Maintaining the integrity of the enamel surface

Dental caries and periodontal disease among people who use drugs: a systematic review and meta-analysis

BACKGROUND

The aim of our study was to perform a systematic review of the literature and meta-analysis in order to investigate relationship between drug use and oral health.

METHODS

We searched for studies in English published before July 1, 2019 on PsycINFO, PubMed, SciELO, Scopus, and Web of Science. We assessed the relationship between drug use (methamphetamines, heroin; opiates; crack, cocaine and cannabis as dependent variables) and reported tooth loss, periodontal disease, or decayed, missing, and filled teeth index as an independent variable. The data were analyzed using Stata 12.0 software.

RESULTS

We initially identified 1836 potential articles (with 1100 duplicates) and screened the remaining 736 titles and abstracts, comprising 54 studies. In the next step, we evaluated the full-texts; 44 studies were excluded, accordingly. In total, we included 10 publications in the meta-analysis. Drug type was associated with periodontal disease (OR 1.44; 95% CI 0.8-2.6) and pooled estimates showed that type of drug used increased the odds of the number of decayed, missed and filled teeth (DMFT) (OR 4.11; 95% CI 2.07-8.15) respectively.

CONCLUSIONS

The analytical challenges of segregating the impact of individual drug types on oral health diseases mean that investigations on the direct relationship between oral health status and drug use are limited. Developing programs to improve potential confounding with various substances and addressing the dental health needs of people who use drugs is vital if we are to improve their overall quality of life.

Fluorinated Montmorillonite and 3YSZ as the Inorganic Fillers in Fluoride-Releasing and Rechargeable Dental Composition Resin

Dental caries (tooth decay) is the most frequent oral disease in humans. Filling cavities with a dental restorative material is the most common treatment, and glass ionomer cements are the main fluoride ion release restorative materials. The goal of this study was to develop a restorative compound with superior fluoride ion release and recharge abilities. Previously developed fluorinated bentolite and hydrophobized 3YSZ were used as two different inorganic fillers mixed in a bisphenol A-glycidyl methacrylate (Bis-GMA) matrix. XRD, FTIR, and TGA were used to determine the hydrophobic modification of these two inorganic fillers. In mechanical tests, including diameter tensile strength, flexural strength, and wear resistance, the developed composite resin was significantly superior to the commercial control. A WST-1 assay was used to confirm that the material displayed good biocompatibility. Furthermore, the simulation of the oral environment confirmed that the composite resin had good fluoride ion release and reloading abilities. Thus, the composite resin developed in this study may reduce secondary caries and provide a new choice for future clinical treatments.

Making sense of medieval mouths: Investigating sex differences of dental pathological lesions in a late medieval Italian community

OBJECTIVES

Bioarchaeological investigations of sex-based differences in the prevalence of dental pathological lesions, particularly caries, have drawn considerable attention, and out of this work, two dominant models have emerged. Traditionally, the first model interprets sex-related patterns in caries as a product of gendered differences in diet. A more recent model interprets a generally higher propensity for caries prevalence in females in light of reproductive ecology. To test the hypothesis that females have higher risk of caries in accordance with reproductive ecology, we examined and analyzed caries prevalence and other potentially synergistic oral pathological lesions in a late medieval (A.D. 1300-1500) Italian archaeological sample.

MATERIALS AND METHODS

We examined sex- and age-related prevalence in caries and other oral pathological lesions in a late medieval Italian skeletal assemblage excavated from Villamagna consisting of 38 females and 37 males (n = 1,534 teeth). We examined age- and sex-related patterns in six dental traits: antemortem tooth loss, caries, calculus, periapical inflammation, tooth wear, and periodontitis.

RESULTS

Significant age-related increases in antemortem tooth loss, caries, calculus, and tooth wear were observed in both males and females. However, there was a lack of expected sex differences in oral pathological lesions, with instead older males exhibiting significantly more antemortem tooth loss and corrected caries than females.

DISCUSSION

Results are discussed in relation to the ethnohistoric context of medieval rural dietary practices as well as biomedical salivary literature, which suggest that dietary changes throughout the life course may have facilitated trade-offs that buffered females from higher rates of dental pathological lesions.

Oral health and behaviours of people living with Multiple Sclerosis in Australia

OBJECTIVES

The literature describing the oral health of people with Multiple Sclerosis (MS) is scant and the findings equivocal. The aim of this study was to describe the oral health and oral self-care behaviours of people living with MS and compare it to the Australian population.

METHODS

Participants enrolled with the Australian MS Longitudinal Study (AMSLS) were invited to participate in the survey using an online or paper-based questionnaire. Data were collected on level of disability, oral health, oral self-care and factors influencing attendance for oral health care.

RESULTS

Completed questionnaires were received for 1523 respondents. Over one-fifth (n = 320; 22%) rated their oral health as fair or poor, and more than half (n = 840; 57%) reported toothache in the last 12 months. These proportions were higher than those for the general Australian adult population (oral health prevalence ratio (PR) = 1.25 [1.12, 1.40]; toothache PR = 3.63 [3.39, 3.88]), and this is despite comparable or better self-maintenance habits and dental attendance reported by respondents. People with MS reported high rates of mouth dryness (68.4%), teeth sensitivity (64.7%), change of taste (40.5%) and orofacial pain (39.0%); fewer than 10% experienced none of these. There was a lower prevalence of self-reported need for treatment (extraction or filling) than in the Australian adult population (15.8% vs 32.9%).

