Dental patient preferences and choice in clinical decision-making.

In economics, the concept of utility refers to the strength of customer preference. In health care assessment, the visual analogue scale (VAS), the standard gamble, and the time trade-off are used to measure health state utilities. These utility measurements play a key role in promoting shared decision-making in dental care. Individual preference, however, is complex and dynamic. The purpose of this study was to investigate the relationship between patient preference and educational intervention in the field of dental health. The data were collected by distributing questionnaires to employees of two companies in Japan. Participants were aged 18-65 years and consisted of 111 males and 93 females (204 in total). One company (Group A) had a dental program of annual check-ups and health education in the workplace, while the other company (Group B) had no such program. Statistical analyses were performed with the t-test and Chi-square test. The questionnaire items were designed to determine: (1) oral health-related quality of life, (2) dental health state utilities (using VAS), and (3) time trade-off for regular dental check-ups. The percentage of respondents in both groups who were satisfied with chewing function, appearance of teeth, and social function ranged from 23.1 to 42.4%. There were no significant differences between groups A and B in the VAS of decayed, filled, and missing teeth. The VAS of gum bleeding was 42.8 in Group A and 51.3 in Group B (p<0.05). The percentage of persons having a regular dental check-up every three months was 34.1 and 31.3% in Groups A and B respectively. These results suggest that low preference results from lack of opportunity or utilization of dental care in the worksite. Ascertaining the factors involved in patient preference may have significant potential benefits in shared decision-making.

Factors associated with root surface caries in elderly.

The purpose of this study was to determine the risk factors for root surface caries in the elderly and to evaluate the factors associated with gingival recession, one of the main risk factors for root surface caries. A total of 153 elderly people (35 men, 118 women) aged between 60 and 94 years (73.5+/-7.5 years) were surveyed. All participants were relatively healthy elderly who did not need special care in their daily lives. The survey was conducted in Chiba prefecture, Japan, and oral examinations and a questionnaire with face-to-face interviews were also carried out. Correlation analysis revealed that number of present teeth (p<0.001), gingival recession (p<0.001), bleeding on probing (p<0.001) and presence or absence of dentures (p<0.05) were significantly correlated with number of root surface caries. Stepwise multiple linear regression analysis for root surface caries revealed that the risk factors for increasing numbers of teeth with root surface caries were number of teeth with gingival recession (p<0.0001), bleeding on probing (p=0.0017) and self-reported dry mouth (p=0.0454). Sex (p<0.05), number of present teeth (p<0.001), bleeding on probing (p<0.01), the presence or absence of systemic disease (p<0.01), dentures (p<0.01), drinking alcohol (p<0.01) and smoking (p<0.01) were significantly correlated with amount of gingival recession by correlation analysis. Moreover, the risk factors for increasing number of teeth with gingival recession were living in an institution (p=0.0244), number of present teeth (p<0.0001) and smoking (p=0.0037), as determined by stepwise multiple linear regression analysis for gingival recession.

Reduction of Streptococcus mutans adherence and dental biofilm formation by surface treatment with phosphorylated polyethylene glycol.

Initial attachment of the cariogenic Streptococcus mutans onto dental enamel is largely promoted by the adsorption of specific salivary proteins on enamel surface. Some phosphorylated salivary proteins were found to reduce S. mutans adhesion by competitively inhibiting the adsorption of S. mutans-binding salivary glycoproteins to hydroxyapatite (HA). The aim of this study was to develop antiadherence compounds for preventing dental biofilm development. We synthesized phosphorylated polyethylene glycol (PEG) derivatives and examined the possibility of surface pretreatment with them for preventing S. mutans adhesion in vitro and dental biofilm formation in vivo. Pretreatment of the HA surface with methacryloyloxydecyl phosphate (MDP)-PEG prior to saliva incubation hydrophilized the surface and thereby reduced salivary protein adsorption and saliva-promoted bacterial attachment to HA. However, when MDP-PEG was added to the saliva-pretreated HA (S-HA) surface, its inhibitory effect on bacterial binding was completely diminished. S. mutans adhesion onto S-HA was successfully reduced by treatment of the surface with pyrophosphate (PP), which desorbs salivary components from S-HA. Treatment of S-HA surfaces with MDP-PEG plus PP completely inhibited saliva-promoted S. mutans adhesion even when followed by additional saliva treatment. Finally, mouthwash with MDP-PEG plus PP prevented de novo biofilm development after thorough teeth cleaning in humans compared to either water or PP alone. We conclude that MDP-PEG plus PP has the potential for use as an antiadherence agent that prevents dental biofilm development.

