Search

In Japan, with the increasing prevalence of gastroesophageal reflux disease (GERD) and growing public interest, the Japanese Society of Gastroenterology issued Evidence-based Clinical Practice Guidelines for GERD (1st edition) in 2009 and a revised 2nd edition in 2015. A number of studies on GERD were subsequently conducted in Japan and abroad, and vonoprazan, a potassium-competitive acid blocker (P-CAB), became available for the first time in Japan in February 2015. The revised 3rd edition (Japanese edition), which incorporates new findings and information, was published in April 2021. These guidelines are summarized herein, particularly sections related to the treatment of GERD. The important clinical issues addressed in the present revision are (i) the introduction of treatment algorithms that classify GERD into reflux esophagitis and non-erosive reflux disease, (ii) the clarification of treatment algorithms based on to the severity of reflux esophagitis, and (iii) the positioning of vonoprazan in the treatment for GERD. The present guidelines propose vonoprazan as the initial/maintenance treatment for severe reflux esophagitis. They also recommend vonoprazan or PPI as an initial treatment for mild reflux esophagitis and recommended PPI and proposed vonoprazan as maintenance treatment. These updated guidelines offer the best clinical strategies for GERD patients in Japan and hope that they will be of global use for the diagnosis and treatment for GERD.

To evaluate the prevalence of non-carious cervical lesions (NCCLs) on teeth with or without erosive etiological factors across a broad range of ages of Japanese adults. The study sample consisted of a total of 1108 subjects aged 15 to 89 years in Tokyo, Japan. Two examiners evaluated NCCLs and dental erosion (DE) during a full-mouth examination. Subjects were asked to complete a self-administered daily diet, habits, and health condition questionnaire. Subjects who had frequent acid consumption or gastric reflux and at least one tooth with initial enamel wear were placed in the erosion present (EP) group, and the remainder of subjects were placed in the erosion not present (EN) group. Logistic regression analyses were carried out to identify etiological factors of NCCLs associated with DE. Overall prevalence of NCCLs was 60.2%; the prevalence increased with age. There were no statistical differences in the prevalence of NCCLs between the EP and EN groups, except for the 60–69 years group. Multiple logistic regression analysis showed the frequency of consumption of carbonated soft drinks, citrus juice, and acidic fruits such as oranges; tooth brushing pressure; and bruxism were associated with the presence of NCCLs. There were no statistical differences in the prevalence of NCCLs with or without erosive etiological factors except for the 60–69 years group. NCCL distribution increased with age, and erosive risk factors caused by change in dietary habits might affect the incidence of NCCLs for elders. UMIN000041982

Salivary secretion in patients with proton-pump inhibitor (PPI)-resistant severe reflux esophagitis has not been examined. In this study, saliva secretion and salivary epidermal growth factor (EGF) in patients with PPI-resistant severe reflux esophagitis were investigated. We recruited 22 PPI-resistant and 22 PPI-responsive severe reflux esophagitis patients who were not infected with Helicobacter pylori. Saliva secretion testing and esophageal manometry using high-resolution manometry were performed. Saliva secretion was assessed as follows: each patient chewed sugar-free gum for 3 min prior to endoscopy and the amount and pH of saliva as well as the pH of saliva after acid loading as an index of the acid-buffering capacity were measured. The salivary EGF concentration was assessed by ELISA. The amount of saliva secreted was significantly lower in the PPI-resistant group than in the PPI-responsive group, with medians (25th-75th percentile) of 3.7 (2.2–6.8) and 4.9 (4.0–7.8) mL, respectively (p = 0.029). Salivary pH was significantly lower in the PPI-resistant group [6.9 (6.7–7.2)] than in the PPI-responsive group [7.2 (7.1–7.4), p = 0.001]. Salivary pH after acid loading was significantly lower in the PPI-resistant group [5.6 (5.3–5.9)] than in the PPI-responsive group [6.4 (6.1–6.5), p = 0.002]. The salivary EGF concentration was significantly higher in the PPI-resistant group [3211.5 (1865.0–4121.5)] than in the PPI-responsive group [1816.0 (1123.5–2792.3), p = 0.041]. No significant differences were observed in the proportion of esophageal motility abnormalities. Stimulated saliva secretion was reduced in PPI-resistant severe reflux esophagitis patients.

There is no consensus on the relationship between saliva secretion and non-erosive reflux disease (NERD). In this study, saliva secretion and salivary epidermal growth factor (EGF) in patients with NERD were examined. Thirty-one PPI-responsive NERD patients and 31 control subjects were recruited for this case–control study. Saliva secretion testing was performed. Saliva secretion was assessed as follows: each patient chewed sugar-free gum for 3 min prior to endoscopy, and the amount and pH of saliva before and after acid loading as an index of the acid-buffering capacity were measured. The salivary EGF concentration was assessed by ELISA. The amount of saliva secreted was significantly lower in the NERD group than in the control group, with medians (25th–75th percentile) of 4.0 mL/3 min (2.0–6.0) and 6.0 (3.9–8.0), respectively (p = 0.0131). Salivary pH was significantly lower in the NERD group (7.0 [6.8–7.2]) than in the control group (7.2 [7.0–7.3], p = 0.0100). Salivary pH after acid loading was significantly lower in the NERD group (5.8 [5.4–6.2]) than in the control group (6.3 [6.1–6.5], p = 0.0002). The difference in pH of stimulated saliva after acid loading (1.2 [0.9–1.5], p = 0.0021) was significantly higher in the NERD group than in the control group (0.8 [0.7–1.1]). The salivary EGF concentration was significantly higher in the NERD group (2513.0 pg/mL [1497.5–5005.0] than in the PPI-responsive group (1641.0 [1139.8–2092.0], p = 0.0032). Stimulated saliva secretion was reduced in PPI-responsive NERD patients.

