REVIEW ANALYSIS & EVALUATION

ARTICLE TITLE ANDBIBLIOGRAPHICINFORMATION

Systematic review of mini-implantdisplacement under orthodonticloading.

Nienkemper M, Handschel J, Drescher D.

Int J Oral Sci 2014;6:1–6.

REVIEWER

Mohammed Khalil Al-Dhubhani,BDS, MSc Ortho

PURPOSE/QUESTION

What is the short- or long-termeffect of orthodontic force on theposition of theminiscrews (MS) usedin orthodontic treatment?

SOURCE OF FUNDING

Information not available

TYPE OF STUDY/DESIGN

Systematic review

LEVEL OF EVIDENCE

Level 2: Limited-quality, patient-oriented evidence

STRENGTH OFRECOMMENDATION GRADE

Grade B: Inconsistent or limited-quality patient-oriented evidence

J Evid Base Dent Pract 2014;14:118-1191532-3382/$36.00� 2014 Elsevier Inc. All rights reserved.http://dx.doi.org/10.1016/j.jebdp.2014.07.001

Modest Evidence Indicates ThatOrthodontic Force Results in PositionalChanges of Orthodontic Miniscrews

SUMMARY

Selection CriteriaPubMed and Scopus databases were searched up to July 2013 for all papersinvestigating the stability of MS. Several combinations of terms were usedfor the MS (mini-implant OR miniscrew OR bone screw AND orthodonticsAND displacement). All research designs except case reports and reviewarticles were included. The articles sought had to have clear study designand reproducible measuring methods for determining the displacementof MS and be published in the English or German language. Sixty-eightarticles were identified; of those, 26 articles met all inclusion and exclusioncriteria. One additional article was retrieved by hand search, for a total of27 articles included in the systematic review.

The included articles were divided into two groups: (1) those investi-gating primary displacement (n = 16), which included 9 in vitro articlesand 7 articles using finite element analysis; and (2) articles investigatingsecondary displacement of MS (n = 11), which included 9 clinical trialsand 2 animal experiments.

Key Study FactorThe key study factor was orthodontic force.

Main Outcome MeasureThe main outcome was either primary (early) displacement of MS (imme-diate displacement after applying force due to bone properties) or second-ary displacement (long-term displacement due to bone remodeling)measured in millimeters.

Main ResultsAll but one of the included studies reported various ranges of primaryand secondary displacement of MS loaded with normal orthodontic force(0.5–2.5 N). The results of the review indicate the diameter of the MS,insertion site, and loading duration as the most important factors deter-mining the amount of displacement. The magnitude of force appearedto play a minor role if it remained within the range of normal orthodonticforces. No difference was found between self-tapping and self-drilling MS.

The most common type of movement was controlled tipping or bodilymovement, with greater displacement of the head area (1.0–4.1 mm) to-ward the side of applied force.

ConclusionsThe authors concluded that the MS offer good anchorage for orthodonticsbiomechanics. Primary displacement was small (#0.1 mm) and clinicallyinsignificant in nearly all studies. However, secondary displacementreached a clinically significant level (mean of 0–2.7 mm, with maximumvalues up to 5.5 mm).

JOURNAL OF EVIDENCE-BASED DENTAL PRACTICE

COMMENTARYANDANALYSIS

The use of MS has dramatically expanded previous ortho-dontic treatment expectations and shifted the quest forproper biomechanics toward a better, easier, and moreefficient procedure in carefully selected cases. However,such advantages should not obscure the necessity for cor-rect treatment planning. In addition, biological limita-tions must be respected and properly evaluated withclose monitoring of any complications that might arise.

In this systematic review, the authors addressedoneof theoverlookedMS complications, namely, displacement of MSunder orthodontic forces. Only 8 uncontrolled trials andone randomized clinical trial provided adequate statistics.

In contrast to conventional dental implants, MS were re-ported to show some positional changes under orthodon-tic forces (0.5–2.5 N).1,2 In addition to bone propertiesand remodeling, such instability might be attributed tothe partial osseointegration observed in MS.3

The authors did not differentiate precisely betweenprimary and secondary displacement in terms of timebecause it is possible for MS to show bony remodelingand tilting at the same time as a result of bone elasticity.Therefore MS might exhibit both types of displacementat the same time and it is not clinically feasible to differen-tiate between the two.

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Two other limitations were noticed. First, only two data-bases were searched (PubMed and Scopus). Second, onlypapers published in English or German were consideredfor review, which may have introduced a language bias.

The authors favored a customized insertion of MS inthe inter-radicular bone away from the direction of forceto avoid root proximity and reduce MS failure rates. Nofurther recommendations were given because of thelack of robust evidence. Further research is needed.

REFERENCES

1. Liou EJ, Pai BC, Lin JC. Dominiscrews remain stationary under ortho-dontic forces? Am J Orthod Dentofacial Orthop 2004;126(1):42-7.

2. Wang YC, Liou EJ. Comparison of the loading behavior of self-drillingand predrilled miniscrews throughout orthodontic loading. Am JOrthod Dentofacial Orthop 2008;133(1):38-43.

3. Deguchi T, Takano-Yamamoto T, Kanomi R, Hartsfield JK Jr,Roberts WE, Garetto LP. The use of small titanium screws for ortho-dontic anchorage. J Dent Res 2003;82:377-81.

REVIEWER

Mohammed Khalil Al-Dhubhani, BDS, MSc OrthoPrivate practice, Al-Nasr Street, Sana’a, Yemen,Tel.: þ967 739375836Dr.mkm@hotmail.com

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