2- 2- 4- The Bond Strength of the Denture Teeth to the Polyamide Denture Base And the Conventional Heat Cure Acrylic Denture Base



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