Efficacy of different solutions in reestablishing apical patency during nonsurgical endodontic retreatment: An ex vivo study by a senior undergraduate student

Abstract Introduction: This study assessed the effectiveness of different solutions in reestablishing apical patency during nonsurgical endodontic retreatment performed by a senior undergraduate dental student. Materials and Methods: 54 extracted human mandibular premolars with straight canals were prepared and obturated using a gutta-percha cone placed 2 mm short of the working length, ensuring that the apical 2 mm were filled exclusively with AH Plus sealer. After 5 weeks, retreatment was performed using the ProTaper retreatment system. The teeth were randomly assigned to three groups ( n = 18) according to the solution used: 3% sodium hypochlorite (NaOCl – control), orange oil (OOil), and a mixture of methylethylketone (MEK) with tetrachloroethylene (TCE). The data were analyzed using the Kruskal–Wallis and Fisher’s exact tests. Results: Patency was successfully re-established in 100% of the OOil group, 50% of the NaOCl group, and 72.2% of the MEK/TCE group, with the corresponding median times of 36 s, 44 s, and 118 s. No statistically significant differences regarding time were observed between groups. There was a significant association between the groups and the success rate of apical patency reestablishment, with the OOil and MEK/TCE groups showing higher success. Conclusions: Apical patency in straight canals obturated with AH Plus sealer can be more effectively achieved using solvents such as OOil or a MEK/TCE mixture, by a senior undergraduate student.