Korean J Orthod.  2018 May;48(3):189-199. 10.4041/kjod.2018.48.3.189.

Cone-beam computed tomography-based diagnosis and treatment simulation for a patient with a protrusive profile and a gummy smile

• Uesugi S
• Imamura T
• Kokai S
• Ono T

• KMID: 2418330
• DOI: http://doi.org/10.4041/kjod.2018.48.3.189

Abstract

For patients with bimaxillary protrusion, significant retraction and intrusion of the anterior teeth are sometimes essential to improve the facial profile. However, severe root resorption of the maxillary incisors occasionally occurs after treatment because of various factors. For instance, it has been reported that approximation or invasion of the incisive canal by the anterior tooth roots during retraction may cause apical root damage. Thus, determination of the position of the maxillary incisors is key for orthodontic diagnosis and treatment planning in such cases. Cone-beam computed tomography (CBCT) may be useful for simulating the post-treatment position of the maxillary incisors and surrounding structures in order to ensure safe teeth movement. Here, we present a case of Class II malocclusion with bimaxillary protrusion, wherein apical root damage due to treatment was minimized by pretreatment evaluation of the anatomical structures and simulation of the maxillary central incisor movement using CBCT. Considerable retraction and intrusion of the maxillary incisors, which resulted in a significant improvement in the facial profile and smile, were achieved without severe root resorption. Our findings suggest that CBCT-based diagnosis and treatment simulation may facilitate safe and dynamic orthodontic tooth movement, particularly in patients requiring maximum anterior tooth retraction.

Keyword

Cone-beam computed tomography; Digital simulation; Orthodontic mini-implant; Bimaxillary protrusion

MeSH Terms

Cone-Beam Computed Tomography
Diagnosis*
Humans
Incisor
Malocclusion
Root Resorption
Tooth
Tooth Movement
Tooth Root

Reference

1. Leonardi R, Annunziata A, Licciardello V, Barbato E. Soft tissue changes following the extraction of premolars in nongrowing patients with bimaxillary protrusion. A systematic review. Angle Orthod. 2010; 80:211–216.

2. Ayaz M, Kharbanda OP. Successful treatment of Class II malocclusion with bidental protrusion using standard edgewise prescription. Contemp Clin Dent. 2016; 7:75–78.

3. Parker RJ, Harris EF. Directions of orthodontic tooth movements associated with external apical root resorption of the maxillary central incisor. Am J Orthod Dentofacial Orthop. 1998; 114:677–683.

4. Han G, Huang S, Von den, Zeng X, Kuijpers-Jagtman AM. Root resorption after orthodontic intrusion and extrusion: an intraindividual study. Angle Orthod. 2005; 75:912–918.

5. Liou EJ, Chang PM. Apical root resorption in orthodontic patients with en-masse maxillary anterior retraction and intrusion with miniscrews. Am J Orthod Dentofacial Orthop. 2010; 137:207–212.

6. Weltman B, Vig KW, Fields HW, Shanker S, Kaizar EE. Root resorption associated with orthodontic tooth movement: a systematic review. Am J Orthod Dentofacial Orthop. 2010; 137:462–476.

7. Nakano Y, Yamaguchi M, Fujita S, Asano M, Saito K, Kasai K. Expressions of RANKL/RANK and M-CSF/c-fms in root resorption lacunae in rat molar by heavy orthodontic force. Eur J Orthod. 2011; 33:335–343.

8. Martins DR, Tibola D, Janson G, Maria FR. Effects of intrusion combined with anterior retraction on apical root resorption. Eur J Orthod. 2012; 34:170–175.

9. Zawawi KH, Malki GA. Radiographic comparison of apical root resorption after orthodontic treatment between bidimensional and Roth straight-wire techniques. J Orthod Sci. 2014; 3:106–110.

10. Roscoe MG, Meira JB, Cattaneo PM. Association of orthodontic force system and root resorption: a systematic review. Am J Orthod Dentofacial Orthop. 2015; 147:610–626.

11. Chung CJ, Choi YJ, Kim KH. Approximation and contact of the maxillary central incisor roots with the incisive canal after maximum retraction with temporary anchorage devices: Report of 2 patients. Am J Orthod Dentofacial Orthop. 2015; 148:493–502.

12. Song WC, Jo DI, Lee JY, Kim JN, Hur MS, Hu KS, et al. Microanatomy of the incisive canal using threedimensional reconstruction of microCT images: an ex vivo study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009; 108:583–590.

13. Liang X, Jacobs R, Martens W, Hu Y, Adriaensens P, Quirynen M, et al. Macro- and micro-anatomical, histological and computed tomography scan characterization of the nasopalatine canal. J Clin Periodontol. 2009; 36:598–603.

14. Matsumura T, Ishida Y, Kawabe A, Ono T. Quantitative analysis of the relationship between maxillary incisors and the incisive canal by cone-beam computed tomography in an adult Japanese population. Prog Orthod. 2017; 18:24.

15. Upadhyay M, Yadav S, Nagaraj K, Patil S. Treatment effects of mini-implants for en-masse retraction of anterior teeth in bialveolar dental protrusion patients: a randomized controlled trial. Am J Orthod Dentofacial Orthop. 2008; 134:18–29.

16. Lee KJ, Park YC, Hwang CJ, Kim YJ, Choi TH, Yoo HM, et al. Displacement pattern of the maxillary arch depending on miniscrew position in sliding mechanics. Am J Orthod Dentofacial Orthop. 2011; 140:224–232.