Percentile curves for present teeth in smokers and non-smokers in an adult male population.

The purpose of this study was to obtain percentile curves for present teeth in smokers and non-smokers for use in oral health education. Dental examinations were carried out by two dentists. The number of present teeth in each subject was counted, excluding the third molars. Subjects consisted of 2,283 men aged between 25 and 54 years enrolled in the health insurance union of a bank in Yokohama, Japan. Each subject completed a questionnaire on smoking habits and number of cigarettes smoked. They were classified into two groups: smokers and non-smokers. The mean number of present teeth in both groups was compared with the Mann-Whitney's U test. Smokers had fewer teeth than non-smokers in all age groups (p<0.05). At the age of 50, the 50th percentile for present teeth was 26 for smokers and 27 for non-smokers. However, the 3rd percentile for smokers' present teeth was 20.5 at 40 years of age and 14 at 50 years of age, while for non-smokers it was 22.5 at 40 years of age and 19 at 50 years of age. The 3rd percentile curve for smokers' present teeth decreased in those aged 45 years and over. The percentile curves in this analysis showed a clear difference between the two groups. These data should be made available for use in adult oral health education.

Fluoride analysis of foods for infants and estimation of daily fluoride intake.

The mean daily fluoride intake in infants was estimated on the basis of their intake of commercial foods for infants in Japan and evaluated in order to establish the effectiveness and safety criteria for water fluoridation, which is practiced as a preventive measure for dental caries suitable in life stages from children to the elderly. Based upon the intakes of foods for infants, the mean daily fluoride intake was estimated to be 0.166 mg in infants aged 3-4 months, 0.202 mg in those aged 5-6 months, and 0.266 mg in those aged 7-8 months. The mean daily fluoride intake per kg of body weight at these ages was in the range of 0.023-0.029 mg/kg, which was about half of the standard daily fluoride intake for infants and children advocated by Ophaug et al., as 0.05-0.07 mg/kg. From our results, the daily fluoride intake of infants from foods in Japan is estimated to be equivalent to or lower than the values of previous reports in non-fluoridated areas. Consequently, our data support the argument that water fluoridation and the appropriate use of fluoride for dental caries prevention in Japan are needed on the basis of scientific criteria in terms of fluoride exposure related to food intake during tooth formation.

Comparison of short-term in vitro fluoride release and recharge from four different types of pit-and-fissure sealants.

OBJECTIVE: The purpose of this in vitro study was to assess the effects of four commercial fluoride-containing pit-and-fissure sealants on caries prevention. MATERIALS AND METHODS: Four sealants containing fluoride, Fuji III, Fuji III LC (GC Co., Tokyo), Teethmate F-1 (Kuraray Medical Co., Osaka) and Helioseal F (Vivadent Co., Liechtenstein) were used to investigate fluoride release and recharge. Disk-shaped specimens prepared from each material were immersed in distilled water at a temperature of 37 degrees C. After seven days, acidulated phosphate fluoride solution (APF) was applied to each specimen, and it was then again immersed in distilled water for 14 days. We then determined how much fluoride had been released into the immersing water. Fuji III LC was used with APF solution to investigate the fluoride uptake. RESULTS: Fuji III had the highest fluoride release, and Fuji III LC had the highest fluoride recharge. Helioseal F and Teethmate F-1 had almost no fluoride recharge. Fuji III LC/APF had a higher fluoride uptake to enamel than Fuji III LC. CONCLUSIONS: These results suggest that GIC-sealants in the oral cavity can serve as a fluoride reservoir and contribute to retaining a low fluoride level in oral fluids, thereby preventing caries.

