Integrated hypothesis of dental caries and periodontal diseases

Caries and white spot lesion trajectories of orthodontic patients across an observation period of 20 years

OBJECTIVES

Fixed orthodontic appliances may increase the risk for caries and white spot lesions. The aim of this retrospective study was to determine the long-term associations between both in orthodontic patients.

MATERIALS AND METHODS

103 patients aged 36.6 ± 6.5 years whose fixed appliance orthodontic treatment had finished at least 15 years ago were included. Current clinical data and photographs (T3), panoramic x-ray and photographs from before treatment (T0), after debonding (T1) and at 2-year follow-up (T2) were available. Parameters of interest were dentine caries, "Missing/Filled Teeth" (MFT), "White Spot Lesion" (WSL) index and "Periodontal Screening and Recording" index (PSR; T3 only).

RESULTS

At T0, 30.4% had no caries experience decreasing to 25.6%, 22.4% and 6.8% at T1, T2 and T3 resp. The median MFT (95% CI) at T0, T1, T2 and T3 was 2 (1;3), 3 (2;4), 3 (2;4) and 7 (6;9) resp. increasing significantly at each time point (p < 0.001 each); 30.1% had WSL at debonding. Patients with caries experience at T0 had a 2.4-fold increased risk of WSL at debonding. Dentine caries, caries experience and WSL at T1 were significantly associated with incident caries at T2, but not at T3. PSR at T3 had a significant association with previous caries incidence and WSL.

CONCLUSIONS

Caries experience prior to orthodontic treatment may constitute a risk indicator for WSL, and caries experience and WSL at its end for caries incidence in the near term.

CLINICAL RELEVANCE

Present caries and WSL may help identifying orthodontic patients with special need for prevention and counselling.

Effect of mutanase and dextranase on biofilms of cariogenic bacteria: A systematic review of in vitro studies

Matrix-degrading enzymes are promising non-biocidal adjuncts to dental biofilm control and caries prevention. By disrupting the biofilm matrix structure, enzymes may prevent biofilm formation or disperse established biofilms without compromising the microbial homeostasis in the mouth. This study reviewed whether treatment with mutanase and/or dextranase inhibits cariogenic biofilm growth and/or removes cariogenic biofilms in vitro. An electronic search was conducted in PubMed, EMBASE, Scopus, Web of Science, Cochrane, and LIVIVO databases. Manual searches were performed to identify additional records. Studies that quantitatively measured the effect of mutanase and/or dextranase on the inhibition/removal of in vitro cariogenic biofilms were considered eligible for inclusion. Out of 809 screened records, 34 articles investigating the effect of dextranase (n = 23), mutanase (n = 10), and/or combined enzyme treatment (n = 7) were included in the review. The overall risk of bias of the included studies was moderate. Most investigations used simple biofilm models based on one or few bacterial species and employed treatment times ≥30 min. The current evidence suggests that mutanase and dextranase, applied as single or combined treatment, are able to both inhibit and remove in vitro cariogenic biofilms. The pooled data indicate that enzymes are more effective for biofilm inhibition than removal, and an overall higher effect of mutanase compared to dextranase was observed.

Sugar-sweetened beverage consumption and periodontitis among adults: A population-based cross-sectional study

AIM

Investigating the association between sugar-sweetened beverages (SSBs) and periodontitis and whether the awareness of diabetes modifies this relationship.

MATERIALS AND METHODS

Cross-sectional analysis was conducted using the National Health and Nutrition Examination Survey (NHANES III) data involving US adults aged 30-50. Periodontitis was classified according to the Centers for Disease Control and Prevention and American Academy of Periodontology (CDC-AAP), and SSB consumption as dichotomous (<5 or ≥5, <7 or ≥7 and <14 or ≥14 times/week), ordinal and continuous variables. Confounders included family income poverty ratio, education, race/ethnicity, sex, age, food energy intake, smoking and alcohol. Odds ratios (ORs) were obtained by logistic regressions using inverse probability weighting. Effect modification analysis was performed considering self-reported diabetes.

RESULTS

Among 4473 cases analysed, 198 self-reported diabetes. SSBs were associated with periodontitis when individuals consumed ≥5 (OR 1.64; 95% confidence interval [CI] = 1.30-2.06), ≥7 (OR 1.92; 95% CI = 1.50-2.46) and ≥14 (OR 2.19; 95% CI = 1.50-3.18) times/week. The combined effect of consuming SSBs (≥5 and ≥14 times/week) and self-reported diabetes had less impact than the cumulative effect.

CONCLUSIONS

SSB consumption was associated with higher odds of periodontitis, and the estimates were reduced among those with awareness of diabetes.

The action of microbial collagenases in dentinal matrix degradation in root caries and potential strategies for its management: a comprehensive state-of-the-art review

Conventional views associate microbial biofilm with demineralization in root caries (RC) onset, while research on their collagenases role in the breakdown of collagen matrix has been sporadically developed, primarily in vitro. Recent discoveries, however, reveal proteolytic bacteria enrichment, specially Porphyromonas and other periodontitis-associated bacteria in subgingivally extended lesions, suggesting a potential role in RC by the catabolism of dentin organic matrix. Moreover, genes encoding proteases and bacterial collagenases, including the U32 family collagenases, were found to be overexpressed in both coronal and root dentinal caries. Despite these advancements, to prove microbial collagenolytic proteases' definitive role in RC remains a significant challenge. A more thorough investigation is warranted to explore the potential of anti-collagenolytic agents in modulating biofilm metabolic processes or inhibiting/reducing the size of RC lesions. Prospective treatments targeting collagenases and promoting biomodification through collagen fibril cross-linking show promise for RC prevention and management. However, these studies are currently in the in vitro phase, necessitating additional research to translate findings into clinical applications. This is a comprehensive state-of-the-art review aimed to explore contributing factors to the formation of RC lesions, particularly focusing on collagen degradation in root tissues by microbial collagenases.

Effect of Probiotic Supplements on the Oral Microbiota-A Narrative Review

Data from systematic reviews and meta-analyses show that probiotics positively impact clinical parameters of oral diseases such as gingivitis, dental caries, and periodontitis. However, the working mechanism of probiotics is not fully understood, but is hypothesized to be mediated by direct and indirect interactions with the oral microbiota and the human host. In the present narrative review, we focused on the microbiological effect of probiotic supplements based on data retrieved from randomized clinical trials (RCTs). In addition, we assessed to what extent contemporary molecular methods have been employed in clinical trials in the field of oral probiotics. Multiple RCTs have been performed studying the potential effect of probiotics on gingivitis, dental caries, and periodontitis, as evaluated by microbial endpoints. In general, results are conflicting, with some studies reporting a positive effect, whereas others are not able to record any effect. Major differences in terms of study designs and sample size, as well as delivery route, frequency, and duration of probiotic consumption, hamper comparison across studies. In addition, most RCTs have been performed with a limited sample size using relatively simple methods for microbial identification, such as culturing, qPCR, and DNA-DNA checkerboard, while high-throughput methods such as 16S sequencing have only been employed in a few studies. Currently, state-of-the-art molecular methods such as metagenomics, metatranscriptomics, and metaproteomics have not yet been used in RCTs in the field of probiotics. The present narrative review revealed that the effect of probiotic supplements on the oral microbiota remains largely uncovered. One important reason is that most RCTs are performed without studying the microbiological effect. To facilitate future systematic reviews and meta-analyses, an internationally agreed core outcome set for the reporting of microbial endpoints in clinical trials would be desirable. Such a standardized collection of outcomes would most likely improve the quality of probiotic research in the oral context.

Influence of Biofilm Maturity on the Antibacterial Efficacy of Cold Atmospheric Plasma in Oral Microcosm Biofilms

As biofilms mature, biomass and extracellular polysaccharide (EPS) content increases, enhancing pathogenicity. Therefore, this study aimed to evaluate the antibacterial efficacy of cold atmospheric plasma (CAP) against oral microcosm biofilms and the influence of biofilm maturity on treatment. Oral microcosm biofilms were cultured on hydroxyapatite disks for 2 and 6 days. Based on the treatment and biofilm maturity, these were subsequently allocated into six groups (N = 19 each): Groups 1 and 2 were incubated with distilled water for 1 min; Groups 3 and 4 were treated with CAP for 2 min, and Groups 5 and 6 were treated with 0.12% chlorhexidine gluconate for 1 min. Groups 1, 3, and 5 represent 2-day biofilms, and Groups 2, 4, and 6 represent 6-day biofilms. Treatments were repeated daily for 5 days. Antibacterial efficacy was analyzed by measuring oral biofilms' red fluorescence intensity (RatioR/G) and quantifying EPS content and bacterial viability. The RatioR/G was 1.089-fold and 1.104-fold higher in Groups 4 and 6 than in Groups 3 and 5 following antibacterial treatment, respectively (p < 0.001). EPS content increased by 1.71-fold in Group 6 than in Group 5 (p < 0.001). Bacterial survival rate was the lowest in Group 3 (p = 0.005). These findings underscore the relevance of CAP treatment in maintaining antibacterial efficacy regardless of the biofilm development stage, highlighting its potential utility in oral care.

