| Summary: | 碩士 === 高雄醫學大學 === 口腔衛生科學研究所碩士班 === 93 === Abstract
Background：
Dental caries is a complex disease affecting many people around the world.Among the many causes of dental caries,saliva is the most important physiological factor.Saliva has many anti-caries properties.that protect the tooth surface against caries development.Salivary flow rate, buffering capacity, antimicrobial activity,clearance from the oral cavity and immune function all interact to inhibit or reverse demineralization of exposed tooth surfaces. Oral microflora also affect caries development.In our study,we checked salivary flow rate,buffering capacity（salivary pH value）and salivary fluoride concentration.We also tested oral microflora (including streptococci, lactobacilli and candida).Finally we discussed the association between these factors and the DMFT index.
Study Objective：
1.To study the distribution of salivary factors and oral microflora
2.To study the association between salivary factors
3.To study the association between salivary factors,oral microflora and the DMFT index
4.To find the more important factors that cause caries
Methods：
The present investigation included 223 6th grade children(12-yr-old) attending Kaohsiung elementary school.The children were examined clinically for caries and the results were recorded. Saliva sample were collected for laboratory tests.We recorded salivary flow rate ( ml/min), salivary pH value, salivary fluoride concentration (ppm) and the presence of oral microflora.Survival analysis was performed using correlation coefficient, paired-t test,ANOVA and logistic linear regression.JMP statistical software was used for data management and for statistical tests.
Results：
In this study,unstimulated salivary flow rate was 0.45±0.30 ml/min,stimulated salivary flow rate was 0.64±0.37ml/min；unstimulated salivary pH value was 7.26±0.40 and stimulated salivary pH value was 7.81± 0.31.Salivary fluoride concentration was 0.0564±0.0718 ppm and the DMFT index was 2.73±2.42.Children who had more oral microflora had a higher DMFT and D index (P<0.0001), a lower salivary pH value (P<0.0001) and a lower salivary flow rate.Children who had a higher DMFT index(＞3) had a lower salivary flow rate and salivary pH value. The more important factors causing caries in this study were the streptococci and lactobacilli counts.
Conclusion：
We found stimulated salivary flow rates were higher than unstimulated salivary flow rates and stimulated salivary pH values were higher than unstimulated salivary pH values.Children who had more oral microflora had a higher DMFT index and a lower salivary flow rate and salivary pH value.Salivary factors and oral microflora play an important role in causing caries and we should employ many preventive measures. Besides oral health education,the change of dietary habits and the use of fluorides,, we suggest further study of salivary factors and oral microflora. Better understanding of oral physiological factors will result in better caries prevention.
Key words:saliva, oral microflora, DMFT index
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