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Biomedical subjects

Haruo Nakagaki

Publications and source records attributed to Haruo Nakagaki.

18 recordsLinked to original sources
PubMed2006

Behavioral factors to include in guidelines for lifelong oral healthiness: an observational study in Japanese adults.

BACKGROUND: The aim of this study was to determine which behavioral factors to include in guidelines for the Japanese public to achieve an acceptable level of oral healthiness. The objective was to determine the relationship between oral health related behaviors and symptoms related to oral disease and tooth loss in a Japanese adult community. METHODS: Oral health status and lifestyle were investigated in 777 people aged 20 years and older (390 men and 387 women). Subjects were asked to complete a postal questionnaire concerning past diet and lifestyle. The completed questionnaires were collected when they had health examinations. The 15 questions included their preference for sweets, how many between-meal snacks they usually had per day, smoking and drinking habits, presence of oral symptoms, and attitudes towards dental visits. Participants were asked about their behaviors at different stages of their life. The oral health examinations included examination of the oral cavity and teeth performed by dentists using WHO criteria. Odds ratios were calculated for all subjects, all 10 year age groups, and for subjects 30 years or older, 40 years or older, 50 years or older, and 60 years or older. RESULTS: Frequency of tooth brushing (OR = 3.98), having your own toothbrush (OR = 2.11), smoking (OR = 2.71) and bleeding gums (OR = 2.03) were significantly associated with number of retained teeth in males. Frequency of between-meal snacks was strongly associated with number of retained teeth in females (OR = 4.67). Having some hobbies (OR = 2.97), having a family dentist (OR = 2.34) and consulting a dentist as soon as symptoms occurred (OR = 1.74) were significantly associated with number of retained teeth in females. Factors that were significantly associated with tooth loss in both males and females included alcohol consumption (OR = 11.96, males, OR = 3.83, females), swollen gums (OR = 1.93, males, OR = 3.04, females) and toothache (OR = 3.39, males, OR = 3.52, females). CONCLUSION: Behavioral factors that were associated with tooth retention were frequency of eating snacks between meals, tooth brushing frequency, having one's own toothbrush, smoking and drinking habits, having hobbies, having a family dentist and when they had dental treatment. Clinical factors included bleeding gums, swollen gums, and toothache.

Journal Article↗
PubMed2006

Premolar and molar rotation in wild Japanese serow populations on Honshu Island, Japan.

The skulls of 1195 Japanese serow (Capricornis crispus) from six geographically distinct populations were examined for tooth rotation. Our objectives were to determine tooth rotation patterns in Japanese serows, investigate geographical variation in tooth rotation and examine whether space limitations in the jaw accounted for variations. We then sought to explain the origin of tooth rotation in the Japanese serow. Rotated teeth were found in 131 specimens (62 males, 57 females and 12 unknown gender), with no statistically significant difference between males and females (chi(2)=0.03, P=0.86, d.f.=1). Among the six populations, the frequency of tooth rotation varied from 3.7-32.1% (average 11.0%). Most tooth rotation occurred in the upper third and fourth premolars. The lingual cusp of anomalous teeth was rotated 30 degrees -90 degrees mesially or distally from the buccolingual tooth axis, and the rotation direction differed among populations. However, we found no difference in skull or tooth morphology between normal individuals and those with tooth rotation. Therefore, hereditary factors may be involved in Japanese serow tooth rotation. We concluded that genetic differentiation occurred in the past among local Japanese serow populations isolated in mountainous habitats. Gene frequencies were likely subject to random drift, especially during possible population bottlenecks, when genetic factors could most strongly affect the direction of rotation.

Animals↗
PubMed2006

The effects of fluoride on the nanostructure and surface pK of enamel crystals: an atomic force microscopy study of human and rat enamel.

