Incremental increase in percentage mouth opening after coronoidectomy in temporomandibular joint ankylosis.

The aim of this study was to evaluate the incremental improvement in mouth opening following coronoidectomy. Twenty-three patients with unilateral temporomandibular joint (TMJ) ankylosis (Sawhney types I-III) were assessed preoperatively; physical and radiological examinations were done (panoramic radiography and computed tomography). Data including demographic and clinical parameters were recorded. Patients with bilateral ankylosis, recurrent cases, and those with Sawhney type IV TMJ ankylosis were not included. The improvement in mouth opening was measured after ostectomy, after ipsilateral coronoidectomy, and after contralateral coronoidectomy. The improvements in mouth opening at each stage were analysed using the Student's t-test and Pearson's correlation coefficient. There was a marked improvement in maximal incisal opening (MIO) from 5.7 ± 4.2mm to 23.7 ± 5.9 mm after removal of the ankylotic bony mass. MIO was significantly increased after ipsilateral coronoidectomy (31.6 ± 7.4mm), and after contralateral coronoidectomy, a mean MIO of 39.4 ± 11.2mm was achieved. At more than 1 year of follow-up, all patients showed improved mouth opening. In conclusion, coronoidectomy plays an important role in improving mouth opening in the treatment of TMJ ankylosis.