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BioMed Research International 2017This study investigated the effect of benzalkonium chloride (BAC) modification of two adhesive systems on long-term bond strength to normal and artificially eroded...
This study investigated the effect of benzalkonium chloride (BAC) modification of two adhesive systems on long-term bond strength to normal and artificially eroded dentin. A total of 128 extracted human molars were sectioned and the buccal and oral surfaces of each molar were ground until the dentin. One half was left untreated (normal dentin) while the other half underwent artificial erosion. Resin composite was bonded to the buccal or oral surface following treatment with Adper Scotchbond 1XT or OptiBond FL without or with 1% BAC incorporation. Shear bond strength (SBS) was measured after 24 h (100% humidity, 37°C) or 1 year (tap water, 37°C). SBS results were statistically analyzed ( = 0.05). SBS was significantly lower to artificially eroded dentin than to normal dentin ( < 0.001). Storage for 1 year had no effect on SBS to normal dentin but led to a significant decrease in SBS to artificially eroded dentin ( < 0.001). BAC incorporation decreased the 24 h SBS to normal dentin ( = 0.018), increased the 24 h SBS to eroded dentin ( = 0.001), and had no effect on the 1-year SBS for either substrate. Consequently, BAC incorporation did not improve bond durability.
Topics: Benzalkonium Compounds; Dental Bonding; Dental Materials; Dental Stress Analysis; Dentin; Humans; Shear Strength; Tooth Erosion
PubMed: 28875148
DOI: 10.1155/2017/1207208 -
Journal of Endodontics May 2005The effect of three dentin contacting materials on three-dimensional cultures of pulp-derived cells was evaluated in a dentin barrier test device. The test materials...
The effect of three dentin contacting materials on three-dimensional cultures of pulp-derived cells was evaluated in a dentin barrier test device. The test materials (Syntac Classic, Prompt L-Pop, Vitrebond) were applied on dentin disks of different thicknesses ranging from 100 to 500 microm. After 24 h of exposure with and without perfusion of the test chamber, cell survival was evaluated using the MTT assay and related to a nontoxic control material. Syntac Classic decreased cell activity significantly (p = 0.0003), independently of the dentin thickness. For Prompt L-Pop and Vitrebond a significant influence of dentin thickness was found on the cell reaction. After exposure of the control material, photometric readings showed no dependency of the cellular reaction on dentin thickness (p > 0.05). It could be demonstrated that dentin acts as a barrier, decreasing the elicited cytotoxicity with increasing thickness. This effect is material related, showing little influence for the nontoxic or the glutaraldehyde containing material.
Topics: Animals; Cattle; Cell Survival; Cells, Cultured; Dental Pulp; Dentin; Dentin Permeability; Dentin-Bonding Agents; Diffusion Chambers, Culture; Glass Ionomer Cements; Materials Testing; Resin Cements
PubMed: 15851937
DOI: 10.1097/01.don.0000145428.26880.e5 -
Clinical Oral Investigations Nov 2018Post-radiation dental lesions affect mainly the cervical area of the tooth. Until now, there are quite few evidences regarding the effects of radiation exposure on root...
OBJECTIVES
Post-radiation dental lesions affect mainly the cervical area of the tooth. Until now, there are quite few evidences regarding the effects of radiation exposure on root dentin breakdown. To better understand this effect, we used human root dentin specimens obtained from third molars from similarly aged individuals.
MATERIALS AND METHODS
Twenty specimens were analyzed by the surface hardness (SH), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) to evaluate the baseline properties of their root dentin. Other six human teeth were prepared and analyzed by scanning electron microscopy (SEM). Then the specimens were randomly distributed between two groups (n = 13 per group) and irradiated with a total dose of 55 or 70 Gy in a linear accelerator. The percentage of EDX and surface hardness loss (%SHL) were determined based on measurements before and after irradiation. The specimens were also analyzed after irradiation by SEM and XRD. The Ca/P weight ratio was calculated.
RESULTS
Based on SEM analysis, radiation exposure induced dehydration of the dentin. The Ca/P weight ratio decreased (p = 0.0045). The %SHL of specimens irradiated with 70 Gy was higher than that of the 55-Gy group (p < 0.05), although even the lower dose induced root dentin breakdown.
CONCLUSIONS
Overall, we can state that radiation exposure changes the composition and structure of human root dentin, which detrimentally affect its hardness.
