Morphological evaluation of gonial and antegonial regions in bruxers on panoramic radiographic images.

BACKGROUND: This is the first study to report both cortical and trabecular bone evaluation of mandibles in bruxers, within the knowledge of the authors. The purpose of this study was to evaluate the effects of bruxism on both the cortical and the trabecular bone in antegonial and gonial regions of the mandible, which is the attachment of the masticatory muscles, by using panoramic radiographic images. METHODS: In this study, the data of 65 bruxer (31 female, 34 male) and 71 non-bruxer (37 female, 34 male) young adult patients (20-30 years) were evaluated. Antegonial Notch Depth (AND), Antegonial-Index (AI), Gonial-Index, Fractal Dimension (FD) and Bone Peaks (BP) were evaluated on panoramic radiographic images. The effects of the bruxism, gender and side factors were investigated according to these findings. The statistical significance level was set atP ≤ 0.05. RESULTS: The mean AND of bruxers (2.03 ± 0.91) was significantly higher than non-bruxers (1.57 ± 0.71; P < 0.001). The mean AND of males was significantly higher than females on both sides (P < 0.05). The mean AI of bruxers (2.95 ± 0.50) was significantly higher than non-bruxers (2.77 ± 0.43; P = 0.019). The mean FD on each side was significantly lower in bruxers than in non-bruxers (P < 0.05). The mean FD of males (1.39 ± 0.06) was significantly higher than females (1.37 ± 0.06; P = 0.049). BP were observed in 72.5% of bruxers and 27.5% of non-bruxers. The probability of existing BP, in bruxers was approximately 3.4 times higher than in non-bruxers (P = 0.003), in males was approximately 5.5 times higher than in females (P < 0.001). CONCLUSION: According to the findings of this study, the morphological differences seen in cortical and trabecular bone in the antegonial and gonial regions of the mandible in bruxers can be emphasized as deeper AND, higher AI, increased of existing BPs, and lower FD, respectively. The appearance of these morphological changes on radiographs may be useful for indication and follow-up of bruxism. Gender is an effective factor on AND, existing BP and FD.

A radiological evaluation of the effects of edentulousness on the temporomandibular joint.

BACKGROUND: The articular eminence of the temporomandibular joint is an anatomical structure exposed to functional loads resulting from masticatory forces. Tooth loss may change the biomechanics of the masticator system, and the articular eminence can be affected by this change. OBJECTIVE: The aim of this study is to examine the relationship between the edentulousness and the articular eminence inclination of the temporomandibular joint. METHODS: The articular eminence inclination was measured in panoramic radiographs in the right and left temporomandibular joint on a total of 100 patients (50 dentate and 50 edentulous). The articular eminence inclination of dentate and edentulous patients was compared, as well as the influence of gender and duration of edentulousness. RESULTS: The mean articular eminence inclination value in the dentate group (42.6 ± 4.30 ) was higher than that of the edentulous group (35.1 ± 4.70 , P < .001). Although there was no significant difference between males and females in the dentate group with regard to articular eminence inclination (42.0 ± 4.70 and 42.9 ± 4.10 , respectively, P = .373), in the edentulous group, males had higher values as compared to females (37.1 ± 4.70 and 34.2 ± 4.50 , respectively, P = .003). Finally, the duration of edentulousness and the degrees of articular eminence inclination values did not show positive correlations (P = .782). CONCLUSION: According to the results of this study, we found that edentulous patients had lower articular eminence inclination than dentate patients, and it was more prominent in female than male patients.

The effect of 1.5 T and 3 T magnetic resonance imaging on microleakage of amalgam restorations.

The aim of this article is to compare the effects of 1.5 T and 3 T MRI on microleakage of amalgam restorations. A total of 90 extracted molar teeth were used in this study. Amalgam was used to restore standard Class V preparations (5 × 3 × 2 mm). Following the restoration, the teeth were divided into three groups according to magnetic resonance imaging (MRI) protocol (Group I: Control, Group II: 1.5 T MRI, and Group III: 3 T MRI). A total of 6,000 thermal cycles at 5°C-55°C were applied on all samples. Microleakage values were measured in millimeters using the ImageJ program. Microleakage values were higher in the gingival region compared to the occlusal region in all groups and the differences were statistically significant (p < .05). Microleakage values were not statistically different among the groups in the occlusal region (p > .05), while there were statistically significant differences among the groups with respect to microleakage values in the gingival region (p < .01). The highest mean microleakage amount in the gingival region was measured in Group III (1.192 ± 0.941 mm). This was followed by Group II (0.519 ± 0.813 mm) and Group I (0.347 ± 0.726 mm), respectively. Within the limitations of this in vitro study, we observed that higher microleakage values in amalgam restored teeth in which were exposed to MRI procedure. We also found that the teeth exposed to the stronger magnetic field showed higher microleakage amount.

CT Imaging of Craniofacial Fibrous Dysplasia.

Fibrous dysplasia is a benign fibroosseous bone dysplasia that can involve single (monostotic) or multiple (polyostotic) bones. Monostotic form is more frequent in the jaws. It is termed as craniofacial fibrous dysplasia, when it involves, though rarely, adjacent craniofacial bones. A 16-year-old girl consulted for a painless swelling in the right posterior mandible for two years. Panoramic radiography revealed ground-glass ill-defined lesions in the three different regions of the maxilla and mandible. Axial CT scan (bone window) showed multiple lesions involving skull base and facial bones. Despite lesions in the skull base, the patient had no abnormal neurological findings. The lesion was diagnosed as fibrous dysplasia based on radiological and histopathological examination. In this paper, CT findings and differential diagnosis of CFD are discussed. CT is a useful imaging technique for CFD cases.