Bond Strength of composite repairs using flowable or conventional resins or the association of both

Raira Cruz Calamari,Graziela Ribeiro Batista,Taciana Marco Ferraz Caneppele,Carlos Rocha Gomes Torres,Natalia Cortez Gutierrez

doi:10.14295/bds.2012.v15i4.855

Abstract

Objectives: The aim of this in vitro study was to evaluate the effects of flowable resin as an intermediate agent on composite repairs on bond strength. Methods: Thirty truncated cones of Grandio SO (VOCO) were prepared and thermo-cycled for 5000 cycles for artificial aging. Specimen’s surface were sandblasted with aluminum oxide, cleaned with air/water spray and conditioned with phosphoric acid for 15s. After that, one coat of Admira Bond Adhesive (VOCO) was applied and light cured for 20s. Specimens were divided into 3 groups according to the repair material used (n= 10): Conventional Resin – Grandio SO (R), A thin layer of Flowable resin – Grandio SO Heavy Flow + conventional Resin (FR) and Flowable resin (F). Over the original specimens, a sectional cone-shape teflon matrix was hold in position , and the cones were built, according the groups described above. Another thirty specimens were built, 10 of each group, simulating a restoration without repair. Specimens were submitted to tensile stress in a universal testing machine. Data were recorded in MPa and evaluated with ANOVA, Tukey´ s and non-paired “t’’ tests. Results: ANOVA showed significant differences between groups which were performed repair (p< 0.00). The results of Tukey´ s test for these groups were: R (19.89 5.31)ab, F+R (14.49 5.59)a, F (20.91 3.99)b. The groups followed by the same letter did not show statistical differences. Non-paired “t” test showed that groups R and F repairs were similar of the correspondent groups which simulated a restoration without repair. Conclusions: The repair with conventional or flowable composite produced bond strength values similar to cohesive strength of the same materials. The use of a thin layer of flowable resin as an intermediate agent in composite repair decreased the bond strength when compared the same method for restoration.

Highlights

Over the last few decades, significant improvements have been made in the field of resin composites
The traditional treatment of defective composite resin restorations includes removing and replacing the whole restoration. This approach is often accompanied by removal of tooth structure, expanding the prepared cavity, increasing the loss of sound tooth structure [3]
The null hypothesis tested was that there is no significant difference between the use or not of flowable composites for repair of composite resin

Summary

Introduction

Over the last few decades, significant improvements have been made in the field of resin composites. The traditional treatment of defective composite resin restorations includes removing and replacing the whole restoration. This approach is often accompanied by removal of tooth structure, expanding the prepared cavity, increasing the loss of sound tooth structure [3]. The repair of defective composite is more conservative and might increase the longevity of the restoration, preserving sound tooth structure, and protecting the tooth from operative trauma [4]. This option is a more practical solution and allows the use of pre-existing restoration, if in acceptable condition [5]

Objectives

Methods

Conclusion