CLINICAL RELEVANCE
The changes reported herein might influence the selection of the dental materials and will bring new knowledge in this field to prevent radiation-related caries in root dentin.
Topics: Dentin; Hardness; Humans; In Vitro Techniques; Microscopy, Electron, Scanning; Molar, Third; Spectrometry, X-Ray Emission; Tooth Root; X-Ray Diffraction
PubMed: 29430611
DOI: 10.1007/s00784-018-2373-6 -
Australian Dental Journal Sep 2015Carious affected dentine (CAD) represents a very common substrate in adhesive dentistry. Despite its ability to interact with adhesive systems, the intrinsic character... (Review)
Review
BACKGROUND
Carious affected dentine (CAD) represents a very common substrate in adhesive dentistry. Despite its ability to interact with adhesive systems, the intrinsic character of CAD leads to lower bonding compared with sound dentine, regardless of the adhesive systems used. This low bonding may be more susceptible to leakage and hydrolysis of the interface by matrix metalloproteinases (MMPs). This systematic review aimed to determine current knowledge of CAD bonding, together with bond strength and MMP inhibitors' ability to prevent hybrid layer instability.
METHODS
MEDLINE/Pubmed, Scopus and The Cochrane Library databases were electronically searched for articles published from 1 January 1960 to 31 August 2014. Two reviewers independently screened and included papers according to predefined selection criteria.
RESULTS
The electronic searches identified 320 studies. After title, abstract and full-text examinations, 139 articles met the inclusion criteria. Data highlighted that a poor resin saturation of the already demineralized collagen matrix in CAD is strictly related to nanoleakage in interdiffusion and is the basis of the progressive decrease in strength with hydrolysis by MMPs. The use of mild self-etching systems seems to be the more accredited method to establish bonding in CAD. Inhibitors of MMPs may ensure better performance of CAD bonding, allowing undisturbed remineralization of the affected matrix.
CONCLUSIONS
CAD bonding needs further understanding and improvement, particularly to enhance the strength and durability of the hybrid layer.
Topics: Dental Bonding; Dental Caries; Dental Cements; Dental Leakage; Dentin; Humans; Matrix Metalloproteinase Inhibitors; Stress, Mechanical
PubMed: 25790344
DOI: 10.1111/adj.12309 -
PloS One 2017Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials for drug delivery and mineralization induction. They can load silver and exhibit...
Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials for drug delivery and mineralization induction. They can load silver and exhibit significantly antibacterial effects. However, the effects of MCSNs and silver-loaded MCSNs on dentin are unknown. The silver (Ag) and/or zinc (Zn) incorporated MCSNs (Ag-Zn-MCSNs) were prepared by a template method, and their characterizations were tested. Then the nanoparticles were filled into root canals and their effects on the dentin were investigated. Ag-Zn-MCSNs showed characteristics of mesoporous materials and sustained release of ions over time. Ag-Zn-MCSNs adhered well to the root canal walls and infiltrated into the dentinal tubules after ultrasound activation. Ag-Zn-MCSNs showed no significantly negative effects on either the flexural strength or the modulus of elasticity of dentin, while CH decreased the flexural strength of dentin significantly (P<0.05). These findings suggested that Ag and Zn can be incorporated into MCSNs using a template method, and the Ag-Zn-MCSNs may be developed into a new disinfectant for the root canal and dentinal tubules.
