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Journal of Functional Biomaterials Jan 2024The aim of this study is to investigate dentin chemical and ultrastructural changes upon exposure to remineralizing dentifrices. Dentin disks were obtained from...
The aim of this study is to investigate dentin chemical and ultrastructural changes upon exposure to remineralizing dentifrices. Dentin disks were obtained from permanent human molars and treated for 7 days with the dentifrices: (1) C group-control (no dentifrice); (2) S group-Sensodyne Repair & Protect; (3) D group-Dentalclean Daily Regenerating Gel; and (4) DB group-D group + Dentalclean regenerating booster. Afterwards, samples were submitted to an additional 7 days of toothbrushing associated with daily acidic challenge. Samples were imaged and analyzed (days 1, 7, and 14) for Young's modulus by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). SEM and AFM revealed precipitate deposition on dentin surfaces in groups S, D, and DB, formed as early as day 1. Surface elemental analysis showed a Si increase on all brushed surfaces. Similar surface morphology was maintained after the acidic challenge period. Bright-field TEM/SAED revealed the formation of nanocrystalline hydroxyapatite inside the dentin tubules of groups S, D, and DB after day 7. Group C presented a gradual reduction of Young's modulus from days-1-14, whereas all remaining groups had increased values. All evaluated dentifrices led to successful formation of hydroxyapatite and increased dentin stiffness.
PubMed: 38248692
DOI: 10.3390/jfb15010025 -
Journal of Translational Medicine Jan 2024Revascularization and restoration of normal pulp-dentin complex are important for tissue-engineered pulp regeneration. Recently, a unique periodontal tip-like...
BACKGROUND
Revascularization and restoration of normal pulp-dentin complex are important for tissue-engineered pulp regeneration. Recently, a unique periodontal tip-like endothelial cells subtype (POTCs) specialized to dentinogenesis was identified. We have confirmed that TPPU, a soluble epoxide hydrolase (sEH) inhibitor targeting epoxyeicosatrienoic acids (EETs) metabolism, promotes bone growth and regeneration by angiogenesis and osteogenesis coupling. We hypothesized that TPPU could also promote revascularization and induce POTCs to contribute to pulp-dentin complex regeneration. Here, we in vitro and in vivo characterized the potential effect of TPPU on the coupling of angiogenesis and odontogenesis and investigated the relevant mechanism, providing new ideas for pulp-dentin regeneration by targeting sEH.
METHODS
In vitro effects of TPPU on the proliferation, migration, and angiogenesis of dental pulp stem cells (DPSCs), human umbilical vein endothelial cells (HUVECs) and cocultured DPSCs and HUVECs were detected using cell counting kit 8 (CCK8) assay, wound healing, transwell, tube formation and RT-qPCR. In vivo, Matrigel plug assay was performed to outline the roles of TPPU in revascularization and survival of grafts. Then we characterized the VEGFR2 + POTCs around odontoblast layer in the molar of pups from C57BL/6 female mice gavaged with TPPU. Finally, the root segments with DPSCs mixed with Matrigel were implanted subcutaneously in BALB/c nude mice treated with TPPU and the root grafts were isolated for histological staining.
RESULTS
In vitro, TPPU significantly promoted the migration and tube formation capability of cocultured DPSCs and HUVECs. ALP and ARS staining and RT-qPCR showed that TPPU promoted the osteogenic and odontogenic differentiation of cultured cells, treatment with an anti-TGF-β blocking antibody abrogated this effect. Knockdown of HIF-1α in HUVECs significantly reversed the effect of TPPU on the expression of angiogenesis, osteogenesis and odontogenesis-related genes in cocultured cells. Matrigel plug assay showed that TPPU increased VEGF/VEGFR2-expressed cells in transplanted grafts. TPPU contributed to angiogenic-odontogenic coupling featured by increased VEGFR2 + POTCs and odontoblast maturation during early dentinogenesis in molar of newborn pups from C57BL/6 female mice gavaged with TPPU. TPPU induced more dental pulp-like tissue with more vessels and collagen fibers in transplanted root segment.
CONCLUSIONS
TPPU promotes revascularization of dental pulp regeneration by enhancing migration and angiogenesis of HUVECs, and improves odontogenic differentiation of DPSCs by TGF-β. TPPU boosts the angiogenic-odontogenic coupling by enhancing VEGFR2 + POTCs meditated odontoblast maturation partly via upregulating HIF-1α, which contributes to increasing pulp-dentin complex for tissue-engineered pulp regeneration.
Topics: Mice; Animals; Female; Humans; Dental Pulp; Epoxide Hydrolases; Mice, Nude; Stem Cells; Mice, Inbred C57BL; Regeneration; Cells, Cultured; Human Umbilical Vein Endothelial Cells; Cell Differentiation; Dentin
PubMed: 38229161
DOI: 10.1186/s12967-024-04863-y -
International Dental Journal May 2024This study aimed to evaluate the relative dentin abrasivity of whitening toothpastes containing acids using the Radioactive Dentin Abrasivity - Profilometry Equivalent...
INTRODUCTION AND AIMS
This study aimed to evaluate the relative dentin abrasivity of whitening toothpastes containing acids using the Radioactive Dentin Abrasivity - Profilometry Equivalent (RDA-PE).
