Abstract
The measurement of the oral cavity in dynamic conditions at the time of periodontal surgery was conducted for a total of 64 patients with periodontal disease ranging in age from 18 to 54 and the operative space was studied numerically. The results were as follows.
1) The mean width of the dental arch was 64.4mm in the upper jaw and 61.2mm in the lower jaw. The mean length of the dental arch was 54.6mm in the upper jaw 51.2mm in the lower jaw. The mean width and height of the palate were 38.1mm and 15.3mm, respectively.
2) When the mouth was opened naturally, i. e., without feeling fatigue, the same pause of the mouth could be maintained consciously for 15 to 20 minutes as an average. In this condition, the mean distance between the cutting edges of the upper and lower jaws was 44mm, the mean distance between the cusps of the second molar teeth was 25mm, the mean distance between the upper and lower lips was 34.5mm, the mean opening of the mouth was 42.7mm, and the mean internal circumference of the lips was 122.2mm with the mean space of 1, 088.7mm2.
3) In order to obtain an operative space in the vestibular fornix and the proper cavity, it is required to pull and expand the tongue and the buccal mucosa. The space thus obtained was 20mm in mean.
4) In the palatal gum, the mean height of the palate was 15.3mm, the mean length of the crown of the second molar teeth was 7.0mm and the mean distance between the cusps of the upper and lower third molar teeth was 25.0mm. However, in consideration of the floating of the tongue by 5.0mm in mean, the actual distance would be 20.0mm in mean. Consequently, the palatal space available would be the sum of these values, i. e., 42.3mm multiplied by the width of the palate 38.1mm.
5) The capacity of the operative field in the oral cavity as the mouth is opened naturally would be 20mm (space obtained by oppressing the tongue and the buccal mucosa)×42.3mm (mean space of the palatal region)×38.1mm (width of the palate).
6) Accordingly, maneuvers in periodontal surgery should be considered within the extent of such an operative field in the oral cavity as numerically descriebed above.
