Packable Composite Restorations Research Articles

EFFECT OF DIFFERENT CAVITY LINING MATERIALS ON MARGINAL SEALING OF PACKABLE COMPOSITE RESIN RESTORATIONS- AN IN VITRO STUDY.

ABSTRACT:
 “AIM: To assess the effect of three lining materials; flowable composite, flowable compomer, and light-curing glass ionomer cement (LCGIC) on microleakage in Class V restoration using packable composite restorations.
 MATERIALS AND METHODS: A standardized class V cavity was prepared on buccal surface of 40 young premolar teeth with the cervical margin extending 0.5 mm below the cementoenamel junction, into the dentin. All the samples were randomly divided into 4 groups according to the lining material used: Group I- Control; Group II- flowable composite; Group III- LCGIC and Group IV- flowable compomer. The restored teeth were thermocycled and immersed in 2% methylene blue solution for 24 hours. Each tooth was then sectioned along buccolingual direction. The dye penetration of the occlusal and gingival margins of each section was evaluated by a single observer using a stereomicroscope and statistically analyzed using Kruskal Walis Test and Mann-Whitney U Test.
 RESULT: Maximum dye penetration score for Group 1, Group 2 was 3 and Group 3, Group 4 was 1. (p<0.05)
 CONCLUSION: Flowable compomer and light cure glass ionomer cement as intermediate lining material can reduce microleakage under packable composite.
 Keywords: Compomer, flowable composite, light-curing glass ionomer cement, microleakage, packable composite.”

Evaluation of Microleakage in Class II Cavities using Packable Composite Restorations with and without use of Liners.

The advent of the esthetic era and advances in adhesive technology saw the emergence of resin composite materials. But the problem of polymerization shrinkage remained. This was due to the contraction of the resin during curing inducing internal and interfacial stresses at the tooth restoration interface, leading to gap formation and subsequent micro-leakage. A number of techniques and modifications in the material have been proposed to minimize polymerization shrinkage and microleakage. In this study, the hypothesis that the placement of resin-modified glass ionomer cement (RMGIC) or flowable composite, as liner, beneath the packable composite, on the gingival surface of the tooth [coronal or apical to cementoenamel junction (CEJ)], could reduce the microleakage in class II composite restorations, was tested. Sixty recently extracted noncarious human mandibular molars were used. The teeth were randomly divided into three groups (20 specimens each): Group I (Filtek P60 with RMGIC liner), group II (Filtek P60 with Filtek Z350 liner) and Group III (Filtek P60 without liner). The teeth of each group were further subdivided into two subgroups (equal number of cavities). Subgroup A gingival seat 1 mm occlusal to CEJ on mesial side. Subgroup B gingival seat 1 mm apical to CEJ on distal side. It was concluded that in class II composite restorations gingival microleakage is more at the dentinal surface than on enamel. The use of a flowable composite and RMGIC, as liners, beneath the packable composite, in class II composite restorations, significantly reduces the microleakage when margins are in dentin, but the reverse is true, when the margins are in enamel.How to cite this article: Arora R, Kapur R, Sibal N, Juneja S. Evaluation of Microleakage in Class II Cavities using Packable Composite Restorations with and without use of Liners. Int J Clin Pediatr Dent 2012;5(3):178-184.

Six-year Clinical Evaluation of Packable Composite Restorations

For decades, resin composites have been used with increasing frequency as posterior restorative materials, because of the demand for aesthetic restoration. This study evaluated the six-year clinical performance of Filtek P60 (3M ESPE) packable composite restorations in combination with a one-bottle etch and rinse adhesive, Single Bond (3M ESPE), in Class II restorations. A total of 47 restorations were placed in the Class II cavity preparations (27 premolars and 20 molars) of 33 patients (22 female/11 male; mean age 34) by the same operator. The restorations were evaluated by two examiners at baseline and 1, 2, 3 and 6 years according to the method developed by Ryge, which also is known as the United States Public Health Service (USPHS) criteria. The following characteristics were observed: marginal adaptation, anatomical form, surface texture, marginal discoloration, surface staining, post-operative sensitivity and secondary caries. The Chi-square and Wilcoxon signed rank test with Bonferroni adjustment were used for statistical analysis (p = 0.05). All the restorations received Alpha scores at baseline assessment, except for one restoration, which showed post-operative sensitivity. At the three-year recall examination, two patients, with a total of three restorations, were not included. From baseline to three years, only two of the 44 restorations changed from Alpha to Bravo, for numerous reasons. At the six-year recall, 44 restorations were available for examination. The majority of restorations exhibited Alpha or Bravo scores for the evaluated criteria. No significant differences were found for any of the clinical criteria (p > 0.05). Only two restorations needed to be repaired due to caries that began independently from the restorations. Three or four restorations showed slight surface staining and marginal discoloration. The clinical performance of the posterior composite restorations that were evaluated was acceptable after six years of service.

