Study on angle of immediate loading of immediate implant placement.

OBJECTIVE: To investigate the clinical immediate load at an angle after immediate placement of the implant. METHODS: Select 4 adult dogs; through establishing the angle loading animal experiment model, perform lateral loading on 32 implants respectively at vertical and 0°, 10°, and 20°, with which as a basis for grouping, determine the osseointegration index and new bone growth rate; and observe the peri-implant bone remodeling conditions. RESULTS: The 20° group is found with the most obvious bone absorption, and compared with other groups, its osseointegration index and new bone growth rate are statistically significant (P < 0.01); bone remodeling under 0° load stress is the best, with the formation of new bone and the highest bone contact ratio, which is the most reasonable under this the stress distribution compared with other angles. CONCLUSIONS: The implant stress distribution at 0° against the occlusal force direction is closer to physiologic optimum stress on the implant bone interface, and it is permitted for the long axis of the immediately implanted and immediately loaded implant to be tilted within about 10° against the load angle.

Adipose-derived stem cells transfected with pEGFP-OSX enhance bone formation during distraction osteogenesis.

This study was designed to investigate the effects of local delivery of adipose-derived stem cells (ADSCs) transfected with transcription factor osterix (OSX) on bone formation during distraction osteogenesis. New Zealand white rabbits (n=54) were randomly divided into three groups (18 rabbits per group). A directed cloning technique was used for the construction of recombinant plasmid pEGFP-OSX, where EGFP is the enhanced green fluorescence protein. After osteodistraction of the right mandible of all experimental rabbits, rabbits in group A were treated with ADSCs transfected with pEGFP-OSX, group B with ADSCs transfected with pEGFP-N1, and group C with physiological saline. Radiographic and histological examinations were processed after half of the animals within each group were humanely killed by injection of sodium pentothal at Week 2 or 6 after surgery. The distraction bone density was measured as its projectional bone mineral density (BMD). Three parameters were measured, namely, the thickness of new trabeculae (TNT), and the volumes of the newly generated cortical bone (NBV1) and the cancellous bone (NBV2) of the distracted regions. Good bone generation in the distraction areas was found in group A, which had the highest BMD, TNT, and NBV in the distraction zones among the groups. There was no significant difference in bone generation in the distraction areas between groups B and C. The results indicate that the transplantation of ADSCs transfected with pEGFP-OSX can effectively promote bone generation during distraction in vivo.

Transcription factor osterix modified bone marrow mesenchymal stem cells enhance callus formation during distraction osteogenesis.

This study was designed to investigate the effects of local delivery of bone marrow mesenchymal stem cells (BMMSCs) with or without osterix (OSX) gene transfected on bone regeneration in the distracted zone using a rabbit model of mandibular lengthening. Fifty-four New Zealand white rabbits underwent osteodistraction of the left mandible and were then randomly divided into group A, group B, and group C (n = 18 for each group). At the end of distraction BMMSCs transfected with OSX, autologous BMMSCs and physiological saline were injected into the distraction gaps in groups A, B, and C, respectively. Nine animals from each group were humanely killed at 2 and 6 weeks after completion of distraction. The distracted mandibles were harvested and processed for radiographic, histological, and immunohistochemical examination. Excellent bone formation in the distracted callus was observed in group A and group B; the former showed better bone formation and highest bone mineral density (BMD), thickness of new trabeculae (TNT, mm) and volumes of the newly formed bone area (NBV) in the distraction zones. Group C animals showed poor bone formation in the distracted callus when compared with groups A and B. Positive immunostaining of bone sialoprotein (BSP) was observed in the distracted callus in all groups; however, BSP expression was much stronger in group A than in groups B and C. The results of this study suggest transplantation of BMMSCs can promote bone formation in DO; OSX-mediated ex vivo gene therapy was more effective during bone deposition and callus formation in distraction osteogenesis.

[An experimental study of intra-articular injection of NG-methyl-L-arginine for the treatment of indirect temporomandibular joint trauma in goats].