Association between prenatal vitamin D deficiency with dental caries in infants and children: a systematic review and meta-analysis

Prenatal vitamin D (PVD) is a vital micronutrient for dental caries (DCs). The association between prenatal vitamin D deficiencies (PVDD) and DCs in children has been conflicting in different reports. This meta-analysis aimed to investigate the association between PVDD and DCs in children for the first time. We searched PubMed, Scopus, Web of Sciences, Embase, and Scholar databases to find relevant studies based on mesh terms from 2000 to October 2023. This study was conducted based on the 2020 version of the PRISMA checklist. Cochran's Q and I2 tests were used to evaluate heterogeneity between studies. Egger's test was used to evaluate publication bias. The effect size of the association between PVDD and DCs was reported by the odds ratio (OR) at the 95% confidence interval (95% CI).Twelve studies, including 11,021 participants, were reviewed. The pooled prevalence of PVDD was estimated at 4353 (32%). The prevalence of DCs in children of mothers with and without PVDD was 44% and 25%, respectively. PVDD was significantly associated with an increased risk of DCs in children (OR: 1.35, 95% CI (1.22, 1.47), I2 = 86.6%). The association of DCs with PVDD was different based on gestational age groups, children's age groups, and vitamin D levels. This meta-analysis showed PVDD can be associated with an increased risk of DCs in children, especially in mothers with prenatal vitamin D levels ≤ 35 nmol/L. Adequate vitamin D levels throughout pregnancy can help prevent DCs in children.

Effects of glucose and lactate on Streptococcus mutans abundance in a novel multispecies oral biofilm model

The oral microbiome plays an important role in protecting oral health. Here, we established a controlled mixed-species in vitro biofilm model and used it to assess the impact of glucose and lactate on the ability of Streptococcus mutans, an acidogenic and aciduric species, to compete with commensal oral bacteria. A chemically defined medium was developed that supported the growth of S. mutans and four common early colonizers of dental plaque: Streptococcus gordonii, Actinomyces oris, Neisseria subflava, and Veillonella parvula. Biofilms containing the early colonizers were developed in a continuous flow bioreactor, exposed to S. mutans, and incubated for up to 7 days. The abundance of bacteria was estimated by quantitative polymerase chain reaction (qPCR). At high glucose and high lactate, the pH in bulk fluid rapidly decreased to approximately 5.2, and S. mutans outgrew other species in biofilms. In low glucose and high lactate, the pH remained above 5.5, and V. parvula was the most abundant species in biofilms. By contrast, in low glucose and low lactate, the pH remained above 6.0 throughout the experiment, and the microbial community in biofilms was relatively balanced. Fluorescence in situ hybridization confirmed that all species were present in the biofilm and the majority of cells were viable using live/dead staining. These data demonstrate that carbon source concentration is critical for microbial homeostasis in model oral biofilms. Furthermore, we established an experimental system that can support the development of computational models to predict transitions to microbial dysbiosis based on metabolic interactions.IMPORTANCEWe developed a controlled (by removing host factor) dynamic system metabolically representative of early colonization of Streptococcus mutans not measurable in vivo. Hypotheses on factors influencing S. mutans colonization, such as community composition and inoculation sequence and the effect of metabolite concentrations, can be tested and used to predict the effect of interventions such as dietary modifications or the use of toothpaste or mouthwash on S. mutans colonization. The defined in vitro model (species and medium) can be simulated in an in silico model to explore more of the parameter space.

Periodontal index and salivary Ph in first trimester´s pregnant women: A cross-sectional study

Background

Recent reviews have suggested a possible association between periodontal disease and increasing risks during pregnancy, such as newborn low weight, premature birth, gestational diabetes mellitus and preeclampsia. Besides, being saliva a valuable source of information on general and buccal health, it is necessary to know its parameters associated with periodontal diseases; in order to help odontologists to better understand this disease, and provide a sound clinical treatment. Therefore, this research sought to assess the correlation between periodontal index, and salivary pH on first trimester pregnant women.

Material and Methods

71 pregnant women were evaluated by observational, transversal and correlational study, using the community periodontal index and salivary pH-meter. The Spearman coefficient was employed, considering a p value of 0.05.

Results

A correlation was found between periodontal index and salivary pH in first trimester pregnant women (p=0.039). According to age, correlations were found to be very weak in age group 18 to 24 years (p=0.605), and age group 25 to 35 years (p=0.071). Similarly, no strong correlation was found when pairing based on number of pregnancies (primiparous p=0.239 and multi pregnancy p=0.114). Also, 36.6% of pregnant women showed periodontal pockets smaller than 5 mm.

Conclusions

With lower salivary pH, the periodontal index in pregnant women gets lower; however, no correlation could be found between age group and number of pregnancies. Key words:Periodontal index, periodontal pocket, periodontal diseases, saliva, pregnancy, pregnant women.

Is Diet a Determining Factor in the Induction of Gingival Inflammation by Dental Plaque? A Secondary Analysis of Clinical Studies

The aim was to determine the association between plaque and gingival inflammation reported by dietary interventions. Data of four clinical studies dealing with changed nutrition and gingival examination were reanalyzed with regard to gingival inflammation (GI), plaque (PI), and bleeding on probing (BOP). Dietary changes basically involved avoiding sugar, white flour and sweetened drinks and focusing on whole foods for 4 weeks. The control groups were to maintain their usual diet. All participants had to reduce their oral hygiene efforts. Linear regression models taking the clustering of the data due to several studies into account were applied. In total, data of 92 participants (control groups: 39, test-groups 53) were reanalyzed. While both groups showed a slight increase in dental plaque, only the test groups showed a significant decrease in inflammatory parameters: GI (mean value difference End-Baseline (Δ): -0.31 (±SD 0.36)) and BOP (Δ: -15.39% (±16.07)), both p < 0.001. In the control groups, there was a constant relation between PI and GI, while the experimental group showed a decreasing relationship in GI/PI (p = 0.016), and even an inverted relationship BOP/PI under a changed diet (p = 0.031). In conclusion, diet seems to be a determining factor how the gingiva reacts towards dental plaque.

Sugar intake above international recommendations and oral disease burden: A population-based study

OBJECTIVE

To evaluate the association between added sugar intake above the daily limit for the risk of noncommunicable diseases (NCDs) and the Chronic Oral Disease Burden in adolescents.

METHODS

This was a population-based study using cross-sectional data nested to RPS Cohorts Consortium, São Luís, Brazil, from the 18-19-year-old follow-up (n = 2515). High consumption of added sugars was estimated according to the limits of the World Health Organization guidelines (WHO) (≥5% of total energy/day) and the American Heart Association statement (AHA) (≥25 g/day). The Chronic Oral Disease Burden was a latent variable (number of decayed teeth, periodontal probing depth ≥4 mm, clinical attachment level ≥3 mm, and bleeding on probing). Models were adjusted for Socioeconomic Status, sex, obesity, and plaque index and analyzed through structural equation modeling.

RESULTS

Adolescents had high sugar consumption according to the WHO (78.6%) and AHA (81.4%) recommendations. High sugar intake, according to WHO (SC = 0.096; p = 0.007) and AHA (SC = 0.056; p = 0.027), was associated with a heavier Chronic Oral Disease Burden. Even half of the recommended dose was sufficient to affect some oral disease indicators.

CONCLUSION

Sugar intake over international statements to prevent NCDs is associated with higher Chronic Oral Disease Burden among adolescents.

The impact of ketogenic diet on some metabolic and non-metabolic diseases: Evidence from human and animal model experiments

The ketogenic diet (KD) is recognized as minimum carbohydrate and maximum fat intakes, which leads to ketosis stimulation, a state that is thought to metabolize fat more than carbohydrates for energy supply. KD has gained more interest in recent years and is for many purposes, including weight loss and managing serious diseases like type 2 diabetes. On the other hand, many believe that KD has safety issues and are uncertain about the health drawbacks. Thus, the outcomes of the effect of KD on metabolic and non-metabolic disease remain disputable. The current narrative review aims to evaluate the effect of KD on several diseases concerning the human health. To our best knowledge, the first report aims to investigate the efficacy of KD on multiple human health issues including type 2 diabetes and weight loss, cardiovascular disease, kidney failure and hypertension, non-alcoholic fatty liver, mental problem, oral health, libido, and osteoporosis. The literature searches were performed in Databases, PubMed, Scopus, and web of Science looking for both animal and human model designs. The results heterogeneity seems to be explained by differences in diet composition and duration. Also, the available findings may show that proper control of carbohydrates, a significant reduction in glycemic control and glycated hemoglobin, and weight loss by KD can be an approach to improve diabetes and obesity, hypertension, non-alcoholic fatty liver, PCOS, libido, oral health, and mental problem if isocaloric is considered. However, for some other diseases like cardiovascular disease and osteoporosis, more robust data are needed. Therefore, there is robust data to support the notion that KD can be effective for some metabolic and non-metabolic diseases but not for all of them. So they have to be followed cautiously and under the supervision of health professionals.

Combined effect of dietary calcium consumption and physical activity on dental caries in children and adolescents: a study of the NHANES database

BACKGROUND

Calcium (Ca) is a nutritional factor that associated with dental caries. A recent study showed that in the case of adequate Ca intake, a higher level of physical activity may contribute to bone mass accumulation. However, the combined effect between Ca intake and physical activity on caries experience is unclear. Herein, we aimed to explore the above combined effect on dental caries in children and adolescents.

