Prevalence and treatment of mandibular first molar eruption disturbances

Son,  Woo-Sung; Song,  Hyo-Kyung; Kim,  Seong Sik

J Korean Dent Assoc > Volume 55(5); 2017 > Article

The Journal of The Korean Dental Association 2017;55(5):328-338.
Published online May 31, 2017.

하악 제 1대구치 맹출 장애의 빈도와 치료

손우성¹, 송효경², 김성식³

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Prevalence and treatment of mandibular first molar eruption disturbances

Woo-Sung Son¹, Hyo-Kyung Song², Seong Sik Kim³

¹Department of Orthodontics, School of Dentistry, Pusan National University
²Department of Orthodontics, School of Dentistry, Pusan National University
³Department of Orthodontics, School of Dentistry, Pusan National University

Abstract

Introduction: The aim of the current study was to describe the prevalence and treatment of mandibular first molar eruption disturbances. Methods: A total of 38 mandibular first molars(M1mn) from 36 patients(17 males and 19 females; aged 9 years 2 months?35 years 10 months) were identified from the 13,391 patients that received orthodontic treatment from 1983?2012. The subjects were classified into 3 categories based on panoramic radiographic examination: impaction due to ectopic position of the tooth germ relative to the contra-side same tooth(Group 1), impaction due to obstruction of the eruption path with cyst or calcium mass (Group 2), and primary and secondary retention due to defects in the follicle or periodontal ligament(PDL; Group 3). The treatment outcomes were evaluated into four categories: no treatment(A), orthodontic traction(B), autotransplantation(C), and extraction due to orthodontic traction failure(D). Results: The prevalence rate of M1mn eruption disturbances in this sample was 0.27%. In Groups 1 and 2, most of the impacted M1mn were erupted successfully by orthodontic traction. In Group 3, most of the retained M1mn were failed to erupt and recommended for extraction. Conclusions: Treatment prognosis was favorable on Group 1 & 2 than Group 3. After removing an element of the cause in case of Group 1 & 2, orthodontic traction or periodic observation will be recommended.

Key Words: Lower first mandibular impaction;primary eruption failure;secondary eruption failure;ankylosis;