Double Roots of Mandibular Premolar in Full-mouth Periapical Films / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the incidence of two-rooted mandibular premolar morphology using full-mouth periapical film series in a Chinese population, with particular emphasis on bilateral incidence, so as to provide a clinical anatomical basis for root canal treatment in mandibular premolars.</p><p><b>METHODS</b>A total of 2015 patients who underwent dental treatment and had full mouth periapical radiographs at the Peking University School of Stomatology from April 2011 to April 2012 were enrolled in this study. Three experienced dentists reviewed the patients' periapical films and classified the root morphology of mandibular premolars bilaterally. The incidence of unilateral and bilateral double roots were recorded and calculated, including confirmed and suspected bucco-lingual root types.</p><p><b>RESULTS</b>In terms of the morphology of two-rooted mandibular first premolars, of the 2015 cases with complete root formation, two-rooted first premolars were detected in 120 cases, with a total number of 159 teeth. According to the number of teeth, the overall incidence of double roots was 4.03% (159/3972). In terms of the morphology of two-rooted mandibular second premolars, of the 2015 cases with complete root formation, two-rooted second premolars were detected in 24 cases, with a total number of 33 teeth. According to the number of teeth, the overall incidence of double roots was 0.85% (33/3880).</p><p><b>CONCLUSIONS</b>The roots of mandibular premolars display specific morphological patterns. Based on a large sample, we observed and calculated not only the occurrence rate of bucco-lingual and mesio-distal double roots in first and second mandibular premolars, but also the incidence of unilateral or bilateral double roots within the same mandible. These findings could provide useful information on the anatomical structure of mandibular premolars for endodontic, prosthodontic and surgical procedures, and could improve the quality of treatment and reduce complications.</p>

Comparison of periodontal ligament anesthesia and submucosal infiltration anesthesia in healthy volunteers / 中国医学科学院学报

<p><b>OBJECTIVE</b>To compare periodontal ligament anesthesia using a computer-controlled local anesthetic delivery system (C-CLADS) and submucosal infiltration anesthesia using a manually operated syringe in terms of the injection pain, anesthetic effect, anesthetic dose, and complications in healthy volunteers.</p><p><b>METHODS</b>Fifty healthy volunteers, aged 18 to 56 years, were recruited from September 2012 to May 2013 in the Department of Stomatology of Peking Union Medical College Hospital. A randomized self-controlled trial was conducted by applying a periodontal ligament anesthesia on one side and conventional manual submucosal infiltration anesthesia to the other (control) side. The differences in the onset time of anesthesia, drug dosage, anesthetic effect, and the degree of injection pain were compared. The complications associated with the two anesthesia methods were also recorded.</p><p><b>RESULTS</b>When using C-CLADS to perform a periodontal ligament anesthesia, the drug dosage and the severity of injection pain were significantly less than those of conventional manual infiltration anesthesia [drug dosage: (0.34±0.09)ml vs.(0.55±0.13)ml, P<0.01; VRS: 0.42±0.73 vs. 1.38±0.92, P<0.01; VAS: 1.34±1.21 vs. 3.10±1.70, P<0.01]. The anesthesia success rate was approximately 90.0%, showing no significant difference relative to conventional submucosal infiltration anesthesia. Approximately 24% of the volunteers experienced postoperative pain after periodontal ligament anesthesia.</p><p><b>CONCLUSION</b>Compared with conventional submucosal infiltration anesthesia using manual syringes, periodontal ligament anesthesia performed using C-CLADS can reduce the injection pain and drug dosage while achieving a satisfactory anesthetic effect; however, a considerable proportion of cases may experience postoperative pain.</p>