Comparison of the effects of ultrasound toothbrushes with different frequencies on oral hygiene: A randomized-controlled clinical trial

BACKGROUND

The purpose of this study was to examine whether high-frequency ultrasound toothbrushes have different effects on oral hygiene.

METHODS

Fifty first-year dental hygiene students were randomly divided into three groups using ultrasound toothbrushes with different frequencies (1.6, 3.2 and 4.8 MHz) twice a day (3-min sessions) for 8 weeks. Plaque index (PlI) and gingival index (GI) scores were assessed at 4 and 8 weeks.

RESULTS

Changes in GI scores from baseline to 8 weeks tended to differ among the groups (p = 0.0862). The GI was significantly lower in the 3.2 and 4.8 MHz groups at 8 weeks (3.2 MHz group: p < 0.01, 4.8 MHz group: p < 0.05). At 4 weeks, the GI was significantly lower in the 3.2 MHz group (p < 0.05) and tended to be lower in the 4.8 MHz group (p = 0.07). The PlI was significantly lower in the 3.2 MHz group at 8 weeks (p < 0.01) and tended to be lower in the 1.6 and 4.8 MHz groups (1.6 MHz: p = 0.07, 4.8 MHz: p = 0.05). In addition, the PlI was significantly lower in the 4.8 MHz group at 4 weeks (p < 0.05). No significant differences in the changes in any measurements were observed among the groups.

CONCLUSIONS

The results of this study indicated that ultrasound toothbrushes with different frequencies probably have different effects on oral hygiene. However, it is difficult to conclude strongly that higher frequency ultrasound toothbrushes are more effective as there were some limitations.

Effects of Chewing Gum Base on Oral Hygiene and Mental Health: A Pilot Study

The purpose of the present study was to clarify the long-term effects of frequent chewing of unflavored and odorless gum (hereafter, gum base) on oral hygiene and mental health. This single-arm study, which started with a 4-week control and ended with a 4-week intervention period, was conducted in two phases: one in 2017 and one in 2018. The participants comprised 36 dental hygiene students (17 in 2017, 19 in 2018). During the intervention period, all participants were required to chew a piece of gum base 7 times a day for 10 min each time. The unstimulated salivary flow rate and masticatory efficiency were measured and chewing number counted. Two questionnaires －the Profile of Mood States, second edition (POMS2) and the 30-item General Health Questionnaire (GHQ-30)－ were administered to assess mental health. In both phases, the unstimulated salivary flow rate showed a significant increase after the intervention period (p<0.05). In 2017, the GHQ-30 scores and masticatory efficiency showed a tendency toward a negative correlation after the intervention period (r=－0.4647, p=0.06). In 2018, a significant negative correlation was observed between chewing number and the POMS2 scores after the intervention period (r=－0.6296, p<0.01). These findings suggest that frequent chewing of gum base increases unstimulated salivary flow rate. However, no significant change was observed in the mental health.

Relationship between General Health, Lifestyle, Oral Health, and Periodontal Disease in Adults: A Large Cross-sectional Study in Japan

The aim of this study was to investigate how general health, oral conditions, and lifestyle were associated with periodontal disease in adults, as clarifying this relationship may be useful in preventing periodontal disease. Medical checkups were conducted on individuals aged 40, 50, or 60 years. Data were obtained for analysis on a total of 36,110 patients (men, 12,784; women, 22,896). A stepwise logistic regression model was used to calculate the odds ratio (OR) for patients who were ≥code 3 according to the Community Periodontal Index (CPI). Approximately 40, 60, and 70% of men aged 40, 50, and 60 years, respectively, had a CPI score of ≥3. There were 10% fewer women than men at each age. Stepwise logistic regression revealed a BMI score of ≥30 kg/m²(OR, 1.44; 95% confidence interval [95%CI], 1.20-1.73); systolic blood pressure of ≥140 mmHg (OR, 1.09; 95%CI, 1.02-1.18); a fasting blood sugar level of ≥110 mg/dl (OR, 1.17; 95%CI, 1.04-1.30); high-density lipoprotein cholesterol level of <40 mg/dl (OR, 1.21; 95%CI, 1.06-1.37); smoker (OR, 1.59; 95%CI, 1.48-1.71); drinking ≥3 cups of Japanese sake per day (OR, 1.09; 95%CI, 1.05-1.14); use of salts for seasoning (OR, 1.17; 95%CI, 1.07-1.28); and fair and poor oral hygiene (OR, 2.27; 95%CI, 2.08-2.47) as significant risk factors for a CPI score of ≥3. These results suggest that smoking, oral hygiene status, and factors associated with metabolic syndrome are associated with periodontitis. This indicates that health guidance on tooth brushing, the importance of quitting smoking, and control of obesity may be effective in preventing the development of periodontal disease in adults.

