Using a dental questionnaire on a web page on the Internet, we investigated whether different tendencies that appeared among the Internet users were due to individual variations in characteristics. The questionnaire was scripted by HTML and the answers were sent with "Form Mail". A total of 2,858 replies were received. We counted and analyzed 2,637 answers and excluded -repeat replies and invalid questionnaires. The ratios of the answers of 15 questions were calculated and the results showed that many users practiced preventive behavior and were conscious of dental health. Bias due to individual characteristics such as age, sex, profession, area of residence, the size of the city were investigated using logistic regression analysis. Eleven of the 15 regression formulas derived were significant in terms of log-likelihood and the "Hosmer and Lemeshow goodness of fit test", and attributes except for "the size of the city" had significant partial regression coefficients. The results suggested that attributes caused different tendencies to the same question. Thus, the web page questionnaire was useful for dental research by comparing different attributes.
This study investigated the relationship between aging and the number of missing teeth in Japanese females. A simulation technique has been widely used to investigate real-life process and to obtain an accurate prediction with a mathematical model. In this study, we applied the least square method for those two relationships. Suitable polynomial functions were found. Comparisons of coefficients of determination of those functions, the largest error was found in the polynomial function of 1981, but it was under 2 percent. These functions are suitable for simulating tooth-loss in females. These functions differentiate easily, and the rate of change in tooth-loss can be calculated. This rate of change in tooth-loss changed with the era and aging, but it is an important coefficient to calculate the prediction value for future tooth loss. To calculate future tooth loss, it is possible to use the principle of difference equation. These results were very useful for field workers in dentistry, researchers who work in the community.
The aim of this study was to determine the reproducibility of dental health questionnaires placed on a web page on the Internet using a two part investigation. In the first part of this study, reproducibility was investigated for a 5 month period which proved that the answers given at the start of the 5 month period reappeared 5 month later. In the second part of this study, two different questionnaires with some similar questions were investigated for simultaneous reproducibility. The results were as follows ; 1. In the first part of the study, reproducibility was noted for oral and dental hygienic cleaning habits, satisfaction of treatment, attitude toward treatment policy and oral hygienic cleaning habits, and the condition and use of oral dental cleaning equipment. 2 . Many factors influenced a decrease in reproducibility. Question with low reproducibility were thought to be the action taken by the guidance given and awareness of prevention and cure. 3 . In the second part of this study, reproducibility influenced by oral and dental hygienic cleaning habits, and the condition and use of oral dental cleaning equipment. We concluded that Internet investigations had good reproducibility and are available as one of the methods for dental research.
The aim of this study was to evaluate the practicality of airborne bacteria management using multiple regression equation by environmental factors in a dental hospital. The environmental factors measured were : temperature, humidity, air flow, number of person, number of opened windows, number of operating air-conditioner outlets, outdoor temperature, outdoor humidity and outdoor air flow, and airborne bacterial colonies (floating airborne bacterial colonies by the SY method ; dropping airborne bacteria using Koch's method). Measurements were taken in mid-sized clinics (orthodontics, pedodontics) in 1990, and in large clinics (restoration, prosthetics) in 1991 at Asahi University Dental Hospital. Multiple regression equations were used to predict the number of floating airborne bacterial colonies and four years later, in 1994 and 1995, respectively, the predictive value of the equations was evaluated by substituting the measured values of environmental factors into the original equations. Differences in environmental factors and airborne bacterial colonies (t〜test), the effectiveness in predicting the values of floating airborne bacteria using the multiple regression equations (R2, R and F) and, the practicality of managing airborne bacteria using predicted values by the multiple regression equations (sensitivity and specificity) were evaluated. The threshold limit value of airborne bacteria was 0.2 CPU/l. Our findings showed : 1. Differences in environmental factors were noted in each dental clinic after four years. The number of floating airborne bacterial colonies had reduced in mid-sized clinics in 1994, but the number of dropping airborne bacterial colonies had increased in 1995 in large clinics. 2. The multiple regression equations were useful to predict the levels of floating airborne bacterial colonies. 3 . In all clinics, the sensitivity was greater than 60%. The highest positive predictive value was 70%. Based on these findings, we concluded that multiple regression equations using environmental factors is available for airborne bacterial management.
