Brief Article
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World J Stomatol. Aug 20, 2013; 2(3): 56-61
Published online Aug 20, 2013. doi: 10.5321/wjs.v2.i3.56
Evaluation of factors affecting the success rate of orthodontic mini-implants by survival analysis
Un-Bong Baik, Mohamed Bayome, Kwang-Heung Han, Jae Hyun Park, Min-Ho Jung, Yoon-Ah Kook
Un-Bong Baik, Smile with Orthodontic Clinic, Seoul 142-100, South Korea
Mohamed Bayome, Department of Orthodontics, The Catholic University of Korea, Seoul 137-701, South Korea
Kwang-Heung Han, Seoul H Dental Clinic, Seoul 150-037, South Korea
Jae Hyun Park, Postgraduate Orthodontic Program, Arizona School of Dentistry and Oral Health, A.T. Still University, Mesa, AZ and Graduate School of Dentistry, Kyung Hee University, Seoul 130-701, South Korea
Min-Ho Jung, Private practice and Department of Orthodontics, School of Dentistry, Seoul National University, Seoul 151-742, South Korea
Yoon-Ah Kook, Department of Orthodontics, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 137-701, South Korea
Author contributions: All the authors contributed equally to this manuscript.
Correspondence to: Dr. Yoon-Ah Kook, Department of Orthodontics, Seoul St. Mary’s Hospital, The Catholic University of Korea, 505 Banpo-Dong, Seocho-Gu, Seoul 137-701, South Korea. kook190036@yahoo.com
Telephone: +82-2-22581776 Fax: +82-2-5372374
Received: December 17, 2012
Revised: February 17, 2013
Accepted: April 10, 2013
Published online: August 20, 2013
Processing time: 173 Days and 22.3 Hours
Abstract

AIM: To investigate the success rate of mini-implants and its characteristics and risk factors by survival analyses.

METHODS: Three hundred and ninety-four mini-implants of the same type were placed by a single clinician. Age, gender, treatment duration, time of failure, side and jaw of implantation and the soft tissue at placement site were recorded. Odds ratio, survival curves, and Cox proportional hazard model were applied to evaluate the factors influencing the mini-implants’ success rate.

RESULTS: The cumulative success rate was 88.1%. The maxilla had a significantly higher success rate than that of the mandible (91.7% vs 83.7%, respectively, P = 0.019). Placement of mini-implants in the attached gingiva (AG) showed a higher success rate than that of the mucogingival junction (MGJ) and mucous membrane (MM) (AG, 94.3%; MGJ, 85.8%; MM, 79.4%; P < 0.001). Significant association was found between the jaw and the gingival tissue type (P < 0.001). There were no significant differences between maxilla and mandible when compared within each placement site.

CONCLUSION: The gingival tissue type had the most significant effect on the success rate of the mini-implant with higher success rate in the attached gingiva.

Keywords: Mini-implant, Success rate, Survival analysis, Gingival tissue, Treatment planning

Core tip: Anchorage reinforcement is a critical factor for successful orthodontic treatment outcome. Mini-implants are applied to achieve various dental movements such as anterior retraction, molar protraction and distalization, intrusion, extrusion, and correction of midline and occlusal canting. The gingival tissue type had the most significant effect on the success rate of the mini-implant with higher success rate in the attached gingiva.