EVALUATION OF TENSILE BOND STRENGTH OF HEAT POLYMERISED ACRYLIC SOFT LINERS WITH VARIOUS SURFACE PRE–TREATMENT OF DENTURE BASES - AN IN VITRO STUDY

Abstract

Background and Objective:

Resilient liners are prone to bond failure with acrylic resin base, creating an environment for bacterial growth and accelerated break down of soft liner resulting in a deteriorating prosthesis. The purpose of this study is to evaluate the efficacy of mechanical, chemical and mechano-chemical pre-treatment of denture base resin on the tensile bond strength of heat cured permanent resilient liners.

Materials and Methods:

            A total of 320 cuboidal blocks (40x10x10mm) of heat-polymerised acrylic resin (Trevalon) were made which were equally grouped into Permasoft (Group-1) and Acrasoft (Group-2). Each group was further subdivided into four subgroups based on surface pre-treatment of denture base namely: Control, Chemical (Methyl methacrylate), Mechanical (sandblasting with 250 microns aluminum oxide particles), Mechano-chemical (sandblasting followed by Methyl methacrylate).  A 3mm thick resilient denture liner was packed between 2 resin blocks. Then, each subgroup was divided into two test groups (n=10) for testing tensile bond strength (using universal testing machine) after 24hrs and 30 days post immersion in artificial saliva. One-way ANOVA and Tukey test were used for data analysis.

Results:

The tests resulted in greater tensile bond strength for Acrasoft group compared to Permasoft at both 24hrs and 1 month. Between the two time periods, it was more for 24hrs group. Amongst all methods, mechanical method resulted in superior tensile bond strength.

Conclusion:

This in-vitro study concluded that all the tested pre-treatment methods showed better tensile bond strength than control group, maximum with mechanical group.

Key Words:

            Denture liners, pre-treatment, tensile bond strength