Efficacy of Infrazygomatic Crest Implants for Full-arch Distalization of Maxilla and Reduction of Gummy Smile in Class II Malocclusion
Amir Shaikh, Asna Fatima Jamdar, Shakeel Ahmed Galgali, Smita Patil, Inayat Patel
Gummy smile, Infrazygomatic crest implants, Intrusion, Maxillary arch distalization, Skeletal anchorage, Skeletal class II discrepancy
Citation Information :
Shaikh A, Jamdar AF, Galgali SA, Patil S, Patel I. Efficacy of Infrazygomatic Crest Implants for Full-arch Distalization of Maxilla and Reduction of Gummy Smile in Class II Malocclusion. J Contemp Dent Pract 2021; 22 (10):1135-1143.
Aim: The purpose of the study was to evaluate the efficacy of infrazygomatic (IZ) implants along with mini-implants for full-arch distalization of maxilla and reduction of gummy smile in patients with class II division I malocclusion.
Materials and methods: Ten orthodontic patients were taken from the department of orthodontics and dentofacial orthopedics. Each patient required distalization and intrusion of the complete maxillary arch as a part of the treatment plan. Patients were of class II malocclusion with gummy smile. Initial leveling and alignment were done by using 0.22″ slot Mclaughlin Bennett Trevisi (MBT) prescription. Fav Anchor infrazygomatic crest (IZC) implants of 2 mm of head diameter and 14 mm length were inserted between first and second molar and 2 mm above the mucogingival junction in the alveolar mucosa and in the anterior region, two titanium mini-implants of 1.4 mm head diameter and 6 mm length. The screws were loaded immediately with e-chain with a minimal force from mini-implants in the anterior region to crimpable hook placed between lateral and canine and continuing the same till the IZ implants. To measure the amount of distalization and reduction of gummy smile, pre- and postlateral cephalograms were taken and assessed. Pre- and postdistalization and intrusion readings of all patients were obtained and calculated statistically for quantifying the amount of distalization of maxillary arch and intrusion for reduction of gummy smile.
Results: The distalization of the maxillary arch achieved was 4.6 mm which is clinically and statistically significant. The anterior teeth in the study were intruded with a minimum of 3.8 mm which is clinically and statistically significant; the gingival smile line was reduced with a mean of 3.4 mm which is clinically and statistically significant. Overbite correction of 4 mm was done with the mean difference of 4 mm which is also statistically significant.
Conclusion: The IZ bone screws can be effectively used as an absolute anchorage to correct class II skeletal discrepancy with gummy smile devoid of premolar extraction with noninvasive procedure.
Clinical significance: The use of IZC implants along with anterior implants, a biomechanical approach is effective in achieving full-arch distalization of maxilla and intrusion as the force vectors allow that the line of action passes through the center of resistance (Cr) of the entire maxillary arch, facilitates the distalization and intrusion of the maxillary arch, establishes ideal occlusion, and improves the smile esthetics.
Melsen B. Mini-implants: where are we? J Clin Orthod 2005;39(9):539. PMID: 16244412.
Papadopolous MA. Non-compliance approaches for management of class II malocclusion. In: Current principles and techniques. Edinburg: Elsevier, Mosby; 2006.
Gainsforth BL, Higley LB. A study of orthodontic anchorage possibilities in basal bone. Am J Orthod Oral Surg 1945;31(8):406–417. DOI: 10.1016/0096-6347(45)90025-1.
Fayed MM, Pazera P, Katsaros C. Optimal sites for orthodontic mini-implant placement assessed by cone beam computed tomography. Angle Orthod 2010;80(5):939–951. DOI: 10.2319/121009-709.1.
Chen YJ, Kao CT, Huang TH. Evaluation of ten extra-alveolar temporary anchorage device insertion sites by cone beam volumetric computer tomography: a pilot study. J Dent Sci 2010;5(1):21–29. DOI: 10.1016/S1991-7902(10)60004-9.
Ghosh A. Infra-zygomatic crest and buccal shelf-orthodontic bone screws: a leap ahead of micro-implants–clinical perspectives. J Indian Orthod Soc 2018;52(4_suppl2):127–141. DOI: 10.4103/jios.jios_229_18.
Hsu E, Lin JSY, Yeh HY, et al. Comparison of the failure rate for infra-zygomatic bone screws placed in movable mucosa or attached gingiva. Int J Orthod Implantol 2017;47.
Lin JJJ, Roberts WE. Guided infra-zygomatic screws: reliable maxillary arch retraction. Int J Orthodont Implantol 2017;46.
Lee JY, Chae HS, Kim YH. Total arch distalization and control of transverse discrepancy with TADs. In: Temporary anchorage devices in clinical orthodontics. 2020. p. 213–221.
Lee KJ, Kim SJ. Advanced biomechanics for total arch movement and non-surgical treatment for hyperdivergent faces. Semin Orthod 2018;24(1):83–94. DOI: 10.1053/j.sodo.2018.01.008.
