[The effect on angiogenesis in guided tissue regeneration procedure using expanded polytetrafluoroethyene membranes in dogs].
OBJECTIVE
To observe the effect on angiogenesis in guided tissue regeneration procedures in which the barrier membranes were designed to be left for different time.


METHODS
Periodontal defects were created on buccal side of mesial root of mandibular third and fourth premolar in dogs. An experimental polytetrafluoroethyene (ePTFE) membrane was adapted to leave in place for 2, 3, 4 and 8 weeks,respectively. In the control defects(right mandibular second premolar), no membrane was used. At the end of 8 weeks,all the animals were perfused with a combined solution of carbon black ink and 10% formalin solution and killed. 500 microm thick specimens were processed. Descriptive histology was carried out,evaluating angiogenesis in area of new supraalveolar and gingival flaps.


RESULTS
Histologic analysis demonstrated that new vascular meshworks were built between the gingival flap and new connective tissue in the wound in 2-week,3-week and 4-week groups.However, in 8-week group, the number of supraalveolar blood vessels were fewer than that in other groups.But vascular rebuilt in gingival flap in 8-week group had come to normal.


CONCLUSIONS
The existance of nonresorbable membrane could affect the rebuilt of supraalveolar vascular meshwork, but it had no significant effect on the blood circulation in gingival flap. The revascularization between gingival flap and the new connective tissue was not significantly influenced after the membranes were removed from 2 to 4 weeks' placement.
Faculty of Stomatology, Shandong University, Shandong 250012, China. Samei@yeah.net
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AM
Song
P S
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Yang
Q F
QF
Sun
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Ge