[Accuracy rate of clinical diagnosis of disc displacement without reduction in temporomandibular joint using MRI]

Internal derangement [ID] of TMJ is the most common type of temporomandibular disorders after muscle disorders and includes all disorders related to incoordination and dislocation of disc and condyle. Anterior disc displacement without reduction or closed lock will happen if the disc or condyle displaces severely or if the disc traps in the space in front of the condyle accompanied with reduction in maximum mouth Opening. The purpose of this study was to evaluate reliability of clinical diagnosis of disc displacement without reduction [closed lock] by using magnetic resonance imaging as the Gold standard. This cross-sectional study was carried out on 10 patients who had referred to Dental school of Mashhad University with the symptoms of ID and were assigned a clinical diagnosis of disc displacement without reduction. Sagital and coronal MR images were obtained with 0.5 Tesla magnetic resonance system, with the jaw in closed and maximum opening position subsequently to establish the corresponding diagnosis of disc-condyle relationship. The data analysis included kappa statistic and calculation of positive predictive values and sensitivity. The overall diagnostic agreement for disc displacement without reduction was 0.22 with a corresponding kappa value. The predictive value for clinical diagnosis of disc displacement without reduction was 20% and the sensitivity was 100%. According to the results, clinical diagnostic criteria for disc displacement without reduction is not reliable and patients assigned clinical TMJ-related diagnosis of disc displacement without redaction may need to be supplemented by evidence from MRI to determine the functional disc - condyle relationship

Evaluation of the effect of four current Iranian processing solutions on the image quality of two dental X-ray films

The combination of different processing solutions and dental film types can affect sensitometric properties [density and contrast]. The aim of this study was to determine the effect of 4 currently used Iranian processing solutions on the image quality of 2 types of dental films. In this experimental-laboratory study, a casted mandibular 2nd premolar along with a step wedge was used, to obtain 248 periapical radiographs during 10 working-days. All films were processed in four Iranian processing solutions: Teifsaz, Jahan, Farhan and Champion. Endodontic files were used to assess the diagnostic accuracy, Densitometric evaluation of the lead wedge radiographs was done at the Atomic Energy Organization of Iran using an Iranian digital software densitometry. Data were analyzed using the ANOVA test. The mean density and contrast of the Kodak images was significantly higher than the Agfa images [P=0.001], Films processed with Champion solution revealed the highest radiographic contrast [P=0.001]. No significant difference was found between the Agfa and Kodak films in determining the position of the endodontic file [P>0.05]. This study showed that the type of processing solution and film can significantly affect radiographic density and, contrast. Kodak films processed in Champion solution revealed the highest radiographic density among the studied materials