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Dental Materials Journal Jun 2024This study investigates the effects of dentin's drying time, roughness, and curing modes of resin cement on bond strength. Forty human teeth were divided into eight...
This study investigates the effects of dentin's drying time, roughness, and curing modes of resin cement on bond strength. Forty human teeth were divided into eight groups based on three experimental factors: dentin's roughness by 240-or 600-grit SiC paper (coarse or fine), dentin wetness with air-drying time (5-s or 10-s), and Single Bond Universal adhesive's curing mode by co-curing with RelyX Ultimate cement or light-curing separately (co-curing or light-curing). The micro-tensile bond strength of fifteen resin-dentin stikcs per groups was measured. Failure mode and adhesive layers were observed using stereoscopic and confocal laser scanning microscopy, respectively. The curing mode of the adhesive layer affected the bond strength of the dentin-resin cement (p<0.05). In particular, the light-curing mode exhibited a significantly higher bond strength than the co-curing one (p<0.05). The bond strength between the resin cement and dentin was improved in the 5-s drying groups than in the 10-s drying groups.
Topics: Humans; Dentin; Surface Properties; Resin Cements; Tensile Strength; Dental Bonding; Materials Testing; Dentin-Bonding Agents; Microscopy, Confocal; Bisphenol A-Glycidyl Methacrylate; Dental Stress Analysis; Light-Curing of Dental Adhesives; Time Factors
PubMed: 38719583
DOI: 10.4012/dmj.2023-287 -
Oral Health & Preventive Dentistry Sep 2020To investigate dentin abrasivity and cleaning efficacy of novel/alternative toothpastes containing diamond particles, active carbon, sea salt or organic oils.
PURPOSE
To investigate dentin abrasivity and cleaning efficacy of novel/alternative toothpastes containing diamond particles, active carbon, sea salt or organic oils.
MATERIALS AND METHODS
Seventy-two bovine dentin samples (for measuring abrasivity) and 60 human dentin samples (for assessing cleaning efficacy) were used in this study. Samples were divided into six groups as follows: group 1: Elmex Kariesschutz (hydrated silica); group 2: Lavera Neutral Zahngel (sea salt); group 3: Curaprox Black is White (active carbon); group 4: Swiss Smile Diamond Glow (diamond powder); group 5: Ringana Fresh Tooth Oil (hydrated silica); and group 6: artificial saliva. Samples were brushed for a total of 26 min at 120 strokes/min, replacing slurries (1 part respective toothpaste and 2 parts artificial saliva) every 2 min. Finally, abrasive dentin wear was measured profilometrically and cleaning efficacy planimetrically.
RESULTS
The highest abrasivity values were observed for Lavera Neutral Zahngel (sea salt 9.2 µm) and Elmex Kariesschutz group (hydrated silica 6.0 µm). The lowest abrasivity value was observed for Ringana Fresh Tooth Oil group (hydrated silica 1.3 µm). The highest cleaning efficacy was observed for Elmex Kariesschutz group (86.7%) and the lowest cleaning efficacy was observed for Ringana Fresh Tooth Oil group (31.3%).
CONCLUSION
The addition of diamond powder or active carbon to toothpastes could offer high cleaning efficacy with low dentin abrasivity. The addition of sea salt to traditional abrasives might cause high abrasive dentin wear without adding further cleaning benefit.
Topics: Animals; Cattle; Dentin; Humans; Saliva, Artificial; Tooth Abrasion; Toothbrushing; Toothpastes
PubMed: 32895654
DOI: 10.3290/j.ohpd.a45074 -
BMC Oral Health Nov 2022Dentin hypersensitivity is a painful response to external stimuli applied to exposed dentinal tubules. Various toothpastes with active desensitizing ingredients for the...
