Positional relationship between branches of the facial nerve and the plane of angulus oris: an anatomical study / 中华口腔医学杂志

Objective@#To investigate the relationship between the inferior buccal branch and mandibular marginal branch of the facial nerve in the plane of angulus oris.@*Methods@#Twenty unilateral adults cadaveric heads were dissected. In the vicinity of the posterior border of mandibular ramus, the positional relationship between mandibular marginal branch and the plane of angulus oris, the inferior buccal branch and the plane of angulus oris was recoded and analyzed.@*Results@#In 18 of the 20 samples, the plane of angulus oris was between the inferior buccal branch and mandibular marginal branch in the vicinity of the posterior border of mandibular ramus. In one sample, the plane of angulus oris was below the inferior buccal branch and mandibular marginal branch in the vicinity of the posterior border of mandibular ramus. Another sample was excluded because the starting points of the inferior buccal branch and mandibular marginal branch were in front of the posterior border of mandibular ramus. The distance from the intersection of the posterior border of mandibular ramus and the plane of angulus oris to the intersection of inferior buccal branch and the plane of angulus oris was (14.96±8.55) mm.@*Conclusions@#In most cases studied, the plane of angulus oris is between the inferior buccal branch and mandibular marginal branch in the vicinity of the posterior border of mandibular ramus. Along the plane of angulus oris, within 1.0 cm anterior to the posterior border of mandibular ramus, it is a relatively safe place for surgical approach.

The effects of hyaluronic acid and TGF-β1 on the growth of mandibular condylar cartilage and the hyperthophic differentiation of the condylar chondrocyts / 实用口腔医学杂志

Objective:To study the effects of hyaluronic acid(HA) and TGF-β1 on the growth of mandibular condylar cartilage and the hyperthophic differentiation of the condylar chondrocyts.Methods:60 condyle samples from newborn mice were in vitro cultured and treated with HA(0.5 mg/ml),TGF-beta 1 (5 ng/ml) and without additional agent(the control) respectively.The Morphological observation,Alizarin Red Staining,Alkaline phosphatase staining and condylar cartilage surface area measurement were conducted after 1,2,4,6 and 8 weeks of culture respectively.Results:High-density photoresist area was observed in the condylar cartilage of the control group after 4 weeks of culture.Alizarin Red Staining and Alkaline phosphatase staining showed condylar cartilage matrix production and calcification.The HA group showed no high-density photoresist area at all time points,however,the cartilage area was significantly increased (P ＜ 0.05);the TGF-beta 1 group showed high-density photoresist area after 2 weeks of culture.but the cartilage area were not significantly changed(P ＞ 0.05).Conclusion:HA can promote the growth of condylar cartilage in vitro,but have an inhibitory effect on chondrocyte differentiation.TGF-β1 plays a role in mandibular condylar chondrocyte hypertrophic differentiation in the early days of in vitro culture.

[Efficacy of systemic administration of oxytocin on implant osseointegration in osteoporotic rats].

OBJECTIVE: This study investigated the effects of systemic administration of oxytocin (OT) in osteoporotic rats on implant osseointegration. METHODS: Twenty rats were randomly assigned to the control and experimental groups. Initially, the rats underwent bilateral ovariectomy. After 12 weeks, an osteoporosis model was established. Each rat received an implant at the distal and middle femoral metaphysis. Simultaneously, systemic administration was conducted with one group receiving subcutaneous injection of OT (1 mg·kg⁻¹ per day), whereas the other group received placebo injection. After treatment for 4 weeks, another surgery was conducted to remove the thigh bones from the rats containing the implants for an eight-week observation. With the employment of micro-CT, histological observation and push-out test, osseointegration was evaluated. While the rats received thigh-bone removal surgery, another surgery was conducted to remove the tibia metaphysis from the rats of both groups to perform histological observation and micro-CT inspection. RESULTS: The trabecular bone of tibial samples was intensive and formed woven mesh structure in the experimental group compared with the control group. In the experimental group, the relative bone volume/tissue volume surrounding the implant, the bone contact ratio, and the maximum push-out force of the implant were 0.35%±0.06%, 67.25%±9.06%, and (70.32±10.91) N, respectively, the corresponding values were 0.11%±0.02%, 43.25%±7.01% and (21.65±4.36) N in the control group, and the experimental group increased significantly compared with the control group (P<0.05). CONCLUSIONS: Systemic administration of OT cannot only antagonize the negative effects of osteoporosis but can also promote implant healing and osseointegration of pure titanium implants.

