Endodontic applications of cone beam computed tomography: case series and literature review

Frequency of middle mesial canal in mandibular first molars and its association with various anatomic variables

This study aimed to determine the frequency of the middle mesial canal in the mandibular first molars and its association with various anatomical features. Two experienced endodontists evaluated 149 CBCT images, containing n = 298 mandibular first molars and n = 298 mandibular second molars. Binary logistic regression was used to explore the relationship between the presence of middle mesial canal and other independent variables. The middle mesial canal was found in 7.7% (n = 23) of mandibular first molars and 11.4% of which exhibited adjacent C-shaped mandibular second molars. The presence of an adjacent C-shaped mandibular second molar was associated with a 3 times increased likelihood of finding a middle mesial canal (P = 0.048, OR: 3.108) in mandibular first molars. The middle mesial canal is an uncommon finding with a rare occurrence of bilateral presence in mandibular molars; however, an adjacent C-molar is an important predictor of middle mesial canal presence.

The morphology of the pulp chamber floor of permanent mandibular first and second molars in an Indian subpopulation-a descriptive cross-sectional study employing Pawar and Singh classification

Background

Mandibular molars are multi-rooted teeth with a complex and strenuous root canal anatomy. Because there is relatively negligible literature describing the pulp chamber floor anatomy, predicting the exact anatomical layout and its variations is daunting. A thorough comprehension and knowledge of the same is required for efficacious endodontic treatment consequence. The purpose of this study was to characterise and ascertain the pulp chamber floor anatomy of permanent mandibular first (ManFMs) and second (ManSMs) molars in an Indian population.

Methods

On 2,134 extracted human mandibular first (ManFMs = 1,067) and second molars (ManSMs = 1,067), a descriptive cross-sectional investigation was executed. Cleaning and removal of hard and soft tissue debris were performed, followed by flattening the anatomical crown until the pupal architecture was uncovered. A stereomicroscope with a magnification of 4.5 magnification was used to investigate the pulpal anatomy. Statistical analysis was carried out using chi square test, with 95% confidence intervals and a p value of 0.05 considered statistically significant.

Results

The majority of the ManFMs showed presence of three canal orifices in 57.73%, followed by four orifices 31.31%, five orifices 8.81%, and six orifices 2.15%. For ManSMs, majorly three orifices were found in 39.83% specimens, followed by two orifices in 37.39%, four orifices in 16.31%, and single root canal orifice was observed in 6.47%. The mesio-buccal, mesio-lingual, disto-buccal, disto-lingual canal orifices exhibited round and oval shapes in both ManFMs and ManSMs. The shape was predominantly oval with a single distal canal orifice (84.25% ManFMs and 74.16% ManSMs). In ManSMs, among the single root canal orifice, 66.66% were round in shape and 33.34% were C-shaped. In ManSMs with two root canal orifices, mesially 79.44% exhibited oval and 20.56% round shape. Distally, 74.16% were oval and 25.84% were round. The shapes of the access cavities for ManFMs were rectangular in 46.67% and triangular in 53.33%. For the ManSMs, the access cavities were triangular in 39.83%, rectangular in 16.31% and non-classified (others) in 43.86% of specimen. In both ManFMs and ManSMs, the pulp chamber floor morphology was predominately Y shaped (57.73% and 39.83%) according to the Pawar and Singh classification© of pulp chamber floor anatomy.

Conclusion

Our study indicated that the orifices on the pulp chamber floor are arranged in a typical manner, supporting the proposed categorization. Furthermore, description of the anatomical patterns of the pulp chamber guides the clinicians in chair-side treatment decisions.

Prevalence of dens invaginatus and its association with periapical lesions in a Western Indian population-a study using cone-beam computed tomography

OBJECTIVES

This study aimed to assess the prevalence of dens invaginatus (DI) and its association with periapical lesions (PLs) in a Western Indian population by means of cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

CBCT volumes of 5201 subjects were evaluated. Associations among gender, tooth type, DI type (Oehler's classification), and presence of PL were investigated. PL was codified using Estrela's Cone Beam Computed Tomography Periapical Index (CBCTPAI). Chi-square tests and descriptive statistics were used at p = 0.05.

RESULTS

Overall, 7048 CBCTs were assessed, containing 19,798 maxillary and mandibular anteriors, of which 77 maxillary teeth demonstrated DI (0.39% of all anteriors). Of all 5201 subjects, 57 had DI (1.1%). Bilateral DI was more common in females than in males (p = 0.046). DI type distribution was as follows: type I (22.1%), type II (61.03%), type IIIa (10.4%), and type IIIb (6.5%), which was significantly different (p < 0.001). Maxillary lateral incisors were the most associated with PL (p < 0.001). Type I was frequently associated with CBCTPAI scores 1 and 2 (absence of PL), whereas types II, IIIa, and IIIb were associated with CBCTPAI scores 3, 4, and 5 (presence of PL).

