Abstract
To have a grasp of the changes in lip pressure of cleft lip patients after cleft lip repair, is considered very important in predicting future jaw growth and the form of the dental arch.
The author previously reported on the chronological changes in the lip pressure at rest, the teeth, and the periodontal tissues in rhesus monkeys after an experimental labioplasty of the upper lip.
In the current study, the chronological changes in the lip pressure at mastication w ere examined using the same subjects ( 7 adult monkeys) and the- correlation between the lip pressure at rest and at mastication was studied. Th e results were as follows:
1) After the experime ntal labioplasty of the upper lip, the upper lip pressure at mastication increased remarkably but decreased gradually thereafter, and approximated the pre-operative pressure on the 30th day after operation.
2 ) The lower lip pressure, on the other hand, decreased slightly after operation. This decrease was due to a relaxing of the lower lip brought about by the labiOplasty of the upper lip. Thorelaxing was confirmed macroscopically. The pressure on the 15th day after operation approximated the pre-operative pressure.
3 ) The aforerentioned lip pressure at mastication showed a similar trend to that at rest as previously reported. However, the pressure at mastication was higher.
In view of the foregoing, cleft lip repair is consi dered to have some growth-restraining effect on the jaws and the form of dental arch in the early post-operative period. However, the repair is considered n ot to effect them after a certain period, as previously reported.
It was found that labioplasty of the upper lip will result in relaxation of the lower lip and cause shorttime regression to the pre-operative condition.
