Influence of orthodontic premolar extraction therapy on the eruption of the third molars: A systematic review of the literature.

BACKGROUND: Through a systematic literature review, the authors assess the effect of premolar extractions on third-molar (M3) eruption considering eruption rate, retromolar space, and molar angulation. TYPES OF STUDIES REVIEWED: The authors performed a systematic search using MEDLINE and Web of Science databases up through April 2017 to identify quality studies available comparing M3 eruption between a group with premolar extraction and a group without premolar extraction. RESULTS: Twelve comparative retrospective cohort studies met all the inclusion criteria. The authors found in 5 studies comparing the rate of M3 eruption that there were significantly higher results in the group with extractions. They found in 5 studies comparing the evolution of the retromolar space significantly higher results in the group with extractions. Lastly, concerning the uprighting of the M3 during treatment, the authors found only 2 studies showing significant differences between the 2 groups, each time in favor of the group with extractions. CONCLUSIONS AND PRACTICAL IMPLICATIONS: The dental literature on premolar extraction related to the eruption of the M3 is composed of average-quality retrospective studies. Premolar extraction significantly improves the chances of M3 eruption, but the level of evidence of comparative retrospective cohort studies is low. Clinicians must continue to rely on their judgment regarding premolar extraction on a case-by-case basis until the evidence is stronger. Retrospective studies with standardized protocols and more detailed methodologies are required to obtain higher levels of evidence.

[Effectiveness of selective alveolar decortication in accelerating orthodontic treatment: a systematic review]. / Efficacité des techniques de décortication alvéolaire sélective dans l'accélération du traitement orthodontique : une revue systématique de la littérature.

INTRODUCTION: The number of scientific publications on accelerating orthodontic treatment, and especially surgical alveolar corticotomies techniques, has grown exponentially over the years. The objective of this systematic literature review was to assess the effectiveness of these corticotomies basing on human studies. MATERIAL AND METHOD: The review was conducted from Medline and Web of Science Core Collection to identify prospective controlled clinical trials with duration of orthodontic treatment or the tooth movement rate for primary endpoint. RESULTS: Eleven studies respected all inclusion criteria. Six investigated the duration of treatment and found shorter values in experimental group than in control group, with a gain of 8 to 34 weeks. Five investigated the tooth movement rate and found 2.3 times higher values on average during the first month in experimental groups, 1.9 times during the second and third months, and 1.3 times during the fourth month. The technique also seemed to decrease the risk of root resorption and improve molar anchorage. Moreover, it exhibited good periodontal tolerance. CONCLUSION: Current literature highlights the effectiveness of surgical decortications during the first three to four months after surgery. Longer prospective studies are needed to assess their long term effects.