Study About The Treatment Of Periodontitis With Ornidazole Hydrogel

Objectives and Background:Periodontitis is an oral disease characterized by gingival bleeding,loss of periodontal soft tissue attachment,periodontal pocket formation,and alveolar bone loss.Severe periodontitis will result in tooth loss and further alveolar bone loss,which will make subsequent repair difficult and increase the risk of periimplant inflammation.Dental plaque is the initiator of periodontitis,and the host's abnormal defense against bacterial pathogens also plays an important role in the progression of periodontitis.Porphyromonas gingivalis is considered to be a periodontal pathogen found in the oral cavity of patients with invasive periodontitis,chronic periodontitis and acute periodontitis.At present,mechanical debridement and systemic and local use of drugs,such as brushing,scraping,cleaning,drug treatment to eliminate bacteria.Mechanical debridement can usually improve periodontal,however,some parts of the effect can not achieve the desired.Pathogenic species such as porphyromonas gingivalis are persistent and can prolong chronic inflammation and aggravate the progression of attachment loss.The treatment of periodontal disease of teeth should also pay attention to the eradication or inhibition of pathogenic microorganisms in periodontal pocket.In these cases,systemic or local antibiotic therapy can help improve mechanical debridement clinical outcomes.Systemic use of ornidazole is oneof the options for the treatment of periodontal disease.This bactericidal drug can destroy the DNA of bacteria and lead to death.It is also effective for porphyromonas gingivalis.However,due to the widespread use of these antimicrobial agents,a large number of bacteria have adapted to them,resulting in drug resistance,resulting in a decrease in the effectiveness of antimicrobial agents.These resistant bacteria pose a growing threat to global public health.While local provision of antimicrobials can cause higher local drug concentrations and reduce dose-related systemic toxicity,and also reduce the probability of bacterial resistance.Hydrogel is a polymer network system,soft nature,can maintain a certain shape,with high water content,can load other materials and drugs.In recent years,more and more studies have produced hydrogels with various excellent properties.Therefore,this study will prepare a drug-loaded sustained-release hydrogel with good biocompatibility and mechanical properties and load ornidazole to explore the material characterization,cytotoxicity,bacteriostatic activity and effect on the treatment of periodontitis.Methods:Hydrogels were prepared from n-carboxyethyl chitosan(CEC),Hyaluronic acid-aldehyde(HA-ALD)and Adipate acid dihydrazided(ADH),in which ornidazole was loaded.Self-repair,injectable and rheological properties of hydrogels were observed and determined.Scanning its microscopic morphology by scanning electron microscopy to observe and measure the void size.Hydrogel loaded with ornidazole was placed in the PBS to test its ornidazole release.The effects of hydrogels on the growth of mouse osteogenic cells(MC3T3-E1)were detected using CCK8.The antibacterial properties of hydrogels were determined by bacteriostatic ringexperiments.The effect of on bacterial biofilm formation was determined by using crystalline violet staining.Rat periodontitis model was established by ligation and inoculation of porphyromonas gingivalis,after successful modeling,it was divided into periodontitis group,periodontitis hydrogel group,and periodontitis ornidazole hydrogel group.The latter 2 groups were given the corresponding hydrogel at the periodontal pocket and injected into the maxillary first molar periodontal pocket until 4 weeks after operation.Rats were killed and the maxilla was taken as the specimen,the distance from the top of the alveolar ridge alveolar bone crest(ABC)to the cemento-enamel junction(CEJ)of the first molar of each group of samples was observed and measured.The mean value was the sample results,and the statistical analysis group difference.HE staining was used to observe the morphological changes of periodontal tissue sections in rats,and to judge the gingival inflammatory state,fibrous connective tissue changes and alveolar bone tissue changes.Results:Ornidazole hydrogel with good injectable,self-repairing properties.Scanning electron microscopy shows that the ornidazole hydrogel has a loose and porous structure and uniform pore size between 100-200 nm.And can maintain the release of ornidazole for 7 days,with sudden release on the first day and high concentration on the first 3 days.After mixed culture of MC3T3 cells with ornidazole hydrogel,the cytotoxicity experiment showed that the cells grew well.Antimicrobial experiments showed that the group containing ornidazole hydrogel had obvious bacteriostatic ring,and the amount of bacterial biofilm was 10 times lower than that of the blank control group.The gross observation showed that the bleeding index decreasedobviously after the local application of ornidazole hydrogel,the gingival morphology color was better,and the texture was tough.The alveolar bone height of ornidazole hydrogel group was significantly higher than that of periodontitis group and blank hydrogel group.Histological evaluation showed that the repair and regeneration of alveolar bone and fibrous connective tissue and the inflammation of gingival tissue were significantly improved after local application of ornidazole hydrogel in periodontitis rats.Conclusions:1.Ornidazole hydrogel is a periodontal drug sustained release system with injectable,self-repairing and good pore structure.2.Ornidazole hydrogel can effectively inhibit the growth of porphyromonas gingivalis and reduce bacterial biofilm formation.3.Ornidazole hydrogel can inhibit periodontal tissue inflammation and promote periodontal tissue repair and regeneration in rats.