BACKGROUND
Dentin hypersensitivity is a painful response to external stimuli applied to exposed dentinal tubules. Various toothpastes with active desensitizing ingredients for the relief of dentin hypersensitivity are commercially available. However, data from several studies suggest that the effects of desensitizing toothpastes are unstable and brief. This study aimed to investigate the effect of toothpastes containing CPNE7-derived oligopeptide (CPNE7-DP) and other active desensitizing ingredients in the dentin microleakage, tubule occlusion and tertiary dentin formation.
METHODS
Using scanning electron microscopy (SEM), we evaluated the patency of dentinal tubules on the surface of human dentin disks after brushing experiments with the various toothpastes. Dentin was histologically evaluated in a hypersensitivity model of canine teeth, after the exposed dentin area was brushed for 6 weeks. The toothpaste used in group 1 (control) did not contain any desensitizing ingredients; that used in group 2 contained CPNE7-DP; Colgate Sensitive was used in group 3; and Sensodyne Rapid Relief was used in group 4. Finally, we conducted microleakage analysis to investigate the dentin sealing effect. The microleakage analysis data were subjected to one-way ANOVA and post-hoc Tukey tests (alpha = 0.05).
RESULTS
In the SEM images, all four groups of teeth exhibited partial occlusion of the dentinal tubules on the tooth surface. In the in vivo hypersensitivity model, group 2 exhibited a newly formed tertiary dentin, whereas no new hard tissue formation was observed in groups 1, 3, and 4. Microleakage analysis revealed that the volume of dentinal fluid flow was significantly smaller in group 2 than in group 1.
CONCLUSIONS
These results indicate that CPNE7-DP is a promising active ingredient with long-term dentin sealing effects.
Topics: Humans; Toothpastes; Dentin Sensitivity; Dentin; Toothbrushing; Sodium Fluoride; Microscopy, Electron, Scanning
PubMed: 36368979
DOI: 10.1186/s12903-022-02558-8 -
Dental Materials : Official Publication... Nov 2021To elucidate the structure-activity relationships (SARs) of proanthocyanidins (PACs) with type I collagen using sixteen chemically defined PACs with degree of...
OBJECTIVE
To elucidate the structure-activity relationships (SARs) of proanthocyanidins (PACs) with type I collagen using sixteen chemically defined PACs with degree of polymerization (DP) 2-6.
METHODS
Under a dentin model, the biomimicry of PACs with type I collagen was investigated by dynamic mechanical analysis (DMA) and infrared spectroscopy. The dentin matrix was modified with PACs from Pinus massoniana [monomers (Mon-1 and Mon-2), dimers (Dim-1-Dim-4), trimers (Tri-1-Tri-4), tetramers (Tet-1-Tet-5), and hexamer (Hex-1)]. A strain sweep method in a 3-point bending submersion clamp was used to assess the viscoelastic properties [storage (E'), loss (E"), and complex moduli (E*) and tan δ] of the dentin matrix before and after biomodification. Biochemical analysis of the dentin matrix was assessed with FTIR spectroscopy. Data were statistically analyzed using one-way ANOVA and post-hoc tests (α = 0.05).
RESULTS
DP had a significant effect on modified dentin moduli (tetramers ≈ trimers > hexamers ≈ dimers > monomers ≈ control, p < 0.001). Trimers and tetramers yielded 6- to 8-fold increase in the mechanical properties of modified dentin and induced conformational changes to the secondary structure of collagen. Modifications to the tertiary structure of collagen was shown in all PAC modified-dentin matrices.
SIGNIFICANCE
Findings establish three key SARs: (i) increasing DP generally enhances biomimicry potential of PACs in modulating the mechanical and chemical properties of dentin (ii) the secondary structure of dentin collagen is affected by the position of B-type inter-flavanyl linkages (4β → 6 and 4β → 8); and (iii) the terminal monomeric flavan-3-ol unit plays a modulatory role in the viscoelasticity of dentin.
