Tooth eruption is defined as the movement of the tooth from its site of development in alveolar bone to the occlusal plane in the oral cavity. The tooth eruption is a complex and tightly regulated process which is divided into five stages: pre-eruptive movements, intraosseous stage, mucosal penetration, preocclusal and postocclusal stages. Preeruptive movements occur during crown formation and are so small that they could only be observed by vital staining experiments. Active eruption movements occur when root formation begins and therefore it was believed that eruptive force comes from periodontal ligament.
Although tooth eruption mechanisms are still under debate, it was suggested that periodontal ligament
provides eruption force after the tooth has pierced gingiva but not during intraosseous stage. For active tooth eruption to begin eruption pathway by osteoclasts in alveolar bone must be formed. In succedeaneous dentition, this pathway follows the gubernacular canal above each tooth; i.e., bone resorption widens the canal to allow the crown to move through it and exit the alveolar bone.
Factors Influencing Tooth Eruption