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Background: Pulp stones are a type of pulp calcification, the presence of which tends to hinder endodontic treatment. Thus, this retrospective study aimed to analyze the distribution of pulp stones in the population in southwest China and identify the influencing factors. Materials: Cone-beam computed tomography (CBCT) scans of 5066 teeth of 200 patients (91 males and 109 females) aged 16–45 years were evaluated. Pulp stones were marked as either present or absent when distinct radiopaque masses were found in the pulp cavity, then evaluated the occurrence of pulp stones with regard to tooth type, sex, age group, and contact it with tooth status. The Pearson chi-square test and nonparametric test were used for statistical analysis. Results: Pulp stones were detected in 49.0% of patients and 7.4% of teeth, respectively. The incidence in females was 1.9 times higher than in males (OR = 1.9, 95% CI = 1.1–3.3, p = 0.001). Pulp stones were most prevalent in patients 36–45 years of age. Furthermore, in the age range of 16–45 years, the likelihood of finding pulp stones increased 1.1 times per year with age (OR = 1.1, 95% CI = 1.0–1.1, p = 0.032). A higher incidence of pulp stones was observed in the maxilla and molars. Of the 5066 teeth studied, pulp stones were more common in non-intact teeth. Conclusion: Nearly half of the population in southwest China had pulp stones. Pulp stones were found significantly more often in females, maxilla, and non-intact teeth, and their frequency increased with age. For dentists, understanding the distribution of pulp stones is crucial for the proper design of root canal treatment (RCT). Trial registration: This study was approved by the Ethics Committee of the Affiliated Hospital of Stomatology, Southwest Medical University (certificate number: 20220818001). [ABSTRACT FROM AUTHOR]

Background: Understanding the tooth anatomy is crucial for ensuring effective endodontic treatment. This study investigated the root canal morphology of the second mesiobuccal (MB2) canal in maxillary first molars (MFMs) in a Chinese population using cone-beam computed tomography (CBCT). Methods: This study evaluated 486 MFMs with MB2 canals from 285 participants undergoing CBCT examination and determined the Vertucci's classification and position of the MB2 canal orifice. The prevalence of the MB2 canal was correlated with the sex, age, and tooth side. The correlations between the prevalence of the MB2 canal and sex and tooth side were assessed using the Fisher's exact test. The chi-square test was used for evaluating the correlation between the prevalence of the MB2 canal and age. Results: The number of type II, III, IV, V, VI, VII, and other root canals in the MFMs was 30.9%, 0.6%, 65.0%, 1.2%, 1.2%, 0.4%, and 0.6%, respectively. Among the 201 cases with bilateral inclusion, 87.6% showed consistent canal configuration. Results of the first clear apparent position (FCAP) of the MB2 canals showed that 434, 44, and 3 teeth had FCAP at the upper, middle, and bottom one-third of the root, respectively. The FCAPs of the MB2 canal in the MFMs with types II, IV, and VI, as well as types III and V canals showed significant differences (p<0.05). The horizontal distance between the MB1 and MB2 canal orifices in the type II canals of MFMs was significantly lesser than those in the type IV canals of MFMs (p < 0.01). The longitudinal distance between the pulp chamber floor plane and MB2 canal orifice significantly correlated with age (p < 0.05). Conclusions: The morphology of the mesiobuccal root canal in the MFMs is complex. Complete understanding of the anatomical morphology of the root canal combined with the CBCT and dental operating microscope is necessary for the accurate detection of the MB2 canal and consequently improved success rate of root canal treatment. Our study findings can help endodontists improve endodontic treatment outcomes. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to survey the prevalence of C-shaped root canal system in mandibular first premolar in Chinese population by reading Cone-beam computed tomography (CBCT) images and to analyze its anatomical characteristics by CBCT and Micro–computed tomography (Micro-CT). Methods and materials: The prevalence and the morphologic features of C-shaped root canal system were evaluated by observing CBCT images of 760 patients (1520 mandibular first premolars). 66 mandibular first premolars with C-shaped root canal system were scanned by Micro-CT. The morphologic features including radicular groove, C-shaped root canal categories in the cross-sections and in the 3D models, accessory and connecting canals, apical foramina and accessory foramina, were analyzed using image software. Results: C-shaped root canal system was identified in 16.9% of mandibular first premolars. The minimum mesial wall thickness most commonly occurred at the lingual site (69.7%). Regarding to the cross-sectional classification, the maximum was C2 (41.5%). In the 3D classification, the most common was S (34.8%). Accessory canals were observed in 36.4% of the samples and occurred mostly in the middle and apical regions. 42.4% samples had 1–3 variable connecting canals, and 40.9% samples had only one apical foramen. Conclusions: The incidence of C-shaped root canal system in mandibular first premolars was 16.9% in the Chinese population. The anatomy was very complex and variable, mostly distributed in the middle and apical regions of the root canal. The mesial wall of C-shaped canal was extremely thin on the lingual side. [ABSTRACT FROM AUTHOR]