CONCLUSIONS

People with MS have a greater oral health burden, demonstrated by their poorer self-reported oral health than the Australian adult population. Furthermore, they experience high rates of toothache, mouth dryness, teeth sensitivity, change of taste and orofacial pain. These findings are contrary to their self-reported good oral self-care and dental attendance habits and suggest some of the oral health impacts are due to MS rather than dental behaviours.

Conservative Management of Dental Erosion in Adolescents with Medical Conditions

The prevalence of dental erosion among children and adolescents is trending higher in recent decades and is becoming a major concern. Dental erosion can be caused by either extrinsic or intrinsic acids or both. One of the established aetiological factors for dental erosion by intrinsic acid is the gastrooesophageal reflux disease. The degree of dental erosions may be influenced by any medical conditions that cause a reduction in salivary flow such as the salivary gland excision, autoimmune disease, radiation to the head and neck regions, and medications. If left untreated, the dental erosion can cause dentine hypersensitivity, loss of occlusal vertical height, and aesthetic problems. For effective management of dental erosion, the aetiology of each case must be determined, and its detection at an early stage is of prime importance. This case report illustrates the conservative management of dental erosion in two adolescent patients presented with their medical conditions and behaviour issues. The aim of the treatments was to preserve the vitality of the affected teeth. The treatments were successfully completed using a conservative approach, with the patients' medical conditions taken into consideration.

Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

Introduction:

Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion.

Methods:

Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test.

Results:

Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05).

Conclusion:

Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

A Review of Selected Studies That Determine the Physical and Chemical Properties of Saliva in the Field of Dental Treatment

Physiological whole saliva is a unique body fluid constantly washing the mucous membranes of the mouth, throat, and larynx. Saliva is a clear, slightly acidic mucinous-serous secretion, composed of various electrolytes, small organic substances, proteins, peptides, and polynucleotides. There are many ways to use saliva as a biological fluid (biofluid). The significant advantages of saliva as a unique diagnostic material are its availability and the noninvasive method of collection. The aim of this review is to emphasize the diagnostic value of saliva as a research material in the configuration of its structure and secretion disorders. The data were obtained using the MEDLINE (PubMed) search engine, as well as an additional manual search. The analysis covered 77 articles selected from a group of 1986 publications and initially qualified for devising. The results were evaluated and checked for the correctness of qualifying in accordance with inclusion and exclusion criteria. The diagnostic use of saliva has attracted the attention of many researchers due to its noninvasive nature and relative simplicity of collection. In addition, it should be noted that the determination of chemical and physical saliva parameters can be effectively performed in the patient's presence in the dental office.

[Increased oral fluid remineraling function by endogenous and exogenous saturation methods of its mineral complexes]

RELEVANCE

One of the most common problems in modern caries prevention is the development of techniques to increase tooth resistance to the effects of cariogenic factors. Therefore, research is needed to study the chemical composition of tissues like teeth and body fluids surrounding the tooth to prevent demineralization process. The purpose of determining the effectiveness of work- and correlation relationship between endo saturation exogenous methods oral liquid mineral complexes.

MATERIAL AND METHODS

In 95 patients analyzed the chemical composition and structure of the oral fluid by IR spectroscopy. For the collection of IR spectra used Verteh-70 spectrometer ('Bruker', Germany) and the prefix of frustrated total internal reflection PLATINUM ATR diamond prism.

RESULTS AND DISCUSSION

A correlation between the use of endogenous and exogenous methods of caries prevention, in favor of the former, as well as changes in the mineral-organic and phosphate-carbon ratio in the dry residues of oral fluid.

The effect of parotid gland-sparing intensity-modulated radiotherapy on salivary composition, flow rate and xerostomia measures

OBJECTIVES

To describe parotid gland (PG) saliva organic and inorganic composition and flow rate changes, after curative intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC), and analyse the relationship between PG saliva analytes and xerostomia measures.

METHODS AND MATERIALS

Twenty-six patients recruited to five prospective phase 2 or 3 trials which assessed toxicity and efficacy of IMRT by HNC subsite, provided longitudinal PG saliva. Salivary flow rate, and subjective and objective xerostomia measures were prospectively collected and saliva tested for inorganic and organic analytes. Statistical comparisons of longitudinal analyte changes and analysis for a relationship between dichotomized xerostomia score and saliva analytes were performed.

RESULTS

One hundred and forty-two PG saliva samples from 26 patients were analysed. At 3-6 months after IMRT, stimulated and unstimulated saliva showed significantly decreased flow rate, total protein (TP) secretion rate, phosphate concentration and increased lactoferrin (LF) concentration. Stimulated saliva alone had elevated LF secretion rate and beta-2-microglobulin (B₂ M) concentration with decreased calcium (Ca²⁺ ) and magnesium (Mg²⁺ ) concentrations and Ca²⁺ secretion rate. At >12 months, under stimulated and unstimulated conditions, increased LF concentration and decreased Mg²⁺ and phosphate concentration persisted and, in stimulated saliva, there was decreased potassium (K⁺ ) and Mg²⁺ concentration. Unstimulated TP secretion rate was lower in the presence of high-grade xerostomia. Otherwise, no relationship between xerostomia grade and PG salivary flow rate, TP and Ca²⁺ secretion rate was found.

