Photodynamic therapy in endodontic root canal treatment significantly increases bacterial clearance, preventing apical periodontitis.

OBJECTIVE: To analyze the antimicrobial activity of photodynamic therapy as an adjunct to conventional endodontic treatment, particularly against Enterococcus faecalis. METHOD AND MATERIALS: A total of 42 single-rooted teeth obtained from 33 patients with apical periodontitis were included. Sampling was developed in three stages: (1) immediately after accessing the root canal, (2) after chemical and mechanical instrumentation, and finally, (3) after photodynamic therapy application. The bacterial load of each sample was quantified by seeding on blood agar plates and selective M-Enterococcus agar. All growing colonies were identified using MALDI-TOF (Bruker; matrix-assisted laser desorption/ionization time-of-flight), and the entire bacterial microbiota composition was determined in the first sample by PCR-DGGE (polymerase chain reaction denaturing gradient gel electrophoresis), using 16 rDNA primers and selective nucleotide sequencing. RESULTS: The endodontic therapy obtained a mean reduction in the cultivable bacterial load of 1.12 log, whereas the photodynamic therapy combination significantly increased the bacterial clearance (P < .0001). Viable cells of E faecalis were detected in 16.6% of root canals, with a mean value of 93 CFU per tooth, which was reduced to 67 and 9 CFU/tooth after conventional endodontic and photodynamic therapy treatments, respectively. Molecular E faecalis detection demonstrated that this species was present in 23.2% of baseline samples. DGGE analysis demonstrated the existence of a more complex microbiota than those observed using classical cultures. CONCLUSION: Photodynamic therapy as an adjunct to root canal treatment produces a significant reduction in E faecalis bacterial load, and it should be considered in the prevention of apical periodontitis.

Determinación del calibre apical posterior al preflaring / No disponible

Objetivo: Calibrar y determinar cuál es el diámetro apical adecuado en función del caso y del tipo de conducto. Para llegar a determinar el diámetro apical adecuado nos propusimos, por un lado, valorar si el preflaring facilita la instrumentación apical, y por otro, verificar si los conductos pueden ser instrumentados a tamaños ISO mayores a los que habitualmente lo son. Material y métodos: Después de realizar una preparación del tercio coronal de 40 conductos mesiales (mv-ml) de 23 molares inferiores exodonciados mediante instrumentación rotatoria, se determinó la longitud de trabajo (LT) tras la cual se llevó a cabo la preparación apical. Para ello, se instrumentó (manualmente) en primer lugar, el conducto a LT-1 mm para eliminar cualquier tipo de interferencia posterior entre las limas y el propio conducto. Una vez finalizado dicho ensanchamiento, se procedió a repermeabilizar el conducto y continuar con la preparación apical a LT (manualmente). Nuestros datos se analizaron estadísticamente por medio del test de ANOVA y t de Student. Resultados: De la muestra estudiada, los datos obtenidos fueron que de un 87,5% de los conductos (35) su diámetro apical se encontraba entre 0,30 y 0,35 mm (30-35 ISO) (15 y 20 conductos respectivamente), el 10% de los conductos (4) tenían un diámetro apical de 0,40 mm (40 ISO) y el 2,5% restante de los conductos (1) se correspondían con un diámetro apical de 0,25 mm (25 ISO). Conclusiones: Se debe tratar de alcanzar un diámetro apical adecuado que nos permite el paso de irrigantes y conseguir así un desbridamiento químico y mécanico del conducto y del periápice, pero sin debilitar en exceso el conducto, De ahí la importancia del ensanche del tercio coronal (preflaring) y del equilibrio de los binomios instrumentación-irrigantes y limpieza-debilitamiento (AU)

Objetive: To calibrate and determine the appropriate apical diameter regarding to the case and the type of root canal. In other to determine the appropriate apical diameter, first of all we set out to assess whether or not the apical instrumentation facilitates preflaring and secondly, to verify if root canal can be instrumented to ISO sizes larger than the ones usually used. Material and Methods: After performing an expansion of the coronal third of 40 mesial root canals (mv-ml) of 23 extracted lower molars done by mechanical instrumentation, we investigated the working length (WL) in which the apical preparation was conducted. To that end, the duct first was implemented (manually) to 1mm above the working length WL) so any further interference between the files and the duct itself would be eliminated. Having completed this enlargement, we continue to working the canal and proceed to the apical preparation to WL (manually). Results. Of the sample studied, data obtained was that 87.5% of the ducts (35) apical diameter was between 0,30 and 0,35 mm (30-35 ISO) (15 and 20 channels respectively), 10% of the ducts (4) had an apical diameter of 0,40 mm the remaining 2.5% of the tubes (1) correspond to apical diameter of 0,25 mm (25 ISO). Conclusions. Proper apical diameter should be obtain in order to let the irrigants flow trough the canal and thereby achieving a chemical and mechanical debridement of the canal and the periapical, but without excessively weaken the canal. That is the reason of the importance of widening the coronal third of the duct (opreflaring) and the balance of the binomial-instrumentation irrigants and cleaning-weakening (AU)