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]

The morphological changes based on deposition of secondary dentin and mineralization of the third molar have been proven to be related to chronological age. However, Kvaal's method on the theory of deposition of secondary dentin was controversial with respect to dental age estimation in the recent research. The aim of this study was to combine the parameters of Kvaal's method with relatively high correlation coefficients and mineralization stages of the third molar to improve the accuracy of predicting the dental age of subadults in northern China. A total of 340 digital orthopantomograms of subadults aged from 15 to 21 years were analysed. A training group was used to test the accuracy of the original Kvaal's method and to establish novel methods for subadults in northern China. A testing group was used to compare the accuracy of the newly established methods with the Kvaal's original method and with published method specifically used in northern China. To increase the feasibility of our estimation model, we combined the mineralization of the third molar to build a combined specific formula. The results showed that the combined specific model increased the coefficient of determination to 0.513, and the standard error of the estimate was reduced to 1.482 years. We concluded that the combined specific model based on the deposition of secondary dentin and mineralization of the third molar could improve the accuracy of dental age assessment of subadults in northern China. Key Points The decrease in the dental pulp cavity based on deposition of secondary dentin is a useful variable for assessing age. A total of 340 orthopantomographs were used in this research, including 278 in training groups and 62 in testing groups. Original Kvaal's method underestimated the dental age for subadults in northern China. The equation of combined specific method constructed in our study was proved more suitable to calculate dental age for subadults in northern China. [ABSTRACT FROM AUTHOR]

Purpose: To assess the pain relief effects and safety of transitional therapy (TT) in the treatment of posterior teeth of pregnant women with symptomatic irreversible pulpitis and symptomatic apical periodontitis. Methods: A prospective cohort clinical study was conducted in the Department of Stomatology at Shenzhen Maternity & Child Healthcare Hospital, China, from January 2017 to December 2019. We enrolled 62 pregnant women with acute dental pain caused by posterior teeth with symptomatic irreversible pulpitis or symptomatic apical periodontitis. Among the 62 participants, 34 received TT, and 28 chose nontreatment during pregnancy. We evaluated the pain relief with the verbal numerical rating scale (VNRS) scores of pain perception in the clinical study, as well as the anti-bacterial medicament filling conditions of canals of in vitro models. Moreover, we investigated the safety outcomes, such as gestational age, neonatal head circumstance, birth weight, and body length. Results: The VNRS scores of the participants treated with TT were significantly lower than those of the nontreatment group 2 days after treatment (P< 0.001). TT treated pregnant women experienced significantly more pain decreases in VNRS scores than their counterparts(P< 0.05). The optimal anti-bacterial medicament filling conditions of canals of in vitro models by TT method were comparable with those of canals instrumented with traditional RCT method. Moreover, no significant differences of safety outcomes were observed between pregnant women of these two groups. Conclusion: The transitional therapy is efficient in alleviating acute dental pain of posterior teeth of pregnant women with symptomatic irreversible pulpitis and symptomatic apical periodontitis, and maintaining painless chains throughout pregnancy with no adverse effects on neonatal birth outcomes. [ABSTRACT FROM AUTHOR]

Background: To evaluate the root anatomy, root canal morphology and the anatomical relationship between the roots and maxillary sinus of maxillary second premolars by CBCT in a western Chinese population. Methods: A total of 1118 CBCT scans of the maxillary second premolars were collected from West China Hospital of Stomatology, Sichuan University. Information below were measured on axial, coronal and sagittal sections, recorded and evaluated properly: the number of roots and canals, the morphology of canal system classified by Vertucci standard, the inter-orifice distance of canal orifices, the curvature of each canal and the distance from root tip to maxillary sinus floor. Results: Among the 1118 teeth, 94.2% (1053) are single-rooted and 55.1% (616) have one canal. Type I (55.1%) is the commonest root canal morphology followed by Type II (31.9%). The mean inter-orifice distance (IOD) for multi-canal teeth ranging from 2.72 ± 0.32 to 3.41 ± 0.11 mm. Of 1622 canals, 38.8% (630) curvature are mesiodistal and 30.9% (501) are straight canals. The distance from root tip to maxillary sinus floor increased with age and the mean distance of single-rooted ones is 2.47 ± 3.45 mm. Conclusions: All kinds of canal morphology category can be detected in maxillary second premolars. The IOD might be a predictable factor for root canal morphology. Roots of maxillary second premolars are related to maxillary sinus which should be treated carefully. [ABSTRACT FROM AUTHOR]