METHODS

Data of 5,917 children and adolescents were extracted from the National Health and Nutrition Examination Surveys (NHANES) database in 2015-2020 in this cross-sectional study. The NHANES assessed the dietary Ca intake through the 24-hour dietary recalls, and the physical activity level was self-reported using the questionnaires. Also, the dental caries was diagnosed according to the Decayed, Missing and Filled Teeth/Surfaces (DMFT/S) index. Weighted univariate and multivariate logistic regression analyses were utilized to screen the covariates and to investigate the associations of dietary Ca intake and physical activity with dental caries, respectively, and assess the combined effect between dietary Ca intake and physical activity on dental caries. The evaluation indexes were odd ratios (ORs) and 95% confidence intervals (CIs). Subgroup analyses of age, obesity, and total sugar intake were also performed.

RESULTS

Among the eligible participants, 2,687 had caries experience. After adjusting for the covariates, we found that children and adolescents who not reach the recommendation level of Ca intake combined with physical activity less than 7 time in 1 week seemed to have higher odds of dental caries [OR = 1.77, 95%CI: (1.38-2.27)], compared with those who reached the standards. In addition, this potential combined effect was also found in age < 12 years old [OR = 1.62, 95%CI: (1.23-2.14)], non-obesity [OR = 1.88, 95%CI: (1.49-2.35)], and total sugar intake (all P < 0.05) subgroups.

CONCLUSIONS

Ca intake and physical activity had a potential combined effect on dental caries in children and adolescents, but the causal relationships between them needed further clarification.

Evidence Supporting Oral Hygiene Management by Owners through a Genetic Analysis of Dental Plaque Bacteria in Dogs

With the increase in the number of households raising dogs and the reports of human-to-dog transmission of oral bacteria, concerns about dogs' oral health and the need for oral hygiene management are increasing. In this study, the owners' perceptions about their dogs' oral health and the frequency of oral hygiene were determined along with the analysis of dog dental plaque bacteria through metagenomic amplicon sequencing so as to support the need for oral hygiene management for dogs. Although the perception of 63.2% of the owners about their dogs' oral health was consistent with the veterinarian's diagnosis, the owners' oral hygiene practices regarding their dogs were very poor. The calculi index (CI) and gingiva index (GI) were lower in dogs who had their teeth brushed more than once a week (57.89%) than in dogs brushed less than once a month (42.10%); however, the difference was nonsignificant (CI: p = 0.479, GI: p = 0.840). Genomic DNA was extracted from dental plaque bacteria removed during dog teeth scaling, and metagenomic amplicons were sequenced. The 16S amplicons of 73 species were identified from among the plaque bacteria of the dogs. These amplicons were of oral disease-causing bacteria in humans and dogs. The 16S amplicon of Streptococcus mutans matched that of the human S. mutans, with type c identified as the main serotype. This result suggests that human oral bacteria can be transmitted to dogs. Therefore, considering the high frequency of contact between dogs and humans because of communal living and the current poor oral health of dogs, owners must improve the oral hygiene management of their dogs.

Changes in the Composition of Unstimulated and Stimulated Saliva Due to Chewing Sour Cherry Gum and a Toothbrush Change

BACKGROUND

Our previous studies demonstrated that sour cherry anthocyanins (AC) reduce the salivary count of Streptococcus mutans and inhibit salivary amylase activity within 30 minutes after chewing AC gum. AC gum and changing toothbrushes after scaling reduced the Gram-negative species in the unstimulated salivary microbiota. The present study examined the effect of AC gums on salivary factors, including changes in microbiome.

METHODS

The study was conducted over three weeks with two groups; young adults (18-30) and adults (30-45). Ten participants changed their toothbrushes, while the other 10 participants did not change after the control period. After scaling, all participants received three doses of AC gum daily. The salivary mRNA and protein levels of cytokines, mucins, melatonin, and the microbiota of unstimulated and stimulated saliva were determined by polymerase chain reaction, enzyme-linked immunosorbent assay, and 16S rRNA gene sequencing.

RESULTS

Significantly higher levels of tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), mucin5B (MUC5B), mucin7 (MUC7), and melatonin were detected in stimulated saliva. Correlation analysis of these factors with the microbiota showed positive correlations with the genera Lachnospiraceae, Eikenella, Saccharibacteria_(TM7), Streptococcus, Prevotella, and Haemophilus.

CONCLUSIONS

AC chewing gum has a beneficial effect on the composition of the oral microbiome, and toothbrush replacement leads to changes in the levels of salivary pro-inflammatory cytokines.

Empirically derived dietary patterns in relation to periodontitis and number of teeth among Norwegian adults

OBJECTIVES

To explore dietary patterns in relation to periodontitis and number of teeth.

DESIGN

A cross-sectional study.

SETTING

We used data from the seventh survey of the Tromsø Study in Norway, 2015-2016. Three periodontitis groups were compared: (i) no periodontitis/slow bone loss; (ii) moderate bone loss; and (iii) rapid bone loss. Number of teeth was categorised as 25-28, 20-24 and ≤ 19. Dietary patterns were identified by principal component analysis. Multiple logistic regression was applied to examine associations between tertiles of dietary pattern scores and periodontitis, and between these same tertiles and number of teeth.

PARTICIPANTS

1487 participants (55·5 % women) aged 40-79 years who were free of major chronic diseases, attended an oral health examination and completed a FFQ.

RESULTS

Four dietary patterns were identified, which explained 24 % of the total variability in food intake: fruit and vegetables, Westernised, meat/fish and potatoes, and refined grain and dessert. The fruit and vegetables pattern was inversely associated with periodontitis characterised by rapid bone loss when compared with no periodontitis/slow bone loss (OR tertile 3 v. 1 0·49, 95 % CI: 0·25, 0·98). Participants who were in the highest tertile of the refined grain and dessert pattern (tertile 3 v. 1) had 2·38- and 3·52-fold increased odds of having ≤ 19 than 20-24 and 25-28 teeth, respectively.

CONCLUSION

Out of four identified dietary patterns, only the fruit and vegetables pattern was negatively associated with advanced periodontitis. A more apparent positive association was observed between the refined grain and dessert pattern and having fewer teeth (≤ nineteen teeth).

Atomic force microscopy-mediated mechanobiological profiling of complex human tissues

Tissue mechanobiology is an emerging field with the overarching goal of understanding the interplay between biophysical and biochemical responses affecting development, physiology, and disease. Changes in mechanical properties including stiffness and viscosity have been shown to describe how cells and tissues respond to mechanical cues and modify critical biological functions. To quantitatively characterize the mechanical properties of tissues at physiologically relevant conditions, atomic force microscopy (AFM) has emerged as a highly versatile biomechanical technology. In this review, we describe the fundamental principles of AFM, typical AFM modalities used for tissue mechanics, and commonly used elastic and viscoelastic contact mechanics models to characterize complex human tissues. Furthermore, we discuss the application of AFM-based mechanobiology to characterize the mechanical responses within complex human tissues to track their developmental, physiological/functional, and diseased states, including oral, hearing, and cancer-related tissues. Finally, we discuss the current outlook and challenges to further advance the field of tissue mechanobiology. Altogether, AFM-based tissue mechanobiology provides a mechanistic understanding of biological processes governing the unique functions of tissues.

Examining the Role of Vitamin D in Caries Susceptibility in Children's Deciduous Teeth: A Systematic Review

The global prevalence of dental caries in deciduous teeth remains a significant health concern, affecting almost 70% of children by the age of six in specific regions. This systematic review aspired to methodically investigate the association between vitamin D levels and susceptibility to caries in children's deciduous teeth. A detailed search, guided by the PRISMA and PROSPERO guidelines, was conducted across three prominent electronic databases: PubMed, Web of Science, and Scopus, culminating in August 2023. The search integrated various keywords related to vitamin D and dental caries in primary dentition, yielding an initial pool of 1678 articles. After meticulous scrutiny, seven studies with a total of 7655 participants were deemed suitable for inclusion. The studies represented diverse geographical regions, showcasing varied vitamin D levels and sun exposure. Patient habits like brushing frequency, dental visits, and vitamin consumption also varied across studies. The analysis pinpointed vitamin D deficiency as a potential risk factor in some of the studies, with Odds Ratios (OR) ranging from 0.68 to 2.15. Statistically significant associations between vitamin D deficiency and caries susceptibility were documented in three studies (ORs of 2.15, 1.98, and 1.70). This comprehensive review elucidates the complex relationship between vitamin D levels and dental caries in children's deciduous teeth. While some studies spotlight vitamin D's pivotal role in dental health, inconsistencies across studies and regional differences necessitate more in-depth, globally representative investigations. Ensuring optimal vitamin D levels may play an integral role in dental health strategies. However, it is important to highlight that the roles of these studied factors might differ in deciduous teeth compared to permanent teeth.

