Evaluation of a broken instrument removal training course for general dentistry residents.

INTRODUCTION: To 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 METHODS: Thirty 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. RESULTS: All 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). CONCLUSION: The broken instrument removal training course could help the general dentistry residents better manage the intracanal broken instrument situation.

[In vitro study of a new lasso device for intra-canal broken instrument removal].

PURPOSE: This in vitro study was aimed to evaluate the efficacy of intra-canal broken instrument removal using a new lasso device. METHODS: Mandibular molars that were freshly extracted within 6 months were used in this study. The teeth were examined under magnification to rule out cracks. Only teeth with closed apices and measured longer than 18 mm from cusp tip to root tip were chosen. Root curvature should be less than 90°. After root canal negotiation, 3 mm of a size 30#04 taper nickel titanium file, which was shortened by 5 mm before, was intentionally fractured in the coronal to mid-third of the mesial buccal canal. The teeth were randomly assigned to the lasso and ultrasonic group, each group had 20 teeth. All teeth underwent broken instrument removal procedures. The procedure time and removal success rate were recorded. Cone-beam CT(CBCT) was taken before and after instrument breakage, and after instrument removal. Root curvature, depth of fracture, level of broken instrument, and canal volume were recorded for each group. Statistical analysis was performed using SPSS 13.0 software package. RESULTS: There was no significant difference in terms of root curvature, depth of fracture, level of broken instrument and removal success rate between the two groups(P＞0.05). The procedure time was significantly shorter and root canal volume increase was significantly less in the lasso group(P＜0.01). CONCLUSIONS: The new lasso device for intra-canal broken instrument removal has a high success rate in this in vitro study. Its usage can preserve more root dentine and shorten treatment time. It can be an useful adjunct to ultrasonic instrument in removing broken instrument from the root canal.

[Root canal treatment of two-rooted three-canal maxillary first premolar: a case report].

According to literature, the incidence of three-canal maxillary first premolar is between 0.5% and 7.5%. The two types of three-canal maxillary premolars are two-rooted and three-rooted three-canal maxillary premolars. Most case reports in Chinese literature focus on three-rooted three-canal maxillary premolars. To our knowledge, no domestic case report on two-rooted three-canal maxillary premolar has been published. In this study, we describe the root canal treatment of a two-rooted three-canal maxillary premolar.

[The clinical study on the use of diode laser irradiation in the treatment of periodontal-endodontic combined lesions].

OBJECTIVE: To evaluate the adjunctive effect of diode laser irradiation for the treatment of periodontal-endodontic combined lesions. METHODS: 30 cases with periodontal-endodontic combined lesions were selected. All cases were randomly divided into experimental group and control group (n=15). In the control group, patients were treated with root canal therapy and conservative periodontal treatment (scaling and root planning), and patients in the experimental group were treated with root canal therapy and conservative periodontal treatment followed by diode laser irradiation. Clinical measurements including pocket probing depth (PPD), clinical attachment level (CAL), modified bleeding index (mBI), periapical index (PAI) were taken before treatment (baseline). Three and six months after the treatment, the adjunctive effects of diode laser in the treatment of periodontal-endodontic combined lesions were evaluated. RESULTS: Three months after the treatment, the average PPD, CAL and mBI levels were reduced significantly in both groups. But the average PPD reduction in the experimental group was significantly greater (P<0.05) than in control group. However the average CAL and mBI reduction were not significantly different between two groups. Six months after the treatment, the average PPD, CAL and mBI levels were further reduced in the experiment group, but not in the control group. The average PAI levels were reduced significantly in both groups, but the PAI reduction was not significantly different between two groups. CONCLUSION: The use of diode laser as an adjunct procedure in the treatment of periodontal-endodontic combined lesions can aid in achieving success.