CONCLUSIONS

A prevalence of 1.1% identifies DI as a common developmental tooth anomaly in a Western Indian subpopulation. The percentage of maxillary anteriors affected by DI and associated PLs should be considered before diagnosis and treatment planning.

CLINICAL RELEVANCE

Knowledge about the prevalence of DI and its subtypes, and their association with/without periapical pathosis may aid clinicians in treatment planning and execution to improve patient outcomes.

The Accuracy of CBCT in the Detection of Dens Invaginatus in a Tunisian Population

Objective

To assess the prevalence and characteristics and to classify the type of dens invaginatus (DI), in anterior teeth, basing on 200 Tunisian patients' cone-beam computed tomography. Material and Methods. A retrospective study was performed using CBCT images of 200 Tunisian patients. Maxillary and mandibular anterior teeth were evaluated for the presence and characteristics of dens invaginatus. Results were reported as frequencies, means ± SD. Statistical evaluation of the presence of DI related to gender was performed by the Pearson chi-square test.

Results

Dens invaginatus was observed in 42 out of 4945 examined teeth, with a prevalence of 0.85%.The anomaly affected especially maxillary lateral incisors (p ≤ 0.001). DI location was unilateral in 36% and bilateral in 64%. Type II DI was the most commonly observed (47.61%), followed by type I (30.95%) and type III (21.42%). Apical periodontitis (AP) was mostly seen in type III DI, with a periapical index (PAI) varying from 3″ to 5 E″.The maxillary lateral incisors seem to be the most affected anterior teeth. The symmetric occurrence of DI was observed with a statistically significant difference (p ≤ 0.001).

Conclusion

Within the limits related to the present study, DI detected by CBCT is a rare anomaly that could be associated with AP. Maxillary anterior teeth should be bilaterally examined for DI in the absence of clinical symptoms.

Density estimation based on the Hounsfield unit value of cone beam computed tomography imaging of the jawbone system

The aim of this study is to investigate the estimation of density from the Hounsfield unit of cone beam computed tomography data in dental imaging, especially for dental implant application. A jaw phantom with various known densities of anatomical parts (e.g. soft tissue, cortical bone, trabecular bone, tooth enamel, tooth dentin, sinus cavity, spinal cord and spinal disc) has been used to test the accuracy of the Hounsfield unit of cone beam computed tomography in estimating the mechanical density (true density). The Hounsfield unit of cone beam computed tomography data was evaluated via the MIMICS software using both two-dimensional and three-dimensional methods, and the results showed correlation with the true density of the object. In addition, the results revealed that the Hounsfield unit of cone beam computed tomography and bone density had a logarithmic relation, rather than a linear one. To this end, the correlation coefficient of logarithmic correlation (R2 = 0.95) is higher than the linear one (R2 = 0.77).

Effect of Voxel Size on Detection of External Root Resorption Defects Using Cone Beam Computed Tomography

BACKGROUND

Selecting a voxel size that yields minimal radiation dose with no significant compromise of the diagnostic accuracy of cone beam computed tomography (CBCT) is particularly important.

OBJECTIVES

This study aimed to assess the effect of voxel size on detection accuracy of simulated external root resorption defects using NewTom CBCT system.

MATERIALS AND METHODS

In this diagnostic study, the roots of 90 extracted human central incisors were hypothetically divided into cervical, middle, and apical thirds. Variable-size defects were prepared in the buccal and lingual surfaces of the roots and CBCT scans were obtained with four different voxel sizes (150, 200, 250, and 300). Presence or absence of defects on CBCT scans was determined by three radiologists and the results were compared with the gold standard (actual size and depth of defects). Sensitivity and specificity values were calculated and reported for different groups.

RESULTS

In the lingual surfaces, the highest specificity and sensitivity belonged to 300µm voxel size (92.9%), and 200 and 250µm voxel sizes (both 97.4%) in the cervical third, respectively. In the middle third, the highest specificity and sensitivity belonged to 250 and 200µm voxel sizes (84.6% and 100%, respectively). In the apical third, the highest specificity and sensitivity belonged to 300 µm voxel size (100% and 97.9%, respectively). In the buccal surfaces, the highest specificity and sensitivity belonged to 150 (75.0%), 300 and 250 µm voxel sizes (100%) and the minimum values belonged to 200 µm voxel size (60% and 97.3%) in the cervical third. In the apical third, the highest specificity and sensitivity were noted in 300 µm voxel size (100% and 97.6%, respectively) and the minimum values were seen in 200 and 150 µm voxel sizes (93.8%, 90.5%, respectively). In the middle third, 300, 250 and 200 µm voxel sizes yielded the highest specificity (88.9%), while 150 µm voxel size yielded the highest sensitivity (98.8%).

CONCLUSION

Considering the similar diagnostic efficacy of all voxel sizes, 300 µm voxel size can be used with adequate efficacy for detection of external root resorption defects with minimal patient radiation dose and the shortest scanning time.