Marginal microleakage of cervical composite resin restorations bonded using etch-and-rinse and self-etch adhesives: two dimensional vs. three dimensional methods

Comparing the Ability of Various Resin-Based Composites and Techniques to Seal Margins in Class-II Cavities

Background: Resin-based composites (RBCs) provide excellent esthetics but the marginal micro-leakage in the proximal cavities remains a major concern. The aim of the present study was to assess the ability of various dental RBCs and techniques utilized for sealing deep dentin margin in class-II cavities. Methods: Box-cavities (class-II) on the distal and mesial surfaces of extracted (premolar) teeth were prepared with a gingival margin placed 1mm apical to the cemento-enamel junction. Teeth with prepared class II cavities were randomly divided into four study groups according to the type of restorative materials (conventional RBC; bulk-fill RBC; conventional RBC lined with flowable RBC and conventional RBC lined with resin-modified glass-ionomer-cement (GIC) as open sandwich-technique). Each group was further subdivided into a total-etch subgroup in which a separate etching step was performed before applying the bonding agent and a self-etch subgroup in which a self-etch adhesive system was used (n = 10). For each group, cavities were restored using the respective restorative materials and techniques, subjected to 1000 thermocycles, and placed in the methylene-blue dye. The specimen teeth were sectioned for further microscopic examination for micro-leakage. Results: The least dye penetration values were reported for group 4 (GIC) followed by the group Bulk-fill using the self-etch adhesive system (group 2b). The highest dye penetration was reported for the group Bulk-fill using the total-etch adhesive system (2a), followed by the group conventional RBC using the total-etch adhesive system). The total-etch adhesive system had significantly greater micro-leakage compared to the self-etch adhesive system (1a) (p = 0.026). Conclusions: The self-etch adhesive system significantly reduced the micro-leakage compared to the total-etch system. Bulk-fill RBC when bonded with the self-etch adhesive provided good marginal sealing ability comparable to open sandwich-technique using GIC.

Comparison of the Ability of Two Brands of CBCT with That of SEM to Detect the Marginal Leakage of Class V Composite Resin Restorations

Objectives

This study was carried out to compare the ability of two common brands of cone-beam computed tomography (CBCT), including New Tom and Planmeca, to detect the marginal leakage of class V composite resins. The ability of each of the two brands of CBCT to detect the marginal leakage of class V composite resins was also compared with that of scanning electron microscopy (SEM).

Methods

Class V cavities were prepared on the buccal surface of sixteen extracted caries-free human premolars. Cavities were conditioned and filled with composite resin. The teeth were immersed in 50% weight/weight aqueous silver nitrate solution for 24 hours. They were then taken out and rinsed with distilled water. Next, they were put in a developing solution. They were first viewed with New Tom and Planmeca CBCT units and were then sectioned and evaluated by an SEM.

Results

The results of the Wilcoxon signed-rank test showed no significant difference between the mean marginal leakage scores of New Tom and Planmeca CBCT images (p value = 0.157) and between those of New Tom CBCT and SEM images (p value = 0.098). However, there was a significant difference between the mean marginal leakage scores of Planmeca CBCT and SEM images (p value = 0.023).

Conclusion

There were no significant differences between New Tom and Planmeca CBCT units in the detection of marginal leakage of class V composite resins. However, when these CBCT units were compared with the SEM, the New Tom CBCT unit could detect the marginal leakage better than Planmeca.

Effect of different types of adhesive systems on the bond strength and marginal integrity of composite restorations in cavities prepared with the erbium laser-a systematic review

There are inconclusive results regarding etching and bonding protocol to achieve optimal bond strength and marginal integrity of adhesive composite resin restorations in erbium laser prepared cavities. This systematic review aimed to consider which adhesive system protocol may be optimal in achieving the bond strength and marginal integrity in erbium laser-prepared cavities, comparable to that obtained with conventional method of cavity preparation. This review was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement with literature search based on all publications during the period January1, 2000-October 10, 2020, in three databases: MEDLINE, Google Scholar and ScienceDirect. The necessary information was extracted by two independent authors. The search resulted in 139 articles from all databases, and a total of thirty-one articles met the inclusion criteria. The results indicated that the selection of adhesives depending on their pH and composition and the laser pulse duration and pulse energy used plays an important role in predicting the adhesion and marginal integrity. The 10-MDP containing moderate self-etch adhesives has demonstrated predictable outcomes. Longer pulse durations used for cavity preparations may indicate the use of etch-and-rinse (EnR) or moderate self-etch adhesives (SEA) to allow better resin infiltration in deep craters formed due to laser irradiation. However, further studies with more standardizations in relation to adhesives and laser parameters are needed.

Analysis of microleakage and marginal gap presented by new polymeric systems in class V restorations: An in vitro study

Objective

Evaluating the contraction of polymerization effect of silorane-based composite on dental interface in enamel.

Materials and Methods

Eighty class V cavities were confectioned in forty extracted molar teeth and restored with different combinations of resinous-based and bond system. They were divided into the following groups: (G1) three-step etch-and-rinse adhesive system and methacrylate-based resin, (G2) two-step etch-and-rinse adhesive system and methacrylate-based resin, (G3) Filtek P-90 self-conditioning adhesive system and methacrylate-based resin, (G4) Adper SE Plus self-conditioning adhesive system and methacrylate-based resin, (G5) three-step etch-and-rinse adhesive system and silorane-based resin, (G6) two-step etch-and-rinse adhesive system and silorane-based resin, (G7) Filtek P-90 self-conditioning adhesive system and silorane-based resin, (G8) Adper SE Plus self-conditioning adhesive system and silorane-based resin.