Metabolic Syndrome, Lifestyle, and Dental Caries in Japanese School Children

The number of children with Metabolic Syndrome (MetS) has recently been increasing in Japan. Few studies have investigated the relationship between MetS and oral health. The aim of this study was to investigate the association between MetS, lifestyle, and oral health status in school children. Our goal is to utilize these results in health education aimed at preventing the onset of MetS in school children and adults. A total of 689 Japanese children (365 boys and 324 girls) aged between 10 and 13 years were examined and waist circumference (WC), ratio of WC to height, blood pressure, fasting blood sugar (FBS), high density lipoprotein-cholesterol, and triglyceride values determined together with oral health status, including dental caries experience (DMFT). The results revealed that 6.5% of the children fell under the health board recognized "MetS or high risk of MetS" (MetS/HR) classification. A total of 140 (20%) children had a high Streptococcus mutans count. The mean WC, FBS, and DMFT values were significantly greater in children with a high salivary S. mutans count (p<0.05). Multiple logistic regression analysis revealed a statistically significance association between MetS/HR, non-breakfast eaters (odds ratio (OR): 2.70), no regular exercise (OR: 2.60), and a high salivary S. mutans count (≥10(5) CFU/ml; OR: 2.18; p<0.05). The present results indicate that lifestyle and salivary S. mutans count could be useful in screening children for MetS/HR. These variables may be useful in targeting interventions aimed at preventing MetS in school children.

Loss of teeth in positions mesially adjacent to implant-supported fixed dentures: a retrospective clinical survey

The aim of this study was to investigate the loss of teeth in positions mesially adjacent to implant-supported fixed dentures (IFDs) after insertion of IFDs in unilateral free-end edentulous spaces in the mandible at dental clinics. There were a total of 157 adjacent teeth. Nine adjacent teeth (5.73%, 9 of 157), 9 opposing teeth (2.59%, 9 of 348), 38 posterior teeth (1.93%, 38 of 1,964), and 3 anterior teeth (0.22%, 3 of 1,380) were lost during the observation period. The percentage of lost adjacent teeth was higher than that of posterior teeth (P = .002). Teeth in positions adjacent to the IFDs require more attention than other remaining teeth.

Grinding efficiency of abutment tooth with both dentin and core composite resin on axial plane

The purpose of this study was to evaluate grinding efficiency in abutment teeth comprising both dentin and core composite resin in the axial plane. Grinding was performed over 5 runs at two loads (0.5 or 0.25 N) and two feed rates (1 or 2 mm/sec). The grinding surface was observed with a 3-D laser microscope. Tomographic images of the grinding surfaces captured perpendicular to the feed direction were also analyzed. Using a non-ground surface as a reference, areas comprising only dentin, both dentin and core composite resin, or only core composite resin were analyzed to determine the angle of the grinding surface. Composite resins were subjected to the Vickers hardness test and scanning electron microscopy. Data were statistically analyzed using a one-way analysis of variance and multiple comparison tests. Multiple regression analysis was performed for load, feed rate, and Vickers hardness of the build-up material depending on number of runs. When grinding was performed at a constant load and feed rate, a greater grinding angle was observed in areas comprising both dentin and composite resin or only composite resin than in areas consisting of dentin alone. A correlation was found between machinability and load or feed rate in areas comprising both dentin and composite resin or composite resin alone, with a particularly high correlation being observed between machinability and load. These results suggest that great caution should be exercised in a clinical setting when the boundary between the dentin and composite resin is to be ground, as the angle of the grinding surface changes when the rotating diamond point begins grinding the composite resin.

Fundic gland polyps accurately predict a low risk of future gastric carcinogenesis

OBJECTIVES

Few reports have analyzed the clinical importance of sporadic fundic gland polyps (FGPs). The aim of this study was to investigate the relationship between sporadic FGPs and condition of the gastric mucosa stratified by serum pepsinogen levels and Helicobacter pylori antibody level.

