Orthopedic Protraction of the Maxilla in Macaca Speciosa

Abstract

The intent of this study was to use orthopedic forces to move the maxilla forward in Macaca speciosa (stump tailed monkeys). Three animals were fitted with helmets and facebows to serve as extraoral anchorage. Acrylic labial-lingual splints were ligated with wire around the maxillary teeth. Calibrated coil springs were placed between the splints and facebows and activated to produce forces of two, three, and four kilograms. Paired stainless steel implants had been placed to facilitate cephalometric analysis of the position of the maxilla. The period of activation was to have been thirty days. One animal escaped from the appliance within twelve hours. The other two were taken off the appliance within forty-eight hours because pressure necrosis had developed under the helmet. No data were collected. The uninjured animal was fitted with a different design of helmet and the spring was activated to produce one kilogram. After four days the animal had developed ulcers under the helmet and the experiment was terminated. Lateral headplates were taken before and after the experimental period. Cephalometric analysis and superpositioning showed no change in the position of the maxilla. It was concluded that after four days of one kilogram anterior pull the maxilla did not move. The difficulties encountered in the study defined the problem as being the attainment of suitable anchorage from which to apply the anterior orthopedic force to the maxilla. Several areas of additional research were discussed relative to achieving protraction of the maxilla.