Prolonged Missing of Molar Teeth and Risk of Temporomandibular Joint Disorders

Aim: The aim of this study was to determine the relationship between prolonged missing molar(s) (PMM) as a whole and each molar separately and the temporomandibular joint disorders (TMD) with third molars excluded. Patients and Methods: one hundred and twenty participants were divided into two groups, 40 TMD patients of study group (SG) diagnosed by MRI or CT scan and Arthography, 80 asymptomatic volunteers of control group (CG); Both SG and CG were subdivided into three subgroups: (1) prolonged missing molar (PMM) patients with missing of molars for ten years or more; (2) recently missing molar (RMM) patients with missing of molars less than ten years; and (3) no missing molars (NMM) patients with no missing of molars. PMM of SG and CG were divided into five pairs; (pair 1) PMM of SG and CG; (pair 2) prolonged missing (PM) of 16 and/or 26 of SG and CG; (pair 3) PM of 17 and/or 27 of SG and CG; (pair 4) PM of 36 and/or 46 of SG and CG; (pair 5) PM of 37 and/or 47 of SG and CG. Results: (1) Study group SG (a) NMM 28 patients (b) PMM 8 patients (c) RMM 4 patients. (2) Control group CG (a) NMM 66 volunteers (b) PMM 4 volunteers (c) RMM 10 volunteers. (Pair 1) PMM of SG 8 patients (20%) and CG 4 volunteers (5%) (Pair 2) prolonged missing (PM) of 16 and / or 26 of SG 2 (5%) and CG 2 (2.5%) (Pair 3) PM of 17 and/or 27 of SG 1 (2.5%) and CG 0 (0%) (Pair 4) PM of 36 and/or 46 of SG 6 (15%) and CG 1 (1.25%) (Pair 5) PM of 37 and/or 47 of SG 1 (2.5%) and CG 3 (3.75%) Conclusions: Missing of molar teeth for ten years or more may contribute to TMD. Furthermore, the effect of prolonged missing of mandibular first molar(s) may increase the contribution to TMD. When both opposing molars were missing, tilting of distal molars towards the edentulous spaces may be more compared with the presence of the opposing molar.