A chairside tool for quantitative analysis of dental caries would improve clinical dental inspections. The wireless caries sensing tool with dental-explorer size has been developed comparing two sensing methods, Raman reading and pH reading for evaluating dental caries. The Raman spectra at 575 cm−1 and 960 cm−1 for in inorganic compounds, as well as 1450 cm−1 and 2940 cm−1 for organic compounds reinforced and supported the pH results. An Iridium/Iridium oxide (Ir/IrOx) pH sensing probe and wireless pH sensor (comprising an ESP8266 ESP-01 wireless module and ADS1115 analog digital converter) has been developed to quantitatively evaluate dental caries. All the operations of the wireless pH sensor were performed with a developed LabVIEW-based real-time data monitoring program. The slope and the linear fitting regression value (R2) of the wireless pH sensor using seven standards were −54.9 mV/pH and 0.999, respectively, showing high accuracy and stability for the pH measurements. The pH on the dental caries surface was measured with the wireless pH sensor, and the pH mapping results in the non-caries and caries areas were 6.9 and 5.7, respectively. The developed wireless pH sensor would be useful to understand the condition of dental caries and support dentists’ inspection to remove only the caries part while keeping the non-caries structure.

The aim of this study was to evaluate factors associated with the incidence of erosive tooth wear (ETW) among adults at different ages in Tokyo using multifactorial logistic regression analysis. The study sample consisted of a total of 1108 subjects aged 15 to 89 years in Tokyo, Japan. Two examiners evaluated ETW in a full-mouth recording. The subjects were asked to complete a self-administered daily diet, habit, and health condition questionnaire. Subjects who had frequent acid consumption or gastric reflux and at least one tooth with initial enamel wear were placed in the ETW-positive group, and the remainder of the subjects was placed in the ETW-negative group. Logistic regression analyses were carried out to identify factors collectively associated with ETW. Logistic regression analysis showed that greater frequencies of carbonated or sports drink consumption were associated with higher incidence of ETW for all age groups except for 70–89 years. Adults in the 30–39-year group who reported suffering from heartburn were about 22.3 times more likely to develop ETW, while 40–49-year adults who had repeated vomiting were about 33.5 times more likely to exhibit ETW compared with those who did not experience vomiting. Age-specific dietary habits were clearly observed among adults at different ages in Tokyo, and there were significant differences in intrinsic and extrinsic factors between ETW-positive and ETW-negative groups for each age group. Both greater frequency of carbonated and sports drink consumption were associated with higher incidence of ETW among adults at different ages in Tokyo.

Background The aim of this randomized controlled study was to evaluate the clinical performance of a highly filled flowable composite compared to a conventional paste-type composite in direct posterior restorations after 36 months. Methods A total of 58 mid-size to extensive posterior composite restorations were randomly placed in 32 patients, mean age of 43.9 years (range 25–76), using either a conventional composite Estelite Sigma Quick (Conventional) or a highly filled flowable composite G-aenial Universal Flo with a two-step self-etch adhesive. The restorations were evaluated after placement (baseline) and at 6, 12, 24 and 36 months according to the FDI criteria. Results At the 36-month follow-up, 42 restorations were evaluated in 21 patients. After 36 months, the difference between highly filled flowable and conventional restorations was not statistically significant with respect to all evaluation parameters (p < 0.05). No secondary caries was observed. Conclusions The highly filled flowable composite showed a comparable clinical effectiveness as the conventional paste composite in posterior restorations over 36 months.

Dental erosion is defined as the pathologic, chronic, localized loss of dental hard tissue caused by the exposure of tooth surfaces to extrinsic or intrinsic acids, not related to bacterial metabolism. The main intrinsic factor is regurgitated gastric acid, while extrinsic factors are acidic industrial vapors or dietary components such as acidic drinks and foods. In recent epidemiological study in Japan, 26.1 % of 1,108 subjects were placed in dental erosion. For case of physiological wear, particularly where there may be no aesthetic or functional det- riment, or any associated symptoms of discomfort, management strategies may be limited to prevention with dietary counselling and monitoring only. In contrast, those with patho- logical wear may be in need of restorative treatments using resin composites.

To assess the remineralization capacity of carious, non-carious, and combined white spot lesions (WSLs) using the ICDAS and SS-OCT.This clinical trial was based on a quasi-experimental design. Forty-two healthy subjects (median age 26.6 years), who visited university hospital and had at least one WSL with an ICDAS score of 2 or 1, were recruited. The subjects chewed a non-blind sugar-free gum containing bioavailable calcium and fluoride for 3 months. The remineralization capacities of carious and non-carious 121 WSLs were assessed using ICDAS by two calibrated non-blind examiners and optical boundary depth (BD) by SS-OCT at a monthly recall. The outcome variables, transitions of ICDAS score, mean BD, and mean BD recovery rate (RR%), were statistically analyzed using the chi-square test, two way-repeated measures ANOVA, and Wilcoxon rank sum test, respectively (alpha = 0.05).Based on the visual inspection, OCT images at the baseline, 72 WSLs were purely carious, 20 were non-carious (developmental) lesions, while 29 were combined (carious-developmental). The responses of WSLs over time showed to be highly variable. There was a significant difference in transitions of ICDAS scores after 3 months between carious and non-carious WSLs (p 0.05) and non-carious and combined WSLs (p 0.05). Carious and combined WSLs underwent significant changes in the mean BD between baseline (161.8 ± 56.8 μm) and 2 months (130.7 ± 57.4 μm) or 3 months (119.1 ± 57.5 μm) (p 0.05), while there was no significant difference between baseline (132.2 ± 26.2 μm) and 2 months (122.8 ± 24.1 μm) or 3 months (119.8 ± 22.6 μm) in non-carious WSLs (p 0.05). There was a significant difference in mean RR% after 2 and 3 months between carious and non-carious WSLs (p 0.05).The remineralization capacity of WSL was variable among the cases and subjects, and depended on the WSLs history, etiology (carious, non-carious, or combined lesion) and structure (histological pattern).Carious WSLs showed the highest remineralization potential.

To evaluate the prevalence of erosive tooth wear on buccal, incisal/occlusal and palatal/lingual surfaces in a wide age range of Japanese adults.The study included a total of 1108 adults aged 15 to 89 years in Tokyo, Japan. The subjects were asked to complete a self-administered nutrition-related questionnaire. Two examiners evaluated tooth wear on the buccal, occlusal/incisal and palatal/lingual surfaces in a full-mouth recording, using a modified Smith and Knight tooth-wear index. Subjects who frequently consumed acidic beverages or food, or had gastric reflux and at least one tooth with an initial enamel smooth-surface wear facet were placed in an erosion-positive group, and the rest of subjects were placed in the erosion-negative group.26.1% of the participants were placed in the erosion-positive group. For buccal surfaces, advanced wear progression was predominantly observed on maxillary and mandibular anterior teeth, especially in the youngest age group (15-39 years). On incisal/occlusal surfaces, early dentin exposure was observed in the middle age group (40-49 years) in the erosion-positive group. For palatal/lingual surfaces, wear progression was mainly observed on maxillary anterior teeth among 30- to 39-year olds and 50- to 59-year-old in the erosion-positive group, but that prevalence was lower than for the other tooth surfaces.For all age groups of Japanese adults, the prevalence of erosive tooth wear depended on tooth types and surfaces.

