Comparison of proximal contact tightness between implant and natural teeth

Objectives: The aim of this study was to evaluate the TPTC using a novel device in a resting state on implant prostheses and natural teeth.

Materials and methods: (1) TPTC between the natural teeth. Ten healthy young adults with class I normal occlusion consented to participate in the study. (2) TPTC between the natural tooth and implant prosthesis: This group was comprised of 20 patients, restored with a total of 20 single-implant crowns in the left maxillary and mandibular second molars for 10 single-implant crowns, respectively. All implants were longer than 11.5 mm and had a diameter of 4.0 mm. All abutments were screw-retained UCLA gold (hexed) abutments. All superstructures were gold-alloy full cast crowns. All subjects had a natural interproximal tooth surface between the left first molar and the implant prosthesis in both the maxilla and mandible. Test areas were divided into 4 groups. UM describes the contact between the upper natural left first molar and natural second molar; LM the contact between the lower natural left first molar and natural second molar; IUM the contact between the upper natural left first molar and implant second molar; and ILM the contact between the lower natural left first molar and implant second molar. The TPTC was measured at a resting state in each area. One-way ANOVA was used to compare the values in each group.

Results: The mean TPTCs of the UM, LM, IUM, and ILM were 1.48 (± 0.44) N, 1.78 (± 0.40) N, 1.14 (± 0.37) N, and 1.30 (± 0.32) N, respectively. There was a statistically significant difference in TPTC between LM and IUM (p < 0.01), and between LM and ILM (p < 0.05).

Conclusions: The quantitative evaluation of the TPTC on implant prostheses was attempted with the use of a newly developed device. Results indicated that the TPTC was less between the natural tooth and the implant prosthesis than between natural teeth.