Analysis of Factors Associated with Orthodontic Microscrew Failure

Abstract

The objective of this study was to examine whether factors such as insertion site, patient's facial pattern, microscrew features, type of tooth movement desired, level of experience handling orthodontic microscrews and operator expertise were associated with failure of microscrews. After the approval of an ethics committee, 166 patients of one practice signed an informed consent and received 293 microscrews randomly distributed by 3 operators with different levels of practical experience and expertise in handling microscrews. The microscrews were observed in a period of 365 days or as long as orthodontic forces had to be applied and independent variables were recorded. Analysis by the chi-square test did not produce enough evidence as to allow the assertion that there was an association between the variable "failure" and the variables "maxilla" (p=0.4775), "face" (p=0.1081), "facial pattern" (p=0.7522), "microscrew length" (p=0.9113), "desired movement" (p=0.0584), and "operator" (p=0.5785). The variable "insertion side" was significantly associated with "failure" (p=0.0022). In a 365-day survival analysis, the Log Rank test yielded a p-value of 0.00178 for the curve of variable "insertion side," and showed no significant differences for other variables. With a total success rate of 87.38%, the only variable found to be significant was "insertion side" (p=0.0022), with 3.088 more likelihood of a microscrew failing if placed on the left side than on the right side. The procedure of inserting microscrews involved a rapid learning curve for an inexperienced operator, which justifies their placement by orthodontists.

Risk factors for orthodontic mini-implants in skeletal anchorage biological stability: a systematic literature review and meta-analysis

“…In most of the studies mean patient age was around 25 years, samples generally consisting of predominantly young adults. Of the 26 articles, 7 were prospective studies [15][16][17][18][19][20][21] and 19 retrospective [11][12][13][14][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] . Follow-up periods ranged from approximately 18 months to 2 years.…”

“…www.nature.com/scientificreports www.nature.com/scientificreports/ between mini-implant failure and age. Some studies found no association between age and failure 14,15,32 , while others found that the patient's age could influence mini-implant failure because younger patients present finer cortical bone and lower bone density 19,[30][31][32][33][34] . (Fig.…”

Miniscrews and Mini-Implants Success Rates in Orthodontic Treatments: A Systematic Review and Meta-Analysis of Several Clinical Parameters

“…An important accent was focused on the site of surgery. As showed in Figure 2, a larger number of implants were placed in the maxilla rather than in the lower jaw, thus increasing the success rate in the maxilla in all but ten studies [6,[9][10][11][12][13][14][15][16][17].…”

Factors Associated with the Success of Orthodontic Miniscrews

“…Several studies have evaluated factors responsible for the failure of miniscrews. 13,14 Failure of miniscrews might be due to inflammation resulting from a poor bone-screw contact; 10 however, hostrelated factors such as age, gender, and cortical bone quality and thickness, and miniscrew-related factors such as diameter and length are considered important factor for the primary stability of miniscrews. [15][16][17] One of the techniques used to evaluate the primary stability of miniscrews is to measure insertion torque at the time of screw placement.…”