A prospective study of the risk factors associated with failure of mini-implants used for orthodontic anchorage.
OBJECTIVE
The aim of this prospective clinical study was to assess the risk factors associated with failure of mini-implants used for orthodontic anchorage.


METHODS
A total of 140 mini-implants in 44 patients, including 48 miniplates and 92 freestanding miniscrews, were examined in the study. A variety of orthodontic loads were applied. The majority of implants were placed in the posterior maxilla (104/140), and the next most common location was the posterior mandible (34/140).


RESULTS
A cumulative survival rate of 89% (125/140) was found by Kaplan-Meier analysis. There was no significant difference in the survival rate between miniplates and freestanding miniscrews, but miniplates were used in more hazardous situations. The Cox proportional-hazards regression model identified anatomic location and peri-implant soft tissue character as 2 independent prognostic indicators. The estimated relative risk of implant failure in the posterior mandible was 1.101 (95% confidence interval, 0.942 to 1.301; P = .046). The risk ratio of failure for implants surrounded by nonkeratinized mucosa was 1.117 (95% confidence interval, 0.899 to 1.405; P = .026).


CONCLUSIONS
The results confirmed the effectiveness of orthodontic mini-implants, but in certain situations adjustment of the treatment plan or modifications in the technique of implant placement may lead to improved success rates.
Department of Dentistry, Sun-Yat-San Cancer Center, Taipei, Taiwan.
Shih-Jung
SJ
Cheng
I-Yun
IY
Tseng
Jang-Jaer
JJ
Lee
Sang-Heng
SH
Kok
D000293:Adolescent; D000328:Adult; D001860:Bone Plates; D001863:Bone Screws; D003758:Dental Implantation, Endosseous / Q000009:adverse effects*; D015921:Dental Implants / Q000009:adverse effects*; D003799:Dental Stress Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D010518:Periodontitis / Q000209:etiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013530:Surgical Wound Infection / Q000209:etiology; D016019:Survival Analysis; D014087:Tooth Movement Techniques / Q000295:instrumentation*
D015921:Dental Implants