PURPOSE: To investigate the efficacy of NG-methyl-L-arginine(L-NMMA) for treatment of indirect temporomandibular joint trauma in goats. METHODS: Trauma to TMJ in 9 goats were exerted under an impact to the right and left mandibular angle with self-made device, L-NMMA (0.5 mL) were injected into the right TMJs after 3 hours, 7 days, 14 days, 21 days; the left TMJs were injected with normal saline and used as a control. The goats were killed after 3 months. The TMJs of goats were examined with scanning electron microscopy and light microscopy when sacrificed and scored in a subjective manner following the standard criteria which was a modification of the method by Mankin et al and Yoshimi et al. GLM model of SAS 9.0 software package was used to evaluate the scores of the treatment sides and control sides. RESULTS: Under light microscopy and scanning electron microscopy, the left TMJ tissues showed severe osteoarthrotic changes in the temporal surface,disk and condyle, the right TMJ tissues showed significant improvement (P<0.05). CONCLUSIONS: Repeated intra-articular injection of L-NMMA may reduce the destruction of indirect trauma on goat TMJs.

Transarterial embolization of a high-flow maxillary arteriovenous malformation fed by multiple arteries.

A high-flow maxillary arteriovenous malformation fed by multiple arteries, including bilateral internal maxillary arteries and ophthalmic artery, is reported. A combination of polyvinyl alcohol particles and N-butyl-cyanoacrylate mixed with lipiodol was progressively deposited within the distal vascular bed by transarterial superselective embolization of the branches of bilateral internal maxillary arteries, resulting in complete anatomic and clinical cure. The authors feel that this approach is more secure and effective compared with transfemoral venous embolization and direct transosseous puncture. It also avoids mutilating surgery.

[Association of transforming growth factor-alpha gene polymorphism and environment factors with nonsyndromic cleft lip with or without cleft palate in Han nationality].

OBJECTIVE: To study the association of transforming growth factor-alpha (TGF-alpha gene polymorphism and environment factors with nonsyndromic cleft lip with or without cleft palate (NSCLP) in Han nationality. METHODS: Data related to infection, drug intake and folic acid supplement during pregnancy were gained through investigation of mothers. Polymerase chain reaction combined with restrict enzyme digestion was used to detect the target gene variation in 199 patients with NSCL/P and 203 healthy controls. Analysis was carried on the genotype and infection,drug intake and folic acid supplement. RESULTS: The C2 allele frequency in patients with NSCL/P was significantly higher than that in healthy controls. There was a significant increase of patients with NSCL/P in pregnant women exposed to infection, drug intake and folic acid deficiency. There was an interaction between C1C2 genetype and infection, drug intake and folic acid supplement. CONCLUSION: TGF-alpha gene polymorphism is associated with NSCL/P. Infection, drug intake and folic acid supplement during pregnancy were associated with the occurrence of NSCL/P. Individuals containing C2 allele were more sensitive to infection, drug intake and folic acid deficiency.

[Relationship between transforming growth factor-alpha gene polymorphism and non-syndromic cleft lip with cleft palate].

OBJECTIVE: To study the association of TGF-alpha gene polymorphism and non-syndromic cleft lip with cleft palate in Shandong province. METHODS: Polymerase chain reaction combined with restrict enzyme digestion was used to detect the target gene variation in 98 patients with non-syndromic cleft lip with cleft palate and 101 healthy controls. RESULTS: The C2 allele frequency in patients with non-syndromic cleft lip with cleft palate was significantly higher than that in healthy controls. The genotype frequency in patients with positive family history was significantly higher than that without positive family history. CONCLUSION: TGF-alpha gene polymorphism is closely associated with non-syndromic cleft lip with cleft palate in Shandong, especially in patients with positive family history.

[Application of low intensity ultrasound in the extraction of totally impacted mandibular third molars].

