The Reliability of a New Device for Measuring the Proximal Contact Strength

Objectives: To test the inter- and intra-examiner reliability of a recently developed instrument for measuring the proximal contact strength (Tooth Pressure Meter: TPM). To measure proximal contact strength, the frictional forces at removal of a straight 0.05 mm thick metal matrix band inserted between adjacent teeth were recorded. Custom-written software in Excel (MS Office) was used for the construction of diagrams relating the force (N) to seconds (s). Methods: Ten healthy adults with complete dentition and no signs of periodontitis or caries volunteered in this study. All contacts between the canine and the second molar were measured from mesial to distal either in the upper right and lower left or in the upper left and lower right quadrant. The order was randomly selected. Without any prior calibration, the investigators measured all contact strengths within one hour in alternate order two times (T1 and T2) each. The sequence of the investigators was randomly given as well. The standard deviations of the single measurements between the first and the second measurement separately for both investigators were taken as intra-examiner reliability, the standard deviations of the single measurements between the two examiners at the first and second measurement were taken as inter-examiner reliability. Results: The intra-examiner reliability was 0.33±0.28 N for one and 0.36±0.31 N for the other investigator (n.s.; Wilcoxon test for paired samples). The inter-examiner reliability at T1 was 0.47±0.42 N and at T2 0.36±0.35 N (p=0.04). Conclusions: It is concluded that the TPM produced reliable results. The reduction of the inter-examiner reliability between T1 and T2 indicates, that calibration is necessary to generate more reproducible results. Keywords: proximal contact strenth, tooth pressure meter