Probiotics Partly Suppress the Impact of Sugar Stress on the Oral Microbiota-A Randomized, Double-Blinded, Placebo-Controlled Trial

The aim was to test if probiotics counteract oral dysbiosis during 14 days of sugar stress and subsequently help restore oral homeostasis. Eighty healthy individuals received either probiotics (n = 40) or placebo lozenges (n = 40) for 28 days and rinsed with a 10% sucrose solution 6-8 times during the initial 14 days of the trial. Saliva and supragingival samples were collected at baseline, day 14, and day 28. Saliva samples were analyzed for levels of pro-inflammatory cytokines, albumin, and salivary enzyme activity. The supragingival microbiota was characterized according to the Human Oral Microbiome Database. After 14 days of sugar stress, the relative abundance of Porphyromonas species was significantly higher (p = 0.03) and remained significantly elevated at day 28 in the probiotic group compared to the placebo group (p = 0.004). At day 28, the relative abundance of Kingella species was significantly higher in the probiotic group (p = 0.03). Streptococcus gordinii and Neisseria elongata were associated with the probiotic group on day 28, while Streptococcus sobrinus was associated with the placebo group on day 14 and day 28. On day 28, the salivary albumin level was significantly lower in the probiotic group. The present study demonstrates a potential stabilizing effect on the supragingival microbiota mediated by consumption of probiotics during short-term sugar stress.

Association between dietary quality and the prevalence of periodontitis in older Korean adults aged 60 or over

PURPOSE

This study investigated the association between dietary quality and the prevalence of periodontitis in older Korean adults (≥60 years of age) using data from the seventh Korea National Health and Nutrition Examination Survey (KNHANES VII, 2016-2018).

METHODS

Among the 16,489 KNHANES participants from 2016-2018, those aged ≥60 years were selected as the eligible population. After applying our exclusion criteria, 3,527 participants were included in the final study population. Periodontal status was measured using the Community Periodontal Index (CPI). To determine the association between dietary quality and the prevalence of periodontitis, analysis of variance, the chi-square (χ²) test, and logistic regression analysis were performed.

RESULTS

The population was divided into quartile groups and stratified by sex. The percentage of men and women with periodontitis was 54.34% and 42.74%, respectively. The quartile with higher Korean Healthy Eating Index scores had a lower percentage of people with periodontitis in both sexes. For men, only vegetable intake showed a significant difference between sub-groups with or without periodontitis, whereas, for women, the intake of fruits, milk, sweets, carbohydrates, and fats showed significant differences. There was a strong positive association between vegetable intake and periodontitis in men in the 3 models used in this study; model 3 had an adjusted odds ratio (aOR) of 1.367 (95% confidence interval [CI], 1.091-1.712). In women, a strong positive association with periodontitis was shown for sweets in all 3 models, with an aOR of 1.477 in model 3 (95% CI, 1.125-1.939).

CONCLUSIONS

Dietary quality was inversely associated with the prevalence of periodontitis in Korean adults aged ≥60 years. Further comprehensive studies are needed to help establish nutrition and health policies for older adults in Korea.

Presence of host and bacterial-derived collagenolytic proteases in carious dentin: a systematic review of ex vivo studies

Introduction and aim

The presence of host collagenases in the degradation of the protein matrix at later stages of carious dentin lesions development, as well as the potential involvement of bacterial collagenases, have been suggested but lack conclusive evidence. This study aims to conduct a systematic review to comprehensively assess the profile of host and bacterial-derived collagenolytic proteases in both root and coronal dentin carious lesions.

Methods

The search was performed in eight databases and the grey literature. Studies evaluating ex vivo dentin, extracted teeth, or biofilms from natural caries lesions were included. The methodological quality of studies was assessed using the Joanna Briggs Institute tool. Synthesis of the results and the certainty of evidence were performed following the Synthesis without Meta-analysis (SWiM) checklist and GRADE approach for narrative synthesis, respectively.

Results

From 935 recovered articles, 18 were included. Although the evidence was very uncertain, it was possible to suggest that 1) MMP-2, MMP-9, MMP-13, and CT-B may be increased in carious dentin when compared to sound dentin; 2) there is no difference in MMP-2 presence, while MMP-13 may be increased in root when compared to coronal carious dentin; 3) there is no difference of MMP-2 and MMP-9 expression/activity before and after cavity sealing; 4) MMP-8 may be increased in the dentin before cavity sealing compared to dentin after cavity sealing; 5) there is no difference of MMP-20 in irradiated vs. non-irradiated carious dentin. MMP-20 probably reduces in carious outer dentin when compared to carious inner dentin (moderate certainty). Genes encoding bacterial collagenolytic proteases and protein-degrading bacteria were detected in coronal and root carious lesions.

Conclusion

Trends in the direction of the effect were observed for some collagenolytic proteases in carious dentin, which may represent a potential target for the development of new treatments. (Protocol register-PROSPERO: CRD42020213141).

Recombinant Prevotella melaninogenica α-1,3 glucanase and Capnocytophaga ochracea α-1,6 glucanase as enzymatic tools for in vitro degradation of S. mutans biofilms

Dental biofilms represent a serious oral health problem playing a key role in the development of caries and other oral diseases. In the present work, we cloned and expressed in E. coli two glucanases, Prevotella melaninogenica mutanase (PmGH87) and Capnocytophaga ochracea dextranase (CoGH66), and characterized them biochemically and biophysically. Their three-dimensional structures were elucidated and discussed. Furthermore, we tested the capacity of the enzymes to hydrolyze mutan and dextran to prevent formation of Streptococcus mutans biofilms, as well as to degrade pre- formed biofilms in low and abundant sugar conditions. The percentage of residual biofilm was calculated for each treatment group in relation to the control, as well as the degree of synergism. Our results suggest that both PmGH87 and CoGH66 are capable of inhibiting biofilm formation grown under limited or abundant sucrose conditions. Degradation of pre-formed biofilms experiments reveal a time-dependent effect for the treatment with each enzyme alone. In addition, a synergistic and dose-dependent effects of the combined enzymatic treatment with the enzymes were observed. For instance, the highest biomass degradation was 95.5% after 30 min treatment for the biofilm grown in low sucrose concentration, and 93.8% after 2 h treatment for the biofilm grown in sugar abundant condition. Strong synergistic effects were observed, with calculated degree of synergism of 5.54 and 3.18, respectively and their structural basis was discussed. Jointly, these data can pave the ground for the development of biomedical applications of the enzymes for controlling growth and promoting degradation of established oral biofilms.

The Complicated Relationship of Short-Chain Fatty Acids and Oral Microbiome: A Narrative Review

The human oral microbiome has emerged as a focal point of research due to its profound implications for human health. The involvement of short-chain fatty acids in oral microbiome composition, oral health, and chronic inflammation is gaining increasing attention. In this narrative review, the results of early in vitro, in vivo, and pilot clinical studies and research projects are presented in order to define the boundaries of this new complicated issue. According to the results, the current research data are disputable and ambiguous. When investigating the role of SCFAs in human health and disease, it is crucial to distinguish between their local GI effects and the systemic influences. Locally, SCFAs are a part of normal oral microbiota metabolism, but the increased formation of SCFAs usually attribute to dysbiosis; excess SCFAs participate in the development of local oral diseases and in oral biota gut colonization and dysbiosis. On the other hand, a number of studies have established the positive impact of SCFAs on human health as a whole, including the reduction of chronic systemic inflammation, improvement of metabolic processes, and decrease of some types of cancer incidence. Thus, a complex and sophisticated approach with consideration of origin and localization for SCFA function assessment is demanded. Therefore, more research, especially clinical research, is needed to investigate the complicated relationship of SCFAs with health and disease and their potential role in prevention and treatment.

Can acid produced from probiotic bacteria alter the surface roughness, microhardness, and elemental composition of enamel? An in vitro study

Probiotics are live microorganisms that upon administration in adequate amounts provide various health benefits to the host. Probiotics are "lactic acid-producing bacteria" as they release large amounts of organic acids, particularly lactic acids, in their surrounding environment. Although the acids produced by probiotics are beneficial for gastrointestinal and vaginal health, the acidogenic nature of probiotics has raised concerns among dental professionals, especially concerning their effect on the enamel and dentin. Previous studies have found that probiotics can lower the pH of the saliva and cause essential elements like Calcium and Phosphorus to leach from the enamel. This can alter the surface topography of enamel and increase the risk of enamel defects. Studies have also noted that probiotic bacteria can replace cariogenic bacteria and lower the risk of tooth decay. However, the effect of acid produced by probiotics on the enamel surface remains unclear. Hence, the present study aims to evaluate the effect of probiotics on the surface roughness, microhardness, and elemental composition of enamel compared to 0.1 M Lactic acid (demineralizing agent). Twenty enamel sections were randomly divided into groups and subjected to a pH cycling model using a probiotic suspension and 0.1 M lactic acid. The changes in the surface roughness, microhardness, surface morphology, and elemental composition of the enamel with regard to Carbon, Oxygen, Sodium, Hydrogen, Magnesium, Phosphorus, Fluoride, Chlorine, and Calcium of the enamel were evaluated before and after the emersion in both the groups. The results showed a significant increase in the mean surface roughness in the probiotic group before and after the exposure. The microhardness of the enamel decreased along with altered arrangement of the enamel prisms, increased striations, scratch marks, and pitting after exposure to the probiotic group. A decrease in the atomic/weight% for Calcium, Phosphorous, Fluoride, Aluminium, and Oxygen and an increase in the weight/atomic% for Carbon, Nitrogen, and Sodium were noted compared to the baseline in the probiotic solution. The results in the probiotic group were comparable to the 0.1 M lactic acids. The pH changed from 5.78 to 3.06 at the end of 24 h in the probiotic group. Based on these findings, we conclude that exposure to probiotics can affect microhardness and surface roughness and cause leaching of essential elements like Calcium and Phosphorous from the enamel.

