A Polygenic Score Predicts Caries Experience in Elderly Swedish Adults

Caries is a partially heritable disease, raising the possibility that a polygenic score (PS, a summary of an individual's genetic propensity for disease) might be a useful tool for risk assessment. To date, PS for some diseases have shown clinical utility, although no PS for caries has been evaluated. The objective of the study was to test whether a PS for caries is associated with disease experience or increment in a cohort of Swedish adults. A genome-wide PS for caries was trained using the results of a published genome-wide association meta-analysis and constructed in an independent cohort of 15,460 Swedish adults. Electronic dental records from the Swedish Quality Registry for Caries and Periodontitis (SKaPa) were used to compute the decayed, missing, and filled tooth surfaces (DMFS) index and the number of remaining teeth. The performance of the PS was evaluated by testing the association between the PS and DMFS at a single dental examination, as well as between the PS and the rate of change in DMFS. Participants in the highest and lowest deciles of PS had a mean DMFS of 63.5 and 46.3, respectively. A regression analysis confirmed this association where a 1 standard deviation increase in PS was associated with approximately 4-unit higher DMFS (P < 2 × 10-16). Participants with the highest decile of PS also had greater change in DMFS during follow-up. Results were robust to sensitivity analysis, which adjusted for age, age squared, sex, and the first 20 genetic principal components. Mediation analysis suggested that tooth loss was a strong mediating factor in the association between PS and DMFS but also supported a direct genetic effect on caries. In this cohort, there are clinically meaningful differences in DMFS between participants with high and low PS for caries. The results highlight the potential role of genomic data in improving caries risk assessment.

Polarization-Sensitive Optical Coherence Tomography for Monitoring De- and Remineralization of Bovine Enamel In Vitro

Early caries diagnosis still challenges dentistry. Polarization-sensitive optical coherence tomography (PS-OCT) is promising to detect initial lesions non-invasively in depth-resolved cross-sectional visualization. PS-OCT with determined degree of polarization (DOP) imaging provides an intuitive demineralization contrast. The aim of this study is to evaluate the suitability of DOP-based PS-OCT imaging to monitor controlled de- and remineralization progression for the first time and to introduce it as a valid, non-destructive in vitro detection method. Twelve standardized bovine enamel specimens were divided in different groups and demineralized with hydrochloric acid (HCl) as well as partly remineralized with fluoride over a 14-day pH-cycling experiment. The specimens were stored in artificial saliva and sodium chloride (NaCl), respectively. Progress measurements with PS-OCT were made with polarization-sensitive en faceand B-scan mode for qualitative evaluation. The specimens demineralized in HCl showed the most pronounced surface change (lowest DOP) and the most significant increase in depolarization. Additional fluoride treatment and the storage in artificial saliva resulted in the opposite (highest DOP). Therefore, DOP-based PS-OCT imaging appears to be a valuable technique for visualization and monitoring of enamel demineralization and remineralization processes in vitro. However, these findings need to be confirmed in human teeth ex vivo or in situ.

Non-Cariogenic Effect of Milk and Dairy Products on Oral Health in Children and Adolescents: A Scoping Review

Diet plays an important role in the etiopathology of dental caries. Milk and dairy products (DPs), especially in children and adolescents, are important sources of protein, calcium and phosphorus and could have an effect on dental and oral health. The aim of this scoping review was to analyze the scientific literature on the non-cariogenic effect of milk and DPs, with a focus on their potential to prevent dental caries in children and adolescents. PubMed, EMBASE, and Web of Science were searched for publications relevant to our topic from January 2013 to 30 September 2023. Thirty-eight studies were included in the qualitative analysis. The included studies highlight the properties of milk and DPs that contribute to enamel remineralization, exhibit antibacterial action, inhibit the growth of cariogenic bacteria, and promote a balanced oral microbiome. With regard to the addition of probiotics (PBs) and fluoride (F) to DPs, the mixed results of the studies analyzed did not allow a clear statement to be made about their non-cariogenic effects. However, several studies show that the addition of PBs can reduce cariogenic bacteria, create a protective barrier against pathogens and support the host's natural defense mechanisms. Further long-term and high-quality studies are needed to understand the impact of milk and its constituents on oral health in order to promote effective caries prevention strategies in children and adolescents.

Assessment of the developmental defects of the enamel in children and adolescents with sickle cell disease: A comparative study

BACKGROUND

Sickle cell disease (SCD) is the most important hemoglobinopathy in terms of frequency and social impact and can affect the stomatognathic system.

AIM

To assess and compare the developmental defects of the enamel (DDE) in children and adolescents with and without SCD.

DESIGN

This was a cross-sectional, analytical, and comparative study of 210 children and adolescents aged 5-18 years, who visited the Hematology and Hemotherapy Hospital of Pernambuco.

RESULTS

Developmental defects of the enamel were observed in 55.2% of the SCD patients and 35.2% of the non-SCD patients (healthy group; p < .05). In the SCD group, DDE were more common in females than in males (69.1% vs. 40.0%; p < .05). The incidence of DDE in the permanent teeth was higher in the upper arch than in the lower arch (SCD group, 13.1% vs. 4.6%; healthy group, 8.9% vs. 3.6%; p < .05).

CONCLUSION

Compared with the healthy group, the SCD patients were almost twice as likely to develop DDE, mostly affecting females and the permanent teeth. These findings suggest that individuals with SCD need early dental care to avoid future oral problems.

Effect of Mangifera Indica (Mango) on Dental Caries: A Systematic Review

The present study aimed to evaluate the effect of Mangifera indica (mango) on dental caries. The entire plant, including the leaves, fruit, roots, and flowers, has various therapeutic characteristics used for centuries to cure various illnesses. This systematic review aimed to identify an inexpensive, simple, and effective method of preventing and controlling dental caries. The search was performed among the studies written in English, the database of abstracts concentrating on the effects of Mangifera indica (Mango) on dental caries detected in Pubmed, Scopus, Google Scholar, and Central. In total, we find 37 articles. The relevant English language articles published up to August 2022 were collected, screened, and reviewed. Search words contained "Mangifera indica" and "dental caries" or "Streptococcus mutans" or "tooth demineralization." For our systematic review analysis, we included 3 randomized controlled trial studies studying a total of 130 people, of whom 110 were children aged 8 to 14 and 20 were adults aged 20 to 25. These experiments all employed mouthwash containing an extract from Mangifera indica. In conclusion, it has been proven in 2 separate studies that saliva's PH will increase significantly. In addition, a reduction of S. mutants has been observed in another research. Overall, it was concluded that mango extract mouthwash is highly effective in decreasing the bacteria that can cause dental caries. however, we firmly believe that conduction of more detailed in vivo studies regarding Mangifera indica implications in dental caries treatment is essentially needed for further confirmation.

Effect of bioactive glass-containing dentin adhesives on microshear bond strength of composite restorations

Background

In general, bioactive glasses (BAGs) can react with tissue minerals and promote remineralization. However, the application of BAG in bonding agents and its impact on bond strength remain uncertain due to insufficient information and limited research in this area.

Materials and Methods

This study employed a randomized controlled design to assess the effects of composite-bonding agents with varying BAG contents on shear bond strength and fracture pattern in sound and demineralized teeth, with and without thermocycling. Thus, 80 healthy third molars were randomly divided into two groups: sound teeth and demineralized teeth. Five bonding agents were applied to the prepared dentin surfaces, including four experimental composite-bonding agents with varying BAG content (0, 0.2, 0.5, and 2 wt%) and the Adper Single Bond commercial bonding as control. The shear bond strength of all samples was measured using a universal tester. The type of failure of each specimen was determined using a stereomicroscope. Kruskal-Wallis nonparametric test was performed on the obtained shear bond strength data followed by Mann-Whitney post hoc test with Bonferroni correction to determine statistical significance. The level of significance was considered P ≤ 0.05 for all tests and was adjusted by Bonferroni correction.

Results

Demineralization significantly decreased shear bond strength in the teeth samples. Adper Single Bond exhibited the highest shear bond strength values. The addition of BAG did not have a significant influence on shear bond strength, regardless of demineralization or thermocycling condition. Adhesive failure was the predominant type of failure in all groups.

Conclusion

The incorporation of BAG filler up to 2 wt% did not result in significant changes in shear bond strength. Experimental adhesive bonding agents with 2 wt% BAG content demonstrated shear bond strengths comparable to the commercial bonding agent in sound nontreated, sound thermocycled, demineralized nontreated, and demineralized thermocycled groups.

Influence of Different Bracket Adhesive Systems on Enamel Demineralization-An In Vitro Study

BACKGROUND

enamel demineralization is a common side effect of orthodontic therapy with fixed braces. The aim of the present in vitro study was to compare a conventional adhesive system and a modern adhesive system (APC Flash-Free [FF] technology) with regard to the demineralization of enamel by Streptococcus sobrinus (S. sobrinus).

METHODS

this in vitro study included premolar teeth and compared APC FF adhesive brackets (Group A, n = 15) with conventional adhesive brackets (Group B, n = 15) from the same company. Specimens were incubated with a positive control group (PCG, n = 5) and a negative control group (NCG, n = 5) in an S. sobrinus suspension for three weeks. To evaluate the grade of enamel demineralization, the samples were analyzed using a polarizing microscope.

