A survey on the potential relationships between TMD, possible sleep bruxism, unilateral chewing, and occlusal factors in Turkish university students.

OBJECTIVE: To evaluate whether there is a relationship between possible sleep bruxism (PSB), temporomandibular disorders (TMD), unilateral chewing (UC), and occlusal factors in university students recruited from Cumhuriyet University in Turkey. METHODS: For this cross-sectional survey, 519 (223 males, mean age 21.57 ± 2.3 years, 296 females, mean age 21.02 ± 2 years) university students who admitted to the Department of Oral and Maxillofacial Radiology of the Faculty of Dentistry, Cumhuriyet University for dental care between 2012 and 2014 were selected randomly. Students were asked to complete a questionnaire form including questions about TMD, PSB and UC. Presence and direction of malocclusion were recorded during clinical examination. Chi-square test was used for statistical analysis. RESULTS: It was found that 96.6% of the students with PSB had TMD (p < 0.05). The prevalence of severe TMD was high among students with PSB. There was a significant association between UC, PSB and TMD (p < 0.05). No statistically significant association was found between occlusal factors and PSB and TMD (p > 0.05). CONCLUSION: Sleep bruxism, which heavily depends on self-report, is significantly associated with TMD. Unilateral chewing seems to be a common factor for development of SB and TMD. However, further studies are needed to corroborate this finding. Additionally, this study supports the hypothesis that occlusal factors are not related to self-reported sleep bruxism.

Does proclination of maxillary incisors really affect the sagittal position of point A?

OBJECTIVE: To examine the effect of maxillary incisor proclination due to orthodontic treatment upon the sagittal position of point A and evaluate the effect of this possible movement of point A on sella-nasion-point A (SNA) angle. MATERIALS AND METHODS: A study group was formed from 25 subjects (12 male and 13 female) who had Class II division 2 malocclusion with retroclined upper incisors, and a control group was formed from 25 subjects (12 male and 13 female) who had minor crowding in the beginning of the treatment and required no or minimal maxillary anterior tooth movement. Treatment changes in maxillary incisor inclination, sagittal position of point A, SNA angle, and movement of incisor root apex and incisal edge were calculated on pretreatment and posttreatment lateral cephalographs. RESULTS: Maxillary incisors were significantly proclined (17.33°) in the study group and not significantly proclined (1.81°) in the control group. This proclination resulted in 2.12-mm backward movement of the root apex and 5.76-mm forward movement of the incisal edge of maxillary incisors. Point A moved 1.04 mm backward (P  =  .582) and 0.48 mm (P  =  .811) forward in the study and control groups, respectively. Incisor root apex and incisal edge almost remained stable in the control group. No significant change was observed in the value of the SNA angle in both the study and control groups. CONCLUSIONS: Proclination of maxillary incisors accompanied by backward movement of incisor root apex caused posterior movement of point A. However, this posterior movement does not significantly affect the SNA angle.