When direct composite resin was used to restore root filled maxillary first premolar teeth involving a proximal surface, those restored with full-coverage designs had greater fracture resistance.

IntroductionTo help general dentistry residents better manage the intracanal broken instrument situation, we introduced a hands‐on training course into the endodontic curriculum of a general dentistry residency programme.Materials and MethodsThirty general dentistry residents and 30 residents with endodontic specialty training background in a general hospital served as the experimental group and reference group, respectively. The experimental group underwent a training course including a 30‐min lecture and two hands‐on sessions (2 h each). After the course, residents from both groups were asked to perform the instrument removal procedure on simulated root canals. Success rate, procedure time and canal volume change were compared between groups. Questionnaire results were also analysed.ResultsAll residents successfully managed to remove the broken instruments in the test. Procedure time was significantly longer for general dentistry residents (15.8 ± 5.7 min vs 13.7 ± 4.5 min, Mann–Whitney U test, p = .038). Canal volume change was significantly greater for general dentistry residents (8.53 ± 3.82 μl vs 5.94 ± 2.73 μl, independent‐samples t‐test, p = .004). In the questionnaires, trainees gave overall positive ratings for the course. The marginal homogeneity test on before and after scores of the questionnaire items showed the training helped the trainees to reduce the stress level associated with instrument breakage (p < .001). It also motivated the trainees to remove the broken instrument in some straightforward cases (p < .001).ConclusionThe broken instrument removal training course could help the general dentistry residents better manage the intracanal broken instrument situation.