RESULTS

the test specimens of group B with conventionally bonded bracket adhesive showed significantly greater (+10.8 μm) demineralization with regard to the penetration depth of the demineralization than the PCG (p = 0.012). Thus, there was a difference from group A with the new bracket adhesive of the FF brackets (+7.29 μm). Significantly, demineralization was more pronounced cervically than coronally in both groups, and it occurred cervically more frequently than grade 3 demineralization (p = 0.001).

CONCLUSIONS

it seems plausible that new orthodontic bracket adhesives and the modern FF adhesive system positively contribute to the reduction in enamel demineralization during orthodontic treatment.

Impact of Fluoride on Associations between Free Sugars Intake and Dental Caries in US Children

OBJECTIVE

Dental caries is the most prevalent chronic disease in US children, with the highest burden among Black and Hispanic youth. Sugars are a primary risk factor, but few studies have specifically measured intakes of free sugars and related this to dental caries or explored the extent to which water fluoride mitigates the cariogenicity of free sugars. Furthermore, the cariogenicity of certain free sugars sources, such as extruded fruit and vegetable products, is unclear.

METHODS

Using cross-sectional data on 4,906 children aged 2 to 19 y in the US National Health and Nutrition Examination Survey 2013-2016, we examined associations of free sugars intake with counts of decayed or filled primary tooth surfaces (dfs) and decayed, missing, or filled permanent surfaces (DMFS) in negative binomial regressions. Stratified models examined these associations in children with home water fluoride above or below the Centers for Disease Control and Prevention (CDC)-recommended level of 0.7 ppm.

RESULTS

Free sugars accounted for 16.4% of energy, primarily contributed by added sugars. In adjusted models, a doubling in the percentage of energy from free sugars was associated with 22% (95% confidence interval [CI], 1%-47%) greater dfs among children aged 2 to 8. A doubling in energy from added sugars was associated with 20% (95% CI, 1%-42%) greater dfs and 10% (95% CI, 2%-20%) greater DMFS in children aged 6 to 19 y. Beverages were the most important source of added sugars associated with increased caries. Other free sugars were not associated with dfs or DMFS. Associations between free sugars and caries were diminished among children with home water fluoride of 0.7 ppm or greater.

CONCLUSIONS

Free sugars intake, especially in the form of added sugars and specifically in sweetened beverages, was associated with higher dental caries. Water fluoride exposures modify these associations, reducing caries risk in the primary dentition of children whose home water meets recommended fluoride levels.

KNOWLEDGE TRANSFER STATEMENT

Intake of free sugars, especially in the form of added sugars and specifically in beverages, was associated with higher dental caries in US children in this study. Water fluoride exposure at CDC-recommended levels protected against caries, especially in the primary dentition. These findings suggest that household water fluoridation at CDC-recommended levels protects against the cariogenic potential of free and added sugars during childhood.

Bioactive Restorative Materials Applied over Coronal Dentine-A Bibliometric and Critical Review

The objective of the research was to examine the scientific literature concerning restorative materials with bioactive properties for the purpose of covering dentin. Searches were performed in various databases including MEDLINE, Scopus, Web of Science, Cochrane Library, Lilacs/BBO, and Embase. Inclusion criteria involved studies that utilized the terms "dentin" and "bioactive", along with "ion-releasing", "smart materials", "biomimetic materials" and "smart replacement for dentin". The information extracted included the title, authors, publication year, journal and the country of affiliation of the corresponding author. The studies were categorized based on their study design, type of material, substrate, analytical method, and bioactivity. A total of 7161 records were recovered and 159 were included for data extraction. Most of the publications were in vitro studies (n = 149), testing different types of materials in sound dentine (n = 115). Most studies were published in Dental Materials (n = 29), and an increase in publications could be observed after the year 2000. Most of the articles were from the USA (n = 34), followed by Brazil (n = 28). Interfacial analysis was the most investigated (n = 105), followed by bond strength (n = 86). Bioactivity potential was demonstrated for most tested materials (n = 148). This review presents insights into the current trends of bioactive materials development, clearly showing a severe lack of clinical studies.

Analysis of Dental Enamel Remineralization: A Systematic Review of Technique Comparisons

The demineralization process conditions the structure of the enamel and begins with a superficial decalcification procedure that makes the enamel surface porous and gives it a chalky appearance. White spot lesions (WSLs) are the first clinical sign that can be appreciated before caries evolves into cavitated lesions. The years of research have led to the testing of several remineralization techniques. This study's objective is to investigate and assess the various methods for remineralizing enamel. The dental enamel remineralization techniques have been evaluated. A literature search on PubMed, Scopus, and Web of Science was performed. After screening, identification, and eligibility processes 17 papers were selected for the qualitative analysis. This systematic review identified several materials that, whether used singly or in combination, can be effective in the process of remineralizing enamel. All methods have a potential for remineralization when they come into contact with tooth enamel surfaces that have early-stage caries (white spot lesions). From the studies conducted in the test, all of the substances used to which fluoride has been added contribute to remineralization. It is believed that by developing and researching new remineralization techniques, this process might develop even more successfully.

Evaluation of the effects of different mouthrinses on dental remineralization

BACKGROUND

Dental caries occurs with the release of organic acids from the fermentable carbohydrates metabolized by cariogenic microorganisms. Microbial, genetic, immunological, behavioral, and environmental factors play a role in the development and severity of dental caries.

OBJECTIVES

The aim of the present study was to investigate the possible effects of different mouthwash solutions on dental remineralization.

MATERIAL AND METHODS

This in vitro study compared the remineralization capacity of different mouthwash solutions applied topically to the enamel surface. A total of 50 tooth specimens were prepared from the buccal and lingual halves, with 10 teeth in each group: G1 (control); G2 (Listerine®); G3 (Sensodyne®); G4 (Oral B® Pro-Expert); and G5 (DentaSave® Zinc). Remineralization capacity was evaluated in all groups. The one-way analysis of variance (ANOVA) and the paired samples t test were used for statistical analysis, with a p-value <0.05 considered significant.

RESULTS

There were significant differences in the calcium (Ca)/phosphorus (P) atomic percentage (at%) ratio between the demineralized and remineralized dentin (p = 0.001), and between the demineralized and remineralized enamel (p = 0.006). Similarly, there were significant differences in the at% of P (p = 0.017) and zinc (Zn) (p = 0.010) between the demineralized and remineralized dentin. There was a significant difference in the at% of P (p = 0.030) between the demineralized and remineralized enamel. The Zn at% in enamel was significantly higher after remineralization in G5 as compared to the control group (p < 0.05). The images of the demineralized enamel showed the usual keyhole prism appearance, with intact prism sheaths and negligible inter-prism porosity.

CONCLUSIONS

The scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) findings seem to confirm the effectiveness of DentaSave Zinc for the remineralization of enamel lesions.

Regenerative biomineralization potential of commercially available remineralizing agents as a preventive treatment approach for tooth erosion - An in vitro laser-induced breakdown spectroscopy analysis

Context

In today's era, erosion is the most prevalent type of tooth wear. The prevention of demineralization with biomineralization is the most desired treatment.

Aim

The aim of this study is to evaluate and compare the surface remineralization potential of two remineralizing agents - self-assembling peptide P11-4 (SAP P11-4) and calcium silicate plus sodium phosphate (CSSP) salts on intact and demineralized enamel using laser-induced breakdown spectroscopy (LIBS).

Subjects and Methods

Sixteen maxillary premolars were decoronated and split into buccal and palatal halves embedded in acrylic resin with a total sample size of 32 designated into Group 1 (intact teeth) and Group 2 (demineralized teeth). Further subdivision into Groups 1a and 2a (SAP P11-4 group [n = 8]); Groups 1b and 2b (CSSP group [n = 8]), Group 2 was first exposed to Coca-Cola. Then, all groups were subjected to experimental LIBS. Groups 1a and 2a were treated with SAP P11-4 based product, i.e., CURODONT™ PROTECT gel. Groups 1b and 2b were treated with CSSP-based products regimen, i.e., REGENERATE Enamel Science™ Advanced Toothpaste and Advanced Enamel Serum. The LIBS assessment was redone for all groups to attain a change in Ca and P values.

Statistical Analysis Used

Inferential statistics were done using Wilcoxon signed-rank test (Before-After product application) and Mann-Whitney U-test (between the groups).

Results

According to the statistical evaluation there was a statistically significant difference (P < 0.05), in Ca and P values in demineralized teeth when both SAP P11-4 and CSSP groups were evaluated. Although Ca values exhibited a significant difference in intact teeth, P did not exhibit a significant difference on the application of both remineralizing agents. The remineralizing potential between the two agents, SAP P11-4 and CSSP groups. There was no statistically significant difference ( P <0.05) observed between the two agent's remineralization potential for intact and demineralized teeth.

Conclusion

SAP P11-4 and CSSP have the potential to remineralize both intact and demineralized enamel. There was increased remineralization in demineralized samples subjected to erosion.

