Search

Objectives: The abutments produced with circular symmetry failed to accurately replicate the natural teeth's cervical shapes. The purpose of this study was to measure cervical cross‐sections of maxillary anterior teeth using cone beam computed tomography (CBCT) images to design anatomic healing abutments. Materials and Methods: CBCT data of 61 patients were analyzed using Ez3D Plus software. Measurements were taken at the cemento‐enamel junction (CEJ) and 1 mm coronal to CEJ for maxillary central incisors, lateral incisors, and canines. Various parameters, including area, perimeter, and eight line segments in the distal (a), disto‐palatal (b), palatal (c), mesio‐palatal (d), mesial (e), mesio‐labial (f), labial (g), and disto‐labial (h) directions, were used to describe dental neck contours. The ratios (f/b and h/d) were analyzed, and differences based on sex and dental arch morphology were explored. Results: Significant differences were found in area and perimeter between males and females, but not in f/b and h/d ratios. Differences in the f/b ratio were observed among dental arch morphologies for maxillary central incisors, lateral incisors, and canines. Conclusions: CBCT measurements of cervical cross‐sections provide more accurate data for designing anatomic healing abutments. The fabrication of anatomical healing abutments needs to consider the influence of gender on cervical size and to explore the potential effect of arch shape on cervical morphology. Clinical Significance: The novel method provides detailed measurements for the description of dental cervical contours for patients with bilateral homonymous teeth missing. The measurements of this study could be utilized to design more accurate anatomic healing abutments to create desired morphology of peri‐implant soft tissue. [ABSTRACT FROM AUTHOR]

This study quantified the exposure frequency and established the local diagnostic reference levels (DRLs) for the most common computed tomography (CT) examinations. A combined method census and sampling survey was used to quantify both frequency and radiation dose of CT examinations. Data were acquired through Picture Archiving and Communication System (PACS) or Radiology Information System (RIS). The annual frequency of CT examinations was 239.8 per 1000 inhabitants. The P 75 of volume CT dose index (CTDIvol) to adult patients from CT scanning for head, chest, abdomen and lumbar spine examinations were 63.0, 12.4, 20.0 and 24.0 mGy, respectively. The P 75 of dose-length product were 858.6, 416.0, 620.7 and 559.2 mGy·cm, respectively. This dose audit of CT practice can act as a starting point for establishing Huaian local DRLs and could be a reference for dose optimisation in China. This study compared DRLs in different countries and analysed some reasons for the rapid growth of CT examination frequency in Huaian. [ABSTRACT FROM AUTHOR]

Apical periodontitis (AP) is one of the most prevalent disorders in dentistry. However, it can be underdiagnosed in asymptomatic patients. In addition, the perioperative evaluation of 3-dimensional (3D) lesion volume is of great clinical relevance, but the required slice-by-slice manual delineation method is time- and labor-intensive. Here, for quickly and accurately detecting and segmenting periapical lesions (PALs) associated with AP on cone beam computed tomography (CBCT) images, we proposed and geographically validated a novel 3D deep convolutional neural network algorithm, named PAL-Net. On the internal 5-fold cross-validation set, our PAL-Net achieved an area under the receiver operating characteristic curve (AUC) of 0.98. The algorithm also improved the diagnostic performance of dentists with varying levels of experience, as evidenced by their enhanced average AUC values (junior dentists: 0.89–0.94; senior dentists: 0.91–0.93), and significantly reduced the diagnostic time (junior dentists: 69.3 min faster; senior dentists: 32.4 min faster). Moreover, our PAL-Net achieved an average Dice similarity coefficient over 0.87 (0.85–0.88), which is superior or comparable to that of other existing state-of-the-art PAL segmentation algorithms. Furthermore, we validated the generalizability of the PAL-Net system using multiple external data sets from Central, East, and North China, showing that our PAL-Net has strong robustness. Our PAL-Net can help improve the diagnostic performance and speed of dentists working from CBCT images, provide clinically relevant volume information to dentists, and can potentially be applied in dental clinics, especially without expert-level dentists or radiologists. [ABSTRACT FROM AUTHOR]

Copyright of West China Journal of Stomatology is the property of Sichuan University, West China College of Stomatology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this study was to evaluate the maxillary molar root canal morphology in individuals from the Shandong province, China, using cone-beam computed tomography (CBCT) and classify it based on Ahmed et al. (2017) classification system to obtain a reference for clinical diagnosis and treatment. From December 2020 to June 2021, we screened CBCT data of 1,619 patients at the Jinan Stomatological Hospital who had been indicated for CBCT because of various oral abnormalities. The root and root canal morphologies of all teeth were statistically analyzed, and the root canal morphology was classified based on Ahmed et al. (2017) classification system. In the maxillary molars, three roots were the most common, accounting for 99.24 % and 74.61 % of all maxillary first and second molars, respectively. Two roots were the second most common, accounting for 0.66 % and 17.29 % of all maxillary first and second molars, respectively. Root morphology variation, e.g., fusion or furcation defect, was present in 22 (0.76 %) maxillary first molars and 765 (25.39 %) maxillary second molars, with the most common being mesiobuccal and distobuccal root fusion. Detection rates of a second mesiobuccal canal (MB2) in the maxillary first and second molars were 48.5 % and 26.5 %, respectively. Among age groups, the frequency of MB2 was the highest in the 15-24-year-old group and lowest in the 55-64-year-old group. Bilateral MB2 root canals were present in 64.8 % and 48.4 % of the maxillary first and second molars, respectively. Men and women accounted for 60.6 % and 67.8 % of the maxillary first molars, respectively, and 51.7 % and 45.6 % of the maxillary second molars, respectively. According to Ahmed et al. (2017) classification of root canal morphology, 18 and 22 root canal configurations were found in 1,453 right maxillary first molars and 1,444 left maxillary first molars, respectively. The right maxillary first molars showed three two-rooted, 14 three-rooted, and one four-rooted type. The left maxillary first molars showed two one-rooted, six two-rooted, and 14 three-rooted types. According to Ahmed et al. (2017) classification of root canal morphology, 43 and 45 root canal configurations were found in 1,507 right maxillary second molars and 1,506 left maxillary second molars, respectively. The right maxillary second molars showed 17 one-rooted, 16 tworooted, eight three-rooted, and two four-rooted types. The left maxillary second molars showed 19 one-rooted, 13 two-rooted, 12 threerooted, and one four-rooted type. This study showed that the maxillary molar root canal morphology is diverse in the Shandong province. Ahmed et al. (2017) classification system provides a clear description of the root canal morphology. CBCT can be used to study complex root and root canal morphologies. [ABSTRACT FROM AUTHOR]