Mohamed MF. Treatment of gummy smile with maxillary anterior teeth intrusion using miniscrews.
Shetty SK, Mahesh Kumar Y, Vijayan LG, et al. Advanced methods of total arch distalization in orthodontics: a literature review. Int J Sci Res 2018;7:426. DOI: 10.21275/ART20196070.
Singh G, Gupta N, Goyal V, et al. En masse distalisation of maxillary arch using TADs (IZC); passive self-ligating appliance v/s clear aligner – a comparative cephalometric study. J Contemp Orthod 2019;3(3):11–17.
Wang CH, Wu JH, Lee KT, et al. Mechanical strength of orthodontic infrazygomatic mini-implants. Odontology 2011;99(1):98–100. DOI: 10.1007/s10266-010-0142-3.
Creekmore TD. The possibility of skeletal anchorage. J Clin Orthod 1983;17(4):266–269. PMID: 6574142.
Doruk C, Çankaya ÖS, Güvenç İS. Non-extraction treatment of skeletal class II adult patient with total maxillary arch distalization. Turkish J Orthod 2015;28(3):122–128. DOI: 10.5152/TurkJOrthod. 2016.15-00021R1.
Sugawara J, Daimaruya T, Umemori M, et al. Distal movement of mandibular molars in adult patients with the skeletal anchorage system. Am J Orthod Dentofacial Orthop 2004;125(2):130–138. DOI: 10.1016/j.ajodo.2003.02.003.
Sung EH, Kim SJ, Chun YS, et al. Distalization pattern of whole maxillary dentition according to force application points. Korean J Orthod 2015;45(1):20–28. DOI: 10.4041/kjod.2015.45.1.20.
Lin JC, Yeh C, Liou EJ, et al. Treatment of skeletal-origin gummy smiles with miniscrew anchorage. J Clin Orthod 2008;42(5):285. PMID: 18771123.
de Almeida MR. The biomechanics of extra-alveolar TADs in orthodontics. In: Temporary anchorage devices in clinical orthodontics. 2020. p. 445–454.
Yoshida N, Koga Y, Mimaki N, et al. In vivo determination of the centres of resistance of maxillary anterior teeth subjected to retraction forces. Eur J Orthod 2001;23(5):529–534. DOI: 10.1093/ejo/23.5.529.
Upadhyay M, Nagaraj K, Yadav S, et al. Mini-implants for en masse intrusion of maxillary anterior teeth in a severe Class II division 2 malocclusion. J Orthod 2008;35(2):79–89. DOI: 10.1179/146531207225022491.
Chung KR, Choo H, Kim SH, et al. Timely relocation of mini-implants for uninterrupted full-arch distalization. Am J Orthod Dentofacial Orthop 2010;138(6):839–849. DOI: 10.1016/j.ajodo.2009.02.035.
De Almeida MR, De Almeida RR, Nanda R. Biomechanics of extra-alveolar mini-implant use in the infrazygomatic crest area for asymmetrical correction of class II subdivision malocclusion. APOS Trends Orthod 2018;8(2):110–118. DOI: 10.4103/apos.apos_25_18.
Bechtold TE, Kim JW, Choi TH, et al. Distalization pattern of the maxillary arch depending on the number of orthodontic miniscrews. Angle Orthod 2013;83(2):266–273. DOI: 10.2319/032212-123.1.
Sanap S, Swami V, Patil A, et al. Evaluation of efficacy of various implants in maxillary arch distalization – a finite element analysis. Orthod J Nepal 2020;10(1):44–54. DOI: 10.3126/ojn.v10i1.31005.
Liou EJ, Chen PH, Wang YC, et al. A computed tomographic image study on the thickness of the infrazygomatic crest of the maxilla and its clinical implications for miniscrew insertion. Am J Orthod Dentofacial Orthop 2007;131(3):352–356. DOI: 10.1016/j.ajodo.2005.04.044.
Kim HJ, Yun HS, Park HD, et al. Soft-tissue and cortical-bone thickness at orthodontic implant sites. Am J Orthod Dentofacial Orthop 2006;130(2):177–182. DOI: 10.1016/j.ajodo.2004.12.024.
Kuroda S, Yamada K, Deguchi T, et al. Root proximity is a major factor for screw failure in orthodontic anchorage. Am J Orthod Dentofacial Orthop 2007;131(4):S68–S73. DOI: 10.1016/j.ajodo.2006.06.017.
Saxena R, Kumar PS, Upadhyay M, et al. A clinical evaluation of orthodontic mini-implants as intraoral anchorage for the intrusion of maxillary anterior teeth. World J Orthod 2010;11(4):346. PMID: 21491000.
Almeida MR. Biomechanics of extra-alveolar mini-implants. Dental Press J Orthod 2019;24(4):93–109. DOI: 10.1590/2177-6709.24.4.093-109.sar.