In vitro wear of denture teeth against human enamel

Denture teeth need to have sufficient wear-resistance in the partially edentulous patient with opposing natural teeth. 

Objectives: This study measures and compares the in vitro wear of denture teeth against human enamel. 

Methods: Mandibular molar denture teeth from 3 manufactures (see table) and extracted human teeth (control) were ground with a SiC polishing wheel to obtain a flat surface, polished with series of SiC abrasive papers (320/600/1200 grit) and finished with 0.05 µ alumina slurry and a polishing cloth. Specimens (n=8) were ultrasonically cleaned and mounted in acrylic in a brass holder. Each specimen was stored in distilled water at 37°C for 24 hours. Specimens were loaded into an Alabama Wear Testing Device. Cleansed extracted human bicuspids were prepared to obtain standardized cusps and used as antagonist styli. The specimens were subjected to 200,000 wear cycles (50N force and 72 cycles/sec). A solution of 50µm PMMA beads was used as media, simulating third-body food particles. The volumetric loss and wear depth of the denture and natural teeth were determined using a 3-D non-contact surface profilometer (Proscan 2000, Scantron, UK) and superimposition software (Proform, Scantron, UK). Data were analyzed using one-way ANOVA and Tukey's/Kramer post-hoc analysis (p=0.05).

Results: (Mean±SD)

Material	Volumetric wear (mm3)	Depth wear (µm)
Trubyte Portrait IPN (Dentsply)	0.249±0.09a	0.356±0.08a
Postaris DCL (Ivoclar)	0.206±0.11a	0.286±0.12a
Enamel	0.022±0.02b	0.045±0.02b

Groups with similar superscripts are statistically similar. All denture teeth showed more depth and volumetric wear than enamel. Conclusions: Denture teeth show significantly greater wear than enamel when opposing a natural tooth.