Effect of chitosan rinsing on reduction of dental plaque formation.

The purpose of the present study was to investigate whether the use of a chitosan mouthrinse could be efficacious in reducing plaque and saliva mutans streptococci level. A randomized crossover clinical trial was performed to evaluate the effect of a rinse with 0.5% chitosan for 14 days on plaque formation and mutans streptococci counts in saliva. Twenty-four subjects were randomly assigned either the chitosan rinse or a placebo rinse in addition to their usual oral hygiene procedures. Following the baseline examination, each subject was given a prophylaxis. They were instructed to rinse with 20 ml of the mouthrinse twice daily for 30 seconds. Plaque scores were measured after a 14-day rinsing period, and mutans streptococci counts in saliva were also determined at the start and the end of the each rinsing period. The procedures were repeated with the alternate rinse after a 14-day washout period. Rinsing with 0.5% chitosan was significantly more effective in plaque reduction using the Quigley & Hein Index (chitosan: 1.44, placebo: 1.62, p < 0.001) and Plaque Severity Index (chitosan: 0.138, placebo: 0.186, p = 0.003). The mutans streptococci count in saliva was less after the chitosan rinsing (chi 2 cal = 13.51, p = 0.035) than placebo rinsing. In conclusion, the chitosan rinsing was effective in reducing plaque formation and counts of salivary mutans streptococci after a 14-day rinsing period. These results would appear to warrant further investigation into the potential value of chitosan as an effective anti-plaque agent for use in oral hygiene products.

Effect of molecular mass and degree of deacetylation of chitosan on adsorption of Streptococcus sobrinus 6715 to saliva treated hydroxyapatite.

We evaluated the influence of molecular mass and degree of deacetylation of chitosan on the adsorption of Streptococcus sobrinus 6715 to saliva-treated hydroxyapatite (S-HA) by measuring the optical density of the bacterial cell suspensions released from saliva-treated hydroxyapatite. Twenty-five chitosan samples with different molecular masses (0.8-6 kDa) and degrees of deacetylation (10-95%) were prepared for the study. We found that the inhibition of adsorption of S. sobrinus 6715 to S-HA correlated positively with the molecular mass of chitosan (R = 0.876) and that the optimal degree of deacetylation was 50-60% for maximum inhibition of bacterial binding to S-HA. We also examined the effect of chitosan on zeta potentials of the oral bacteria and their surface hydrophobicities. It was observed that chitosan reduced the magnitude of the zeta potential and surface hydrophobicities of the oral bacteria. Thus, the results demonstrated that chitosan with a molecular mass of 5-6 kDa and a degree of deacetylation of 50-60% might have the potential to act as an effective anti-plaque agent because of its polycationic properties.

Changes and equalization in hearing level induced by dental treatment and instruction in bilaterally equalized chewing: a clinical report.

Hearing problems such as hearing loss and susurrus aurium are said to improve with occlusal treatment, but few objective clinical reports have been published in the dental field. We looked at the effect of occlusal treatment and chewing instruction on hearing ability in five patients who had an occlusal disorder and the unilateral chewing habit. The following results were obtained: 1. Unilateral chewing due to occlusal disorder may cause differences in hearing ability between the right and left sides (Cases 1, 2 and 3). 2. A reduction in the vertical dimension of occlusion is considered to be one of the factors that cause a decrease in hearing ability (Cases 4 and 5). 3. In all cases, occlusal treatment and chewing instruction lead to a improvement in hearing and to equalizing of hearing ability between low and high frequencies. These clinical findings indicate that there is a relationship between changes in hearing ability and oral function.