Atomic force microscopy (AFM) studies have revealed 30-40 nm-wide regular positively charged bands across maturation-stage rat enamel crystals. Low pH resolved these into positively charged spherical domains of approximately 30 nm diameter. Crystal surface pK values from adhesion force titrations were approximately 6.5. The effect of fluoride on this pK value and on the nanostructure of fluorosed human enamel crystals has not been reported. The nanostructure and surface chemistry (pK) of normal and fluorotic human and of fluoride-treated rat maturing enamel crystals was examined. Enamel was sectioned and polished, prior to examination, using AFM in height and friction modes. High-resolution height images revealed 30 nm-diameter spherical domains within crystals, arranged as layers of hexagons or as a shallow spiral. Fluorotic enamel showed similar, but less well ordered, nanodomains. These could represent an arrangement of original initiation sites or binding sites for modulating matrix proteins. Surface pK was derived from adhesion-force measurements between functionalized tips (OH or COOH) and crystal surfaces between pH 2 and pH 10. pK values of approximately 6.5 for normal crystals were reduced to approximately 5.5 after fluoride treatment. Reduction in surface pK by fluoride might indicate lowered protonation with possible effects on matrix protein binding.

Amelogenesis↗
PubMed2006

Relationship between survival rates and numbers of natural teeth in an elderly Japanese population.

OBJECTIVES: The objective of this study was to assess whether elderly people with 20 or more natural teeth were more likely to live longer than a cohort with less than 20 teeth. MATERIALS AND METHODS: Groups of elderly people over 80 years of age (24 males and 35 females) with 20 or more teeth (>or=20 group) were compared with elderly people (24 males and 35 females) with less than 20 teeth (<20 group). Follow-up studies were conducted at regular intervals for 10 years from July 1992 to July 2002. The cumulative survival rate of the >or=20 group (average +/- SE tooth number of teeth - males, 23.9 +/- 0.6; females, 23.8 +/- 0.4) was compared with the <20 group (average number of teeth - males, 3.8 +/- 1.1; females, 2.6 +/- 0.8). The multivariate Cox proportional hazard models with the number of teeth in a group (>or=20 group or <20 group). Smoking status and alcohol intake as covariates were used to adjust the cumulative survival rate. RESULTS: The male participants in the >or=20 group had a significantly higher cumulative survival rates (p < 0.05) than the <20 group at 18 and 21 months from baseline. There were no significant differences in survival rates between the female groups. Adjusted cumulative survival rate was significantly different at 72, 75 and 78 months between the >or=20 group and <20 group for males but not for females. CONCLUSION: Having 20 or more natural teeth was associated with increased survival rate in elderly males, but not among the elderly females.

Age Distribution↗
PubMed2006

A model of spontaneous periodontitis in the miniature goat.

BACKGROUND: The pathogenesis and progression of periodontal disease have been extensively studied through the use of animal models. However, no animal model has yet been established that is precisely similar to periodontitis in humans. In the present study, we examined the use of Shiba goats as a model for spontaneous periodontitis. METHODS: Thirty-four Shiba goats (seven males and 27 females, aged 10 to 98 months) were used. We examined periodontitis in Shiba goats clinically, histopathologically, and microbiologically. RESULTS: The mean probing depth (PD) of the 68 teeth examined was 2.7 +/- 0.8 mm. The incidences of PD > or =3 and 4 mm were 46.4% and 22.1%, respectively. The incidence of bleeding on probing in 68 sites and in 34 animals was 60.7% and 73.5%, respectively. The formation of vertical alveolar bone defects and downgrowth of gingival epithelial cells were found in the areas of periodontitis. The prevalence of Tannerella forsythensis, Campylobacter rectus, Fusobacterium necrophorum, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans in subgingival plaque by polymerase chain reaction was 46.4%, 28.5%, 28.5%, 17.8%, and 3.5%, respectively. These percentages were increased in subgingival plaque from PD > or =3 mm. CONCLUSIONS: The clinical, histopathological, and microbiological features of spontaneous periodontitis in Shiba goats were somewhat similar to those in human periodontitis. Moreover, there are some advantages of using the Shiba goat; the size of the oral cavity is suitable for periodontal treatment, and handling and housing are relatively easy. Therefore, these results suggest that the Shiba goat is a useful animal model for human periodontitis.

Animals↗
PubMed2005

The effect of fluoridation and its discontinuation on fluoride profiles in the alveolar bone of rat.