METHODS

Three hundred and seventy-five subjects undergoing gastrointestinal endoscopy were enrolled. Subjects on proton pump inhibitors were excluded. Pathologically proven FGPs, and other endoscopic findings (reflux esophagitis, gastric and duodenal ulcer) were examined and serum pepsinogen levels, H. pylori antibody concentration and gastric juice pH were measured simultaneously. Subjects with normal serum pepsinogen and negative H. pylori antibodies were defined as having "low risk" stomachs, suggesting low risk of gastric carcinogenesis.

RESULTS

Of the 375 subjects, 44 showed FGPs. The prevalence of "low risk" stomach in subjects with and without FGPs was 98% and 48%, respectively. Multivariable logistic regression analysis indicated three variables as independent factors positively associated with "low risk" stomachs: FGPs (odds ratio [OR] 38.6), reflux esophagitis (OR 4.8), and age<60 years (OR 1.89). Gastric juice pH, which is associated with mucosal atrophy grade and low pH indicates less mucosal atrophy, was significantly lower in subjects with (1.64 ± 0.64) than without FGPs in "low risk" (1.94 ± 1.12) and "high risk" stomachs (3.99 ± 2.31).

CONCLUSIONS

Sporadic FGPs tend to be related to the least atrophic mucosa among non-gastric atrophy subjects without H. pylori infection, and can be used as predictors of a low risk of gastric carcinogenesis.

Loss of teeth opposing implant-supported prostheses in the posterior mandible: a retrospective survey in dental clinics

PURPOSE

The main aim of this study was to investigate the loss of maxillary teeth opposing mandibular implant-supported prostheses (ISPs) placed at dental clinics.

MATERIALS AND METHODS

Participating dentists were asked to provide information on implant procedures they had undertaken between January 1, 1990, and December 31, 2009. Data were requested for procedures in which implants were inserted into only one side of the mandible in posterior regions and no implants were inserted in other regions.

RESULTS

Data on a total of 383 patients were analyzed. Participants in this study consisted of 170 men and 213 women ranging from 20 to 78 years of age (mean age, 51.0 years). Natural teeth were divided into three groups: opposing teeth (teeth opposing ISPs), control teeth (teeth of the same type as the opposing teeth but on the other side of the maxilla), and other teeth. The mean observation period was 72 months. One hundred six teeth were lost during the observation period. Fourteen opposing teeth were lost (1.72%, 14/816), 15 control teeth were lost (1.84%, 15/816), and 77 other teeth were lost (0.98%, 77/7,891). The percentage of opposing teeth lost was significantly higher than that of other teeth. However, there was no difference in the rates of loss of opposing and control teeth.

CONCLUSION

ISPs in posterior mandibular regions are not a risk factor for the loss of opposing teeth.

Survival rate in autotransplanted premolars with complete root formation: a retrospective clinical survey

The purpose of this study was to analyze the survival rate in autotransplanted premolars with complete root formation in dental clinics. Participating dentists were requested to provide information on transplantations they had undertaken between 1 January 1990 and 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. Data for other tooth types and for teeth with incomplete root formation were eliminated. In this study, data on 40 teeth in 35 patients were analyzed. Participants consisted of 17 men and 18 women ranging from 24 to 79 years in age (mean age, 43.7 years). The cumulative survival rate was 100% at the 5-year mark and 72.7% at 10 years, as calculated by the Kaplan-Meier method. Single-factor analysis revealed that "transplanted to the molar regions" was a significant risk factor (p<0.05) influencing the survival of transplanted teeth. However, a Cox regression analysis showed no significance. The results of this study suggest that, in cases where there is a suitable donor tooth and the oral condition is good, premolar autotransplantation is a viable treatment option, even when there is complete root formation in the donor teeth.

DNA methylation of the BMAL1 promoter

We previously analyzed transcriptional regulation of the BMAL1 gene, a critical component of the mammalian clock system and found that the BMAL1 gene is expressed with circadian oscillation and that its regulatory region is located in hypomethylated CpG islands with an open chromatin structure. Here, we found that the BMAL1 gene is not expressed with circadian oscillation in CPT-K cells because the CpG islands located in the BMAL1 promoter are hypermethylated and that 5-aza-2'-deoxycytidine (aza-dC) recovered BMAL1 expression. In contrast, CpG islands in the PER2 promoter were hypomethylated, the PER2 gene was expressed and aza-dC enhanced PER2 gene expression in CPT-K cells. Reporter gene assays showed that intracellular transcriptional machinery for the BMAL1 gene is active, suggesting that BMAL1 inactivation is caused by DNA methylation and not by malfunctional promoter activity. Incubating CPT-K cells with aza-dC also increased CRY1 expression, whereas CLOCK expression was not altered and the CRY1 promoter was unmethylated. These results suggest that aza-dC induces BMAL1 expression via DNA demethylation in the BMAL1 promoter and enhances PER2 and CRY1 transcription. Finally, aza-dC recovered the circadian oscillation of BMAL1 transcription. These results suggest that DNA methylation of the BMAL1 gene is critical for interfering with circadian rhythms.

