AN IN-VITRO WEAR STUDY OF DENTAL PORCELAINS AND HUMAN ENAMEL / 대한치과보철학회지

ABSTRACT

Dental porcelain is one of the materials of choice for restoration where esthetics is of concern, but has a considerable potentials of wear. The wear of enamel is variable when opposed by different porcelain systems and surface conditions, and the exposed dentine and opaque porcelain due to clinical failure is expected to have high potentials of wear. The purpose of this study was to investigate the wear effects of self-glazed, polished incisal porcelain, polished dentine and opaque porcelain against human enamel in the laboratory by use of a pin-on-disk type wear tester. 4 types of dental porcelain(Vita-omega, Ceramco-II, Vintage powder, Vita-alpha of In-Ceram system) and type IV gold alloy as cotrol group were used for test specimens. Intact buccal cusps of maxillary premolar were used for enamel specimens, and the cusp converged to a point and was devoid of visible abrasion, caries, decalcification. The upper part was the cusp of a maxillary premolar and the lower part was a porcelain specimen. The enamel wear was determined by weighing the cusp before and after each test. Surface profilometer was used to quantitate wear of the porcelain specimens. Vicker's hardness tester was used to evaluate the surface hardness of test specimens. The SEM was used to evaluate the wear surfaces. The results were as follows 1.Self-glazed porcelain produced more enamel wear than polished porcelain, especially the enamel wear of Vita-alpha self-glazed porcelain was 3.2 times more than that of other groups. 2.Opaque porcelain produced least porcelain wear, Vita-alpha self-glazed porcelain produce greatest porcelain wear, but there was no statistically significant difference between the groups(p>0.05). 3.The enamel wear of dentine porcelain was 3.8 times more than that of polished inisal porcelain(p0.05). 4.Overglazed porcelain produced less enamel wear than self-glazed porcelain, and more enamel wear than polished porcelain, but there was no statistically significant difference between the groups(p>0.05). 5.The hardness number of Vita-omega dentine and Ceramco-II opaque porcelain was larger, but that of Vintage dentine and Vita-alpha self-glazed porcelain was similar to other groups. 6.Examination of SEM photographs revealed that overglazed porcelain had smoother surface than self-glazed porcelain, and self-glazed porcelain had smoother surface than polished porcelain. Much polishing scratches and larger porosities were observed on the opaque porcelain specimen, and much polishing scratchess and small porosities were observed on the dentine porcelain specimen.