We investigated the effect of fluoridation and its discontinuation on fluoride content in the alveolar portion of the mandible in rats. Drinking water with three different fluoride contents (0, 50, 100 ppmF) was given to rats for three different periods (4, 13 and 25 weeks). Fluoride concentrations were measured in the crest, the middle, and the apical parts of the alveolar bone and in the body of the mandible. Furthermore, after fluoridated drinking water was given to rats for 4 or 13 weeks, distilled water was given to them for 21 or 12 weeks respectively; and the effect of the discontinuation on fluoride profiles was investigated. Layer samples were analyzed by abrasive microsampling. Fluoride and phosphorus concentrations were determined by ion-specific electrode and colorimetric procedures, respectively. There was an increase in fluoride concentrations in the mandible in proportion to the fluoride content in the drinking water and the duration of fluoridation. After fluoridation was discontinued, fluoride concentrations in the surface layers of the mandible presented a decrease. Among the four different parts of the mandible, the upper part of the alveolar bone and the alveolar crest part presented the highest rates of reduction. The relative reduction rate of fluoride concentration was closely related to the duration of discontinuation. The alveolar crest was affected most by the discontinuation of fluoridation, presenting the greatest reduction.

Animals↗
PubMed2005

Variations in the number of teeth in wild Japanese serow (Naemorhedus crispus).

Skulls of 755 Japanese serow (Naemorhedus crispus) were examined for numerical anomalies of teeth, and these were found in 30 (4.0%) specimens. In addition to supernumerary and congenital missing teeth, embedded teeth were also identified. Supernumerary teeth were found in 10 (1.3%) specimens, congenital missing teeth were found in nine (1.2%) specimens, and embedded teeth were found in 11 (1.5%) specimens. Supernumerary teeth were found among the incisors, the upper and lower premolars, and the lower molars. Based on the appearance of certain tooth classes, their size, and their form, atavism was considered to be a possible cause of the occurrence of some of these teeth. Congenital missing teeth were found at the loci of the lower incisors, canines and P(2). In Japanese serow, there appeared to be a tendency for congenitally missing P(2) as well as P(1). All embedded teeth were found at the locus of P(2). These teeth may have occurred as an intermediate state between normal and congenital missing teeth. Variations in the number of teeth in Japanese serow were concordant with their phylogenetic background. Moreover, although variations in the number of cheek teeth tended to be concentrated in the mesial region of the premolars, the tendency in the incisive region was for teeth to appear mesial as well as distal within an incisor-tooth sequence. These results, which are not in accordance with terminal reduction theory, indicate that the phenomenon of tooth degeneration does not only occur at the end of a tooth row.

Animals↗
PubMed2005

["Oral healthiness score for 8020" predicts loss of teeth in village residents].

OBJECTIVE: It is important for people to maintain an appropriate lifestyle through out life to enjoy a healthy life. We have already developed a health check questionnaire, "8020 Oral Healthiness Score", in an endeavor to help people aged 80 keep more than 20 teeth. The health check consists of ten questions chosen from our previous residents' study. Named the "Sawayaka Score" it has been in use since 1999. In the present study, we focused on the results of a three-year follow-up to determine whether the Score may predict tooth loss for screening purposes. METHODS: A total of 716 village residents who participated in medical and dental checkups in 1999 as the baseline year were followed in T village of Aichi-Prefecture. The total numbers of teeth lost were examined after 1-, 2- and 3-years and odds ratios with 95% confidence intervals (CI) were generated for analysis of screening. RESULTS: At the 1999 baseline, the average number of retained teeth was 23.7 +/- 6.2 (mean +/- standard error) (23.0 +/- 6.8 in males, and 24.4 +/- 5.5 in females), and the average oral health score (mean +/- standard error) was 13.1 +/- 3.9 points (12.8 +/- 4.0 in males, 13.4 +/- 3.9 in females). A low score of 4-8 at the baseline predicted major tooth loss, while an average score was associated with loss of only one or 2 teeth loss in the residents. The present study confirms that persons with a favorable lifestyle tend to retain more teeth. CONCLUSION: It can be concluded that the 8020 Oral Healthiness Score is a useful tool to support residents' oral health promotion and predict tooth loss.