Salivary metabolomic profile associated with cariogenic risk in children

OBJECTIVES

To identify the metabolomic differences in the saliva of healthy children versus children with active carious lesions and to estimate the predictive capacity of a model based on the salivary metabolomic profile.

METHODS

A study of cases (n = 31) and controls (n = 37) was designed for children aged between 6 and 12 (mean age of the cases: 8.9; controls: 8.7). The said children attended public health centers in Valencia, Spain. Intraoral examinations were performed by a single examiner using ICDAS II diagnostic criteria. Unstimulated total saliva samples were analyzed by nuclear magnetic resonance (NMR) spectroscopy.

RESULTS

The dft index for cases was 2.84 while it was 0.19 for the control group, the DMFT index was 1.13 and 0.11, respectively. The predictive model generated by the multivariate PLS-DA analysis projects a separation between the cases and the controls on the score chart with a predictive capacity and generating an area under the curve of 0.71. The metabolites: 3-methyl-2-oxovalerate, 3-hydroxybutyrate, lactate, acetone, citrate, ornithine, ethanolamine, taurine, proline, glycine, mannose, glucose, 1-6-Anhydro-β-d-glucose and citraconate, are those that show greater significance in the model. In the controls, glycine (Cohen's d = 0.430) and glucose (Cohen's d = 0.560) present higher means compared to the cases. On the contrary, taurine (Cohen's d= -0.474) and mannose (Cohen's d= -0.456) show higher means in cases compared to controls.

CONCLUSIONS

Our findings show a difference in the salivary metabolomic profiles, specifically in the groups of saccharides and amino acids, suggesting an association of these with the level of caries risk.

CLINICAL SIGNIFICANCE

The results reported in the present study reinforce the use of salivary metabolomics as a research method for the search for salivary biomarkers that allow the evaluation of caries risk in patients. Furthermore, it brings us closer to a personalized medicine that will help in dental caries prevention strategies.

The Association Between Long-Term Corticosteroids Use and Dental Caries: A Systematic Review

Corticosteroids (CSs) are a group of medications prescribed regularly to treat a wide range of inflammatory and immune-related conditions with great benefit. The impact of long-term use of CSs on the oral cavity has been reported before, including increased risk of periodontal disease and dental caries. Thus, the aim of this study is to evaluate the prevalence of dental caries in patients using CSs. A literature review was completed using PubMed and Cochrane search engines. The search was based on questions related to adults and children (P); corticosteroids (I); no corticosteroids (C); and dental caries (O) (PICO questions) using the keywords "steroids" and "caries" with all relevant variations and MeSH terms. Decay missing filling tooth/decay missing filling surface (DMFT/DMFS) scores were selected as parameters to assess the effects of CSs on caries prevalence. Data was extracted and analyzed for comparisons. The search yielded 1,206 articles from January 2001 to January 2023, of which 21 papers were eligible for analysis. Overall, 14 studies reported an increase in caries with CSs use. However, seven studies failed to report an association of caries prevalence with CSs use. Current evidence supports the correlation between increased risk of caries with chronic CSs use, specifically for inhaler formulation. Future studies with randomized controlled clinical studies are warranted to confirm these findings.

A Cross-Sectional Study of Oral Health Status and Behavioral Risk Indicators among Non-Smoking and Currently Smoking Lithuanian Adolescents

The purpose of this study was to evaluate oral health status, behavioral risk indicators, and the impact of smoking on oral health among Lithuanian adolescents. This representative cross-sectional study was conducted among 15-year-old Lithuanian adolescents. The method of multistage cluster sampling was used. A total of 1127 adolescents met the inclusion criteria. Two originally created self-reported questionnaires were used in this study. Dental caries, periodontal status, and oral hygiene status were evaluated by four trained researchers. A p-value ≤ 0.05 was set to indicate statistically significant differences. Statistical analysis included Mann-Whitney, Kruskal-Wallis, and Spearman correlation tests. Out of all the participants, 9.6% self-reported being a current tobacco smoker. The mean PI value was 1.14 ± 0.69 among all the participants. Currently smoking adolescents had more active caries lesions (D-S) than those who did not smoke (13.2 ± 16.4 vs. 9.8 ± 10.7, p = 0.023). Considering periodontal status, non-smoking adolescents had significantly lower mean PSR index scores than current smokers (0.52 ± 0.51 vs. 0.61 ± 0.50, p = 0.0298). Tobacco smoking and the consumption of energy drinks were significantly associated (OR = 3.74, 95% CI 2.66-5.26, p < 0.001) among participants. Currently smoking adolescents tended to have improper dietary habits, especially a higher consumption of energy drinks; thus, they were more likely to have active dental caries lesions, as well as poorer periodontal status, than their non-smoking peers.

Obesity, Insulin Resistance, Caries, and Periodontitis: Syndemic Framework

(1) Background: To investigate the grouping of obesity and insulin resistance with caries and periodontitis from a syndemic perspective through pathways of socioeconomic inequalities, smoking, alcohol, and high sugar consumption in adolescence. (2) Methods: The population-based RPS Cohort study, São Luís, Brazil, in ages 18-19 years (n = 2515) was used. The outcomes were the grouping of pbesity and Insulin Resistance Phenotype (latent variable formed by Triglycerides/HDL ratio, TyG index, and VLDL) and the Chronic Oral Disease Burden (latent variable comprising caries, bleeding on probing, probing depth ≥ 4 mm, clinical attachment level ≥ 3 mm, and visible plaque index ≥ 15%). Socioeconomic Inequalities influencing the Behavioral Risk Factors (latent variable formed by added sugar, smoking, and alcohol) were analyzed using structural equation modeling. (3) Results: Socioeconomic Inequalities were associated with the Chronic Oral Disease Burden [Standardized Coefficient (SC) = 0.222, p < 0.001]. Behavioral Risk Factors were associated with increased Chronic Oral Disease Burden (SC = 0.103; p = 0.013). Obesity was associated with the Insulin Resistance Phenotype (SC = 0.072; p < 0.001) and the Chronic Oral Disease Burden (SC = 0.066; p = 0.005). The Insulin Resistance Phenotype and the Chronic Oral Disease Burden were associated (SC = 0.053; p = 0.032). (4) Conclusion: The grouping of obesity and early events of diabetes with caries and periodontitis call for a syndemic approach in adolescence.

Microbial metabolites in the pathogenesis of periodontal diseases: a narrative review

The purpose of this narrative review is to highlight the importance of microbial metabolites in the pathogenesis of periodontal diseases. These diseases, involving gingivitis and periodontitis are inflammatory conditions initiated and maintained by the polymicrobial dental plaque/biofilm. Gingivitis is a reversible inflammatory condition while periodontitis involves also irreversible destruction of the periodontal tissues including the alveolar bone. The inflammatory response of the host is a natural reaction to the formation of plaque and the continuous release of metabolic waste products. The microorganisms grow in a nutritious and shielded niche in the periodontal pocket, protected from natural cleaning forces such as saliva. It is a paradox that the consequences of the enhanced inflammatory reaction also enable more slow-growing, fastidious, anaerobic bacteria, with often complex metabolic pathways, to colonize and thrive. Based on complex food chains, nutrient networks and bacterial interactions, a diverse microbial community is formed and established in the gingival pocket. This microbiota is dominated by anaerobic, often motile, Gram-negatives with proteolytic metabolism. Although this alternation in bacterial composition often is considered pathologic, it is a natural development that is promoted by ecological factors and not necessarily a true "dysbiosis". Normal commensals are adapting to the gingival crevice when tooth cleaning procedures are absent. The proteolytic metabolism is highly complex and involves a number of metabolic pathways with production of a cascade of metabolites in an unspecific manner. The metabolites involve short chain fatty acids (SCFAs; formic, acetic, propionic, butyric, and valeric acid), amines (indole, scatole, cadaverine, putrescine, spermine, spermidine) and gases (NH₃, CO, NO, H₂S, H₂). A homeostatic condition is often present between the colonizers and the host response, where continuous metabolic fluctuations are balanced by the inflammatory response. While it is well established that the effect of the dental biofilm on the host response and tissue repair is mediated by microbial metabolites, the mechanisms behind the tissue destruction (loss of clinical attachment and bone) are still poorly understood. Studies addressing the functions of the microbiota, the metabolites, and how they interplay with host tissues and cells, are therefore warranted.

Association of polymicrobial interactions with dental caries development and prevention

Dental caries is a common oral disease. In many cases, disruption of the ecological balance of the oral cavity can result in the occurrence of dental caries. There are many cariogenic microbiota and factors, and their identification allows us to take corresponding prevention and control measures. With the development of microbiology, the caries-causing bacteria have evolved from the traditional single Streptococcus mutans to the discovery of oral symbiotic bacteria. Thus it is necessary to systematically organized the association of polymicrobial interactions with dental caries development. In terms of ecology, caries occurs due to an ecological imbalance of the microbiota, caused by the growth and reproduction of cariogenic microbiota due to external factors or the disruption of homeostasis by one's own factors. To reduce the occurrence of dental caries effectively, and considering the latest scientific viewpoints, caries may be viewed from the perspective of ecology, and preventive measures can be taken; hence, this article systematically summarizes the prevention and treatment of dental caries from the aspects of ecological perspectives, in particular the ecological biofilm formation, bacterial quorum sensing, the main cariogenic microbiota, and preventive measures.

