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Background Human microbiome dysbiosis is related to various human diseases, and identifying robust and consistent biomarkers that apply in different populations is a key challenge. This challenge arises when identifying key microbial markers of childhood caries. Methods We analyzed unstimulated saliva and supragingival plaque samples from children of different ages and sexes, performed 16S rRNA gene sequencing, and sought to identify whether consistent markers exist among subpopulations by using a multivariate linear regression model. Results We found that Acinetobacter and Clostridiales bacterial taxa were associated with caries in plaque and saliva, respectively, while Firmicutes and Clostridia were found in plaque isolated from children of different ages in preschool and school. These identified bacterial markers largely differ between different populations, leaving only Saccharibacteria as a significant caries-associated phylum in children. Saccharibacteria is a newly identified phylum, and our taxonomic assignment database could not be used to identify its specific genus. Conclusion Our data indicated that, in a South China population, oral microbial signatures for dental caries show age and sex differences, but Saccharibacteria might be a consistent signal and worth further investigation, considering the lack of research on this microbe.

Minimally invasive root canal therapy should be defined as a discipline which adhere to a concept of pre⁃serving the healthy tooth structure as much as possible during all the root canal therapy procedure. In the past 15 years, the concept of minimally invasive has spread and developed fast throughout the diagnosis and treatment of endodontics, which made the root canal therapy (RCT) procedure safer, more accurate and efficient. Minimally invasive endodontics rely on the development of various kinds of therapeutic devices and materials, including the 3D image auxiliary equip⁃ ment, operation microscope, the NiTi instrument systems and the disinfection and obturation material. Minimally inva⁃ sive endodontics is a therapeutic concept of the modern root canal therapy which redefined the standard of what a suc⁃ cessful RCT is.

Objective To assess the impact of chronic pharyngitis on oral health related quality of life.Methods Consecutive patients with chronic pharyngitis were recruited. 130 patients and 362 healthy controls were investigated by the questionnaire according to the Chinese version of the oral health impact profile-14 (OHIP-14). Spearman correlation anaylsis and multiple linear regression were performed to analyze the association between OHIP-14 and variables.Results The total OHIP-14 scores of patients with chronic pharyngitis (9.52±7.41) was higher than controls (7.45±7.90), including functional limitations, physical pain subscale, psychological discomfort. Spearman correlation analysis showed that OHIP-14 scores were correlated with age, visual analogue scale (VAS) and the index of decayed-missed-filled teeth (DMFT) (rs=0.238, P=0.01; rs=0.473, P

Background/purpose: Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), as a conventional molecular technique, was utilized to analyze the diversity of oral microbiota. However, studies found that the results of PCR-DGGE were affected by the DNA isolation method. This study compared QIAamp DNA Micro Kit extraction method with the phenol and chloroform extraction method for DNA isolation of saliva of healthy youths and analyzed PCR-DGGE fingerprints. Materials and methods: In the first stage, samples were divided into two after collection from eight health youths. Two methods were used to isolate the DNA for PCR-DGGE analysis. In the second stage, another 16 samples were collected from 14 youths. The better method, QIAamp DNA Micro Kit, was used to isolate the DNA for PCR-DGGE analysis. The cluster analysis was performed with unweighted pair-group method with arithmetic means. Results: The results in the first stage showed that the QIAamp DNA Micro Kit extraction method was more suitable for DNA extraction of saliva than the phenol-chloroform extraction method. In the second stage, the bands were changed into numbers “0”, “1”, and “2” to analyze the similarity of samples according to the bands' lightness. The similarity indices of different periods from the same individual showed that the microbiological composition was very similar (>0.95), while those from different individuals varied greatly (