Aged↗
PubMed2005

Relationship between oral Candida species and risk factors with reference to drugs with xerostomic side effects among institutionalised elderly in Aichi Pref., Japan.

OBJECTIVE: To clarify the relationship between Candida carriage and drugs which have reported xerostomic side effects in the elderly. DESIGN: Cross-sectional study. Setting Two long-term care facilities in Aichi Pref., Japan. PARTICIPANTS: Eight men and 63 women with a mean age of 86 years (range 62 to 95 years) with at least some of their natural teeth. METHOD: Oral examination by dentists, microbiological test by microbiologists, questionnaire interviews, and data obtained from medical files. The Candida species (CFU) was adopted as an objective variable with risk indicators being age, number of teeth, saliva flow rate, denture wearing, xerostomic drugs, activities of daily living (ADL), frequency of brushing and type of meals. RESULTS: Bivariate analysis confirmed that participants with a higher number of Candida species (CFU) fell into the following categories: denture wearing (p < 0.05), older age (p < 0.05), xerostomic drugs (p < 0.10), more teeth, poor ADL, soft/liquid meals, and brushing once a day. This was in contrast to the categories of no denture wearing, younger age, no xerostomic drugs, fewer teeth, good ADL, normal meals, and brushing two or more times a day, in that order of significant probability on an ascending scale. A multiple logistics regression model confirmed that the variables of older age (80 years and over) and more teeth (six or more) had statistically significant (p < 0.05) effects on the number of Candida species present (CFU). Xerostomic drugs and the other variables had no significant effect. CONCLUSION: Older age and more teeth had a significant effect on the number of oral Candida species in the elderly. The results of this study did not support a role of those drugs as a risk indicator for oral Candida carriage. Larger trials are needed to assess the effect of drugs on the presence of oral Candida.

Age Factors↗
PubMed2004

Success rate of endodontic treatment of teeth with vital and nonvital pulps. A meta-analysis.

OBJECTIVE: The purpose of this study was to use meta-analysis statistics to determine the influence of factors such as apical limit (short vs. overextension), status of the pulp (vital vs. nonvital), and periapical status (presence or absence of radiolucency) on endodontic prognosis. Study design The study-list was obtained by using a MEDLINE search and Japana Centra Revuo Medicina search. Only those papers in which the criteria for success or failure was exactly described were accepted. RESULTS: The cumulative success rate of 82.8 +/- 1.19% (average +/-95% confidence interval) was obtained for vital pulp; and 78.9 +/- 1.05%, for nonvital ones. There was a significant difference between the 2 groups.The cumulative success rates with overextension, flush, and underextension in vital teeth were 70.8 +/- 1.44, 86.5 +/- 0.88, and 85.5 +/- 0.98% respectively. There was a significant difference between flush and overextension and between flush and underextension. The rates for nonvital pulp were similar to those for vital ones. CONCLUSION: The root canal should be filled to within 2 mm of the radiographic apex.

Adult↗
PubMed2004

Masticatory performance in 80-year-old individuals.

OBJECTIVE: To evaluate the masticatory performance of elderly people at the age of 80 years. SUBJECTS: A total of 283 individuals of 80 years of age took part in a general and dental health survey. MAIN OUTCOME MEASURES: A dental examination including the number of remaining teeth, occlusion, prostheses, bite force recording, and a questionnaire regarding masticatory performance were recorded. SETTING: Five municipalities (Okazaki city, Tokoname city, Tahara town, Atsumi town and Minami-chita town) in Aichi prefecture, Japan. RESULTS: There were 20 or more teeth in 7.4% subjects, and 44.5% were edentulous. Subjects with no occlusion accounted for 77.4% of the total. Subjects with prostheses accounted for 90.8%. Maximum bite force and masticatory ability score for patients with 20 or more teeth or not wearing prostheses were higher than other groups. The non-wearing prostheses group had a low masticatory ability score. CONCLUSION: Most of the 80-year-old individuals recovered their masticatory ability with the assistance of prostheses. Several individuals with 20 or more remaining teeth or without removable dentures present in both jaws had a high score for bite forces and masticatory abilities.