This study aimed to evaluate the susceptibility of cut and uncut enamel surfaces to an erosive challenge and to examine the resultant characteristics/morphological changes. Ten extracted human incisors were used for preparation of enamel samples, and samples were immersed in citric acid. After 3 (total 3 min) and 6 cycles (total 6 min) of erosive challenges, surface loss (SL) and morphological changes were measured using scanning microscopy and FIB-TEM. Ca release (CA) and surface hardness (SH) were measured using a calcium-sensitive electrode and hardness tester respectively. Mean values of all measurements were statistically analyzed by using a t-test. Uncut enamel samples had significantly lower SL and greater SH than cut enamel (p

This in situ study aimed to evaluate effects of waiting periods after erosive challenge before toothbrushing on enamel abrasion and nanoindentation hardness. Ten subjects wore intraoral appliances each with a set of 4 bovine enamel blocks. The enamel blocks were subjected to 2 cycles a day for 3 days as follows; intraoral exposure to form acquired pellicle and extraoral erosion followed by either 0, 3, 30 or 60 min intraoral exposure and then brushing, which was performed using an automatic brushing machine. Abrasive loss was assessed by white light interferometry. Nanoindentation was performed to calculate relative hardness. Abrasion and relative hardness were statistically analyzed by ANOVA. Abrasive loss was significantly less in groups exposed to saliva compared with 0 min (p0.05); there was no significant difference between 30 and 60 min (p0.05). Relative hardness was statistically higher after intraoral exposure, but no differences existed among any intraoral exposure periods (p0.05).

To assess the effect of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and fluoride on white spot lesion (WSL) remineralization in comparison with POs-Ca or placebo (control) chewing gums, in double- blind, randomized, controlled trial.Thirty-seven healthy subjects, who had at least one WSL, with an ICDAS score of 2 or 1, were recruited for this study. The subjects were randomly divided into three groups (control, POs-Ca, POs-Ca+F) and chewed two slabs of each gum three times every day for 3 months. WSLs were assessed using ICDAS criteria and optical boundary depth (BD) by optical coherence tomography (OCT) system at a monthly recall. Data were analyzed by Wilcoxon rank-sum test and Wilcoxon signed rank test with Bonferroni corrections at 0.05 significance level.Visual score changes from ICDAS score 2 to score 1 over the course of the study were observed; control (30%), POs-Ca (48%) and POs-Ca+F (45%). Unlike the control gum, chewing POs-Ca and POs-Ca+F gums resulted in significant changes in the mean value of BD over the 3 months course of the study (p0.05). There was a significant difference in mean value of BD after first month between POs-Ca+F and control groups (p0.05).This study highlighted the importance of calcium and fluoride ion bioavailability in the reinforcement of demineralized enamel lesions by chewing gums. Furthermore, adding fluoride to POs-Ca might speed up the remineralization progress on natural WSL.

Manufacturers are adding fluoride (F) to calcium-containing chewing gums to further promote enamel remineralization. The aim of this study was to assess the effect of a chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and fluoride on remineralization of enamel subsurface lesions, in a double-blind, randomized controlled in situ trial.Thirty-six volunteer subjects wore removable buccal appliances with three different insets of bovine enamel with subsurface demineralized lesions. For 14 days the subjects chewed one of the three chewing gums (placebo, POs-Ca, POs-Ca+F), three times a day. After each treatment period, the insets were removed from the appliance, embedded, sectioned, polished and then subjected to laboratory tests; mineral level was determined by transverse microradiography (TMR; n=36), and hydroxyapatite (HAp) crystallites were assessed by synchrotron radiation wide-angle X-ray diffraction (WAXRD; n=13). Data were analysed by t-test or Wilcoxon rank-sum test with Bonferroni corrections at 0.05 significance level.Chewing POs-Ca and POs-Ca+F gums resulted in 21.9±10.6 and 26.3±9.4 (mean±SD) percentage mineral recovery, which was significantly higher than that of placebo gum (15.0±11.4) (p0.05). Chewing POs-Ca+F gum resulted in 24.9±5.4 (mean±SD) percentage HAp crystallites recovery, which was significantly higher compared to POs-Ca (16.0±4.1%) or placebo (11.1±4.8%) gums (p0.05).Addition of POs-Ca to the chewing gum resulted in significant remineralization of enamel subsurface lesions. Although POs-Ca+F gum was not superior in TMR recovery rate when compared with POs-Ca gum, WAXRD results highlighted the importance of fluoride ion bioavailability in the formation of HAp crystallites in enamel subsurface lesions in situ (NCT01377493).

Objectives To evaluate the pretreatment effect of mild acidic HOCl solution on the microtensile bond strength (μTBS) of a two-step self-etch adhesive to dentin and the alteration of dentin surface pH. Methods Thirty-nine flat ground coronal dentin specimens were divided into one control group and 12 experimental groups, which were treated with 6% NaOCl or 50, 100 and 200 ppm HOCl (Comfosy ® ) solutions for 5, 15 and 30 s. After rinsing with running water for 30 s, all the dentin surfaces were bonded with Clearfil SE Bond according to the manufacturer's instructions. After 24 h water storage, the bonded specimens were sectioned and trimmed to an hourglass shape with a cross-sectional area of approximately 1.0 mm 2 and then subjected to the μTBS test. Thirty-six mid-coronal dentin discs were used for surface pH measurement. Dentin surface pH with or without pretreatment was examined using a pH-imaging microscope (SCHEM-100). The μTBS data were analyzed by one-way ANOVA (Dunnett's T3) and the surface pH data were analyzed by non-parametric statistics (Mann–Whitney U -test). Results Pretreatment with Comfosy ® at concentrations of 50, 100 and 200 ppm did not significantly affect μTBS regardless of the application time compared with the control group, however the 100 and 200 ppm Comfosy ® groups showed significantly lower surface pH values. For the NaOCl pretreatment groups, a longer application time significantly decreased the μTBS and increased the surface pH values compared to the control group. Conclusions The 50 ppm Comfosy ® pretreatments for 5, 15 and 30 s did not affect the μTBS of the two-step self-etch adhesive to dentin and dentin surface pH.

