Abstract

Background & Objectives: Biocompatibility and bond to acrylic teeth constitute major requirement in choosing ideal denture base material. Hence, this in vitro study was intended to evaluate and compare bond strength of acrylic denture teeth to conventional heat cure and hypoallergenic denture base resin i.e. Group 1: Acrylic denture teeth bonded to conventional denture base resin (Trevalon). Group 2: Acrylic denture teeth bonded to hypoallergenic denture base resin (Sinomer®).

Method: A custom-made mould of brass was made to make wax cylinders of 6mm X 6mm dimensions. Molars from acrylic teeth mould (Premadent) were selected and there ridge lap surface were flattened with an acrylic trimmer and polished. Cleaned denture teeth surfaces were attached to wax patterns and were invested with Type III dental stone into Kavo metal flask and dewaxed. For GROUP 1 (Control) dewaxed Kavo metal flask was packed with conventional heat cure denture base resin in dough stage. For GROUP 2 (Experimental) dewaxed Kavo metal flask were packed with hypoallergenic denture base resin. Each one of the tested materials was cured according to the manufacturer’s instructions. After curing, specimens were retrieved and finished and polished.

To measure bond strength, each specimen was embedded in autopolymerizing resin to transfer it to mounting jig of Universal Testing Machine. After embedding, the specimen was stored in water at room temperature for 4 weeks before testing and all specimens were tested on the same day at room temperature. The acrylic resin blocks were held on mounting jig and force was applied parallel to the bonding surface at tooth-base interface. Amount of force at fracture will be recorded in Newton (N) and maximum stress will be recorded in Mega Pascals.

Results: The data obtained from the study were tabulated and subjected to statistical analysis using Unpaired ‘t’ test to compare flexural strength between control and experimental groups.

Intergroup comparisons yielded a significant difference of mean bond strength between group 1 (21.20±1.21) and group 2 (15.05±0.73). This suggested, the greater bond strengths for heat polymerized specimens. In all groups most of the failures were of the adhesive type.

Interpretation & Conclusion: Within the limitations of the study, it was concluded that overall, significantly higher shear bond strength to the denture teeth tested were obtained with conventional heat polymerized denture base resin rather than hypoallergenic Alldent Sinomer® denture base resin and in all groups most of the failures were of the adhesive type. Mechanical retentive aids are required for hypoallergenic Alldent Sinomer® denture base resin for stronger bonding with denture teeth as instructed by manufacturer.

Keywords: Denture Base material, Hypoallergenic denture base resin, tooth bond strength, Sinomer.