CONCLUSION

Fewer significant differences in PG saliva analytes >12 months after IMRT indicate good functional recovery. Residual xerostomia after IMRT will only be further reduced by addressing the sparing of subsites of the PG or other salivary gland tissues, in addition to the PG.

Managing the oral side-effects of medications used to treat multiple sclerosis

BACKGROUND

Many medications used to manage multiple sclerosis (MS) affect oral health. This review aimed to identify the oral side-effects of the current drugs recommended in Australia to treat MS and make dental practitioners aware of the range of symptoms.

METHODS

The Australian Therapeutic Guidelines and the Australian Medicines Handbook were searched for medications used to treat MS. For each medication, the generic name, class, route of administration, dosage and drug company reported side-effects were extracted from the online Monthly Index of Medical Specialties (MIMs) database. Meyler's Side-effect of Drugs Encyclopaedia was used to identify any additional oral adverse reactions to medications used to treat MS.

RESULTS

Fourteen drugs were identified for the treatment of MS progression and 13 drugs for the treatment of MS symptoms. For these medications, 18 oral side-effects were documented: xerostomia was the most common, followed by dysgeusia, dysphagia, mouth ulceration and sinusitis. Anticholinergic drugs caused xerostomia while immunosuppressants resulted in more infection-related side-effects.

CONCLUSIONS

Dental practitioners should be aware of the range of symptoms likely to be reported by this population. Clinicians are encouraged to continue providing dental care for their patients who develop MS and refer complex cases to specialists.

Changes in white spot lesions following post-orthodontic weekly application of 1.25 per cent fluoride gel over 6 months-a randomized placebo-controlled clinical trial. Part II: clinical data evaluation

Background

White spot lesions (WSL) frequently occur as side-effect of multibracket appliance treatment. The clinical effects of local fluoridation on post-orthodontic WSL and oral health development are however inconclusive.

Objective

In vivo monitoring of clinical WSL and oral health changes in response to weekly 1.25 per cent fluoride gel application after multibracket appliance treatment.

Trial design

Randomized, single-centre, double-blind, parallel-group, placebo-controlled study.

Participants

Patients with not less than 1 WSL (modified score 1 or 2) on not less than 1 upper front teeth after debonding.

Interventions

Professional fluoride/placebo gel application during weeks 1-2; self-administered home application (weeks 3-24).

Outcomes

Clinical evaluation of WSL index, lesion activity, plaque index, gingival bleeding index, and decayed, missing, and filled teeth index as well as saliva buffer capacity and stimulated salivary flow rate (T0-T5).

Randomization

Random assignment to test (n = 23) or placebo group (n = 23) using a sequentially numbered list (random allocation sequence generated for 50 subjects in 25 blocks of 2 subjects each).

Recruitment

The clinical study duration lasted from March 2011 to September 2013.

Blinding

Unblinding was performed after complete data evaluation.

Numbers analysed

Intention-to-treat analysis set comprised 39 participants (test: n = 21, placebo: n = 18).

Outcome

No clinical parameter except stimulated salivary flow rate (fluoride group: 1.1ml/min, placebo group: 0.74ml/min; P = 0.022) showed a statistically significant group difference after 24 weeks.

Harms

Several adverse events occurred similarly frequent in both groups; none was classified as possibly related to the study product.

Limitations

The number of dropouts was higher than expected and the socio-economic status was not assessed. Furthermore, the unknown level of compliance during the home application phase must be considered as limitation.

Conclusion

Based on the results of this study, no clinical effect of post-orthodontic high-dose fluoride treatment on WSL and oral health changes could be detected.

Registration

The study was registered with ClinicalTrials.gov (Identifier: NCT01329731).

Protocol

The protocol wasn't published before trial commencement.

Nutritional Correlates of Human Oral Microbiome

BACKGROUND

Despite many potential effects of the oral microbiome on oral and systemic health, scant information is available regarding the associations between diet and the oral microbiome.

METHODS

Oral rinse DNA samples from 182 participants in a population-based case-control study for colorectal cancer were used to amplify a V3-V4 region of bacterial 16S rRNA gene. The amplicons were sequenced using Illumina MiSeq paired end chemistry on 2 runs, yielding approximately 33 million filtered reads that were assigned to bacterial classes. Relative abundances of each class and family as well microbial diversity/richness indices were correlated with selected dietary intakes from a food frequency questionnaire.

RESULTS

Saturated fatty acids (SFAs) and vitamin C intakes were consistently correlated with alpha (within-subjects) diversity indexes in both richness and diversity. SFA intake was positively correlated with relative abundance of betaproteobacteria and fusobacteria. Vitamin C and other vitamins with correlated intakes-for example, the B vitamins and vitamin E-exhibited positive correlations with fusobacteria class, its family Leptotrichiaceae and a clostridia family Lachnospiraceae. In addition, glycemic load was positively correlated with Lactobacillaceae abundance.

CONCLUSION

The observed associations in this study were modest. However, the results suggest that the effects of diets are likely to be habitat specific, and observations from the gut microbiome are not transferrable to the oral microbiome. Further studies are warranted, incorporating a range of host biomarkers, such as cytohistological, molecular, or biochemical measurements, in order to address biological consequences of these dietary intakes in human oral health.

