Root-Canal Filling Quality after Manual vs. Rotary Treatment by Students

Root-canal treatment by using nickel-titanium files is getting more and more popular. Teaching rotary and reciprocating instrument systems is an inherent part in today´s universities curricula. The aim of this retrospective study was to evaluate the root-canal filling quality by radiographic criteria depending on the type of root-canal treatment in a clinical student course.

Method:

202 randomly selected root-canal filling cases (incisivi, premolars and molars) were selected in the Integrated Clinical Course of Witten/Herdecke University between 2010 and 2012. 101 cases each were treated with stainless-steel instruments (group A) in step-back technique or with Mtwo nickel-titanium (Ni-Ti) files (VDW, Munich, Germany) in torque controlled rotary motion (group B). X-rays were used by two calibrated examiners for obturation quality assessment according to Santos et al. (Braz Dent J.2010;21(4):315-21): Quality parameter were homogeneity, apical extension, and taper resulting in a total score (1: perfect, 2: satisfactory, 3: deficient). Statistical analysis was performed by Pearson´s chi-squared test at a significance level of 95%.

Result:

The incisivi group showed no statistical differences concerning obturation quality between manual or rotary root canal preparation (p>0.05, score 1 A: 7.7%, B:30.8%; score 2 A:30.8%, B:23.1%; score 3 group A 61.5%, group B 46.2%). Significant differences in obturation quality could be found in the premolar group (p<0.05, score 1 A: 4.4%,B: 15.6%; score 2 A: 20%, B:33.3%; score 3 A: 75.6%, B: 51.1%) as well as in the molar group (p<0.05, score 1 A: 0%, B: 6.7%; score 2 A: 0%, B:36.7%; score 3 A: 100%, B 56.7%).

Conclusion:

When performed in a dental student course, root-canal treatment by using machine driven Ni-Ti files improves the obturation quality in complex anatomies when compared to conventional manual preparation by stainless-steel instruments.