Ichizo Morita

Five-Year Incidence of Periodontal Disease Is Related to Body Mass Index

Numerous cross-sectional epidemiological studies suggest that obesity is associated with periodontal disease. This longitudinal study tested whether body mass index (BMI) was related to the development of periodontal disease in a sample of employed Japanese participants. Data are from the statutory medical checkups routinely collected for employees in and around Nagoya, Japan. The authors tested the relationship between BMI at baseline and the 5-year incidence of periodontal disease in a sample of 2787 males and 803 females. The hazard ratios for developing periodontal disease after 5 years were 1.30 (P < .001) and 1.44 (P = .072) in men and 1.70 (P < .01) and 3.24 (P < .05) in women for those with BMIs of 25-30 and ≥ 30, respectively, compared to those with BMI < 22, after adjusting for age, smoking status, and clinical history of diabetes mellitus. These findings demonstrate a dose-response relationship between BMI and the development of periodontal disease in a population of Japanese individuals.

Relationship between Periodontal Status and Levels of Glycated Hemoglobin

The objective of this study was to assess whether there is a bi-directional relationship between periodontal status and diabetes. Study 1 included 5,856 people without periodontal pockets of ≥ 4 mm at baseline. Relative risk was estimated for the 5-year incidence of periodontal pockets of ≥ 4 mm (CPI scores 3 and 4, with the CPI probe), in individuals with glycated hemoglobin (HbA1c) levels of ≥ 6.5% at baseline. Study 2 included 6,125 people with HbA1c < 6.5% at baseline. The relative risk was assessed for elevation of HbA1c levels in 5 years, with baseline periodontal status, assessed by CPI. Relative risk of developing a periodontal pocket was 1.17 (p = 0.038) times greater in those with HbA1c of ≥ 6.5% at baseline, adjusted for body mass index (BMI), smoking status, sex, and age. Relative risks for having HbA1c ≥ 6.5% at 5-year follow-up in groups with periodontal pockets of 4 to 5 mm and ≥ 6 mm at baseline were 2.47 (p = 0.122) and 3.45 (p = 0.037), respectively, adjusted for BMI, alcohol consumption, smoking status, sex, and age. The risk of developing periodontal disease was associated with levels of HbA1c, and the risk of elevations of HbA1c was associated with developing periodontal pockets of more than 4 mm.

Temporal Association of Elevated C-Reactive Protein and Periodontal Disease in Men

BACKGROUND Most studies on the relationship between serum C-reactive protein (CRP) and periodontal disease have been cross-sectional. In this study, we investigated the temporal association between CRP and periodontal disease by following a large number of subjects for 1 year. METHODS We studied 11,162 men in Nagoya, Japan, who had an initial dental examination as part of a complete physical examination and then underwent the same examination 1 year later. For the 4,997 men without periodontal disease at baseline, logistic regression analysis was performed to examine the relationship between baseline CRP and periodontal disease 1 year later, adjusting for age, body mass index, glycosylated hemoglobin A1c level, and smoking status. Similarly, logistic regression analysis was performed to examine the relationship between periodontal disease at baseline and CRP 1 year later for the 10,376 men with normal baseline CRP, adjusting for the same confounding factors. RESULTS Among men without high CRP at baseline, periodontal disease at baseline correlated to CRP 1 year later. The odds ratio was 1.336 (95% confidence interval [CI]: 1.115 to 1.674). However, in the men without periodontal disease, no significant correlations were seen with baseline CRP or periodontal disease 1 year later. The odds ratio was 1.163 (95% CI: 0.894 to 1.513). CONCLUSION Periodontal disease increased the risk for high serum CRP levels in men after 1 year of follow-up.

Daily use of dentifrice with and without xylitol and fluoride: effect on glucose retention in humans in vivo

The effect of daily use of three different dentifrices on glucose retention after glucose mouth rinsing was tested in this study regarding xylitol and fluoride. Six experimental groups used three different dentifrices produced by two different companies: xylitol- and fluoride-containing dentifrice (XF), non-xylitol- and fluoride-containing dentifrice (F), and non-xylitol- and non-fluoride-containing dentifrice (NonX-NonF). Subjects were divided at random and rinsed their mouths for 15s with 20ml of 0.5M glucose solution. Glucose and lactate retention were determined by collecting samples of saliva from the approximal areas of the maxillary and mandibular anterior teeth and using the enzyme membrane test. Samples were collected 0, 1 and 2 months after the start of regular dentifrice use. There were significant differences in glucose retention in relation to the dentifrice used, month of sampling, site of sampling, and time since start of rinsing. Their contribution ratios were 2.0, 4.4, 11.7 and 7.4%, respectively (P<0.01). There were significant differences observed between the XF and NonX-NonF groups, with the XF group presenting lower glucose retention than the NonX-NonF group. The XF group presented lower glucose retention than the F group. The F group showed lower glucose retention than the NonX-NonF group. There were significant differences in lactate retention in relation to the month and site of sampling, and their contribution ratios were 3.3 and 2.8%, respectively (P<0.01). There were, however, no significant differences in glucose and lactate retention in relation to the dentifrice manufacturer. It was concluded that the XF dentifrice was the most effective, and the F dentifrice was more effective in reducing glucose retention than the NonX-NonF dentifrice.