Procedures for treating spaces vacated by loss of transplanted teeth

The main reasons for loss of autotransplanted teeth are different from those involved in natural teeth loss. The aim of this study was to investigate which procedures were employed to treat spaces vacated when autotransplanted teeth were lost. Participating dentists were requested to provide information on transplantations they had undertaken. A total of 614 teeth in 552 patients (37 dentists) ranging in age from 17 to 79 years (mean age: 44.1 years) were examined. A total of 102 transplanted teeth were lost during the observation period. Procedures for treatment of spaces vacated were not influenced by main reason for transplanted tooth loss. The procedure used to treat depended on the original prosthodontic treatment of the transplanted teeth. For single crowns, the spaces were left empty (33.9%) or replaced by bridge work (30.5%), implants (20.3%), or dentures (10.2%). For single crowns in the upper and lower second molar regions, the spaces were usually left empty (upper 100%, lower 71.4%), while for those in the upper and lower first molar regions, the spaces were often replaced by bridge work (upper 41.7%, lower 50.0%). For bridge abutments, spaces were replaced by dentures (42.9%), implants (33.3%), or left empty (14.3%), and in the lower second molar region, they were mostly replaced by implants (5 cases, 41.7%). For most denture abutment cases, the spaces were replaced by dentures (88.9%). During the survival period of the transplanted teeth, the masticatory burden on the other teeth is reduced and the adjacent teeth are supported by the transplanted tooth. Even if transplanted teeth are eventually lost, traditional procedures can be performed to fill the vacated space.

Gender difference in tooth autotransplantation with complete root formation: a retrospective survey

Gender-related risk factors in the survival of transplanted teeth with complete root formation have not yet been identified. The purpose of this study was to investigate gender differences in tooth autotransplantation at dental clinics. We asked participating dentists to provide information on transplantations they had undertaken from 1 January 1990 to 1931 December 2010. The data were screened to exclude patients who underwent more than one transplantation, smokers or those whose smoking habits were unknown, patients under 30 or who were 70 years old and over, cases where the transplanted teeth had incomplete root formation or multiple roots and those with fewer than 20 present teeth post-operation. We analysed 73 teeth of 73 males (mean age, 47.2 years) and 106 teeth of 106 females (mean age, 45.3 years) in this study. The cumulative survival rate and mean survival time were calculated using the Kaplan-Meier method. The cumulative survival rate for males was 88.3% at the 5-year mark, 64.8% at 10 years and 48.6% at 15 years; for females, it was 97.2% at the 5-year mark, 85.9% at 10 years and 85.9% at 15 years. A log-rank test indicated the difference between males and females to be significant (P = 0.011). There was also a significant difference in the main causes for the loss of transplanted teeth: males lost more transplanted teeth due to attachment loss than females (P < 0.05). These results indicate that males require more attention during the autotransplantation process, particularly at the stage of pre-operation evaluation and that of follow-up maintenance.

Risk factors affecting third molar autotransplantation in males: a retrospective survey in dental clinics

The aim of this study was to investigate the risk factors affecting long-term prognosis of autotransplantation of third molars with complete root formation in males at dental clinics. Participating dentists were requested to provide information on transplantations they had undertaken from 1 January 1990 to 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. After data screening and elimination, participants of this study consisted of 183 teeth of 171 males ranging from 20 to 72 years of age (mean age, 44·8 years). The cumulative survival rate was 86·0% at the 5-year mark, 59·1% at 10 years and 28·0% at 15 years. The mean survival time was 134·5 months, as calculated by the Kaplan-Meier method. Single factor analysis using the log-rank test showed that the following factors had significant influence (P < 0·05) on survival of transplanted teeth: periodontal disease as the reason for recipient site tooth extraction, fewer than 25 present teeth and Eichner index Groups B1 to C. Cox regression analysis examined five factors: age, smoking habit, recipient site extraction caused by periodontal disease, fewer than 25 present teeth and Eichner index. This analysis showed that two of these factors were significant: fewer than 25 present teeth was 2·63 (95% CI, 1·03-6·69) and recipient site extraction caused by periodontal disease was 3·80 (95% CI, 1·61-9·01). The results of this study suggest that long-term survival of transplanted teeth in males is influenced not only by oral bacterium but also by occlusal status.

