DEPARTMENT OF REVIEWS AND ABSTRACTS

Edited by

T. M. Graber, D.M.D., Ph.D. Kenilworth, Ill.

All inquiries regarding information on reviews and abstracts should be directed to the respective authors. Articles or books for review in this department should be addressed to Dr. T. M. Graber, 4.50 Green Bay Road, Kenilwo’r:th, Illinois 60043.

Thesis abstracts

Transverse Growth Changes in the Rabbit Maxilla Utilizing Vestibular Shields Luka Popovic Case Western Reserve University, Cleveland, 1981

Recent clinical use of vestibular shields in the Frankel functional appliance has stimu- lated interest in the claims that there is a direct cause-effect relationship in their use and the increase in the transverse maxillary dental arch dimension.

The purpose of this study was to assess morphogenic and histogenic effects of buccal shields on maxillary width, using a New Zealand white rabbit laboratory model.

Five actively growing animals had buccal shield appliances fixated by circumzygoma- tic wiring for 35 days. These animals were compared to a sham control group of three animals of similar age. Several categories of data, including plaster casts, skeletal growth changes, histologic sections, etc., were collected.

Histologic sections did not provide evidence of any remodeling differences in regional alveolar and palatal changes between experimental and control groups.

Cast measurements suggest a maintenance of normal dental arch increases in those regions contiguous to the shields and protected fron buccal musculature effect. Regions distal to the maxillary second premolar, not protected by shields, showed actual reduction of the transverse dental arch dimension.

Feeding interferences caused by the appliance apparently caused gross differences in over-all body and skeletal development. Cephalometric analysis suggested that retarded body growth affects maxillary and basicranial maturation loss than postcranial regions.

The study suggests that normal skeletal relationships between the maxilla and its counterpart, the anterior cranial fossa, cannot be altered beyond prescribed growth boun- daries by means of the vestibular shields, as used in this study. However, results obtained did demonstrate increased maxillary transverse dimensions. But future studies should attempt to design an experimental model which does not produce severe growth retarda- tion between treatment and control groups.

447