Date of Award
Master of Science (MS)
Purpose: In full mouth reconstructive dentistry, the occlusal vertical dimension(OVD) is often increased to provide adequate restorative space or for esthetic reasons. The purpose of this study was to analyze the effect of occlusal vertical dimension on dimensional measurements of the smile.
Materials and Methods: 30 dental students, 12 male and 18 female between the ages of 21 - 30 participated in this study. Polyvinyl Siloxane bite splints of 2mm, 4mm, 6mm, 8mm thicknesses were fabricated on stone casts mounted on semi-adjustable articulators. A wall-mounted head positioning device, modified from a cephalometric unit was used to stabilize head positions. Three photographs each at OVD of +0mm, +2mm, +4mm, +6mm, +8mm were taken using a DSLR camera mounted on a tripod. Measurements were made in Adobe Photoshop CS5, using the width of the maxillary central incisors to convert pixel measurements to millimeter measurements.
Results: One way repeated measures ANOVA found statistically significant differences in interlabial gap height, incisal edge - lower lip length, and display zone area with increasing OVD. No statistically significant differences were found for intercommisural width and incisal edge - upper lip length.
Conclusions: This study demonstrates that excessive increase of OVD may lead to excessive interlabial gap height, incisal edge - lower lip length, and display zone area. A lengthening of the upper lip at smile should not be expected with increasing OVD. In addition, a change in the width of the smile should not be expected with increasing OVD.