Topics: Collagen; Dentin; Proanthocyanidins; Structure-Activity Relationship
PubMed: 34563363
DOI: 10.1016/j.dental.2021.08.013 -
Journal of Biomedical Materials... Nov 2019Nearly 100 million of the 170 million composite and amalgam restorations placed annually in the United States are replacements for failed restorations. The primary... (Review)
Review
Nearly 100 million of the 170 million composite and amalgam restorations placed annually in the United States are replacements for failed restorations. The primary reason both composite and amalgam restorations fail is recurrent decay, for which composite restorations experience a 2.0-3.5-fold increase compared to amalgam. Recurrent decay is a pernicious problem-the standard treatment is replacement of defective composites with larger restorations that will also fail, initiating a cycle of ever-larger restorations that can lead to root canals, and eventually, to tooth loss. Unlike amalgam, composite lacks the inherent capability to seal discrepancies at the restorative material/tooth interface. The low-viscosity adhesive that bonds the composite to the tooth is intended to seal the interface, but the adhesive degrades, which can breach the composite/tooth margin. Bacteria and bacterial by-products such as acids and enzymes infiltrate the marginal gaps and the composite's inability to increase the interfacial pH facilitates cariogenic and aciduric bacterial outgrowth. Together, these characteristics encourage recurrent decay, pulpal damage, and composite failure. This review article examines key biological and physicochemical interactions involved in the failure of composite restorations and discusses innovative strategies to mitigate the negative effects of pathogens at the adhesive/dentin interface. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2466-2475, 2019.
Topics: Adhesives; Dental Materials; Dental Restoration, Permanent; Dentin; Humans
PubMed: 30895695
DOI: 10.1002/jbm.b.34358 -
Dental Materials : Official Publication... Sep 2019To investigate the effect of an experimental biomimetic mineralization kit (BIMIN) on the chemical composition and crystallinity of caries-free enamel and dentin samples...
OBJECTIVE
To investigate the effect of an experimental biomimetic mineralization kit (BIMIN) on the chemical composition and crystallinity of caries-free enamel and dentin samples in vitro.
METHODS
Enamel and dentin samples from 20 human teeth (10 for enamel; 10 for dentin) were divided into a control group without treatment and test samples with BIMIN treatment. Quantitative analysis of tissue penetration of fluoride, phosphate, and calcium was performed using energy-dispersive X-ray spectroscopy (EDX). Mineralization depth was measured by Raman spectroscopy probing the symmetric valence vibration near 960cm as a marker for crystallinity. EDX data was statistically analyzed using a paired t-test and Raman data was analyzed using the Student's t-test.
RESULTS
EDX analysis demonstrated a penetration depth of fluoride of 4.10±3.32μm in enamel and 4.31±2.67μm in dentin. Calcium infiltrated into enamel 2.65±0.64μm and into dentin 5.58±1.63μm, while the penetration depths for phosphate were 4.83±2.81μm for enamel and 6.75±3.25μm for dentin. Further, up to 25μm of a newly mineralized enamel-like layer was observed on the surface of the samples. Raman concentration curves demonstrated an increased degree of mineralization up to 5-10μm into the dentin and enamel samples.
SIGNIFICANCE
Biomimetic mineralization of enamel and dentin samples resulted in an increase of mineralization and a penetration of fluoride into enamel and dentin.
Topics: Biomimetics; Dental Enamel; Dentin; Fluorides; Humans; Tooth
PubMed: 31208774
DOI: 10.1016/j.dental.2019.05.025 -
Dental Materials : Official Publication... Dec 2022The aim was to investigate shear bond strengths and failure modes of four self-etch bonding agents to bovine dentin and enamel and to compare evaluation of data sets...
OBJECTIVES
The aim was to investigate shear bond strengths and failure modes of four self-etch bonding agents to bovine dentin and enamel and to compare evaluation of data sets with or without exclusion of cohesive failure specimens.
METHODS
Composite-cylinders were bonded perpendicularly to bovine dentin and enamel surfaces. Shear-strengths were measured 24 h post-bonding of: Scotchbond Universal® (SBU, 3 M), OptiBond™ XTR (OBXTR, Kerr), OptiBond™ universal (OBU, KaVo-Kerr) and Prime & Bond active® (PBA, Dentsply-Sirona). Analysis of overall data was made via a linear mixed-model. This was repeated after exclusion of specimens associated with cohesive failures.