Effect of Bioactive Filler Addition on the Mechanical and Biological Properties of Resin-Modified Glass Ionomer

The maintenance of affected dentin can promote the greater conservation of tooth structure. The development of materials that have properties capable of reducing the demineralizing potential and/or even helping in dental remineralization is important for conservative dentistry. This study aimed to evaluate, in vitro, the alkalizing potential, fluoride as well as calcium ion release ability, antimicrobial activity, and dentin remineralization properties of resin-modified glass ionomer cement (RMGIC) incorporated with a bioactive filler (niobium phosphate (NbG) and bioglass (45S5)). The study samples were grouped into RMGIC, NbG, and 45S5. The materials' alkalizing potential, ability to release calcium as well as fluoride ions, and antimicrobial properties concerning Streptococcus mutans UA159 biofilms were analyzed. The remineralization potential was evaluated using the Knoop microhardness test, which was performed at different depths. The alkalizing and fluoride release potential was higher for the 45S5 group (p < 0.001) over time. An increase in the microhardness of demineralized dentin was observed in the 45S5 and NbG groups (p < 0.001). No differences in biofilm formation were observed between the bioactive materials, although 45S5 exhibited lower biofilm acidogenicity at different time points (p < 0.001) and greater calcium ion release in the microbial environment. A resin-modified glass ionomer cement enriched with bioactive glasses, particularly 45S5, is a promising alternative for the treatment of demineralized dentin.

Association between respiratory diseases and molar-incisor hypomineralization: A systematic review and meta-analysis

The molar-incisor permineralização (MIH) is a qualitative enamel developing abnormality involving the occlusal and/or incisal third of one or more molars or permanent incisors, caused by systemic factors. Several systemic disorders and environmental factors, such as respiratory diseases, have been reported as probable causes of MIH. Thus, this work aimed to evaluate whether respiratory diseases and MIH are associated. The searches were carried out in electronic databases, including PubMed, Scopus, Web of Science, the Cochrane Library, LILACS, OpenGrey, and Google Scholar. The acronym PECO was used, in which the P (population) was humans in permanent dentition stage; (E-exposure) molar-incisor hypomineralization; (C-comparison) reference population and (O - outcome) respiratory diseases. After the search retrieval, the duplicates were removed, and the articles were evaluated by title and abstract; then, the papers were read and thoroughly assessed. After selection, the risk of bias assessment was performed using the Newcastle-Ottawa Scale (NOS) for observational studies. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool was used to assess the level of evidence. Three thousand six hundred and sixty six were found through the searches. After exclusion by duplicates, title, abstract, and full-reading, 13 articles remained. The articles included in this review evaluated the association of MIH with asthma, tonsilitis, pneumonia, and bronchitis. Most reports showed a low risk of bias. When exploring through GRADE, a very low level of evidence was found. We observed that the included studies showed that children with MIH had more respiratory diseases than the group that did not have MIH.

Systematic review registration

https://osf.io/un76d.

Are Molar-Incisor Hypomineralization and Hypomineralized Second Primary Molars Predictive of Dental Caries?: A Systematic Review

To estimate the prevalence of dental caries among children affected concomitantly with molar-incisor hypomineralization (MIH) and hypomineralized second primary molars (HSPM).Electronic databases, including Medline via PubMed, Cochrane Library, Scopus, and Science Direct, were searched. Studies written in English involving children with MIH-HSPM and dental caries were considered eligible. Two reviewers extracted the data according to the PRISMA statement and assessed the bias risk with the Newcastle-Ottawa Scale (NOS) criteria.Out of 535 studies identified in the initial research, only two articles were included in the present review. A significant association between MIH-HSPM and dental caries in permanent dentition was reported in the two included records (AOR: 3.70; p < 0.001). Children with MIH-HSPM expressed significantly higher DMFT and PUFA values than children without MIH-HSPM. However, dmft values did not differ significantly between children with and without HSPM (1.79 [2.4] vs. 1.78 [2.5]; 1.88 [2.73] vs. 1.59 [2.53], respectively.MIH-HSPM lesions were correlated with a higher prevalence and more severe carious lesions in permanent dentition. However, the results should be interpreted cautiously because the findings were generated by only two studies performed by the same authors. Thus, further well-designed studies are highly recommended.

The effect of multiple enamel conditioning on enamel micro-hardness

BACKGROUND

White spot formation is one of the common side effects in orthodontic treatments and multiple enamel conditioning might happen even during on session of fixed orthodontic treatments. The aim of the present study was to evaluate the impact of multiple enamel conditioning with different methods on enamel micro-hardness (MH).

MATERIALS AND METHODS

In this In vitro experimental study, the buccal surfaces of 105 extracted premolars were evaluated in seven groups: One control and six experimental groups. The enamel conditioning was performed in three ways: Etching with phosphoric acid 37%, etching with phosphoric acid 37% followed by primer application and conditioning with self-etch primer. The conditioning process in each way was also performed twice consecutively. The specimens were submitted in pH cycling model with demineralization and re-mineralization solutions for 14 days. Afterward Vickers MH test was applied with 0.981N force on the teeth for 10 s indentation time. Data were analyzed using One-Way ANOVA and Tukey HSD (honestly significant difference) test for multiple comparisons. A value of P < 0.05 was considered statistically significant.

RESULTS

MH analysis showed statistically significant differences between the control group and the other conditioned groups (P < 0.05). The groups conditioned with acid-etch and primer, particularly twice, showed the lowest amount of MH in comparison to other groups. Self-etch primer had the least effect on MH of the enamel. Single time etching without using primer, made no considerable difference when compared to multiple etching.

CONCLUSION

Etching process and covering the enamel with primer decrease enamel MH. Using self-etch primer is a more conservative method of enamel conditioning.

Prevention of demineralization during multi-bracketed fixed orthodontic treatment: An overview of systematic reviews

BACKGROUND

Demineralization during multi-bracketed fixed orthodontic treatment is a well-known problem.

AIM

To systematically evaluate the evidence for the prevention of enamel demineralization during multi-bracketed fixed orthodontic treatment.

DESIGN

Systematic reviews (with or without meta-analysis) that have appraised the primary studies on the prevention of demineralization during multi-bracketed fixed orthodontic treatment were searched systematically and included as per pre-defined eligibility criteria. The risk of bias of the included reviews was assessed by two authors using the ROBIS tool and AMSTAR-2 tool.

RESULTS

Twenty-nine reviews conducted on 128 exclusive primary studies were included for the present overview; 23 of these reviews were assessed to be of a high risk of overall bias, 5 were of low risk, and 1 review was of unclear risk of bias.

CONCLUSIONS

Predominantly, the published reviews have focused on fluorides, whereas some reviews have also studied the role of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), reminder therapy, lasers, and sealants. Professional fluorides, sealants, reminder therapy, and lasers might be valuable interventions to prevent demineralization during orthodontic treatment based on the conclusions of reviews with high quality; however, further studies are required to elucidate the role of CPP-ACP, chlorhexidine varnish, and powered toothbrushes.

Triacrylamide-Based Adhesives Stabilize Bonds in Physiologic Conditions

In this study, an acrylamide-based adhesive was combined with a thiourethane-based composite to improve bond stability and reduce polymerization stress, respectively, of simulated composite restorations. The stability testing was conducted under physiologic conditions, combining mechanical and bacterial challenges. Urethane dimethacrylate was combined with a newly synthesized triacrylamide (TMAAEA) or HEMA (2-hydroxyethyl-methacrylate; control) to produce a 2-step total-etch adhesive system. Methacrylate-based composites (70 wt% silanized filler) were formulated, containing thiourethane oligomers at 0 (control) or 20 wt%. Standardized preparations in human third molars were restored; then, epoxy replicas were obtained from the occlusal surfaces before and after 7-d storage in water or with Streptococcus mutans biofilm, which was tested after storage in an incubator (static) or the bioreactor (mechanical challenge). Images were obtained from the replicas (scanning electron microscopy) and cross sections of the samples (confocal laser scanning microscopy) and then analyzed to obtain measurements of gap, bacterial infiltration, and demineralization. Microtensile bond strength of specimens stored in water or biofilm was assessed in 1-mm2 stick specimens. Data were analyzed with analysis of variance and Tukey's test (α = 0.05). HEMA-based materials had greater initial gap measurements, indicating more efficient bonding for the acrylamide materials. When tested in water, the triacrylamide-based adhesive had smaller gaps in the incubator or bioreactor. In the presence of biofilm, there was less difference among materials, but the acrylamide/thiourethane combination led to statistically lower gap formation in the bioreactor. HEMA and TMAAEA-based adhesives produced statistically similar microtensile bond strengths after being stored in water for 7 d, but after the same period with biofilm-challenged specimens, the TMAAEA-based adhesives were the only ones to retain the initial bond strength values. The use of a stable multiacrylamide-based adhesive led to the preservation of the resin-dentin bonded interface after a physiologically relevant challenge. Future studies will include a multispecies biofilm model.

Dual Functions of MDP Monomer with De- and Remineralizing Ability

Methacryloyloxydecyl dihydrogen phosphate (MDP) has been speculated to induce mineralization, but there has been no convincing evidence of its ability to induce intrafibrillar mineralization. Polymers play a critical role in biomimetic mineralization as stabilizers/inducers of amorphous precursors. Hence, MDP-induced biomimetic mineralization without polymer additives has not been fully verified or elucidated. By combining 3-dimensional stochastic optical reconstruction microscopy, surface zeta potentials, contact angle measurements, inductively coupled plasma-optical emission spectroscopy, transmission electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy with circular dichroism, we show that amphiphilic MDP can not only demineralize dentin by releasing protons as an acidic functional monomer but also infiltrate collagen fibrils (including dentin collagen), unwind the triple helical structure by breaking hydrogen bonds, and finally immobilize within collagen. MDP-bound collagen functions as a huge collagenous phosphoprotein (HCPP), in contrast to chemical phosphorylation modifications. HCPP can induce biomimetic mineralization itself without polymer additives by alternatively attracting calcium and phosphate through electrostatic attraction. Therefore, we herein propose the dual functions of amphiphilic MDP monomer with de- and remineralizing ability. MDP in the free state can demineralize dentin substrates by releasing protons, whereas MDP in the collagen-bound state as HCPP can induce intrafibrillar mineralization. The dual functions of MDP monomer with de- and remineralization properties might create a new epoch in adhesive dentistry and preventive dentistry.

