Tsujino Keiichiro, Yonezu Takuro, Shintani Seikou
Division of Pediatric Dentistry, Department of Clinical Oral Science, Tokyo Dental College, Tokyo, Japan.
Pediatr Dent. 2013 Mar-Apr;35(2):E64-7.
The fusion of primary teeth may be associated with the absence of 1 of the 2 permanent successors. Moreover, even if both successors erupt, developmental disturbances such as microdontia or delayed tooth formation may occur. The purpose of this study was to elucidate the effects of different combinations of fused primary teeth on the eruption of permanent successors.
One hundred ninety-seven children with 247 fused primary teeth were examined. Combinations of primary teeth involved in the fusion were identified, and the effects of these different combinations on the presence, morphology, and eruption of the permanent successors were determined.
Three types of fusion in the primary teeth were identified: (1) between the maxillary central and lateral incisors (UCI/LI); (2) between the mandibular central and lateral incisors (LCI/LI); and (3) between the mandibular lateral incisor and canine (LLI/C). The results revealed an absence of the successional lateral incisor in 65% of UCI/LI cases and 74% of LLI/C cases, whereas only 16% of LCI/LI cases resulted in a missing successor.
Fused primary teeth are highly correlated with the absence of permanent teeth, and the prevalence depends on the combination of fused primary teeth.
乳牙融合可能与两颗恒牙胚中一颗缺失有关。此外，即使两颗恒牙胚都萌出，也可能出现诸如过小牙或牙齿发育延迟等发育障碍。本研究的目的是阐明不同组合的融合乳牙对恒牙胚萌出的影响。
对197名患有247颗融合乳牙的儿童进行检查。确定参与融合的乳牙组合，并确定这些不同组合对恒牙胚的存在、形态和萌出的影响。
确定了乳牙的三种融合类型：（1）上颌中切牙与侧切牙之间（UCI/LI）；（2）下颌中切牙与侧切牙之间（LCI/LI）；（3）下颌侧切牙与尖牙之间（LLI/C）。结果显示，65%的UCI/LI病例和74%的LLI/C病例中恒牙侧切牙缺失，而只有16%的LCI/LI病例导致恒牙胚缺失。
融合乳牙与恒牙缺失高度相关，其发生率取决于融合乳牙的组合。
