The effect of metal artifacts on the identification of vertical root fractures using different fields of view in cone-beam computed tomography

PURPOSE: The aim of this study was to investigate the effects of metal artifacts on the accurate diagnosis of root fractures using cone-beam computed tomography (CBCT) images with large and small/limited fields of view (FOVs). MATERIALS AND METHODS: Forty extracted molar and premolar teeth were collected. Access canals were made in all teeth using a rotary system. In half of the teeth, fractures were created by the application of mild pressure with a hammer. The teeth were then randomly put into a wax rim on an acryl base designed in the shape of a mandible. CBCT scans were obtained using a Newtom 5G system with FOVs of 18 cmx16 cm and 6 cmx6 cm. A metal pin was then placed into each tooth, and CBCT imaging was again performed using the same fields of view. All scans were evaluated by two oral and maxillofacial radiologists. The specificity, sensitivity, positive predictive value, negative predictive value, and likelihood ratios (positive and negative) were calculated. RESULTS: The maximum levels of sensitivity and specificity (100% and 100%, respectively) were observed in smallvolume CBCT scans of teeth without pins. The highest negative predictive value was found in the small-volume group without pins, whereas the positive predictive value was 100% in all groups except the large-volume group with pins. CONCLUSION: The specificity of CBCT decreased with the presence of a pin in the large-volume group, but not in the small-volume group.

A comparative study of cone-beam computed tomography and digital periapical radiography in detecting mandibular molars root perforations

PURPOSE: The aim of this in vitro study was to determine the sensitivity and specificity of cone-beam computed tomography (CBCT) and digital periapical radiography in the detection of mesial root perforations of mandibular molars. MATERIALS AND METHODS: In this in vitro study, 48 mandibular molars were divided into 4 groups. First, the mesial canals of all the 48 teeth were endodontically prepared. In 2 groups (24 teeth each), the roots were axially perforated in the mesiolingual canal 1-3 mm below the furcation region, penetrating the root surface ("root perforation"). Then, in one of these 2 groups, the mesial canals were filled with gutta-percha and AH26 sealer. Mesial canals in one of the other 2 groups without perforation (control groups) were filled with the same materials. The CBCT and periapical radiographs with 3 different angulations were evaluated by 2 oral and maxillofacial radiologists. The specificity and sensitivity of the two methods were calculated, and P<0.05 was considered significant. RESULTS: The sensitivity and specificity of CBCT scans in the detection of obturated root canal perforations were 79% and 96%, respectively, and in the case of three-angled periapical radiographs, they were 92% and 100%, respectively. In non-obturated root canals, the sensitivity and specificity of CBCT scans in perforation detection were 92% and 100%, respectively, and for three-angled periapical radiographs, they were 50% and 96%, respectively. CONCLUSION: For perforation detection in filled-root canals, periapical radiography with three different horizontal angulations would be trustworthy, but it is recommended that CBCT be used for perforation detection before obturating root canals.

Root-crown ratio in permanent dentition using panoramic radiography in a selected Iranian population

Statement of the Problem: Determining the crown-root ratio is crucial in many dental clinical decisions. There are no reliable data presented for Iranian population

Purpose: The aim of this study was to assess the root-crown ratio of permanent teeth with regards to the relationship of gender and jaw type using panoramic radiographs. The reliability of method was also assessed

Materials and Method: The crown and root lengths of teeth were measured by a digital caliper on panoramic radiographs of 185 individuals except for the third molars. A total of 1994 teeth was studied and 50.8% of the teeth belonged to males and 49.2% belonged to females. The modified Lind method was applied

Results: The highest mean root-crown ratios in both arches of both genders were obtained in the second premolars, followed by the first premolars and canines. In both genders, the lowest root-crown ratios were found in the maxillary central incisors. In male patients, the mean root-crown ratio was higher [p= 0.003] than that of females. Using Bland-Altman analysis, a non-significant difference of 0.006 [95% CI: -0.012-0.024] and 0.0002 [95% CI: -0.011-0.011] were found for intra-observer and inter-observer agreement, respectively

Conclusion: Assessment of the root-crown ratio in permanent dentition could be performed on panoramic radiographs with acceptable reproducibility in an Iranian Population. Considering observed differences, our findings suggest that for the accurate assessment, this ratio must be calculated for male and female patients and also for the upper and lower jaws, separately

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

Assessment of vertical root fracture using cone-beam computed tomography

PURPOSE: The aim of this study was to investigate the accuracy of cone-beam computed tomography (CBCT) in the diagnosis of vertical root fractures in a tooth with gutta-percha and prefabricated posts. MATERIALS AND METHODS: This study selected 96 extracted molar and premolar teeth of the mandible. These teeth were divided into six groups as follows: Groups A, B, and C consisted of teeth with vertical root fractures, and groups D, E, and F had teeth without vertical root fractures; groups A and D had teeth with gutta-percha and prefabricated posts; groups B and E had teeth with gutta-percha but without prefabricated posts, and groups C and F had teeth without gutta-percha or prefabricated posts. Then, the CBCT scans were obtained and examined by three oral and maxillofacial radiologists in order to determine the presence of vertical root fractures. The data were analyzed using IBM SPSS 20.0 (IBM Corp., Armonk, NY, USA). RESULTS: The kappa coefficient was 0.875+/-0.049. Groups A and D showed a sensitivity of 81% and a specificity of 100%; groups E and B, a sensitivity of 94% and a specificity of 100%; and groups C and F, a sensitivity of 88% and a specificity of 100%. CONCLUSION: The CBCT scans revealed a high accuracy in the diagnosis of vertical root fractures; the accuracy did not decrease in the presence of gutta-percha. The presence of prefabricated posts also had little effect on the accuracy of the system, which was, of course, not statistically significant.

A comparison between conventional and digital radiography in root canal working length determination.

Aim and Objectives: Obtaining a correct working length is necessary for successful root canal treatment. The aim of this study was to compare conventional and digital radiography in measuring root canal working length. Materials and Methods: In this in vitro study 20 mesio buccal canal from maxillary first molars with moderate and severe curvature and 20 canal form anterior teeth with mild curvature were chosen and their working length were measured with number 15 k file (Maillefer, DENTSPLY, Germany). Then for each canal five radiographies were taken, three conventional radiographies using three methods of processing: Manual, automatic, and monobath solution; in addition to two other digital radiographies using CCD and PSP receptors. Two independent observers measured working length in each technique. Finally, the mean of working length in each group was compared with real working length using a paired T-test. Also a one-way ANOVA test was used for comparing the two groups. The level of statistical significance was P < 0.05. Results: The results have shown that there was a high interobserver agreement on the measurements of the working length in conventional and digital radiography (P≤0.001). Also there was no significant difference between conventional and digital radiography in measuring working length (P > 0.05). Conclusion: Therefore it was concluded that the accuracy of digital radiography is comparable with conventional radiography in measuring working length, so considering the advantages of the digital radiography, it can be used for working length determination.