Biomechanical considerations for uprighting impacted mandibular molars
2
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
This case report demonstrates two different uprighting mechanics separately applied to mesially tipped mandibular first and second molars. The biomechanical considerations for application of these mechanisms are also discussed. For repositioning of the first molar, which was severely tipped and deeply impacted, a novel cantilever mechanics was used. The molar tube was bonded in the buccolingual direction to facilitate insertion of a cantilever from the buccal side. By twisting the distal end of the cantilever, sufficient uprighting moment was generated. The mesial end of the cantilever was hooked over the miniscrew placed between the canine and first premolar, which could prevent exertion of an intrusive force to the anterior portion of the dentition as a side effect. For repositioning of the second molar, an uprighting mechanics using a compression force with two step bends incorporated into a nickel-titanium archwire was employed. This generated an uprighting moment as well as a distal force acting on the tipped second molar to regain the lost space for the first molar and bring it into its normal position. This epoch-making uprighting mechanics could also minimize the extrusion of the molar, thereby preventing occlusal interference by increasing interocclusal clearance between the inferiorly placed two step bends and the antagonist tooth. Consequently, the two step bends could help prevent occlusal interference. After 2 years and 11 months of active treatment, a desirable Class I occlusion was successfully achieved without permanent tooth extraction.
Abstract
This case report demonstrates two different uprighting mechanics separately applied to mesially tipped mandibular first and second molars. The biomechanical considerations for application of these mechanisms are also discussed. For repositioning of the first molar, which was severely tipped and deeply impacted, a novel cantilever mechanics was used. The molar tube was bonded in the buccolingual direction to facilitate insertion of a cantilever from the buccal side. By twisting the distal end of the cantilever, sufficient uprighting moment was generated. The mesial end of the cantilever was hooked over the miniscrew placed between the canine and first premolar, which could prevent exertion of an intrusive force to the anterior portion of the dentition as a side effect. For repositioning of the second molar, an uprighting mechanics using a compression force with two step bends incorporated into a nickel-titanium archwire was employed. This generated an uprighting moment as well as a distal force acting on the tipped second molar to regain the lost space for the first molar and bring it into its normal position. This epoch-making uprighting mechanics could also minimize the extrusion of the molar, thereby preventing occlusal interference by increasing interocclusal clearance between the inferiorly placed two step bends and the antagonist tooth. Consequently, the two step bends could help prevent occlusal interference. After 2 years and 11 months of active treatment, a desirable Class I occlusion was successfully achieved without permanent tooth extraction.
참고문헌 (28)
- Dachi SF, "A survey of 3,874 routine fullmonth radiographs. II. A study of impacted teeth", Oral Surg Oral Med Oral Pathol, 14, pp.1165~1169 (1961)
- Chu FC, "Prevalence of impacted teeth and associated pathologies--a radiographic study of the Hong Kong Chinese population", Hong Kong Med J, 9, pp.158~163 (2003)
- Keris EY, "Prevalence and characteristics of impacted permanent molars in a Turkish subpopulation", J Oral Maxillofac Radiol, 4, pp.45~49 (2016)
- Roberts WW 3rd, "A segmental approach to mandibular molar uprighting", Am J Orthod, 81, pp.177~184 (1982)
- Kuhlberg AJ, "Cantilever springs : force system and clinicalapplications", Semin Orthod, 7, pp.150~159 (2001)
- Lee KJ, "Uprighting mandibular second molars with direct miniscrew anchorage", J Clin Orthod, 41, pp.627~635 (2007)
- Shapira Y, "Uprighting mesially impacted mandibular permanent second molars", Angle Orthod, 68, pp.173~178 (1998)
- Majourau A, "Uprighting impacted second molars with segmented springs", Am J Orthod Dentofacial Orthop, 107, pp.235~238 (1995)
- Fu PS, "Management of unilaterally deep impacted first, second, and third mandibular molars", Angle Orthod, 82, pp.565~571 (2012)
- Resch D, "Clinical management of unilaterally impacted mandibular first and second molars", J Clin Orthod, 37, pp.162~164 (2003)
- Mehrotra R, "Management of unilaterally impacted permanent mandibular first, second and third molars", J Ind Orthod Soc, 48, pp.419~428 (2014)
- Lau CK, "Orthodontic uprighting of severely impacted mandibular second molars", Am J Orthod Dentofacial Orthop, 143, pp.116~124 (2013)
- Raveli TB, "Molar uprighting : a considerable and safe decision to avoid prosthetic treatment", Open Dent J, 31, pp.466~475 (2017)
- Fu PS, "Impacted mandibular second molars", Angle Orthod, 82, pp.670~675 (2012)
- Sawicka M, "Uprighting partially impacted permanent second molars", Angle Orthod, 77, pp.148~154 (2007)
- Magkavali-Trikka P, "Mandibular molar uprighting using orthodontic miniscrew implants : a systematic review", Prog Orthod, 19, pp.1~ (2018)
- Park HS, "A simple method of molar uprighting with micro-implant anchorage", J Clin Orthod, 36, pp.592~596 (2002)
- Giancotti A, "Miniscrew treatment of ectopic mandibular molars", J Clin Orthod, 37, pp.380~383 (2003)
- Giancotti A, "Treatment of ectopic mandibular second molar with titanium miniscrews", Am J Orthod Dentofacial Orthop, 126, pp.113~117 (2004)
- Barros SE, "Expanding torque possibilities : a skeletally anchored torqued cantilever for uprighting"kissing molars"", Am J Orthod Dentofacial Orthop, 153, pp.588~598 (2018)
- Mah SJ, "Uprighting mesially impacted mandibular molars with 2 miniscrews", Am J Orthod Dentofacial Orthop, 148, pp.849~861 (2015)
- Nienkemper M, "Uprighting mesially impacted lower third molars with skeletal anchorage", J Clin Orthod, 50, pp.420~426 (2016)
- Melo AC, "Lower molar uprighting with miniscrew anchorage : direct and indirect anchorage", Int J Orthod Milwaukee, 24, pp.9~14 (2013)
- Miyawaki S, "Factors associated with the stability of titanium screws placed in the posterior region for orthodontic anchorage", Am J Orthod Dentofacial Orthop, 124, pp.373~378 (2003)
- Cheng SJ, "A prospective study of the risk factors associated with failure of mini-implants used for orthodontic anchorage", Int J Oral Maxillofac Implants, 19, pp.100~106 (2004)
- Kravitz ND, "Risks and complications of orthodontic miniscrews", Am J Orthod Dentofacial Orthop, 131, pp.S43~51 (2007)
- Lai TT, "Factors affecting the clinical success of orthodontic anchorage : experience with 266temporary anchorage devices", J Dent Sci, 9, pp.49~55 (2014)
- Chang CH, "Ramus screws : the ultimate solution for lower impacted molars", Semin Orthod, 24, pp.135~154 (2018)