PURPOSE: To observe the clinical effects of low intensity ultrasound in extraction of totally impacted third molars. METHODS: 40 patients with totally impacted third molars on both sides of the mandible verified by X-ray were selected. After extraction of the teeth, the socket on one side was treated with low intensity ultrasound while the other side underwent no treatment. Statistical analysis was performed with SPSS 10.0 on all patients in form of pain, swelling, dry socket and bone healing. RESULTS: In the experimental group, 4 patients complained of severe pain while 16 patients in the control group (P < 0.05). Moderate or severe swelling were not uncommon in both experimental and control groups (P > 0.05); No patients suffered from dry socket in the experimental group and 4 patients suffered from dry socket in the control group (P < 0.05); There were 35 patients with complete bone healing in the experimental group while 21 patients with complete bone healing in the control group (P < 0.01). CONCLUSIONS: The use of low intensity ultrasound in extraction of totally impacted mandibular third molars reduced the severity of post-operative pain and the incidence dry socket, and it also stimulated bone healing, but it showed no effect on relieving post-operative swelling.

[Histopathological study of the effects of intra-articular injection of triamcinolone acetonide on temporomandibular joint osteoarthrosis in goats].

PURPOSE: The aim of this study was to investigate the histopathological changes of human temporomandibular joint osteoarthrosis following intra-articular injection of triamcinolone acetonide, and compare the results to these of control group. METHODS: The upper compartments of both joints of 10 goats were injected with 0.8 ml collagenase I to induce osteoarthrosis. The 10 goats were then equally divided into control group and experimental group. The first and second treatment were carried out 30 and 60 days after injection of collagenase I, respectively. The animals were sacrificed 90 days after the first treatment. The specimens of the animal TMJ were harvested, histologically examined under light microscopy and scanning electron microscopy, and scored in a subjective manner following the criteria which was a modification of the method of Mankin et al and Yoshimi et al. GLM model in SAS software package was adopted to compare the differences between the control group and experimental group. RESULTS: Under light microscopy and scanning electron microscopy, the condyle, meniscus and glenoid fossa of the control group demonstrated distinct osteoarthrosis; the histopathologic changes in the experimental group was more serious than the control group, and the differences of the histologic scores were significant between the two groups (P<0.01). CONCLUSION: Intra-articular injection of triamcinolone acetonide as a lytic agent will worsen for articular cartilage reparation.

[Clinical study of bioglass for repairing alveolar cleft.].

PURPOSE: To analyse the results of using Bioglass to repair alveolar cleft. METHODS: Thirty-nine cases with alveolar cleft were divided into two groups. In group A, autogenous iliac cancellous bone were transplanted into the cleft to repair alveolar defect in 25 cases, while artificial bone-Bioglass was used in group B of 14 cases. The results of two groups were compared with a follow up of 12 months. RESULTS: New bone formation was perfect in grafted area and canines can emerge from the bone grafted areas observed from the X-ray films both in group A and group B. Statistical analysis showed no significant difference between group A and group B in the clinical success rate of alveolar cleft repair. However, there was significant difference between complete alveolar cleft and incomplete alveolar cleft in group A and group B. CONCLUSION: Bioglass can result in new bone formation and eruption of canines from the bone grafted areas. The application of Bioglass in repairing of alveolar cleft provides a new therapy for alveolar cleft patients.

[Changes of mitochondrial calcium, adenosine triphosphate and adenosine diphosphate contents induced by occlusal trauma in rabbit's masseter muscles].

OBJECTIVE: To study the role of Ca2+ overload and energy metabolism in mitochondria in masticatory muscle dysfunctional induced by occlusal trauma. METHODS: Mitochondrial Ca2+ contents were measured with atomic emission spectrophotometer. Mitochondrial ATP and ADP contents were measured with high performance liquid chromatography. RESULTS: (1) Mitochondrial Ca2+ contents of masseter muscle ipsilateral to metal splint in ten and twenty days' experimental groups and that contralateral to metal splint in twenty days' experimental group increased significantly (P < 0.05). (2) Mitochondrial ATP contents of masseter muscle ipsilateral to metal splint in experimental groups were higher than that in control groups and contralateral to metal splint after twenty days. (3) Mitochondrial Ca2+ contents of masseter muscle ipsilateral to metal splint were significantly negatively correlated to the mitochondrial ATP contents (r = -0.780, P < 0.05). CONCLUSION: Ca2+ overload in mitochondria depresses ATP production, which results in energy metabolism disorder in masticatory muscle cells. It may play an important role in the mechanism that occlusal trauma results in masticatory muscle dysfunction.