The effect of temporomandibular joint dysfunction on the craniocervical mandibular system: A retrospective study.

BACKGROUND: Temporomandibular disorders are the most common condition affecting the orofacial region, resulting in pain and dysfunction. OBJECTIVE: This study aimed to elucidate the ambiguous association between cervical features and temporomandibular disorders by measuring the rotations between the skull-atlas, atlas-axis and mandible-atlas and examining the relationship between these rotations and temporomandibular disorders. METHODS: Cone-beam computed tomography (CBCT) images from 176 patients, 97 females and 79 males with an average age of 25.7 years were used in this study. The patients were divided into two groups: those with joint dysfunction (n = 88) and those without (n = 88). The study employed various methods to determine rotations in the skull-atlas, atlas-axis and mandible atlas based on anatomical landmarks and measurements. These methods include the use of specific planes, angles and distances to identify and measure rotation. Data analysis was performed using the TURCOSA statistical software (Turcosa Analytics Ltd Co, Turkey, www.turcosa.com.tr). RESULTS: The results showed that the degree of rotation between the skull and the atlas was higher in the TMD group than in the control group (p < .001). Similarly, Atlas-axis rotation was significantly higher in the TMD group (p < .001). However, no significant difference was found between mandible atlas rotations in the two groups (p = .546). The study also found a significant difference between the direction of rotation between the atlas and axis and the direction of mandible atlas rotation (p < .001) as well as between skull and atlas rotations and mandible-atlas rotations (p < .001). CONCLUSION: Overall, the study suggests that there is a relationship between the skeletal structures of the cranio-cervico-mandibular system and TMD. Skull-atlas and atlas-axis rotations may play an important role in the aetiology of TMD in individuals with TMD. Therefore, it is important to evaluate rotations in the skull-atlas-axis region for the treatment of TMD.

Comparison of skeletal and dental effects of two different tooth-tissue-borne types of rapid maxillary expansion appliances: A CBCT retrospective study.

OBJECTIVES: To compare the skeletal and dental effects of different types of rapid maxillary expansion (RME) appliances using cone-beam computed tomography (CBCT). MATERIALS/METHODS: This multi-centre study was conducted with a total of 56 patients. The sample consisted of two groups including the McNamara-Type RME (MNR) group with 30 patients (16 females, 14 males, mean age: 13.38 ± 1.16 years) and Full-Coverage RME (FCR) group with 26 patients (10 females, 16 males, mean age:13.78 ± 1.06 years). Twenty-one parameters were measured on CBCT images including 4 maxillary skeletal, 12 maxillary alveolar, and 5 maxillary dental measurements, and the data were analysed using the SPSS 20.0 software. RESULTS: The rates of increase in the palatal maxillary width (PMW) (3), PMW(4), and PMW(6) were significantly higher in the MNR group (P < .05). While the rates of increase in the buccal maxillary width (BMW) (3) and BMW(4) were statistically higher in the MNR group, the rate of increase in BMW (6) was higher in the FCR group (P < .05). The increases in HPW (4), HPW (6), PAA4(°), and PAA6(°), which are parameters about hard palate width (HPW) and palatal alveolar angle (PAA), were also significantly higher in the MNR group (P < .05). The increases in PAW (4) and PAW (6), referring to the widths between the palatal root apices were significantly higher in the MNR group (P < .05).The increase in Slope-6(°) was also higher in the MNR group (P < .05). CONCLUSION: Expansion in the palatal region on the alveolar level was higher in MNR than in FCR, while expansion in FCR was the highest in the posterior. In both appliances, there was tipping in the buccal direction in both alveolar bone and teeth, and the rate of this tipping was higher in MNR.