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Purpose The primary aim of this study was to evaluate the buccal bone concavity position and depth in the anterior maxilla. The accuracy of cone beam computed tomography (CBCT) to measure the buccal bone concavity was also investigated. Material and methods Eleven fresh cadaver heads were used in this study. CBCT images were first acquired, on which the location and depth of the buccal bone concavity were measured in maxillary incisors and canines. After full-thickness mucoperiosteal flap reflection, the corresponding measurements were made directly on cadavers. The accuracy and correlations between direct and image-derived measurements were analyzed statistically. Results A total of 53 sites were measured. The mean depths were 2.88 ± 1.37 mm and 2.40 ± 1.29 mm (with direct and CBCT measurement, respectively). The deepest concavities were found in the lateral incisors sites (3.15 ± 1.32 mm). There was a statistically significant underestimation of the depth of concavity (0.2 to 0.6 mm) by CBCT. Nevertheless, there is a high statistical correlation (r = 0.8) between the direct and CBCT measurements. Conclusions Within the limitations of this study, it can be concluded that buccal bone concavity is the most prominent at the lateral incisor sites. The CBCT readings were highly correlated but underestimated to the direct measurements.

Background/purpose: Inadequacy to locate the second mesiobuccal canal (MB2) canal leads to the highest probability of endodontic failure in permanent maxillary first molars (PMFMs) and still remains a constant challenge for many clinicians. The aim of this study was to characterize the geometrical features between MB2 and other orifices of examined PMFMs using cone-beam computed tomography images. Materials and methods: A total of 108 teeth qualified in the cone-beam computed tomography image archives were enrolled in the present study. The intersecting point (T) was determined as the perpendicular line (h, altitude of triangle) projected from the vertex of the MB2 canal orifice to mesiobuccal canal orifice-palatal canal orifice line (MB1-P). We measured the geometric features of PMFMs with the MB2 canal, including the interorifice distances, area, altitude, and the ratio between the canal orifices. Results: The average interorifice distance was found to be 1.91±0.59 mm for MB1-MB2, 5.73±0.66 mm for MB1-P, and 4.11±0.79 mm for MB2-P, with significant gender difference for MB1-MB2 distance. For the MB1-T distance, a significant difference was found between genders (P=0.02), with males averaging 1.78±0.07 mm, and females 1.48±0.11 mm. For the MB1-P distance, the majorities of both genders were found in the 20–40% cut-off. A portion of the males exhibited a tendency towards the 40–80% cut-off, while females shifted in the reverse direction towards the 0–20% cut-off. Conclusion: In clinical scenarios, these anatomical characteristics of the root canals system could be beneficial to locating the MB2 canal. Keywords: cone-beam computed tomography, maxillary molar, morphology, root canal

Introduction The purpose of this study was to examine the frequency and bilateral consistency of distolingual roots (DLRs) in permanent mandibular first molars (PMFMs) and root canal configurations in PMFPs (permanent mandibular first premolars) and to determine the correlation between the root canal configurations of PMFPs with the appearance of DLRs in PMFMs. Methods A total of 932 cone-beam computed tomographic images of PMFMs and PMFPs were collected from 233 patients. The frequency and bilateral consistency of DLRs in PMFMs along with root canal configurations (root number and canal number) of PMFPs were recorded and evaluated ipsilaterally and contralaterally. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMFPs with the appearance of DLRs in PMFMs. Results The prevalence of PMFMs with DLRs was 24.7%, and the incidence of complicated root canal configurations of PMFPs was 26.6%. The incidence of complicated root canal configurations of PMFPs was 19.6% in the non-DLR group, 37.2% in the unilateral DLR group, and 44.7% in the bilateral DLR group. After adjusting for categoric variables including sex, age, and side, the odds ratios for the frequency of complicated root canal configurations of PMFPs in the unilateral DLR and bilateral DLR groups compared with the non-DLR group were 2.472 (95% confidence interval, 1.434–4.263; P = .001) and 3.392 (95% confidence interval, 1.976–5.823; P Conclusions An increasing and corresponding trend between the presence of DLRs in PMFMs and complicated root canal configurations in PMFPs was noted in Taiwanese individuals. These results suggest that the clinicians should familiarize themselves with the anatomic variants of PMFMs and PMFPs before endodontic treatment.

The aim of this study was to determine the prevalence of C-shaped canal configurations (CSs) and radicular grooves (RGs) in permanent mandibular first premolars (MPs) and to investigate the relevance of such complexities with the presence of distolingual roots (DLRs) in permanent mandibular first molars (MMs).A total of 800 pairs of MPs and MMs were investigated using a cone-beam computed tomographic system (NewTom 5G; QR srl, Verona, Italy). The frequency and symmetry of DLRs in MMs along with the occurrence of RGs and CSs in examined MPs were evaluated. Multivariable logistic regression analysis was applied to examine the correlation between the CSs of MPs with the appearance of DLRs in MMs.In the examined teeth, 23.0% of MMs had a DLR, whereas 16.6% of MPs had RGs and 12.5% of MPs had C-shaped canals. Although the most common canal configuration in MPs is the single canal (74.1%), the other 25.9% still possess complicated root canals. Of these MPs that have different canal configurations, 54.6% had 2 canals, whereas 44.4% had CSs. Specifically, the CS showed a high prevalence of C3 morphologies at 98.9% followed by C1 at 1.1%. A corresponding and increasing frequency was noted in CSs and RGs of MPs and MMs with DLRs (P .001). After adjusting for related categoric variables, the adjusted odds ratios for CSs of MPs in the bilateral DLR group compared with the non-DLR group was 3.294 (P .001).This study showed an increased appearance of CSs in MPs when DLRs were present in MMs in the Taiwanese population.