Results

Group 7 showed lower marginal leakage when compared with all other groups (p = 0.001).

Conclusions

The results allows suggesting that silorane-based resinous system is adequate to promote more satisfactory marginal sealing than any other combination, since the system is combined with its own bond system.

Evaluation of the effect of collagen stabilizing agents like chitosan and proanthocyanidin on the shear bond strength to dentin and microleakage of resin composite at enamel and cemental walls: An in vitro study

Objectives:

The objective is to evaluate the effect of collagen stabilizing agents-chitosan and proanthocyanidin (PA) on the shear bond strength to dentin and microleakage of resin composite at enamel and cemental walls.

Materials and Methods:

Thirty premolars were decoronated 2 mm above cemento-enamel junction and restored with composite resin. Teeth were then randomly divided into three groups: Group I - Control, Group II - Pre-treatment with chitosan, and Group III - Pre-treatment with PA. Samples were then subjected to thermocycling for 500 cycles at 5°C and 55°C with the dwell time of 30 s and transfer time of 5–10 s. Then, the samples were subjected to shear bond strength evaluation on Universal testing machine. Shear load was applied until failure occurred. The load to failure was recorded individually and statistical analysis was done. Microleakage was determined by methylene blue dye penetration method and subjected to stereomicroscopic evaluation. Statistical analysis was carried out using Mann–Whitney test and Chi-square test.

Results:

Group II specimens produced the highest median shear bond strength and group I showed the least. In addition, Group I, Group II, and Group III showed no statistically significant difference in microleakage.

Conclusions:

Application of Chitosan and PA improved the shear bond strength to dentin as compared to the control. However, no significant difference in shear bond strength and microleakage was found between them.

Hydrolysis-resistant and stress-buffering bifunctional polyurethane adhesive for durable dental composite restoration

A new elastic polyurethane (PU) adhesive was reported in this study to improve the stability and durability of the dental adhesion interface. A polyurethane oligomer was synthesized by the solution polymerization method, and a diluent and solvent were added to prepare PU adhesives. The water sorption, water solubility, contact angle, thermal stability, degree of conversion and mechanical properties of the PU adhesives were evaluated. Experimental applications for tooth restoration (microtensile bond strength and microleakage) were also performed, and cytotoxicity test was carried out. The water sorption and solubility of the PU adhesives were significantly lower than those of three commercial adhesives. The microtensile bond strength of the PU adhesives was improved after thermocycling test, and the extent of microleakage was diminished when compared with that of commercial adhesives. Biocompatibility testing demonstrated that the PU adhesive was non-toxic to L929 fibroblasts. This study shows the ability of PU adhesive to improve the stability and durability of the dental adhesion interface and may refocus the attention of scientists from rigid bonding to flexible bonding for dental adhesion, and it sheds light on a new strategy for the stable and durable bonding interface of dentine adhesives.

A comparison of the marginal and internal fit of porcelain laminate veneers fabricated by pressing and CAD-CAM milling and cemented with 2 different resin cements

STATEMENT OF PROBLEM

The marginal and internal adaptations of porcelain laminate veneers (PLVs) are key elements in their long-term success. However, the marginal and internal fit obtained with a pressable material compared with computer-aided design and computer-aided manufacturing (CAD-CAM) needs further investigation as does the choice of cement used.

PURPOSE

The purpose of this in vitro study was to evaluate the marginal and internal fit of PLVs fabricated using pressing and CAD-CAM milling and cemented using 2 types of composite resin cement.

MATERIAL AND METHODS

Twenty PLVs were fabricated from VITA PM9 pressable material, and 20 veneers were milled using VITA Blocs Mark II. Veneers were cemented to composite resin dies using either RelyX Veneer cement or Variolink-N cement. Specimens were embedded in clear resin and sectioned incisogingivally and mesiodistally. Marginal discrepancy at the incisal and cervical positions and the internal gap at 6 different locations were evaluated by using a scanning electron microscope. Two-way ANOVA followed by Tukey multiple comparisons were used to examine difference among groups (α=.05).

RESULTS

The cement and fabrication methods did not show any significant effect for absolute marginal gap (AMG) at the incisal edge, AMG at the cervical margin or marginal gap at the incisal edge. However, both had a significant effect on marginal gap at the cervical margin (P=.038 for the fabrication method and P=.050 for the cement used). Also, both cement and fabrication methods had a significant effect on internal gap average (P<.001). The lowest gap values were reported for veneers fabricated from VITA PM9 by using the press technique and cemented with RelyX Veneer cement. When the position of gap measurements was taken into consideration, it was the only significant factor (P<.001 for the effect of position on AMG and P<.001 for the effect of position on marginal gap). Gaps at the cervical position were significantly lower than gaps at the incisal position.

CONCLUSIONS

Smaller marginal and internal discrepancies were recorded for PLVs fabricated by using the pressing technique and cemented using RelyX Veneer cement compared with milled veneers and Variolink-N cement. Larger discrepancies were present incisally than cervically.