Several reports indicated that selection bias due to non-participation if targeted subjects were only participants in dental examination with a low response rate. Consequently, in the fourth survey of dental disease in Niigata Prefecture, the conventional search procedure which targeted only participants in a dental examination was changed to a procedure distributes the questionnaire to all subjects of the survey before dental examination. This paper evaluate this new method by comparing the response rate of participants in a dental examination to the questionnaire response rate and the characteristics of participants in the dental examination to those of non- participants by questionnaire. We selected 23 areas by allocating 1-2 areas to each prefectural health center. Total subjects of this survey were 3,561 people living in these areas excluding individuals 0 years old. The response rate of the dental examination was low (35.3%) with large differences in age and sex. The response rate of the questionnaire was high (83.2%) with small differences in age and sex. Self-estimated numbers of present teeth of participants in dental examinaion were higher than those of non-participants among 60-79-year-olds indicating that numbers of remaining teeth in the elderly was over-estimated when the subjects targeted consisted only of participants in dental examination when the response rate of dental examination was low as in this survey. Comparison of questionnaire responses between participants in the dental examination and non-participants showed that participants had more subjective oral symptoms, visited dental clinics earlier and had undergone scaling more often than non-participants. In conclusion, the new method adopted in this survey was considered useful for describing the community health picture correctly.
In this study we collected baseline data on the occurrence of first tooth loss in an adult population. Dental examinations were performed in 1992 and 1997 for 1,882 males and 974 females who underwent both dental examinations. Data were collected from subjects with one missing tooth in 1997 and no missing teeth in 1992. Subjects with the loss of one tooth were classified by type of tooth, gender and age-group. Statistical analysis of these data was performed with the chi-square test. And the results were as follows I 102 males and 45 females lost one tooth ', among the males, the distribution by tooth-type was lower-second-molar 15.7% and lower-first-molar 14.7% ; among females, the distribution of lower-first-molar loss was 31.1% and upper-first-molar was 11.0% ; females had a significantly higher rate of lower-first-molar tooth loss (p < 0.05) than males ; among males, the 20-34 age group had a higher rate of upper-second-premolar loss and a lower rate of lower first and second molar loss than the 35-49 age group. These findings indicated that oral health indicators using the occurrence of first tooth loss may be useful health information in adult populations.
The purpose of this study was to evaluate the three-year incidence of and risk predictors for tooth loss in community-dwelling adults. The subjects were 269 (128 males, 141 females) dentate adults living in a town in Niigata Prefecture who underwent oral examinations in both 1997 (baseline examination) and 2000 (follow-up examination). The follow-up rate was 37.2%. The mean age at baseline was 60.6 (SD = 12.8). A multiple-logistic regression model was used to quantify tooth-specific and person-level risk predictors for tooth loss using variables of the oral examination and questionnaire at baseline. The three-year incidence of tooth loss was 4.9% at tooth-level, 48% at person-level. The mean number of missing teeth per year was 0.33. The results of person-level multiple logistic regression analysis showed that tooth loss was more common in people with 10-27 present teeth, decayed teeth, oral symptoms, history of dental visit within a year and no habit of using an interdental brush or dental floss. Tooth-level multiple logistic regression analysis showed that the incidence of tooth loss was higher in wisdom teeth, decayed teeth, crowned teeth, abutment teeth in bridges and teeth with mobility.
I This study assessed the dental attendance behavior of bank employees to determine whether there was any the difference by age-group or gender. The subjects were 474 males aged from 25-64 yrs and 129 females aged from 25-44 yrs. The self-reported questionnaire was "Are you a patient even when you are experiencing an oral problem ?" Statistical analysis of these data was performed with the chi-square test. The results were as follows ', The proportion of persons who were usually patients without dental visits decreased with advancing age-group among males, showing the lowest score of 34.5% among 55-64 yrs. The most common reason for not seeking treatment was "too busy". The proportion of persons who indicated that they were too busy was 26.3% among subjects aged 55-64 yrs (p < 0.05). The proportion of persons responding "to be patient" was lower among 35-44 yr-olds than among 25-34 yr-olds for females. However, among 35-44 yr-olds, the proportion of persons responding "too busy to be patient" was higher than that among 25-34 yr-olds (p < 0.05). Among 25-34 yr-olds, the rate was 52.8% among males and 31.8% (p < 0.05) among females. These results suggest that it is necessary to give individual health instruction and adequate oral information to office workers.