Objective The aim of this study was to adapt a quantitative test for stimulated saliva, known as the Checkbuf test, to measure the buffering capacity of resting saliva and to evaluate its correlation with the Ericsson test for resting saliva. Study design Resting saliva was collected from 112 patients. Buffering capacity was assessed with the adapted Checkbuf test and 4 other methods: Ericsson test for resting saliva, Checkbuf test, and commercially available paper and liquid colorimetric tests for stimulated saliva. Data were analyzed by Cohen kappa coefficient to evaluate the agreement between the Ericsson test and the other tests. Results There was a significant positive agreement between the Ericsson test for resting saliva and adapted Checkbuf test (κ = 0.708). However, there were no agreements between the Ericsson test and the 3 other tests. Conclusions This study demonstrated that the adapted Checkbuf test is useful for measuring resting saliva buffering capacity, even for subjects with low salivary flow rates.

The purpose of this study was to evaluate the micro-shear bond strengths and the etching efficacy of a two-step self-etching adhesive system to fluorosed and non-fluorosed enamel. The extracted teeth, obtained from Australian and Japanese patients, were classified according to the severity of fluorosis, using the Thylstrup & Fejerskov index (TFI). Australian teeth were classified as mildly fluorosed (TFI = 1-3), whereas Japanese teeth were classified as non-fluorosed (TFI = 0). Resin composite was bonded to 20 enamel samples using Clearfil SE bond. The bonded samples were stressed at a crosshead speed of 1 mm min(-1) to determine the micro-shear bond strength. To examine the etching efficacy of primer on fluorosed and non-fluorosed enamel, the enamel-surface pH values were directly measured using a micro pH sensor. The non-fluorosed enamel showed significantly higher bond strengths compared with the fluorosed enamel. There was a statistical difference between fluorosed and non-fluorosed enamel regarding the surface pH change before and after application of the Clearfil SE bond primer. The results from this study suggest that water fluoridation has an effect on the acid resistance of enamel surfaces when treated with a two-step self-etching adhesive system and that this effect leads to reduced bond strengths.

Background: The ion activity product for hydroxyapatite (IpHA) is a comprehensive parameter reflecting pH, calcium and phosphate ion concentration in saliva which govern the degree of saturation with respect to the dissolving tooth mineral. The aim of this study was to evaluate the relationship between quantitative assessments of salivary buffering capacity and IpHA in relation to cariogenic potential. Methods: Stimulated whole saliva was collected from 33 patients, and the initial pH of samples was measured using a hand-held pH meter. Then samples were titrated with 0.1 N HCl to evaluate buffering capacities and divided into three groups (high, medium and low). After measuring concentrations of calcium and phosphate ions in the samples, IpHA was calculated using the values of the ion concentrations and pH. Differences in the mean pH values, the concentrations of calcium, phosphate ions and log[IpHA] among three groups were analysed using the Kruskal Wallis and the Mann-Whitney non-parametric test, p

This study aimed to assess swept source optical coherence tomography (SS-OCT) for in vitro and in vivo detection of enamel white spot lesion (WSL). WSLs without surface breakdown on 33 extracted human posterior teeth were non-invasively scanned using SSOCT. The teeth were then cross-sectioned and imaged under confocal laser scanning microscope (CLSM) and light microscopy (LM). SS-OCT cross-sectional images were compared with CLSM and LM. WSL shapes in SS-OCT images closely corresponded to those of LM. There were significant correlations (p0.001) in WSLs depth between SS-OCT and LM (r=0.92), SS-OCT and CLSM (r=0.80) and CLSM and LM (r=0.85). Six WSLs were also evaluated clinically using SS-OCT; clear in-depth images of these natural WSLs were obtained in vivo. SS-OCT appears to be an effective tool for observation of the internal structure of WSLs, enabling quantitative assessment of WSL depth. Such data can be considered in the clinical management of WSLs.

To evaluate salivary flow rate and buffering capacity using a quantitative pH measurement among three broad age groups.The population consisting of 117 patients was classified into three age groups: young, middle-aged, and elderly group. The volume of stimulated saliva after chewing gum was measured. Saliva samples were titrated with 0.1N HCl to evaluate the buffering capacity. Saliva pH change was measured directly using a hand-held pH meter. At the point of 50 microL of titrated HCl, individual salivary buffering capacities were ranked into one of the following three categories; high buffering capacity (above pH 5.5), medium buffering capacity (from pH 5.5 to 4.5), and low buffering capacity (below pH 4.5).Chi(2)-test showed that the proportional distribution of individuals in the three buffering capacity groups was not statistically different among the age groups (p0.05). One-way ANOVA and Tukey's HSD test showed the flow rate of stimulated whole saliva in the young group was significantly greater than that of the middle-aged and elderly groups (p0.05). Two-way ANOVA showed there was no significant interaction between the independent variables buffering capacity and age group (F=0.419, p=0.7950). One-way ANOVA and Tukey's HSD test indicated the flow rate showed significant differences among the three age and buffering capacity groups.Although a limited number of subjects were investigated in this study, the quantitative saliva assessment is useful as a screening method for different ages to identify patients with a low saliva flow rate and/or buffering capacity.

