| objective The aim of the present study was to evaluate the effect of hyperbaric oxygen on healing of extraction socket and grafted extraction,and to provide a experimental basis for the wide application of hyperbaric oxygen in the preservation of extraction socket.Methods :A total of 8 beagle dogs were utilized in this study,and were randomly divided into hyperbaric oxygenation(HBO) group and normobaric oxygenation(NBO) group of 4 animals each.The lateral incisor of the 4 quadrants of the mandibular and maxilary of animals were extracted,a total of 4 extraction socket.The fresh extractions of the first and third quadrant were non-grafted and were used to carry out experiment 1, while the corresponding in the fresh extractions of the second and fourth quadrant were grafted with Bio-oss bone substitution material and were used to carry out experiment 2. Animals of HBO group received HBO treatment(100%O2, 2.4 absolute atmospheric pressure, 90-min/per day, 5days/week, a total of 6 weeks). Animals of NBO group served as normobaric,breathing room air. Four animals in each group were sacrificed respectively at 4 and8 weeks. The experimental sites specimens of experiment 1 and experiment 2 were analysed by clinical examination, CBCT, histological examination and morphometric measurements, and vascular endothelial growth factor(VEGF) and bone morphogenetic protein-2(BMP-2) expressions of specimens were analysed by using immunohistochemistry.Results: Experiment1. At 4 and 8 weeks, clinic exmination analysisdemonstrated the both width and contour of the socket of NBO samples were reduced compared to HBO;radiographic analysis demonstrated the height difference of extraction socket of NBO samples was increased compared to HBO,and the formation and dense of new bone of NBO samples were reduced compared to HBO.Histomorphometric analysis demonstrated the formation,mineralizing and remodeling of the new hard tissue were increased within HBO-treated extraction compared to NBO-treated extraction at 4 and 8 weeks.The new bone of HBO and NBO were respectively at 4 weeks( HBO vs NBO, mean%±SD : 81.6%±4.93vs63.0%±6.5).The bone marrow of two groups at 8 weeks were respectively(HBO vs NBO,mean%±SD : 85.7%±8.71 vs 69.7%±12.34).Expressions of the VEGF and BMP-2 in 4 weeks HBO samples were elevated compared to NBO. Staining of the VEGF and BMP-2 in 8 weeks HBO samples were elevated compared to 8 weeks NBO and were similar to 4 weeks NBO samples.Experiment 2 : Healing of grafted extractions, at 4 and 8weeks, clinic examination analysis demonstrated the both width and contour of the sockets will not to be significantly reduced in two groups; radiographic analysis demonstrated height difference will not to be significantly change of the sockets in two groups,however, the formation and dense of new bone of NBO samples were reduced compared to HBO. Histomorphometric analysis demonstrated more bone information within HBO-treated grafted extraction compared to NBO-treated grafted extraction.The new bone percentage of two groups were respectively at 4 weeks(HBO vs NBO, mean%±SD:50.6%±10.26 vs 31.0%±17.05).The new bone and bone marrow of two groups were respectively at 8 weeks( HBO vs NBO,mean%±SD:40.0%±1.0 vs 32.7%±3.05;HBO vs NBO, mean%±SD:38.0%±10.53 vs 21.0%±9.53), and the Bio-oss particles that frequently were coated by osteoclastscells,were occupied by a non-mineralized connective tissue in NBO-treated grafted extraction.Cells stained for VEGF and BMP-2 were the most intense in 4 weeks HBO samples was elevated compared to NBO samples. Althought, there were a decline in expression of the VEGF and BMP-2 between the HBO and NBO groups 8weeks postsurgery, VEGF and BMP-2 expressions in HBO samples was elevated compared to NBO samples.Conclusions: HBO had beneficial effects on formation and remoding of the new bone of the socket, and reduces the horizontal and vertical bone resorption during the healing process of the extraction socket.Meanwhile, hyperbaric oxygen can promote the healing of tooth socket with bio-oss bone substitution material. |
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