Relationships between mandibular cortical bone measures and biochemical markers of bone turnover in elderly Japanese men and women

OBJECTIVE The aim was to clarify the association between dental panoramic radiography measures of mandibular inferior cortical shape and biochemical markers of bone turnover in elderly men and women. STUDY DESIGN Subjects were 80-year-old men (n = 85) and women (n = 153). Mandibular cortical shape and width were evaluated on dental panoramic radiographs. Bone formation and resorption, respectively, were estimated by serum levels of carboxy-terminal propeptide of type I collagen (PICP) and serum type I collagen carboxy-terminal telopeptide (ICTP). RESULTS Eroded cortices of the mandible were significantly associated with increased serum PICP levels (P = .005) in women. Lower mandibular cortical width quartiles were also significantly associated with increased serum PICP levels in men (P = .020) and women (P = .006). CONCLUSIONS Mandibular inferior cortical measures detected on dental panoramic radiographs may be associated with bone formation rates and be useful in predicting osteoporosis in elderly Japanese men and women.

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.

Glucose retention on the surfaces of primary teeth in 3- and 4-yr-old children

Glucose retention was determined in 38 kindergarten children ages 3-4 yr. The children rinsed their mouths with 10 ml of a 0.5 mol/l glucose solution for 15 s and then spat out. Three minutes after they put the solution in their mouths, a small paper-point was used to collect samples of saliva from the labial and buccal surfaces of the maxillary and mandibular primary teeth. The concentration of glucose in the small amount of saliva collected was measured with an immobilized enzyme system. Glucose retention was highest on the maxillary central primary incisor, second highest on the maxillary first primary molar and third highest on the maxillary lateral primary incisor. An intermediate value was seen on the maxillary and mandibular second primary molars, the mandibular first primary molar and the maxillary primary canine. A lower value was observed on the mandibular primary canine and the lowest on the mandibular incisors. It was concluded that there were site differences in glucose retention on primary teeth of 3- and 4-yr-old children.

Fluoride profiles in different sites of approximal surfaces of second primary molars after topical application of acidulated phosphate fluoride gel in vivo

Thirty-four (17 paired) extracted second primary molars were obtained from 17 individuals (9 boys and 8 girls) aged from 9 yr 2 months to 12 yr 7 months. A tooth on one side was extracted as a control, and an acidulated phosphate fluoride (APF) gel was then applied to the paired contralateral second primary molar. Three months later, the experimental tooth was extracted. Nine sites were assayed by a microsampling technique from small areas of the approximal enamel surface. The fluoride and phosphorus concentrations were determined by a fluoride electrode and by colorimetric procedure, respectively. Fluoride concentrations were higher in the teeth treated with the APF gel than in the control teeth. The highest fluoride uptake was observed in the central area of the approximal surfaces. Deeper areas (> 10 microns) had a marked uptake of fluoride as compared with surface areas (< 3 microns). It was concluded that the APF gel application increased the fluoride levels of approximal tooth surfaces, particularly the mid-central site, of second primary molars, even at 3 months after application.

Effect of stopping fluoride administration on the distribution profiles of fluoride in three different kinds of rat bones

The aim of this work was to explore the reduction of fluoride concentrations in the skeleton after stopping experimental fluoride administration. Fluoride was administered to the rats at varying doses (0, 50, 100 ppm in drinking water) and for different lengths of time (4, 13, 25 weeks). A series of fluoride concentrations across the full thickness of humerus, parietal bone, and vertebra arch in rats were measured by means of an abrasive micro-sampling technique. The distribution profiles of fluoride from periosteal to endosteal surfaces, which were apparently related to the histological structure of these bones, were U shaped in the humerus, V shaped in the parietal bone, and W shaped in the vertebra arch. The average fluoride concentrations in the bones increased significantly with each increasing dose and length of fluoride administration. The relative increments were similar between the different regions or the different bones. After stopping fluoride administration, on the other hand, the relative reduction of the average fluoride concentrations in the bones were 30–100%. They were greatly related to the length after stopping fluoride administration and the dose and length of fluoride administration, but also dependent upon the type of bone and the region examined.

Impact of interocclusal contacts on infrared laser fluorescence in pits of sound first permanent molars in children.

BACKGROUND A device based on infrared laser fluorescence (IRLF) has become available as an adjunct for the diagnosis of dental caries. AIMS The objective of this study was to clarify the differences of IRLF readings in the mesial, central and distal occlusal pits of first permanent molars. DESIGN Sixty-four children (average age 8.0 years) were examined using IRLF. The mesial, central and distal pits of clinically healthy first permanent molars were measured. The instrument provides measurements in arbitrary units on an open-ended interval scale. RESULTS Mean (± SE) IRLF values in the mesial pits were 4.9 ± 0.4 (upper) and 6.5 ± 0.4 (lower) and were significantly lower than those in the central (8.8 ± 0.6 and 11.5 ± 0.9) and distal (9.6 ± 0.7 and 10.4 ± 0.8) pits in the maxilla and mandible. There was no significant difference between the right (7.3 ± 0.5, 9.4 ± 0.6) and left (8.2 ± 0.5, 9.5 ± 0.6) dental arches. IRLF measurements in the mesial pits of human first permanent sound molars were lower than the central and distal pits in children whose second molars had not erupted. CONCLUSIONS The inherently higher IRLF values of some sites should not be misinterpreted and trigger early invasive treatment.