Maxillary sinus floor augmentation with Bio-Oss as a sole graft: a histologic, radiographic and preliminary clinical study / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate new bone formation and preliminary clinical outcomes following maxillary sinus floor augmentation with Bio-Oss alone.</p><p><b>METHODS</b>Nine patients were treated with ten maxillary sinus floor augmentations using Bio-Oss alone, and eighteen Straumann implants were placed. After five to eleven-month healing period at implant placement, cylindrical specimens were biopsied from the augmented area. The new bone formation of specimens was analyzed by histology and micro-computed tomography. Cone beam computed tomography (CBCT) scans were performed for measurements of residual crestal bone height under the sinus, the amount of increased height immediate after the augmentation and before implant insertion. To monitor stability changes, resonance frequency analysis was performed and implant stability quotient (ISQ) values were collected at implant placements (baseline,0 month), one month, three months and six months after placements.</p><p><b>RESULTS</b>All implants were loaded six months after insertion and no failures were recorded. Compared to adjacent native bone, no significant differences of bone volume fraction were found in augmented area (P > 0.05), together with lower trabecular number (P < 0.05) and trabecular thickness (P < 0.01) as well as higher trabecular separation (P < 0.01) by microradiographic analysis.Histomorphometrically, there was no significant difference in the amount of new bone formation between the adjacent native bone and augmented area (P > 0.05). CBCT showed a bone height gain of (14.19 ± 2.02) mm immediate after augmentation, which stabilized at (13.68 ± 1.95) mm after bone healing period. Mean ISQ value was 71.94 ± 6.51 at baseline, decreased to 70.19 ± 6.38 at 1 month, and increased to 78.17 ± 3.83 at 3 month and 82.56 ± 3.20 at 6 month.</p><p><b>CONCLUSIONS</b>The use of Bio-Oss as the sole graft is reliable and can lead to satisfactory bone formation and clinical outcome.</p>

Effect of sustained release of recombinant rat insulin-like growth factor-1 from poly (lactide-CO-glycolide ) microspheres on bone formation in the peri-implant areas in Goto-Kakizaki rats with type 2 diabetes / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the effect of sustained release of recombinant rat insulin-like growth factor-1(rrIGF-1) from poly (lactide-CO-glycolide) (PLGA) microspheres on bone formation in the peri-implant areas in Goto-Kakizaki rats with type 2 diabetes.</p><p><b>METHODS</b>Type 2 diabetes models were successfully established in 20 male Goto-Kakizaki rats, which were then randomly divided into treatment group (sustained release of rrIGF-1 from PLGA microspheres were loaded on the peri-implant areas, n=10) and diabetic group (loaded with isodose placebo from PLGA microspheres, n=10). Another ten male SD rats served as control group (did not sustain any loading). Titanium implants were inserted into the tibias of 30 diabetic and normal animals. Four, 5, and 8 weeks after implantation, local blood samples around the implants were obtained for the determination of serum osteocalcin (OCN), serum bone specific alkaline phosphatase (B-ALP), and serum procollagen I carboxyterminal propeptide (PICP) with enzyme linked immunosorbent assays.</p><p><b>RESULTS</b>Four weeks after implantation, OCN, B-ALP, and PICP were significantly lower in both treatment group and diabetic group than in control group(both P<0.05). Five weeks after implantation, serum OCN and B-ALP levels of the diabetic group were significantly lower than those of the other two groups (all P<0.05). Serum PICP levels of both diabetic group and treatment group were significantly lower than that of control group(both P<0.05). The OCN level in the trealment group was significantly higher in the post-operative 5th week than in the post-operative 4th week, while the PICP levels in the diabetic group were significantly lower than those in the treatment group and control group in the post-operative 8th week (both P<0.05).</p><p><b>CONCLUSION</b>Sustained release of rrIGF-1 from PLGA microspheres loaded on the local peri-implant areas can promote bone formation in the peri-implant areas in Goto-Kakizaki rats with type 2 diabetes.</p>

