Association between gubernacular canals characteristics and teeth eruption status: a cone-beam computed tomography study.

Background: There have been few studies that have evaluated the imaging characteristics of the gubernacular canal. Additionally, it is important to understand the role of this structure and its relationship with tooth erupt. Therefore, the objective of this study was to investigate the association between gubernacular canal features and teeth eruption status on cone-beam computed tomography (CBCT) images. Material and Methods: In this cross-sectional study, 150 CBCT images were obtained from patients referred to a maxillofacial radiology clinic in Babol, northern Iran, in 2021. Eruption status (normal, delayed, and impacted) and the presence of the gubernacular canal were recorded. If the gubernacular canal was detected, its opening site in the alveolar crest (buccal, lingual, and central) and its attachment site to the dental follicle (usual, unusual) were further assessed. Results: Gubernacular canal was observed in 133 (88.7%) of the total 150 CBCT images. Also, 41 cases (27.3%) had impacted teeth. The detection rate of the gubernacular canal in the normal, delayed, and impacted eruption of teeth was 92.1% (n=93), 75.0% (n=6), and 82.9% (n=34), respectively (p=0.135). Opening the gubernacular canal in the alveolar crest was not associated with teeth eruption status. Also, unusual attachment sites of the gubernacular canal to dental follicles were mostly seen in abnormal eruptions. Conclusions: According to the findings, observing the presence of the gubernacular canal on CBCT may not help anticipate teeth eruption problems. Key words:Gubernacular canal, Cone-beam computed tomography, Tooth eruption.

Genotoxic and Cytotoxic Effects of Cone Beam Computed Tomography and Multidetector Computed Tomography on Exfoliated Buccal Epithelial Cells.

Background: Cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) are frequently used in dental and maxillofacial problems. This study aimed to assess the genotoxicity and cytotoxicity effects of CBCT and MDCT radiographies on exfoliated buccal epithelial cells during dental examinations. Methods: This prospective experimental study was conducted at Babol University of Medical Sciences (Babol, Iran) from March 2021 to April 2021. Buccal mucosa smears were collected bilaterally pre-exposure and 12 days after CBCT or MDCT examinations. To compare the frequency of micronuclei and other cytotoxic cellular changes such as pyknosis, karyolysis, and karyorrhexis, the paired sample t test and Wilcoxon test were used. In addition, independent sample t test, Mann-Whitney, and Chi square tests were used to investigate the differences between the imaging methods and between men and women. All statistical analyses were performed using the SPSS software, and P≤0.05 was considered statistically significant. Results: The current study included 60 adult patients (30 patients in each group), ranging in age from 21 to 50 years. The micronuclei and the other cytotoxic cellular changes increased significantly after CBCT and MDCT radiographic examinations on the 12th day compared to the pre-exposure results (P<0.001). MDCT had statistically higher cytotoxic and genotoxic effects than CBCT (9.4%, 23.1%, and 40% higher values in micronucleus frequency, the mean frequency of micronuclei, and other cytotoxic changes, respectively). There were no significant differences between men and women in the two examination methods (P=0.46 and P=0.49, respectively). Conclusion: Dental examinations with CBCT and MDCT can increase cytotoxicity and chromosomal damage in both men and women. Due to its lower radiation toxicities, CBCT can be recommended as an alternative to MDCT for dental examinations.

Comparison of accuracy cone-beam computed tomography and digital bitewing radiography for detection of recurrent caries under various restorative materials: in vitro study.

OBJECTIVE: The aim of this study was to compare and evaluate diagnostic accuracy of two different CBCT scan modes and digital bitewing radiography for detection of recurrent caries under five different restorative materials, and determine the relationship between the types of restorative materials. MATERIALS AND METHODS: In this in vitro study, 200 caries-free upper and lower premolars and molars were selected. A standard deep Class II cavities was created in the middle of the mesial surface of all teeth. In 100 teeth of the experimental and control groups, secondary caries was artificially demineralized. All teeth were filled with five types of restorative material including two types of conventional composite resins, flow composite resin, glass ionomer and amalgam. The teeth were imaged with high resolution (HIRes) and standard CBCT scan modes and digital bitewing. The AUC, sensitivity, specificity and areas under the ROC curve were calculated and verified through SPSS. RESULTS: CBCT technique was the best option in diagnosing recurrent caries. The diagnostic accuracy and specificity of HIRes CBCT scan mode was significantly higher than standard mode (P = 0.031) and bitewing (P = 0.029) for detection of recurrent caries, especially under composite group. There were no significant differences in accuracy value of bitewing and standard CBCT scan mode. CONCLUSION: CBCT showed higher accuracy and specificity on the detection of recurrent caries which was more accurate than bitewing radiography. The HIRes CBCT scan mode achieved the highest accuracy and performed the best in recurrent caries detection.

