Craniofacial growth after a period of unilateral masticatory function in young rabbits.

Changes in craniofacial growth after a period of unilateral masticatory function were studied in rabbits. 10-day-old animals were divided into 3 groups. In Group I, mandibular and maxillary molars were ground down 2x a week on the right side under general anesthesia until age 50 days, and were thereafter left to grow without grinding. In Group II, the right-side molars were ground until age 40 days on. Between days 40 and 60, grinding was performed on the left side. The animals were thereafter left to grow. Group III consisted of unoperated control animals. All of the animals were fed whole pellets and water ad libitum, and were sacrificed at age 100 days. There were measurable differences in growth after periods of unilateral masticatory function. The mandibular ramus was higher, the condylar processus was larger sagittally, and angles between the anterior or posterior borders of the condylar process and inferior border of mandible were smaller in the treated than in the control animals, and there were differences between right and left sides of the same animal in the maxilla and mandible. The inclination of the articular surface of the glenoid fossa was steeper anteriorly on both sides in the treated than in the controls. It was concluded that growth after a period of unilateral masticatory function in young rabbits does not rectify all of the asymmetric changes in the maxilla, mandible and glenoid fossa resulting from the asymmetric function.