Diet drinks and dental caries among U.S. adults: cluster analysis

BACKGROUND

In recent years, the consumption of sugar sweetened beverages has been declining, while low calorie sweetener and diet beverage consumption is increasing. Evidence about the effect of diet drinks on dental caries is insufficient, and has not accounted for the complexity of beverage consumption patterns. Therefore, the aim of this study is to examine the association between consuming diet drinks and dental caries among US adults.

METHODS

We analyzed 2011-2014 NHANES dietary data of adults using cluster analysis, with individuals grouped based on their beverage consumption. Clusters were identified based on the R-square statistic and the local peak of the pseudo F statistic. Survey procedure and sample weights were used to account for the complex NHANES sampling design.

RESULTS

Four beverage consumption patterns were identified: "high soda", "high diet drinks", "high coffee/tea" and "high water". The "High soda" cluster was the only one associated with higher DMFT after controlling for confounders (β=1.02, 95% CI=0.42 - 1.63), whereas DT was associated with "high soda" (β=0.45, 95% CI=0.25 - 0.64) and "high coffee/tea" (β=0.24, 95% CI=0.01 - 0.47). On the other hand, the "high diet drinks" cluster was neither associated with DMFT (β=0.69, 95% CI=0.51 - -0.35) nor DT (β=0.07, 95% CI=-0.21 - 0.35).

CONCLUSION

Diet drinks consumption may not be associated with increased risk of dental caries. However, more studies should be conducted in order to confirm this finding.

Effects of Silver Diamine Nitrate and Silver Diamine Fluoride on Dentin Remineralization and Cytotoxicity to Dental Pulp Cells: An In Vitro Study

Silver diamine nitrate (SDN) is expected to help control caries similar to silver diamine fluoride (SDF). The aim of this study was to determine the mineral precipitation in demineralized dentin and the cytotoxicity of SDN and SDF to dental pulp cells. Demineralized dentin specimens were prepared, and SDF, SDN, or water (control) was applied. The specimens were then remineralized in simulated body fluid for 2 weeks. The mineral precipitation in the specimens was examined using FTIR-ATR, SEM-EDX, and synchrotron radiation X-ray tomographic microscopy (SRXTM). Additionally, the cytotoxicity of SDF and SDN to human dental pulp stem cells was analyzed using an MTT assay. The increase in FTIR spectra attributable to apatite formation in demineralized dentin in the SDF group was significantly higher compared to the SDN and control groups (p < 0.05). Dentinal tubule occlusion by the precipitation of silver salts was detected in both SDF and SDN groups. The mineral density as shown in SRXTM images and cytotoxicity of both SDN and SDF groups were comparable (p > 0.05). In conclusion, SDF demonstrated superior in vitro apatite formation compared to SDN. However, the degree of mineral precipitation and cytotoxic effects of both were similar.

Quantification of sugar intake and mineralization of teeth in 13-15-year-old subjects - A pilot study

BACKGROUND

Dental caries begins with the initiation of demineralization which is a reversible process. Diet, especially intake of sugar, is an important aetiological factor for demineralization of enamel which eventually leads to caries.

AIM

This study aims to understand the quantitative relationship between sugar consumption and mineralization by finding out the change in mineralization of teeth as a result of the change in the sugar score.

SETTINGS AND DESIGN

This interventional study was done among 119 teeth of 19 subjects who were between the ages of 13-15 years in Hubli city.

MATERIALS AND METHODS

Sugar score was calculated from a 5-day diet history of the subjects and a DIAGNOdent pen was used to indicate the mineralization value of the teeth before the intervention. Diet counseling was given as an intervention after which sugar score and DIAGNOdent scores were measured again after 14 days and compared with the baseline values.

STATISTICAL ANALYSIS

Descriptive statistics and a linear regression analysis was done to determine the relationship between the variables.

RESULTS

Sugar score and DIAGNOdent score after 14 days were found to have reduced significantly by 41.6% and 20.3% respectively from the baseline values. The Linear Regression indicated that a reduction of sugar score by 5 resulted in a decrease of DIAGNOdent score by 0.16.

CONCLUSION

The findings of the present study suggest that the modification of sugar consumption brought about a significant improvement in the mineralization of the demineralized teeth thus making diet counseling an effective preventive strategy for caries prevention.

The dual anti-caries effect of carboxymethyl chitosan nanogel loaded with chimeric lysin ClyR and amorphous calcium phosphate

In this study, we evaluated the anti-biofilm and anti-demineralization abilities of a novel material, CMC-ClyR-ACP nanogel, designed by loading the chimeric lysin ClyR and amorphous calcium phosphate (ACP) into a nanocarrier material carboxymethyl chitosan (CMC), in a demineralization model. Dynamic light scattering, transmission electron microscopy, and Fourier transmission infrared spectroscopy showed that CMC-ClyR-ACP nanogel was synthesized successfully. Enamel samples prepared from premolars were divided into five groups according to their treatments with: (i) double distilled water ddH₂ O, (ii) CMC-ACP, (iii) CMC-ClyR-ACP, (iv) ClyR, or (v) 0.12% chlorhexidine. Streptococcus mutans was allowed to form biofilms on the teeth for two days before treatment procedures were carried out from day 3 to day 6. The relative biofilm viability analyzed by Cell Counting Kit-8 showed that it was significantly lower (at 55.7%) for CMC-ClyR-ACP than seen for ddH₂ O (89.9%), which was consistent with result of confocal laser scanning microscopy. The percentage surface hardness loss of CMC-ClyR-ACP (29.2%) was significantly lower than that of CMC-ACP (51.0%) and ClyR (58.7%) alone, and there was no significant difference between CMC-ClyR-ACP and chlorhexidine (26.9%), which was confirmed by scanning electron microscopy. Therefore, CMC-ClyR-ACP nanogel may be an effective strategy for the control of enamel demineralization.

Effect of casein-phosphopeptide amorphous calcium phosphate and fluoride with/without erbium, chromium-doped yttrium, scandium, gallium, and garnet laser irradiation on enamel microhardness of permanent teeth

BACKGROUND

Laser therapy, along with the use of fluoridated compounds is a novel technique suggested for caries prevention. Casein phosphopeptide amorphous calcium phosphate (CPP-ACP) is another product suggested for this purpose. This study compared the effect of CPP-ACP and fluoride with/without Erbium, chromium-doped yttrium, scandium, gallium, and garnet laser irradiation on enamel microhardness of permanent teeth.

MATERIALS AND METHODS

This in vitro experimental study evaluated 35 extracted third molars. The teeth were decoronated, and the crowns were split into buccal and lingual halves. The samples were randomly divided into seven groups (n = 10) of GC Tooth Mousse, MI Paste Plus, laser, fluoride varnish, laser + GC Tooth Mousse, laser + MI Paste Plus, and laser + fluoride varnish. The baseline microhardness was measured before the intervention. After the intervention, the samples were kept in artificial saliva for 1 h and were then immersed in the demineralizing solution for 3 h followed by 21 h of immersion in the remineralizing solution for a total period of 12 days. Finally, the teeth were kept in the remineralizing solution for 2 more days. The secondary microhardness of the teeth was then measured. Data were analyzed using the Shapiro-Wilk test, two-way ANOVA, and Tukey's Honestly Significant Difference test.

RESULTS

The fluoride varnish (14.31%) and laser + fluoride varnish (18.79%) groups experienced minimum reduction in microhardness, while the GC Tooth Mousse group experienced maximum reduction in microhardness (91.64%) (P < 0.001). Laser irradiation before the application of remineralizing agents increased the microhardness only in laser + GC Tooth Mousse group (P < 0.001).

CONCLUSION

Fluoride varnish increased the enamel microhardness, while GC Tooth Mousse had no such effect. Laser therapy before the application of remineralizing agents did not significantly enhance enamel resistance to demineralization.

Fluoride release and remineralizing potential of varnishes in early caries lesions in primary teeth

This study evaluated the fluoride (F) release and remineralizing potential of varnishes containing sodium fluoride (5% NaF), 5% NaF with CPP-ACP and 5% NaF with TCP in early caries lesions in primary teeth. To determine the F release at 1, 4, 6, 24, 72, and 168 hr, strips were covered with the varnishes and immersed in purified water (n = 7). The varnishes and purified water (negative control) were applied on enamel blocks with early caries lesions (n = 16). Enamel blocks were stored in artificial saliva and submitted to a pH-cycling. The area of enamel hardness loss (ΔS) was analyzed by microhardness, lesion depth by polarized light microscopy (PLM) and the chemical analysis by Energy-dispersive X-ray spectroscopy. Data were submitted to Shapiro-Wilk, two-way and one-way ANOVA, Tukey and paired t-tests (α = 5%). All varnishes released F, but 5% NaF with CPP-ACP had the highest release at 4, 6, 24, and 72 hr (p < .05) followed by 5% NaF with TCP and 5% NaF. No significant difference in ΔS was observed among varnishes (5% NaF = 4,098.4 ± 1,407.9; 5% NaF with CPP-ACP = 4,164.0 ± 1,019.3; 5% NaF with TCP = 4,183.2 ± 1,527.2; p = .999), but all of them differed from the negative control group (6,757.8 ± 2,274.7; p < .001). Lesion depth was lower in varnishes groups compared to negative control (% reduction: 5% NaF = 41.8%, 5% NaF with CPP-ACP = 38.8%, and 5% NaF with TCP = 36.3%; p < .001). Similar Ca, P, and Ca/P ratio percentages among groups and F was not detected after the treatments. All fluoride varnishes showed potential to enhance remineralization of early caries lesions in primary teeth.

