11 research outputs found

    Morphology of the Roots and Canals of Mandibular Third Molars, Their Symmetry and Related Factors Using Cone-Beam Computed Tomography

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    Introduction: Adequate knowledge about the anatomy of the roots and canals of mandibular third molars is imperative for a successful treatment. This study aimed to use cone-beam computed tomography (CBCT) to evaluate the morphology of the roots and canals of mandibular third molars and their symmetry. Methods and Materials: Totally, 110 CBCT images of bilateral mandibular third molars were evaluated in terms of the number of roots and canals, canal type, isthmus location, location of accessory canals, degree of root curvature and its direction, age and sex of patients and the symmetry of variables in the right and left sides of the mandible. The descriptive statistics, t-test and chi-square test were applied to analyze data. Results: Of all, 71.36% of mandibular third molars had two roots, 20.9% had one single root and 7.72% had three roots. The distal root had one single canal in 89.08%. The mesial root had one single canal in 44.25% and two canals in 49.42%. The Vertucci’s types I (45.40%) and IV (34.48%) had the highest frequency in the mesial root while type I (91.95%) had the highest frequency in the distal root. The deviation of mesial root was towards the distal while distal roots were mainly straight. Conclusion: The symmetry between the right and left mandibular third molars was significantly high. In case of encountering anatomical complexities in dental treatment of a mandibular third molar, dental clinicians should consider the high possibility of presence of the same condition in the contralateral mandibular third molar.Keywords: Anatomy; Cone-Beam Computed Tomography; Mandible; Third Mola

    Comparison of Charge-Coupled Devices and Photostimulable Phosphor Storage Plates for Detection of Vertical Root Fractures in Endodontically Treated Teeth: An In Vitro Study

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    Objective: Vertical root fracture (VRF) is among the most common causes of endodontic treatment failures. This study aims to compare charge-coupled devices (CCD) and photostimulable phosphor plates (PSP) for detection of vertical root fractures in endodontically treated teeth.Methods: In this diagnostic in vitro study, 40 maxillary anterior teeth were selected and after preparation and root canal filling, their crowns were cut 2mm above the cementoenamel junction (CEJ). The teeth were embedded in a piece of dried bone and radiographed using CCD and PSP with equal geometry at zero and 15° horizontal angles. VRFs were then induced and the fractured fragments were reattached. The teeth were radiographed again. Three observers evaluated the radiographs for detection of fracture line. Data were analyzed using the Proportion test and Wilcoxon’s Signed Ranks test.Results: No significant difference was found between the two sensors in detection of VRFs [p-value (complete)= 0.592, p-value (absolute)= 1]. The sensitivity of the two sensors for detection of buccolingual and mesiodistal fractures was not significantly different [p-value BL (absolute)= 0.109, p-value BL (complete) 0.180] [p-value MD (complete)=0.593, p-value MD (absolute)= 0.102]. The sensitivity of both sensors for detection of buccolingual fracture was higher than for mesiodistal fractures (p<0.001).Conclusion: CCD and PSP had equal efficacy for detection of VRFs in endodontically treated teeth

    Canal Transportation and Centering Ability of ProTaper and SafeSider in Preparation of Curved Root Canals: A CBCT Evaluation

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    Introduction: Maintaining the original central canal path is an important parameter in efficient root canal preparation. Instruments causing minimal changes in original canal path are preferred for this purpose. This study sought to compare canal transportation and centering ability of ProTaper and SafeSider instruments in curved mesiobuccal root canals of mandibular first molars using cone beam computed tomography (CBCT). Materials and Methods: In this experimental study, 30 mesiobuccal root canals of extracted human mandibular first molars with 20° to 40° curvature were randomly divided into two groups (n=15). After mounting in putty, preoperative CBCT scans were obtained of teeth. Root canals in group A were shaped using S1, S2, F1 and F2 of ProTaper system. Root canals in group B were instrumented to size 25 using SafeSider system according to the manufacturers’ instructions. Postoperative CBCT scans were then obtained. The distance between the external root surface and internal canal wall was measured at the mesial and distal at 1, 3 and 7 mm from the apex. The values measured on primary and secondary CBCT scans were compared to assess possible changes in original central canal path and canal transportation. Data were compared using the t-test and repeated measure ANOVA. Results: ProTaper and SafeSider were significantly different in terms of canal transportation and centering ability, and ProTaper was significantly superior to SafeSider in this respect (P<0.001). Conclusion: ProTaper (in contrast to SafeSider) is well capable of maintaining the original central canal path with the least amount of transportation.Keywords: Canal Transportation; Cone-beam Computed Tomography; ProTaper; Root Canal Preparation; SafeSide

