Objective: To evaluate the outcome of initial endodontic treatments performed by undergraduate students in a Greek dental school and to determine the factors that may impact the treatment outcome.
Methods: From a randomly selected sample of 677 non-surgical endodontic treatments performed between 2012 and 2015, follow-up appointments were scheduled with patients whose dental records matched the inclusion criteria. After clinical and radiographic examination, the treatment outcome was classified as success (healed/healing) or failure (uncertain/unsatisfactory healing). The statistical analysis of the data was performed using generalized estimating equations. Intra-examiner and inter-examiner agreements were checked with the intraclass correlation coefficient and with Cohens kappa. The statistical significance level was set at p<0.05.
Results: A total of 244 teeth (349 roots) were included for further analysis, and the mean follow-up period was 2.8 years. Overall, the success rate for the treated roots was 72.8%. Μultivariate analysis revealed four decisive factors as having a positive impact on the outcome, namely, the absence of voids within the root fillings (p<0.001), the absence of pre-operative periapical lesions (p=0.001), the extension of the root filling material by 0-2 mm from the radiographic apex (p<0.001) and the root type (anterior roots: p=0.015 and premolar roots: p=0.011). The association of gender, arch, pulp status and type of coronal restoration with the outcome was not statistically significant (p>0.05). Moreover, when the outcome according to pre-operative periapical status and the technical variables of root fillings (apical extension and density) was investigated, roots without periapical lesion, with a root filling material extended 0-2 mm within the apex and without voids revealed the highest success rate (94.5%).
Conclusion: The success rate of non-surgical endodontic treatments performed in a Greek dental school was in the range of those reported in other studies. The pre-operative periapical status, technical variables of root fillings (apical extension and density) and root type were regarded as significant prognostic factors of the outcome.