Topics: Biocompatible Materials; Biomechanical Phenomena; Calcium Compounds; Dentin; Humans; Hydrogen-Ion Concentration; Mechanical Phenomena; Nanoparticles; Porosity; Silicates; Silver; Zinc
PubMed: 28787004
DOI: 10.1371/journal.pone.0182583 -
Critical Reviews in Biomedical... 2021One aspect of special concern in endodontics is the effect of irrigating solutions on the biomechanical properties of dentine. A systematic review of in vitro studies... (Meta-Analysis)
Meta-Analysis
One aspect of special concern in endodontics is the effect of irrigating solutions on the biomechanical properties of dentine. A systematic review of in vitro studies was conducted to analyze and systematize the effect of endodontic irrigating solutions on biomechanical properties in noninstrumented dentine, according to published in vitro studies. A literature review was conducted on different databases including papers from 2009 to 2019. Two researchers identified in vitro studies on permanent teeth root dentine that reported control group, featured nonmechanical preparation, and sample size ≥ 10. An instrument was designed for bias assessment in three categories (High-Uncertain-Low), applying 17 criteria. Using the PRISMA tool, an electronic search found 9,026 titles. From these, 28 were subjected to full-text analysis and 9 were chosen for qualitative analysis. It was identified that chelates decrease microhardness and stiffness. It was also inferred that the proteolytic effect of NaOCl reduces the elasticity modulus and flexural strength. The heterogeneity analysis, with a value I2:92% for microhardness and I2:81% for roughness, revealed high heterogeneity among the included studies. The random effect model identified with 95% confidence that NaOCl and EDTA significantly decrease microhardness: -3.00[-4.22, -1.78]; EDTA 17% at 15 min being on average the lowest value: -6.66[-8.32, -5.00]. For roughness, all the proposed solutions increased significantly: 2.37[1.67, 3.08]; the highest, 3.94[2.84, 5.04], was recorded by NaOCl2.5%-15 min. In contrast, CLX registered a high roughness value: 3.33[1.88, 4.77]. Dentinal microhardness reduction associated to chelates is a concentration and time- dependent variable. Collagen degradation by NaOCl is a time and concentration-dependent variable.
Topics: Dentin; Humans; Root Canal Irrigants; Sodium Hypochlorite
PubMed: 34936315
DOI: 10.1615/CritRevBiomedEng.2021038065 -
Journal of Biomedical Optics May 2015The aim of this study was to evaluate the surface roughness and wettability of dentin following ultrashort pulsed laser ablation with different levels of fluence and...
The aim of this study was to evaluate the surface roughness and wettability of dentin following ultrashort pulsed laser ablation with different levels of fluence and pulse overlap (PO). Twenty-five extracted human teeth crowns were cut longitudinally into slices of approximately 1.5-mm thick and randomly divided into nine groups of five. Samples in groups 1 to 8 were ablated with an ultrashort pulsed laser through a galvanometric scanning system. Samples in group 9 were prepared using a mechanical rotary instrument. The surface roughness of samples from each group was then measured using a three-dimensional profile measurement laser microscope, and wettability was evaluated by measuring the contact angle of a drop of water on the prepared dentin surface using an optical contact angle measuring device. The results showed that both laser fluence and PO had an effect on dentin surface roughness. Specifically, a higher PO decreased dentin surface roughness and reduced the effect of high-laser fluence on decreasing the surface roughness in some groups. Furthermore, all ablated dentin showed a contact angle of approximately 0 deg, meaning that laser ablation significantly improved wettability. Adjustment of ultrashort pulsed laser parameters can, therefore,significantly alter dentin surface roughness and wettability.
Topics: Dentin; Dose-Response Relationship, Radiation; Humans; In Vitro Techniques; Laser Therapy; Lasers; Light; Radiation Dosage; Tooth Preparation, Prosthodontic; Wettability
PubMed: 26018789
DOI: 10.1117/1.JBO.20.5.055006 -
Dental Materials : Official Publication... Sep 2002The aim of this study was to investigate the creep, stress relaxation and strain rate behavior of human root dentin under compressive loading.
OBJECTIVES
The aim of this study was to investigate the creep, stress relaxation and strain rate behavior of human root dentin under compressive loading.
METHODS
Cylindrical root dentin samples of 3.5mm outer diameter, 1.5mm internal canal diameter and 6-10mm long were prepared from freshly extracted teeth. The samples were tested in a closed-loop servohydraulic testing machine at constant load or displacement, and varied strain rate. In vivo strain rates were estimated using strain gauges bonded to human teeth.
RESULTS
A family of creep curves, determined at different loads within dentin's elastic region, was found to be consistent with a material having linear viscoelastic behavior. A positive correlation (r(2)=0.79, P<0.001) was found between creep rate and stress. Young's modulus (E) was found to be a function of the strain rate with rates of loading in the range 10-500,000Ns(-1). Loading at constant displacement showed stress to be a decreasing function of time (i.e. stress relaxation).
SIGNIFICANCE
Dentin showed linear-viscoelastic behavior under various conditions of compressive loading. Time dependent properties of dentin should be taken into account in restorative dentistry.
