The shear bond strength of artificial teeth with denture bases

A.F. Hatoor, Nabeel; N.A. Ali, Hussain.

	The shear bond strength of artificial teeth with denture bases
Journal of baghdad college of dentistry
Article 1, Volume 22, Issue 2, 2010, Pages 32-37
Authors
Nabeel A.F. Hatoor; Hussain. N.A. Ali
Abstract
ABSTRACTBackground: Fracture and deboning of artificial teeth from denture bases are common clinical problems which arefacing both the patient and the dentist. The optimal combination of artificial teeth with visible light cured (VLC)denture base resin and the effect of thermocycling should be evaluated. This study was conducted to evaluate andcompare the shear bond strength of artificial teeth (acrylic and porcelain) with denture bases cured by water bathand visible light under the effect of different surface treatments and the effect of thermocycling with artificial saliva.Material and methods. Heat polymerized (Densply) and visible light polymerized (Elite) acrylic resins were used. Twotypes of artificial teeth (acrylic, Florident) and (porcelain, Ivoclar vivadent) were prepared. Five specimens of eachtooth type were processed to each of the denture base materials after the application of different surfacetreatments according to the manufacturer’s instructions. Five specimens for each type of artificial teeth withoutsurface treatments were also fabricated. Specimens were thermocycled and tested for strength until fracture with anInstron universal testing machine. Data were analyzed with analysis of variance and student T-test. Aphotomicrographic microscope was used to identify adhesive and cohesive failures within debonded specimens.Results. The mean force required to fracture the specimens were obviously larger for heat cured specimenscompared with the light cured specimens. The most common failure was cohesive within the tooth or the denturebase. With each base material, the artificial teeth which were treated with combined mechanical and chemicalsurface treatment exhibited the highest shear bond strength. Thermocyclig had deleterious effect on the light curedspecimens. In general, heat polymerized groups failed cohesively within the artificial tooth. While the light curedgroups failed adhesively at the tooth denture base interface.Conclusions. Within the limitations of this study, the type of denture base materials and surface treatments of thedenture tooth selected for use may influence the shear bond strength of the tooth to the base. Selection of morecompatible combinations of base and artificial teeth may reduce the number of prosthesis fractures and resultantrepairs.Key words: acrylic teeth, porcelain teeth, visible light cured denture base, thermocycling, acetone, thinner,hydrofluoric acid, shear bond strength. (J Bagh Coll Dentistry 2010;22(2):32-37).

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