Distraction osteogenesis for repair of cleft palate: an experimental study / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the repair of cleft palate (CP) bone defect under the application of distraction osteogenesis (DO); to investigate the correction mechanism in thin bone of palatal shelf and to search a possible new treatment approach for repair of CP.</p><p><b>METHODS</b>14 cats were assigned randomly to 3 groups: (1) Empty control, 2 cats unoperated with euthanasia at the end of 2 weeks; (2) Experimental control, 2 cats underwent 8 mm x 18 mm palatal osteoectomy in saggital direction as the experimental model of CP with euthanasia in 6 weeks; (3) Experimental group, 10 cats were performed the same palatal osteoectomy as group (2), the newly designed and individual manufactured intraoral distractors were fixed to teeth by brackets and to bilateral palate bone across the defect with titanium miniscrews. 4 weeks later the transport disc (TD) osteotomy were performed and gradual distraction was started after 6 days latency period at the rate of 0.4 mm x 2/day till the TD reached the opposite edge of the CP. Roentgenographic, gross meterage and ultrastructural observation were performed 2, 4, 6, 8, 12 weeks after completion of distraction.</p><p><b>RESULTS</b>All the examinations revealed the TD recombination to the opposite bone edge of the CP, simultaneously, the proportional expansion of overlay mucoperiosteal flap was achieved. The bone defect were filled with de move osteogenesis. Roentgenographically, the new bone mineralization was along the DO vector, developed from the bone cut edges bilaterally to the central translucent zone until turned to thin fissure. Comparison of the plaster casts showed no change in the occlusion or dentomaxillofacial framework.</p><p><b>CONCLUSIONS</b>The intraoral distractor is able to get both effective distraction and steady fixation. The examination results suggest that the CP bone and soft tissue defect could be repaired and acheived functional reconstruction under DO, which could be a new treatment approach for repair of CP.</p>

Distraction osteogenesis for the repair of cleft palate--an ultrastructural study / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The aim of this study was to explore ultrastructural characters of the newly formed bone in the correction of cleft palate (CP) bone defect by distraction osteogenesis (DO).</p><p><b>METHODS</b>The CP experimental animal models (12 cats) were established surgically, and were divided randomly into the experimental group (10 cats), in which the hard palate bone defects were corrected with DO procedure at the rate of 0.4 mm x 2/day. The specimen retrieval with euthanasia was carried out at 2, 4, 6, 8, 12 weeks after completion of distraction. Ultrastructural study was then performed; the experimental control group (2 cats) was kept for 6 weeks before euthanasia without any correction, the other extra 2 cats were used as the negative control.</p><p><b>RESULTS</b>New bone formation appeared in early 2 weeks. Exclusively intramembranous bone formation was observed in all specimens. The remodeling activities were keep observed throughout the period of study, and the bone structure matured gradually till 12 weeks after the completion of DO. No repair was observed in experimental control group.</p><p><b>CONCLUSION</b>The reconstruction of CP bone defect by means of DO could get active intramembranous bone formation and remodeling, which adapted to normal functional activities.</p>

Characteristics of BMP expression and X-ray films in distraction osteogenesis for repair of cleft palate--an immunohistochemical and roentgenographic study / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purpose of this study was to observe the roentgenographic characters of distraction osteogenesis (DO) correction of cleft palate (CP), to study the expression of BMP proportional to fixation period time intervals, and to explore the new bone formation mechanism in Cleft Palate bone shelf.</p><p><b>METHODS</b>12 cats were used to establish the CP animal model surgically, and then were assigned randomly to (1) Experimental group (12 cats): CP defects were DO repaired at the rate and rhythm of 0.4 mm x 2/day. Specimen retrieval at 2, 4, 6, 8, 12 weeks after completion of distraction, roentgenography and Anti-BMP immunohistochemistry studies were performed; (2) Experimental control group (2 cats): CP defects without any treatment procedures, and (3) Empty control group of 2 cats.</p><p><b>RESULTS</b>Anti-BMP immunohistochemistry study showed positive DAB dye in early 2 weeks and most extensively positive expression of BMP in 4 to 6 weeks. The expression of BMP wore off gradually through 8 to 12 weeks. The roentgenography showed that the newly mineralized bone was developed from the cut bone edges bilaterally to the central transparent zone, and the newly formed bone bridged the defect area completely at the end of the study. The CP bone defect was reconstructed and the distraction gap was filled with de nove osteogenesis. No new bone formation was observed in experimental control group.</p><p><b>CONCLUSION</b>The process of new bone formation in the distraction area is dynamic. Being stimulated primarily, the process was kept highly active till quiescence phase finally. The X-ray examination shows that there is distinctively low roentgenopeque. Nevertheless, roentgenography is so far a very effective and convenient method to evaluate and monitor the DO correction efficiency.</p>

Distraction osteogenesis for repair of cleft palate──Histological and fluorescent labeling study / 实用口腔医学杂志

Objective: To observe the mechanism and characteristics of new bone formation and remodeling process during distraction osteogenesis (DO) in the reconstruction of bone defect in cleft palate (CP). Methods: Sagittal palatal osteoectomy were performed in 12 cats to establish the CP model. The CP defects were reconstructed by intraoral distractors at the rate and rhythm of 0.4 mm?2/day till the transport disc (TD) reached the opposite edge across the defect region. Tetrachloride fluorescent labeling was administered 6 days before euthanasia specimen retrieval at 2, 4, 6, 8, 12 weeks through fixation period. Histological and fluoroscopical study were performed; control groups (2 animals in each group) were set for comparison. Results: The bone defect of CP was successfully reconstructed by DO. Exclusively intramembranous de novo osteogenesis were observed. Soft tissues attaching to TD were elongated simultaneously. No spontaneous repair was observed in control animals. Conclusion: With effective distraction and steady fixation, CP bone and soft tissue defect can be reconstructed by active intramembranous bone formation and remodeling following the applicaion of DO.