Optimized thread pitch design and stress analysis of the cylinder screwed dental implant / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To determine the optimal thread pitch for an experimental cylinder implant in Ansys Work-bench Design Xplorer environment.</p><p><b>METHODS</b>Finite element models of segment jaw bone with a V-shaped thread implant were created. The thread pitch (P) was set from 0.5 mm to 1.6 mm. The maximum Equivalent stresses (EQV stresses) in jaw bone and in implant were evaluated.</p><p><b>RESULTS</b>Under axial load, the amplification of maximum EQV stresses in cortical bone, cancellous bone and implant were 7.1%, 123.4% and 28.7% respectively. Under bucco-lingual load, the amplification of maximum EQV stresses in cortical bone, cancellous bone and implant were 2.8%, 28.8% and 14.9% respectively. When P exceeded 0.8 mm, the response curve curvature of maximum EQV stresses in jaw bone and in implant to P was ranged from -1 to 1.</p><p><b>CONCLUSION</b>Stresses in cancellous bone are more sensitive to thread pitch than in cortical bone. Stresses in jaw bone under axial load are easier affected by thread pitch than under bucco-lingual load. Thread pitch plays a greater role in protecting dental implant under axial load than under bucco-lingual load. Thread pitch exceed 0.8 mm should be the optimal design in a cylinder implant, but oversized pitch should be avoided too.</p>

Study on reference value of healthy teeth mobility of youth / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed to establish the reference value range of healthy teeth mobility in Chinese youth.</p><p><b>METHODS</b>200 right side teeth of Han nationality of Chinese youths were measured so as to get the range of the parameters.</p><p><b>RESULTS</b>All parameters of 14 teeth were achieved. The parameter of TM in mandibular incisor was the highest and in mandibular first molar lowest.</p><p><b>CONCLUSION</b>It is very significant to get and quantify the healthy teeth's parameter range. Because they can be served as the healthy contrast when dentists diagnose the mobility. It also reflects the fact that lower the TM parameter is, firmer the tooth will be.</p>

Improvement of osseointegration of titanium dental implants by a modified sandblasted surface / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study effects of the modified sandblasted surface of titanium implants, developed by authors, on the bone healing process.</p><p><b>METHODS</b>Osteoblasts were derived from the 5th passage of human fetal osteoblasts after primary isolation. Alkaline phosphatase (ALP) activities and protein contents of cellular layers, and osteocalcin contents in culturing medium were employed as criteria to evaluate osteogenic functions and differentiation of osteoblasts. The ALP activity was assayed utilizing the kinetic method, the protein content utilizing the Coomassie's method, and the osteocalcin content utilizing the radioimmune assay (RIA) method. Values of all criteria were divided by the corresponding cell numbers of different groups at a respective time point for the purpose of standardization. Samples were assigned to three groups-the modified sandblasted surface group, the smooth surface group and the blank control group, The culture was ended at, 4 days and 13 days.</p><p><b>RESULTS</b>At 4 days of culture, the modified sandblasted surface group showed a superiority to the smooth group with respects to the ALP activity [(17.390 +/- 1.595) nmol PNP x min(-1) x 10(-6) cells vs. (10.978 +/- 1.879) nmol PNP x min(-1) x 10(-6) cells] and protein content [(152.7 +/- 16.3) micro g/10(6) cells vs. (58.0 +/- 5.9) micro g/10(6) cells] of cellular layers and the osteocalcincontent [(43.0 +/- 6.1) ng/10(6) cells vs. (24.9 +/- 6.0) ng/10(6) cells] in culturing medium. Till the 13th day of culture, no differences were detected.</p><p><b>CONCLUSIONS</b>It is cytologically proved that the modified sandblasted surface can accelerate the bone healing process of implants though the improvement of osteoblastic functions and differentiation.</p>