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The Angle Orthodontist Jan 2010To evaluate the quantitative effects on torque expression of varying the slot size of stainless steel orthodontic brackets and the dimension of stainless steel wire, and... (Review)
Review
OBJECTIVE
To evaluate the quantitative effects on torque expression of varying the slot size of stainless steel orthodontic brackets and the dimension of stainless steel wire, and to analyze the limitations of the experimental methods used.
MATERIALS AND METHODS
In vitro studies measuring torque expression in conventional and self-ligating stainless steel brackets with a torque-measuring device, with the use of straight stainless steel orthodontic wire without second-order mechanics and without loops, coils, or auxiliary wires, were sought through a systematic review process.
RESULTS
Eleven articles were selected. Direct comparison of different studies was limited by differences in the measuring devices used and in the parameters measured. On the basis of the selected studies, in a 0.018 inch stainless steel bracket slot, the engagement angle ranges from 31 degrees with a 0.016 x 0.016 inch stainless steel archwire to 4.6 degrees with a 0.018 x 0.025 inch stainless steel archwire. In a 0.022 inch stainless steel bracket slot, the engagement angle ranges from 18 degrees with a 0.018 x 0.025 inch stainless steel archwire to 6 degrees with a 0.021 x 0.025 inch stainless steel archwire. Active stainless steel self-ligating brackets demonstrate an engagement angle of approximately 7.5 degrees, whereas passive stainless steel self-ligating brackets show an engagement angle of approximately 14 degrees with 0.019 x 0.025 inch stainless steel wire in a 0.022 inch slot.
CONCLUSIONS
The engagement angle depends on archwire dimension and edge shape, as well as on bracket slot dimension, and is variable and larger than published theoretical values. Clinically effective torque can be achieved in a 0.022 inch bracket slot with archwire torsion of 15 to 31 degrees for active self-ligating brackets and of 23 to 35 degrees for passive self-ligating brackets with a 0.019 x 0.025 inch stainless steel wire.
Topics: Dental Alloys; Humans; Materials Testing; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Stainless Steel; Surface Properties; Torque; Torsion, Mechanical
PubMed: 19852662
DOI: 10.2319/080508-352.1 -
The Angle Orthodontist May 2009To compare the amount of expressed frictional resistance between orthodontic self-ligating brackets and conventionally ligated brackets in vitro as reported in the... (Comparative Study)
Comparative Study Review
OBJECTIVE
To compare the amount of expressed frictional resistance between orthodontic self-ligating brackets and conventionally ligated brackets in vitro as reported in the literature.
METHODS
Several electronic databases (Medline, PubMed, Embase, Cochrane Library, and Web of Science) were searched without limits. In vitro studies that addressed friction of self-ligating brackets compared with conventionally ligated brackets were selected and reviewed. In addition, a search was performed by going through the reference lists of the selected articles to identify any paper that could have been missed by the electronic searches.
RESULTS
A total of 70 papers from the electronic database searches and 3 papers from the secondary search were initially obtained. After applying the selection criteria, only 19 papers were included in this review. A wide range of methods were applied.
CONCLUSIONS
Compared with conventional brackets, self-ligating brackets produce lower friction when coupled with small round archwires in the absence of tipping and/or torque in an ideally aligned arch. Sufficient evidence was not found to claim that with large rectangular wires, in the presence of tipping and/or torque and in arches with considerable malocclusion, self-ligating brackets produce lower friction compared with conventional brackets.
Topics: Friction; Humans; Orthodontic Brackets; Orthodontic Wires; Surface Properties; Torque
PubMed: 19413397
DOI: 10.2319/060208-288.1 -
The Angle Orthodontist Jan 2009To evaluate the effectiveness of adhesives used to attach bands to teeth during fixed appliance treatment. (Review)
Review
OBJECTIVE
To evaluate the effectiveness of adhesives used to attach bands to teeth during fixed appliance treatment.
MATERIAL AND METHODS
Electronic databases, conference proceedings and the Internet were searched. There was no restriction with regard to publication status or language of publication. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) (including split-mouth studies) of adhesives used to attach orthodontic bands to molar teeth were selected. Patients with full arch fixed orthodontic appliance(s) who had bands attached to molars were included. All review authors were involved in study selection, validity assessment, and data extraction. Disagreements were resolved by discussion. Comparisons were made between the main types of adhesive.
RESULTS
Five RCTs and three CCTs were identified, all of split-mouth design. Four trials compared chemically cured zinc phosphate and chemically cured glass ionomer; three trials compared chemically cured glass ionomer cement with light-cured compomer; and one trial compared chemically cured glass ionomer with a chemically cured glass polyphosphonate. Data analysis was often inappropriate within the studies. Meta-analysis was not feasible.
CONCLUSIONS
There is insufficient high-quality evidence with regard to the most effective adhesive for attaching orthodontic bands to molar teeth. Further RCTs are required.
Topics: Compomers; Controlled Clinical Trials as Topic; Dental Cements; Glass Ionomer Cements; Humans; Light-Curing of Dental Adhesives; Molar; Organophosphates; Orthodontic Wires; Self-Curing of Dental Resins; Zinc Phosphate Cement
PubMed: 19123702
DOI: 10.2319/081307-377.1