Detection and analysis of comE and luxS genes in quorum sensing signal pathway from Streptococcus oralis / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To detect and analyze two important genes, comE and luxS, in quorum sensing signal pathway from Streptococcus oralis (S. oralis).</p><p><b>METHODS</b>The total genomic DNA of S. oralis NH521 (a clinically isolated strain) was firstly extracted. The comE and luxS genes were then amplified by polymerase chain reaction (PCR) and further sequenced. The obtained sequences were compared with related sequences in GenBank.</p><p><b>RESULTS</b>Target bands of both comE and luxS genes were detected by electrophoresis. The obtained gene sequences were similar to the corresponding sequences from another S. oralis strain (luxS, 95.0%; comE, 99.6%); however, comparing to gene sequences of another species Streptococcus mutans, comE was more divergent (12.7%) than luxS gene (74.1%).</p><p><b>CONCLUSION</b>This study successfully amplified and sequenced comE and luxS genes from S. oralis NH521 strain. The luxS gene accumulated more mutations than comE gene did between two S. oralis strains, but comE gene is more divergent than luxS gene between two Streptococcus species.</p>

A clinical evaluation on accuracy of RayPex5 apex locator for measuring root canal working length / 实用口腔医学杂志

In order to evaluate the accuracy of RayPex5 apex locator in measuring root canal working length in clinical practice and to analyze the possible factor resulting in deviation, the working length of total 211 root canals were measured by handing method and electronic method respectively. The exact working length of those root canals were determined by X-ray method. The accuracy rate of electronic method and handing method was 96.21% and 78.2% respectively, with significant difference(P<0.001). The accuracy rate of front teeth group and molar group measured by electronic method was 100% and 92.5% respectively, with significant difference(P<0.05), while the apical paradentitis group and the apical non-paradentitis group, the front teeth group and the premolar group, and the premolar group and the molar group didn' t differ from each other, respectively. The study showed that the accuracy rate of electronic method was high for determining root canal working length, and Raypex 5 apex locator could define apical seat to measure root canal working length accurately.

The relationship between restoration and furcation involvement on molar teeth / 实用口腔医学杂志

Objective: To investigate the correlation between the presence of a crown (CR) or a proximal restoration (PR) and furcation involvement (FI) on molars. Methods: Data were collected from 237 teeth in 44 patients who had restored and non-restored molars with or without FI.The clinical examinations were conducted on the molars including CR,PR,FI, mobility(MO), endodontic treatment(EN) and probe of periodontal attachment level(PAL). Results: Molars with CR or PR had a significantly highter percentage of FI (P0.05) when compared to molars without restorations. Conclusion: The molars with crowns or restorations involving the proximal tooth surfaces have a highter prevalence of FI and more periodontal attachment lose than molars without restorations.