Objectives: Morphological study is a common approach in the field of anterior disc displacement (ADD) pathology; however, analysis based on three-dimensional reconstructive imaging has not been investigated. This study investigated the association between ADD and the status of the mandibular condyle and articular fossa. Methods: Thirty-four patients were divided into three groups: normal articular disc position (NADP), anterior disc displacement with reduction (ADDwR), and anterior disc displacement without reduction (ADDwoR). Multiple grouped comparisons of three different disc statuses were performed by Kruskal–Wallis H test and variance analysis respectively. Receiver-operating characteristic curve was plotted to assess the diagnostic efficacy of the morphological parameters. Multivariate logistic regression analysis was used to investigate the interfering factors of ADD. Results: The condylar volume (CV) and condylar superficial area (CSA) in the NADP, ADDwR, and ADDwoR groups exhibited obvious changes (P < 0.05). Both CV and superior joint space (SJS) presented a good diagnostic accuracy for NADP-ADDwoR [area under the curve (AUC)CV = 0.813; AUCSJS = 0.855)], and ADDwR-ADDwoR (AUCCV = 0.858; AUCSJS = 0.801). CSA presented a good diagnostic accuracy for ADDwR-ADDwoR (AUC = 0.813). A multivariate logistic ordinal regression model showed that the CV [odds ratio (OR) = 1.011; regression coefficient (RC) = 0.011, P = 0.018], SJS (OR, 8.817; RC = 2.177; P < 0.001), and medial joint space (MJS) (OR, 1.492; RC = 0.400; P = 0.047) had a significantly impact on the groups. Conclusion: CV, CSA, SJS, and MJS were significantly associated with the different disc status, and the condyle in ADD exhibited 3-dimensionally altered dimensions. They could be considered as promising biometric markers to assess the ADD. [ABSTRACT FROM AUTHOR]

Microscopic perforations in brachiopod shells, such as endopunctae, pseudopunctae, extropunctae, aditicules and epipunctae, have various biological functions. Based on excellently preserved material, aditicules are found to be widely developed in the Fusichonetes and Neochonetes, and setae‐bearing aditicules are shown to exist in rugosochonetid brachiopods for the first time. SEM and Micro‐CT images show that aditicules obliquely insert into the primary layer and are arranged in a single column along the crest of a costellae. The setae are supposed to play a role in triggering the closure of shells by sensing dangers, preventing large particles from entering the inner cavity and helping to increase the water pressure by forming a functional siphon. The SEM and Micro‐CT images also show that papillae are solid cones on the inner surface of the shell, and the density of papillae varies over different regions of the shell surface, and with environment. The variation in density of the papillae is most likely related to diverse functions in the 'filtering system'. In the marginal area, the small and densely spaced papillae can prevent intermediate and fine particles from entering the mantle cavity, whereas the large and sparse papillae in the mid‐valve can trap fine particles. In this study, these two microstructures are interpreted as a sediment 'filtering system' in Fusichonetes and Neochonetes, which is corroborated by the predominant occurrence of these genera in shallow‐water clastic shelves and deep‐water siliceous basins across the Permian–Triassic boundary interval in South China. [ABSTRACT FROM AUTHOR]

Objectives: This retrospective study explored the incidence of independent distal-lingual root (DLR) in mandibular first molars and the morphologic features of distal furcations through cone beam computed tomography (CBCT) in Beijing population., Methods: A total of 401 CBCT images of both mandibular first molars existed were included. The sex of the patients, the incidence of DLR, the distal root trunk length (DRT), the locations of distal furcation entrance (DFE), and the separation angle of distal furcation (ADF) were recorded., Results: The incidence rates of DLR were 33.2% on the subject level and 26.8% on the tooth level. The incidence of DLR was not different between genders but was higher on the right sides. The DRT values were 4.15 mm±1.02 mm. The ADF was 65.56°±11.56°. The DFE was located lingually, and 97.2% DFE was located more apically than buccal/lingual furcations., Conclusions: A high incidence of DLR was found in the Beijing population. The DRT was longer than buccal and lingual sites. The DFE was located lingually with a wide separation. Understanding the morphological features of distal furcation can help clinicians to make proper treatment plans.

