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Introduction: Saliva secretion is significantly lower in patients with mild reflux esophagitis than in healthy controls. A previous study on healthy controls showed that stimulated saliva secretion was lower in females than in males. Saliva secretion may be lower in female patients with mild reflux esophagitis than in male patients. Therefore, the present study investigated sex differences in saliva secretion in patients with mild reflux esophagitis. Methods: Twenty-five male patients with mild reflux esophagitis, 25 male healthy controls, 24 female patients with mild reflux esophagitis, and 24 female healthy controls were recruited for this case-control study. Saliva secretion was assessed as follows: each patient chewed sugar-free gum for 3 minutes prior to endoscopy, and the volume and pH of saliva before and after acid loading as an index of the acid-buffering capacity were measured. Results: No significant differences were observed in the amount of stimulated saliva secretion, salivary pH, or the acid-buffering capacity between male patients with mild reflux esophagitis and healthy controls. No significant differences were noted in salivary pH between female patients with mild reflux esophagitis and healthy controls; however, the amount of stimulated saliva secretion was significantly lower (p = 0.0023) in the former (2.5 [1.9–4.1]) than in the latter (4.6 [3.2–6.6]), while the acid-buffering capacity was slightly lower (p = 0.0578) in the former (5.9 [5.7–6.2]) than in the latter (6.2 [6.0–6.5]). Conclusion: The amount of stimulated saliva secretion was significantly lower in female patients with mild reflux esophagitis than in female healthy controls. This reduction in saliva secretion may affect the pathophysiology of mild reflux esophagitis in females.

Introduction: The secretion of saliva, which is triggered by acid reflux into the esophagus via the esophagosalivary reflex, plays a crucial role in the defensive mechanisms of the esophagus. The volume of saliva secreted in patients with gastroesophageal reflux disease (GERD) is reduced. However, the effects of proton pump inhibitors (PPI) on the secretion of saliva have rarely been reported. Therefore, the present study investigated changes in the volume and pH of saliva after the cessation of PPI. Materials and Methods: We retrospectively reviewed the records of consecutive patients previously diagnosed with mild reflux esophagitis (RE) or non-erosive reflux disease (NERD) controlled with PPI (including vonoprazan) who performed the salivary secretion test before and after a 2-week cessation of PPI. The volume, pH, and pH after acid loading (buffering capacity) of saliva were compared before and after the cessation of PPI. Results: Thirty-two patients (25 NERD, 7 mild RE) were included. The second saliva test was performed a median interval of 14 months [12.0–15.3] after the first test. No significant differences were observed in the volume of saliva secreted before and after the cessation of PPI (before 4.0 mL [2.7–6.0] vs. after 4.0 mL [2.3–5.9], p = 0.894). No significant differences were noted in pH or changes in pH after acid loading before and after the cessation of PPI (pH: before 7.1 ± 0.24 vs. after 7.0 ± 0.24, p = 0.1. Delta pH after acid loading: before 1.0 [0.8–1.2] vs. after 1.0 [0.8–1.2], p = 0.844). Conclusion: The cessation of PPI did not appear to affect the volume, pH, or buffering capacity of saliva in patients with PPI-responsive mild RE and NERD.

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.

Sex differences in salivary secretion have been reported among healthy subjects. In the present study, salivary secretion and salivary epidermal growth factor (EGF) concentrations were investigated in mild reflux esophagitis patients, non-erosive reflux disease (NERD) patients, and healthy controls by matching the sex ratio.Thirty-three (male:female = 11:22) patients with NERD, 33 (11:22) with mild reflux esophagitis, and 33 (11:22) healthy controls were recruited for this case-control study. Salivary secretion was assessed as follows: each patient chewed sugar-free gum for 3 min prior to endoscopy, and the amount of saliva secretion, salivary pH, and salivary pH after acid loading as an index of the acid-buffering capacity were measured. Salivary EGF concentrations were measured by ELISA.No significant differences were observed in the amount of saliva secretion, salivary pH, or the acid-buffering capacity between the mild reflux esophagitis and NERD groups. However, the amount of saliva secretion and the acid-buffering capacity in the mild reflux esophagitis group and the amount of saliva secretion, salivary pH, and the acid-buffering capacity in the NERD group were significantly lower than those in the healthy control group. No significant differences were noted in salivary EGF concentrations between the mild reflux esophagitis and NERD groups.After matching the sex ratio, the saliva secretion was significantly lower in patients with mild reflux esophagitis and NERD than in healthy controls. However, no significant differences were observed in the amount of saliva secretion or salivary EGF concentrations between both groups.

