Effects on Alveolar Bone During Tooth Movement in a GD3 Synthase Gene Deficient Mice

Abstract

Orthodontic treatment involves tooth movement through alveolar bone metabolism caused by orthodontic force. Ganglioside GD3 glycolipid is expressed in the brain, cranial nerves, and osteoclasts. Femur bone resorption was suppressed in aged GD3 synthase gene deficient (GD3S KO) mice. This study investigated the effects on alveolar bone metabolism in GD3S KO mice. Closed coiled springs were fitted into the alveolar region of maxillary anterior teeth and left first molar (M1) of GD3S KO (n=6) and wild-type mice (Wild: n=6) to apply orthodontic force and induce tooth movement. After 21 days, they were euthanized; micro-computed tomography measured the tooth-movement distance and remaining alveolar bone volume (BV/TV) of the interradicular septum of M1. Osteoblasts and osteoclasts were measured using hematoxylin-eosin and tartrate-resistant acid phosphatase staining, respectively. Sympathetic and sensory nerve activities were evaluated using immunostaining. GD3S KO mice showed a significant decrease in tooth-movement distance and increased BV/TV of interradicular septum compared with Wild. Osteoblast count was insignificant; however, significantly lower osteoclast count and sympathetic and sensory nerve activities were observed in GD3S KO mice than Wild. GD3S KO mice had decreased tooth movement and bone mass maintenance with reduced sympathetic nerve activity and nerve regeneration in the periodontal ligament.