Cittadella Hospital, Cittadella, Italy.
Eur J Paediatr Dent. 2012 Sep;13(3):236-8.
Tooth eruption is defined as the movement of a tooth from its site of development within the alveolar process to its functional position in the oral cavity [Massler et al., 1941]. The process of tooth eruption can be divided into different phases: pre-eruptive bone stage, alveolar bone stage, mucosal stage, preocclusal stage, occlusal stage and maturation stage [Andreasen et al., 1997]. Any disturbance in these phases can lead to eruptive anomalies. The incidence of unerupted teeth is usually higher among permanent teeth than among deciduous ones [Walker et al., 2004; Otsuka et al., 2001; Amir et al., 1982; Broadway, 1976; Pinborg et al., 1970]. Of the primary teeth reported as unerupted, second primary molars are the teeth most frequently involved [Walker et al., 2004; Otsuka et al., 2001; Bianchi et al., 1991; Ranta et al., 1988; Tsukamoto et al., 1986; Amir et al., 1982], followed by primary central incisors [Otsuka et al., 2001].
This paper presents a case of inversion of the intraosseous position of a second unerupted deciduous molar and the succedaneous second premolar.
牙齿萌出是指牙齿从牙槽骨内的发育部位移动到口腔内的功能位置[Massler 等人，1941]。牙齿萌出的过程可分为不同阶段：萌出前牙槽骨阶段、牙槽骨阶段、黏膜阶段、萌出前阶段、咬合阶段和成熟阶段[Andreasen 等人，1997]。这些阶段中的任何干扰都可能导致萌出异常。未萌出的恒牙发生率通常高于乳牙[Walker 等人，2004；Otsuka 等人，2001；Amir 等人，1982；Broadway，1976；Pinborg 等人，1970]。在报告的未萌出乳牙中，第二乳磨牙是最常涉及的牙齿[Walker 等人，2004；Otsuka 等人，2001；Bianchi 等人，1991；Ranta 等人，1988；Tsukamoto 等人，1986；Amir 等人，1982]，其次是乳中切牙[Otsuka 等人，2001]。
本文报告了一例第二颗未萌出的乳磨牙和继生第二前磨牙的骨内位置倒置的病例。
