Miniscrews in orthodontic treatment: Review and analysis of published clinical trials
ABSTRACT A systematic review of effects related to patient, screw, surgery, and loading on the stability of miniscrews was conducted.
Reports of clinical trials published before September 2007 with at least 30 miniscrews were reviewed. Parameters examined were patient sex and age, location and method of screw placement, screw length and diameter, time, and amount of loading.
Fourteen clinical trials included 452 patients and 1519 screws. The mean overall success rate was 83.8% + or - 7.4%. Patient sex showed no significant differences. In terms of age, 1 of 5 studies with patients over 30 years of age showed a significant difference (P <0.05). Screw diameters of 1 to 1.1 mm yielded significantly lower success rates than those of 1.5 to 2.3 mm. One study reported significantly lower success rates for 6-mm vs 8-mm long miniscrews (72% vs 90%). Screw placement with or without a surgical flap showed contradictory results between studies. Three studies showed significantly higher success rates for maxillary than for mandibular screws. Loading and healing period were not significant in the miniscrews' success rates.
All 14 articles described success rates sufficient for orthodontic treatment. Placement protocols varied markedly. Screws under 8 mm in length and 1.2 mm in diameter should be avoided. Immediate or early loading up to 200 cN was adequate and showed no significant influence on screw stability.
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ABSTRACT: Summary AIM : The purpose of this study was to assess the difference of removal torque values (RTV) and the bone-to-implant contact (BIC) between the sand-blasted, large grit, and acid-etched (SLA) surface-treated and the machined surface (MA) miniscrews. Miniscrews used in this study were 6mm long with a diameter of 1.5mm. A total of 23 SLA miniscrews and 24 MA miniscrews were placed into the distal femoral condyle of 24 New Zealand rabbits. Removal torque test and the BIC was histologically evaluated at 0 and 8 weeks. There was no statistical difference between the RTV in the MA group versus the SLA group at both 0 and 8 weeks. Comparing 0-8 weeks, there was no significant difference in RTV of the SLA group (P = 0.48), however the change in the MA group was statistically significant (P = 0.006). Histological observation showed a significant decrease in BIC comparing 0 and 8 weeks for the MA group. The BIC ratio at 8 weeks was statistically significantly higher in the SLA group compared to the MA group. SLA surface preparation does not increase the RTV of miniscrews. Further investigations under loading and a large sample size are required. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: email@example.com.The European Journal of Orthodontics 01/2015; DOI:10.1093/ejo/cju077 · 1.39 Impact Factor
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ABSTRACT: The purpose of this survey was to determine how commonly, and in what clinical situations, German-based orthodontists use skeletal anchorage devices in daily clinical practice. In early 2013, a set of questionnaires on the subject of skeletal anchorage devices was mailed to 2459 members of the German Orthodontic Society (Deutsche Gesellschaft für Kieferorthopädie, DGKFO). The questions dealt separately with miniscrews (MSCs) and osseointegrated palatal implants (OPIs). The addressees were asked whether or not, as well as how frequently and in what clinical situations, they used these MSCs and/or OPIs, what their experience was, and to elaborate on their reasons for using or not using these devices. The rate of returned questionnaires was 48 %. To correctly interpret our data, it should be kept in mind that an unknown number of respondents did not distinguish between OPIs and palatally inserted MSCs. Overall, 62 % indicated that they did use MSCs and/or OPIs, although most of them (> 50 %) infrequently (≤ 2 new patients/3 months). Only ≤ 2 % were frequent users (> 2 new patients/week). While most users (> 70 %) indicated that their experience was mostly good, only ≤ 50 % considered the devices easy and trouble-free to use in daily clinical practice. The median percentage of insertion procedures conducted by the respondents themselves was 2 % for MSCs and 0 % for OPIs. Many of the non-users indicated that their treatment concept did not include suitable clinical indications (≥ 50 %), expressed skepticism about the success rates (56 % of MSC and 21 % of OPI non-users), or thought that the insertion procedures involved were too complex or time-consuming (33 % of MSC and 56 % of OPI non-users). A total of 62 % of German-based orthodontists participating in this survey indicated using skeletal anchorage devices, although most of them infrequently. Major reasons for non-use were lack of clinical indications, skepticism about the success rate of MSCs, and overly complex or time-consuming procedures of surgical OPI insertion.Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie 03/2015; 76(2). DOI:10.1007/s00056-014-0275-z · 0.82 Impact Factor
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ABSTRACT: A growing number of studies have reported that mini-implants do not remain in exactly the same position during treatment, although they remain stable. The aim of this review was to collect data regarding primary displacement immediately straight after loading and secondary displacement over time. A systematic review was performed to investigate primary and secondary displacement. The amount and type of displacement were recorded. A total of 27 studies were included. Sixteen in vitro studies or studies using finite element analysis addressed primary displacement, and nine clinical studies and two animal studies addressed secondary displacement. Significant primary displacement was detected (6.4-24.4 µm) for relevant orthodontic forces (0.5-2.5 N). The mean secondary displacement ranged from 0 to 2.7 mm for entire mini-implants. The maximum values for each clinical study ranged from 1.0 to 4.1 mm for the head, 1.0 to 1.5 for the body and 1.0 to 1.92 mm for the tail part. The most frequent type of movement was controlled tipping or bodily movement. Primary displacement did not reach a clinically significant level. However, clinicians can expect relevant secondary displacement in the direction of force. Consequently, decentralized insertion within the inter-radicular space, away from force direction, might be favourable. More evidence is needed to provide quantitative recommendations.International Journal of Oral Science (2013) 5, doi:10.1038/ijos.2013.92; published online 13 December 2013.International Journal of Oral Science 12/2013; 6(1). DOI:10.1038/ijos.2013.92 · 2.03 Impact Factor