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Vital pulp treatment (VPT) is a therapeutic strategy aimed at conservatively managing deep carious lesions and the exposed pulp. VPT has recently expanded through the use of hydraulic-calcium-silicate cement (HCSC), cone-beam CT, and dental operating microscopy (DOM), as well as an improved understanding of pulpal repair mechanisms. Consensus documents have concluded that non-selective removal of caries is not necessary in the absence of clinical symptoms, as partial or non-selective caries removal techniques reduce the likelihood of pulp exposure. Alternatively, others suggest that leaving carious tissue may help sustain pulpal inflammation and lead to failure of VPT. The presence of a purulent discharge from the exposed pulp is considered indicative of an irreversible damage and a need for pulpectomy. This report documents the successful VPT in a symptomatic molar with deep caries that exhibited purulent discharge from the pulp after exposure. A female patient presented with spontaneous pain in the maxillary left second molar. One year before, she had received a cast-metal restoration over a resin-based-composite (RBC) restoration. The tooth had been largely asymptomatic since; however, after experiencing spontaneous pain, she consulted the hospital clinic. Radiographs indicated that the restoration was not deep with visible dentin between the restoration and the pulp. Pulp sensibility tests yielded a positive response. There was no pain on percussion and no periodontal problems. Removal of the restoration and carious dentin using a DOM resulted in a pulpal exposure with purulent discharge and bleeding. A partial pulpotomy using HCSC was performed. Six months later, the clinical symptoms had completely resolved; however, due to concerns of partial necrosis, the patient was re-assessed. DOM examination revealed an incomplete hard-tissue barrier; moreover, there were also signs of residual tissue with inflammation. As a result, the defected area was enlarged, the pulp tissue debrided, and the HCSC reapplied. After review at 1 year, the tooth remains symptomless, with no apical radiolucency. Notably, this report visually illustrates that exposed pulp tissue containing limited region pus can maintain vitality after VPT. This finding raises two questions: (1) whether leaving infected dentin in situ and avoiding visualization of the pulp exposure is appropriate; and (2) whether the presence of purulent tissue in the pulp warrants a pulpectomy.

Aim: Fluoride is widely used in dentistry for its caries prevention. To reduce dental caries, the optimal fluoride concentration of public water supplies in the United States is 0.7 ppm. However, excessive systemic fluoride consumption can lead to dental/enamel fluorosis. Numerous studies have explored the effects of fluoride on enamel and enamel-forming cells. However, research on systemic fluoride's impact on dentine is limited, particularly the effect of fluoride on the structure of the dentine-pulp complex. Therefore, this study aimed to identify how excessive fluoride affects dentine microstructure using an experimental mouse model., Methodology: C57BL6/J male mice (6-9 weeks old) were randomized into four groups (Fluoride at 0, 50, 100, or 125 ppm in drinking water) (n = 4/group). Mice were provided water ad libitum for 6 weeks along with fluoride-free food. Thereafter, mandibular incisors were analysed. Enamel phenotypes were evaluated using light microscopy and quantitative light-induced fluorescence (QLF) to measure fluorosis levels. Dentine morphology was evaluated using micro-CT, scanning electron microscopy (SEM), SEM-EDX (energy-dispersive X-ray), microhardness test and histological imaging. Data were analysed using one-way ANOVA with Dunnett's multiple comparisons as a post hoc test and the Kruskal-Wallis test with Dunn's multiple comparisons post hoc test (p < .05)., Results: Mice treated with fluoride at 50-125 ppm developed enamel hypoplasia in their erupting incisors and micro-CT imaging revealed that fluoride 125 ppm caused external resorption of the growing incisor. Dentine mineral density, dentine volume decreased compared with the 0 ppm control, while pulp volume increased compared with the 0 ppm control group. SEM showed wider predentine layer and abnormalities in calcified matrix vesicles derived from odontoblasts in fluoride 100 and 125 ppm groups. Vickers microhardness of dentine significantly decreased in the high-dose group. Fluoride-induced dentine hypoplasia in a dose-dependent manner. Histological evaluation showed excessive fluoride 125 ppm induced micro abscess formation and inflammatory cell infiltration. Fluoride induced dentine dysplasia with a dentine microstructure resembling hypophosphatasia., Conclusions: High doses of systemic fluoride can cause dentine dysplasia. Both three-dimensional and microstructural analyses showed the structural, chemical and mechanical changes in the dentine and the mineralized tissue components, along with external resorption and pulp inflammation., (© 2024 British Endodontic Society. Published by John Wiley & Sons Ltd.)

