Apical Negative Pressure irrigation presents tissue compatibility in immature teeth

Quaternary ammonium silane, calcium and phosphorus-loaded PLGA submicron particles against Enterococcus faecalis infection of teeth: An in vitro and in vivo study

Refractory root canal infection of human teeth is the primary cause of dental treatment failure. Enterococcus faecalis is the major cause of refractory root canal infection. In the present study, poly(D,L-lactic-co-glycolide) (PLGA) submicron particles were used as carriers to deliver an antimicrobial quaternary ammonium silane (code-named K21) as well as calcium and phosphorus elements. The release profiles, antibacterial ability against E. faecalis, extent of infiltration into dentinal tubules, biocompatibility and in vitro mineralization potential of the particles were investigated. In addition, the antimicrobial effects of the particles against E. faecalis infection were evaluated in vivo in the teeth of beagle dogs. The encapsulated components were released from the PLGA particles in a sustained-release manner. The particles also displayed good biocompatibility, in vitro mineralization ability and antibacterial activity against E. faecalis. The particles could be driven into dentinal tubules of dentin slices by ultrasonic activation and inhibited E. faecalis colonization. In the root canals of beagle dogs, PLGA submicron particles loaded with K21, calcium and phosphorus demonstrated strong preventive effects against E. faecalis infection. The system may be developed into a new intracanal disinfectant for root canal treatment.

Negative Pressure Irrigation Presents Mineralizing Potential in Dogs' Immature Teeth with Periapical Lesion

The objective of this in vivo study was to assess the effect of the root canal irrigation by negative and positive apical pressure on the expression of molecules that are an indicative of cell differentiation with mineralizing phenotype in teeth of dogs with incomplete rhizogenesis and induced periapical lesion. A total of 30 teeth (60 roots) were distributed into 3 groups (n=20): EndoVac®, Conventional and Control. After 90 days, the routine histotechnical procedures were performed and the sections were submitted to immunohistochemical technique for the staining of osteopontin (OPN), alkaline phosphatase (ALP) and the RUNX2 transcription factor in the apical and periapical regions of the roots. A semi-quantitative analysis of the positive immunostaining was performed and the intensity of the expression was classified in absent (0), mild (1), moderate (2), or intense (3). Scores data were statistically analyzed by the Kruskal-Wallis non-parametric test and Dunn post-test, and the significance level was set at 5%. RUNX2 immunostaining revealed that in the negative pressure group there was a significantly stronger (p<0.05) immunostaining in comparison to the control group. Regarding the OPN expression, it was not possible to detect a statistically significant difference between the groups (p>0.05). After analyzing ALP immunostaining, a statistically significant difference was observed between the groups (p<0.05), and the negative pressure group showed a markedly stronger mark immunostaining than the control group. The results of the present in vivo study allowed concluding that negative apical pressure irrigation presents mineralizing potential in immature teeth with apical periodontitis.

Radiographic and Immunohistochemical Evaluation of Root Canal Treatment Using Different Irrigation Systems

The aim of this study was to evaluate the radiographic periapical repair and the synthesis of inflammatory mediators after endodontic treatment in a single session, using different irrigation protocols, in teeth with apical periodontitis. Experimental apical periodontitis were induced in dog's teeth randomly assigned into 4 groups: G1 - Irrigation by Negative Apical Pressure (n= 20); G2 - Passive Ultrasonic Irrigation (n= 20), G3 - Positive Pressure Irrigation (n= 20); G4 - apical periodontitis without treatment (n= 20). After 180 days, the animals were euthanized, the tissues removed and submitted to histotechnical processing for immunohistochemical analysis of osteopontin (OPN), tumor necrosis factor-a (TNF-a) and interleukin 1-a (IL-1a). Radiographic analysis was performed using the Periapical Index (PAI), obtained prior to and 180 days following endodontic treatment. Data were analyzed using Wilcoxon signed-rank test, Fisher's Exact test or Kruskal-Wallis test and Dunn's post-test (a = 5%). Radiographically, after endodontic treatment, apical periodontitis persisted in 35% of G1 specimens, 40% of G2 and 40% of G3 (p>0.05), although a PAI reduction was observed (p<0.05). By immunohistochemical evaluation, endodontic treatment resulted in lower synthesis of TNF-a and OPN in periapical region, compared to apical periodontitis without treatment (p<0.05). Production of IL-1 was not modulated by endodontic treatment (p>0.05). Periapical healing was observed in approximately 60% of the cases after endodontic treatment performed in a single session with lower synthesis of TNF-a and OPN in the periapical region, regardless of the irrigation protocol used.