Study of occlusal-articulation relationships with the help of T-SCAN apparatus.

UNLABELLED: Normal occlusal-articulation relationship between the two jaws ensure the even distribution of the occlusal forces during mastication. Data from the literature and the absence of serious studies evaluating the T-Scan apparatus give reasons for the present study. AIM: To evaluate T-SCAN apparatus for registration and analysis of occlusal contacts in dynamic articulation. MATERIALS AND METHODS: The study was carried out with the medical diagnostic apparatus T-SCAN. Out of 180 students (19-24 years old) examined, we selected 15 with intact dentitions without or with some small obturations and Angle class I relationship between the two jaws. Using T-SCAN we made 7 to 10 records in each of the studied students. RESULTS: The occlusal contacts are presented as two-dimensional and three-dimensional images of the contour with different size and colour depending on the force of the pressure. A model of the dental arch is superimposed over the registered occlusal contacts. The place of the centre of the force in central occlusion is determined. The trajectory of the centre of the force during movements of the mandible is recorded which allows determination of the direction and amplitude of movement of the mandible. CONCLUSION: The results from the study reveal that the correct use and analysis of the data from the apparatus T-SCAN provide valuable and reliable information for the localization and distribution of occlusal contacts in dynamic articulation.

Measurement of the magnitude of the occlusal forces during articulation.

INTRODUCTION: The magnitude and direction of occlusal forces are important factors for the balanced force load of the teeth during articulation. There are no studies available on the magnitude of the occlusal force in the literature. PURPOSE: To analyze the data from the apparatus T-SCAN in order to extend its possibilities in determining specific values of occlusal forces during the process of dynamic articulation. MATERIALS AND METHODS: The apparatus T-SCAN registers occlusal contacts with the help of a sensitive element (sensor) in a net of points. The apparatus scans all these points at specific intervals and depending on the magnitude of the force acting in each one of them enters a number in the range between 0-255 in the memory of the computer. The combination of the points coloured proportionately to the acting force in a given moment form one frame of the film of the occlusion. The sum of all occlusal forces acting in the contact points gives the total occlusal force. RESULTS: The apparatus with the program developed by us showed the following: 1. It shows in numerical and graphic mode the size of the total force of occlusal contacts as well as that one in the left and right half of the dentition or in another zone chosen by the dentist. 2. The size of the area of occlusal contacts is evaluated in a numeric or graphic mode. CONCLUSION: The data for the magnitude of the occlusal forces during the process of dynamic articulation provide valuable information about masticatory load on the teeth or prosthetic constructions. These data can be used in the diagnosis and prosthetic treatment.

Finite element tension analysis of the supporting tissues of a maxillary canine.

INTRODUCTION: The distribution of masticatory load on the teeth and the arising force tensions in them are factors that determine the origine of destructive processes in their periodontium. The development of mathematical models and application of new computer technologies make possible their precise study. They are still not thoroughly studied. PURPOSE: To study the tensions, originating in the periodontium of a canine tooth during occlusal load by the modern method of finite elements (MFE). MATERIALS AND METHODS: A three-dimensional model of a maxillary canine is built by MFE containing 304 finite elements with six varieties of geometrical form, linked in 1409 nodes. It is supposed that the tooth is fixed firmly to the outer surface of the periodontal membrane to the alveolar bone and is loaded in the lingual wall by a force perpendicular to its longitudinal axis and directed from the lingual to the vestibular wall. RESULTS: As a result of the calculations according to MFE the tension state of dental tissues is calculated for diferent degrees of destruction of the alveolar bone. It was established that with the increase of destruction of the alveolar bone for one and the same masticatory load, the tensions in the periodontal membrane also increase. The maximal tensions act in the apex of the root and around the clinical neck of the teeth. CONCLUSION: The results obtained provide precise information of distribution of force tensions in the periodontium of maxillary canines during occlusal load. They serve as a serious theoretical base for future investigations.