Title IgA Nephropathy and Oral Bacterial Species Related to Dental Caries and Periodontitis

A relationship between IgA nephropathy (IgAN) and bacterial infection has been suspected. As IgAN is a chronic disease, bacteria that could cause chronic infection in oral areas might be pathogenetic bacteria candidates. Oral bacterial species related to dental caries and periodontitis should be candidates because these bacteria are well known to be pathogenic in chronic dental disease. Recently, several reports have indicated that collagen-binding protein (cnm)-(+) Streptococcs mutans is relate to the incidence of IgAN and the progression of IgAN. Among periodontal bacteria, Treponema denticola, Porphyromonas gingivalis and Campylobacte rectus were found to be related to the incidence of IgAN. These bacteria can cause IgAN-like histological findings in animal models. While the connection between oral bacterial infection, such as infection with S. mutans and periodontal bacteria, and the incidence of IgAN remains unclear, these bacterial infections might cause aberrantly glycosylated IgA1 in nasopharynx-associated lymphoid tissue, which has been reported to cause IgA deposition in mesangial areas in glomeruli, probably through the alteration of microRNAs related to the expression of glycosylation enzymes. The roles of other factors related to the incidence and progression of IgA, such as genes and cigarette smoking, can also be explained from the perspective of the relationship between these factors and oral bacteria. This review summarizes the relationship between IgAN and oral bacteria, such as cnm-(+) S. mutans and periodontal bacteria.

Disruption of the adh (acetoin dehydrogenase) operon has wide-ranging effects on Streptococcus mutans growth and stress response

The agent largely responsible for initiating dental caries, Streptococcus mutans produces acetoin dehydrogenase that is encoded by the adh operon. The operon consists of the adhA and B genes (E1 dehydrogenase), adhC (E2 lipoylated transacetylase), adhD (E3 dihydrolipoamide dehydrogenase), and lplA (lipoyl ligase). Evidence is presented that AdhC interacts with SpxA2, a redox-sensitive transcription factor functioning in cell wall and oxidative stress responses. In-frame deletion mutations of adh genes conferred oxygen-dependent sensitivity to slightly alkaline pH (pH 7.2-7.6), within the range of values observed in human saliva. Growth defects were also observed when glucose or sucrose served as major carbon sources. A deletion of the adhC orthologous gene, acoC gene of Streptococcus gordonii , did not result in pH sensitivity or defective growth in glucose and sucrose. The defects observed in adh mutants were partially reversed by addition of pyruvate. Unlike most 2-oxoacid dehydrogenases, the E3 AdhD subunit bears an N-terminal lipoylation domain nearly identical to that of E2 AdhC. Changing the lipoyl domains of AdhC and AdhD by replacing the lipoate attachment residue, lysine to arginine, caused no significant reduction in pH sensitivity but the adhDK43R mutation eliminating the lipoylation site resulted in an observable growth defect in glucose medium. The adh mutations were partially suppressed by a deletion of rex , encoding an NAD + /NADH-sensing transcription factor that represses genes functioning in fermentation. spxA2 adh double mutants show synthetic growth restriction at elevated pH and upon ampicillin treatment. These results suggest a role for Adh in stress management in S. mutans . IMPORTANCE Dental caries is often initiated by Streptococcus mutans , which establishes a biofilm and a low pH environment on tooth enamel surfaces. The current study has uncovered vulnerabilities of S. mutans mutant strains that are unable to produce the enzyme complex, acetoin dehydrogenase (Adh). Such mutants are sensitive to modest increases in pH to 7.2-7.6, within the range of human saliva, while a mutant of a commensal Streptococcal species is resistant. The S. mutans adh strains are also defective in carbohydrate utilization and are hypersensitive to a cell wall-acting antibiotic. The studies suggest that Adh could be a potential target for interfering with S. mutans colonization of the oral environment.

Inhibitory Effect of Oral Thin Films (OTFs) Containing Xylitol Against Streptococcus mutans

Dental Caries is a chronic disease affecting half of the global population, causing pain and discomfort due to progressive damage to the teeth. Whilst xylitol has been studied for its effect on dental caries prevention, current practices present few limitations for its successful oral delivery, including short residence time in the mouth and poor patient compliance. Recently, oral thin films (OTFs) emerged as an alternative to delivering xylitol in the oral cavity. This research aims to develop novel OTFs containing xylitol with extended-release properties (as determined by the disintegration time) and to investigate its effect on a cariogenic bacterial strain, Streptococcus mutans. The minimum inhibitory concentration (MIC) of xylitol was determined. Employing the microdilution broth method, the antibacterial activity of the oral thin films containing xylitol for oral S. mutans was performed with simulated salivary fluid, incubated at 1, 4, and 10 h. The MIC of xylitol was found at 10%. Meanwhile, there was no significant difference in the inhibition of S. mutans (p > 0.05) between the control, OTFs (10 h), and xylitol-OTF (1 h), with the latter, demonstrated only 16.58% inhibition. Interestingly, when compared to xylitol-OTF (1 h), xylitol-OTF showed significant inhibition (p < 0.05) to S. mutans after four h (+53.24 %) and almost a complete inhibition after ten h (-92.58 %). These results suggest that the OTFs demonstrated a gradual release of xylitol and inhibited oral biofilm formation by decreasing the growth of S. mutans in a time-dependent manner. Most importantly, the study indicated the successful development of a novel xylitol-OTF with potential as an oral health biotherapeutic agent.