Association between demarcated enamel hypomineralization on second primary molars and dental caries in childhood

Hypomineralized Second Primary Molars (HSPM) is the name used to describe the presence of demarcated enamel hypomineralization in second primary molars. HSPM has been compared with Molar Incisor Hypomineralization (MIH) as regards its clinical appearance and consequences. The aim of this study was to investigate associations between HSPM and dental caries in childhood. It was a cross-sectional populationbased study that included 216 children aged 4-6 years from public schools in Botelhos, Brazil. Children with all second primary molars erupted were eligible for participation. Clinical examination was performed by one calibrated examiner. HSPM was recorded according to modified European Academy of Paediatric Dentistry criteria. The main outcome was dental caries experience as indicated by the dmft index (%dmft>0) according to WHO criteria. Chi-square test and Logistic Regression Model were used to adjust the results for effects of covariates Among the 216 children examined, 22.2% presented HSPM. After adjustment for logistic regression, children with HSPM were found to have a 2.28 times greater chance of presenting dental caries. Our results reinforce the importance of HSPM in caries development in children, which should be considered by public health dentists in the process of planning actions aimed at this population.

Establishment of microcosm biofilm models that reproduce a cariogenic diet intake

Biofilms were developed from human saliva on bovine enamel discs in four experimental conditions to investigate dental caries development: feast and famine (M1), abundance and scarcity (M2), three meals daily (M3), and three meals plus two snacks daily (M4). The main difference between these models was the diet for microbial growth. The evaluations included verifying the pH of the spent culture media and analyzing the enamel discs for demineralization (microhardness and roughness) and biofilms (biomass, viable populations of mutans streptococci, and total microbiota). Two major behaviors were observed: M1 and M2 promoted an acidic environment, while M3 and M4 maintained pH values closer to neutral. The demineralization process was slower in the neutral groups but more pronounced in M3, while a greater increase in microbiota and biomass was observed over time for both neutral groups. Thus, the M3 model was better at mimicking the oral environment that leads to demineralization.

Evaluation of new compositions of 10% hydrogen peroxide-based bleaching agents containing trimetaphosphate and fluoride on enamel demineralization

This study evaluated the effect on enamel demineralization of 10% hydrogen peroxide (H₂ O₂ ) gels containing different concentrations of sodium trimetaphosphate (TMP) and sodium fluoride (NaF) combined with the daily use of fluoridated or placebo dentifrice. Bovine enamel blocks were selected by surface hardness (n = 72) and randomly assigned to one of the following experimental treatments: 10% H₂ O₂ ; 10% H₂ O₂  + 3% TMP + 0.1% NaF; and 10% H₂ O₂  + 0.3% TMP + 0.05% NaF, each with or without fluoridated dentifrice. H₂ O₂ -based gels were applied for 30 min d^-1 followed by treatment with dentifrice (1 min). Enamels blocks were stored in artificial saliva at 37°C between sessions during the 14 days of experiment. Percentage of surface hardness loss (%SH) was calculated, and the blocks were cut into halves to analyze cross-sectional hardness (ΔKHN). Polarized light microscopy images were obtained of the longitudinal sections of the samples. Enamel treated with fluoridated dentifrice presented lower hardness loss than those treated with placebo dentifrice (%SH and ΔKHN). Use of TMP- and NaF-based gels, regardless of concentration, led to the lowest %SH values. Specimens treated with 10% H₂ O₂ gel had the highest %SH and ΔKHN values. Gels with 10% H₂ O₂  + 3% TMP + 0.1% NaF showed the lowest ΔKHN values. Microscopy images clearly showed that the addition of TMP and NaF to the H₂ O₂ -based gels was effective in reducing the loss of hardness, and the fluoridated dentifrice helped minimize it in all treatments.

Fluoride Mode of Action: Once There Was an Observant Dentist

The discovery and implementation of fluoride in the prevention of dental caries is often praised as one of the most important achievements in health care. In the early 20th century, it took 30 y to identify fluoride as the cause of enamel mottling but also of reduced caries prevalence in a population drinking water containing fluoride. Similarly, from 1960 to 1990, it took major efforts to unravel the working mode of fluoride in such detail that a rational scheme of caries prevention could be formulated. This article describes the scientific struggle leading to a consensus on the topic. For a historic purpose, the field, the actors, and their main research achievements are described. Ultimately it was generally agreed that the effect of fluoride is primarily topical by fluorides in the oral fluids rather than systemic by incorporation of fluoride in the enamel mineral crystals. Fluoride concentrations, even <1 mg/L, enhance the deposition of calcium phosphates during remineralization of enamel (and dentin). Similarly, such low levels of fluoride are effective in reducing the dissolution of the calcified tissues. This understanding has led to the development of fluoride-containing caries-preventive products that had an undisputed beneficial effect on the levels of dental caries.

Effectiveness of different adjunctive interventions in the management of orthodontically induced white spot lesions: A systematic review of systematic reviews and meta-analyses

The purposes of this review were to appraise the current evidence on the management of orthodontically induced white spot lesions (OIWSLs) and to choose the best evidence from among conflicting systematic reviews. The published literature was searched from inception through November 2019 in 5 databases. Only systematic reviews and/or meta-analyses were eligible for inclusion. Methodological quality was assessed using A Measurement Tool to Assess Systematic Reviews-2 (AMSTAR-2). The Jadad decision algorithm was applied to choose the best available evidence from among discordant reviews. Thirteen publications were included. The interventions reported in the management of OIWSLs were topical fluorides, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-containing products, fluoridecontaining bonding materials, laser therapy, resin infiltration, and micro-abrasion. The methodological quality of the reviews ranged between moderate and critically low according to the AMSTAR-2 tool. Based on the Jadad decision algorithm criteria, topical fluorides yielded a 25-30% prevention of OIWSLs; however, their effect on reversing OIWSLs was unclear. The CPP-ACP products were effective in both preventing and reversing OIWSLs. No differences were noted between fluoride-releasing adhesives and conventional adhesives. Laser irradiation was effective in preventing OIWSLs, with some concerns about the argon laser at a certain setting. Finally, there is a lack of reliable evidence supporting the efficacy of resin infiltration or micro-abrasion due to the limited number of available studies. Based on the currently available information, topical fluorides and laser irradiation are effective in preventing OIWSLs. The CPP-ACP products are effective in preventing and reversing OIWSLs. Fluoride-releasing adhesives have no effect on OIWSL prevention.

The Efficacy of Soprolife® in Detecting in Vitro Remineralization of Early Caries Lesions

Objectives

This randomized controlled in vitro 4-arm trial study aimed to evaluate the efficacy of SoproLife^® in detecting and quantifying in vitro remineralization with early caries lesions.

Material and Methods

Sixty human teeth were randomly assigned into four equal groups. Groups 1 and 2 were prophylactically cleaned; groups 3 and 4 were not. Group 1 received treatment with MI Varnish^® and Recaldent™ for 30 days. Group 2 was treated similarly, but without MI Varnish^®. Group 3 was treated as 1 and Group 4 as 2. Mineral composition was obtained using scanning electron microscopy with energy dispersive X-ray analysis SoproLife^® camera images on the occlusal surfaces were analysed for grey value distribution and difference in mean intensity values (DI). Paired t-test and Mann-Whitney-U test were used for intragroup comparison between baseline and T1. Kruskal-Wallis followed by Mann-Whitney-U tests were used for inter-group comparisons at T1.

Results

All groups exhibited a significant increase in calcium content and calcium-to-phosphorus ratio (P < 0.05), except Group 4 (Group 1 showed the greatest increase, then Groups 3 and 2). Grey intensity values decreased in all groups (P < 0.05). Group 1 showed the greatest change in DI (16.82 [SD 12.07]), followed by Group 3 (12.46 [SD 9.41]), 2 (10.45 [SD 7.76]), and 4 (6.46 [SD 6.21]). The difference in DI was different between the compared groups (P = 0.038); Groups 1 and 3 exhibited a greater DI compared with 4 (P < 0.01).

Conclusions

Within the limitations of this study, SoproLife^® is effective for early detection and for longitudinally monitoring the remineralization after Recaldent™ therapy.

In Vitro Influence of Prophylaxis Cleaning on Enamel Remineralization with Casein Phosphopeptide-Amorphous Calcium Phosphate

Objectives

This randomized controlled in vitro 4-arm trial study aimed to study the remineralization potential of Recaldent™ and assess the effects of prophylaxis cleaning and MI Varnish^® on enhancing this remineralization potential.

