*s9 A special aspect of this study was the influence of acid etching the enamel cavity walls. In part II of this report, a scanning electron microscopic evaluation was made of restorations to determine whether different composites affected the quality of tag formation against acid-etched enamel. The study also investigated the possibility of a relationship between resin tag formation and microleakage.”

Marginal adaptation of composite restorations performed in vivo with different acid-etch restorative procedures.

243 experimental Class V restorations using a chemically cured composite resin were inserted in human third molars with the conventional acid-etch restorative procedure and with eight modifications of this technique. The teeth were extracted following an observation period of 4 months. Sections from each cavity were stained and examined for bacteria on the cavity floor. Bacteria in more than 10% of the sections was used as the criterion for marginal leakage along a restoration. Results showed that non-composite resin applied as an intermediary layer in etched cavities or as a surface coating of immediately finished and re-etched restorations, beveling of the margins of preparations, and treatment of the etched cavities with the surface-active comonomer NPG-GMA before filling all significantly decrease the leakage occurrence in the oral environment. The observed differences between the modifications varied considerably but none of them was significant, and no additive effects were found.