Abstract: Objective: To investigate the histological morphology of mandibular first molar tooth germ and analyse dental phenotype in caveolin-1 gene knockout (KO) mice. Methods: After genotype identification with polymerase chain reaction (PCR), mandibular first molar germs and teeth were collected from caveolin-1 gene knockout mice and wild-type (WT) homologous mice. The histological morphology of tooth germs and dental phenotype were studied by hematein eosin(HE)staining and micro computed tomography (Micro-CT),respectively. Results:At E14.5, the tooth germ of WT mouse was at the cap stage; however, the tooth germ of KO mouse was still at the bud stage, and no obvious stratification and primary enamel knot were found. With the tooth germ development, the enamel organ cells of KO mouse stratified into four layers at cap stage (E16.5). While, enamel organ of KO mouse had smaller volume and less invagination of cervical loop into epithelial mesenchymal. At E18.5, the cell polarities of both ameloblasts and odontoblasts were not obvious in KO tooth germ. And the odontoblasts were lack of typical high columnar shapes. The results of Micro-CT and 3D reconstruction showed that no significant difference was found between the two mice’s lower first molar anatomic shape. Conclusion: The deficiency of caveolin-1 gene led to temporal arrest for the bud-to-cap transition in developmental molar tooth germs without significant influence on the later developmental processes.

Key words: Caveolin-1, Tooth development, Micro-CT, Phenotypic observation