    Langerhans' cell histiocytosis with multiple radiolucent lesions in the body of the mandible,report of a case

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    Introduction: Langerhans cell histiocytosis (LCH) refers to a group of rare reticuloendothelial system disorders and it occurs most often in young adults and children. A 57-year-old edentulous female patient who complained of dull pain in the posterior region of the mandible referred to the dental office, with a complaint of dull pain in the posterior region of the mandible. The lesion was diagnosed as LCH. Oral manifestations could be the first signs of Langerhans' cell histiocytosis. Therefore, the dentist must be aware of the oral symptoms so in order that the disease is not overlooked

    Prevalence and Pattern of Styloid Process Elongation and Calcification on Digital Panoramic Radiographs in an Iranian Population

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    Background and Aim: Considering the importance of the clinical significance of the elongated styloid process, this study aimed to assess the prevalence and pattern of calcification and elongation of the styloid process on digital panoramic radiographs of an Iranian population. Materials and Methods: This study was conducted on 500 digital panoramic radiographs of patients over 18 years old with visible styloid processes. The length of styloid processes was measured by software, and the length>30mm was considered as elongated. Prevalence and pattern of elongation and calcification were determined according to the classification proposed by Langlais. The associations of age, sex, and the jaw side of elongation was determined using generalized estimating equations with exchangeable matrix and binary logistic model. Results: Elongation of styloid process was observed in 177 (17.7%) of 1000 evaluated processes were elongated. The Type I pattern of elongation (n=80, 45%) and type A pattern of calcification (n=69, 39%) had the highest frequency. Although the prevalence of elongation seemed to be higher in males, the difference was not significant (P=0.11). No significant association was observed between the side of jaw and elongation (P=0.54). Elongation was more common in the 40-59-year-old group compared to <40-year-old group (P=0.014). Conclusion: The prevalence of elongated styloid process often considered as an anatomical variation and has been reported differently in the literature. Dentists should pay more attention to it during clinical examination especially in the case of pain in head and neck

    Diagnostic Accuracy of Charge-coupled Device Sensor and Photostimulable Phosphor Plate Receptor in the Detection of External Root Resorption In Vitro

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    Background and aims. Early diagnosis of external root resorption is important for accurate treatment. The purpose of this study was to compare the efficacy of a charge-coupled device (CCD) sensor and a photostimulable phosphor (PSP) plate receptor in the diagnosis of artificial external root resorption. Materials and methods. In this diagnostic in-vitro study, 40 maxillary incisors were mounted in a segment of dry bone and preliminary radiographs were obtained using CCD and PSP sensors. Artificial resorption cavities were produced on the middle-third in half of the samples and on the cervical-third in the other half on the buccal root surfaces. Radiographs were repeated and images were evaluated. Data were statistically analyzed using chi-square and diagnostic tests. Results. There were no significant differences between the two sensors in the sensitivity (p=0.08 and 0.06) and specificity (p=0.13) for the diagnosis of resorption in both root areas. The overall accuracy of CCD was higher than PSP sensor; how-ever, the difference was not statistically significance (p>0.05). Conclusion. CCD and PSP sensors chosen for the present study produced similar results in diagnosing simulated external root resorption

    Age Estimation from Pulp/Tooth Area Ratio Using Digital Panoramic Radiography

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    Background and Aim: To estimate the age in forensic identification, when none of the other identification methods are feasible, the teeth are used. The aim of the present study was to estimate the age from pulp/tooth area ratio (AR) by digital panoramic radiography in patients referred to a radiology clinic. Materials and Methods: In this diagnostic study, digital panoramic radiographs of 120 cases were assessed. The chronological age was calculated by subtracting the date of birth from the date of radiographs and the AR was calculated with "AutoCAD" software. Using the regression model, the age was estimated. In this study, the role of sex was also assessed. Results: The mean difference between the chronological and the estimated age was 0.11 years in male group. The correlation coefficient was -0.180 and the correlation between age and AR was not statistically significant (p= 0.169). The mean difference between the chronological and estimated age was 0.36 years in female group. Correlation coefficient was -0.336 and the correlation between age AR was significant (p= 0.004). Negative cor-relation indicates that AR decreases by aging. Conclusion: According to the results, AR cannot be used for age estimation alone but it can be used in combination with other indices for this purpose