Aged↗
PubMed2003

Fluoride profiles in premolars after different durations of water fluoridation in Ho Chi Minh City, Vietnam.

In order to evaluate the uptake of fluoride (F) into tooth structures following water fluoridation in Ho Chi Minh City, F concentrations were measured from the enamel surface through the enamel-dentine junction (EDJ) to dentine close to the pulp in premolars. Calcification had been completed in all the teeth before fluoridation. Samples were obtained from fluoridated areas of the City ([F]: 0.7 parts/10(6)) after 3 years (eight samples), 6 years (eight samples) and 8 years (nine samples). Samples were also taken from regions outside the fluoridated water supply of the City in 1998 after 8 years of water fluoridation. An abrasive microsampling method was used to determine the profiles of fluoride and phosphorus concentrations. In enamel surfaces, F concentrations tended to increase with increasing periods of fluoridation. In dentine close to the pulp, F concentrations also increased statistically significantly with the increasing duration of fluoridation of water (between 6 and 3 years: P=0.006; between 8 and 3 years: P=0.001; between 8 years and 8 years without F: P=0.0001). It was concluded that F concentrations in enamel and dentine had tended to increase gradually with the duration of water fluoridation in Ho Chi Minh City. The increase was most obvious in dentine near the junction with the pulp.

Adolescent↗
PubMed2003

Oral pre-cancer and the associated risk factors among industrial workers in Japan's overseas enterprises in the UK.

BACKGROUND: Screening at industries has been advocated as a method of early detection for cancer. This study describes the prevalence of oral pre-cancerous lesions and other mucosal diseases following oral mucosal screening, and associated risk factors among Japanese industrial workers in the UK. METHODS: Oral mucosal screening was by invitation at 51 industrial locations in the UK. A self-administered questionnaire was used to record socio-behavioural factors and frequency of daily intake of fruits and vegetables. RESULTS: Four hundred and eighty-four subjects attended for oral mucosal screening (mean age 39.9 +/- 8.3 years) and their mean period of residence in UK was 5.3 +/- 4.5 years. 63.4% examined were male. 31.3% of males and 26.6% of females smoked daily. The gender differences were striking compared with Japan's national rates. A higher proportion of managerial staff was regular heavy (20+ per day) smokers. The intake of more than five portions per day of vegetables and/or fruits during the weekend was significantly higher in females than in males (P = 0.022). One hundred and six subjects (22%) were detected with oral mucosal lesions, including 16 leukoplakia lesions (3.3%) and three with oral lichen planus (1%). The rate of positive detections was higher in managers (7.5%). Odds ratios were estimated by socio-behavioural variables. Among subjects positive for oral leukoplakia, managers accounted for 68.8% (OR 5.26; 95% CI, 1.24-22.29). 87.5% of subjects detected with oral leukoplakia smoked daily and had done so for the past 10 years (OR 28.40; 95% CI, 5.63-143.28). Though regular alcohol drinking was a common feature among male leukoplakia cases, heavy alcohol misuse was not encountered. None reported an intake of five or more portions of fruits or vegetables. CONCLUSIONS: The Japanese nationals working in managerial positions in the UK and daily regular smokers in the industries visited were found to be at a high risk of oral pre-cancer. Regular dental/oral check up and tobacco education programmes are encouraged for oral cancer/pre-cancer control in industrial settings.

Adolescent↗
PubMed2003

[Effect of professional oral prophylaxis on the general health perceptions and lifestyles in workers of a worksite].