Number of occlusal units estimated from number of present teeth

The aim of this study was to determine the relationship between number of present teeth (PT) and number of occlusal units (OUs). The data were obtained from a periodontal disease examination based on the health promotion law in Tokyo, Japan in 2005. Data from a total of 1,549 (524 male and 1,025 female) 60-year-old people were analyzed in this study. The number of OUs was counted by analyzing their dental charts. Any pair of opposing teeth of the same type was counted as one OU. The maximum number of OUs in a 28-tooth dentition was therefore 14. Our study revealed that the mean number of OUs decreased along with the number of PT. The OUs of the molars were lost first, followed by those of the premolars. The anterior OUs were last to be lost. The mean number of OUs was always lower than half the number of PT: 10.4 at 24 PT, 7.2 at 20 PT, 4.4 at 16 PT, and 1.3 at 10 PT. In the posterior region (premolars and molars), the mean number of OUs was 4.7 at 24 PT, 2.6 at 20 PT, and 1.0 at 16 PT. For molars, there were 1.4 OUs at 24 PT, 0.6 at 20 PT, and 0.4 at 16 PT. Participants with fewer than 20 PT had fewer than two OUs in the posterior region. This research demonstrates that the number of OUs can be estimated from the number of PT. This knowledge can be used to reveal more detailed information about the oral health status of a given population.

Serum nitrate/nitrite concentration correlates with gastric juice nitrate/nitrite: a possible marker for mutagenesis of the proximal stomach

BACKGROUND/AIMS

In the normal acid-secreting stomach, luminally generated nitric oxide, which contributes to carcinogenesis in the proximal stomach, is associated with the concentration of nitrate plus nitrite (nitrate/nitrite) in gastric juice. We investigated whether the serum nitrate/nitrite concentration is associated with that of gastric juice and whether it can be used as a serum marker.

METHODS

Serum and gastric juice nitrate/nitrite concentration, Helicobacter pylori antibody, and gastric pH were measured in 176 patients undergoing upper endoscopy.

RESULTS

Multiple regression analysis revealed that serum nitrate/nitrite concentration was the best independent predictor of gastric juice nitrate/nitrite concentration. On single regression analysis, serum and gastric juice nitrate/nitrite concentration were significantly correlated, according to the following equation: gastric juice nitrate/nitrite concentration (μmol/l) = 3.93 - 0.54 × serum nitrate/nitrite concentration (μmol/l; correlation coefficient = 0.429, p < 0.001). In analyses confined to subjects with gastric pH less than 2.0, and in those with serum markers suggesting normal acid secretion (pepsinogen-I >30 ng/ml and negative H. pylori antibody), the serum nitrate/nitrite concentration was an independent predictor of the gastric juice nitrate/nitrite concentration (p < 0.001).

CONCLUSION

Measuring the serum nitrate/nitrite concentration has potential in estimating the gastric juice nitrate/nitrite concentration. The serum nitrate/nitrite concentration could be useful as a marker for mutagenesis in the proximal stomach.

Fasting gastric pH of Japanese subjects stratified by IgG concentration against Helicobacter pylori and pepsinogen status

BACKGROUND

The clinical significance of Helicobacter pylori antibody titer has been controversial, and the association between the extent of gastric atrophy or acid secretion and H. pylori antibody concentration has not been elucidated.

MATERIALS AND METHODS

Serum pepsinogen, H. pylori antibody concentration, and fasting gastric pH (as an indicator of acid secretion) were measured in 231 patients undergoing upper gastrointestinal endoscopy. "Atrophic" pepsinogen was defined as pepsinogen-I < 70 ng/mL and pepsinogen-I/II ratio < 3. Other levels of pepsinogen were defined as "normal". Fasting gastric pH was analyzed in subjects stratified by pepsinogen level and by H. pylori antibody concentration.

RESULTS

Helicobacter pylori antibody concentration showed no significant relationship with fasting gastric pH when all subjects were analyzed together. In H. pylori-seronegative subjects, fasting gastric pH was within the normal range, irrespective of the extent of mucosal atrophy. In H. pylori-seropositive subjects, H. pylori antibody concentration was positively correlated with fasting gastric pH in subjects with "normal" pepsinogen, but inversely correlated in those with "atrophic" pepsinogen. Particularly in subjects with low H. pylori antibody concentration and atrophic mucosa, a group reportedly at high risk of noncardia cancer, the most impaired acid secretion was shown among subjects with atrophic mucosa.