We have cloned, sequenced, and expressed the gene encoding a pyrophosphate (PPi)-dependent-phosphofructokinase (PFK) (EC 188.8.131.52), designated PgPFK, from Porphyromonas gingivalis 381. The PgPFK gene consisted of 1,650 bp which coded for a protein of 550 amino acids with a calculated molecular mass of 61,044 Da. The deduced amino acid sequence of PgPFK exhibited a significant similarity to the 62 kDa PPi-PFKs from Borrelia burgdorferi and Treponema pallidum PFKβ-subunit. Most of the amino acid residues shown or assumed to be involved in substrate binding in other PPi-PFKs were conserved in PgPFK. Recombinant PgPFK was purified to homogeneity and characterized. The purified enzyme was found to be enzymatically active when it was expressed in Escherichia coli and was not regulated by classical effectors of ATP-dependent PFKs (ATP-PFKs) (EC 184.108.40.206) such as ATP, ADP, or fructose 2,6-bisphosphate like the known PPi-PFKs. Reverse transcriptase polymerase chain reaction analysis revealed that the PgPFK gene was expressed in P. gingivalis. Phylogenetic analysis showed that the long sequence type group of PPi-PFKs including PgPFK formed a coherent cluster like the ATP-PFK family. These results suggest that PgPFK is one of the most typical of PPi-PFK functioning in P. gingivalis. Moreover, it seems that this organism might not have any fructose 1,6-bisphosphatase (FBPase). From these results we propose that PgPFK serves as a FBPase in the gluconeogenic direction.
I This study investigated the remineralization enhancement effects of fluoride releasing restorative materials, namely, a resin modified glass ionomer cement (Fuji II LC, GC), a conventional glass ionomer cement (Fuji Ionomer ® Type II, GC) and a polyacid modified composite resin (Dyract ® , Dentsply). Root dentin blocks were prepared from root parts of bovine incisors and were demineralized by immersion in a lactic acid gel (pH 5) containing 6 wt% carboxymethyl-cellulose for 2 w. In the middle part of the demineralized surfaces, a standardized cylindrical cavity (diameter = 3 mm) was prepared. Subsequently, the cavities were filled with one of the above materials and the samples were immersed in a mineral solution (1.5 mM CaCl2, 0.9 mM KH2PO4, 20 mM Hepes, pH 7) for 14 d. The mineral distributions on dentin surfaces adjacent to the materials were assessed by transversal microradiography and videodensitometry. Compared with demineralized dentin samples which were immersed in a mineral solution containing 2 ppmF as NaF for 14 d, the samples filled with fluoride releasing restorative materials showed similar or higher mineral recovery. In conclusion, it was suggested that restoration of dentin cavities by fluoride releasing restorative materials can enhance remineralization of marginal tooth structure and may be effective for surrounding tooth protection.
This investigation compared human leukocyte antigen (HLA) class II allele frequencies between caries free and caries susceptible (DMFT ≧ 10) individuals. Examinations for dental caries were carried out with the use of a mirror and an explorer, according to World Health Organization criteria and methods. The total number of decayed, missing and filled permanent teeth (DMFT) was determined as the caries experience. The types of HLA-DRB1, -DRA1 and -DQB1 alleles were studied in 100 unrelated Japanese healthy young adults, aged 18-28 years, using polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) analysis. None of the HLA class II allele frequencies showed significant differences between the caries-free and caries-susceptible groups.
It has been reported that salivary secretion is highly affected by many systemic diseases, and that genetic polymorphism of HLA (human leukocyte antigen) class II gene influences susceptibility to these systemic diseases. Therefore, this study investigated the association of stimulated salivary flow rates with HLA class II allele frequencies, to determine whether HLA genotypes are related to affect salivary production. The types of HLA-DRB 1, -DQA 1 and -DQB 1 genes were studied in 105 unrelated healthy young Japanese adults (78 male, 27 female), aged 18-28 years (mean 20.5 years), using polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) analysis. The subjects were placed into three groups I ≦ 0.7 ml/min, 0.7-2.0 ml/min and ≦ 2.0 ml/min of salivary flow rates stimulated with paraffin wax. HLA-DRB 1*0901, -DQA 1 *0301 and -DQB 1*0303 alleles frequencies were significantly higher in the ≦ 0.7ml/min group compared with those in the ≦ 2.0 ml/min group. Contrarily, HLA-DRB 1*0802, HLA-DRB 1*1302, HLA-DRB 1*1501 and HLA-DQA 1*0102 allele frequencies were significantly higher in the ≦ 2.0 ml/min group compared with those in ≦ 0.7 ml/min. The results of the present study indicate that HLA class II alleles, or closely linked loci, may be involved in saliva secretion.