Remineralization treatment, which offers the advantage of being non-invasive, is increasingly being used as a minimal intervention treatment in managing incipient enamel caries. The aim of this review was to develop EBM guideline for optimized strategies for non-invasive treatment of incipient enamel caries. Japanese Society of Conservative Dentistry (JSCD) guideline committee formulated a Guideline for treating incipient enamel caries using the GRADE system, which is the global, mainstream standard for guideline development. The committee selected the most frequent clinical questions (CQs) in treating incipient enamel caries and identified clinically important outcomes in evaluating the efficacy of treatments. Using extensive electronic and manual searches, relevant randomized controlled trials and controlled clinical trials were identified. Based on evidence profiles produced by the committee, the panel discussed the effects, benefits and disadvantages of the selected treatments, as well as their cost effectiveness and feasibility, in order to achieve a consensus in treating incipient enamel caries non-invasively. A recommendation was made for each clinical question after voting by the panel members. Based on the evidence profile and panel discussions for each CQ, the experts strongly recommended application of topical fluoride to inhibit cavitation of incipient enamel caries, and to diminish white spot lesions.

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 quantitative diagnostic method for dental caries would improve oral health, which directly affects the quality of life. Here we describe the preparation and application of Ir/IrOx pH sensors, which are used to measure the surface pH of dental caries. The pH level is used as an indicator to distinguish between active and arrested caries. After a dentist visually inspected and defined 18 extracted dentinal caries at various positions as active or arrested caries, the surface pH values of sound and caries areas were directly measured with an Ir/IrOx pH sensor with a diameter of 300 μm as a dental explorer. The average pH values of the sound root, the arrested caries, and active caries were 6.85, 6.07, and 5.30, respectively. The pH obtained with an Ir/IrOx sensor was highly correlated with the inspection results by the dentist, indicating that the types of caries were successfully categorized. This caries testing technique using a micro Ir/IrOx pH sensor provides an accurate quantitative caries evaluation and has potential in clinical diagnosis.

This study aimed to examine the anti-demineralization capacities of (a) tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA) and 950 ppm fluoride paste, (b) casein phosphopeptide amorphous calcium phosphate paste and (c) 950 ppm fluoride solution using optical coherence tomography (OCT). Enamel blocks were cut from the bovine incisors and treated using one of the above-mentioned three materials or deionized water as control (n=10). All samples were subjected to a demineralization gel for 1 h followed by a remineralization solution for 23 h. This experimental cycle was repeated for 28 days. The specimens were imaged using OCT at baseline and at four stages and measured lesion depth using image analysis software (ImageJ). Repeated measures ANOVA revealed that demineralization time, material and their interaction significantly affected the optical lesion depth (p

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.

Root caries are becoming an increasingly common clinical problem, especially as aged-society. This report is based on the clinical practice guideline which offers a practical expert review of managing root caries with the best scientific evidence and the general consensus of expert clinicians. Root caries should be managed differently from coronal caries, and a shift of its strategy from “early-detection and early-treatment” to “early-detection and long-term management” is called for. Once the restorative treatment is chosen, it is often more advantageous to use glass-ionomer than resin composite. In addition, as we face a super-aged society now, in today’s dentistry setting, silver diammine fluoride (SDF) with high demineralization inhibitory effect is being re-evaluated as the “rescue material” (material for emergency cases) for root caries.