The present study was undertaken to look at the effect of professional oral prophylaxis on the general health perceptions and lifestyle in workers at a worksite in Aichi-ken. Dental check-ups and three kinds of questionnaires (SAS: The Social Adjustment Scale, MOS: The Medical Outcomes Study and the nutrition) were used in this investigation for three years from 1998. By means of the stratified sampling method, the participants were 265 workers separated into a case and a control group, who work for a pharmaceutical company (201 males, 64 females, average age 35.6 +/- 0.7 yr old). All participants gave their consent to the study. As in the case group, dental hygienists scaled their teeth and gave each of them appropriate advice about their oral health twice in a year. MOS, SAS, nutrition and oral health in the case and control groups were compared with the baseline, third and the final year. The results were as follows; 1) There was significant difference in energy, protein, fat, fish and meats sufficiency rates (p < 0.05) and a higher tendency towards consuming sugar, potassium (K), calcium (Ca), iron (Fe) and Fiber (p < 0.10) in the control group, but there were no significant differences in the other nutrients in the case and control groups. 2) There were significant differences in the number of decayed teeth in the case group, and in the number of filled teeth and decayed teeth in the control group. The gingival condition (CPI = 0) in the case group tended to be higher healthier than the control group, 3) In the MOS questionnaire, the case group was better or not worse in health perceptions scales, pain scales and mental health scales than the control group. 4) In the SAS questionnaire, the case group was better or not worse in the work and the social scales than the control group. It was concluded that oral health, social health and consciousness of health tended to improve by dental intervention.

Adult↗
PubMed2003

Blood test values and Community Periodontal Index scores in medical checkup recipients.

BACKGROUND: We examined the blood test values of people who received general medical checkups and their Community Periodontal Index (CPI) score. METHODS: A total of 7,452 persons (5,742 males and 1,710 females), who had general medical and dental checkups, were the subjects of the study. Many were people who worked for companies in and around Nagoya and their family members, ranging in age from 16 to 80 years. The blood test in our study consisted of 37 items used in general blood tests. Partial-mouth recordings were used to measure CPI scores. The highest CPI score for each subject was used for analysis. Odds ratios and confidence interval values were obtained using the Mantel-Haenszel method to analyze the results. RESULTS: CPI scores of 3 and 4 were related to the test values of high-density-lipoprotein cholesterol, serum iron, white blood cell count, fasting blood sugar, glycosylated hemoglobin A1, glycosylated hemoglobin A1c, and C-reactive protein. CONCLUSION: Blood test values tended to show correlations with CPI scores, more clearly seen in males than in females.

Adolescent↗
PubMed2003

[The relationship between normal swallowing functions, food ingestion and the lifestyle of users in a day service center].

OBJECTIVES: The physical and mental condition of elderly people changes every day and we hypothesized that this influences food intake and swallowing functions. The present study was undertaken to clarify relationships between daily living conditions and swallowing function. METHODS: The subjects were users (105 males and 219 females) of 6 day-service centers. We performed a survey of IADL (Instrumental Activities of Daily Living), mobility, eating and swallowing behavior, and general health. In addition, we used RSST (Repetitive Saliva Swallowing Test) as a screen for functional dysphasia. RESULTS: Women who had normal food ingestion and swallowing functions were capable of doing shopping, housework and taking care of money independently. Males and females who were capable of moving around from place to place had normal food ingestion and swallowing functions. With regard to daily eating habits and health condition, males and females who had normal food ingestion and swallowing functions were able to consume ordinary food, able to eat without any help, and often laugh. CONCLUSION: It was concluded that a normal swallowing condition in the elderly is related to laughing often, being independent in daily life, moving around and eating ordinary meals without any help.

Activities of Daily Living↗
PubMed2003

[Comparison of results of a dental questionnaire between from randomly sampled residents and patients of dental clinics in the same city].

OBJECTIVES: The present study was undertaken to clarify the nature of sampling results with dental questionnaires between random sampling of subjects and of patients of dental clinics in the same city. METHODS: The first group comprised 900 subjects selected using the stratified random sampling based on different age groups. The sampling rate was set at 6.46% of the population database and the approach was a mail survey with random sampling. The second group comprised 240 subjects who were patients of 12 dental clinics. The questionnaire had a list of questions about oral health conditions, daily oral habits, daily activities and common eating habits. RESULTS: The response rates with the mailing method in the first group were 41.0% for male and 49.0% for female residents. The percentages who answered "Yes" to the questions, "Do you have gum swelling?" and "Have you ever received any instructions on tooth brushing from a professional?", were significantly (P < 0.05) lower than for patients from dental clinics. CONCLUSIONS: Dental patients had poor oral health habits and more oral diseases than residents, who visited dentists less frequently. It can be concluded that patients from dental clinics are inappropriate to use as samples to set a baseline for the general population in research evaluation of oral health.

Adult↗