Clinical outcome of enmasse retraction as compared to two-step retraction in bimaxillary protrusion patients: A systematic review

Space closure is a challenging process that requires thorough understanding of biomechanics to avoid any undesirable tooth movements. In sliding mechanics; two-step retraction (TSR) and en-masse retraction (ER) are the two basic strategies for closing extraction spaces. No other systematic review has compared the magnitude of incisor retraction, pain, discomfort, amount of root shortening and time taken for space closure between the two techniques. The objective of this systematic review was to evaluate and compare the degree of anchor loss, time taken for space closure, amount of root resorption, anterior incisor retraction, success rate, patient compliance and aesthetic changes between TSR and ER. Only RCTs were incorporated with inclusion criteria as patients between 10 to 40 years of age undergoing orthodontic treatment with class I and II malocclusions requiring first premolar extraction with absolute or maximum anchorage plan. Seven RCTs have been included in the qualitative synthesis of the review. ER using mini-screws showed a statistically significant difference in anchorage preservation, amount of incisor retraction and time taken for space closure. Anchorage loss between ER and TSR is not significant. However, the time taken for TSR is 1.8 to 2.2 times more than ER and the anchorage control is better provided by mini-screw assisted ER than conventional systems. Pain and discomfort experienced by the patients using mini-screws were initially higher and the amount of root resorption shows no vivid difference in both the techniques.