White spot lesions (WSL) are early non-cavitated carious lesions where the subsurface mineral loss has produced changes in the optical properties of the enamel. These lesions are visibly detectable as the loss of translucency results in a white appearance of the enamel surface. WSL can be arrested or reversed if the cariogenic challenge is sufficiently controlled or therapeutic agents are applied to promote enamel remineralization. Sugar-free chewing gum has been shown to promote the remineralization of enamel subsurface lesions in situ. Recently, manufacturers have been adding bioavailable calcium and fluoride in various forms to enhance anticariogenic and remineralization potential. This review describes the use of chewing gum which includes bioavailable agents for remineralization of WSL. Chewing gum is a noninvasive clinical approach for WSL remineralization, but further clinical studies are needed. Providing evidence on the effectiveness of these new noninvasive treatment approaches using technologies such as optical coherence tomography remains a priority in dental research.

Diagnosis of dental caries is one of the most basic skills for oral healthcare professionals; however, the detection methods are based on visually diagnosis, such as inspection, palpation, and X-ray imaging. Therefore, quantitative and objective diagnostic technique is needed [1] . The aim of this study is fabrication and evaluation of Iridium/Iridium Oxide (Ir/IrOx) pH sensor for quantitative diagnosis of dental caries. The potentiometric response to pH showed -57.4 mV/pH in evaluated pH range from 4 to 8, which demonstrated that our electrode possesses the excellent proton sensitivity (Nernst slope; -59.2 mV/pH). Based on the evaluation results of dental caries, we confirmed the possibility for quantitative diagnosis of dental caries using Ir/IrOx electrode based on the pH as an index.

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 (p 0.05). Relative hardness was statistically higher after intraoral exposure, but no differences existed among any intraoral exposure periods (p>0.05).

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.

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 (p

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).

Background: The aim of this study was to establish a new in vitro model for biofilm induced secondary caries studies using an oral biofilm reactor. Methods: An approximately 2 × 3 × 2 mm3 sized dentino-enamel Class I cavity was prepared in the middle of a square-shaped specimen from the mid-labial portion of bovine incisors. The cavities were partially filled with either Clearfil AP-X with SE-Bond or Clearfil AP-X without any bond. Artificial biofilms were then formed on the resin composite filled surfaces using three species of oral bacteria in an oral biofilm reactor for 20 hours followed by 7- or 30-day incubation periods. Results: The lesions were clearly visible on fluorescence microscopy and by scanning electron microscopy in the enamel at the interface of resin restorations in all samples. The data from image analysis showed that the lesion size was largest in the No-bond samples with statistically significant differences (p

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

To evaluate the pulp healing to bacterial contamination beneath a hard-setting calcium hydroxide (DY: Dycal, L.D. Caulk Co.) and a self-etching adhesive resin (2V: Clearfil Liner Bond 2V, Kuraray Medical Inc.) following dentin bridge formation. Class V cavities were prepared on 30 monkey teeth, and the pulps were exposed with a carbide bur through the cavity floor. Each exposed pulp was capped with either DY or 2V. The cavities were restored with a hybrid resin composite. The resin composite was removed at 180 days after capping, and then cavities were left open to the oral environment for 2 weeks to obtain bacteria contamination DY (BDY) and 2V (B2V; n = 10). A non-bacterial-contaminated group capped with DY was used as control. After bacterial challenges, inflammatory cell infiltration, incidence and differentiation of dentin bridges were evaluated histologically. There were significant differences in the presence of inflammatory cell infiltration among all groups (P < 0.05). No moderate or severe inflammatory reaction was found in Group DY. Group BDY showed moderate or severe inflammatory cell infiltration in 50%, and showed four necrotic specimens. Although no statistically significant difference was found in the formation and differentiation of dentin bridges among all groups, tunnel defects in dentin bridges were detected in 70% (DY), 80% (BDY), and 50% (B2V). Group B2V showed a significantly lower presence of inflammatory cell infiltration than Group BDY (P < 0.05). Bonding agent is supposed to seal the exposure site, and the remaining bonding agent on the cavities was effective as the barrier in the dentin bridges after bacterial challenges.