In situ detection of endogenous proteolytic activity and the effect of inhibitors on tooth root surface

OBJECTIVES

The aim of this study was to clarify the distribution and activity of proteolytic enzymes and examine the inhibitory effects of various substances on this proteolytic activity on tooth root surfaces in situ.

METHODS

Disk-shaped bovine tooth root samples were partly pretreated in acid solution (50 mM lactic acid buffer, pH 4.0) for 48 h. The fluorescence intensity of samples was detected with fluorescent substrate solution for collagenase and gelatinase using a stereoscopic fluorescence microscope for 60 min. The acid-pretreated and non-acid-pretreated root samples were treated with chlorhexidine (CHX), sodium fluoride (NaF), epigallocatechin gallate (EGCG), and calcium hydroxide (Ca(OH)₂) for 10 min, and silver diamine fluoride (SDF) for 10, 30, and 60 s. These samples were immersed in the fluorescence substrate solution at pH 7.0, and the fluorescence intensity of samples was detected. The fluorescence intensity was calculated using analysis software.

RESULTS

Gelatinase activity was detected in root samples. Gelatinase activity of the acid-pretreated side was significantly higher than that of the non-acid-pretreated side (1.63 times) at 60 min. CHX, EGCG, Ca(OH)₂, and SDF decreased the gelatinase activity of root samples, while NaF had no effect.

CONCLUSIONS

Gelatinase activity was detected from the root in situ and it was increased by acid-pretreatment. CHX, EGCG, Ca(OH)₂, and SDF inhibited gelatinase activity.

CLINICAL SIGNIFICANCE

Substances that inhibit proteolytic activity found in this research method will be useful for root caries prevention.

Chronic oral diseases burden: The confluence of caries and periodontitis throughout life

AIM

To investigate the confluence of caries and periodontitis indicators from adolescence to elderhood among Americans.

MATERIALS AND METHODS

This cross-sectional study explored the grouping among a set of caries and periodontitis indicators (the proportion of sites with bleeding on probing, moderate probing pocket depth [PPD, 4-5 mm], severe PPD [≥6 mm], moderate clinical attachment level [CAL, 3-4 mm], severe CAL [≥5 mm], number of teeth with furcation involvement, number of decayed teeth, number of teeth with pulp involvement, and the number of missing teeth) in 14,421 Americans from the NHANES III study. Exploratory factorial analysis was used to determine the constructs between those indicators (factorial loading ≥0.3). These analyses were stratified by age and confirmed with a confirmatory factorial analysis. We also performed a sensitivity analysis using the NHANES 2011-2014.

RESULTS

Two constructs were extracted. The first, Chronic Oral Diseases Burden, grouped caries indicators with moderate PPD and moderate CAL for the youngest subjects (13-39 years old), while for the subjects over 50 years, the Chronic Oral Disease Burden grouped caries indicators with severe CAL and PPD and furcation involvement. The second construct, Periodontal Destruction, grouped only periodontitis indicators.

CONCLUSIONS

Caries and periodontitis indicators grouped consistently across the different age ranges in lapse times of 25 years.

Effect of Particle Sizes and Contents of Surface Pre-Reacted Glass Ionomer Filler on Mechanical Properties of Auto-Polymerizing Resin

Herein, the mechanical properties of an auto-polymerizing resin incorporated with a surface pre-reacted glass ionomer (S-PRG) filler were evaluated. For this, S-PRG fillers with particle sizes of 1 μm (S-PRG-1) and 3 μm (S-PRG-3) were mixed at 10, 20, 30, and 40 wt% to prepare experimental resin powders. The powders and a liquid (powder/liquid ratio = 1.0 g/0.5 mL) were kneaded and filled into a silicone mold to obtain rectangular specimens. The flexural strength and modulus (n = 12) were recorded via a three-point bending test. The flexural strengths of S-PRG-1 at 10 wt% (62.14 MPa) and S-PRG-3 at 10 and 20 wt% (68.68 and 62.70 MPa, respectively) were adequate (>60 MPa). The flexural modulus of the S-PRG-3-containing specimen was significantly higher than that of the S-PRG-1-containing specimen. Scanning electron microscopy observations of the specimen fracture surfaces after bending revealed that the S-PRG fillers were tightly embedded and scattered in the resin matrix. The Vickers hardness increased with an increasing filler content and size. The Vickers hardness of S-PRG-3 (14.86–15.48 HV) was higher than that of S-PRG-1 (13.48–14.97 HV). Thus, the particle size and content of the S-PRG filler affect the mechanical properties of the experimental auto-polymerizing resin.

High-Throughput Sequencing Analysis of the Changes in the Salivary Microbiota of Hungarian Young and Adult Subpopulation by an Anthocyanin Chewing Gum and Toothbrush Change

The sour cherry contains anthocyanins, which have bactericide action against some oral bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa). Sour cherry also has antibiofilm action against Streptococcus mutans, Candida albicans, and Fusobacterium nucleatum. Our earlier research proved that chewing sour cherry anthocyanin gum significantly reduces the amount of human salivary alpha-amylase and Streptococcus mutans levels. The microbiota of a toothbrush affects oral health and regular toothbrush change is recommended. A total of 20 healthy participants were selected for the study. We analysed saliva samples with 16S rRNA sequencing to investigate the effect of 2 weeks (daily three times, after main meals) of chewing sour cherry anthocyanin gum-supplemented by toothbrush change in half of our case-control study cohort-after scaling on human oral microbiota. A more stable and diverse microbiome could be observed after scaling by the anthocyanin gum. Significant differences between groups (NBR: not toothbrush changing; BR: toothbrush changing) were evaluated by log₂ proportion analysis of the most abundant family and genera. The analysis showed that lower level of some Gram-negative anaerobic (Prevotella melaninogenica, Porphyromonas pasteri, Fusobacterium nucleatum subsp. vincentii) and Gram-positive (Rothia mucilaginosa) bacteria could be observed in the case group (BR), accompanied by build-up of health-associated Streptococcal network connections.

Illuminating the oral microbiome and its host interactions: tools and approaches for molecular ecological studies

A more comprehensive understanding of oral diseases like caries and periodontitis is dependent on an intimate understanding of the microbial ecological processes that are responsible for disease development. With this review, we provide a comprehensive overview of relevant molecular ecology techniques that have played critical roles in the current understanding of human oral biofilm development, interspecies interactions, and microbiome biogeography. The primary focus is on relevant technologies and examples available in the oral microbiology literature. However, most, if not all, of the described technologies should be readily adaptable for studies of microbiomes from other mucosal sites in the body. Therefore, this review is intended to serve as a reference guide used by microbiome researchers as they inevitably transition into molecular mechanistic studies of the many significant phenotypes observed clinically.

Short-term sugar stress induces compositional changes and loss of diversity of the supragingival microbiota

Frequent intake of free sugars is a major risk factor for dental caries, but the immediate influence of sugar intake on the supragingival microbiota remains unknown. We aim to characterize the effect of 14 days of sugar rinsing on the supragingival microbiota. Forty orally and systemically healthy participants rinsed their mouth with a 10% sucrose solution, 6-8 times a day, for 14 days, followed by 14 days without sugar stress. Supragingival plaque samples were collected at baseline, and after 14, and 28 days. The supragingival microbiota was analyzed using 16S rDNA sequencing. Taxonomic classification was performed using the Human Oral Microbiome Database. After 14 days of sugar stress induced by the daily sugar rinses, a significant loss of α-diversity (p = 0.02) and a significant increase in the relative abundance of Actinomyces (6.5% to 9.6%, p = 0.006) and Corynebacterium (6.2% to 9.1%, p = 0.03) species were recorded. In addition, a significant decrease in Streptococcus (10.3% to 6.1%, p = 0.001) species was observed. Sugar-mediated changes returned to baseline conditions 14 days after the last sugar rinse. The present study shows that temporary sugar stress induces loss of diversity and compositional changes to the supragingival microbiota, which are reversible if oral care is maintained.

Meta-analysis of caries microbiome studies can improve upon disease prediction outcomes

As one of the most prevalent infective diseases worldwide, it is crucial that we not only know the constituents of the oral microbiome in dental caries but also understand its functionality. Herein, we present a reproducible meta-analysis to effectively report the key components and the associated functional signature of the oral microbiome in dental caries. Publicly available sequencing data were downloaded from online repositories and subjected to a standardized analysis pipeline before analysis. Meta-analyses identified significant differences in alpha and beta diversities of carious microbiomes when compared to healthy ones. Additionally, machine learning and receiver operator characteristic analysis showed an ability to discriminate between healthy and disease microbiomes. We identified from importance values, as derived from random forest analyses, a group of genera, notably containing Selenomonas, Aggregatibacter, Actinomyces and Treponema, which can be predictive of dental caries. Finally, we propose the most appropriate study design for investigating the microbiome of dental caries by synthesizing the studies, which had the most accurate differentiation based on random forest modelling. In conclusion, we have developed a non-biased, reproducible pipeline, which can be applied to microbiome meta-analyses of multiple diseases, but importantly we have derived from our meta-analysis a key group of organisms that can be used to identify individuals at risk of developing dental caries based on oral microbiome inhabitants.