Efficacy of systemic administration of oxytocin on implant osseointegration in osteoporotic rats / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study investigated the effects of systemic administration of oxytocin (OT) in osteoporotic rats on implant osseointegration.</p><p><b>METHODS</b>Twenty rats were randomly assigned to the control and experimental groups. Initially, the rats underwent bilateral ovariectomy. After 12 weeks, an osteoporosis model was established. Each rat received an implant at the distal and middle femoral metaphysis. Simultaneously, systemic administration was conducted with one group receiving subcutaneous injection of OT (1 mg·kg⁻¹ per day), whereas the other group received placebo injection. After treatment for 4 weeks, another surgery was conducted to remove the thigh bones from the rats containing the implants for an eight-week observation. With the employment of micro-CT, histological observation and push-out test, osseointegration was evaluated. While the rats received thigh-bone removal surgery, another surgery was conducted to remove the tibia metaphysis from the rats of both groups to perform histological observation and micro-CT inspection.</p><p><b>RESULTS</b>The trabecular bone of tibial samples was intensive and formed woven mesh structure in the experimental group compared with the control group. In the experimental group, the relative bone volume/tissue volume surrounding the implant, the bone contact ratio, and the maximum push-out force of the implant were 0.35%±0.06%, 67.25%±9.06%, and (70.32±10.91) N, respectively, the corresponding values were 0.11%±0.02%, 43.25%±7.01% and (21.65±4.36) N in the control group, and the experimental group increased significantly compared with the control group (P<0.05).</p><p><b>CONCLUSIONS</b>Systemic administration of OT cannot only antagonize the negative effects of osteoporosis but can also promote implant healing and osseointegration of pure titanium implants.</p>

[Effect of recombinant human parathyroid hormone 1-34 on mandibular distraction osteogenesis in rabbits].

OBJECTIVE: To explore the effect of recombinant human parathyroid hormone 1-34 [rhPTH(1-34)] on bone regeneration rabbit mandible during distraction osteogenesis (DO). METHODS: 40 Japanese white rabbit (weight 2.0-2.5 kg) were randomly divided into control group and groups. The experimental groups were divided inito 12.5, 25 and 50 µg/kg group according to the dosage of rhPTH (1-34) in each group. Each group involved 10 rabbits, and unilateral DO models were established at the right mandible of the rabbits. From the first day of distraction to the day of execution, the rabbits in the experimental groups were injected subcutaneously rhPTH (1-34) of the corresponding dose respectively, and the rabbits in the control group were injected subcutaneously 2% heat inactivated rabbit serum 1 ml respectively.. Five rabbits in each group were executed respectively at 1 week and 3 weeks after completion of distraction, and the specimens of DO were harvested. The gross observation, X-ray examination, and histological study were performed. RESULTS: Gross appearance: At the first week of consolidation, the dense and opaque white tissue was seen in the distraction gap of the 50 µg/kg group, and the white translucent tissue was seen in the distraction gaps of the rest groups. At the third week of consolidation, the greyish white tissue was seen in the distraction gap of the control group, while the cartilage-like tissue was seen in the buccal side of the distraction gap of the 12.5 µg/kg group, the color of new-formed tissues was close to that of normal bone tissue in the lingual side. The buccal tissue at the edge of the distraction gap of the 25 µg/kg group fitted together with the primary bone tissue in its two sides. It was difficult to distinguish the boundaries between the distraction gap and the bone tissues in its two sides in the 50 µg/kg group. X-ray findings: At the first week of consolidation, a sparse opaque image was seen in the distraction gap of the 50 µg/kg group, and a low-density image was seen in the distraction gap of the rest groups. At the third week of consolidation, a sparse bone image was seen in the control group, and the edge of the bone was not continuous. With the increase of the dose in the experimental groups, the image of the distraction gap became more and more opaque, and the image of the distraction gap in the 50 µg/kg group was close to that of the normal bone tissue. HISTOLOGICAL FINDINGS: At the first week of consolidation, few osteoblasts were present at the edge of the distraction gap of the control group. A large number of bone cells and bone trabecular were present in the distraction gap of the 12.5 µg/kg group, the network of the bone trabecula was present in the 25 µg/kg group, and a few new bones were found in the 50 µg/kg group. At the third week of consolidation, the network of the trabecular bone was present in the distraction gap of the control group, while the network of the bone trabecula was present in the 12.5 µg/kg group, a lot of bone-like tissues in the 25 µg/kg group, and near-mature bone in the 50 µg/kg group. CONCLUSIONS: rhPTH(1-34) can promote the formation of new bone in the distracted gap during mandibular DO in rabbits.

Effect of Angiogenesis inhibitor (TNP-470) on the morphology of GNM cell line in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purpose of this study was to investigate the effect of an angiogenesis inhibitor (TNP-470) on the ultra micro-structural morphological changes of GNM cell line, which was derived from human oral squamous cell carcinomas in vitro.</p><p><b>METHODS</b>The GNM cells were cultured and, the effect of TNP-470 on ultra micro-structural morphological changes of GNM cells was observed under the inverted microscope, the scanning electron microscope (SEM) and the transmission electron microscope (TEM).</p><p><b>RESULTS</b>Numerous round cells, shrinkage of cellular membrane and dead cells were observed 48 hours after 2 micrograms/ml of TNP-470 was added into the GNM cellular suspension. After 72 hours, GNM cells became shortened and, the number of microvilli of the cellular surface was observed under the SEM and TEM. A large number of GNM cells turned into necrosis, accompanying with the destruction of mitochondria and endoplasmic reticula.</p><p><b>CONCLUSION</b>TNP-470 has a strong tumor cytotoxic effect on GNM cells, which may be due to its destructibility on mitochondria and endoplasmic reticula of GNM cells. TNP-470 can alter the surface structure of GNM cell membrane, which suggests that TNP-470 may interrupt the metastasis of GNM cells.</p>