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Objective@#To investigate the mechanisms by which D-methionine (D-Met) eradicates Porphyromonas gingivalis biofilms by suppressing cyclic dimeric GMP (c-di-GMP) levels.@*Methods @#Cell viability, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured to determine the effective concentrations of D-Met, which were subsequently used in the following experiments. During the P. gingivalis biofilm formation inhibition experiment and the mature biofilm disassembly experiment, biofilm biomass, exopolysaccharide (EPS), biofilm morphology, integrity of the cell membrane, and the level of c-di-GMP were determined. @*Results @# D-Met < 40 mmol/L was biocompatible. During the biofilm formation inhibition and mature biofilm disassembly experiments, D-Met ≥ 20 mmol/L decreased the biofilm biomass and the production of EPS. SEM analysis showed that the extracellular matrix and bacterial density were drastically reduced by D-Met ≥ 20 mmol/L. TEM detection showed that 35 mmol/L D-Met ruptured the cell membrane during biofilm formation and increased the permeability of the cell membrane in the disassembly phase of mature biofilms. C-di-GMP levels decreased with increasing concentrations of D-Met in a concentration-dependent manner.@* Conclusion @# D-Met ≥ 20 mmol/L could eradicate P. gingivalis biofilms by suppressing c-di-GMP levels.
ABSTRACT
@#Implant dentures have become the main method for the treatment of dentition defects or complete edentulism. However, due to the lack of periodontal ligament and periodontal ligament proprioceptors, implant dentures have very limited cushioning and sensing capabilities and are prone to occlusal overload. As a risk factor for peri-implantitis, occlusal overload seriously threatens the stability and success rate of implant dentures. This paper reviews the occlusal overload of implant dentures, the causal relationship between occlusal overload and plaque biofilms in peri-implantitis, the mechanism by which occlusal overload promotes peri-implantitis, and the effect of reasonable clinical occlusal adjustment on healing. This review shows that occlusal overload is closely related to the occurrence of peri-implantitis. Occlusal overload can promote the process of peri-implantitis by increasing the release of inflammatory factors and mechanical transduction mechanisms. The intervention of the patients’ bad bite habits and occlusal adjustment can promote the healing of peri-implantitis. At present, there is no uniform standard ideal experimental model for occlusal overload. The phenomenon and mechanism of bone resorption around the implant caused by overload force still need further observation and research, which will help determine the intensity, direction and timing of occlusal loading to guide clinical occlusal adjustment.
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Objective@#To evaluate ten year changes in deciduous teeth health and oral health behavior aged 5 year old children in Hainan province (during the year of 2005-2015), to provide basis for oral health promotion among 5 year old children in Hainan province.@*Methods@#Through the comparison and analysis of the third and the fourth national oral health epidemiology survey,changes of dental caries prevalence rate, dietary habit, oral health behavior, and health seeking behavior were analyzed.@*Results@#The prevalence of dental caries in 2005 was 76.1%, 2015 was 82.3% which had significant difference(χ2=6.23，P<0.05), the percentage of consuming sugary food and sweet drinks every day in 2005 was 13.4% and 6.1%, which increased to 30.0% and 7.4% respectively in 2015. The percentage of drinking milk and yoghurt with sugar was 47.6%, which decreased 36.5% in 2015 (χ2=12.76，P<0.05), the percentage of consuming sugary food and sweet drinks before going to bed in 2005 was17.8%, which decreased to 13.3% in 2015 (χ2=32.27，P<0.05). The percentage of brushing the teeth two or more times a day was 16.9%, which increased to 24.2% in 2015(χ2=20.50，P<0.05). The percentage of using fluoridated toothpaste decreased from 31.7% (2005) to 7.4% (2015) (χ2=229.13，P<0.05). No need to treatment for baby teeth and afraid of pain among children were the main reason for no health-seeking among parents which children of dental health problems,which deffered significantly between 2005 and 2015(χ2=6.05，9.34，P<0.05).@*Conclusion@#Children’s oral health behavior improved, while eating habits fluoridated toothpaste usage and health seeking behavior remain poor.Health education on child oral health should be strengthened.
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Objective@#To evaluate the changes of oral health status and oral health behavior among 12 year old children in Hainan province during 2005-2015, to provide basis for child oral disease prevention.@*Methods@#Through the third and fourth national oral health epidemiology survey, changes in dental caries prevalence rate, dietary habit, oral health behavior, medical care in 12 year old chirdren were analyzed.@*Results@#The percentage of dental caries in permanent, gingival blleeding, dental calculus of 12 year old chirdren in 2005 was 49.9%, 63.2%, 31.5% respectively, which 57.0%, 46.8%, 39.5% respectively in 2015( χ 2=6.78, 36.78, 9.45, P<0.05). The percentage of sugary snacks,drink and milk consumption every day in 2005 was 31.0%, 13.1%, 21.8% respectively, which increased to 40.3%, 27.5%, 30.8% in 2015(χ2=11.53, 38.76, 12.73, P<0.05). 49.3% children had a toothache in 2005, which increased 58.8% in 2015(χ2=23.43, P<0.05).@*Conclusion@#The prevalence of dental caries in permanent teeth of 12 year old children in Hainan was high, while eating habits was poor and oral health behavior was showed significant improvement. Oral health education for 12 year old should be strengthened.
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Abstract Purpose: To investigate the effect of oxymatrine on periodontitis in rats and related mechanism. Methods: Ninety SD rats were divided into control, model, 10, 20 and 40 mg/kg oxymatrine and tinidazole groups. The periodontitis model was established in later 5 groups. The 10, 20 and 40 mg/kg oxymatrine groups were intragastrically administrated with 10, 20 and 40 mg/kg oxymatrine, respectively. The tinidazole group was intragastrically administrated with 100 mg/kg tinidazole. The treatment duration was 4 weeks. The tooth mobility, gingival and plaque indexes, serum inflammatory factor levels and gingival tissue matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP) protein levels were detected. Results: After treatment, compared with model group, in 40 mg/kg oxymatrine group the rat general conditions were obviously improved, the tooth mobility, gingival index and plaque index were significantly decreased (P<0.05), the serum tumor necrosis factor-α, interleukin-1β and prostaglandin E2 levels were significantly decreased (P<0.05), the MMP-2 and MMP-9 protein levels were significantly decreased (P<0.05), and the TIMP-2 protein level was significantly increased (P<0.05). Conclusions: Oxymatrine can alleviate the experimental periodontitis in rats. The mechanism may be related to its inhibiting inflammatory factor secretion and regulating MMPs/TIMP protein expression.