Evaluation of Disocclusion During Protrusive and Laterotrusive Movements

Introduction The importance of disocclusion in maintaining the health of the stomatognathic system is well established. However, the quantification of the same is limited. This study aimed to determine the amount of posterior teeth disocclusion in protrusive and laterotrusive movements to establish the desired disocclusion in occlusal treatments. Materials and methods Twenty dentate subjects with Angles Class I occlusion, 18-30 years, were included in the study. Direct and indirect techniques measured disocclusion at the mesiobuccal cusp tip of the mandibular first molar. In the direct technique, the protrusive and working and nonworking records were made intraorally at the edge-to-edge position of maxillary and mandibular central incisors and canines, respectively. For the indirect technique, putty indices were made on a semi-adjustable articulator at 2 millimeters (mm) eccentric movements and the disocclusion records were then made intraorally using indices at the predetermined excursions. The records were trimmed, and the disocclusion was measured using an optical microscope (ZEISS Axio Imager 2; Carl Zeiss Microscopy Deutschland GmbH, Oberkochen, Germany). The comparison of disocclusion by both techniques was done by paired t-test. The Pearson correlation coefficient was used to analyze the statistical correlation between the disocclusion obtained during different excursive movements. Results The mean disocclusion obtained by direct technique was 1.72 ± .49 mm in protrusion, 1.19 ± .50 mm for the working side, and 2.54 ± .70 mm for the nonworking side. For the indirect technique, the disocclusion obtained was 1.22 ± .37 mm in protrusion, 8.57 ± .33 mm for the working side, and 1.71 ± .61 mm for the nonworking side. On comparison, there was a statistically significant difference (p<0.05) seen for the values between the groups for direct and indirect subgroups except for the left working subgroup (p>0.05) with higher values in the direct group. Conclusions The disocclusion obtained by the direct technique was higher than that obtained by the indirect technique. For both techniques, as the working side disocclusion increased, the nonworking side disocclusion also increased.