CONCLUSIONS

  The relationship between acid secretion and H. pylori antibody concentration differs depending on the presence of mucosal atrophy. Our findings provide a possible rationalization for measuring both serum pepsinogen levels and H. pylori antibody concentration in gastric cancer screening.

New device for collecting intra-oral findings of unknown body

In dental identification, the collection of intra-oral images is extremely important. We propose the Dental Watch(®) as a new device for collecting intra-oral findings in situations where sufficient jaw-opening or adequate lighting cannot be obtained in such cases of dead bodies within a day after death or burned bodies encountered in mass disaster. This device is an improved home video camera for taking intra-oral images. It is lightweight and cordless, allowing it to be operated with one hand, and an audio function allows comments to be made and recorded on obtaining findings at the same time as images are taken. In addition, this device allows images of the entire oral cavity to be taken comparatively easily, even when only a minimal degree of jaw movement is available. This device is extremely useful in situations where a single dentist inspector must obtain findings and make an accurate and detailed Dental Chart.

Dental erosion and sulfuric ion exposure levels in individuals working with sulfuric acid in lead storage battery manufacturing plant measured with mouth-rinse index

To investigate dental erosion in employees working with sulfuric acid at a lead storage battery manufacturing plant and level of personal exposure to sulfuric ions, we measured sulfuric ion concentrations in the mouth rinse of those employees. We also measured exposure levels from air samples obtained from 2 employees from the same plant who did not work with sulfuric acid using a portable air sampler. At the same time, we collected and compared their mouth rinses with those from other employees. More specifically, we measured and compared sulfuric ion, calcium, and magnesium concentrations, along with pH levels from the mouth rinse of these two groups. Positive correlations were found between sulfuric ion and calcium concentrations (r=0.61, p<0.005), calcium and magnesium concentrations (r=0.61, p<0.005), Ca/Mg and calcium concentrations (r=0.64, p<0.005), and sulfuric ion and magnesium concentrations (r=0.55, p<0.005). Negative correlations were found between sulfuric ion concentrations and pH levels (r=-0.31, p<0.01), and magnesium concentrations and pH levels (r=-0.32, p<0.01). This suggests that mouth rinse from employees working with sulfuric acid could function as an indicator of sulfuric ion concentration in the work environment. Furthermore, this could lead to the development of a more accurate indicator of individual exposure.

Prediction of fasting gastric pH using serum biological markers

BACKGROUND/AIMS

Previous studies have suggested that hypochlorhydria has the potential to produce adverse effects such as the development of infections of the intestinal or respiratory tract and impaired drug absorption. This indicates the importance of obtaining a noninvasive method by which this condition may be diagnosed. The purpose of this study was to determine whether fasting gastric pH could be predicted noninvasively using serum biological markers.

METHODOLOGY

One hundred thirty-two patients undergoing diagnostic upper gastrointestinal endoscopy were recruited. Serum levels of pepsinogen-I, pepsinogen-II and Helicobacter pylori antibody were analyzed and the pH of fasting gastric juice determined. Multiple linear regression analysis was used to determine the best predictors of fasting gastric pH.

RESULTS

Pepsinogen-I and the presence of Helicobacter pylori were independent predictors of fasting gastric pH, and a high coefficient of determination was obtained (R2 = 0.503, root mean square error = 1.45). The equation for this model was as follows: fasting gastric pH = 2.97-0.026 (pepsinogen-I)+2.76 (presence of Helicobacter pylori: 0=absent, 1=present).

CONCLUSIONS

The model equation offers a noninvasive method by which to identify patients at high-risk of developing complications induced by hypochlorhydria.

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.

Saliva-Promoted Adhesion of Streptococcus mutans MT8148 Associates with Dental Plaque and Caries Experience

