Effectiveness of en masse versus two-step retraction: a systematic review and meta-analysis

Abstract

BackgroundThis review aims to compare the effectiveness of en masse and two-step retraction methods during orthodontic space closure regarding anchorage preservation and anterior segment retraction and to assess their effect on the duration of treatment and root resorption.MethodsAn electronic search for potentially eligible randomized controlled trials and prospective controlled trials was performed in five electronic databases up to July 2017. The process of study selection, data extraction, and quality assessment was performed by two reviewers independently. A narrative review is presented in addition to a quantitative synthesis of the pooled results where possible. The Cochrane risk of bias tool and the Newcastle-Ottawa Scale were used for the methodological quality assessment of the included studies.ResultsEight studies were included in the qualitative synthesis in this review. Four studies were included in the quantitative synthesis. En masse/miniscrew combination showed a statistically significant standard mean difference regarding anchorage preservation − 2.55 mm (95% CI − 2.99 to − 2.11) and the amount of upper incisor retraction − 0.38 mm (95% CI − 0.70 to − 0.06) when compared to a two-step/conventional anchorage combination. Qualitative synthesis suggested that en masse retraction requires less time than two-step retraction with no difference in the amount of root resorption.ConclusionsBoth en masse and two-step retraction methods are effective during the space closure phase. The en masse/miniscrew combination is superior to the two-step/conventional anchorage combination with regard to anchorage preservation and amount of retraction. Limited evidence suggests that anchorage reinforcement with a headgear produces similar results with both retraction methods. Limited evidence also suggests that en masse retraction may require less time and that no significant differences exist in the amount of root resorption between the two methods.Electronic supplementary materialThe online version of this article (10.1186/s40510-017-0196-7) contains supplementary material, which is available to authorized users.

A cost-effectiveness analysis of anchorage reinforcement with miniscrews and molar blocks in adolescents: a randomized controlled trial

“…10,11 In these cases, extraction of the maxillary first premolars followed by en masse retraction of the maxillary anterior teeth is a well-established treatment concept. 12 However, this concept often requires anchorage reinforcement. Anchorage can be reinforced with different techniques: A very convenient way to reinforce anchorage is to unite several teeth to an anchorage block.…”

Comparison of Frictional Resistance in Conventional Brackets with Different Stainless Steel Wires

“…The wires' dimensions considered in the study were with the purpose of evaluating appropriate wire for individual canine retraction. The study by Rizk et al 9 stated that both en masse and two-step retraction methods are effective during the space closure phase with regard to anchorage preservation and amount of retraction.…”

“…2 Both en masse/miniscrew combination and twostep retraction combined with a conventional anchorage are used in maximum anchorage cases. 9 The study was undertaken to find a round wire of lower friction for individual canine retraction in critical anchorage cases. The objective of taking rectangular wire was to compare the difference in friction among all the three wires.…”

Effectiveness of orthodontic temporary anchorage devices in canine retraction and anchorage preservation during two-step technique: A systematic review and meta-analysis

“…Two-step retraction and en masse retraction are two methods for achieving extraction space closure 15,16 . Both techniques are efficient for space closure, and there is no significant difference between the two methods in the extent of anterior tooth retraction or molar anchorage loss 5,15,17 .…”