Implants for upper incisor replacement in growing individuals: a histomorphometric study in adolescent beagle dogs

Objectives: Congenital partial anodontia or traumatic tooth loss might compromise facial esthetics in children or adolescents. The viability of implant use in these patients is questioned since dental and skeletal growth are still present. The aim of the present study was to evaluate histomorphometrically the influence of implant placement in the upper front region in growing individuals on marginal bone level around the implant and the neighbouring teeth and on the alveolar growth in this region. Materials and methods: Four out of 5 adolescent beagle dogs received a dental implant immediately after extraction of tooth 1.1. The implants were not provided with a crown. All animals were subjected to a scheme of sequential point labelling with vital stains every 6 weeks. After a period of 25 weeks, dogs were sacrificed and specimens prepared for histological evaluation. Marginal bone level of the implant and lateral incisor were compared between the test side and the control side, and between test dogs and control dog. The amount of alveolar growth was evaluated by fluorescence microscopy. Results: Marginal bone loss of 3.9mm was observed around the implant and of 2.0mm on the implant side of the neighbouring tooth. The 2.0mm difference in marginal bone level between the tooth neighbouring the implant and the control tooth on the other side, can be attributed to a bone loss caused by the insertion of the implant (1.5mm) and arrest of alveolar growth (0.5mm). Conclusion: Both arrest in alveolar growth and bone loss due to implant insertion in the upper front region in adolescent beagle dogs, contribute to a total decrease of marginal bone level of 2.0mm as compared to a situation without implant.