Clinical Investigation of Chemomechanical Parameters for an Efficient Disinfection of the Root Canal

The aim of the study is first, to evaluate the clinical antibacterial efficacy of two different NaOCl concentrations (2,5% and 5%) under a predefined irrigant flow rate in teeth with pulp necrosis and apical periodontitis by using Real-time PCR. . Second, to evaluate the efficacy of final irrigation by assessing, if possible, a numerical definition for that "so called" as "copious irrigation".

Besides the total microbial load, the antibacterial efficacy of final irrigation procedure against two different bacterial species (namely Pseudoramibacter alactolyticus and Treponema denticola) will also be examined.

The antibacterial efficacy of two different NaOCl concentrations (2,5% and 5%) under a predefined irrigant flow rate in teeth with pulp necrosis and apical periodontitis will be examined through the calculation of the total bacterial load before any treatment procedure and the possible bacteria reduction after each treatment procedure (chemomechanical preparation, and final irrigation treatments). In addition, the antimicrobial efficacy of the above two different concentrations of NaOCl will be compared in terms of treatment outcome. All patients will be asked for one-year recall examination where the outcome of endodontic treatment will be evaluated through clinical and radiographic examination. For the identification of the"copious irrigation" the total amount of final irrigation will be divided in two equal parts of volume/ time (15ml for 5 minutes each). Total bacterial load that will remain after chemomechanical preparation will be compared to the number of bacteria calculated after the first and the second part of irrigation. It will be investigated if final irrigation provides to further microbial reduction and whether prolonged irrigation augments the antibacterial effect.

Besides the total microbial load, the antibacterial efficacy of final irrigation procedure against two different bacterial species (namely Pseudoramibacter alactolyticus and Treponema denticola) will also be examined. First, the prevalence of these specific species will be investigated in primary endodontic infections in Greek-living population. In addition, the effect of chemomechanical preparation and final irrigation procedure on the number of these species will be relatively examined though the reduction curves that will be obtained by qPCR.

Eligibility Criteria:
Inclusion Criteria:

* Informed consent by the patients who wish to participate in the study.
* Single-rooted teeth with pulp necrosis confirmed by pulp sensibility tests, negative response to both cold and electric pulp testing and radiographic evidence of apical periodontitis.
* Teeth with relatively straight canals, complete root development and no pulp canal obliteration.

Exclusion Criteria:

* Patients who have received antibiotic treatment the last 3 months or need chemoprophylaxis for dental treatment.
* Teeth with previous endodontic treatment.
* Teeth with cracks or incomplete vertical root fracture which disturbs the integrity of the pulp chamber walls.
* Teeth with periodontal pocket more than 4mm.