Introduction. Evidence of second canal in permanent mandibular incisors is frequently questioned in dentistry. The difference in evidence between the two teeth is an interesting argument across different countries and ethnicities. So the aim of the systematic review was to investigate the evidence of second canal between permanent mandibular central and lateral incisors in China. Materials and Methods. The papers were selected from the electronic databases and hand searching according to inclusion and exclusion criteria. All qualified studies were judged by the reviewers. The selected studies were checked with Joanna Briggs Institute Critical Appraisal tool for prevalence studies. Finally, three studies were selected for the review and meta-analyses. The proportion of the second canal with its confidence interval and forest plot for the meta-analyses were calculated. Results. The evidences of second canal in permanent mandibular central and lateral incisors in China were 5.6% and 14.1%. Only one study reported bilateral symmetry of the second canal as 58.7% and 76.1% in the two types of teeth. Out of all canal anatomies, Vertucci's type ΙΙΙ was dominant comprising 4.1% and 11.2% together with other second-canal types comprising 1.4% and 3% in permanent mandibular central and lateral incisors. When the proportions were meta-analyzed, mandibular central incisors had been less numerous OR = 0.35 [0.31, 0.40], 0.33[0.28, 0.39], and 0.42 [0.22, 0.79] in the evidence of second canal, of Type ΙΙΙ, and of other types except Type ΙΙΙ than mandibular lateral incisors in China. Out of all second-canal anatomies, Type ΙΙΙ presented 72.5% and 78.9% along with other second-canal types comprising 24.3% and 21.1% in the two teeth in China. Discussion. There was the evidence of second canal which deviated toward the permanent mandibular lateral incisor also in case of bilateral symmetry, the prevalence of Vertucci's Type ΙΙΙ, and other second-canal types out of all canal anatomies. [ABSTRACT FROM AUTHOR]

Objectives. To investigate the root morphology and root canal anatomy of maxillary first premolar using microscopic computed tomography (micro-CT). Methods. 324 maxillary first premolars were collected and scanned. -e root and canal diameter, canal wall thickness, root taper, and cross-sectional shapes were determined in the single root with 1 canal (SR1C), single root with 2 canals (SR2C), and 2 roots with 2 canals (2R2C) by micro-CT. Results. -e results showed that single-rooted maxillary premolars were more common than other types. -e incidence of SR1C, SR2C, and 2R2C reached 25%, 26.39%, and 26.39%, respectively. Root and canal diameters and canal wall thickness were decreased from coronal third to apical foramen. -e three parameters and canal taper showed increases from buccal and palatal (BP) to mesiodistal (MD) aspects.-eroot canal tapers were smallest of the middle third level.-efindings showed the different variations in 2R2C teeth.-eroot canal cross-sectional morphology in maxillary first premolars is complicated, including round, oval, long oval, flat canal, and irregular canal shapes. -e distribution varied in different aspects. Conclusion. Root canal morphology showed a wide variation and complicated structure. -e single-rooted teeth were more common in the Chinese adolescent population, and the majority of maxillary first premolars have two canals. [ABSTRACT FROM AUTHOR]

Aim: The purpose of this article is to determine the racial predilection of C-shaped canal configuration in a mandibular second molar. Background: Unusual root canal anatomy always poses a diagnostic and treatment challenge. Identification of such variation is important for the success of root canal treatment outcome. C-shaped canal configuration is such an aberrant morphology of molar teeth that vary in different population and is commonly seen in a mandibular second molar. Thus, knowledge of racial predilection of C-shaped canal configuration in different population for early diagnosis is obligatory. Materials and Methods: An exhaustive search was undertaken to identify published research articles related to C-shaped canal configuration in mandibular second molars. Forty-three research articles were analyzed which included 12,481 mandibular second molars. Chi-square test using value of P < 0.05 was performed to assess the statistical significance of this anomalous anatomic variation among the different population. Results: Statistical test revealed a significant variation between the Asian and nonAsian population. The highest incidence of racial predilection was observed in China (Asia) with 93.1%, and the minimum was observed in America with 2.7%. Conclusion: This research reported that racial predilection of C-shaped canal configuration in mandibular second molar varies significantly. [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]

