Effects of TCP/HA-coating titanium on the adhesion behavior of human gingival fibroblasts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate effects of hydroxyapatite (HA) and porous tricalcium phosphate/hydroxyapatite (TCP/HA)-coating titanium on the adhesion behavior of human gingival fibroblasts (HGFs).</p><p><b>METHODS</b>Coatings of HA and duplex phases TCP/HA on titanium (Ti) were formed by ion beam assisted deposition (IBAD) method. Attachment, spreading, extracellular matrix (ECM) production, and focal adhesion plaque formation of HGFs were investigated on commercially pure (CP) titanium, HA-coated CP titanium and porous TCP/HA-coated CP titanium. After incubation of HGFs on these substrates, the number of attached cell, the area of cell spreading, immunostained ECM including fibronectin (FN) and type I collage, and vinculin (presenting the formation of focal adhesion plaque) were quantified by morphometric analysis using immunofluorescence microscope.</p><p><b>RESULTS</b>TCP/HA and HA coatings exhibited that the attached cell number and cell spreading area were greater than those of CP titanium (P < 0.05), and the formation of focal adhesion plaque was earlier than that of uncoated substrate (P < 0.05). The number of attached cell and the formation of type I collagen on TCP/HA were more than those on Ti and HA. After 24-hour incubation on TCP/HA surface, the number of attached cell was 198.1 +/- 27.7 and the fluorescent intensity of type I collagen was 154.10 +/- 31.56. While under the same condition, the corresponding numbers for the CP titanium were 125.1 +/- 29.9 and 132.63 +/- 35.26. The differences between the two groups were significant (P < 0.05).</p><p><b>CONCLUSIONS</b>In this study, the porous TCP/HA coating significantly facilitated the adherence of human gingival fibroblasts to Ti surface and could improve the biocompatibility of titanium.</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>