فهرست مطالب sepideh rahimian

Objectives :

Canine teeth are supposed to have one single root canal, but they may have some anatomical variations. This study aimed to investigate the morphology of root canals of maxillary and mandibular canines regarding gender and age in an Iranian population using cone-beam computed tomography (CBCT).

Methods:

 Using CBCT images, 126 maxillary and 125 mandibular canines were evaluated. Root anatomy was assessed regarding root length, root curvature, number of roots and canals, and pattern of root canal system. The data were analyzed by the Kruskal Wallis and Mann-Whitney tests and multinomial regression model. 

Results:

 The mean root length of male patients was significantly higher than females (p=0.0001). The most frequent root curvatures were towards the distal and buccal. Mandibular teeth (p=0.020) and females (p=0.012) had higher frequency of root curvature. All maxillary canines had one root; whereas 1.6% of mandibular canines had two roots. High prevalence of two canals was reported (34.9% of maxillary and 18.4% of mandibular canines). The most prevalent canal patterns included type I (65.1%) followed by type III (34.9%) in maxillary canines and types I (81.6%), III (16.8%) and V (1.6%) in mandibular canines. Higher frequency of type III canal configuration was reported in maxillary teeth (p=0.001) and male patients (p=0.008). No significant difference was found in any parameter between different age groups (p>0.05).

Conclusion:

 A high percentage of type III canal configuration in canine teeth especially maxillary canines and male patients was reported. Mandibular teeth and females had higher frequency of root curvature.

With regards to the increasing use of implants in the field of dentistry, the recognition of critical landmarks is essential. Nasopalatine canal (NPC) is one of these important indices, which due to high esthetic expectations in premaxilla, should be precisely evaluated before surgery..
This study aimed to evaluate the morphological and anatomical variations of the NPC..
A total of 326 individual cone beam computed tomography (CBCT) images were analyzed in sagittal, coronal, and axial planes in order to evaluate the dimensions, morphology and anatomic features of the NPC. The canal shape, length, and curvature, incisive and Stenson’s foramina (SF) dimensions, and the number of openings on both sides of the canal were assessed. The correlation of age, gender, and dental status with all considered parameters were analyzed..
The most dominant shape of the NPC was cylindrical (65.33%). The mean NPC length was 12.85 ± 2.63 mm, which was greater in men and showed significant differences between two genders (P This study has highlighted the anatomical variations of NPC regarding its dimension, location and morphological appearance. Cylindrical was the most common shape followed by funnel-shape, hourglass, and spindle, which were the other canal shapes with less frequency, respectively. The results suggest significant relationship between NPC, and gender and dental status. The influence of age was not as significant as gender and dental status..

Different enhancements have been used to improve the diagnostic accuracy of radiographic images in digital systems. However, the diagnostic accuracy of the effects of these enhancement options on dental caries has not been determined.
This study evaluated the effects of software enhancements of zooming, colorization, and contrast conversion on the accuracy of proximal caries detection.
In this diagnostic in vitro trial study, 42 non-cavitated and restoration-free extracted permanent molars and premolars were selected and mounted onto 14 blocks in contact with each other. Radiographic images were obtained from the teeth in similar standardized condition using the paralleling technique. The images were shown without any enhancement or with using the options of zooming, colorization, and contrast conversion. Depth of proximal caries was determined by a radiologist using four-scaled criteria. The diagnostic accuracy of digital images that had undergone different enhancements was calculated by the chi-square test.
The diagnostic odds of the original digital images were lower than 20 (5.7). By using the enhancement options of zooming, colorization, and contrast conversion, the diagnostic odds of the enamel proximal caries had a score of less than 20. The score was higher than 20 for proximal caries located in the outer and inner half of the dentin.
The enhancement options of zooming, colorization, and contrast conversion did not significantly influence the diagnostic accuracy of digital images in enamel caries, but they enhanced caries diagnosis/progression in the outer and inner half of the dentin.

Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms.
Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results.
CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations.

A 52-year-old Caucasian woman suffering from pain in the anterior maxillary region, presented to the clinic. Examination revealed a draining sinus tract in the buccal vestibule of the maxilla in the left anterior segment and expansion in the middle of palate. On conventional radiographic examination the lesion was initially assumed to be a periapical problem related to the incisors but subsequently it was diagnosed to be a bisphosphonate osteonecrosis. Acquiring a comprehensive medical history from the patients, conducting the clinical vitality tests and most importantly being familiar with the non-odontogenic lesions that can be side effects of specific medications are important requirements for reaching a correct diagnosis.