Objectives: The aim of this study was to quantitatively and comprehensively investigate the combined effects of arginine and fluoride on the suppression of pathogenicity using an in situ biofilm model and next-generation sequencing (NGS)., Methods: Using the in situ model, dental biofilms were formed and the viable bacterial counts and arginine activity in the arginine- and fluoride-containing dentifrice and control groups were measured. We also compared their effects on the bacterial microbiota and predictive functional factors in the control, arginine (arg), and arginine + fluoride (argF) groups using NGS analysis., Results: Compared to the control treatment, the use of 8 % arginine and 1450 ppm fluoride toothpaste resulted in significantly high oral NH 4 + concentrations without affecting the number of viable bacteria (P < 0.05). NGS analysis revealed that the oral microbiota of the control, arg, and argF groups were significantly different. Heat map analysis of the predicted functional factors revealed that the arg group had different properties from the other groups and activated specific substrate metabolic pathways; contrastingly, argF treatment inhibited the activity of these pathways and prevented an increase in the abundance of bacterial genera that utilize substrates such as sucrose, suggesting the synergistic effect of arginine and fluoride., Conclusions: This study indicates that the combination of arginine and fluoride has a synergistic effect on the bacterial microbiota and pathogenicity of dental biofilms compared with arginine alone., Clinical Significance: Our findings suggest that the combination of arginine and fluoride could be used as an effective prebiotic and may inhibit the growth of bacteria associated with dental diseases., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier Ltd.)

Excessive fluoride ingestion during tooth development can cause dental fluorosis. Previously, we reported that fluoride activates histone acetyltransferase (HAT) to acetylate p53, promoting fluoride toxicity in mouse ameloblast-like LS8 cells. However, the roles of HAT and histone acetylation status in fluoride-mediated gene expression remain unidentified. Here, we demonstrate that fluoride-mediated histone modification causes gene expression alterations in LS8 cells. LS8 cells were treated with or without fluoride followed by ChIP-Seq analysis of H3K27ac. Genes were identified by differential H3K27ac peaks within ±1 kb from transcription start sites. The levels of mRNA of identified genes were assessed using rea-time PCR (qPCR). Fluoride increased H3K27ac peaks associated with Bax , p21 , and Mdm2 genes and upregulated their mRNA levels. Fluoride decreased H3K27ac peaks and p53 , Bad , and Bcl2 had suppressed transcription. HAT inhibitors (Anacardic acid or MG149) suppressed fluoride-induced mRNA of p21 and Mdm2 , while fluoride and the histone deacetylase (HDAC) inhibitor sodium butyrate increased Bad and Bcl2 expression above that of fluoride treatment alone. To our knowledge, this is the first study that demonstrates epigenetic regulation via fluoride treatment via H3 acetylation. Further investigation is required to elucidate epigenetic mechanisms of fluoride toxicity in enamel development.

Introduction: A 65-year-old man had nonsurgical retreatment using an iodoform and calcium hydroxide paste in a maxillary left canine with persistent apical periodontitis. An apical mineralized barrier (AMB) was observed 3-months postoperatively. Unfortunately, the tooth was extracted due to a cementum tear. This provided an opportunity to analyze the AMB histologically, as there is a lack of previous reports on its microstructure., Methods: After extraction and removal of the granulation tissue from the root surface, the canine was processed, and observed using micro-computed tomography (μCT) and light microscopy. Thereafter, the specimen was resin-embedded specimen was evaluated by scanning electron microscopy, micro-X-ray fluorescence spectroscopy and Raman spectroscopy to understand the mechanism and nature of the AMB formation during apical healing., Results: Nonsurgical retreatment was clinically successful based on the absence of clinical symptoms of apical periodontitis and the radiographic presence of an AMB. The AMB was opaque and could be readily differentiated from dentin under a light microscope. Micro-computed tomography analysis revealed that the AMB had the same mineral density as dentin. Scanning electron microscopy revealed that the AMB had two distinct layers based on the size of the calcified particles. Elemental mapping using micro-X-ray fluorescence spectroscopy showed that the localization of calcium and phosphorus differed between AMB and other areas of biomineralization. Raman spectral mapping revealed that the surface layer of the AMB consisted of collagen, calcium carbonate, and hydroxyapatite., Conclusions: This study explored new analytical methods for elucidating the apical wound-healing process and the nature of the mineralized repair. The findings provided detailed information on the AMB highlighting a bilaminar structure with high calcium components higher on the inside and a brightness similar to cementum not dentin and the presence of hydroxyapatite., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Treatment of large external cervical resorption (ECR) lesions may be compromised, rendering the tooth unrestorable. Intentional replantation is a potential treatment option depending on the site and extent of ECR. We present a case of a large ECR successfully managed with intentional replantation with rotation of the tooth. The female patient consulted the hospital clinic, with an extensive palatal ECR on the maxillary lateral incisor. Routine planar radiographs and cone-beam computed tomography demonstrated a larger palatal than the ECR lesion (Heithersay Class III and Patel's Class 2Bp) not amenable to nonsurgical treatment. Intentional replantation after short-term extrusion was planned. The defect was restored, then a palatal ferrule was achieved by rotating the tooth by 180°. At the 18-month follow-up, the periradicular and periodontal tissues remained healthy, and no other symptoms were reported. In conclusion, this successful video-illustrated clinical case highlights the benefits of intentional replantation in saving teeth with advanced ECR., Competing Interests: The author(s) declare that they have no conflicts of interest., (Copyright © 2023 Motoki Okamoto et al.)

