Introduction: Root canal therapy as a routine dental procedure has resulted in retention of millions of teeth that would otherwise be lost. Unfortunately, successful outcomes are not always achievable within initial endodontic treatments, and that necessitates further treatment. Nonsurgical retreatment is the first choice in most clinical situations. The aim of this clinical pilot study was to assess the effect of additional photodynamic therapy (PDT) on intraradicular bacterial load following retreatment of failed previously root treated teeth. Methods: Thirty single-rooted/canalled endodontically treated matured teeth (in 27 healthy patients) accompanied by apical periodontitis (AP) were selected for this study. Standard protocol was followed for nonsurgical retreatment of each tooth. Microbiological samples were taken after establishment of apical patency, finished cleaning/shaping procedure, and PDT (665 nm, 1 W, 240 seconds). All samples were cultured for 72 hours and colonyforming unit (CFU) was counted. McNemar test was used for statistical analysis of the data. The level of significance was set at 0.001. Results: Routine cleaning and shaping resulted in twenty four negative (80%) out of 30 cultures. Four additional negative results were obtained after additional PDT (93.3%). The addition of PDT to routine procedures significantly enhanced the number of bacteria-free samples (P < 0.001). Conclusion: Regarding elimination of intraradicular microbiota, additional PDT may increase the effectiveness of conventional chemomechanical preparation in previously root filled teeth accompanied by AP. Well controlled randomized clinical trials should be planned for future.

Plasma rich in growth factors scaffold showed no advantage over blood clots regarding healing of the periapical radiolucency, radiographic apical closure and type of the newly formed soft and hard tissues.

Background:The aim of this study was to evaluate apical transportation and centering ability of single-file instruments, WaveOne primary, with full rotation versus reciprocation movement using cone-beam computed tomography (CBCT) analysis in curved mesiobuccal (MB) root canal of human mandibular molars.Materials and Methods:Thirty MB canals of mandibular molars were randomly divided into two groups according to the instrument motion (n = 15): Group 1, reciprocation/WaveOne primary; Group 2, continuous rotation/WaveOne primary. After preparation, the amount of apical transportation and centering ability were assessed by evaluating pre- and post-instrumentation CBCT scans in three section (1, 3, and 5 mm from apical foramen). Statistical analysis of the data was performed using Mann-Whitney U-test and Friedman test (α = 0.05).Results:There was no statistically significant difference between two experimental groups in terms of apical transportation and centering ratio at 1, 3, and 5 mm from apical foramen (P > 0.05).Conclusion:Apical transportation and centering ability of WaveOne primary reciprocating instrument did not significantly differ between two motion patterns.

Long-term success of endodontic treatment is strictly dependent on proper shaping and cleaning of the root canal system followed by obturation of entire prepared space. Anatomical variations should be considered during radiographic and clinical evaluation as parts of endodontic treatment. A mandibular premolar with three canals is quite rare and such a tooth requires special canal preparation and obturation techniques. An astute clinician should identify different canal configurations and treat them endodontically well, because presence of an untreated canal could be a reason for failure of endodontic treatment. This paper describes the conventional orthograde endodontic therapy on an unusual mandibular first premolar with three root canals.