Jayakumar Jayaraman

Northern Chinese dental ages estimated from southern Chinese reference datasets closely correlate with chronological age

While northern and southern Chinese are genetically correlated, there exists notable environmental differences in their living conditions. This study aimed to evaluate validity of the southern Chinese reference dataset for dental age estimation applied to northern Chinese. Dental panoramic tomographs of 437 northern Chinese aged 3 to 21 years were analysed. All the left maxillary and mandibular permanent teeth plus the 2 third molars on the right side were scored based on Demirjian’s classification of tooth development stages. Mean and standard error of dental age were obtained for each tooth development stage, followed by random effect meta-analysis for mean dental age estimation. Validity of the method was examined through measures of agreement (95% limits of agreement, standard error of measurement, and Lin’s concordance correlation coefficient) and measure of reliability (Intraclass correlation coefficient). On average, the estimated dental age overestimated chronological age by only around 1 month in both females and males. The Intraclass correlation coefficient values were 0.99 for both sexes, suggesting excellent reliability of the method. Reference dataset for dental age estimation developed on the basis of southern Chinese was applicable for use among the northern Chinese.

Demirjian’s method is unsuitable for dental age estimation

We read the article titled ‘‘Is Demirjian’s original method really useful for age estimation in a forensic context?’’ published in your journal [1]. We find that the study is well conducted but the title of this study is misleading. From the title it looked like the study had tested the Demirjian’s method on different population groups or that the authors had undertaken a review of the literature on the existing studies on Demirjian’s method, but the aim of the study was to assess the reliability of Demirjian’s method on a sample of Portuguese children. This is not reflected in the title. This study concluded that the method overestimated the age of both Portuguese boys and girls. While this study adds important information to the existing literature on the application of Demirjian’s method, the findings in this study are not a new; an earlier study on the Portuguese population also reported overestimation of age in both genders [2]. The use of Demirjian’s method has been questioned over several years as published studies in different population groups have consistently reported overestimation of age. The appropriate way to assess population differences is by applying Demirjian’s method on different population groups with stringent data collection and analysis taking into account of several factors in age estimation including number, age, and gender of the samples included in the analysis. Another approach is to conduct a systematic review of the literature on the studies that used Demirjian’s method. Both of these procedures have already been carried out. A study by Liversidge found group differences in the estimated age when using the Demirjian method on subject data from Europe, Middle East, Africa, India, China, and South America. The study concluded that Demirjian’s dental maturity method is inappropriate to assess population differences in dental maturity [3]. The first systematic review and meta-analysis on the studies that utilized Demirjian’s method was published by the DARLInG team in early 2013. We identified 34 studies from 22 countries that satisfied the inclusion criteria and found that Demirjian’s method on average overestimated the age by 6 months, sometimes up to 3 years [4]. Following this, another systematic review was published in the same year, which also reported a similar outcome. We later found that their review had several errors including the selection of articles and misinterpretation of data that had been subsequently published as comments to the article [5]. The use of Demirjian’s method for dental age estimation has always been problematic and several investigators have had difficulty in interpreting their data. The overestimation of age is just the beginning of the issues associated with this method. The most important area is that the statistical approach utilized to derive maturity scores is not understood. It is clear that the method is not designed to estimate dental age, which Demirjian and co-workers clearly mention in their original paper. They also warned about the existence of population differences in dental maturity [6]. Despite these warnings, the use of the method continues in different populations; the most recent was on a Tunisian population published in early 2016 [7]. There are several factors that determine the accuracy of the estimated age. While it has been shown physiological maturity differs with age, gender, and ethnicity, the additional influences of & Jayakumar Jayaraman jayakumar83@hotmail.com

Methodological and Reporting Quality of Systematic Reviews and Meta-analyses in Endodontics