The effect of an intermediate layer of flowable composite resin on microleakage in packable composite restorations

The aim of the present study was to evaluate the effect of a thin layer of flowable composite on microleakage in Class II direct packable composite resin restorations on young permanent teeth in vitro. Twenty sound human premolars and molars extracted for orthodontic reasons were selected for this study. The teeth were randomly assigned into two groups of 10 teeth each (groups A and B). Class II cavities were prepared as uniformly as possible in the mesial and distal aspects of each tooth. The gingival margin extended apically approximately 0.5 mm beyond the cemento-enamel junction, in the dentin. Cavities in group A were restored with packable composite and Alert/Flow-it flowable composite, while groups B cavities were restored with Pyramid/Aeliteflo. The control cavities in groups A1 and B1 were restored with only packable composite. The teeth were immersed in 2% methylene blue solution for 24 h to allow dye penetration into possible existing gaps between the tooth substance and the restorative material. All teeth were subjected to thermocycling. The dye penetration ranged between 6.6 and 7.2 mm. No significant difference was found between the control and the experimental groups. The use of flowable composite resin as intermediate material does not reduce microleakage.

Fracture resistance of class II packable composite restorations with and without flowable liners

This study evaluated fracture resistance in class II slot packable composite restorations with and without the use of a flowable composite liner. A conventional microhybrid composite was used as a control. Thirty-six sound, caries-free human mandibulary molar teeth were used. Separate mesio-occlusal and disto-occlusal class II slot cavity preparations were made in each tooth. The prepared teeth were randomly divided into three groups of 12 teeth. Two packable composites (Surefil, Filtek P60) and one microhybrid composite (Filtek Z250) with their respective manufacturer's bonding agents were used to restore the cavities. One side of each tooth was restored with composite alone, while the other side was restored with the composite lined with that manufacturer's flowable liner. The marginal ridges of the restorations were loaded at an angle of 13.5 degrees to the long-axis of the tooth in an Instron Testing Machine until failure. The data were analysed using a one-way anova. There was no significant difference in fracture resistance between composite restorations with and without flowable liners.

Microleakage of posterior packable composite resin at the gingival margins of class II cavities

The use of flowable composite resins as liners in class II packable composite restoration has been suggested by some manufacturers. However, the contributions of this technique are unproven. The purpose of this study was to compare the gingival microleakage in class II packable composite restorations with or without the use of flowable composite resins as liners. Slot cavities were prepared on both proximals of 80 extracted human molars and randomly assigned to 8 groups of 20 each. The gingival margins were located at 1mm above CEJ in 80 cavities (group1-4) and 1mm below CEJ in 80 cavities (group5-8). The prepared teeth were mounted in the customized tray with adjacent teeth to simulate clinical conditions and metallic matrix band (Sectional matrix) and wooden wedges were applied. After acid etching and application of Single Bond, each group was restored with the following materials using incremental placement technique: Group 1,5 (Filtek P60), group 2, 3, 4 and group 6, 7, 8 (AeliteFlo, TetricFlow, Revolution/ Filtek P60). All specimens were thermocycled 500 times between 5 and 55 with 1 mimute dwell time, immersed 2% methylene blue dye for 24 hours and then rinsed with tab water. The specimens were embedded in clear resin and sectioned longitudinally through the center of restoration with a low speed diamond saw. Dye penetration at gingival margin was viewed at 20 magnification and analyzed on a scale of 0 to 4. Kruscal-Wallis One way analysis and Mann-Whitney Rank sum test were used to analyze the results. The results of this study were as follows. 1. The leakage values seen at the enamel margin were significantly lower than those seen at the dentin margin(P0.05). 3. On the dentin margin, four groups demonstrated moderate to severe leakage, and there were no significant differences in leakage values(P>0.05).