CBCT Findings Of Temporomandibular Joint Space In Adult Patients With Unilateral Mandibular First Molar Missing

Objective: To measure the temporomandibular joint space by cone beam computed tomography(CBCT)and to investigate the effect of long-term unilateral mandibular first permanent molar loss on the temporomandibular joint space.Methods: Thirty adult patients with long-term unilateral mandibular first permanent molar loss were obtained.CBCT scan reconstruction obtained axial,coronal,and sagittal images.Then,the sagittal plane was taken from the transverse axis of the condyle.The temporomandibular jaw was measured by Kamelchuk method.The anterior,superior,and posterior joints were compared with 30 healthy adults(control group)who met the trial design.Results: The anterior space of the unilateral mandibular first permanent molar missing group was significantly larger than the control group [(1.85±0.41)mm],and the unilateral mandibular first permanent molar missing group was absent.The posterior gap(2.24±0.40)mm was smaller than the control group [(2.50±0.38)mm],and the difference was statistically significant.(P<0.05);There was no significant difference between the long-term unilateral mandibular first permanent molar missing group(2.84±0.29mm)and the control joint space(2.90±0.21mm)(P>0.05).Conclusion: Long-term unilateral mandibular first permanent molar loss can narrow the anterior space of the temporomandibular joint and widen the posterior space.