Future of Decellularized Dental Pulp Matrix in Regenerative Endodontics

With the advancements in tissue engineering, the repair and regeneration of oral/dental tissue are becoming possible and productive. Due to periodontal diseases, the tooth loses bone support resulting in tooth loss, but bone grafting stabilizes with new bone. It is seen that due to the progression of dental caries, pulp damage happens, and the vitality of the tooth is compromised. The current theme of dental pulp regeneration through biological and synthetic scaffolds, is becoming a potential therapy for pulp revitalization.

General and Paediatric Dentists’ Knowledge, Attitude and Practices Regarding the use of Silver Diammine Fluoride for the Management of Dental Caries: A National Survey in the Netherlands

Background: Silver Diammine Fluoride (SDF) is a topical medication used to arrest cavitated carious lesions non-invasively. The primary aim of this research was to investigate, and analyse the relationships between; knowledge, attitudes and practices (including barriers and facilitators) as they relate to SDF use for the management of dental caries by general dental practitioners (GDPs) and paediatric dentists (PDs) in the Netherlands. A secondary aim was to explore any differences between these groups.Methods: A sample of 600 Dutch GDPs (random selection from 9,777 registered) and all 57 registered PDs were invited to participate in this cross-sectional survey, consisting of four sections: 1) participant characteristics, 2) knowledge (through responses to summative questions), 3) attitudes (through agreements using 5-point Likert scale), and 4) practices, use, barriers and facilitators (through multiple choice questions). Results: Response rates were: GDPs 23% (n=140) and PDs 47% (n=27). Knowledge: out of 15 questions testing understanding of SDF, the mean correct answers were GDPs 6.7; SD 2.6 and PDs 7.4, SD 2.2 (no statistically significant differences). Mean overall attitude score showed positivity towards SDF use in both groups. Compared to GDPs, PDs were more likely to use SDF (p<0.001) and expected this to increase (p=0.03). The main barrier for users was parental acceptance (47%) and for non-users it was lack of knowledge (60%). The main facilitator for both users and non-users was gaining knowledge through courses and workshops, followed by written information leaflets about SDF for parents.Conclusions: Less than half knowledge questions about SDF were answered correctly. Despite low knowledge, attitude towards its use was positive. Practitioners believed that its use would be facilitated by professionals having more accessible information and training and by the availability of parent information leaflets. SDF was used more frequently by PDs than GDPs.

Single-Cell Transcriptomic Profiling of Human Dental Pulp in Sound and Carious Teeth: A Pilot Study

A comprehensive understanding of dental pulp cellular compositions and their molecular responses to infection are crucial for the advancement of regenerative dentistry. Here, we presented a pilot study of single-cell transcriptomic profiles of 6,810 pulpal cells isolated from a sound human maxillary third molar and three carious teeth with enamel and deep dental caries. We observed altered immune cell compositions of the dental pulp in deep, but not enamel ones. Differential expression analysis revealed up-regulation of several pro-inflammatory, anti-inflammatory, and mineralization-related genes in the immune and stromal cells of the deep dental caries. Making use of an algorithm for predicting cell-to-cell interactions from single-cell transcriptomic profiles, we showed an increase in cell-cell interactions between B cells, plasma cells and macrophages, and other cell types in deep dental caries, including those between TIMP1 (odontoblasts)—CD63 (myeloid cells), and CCL2 (macrophages)—ACKR1 (endothelial cells). Collectively, our work highlighted the single-cell level gene regulations and intercellular interactions in the dental pulps in health and disease.

Accelerated orthodontic tooth movement: surgical techniques and the regional acceleratory phenomenon

Background Techniques to accelerate tooth movement have been a topic of interest in orthodontics over the past decade. As orthodontic treatment time is linked to potential detrimental effects, such as increased decalcification, dental caries, root resorption, and gingival inflammation, the possibility of reducing treatment time in orthodontics may provide multiple benefits to the patient. Another reason for the surge in interest in accelerated tooth movement has been the increased interest in adult orthodontics. Review This review summarizes the different methods for surgical acceleration of orthodontic tooth movement. It also describes the advantages and limitations of these techniques, including guidance for future investigations. Conclusions Optimization of the described techniques is still required, but some of the techniques appear to offer the potential for accelerating orthodontic tooth movement and improving outcomes in well-selected cases.

Multivariate GWAS of Structural Dental Anomalies and Dental Caries in a Multi-Ethnic Cohort

Odontogenesis is a complex process, where disruption can result in dental anomalies and/or increase the risk of developing dental caries. Based on previous studies, certain dental anomalies tend to co-occur in patients, suggesting that these traits may share common genetic and etiological components. The main goal of this study was to implement a multivariate genome wide association study approach to identify genetic variants shared between correlated structural dental anomalies and dental caries. Our cohort (N = 3,579) was derived from the Pittsburgh Orofacial Clefts Study, where multiple dental traits were assessed in both the unaffected relatives of orofacial cleft (OFC) cases (n = 2,187) and unaffected controls (n = 1,392). We identified four multivariate patterns of correlated traits in this data: tooth agenesis, impaction, and rotation (AIR); enamel hypoplasia, displacement, and rotation (HDR); displacement, rotation, and mamelon (DRM); and dental caries, tooth agenesis and enamel hypoplasia (CAH). We analyzed each of these four models using genome-wide multivariate tests of association. No genome-wide statistically significant results were found, but we identified multiple suggestive association signals (P ≤ 10−5) near genes with known biological roles during tooth development, including ADAMTS9 and PRICKLE2 associated with AIR; GLIS3, WDR72, and ROR2 associated with HDR and DRM; ROBO2 associated with DRM; BMP7 associated with HDR; and ROBO1, SMAD2, and MSX2 associated with CAH. This is the first study to investigative genetic associations for multivariate patterns of correlated dental anomalies and dental caries. Further studies are needed to replicate these results in independent cohorts.