Salivary Diagnostics-Point-of-Care diagnostics of MMP-8 in dentistry and medicine

Human saliva is an easily accessible biological fluid and contains a variety of disease-related biomarkers, which makes it a potential diagnostic medium. The clinical use of salivary/oral fluid biomarkers to identify oral and systemic conditions requires the development of non-invasive screening and diagnostic technologies, and is among the main goals of oral fluid researchers. The analysis of the disease-specific oral and systemic biomarkers in saliva and oral fluids (i.e., mouth-rinse, gingival crevicular fluid (GCF) and peri-implantitis sulcular fluid (PISF)) is demanding. Several factors influence their expression and release; these factors include the intracellular location, the molecular size and the flow characteristics of the biological fluid. The type of saliva/oral fluid utilized for the diagnostics affects the analysis. High sensitivity together with sophisticated methods and techniques are essential to get a useful outcome. We describe here a recently developed mouth-rinse that is practical, convenient and inexpensive, as well as PISF chair-side/point of care (PoC) lateral-flow active matrix metalloproteinase (aMMP-8) immunoassays to detect, predict and monitor the course and treatment of periodontitis and peri-implantitis.

Comparative evaluation of remineralizing potential of Fluoride using three different remineralizing protocols: An in vitro study

Background:

Remineralization of noncavitated enamel is dependent on the bioavailability of calcium, phosphate, and hydroxyl ions in saliva. However, it is enhanced by the presence of fluoride. This study compared the remineralizing potential of three different topical fluoride agents.

Materials and Methods:

Fifteen extracted premolars were selected for the study. The crown of each tooth was longitudinally sectioned buccolingually and mesiodistally using a diamond disc so as to obtain sixty specimens which were embedded in acrylic molds. The specimens were immersed in demineralizing solution for 3 days. The specimens were randomly assigned to four groups, namely Duraphat fluoride varnish, ReminPro paste, ClinPro Tooth Crème, and control group (no surface treatment). A pH cycling includes alternate demineralization and remineralization. Surface mean hardness (SMH) was recorded with 50 g load for 5 s using VHN machine at baseline, after demineralization and pH cycling. The four groups were compared for difference in SMH using one-way ANOVA followed by Tukey–Kramer test. All testing was done with alpha 0.05.

Results:

SMH recovery results for ClinPro, Duraphat, and ReminPro were 54.88%, 43.42%, and 26.86%, respectively. The difference in the percentage SMH recovery for ClinPro paste was better than Duraphat and ReminPro, and this difference was statistically significant (P < 0.05).

Conclusions:

ClinPro tooth Crème showed the best remineralization potential among the three materials tested followed by Duraphat and ReminPro.

Oral health effects, brushing habits and management of methamphetamine users for the general dental practitioner

BACKGROUND

Methamphetamine is a synthetic drug commonly abused in South Africa and is highly addictive. Users have a higher prevalence of dental caries compared to non-users and the classical caries pattern found in methamphetamine users is termed 'meth mouth'. The increased consumption of soft drinks and the absence of saliva are the main risk factors for 'meth mouth'.

AIM

To determine the oral health status of individuals using methamphetamine.

METHOD

A cross-sectional study was conducted on a convenience sample of 308 self-reported methamphetamine users at 22 specialised substance addiction treatment centres in the Western Cape, South Africa.

RESULTS

There was a significant difference in tooth brushing frequency when using methamphetamine (p = 0.0000022; χ(2) = 23.84; OR = 3.25). The mean decayed, missing and filled teeth score was ten and there was an association between the mean number of decayed teeth and the duration of drug addiction (p = 0.0071; χ(2) = 12.07). Users who were using methamphetamine for less than four years had fewer missing teeth compared to those who were using methamphetamine for more than four years.

CONCLUSIONS

When methamphetamine abuse is detected, the dentist can play a key role in early management of drug addiction by referring the patient to specialised substance addiction treatment centres. In addition, by restoring the dental appearance, users may regain their self-esteem and improve their oral health quality of life.

Saliva diagnostics - Current views and directions

In this review, we provide an update on the current and future applications of saliva for diagnostic purposes. There are many advantages of using saliva as a biofluid. Its collection is fast, easy, inexpensive, and non-invasive. In addition, saliva, as a "mirror of the body," can reflect the physiological and pathological state of the body. Therefore, it serves as a diagnostic and monitoring tool in many fields of science such as medicine, dentistry, and pharmacotherapy. Introduced in 2008, the term "Salivaomics" aimed to highlight the rapid development of knowledge about various "omics" constituents of saliva, including: proteome, transcriptome, micro-RNA, metabolome, and microbiome. In the last few years, researchers have developed new technologies and validated a wide range of salivary biomarkers that will soon make the use of saliva a clinical reality. However, a great need still exists for convenient and accurate point-of-care devices that can serve as a non-invasive diagnostic tool. In addition, there is an urgent need to decipher the scientific rationale and mechanisms that convey systemic diseases to saliva. Another promising technology called liquid biopsy enables detection of circulating tumor cells (CTCs) and fragments of tumor DNA in saliva, thus enabling non-invasive early detection of various cancers. The newly developed technology-electric field-induced release and measurement (EFIRM) provides near perfect detection of actionable mutations in lung cancer patients. These recent advances widened the salivary diagnostic approach from the oral cavity to the whole physiological system, and thus point towards a promising future of salivary diagnostics for personalized individual medicine applications including clinical decisions and post-treatment outcome predictions. Impact statement The purpose of this mini-review is to make an update about the present and future applications of saliva as a diagnostic biofluid in many fields of science such as dentistry, medicine and pharmacotherapy. Using saliva as a fluid for diagnostic purposes would be a huge breakthrough for both patients and healthcare providers since saliva collection is easy, non-invasive and inexpensive. We will go through the current main diagnostic applications of saliva, and provide a highlight on the emerging, newly developing technologies and tools for cancer screening, detection and monitoring.