The aim of this study was to evaluate the pH at the surface of active or arrested carious dentin using a micro pH sensor, and to compare the relationship between different pH measurement techniques. Twenty extracted carious teeth were divided into two groups, active or arrested caries, according to predefined clinical criteria before extraction. The surface pH values of carious dentin were measured using three methods: surface pH directly measured using a micro pH sensor (Direct); sectioned teeth measured using a pH-imaging microscope (Imaging) or micro pH sensor (Slice). For all techniques, statistically significant differences in pH values were observed between active and arrested dentinal caries (p

The aim of this study was to evaluate the microtensile bond strength (microTBS) and the elemental contents of the adhesive interface created to normal versus caries-affected dentin. Extracted human molars with coronal carious lesions were used in this study. A self-etching primer/adhesive system (Clearfil Protect Bond) was applied to flat dentin surfaces with normal and caries-affected dentin according to the manufacturer's instructions. After 24 h water storage, the bonded specimens were cross-sectioned and subjected to a microTBS test and electron probe microanalysis for the elemental distributions [calcium (Ca), phosphorus (P), magnesium (Mg), and nitrogen (N)] of the resin-dentin interface after gold sputter-coating. The microTBS to caries-affected dentin was lower than that of normal dentin. The demineralized zone of the caries-affected dentin-resin interface was thicker than that of normal dentin (approximately 3 microm thick in normal dentin; 8 microm thick in caries-affected dentin), and Ca and P in both types of dentin gradually increased from the interface to the underlying dentin. The caries-affected dentin had lost most of its Mg content. The distributions of the minerals, Ca, P, and Mg, at the adhesive interface to caries-affected dentin were different from normal dentin. Moreover, a N peak, which was considered to be the collagen-rich zone resulting from incomplete resin infiltration of exposed collagen, was observed to be thicker within the demineralized zone of caries-affected dentin compared with normal dentin.

BACKGROUND An antibacterial self-etching primer has been developed to inhibit bacterial attachment and plaque accumulation on the tooth surfaces. The purpose of this study was to evaluate the growth-inhibitory effect of an antibacterial self-etching primer on mutans streptococci obtained from arrested carious lesions. MATERIALS AND METHODS Softened dentin specimens were obtained from arrested carious lesions with an excavator or a round steel bur. The effect of a commercial antibacterial self-etching primer and a commercial self-etching primer on the total streptococci on Mitis-Salivarius (MS) agar plates and on Streptococcus mutans on MS agar plates containing 0.02 M bacitracin (MSB) was evaluated. Specimens with no primer were used as controls. The number of colonies of both total streptococci and S. mutans were compared statistically with two-way analysis of variance and Fisher's Protected Least Squares Differences (PLSD) test (p < .05). RESULTS The number of colonies of total streptococci (CFU/mL) for the two methods (excavator and round steel bur) were as follows: for the control, 5.0 x 10(6) and 5.0 x 10(6); for the self-etching primer, 1.0 x 10(5) and 1.0 x 10(5); and for the antibacterial self-etching primer, 0 and 0. The number of colonies of S. mutans for the two methods (excavator and round steel bur) were as follows: for the control, 5.0 x 10(6) and 1.8 x 10(5); for the self-etching primer, 3.5 x 10(4) and 5.0 x 10(3); and for the antibacterial self-etching primer, 0 and 0. Regardless of the method of softened dentin removal, the antibacterial effect was significantly higher for the group that had antibacterial self-etching primer compared with that of the control group and the group that had commercial self-etching primer (p < .05). CLINICAL SIGNIFICANCE The antibacterial self-etching primer showed a high level of antibacterial activity against mutans streptococci obtained from the arrested carious lesions.

The aim of this in vitro study was to evaluate the pH value of intact and carious dentin in primary teeth using a pH-imaging microscope (SCHEM-100, HORIBA Ltd., Kyoto, Japan). Bucco-lingual cut sections of extracted human primary teeth, which had either mild or severe dentinal caries lesions, were placed on the pH-imaging sensor of the microscope. The pH values were compared statistically by Levene's test for equality of variances and Tukey HSD multiple comparison test (p < 0.05). For both mild and severe lesions in primary dentin, the lowest pH values in the carious lesions were lower than those of intact dentin (6.6, range 6.3-6.9). There were statistical differences between the lowest pH value within the mild lesions (6.2, range 5.8-6.4) and that of the severe lesions (6.0, range 5.9-6.2) (p < 0.05). It was concluded that SCHEM-100 was able to distinguish the pH-value distribution of intact and carious dentin in primary teeth.

This study examined the relationship between a ceramic primer and ceramic surface pH on the microtensile bond strength of dual-cure resin cement to ceramic.Ceramic blocks (Vita Celay Blanks) were cut into multiple 3mm-thick slices and polished using 600-grit SiC paper. Two pairs were left untreated (controls), six pairs were treated with 40% phosphoric acid (PA), six pairs were treated with 20% hydrofluoric acid (HFA), and rinsed with water for either 15, 30 or 60 s. Half the specimens were silanated with Tokuso ceramics primer (TCP) (Tokuyama) and the other half with TCP formulated without phosphate monomer (TCP-NoPM). All the pairs were bonded with Bistite II dual-cure resin cement (Tokuyama) and light-cured. After 24 h water storage at 37 degrees C, the bonded specimens were cut into 6x0.7x0.7 mm(3) beams and their microtensile bond strengths (micro TBS) determined. Failure modes were determined using a confocal laser-scanning microscope. For scanning chemical analysis, the polished slices were cut into quarters, divided into seven groups of six, and treated in a similar manner as described for the micro TBS test. Surface pH was then determined using a scanning chemical microscope. For SEM examination, one ceramic quarter from each of the seven groups was used.Three-way ANOVA revealed that the micro TBS of TCP was significantly higher than TCP-NoPM with no acidic treatment (p0.05). However, after treatment of the ceramic surface with either PA or HFA, and 15 s rinsing, there was a significant reduction in surface pH (p0.05), and no significant difference in micro TBS between TCP and TCP-NoPM (p0.05). For TCP, there were no significant differences in micro TBS and failure mode between the control, PA, and HFA treated groups when the water rinsing time was increased. Whereas, for TCP-NoPM and surface treatment with PA, an increase in rinsing time resulted in a significant reduction in micro TBS and a significant increase in surface pH (p0.05).Acidic treatment of the ceramic surface did not significantly increase dual-cure resin/ceramic bond strengths when the ceramic primer, TCP, was used. It is suggested that when no phosphate monomer is present in a ceramic primer, dual-cure resin cement/ceramic bond strength is dependent upon the concentration of H(+) ions on the ceramic surface.