    Central Odontogenic Fibroma of Mandible: A Case report

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    Background and Aims: Central odontogenic fibroma is a rare odontogenic neoplasm that originates from odontogenic ectomesenchyme. Most cases occur in the mandible and between the ages of 11 and 39 years. The neoplasm shows a definite female preponderance, with a ratio of 2.2:1 and has a very low recurrence rate. The aim of this article was to report a case of this rare lesion which was accidental found. Case Report: A 11-year-old female, during her orthodontic treatment and without any complain and any sign or symptoms, performed a panoramic image for assessing the permanent teeth buds. In the panoramic view a unilocular radiolucent lesion with well-defined and corticated borders in the right mandibular body region was evident. The lesion was treated with simple excision. Simple type of central odontogenic fibroma histopathologic features was observed in the microscopic view. Conclusion: Although the central odontogenic fibroma is a rare benign neoplasm, however, a careful evaluation of radiographic images is important for early detection of lesions because the patient may have no clinical symptoms such as swelling, pain and paresthesia

    The effects of anatomical location and distance from dental implants on the quality and quantity of metal artifacts in cone beam computed tomography scans: a cross-sectional study

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    Abstract Background Artifacts in cone beam computed tomography (CBCT) images can cause disruptions in diagnosis and treatment. Multiple factors influence the artifacts, including the quality and technology of devices, positions, patient-related factors, device settings, and bone density. Besides, anatomical area and distance from the implant affect the artifacts. This study aimed to investigate the effects of anatomical location and distance from the implant on the quality and quantity of artifacts. Methods A total of 200 CBCT images of patients with titanium implants and prostheses in the anterior and posterior regions of the maxilla and mandible were evaluated in this study. Four areas were assessed for each implant in three apical, middle, and cervical regions with distances of 3 mm, 4 mm, and 5 mm from the implant. Besides, the impact of adjacent implants on the artifacts was investigated. An ANOVA test with post hoc Bonferroni correction was used to analyze variable differences between subgroups. Results The differences were statistically significant, except for the difference between the posterior areas of the upper and lower jaws. A comparison of different areas revealed that most artifacts were related to the anterior maxilla, followed by anterior mandibular regions. The results of covariance analysis indicated that region and location had independent effects on the amount of artifacts. Conclusions Artifacts are more frequent in the anterior region compared to the posterior site. They are also more frequent in the maxilla than the mandible and cervical areas close to the implant than the middle and apical regions

    Comparison of the Absorbed Dose of Target Organs in Conventional and Digital Lateral Cephalometric Radiography

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    Background and Aim: Due to the widespread use of lateral cephalometric radiography especially in orthodontic therapy and orthognathic surgery, obtaining radiographs of high quality with the least amount of radiation exposure is of utmost importance. The aim of this study was to compare the absorbed dose of head and neck target organs in conventional and digital lateral cephalometric radiography .   Materials and Methods : In this experimental study, RANDO phantom was used for absorbed dose estimation in thyroid, parotid, pituitary and submandibular glands, bone marrow and ocular lens. The phantom was exposed 60 times: 30 times with CRANEX Tome, Soredex and 30 times with CRANEX D, Soredex with standard exposure settings. TLD (GR-200) dosimeters were used to measure organ doses. A total of 69 TLDs were used with 9 TLDs for background radiation. T-test was used for statistical analysis .   Results: The mean absorbed dose of target organs was 0.04±0.005 mSv for conventional and 0.01±0.002 mSv for digital technique. The difference in absorbed dose in all target organs except for the thyroid gland (P=0.08) between the two techniques of conventional and digital was statistically significant. (P=0.01 ).   Conclusion: Use of digital lateral cephalometric system causes a significant reduction in absorbed dose compared to the conventional film-screen syste
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