• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.43-53
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• 1998

Dental caries is induced by organic acids produced by oral bacteria. In order to prevent dental caries, therefore, it is essential to maintain neutral pH in the oral cavity. Urea plays a major role in oral pH homeostasis. Urea is hydrolyzed by bacterial ureases to ammonia, causing a pH elevation. Streptococcus salivarius has been shown to be a major contribution to oral ureolysis. Synthesis of urease by S. salivarius appears to be constituitive, but can be greatly enhanced by low pH. It is, therefore, conceivable that ureolytic activity of S. salivarius from a carious lesion is greater than that of the bacterium from a healthy tooth. In the present study, urease activity of S. salivarius isolates from dental plaque of carious lesions was compared with that of the isolates from plaques of the teeth and the dorsum of the tongue; 45 S. salivarius strains were isofated from carious lesions(>C2) of 21 individuals with dental caries and 30 strains from 10 individuals without dental caries. The results were as follows: 1. All the 21 individuals with dental caries harbored ureolytic S. salivarius whereas 3 of 13 individuals without dental caries harbored non-ureolytic strains of S. salivarius. 2. All the 45 S. saliuarius isolates from carious lesions showed urease activity. In contrast, of 30 isolates from individuals without dental caries, 17 isolates(56.7%) did not demonstrate urease activity, or if any, very little(<5${\mu}mol$/min/mg). 3. Urease activity of the isolates from carious lesions was greater than that of the isolates from individuals without dental caries : the urease activity ranged from 42 to $381{\mu}mol$/min/mg and from 0 to $208{\mu}mol$/min/mg, respectively. 4. At acid pH(5.5), the isolates which showed intermediate urease activity at pH 7.0 demonstrated even higher activity whereas the isolate with no or lower urease activity did not show any significant difference in their activity. However, the isolates with the greatest urease activity from both individuals with and without dental caries, exhibited a rather much lower urease activity at pH 5.5. The overall results suggest that isolates may have their own urease activity but the isolates exposed to chronic acidic environment of the carious lesion might elevate urease activity of S. salivarius, which in turn, might influence on survival of S. salivarius itself and other bacteria, establishing a new oral bacterial ecosystem.

• Journal of Korean society of Dental Hygiene
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• v.12 no.2
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• pp.365-377
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• 2012

Objectives : This research was conducted to determine the effect of the Visiting Oral Health Care Program by examining the oral health of the elderly women, who are the beneficiaries of this Visiting Oral Care Program. Methods : This research was conducted from November of 2011 to February of 2012, in Chilgok-gun in the Kyeongbuk Province, South Korea. One hundred and twenty five (125) elderly women among the beneficiaries of the Visiting Oral Care Program within the area were randomly selected for the research. The research subjects would regularly visit the area senior citizen center, and they were divided into two groups, with 64 of them belonging to a control group, and the rest (61 people) belonged to a intervention group. The research subjects were examined for their dental health condition, and we investigated the effect of the Visiting Oral Care Program through this research. Results : 1. When they were asked about how many times they wash their dentures, the majority of the control group, 57.4% of them answered that they do it "once" a day. The majority of the intervention group answered "more than 3 times", with 35.2% of group mentioning that they wash their dentures more than 3 times a day(p<.001). 2. When the research subjects were asked to scale their overall quality of life before and after the Visiting Oral Care Program, the control group had rated 49.3 before the Service and 56.8 after the Service (p<.01), and scores for the individual factors to determine the overall quality of life has significantly improved as well (p<.01, p<.01, p<.01, p<.01, p<.01, p<.01, p<.01). 3. The oral hygiene condition after the Visiting Oral Care Program has shown improvement as well. The control group scored 64.2 for the severity of the symptoms of dental plaque before the dental care, and scored 46.8 after the dental care (p<0.1). The control group was diagnosed for the symptoms of coated tongue, and the severity of the symptoms were scaled as 3.7 before the Program and 2.0 after the Program (p<.01). Furthermore, the overall functionality of the oral cavity was improved as well. The control group showed 1.0 time increase in repetitive voluntary swallowing test (p<0.1), increased amount of sublingual saliva from 0.8mm to 1.4mm, and from 1.6mm to 2.0mm in dorsum linguae(p<0.1). Also, the control group showed an improvement in mouth opening as well, increased from 3.9 to 4.0cm after the oral care program (p<.05). When compared the result with the examination after the Visiting Oral Care Program, the two groups showed a significant difference with the control group showing a significant improvement compared to the intervention group(p<.01, p<.01, p<.01, p<.01, p<.05). 4. The correlation between the dental hygiene condition and the functionality of oral was made for the result of examining the beneficiaries for Visiting Oral Care Program. The amount of saliva showed a negative correlation with the severity of dental plaque (p<.05), and a positive correlation with the repetitive voluntary swallowing count (p<0.1). Also, mouth opening showed a positive correlation with repetitive voluntary swallowing count (p<.05). Conclusions : After the Visiting Orall Care Program, the beneficiaries of the program experienced improvement in their quality of life related to oral health, overall oral hygiene and functionality of oral.