Material and Methods

Sixty human teeth were randomly assigned into equal samples (A/B). Sample A was prophylactically cleaned, randomly divided into equal samples (1/2). Sample A1 received treatment with MI Varnish^® and Recaldent™ for 30 days. Sample A2 was treated similarly but without MI Varnish^®. Sample B did not receive prophylaxis cleaning and was divided into equal samples (1/2). Sample B1 was treated as A1 and sample B2 as A2. The teeth were examined for mineral composition at baseline, after the interventions (T1), and after prophylaxis cleaning (T2). Study outcomes were mineral content (% weight of carbon [C], phosphorus [P], calcium [Ca], oxygen [O], chlorine [Cl], sodium [Na] and silicon [Si]) and calcium-phosphorus ratio (Ca/P).

Results

All groups had similar mineral composition at baseline. At T1, sample B2 exhibited least P, Ca and Ca/P content. Samples A1 and B1 showed higher content of P and Ca, compared to B2 (A1 only exhibited higher Ca/P). Sample A2 exhibited lowest Cl and Na content. At T2, sample A1 exhibited lowest C, P, O and Si content (highest Ca/P). Sample A2 showed least Ca/P, and highest Na content.

Conclusions

Teeth treated by Recaldent™ proceeded by prophylaxis cleaning or MI Varnish^® showed remineralization, especially when receiving both interventions. This superior effect persisted even after a second cleaning. Further trials are necessary to provide conclusive evidence in humans.

Impact of molar incisor hypomineralization on quality of life in children with early mixed dentition: A hierarchical approach

BACKGROUND

Molar incisor hypomineralization (MIH) is associated with unfavourable dental conditions such as dental caries and may consequently impact oral health-related quality of life (OHRQoL).

OBJECTIVE

To assess the impact of MIH on OHRQoL in children with early mixed dentition.

METHOD

A population-based cross-sectional study of 728 8-year-old children from the public school system in Curitiba, Brazil, was conducted. The Child Perception Questionnaire for 8- to 10-year-olds (CPQ_8-10 ) was used to evaluate OHRQoL. MIH was diagnosed according to the European Academy of Paediatric Dentistry (EAPD) criteria. The assessments of MIH, dental caries, and malocclusion were performed by four calibrated examiners (κ ≥ 0.80). Demographic and socioeconomic data (DSE) were obtained from the children's parents/caregivers using a structured questionnaire. The analysis of OHRQoL determinants was performed through a three-level hierarchical approach: mesial (DSE), intermediate (clinical conditions), and distal (child's oral self-perception), using Poisson regression with robust variance (α = 0.05).

RESULTS

The prevalence of MIH was 12.1% (95% CI: 10-15). An association was found between MIH and OHRQoL in the "oral symptoms" domain of the CPQ_8-10 (PR: 1.07, 95% CI: 1.03-1.11, P < 0.001) after adjusting for other clinical variables and DSE.

CONCLUSION

Molar incisor hypomineralization was associated with a greater impact on OHRQoL in children's oral symptoms.

Prevention of white spot lesions using three remineralizing agents: An in vitro comparative study

Background. Enamel demineralization around orthodontic brackets is an important clinical problem. This study sought to compare the efficacy of sodium fluoride (NaF), casein phosphopeptide amorphous calcium phosphate fluoride (CPP-ACP-F; MI Paste Plus) and a water-based cream (Remin Pro), which contains hydroxyapatite and fluoride for prevention of enamel demineralization.

Methods. Fifty-six sound human premolars extracted for orthodontic purposes were collected. After cleaning, the crowns were mounted in acrylic resin and all the surfaces were coated with nail varnish except for a 3×4-mm window on the buccal surface. The samples were randomly divided into four groups of 14 and subjected to pH cycling for 14 days, during which the teeth were immersed in artificial saliva for 21 hours and in demineralizing agent for three hours daily. Before transferring the samples from the saliva to the demineralizing solution, the remineralizing agent (0.05% NaF, MI Paste Plus or Remin Pro Paste, depending on the group) was applied on the samples once a day for five minutes. No remineralizing agent was used in the control group. Surface microhardness of samples was measured by Vickers microhardness tester at baseline and after the intervention. The data were analyzed using one-way ANOVA, ANCOVA, Bonferroni test and Tukey test. Statistical significance was set at P<0.05.

Results. The mean microhardness was significantly different between the test and control groups (P<0.0001). Other differences were not significantly different (P>0.05).

Conclusion. The results showed that 0.05% NaF was more efficient than Remin Pro and MI Paste Plus for prevention of white spot lesions (WSLs). Remin Pro and MI Paste Plus were not significantly difference from the control group in this regard.

CPP-ACP Promotes SnF2 Efficacy in a Polymicrobial Caries Model

Dental caries is associated with plaque dysbiosis, leading to an increase in the proportions of acidogenic and aciduric bacteria at the expense of alkali-generating commensal species. Stannous fluoride (SnF₂) slows the progression of caries by remineralization of early lesions but has also been suggested to inhibit glycolysis of aciduric bacteria. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) promotes fluoride remineralization by acting as a salivary biomimetic that releases bioavailable calcium and phosphate ions, and the peptide complex has also been suggested to modify plaque composition. We developed a polymicrobial biofilm model of caries using 6 bacterial species representative of supragingival plaque that were cultured on sound human enamel and pulsed with sucrose 4 times a day to produce a high cariogenic challenge. We used this model to explore the mechanisms of action of SnF₂ and CPP-ACP. Bacterial species in the biofilms were enumerated with 16S rRNA gene sequence analyses, and mineral loss and lesion formation were determined in the enamel directly under the polymicrobial biofilms via transverse microradiography. The model tested the twice-daily addition of SnF₂, CPP-ACP, or both. SnF₂ treatment reduced demineralization by 50% and had a slight effect on the composition of the polymicrobial biofilm. CPP-ACP treatment caused a similar inhibition of enamel demineralization (50%), a decrease in Actinomyces naeslundii and Lactobacillus casei abundance, and an increase in Streptococcus sanguinis and Fusobacterium nucleatum abundance in the polymicrobial biofilm. A combination of SnF₂ and CPP-ACP resulted in a greater suppression of the acidogenic and aciduric bacteria and a significant 72% inhibition of enamel demineralization.

Effect of resin infiltration and microabrasion on the microhardness, surface roughness and morphology of incipient carious lesions

OBJECTIVE

The effects of resin infiltration and microabrasion on incipient carious lesions by surface microhardness, roughness and morphological assessments, and resistance to further acid attack of treated lesions were evaluated.

MATERIAL AND METHODS

Eighty artificially-induced incipient lesions were randomly divided into five groups (n = 16): resin infiltration with an adhesive resin (Excite F, Ivoclar Vivadent, Schaan, Liechtenstein), resin infiltration with a resin infiltrant (Icon, DMG, Hamburg, Germany), microabrasion without polishing (Opalustre, Ultradent, South Jordan, UT, USA), microabrasion with polishing (Opalustre, Ultradent, Diamond Excel, FGM, Joinville, SC, Brazil), and distilled water (control group). All specimens were exposed to demineralization for another 10 d. Microhardness, roughness and morphological assessments were done at baseline, following initial demineralization, treatment and further demineralization. Data were analysed by the Kruskal-Wallis, Friedman's and Bonferroni tests (p < .05).

RESULTS

Enamel lesions treated with resin infiltrant and microabrasion demonstrated similar hardness values, with a nonsignificant difference compared with sound enamel. Resin infiltration demonstrated lower roughness values than those of microabrasion, and the values did not reach the values of sound enamel. Further demineralization for 10 d did not affect the hardness but increased the roughness of infiltrated and microabraded enamel surfaces. Polishing did not influence the roughness of microabraded enamel surfaces. After resin infiltration, porosities on enamel were sealed completely. The surface structure was similar to that of the enamel conditioning pattern for microabraded enamel lesions.

CONCLUSIONS

Within the limitations of this study, the icon infiltration and microabrasion technique appeared to be effective for improving microhardness. Icon appeared to provide reduced roughness, although not equal to sound enamel. Further research is needed to elucidate their clinical relevance.

Retention Improvement in Fluoride Application with Cold Atmospheric Plasma

This study aimed to apply fluoride formulations to enamel with cold atmospheric plasma (CAP) and analyze the fluoride uptake, retention, and acid resistance quantitatively. Human enamel specimens were divided randomly into 2 groups: group APF1, 1.23% acidulated phosphate fluoride (APF) gel; group APF2, 1.23% APF gel with CAP. Fluoride and CAP were applied to the samples 4 times at 1-wk intervals. The specimens were also stored in artificial saliva for 4 wk to evaluate the retention of fluoride. The fluoride content on the fluoride-treated enamel was measured by an electron probe microanalyzer. To detect the resistance to demineralization, the calcium-to-phosphate ratio of the enamel samples was measured after the application of APF gel with or without CAP, followed by soaking in the demineralization solution. In groups APF1 and APF2, the amount of fluoride detected increased depending on the application frequency, and more fluoride was detected in group APF2 than in group APF1. In the experiment examining the maintenance effect, fluoride was not detected in group APF1, whereas fluoride was detected in group APF2 up to the fourth week. As for the resistance to demineralization, the calcium-to-phosphate ratio of the enamel treated with APF and CAP was higher than that treated with APF alone, and it increased with the frequency of treatment. This study suggests that the combination treatment of CAP and fluoride improves retention of fluoride on the enamel and resistance to demineralization when compared with treatment with fluoride alone.