To evaluate the influence of brushing using toothpastes marketed under different categories on abrasion of sound and eroded enamel in vitro at nanometer scale using a white light interferometer (WLI).Enamel surface of resin-embedded bovine incisors were fine polished with diamond slurry and divided into testing area (approximately 2 mm x 4 mm) and reference area using a nail varnish. The enamel specimens were randomly assigned to 10 groups (n = 10 each); six of which were subjected to erosive challenge. The testing area in these eroded groups was exposed to 10 ml of Coca-Cola for 90 seconds and then rinsed for 10 seconds in deionized water (DW). Enamel specimens, except for those in one eroded group, were brushed by an automatic brushing machine with 120 linear motion strokes in 60 seconds under load of 250 g with/without toothpaste slurry. After the toothbrushing abrasion, each specimen was rinsed for 10 seconds with DW followed by immersion in artificial saliva for 2 hours. Toothpaste slurries were prepared containing one of the four toothpastes used and DW in a ratio of 1:2. The erosion-abrasion cycle was repeated three times. Then, the nail varnish was removed and enamel surface loss (SL) was measured by the WLI. Data were statistically analyzed by one-way ANOVA followed by Bonferroni's correction at significance level of 0.05.For eroded specimens, the mean SL values of groups not brushed and brushed with no toothpaste were not significantly different, but were significantly lower than those of whitening, anti-erosion and anti-caries toothpaste groups (P0.001). The whitening toothpaste group showed significantly higher SL than all other groups (P0.001). For sound enamel specimens, SL was not measured except for the whitening toothpaste group.

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.

Aim Acidic diffusion through bovine dentine was investigated by measuring pH changes on dentine surfaces after applying three adhesive systems. Methodology Coronal incisor bovine dentine discs, 0.5 mm thick, were prepared from dentine close to the pulp chamber. A single-bottle adhesive system-Single Bond, a self-etching primer system-Clearfil SE Bond and an ‘all-in-one’ adhesive system-AQ Bond were used. The labial dentine surfaces were conditioned as follows: Single Bond groups: (SB-1) 35% phosphoric acid etchant was applied and left in place; (SB-2) the etchant was applied for 15 s and rinsed off for 10 s; (SB-3) application of adhesive agent and light curing following step SB-2; Clearfil SE Bond groups: (SE-1) SE primer was applied for 20 s and dried; (SE-2) application of adhesive agent and light curing following step SE-1; AQ Bond groups: (AQ-1) AQ Bond adhesive was applied for 20 s and dried, applied for additional 5 s and dried again; (AQ-2) light curing following step AQ-1. The pH change on the pulpal dentine surface was measured using a pH-imaging microscope. Results All the Single Bond groups revealed a lower pH on the pulpal surface (pH 6.25, 6.59 and 6.64 for SB-1, SB-2 and SB-3, respectively) compared with intact dentine. Clearfil SE Bond and AQ Bond groups showed no significant deference in pH value from intact dentine. Conclusions Acid diffusion from phosphoric acid etching was observed when placed on 0.5 mm-thick dentine discs; however, there was only limited evidence of acid diffusion from SE primer and AQ Bond.

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.

Aim To examine the changes in pH of luting cements and acid diffusion of luting cements through bovine dentine using a pH-imaging microscope (SCHEM-100; Horiba Ltd, Kyoto, Japan). Methodology The pH of the surface of three conventional luting cements, glass-ionomer, zinc phosphate and zinc polycarboxylate was measured with SCHEM-100 for 1 month. The acid diffusion from the three luting cements through bovine dentine was investigated by measuring pH changes during the application of each luting cement on the bovine dentine surface. Coronal bovine dentine disks were prepared to thicknesses of 0.50 and 0.25 mm. Each luting cement was placed on the labial dentine surface, and the pH change of the pulpal surface was observed every 3 min for 30 min with SCHEM-100. Results Glass-ionomer showed the lowest pH values for longer times. Neutralization proceeded furthest in zinc polycarboxylate. The 0.5-mm-thick dentine disks showed no pH change on the pulpal side with all the three cements. The 0.25-mm-thick disks revealed evidence of acid diffusion on the pulpal side of the cemented dentine and significantly lower pH when cemented with glass-ionomer and zinc phosphate than with zinc polycarboxylates. Conclusions This study demonstrated that glass-ionomer exhibited a lower setting pH than zinc phosphate and zinc polycarboxylate, and acid diffusions from glass-ionomer and zinc phosphate cements were observed when placed on 0.25-mm-thick dentine disks.