To evaluate the age-specific prevalence of erosive tooth wear in Japanese adults.The study sample consisted of a total of 1108 adults aged 15-89 yrs in Tokyo, Japan. The subjects were asked to complete a self-administered nutrition-related questionnaire. Two examiners evaluated tooth wear in a full-mouth recording, using a modified tooth wear index developed based on the Smith and Knight Tooth Wear index. Subjects who had frequent acid consumption or gastric reflux and at least one tooth with an initial enamel wear were placed in an erosive wear positive group, and the rest of subjects were placed in the erosive wear negative group.The median (IQR) prevalence of erosion was 19.1 (1.8) at enamel level and 6.5 (3.7) with dentin exposure. There were statistical differences in prevalence of erosive wear among different age groups (p0.05). Dietary habits found to be frequent in erosive wear positive group included acidic juices for younger subjects (15-39 yrs), and acidic fruits for older subjects (60-89 yrs). The prevalence of gastroesophageal reflux and eating disorder was 3.5%. A severe loss of dental tissue was observed on labial and incisal surfaces of anterior teeth in the erosive wear positive group.In the studied sample of Japanese adults, 26.1% had signs of erosive wear.Erosive wear, in combination with abrasion and attrition, results in severe loss of tooth tissue. Frequent consumption of acidic fruits and drinks was significantly associated with erosive tooth wear at different age groups.

The aim of this study was to assess the effect of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and a low concentration of fluoride (F) on the hardness of enamel subsurface lesions, utilizing a double-blind, randomized, and controlled in situ model. Fifteen individuals wore removable lingual appliances with 3 bovine-enamel insets containing subsurface demineralized lesions. Three times a day for 14 days, they chewed one of the 3 chewing gums (placebo, POs-Ca, POs-Ca+F). After the treatment period, cross-sectional mineral content, nanoindentation hardness, and fluoride ion mapping by time-of-flight secondary ion mass spectrometry (TOF-SIMS) were evaluated. Although there were no statistical differences in overall mineral content and hardness recovery rates between POs-Ca and POs-Ca+F subsurface lesions (p > 0.05), nanoindentation at 1-μm distance increments from the surface showed statistical differences in hardness recovery rate between POs-Ca and POs-Ca+F in the superficial 20-μm region (p < 0.05). Fluoride mapping revealed distribution of the ion up to 20 μm from the surface in the POs-Ca+F group. Nanoindentation and TOF-SIMS results highlighted the benefits of bioavailability of fluoride ion on reinforcement of the superficial zone of subsurface lesions in situ (NCT01377493).

Objectives A low pH environment is created by cariogenic bacteria. This study was aimed to measure pH of carious lesions intraorally using a micro-pH sensor, and assess predominant acid-producing cariogens by qPCR to differentiate caries activities. Methods 103 dentine lesions classified as active or arrested caries based on the clinical and radiological examinations were collected from patients after intraoral measurement of the lesion surface pH using a micro-pH sensor. Quantitative detection of genomic DNA copies of target cariogenic bacteria (mutans streptococci and Lactobacillus spp.) in each lesion was performed using real-time PCR. Correlation between the pH ranges and the number of bacterial species was examined by Spearman test. Results 50 samples were diagnosed as active and 53 as arrested lesions. Statistically significant difference was observed on average surface pH value between active and arrested lesions ( p Lactobacillus spp. was higher in active lesions than in arrested lesions (76% vs. 58% of samples, respectively). When the carious lesions were categorised into four different pH ranges (up to 5.5, from 5.6 to 5.8, from 5.9 to 6.1 and 6.2 or above), increased prevalence of Lactobacillus spp. was observed with decrease of pH levels. A significant negative relationship was found between pH value and number of Lactobacillus spp. ( r = −0.209, p Conclusions Intraoral pH measurement might be clinically useful to determine acidity of the local environment of carious lesions as one aspect of the caries activity assessment. Clinical significance The population of certain bacteria may indicate activity of carious lesions. Intraoral pH measurement of the carious lesions using a micro-pH sensor may be a clinically feasible method for assessment of lesion acidity.

The aims of this study were to clarify which steps in approximal restorative procedure were difficult for the final-year undergraduate students at Tokyo Medical and Dental University, and to examine the relationship between perception of difficulty and clinical experience. At mid-term of the clinical education experience, a self-questionnaire was performed by final-year undergraduate students to clarify the difficulty of restorative procedures at the time. There were statistically significant differences in the number of clinical cases experienced at the time between students who designated the matrix application, shade selection and finishing as the easy steps and those who considered them as the difficult ones (Fisher exact test with Bonferroni correction, p0.05). There was a significant difference in the total number of procedures designated as difficult between students who had treated above 15 cases and those who had fewer than 15 cases (Wilcoxon rank-sum test, p0.05). In the final-year clinical education for operative dentistry, students might need to treat over 15 cases to gain confidence in performing approximal composite restorations independently.

Objectives Means of objectively assessing white spot enamel lesions (WSEL) are critical for determining their potential activity and monitoring the success of preventive treatments. The aim of this study was to determine whether surface pH measurements of WSEL changed during a preventive course of care designed to remineralize the lesions. Methods Eight healthy subjects (1 male and 7 females) with at least one WSEL were recruited (19–64 years). Each subject was placed on a preventive treatment program including the daily application of a CPP-ACP paste (MI paste, GC Corp., Japan) with custom fitted trays for more than 6 months. The surface pH values of sound enamel and WSEL were monitored for up to 2 years using a micro-pH sensor. The visual appearance of the WSEL was monitored via digital photography, and images were analyzed qualitatively on a 5-point scale to assess the success of the remineralization preventive program. The relationship between the qualitative assessment of WSEL appearance and the WSEL pH was investigated using a Spearman's rho non-parametric correlation. Results The surface pH of the WSEL was different to that of the sound enamel surrounding it in all patients at all times. All lesions showed visual improvement as the treatment period progressed. The pH of the WSEL increased towards that of sound enamel over the course of treatment significantly correlating with the visual improvement of the lesion (rho = 0.63, p Conclusions The clinical assessment of WSEL surface pH changes with time may have utility as an additional objective measure for the assessment of WSEL activity.

