Histocompatibility of Thermopolymerized Denture Base Copolymer Processed with a Novel Ring-opening Oxaspiro Comonomer: A Histomorphometric Investigation in Rats

Abstract

Aim and objective: The aim of the research was to evaluate the histocompatibility of thermopolymerized (TP) novel denture copolymer containing 3,9-dimethylene-1,5,7,11-tetraoxaspiro[5,5]undecane (DMTOSU) comonomer in rats' palatine tissue.

Materials and methods: The rats were randomly categorized into four groups (n = 6 per group). G_CW: Denture base appliance (DBA) fabricated by short polymerization cycle in a water bath without DMTOSU; G_TW: DBA with 20 wt.% DMTOSU polymerized at 70°C for 2 hours followed by short polymerization cycle in a water bath; G_TA: DBA with 20 wt.% DMTOSU polymerized at 60°C for 45 minutes followed by 130°C for 20 minutes in an autoclave; and Group NC (negative control): rats with no DBA. The rats were euthanized after 2 weeks and the palatal tissues were subjected to histological examination. Epithelial thickness (ET), connective tissue thickness (CT), and keratin layer thickness (KT) were measured.

Results: G_CW exhibited greater ET, CT, and KT than the other groups. The ET and KT of G_TA were significantly lesser than G_TW. Multiple comparisons exhibited significant differences between the groups, except for G_TW and G_TA concerning the CT.

Conclusion: The novel denture copolymer containing 20 wt.% of DMTOSU comonomer is histocompatible with rats' palatine tissue.

Clinical significance: As DMTOSU is a double-ring-opening antishrinking oxaspiro monomer, its incorporation in TP-DBR would result in dimensionally accurate and stable dentures without endangering the biocompatibility in the prospective years.

Keywords: Comonomer; Denture; Histocompatibility; Initiation Ring-opening..