The oral microbiota and cardiometabolic health: A comprehensive review and emerging insights

There is mounting evidence demonstrating that oral dysbiosis causes periodontal disease and promotes the development of cardiovascular disease. The advancement of omics techniques has driven the optimization of oral microbiota species analysis and has provided a deeper understanding of oral pathogenic bacteria. A bi-directional relationship exists between the oral microbiota and the host, and oral-gut microbiota transfer is known to alter the composition of the gut microbiota and may cause local metabolic disorders. Furthermore, cardiovascular health can also be highly affected by oral microbiota functions and metabolites, including short-chain fatty acids (SCFAs), nitric oxide (NO), hydrogen sulfide (H2S), and some lipid metabolites. Studies have found that trimethylamine oxide (TMAO) may have adverse effects on cardiovascular health, whereas SCFAs, NO, and H2S have cardioprotective effects. SCFAs and H2S exert varying oral and cardiovascular effects, however reports on this specific topic remain controversial. Previous evidences are accustomed to summarizing the functions of oral microbiota in the context of periodontitis. The direct relationship between oral microbiota and cardiovascular diseases is insufficient. By systematically summarizing the methods associated with oral microbiota transplantation (OMT), this review facilitates an investigation into the causal links between oral microbiota and cardiovascular disease. The concomitant development of omics, bioinformatics, bacterial culture techniques, and microbiota transplantation techniques is required to gain a deeper understanding of the relationship between oral microbiota and cardiovascular disease occurrence.

Impact of different oral treatments on the composition of the supragingival plaque microbiome

Background

Dental plaque consists of a diverse microbial community embedded in a complex structure of exopolysaccharides. Dental biofilms form a natural barrier against pathogens but lead to oral diseases in a dysbiotic state.

Objective

Using a metaproteome approach combined with a standard plaque-regrowth study, this pilot study examined the impact of different concentrations of lactoperoxidase (LPO) on early plaque formation, and active biological processes.

Design

Sixteen orally healthy subjects received four local treatments as a randomized single-blind study based on a cross-over design. Two lozenges containing components of the LPO-system in different concentrations were compared to a placebo and Listerine®. The newly formed dental plaque was analyzed by mass spectrometry (nLC-MS/MS). 

Results

On average 1,916 metaproteins per sample were identified, which could be assigned to 116 genera and 1,316 protein functions. Listerine® reduced the number of metaproteins and their relative abundance, confirming the plaque inhibiting effect. The LPO-lozenges triggered mainly higher metaprotein abundances of early and secondary colonizers as well as bacteria associated with dental health but also periodontitis. Functional information indicated plaque biofilm growth.

Conclusion

In conclusion, the mechanisms on plaque biofilm formation of Listerine® and the LPO-system containing lozenges are different. In contrast to Listerine®, the lozenges led to a higher bacterial diversity.

Free Sugar Intake and Periodontal Diseases: A Systematic Review

High free sugar intake is associated with an increased risk of various non-communicable diseases. We aimed to systematically review articles investigating the association between free sugar intake and periodontal diseases. This systematic review was conducted according to PRISMA guidelines and was registered in the PROSPERO database (CRD42022337828). We obtained articles from PubMed, Web of Science, and Scopus in April 2022. The study selection was performed according to predefined eligibility criteria based on the following PECOS: (P) general population, (E/C) free-sugar-containing food/beverage intake, (O) clinically measured periodontal diseases, and (S) observational study and clinical trial. Of the 839 screened records, 13 studies were included in the review. Most studies (n = 12) had a cross-sectional design. The age groups in the included studies were children/adolescents (n = 5) and adults (n = 8). Among the included studies, 11 reported a significant association between the frequent intake of free-sugar-containing food or beverages and a higher prevalence or incidence of periodontal diseases. The quality of most of the included studies was scored "fair" based on the Newcastle-Ottawa Quality Assessment Scale. Although the majority of the included studies reported a significant positive association between high free sugar intake and periodontal diseases, the evidence is considered to be limited due to the study designs.

Association between Four Dietary Patterns and the Risk of Periodontal Diseases: A Systematic Review and Meta-Analysis

Background: Several dietary patterns are reported as risk factors for several chronic diseases including oral diseases. However, thus far, there has been no comprehensive quantitative analysis of nutrition and periodontal diseases. Methods: This systematic review was conducted according to the PRISMA guidelines. Cohort, case–control, and cross-sectional studies were eligible for inclusion in this study. The Newcastle–Ottawa scale was used to qualitatively assess the risk of bias in the included studies. The number of samples was used for odds ratio calculation, followed by the unadjusted value and 95% confidence interval. Results: Nine papers were included for the systematic review and meta-analysis. The results of screening for database search records showed that four diet patterns (western diet, dairy product intake, sugar intake, and vitamin C intake) have enough data for meta-analysis. The risk of periodontal disease in the western-diet group and the lowest dairy product intake group was 1.05 (0.51–2.13) and 1.28 (0.89–1.84), respectively. The risk of periodontal disease in the highest sugar intake group and the lowest vitamin C intake group was 1.52 (0.79–2.91) and 1.15 (1.08–1.23), respectively. Conclusions: With aging of the population globally, the prevalence of periodontal disease increases, and the associated cost also increases. Though this study, we found foods related to the risk of periodontal disease, and we are confident that it will contribute to lowering the incidence of the disease.

Effects of sugar-free polyol chewing gums on gingival inflammation: a systematic review

OBJECTIVES

A systematic review of published data was conducted with the aim of assessing the effects of sugar-free polyol chewing gums on gingival inflammation.

MATERIALS AND METHODS

Electronic and hand searches were performed to find clinical studies concerning the effects of sugar-free chewing gums on gingival scores. Prospective randomized controlled clinical trials published between 1971 and 2021 were included in the review.

RESULTS

The initial search identified 46 erythritol, 102 xylitol, 23 sorbitol, and nine maltitol chewing gum articles. After applying inclusion and exclusion criteria, seven xylitol chewing gum studies, one sorbitol, and one maltitol chewing gum study with either high or fair quality were reviewed. In five out of the seven xylitol studies, xylitol gum decreased gingival scores. In two studies, xylitol decreased gingival scores compared to a polyol gum, and in three studies compared to no gum/gum base. As for sorbitol and maltitol, only sorbitol gum chewing showed a small decrease in gingival scores compared to the controls.

CONCLUSIONS

Habitual xylitol gum chewing may reduce gingival inflammation. The low number of studies and their heterogeneity provide clear indications that the effects of sugar-free polyol chewing gums on gingival inflammation need further, well-controlled studies.

CLINICAL RELEVANCE

Sugar-free chewing gums, especially xylitol gum, may function as adjuncts to toothbrushing for reducing gingival inflammation, but the evidence so far is inconclusive.

Continuously Quantifying Oral Chemicals Based on Flexible Hybrid Electronics for Clinical Diagnosis and Pathogenetic Study

Simultaneous monitoring of diverse salivary parameters can reveal underlying mechanisms of intraoral biological processes and offer profound insights into the evolution of oral diseases. However, conventional analytical devices with bulky volumes, rigid formats, and discrete sensing mechanisms deviate from the requirements of continuous biophysiological quantification, resulting in huge difficulty in precise clinical diagnosis and pathogenetic study. Here, we present a flexible hybrid electronic system integrated with functional nanomaterials to continuously sense Ca2+, pH, and temperature for wireless real-time oral health monitoring. The miniaturized system with an island-bridge structure that is designed specifically to fit the teeth is only 0.4 g in weight and 31.5×8.5×1.35 mm3 in dimension, allowing effective integration with customized dental braces and comfort attachment on teeth. Characterization results indicate high sensitivities of 30.3 and 60.6 mV/decade for Ca2+ and pH with low potential drifts. The system has been applied in clinical studies to conduct Ca2+ and pH mappings on carious teeth, biophysiological monitoring for up to 12 h, and outcome evaluation of dental restoration, providing quantitative data to assist in the diagnosis and understanding of oral diseases. Notably, caries risk assessment of 10 human subjects using the flexible system validates the important role of saliva buffering capacity in caries pathogenesis. The proposed flexible system may offer an open platform to carry diverse components to support both clinical diagnosis and treatment as well as fundamental research for oral diseases and induced systemic diseases.

Does high sugar intake really alter the oral microbiota?: A systematic review

OBJECTIVES

Diet is one of the main factors influencing the diversity and interactions of the oral microbiota. The purpose of this study is to determine the impact of sugar intake on the microbial diversity and bacteria that predominate under these conditions.

MATERIAL AND METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guide, using the PubMed, Scopus, and Science Direct databases and combinations of the words "microbiota," "microbiology," "bacteria," "sugars," "dysbiosis," "caries," "microbiome," "oral microbial," and "oral microbiota profile pattern." The selection criteria included year, language, type of publication, comparison of microbiota during low and high sugar intake, and bacterial identification by molecular sequencing of the 16S subunit of ribosomal RNA.

