Comparative study of resosolv and chloroform in retreatment of canal obturated with resinifying agent / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the possibility for removal of resinifying agent, time required for removal and the working length loss by Resosolv or Chloroform.</p><p><b>METHODS</b>40 human teeth (80 root canals) obturated with FR phenolaldehyde agent were divided into four groups, 20 root canals per group. Group A: Resosolv with K file; group B: chloroform with K file; group C: Resosolv with Ultrasonic K file; group D: Chloroform with ultrasonic K file. Calculating the pereentage for removal of resinifying agent, time required for removal and the working length loss.</p><p><b>RESULTS</b>The effectiveness of Resosolv for removing resinifying agent was better than chloroform. 87.5% of canals could be negotiated by Resosolv; 45% of canals be negotiated by chloroform.</p><p><b>CONCLUSION</b>Resosolv is an effective solvent for canals obturated with resinifying agent.</p>

Location and negotiation of second mesiobuccal canals in maxillary molars / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate prevalence, location, negotiation and the effect of operating microscope (OM) in the treatment of the second mesiobuccal canal (MB2) in maxillary molars.</p><p><b>METHODS</b>113 maxillary molars were studied. The crowns of the teeth were removed 1 mm above the chamber bottom for searching MB2 canal. Initially location and negotiation of MB2 canal were attempted without OM. Teeth in which MB2 canal were not located or negotiated were further explored under OM. Canal orifices including MB orifice, MB2 orifice and palatal orifice were filled by red gutta-percha cones, then the teeth were scanned by scanner. The images were analyzed by Image-Proplus 4.0 software to measure the relationship between MB2 canal and other canals.</p><p><b>RESULTS</b>The MB-MB2 distance is (1.47 +/- 0.54) mm, MB-P distance is (5.77 +/- 0.66) mm, the vertical distance from MB2 to MB-P line is (0.53 +/- 0.28) mm, the angle between MB-P line and MB-MB2 line is 23.07 degrees +/- 13.08 degrees. MB2 orifices were located in 70 teeth (61.9%) and negotiated in 53 teeth (46.9%) without OM. With OM, additional MB2 orifices were located in other 6 teeth, 4 were negotiated; and 2 were negotiated in which MB2 canal were not negotiated without OM.</p><p><b>CONCLUSIONS</b>MB2 canal can be located in 67.3% and negotiated in 52.2% of maxillary molars. Ability to locate and negotiate MB2 canal is facilitated by OM. The MB2 canal was located less than 1 mm mesially to the MB-P line and 2 mm palatally from the MB orifice.</p>