Rationale and objectives: This study aimed to compare the volume computed tomography dose index (CTDIvol), dose length product (DLP), and size-specific dose estimate (SSDE), with the China and updated 2017 American College of Radiology (ACR) diagnostic reference levels (DRLs) in chest CT examinations of adults based on the water-equivalent diameter (Dw). Materials and methods: All chest CT examinations conducted without contrast administration from January 2020 to July 2020 were retrospectively included in this study. The Dw and SSDE of all examinations were calculated automatically by "teamplay". The CTDIvol and DLP were displayed on the DICOM-structured dose report in the console based on a 32cm phantom.The differences in patient CTDIvol, DLP, and SSDE values between groups were examined by the one-way ANOVA. The differences in patient CTDIvol, DLP, and SSDE values between the updated 2017 ACR and the China DRLs were examined with one sample t-tests. Results: In total 14666 chest examinations were conducted in our study. Patients were divided into four groups based on Dw:270 (1.84%) in 15–20 cm group, 10287 (70.14%) in the 21–25 cm group, 4097 (27.94%) in the 26–30 cm group, and 12 (0.08%) patients had sizes larger than 30 cm. CTDIvol, DLP, and SSDE increased as a function of Dw (p<0.05). CTDIvol was smaller than SSDE among groups (p<0.05). The mean CTDIvol and DLP values were lower than the 25th, 50th, and 75th percentile of the China DRLs (p <0.05). The CTDIvol, DLP, and SSDE were lower than the 50th and 75th percentiles of the updated 2017 ACR DRLs (p <0.05) among groups. Conclusions: SSDE takes into account the influence of the scanning parameters, patient size, and X-ray attenuation on the radiation dose, which can give a more realistic estimate of radiation exposure dose for patients undergoing CT examinations. Establishing hospital's own DRL according to CTDIvol and SSDE is very important even though the radiation dose is lower than the national DRLs. [ABSTRACT FROM AUTHOR]

Lips are the main part of the lower facial soft tissue and are vital to forensic facial approximation (FFA). Facial soft tissue thickness (FSTT) and linear measurements in three dimensions are used in the quantitative analysis of lip morphology. With most FSTT analysis methods, the surface of soft tissue is unexplicit. Our study aimed to determine FSTT and explore the relationship between the hard and soft tissues of lips in different skeletal occlusions based on cone-beam CT (CBCT) and 3dMD images in a Chinese population. The FSTT of 11 landmarks in CBCT and 29 lip measurements in CBCT and 3dMD of 180 healthy Chinese individuals (90 males, 90 females) between 18 and 30 years were analyzed. The subjects were randomly divided into two groups with different skeletal occlusions distributed equally: 156 subjects in the experimental group to establish the prediction regression formulae of lip morphology and 24 subjects in the test group to assess the accuracy of the formulae. The results indicated that FSTT in the lower lip region varied among different skeletal occlusions. Furthermore, sex discrepancy was noted in the FSTT in midline landmarks and linear measurements. Measurements showing the highest correlation between soft and hard tissues were between total upper lip height and Ns-Pr (0.563 in males, 0.651 in females). The stepwise multiple regression equations were verified to be reliable with an average error of 1.246 mm. The method of combining CBCT with 3dMD provides a new perspective in predicting lip morphology and expands the database for FFA. [ABSTRACT FROM AUTHOR]

• Head-to-head comparison reveals superior diagnostic performance of cone-beam breast computed tomography over mammography for primary breast cancer. • Z-test indicates significantly higher sensitivity of cone-beam breast computed tomography compared to mammography. • Cone-beam breast computed tomography and mammography have similar specificity in diagnosing primary breast cancer. To compare the diagnostic performance of cone-beam breast computed tomography (CBBCT) and mammography (MG) in primary breast cancer. PubMed, Embase, Web of Science, China National Knowledge Infrastructure, WanFang DATA, and China Science and Technology Journal databases were searched comprehensively from inception to March 2023. Sensitivity and specificity were calculated using bivariate random-effects models, and a summary receiver operating characteristic (SROC) curve was constructed. Bivariate I2 statistics and meta-regression analyses were also performed. The differences in diagnostic performance between CBBCT and MG were analysed using Z-test statistics. Clinical utility was explored using Fagan's nomogram, and quality assessment was conducted utilising the Quality Assessment of Diagnostic Accuracy Studies-2 checklist. The summary sensitivity and specificity for CBBCT in diagnosing primary breast cancer were 0.92 (95 % CI: 0.87–0.94) and 0.79 (95 % CI: 0.71–0.85), respectively, and the area under the curve (AUC) of the SROC was 0.93 (95 % CI: 0.90–0.95). For MG, the summary sensitivity and specificity were 0.77 (95 % CI: 0.69–0.83) and 0.75 (95 % CI: 0.66–0.82), respectively, with an AUC of 0.83 (95 % CI: 0.80–0.86). The Z-test revealed that the summary sensitivity of CBBCT was significantly higher than that of MG (P < 0.001). Additionally, the summary AUC of CBBCT was significantly higher than that of MG (P < 0.001). The diagnostic performance of CBBCT for primary breast cancer was better than that of MG. However, the results of both the CBBCT and MG are based on studies with small sample sizes. Further studies with larger sample sizes and more comprehensive designs are required to address this issue. [ABSTRACT FROM AUTHOR]

