Wear of Hydroxyapatite Sliding Against Glass-Infiltrated Alumina

Published

January 1, 2003

Author(s)

Sergei Kalinin, B Hockey, S Jahanmir

Abstract

The present work reports on the processes involved in the wear of hydroxyapatite sliding against slip-cast, glass-infiltrated alumina. Synthetic hydroxyapatite is used as a model material representing tooth enamel, while the alumina that was used is designed for tooth restorations. The wear tests were conducted in distilled water using a pin-on-disk tribometer under contact conditions that mimic the oral environment. Both wear surfaces were examined by SEM, AFM, EDS, and TEM to discern the wear process for this material system. Wear tracks on glass-infiltrated alumina showed only minor damage consisting of removal of glass from intergranular pockets in this material. In contrast, the hydroxyapatite wear surfaces were covered by an adhered debris layer, which obscured the rough, underlying surface. Hydroxyapatite fragments consisting of both single crystals and polycrystalline particles, presumably produced by fracture and deformation processes, were found in the TEM examination of this debris layer. TEM examination of the debris layer also revealed the presence of porous amorphous particulates containing Ca, P, O as major elements and Al and La as minor constituents. The composition of this amorphous wear product suggests a tribochemical reaction of hydroxyapaptite and infiltrated alumina with water. The wear process, therefore, consists of material removal by fracture and deformation of the hydroxyapatite, followed by mixing of the crystalline fragments with the reaction products and the glass-infiltrate to form a uniform debris layer on the hydroxyapatite wear surface. The effects of this surface layer on wear are considered to include moderation of the local contact stresses and control of the immediate environment under which wear occurs. Our wear data, represented in terms of the wear factor, is found to be consistent with published data on the wear of tooth enamel sliding against different types of ceramic restorations.

Citation

Journal of Materials Research

Volume

18

Issue

Iss. 1

Pub Type

Journals

Keywords

alumina, ceramics, dental restoration, hydroxyapatite, sental materials, teeth enamel, wear

Citation

Kalinin, S. , Hockey, B. and Jahanmir, S. (2003), Wear of Hydroxyapatite Sliding Against Glass-Infiltrated Alumina, Journal of Materials Research (Accessed April 26, 2024)