Alkali production in human dental plaque and saliva as predictor of caries risk

描述（由申请人提供）：龋病仍然是所有年龄组的高发流行疾病。体外研究和间接临床观察表明，口腔细菌的酶水解精氨酸和尿素产生氨，可以调节牙菌斑酸化，并可能抑制龋齿。本研究的目的是在临床水平上研究精氨酸脱亚胺酶（AD）和脲酶活性与龋齿状况的关系。我们假设没有龋齿的受试者斑块和/或唾液中的AD和脲酶活性明显高于龋齿活跃的受试者。研究人员将在牙菌斑和唾液样本中测量AD和脲酶的活性，这些样本来自无龋受试者、有龋经历的受试者和至少有4颗牙齿有活动性龋的受试者。特异性目的（SA） 1将确定牙菌斑、唾液AD和脲酶活性水平与人类受试者龋齿之间关系的大小和方向。SA 2将检查口腔样本中选定的主要产酸和产碱细菌种类数量与AD和脲酶活性水平之间的关系。sa3将研究AD和脲酶活性水平的预测因子。SA 1将通过病例对照研究来满足，SA 2将通过受试者的子样本来满足（10名最高，10名最低，10名斑块AD和脲酶水平中等）。SA3将通过收集患者的年龄、性别、种族、牙史、菌斑和口腔护理频率等信息来满足，并调查这些解释因素与AD和菌斑和唾液中脲酶活性水平的关系。如果本研究的结果支持AD和/或脲酶活性水平与成人龋齿之间的关联，所获得的知识将在资助期结束时应用于前瞻性队列研究的设计，该研究将确定这种关联是否为因果关系。如果AD和脲酶活性水平被证明可以预测成年人的龋齿风险，无论是单独的还是与其他风险因素结合，我们将把这种关系应用于开发新的方法，用于早期识别有龋齿风险的个体和制定龋齿预防策略。

DESCRIPTION (provided by applicant): Caries continues to be a prevalent disease with high incidence among all age groups. Ammonia production from the hydrolysis of arginine and urea by enzymes of oral bacteria moderates plaque acidification and may inhibit dental caries, as suggested by in vitro studies and indirect clinical observations. The objective of this study is to examine the relationship of arginine deiminase (AD) and urease activities with dental caries status at the clinical level. We hypothesize that AD and urease activities in plaque and/or saliva of caries free subjects is significantly higher than in caries active subjects. AD and urease activities will be measured in dental plaque and saliva samples from caries free subjects, caries experienced subjects, and subjects with at least 4 teeth with active caries. Specific Aim (SA) 1 will determine the magnitude and the direction of the association between plaque and saliva AD and urease activity levels with dental caries in human subjects. SA 2 will examine the relationship between AD and urease activity levels with the numbers of selected major acid-producing and alkali-producing bacterial species in the oral samples. SA 3 will investigate the predictors of AD and urease activity levels. SA 1 will be met through a case-control study and SA 2 will be met using a sub-sample of the subjects (10 with the highest, 10 with the lowest, and 10 with medium plaque AD and urease levels). SA3 will be met by gathering information on patient's age, gender, race, dental history, plaque, and frequency of oral care, and investigating the relationship of these explanatory factors to AD and urease activity levels in plaque and saliva. If the results of the present study support an association between AD and/or urease activity levels with dental caries in adults, the knowledge obtained will be applied to the design of a prospective cohort study at the end of the grant period, which will determine whether this association is a cause-and-effect one. If AD and urease activity levels are shown to be predictive of caries risk in adults, either alone or in combination with other risk factors, we will then apply this relationship to the development of novel approaches for early identification of individuals at risk to develop caries and for caries prevention strategies. PUBLIC HEALTH RELEVANCE: The proposed study will contribute to the development of novel methods for caries risk assessment and prevention, while providing a better understanding of unknown factors affecting caries risk.