Purpose: To determine the thickness of the facial bone wall and the sagittal angulation between the long axis of the teeth and the long axis of the associated alveolar bone in the maxillary esthetic zone using cone beam computed tomography (CBCT). Materials and Methods: A retrospective radiographic study of CBCT images was conducted in 300 patients. The distance between the cementoenamel junction (CEJ) and the facial bone crest, the thickness of the facial bone wall (4 mm apical to the CEJ and midroot), and the sagittal angle between the long axis of teeth and the long axis of the respective alveolar bone were measured. Descriptive statistics and frequency analyses were performed. Results: The sample included 133 men and 167 women (mean age, 36.9 years; range, 18 to 60 years). The distance between the CEJ and the facial bone crest varied between 0.1 and 4 mm and showed an overall tendency to increase with age. Almost 80% of anterior teeth and 40% of premolars exhibited a thin facial bone wall (< 1 mm), and nearly 30% of sites had a bone wall thinner than 0.5 mm. The sagittal angle at approximately 80% of central incisor and second premolar sites was < 20 degrees, but the angle at more than 40% of canine sites was ≥ 30 degrees. There was a significant decrease in facial bone wall thickness from premolars to anterior teeth. Conclusion: The facial bone wall in most maxillary anterior teeth was very thin. There was a substantial sagittal angulation between the long axes of teeth and those of their respective alveolar bone in most esthetic zone positions. CBCT analyses of the facial bone wall and the sagittal angle are recommended to ensure the most appropriate dental implant treatment approach. [ABSTRACT FROM AUTHOR]

The radiation doses absorbed by major organs of males and females were studied from three types of dental X-ray devices. The absorbed doses from cone-beam computed tomography (CBCT), panoramic and intraoral X-ray machines were in the range of 0.23–1314.85 μGy, and were observed to be high in organs and tissues located in or adjacent to the irradiated area, there were discrepancies in organ doses between male and female. Thyroid, salivary gland, eye lens and brain were the organs that received higher absorbed doses. The organ absorbed doses were considerably lower than the diagnostic reference level for dental radiography in China. The calculated effective radiation doses for males and females were 56.63, 8.15, 2.56 μSv and 55.18, 8.99, 2.39 μSv, respectively, when using CBCT, the panoramic X-ray machine and intraoral X-ray machine. The effective radiation dose caused by CBCT was much higher than those of panoramic and intraoral X-ray machines. [ABSTRACT FROM AUTHOR]

BACKGROUND: Studies have shown that the osteogenic ability of 10% strontium-doped calcium hydrogen phosphate dihydrate is higher than that of calcium hydrogen phosphate dihydrate and 5% strontium-doped calcium hydrogen phosphate dihydrate, but also found that the pore structure of 10% strontium-doped calcium hydrogenphosphate dihydrate is not ideal, and the early osteogenic effect is not satisfactory. OBJECTIVE: To investigate the osteogenic effect of the composite of 10% strontium-doped calcium hydrogenphosphate dehydrate and gelatin and recombinant human bone morphogenetic protein 2/7(rhBMP2/7). METHODS: Gelatin-10% strontium-doped calcium hydrogenphosphate dihydrate and gelatin-10% strontium-doped calcium hydrogenphosphate dihydrate material containing 0.04 g/L and 1 g/L rhBMP2/7 were prepared respectively. Forty-five rabbit models of bilateral mandibular defects were prepared and then divided into five groups. In the blank control group, no material was implanted. 10% strontium-doped calcium hydrogen phosphate dihydrate(control group) and gelatin-10% strontium-doped calcium hydrogen phosphate dihydrate(gelatin group), 0.04 g/L rhBMP2/7-gelatin-10% strontium-doped calcium hydrogenphosphate dihydrate(0.04 g/L rhBMP2/7 group), and 1 g/L rhBMP2/7-gelatin-10% strontium-doped calcium hydrogenphosphate dihydrate(1 g/L rhBMP2/7 group) were implanted in the remaining four groups, respectively. Bone defect specimens were taken at 4, 8 and 12 weeks after surgery, and were examined by cone beam CT and immunohistochemistry. This study was approved by the Animal Ethics Committee of North China University of Science and Technology, China. RESULTS AND CONCLUSION: Cone beam CT examination revealed that at 8 weeks after surgery, bone repair was basically completed and the new bone tissue was almost fused with the surrounding tissue in the 1 g/L rhBMP2/7 group. Most of defect area was repaired, and the edge of new bone was unsmooth in the 0.04 g/L rhBMP2/7 and gelatin groups. Bone defect in the control group partially repaired. At 12 weeks after surgery, bone repair was completed in the gelatin, 0.04 rhBMP2/7 and 1 g/L rhBMP2/7 groups. Immunohistochemistry revealed that at 4 and 8 weeks after surgery, type Ⅰ collagen expression in the 1 g/L rhBMP2/7 group was significantly higher than that in the other four groups(P < 0.05). Type Ⅰ collagen expression in the 0.04 g/L rhBMP2/7 and gelatin groups was significantly higher than that in the control group(P < 0.05). At 12 weeks after surgery, there was no significant difference in type Ⅰ collagen expression between collagen, gelatin, 0.04 rhBMP2/7 and 1 g/L rhBMP2/7 groups(P > 0.05). These results suggest that the addition of gelatin and 1 g/L rhBMP2/7 to 10% strontium-doped calcium hydrogenphosphate dihydrate can promote the repair of bone defects. [ABSTRACT FROM AUTHOR]