AIM: To assess the location, arrangement and possible function of interodontoblastic collagen fibres in association with calcium hydroxide-induced hard tissue bridges by using light and transmission electron microscopy techniques and immunohistochemical staining localization. METHODOLOGY: Prior to the study, an animal use protocol form was reviewed and approved by the Screening Committee for Animal Research of the Tokyo Medical and Dental University. Exposed monkey pulps were capped with a hard-set calcium hydroxide and histopathologically evaluated at 3, 14, 21, 30 and 90 days, using light microscopy with silver staining and transmission electron microscopy to differentiate structural features of interodontoblastic collagen fibres. In addition, an attempt was made to identify and to differentiate between several types of collagen and fibronectin using immunohistochemical localization techniques. RESULTS: At 14 days, interodontoblastic collagen fibres were observed extending from the original dentine, passing through the odontoblasts, and consisted of two portions: a thick fibril and a thin fibril. At 21 days, interodontoblastic collagen fibres were seen penetrating into the predentine and becoming incorporated into the mineralized dentine. At 30 days, interodontoblastic collagen fibres reached the cell process. Although interodontoblastic collagen fibres were no longer observed near the odontoblastoid cells at the area of the newly formed tubular dentine, interodontoblastic collagen fibres were observed embedded within the primary formed dentine bridge. Immunohistochemical staining demonstrated type I collagen and fibronectin within the interodontoblastic collagen fibres. CONCLUSIONS: Interodontoblastic collagen fibres were routinely detected throughout early dentine bridges. Interodontoblastic collagen fibres are thought to be important for initial dentine bridging to induce and support a dentinogenesis framework.

Objectives. Following tooth pulp exposure, pulpal repair is accomplished by dentine bridge secretion by odontoblast-like cells. However, little information is available about the hierarchy of variables, which influence odontoblast-like cell numbers. The purpose of this study was to examine correlations between pulp capping events and odontoblast-like cell numbers. Methods. Two hundered and fifty standardised pulp exposed cavities were prepared in non-human primate teeth according to ISO usage guidelines. Exposed pulps were capped with Calcium hydroxide [Ca(OH)2], and multi-step and self-etching primer composite resins. Teeth were collected from 3 to 60-days to observe pulp reactions. Statistical analysis was evaluated using analysis of variance. Results. The hierarchy of variables correlated to odontoblast-like cells were the dentine bridge area (P=0.0001), time since pulp exposure (P=0.0001), odontoblast numbers opposite the exposure site (P=0.0002), and pulp capping materials (P=0.0313). Other pulp capping variables were found to be less likely to be correlated with odontoblast-like cell numbers. Conclusions. The area of dentine bridge formation is directly related to the numbers of odontoblast-like cells, cell activity is time dependent, and the cell numbers are much lower than original odontoblast cells. The time-lag between the appearance of odontoblast-like cells at the site of pulp exposure, and the limited numbers of these cells, explain why pulpal repair is difficult to achieve successfully following pulp exposure.

Objectives: This study was conducted to evaluate the tensile bond durability of two different types of 4-META containing resin cements over a period of 3 years. Methods: Ten bovine dentin specimens were tested for tensile bond strengths with each of the following materials: Super Bond C&B: unfilled methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) resin cement, MASA Bond (experimental material): filled dimethacrylate resin cement at 1 day, 6 months, 1 and 3 years. The mean bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test (P0.05) during the experimental periods, the 1-day bond strengths were significantly greater than those at the other experimental periods except for 6 months (P

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.

