Un-Bong Baik1, Yoon-Ah Kook2, Mohamed Bayome3,4, Je-Uk Park5, Jae Hyun Park6,7. 1. a Private Practice, Seoul, Korea. 2. b Professor, Department of Orthodontics, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. 3. c Research Assistant Professor, Department of Orthodontics, College of Medicine, The Catholic University of Korea, Seoul, Korea. 4. d Visiting Professor, Department of Postgraduate Studies, Universidad Autonóma del Paraguay, Asunción, Paraguay. 5. e Professor, Department of Oral and Maxillofacial Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. 6. f Professor and Chair, Postgraduate Orthodontic Program, Arizona School of Dentistry & Oral Health, A.T. Still University, Mesa, Ariz. 7. g Adjunct Professor, Graduate School of Dentistry, Kyung Hee University, Seoul, Korea.
Abstract
OBJECTIVE: To investigate (1) whether vertical eruption of impacted third molars improves after mesialization of second molars and (2) what factors affect the vertical eruption of impacted third molars when space caused by missing molars is successfully closed by mesialization of the second molar using miniscrews. MATERIALS AND METHODS: The treatment group (Group 1) included 52 patients who had (1) missing mandibular first molars (ML-6) or missing deciduous mandibular second molars (ML-E), (2) initially impacted mandibular third molars, and (3) successful space closure of the edentulous area with orthodontics. Panoramic radiographs at start of treatment (T1) and at time of space closure (T2) were collected. The control group (Group 2) included 46 nonedentulous patients with impacted mandibular third molars without molar protraction treatment. Panoramic radiographs with similar T1/T2 treatment times were selected. Nine measurements were obtained regarding horizontal available space, vertical eruption, and third molar angulation. RESULTS: Third molars erupted vertically an average of 2.54 mm in Group 1 compared with 0.41 mm in Group 2. Age, gender, Nolla stage, and angle of the third molars did not show significant correlations with the vertical change of the impacted third molars, whereas the depth of third molar impaction and available space showed significant correlations. CONCLUSIONS: Impacted mandibular third molars vertically erupt as a result of uprighting with mesialization of the second molar, and vertical eruption is affected by the initial vertical location of impacted third molars and available space.
OBJECTIVE: To investigate (1) whether vertical eruption of impacted third molars improves after mesialization of second molars and (2) what factors affect the vertical eruption of impacted third molars when space caused by missing molars is successfully closed by mesialization of the second molar using miniscrews. MATERIALS AND METHODS: The treatment group (Group 1) included 52 patients who had (1) missing mandibular first molars (ML-6) or missing deciduous mandibular second molars (ML-E), (2) initially impacted mandibular third molars, and (3) successful space closure of the edentulous area with orthodontics. Panoramic radiographs at start of treatment (T1) and at time of space closure (T2) were collected. The control group (Group 2) included 46 nonedentulous patients with impacted mandibular third molars without molar protraction treatment. Panoramic radiographs with similar T1/T2 treatment times were selected. Nine measurements were obtained regarding horizontal available space, vertical eruption, and third molar angulation. RESULTS: Third molars erupted vertically an average of 2.54 mm in Group 1 compared with 0.41 mm in Group 2. Age, gender, Nolla stage, and angle of the third molars did not show significant correlations with the vertical change of the impacted third molars, whereas the depth of third molar impaction and available space showed significant correlations. CONCLUSIONS: Impacted mandibular third molars vertically erupt as a result of uprighting with mesialization of the second molar, and vertical eruption is affected by the initial vertical location of impacted third molars and available space.
Entities:
Keywords:
Impacted mandibular third molars; Mesialization; Miniscrews; Second molars; Vertical eruption patterns