To evaluate dental caries and periodontal pocketing in relation to saliva buffering capacity among two groups of Japanese adults aged above 35 years old (A35) or 35 years old and below (B35).After measuring the initial pH of saliva, samples were titrated with 0.1N HCl to evaluate the buffer capacity. Levels of mutans streptococci and Lactobacilli in saliva, DMF and periodontal pocket were also measured.Among B35 group, DMF of adults with High buffering capacity was significantly lower than those of adults with Medium and Low buffering capacity (p0.05). Chi-square test showed the distribution of subjects with high counts of mutans Streptococci or Lactobacilli into the three buffer capacities, which was not statistically different between two age groups (p0.05). There were statistical differences for the mean periodontal pocket depth on the upper right incisor of adults in A35 with High buffer capacity and those of adults with any buffer capacity in B35 group. Statistical differences were also found for the pocket depth on lower left incisor and upper right molars of adults in A35 with High buffer capacity and those of adults with low buffer capacity in B35 group (p0.01).High buffering capacity of saliva might be associated with better status of oral health among Japanese adults in both age groups.

Data on the adhesive strength of new all-in-one adhesives are still relatively limited. This study compared the microshear bond strengths of five recent all-in-one self-etching priming systems (G-Bond, One-Up Bond-F Plus, Clearfil S3 Bond, Adper Prompt L-Pop and Go!) with a widely used two-step self-etching priming system (Clearfil SE Bond). Human molars were sectioned and finished with 600-grit SiC paper. Both enamel and dentin were bonded using adhesives with a 0.7 mm bonding diameter. Bond strengths were tested using a microshear bond test method at a crosshead speed of 1 mm/minute. The mean bond strengths and standard deviations were calculated and analyzed using ANOVA and the Tukey's HSD test. Results showed the two-step self-etching system had significantly higher bond strengths to dentin. However, for enamel bond strength, Clearfil SE Bond showed no statistical difference to G-Bond and Go!; however, all of the other materials were statistically lower. It is necessary to examine these new materials clinically to determine their efficacy.

Background: In 1959, Ericsson developed a laboratory buffer capacity test. Because the Ericsson test is not practical for use as a chair-side test, commercially available saliva buffering capacity tests have been developed for use in the dental office. The purpose of this study was to evaluate the correlation between a modified Ericsson test and three commercially available quantitative and colourimetric tests. Methods: Stimulated saliva (by chewing paraffin wax) was collected from 113 patients. Individual saliva buffering capacity was assessed with the following four different methods: modified Ericsson test; quantitative test using a hand-held pH meter; paper strip; or liquid colourimetric test. The correlations of ranking results among the different tests were analysed using the Spearman Rank Correlation Test, p

To evaluate the effect of resin coating of bonded dentin on the micro-tensile bond strengths of a resin cement to dentin over 1 year.Human molars were ground to obtain flat dentin surfaces and divided into three groups. The dentin surfaces were left as a control, or resin-coated with a combination of a dentin bonding system, Clearfil SE Bond (SE), and one of two lining materials: Protect Liner F (PLF) (SE/PLF) or Ionosit Micro Spand (IMS). The dentin surfaces with or without resin coating were covered with a temporary filling material (Cavit-G) and stored in water for 1 day. After removal of Cavit-G, an indirect composite block (Estenia) was bonded with Panavia F following the manufacturer's instructions. The specimens were stored in water for 1 day, 6 months or 1 year in 37 degrees C water. Micro-tensile bond strength was measured at a crosshead speed of 1 mm/minute. There were 10 slices each group. Data were analyzed with two-way ANOVA and Fisher's PLSD test (P0.05).ANOVA indicated that resin coating and storage period significantly influenced the micro-tensile bond strengths (P0.0001). The bond strengths of SE/PLF, SE/IMS and the control after 1 day were 27.5 +/- 5.1, 15.7 +/- 3.2 and 10.6 +/- 4.9 MPa, respectively. The bond strengths of SE/PLF significantly decreased over 1 year (P0.05), while there were no significant differences in bond strengths for SE/IMS (P0.05). The bond strengths of SE/PLF were significantly higher than those of the control over 1 year (P0.05).

– A missing incisor or premolar tooth that requires a quick functional and esthetic repair, such as the case of tooth loss caused by trauma needs quick conservative treatment to maintain sound abutment teeth. The use of resin composite for direct fixed partial denture (FPD) can reduce problems associated with metal substructures, such as esthetic limitations and preparation of abutment teeth. However, mechanical failure of direct FPD often occurs because of design limitations and poor fabrication. This case report describes a direct resin composite FPD combined with an orthodontic wire framework. A small enamel dimple was prepared below the contact area, and a U-shaped wire was formed and positioned in the prepared enamel dimples and bonded with resin cements. An alloy primer was applied to the surface of the wire, which was coated with adhesive resin and veneered with resin composite. The finishing of the margins and final polishing were completed a week after insertion. The FPD was contoured using fine composite diamond finishing burs and polished with silicone points. The combination of the U-shaped wire and an enamel dimple below the contact area has shown good results over a period of more than 12 months in these two cases.

To assess the 10-year clinical performance of resin composite restorations placed using the acid-etch technique.Clinical evaluation of 58 resin composite restorations was performed by 9 operators of the Operative Dentistry Clinic of the Dental Hospital, Tokyo Medical and Dental University. Conservative preparations had been made and a total-etch adhesive system used for the resin composite restorations, which were placed in 1992 in the Operative Dentistry Clinic. Restorations were scored using the following scale: Alfa--good; Bravo--clinically acceptable; Charlie--clinically unacceptable; Delta-already replaced. The scores were analyzed using the chi-square test and the expected cell frequency (P = .05).The 58 restorations from 26 patients (13 men and 13 women) were identified in the treatment records and analyzed. Twenty-two restorations (37.9%) presented Alfa scores and 17 restorations (29.3%) were clinically acceptable (Bravo scores), while 3 restorations (5.2%) received Charlie scores and 16 restorations (27.6%) had already been replaced (Delta scores). The descending ranking of longevity by restoration type was Class 5Class 3Class 2Class 1Class 4 (P = .05).Of the restorations evaluated, 67.2% were ser-viceable (combined Alfa and Bravo scores) 10 years after placement. Longevity was significantly influenced by cavity type.

This study was conducted to assess the five-year clinical performance of composite restorations using a self-etching primer adhesive system, Clearfil Liner Bond II. Restorations were rated using the following scale: A - Good; B - Clinically acceptable; C - Clinically unacceptable; or D - Already replaced. The ratings were analyzed using Freedman's test (p=0.01) and Steel-Dwass test (p=0.05). A total of 83 restorations from 36 patients were identified from treatment records. Twenty-six restorations (31.3%) presented A rating and 36 restorations (43.4%) were clinically acceptable (B rating), while five (6.0%) received C rating and 16 (19.3%) had already been replaced (D rating). The mean survival rate of serviceable restorations (i.e., combined A and B ratings) after five years was 74.7%. It was found that cavity form, including cavity size, and occlusal contact seemed to influence longevity.