This study was conducted to evaluate the bond durability of three resin cements bonded to bovine dentine over a period of 3 years.Ten bovine dentine specimens were tested for shear bond strengths with each of the following materials: Panavia 21, BISTITE resin cement, and MASA Bond (experimental resin cement) at 1 day, 6 months, 1 and 3 years after cementation of a composite rod. All specimens were stressed in shear at a crosshead speed of 1mm min(-1) until failure. The means of the bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test (P0.05). The mode of failure was classified after fracture of the bonds by SEM observation. Results for the mode of fracture were analyzed using the Mann-Whitney U-test.The shear bond strengths (MPa+/-SD) for different times (1 day, 6 months, 1 and 3 years) were: Panavia 21 (15.2+/-3.6, 9.3+/-3.2, 8.5+/-2.1, 6.8+/-2.4), BISTITE (15.6+/-2.8, 11.0+/-1.4, 10.4+/-2.2, 9.0+/-2.7) and MASA Bond (29.6+/-9.5, 17.5+/-4.6, 19.6+/-4.5, 16.1+/-5.4). Panavia 21 and BISTITE strengths were significantly lower (P0.05) at all times compared with MASA Bond, and 1 day strengths for all three materials were significantly higher (P0.05) than 3 year strengths. Regarding the fracture modes after bond testing, there were statistical differences between the 1 day and the 1 year results for all cements (P0.05). Although no Panavia 21 specimen showed complete cohesive failure in the demineralized dentine during the experiment, several BISTITE and MASA Bond specimens showed cohesive fracture in the demineralized dentine. For BISTITE, partially or complete demineralized dentine cohesive failures increased over time.The type of resin cement seemed to have an influence on the long-term durability of bonding to dentine.

Objectives: The aim of this in vivo study was to investigate the biocompatibility and microtensile bond strength of a one-application resin bonding system. Methods: Class V cavities were prepared on the facial surfaces of 36 intact monkey teeth, and the cavities were restored with an experimental one-application resin bonding system (TOF-1; Tokuyama Corp., Tokuyama, Japan) and a hybrid resin composite (PALFIQUE ESTELITE; Tokuyama Corp., Tokuyama, Japan). Histopathological changes of the restored teeth were evaluated at 3, 30 and 90 days after operation (N=10). Microtensile bond tests were performed at 3 and 90 days after operation (N=10). Results: Only two of 30 pulps showed a slight inflammatory cell infiltration. There were no statistically significant differences in the incidence of slight inflammatory cell infiltration among time periods. Bacterial penetration along the cavity walls could not be detected in any specimen. The mean microtensile bond strength at 3 days after operation was 20.6 MPa, and that at 90 days was 14.9 MPa. Differences in bond strengths between the 3 day specimen and the 90 day specimen were statistically significant (p Conclusions: The one-application resin bonding system exhibited acceptable biologic compatibility to the monkey pulp. Although there were statistically significant differences in bond strengths between the 3 day specimen and the 90 day specimen, this material provided a hermetic seal, eliminating bacterial microleakage.

Objective. The aim of this investigation was to assess the role of the von Korff–like fibers (VKF) during the process of dentin bridging. Study design. The monkey pulps, exposed to a hard-set calcium hydroxide, were evaluated at 3, 7, 14, 21, 30, 90, and 180 days. Results. At 21 days, longitudinal and transverse collagen fibrils were organized as lamellar structures in close proximity to and subjacent to the newly formed predentin. VKF bundles were present between newly formed odontoblastoid cells. The VKF were bundles of thin collagen fibrils inserted into the predentin, which consisted of thick collagen fibrils. At 30 days, the exposure site was completely occluded with a new predentin matrix; lamellar structures and VKF were no longer present. Conclusions. The VKF may play a role in the connective tissue attachment to the dentin bridge, early in its formation. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;89:224-30)