Effects of CO2 laser irradiation on matrix-rich biofilm development formation-an in vitro study

BACKGROUND

A carbon dioxide (CO₂) laser has been used to morphologically and chemically modify the dental enamel surface as well as to make it more resistant to demineralization. Despite a variety of experiments demonstrating the inhibitory effect of a CO₂ laser in reduce enamel demineralization, little is known about the effect of surface irradiated on bacterial growth. Thus, this in vitro study was preformed to evaluate the biofilm formation on enamel previously irradiated with a CO₂ laser (λ = 10.6 µM).

METHODS

For this in vitro study, 96 specimens of bovine enamel were employed, which were divided into two groups (n = 48): 1) Control-non-irradiated surface and 2) Irradiated enamel surface. Biofilms were grown on the enamel specimens by one, three and five days under intermittent cariogenic condition in the irradiated and non-irradiated surface. In each assessment time, the biofilm were evaluated by dry weigh, counting the number of viable colonies and, in fifth day, were evaluated by polysaccharides analysis, quantitative real time Polymerase Chain Reaction (PCR) as well as by contact angle. In addition, the morphology of biofilms was characterized by fluorescence microscopy and field emission scanning electron microscopy (FESEM). Initially, the assumptions of equal variances and normal distribution of errors were conferred and the results are analyzed statistically by t-test and Mann Whitney test.

RESULTS

The mean of log CFU/mL obtained for the one-day biofilm evaluation showed that there is statistical difference between the experimental groups. When biofilms were exposed to the CO₂ laser, CFU/mL and CFU/dry weight in three day was reduced significantly compared with control group. The difference in the genes expression (Glucosyltransferases (gtfB) and Glucan-binding protein (gbpB)) and polysaccharides was not statically significant. Contact angle was increased relative to control when the surface was irradiated with the CO₂ laser. Similar morphology was also visible with both treatments; however, the irradiated group revealed evidence of melting and fusion in the specimens.

CONCLUSION

In conclusion, CO₂ laser irradiation modifies the energy surface and disrupts the initial biofilm formation.

Removal of Dental Biofilms with an Ultrasonically Activated Water Stream

Acidogenic bacteria within dental plaque biofilms are the causative agents of caries. Consequently, maintenance of a healthy oral environment with efficient biofilm removal strategies is important to limit caries, as well as halt progression to gingivitis and periodontitis. Recently, a novel cleaning device has been described using an ultrasonically activated stream (UAS) to generate a cavitation cloud of bubbles in a freely flowing water stream that has demonstrated the capacity to be effective at biofilm removal. In this study, UAS was evaluated for its ability to remove biofilms of the cariogenic pathogen Streptococcus mutans UA159, as well as Actinomyces naeslundii ATCC 12104 and Streptococcus oralis ATCC 9811, grown on machine-etched glass slides to generate a reproducible complex surface and artificial teeth from a typodont training model. Biofilm removal was assessed both visually and microscopically using high-speed videography, confocal scanning laser microscopy (CSLM), and scanning electron microscopy (SEM). Analysis by CSLM demonstrated a statistically significant 99.9% removal of S. mutans biofilms exposed to the UAS for 10 s, relative to both untreated control biofilms and biofilms exposed to the water stream alone without ultrasonic activation ( P < 0.05). The water stream alone showed no statistically significant difference in removal compared with the untreated control ( P = 0.24). High-speed videography demonstrated a rapid rate (151 mm2 in 1 s) of biofilm removal. The UAS was also highly effective at S. mutans, A. naeslundii, and S. oralis biofilm removal from machine-etched glass and S. mutans from typodont surfaces with complex topography. Consequently, UAS technology represents a potentially effective method for biofilm removal and improved oral hygiene.

Exploring some aspects associated with dentine hypersensitivity in children

BACKGROUND

The etiology of dentine hypersensitivity (DH) is still inconclusive and there are few studies concerning it in children.

AIM

To evaluate clinical, dietary, and salivary variables in children with DH complaints.

DESIGN

Forty-eight children were asked about DH. Data regarding dietary habits were collected from the children's parents and an examination was performed to determine dental erosion. Dental biofilm was estimated by oral hygiene status, according to Greene and Vermillion's Simplified Oral Hygiene Index (OHI-S). Whole saliva was collected under mechanical stimulation and evaluated salivary flow rate, initial pH, buffer capacity, and calcium and phosphate concentrations. The temperature of soft drinks, drinking method, sense of bitter taste, and other variables were also determined. Possible factors associated with DH were analyzed by univariate and multiple Poisson regression analyses. The prevalence ratio (PR) values and 95% confidence intervals (95% CI) were calculated.

RESULTS

DH was associated with the presence of dental erosion (PR; 95% CI = 2.23; 1.05 to 4.71) and salivary flow rate (2.49; 1.05 to 5.91). When the presence of erosion was not included, other variables were retained as follows: bitter taste (2.36; 1.38 to 4.03), OHI-S (0.47; 0.23 to 0.97).

CONCLUSION

DH in children is associated with factors related to dental erosion.

