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Hong-zhi Zhou

Publications and source records attributed to Hong-zhi Zhou.

8 recordsLinked to original sources
PubMed2006

[Bone mineral density and biomechanical characters of the augmented alveolar ridge by distraction osteogenesis using Ti-Ni shape memory alloy distractor].

OBJECTIVE: To evaluate the quality of the alveolar ridge augmented by Ti-Ni shape memory alloy (Ti-Ni SMA) distractor. METHODS: All of the mandibular premolars and the first molars were extracted from 12 adult mongrel canines. One month later, box-shaped osteotomy was carried out in the left mandibles and Ti-Ni SMA distractors were imbedded. The right sides served as blank control. The canines were killed 3 or 6 months later and specimens were taken from corresponding area of the experiment sides and the control. Bone mineral density and biomechanical function were measured. RESULTS: Bone mineral density, ultimate compressive strength and Young's Modules of the augmented ridge were lower than the blank control three months after distraction. But the indexes increased and showed no significant difference with the control six months after distraction. CONCLUSIONS: The canines mandibular posterior alveolar ridge could be augmented by distraction osteogenesis using Ti-Ni SMA distractor, and the new bone is strong enough for implant placement.

Alveolar Ridge Augmentation↗
PubMed2005

[Effects of different TiNi-SMA distractor on the height of alveolar ridge augmentation].

OBJECTIVE: To discuss the effects of titanium nickel shape memory alloy (TiNi-SMA) distractor with different stretching force and different distance between two fixed ends on the height of alveolar ridge augmentation. METHODS: The mini distractors were all made of TiNi-SMA wire. The maximum stretching force and the distance between two fixed ends according to different distractors (A, B and C) were 20 mm, 700 g; 15 mm, 1000 g; 20 mm, 1000 g. 15 adult mongrel canines were divided into three groups randomly and extracted the mandibular premolars and first molar. One month later, box-shaped osteotomies of the alveolar bone were carried out in the left mandible and the TiNi-SMA distractors were buried. The bone height was measured and the radiographs were taken before and five weeks post operation continuously. RESULTS: One week post operation, the vertical ridge augmentation of group A, B and C averaged (7.55 +/- 1.02) mm, (4.97 +/- 0.34) mm, (8.54 +/- 0.82) mm and the height remained (7.20 +/- 1.05) mm, (4.93 +/- 0.21) mm, (8.04 +/- 0.78) mm five weeks post operation. There was no statistic difference in the height of alveolar ridge augmentation between Group A and C, but Group B showed significant difference with the other two groups. In each group, the height did not changed significantly with the time. The radiographs showed obvious distraction gap post operation, and the new bone regenerated five weeks later. CONCLUSION: It suggests that in the scope of suitable stretching force, the height of alveolar ridge augmentation was determined by the size of TiNi-SMA distractor, that is to say, determined by the distance between the two fixed ends.

Adult↗
PubMed2005

[Design and application of internal devices for automatic elasticity distraction osteogenesis].

OBJECTIVE: To improve the design of the devices used for autoatic elasticity distraction osteogenesis, and to preliminarily testify their feasibility for clinical application. METHODS: The internal automatic distraction devices were constructed by three parts, including sinusoid shape memory alloy distractor, reconstructive plate and mini-plate. The animal model of trifocal bone transport reconstruction of canine mandibular mentis was duplicated, in which a 6 cm mandibular mentis segment was removed and the transport disc was created by osteotomy in both ends of the mandibular defect. The plates were used for internal fixation and shape reconstruction of the mandible. They also served as transport distraction guidance for the elasticity distractor. RESULTS: The new devices could complete bone transport as expected. Regenerated bone segments were formed in two months and both sides of the mandibular body were lengthened. Because of the narrow angle and obstruction from the thick soft tissues in the mentis area, the ultimate symphysis mentalis was not reconstructed. CONCLUSION: The design of the internal elasticity distraction devices showed potential feasibility for clinical practice. But further studies are still needed for better control of the strength and balance of distraction forces.

Animals↗
PubMed2005

[Segmental mandibular reconstruction by elasticity distraction osteogenesis associated with guided bone regeneration].