A New Laser-Processing Strategy for Improving Enamel Erosion Resistance

In the present study, a new automatic laser-processing strategy allowing standardized irradiation of natural tooth areas was investigated. The objective was to find a combination of laser parameters that could cause over a 600°C temperature increase at the enamel surface while not damaging enamel, avoiding temperature change above 5.5°C in the pulp and increasing enamel erosion resistance. Seventy-seven bovine enamel samples were randomly divided into 6 laser groups and 1 negative control (C/no treatment/ n = 11). A scanning strategy (7 × 3 mm) was used for the CO₂ laser treatment (λ = 10.6 µm, 0.1-18 J/cm²) with different pulse durations-namely, 20 µs (G20), 30 µs (G30), 55 µs (G55), and 490 µs (G490), as well as 2 modified pulse distances (G33d, G40d). Measurements of temperature change were performed at the surface (thermal camera/50 Hz), at the underside (thermocouples), and at the pulp chamber using a thermobath and human molars ( n = 10). In addition, histology and X-ray diffraction (XRD/ n = 10) were performed. Erosion was tested using an erosive cycling over 6 d, including immersion in citric acid (2 min/0.05 M/pH = 2.3) 6 times daily. Surface loss was measured using a profilometer and statistical analysis with a 2-way repeated-measures analysis of variance (α = 0.05). Only G20 fulfilled the temperature requirements at the surface (619 ± 21.8°C), at the underside (5.3 ± 1.4°C), and at the pulp (2.0 ± 1.0°C), and it caused no mineral phase change and significant reduction of enamel surface loss (-13.2 ± 4.0 µm) compared to C (-37.0 ± 10.1 µm, P < 0.05). A laser-scanning strategy (20 µs/2 kHz/1.25 J/cm², 3.4 mm/s) has been established that fulfilled the criteria for biological safety and significantly increased enamel erosion resistance (64%) in vitro.

Use of an optical clearing agent to enhance the visibility of subsurface structures and lesions from tooth occlusal surfaces

The purpose of this study is to show that optical clearing agents can be used to increase the visibility of deeply penetrating occlusal lesions that have reached the underlying dentin and spread laterally under the enamel. Previous studies have shown that high refractive index fluids can increase the contrast of caries lesions. Extracted teeth with natural occlusal lesions were imaged with optical coherence tomography (OCT) with and without the addition of a transparent vinyl polysiloxane impression material (VPS) currently used in vivo. The relative intensity of the reflectivity from the underlying lesion area for each sample was measured before and after application of the VPS. Lesion presence was confirmed with polarized light microscopy and microradiography. Application of VPS significantly increased (P < 0.0001) the integrated reflectivity of subsurface dentinal lesions. This study shows that optical clearing agents can be used to increase the optical penetration and the visibility of subsurface lesions and the dentinal–enamel junction under sound and demineralized enamel in OCT images.

Clinical monitoring of smooth surface enamel lesions using CP-OCT during nonsurgical intervention

INTRODUCTION

Studies have shown that cross-polarization optical coherence tomography (CP-OCT) can be used to image the internal structure of carious lesions in vivo. The objective of this study was to show that CP-OCT can be used to monitor changes in the internal structure of early active carious lesions on smooth surfaces during non-surgical intervention with fluoride.

METHODS

Lesions on the smooth surfaces of teeth were imaged using CP-OCT on 17 test subjects. Lesion structural changes were monitored during fluoride varnish application at 6-week intervals for 30 weeks. The lesion depth (L_d ), integrated reflectivity (ΔR), and surface zone thickness (S_z ) were monitored.

RESULTS

A distinct transparent surface zone that may be indicative of lesion arrestment was visible in CP-OCT images on 62/63 lesions before application of fluoride varnish. The lesion depth and internal structure were resolved for all the lesions. The overall change in the mean values for L_d , ΔR, and S_z for all the lesions was minimal and was not significant during the study (P > 0.05). Only 5/63 lesions manifested a significant increase in S_z during intervention.

CONCLUSION

Even though it appears that most of the lesions manifested little change with fluoride varnish application in the 30 weeks of the study, CP-OCT was able to measure the depth and internal structure of all the lesions including the thickness of the important transparent surface zone located at the surface of the lesions, indicating that CP-OCT is ideally suited for monitoring lesion severity in vivo. Lasers Surg. Med. 48:915-923, 2016. © 2016 Wiley Periodicals, Inc.

Enhancement of OCT images with vinyl polysiloxane (VPS)

Several studies have shown that optical coherence tomography (OCT) can be used to measure the remaining enamel thickness and detect the location of subsurface lesions hidden under the sound enamel. Moreover studies have shown that high refractive index liquids can be used to improve the visibility of subsurface lesions in OCT images. In this study, we demonstrate that vinyl polysiloxane (VPS) impression materials which are routinely used in dentistry can be used to enhance the detection of dentinal lesions on tooth occlusal surfaces. Lesion presence was confirmed with polarized light microscopy and microradiography.

Enamel Surface with Pit and Fissure Sealant Containing 45S5 Bioactive Glass

Enamel demineralization adjacent to pit and fissure sealants leads to the formation of marginal caries, which can necessitate the replacement of existing sealants. Dental materials with bioactive glass, which releases ions that inhibit dental caries, have been studied. The purpose of this study was to evaluate the enamel surface adjacent to sealants containing 45S5 bioactive glass (BAG) under simulated microleakage between the material and the tooth in a cariogenic environment. Sealants containing 45S5BAG filler were prepared as follows: 0% 45S5BAG + 50.0% glass (BAG0 group), 12.5% 45S5BAG + 37.5% glass (BAG12.5 group), 25.0% 45S5BAG + 25.0% glass (BAG25.0 group), 37.5% 45S5BAG + 12.5% glass (BAG37.5 group), and 50.0% 45S5BAG + 0% glass (BAG50.0 group). A cured sealant disk was placed over a flat bovine enamel disk, separated by a 60-µm gap, and immersed in lactic acid solution (pH 4.0) at 37 °C for 15, 30, and 45 d. After the storage period, each enamel disk was separated from the cured sealant disk, and the enamel surface was examined with optical 3-dimensional surface profilometer, microhardness tester, and scanning electron microscopy. The results showed a significant increase in roughness and a decrease in microhardness of the enamel surface as the proportion of 45S5BAG decreased (P< 0.05). In the scanning electron microscopy images, enamel surfaces with BAG50.0 showed a smooth surface, similar to those in the control group with distilled water, even after prolonged acid storage. Additionally, an etched pattern was observed on the surface of the demineralized enamel with a decreasing proportion of 45S5BAG. Increasing the 45S5BAG filler contents of the sealants had a significant impact in preventing the demineralization of the enamel surface within microgaps between the material and the tooth when exposed to a cariogenic environment. Therefore, despite some marginal leakage, these novel sealants may be effective preventive dental materials for inhibiting secondary caries at the margins.

Caries preventive measures in orthodontic practice: the development of a clinical practice guideline

OBJECTIVES

White spot lesions (WSLs) are a side effect of orthodontic treatment, causing esthetic problems and a risk of deeper enamel and dentine lesions. Many strategies have been developed for preventing WSLs, but great variability exists in preventive measures between orthodontists. This study developed statements on which a clinical practice guideline (CPG) can be developed in order to help orthodontists select preventive measures based on the best available evidence.

MATERIALS AND METHODS

A nominal group technique (RAND-e modified Delphi procedure) was used. A multidisciplinary expert panel rated 264 practice- and evidence-based statements related to the management of WSLs. To provide panel members with the same knowledge, a total of six articles obtained from a systematic review of the literature were read by the panel in preparation of three consensus rounds. According to the technique, a threshold of 75% of all ratings within any 3-point section of the 9-point scale regarding a specific statement was accepted as consensus.

RESULTS

After the first and second consensus rounds, consensus was reached on 37.5 and 31.1% of statements, respectively. For the remaining 31.4% of statements, consensus was reached during a 4-h consensus meeting.

CONCLUSIONS

Statements on the management of WSLs derived from a systematic literature review combined with expert opinion were formally integrated toward consensus through a nominal group technique. These statements formed the basis for developing a CPG on the management of WSLs before and during orthodontic treatment.

Comparison of Shear Bond Strength of New Self-etching Primer with Conventional Self-etching Primers: An In-vitro Study

BACKGROUND

In the past few years, there has been a major research drive to increase bond strength between dental materials and dental hard tissue and to reduce the associated demineralization around fixed orthodontic appliances. Thus, a recent approach is to incorporate an antibacterial agent into the primer to reduce the demineralization and enhance bond strength. The objective of this study was: (1) To evaluate the shear bond strength of orthodontic preadjusted edgewise appliance brackets bonded to extracted premolar teeth with antimicrobial self-etch primer (Reliance self-etching primer, Clearfil Protect Bond) and self-etching primer without antimicrobial agent (Clearfil SE bond). (2) To compare the mean shear bond strength values of the tested materials to conventional self-etching primer Transbond Plus.

MATERIALS AND METHODS

A total of 125 extracted human premolar teeth were randomly divided into five groups of 25 teeth each. Each sample was embedded in an acrylic block of polymethyl meth acrylate resin till coronal portion. Instron testing machine model LR LOYD 50 K was used for testing the shear bond strength of individual samples.

RESULTS

The results of the study showed that all five groups had adequate clinically acceptable bond strength. In intergroup comparison, there was statistically significant difference in bond strength of Reliance self-etching primer, Promt L pop, Clearfil Protect Bond, clearfil SE bond and Transbond Plus.

