• Phonphanit Sivavetpikul, D.D.S.
• Kessiri Wisithphrom, D.D.S., Ph.D.
• Peraya Puapichartdumrong, D.D.S., Grad. Dip. Clin., Ph.D.

Background/Objectives: The objectives of this study were to evaluate the success and failure rates
as well as factors influencing the outcome of initial endodontic treatment performed by dental students
at the Faculty of Dentistry, Naresuan University, Thailand, from 2010 to 2015.

Materials and Methods: Data from the treatment records, clinical signs and symptoms, and
radiographic records of 213 endodontically treated anterior teeth and premolar were collected and
evaluated. Digital periapical radiographs obtained at pre-operation and the last follow-up period were
interpreted independently by two examiners via Periapical index (PAI) score. Treatment outcome was
evaluated as success or failure based on clinical signs and symptoms as well as radiographic criteria.
Factors influencing the treatment outcome were analyzed using Chi-square test and logistic regression
model.

Results: The results showed that the recall rate was 36.3%, ranging from 6 to 64 months, with a mean
of 18 months. The overall success rate was 72.8%, the failure rate was 27.2%, and the functional rate
was 96.2%. The multivariate analysis identified 2 significant (p ≤ 0.05) influencing factors: the presence
of pre-operative periapical lesion size ≥ 5 mm and the recall period at 24-35 months, with odds ratio
of 0.21 and 3.18, respectively.

Conclusions: The overall endodontic success rate was 72.8%, and failure rate was 27.2%. The success
of treatment was significantly influenced by the presence of pre-operative periapical lesion and the
recall period.

(CU Dent J. 2019;42:39-52)