Factors influencing proximal dental contact strengths.

The aim of this study was to systematically measure proximal contact strength in complete natural dentitions of 30 adults (25.3 +/- 3.0 years of age), and to analyze its relationship to tooth type, tooth location, chewing effort and time of day variation. The contact strengths were measured dynamically during removal of a calibrated 0.05-mm-thick metal strip between the proximal contacts of adjacent teeth. Proximal contact strengths were lower in the maxilla (2.51 +/- 1.36 N) compared to the mandible (4.26 +/- 1.88 N). Within the jaws, the lowest proximal contact strength was measured between canine and first premolar (2.91 +/- 1.79 N) and the highest between second premolar and first molar (3.73 +/- 1.95 N). Chewing increased the proximal contact strength within the maxilla (before: 2.51 +/- 1.36 N, after: 3.02 +/- 1.45 N) but it remained unchanged in the mandible (before: 4.26 +/- 1.88 N, after: 4.22 +/- 1.85 N). The proximal contact strength increased significantly from morning (3.39 +/- 1.86 N) to noon (3.61 +/- 1.77 N), and then decreased in the afternoon (3.43 +/- 1.60 N). It was concluded that proximal contact strength can be significantly influenced by location, tooth type, chewing and time of day variation. Based on the differences in distribution due to the effect of chewing and time of day, it is speculated that proximal contact strength is a physiological entity of multifactorial origin.