Evaluation of condylar positions in patients with temporomandibular disorders: A cone-beam computed tomographic study

PURPOSE: This study was performed to compare the condylar position in patients with temporomandibular joint disorders (TMDs) and a normal group by using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: In the TMD group, 25 patients (5 men and 20 women) were randomly selected among the ones suffering from TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The control group consisted of 25 patients (8 men and 17 women) with normal temporomandibular joints (TMJs) who were referred to the radiology department in order to undergo CBCT scanning for implant treatment in the posterior maxilla. Linear measurements from the superior, anterior, and posterior joint spaces between the condyle and glenoid fossa were made through defined landmarks in the sagittal view. The inclination of articular eminence was also determined. RESULTS: The mean anterior joint space was 2.3 mm in the normal group and 2.8 mm in the TMD group, respectively. The results showed that there was a significant correlation between the superior and posterior joint spaces in both the normal and TMD groups, but it was only in the TMD group that the correlation coefficient among the dimensions of anterior and superior spaces was significant. There was a significant correlation between the inclination of articular eminence and the size of the superior and posterior spaces in the normal group. CONCLUSION: The average dimension of the anterior joint space was different between the two groups. CBCT could be considered a useful diagnostic imaging modality for TMD patients.

effect of full crown preparation on normal and inflamed pulp tissue: an animal study

Full crown preparation may have adverse effects on pulp tissue. In this study, the effect of full-crown preparation on intact versus inflamed pulp tissue was studied. Fifteen healthy mature cats were randomly selected for this study. The study was performed on four canine teeth of each cat. Cats were anesthetized and then radiographs were taken from the canine teeth. Class V cavities were prepared in cat canine teeth. Soft decayed dentin was placed on the floor of cavities and sealed. After 1 month, all of the samples prepared for crown fabrication. Before crown preparation, an impression was taken in a custom tray. During crown preparation, the remnants of carious dentin were removed and undercuts were sealed by glass-ionomer. After preparation, self-cured acrylic temporary crowns were fabricated in a direct procedure and cemented permanently by glass-ionomer. One week later, teeth of the opposite jaw were prepared in a similar procedure. After 2 months, vital perfusion performed and the pulp tissue was histologically examined. There was no significant difference between 4 groups, regarding to histologic status of the pulp. In healthy lower jaw, inflammation was the most frequent but in the other groups, necrosis was most frequent. Also, there was no significant difference between the upper jaw and the lower jaw groups regarding to the frequency of necrosis and inflammation. There is no significant difference between intact and inflamed groups regarding the frequency of necrosis and inflammation

Mandibular flexure in anterior-posterior and transverse plane on edentulous patients in mashhad faculty of dentistry

Angle and internal position of lateral pterygoid muscle leads to contraction over two half of the mandible in maximum opening and protrusion position so it can affects impression prosthetic procedures. The aim of this study was to evaluate the mandibular flexure in two transverse and antroposterior dimensions. Seventy edentulous patients at Mashhad Faculty of Dentistry as the main group and 50 dentulous patients as the control group were selected. In these patients, transverse dimensions between second molar areas and also canine eminence from one side to another side, and longitudinal dimensions based on the distance between canine to second molar area at centric occlusion and maximum mouth opening were measured. Dimensional differences as the mandibular flexure were measured. The mandibular dimensions in maximum opening and closed mouth were different. Average reduction in transverse dimension on second molar region at maximum mouth opening and closing position were almost equal to -0.0787 mm for target group and 0.7512 mm for control group. On anterior side, averages of these changes were equal to 0.3069 mm for target group and were 0.2254 mm for control group. Transverse dimensions in anterior region at maximum opening position are smaller than the same dimension at closed mouth in edentulous and dentulous patients

[Comparison of internal marginal gap in two methods of inceram coping fabrication]

Dental porcelains have an important role in fabrication of the most beautiful restorations. Biocompatibility and translucency in ceramics make them one of the most agreeable restorative materials. Introduction of inceram system has been considered as a great change in the field of restoration. Inceram is made by two ways including Sprint technique and Conventional Method. The purpose of this study was comparing internal marginal gap in Sprint and conventional Alumina methods for making Inceram copings. In this in vitro study, 60-die resin-base with 6-millimeter length and 5-millimeter diameter in the cervical area were fabricated. They were prepared with a 10-degree, convergence angle and 1-millimeter shoulder width with 90-degree shoulder angle. The specimens were then divided into two groups. Next, in one 30-item group, the cores were prepared via Sprint method and in the other group, via conventional method [Alumina]. After the cores were set, they were cemented by Panavia and for measuring the rate of internal gap, the specimens were examined via optical microscope Olympus BH60 with 1-micron precision. The data were compared statistically by students t-tests [alpha=0.05]. Examining the mean internal gap between two groups, it was revealed that the mean internal gap in the Sprint group [181.6 microns] was greater than Alumina group [114.2 microns] and the difference was significant [P=0.015]. Considering the limitations of this study, marginal adaptation in Sprint method was less than conventional method of core fabricating [Alumina]