All-ceramic premolar guiding plate retains resin-bonded fixed partial dentures / 华西口腔医学杂志

OBJECTIVE@#This study aims to investigate the fracture resistance and short-term restorative effects of resin-bonded fixed partial dentures (RBFPDs) made from heat-pressed lithium-disilicate-based glass-ceramic (IPS e.max press) and zirconia ceramic (WIELAND) and retained by all-ceramic guiding plates when used to restore missing mandibular second premolars.@*METHODS@#A total of 64 human mandibular first premolars and first molars were prepared as abutments, then were randomly divided into 4 groups (n=8): E0, heat-pressed ceramic RBFPDs, no cyclic loading; E1, heat-pressed ceramic RBFPDs exposed to 300 000 cycles of dynamic loading; W0, zirconia ceramic RBFPDs, no cyclic loading; and W1, zirconia ceramic RBFPDs exposed to 300 000 cycles of dynamic loading. Fracture strength was tested in a universal testing machine.@*RESULTS@#The medians of fracture strength were 1 242.85 N±260.11 N (E0), 1 650.85 N±206.77 N (W0), 1 062.60 N±179.98 N (E1), and 1 167.61 N±265.50 N (W1). Statistical analysis showed that all the groups exhibited significantly higher fracture strength compared with the maximum bite force in the premolar region (360 N; P0.05). Significant statistical differences were found between the zirconia ceramic groups (W0 and W1, P0.05) after dynamic loading.@*CONCLUSIONS@#The RBFPDs retained by all-ceramic guiding plates exhibited promising fracture properties and optimal short-term restorative effects when used to restore missing mandibular second premolars.

The acceleration of titanium implant osseointegration by low intensity pulsed ultrasound: an experimental study in rats / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To establish an animal model of titanium implant and to investigate the effects of low intensity pulsed ultrasound (LIPUS) on the implant osseointegration.</p><p><b>METHODS</b>Twenty-four female Sprague Dawley (SD) rats were used. Titanium implants were inserted into tibia metaphysis bilaterally in each SD rat. Since the second day following implant surgery, LIPUS stimulation were carried out around the implant on the right side for 20 minutes per day, and implants on the left side remain untouched as self-control. Eight rats were sacrificed and tibiae specimens were harvested on the end of the 4th, 8th, and 12th week respectively. X-ray picture, micro-CT analysis and histological sections were performed to evaluate the effects of LIPUS on the implant osseointegration.</p><p><b>RESULTS</b>Osseointegration at the interface between the implant and bone tissue was observed bilaterally. In the micro-CT histomorphometry analysis, the percentage of osseointegration (%OI) of experiment side were (45.708 ± 3.316)%, (46.231 ± 1.954)%, and (46.807 ± 1.451)% on the end of the 4th, 8th, and 12th week. Meanwhile, the %OI of control side were (43.021 ± 3.558)%, (44.272 ± 3.023)%, and (44.894 ± 4.215)% respectively. The %OI on the 4th weekend, bone volume ratio (BV/TV) on the 4th and 8th weekend, trabecular thickness (Tb. Th) and degree of anisotropy (DA) on the 8th and 12th weekend of the experiment side tibia were significantly greater than those on the control side (P < 0.05). The histological examination showed that the thickness of new bone around the implant and the bone-implant contact area was obviously greater in the LIPUS treated side compared to the control side.</p><p><b>CONCLUSIONS</b>The LIPUS therapy may accelerate the bone healing and osseointegration at the interface between titanium implant and bone, and promote remodeling of bone trabecula on the early stage.</p>

A clinical study of immediate dental implant and immediate restoration / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the clinical results of immediate implant and immediate restoration and to discuss the applying principles of these techniques.</p><p><b>METHODS</b>Fourteen cases underwent immediate implant surgery for 37 dental implants immediately after the teeth or roots were extracted. Among them, 6 cases (14 implants) received immediate restoration after implant placement. The second stage operation and final restoration were performed 4 months on average postoperatively, and the mean follow-up time was 22 months.</p><p><b>RESULTS</b>Two implants from 1 case were lost at 3 weeks after immediate implant and immediate restoration. The rest cases achieved good clinical results. Accumulative 4-year survival rate was 94.6%.</p><p><b>CONCLUSIONS</b>The result of immediate implant and immediate restoration is predictable if the cases are properly selected.</p>