| Objective:In oral clinical treatment,bone insufficiency of alveolar bone often occurs,which will affect the follow-up conventional restoration treatment and implant restoration treatment.Preservation of the alveolar socket after tooth extraction can effectively maintain the alveolar bone capacity,provide favorable conditions for the restoration treatment,and ensure a good restoration effect.In alveolar socket preservation surgery and bone augmentation surgery,the participation of bone graft materials is required.Dentin particles are widely recognized as bone graft regeneration materials,but whether particles with different degrees of decalcification can have a positive effect on promoting bone remodeling is not clear.This experiment compares the osteogenesis effect of 4 different dentin degrees of decalcification in the preservation of the alveolar socket,and provides a reference for the selection of clinical graft materials.Materials and methods:1.Preparation of dentin granules: 6 1-year-old beagles were selected,the 3rd and 4th premolars of each experimental dog were extracted,and enamel,cementum and pulp were removed by grinding machine.The dentin particles with a diameter of 500-800 μm were crushed and screened,decalcified in 2% nitric acid solution,divided into group A:not decalcified dentin particles;Group B: dentin granules with 1min decalcification;Dentine granules decalcified for 10 min in group C and completely decalcified granules in group D;Group E was blank control group.Alcohol disinfection and saline rinse for backup use.2.Operation process: The experimental dog was under general anesthesia,the flap was incised in the premolar area along the gingival sulcus,and the third and fourth premolars were extracted to prepare dentin particles.The prepared particles were randomly filled into the extraction sockets,tightly sutured,and antibiotics were injected to prevent infection after the operation.They were sacrificed 6 months later.3.Observation indicators: Gross observation implantable wound healing area,with or without infection status,implanted alveolar ridge whether significant absorption.CT observation of the general bone density transmission in the implantation area;non-decalcifying resin-embedded sections to observe the new bone and particle morphology;paraffin sections to observe the microscopic morphology of new bone and bone cells,histological measurement and analysis of the remaining particles,the rate of new bone formation and The bone cell density was compared by one-way analysis of variance with SPSS17.0 statistical software.When P<0.05,it is statistically significant.Results:1.General observation: 6 months after the operation,no obvious suppuration or infection was found.After the soft tissue was removed,the alveolar ridges were smooth in each group,and no obvious boundary between the old and the new bone.2.Observation of tissue morphology:CT:Visible in shallow different degrees of tooth extraction socket through projective,prompt tooth extraction sockets with new bone formation,more obvious in the dentin granule filling group,and the bone transmission at the alveolar ridge is lower,while the transmission at the end of the bone marrow cavity is higher.The blank group showed worse new bone morphology and more space in the alveolar fossa.Non-decalcified resin section: Under the microscope,loose and scattered irregular new bone was formed in the alveolar fossa of the blank group,and the top of alveolar ridge,buccal lingual side was incoherent.In the complete decalcified group,large dentin grains and irregular curved new bone were observed,and the top of alveolar ridge was consistent.Under the microscope of 1min decalcification group,small scattered dentin particles remained,new bone wrapped particles were connected with each other,and alveolar ridges were coherent;In the 10 min decalcification group,there were almost no residual particles,the new bone interwoven more closely,occupied a lot of space in the alveolar fossa,and the alveolar ridge reached a certain thickness.Decalcified groups see no particle residual,completely new bone more mature and orderly,but larger space between each other.Paraffin section: New bone trabeculae and small vessels appeared in alveolar fossae of each group to varying degrees.In the non-decalcified group,new bone grew in shape between grains and was in close contact with grains.The arrangement of bone cells was relatively concentrated and scattered,and large absorption lacunae were visible in grains,showing insect-like.In the 1min decalcification group,the granules were small and scattered,which were wrapped by new bone and occupied more space in the alveolar socket,and the bone cells were densely arranged and scattered.In the 10 min decalcification group,only a few grains were found,the new bone trabeculae occupied a larger space in the alveolar fossa,the osteocytes were more dispersed and orderly,and the unformed Hafers bone canal with calcareous lamellar deposits could be found.The complete decalcified group showed more mature bone,and the osteocytes were dispersed neatly,without any granular morphology,but there were more voids in the alveolar fossa.3.Histological measurement analysis:The remaining particle area of group A was 0.339±0.054mm2,group B was0.065±0.031mm2,group C was 0.008±0.002mm2,and group D was 0.There was statistical difference among all groups(P < 0.001).The proportion of new bone in alveolar fossa was 19.4±1.4% in group A,34.6±2.9% in group B,73.6±5.7% in group C,54.8±4.4% in group D and 9.6±2.1% in group blank,respectively.There was statistical difference among groups(P < 0.001).It indicated that the osteogenic effect of pellet filling group was better than that of blank control group.The osteogenic effect of 10 min decalcified dentin granules group was the best.Conclusion:1.It was found in this study that dentin granules can achieve good bone regeneration effect when used for the preservation of alveolar fossa.2.After 6 months of bone grafting,dentin granules with 10 min of decalcification had better effect on the preservation of alveolar socket than other groups. |
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