Enamel Hypomineralization and Structural Defects in Amelotin-deficient Mice

Amelotin (AMTN) is a relatively recently discovered enamel protein that is predominantly expressed by ameloblasts during the maturation stage of amelogenesis and is present at lower levels in the junctional epithelium of erupted teeth. Previous studies have suggested a function of this protein in enamel mineralization and cell attachment. Genetic mouse models have been instrumental in defining the role of many enamel-related proteins, but a genetic mouse model lacking the Amtn gene has not been reported. Here, we describe the generation of amelotin-deficient mice and the analysis of their enamel phenotype in comparison with that of wild-type animals. Ablation of AMTN expression resulted in mechanically inferior enamel of mandibular incisors that showed chipping and fractures at the incisal edge. Enamel mineralization was delayed, resulting in hypomineralized inner enamel and structural defects in the outer enamel. Erupted enamel close to the gingival margin showed increased surface roughness. The expression levels of the enamel matrix proteins AMEL, AMBN, ENAM, and ODAM and the enamel proteases MMP-20 and KLK-4 were not significantly altered, although the expression of KLK-4 was delayed. The morphology of ameloblasts showing prominent Tomes' processes during the secretory stage was not altered, and there was no indication of disruption of cell structures or activities, but a residual layer, presumably consisting of organic material, remained at the enamel surface close to the gingival margin. The integrity of the dentogingival attachment at the junctional epithelium appeared unaffected by AMTN deficiency. These observations indicate that AMTN plays a subtle yet critical role in enamel biomineralization, particularly during the establishment of the outer and surface enamel layers. This role appears to be largely independent of other enamel proteins.

Structural and mechanical repair of diffuse damage in cortical bone in vivo

Physiological wear and tear causes bone microdamage at several hierarchical levels, and these have different biological consequences. Bone remodeling is widely held to be the mechanism by which bone microdamage is repaired. However, recent studies showed that unlike typical linear microcracks, small crack damage, the clusters of submicron-sized matrix cracks also known as diffuse damage (Dif.Dx), does not activate remodeling. Thus, the fate of diffuse damage in vivo is not known. To examine this, we induced selectively Dif.Dx in rat ulnae in vivo by using end-load ulnar bending creep model. Changes in damage content were assessed by histomorphometry and mechanical testing immediately after loading (ie, acute loaded) or at 14 days after damage induction (ie, survival ulnae). Dif.Dx area was markedly reduced over the 14-day survival period after loading (p < 0.02). We did not observe any intracortical resorption, and there was no increase in cortical bone area in survival ulnae. The reduction in whole bone stiffness in acute loaded ulnae was restored to baseline levels in survival ulnae (p > 0.6). Microindentation studies showed that Dif.Dx caused a highly localized reduction in elastic modulus in diffuse damage regions of the ulnar cortex. Moduli in these previously damaged bone areas were restored to control values by 14 days after loading. Our current findings indicate that small crack damage in bone can be repaired without bone remodeling, and they suggest that alternative repair mechanisms exist in bone to deal with submicron-sized matrix cracks. Those mechanisms are currently unknown and further investigations are needed to elucidate the mechanisms by which this direct repair occurs.

Common dental and periodontal diseases: evaluation and management

Physicians may encounter patients with dental and periodontal diseases in the context of outpatient medical practice. It is important for physicians to be aware of common dental and periodontal conditions and be able to assess for the presence and severity of these diseases. This article reviews common dental and periodontal conditions, their cardinal signs and symptoms, outpatient-setting assessment techniques, as well as common methods of treatment. Physicians detecting gross abnormalities on clinical examination should refer the patient to a dentist for further evaluation and management.

Physiology of aging of older adults: systemic and oral health considerations

This article reviews the concepts of physiologic reserve, the principles of the normative aging process as exemplified by the cardiovascular, neurologic, and musculoskeletal systems. How these principles apply to oral health, and age-related changes in the oral cavity itself, is reviewed and suggests how they may affect disease management by oral health care providers. It does not focus on diseases related to aging, but rather aims to explore the normal physiologic changes associated with aging dentition and systemic changes related to age, thus enabling clinicians to obtain a better understanding of the presentation of older adults and how it may change their approach to diagnosis and treatment.

Hydrophilicity of dentin bonding systems influences in vitro Streptococcus mutans biofilm formation

OBJECTIVE

To evaluate in vitro Streptococcus mutans (S. mutans) biofilm formation on the surface of five light-curing experimental dental bonding systems (DBS) with increasing hydrophilicity. The null hypothesis tested was that resin chemical composition and hydrophilicity does not affect S. mutans biofilm formation.

METHODS

Five light-curing versions of experimental resin blends with increasing hydrophilicity were investigated (R1, R2, R3, R4 and R5). R1 and R2 contained ethoxylated BisGMA/TEGDMA or BisGMA/TEGDMA, respectively, and were very hydrophobic, were representative of pit-and-fissure bonding agents. R3 was representative of a typical two-step etch-and-rinse adhesive, while R4 and R5 were very hydrophilic resins analogous to self-etching adhesives. Twenty-eight disks were prepared for each resin blend. After a 24h-incubation at 37°C, a multilayer monospecific biofilm of S. mutans was obtained on the surface of each disk. The adherent biomass was determined using the MTT assay and evaluated morphologically with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM).