Abstract: Introduction: Root fusion is an anatomic variation in maxillary second molars (MSMs); however, the nature of this canal morphology as it relates to its root anatomy has not been fully clarified. The purpose of this study was to investigate the relationship between features of fused roots and root canal anatomy in MSMs using micro–computed tomographic imaging. Methods: One hundred eighty-seven extracted MSMs were scanned with the μCT50 (Scanco Medical, Bassersdorf, Switzerland), and their root and canal morphology was classified and analyzed using the classifications proposed by Yang and Vertucci. The number and position of canals that merged were recorded and compared among different root fusion types. Results: One hundred eight (57.75%) MSMs had 3 separate roots, and 79 (42.25%) had fused roots. Of the 79 fused roots, 22 showed partial canal merging, and 6 had complete canal merging. Canal merging was found with teeth with 3-root fusion more often than in those with 2-root fusion (P < .05). Of 28 merged canals, 16 occurred between mesiobuccal and distobuccal canals and 9 among mesiobuccal, distobuccal, and palatal canals. Conclusions: MSMs with fused roots may present a complicated root canal system as a result of canal merging. [Copyright &y& Elsevier]

Objective. To determine sex differences in the tissue proportions of crowns of mandibular primary central incisors in Chinese children and to quantify the volume of crown components in three dimensions using micro-computed tomography (micro-CT). Materials and methods. The specimens used in this study were 41 mandibular first deciduous incisor teeth with intact crowns (21 males and 20 females) obtained from patients between 5-6 years of age. Each specimen was scanned using micro-CT at a resolution of 0.05 mm and 3D-rendered images were created. The volume of each component of the crown was measured and examined for differences in different sex and ages. Results. The pulp chamber volume decreased with age and the volume ratio of the pulp chamber to the whole crown was significantly smaller in 6-year-olds than in 5-year-olds ( p < 0.05). Conclusions. Males had significantly larger tooth crown volumes and dentin volumes than females did ( p < 0.001), while the volume of enamel showed no sexual dimorphism. [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]

Zheng Q, Zhang L, Zhou X, Wang Q, Wang Y, Tang L, Song F, Huang D. C-shaped root canal system in mandibular second molars in a Chinese population evaluated by cone-beam computed tomography. International Endodontic Journal, 44, 857-862, 2011. Abstract Aim To evaluate the anatomical features of C-shaped canal systems in Chinese mandibular second molars by cone-beam computed tomography (CBCT). Methodology A total of 608 patients of Chinese descent with healthy, well-developed mandibular second molars were enrolled. These patients were referred to the West China Hospital of Stomatology and required radiographic examination by CBCT as part of their routine dental treatment. Of the 608 examined CBCT images, 528 showed unilateral intact molars and 80 showed bilateral intact molars. Bilateral molar data were only used to analyse the distribution of unilateral and bilateral occurrences of C-shaped canals. The following in vivo CBCT observations were made: (i) frequency and type of root; (ii) frequency of C-shaped canals by gender, age and tooth position (left versus right); (iii) the classification of cross-sectional canal images of C-shaped canals; and (iv) unilateral and bilateral occurrences of C-shaped canals. Results Fused roots were present in 39% of molars. A C-shaped canal system was present in 39% of the teeth. This prevalence did not differ with gender, age and tooth position. Most (81%) of the C-shaped canals in individuals with bilateral molars were symmetrical. Most of the canals with uninterrupted 'C'-shapes appeared to divide into two or more canals towards the canal terminus. Conclusion There was high prevalence of C-shaped canals in the mandibular second molars of Chinese population. The canal systems varied considerably in their anatomical configuration. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: The purpose of this study was to investigate the canal morphology of 504 maxillary permanent teeth of subjects of Han nationality in Chinese Guanzhong area. Methods: Maxillary permanent teeth were randomly collected in Guanzhong area. After regular preparation, the teeth were immersed into ink without preparing access cavities and then put into hyperbaric oxygen chamber (0.6 Mpa) for 2 hours to let the ink penetrate into root canal from apical foramen, apical deltas and foramen of lateral canals under stable positive pressure. After demineralization and clearing, the following observations were made: (1) number of root canals, (2) root canal configuration by using Vertucci''s classification, (3) presence of lateral canals, and (4) frequency of apical deltas. Results: All the teeth were well-stained, and the fine details were well-revealed. Apical deltas (12.2%–83.3%) and lateral canals (13.7%–68.8%) could be frequently found in all types of maxillary teeth. Most of central incisors (95.8%), lateral incisors (91.4%), and canines (75.4%) displayed type I canal configuration, whereas most of first premolars (87.3%) and second premolars (72.3%) possessed 2 canals with type II, IV, or VI canal configuration. The majority of distobuccal roots and palatal roots of first molars (88.9%, 97.8%), second molars (92.0%, 94.0%), and third molars (87.5%, 91.6%) possessed type I canal configuration. The prevalence of mesiobuccal roots with type I configuration was 66.7% in maxillary first molars, 82% in second molars, and 62.5% in third molars. Conclusions: The modified technique of canal staining can effectively reveal detailed root canal system. The canal configuration of maxillary teeth in subjects of Han nationality in Chinese Guanzhong area is consistent with previous reports in other races. [Copyright &y& Elsevier]

