Molar root-incisor malformation: considerations of diverse developmental and etiologic factors

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• 作者：John Timothy Wright ; DDS ; MS^a ; Alice Curran ; DMD ; MS^b ; Kyoung-Jin Kim ; DDS ; MS^c ; Yeon-Mi Yang ; DDS ; PhD^d ; Soon-Hyeun Nam ; DDS ; PhD^e ; Teo Jeon Shin ; MD ; PhD^c ; Hong-Keun Hyun ; DDS ; PhD^c ; Young-Jae Kim ; DDS ; PhD^c ; Sang-Hoon Lee ; DDS ; PhD^c ; Jung-Wook Kim ; DDS ; PhD^c ; ^f ; ^{pedoman@snu.ac.kr" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：121
• 期：2
• 页码：164-172
• 全文大小：1020 K

文摘

The objective of this study was to evaluate the variation in the condition referred to as molar root-incisor malformation (MRIM) and elucidate the distribution of affected teeth. This study further aimed to identify associated environmental stressors.

Study Design

Individuals were identified through retrospective review of dental radiographs and through referral to the investigators. Histologic evaluation included examination of mineralized and decalcified sections of affected first permanent molar teeth.

Results

Thirty cases of MRIM were identified, with all having affected first permanent molars with dysplastic root formation. The primary second molars were affected in 57% of the cases, with permanent anterior teeth being involved in 40% of the cases. A variety of medical conditions were associated with MRIM, the most common being neurologic. Several affected individuals reported no significant past medical history or environmental stressors.

Conclusions

The etiology of MRIM remains unclear, and this unique developmental defect of the first permanent molar roots appears to occur in populations throughout the world. Clinicians identifying the MRIM phenotype should carefully evaluate the permanent incisors for associated developmental defects that could result in pulpal necrosis.