RESULTS

Out of a total of 374 papers that came up after the initial search, 8 met the criteria for this review. The papers included research on populations comprising children, young adults, and adults, with most of the studies reporting selection criteria for the participants and using validated instruments to determine sugar intake. Apart from one study, all others reported for high sugar intake conditions a significant decrease in microbial diversity of the oral microbiome and the predominance of several bacterial genera or species, including Streptococcus, Scardovia, Veillonella, Rothia, Actinomyces, and Lactobacillus.

CONCLUSIONS

Sugar-rich diets have a significantly unfavorable effect on the diversity and balance of oral microbiota; however, further studies are required to determine the exact role of sugar in microbial interactions.

Clustering of Signs and Symptoms of Oral Diseases in a Colombian Population

OBJECTIVE

The aim of this study was to estimate disease pattern clusters and co-occurrences of oral signs and symptoms in a Colombian population.

METHODS

A cross-sectional study was carried out through a telephone survey amongst 1155 people registered in the telephone directory from Pasto, Colombia. The calls were made from July to November 2019. A 14-item self-report questionnaire about signs and symptoms related to oral diseases that included sociodemographic characteristics was employed. Descriptive and multivariable analyses such as hierarchical clustering, multidimensional scaling, and generalized linear models were used to determine co-occurrences in different sex and age strata.

RESULTS

Age- and condition-specific clusters of signs and symptoms were identified, while sex differences were limited. Calculus and denture sore mouth were related in 18- to 34-year-olds; tooth loss and calculus in 35- to 54-year-olds, and teeth holes or pits (dental caries) and dental abscess in those aged 55 years and older. We found stronger associations between periodontal disease (bleeding gums) and dental caries (odds ratio [OR], 2.484; 95% confidence interval [CI], 1.812-3.405; P < .001) as well as grinding/clenching and facial tension (OR, 7.162; 95% CI, 5.227-9.814; P < .001).

CONCLUSIONS

Age-specific clustering of signs and symptoms and diagnostic patterns wer present in ths Colombian cohort.

Enrichment of sulphate-reducers and depletion of butyrate-producers may be hyperglycaemia signatures in the diabetic oral microbiome

Objectives

This study aimed to investigate oral microbial signatures associated with hyperglycaemia, by correlating the oral microbiome with three glycaemic markers. Potential association between clinical parameters and oral bacterial taxa that could be modulating the hyperglycaemic microbiome was also explored.

Methods

Twenty-three individuals diagnosed with type 2 Diabetes Mellitus (T2D) and presenting periodontitis were included, as well as 25 systemically and periodontally healthy ones. Fasting blood glucose, glycated haemoglobin, salivary glucose, periodontitis classification, caries experience and activity and salivary pH were evaluated. The V4 region of the 16S rRNA gene was amplified from total salivary DNA, and amplicons were sequenced (Illumina MiSeq).

Results

Hyperglycaemia was correlated with proportions of Treponema, Desulfobulbus, Phocaiecola and Saccharimonadaceae. Desulfobulbus was ubiquitous and the most enriched organism in T2D individuals (log2FC = 4). The Firmicutes/Bacteroidetes ratio was higher at alkali salivary pH than acidic pH. In the network analysis, Desulfobulbus was clustered in a negative association with caries-associated and butyrate-producing bacteria.

Conclusion

The salivary microbiome is shaped by systemic hyperglycaemia, as well as changes in the salivary pH, which may be linked to local hyperglycaemia. The enrichment of predictive biomarkers of gut dysbiosis in the salivary microbiome can reflect its capacity for impairment of hyperglycaemia.

Investigating oral and systemic pathways between unhealthy and healthy dietary patterns to periodontitis in adolescents: A population-based study

AIM

To investigate pathways between unhealthy and healthy dietary patterns and periodontitis in adolescents (18-19 years of age).

MATERIALS AND METHODS

This population-based study (n = 2515) modelled direct and mediated pathways (via biofilm and obesity) from patterns of healthy diet (fruits, fibre, vegetables, and dairy) and unhealthy diet (sugars, snacks, and salty/fast foods) with initial periodontitis (bleeding on probing [BoP], probing depth [PD] ≥ 4 mm, clinical attachment loss [CAL] ≥ 4 mm), moderate periodontitis (BoP, PD ≥ 5 mm, and CAL ≥ 5 mm), and European Federation of Periodontology and the American Academy of Periodontology (EFP-AAP) periodontitis definitions, adjusting for sex, socio-economic status, smoking, and alcohol, through structural equation modelling (α = 5%).

RESULTS

Higher values of healthy diet were associated with lower values of initial periodontitis (standardized coefficient [SC] = -0.160; p < .001), moderate periodontitis (SC = -0.202; p < .001), and EFP-AAP periodontitis (p < .05). A higher value of unhealthy diet was associated with higher values of initial periodontitis (SC = 0.134; p = .005) and moderate periodontitis (SC = 0.180; p < .001). Biofilm mediated the association between higher values of unhealthy diet and all periodontal outcomes (p < .05).

CONCLUSIONS

Our findings suggest that both healthy and unhealthy dietary patterns may contribute to reduced or increased extent and severity of periodontitis by local and systemic mechanisms, preceding the effect of other established causes such as smoking and obesity, in younger population.

Evidence on the Use of Mouthwash for the Control of Supragingival Biofilm and Its Potential Adverse Effects

Antimicrobial mouthwash improves supragingival biofilm control when used in conjunction with mechanical removal as part of an oral hygiene routine. Mouthwash is intended to suppress bacterial adhesion during biofilm formation processes and is not aimed at mature biofilms. The most common evidence-based effects of mouthwash on the subgingival biofilm include the inhibition of biofilm accumulation and its anti-gingivitis property, followed by its cariostatic activities. There has been no significant change in the strength of the evidence over the last decade. A strategy for biofilm control that relies on the elimination of bacteria may cause a variety of side effects. The exposure of mature oral biofilms to mouthwash is associated with several possible adverse reactions, such as the emergence of resistant strains, the effects of the residual structure, enhanced pathogenicity following retarded penetration, and ecological changes to the microbiota. These concerns require further elucidation. This review aims to reconfirm the intended effects of mouthwash on oral biofilm control by summarizing systematic reviews from the last decade and to discuss the limitations of mouthwash and potential adverse reactions to its use. In the future, the strategy for oral biofilm control may shift to reducing the biofilm by detaching it or modulating its quality, rather than eliminating it, to preserve the benefits of the normal resident oral microflora.

Polymicrobial biofilms related to dental implant diseases: unravelling the critical role of extracellular biofilm matrix

Biofilms are complex tri-dimensional structures that encase microbial cells in an extracellular matrix comprising self-produced polymeric substances. The matrix rich in extracellular polymeric substance (EPS) contributes to the unique features of biofilm lifestyle and structure, enhancing microbial accretion, biofilm virulence, and antimicrobial resistance. The role of the EPS matrix of biofilms growing on biotic surfaces, especially dental surfaces, is largely unravelled. To date, there is a lack of a broad overview of existing literature concerning the relationship between the EPS matrix and the dental implant environment and its role in implant-related infections. Here, we discuss recent advances in the critical role of the EPS matrix on biofilm growth and virulence on the dental implant surface and its effect on the etiopathogenesis and progression of implant-related infections. Similar to other biofilms associated with human diseases/conditions, EPS-enriched biofilms on implant surfaces promote microbial accumulation, microbiological shift, cross-kingdom interaction, antimicrobial resistance, biofilm virulence, and, consequently, peri-implant tissue damage. But intriguingly, the protagonism of EPS role on implant-related infections and the development of matrix-target therapeutic strategies has been neglected. Finally, we highlight the need for more in-depth analyses of polymicrobial interactions within EPS matrix and EPS-targeting technologies' rationale for disrupting the complex biofilm microenvironment with more outstanding translation to implant applications in the near future.

Child saliva microbiota and caries: a randomized controlled maternal education trial in rural Uganda

Undernutrition is a public health challenge in sub-Saharan countries, including Uganda. In a previous randomized controlled trial (RCT) with a nutrition, hygiene and stimulation education intervention among mothers of 6 months’ old children, we found less caries in the intervention group when the children were 36 months of age. We now examined the effects of (i) the intervention on the microbiota, (ii) microbiota on caries, and (iii) the intervention and microbiota on caries. The original RCT comprised 511 mother/child pairs whereas in the current study we had access to data from 344/511 (67%) children aged 36 months. The saliva microbiota was determined using 16S rRNA gene sequencing. Carious lesions (a proxy for dental health) were identified using close-up intra-oral photographs of the upper front teeth. Statistical models were used to determine host-microbiota associations. The intervention had a significant effect on the microbiota, e.g. an increase in Streptococcus abundance and decreases in Alloprevotella and Tannerella. Significant associations between the microbiota and dental caries were identified: Positive associations of Capnocytophaga and Tannerella suggest that these taxa may be deleterious to dental health while negative associations of Granulicatella, Fusobacterium, and Abiotrophia suggest taxa potentially beneficial or benign contributors to dental health. Based on taxonomic profiles, the effects of the intervention and microbiota on dental health may be independent of one another. Educational interventions with emphasis on nutrition and oral hygiene may provide a feasible strategy to decrease progression of childhood caries in low-resource settings.