Racial differences in dental crown morphology have long been recognised, but the diverse aspects of root form and canal anatomy of human teeth have not received the same attention. The majority of books on dental anatomy fail to supply detailed information of the features of root and root canal morphology that occur at particularly high frequency in Mongoloid populations. These features have not been systematically documented and the implications that these variations may have upon clinical endodontics have not been fully reported. In this study 100 mandibular first molars extracted from Hong Kong Chinese patients were examined visually and radiographically. For each tooth, the number of roots, root canals, and apical foramina were noted. Fifteen per cent of the mandibular first molars examined were found to be 3-rooted. Forty-five per cent of the sample displayed 2 distal canals and 28% of the teeth had 2 separate distal apical foramina. The frequency of the second distal canal is higher than the previously reported findings for non-Mongoloid groups. [ABSTRACT FROM AUTHOR]

Data sources Cochrane Library, PubMed, Ovid, ScienceDirect, Wiley, China Biology Medicine (CBM), China National Knowledge Infrastructure (CNKI), Wan Fang and VIP Database for Chinese Technical Periodicals (VIP) databases were searched for articles dating from January 2000 to July 2018. Studies in languages other than English or Chinese were excluded. Study selection Randomised controlled trials comparing the clinical effectiveness of calcium hydroxide to formocresol or camphor phenol in acute pulpitis of deciduous teeth requiring root canal treatment were included. The primary outcome was clinical effectiveness while the secondary outcome was incidence of endodontic inter-appointment emergencies. Data extraction and synthesis Two authors independently screened titles and abstracts of all studies identified through the search and reviewed full articles against established inclusion/exclusion criteria. Any disagreements between the authors were resolved by consensus or by consulting relevant experts. Risk of bias assessment was carried out using the Cochrane collaboration tool. Clinical effectiveness and incidence of inter-appointment endodontic emergencies were expressed as odds ratio and 95% CI. Heterogeneity was assessed using Q-test and I2 measurement. Appropriate models were used for meta-analysis based on heterogeneity. Results A total of 16 randomised trials informed the meta-analysis. Clinical effectiveness of calcium hydroxide was compared to formocresol in 12 studies and pooled data indicate that calcium hydroxide was significantly better in terms of clinical effectiveness (OR = 3.37; 95% CI 2.54 to 4.48), and was associated with significantly decreased inter-appointment emergency visits (OR = 0.26; 95% CI 0.16 to 0.42). Calcium hydroxide was compared to camphor phenol in seven studies and was shown to be significantly superior in its clinical effectiveness (OR = 5.50; 95% CI 3.36 to 8.98). Conclusions Limited available evidence suggest calcium hydroixide was superior to formocresol and camphor phenol as intracanal medicaments in the management of acute pulpitis in deciduous teeth. [ABSTRACT FROM AUTHOR]

• 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]

The article presents abstracts on dental research subjects including "Root Surface Caries in Hong Kong Chinese aged 35-44," by E. P. Corbet, R. W. Evans, C. J. Holmgren, and others, "Factors associated with tooth loss in a Hong Kong Chinese population," by A. Dimmer, and "The dental status of a group of cerebral palsied pre-school children in Hong Kong: a pilot study," by David O'Donnell.