RESULTS
When both adhesive and cohesive failures were considered, OBU and OBXTR showed comparable dentin and enamel bond strengths, whereas lower strengths were found on enamel for SBU (p < 0.001) and PBA (p = 0.015). For OBXTR higher shear strengths were measured for specimens associated with cohesive failures. When cohesive failures were excluded, the majority of shear bond strengths of adhesive failure specimens were only slightly different from overall results. However, uniquely with OBXTR dramatically lower shear bond strengths were found for dentin substrate.
SIGNIFICANCE
After exclusion of cases with cohesive failures OBXTR adhesive fell behind other materials in the sequence of average shear strengths. This did not reflect the actual performance of the material. Therefore, in statistical analysis we do not recommend exclusion of data based on a specific fracture mode.
Topics: Cattle; Animals; Dentin-Bonding Agents; Dental Bonding; Dentin; Dental Cements; Materials Testing; Resin Cements; Shear Strength; Composite Resins
PubMed: 36347654
DOI: 10.1016/j.dental.2022.10.003 -
Dental Materials : Official Publication... Dec 2021To evaluate the effects of different polyphenols and solvents on dentin collagen's crosslinking interactions and biostabilization against MMPs and collagenase...
OBJECTIVE
To evaluate the effects of different polyphenols and solvents on dentin collagen's crosslinking interactions and biostabilization against MMPs and collagenase degradation.
METHODS
Two polyphenols [proanthocyanidin (PA) and quercetin (QC)] with different water solubility were prepared as treatment solutions using ethanol (EtOH) or dimethyl sulfoxide (DMSO) as solvents. 6-um-thick dentin films were microtomed from dentin slabs of third molars. Following demineralization, films or slabs were subject to 60-s treatment (PA or QC) or no treatment (control) with subsequent extended-rinse with original solvent (EtOH or DMSO) or distilled water (DW). Collagen crosslinking interactions were assessed by FTIR. Biostability was assessed through endogenous MMPs activity via confocal laser scanning microscopy, and exogenous collagenase degradation via weight loss, hydroxyproline release and SEM. Finally, direct collagenase inactivation was also evaluated. Data were analyzed by three-way ANOVA and post-hoc tests (α=0.05%).
RESULTS
Distinct effects of two polyphenols and solvents on collagen crosslinking and biostabilization were observed. Higher crosslinking and biostability efficacy occurred with PA than QC (p<0.001) that demonstrated negligible collagen interactions. With DMSO solvent, efficacy results were significantly reduced with both polyphenols (p<0.05). DMSO-rinse further weakened interactions of PA with collagen, diminishing biostability (p<0.05). Low biostability was detected with QC and DW-rinse, suggesting direct enzymatic inhibition due to physical presence in collagen.
SIGNIFICANCE
Collagen crosslinking interactions and biostability depend on polyphenol chemical characteristics. Treatment-solution solvents may affect interactions between polyphenols and collagen, specifically, DMSO showed detrimental effects on collagen crosslinking and biostability and should be used with caution.
Topics: Collagen; Dental Bonding; Dentin; Dentin-Bonding Agents; Polyphenols; Solvents; Tensile Strength
PubMed: 34579958
DOI: 10.1016/j.dental.2021.09.009 -
Journal of Dentistry Aug 2021To evaluate obliterating capability and biological performance of desensitizing agents.
OBJECTIVES
To evaluate obliterating capability and biological performance of desensitizing agents.
