Papillae alterations around single-implant restorations in the anterior maxillae: thick versus thin mucosa / 国际口腔科学杂志·英文版

To evaluate the papilla alterations around single-implant restorations in the anterior maxillae after crown attachment and to study the influence of soft tissue thickness on the papilla fill alteration. According to the inclusion criteria, 32 patients subjected to implant-supported single-tooth restorations in anterior maxillae were included. The patients were assigned to two groups according to the mucosal thickness: (i) group 1, 1.5 mm s mucosal thickness 3 mm; and (ii) group 2, 3 mm<mucosal thickness 4.5 mm.Assessments of interproximal papillae at the time of crown placement (baseline) and at 6-month post loading (follow-up) were made by two prosthodontists using papilla fill index (PFI). The mean mucosal thickness was (2.49±_0.31) mm (group 1) and (3.81±_0.31) mm(group 2) for the two groups respectively. A significant difference in PFI between the groups was detected at the baseline (P<0.001).PFI improvements over time occurred after 6-month follow-up irrespective of the groups. When compared to group 1, the likelihood to obtain papilla fill was significantly higher for group 2 with an odds ratio of 6.05 (P<0.001). The interproximal papilla level around single-implant restorations could improve significantly over time after 6-month restoration according to PFI assessment. The thicker mucosa before implant placement implied a more favorable esthetic outcome in papilla alteration.

Comparison on the shaping ability of three different instruments in preparing curved molar canals / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the changes of root canal curvatures and apical transportation index when the curved root canals were prepared by hand-use ProTaper, stainless steel K-files or nickel-titanium K-files.</p><p><b>METHODS</b>Forty-five extracted molars, with the degree of root canal curvature from twenty to forty, were divided into fifteen sections in curvature sequence. After that, three canals of each section were randomly distributed to three different instrumentation groups. One group of them was prepared by hand-use ProTaper with crown-down technique. The other two groups were instrumented by stainless steel or nickel titanium K-files with modified step-back technique to working length. The standard digital radiographs were taken to record the profiles of root canals and the positions of the tips of the instruments. The change of curvature degree between pre- and post-instrumentation and the apical transportation indexes (ATI) among three groups were analyzed respectively using SAS statistical software.</p><p><b>RESULTS</b>The change of curvature degree between pre- and post-instumentation for stainless steel K-files group was largest, and the ATI of stainless steel K-files group was significantly greater than that for nickel titanium K-files group (P < 0.05). The canals prepared by hand-use ProTaper was smallest in the change of curvature and ATI among the three groups (P < 0.01).</p><p><b>CONCLUSION</b>When preparing curved molar canals, hand-use ProTaper with crown down technique can obtain better shaping effect and higher efficiency.</p>