Journal of Applied Dental
and Medical Sciences
Journal of Applied Dental and Medical Sciences is A Quarterly Published


An In Vitro Study to Assess the Changes in Hardness and Tensile Bond Strength of Selected Soft Lining Materials, After Long Term Immersion in Denture Cleansers

Anumeha Narwal


One of the most clinical challenging issues in prosthodontics is hardening and debonding of soft liners from the denture base with time. Purpose: The purpose of present study was to assess the effect of two denture cleansers with different modes of action on the hardness and tensile bond strength of two autopolymerizing denture liners-one silicone based and one acrylic based bonded to denture base resin. Materials & Methods:420 test specimens were fabricated. out of which 210 were circular specimens (105 of each resilient liner) and were used for testing hardness. Other 210 fabricated specimens of heat cured PMMA were used for testing tensile bond strength after bonding it with two autopolymerizing resilient liners (105 of each silicone and acrylic based liners). Each group was further divided into seven subgroups of 15 specimens each, one to act as control and six were subjected to immersion in the two denture cleansers for different time intervals of 1 week, one month and six months. Hardness measurements of denture liners specimens (20x4mm) were done using Shore A Durometer and the tensile bond strength measurements of the specimens (10x10x83mm) using Universal Testing Machine. Results: Statistical analysis showed that immersion in denture cleansing solutions significantly decreased the tensile bond strength of the resilient liners to the denture base resin (P<0.01) and increased their hardness (P<0.01): and this increase was more in acrylic -based liners. Conclusion: It was concluded that within the limitations of this study, immersion in denture cleansers increases the hardness and decrease the tensile bond strength of lining materials bonded to denture base resin: irrespective of the type of denture cleanser used.

[Full Text Article]