Gutta-percha points and root canal sealers have been used for decades in endodontics for root canal obturation. With techniques such as single cone methods, the amount of sealer is larger, making their properties more critical. However, relatively few reports have comprehensively evaluated their biological effects. To this end, we evaluated three types of sealers, zinc oxide-fatty acid-, bio-glass- and methacrylate resin-containing sealers were considered. Their biological effects were evaluated using a rat subcutaneous implantation model. Each sealer was loaded inside a Teflon tube and implanted subcutaneously in the backs of rats. Inflammatory cells were observed around all samples 7 days after implantation and reduced after 28 days. Our results revealed that all samples were in contact with the subcutaneous tissue surrounding the sealer. Additionally, Ca and P accumulation was observed in only the bio-glass-containing sealer. Furthermore, each of the three sealers exhibited unique immune and inflammatory modulatory effects. In particular, bio-glass and methacrylate resin sealers were found to induce variable gene expression in adjacent subcutaneous tissues related to angiogenesis, wound healing, muscle tissue, and surrounding subcutaneous tissue. These results may help to understand the biological impacts of root canal sealers on surrounding biological tissues, guiding future research and comparisons with new generations of materials.

Silver diamine fluoride (SDF) has been long studied in laboratories, and its clinical effectiveness in the treatment and prevention of root caries has been reported. In the present study, we assessed the microbiological effects of SDF on dental biofilms grown on demineralized dentin in situ. Specifically, demineralized bovine root dentin slabs used as biofilm substrates were treated with 38% SDF, and the biofilms formed after this treatment were analyzed via real-time PCR, DEAD/LIVE cell staining, and SEM. Next, the viable cell count was determined, and microbial profiles were compared using 16S rRNA gene sequencing. Untreated slabs were used as controls. We observed significant decreases in viable cell counts (p < 0.05), number of biofilm-forming cells (p < 0.01), biofilm thickness (p < 0.01), and high proportion of dead cells with SDF treatment (p < 0.01). The microcolonies in the SDF-treated biofilms showed less complexity, and only a limited number of genera were differentially abundant between the groups. Microbial diversity index comparisons showed no significant differences between the groups with respect to treatments days (p = 0.362). Thus, SDF negatively influenced dental biofilm growth on demineralized root dentin in situ; however, its antimicrobial action did not target a specific oral taxon., (© 2022. The Author(s).)

Dysbiosis of the oral microbiome is associated with diseases such as periodontitis and dental caries. Because the bacterial counts in saliva increase markedly during sleep, it is broadly accepted that the mouth should be cleaned before sleep to help prevent these diseases. However, this practice does not consider oral biofilms, including the dental biofilm. This study aimed to investigate sleep-related changes in the microbiome of oral biofilms by using 16S rRNA gene sequence analysis. Two experimental schedules-post-sleep and pre-sleep biofilm collection-were applied to 10 healthy subjects. Subjects had their teeth and oral mucosa professionally cleaned 7 days and 24 h before sample collection. Samples were collected from several locations in the oral cavity: the buccal mucosa, hard palate, tongue dorsum, gingival mucosa, tooth surface, and saliva. Prevotella and Corynebacterium had higher relative abundance on awakening than before sleep in all locations of the oral cavity, whereas fluctuations in Rothia levels differed depending on location. The microbiome in different locations in the oral cavity is affected by sleep, and changes in the microbiome composition depend on characteristics of the surfaces on which oral biofilms form., Competing Interests: The authors have declared that no competing interests exist.

Oral biofilms are associated with caries, periodontal diseases, and systemic diseases. Generally, antimicrobial therapy is used as the first line of treatment for infectious diseases; however, bacteria in biofilms eventually develop antibiotic resistance. This study aimed to apply our in situ biofilm model to verify whether an arginine preparation is useful for plaque control. Ten healthy subjects who did not show signs of caries, gingivitis, or periodontitis were recruited. The dental biofilms from the subjects were obtained using our oral device before and after gargling with arginine solution for 4 weeks. We found that 8% arginine solution significantly increased the concentration of ammonium ions (NH 4 + ) in vitro and in vivo in saliva ( p < 0.05) and decreased the proportions of the genera Atopobium and Catonella in vivo. However, the viable count was unaffected by the mouthwash. Further, oral populations of the genera Streptococcus and Neisseria tended to increase with the use of arginine. Therefore, we concluded that using an 8% arginine solution decreased the NH 4 + concentration in the oral cavity without affecting the number of viable bacteria, and that the diversity of oral bacterial flora changed. We suggest that arginine might help prevent mature biofilm formation.

