Digital mapping of the interocclusal distance during biting by image processing of occlusal registration

Changes in occlusal contacts between the surfaces of upper and lower dentitions during biting are associated with masticatory function. This study was designed to establish a new method for measuring the inter-occlusal distance that is capable of digital mapping of the inter-occlusal distance along the surfaces of the tooth cusps. Commercially available computer programs for image processing were used. An occlusal record was made using a black silicone rubber impression material and image of the occlusal registration was made with scanner. The image was digitized and standard thickness records were used to obtain relation between gray scales of the image and the thickness. Differences in the gray scale for the interval of 20 μm (50 μm, 70 μm, 90 μm, 110 μm, 130 μm and 150 μm) were detectable. The contact and near contact areas recorded in vertical tooth clenching at 50% muscle activation clearly differed from those in 100% muscle activation. The changes in the map of inter-occlusal distance may indicate features of occlusal force transmission along the dental arch that are dependent on each individual´s occlusion. This method has the potential to be a powerful tool in the study of human jaw biomechanics.