Detection of the unknown components of the oral microflora of teeth with periapical radiolucencies in a Turkish population using next-generation sequencing techniques.

AIM: To detect the unknown components of the oral microbiome and the effects of root canal treatment in a Turkish population and to evaluate the changes in microbial diversity in the root canals before and after treatment. METHODOLOGY: Single-rooted central and lateral maxillary incisors with one canal were chosen from 20 patients. Baseline samples of intact intracanal microbiota were collected from 20 root canals of permanent teeth with necrotic pulps using sterile paper points. After root canal preparation, the root canals were filled with a calcium hydroxide paste for 7 days. Calcium hydroxide was removed from root canal with 2.5% sodium hypochlorite and 17% EDTA using passive ultrasonic irrigation (PUI). A second bacteriologic samples were taken with sterile paper points prior to root filling. The samples were processes with DNase-I treatment using next-generation sequencing (NGS). Reduction in bacterial numbers during root canal treatment was evaluated using real-time quantitative PCR (qPCR). All statistical analyses were conducted using the MINITAB 17 software (Minitab Ltd. Co., Coventry, UK). A one-sample t-test was used to analyse the data. Statistical significance was accepted at P < 0.05. RESULTS: Relative abundances of Mycoplasma sp., Paludibacter sp., Tannerella sp., Prevotella spp. and an uncultured species from the order Bacteroidales decreased with root canal preparation and medication (98.7%, 99.8%, 98.8%, 97.7% and 99.3%, respectively), whilst the relative abundances of Methylobacterium sp., Corynebacterium sp. and Streptococcus infantis increased (93.1%, 94.8% and 99.4%, respectively). Considerable numbers of Streptophyta species were detected before and after treatment. The ratio of Agrobacterium sp. in the treated teeth community and the ratio of order Streptophyta in the infected canals had negative correlations with the success of bacterial elimination. CONCLUSIONS: The combination of NGS and qPCR techniques resulted in detection of previously unknown components of the oral microbiome and the effects of root canal treatment on their relative abundance in a Turkish population.

Comparison of intracoronal bleaching methods on teeth discolored by different antibiotic pastes.

AIM: To compare the bleaching efficacy of sodium perborate with different activation methods on crowns discolored by two different antibiotic pastes. MATERIALS AND METHODS: Eighty-five extracted human incisors were prepared to size #30 using ProTaper rotary instruments. After chemomechanical preparation and irrigation procedures, the specimens received triple antibiotic paste (TAP, n = 40), minocycline paste (MP, n = 40), or calcium hydroxide (n = 5, control group) and coronally sealed with temporary filling material. Spectrophotometric readings were obtained on day 0-week 4. Data were analyzed with the Mann-Whitney U-test and Wilcoxon sign test (P < 0.05). Sodium perborate was then inserted into the pulp chambers of discolored teeth (four subgroups, n = 10) and activated by heat or ultrasonically using two different frequencies and times. Spectrophotometric readings were obtained on days 3-7. Data were analyzed by the Mann-Whitney U-test and Kruskal-Wallis test (P > 0.05). RESULTS: Both groups showed statistically significant coronal discoloration at each time interval (P < 0.01), but their final shades did not significantly differ between the groups (P > 0.05). Although the MP subgroups exhibited more bleaching than the TAP subgroups on days 3 and 7, the difference was not significant (P > 0.05). The bleaching results for the sodium perborate activation techniques did not significantly differ among groups (P > 0.05). CONCLUSIONS: Both antibiotic pastes induced crown discoloration that was reversible using all sodium perborate bleaching techniques.

Assessment of the periapical health of abutment teeth: A retrospective radiological study.

AIM: The aim was to examine the technical quality of root fillings and periapical status of root-filled and nonroot-filled teeth restored with crowns and bridge retainers through a retrospective analysis of orthopantomographs (OPTGs) in an adult Turkish subpopulation. MATERIALS AND METHODS: In this study, the digital OPTGs of adult patients between the ages of 20 and 70 who appealed to the Endodontics Endodontics Department of the Dentistry Faculty at Marmara University (Istanbul, Turkey) for the first time to have their endodontic treatment needs met were used. The periapical health of all teeth restored with crowns and bridge retainers, and the technical quality of the root fillings on abutment teeth were evaluated by radiographic criteria. RESULTS: The survey was carried out using the OPTGs of 1000 adult patients composed of 590 (59.0%) women and 410 (41.0%) men. 4656 (20.9%) of the totally examined 22280 teeth were with crowns and bridge retainers. 986 of the total abutment teeth were root-filled and 458 (46.5%) of them had apical periodontitis (AP) while 3670 of the total abutment teeth were nonroot-filled and 930 (25.3%) of them were with AP. The most commonly treated teeth were premolars (33.8%), followed by molars (26.2%), incisors (23.3%) and canines (16.7%). Technical quality was proved to be adequate in 27.5% of the root fillings. A higher frequency of AP was related to inadequate root fillings (P<0.01). CONCLUSION: The frequency of root-filled abutment teeth with AP, nonroot-filled abutment teeth with AP, and technically inadequate root-fillings among teeth with crowns and bridge retainers was high in the selected adult population.