Background: The anatomical relationship between the root apices of maxillary molars and the maxillary sinus floor (MSF) is important for the treatment of dental implantations and endodontic procedures. In this study, the detailed anatomical relationships between the root apices of maxillary molars and the MSF were studied in a Chinese population using CBCT. Methods: We collected the CBCT data files of patients who visited the stomatology outpatient clinic in Shanghai Fifth People's Hospital, Fudan University from January 1, 2017 to January 1, 2019 and measured the following items: the distance between the molar root apices and the MSF, the thickness of the mucosa and cortical bone of the MSF closest to the root apices, and the angle between the buccal and palatal roots. Results: The shortest distances between the root apices and the MSF were 1.57 ± 3.33 mm (the mesiobuccal root of the left second molar) and 1.61 ± 3.37 mm (the mesiobuccal root of the right second molar). Apical protrusion over the inferior wall of the sinus most often occurred in the mesiobuccal root of left second molar (frequency, 20.5%). The mucosa of the MSF was thinnest at the distobuccal root of the right second molar (1.52 ± 0.85 mm), the cortical bone of the MSF was thinnest at the mesiobuccal root of the right second molar (0.46 ± 0.28 mm), and the angle between the buccal and palatal roots ranged from 12.01° to 124.2° (42.36 ± 24.33 °). Conclusions: Among the root apices of the maxillary molars, the mesiobuccal root apex of the left second molar was closest to the MSF, and it had the highest incidence of protrusion into the sinus. The unique anatomical relationship between the maxillary molars and the MSF in this Chinese population is critical for treatment planning for dental implantation or endodontic procedures. [ABSTRACT FROM AUTHOR]

This retrospective study aims to analyze the root canal morphology of permanent mandibular incisors and the bifurcating/merging sites of root canal systems in children aged 9–12 in a Chinese subpopulation.Design Cone-beam computed tomography scans of 976 healthy, untreated and fully developed mandibular incisors were collected. Root canal morphology was identified by Vertucci's classification. Combined three-dimensional reconstruction and visualization techniques were used to locate bifurcating/merging sites in root canals. Vertucci I was the most common classification of mandibular central incisors (42.3%) while Vertucci III was most common in mandibular lateral incisors (37.9%). Females more frequently showed Vertucci I classification (49.5% central incisors and 36.7% lateral incisors) while Vertucci III was most common among males (44.5% central incisors and 41.0% lateral incisors). The difference in canal classification by sex was statistically significant (p < 0.05). 58.7% of Vertucci V canals bifurcated in the apical third (AT) in central incisors, while 69.5% bifurcated in the middle third (MT) in lateral incisors. Bifurcating and merging in AT (44.3%) was the most common style of Vertucci III canals in central incisors, while bifurcating in MT and merging in AT (53.8%) was the most common in lateral incisors. The root canal morphology of mandibular incisors in children aged 9–12 was different from that reported in previous studies on adults, and closely related to sex. Males had significantly greater canal variability than females. Lateral incisors had greater canal variability than central incisors. The bifurcating/merging sites were closely related to tooth type. • First study of canal morphology on permanent incisors of Chinese under 12 years-old. • In mandibular incisor of children, male has higher canal variability. • Mandibular incisor of children has more varied root canal system than adults. • Combined 3D reconstruction is used to locate bifurcating/merging site. • Bifurcating/merging site of canal is closely related to dental position. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the prevalence, location, and morphology of the mandibular lingual foramen (MLF), mandibular incisive canal (MIC), and anterior loop of the inferior alveolar canal (ALC) in a Chinese population using cone-beam CT (CBCT). Materials and methods: From 2014 to 2016, CBCT images from patients with various scanning purposes were obtained from the database of the Affiliated Stomatology Hospital of Kunming Medical University, China. Imaging analyses of the MLF, MIC, and ALC were performed via the NNT viewer software. The prevalence, location, length, classification of MLF, and its distances to the alveolar crest and the lower border of mandible were investigated, and the prevalence and length of MIC and the prevalence of ALC were also studied. Results: This study examined 1008 subjects, 521 (51.7%) males, and 487 (48.3%) females. 916 (90.9%) subjects showed the medial lingual foramina (LF), a single medial LF with the supraspinous-type predominating. Lateral LF were observed in 547 (54.3%) subjects mostly located in the premolar areas. 876 (86.9%) subjects had the MIC on the left side, whereas 877 (87.0%) had the MIC on the right side. The ALC was present in 147 (14.6%) subjects. Conclusions: This study showed a high prevalence of LF and MIC in the Southwest Chinese population. Therefore, caution should be taken during the implant treatment at the anterior mandible region. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The skin marking method (SMM) and bow-form-ruler marking method (BFRM) are two commonly used patient marking methods in mainland China. This study aims to evaluate SMM and BFRM by comparing the inter-fraction setup errors from using these two methods together with vacuum cushion immobilization in patients underwent radiotherapy for different treatment sites. MATERIALS AND METHODS: Eighteen patients diagnosed with pelvic, abdominal and thoracic malignant tumors (with 6 patients per treatment site) were enrolled in this prospective study. All patients were immobilized with vacuum cushion. Each patient was marked by both SMM and BFRM before computed tomography (CT) simulation. Target location was verified by cone beam CT images with displacements assessed prior to each sampled treatment session. The localization errors in three translational and three rotational directions were recorded and analyzed. RESULTS: Images from 108 fractions in 18 patients produced 324 translational and 324 rotational comparisons for SMM and BFRM. The setup errors of all treatment sites showed no difference in two marking methods in any directions (p > 0.05). In subgroups of treatment site analysis, SMM significantly lessened the lateral and yaw setup errors compared to BFRM in the pelvic sites (0.39±1.85 mm vs –1.28±1.13 mm, p < 0.01 and –0.19±0.59° vs –0.61±0.59°, p < 0.05). However, in the abdominal subgroup, BFRM was superior to SMM for reduced vertical errors (0.17±2.73 mm vs 2.28±3.16 mm, p < 0.05). For the underweight or obese patients (with Body Mass Index, BMI < 18.5 or BMI≥24), SMM resulted in less yaw errors compared to BFRM (–0.05±0.38° vs –0.43±0.48°, p < 0.05). No significant difference between SMM and BFRM in setup errors of normal weighted patients (18.5≤BMI < 24) was observed for all three studied treatment sites. CONCLUSIONS: This study shows no significant difference in patient setup errors for various treatment sites between SMM and BFRM in general. SMM may be suitable for the pelvic tumor and patients with BMI < 18.5 or BMI≥24, while BFRM is recommended for the abdominal tumor sites. [ABSTRACT FROM AUTHOR]