Genotoxicity and cytotoxicity effects of x-rays on the oral mucosa epithelium at different fields of view: A cone beam computed tomography technique.

Background: Cone beam computed tomography (CBCT) is considered a common examination for dentistry problems. Cellular biology can be affected by exposure to ionizing radiations procedures. In this study, we aimed to assess the genotoxicity and cytotoxicity effects of CBCT dental examinations at two different fields of view (FOVs) in exfoliated buccal epithelial cells. Methods: Sixty healthy adults participated in the current study. They were divided into two identical groups; CBCT with FOV of 6*6 cm2 and 8*11 cm2. Exfoliated oral mucosa cells were prepared immediately before and after 10-12 days of CBCT exposure. The cytological smears were stained with the Papanicolaou technique. The amounts of micronuclei and other cytotoxicity cellular changes (Pyknosis, Karyolysis, and Karyorrhexis) were evaluated. The variables of the parameters before and after CBCT examination in the two investigated FOVs were performed using Wilcoxon test and paired-samples t-test in SPSS software. Results: The micronuclei and other cytotoxic changes parameters before and after CBCT exposure for both FOVs (6*6 and 8*11 cm2) increased significantly (p<0.001). Furthermore, a significant difference (p<0.05) was observed between the investigated parameters at the two FOVs. Notably, the FOV of 8*11 cm2 had more side effects than that of 6*6 cm2. There were no statistically significant among males and females for both FOVs. Conclusion: CBCT examinations of dental disorders would increase the risks of inducing genetic damage. The cytotoxicity and chromosomal damage were considered in males and females in both investigated FOVs (6*6 and 8*11 cm2). In this regard, the use of CBCT must be following the ALARA principle.

Focal Cemento Osseous Dysplasia: A Case Report.

Focal cemento osseous dysplasia (FCOD) is a subgroup of benign fibro osseous lesions, which occur in a single site of tooth-bearing areas of jaws. It is usually asymptomatic and noticed accidentally through routine radiological exams. There is often no need for treatment of such lesions. This case was a 28-year-old male patient with a mixed radiolucent-radiopaque lesion in posterior part of his mandible. Based on radiographic examination, cemento ossifying fibroma (COF) was the first differential diagnosis. After the surgical removal of the lesion, histopathologic evaluation was made and the case was diagnosed as FCOD. Fortunately, after a few months of operation, there was no complication and complete bone formation was occurred.

Can the Follicle-Crown Ratio of the Impacted Third Molars be a Reliable Indicator of Pathologic Problem?

STATEMENT OF THE PROBLEM: The presence of impacted third molars in the jaws is a common finding in the routine dental examination of patients. Concerning the odontogenic components of the dental follicle, it can be the origin of different types of odontogenic cysts and tumors. PURPOSE: The aim of this study was to find feasible radiographic criteria to help differentiate between normal and pathological dental follicles. MATERIALS AND METHOD: 134 asymptomatic impacted third molars were recruited in this study. Then, based on the radiographic measurements, the ratio between the diameter of the dental follicle and the mesiodistal width of the tooth crown was calculated. After surgical removal of impacted third molars, the related dental follicles were evaluated histopathologically. Statistical analyses were performed by adopting chi-square test, t-test, receiver oprating characteristic (ROC) curve, and logistic regression using SPSS-19 software. RESULTS: The mean ratio of the dental follicle's diameter to the mesiodistal width, in the normal and cystic follicle group was 1.18 ± 0.07 and 1.18 ± 0.08, respectively. There was no statistically significant difference between this ratio and the histopathological evaluation. Based on the logistic regression analysis, only the age >20 years and inflammation had predictive value in identifying cystic changes in dental follicle. CONCLUSION: According to the findings of the current study, the ratio of dental follicle diameter to the mesiodistal width of the teeth cannot not be employed as a diagnostic index to differentiate between normal and pathological dental follicle.

Endodontic treatment of fused teeth with talon cusp.

Tooth anomalies are rare phenomena that may be reported by patients as chief complaints or may be discovered by dentists in the oral examination. In a few cases, rare anomalies are found together in one mouth. Decision to treat such anomalies depends on whether or not they interfere with function and esthetics and also the patient's preference. In the present case, a 19-year-old male presented with two right maxillary fused central and lateral incisors and a geminated left maxillary central incisor. A talon-like projection was found at the junction site of the fused teeth. His chief complaint was sensitivity to cold at the site of the giant fused tooth. This report describes the process of diagnosis and treatment of the two anomalies according to patient preference and needs.