RESULTS

R2 and R3 surfaces showed the highest biofilm formation while R1 and R4 showed a similar intermediate biofilm formation. R5 was more hydrophilic and acidic and was significantly less colonized than all the other resins. A significant quadratic relationship between biofilm formation and hydrophilicity of the resin blends was found. CLSM and SEM evaluation confirmed MTT assay results.

CONCLUSIONS

The null hypothesis was rejected since S. mutans biofilm formation was influenced by hydrophilicity, surface acidity and chemical composition of the experimental resins. Further studies using a bioreactor are needed to confirm the results and clarify the role of the single factors.

An innovative approach to treating dental decay in children. A new anti-caries agent

The aim of this work is to evaluate the antimicrobial and cytotoxic activity of a formulation containing silver nanoparticles and chitosan, provisionally called nano silver fluoride (NSF), against Streptococcus mutans in comparison to chlorhexidine and silver diamine fluoride (SDF). The product was characterised by transmission electron microscopy and UV-Vis absorption spectroscopy. The minimum inhibition concentration (MIC) was evaluated by the spectrophotometric microdilution method and turbidity. The minimum bactericide concentration (MBC) was evaluated in brain heart infusion plates, and cytotoxicity was evaluated by haemolytic activity. The MIC and MBC for NSF were, respectively, 33.54 ± 14.52 and 50.32 µg/mL; for SDF were 33.33 ± 14.43 and 50.0 µg/mL, respectively; and for CHX were 3.3 ± 0.5 and 6 µg/mL, respectively. An ANOVA for MIC gave P = 0.032, and for MBC P = 0.035. The cytotoxic effect of NSF compared to SDF demonstrated a statistically significant difference in the MIC value (t test P < 0.05). The NSF formulation may be effective against S. mutans with much lower doses, may have lower toxicity than SDF, and may not stain teeth.

Does acid etching enhance remineralisation of arrested white spot lesions?

AIM

To investigate the effect of acid etching procedure on the remineralisation of white spot lesions (WSL) which had undergone an initial phase of arrest, and to compare between the effect of fluoride and/or CPP-ACP on remineralisation before and after acid etching.

STUDY DESIGN

In vitro study.

METHODS

WSL were prepared in vitro on 130 human enamel slabs which were allocated into four experimental groups (N = 30) and one control group (N = 10). Changes in mineral content were registered weekly by Quantitative Light Induced Fluorescence QLF. When changes had arrested (after 8 weeks), the enamel surface of 20 slabs in each group were acid etched. The remineralisation process was continued until it slowed down again (after 5 weeks).

RESULTS

Mean fluorescence gain was 13.7 ± 0.9% in the fluoride group, 16.5 ± 1.1% in the CPP-ACP group, and 11.4 ± 1.2% in the combination of fluoride and CPP-ACP group.

CONCLUSIONS

There was a tendency toward better remineralisation after acid etching but this did not reach a significant level; the effect of etching was more pronounced in the presence of fluoride. Although CPP-ACP seemed to give a steadier rate of remineralisation over time when compared with fluoride, the overall remineralisation in the regimens was similar. In this model, combined treatment of fluoride and CPP-ACP did not have an extra benefit over the fluoride or CPP-ACP alone.

Nanoscale characterization of effect of L-arginine on Streptococcus mutans biofilm adhesion by atomic force microscopy

A major aetiological factor of dental caries is the pathology of the dental plaque biofilms. The amino acid L-arginine (Arg) is found naturally in saliva as a free molecule or as a part of salivary peptides and proteins. Plaque bacteria metabolize Arg to produce alkali and neutralize glycolytic acids, promoting a less cariogenous oral microbiome. Here, we explored an alternative and complementary mechanism of action of Arg using atomic force microscopy. The nanomechanical properties of Streptococcus mutans biofilm extracellular matrix were characterized under physiological buffer conditions. We report the effect of Arg on the adhesive behaviour and structural properties of extracellular polysaccharides in S. mutans biofilms. High-resolution imaging of biofilm surfaces can reveal additional structural information on bacterial cells embedded within the surrounding extracellular matrix. A dense extracellular matrix was observed in biofilms without Arg compared to those grown in the presence of Arg. S. mutans biofilms grown in the presence of Arg could influence the production and/or composition of extracellular membrane glucans and thereby affect their adhesion properties. Our results suggest that the presence of Arg in the oral cavity could influence the adhesion properties of S. mutans to the tooth surface.

The virulence of Streptococcus mutans and the ability to form biofilms

In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the oral cavity, known as dental caries, is a top leader. Streptococcus mutans, one of the many etiological factors of dental caries, is a microorganism which is able to acquire new properties allowing for the expression of pathogenicity determinants determining its virulence in specific environmental conditions. Through the mechanism of adhesion to a solid surface, S. mutans is capable of colonizing the oral cavity and also of forming bacterial biofilm. Additional properties enabling S. mutans to colonize the oral cavity include the ability to survive in an acidic environment and specific interaction with other microorganisms colonizing this ecosystem. This review is an attempt to establish which characteristics associated with biofilm formation--virulence determinants of S. mutans--are responsible for the development of dental caries. In order to extend the knowledge of the nature of Streptococcus infections, an attempt to face the following problems will be made: Biofilm formation as a complex process of protein-bacterium interaction. To what extent do microorganisms of the cariogenic flora exemplified by S. mutans differ in virulence determinants "expression" from microorganisms of physiological flora? How does the environment of the oral cavity and its microorganisms affect the biofilm formation of dominant species? How do selected inhibitors affect the biofilm formation of cariogenic microorganisms?

