Palatal implants in adolescents: a histological evaluation in beagle dogs

Small osseointegrated implants inserted in the palate provide a reliable anchorage control during orthodontic treatment. When these implants are inserted in the median palatal suture in adolescents, there might be interference with normal transverse development of the maxilla. The aim of this study was to determine histometrically the influence of implants inserted in the median palatal suture in adolescent beagle dogs on transverse maxillary development and to determine the amount of osseointegration of unloaded palatal implants in the median palatal suture in adolescent beagle dogs.

Two palatal implants were inserted in the median palatal suture in four of five adolescent beagle dogs. The experimental period took 25 weeks, and the dogs were subjected to a scheme of sequential point labelling with vital stains every 6 weeks. Insertion sites were examined microscopically and histometric analysis was performed.

Both anterior width and posterior width were wider in the control dog as compared with the average in the test dogs, 3.7% and 9.5%, respectively. After loss of a palatal implant, immediate repair of the bone in the suture area could be observed. In the posterior region, the repaired suture looked more like a suture in the infantile stage in humans, instead of having a sinusoidal course, as was observed in the control dog and in adolescent humans. The amount of osseointegration varied from 43% to 64.3%.

The results of this study support the idea that in adolescents, palatal implants should not be inserted in the median palatal suture because of possible growth impairment (transverse maxillary development). The amount of osseointegration of unloaded palatal implants in the median palatal suture in adolescent dogs is less as compared with dental implants in dogs and loaded palatal implants in adult humans.