Topographic distribution of occlusal contacts of the first mandibular molar--comparative study

The specification of the occlusal contacts in the posterior teeth region is a necessary clinical reference point for creating optimal interrelations between the teeth and dentition. The methods, such as the photo-occlusal method, the quasiplanimetric method, two-phase proof imprint in central occlusion, recording of contacts with profile wax, that have been used in studying the number and location of occlusal contacts at various positions of the mandible in relation to the maxilla are exact but difficult to apply clinically. The purpose of the present study is to find the topographic distribution of occlusal contacts in intact first mandibular molars using a method that is easy to utilise clinically and to compare the present results with the findings of the authors. The masticatory teeth of 100 high-school students (18 years old) without subjective complaints or objective structural or functional disorders of the temporomandibular joint were studied by means of articulation paper. From that sample 41 students with intact dentition and orthognathic occlusion were selected. The first mandibular molars (N = 77) were studied. The results are as follows. The occlusal contacts in the first mandibular molar vary from 1 to 7. The greatest percentage of contacts is observed in the tubercles. In the first mandibular molar the biting pressure upon the tubercle apex areas is greater compared to that on the sloping areas. Our results were compared with the findings obtained by the other three methods mentioned above. Our method allows objective specification of the topographic distribution of occlusal contacts.