Background: Superior semicircular canal dehiscence syndrome (SSCD) is a current diagnosis that is due to a loss of bone covering the superior semicircular canal (SSC). This results in pressure-/sound- induced vertigo and oscillopsia. Objective: To find the variation of the thickness of the bone that covers the Superior Semicircular Canal with relation to age and gender among the Chinese descents. Materials and methods: Three hundred and eleven temporal bone Cone Beam Computed Tomography (CBCT) images of patients who attended Otology clinic at Second Hospital of Shandong University from January, 2017 to April, 2018 were retrospectively studied. The images were reconstructed in the line of Poschl and the thinnest area of the bone covering the SSC was taken. Results: We included 172 (55.31%) females and 139 (44.69%) males. Mean age was 41 years. Overall mean difference in thickness was found to be –0.0210. There was no significant difference between the female and male bone thickness (p =.7113). With age the mean difference was 0.0801 (p =.1557) which was not statistically significant. Conclusion and significance: There was no significant change in bone thickness with advancing age. CBCT is the best method of assessing SSCD. [ABSTRACT FROM AUTHOR]

Background: As multisection spiral computed tomography (MSCT) have been extensively used, it is important to consider the amounts of doses the patients are exposed during a computed tomography (CT) examination. The aim of the current study was to summarize MSCT doses in Chinese patients to establish the diagnostic reference levels (DRLs). Methods: Radiation dose metrics were retrospectively collected from 164,073 CT examinations via the Radimetrics Enterprise Platform. Radiation dose metrics (volume CT dose index [CTDIvol], dose-length product [DLP], effective dose [ED], and organ dose) and size-specific dose estimate (SSDE) were calculated for adults and children based on anatomic area and scanner type. Results: The median CTDIvol and DLP values were highest in the head at 51.7 mGy (interquartile range [IQR], 33.2-51.7 mGy) and 906.5 mGy·cm (IQR, 582.4--1068.2 mGy·cm) and lowest in the chest at 7.9 mGy (IQR, 7.9-10.3 mGy) and 284.8 mGy·cm (IQR, 249.0-412.6 mGy·cm), respectively. The median SSDE values of chest and pelvis were 12.1 mGy (IQR, 10.8-14.1 mGy) and 36.3 mGy (IQR, 34.0-38.9 mGy), respectively. EDs for children were similar to adults except for an increased 1.5-, 0.77-, and 1.7-fold in the chest, neck, and pelvis, respectively (p < 0.001). Furthermore, radiation doses tended to increase with increasing slice number and decrease when exposure reduction techniques were used. Conclusion: Our findings provide a basis for the evaluation of CT radiation doses and evidence for establishment of DRLs in China. [ABSTRACT FROM AUTHOR]

Introduction Apical surgery on the separate distolingual (DL) root of a 3-rooted mandibular first molar is thought to be difficult because DL roots are always severely curved, small, and shorter than distobuccal (DB) roots, and they are located far from the buccal cortical bone. The purpose of this study was to use cone-beam computed tomographic images to investigate the apical surgery–related morphological characteristics of DL roots in a Chinese population. Methods The screening process identified 83 subjects with 128 mandibular first molars with separate DL roots. The degree of root canal curvature was measured in the mesiodistal (MD) and buccolingual (BL) planes using the Schneider method. Distances were measured from the DL root apex to the buccal cortical bone, to the buccal cortical bone opposite the DB root apex, and to the buccal cortical bone opposite the mesiobuccal (MB) root apex. The lengths of the remaining DB, MB, and DL roots were measured after resection of 3 mm of the DL apical root. Angulations of the DL root canal were determined before and after DL apical root resection. Results The teeth were classified into 3 types: type I, straight in the MD and BL planes; type II, straight in the MD plane and curved in the BL plane; and type III, curved in the MD and BL planes. Only 5 molars (3.9%) were classified as type I, whereas 52 (40.6%) molars were type II and 71 (55.5%) molars were type III. The type I DL root has a significantly shorter length and longer distance from the DL root apex to the buccal cortical bone than type II and III roots ( P < .05). The distance from the DL root apex to the buccal cortical bone opposite the MB root apex is significantly longer than the distance to the buccal cortical bone opposite the DB root apex in types I and II ( P < .05), whereas the distance is nearly equal for type III. The angulations for root-end preparation of types II and III DL roots vary from 57.5° to 129.1° and from 55.8° to 128.1°, respectively. Conclusions A new classification was proposed for DL roots in 3-rooted mandibular first molars based on the root canal curvature. Type I is unsuitable for apical surgery. Access to the type II DL root apex should be through the DB root apex, whereas access to the type III DL root apex through the MB root apex is more feasible. Apical surgery on types II and III DL roots may be accomplished when the depth of the root-end preparation is reasonably reduced, and fine and personalized angulated ultrasonic retro tips are used. [ABSTRACT FROM AUTHOR]

