Factors Affecting the Outcome of Non-Surgical Endodontic Treatments Performed by Undergraduate Students in a Greek Dental School

Abstract

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 Cohen's 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.

A Clinical Audit on the Follow-up Rate and Endodontic Outcome of Root Canal Therapy Performed by Dental Undergraduates

“…Even though the current study showed statistically insignificant correlation between technical quality and endodontic outcome, the apical extension of root canal fillings within 2 mm from the radiographic apex was found associated with the highest success rate of endodontic outcome (67.5%), which is consistent with other studies [21,25,27,[34][35][36]. The present study also reported highest failure rates in unacceptable apical extension of obturation (40%) as compared to presence of void (21.4%) and endodontic mishaps (24.1%).…”

“…Dental undergraduates in the current study achieved an endodontic success rate of 66.7% after an average of 2.8 years follow-up, which was lower as compared to the dental undergraduates in other countries [20][21][22][23] and similar to Ng et al [19]. In UK, Heling and Tamshe [20] reported an overall success rate of 70% in 213 teeth that were treated by dental undergraduates.…”

“…A study evaluating 1,372 periapical radiographs of root treated teeth also displayed that teeth with poor root canal filling had higher apical periodontitis prevalence (66.3%) than those with adequate root canal filling (16.5%) [26] . According to Polyzos et al [21], the success rate for root canal with and without voids were 45.9% and 83.3% respectively (p<0.001). These results are in agreement with the study done by Tronstad et al [30], whereby they demonstrated that the factor of utmost importance for periapical health status is the technical quality of RCT.…”

“…In UK, Heling and Tamshe [20] reported an overall success rate of 70% in 213 teeth that were treated by dental undergraduates. Greek [21] and Brazil [22] dental schools showed a success rate of 72.8% and 75.5% respectively in their follow-up three years after the completion of RCT. Smith et al [24] demonstrated an overall success rate of 84% in 821 teeth that had root fillings placed by postgraduate students and staff in a dental hospital while Barbakow et al [25] revealed 87% success rate in RCT performed in a general practice.…”

“…In line with the present study, Heling et al [34] also observed that the apical limit of root canal obturation affects the success rate of RCT and higher failure rates was shown in those root canals obturated beyond the apex. In terms of extension of root canal filling, another study demonstrated that success rate of root filling extended by 0-2 mm from the radiographic apex (86.9%) was significantly higher (p<0.001) than those under-filled or overfilled roots (58.4%) [21].…”