Evaluation of piezocision and laser-assisted flapless corticotomy in the acceleration of canine retraction: a randomized controlled trial

Abstract

Background: To evaluate the effectiveness of two minimally invasive surgical procedures in the acceleration of canine retraction: piezocision and laser-assisted flapless corticotomy (LAFC).

Methods: Trial design: A single-centre randomized controlled trial with a compound design (two-arm parallel-group design and a split-mouth design for each arm).

Participants: 36 Class II division I patients (12 males, 24 females; age range: 15 to 27 years) requiring first upper premolars extraction followed by canine retraction.

Interventions: piezocision group (PG; n = 18) and laser-assisted flapless corticotomy group (LG; n = 18). A split-mouth design was applied for each group where the flapless surgical intervention was randomly allocated to one side and the other side served as a control side.

Outcomes: the rate of canine retraction (primary outcome), anchorage loss and canine rotation, which were assessed at 1, 2, 3 and 4 months following the onset of canine retraction. Also the duration of canine retraction was recorded. Random sequence: Computer-generated random numbers. Allocation concealment: sequentially numbered, opaque, sealed envelopes. Blinding: Single blinded (outcomes' assessor).

Results: Seventeen patients in each group were enrolled in the statistical analysis. The rate of canine retraction was significantly greater in the experimental side than in the control side in both groups by two-fold in the first month and 1.5-fold in the second month (p < 0.001). Also the overall canine retraction duration was significantly reduced in the experimental side as compared with control side in both groups about 25% (p ≤ 0.001). There were no significant differences between the experimental and the control sides regarding loss of anchorage and upper canine rotation in both groups (p > 0.05). There were no significant differences between the two flapless techniques regarding the studied variables during all evaluation times (p > 0.05).

Conclusions: Piezocision and laser-assisted flapless corticotomy appeared to be effective treatment methods for accelerating canine retraction without any significant untoward effect on anchorage or canine rotation during rapid retraction.

Trials registration: ClinicalTrials.gov (Identifier: NCT02606331 ).

Keywords: Acceleration; Canine retraction; Flapless corticotomy; Laser-assisted; Minimally invasive surgical procedures; Piezocision.

Fig. 1

a: Soft-tissue incision using blade no 15. b: Vertical cortical cuts using a piezosurgery knife

Fig. 2

Application of perforations using the ER:YAG laser fiber tip. a: Soft-tissue perforations as a first step. b: Hard-tissue alveolar cortical perforations

Fig. 3

Canie retraction stage using NiTi closed coil springs immediatly following flapless corticotomy. a: Piezocision group. b: Laser-assisted flapless corticotomy group

Fig. 4

Landmarks used on plaster models for the analysis. 1: medial end of right third palatal ruga, 2: medial end of left third palatal ruga, 3: cusp tip of right canine, 4: cusp tip of left canine, 5: mesial margin of right canine, 6: mesial margin of left canine, 7: distal margin of right canine, 8 distal margin of left canine, 9: central fossa of maxillary right first permanent molar, 10: central fossa of maxillary left first permanent molar, 11: Mid-palatal suture line

Fig. 5

Measurements on the digital photographs with the help of AudaxCeph

Fig. 6

CONSORT Participants’ flow diagram

Fig. 7

Comparison the duration of canine retraction (months) between two experimental sides in both groups