OBJECTIVE: To accelerate distraction osteogenesis by utilizing guided bone regeneration technique, and to improve the automatic process of canine segmental mandibular reconstruction by elasticity distraction osteogenesis using shape memory metal alloy distractor. METHODS: Adult hybrid canines were used. Osteotomy was performed to remove a bone segment of 2.5-4.0 cm in one side of the mandible. Mandibular fixation devices and shape memory metal alloy distractor were secured according to the principles of bi-focal distraction technique. A piece of ePTFE membrane was sutured to cover the buccal side of bone defect and osteotomy gap of transport disc, where the periosteum was peeled for exposing mandible in operation. Then the incisions were totally closed. The canines were sacrificed 3 months later to harvest the mandibles for morphological observation and measurement of bone density and intensity. RESULTS: The shape memory metal alloy distractor performed distraction osteogenesis automatically and reconstructed the mandibles with bone defect. A regenerated bone segment of 1.5-2.0 cm was formed in the compression region between transport disc and contralateral mandibular end. The new bone in both of distraction and compression regions had similar height and thickness with normal mandible. Moreover the new bone density and intensity were rather satisfied. CONCLUSIONS: Membrane guided bone regeneration can avoid bone synthesis commonly caused by cicatrization of soft tissue in the bone defect, and accelerate ossification and maturation of new generated bone.

Animals↗
PubMed2004

[Le Fort III osteotomy and medium position distraction for mid-facial hypoplasia].

OBJECTIVE: To probe the possibility of distraction osteogenesis for correction of mid-facial hypplasia using a new technique. METHODS: The distraction system of mid-facial skeleton consisted of a face-bow, the elastic loops and a device that hitched to bone holes made in the aperture rim. Flllowing Le Fort III osteotomy, a bone hole was drilled at each side of the external-inferior rim of the aperture by a dental bur. The traction device was hitched to the holes through the nostrils. Distraction began three days postoperatively, with the force adjusted dependently upon the rate of progress. When the skeleton reached to the planed position, distraction was retained with a minor force for 8 weeks. Three adults with mid-facial hypoplasia underwent this treatment. RESULTS: The mid-facial skeleton showed a balanced advancement. The patients' facial contour and occlusal relationship recovered completely. CONCLUSIONS: Patients with severe mid-facial hypoplasia could be corrected ideally by the new technique, with balanced advancement of mid-facial skeleton, minor trauma. The design of distraction system was reasonable. The manipulation of the procedure was easy.

Adult↗
PubMed2003

[Induction of lymphangiogenesis by mouse ascites hepatoma cell H22 in vitro].

OBJECTIVE: To construct lymphangiogenesis model of Balb/c mouse in vitro to observe the impact of mouse ascites hepatoma cell H22 on the lymphangiogenesis and lymphatic endothelial proliferation. METHODS: Intraperitoneal benign lymphangioma induced by incomplete Freund's adjuvant in Balb/c mouse was harvested and embedded in fibrin gel to culture in vitro with conditioned medium (CM) of H22 cell. The gels, observed by inverted microscope and transmission electron microscope, were then digested to separate the cells. The expression of Flt-4, c-fos and iNOS in the cell and the content of NO in medium were studied by immunohistochemical and histochemical method. RESULTS: Lymphatic capillary generating from lymphangioma specimen in the gels was observed by inverted microscope and transmission electron microscope. H22 CM was observed to enhance growth of the vessels, induce expressions of Flt-4, c-fos and iNOS in the separated cells and increase content of NO in the medium. CONCLUSION: The model is convenient for in vitro study of lymphangiogenesis. H22 cell can accelerate lymphangiogenesis, which warrants further study for the understanding of the role of lymphangiogenesis in metastasis.

Animals↗
PubMed2003

[Reconstruction of segmental mandibular defect of canine using titanium-nickel distractor].

OBJECTIVE: To establish a continuous and automatic distraction osteogenesis technique in reconstruction of segmental mandibular defect by using embedded titanium-nickel alloy distractor with characteristics of shape-memory and super-elasticity. METHODS: Adult hybrid canines were used as the animal model. Segmental defects of 1-3 cm in the body of mandible were created by surgical osteotomy. Bi-focal distraction osteogenesis was applied using embedded titanium-nickel distractor designed by the authors. The canines were sacrificed 3 months after the operation and the mandibles were harvested to examine the results of bone regeneration. RESULTS: The histocompatibility of titanium-nickel distractors was good. Distraction osteogenesis was completed automatically and the defects were elementarily restored. Radiological and histological examination showed well bone regeneration in distraction area. CONCLUSIONS: Distraction osteogenesis using embedded self-loading titanium-nickel distractor could be a hopeful and useful technique. It might help to solve the problems of functional mandibular reconstruction in the near future.

Animals↗