Effects of unilateral posterior missing-teeth on the temporomandibular joint and the alignment of cervical atlas

Abstract

Cervical atlas alignment changes are associated with craniofacial development. Disturbance of craniofacial development may be associated with temporal mandibular joint function. Therefore, we examined the possibility of a correlation between unilateral missing teeth and morphologic changes of the spine and posture. We collected eighty-nine patients (38 men and 51 women) with unilateral posterior missing teeth and twenty patients without previous orthodontic treatment or missing posterior teeth by tracing and analyzing their panoramic and cephalometric film. We measured the angulations of articular eminence, cranio-cervical angle, and the percentage of the occlusal plane passing through the first and second cervical vertebrae with other morphologic geometric data. The angle of articular eminence inclination was higher in the non-missing teeth group than the missing teeth group (46.66° and 42.28°, respectively). The cranio-cervical angle was smaller in the missing posterior teeth group than the non-missing posterior teeth group (99.81° and 103.27°, respectively). The missing teeth group also showed fewer occlusal planes passing through the intersection of the first and second cervical vertebrae compared to the non-missing teeth group (28.9% and 65%, respectively). Individuals with unilateral missing teeth had lower articular eminence inclination, smaller cranio-cervical angle, and a lower percentage of the occlusal plane passing through the intersection of the first and second cervical vertebrae.

Factors influencing the articular eminence of the temporomandibular joint (Review)

“…The height of the articular eminence (AEH) and the inclination of the articular eminence (AEI) adjust the pathways of the TMJ condyle-disk complex, leading the way the mandible moves (14,(31)(32)(33)(34)(35)(36)(37). The inclination of the AE is appreciated in relation to the Frankfort horizontal plane (12) and it influences the path of condylar movement and the degree of rotation of the disk over the condyle (12,13,33).…”

“…Edentulism may cause modifications in the masticatory biomechanics, which may lead consequently to changes in the AE ( 23 , 32 , 49 , 53 , 54 ). Several research groups described finding reduced AEI values in edentate patients compared to dentate ones ( 23 , 32 , 49 , 53 , 54 ).…”

“…Edentulism may cause modifications in the masticatory biomechanics, which may lead consequently to changes in the AE ( 23 , 32 , 49 , 53 , 54 ). Several research groups described finding reduced AEI values in edentate patients compared to dentate ones ( 23 , 32 , 49 , 53 , 54 ). Recently, an analysis of the effects of edentulism on the TMJ determined lower mean AEI in orthopantomograms of edentulous subjects compared to panoramic radiographs of dentate participants in the study ( 23 ).…”

“…Similarly, in another study, lower angulations of the AE were reported in completely edentulous patients compared to subjects in which dental occlusion was still present ( 53 ). Interestingly, AEI might suffer modifications even when there is a single missing tooth ( 32 ). Thus, decreased AEI were measured in patients with unilateral tooth loss than in the non-missing teeth subjects ( 32 ).…”

“…Interestingly, AEI might suffer modifications even when there is a single missing tooth ( 32 ). Thus, decreased AEI were measured in patients with unilateral tooth loss than in the non-missing teeth subjects ( 32 ). Furthermore, another study analyzing the unilateral missing-tooth effect on the AEI recorded slightly reduced (but not statistically significant reduced) AEI values on the side of unilateral posterior edentulism compared with the side where all the teeth were present (P>0.05) ( 49 ).…”