Colonization of enamel surfaces by Streptococcus mutans is thought to be initiated by the attachment of bacteria to a saliva-derived conditioning film (acquired pellicle). However, the clinical relevance of the contribution of saliva-promoted S. mutans adhesion in biofilm formation has not yet been fully elucidated. The aim of this study was to correlate saliva-promoted S. mutans adhesion with biofilm formation in humans. We correlated all measurements of salivary factors and dental plaque formation in 70 healthy subjects. Dental plaque development after thorough professional teeth cleaning correlated positively with S. mutans adhesion onto saliva-coated hydroxyapatite pellets and the glycoprotein content of either parotid or whole saliva. Saliva-promoted S. mutans adhesion and glycoprotein content were also positively correlated with each other in parotid and whole saliva. By contrast, neither salivary mutans streptococci, Lactobacillus nor Candida correlated with biofilm formation. Parotid saliva-mediated S. mutans adhesion was significantly higher in 12 caries-experienced (CE) subjects than in 9 caries-inexperienced (CI) subjects. Salivary S. mutans adhesion was significantly less (p < 0.01) in the CI group than in the CE group. In conclusion, the present findings suggest the initial S. mutans adhesion, modulated by salivary protein adsorption onto the enamel surface, as a possible correlate of susceptibility to dental plaque and caries.

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.

Statherin and Histatin 1 Reduce Parotid Saliva-Promoted Streptococcus mutans Strain MT8148 Adhesion to Hydroxyapatite Surfaces

Small salivary phosphoproteins--statherin (ST) and histatin 1 (HT1) - are found in the acquired enamel pellicle which modulates Streptococcus mutans adhesion onto dental enamel. However, their roles in S. mutans adhesion onto enamel surfaces are still undefined. The aim of this study was to investigate whether and how ST and HT1 affect (i) S. mutans adhesion and (ii) the adsorption of S. mutans adhesion-promoting salivary proteins onto hydroxyapatite (HA) in vitro. We fractionated human parotid saliva by adsorption to HA and further by gel filtration chromatography. Adhesion of [3H]-labeled S. mutans strain MT8148 onto sintered HA plates was promoted significantly (>10-fold) by high-molecular weight glycoprotein fraction (HMWGP), but not by purified ST or HT1. More interestingly, promotion of S. mutans adhesion onto HA by HMWGP was significantly reduced by adding purified ST or HT1 to HMWGP. [3H]-labeled S. mutans adhesion on HA was positively correlated to the [14C]-labeled HMWGP adsorption onto HA, which was also reduced by the addition of purified ST and HT1. Synthetic peptides corresponding to ST and HT1 reduced the parotid saliva-promoted S. mutans adhesion. However, removal of the negative charges in the N-terminal domains of ST and HT1 diminished their inhibitory effects on S. mutans adhesion promoted by parotid saliva. We conclude that ST and HT1 competitively inhibit the adsorption of salivary HMWGP, and thereby reduce S. mutans adhesion onto HA surfaces.

Sucrose substitutes and their role in caries prevention

Many non- or low-cariogenic sucrose substitutes are currently available and are found as ingredients of a variety of candy, chewing gum, and drinks. Recently the role of sugar alcohols in promoting remineralisation of enamel has attracted much attention. Thus, the dental profession needs to understand the general characteristics and features of sugar substitutes to provide advice on oral health to patients as well as the general public. There are two critical requirements for sucrose substitutes, namely, being nutritionally appropriate and not being detrimental to the overall general health of the individual. The use of a greater variety of confectionary containing sucrose substitutes and the development of new substitutes with high nutritional value are essential in the battle against caries. In this paper we review in detail the characteristics of sucrose substitutes currently in use, their role in caries prevention and promotion of oral health.

Reduction of saliva-promoted adhesion of Streptococcus mutans MT8148 and dental biofilm development by tragacanth gum and yeast-derived phosphomannan

The aim of this study was to investigate materials which reduce saliva-promoted adhesion of Streptococcus mutans onto enamel surfaces, and their potential in preventing dental biofilm development. The effects of hydroxyapatite (HA) surface pretreatment with hydrophilic polysaccharides on saliva-promoted S. mutans adhesion in vitro and de novo dental biofilm deposition in vivo were examined. Saliva-promoted adhesion of S. mutans MT8148 was significantly reduced by pretreatment of the HA surface with tragacanth gum (TG) and yeast-derived phosphoglycans. Extracellular phosphomannan (PM) from Pichia capsulata NRRL Y-1842 and TG reduced biofilm development on lower incisors in plaque-susceptible rats when administered via drinking water at concentrations of 0.5% and 0.01%, respectively. The inhibitory effect of TG on de novo dental biofilm formation was also demonstrated when administered via mouthwash in humans. It is concluded that TG and yeast-derived PM have the potential for use as anti-adherent agents and are effective in reducing de novo dental biofilm formation.