Introduction: The aim of this systematic review (SR) was to evaluate the quality of SRs and meta‐analyses (MAs) in endodontics. Methods: A comprehensive literature search was conducted to identify relevant articles in the electronic databases from January 2000 to June 2017. Two reviewers independently assessed the articles for eligibility and data extraction. SRs and MAs on interventional studies with a minimum of 2 therapeutic strategies in endodontics were included in this SR. Methodologic and reporting quality were assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR) and Preferred Reporting Items for Systematic Review and Meta‐Analyses (PRISMA), respectively. The interobserver reliability was calculated using the Cohen kappa statistic. Statistical analysis with the level of significance at P < .05 was performed using Kruskal‐Wallis tests and simple linear regression analysis. Results: A total of 30 articles were selected for the current SR. Using AMSTAR, the item related to the scientific quality of studies used in conclusion was adhered by less than 40% of studies. Using PRISMA, 3 items were reported by less than 40% of studies, which were on objectives, protocol registration, and funding. No association was evident comparing the number of authors and country with quality. Statistical significance was observed when quality was compared among journals, with studies published as Cochrane reviews superior to those published in other journals. AMSTAR and PRISMA scores were significantly related. Conclusions: SRs in endodontics showed variability in both methodologic and reporting quality. HIGHLIGHTSThe overall methodologic quality and the reporting quality of included systematic reviews and meta‐analyses were found to be moderate.There was no significant difference in quality based on the number of authors and the country of study.A high correlation was found between A Measurement Tool to Assess Systematic Reviews (AMSTAR) and Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) quality assessment scores.AMSTAR and PRISMA are valuable tools that can help the authors to assess and improve the quality of systematic reviews and meta‐analyses.

Comparison of dental maturation in Hong Kong Chinese and United Kingdom Caucasian populations

Understanding dental maturation in ethnically distinct populations is important in forensic age estimations and the presence of population differences in dental maturation was highly debated. No such comparison had been performed between two major populations; Caucasian and Chinese. This study aims to analyze and compare the maturation of permanent teeth from a sample of Caucasian and Chinese populations. Dental panoramic radiographs of subjects aged 2-24years belonging to United Kingdom (UK) Caucasian and Hong Kong (HK) Chinese populations were obtained from a teaching hospital. The teeth were scored and reference datasets were developed separately for males and females. Statistical significance was set at p<0.05 and independent sample t-test was conducted between the average ages at assessment for each stage of development for all the teeth in both groups. The HK Chinese were dentally advanced than the UK Caucasians by an average of 5 months, however, reverse trend was observed in third molars (p<0.05). These findings must be considered whilst utilising population specific reference dataset for dental age estimation.

Effectiveness of ultrasonically activated irrigation on root canal disinfection: a systematic review of in vitro studies

ObjectivesReduction of microbial load from the root canal systems is a pre-requisite for healing of lesions of endodontic origin. Such microbial reduction is influenced by the method of irrigant delivery and activation. The aim of this systematic review was to compare the effect of ultrasonically activated irrigation (UAI) with other irrigation techniques on the reduction of microorganisms during root canal disinfection.Materials and methodsThe research question was created based on the PICO strategy. Two reviewers independently performed a comprehensive literature search in electronic databases. Following application of inclusion and exclusion criteria to the selected articles, a systematic data extraction sheet was constructed. The selected articles were assessed using methodological quality scoring protocol. The risk of bias in selected studies was critically assessed by two reviewers.ResultsA total of 15 articles were included for the systematic review. The included studies were heterogeneous in study design; hence, meta-analysis was not performed. The overall risk of bias for the selected studies was moderate. Overall, UAI showed superior reduction of microbial counts, resulting in better disinfection compared to other irrigation systems chosen for comparison in this review.ConclusionThe use of UAI can bring about superior microbial reduction within the root canal system compared to other irrigant activation techniques.Clinical relevanceActivation of irrigants with ultrasonic brings about significant bacterial reduction from the root canal systems compared to other methods of irrigant activation and conventional syringe irrigation. This might help in improving the outcome of root canal treatment.