A present limitation of forensic anthropology practice in China is the lack of population-specific criteria on contemporary human skeletons. In this study, a sample of 203 maxillofacial Cone beam computed tomography (CBCT) images, including 96 male and 107 female cases (20-65 years old), was analyzed to explore mandible sexual dimorphism in a population of contemporary adult Han Chinese to investigate the potential use of the mandible as sex indicator. A three-dimensional image from mandible CBCT scans was reconstructed using the SimPlant Pro 11.40 software. Nine linear and two angular parameters were measured. Discriminant function analysis (DFA) and logistic regression analysis (LRA) were used to develop the mathematics models for sex determination. All of the linear measurements studied and one angular measurement were found to be sexually dimorphic, with the maximum mandibular length and bi-condylar breadth being the most dimorphic by univariate DFA and LRA respectively. The cross-validated sex allocation accuracies on multivariate were ranged from 84.2% (direct DFA), 83.5% (direct LRA), 83.3% (stepwise DFA) to 80.5% (stepwise LRA). In general, multivariate DFA yielded a higher accuracy and LRA obtained a lower sex bias, and therefore both DFA and LRA had their own advantages for sex determination by the mandible in this sample. These results suggest that the mandible expresses sexual dimorphism in the contemporary adult Han Chinese population, indicating an excellent sexual discriminatory ability. Cone beam computed tomography scanning can be used as alternative source for contemporary osteometric techniques. [ABSTRACT FROM AUTHOR]

Objective To evaluate the significance of first premolar root concavity on clinical indices of chronic periodontal disease and alveolar bone defects. Methods Three-dimensional reconstruction by cone beam computed tomography was used to observe root surface anatomy and the type of alveolar bone defect seen in the mesial and distal sites of 272 first premolars from 99 patients who had presented with chronic periodontitis. Periodontal clinical indicators at each site were measured using a Florida Probe Corporation (Gainesville, FL, USA). Results The incidence of mesial and distal root concavities of the maxillary first premolars was 100% and 39.3% respectively, and in the mandibular, the incidence was 42.5% and 31.3% respectively. The distributions of the different types of concavities in terms of both age and gender of the patients were not statistically significant. The mean probing depth and clinical attachment loss of the first premolars with root concavities were significantly higher than those without concavity ( p < 0.05). Plaque accumulation was significantly different in the premolars with/without root concavities ( p < 0.001). The type of alveolar bone defects with concavities was significantly different from those without concavities ( p < 0.05). Ramp shape bone defects were dominant for teeth without concavities, while crater shape was seen for teeth with concavities. Conclusion Root concavities of the first premolars were associated with periodontal disease, and the type of interproximal alveolar bone defect. Root concavities may be important in contributing to local periodontal disease of the first premolars. [ABSTRACT FROM AUTHOR]

Background/Purpose: More detailed knowledge of root and canal morphology is important in order to improve the success in the endodontics of primary teeth. The purpose of this study was to evaluate the root and canal morphology of primary mandibular second molars (PMSMs) in a Chinese population using cone-beam computed tomography (CBCT). Methods: CBCT images, which had been obtained previously in the West China Hospital of Stomatology at Sichuan University, Chengdu, China between May 2009 and December 2011, were screened retrospectively. Finally, 283 individuals—207 male and 76 female with a mean age of 7.2 years (range 3–10 years)—and 487 PMSMs with clear images of root and canal morphology were enrolled. The number of roots and morphology of canals were recorded. The patient's gender, and the symmetry and frequency of three roots in PMSMs were analyzed. Results: The majority of PMSMs had two (72.28%) or three roots (27.52%). The symmetrical incidence of three-root PMSMs in this Chinese population was 50.65%. There is no difference between genders in the prevalence of an extra root and the incidence of symmetry (p > 0.05). Of the individuals enrolled, 25.26% of PMSMs had three canals and 73.31% had four canals. The root canal systems of the PMSMs in the present study were categorized into seven variants. Conclusion: This study indicated that three-rooted PMSMs occur frequently in the Chinese population. There was no difference between the two genders on incidence and symmetry. The majority of PMSMs have three to four canals and the diversity of the root canal variants should be considered when performing clinical procedures. CBCT is a good option for studying the root and canal morphology of primary teeth. [Copyright &y& Elsevier]

Abstract: Introduction: Successful root canal treatment is dependent on detailed knowledge of the morphology of the root canal system. The aim of this study was to investigate the morphology of the root canal systems of mandibular first premolars and the location of root canal orifices and apical foramina in a Chinese subpopulation using cone-beam computed tomography scanning. Methods: A total of 440 cone-beam computed tomographic images of mandibular first premolars were obtained from 238 patients. Tooth position, root canal morphology, the distance between the apical foramen and the anatomic apex, and the distance between the 2 root canal orifices of mandibular first premolars with 2 root canals were investigated. The Fisher exact test was used to analyze the correlation between the number of root canals and tooth position. Results: Overall, 1.14% (n = 5) of the teeth had a C-shaped root canal system, 77.14% (n = 335) had 1 root canal, and 22.05% (n = 97) had 2 root canals from type II to type V. The remaining 0.68% (n = 3) were classified as type VIII, which had 3 root canals. The most frequent distribution of the distance between the apical foramen and the anatomic apex in 335 mandibular first premolars with 1 root canal was 1–2 mm (n = 192). The distance between the apical foramen and the anatomic apex of mandibular first premolars with 2 root canals was in accord with that of mandibular first premolars with 1 root canal. The distance between the 2 root canal orifices of mandibular first premolars with 2 root canals was approximately 13 mm. Conclusions: Most mandibular first premolars had 1 root canal. More than 1 of 5 mandibular first premolars had complex root canal systems (with 2 or more root canals). This study provides supplemental information about the root canals of mandibular first premolars in a Chinese subpopulation. [Copyright &y& Elsevier]