Background: Saliva collection can provide clinical information about individual patients. However, a correlation between ranking buffering capacity using resting and stimulated saliva is still unknown. The aim of this study was to evaluate the pH change after HCl titration into resting and stimulated saliva for a salivary buffering capacity test. Methods: Resting and stimulated saliva (by chewing paraffin wax) were collected from 80 patients. After the pH of both saliva samples was measured using a hand-held pH meter, the saliva samples were titrated with 0.1N HCl to evaluate the buffering capacity. Correlations of ranking buffering capacity (high, medium, low) between stimulated saliva and resting saliva with 30μL HCl titration and between stimulated saliva and resting saliva with 40μL HCl titration were statistically analysed by Spearman Rank Correlation Test (p < 0.05). Results: At 50μL HCl titration, stimulated saliva buffering capacities were ranked into high (above pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). At 30–40μL HCl titration, the resting saliva buffering capacities were ranked into the same categories. Spearman Rank Correlation indicated significant positive coefficients for the stimulated saliva and resting saliva buffering capacity at 30μL titration and the stimulated saliva and resting saliva at 40μL titration. Conclusion: Stimulated saliva is more resistant to variation in pH change during HCl titration than resting saliva. Stimulated saliva sampling is a good method to determine buffering capacity during a comprehensive oral health assessment.

This study compared the dentin bond strength of a self-etching primer/adhesive system with dentin surface pH with or without bleaching and observed the morphological changes in bleached dentin treated with a self-etching primer. Dentin disks were prepared from the coronal-labial region of 32 human anterior teeth. The pulpal surfaces of the dentin disks were polished with 600-grit SiC paper under running water. The dentin surfaces on all specimens were bleached with a mixture of 30% hydrogen peroxide and sodium perborate in 100% humidity at 37 degrees C for one week. The bleaching agent was then rinsed off with water for 5, 15 or 30 seconds. All specimens were stored in water at 37 degrees C. Half of the five-second rinsing specimens were stored in water for an additional week. Dentin surface pH with or without bleaching was examined using a pH-imaging microscope (SCHEM-100). A self-etching primer/adhesive system (Clearfil SE Bond) was applied to bleached or unbleached dentin according to the manufacturer's instructions. After 24-hour water storage, the bonded specimens were prepared for microtensile testing. Microtensile bond strength (microTBS) to dentin was measured using a universal-testing machine (EZ test, Shimadzu, Japan) at a crosshead speed of 1.0 mm/minute. Data were analyzed by one-way ANOVA and Scheffe's test (alpha=0.05). The pH values of the dentin surfaces of the 5 and 15 second rinsing groups were significantly higher than the control group (p0.05), while the 30-second rinsing and one-week water storage groups had similar surface pH values to the control group (p0.05). The microTBS of 5, 15 and 30 second rinsing specimens after bleaching were significantly lower than the control specimens (p0.05). However, after one-week of water storage, the microTBS returned to the control group. The application of a bleaching agent increased the pH value of the dentin surface and decreased the bond strength of the self-etching primer/adhesive system. One-week water storage after bleaching recovered the surface pH and the microTBS to dentin.

A pH-imaging microscope was tested on carious teeth to examine the acid-base characteristics of active and arrested carious dentinal lesions and compared with an assessment of mineral loss in carious affected lesions using an x-ray analytical microscope. Extracted human molars, 22 active and 83 arrested carious teeth, were sliced vertically to maximize the presence of visible carious lesions. The pH change on the dentin surface was measured with a pH-imaging microscope, and the mineral loss was measured with an x-ray analytical microscope. The pH value of intact dentin and active and arrested carious dentinal lesions showed 7.0 (n=105), 5.8 (n=22) and 6.6 (n=83), respectively (analyzed by Kruskal-Wallis). The mineral loss was distinguishable in active dentinal lesions (4.92 times as much as intact dentin), while arrested lesions showed a slight mineral loss (2.19 times as much as intact dentin). The changes in pH value and mineral loss were significantly correlated (Pearson's correlation coefficients r=-0.8024) in active carious dentin lesions and weakly correlated (r=-0.1480) in arrested carious dentin lesions. Changes in tooth substance with the progression of the active carious process were reflected in a reduction in pH value and an increase in the amount of mineral loss.

Objectives . This study was to examine the effect of artificial saliva contamination on pH change of the dentin surface and the micro-shear bond strength (MSBS) of the two bonding systems to contaminated dentin. Methods . Fifty-six human dentin disks were tested with two resin bonding systems: a self-etching primer system, Clearfil SE Bond (Kuraray Medical Inc., Tokyo, Japan), and a one-bottle adhesive system, Single Bond (3M-ESPE, St. Paul, MN). Dentin surfaces were conditioned with the self-etching primer (primer) or phosphoric acid (etchant) and divided into four groups: conditioning without contamination (conditioning), contamination with artificial saliva (contamination), re-conditioning the contaminated dentin (re-conditioning), water-rinsing the contaminated dentin and re-conditioning (rinsing and re-conditioning). The pH change on the dentin surface was measured using a pH-imaging microscope (SCHEM-100, Horiba Ltd, Kyoto, Japan) to estimate the acid–base characteristics of the conditioned and contaminated dentin surface. The MSBS to the dentin was examined after storage in distilled water at 37 °C for 1 week. Results . The pH of intact dentin surfaces was 6.9. Conditioning with the primer and etchant decreased the pH to 5.4 and 5.9, respectively. Saliva contamination increased the pH slightly, and re-conditioning decreased the pH again. The MSBS of the two bonding systems decreased after contamination. Re-priming restored the MSBS to control values, while re-etching did not. Rinsing and re-priming produced a reduction in MSBS, and rinsing and re-etching did not increase the MSBS. Significance . The conditioning and saliva contamination changed the pH value of dentin surface. The MSBS decreased after contamination; however, re-priming with SE Bond primer was an adequate treatment to restore the bond strength.