Topics: Algorithms; Biomechanical Phenomena; Bite Force; Candy; Dental Stress Analysis; Dentin; Elasticity; Humans; Mastication; Nuts; Paraffin; Statistics as Topic; Stress, Mechanical; Time Factors; Tooth Root; Viscosity; Weight-Bearing
PubMed: 12098578
DOI: 10.1016/s0109-5641(01)00074-4 -
Archives of Oral Biology Apr 2020The aim of this study was to evaluate the efficiency of xylitol chewing gums enriched with propolis, remineralizing softly demineralized dentin in vitro.
OBJECTIVES
The aim of this study was to evaluate the efficiency of xylitol chewing gums enriched with propolis, remineralizing softly demineralized dentin in vitro.
DESIGN
Four groups of chewing gum were developed; Group1: xylitol (1.8 %), Group2: xylitol + casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (3%), Group3: xylitol+Hydroxyapatite (3%) and Group4: xylitol + propolis (5%). A control group was designed without chewing gum, but with artificial saliva. Sections of embedded crowns and cleaned roots of twenty five bovine incisors were demineralized in carbonated drink. Crown specimens were half-varnished. Remineralization process was run for all the dental specimens in the 4 groups with gum extracts and in the control group with artificial saliva for 20 min at 37 °C three times a day during 7 days. Mineral contents were evaluated by scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX-SEM). Surface morphology and roughness were analyzed using atomic force microscopy (AFM). Micro-hardness was measured using Vickers micro-hardness tester among varnished and unvarnished sides.
RESULTS
Calcium/Phosphate mean ratio showed a significant decrease between the control group, group1, group2 and group4. Control group and group3 were not significantly different. Micro-hardness increased significantly for all treated groups. AFM showed obstruction of dentinal tubules in all the groups and roughness decreased in the treated side of the dentin compared to the untreated side for tested groups.
CONCLUSION
Xylitol chewing gum enriched with propolis showed dentinal tubules occlusion, significant improvement of micro-hardness and slight decrease in roughness. Ca/P ratio analysis suggests that a mineral compound other than hydroxyapatite is responsible of tubules occlusion.
Topics: Animals; Cattle; Chewing Gum; Dentin; Propolis; Tooth Remineralization; Xylitol
PubMed: 32120052
DOI: 10.1016/j.archoralbio.2020.104684 -
Dental Materials : Official Publication... Apr 2013Phosphoric acid-Bioglass 45S5 paste can create an interaction layer formed of calcium-phosphate crystals on the dentin surface. In this study, the efficiency of... (Comparative Study)
Comparative Study
OBJECTIVES
Phosphoric acid-Bioglass 45S5 paste can create an interaction layer formed of calcium-phosphate crystals on the dentin surface. In this study, the efficiency of decreasing the dentin permeability exerted by the interaction layer formed between bioglass and dentin was compared to a resin-containing oxalate desensitizing agent (MS Coat One) and a resin-free oxalate desensitizing agent (Super Seal).
METHODS
Dentin permeability was measured before/after a brushing abrasion challenge, followed by examining the top and the fractured dentin surfaces with a field emission scanning electron microscope. Moreover, the chemical nature of the compounds formed on top of the dentin surface was examined using the field emission scanning electron microscope (FE-SEM) equipped with an energy-dispersive X-ray spectroscope (EDS), and the crystalline structures of the dentinal surfaces were examined by X-ray diffraction (XRD).
RESULTS
The results showed that application of 45S5 bioglass paste to dentin was able to occlude patent dentinal tubule orifices with a layer of calcium-phosphate crystals, while the oxalate containing agents were able to form small crystals which were found in dentinal tubule orifices and scattered along the superficial parts of the dentinal tubule lumen. The brushing-abrasion challenge significantly increased the permeability of dentin treated by Super Seal and MS Coat One, while these challenges had no significant effect on the dentin permeability of specimens treated with 45S5 bioglass paste.
SIGNIFICANCE
The new technique provided better durability than two products available on the market. Moreover, our previous research showed the biocompatibility of using this technique on dental pulp cells, suggesting that this technique can aid in treating dentin hypersensitivity cases.
Topics: Biocompatible Materials; Ceramics; Dentin; Dentin Desensitizing Agents; Dentin Permeability; Dentin Sensitivity; Glass; Humans; Microscopy, Electron, Scanning; Oxalates; Phosphoric Acids; Spectrometry, X-Ray Emission; Statistics, Nonparametric; Surface Properties; X-Ray Diffraction
PubMed: 23347789
DOI: 10.1016/j.dental.2012.12.002