• Anatomic study of a prehistoric Chinese population from the Neolithic era. • High prevalence of C-shaped canals in the mandibular second molars. • C-shaped canals and their variants of prehistoric and contemporary clinical cases. The aim of this study was to analyze the occurrence and variations in C-shaped canals in ancient Chinese teeth and compare the differences of these features between ancient and age-matched modern populations. Approximately 5000-year-old craniofacial bone remains were collected from the fossils of 38 individuals (total: 68 mandibular second molars) excavated from the Jiaojia site. The control group comprised of an equal number of randomly selected modern samples. We used cone-beam computed tomography to scan the mandible along the apex-crown axis and analyzed the canal morphology, based on Fan's categorization criterion, at 2 mm, 5 mm, and 8 mm to the apical level. Grooves on the lingual and buccal sides were also recorded. The proportion of C-shaped roots among ancient samples on the left and right sides were 48.57 % (17/35 teeth) and 54.55 % (18/33 teeth), respectively, and 51.47 % (35/68 teeth) in the total sample. Conversely, in the control group, 44.12 % (15/34) and 38.24 % (13/34) occurred on the left and right sides, respectively, and 41.18 % (28/68) in the total sample. Among the C-shaped canals from the Jiaojia site samples, the classification type changed between two adjacent levels in 84.31 % of samples. Approximately 35 (51.5 %) teeth had a fused root, 20 (29.41 %) had one shallow buccal and one deep lingual groove. The occurrence of C-shape variation was not significantly correlated with time (p ＞0.05). This study identified a high rate of C-shaped root canals among individuals of Jiaojia who lived approximately 5000 years ago. [ABSTRACT FROM AUTHOR]

• Facial soft tissue depth of Yangtze River Delta Han was measured using Cone beam CT. • Up to 55 facial landmarks were measured in each sample. • Facial reconstructions of Yangtze River Delta Han population was assisted. Facial approximation plays a vital role in personal identification when other methods cannot be applied, and the study on facial soft tissue thickness (FSTT) is important to allow more accurate facial approximation. The Cone-Beam CT (CBCT) is considered to be an accurate approach in assessing FSTT, however only few studies have assessed the FSTT norms by CBCT in Chinese populations. The aim of this study was to (1) establish forensic measurement approach on a 3D model reconstructed by CBCT image; (2) obtain FSTT norms from the adults of Yangtze River delta Han population; (3) determine the impacts of sex, age, BMI as well as malocclusion type on FSTT and (4) form a FSTT database through CBCT. A total of 60 facial landmarks were primarily established from 3D reconstructed models from CBCT images of 424 healthy Han adults (130 males and 294 females) aged from 21 to 50 years in Yangtze River delta region and measurements were carried out. The multivariate analysis of variance test and multiple linear regressions test showed that the FSTT values on most landmarks were significantly different between sexes and BMI, and males showed greater values, expect for the landmarks distributed in malarzygomatic areas. Simultaneously, BMI mostly affected the landmarks located in zygomatic region. Besides, only a few landmarks were influenced by age. Interestingly, several periodontal landmarks were influenced by malocclusion types, thus the impact of malocclusion types on FSTT requires attention. Finally, the validation analysis suggested that measurement approach is an important factor for FSTT. [ABSTRACT FROM AUTHOR]

The purpose of this study was to obtain the morphological data of the maxillofacial region of Han nationality adults in Northeast China, and to explore the methods and appropriate variables of three-dimensional reconstruction technology for sex determination using Cone beam computer tomography (CBCT). The CBCT images of 420 adults (210 males, 210 females) aged 18-70years were reconstructed by MIMICS 17.0 software and sixteen observation indexes were measured and analyzed statistically. The results demonstrated that twelve of sixteen variables expressed significant sexual difference (p<0.01) which were as follows: mandibular angle (X1),area of mandibular foramen (X2), bi-gonial breadth (X3), koronoidbreite (X4), Height of symphysis (X5), Min-height of mandibular notch (X6), Min-breadth of mandibular ramus (X7), Buccal side bone thickness of MF (X8), Horizontal diameter of MF (X11), Vertical from prosthion to palatal breadth (X12), palatal breadth (X13), The ratio of HD-MF and VD-MF (X15). Then the sexual discriminant equation which was suitable for people at the age of 18-70 was established using stepwise method: Y=-0.059X1+0.313X2+0.1X3+0.061X4+0.044X5+0.041X6+0.076X13-17.215. It was found that the cross-validated grouped overall predictive accuracy was 87.4%. It could correctly identify males in 85.7% and females in 89% of the cases. This study has accumulated morphological data of maxillofacial skeleton from adults of Han nationality in Northeast China, which provided guiding significance for sex determination and clinical application in forensic science, archaeology, criminal investigation, iconography and clinical three-dimensional (3D) print. Evaluation variables and related discriminant functions of sex determination using CBCT for three-dimensional reconstruction technology provided a new theoretical basis and practical means for sex determination. [ABSTRACT FROM AUTHOR]