CONCLUSION

Reliance self-etching primer showed highest bond strength, followed by Clearfil Protect Bond, clearfil SE bond, and Transbond Plus. Clearfil Protect Bond primer containing methacryloxy dodecyl pyridium bromide have been demonstrated to kill Streptococcus mutans within a short time of contact and also exhibits an inhibitory effect on the growth of bacteria on its surface.

A prospective, randomized placebo-controlled clinical trial on the effects of a fluoride rinse on white spot lesion development and bleeding in orthodontic patients

Demineralizations around orthodontic brackets are a main disadvantage of orthodontic treatment. Several methods have been advocated to prevent their development, such as fluoride rinses or varnishes. In this randomized clinical trial, a fluoride rinse (a combination of sodium fluoride and amine fluoride) was compared with a placebo rinse, to be used every evening after toothbrushing. A total of 81 participants (mean age: 13.3 yr) completed the study (mean treatment period: 24.5 months). Demineralizations, measured using quantitative light‐induced fluorescence and the decayed, missing, and filled surfaces (DMFS) index, were assessed before treatment (baseline) and around 6 wk after debonding (post treatment). Bleeding scores were measured at baseline, and during and post treatment. The incidence rate ratio for demineralizations was 2.6 (95% CI: 1.1–6.3) in the placebo group vs. the fluoride group. In the fluoride group, 31% of participants developed at least one demineralization, compared with 47% in the placebo group. Relative to baseline, gingival bleeding increased significantly in the placebo group 1 yr after the start of treatment and onwards. For the fluoride group, bleeding scores during treatment were not different from those at baseline. In conclusion, using a fluoride rinse helps to maintain better oral health during fixed appliance treatment, resulting in fewer demineralizations.

Enhanced detection of dentinal lesions in OCT images using the RKT transformation

Several studies have shown that optical coherence tomography (OCT) can be used to measure the remaining enamel thickness and detect the location of subsurface lesions hidden under the sound enamel. The purpose of this study was to develop algorithms to enhance the visibility of subsurface structures such as hidden occlusal lesions and the dentinal-enamel junction. Extracted teeth with natural occlusal lesions were imaged with OCT with and without added high index fluids. A Rotating Kernel Transformation (RKT) nonlinear image processing filter was applied to PS-OCT images to enhance the visibility of the subsurface lesions under the sound enamel. The filter significantly increased (P<0.05) the visibility of the subsurface lesions.

Restoration materials and secondary caries using an in vitro biofilm model

This in vitro study investigated whether restoration materials and adhesives influence secondary caries formation in gaps using a short-term in vitro biofilm model. Sixty enamel-dentin blocks were restored with 6 different restoration materials with or without adhesives (n = 10 per group) with a gap: 1) Clearfil AP-X composite, 2) Clearfil AP-X composite + SE Bond, 3) Clearfil AP-X composite + ProtectBond, 4) Filtek Silorane composite, 5) Filtek Silorane composite + Silorane System adhesive, or 6) Tytin amalgam. Specimens were subjected to an intermittent 1% sucrose biofilm model for 20 days to create artificial caries lesions. Lesion progression in the enamel-dentin next to the different materials was measured in lesion depth (LD) and mineral loss (ML) using transversal wavelength independent microradiography (T-WIM). A regression analysis was used to compare the LD and ML of the different restoration materials at 4 measurement locations: 1 location at the surface of the enamel, 1 location at the wall of the enamel, and 2 locations at the wall of the dentin. A statistically significant effect of AP-X composite with Protect Bond was found for LD and ML at the WallDentin1 location, leading to less advanced wall lesions. An additional finding was that gap size was also statistically significant at the 2 wall locations in dentin, leading to increasing lesion progression with wider gaps. In conclusion, adhesives can influence wall lesion development in gaps. Protect Bond showed significantly less caries progression compared to bare restoration materials or other adhesives in this short-term in vitro biofilm model.

A method for monitoring enamel erosion using laser irradiated surfaces and optical coherence tomography

INTRODUCTION

Since optical coherence tomography (OCT) is well suited for measuring small dimensional changes on tooth surfaces, OCT has great potential for monitoring tooth erosion. Previous studies have shown that enamel areas ablated by a carbon dioxide laser manifested lower rates of erosion compared to the non-ablated areas. The purpose of this study was to develop a model to monitor erosion in vitro that could potentially be used in vivo.

METHODS

Thirteen bovine enamel blocks were used in this in vitro study. Each 10 mm × 2 mm block was partitioned into five regions, the central region was unprotected, the adjacent windows were irradiated by a CO2 laser operating at 9.3 µm with a fluence of 2.4 J/cm(2) , and the outermost windows were coated with acid resistant varnish. The samples were exposed to a pH cycling regimen that caused both erosion and subsurface demineralization for 2, 4 and 6 days. The surfaces were scanned using a time-domain polarization sensitive optical coherence tomography (PS-OCT) system and the degree of surface loss (erosion) and the integrated reflectivity with lesion depth was calculated for each window.

RESULTS

There was a large and significant reduction in the depth of surface loss (erosion) and the severity of demineralization in the areas irradiated by the laser.

CONCLUSION

Irradiation of the enamel surface with a pulsed carbon dioxide laser at sub-ablative intensities results in significant inhibition of erosion and demineralization under the acid challenge employed in this study. In addition, these results suggest that it may be feasible to modify regions of the enamel surface using the laser to serve as reference marks to monitor the rate of erosion in vivo.

Assessment of early occlusal caries pre- and post-sealant application--an imaging approach

BACKGROUND AND OBJECTIVE

Clinicians have difficulty assessing and monitoring early occlusal caries. Traditional clinical exam and radiographs are unable to detect the subtle alterations in enamel indicative of de- or re-mineralization, particularly under dental sealants. Although clinicians have used laser fluorescence (LF) to address this gap, this modality has demonstrated weak correlation with histology. The International Caries Detection and Assessment System (ICDAS-II) has demonstrated high sensitivity and specificity for caries detection, but since it is based on visual assessment, it is of no use in areas beneath the most commonly used dental sealants which are opaque. Optical coherence tomography (OCT) is an emergent assessment tool which has demonstrated great promise in detecting and quantifying caries, including areas beneath commonly used dental sealants and composites. However, OCT has not yet been widely integrated into clinical dental practice, perhaps because OCT imaging does not provide an easily accessible diagnostic outcome for clinicians. The objective of this ex vivo study was to use OCT-images of sound and carious occlusal surfaces in combination with a simple algorithm to compare the caries detection ability of OCT with tools clinicians may be more familiar with (LF and radiography), and with an established valid and reliable clinical assessment tool (ICDAS-II).

STUDY DESIGN/MATERIALS AND METHODS

One hundred twenty extracted teeth with sound or naturally carious occlusal surfaces were imaged with OCT, LF, radiography, and examined clinically with the ICDAS-II. Teeth were randomized to one of two dental sealants recommended for use with LF. A novel simple algorithm was used to interpret OCT-based images. The accuracy of caries severity assessments of the OCT-based diagnosis, LF, ICDAS-II, and digital radiography were compared to the 4-point histological analysis gold standard.

RESULTS

OCT and ICDAS-II caries severity assessments demonstrated high sensitivity (94.0%; 92.3%) and specificity (85.0%; 83.3%), LF demonstrated low sensitivity (65.2%) but high specificity (97.6%), and digital radiography demonstrated low sensitivity (67.1%) with moderate specificity (79.5%) on unsealed occlusal surfaces. OCT-based caries severity assessments of sealed teeth demonstrated high specificity (97.6%), sensitivity (89.9%), excellent positive predictive value (98.6%), and negative predictive value (83.3%). Despite our use of LF recommended dental sealants, in the presence of sealants, LF assessment of caries severity demonstrated high sensitivity (95.1%), but extremely low specificity (10.3%), positive predictive value (68.8%), and negative predictive value (50.0%).

CONCLUSION

This study found that OCT-based imaging combined with a simple diagnostic algorithm accurately assessed the severity of natural early caries on occlusal surfaces in extracted teeth both in the absence and presence of dental sealant. The findings of this study support the clinical use of OCT imaging for assessment and monitoring progression of early non-cavitated caries lesions on occlusal surfaces including areas under dental sealants.

Enhancing the detection of hidden occlusal caries lesions with OCT using high index liquids

In a previous study, we investigated the influence of several high refractive index fluids on the performance of polarization sensitive optical coherence tomography (PS-OCT). That study showed that these liquids can increase the effective imaging depth and lesion contrast. Other in vitro and in vivo studies have shown that OCT can be used to show whether occlusal lesions have penetrated to the dentinal-enamel junction (DEJ) and spread laterally under the enamel. The purpose of this study was to determine if high index fluids can enhance the ability of OCT to detect hidden occlusal lesions and show if these lesions have penetrated through the enamel into the underlying dentin. Ten extracted teeth with occlusal lesions were imaged using OCT after the application of water, glycerol, BABB (33% Benzyl Alcohol + 67% Benzyl Benzoate) and a Cargille Liquid (Cedar Grove, NJ) (hydrogenated terphenyl 1-bromo-naphthalene) with a refractive index of 1.61. The intensity of the reflectance from the underlying lesion area for each sample was compared with the reflectance of the sound tooth surface for each fluid. The use of high index fluids significantly (P< 0.0001) increased the reflectivity of subsurface occlusal lesions under the surrounding sound enamel.