The bond strength of the denture teeth to the polyamide denture base and the conventional heat cure acrylic denture base

Abstract

Objectives: To examine the debonding of the acrylic teeth to polyamide denture base under bending stresses, in comparison to that of the conventional heat cure acrylic denture base. Materials and Methods: Eighty maxillary central incisors were divided into two equal groups. Each tooth of Polyamide group was prepared with a “T-shaped connected tunnels”in the cingulam using a twist drill. Four wax blocks, having ten teeth each ware made and processed with polyamide base. For the acrylic group, four wax blocks having ten teeth each were prepared and processed with heat cure acrylic denture base. The blocks were mounted on the Instron universal testing machine, and increasing bending loads were applied at 135 degrees on the lingual side of each tooth using a 3 mm diameter rod until the tooth was de-bonded or the base was fractured. The results were statistically analyzed using Mann-Whitney U Test. Results: The mean bond strength of acrylic tooth to polyamide base was24.89Mpa. (load= 176N).There was no incidence of tooth debonding in the acrylic group. However, the heat cure acrylic base fractured at an average bending load of 316N (stress=44.7Mpa). Conclusion: Within the limitations, this study can provide the following conclusions: The polyamide denture base exhibited excellent fracture resistance, but the bond between the base and the tooth is significantly less than the fracture resistance of acrylic base. There is a significant risk of debonding of the tooth from the polyamide denture base. The bond strength of the acrylic tooth to the acrylic denture base is stronger than the toughness of the acrylic base.