En-masse Retraction of Upper Anterior Teeth in Adult Patients with Maxillary or Bimaxillary Dentoalveolar Protrusion: A Systematic Review and Meta-analysis

To evaluate the efficacy of accelerated and non-accelerated methods of en-masse retraction of the upper anterior teeth in terms of skeletal, dental, and soft-tissue variables, as well as the duration of retraction or overall orthodontic treatment.An electronic search of PubMed and nine other major databases for randomized controlled trials (RCTs) and clinical controlled trials (CCTs) was performed between January 1990 and April 2018. The bibliography in each identified article was reviewed. In addition, manual searching was performed in the same time frame in five major orthodontic journals.The participants were patients over 14 years old undergoing fixed orthodontic treatment with extraction of maxillary or bimaxillary premolars followed by en-masse retraction of maxillary anterior teeth in both groups. Cochrane's risk of bias tool for RCTs and methodological index for non-randomized studies (MINORS) for CCTs were used.Eight articles (six RCTs and two CCTs) were included in this review, and only five articles were suitable for quantitative synthesis. The en-masse retraction caused a decrease in the SNA and ANB angles with no significant differences between the different en-masse retraction methods. Using temporary skeletal anchorage devices (TSADs) gave significantly better results in terms of posterior anchorage in comparison with conventional anchorage(standardized mean difference (SMD) = -3.03 mm, p < 0.001). No significant difference was found between en-masse/flapless corticotomy and en-masse/control groups in terms of anterior teeth retraction (p = 0.661); while there was a significantly greater anterior teeth retraction in corticotomy with flap elevation group compared to control group (p < 0.001).There is a weak to moderate evidence that using accelerated and non-accelerated methods would improve the facial profile and lead to similar skeletal corrections. There is weak to moderate evidence that using TSADs would lead to better posterior anchorage than using conventional anchor-age.Moderate evidence was found regarding the benefit of using piezosurgery in achieving good incisors' inclination. Contradictory results were found regarding the amount of achieved anterior retraction and the retraction time in the studies that evaluated acceleration methods versus the traditional methods of retraction. According to the quality of evidence, there is a need for more well-conducted RCTs, and more work to be oriented towards en-masse retraction with the use of other acceleration methods.The correction of the maxillary or bimaxillary dentoalveolar protrusion by en-masse retraction of the upper anterior teeth with/without acceleration is accompanied by aesthetic results in the facial soft tissues as well as in the underlying skeletal and dental structures. The traditional corticotomy-assisted retraction is expected to reduce the retraction time significantly. However, the strength of evidence is not strong and requires additional research work.