Dental biofilm present on the tooth surface is associated with oral diseases, such as dental caries and periodontal disease. Because bacterial numbers rapidly increase in saliva during sleep, oral care before sleeping is recommended for the prevention of chronic oral diseases. However, temporal circadian changes in the quantity and quality of dental biofilms are poorly understood. This study aimed to investigate the impacts of sleeping on dental biofilm amounts and compositions by using an in situ model. The use of this in situ model enabled us to investigate dental biofilm formed in the oral cavity and to perform a quantitative analysis. Subjects began wearing oral splints in the morning or before sleeping, and biofilm samples were collected at 8, 16, and 24 h after the subjects began wearing oral splints; these samples were then used in various experiments. No significant changes in the numbers of biofilm-forming bacteria were caused by sleep. However, the relative abundances of genera related to periodontitis (i.e., Fusobacterium and Prevotella) increased after awakening. In conclusion, the numbers of biofilm-forming bacteria were not affected by sleep, and the abundances of obligate anaerobes increased after sleep. This research may aid in defining efficacious preventive oral care.

Background: Bacterial biofilms that develop on root surfaces outside apical foramens have been found to be associated with refractory periapical periodontitis. However, several other factors cause endodontic failures apart from extraradicular biofilms. The aim of this study was to identify the factors causing endodontic failures in general practices in Japan., Methods: Patients diagnosed as having refractory periapical periodontitis by general practitioners and who requested endodontic treatment at Osaka University Dental Hospital were selected by checking medical records from April 2009 to March 2013. Factors causing endodontic failures were identified., Results: A total of 103 teeth were selected, and 76 teeth completed root-canal treatment. Tooth extractions were required for 18 teeth after or without endodontic treatment. Six teeth required apicoectomy after endodontic treatment. One tooth needed hemisection. One tooth needed intentional replantation. One tooth needed adhesion and replantation. The main causes of treatment failure were open apices (24 teeth), perforation (18 teeth), and root fracture (13 teeth). In six teeth with open apices that required apicoectomy or extraction, extraradicular biofilms may have been related to endodontic failure., Conclusions: Most endodontic cases diagnosed with refractory periapical periodontitis by general practitioners were compromised by any other factors rather than extraradicular biofilms.

Aims: To clarify differences in objective activity levels between children with attention-deficit/hyperactivity disorder (ADHD) and those with pervasive developmental disorders (PDD) and hyperactivity., Method: Eighteen boys with combined type ADHD, 10 boys with PDD with hyperactivity, and 18 control boys wore actigraphs for 1 week while attending elementary school. In addition to the average activity level, the standard deviation in the activity levels were compared for two continuous situations: (i) in-seat classes, in which the participants were expected to sit in their own seats and learn quietly; and (ii) free recess periods following the in-seat classes., Results: All the groups were affected by the situational shift, the average activity level of each the groups was higher and the standard deviation was smaller than those during the in-seat classes. The boys with ADHD exhibited a still smaller standard deviation than the controls and the boys with PDD and hyperactivity during the free recess period; no difference between the controls and the boys with PDD was seen. The boys with PDD exhibited a significantly lower average activity level than the other groups. No differences among the groups in the average activity levels and standard deviation were seen during the in-seat classes., Conclusions: The observed objective activity levels in each group reflect the degree to which the boys are able to tolerate changes in situations. Objective measurement of activity levels may be useful to differentiate hyperactivity in children with ADHD from that in children without ADHD.

The aim of this study was to determine whether the objective activity level of children with attention deficit/hyperactivity disorder (AD/HD) is associated with situational factors in elementary school. A total of 16 children with combined-type AD/HD (13 boys, 3 girls) and 20 controls matched for age and gender participated in the study. All the participants wore the objective measurement of activity level for 1 week while attending elementary school. The average activity levels were calculated for the morning and afternoon classes. The classes were categorized into four types: (i) in-seat classes, in which the participants were expected to learn quietly while sitting in their own seats; (ii) not-in-seat classes, in which the participants were not expected to sit in their seats; (iii) physical education classes; and (iv) lunch/recess periods. During the afternoon in-seat classes, the children with AD/HD were significantly more active than the controls. However, no significant differences based on the group (children with AD/HD or controls) were observed during the other morning or afternoon classes. These findings indicate that in naturalistic settings where the effects of situational demands involving inhibition and the effect of fatigue overlapped, the children with AD/HD exhibited an activity level that was different from that exhibited by the controls. Differences in the activity levels of children with AD/HD and normal controls were identified using an objective measurement of activity level when two situational factors overlapped.