Nanoscale adhesion forces between enamel pellicle proteins and hydroxyapatite

The acquired enamel pellicle (AEP) is important for minimizing the abrasion caused by parafunctional conditions as they occur, for instance, during bruxism. It is a remarkable feature of the AEP that a protein/peptide film can provide enough protection in normofunction to prevent teeth from abrasion and wear. Despite its obvious critical role in the protection of tooth surfaces, the essential adhesion features of AEP proteins on the enamel surface are poorly characterized. The objective of this study was to measure the adhesion force between histatin 5, a primary AEP component, and hydroxyapatite (HA) surfaces. Both biotinylated histatin 5 and biotinylated human serum albumin were allowed to adsorb to streptavidin-coated silica microspheres attached to atomic force microscope (AFM) cantilevers. A multimode AFM with a Nanoscope IIIa controller was used to measure the adhesion force between protein-functionalized silica microspheres attached to cantilever tips and the HA surface. The imaging was performed in tapping mode with a Si3N4 AFM cantilever, while the adhesion forces were measured in AFM contact mode. A collection of force-distance curves (~3,000/replicate) was obtained to generate histograms from which the adhesion forces between histatin 5 or albumin and the HA surface were measured. We found that histatin 5 exhibited stronger adhesion forces (90% >1.830 nN) to the HA surface than did albumin (90% > 0.282 nN). This study presents an objective approach to adhesion force measurements between histatin 5 and HA, and provides the experimental basis for measuring the same parameters for other AEP constituents. Such knowledge will help in the design of synthetic proteins and peptides with preventive and therapeutic benefits for tooth enamel.

Effect of incorporation of remineralizing agents into bleaching gels on the microhardness of bovine enamel in situ

AIM

This study evaluated the effect of adding calcium or fluoride to 35% hydrogen peroxide (HP) bleaching gel and the effect of human saliva on the microhardness of sound and demineralized enamel, using an in situ model.

MATERIALS AND METHODS

Cylindrical bovine enamel specimens (3 × 2 mm) were divided into two groups (n = 30): sound enamel (SE) and demineralized enamel (DE). Each group was divided into three subgroups, according to the bleaching gel: 35% HP; 35% HP + calcium; 35% HP + fluoride. After bleaching therapy, the specimens were fixed to intraoral devices worn by 10 volunteers for 7 days. Surface enamel microhardness (SMH) was measured before and after bleaching procedures, and after 1 and 7 days of saliva exposure. Data were analyzed by Repeated Measures ANOVA (5%).

RESULTS

The variable time resulted in significant differences for SE and DE groups (p = 0.001). For SE, significantly lower SMH was detected for control at post-bleaching period in comparison to the baseline and after 7 days. For DE, the lowest mean values were obtained before bleaching, and the addition of calcium to the peroxide significantly increased enamel SMH. The exposure to human saliva resulted in increased SMH.

CONCLUSION

The addition of potential remineralizing agents into bleaching gels might play an important role in maintaining the microhardness of sound enamel and in inducing remineralization of artificially demineralized enamel right after bleaching, and the remineralizing action of human saliva might minimize the deleterious effects of bleaching gels on enamel. Clinical significance: The incorporation of calcium into HP bleaching gel might be beneficial for the initial phases of the bleaching procedure.

Proteomics of Human Teeth and Saliva

Teeth have been a focus of interest for many centuries – due to medical problems with them. They are the hardest part of the human body and are composed of three mineralized parts – enamel, dentin and cementum, together with the soft pulp. However, saliva also has a significant impact on tooth quality. Proteomic research of human teeth is now accelerating, and it includes all parts of the tooth. Some methodological problems still need to be overcome in this research field – mainly connected with calcified tissues. This review will provide an overview of the current state of research with focus on the individual parts of the tooth and pellicle layer as well as saliva. These proteomic results can help not only stomatology in terms of early diagnosis, identifying risk factors, and systematic control.

Sucrose substitutes affect the cariogenic potential of Streptococcus mutans biofilms

Streptococcus mutans is considered the primary etiologic agent of dental caries and contributes significantly to the virulence of dental plaque, especially in the presence of sucrose. To avoid the role of sucrose on the virulence factors of S. mutans, sugar substitutes are commonly consumed because they lead to lower or no production of acids and interfere with biofilm formation. This study aimed to investigate the contribution of sugar substitutes in the cariogenic potential of S. mutans biofilms. Thus, in the presence of sucrose, glucose, sucralose and sorbitol, the biofilm mass was quantified up to 96 h, the pH of the spent culture media was measured, the expression of biofilm-related genes was determined, and demineralization challenge experiments were conduct in enamel fragments. The presence of sugars or sugar substitutes profoundly affected the expression of spaP, gtfB, gtfC, gbpB, ftf, vicR and vicX in either biofilm or planktonic cells. The substitution of sucrose induced a down-regulation of most genes involved in sucrose-dependent colonization in biofilm cells. When the ratio between the expression of biofilm and planktonic cells was considered, most of those genes were down-regulated in biofilm cells in the presence of sugars and up-regulated in the presence of sugar substitutes. However, sucralose but not sorbitol fulfilled the purpose of reducing the cariogenic potential of the diet since it induced the biofilm formation with the lowest biomass, did not change the pH of the medium and led to the lowest lesion depth in the cariogenic challenge.