METHODS
50 dentin blocks were distributed according to the desensitizing agent used (n = 10): Control (Artificial saliva); Ultra EZ (Ultradent); Desensibilize Nano P (FGM); T5-OH Bioactive Glass (Experimental solution); F18 Bioactive Glass (Experimental solution). Desensitizing treatments were performed for 15 days. In addition, specimens were subjected to acid challenge to simulate oral environment demineralizing conditions. Samples were subjected to permeability analysis before and after desensitizing procedures and acid challenge. Cytotoxicity analysis was performed by using Alamar Blue assay and complemented by total protein quantification by Pierce Bicinchoninic Acid assay at 15 min, 24-h and 48-h time points. Scanning electron microscopy and energy dispersion X-ray spectroscopy were performed for qualitative analysis. Data of dentin permeability was analyzed by two-way repeated measures ANOVA and Tukey's test. For cytotoxicity, Kruskal-Wallis and Newman-Keuls tests.
RESULTS
for dentin permeability there was no significant difference among desensitizing agents after treatment, but control group presented highest values (0.131 ± 0.076 Lp). After acid challenge, control group maintained highest values (0.044 ± 0.014 Lp) with significant difference to other groups, except for Desensibilize Nano P (0.037 ± 0.019 Lp). For cytotoxicity, there were no significant differences among groups.
CONCLUSION
Bioglass-based desensitizers caused similar effects to commercially available products, regarding permeability and dentin biological properties.
CLINICAL SIGNIFICANCE
There is no gold standard protocol for dentin sensitivity. The study of novel desensitizing agents that can obliterate dentinal tubules in a faster-acting and long-lasting way may help meet this clinical need.
Topics: Dentin; Dentin Desensitizing Agents; Dentin Permeability; Dentin Sensitivity; Humans; Microscopy, Electron, Scanning; Permeability; Saliva, Artificial; Spectrometry, X-Ray Emission
PubMed: 34118283
DOI: 10.1016/j.jdent.2021.103719 -
PLoS Pathogens May 2024The role of bacteria in the etiology of dental caries is long established, while the role of fungi has only recently gained more attention. The microbial invasion of...
The role of bacteria in the etiology of dental caries is long established, while the role of fungi has only recently gained more attention. The microbial invasion of dentin in advanced caries especially merits additional research. We evaluated the fungal and bacterial community composition and spatial distribution within carious dentin. Amplicon 16S rRNA gene sequencing together with quantitative PCR was used to profile bacterial and fungal species in caries-free children (n = 43) and 4 stages of caries progression from children with severe early childhood caries (n = 32). Additionally, healthy (n = 10) and carious (n = 10) primary teeth were decalcified, sectioned, and stained with Grocott's methenamine silver, periodic acid Schiff (PAS) and calcofluor white (CW) for fungi. Immunolocalization was also performed using antibodies against fungal β-D-glucan, gram-positive bacterial lipoteichoic acid, gram-negative endotoxin, Streptococcus mutans, and Candida albicans. We also performed field emission scanning electron microscopy (FESEM) to visualize fungi and bacteria within carious dentinal tubules. Bacterial communities observed included a high abundance of S. mutans and the Veillonella parvula group, as expected. There was a higher ratio of fungi to bacteria in dentin-involved lesions compared to less severe lesions with frequent preponderance of C. albicans, C. dubliniensis, and in one case C. tropicalis. Grocott's silver, PAS, CW and immunohistochemistry (IHC) demonstrated the presence of fungi within carious dentinal tubules. Multiplex IHC revealed that fungi, gram-negative, and gram-positive bacteria primarily occupied separate dentinal tubules, with rare instances of colocalization. Similar findings were observed with multiplex immunofluorescence using anti-S. mutans and anti-C. albicans antibodies. Electron microscopy showed monomorphic bacterial and fungal biofilms within distinct dentin tubules. We demonstrate a previously unrecognized phenomenon in which fungi and bacteria occupy distinct spatial niches within carious dentin and seldom co-colonize. The potential significance of this phenomenon in caries progression warrants further exploration.
Topics: Humans; Dental Caries; Dentin; Male; Child; Female; Child, Preschool; Bacteria; Fungi; RNA, Ribosomal, 16S
PubMed: 38805482
DOI: 10.1371/journal.ppat.1011865