Twenty-six subjects (39 Molars) who presented with at least one extracted mandibular first molar were selected to participate in the study. The subjects were subdivided into one of 3 groups as follows: group 1 consisted of 18 molars (13 molars from patients with bilateral first molar extraction space and 5 molars from patients with unilateral first molar extraction space) where piezocision was performed immediately before molar protraction; group 2 consisted of 21 molars (13 from patients with bilateral first molar extraction space and 8 molars from patients with unilateral first molar extraction space) where molar protraction was performed with no piezocision; group 3 consisted of 21 molars (group 2 subjects where piezocision was carried on after 3 months of molar protraction with no piezocision. After reaching 0.019X0.025" SS arch wire, NiTi coil spring was used for space closure (protraction force was 150g) attached from the lower second molar hook to the head of the mini-screw. Piezocision was performed by making 2 vertical incisions mesial and distal to the extraction space. Piezotome was inserted in the incisions previously made and bone cuts were done with a length up to mucogingival line and depth of 3 mm.
Gingival crevicular fluid (GCF) sample was obtained from the mesiogingival side of the lower second permanent molar with use of Periopaper. GCF sample was repeated 1 day, 1 week and 4 weeks after molar protraction with piezocision or with no piezocision. Pain was assessed using visual analog scale (VAS). Patients were requested to report the level of pain for 7 consecutive days.