Relationship between Number of Present Teeth and Nutritional Intake in Institutionalized Elderly

We conducted oral examinations and dietary surveys on a total of 141 subjects with an average age of 80 years or more-specifically, seniors (S-group) living in a health service facility for the elderly and patients with mild dementia (SD-group) living in a special nursing home for the elderly. All were assumed to have a roughly uniform diet. We investigated which factors contributed to their dietary intake, and the relationship between dietary intake and number of present teeth (PT). Factors affecting total energy of the subjects and those in the S-group were body weight and number of PT. No factors were recognized as having a relationship with total energy in the SD-group. A significant difference was found in males in the S-group in that those in the "five PT or more" group had higher levels of carbohydrates and vitamin B1) than those in the "four PT or less" group. However, significant differences were found in the SD-group in that subjects in the "five PT or more" group had higher levels of carbohydrates, calcium, iron, and vitamins A, B1, B2, and C than those in the "four PT or less" group. Significant differences were seen in both groups for female patients in the nursing home with regard to total energy, proteins, carbohydrates, iron, vitamin B1, and fiber intake. No significant differences were recognized, however, for females in the SD-group. Reductions in dietary intake should be considered from the perspective of nutritional status, which is a problem that can be resolved through dental treatment. This study found that recovery of chewing ability in seniors was essential not only to maintain nutritional status, but also to fully bring out all the functions of the foods themselves.

Percentile Curves for Food Acceptance Response Scores in Assessing Chewing Functions in Adults

The purpose of this study was to evaluate whether percentile curves for food acceptance response scores were useful in assessing oral and occlusal conditions. We used data obtained from Chiba City Patient Surveys (males: 1,276, females: 1,381, aged 20 to 64), which were conducted in 1998 and 1999. Subjects were assigned scores of between 1 and 4 for 31 different kinds of food based on their food acceptance responses. Occlusal conditions were measured with pressure-sensitive sheets. We calculated the percentile values from 5 to 95 at intervals of five years. We divided the subjects into two groups at the twenty-fifth percentile and statistically analyzed various oral conditions in the two groups. Significant differences were found between them in the mean numbers of present, sound, and missing teeth for almost all age groups. Moreover, there were significant differences in tooth-contact area and occlusal force between the two groups. The results of multiple regression analysis revealed that the scores had a stronger correlation with occlusal conditions than number of teeth in 55-year-olds, although the effect teeth-factors had on scores was more significant in 45- to 50-year-old males. Females' scores had a stronger correlation with occlusal conditions than number of teeth in all age groups. These results indicate that the questionnaire on the acceptance of 31 different kinds of food is useful in providing a basis for oral health instruction and dental treatment aimed at improving chewing ability in adults.

Salivary flow and its relationship to oral signs and symptoms in patients with dry eyes

OBJECTIVES

The aim of this study was to investigate oral symptoms and clinical parameters in dry eye patients. Subjective reports of the sensation of a dry mouth, salivary flow rates, and clinical parameters of oral disease related to three different types of dry eye patients were examined.

SUBJECTS AND METHODS

There were 224 individuals, including dry eye patients and control subjects. The dry eye patients were classified into three types: patients with Sjögren's syndrome (SS-DE), patients without SS-DE (non-SS-DE), and patients with Stevens-Johnson syndrome (SJS-DE). Salivary flow rates were measured using two kinds of sialometry. Subjective and objective oral symptoms and signs were also examined.

RESULTS AND CONCLUSION

Over half of the dry eye patients complained of a dry mouth. The flow rates of their stimulated whole saliva and parotid saliva were significantly lower than those of the control groups (P < 0.05, P < 0.01). The sensation of a dry mouth and changes in oral soft tissues, dental caries, and oral Candida frequently occurred in dry eye patients.

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.

Relationship Between Oral Health Behaviors and General Health Behaviors in a Japanese Adult Population

OBJECTIVE

The aim of this study was to analyze the relationship between oral health behaviors and general health behaviors in adults.

METHODS

A total of 2,467 adults (1,208 men and 1,259 women aged 20-59 years) who consulted dentists in Chiba City were administered a questionnaire.

RESULTS

Women, older participants, and those living with family had better health behaviors than the other subjects studied. Additive indices for oral and general health behaviors were significantly correlated. Toothbrushing frequency was significantly correlated with five items of general health behavior (smoking, drinking, exercise, eating breakfast, and having medical check-ups). Having dental check-ups was significantly correlated with having medical check-ups. There was a negative correlation between dental flossing and drinking.

CONCLUSIONS

Of all oral health behaviors examined, toothbrushing frequency was the most predictive indicator of general health behavior.