Contribution of interdigitation to the occlusal development of the dentition in Macaca fascicularis

The contribution of interdigitation to the development of the dentition of juvenile Macaca fascicularis was studied on a series of dental casts and at the histological level by the use of vital staining. Fourteen laboratory-born monkeys were allocated to a control group (n = 7) or an experimental group (n = 7). They were followed from 31 to 152 weeks of age. In the animals of the experimental group, interdigitation was eliminated by gradually grinding the cusps of the molars and canines in both dental arches as soon as possible after emergence. Silicone impressions of the dental arches of each monkey were taken at regular intervals. Two experimental and two control animals received vital staining at regular intervals and were processed for histological evaluation at the end of the experimental period. Changes over time in the dimensions of the dentition were analysed. Locally, the maxillary dental arch in the experimental group broadened significantly faster than in the control group. No significant differences between the experimental and the control group were found for any of the mandibular parameters. The experimental intervention also led to less prevalence of anterior open bite in the experimental group than in the control group. It is concluded that interdigitation plays a role in the development of the maxillary dental arch and does not seem to affect mandibular dental arch development.