The aim of this study was to assess the prevalence of complicated root canals in permanent mandibular central incisors (PMCIs) and its correlation with the presence of a distolingual root (DLR) in permanent mandibular first molars (PMFMs) using cone-beam computed tomographic imaging in a Taiwanese population.A total of 400 patients (800 pairs of PMCIs and PMFMs) were qualified for further analysis. The prevalence of DLRs in PMFMs along with root canal configurations of PMCIs were assessed at subject and tooth levels. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMCIs with the existence of DLRs in PMFMs.The prevalence of PMFMs with DLRs and complicated root canal configurations in PMCIs was 23.0% and 15.6%, respectively. A significant difference in age (50 years vs ≥50 years) was found for complicated root canal configurations in PMCIs. The most prevalent root canal system in PMCIs was Vertucci type I (84.4%) followed by type III (13.5%). A positive correlation between the presence of DLRs in PMFMs and complicated root canal configurations in PMCIs was noted. After adjusting for categoric variables including sex, age, and side, the odds ratios for the occurrence of complicated root canal configurations of PMCIs in the unilateral DLR group and the bilateral DLR group compared with the non-DLR group were 2.13 and 2.53, respectively.The concurrent appearance of DLRs in PMFMs and complicated root canal morphology in PMCIs is prominent in Taiwanese individuals.

Introduction The aim of this study was to assess the root canal configurations in permanent mandibular lateral incisors (PMLIs) and the correlation between the root canal configurations of PMLIs with the appearance of a distolingual root (DLR) in permanent mandibular first molars (PMFMs) using cone-beam computed tomographic (CBCT) imaging. Methods A total of 1200 CBCT images (300 patients) of PMFMs and PMLIs were investigated. The frequency and distribution of DLRs in PMFMs along with root canal configurations of PMLIs were assessed ipsilaterally and contralaterally. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMLIs with the appearance of a DLR in PMFMs. Results The prevalence of PMFMs with a DLR was 24.3%, and the incidence of complicated root canal configurations in PMLIs was 25.0%. The most prevalent root canal systems of PMLIs were Vertucci types I (75%) and III (23.0%). The incidence of complicated root canal configurations in PMLIs was 19.5% in the non-DLR group (ie, no DLR was found on either side of the PMFMs), 33.3% in the unilateral DLR (Uni-DLR) group (ie, a DLR was found in 1 of the PMFMs [the left or right side] and a DLR was not found on the other PMFM), and 39.8% in the bilateral DLR (Bil-DLR) group (ie, a DLR was found in both the right and left PMFMs). After adjusting for categoric variables including sex, age, and side, the odds ratios for the frequency of complicated root canal configurations of PMLIs in the Uni-DLR and Bil-DLR groups compared with the non-DLR group were 2.12 (P = .003) and 2.707 (P Conclusions The simultaneous appearance of DLRs in PMFMs and complicated root canal configurations in PMLIs is prominent in Taiwanese individuals. Clinicians should be aware of the correlation between the anatomic variants of PMFMs and PMLIs, which are important before endodontic treatment.

Purpose Facial crestal bone level and dimension determine function and esthetics of dentition and dental implants. We have previously demonstrated that ultrasound can identify bony and soft tissue structures in the oral cavity. The aim of this study is to evaluate the accuracy of using ultrasound to measure facial crestal bone level and thickness. Materials and methods A commercially available medical ultrasound scanner, paired with a 14 MHz imaging probe was used to scan dental and periodontal tissues at the mid-facial site of each tooth on 6 fresh cadavers. The alveolar crest level in relation to the cemento-enamel junction and its thickness on ultrasound images were measured and compared to those on cone-beam computed tomography (CBCT) scans and/or direct measurements on a total of 144 teeth. Results The mean crestal bone level measured by means of ultrasound, CBCT and direct measures was 2.66 ± 0.86 mm, 2.51 ± 0.82 mm, and 2.71 ± 1.04 mm, respectively. The mean crestal bone thickness was 0.71 ± 0.44 mm and 0.74 ± 0.34 mm, measured by means of ultrasound and CBCT, respectively. The correlations of the ultrasound readings to the other two methods were between 0.78 and 0.88. The mean absolute differences in crestal bone height and thickness between ultrasound and CBCT were 0.09 mm (-1.20 to 1.00 mm, p = 0.06) and 0.03 mm (-0.48 to 0.54 mm, p = 0.03), respectively. Conclusion Ultrasound was as accurate in determining alveolar bone level and its thickness as CBCT and direct measurements. Clinical trials will be required to further validate this non-ionizing and non-invasive method for determining facial crestal bone position and dimension.