METHODS
A total of 100 bovine dentin specimens were prepared and assigned to the following groups (n = 10): 5 hydrogen peroxide (HP) whitening toothpastes (WTH1-WTH5) with or without acid (citric acid, ethylenedinitrilotetraacetic acid disodium, and phosphoric acid), 2 whitening toothpastes with silica and containing citric or phosphoric acid (WTS1 and WTS2), one conventional toothpaste (CT), and 2 reference slurries (RS). All specimens were brushed for 4,000 or 10,000 strokes using toothbrush and toothbrushing machine. The average dentin depth was measured using a noncontact profilometery, and the RDA-PE value was calculated based on the RS. The pH of the solution, average particle size, particle content, and particle hardness were measured. The RDA-PE data were analysed using one-way analysis of variance and Tukey's test, and the effects of the 4 measured factors on RDA-PE were investigated via multiple regression analysis.
RESULTS
The RDA-PE values of the HP whitening toothpastes (mean value: 19-46) were significantly lower, whereas those of the silica whitening toothpastes (80 or 111) were similar to those of the RS after 4,000 strokes (100). The RDA-PE values of all whitening toothpastes were significantly lower than the RS values after 10,000 strokes (242). The HP whitening toothpastes were slightly acidic (pH ≤6) compared to the other solutions. The HP (2.9%-3.7%) and silica (8.9% or 9.9%) whitening toothpastes had significantly lower particle content than RS (16.6%). The particle content significantly influenced the RDA-PE values by multiple regression results.
CONCLUSIONS
The RDA-PE values of whitening toothpastes varied. The particle content in the solution was a key factor affecting the RDA-PE value.
CLINICAL RELEVANCE
Whitening toothpastes containing acids did not cause significant dentin abrasion.
PubMed: 38762371
DOI: 10.1016/j.identj.2024.04.004 -
BMC Oral Health Sep 2023Hydrogen peroxide (HP) and citric acid (CA), key contributors to toothpaste acidity, can lead to dental loss. This study aimed to compare the amount of abrasion or loss...
BACKGROUND
Hydrogen peroxide (HP) and citric acid (CA), key contributors to toothpaste acidity, can lead to dental loss. This study aimed to compare the amount of abrasion or loss of dentin based on pH, buffering, and concentration of HP and CA in commercial and experimental toothpastes after toothbrushing or immersion.
METHODS
Bovine dentin specimens were randomly assigned to nine solutions. The prepared solutions included two commercial toothpastes (whitening toothpaste [WT] with HP and CA; conventional toothpaste [CT] without HP and CA), reference slurry (RS), two CA solutions (1.92%, CAS1; 0.001%, CAS2), basic solution (7.16% sodium phosphate dibasic [SPDS]), CA phosphate buffer solution (3.58% SPDS and 0.96% CA [CAPB]), HP solution (4%, HPS), and distilled water (DW). Dentin specimens were performed in two treatments: one with only abrasion (10,000 brushings) and one with only immersion (1 h). After treatments, the amount of dentin loss and surface images were measured and observed using noncontact profilometry. Data were analyzed using an one-way analysis of variance and the Tukey test as a post hoc analysis (p < 0.05).
RESULTS
WT with pH 5.0 had lower dentin abrasion than CT and RS after brushing but had higher dentin loss than both after immersion. The dentin surfaces of CAS1, CAPB, and WT were damaged after immersion, whereas HPS, CAS2, CT, SPDS, RS, and DW remained intact after soaking. CAS2 and HPS, which had a pH of 5.0 like WT, did not significantly differ from those of DW after brushing.
CONCLUSIONS
WT containing HP and CA did not cause significant dentin abrasion but may cause additional dentin loss even without brushing. After brushing or immersion, the CA concentration may affect the dentin surface more than the HP concentration included in WT. The amount of abrasion or loss of dentin after brushing or soaking can vary based on the composition, concentration, and buffer in the solution, even if the pH of the solution is similar to pH 5.0.
Topics: Humans; Animals; Cattle; Hydrogen Peroxide; Toothpastes; Citric Acid; Dentin
PubMed: 37658357
DOI: 10.1186/s12903-023-03319-x -
Journal of Dental Sciences Jul 2023Naturally derived collagen crosslinkers with matrix metalloproteinases (MMPs) inhibitory activity for dentin bonding have been previously studied. One of these...
BACKGROUND/PURPOSE
Naturally derived collagen crosslinkers with matrix metalloproteinases (MMPs) inhibitory activity for dentin bonding have been previously studied. One of these crosslinkers is flavonoids. The purpose of this study was to investigate whether dentin pretreatment with kaempferol (KEM), one of the flavonoids, enhances dentin bond stability and nanoleakage at the dentin-resin interface through MMPs inhibition and collagen crosslinking.
MATERIALS AND METHODS
The experimental KEM-containing solution was used to pretreat demineralized dentin prior to the application of a universal adhesive. KEM is a natural flavonoid and those which did not take the experimental solution served as the control group (CON). Microtensile bond strength (μTBS) and nanoleakage tests were conducted before and after the thermocycling to evaluate the influence of KEM on dentin bond strength. The MMPs inhibition activity of KEM was analyzed via MMPs zymography using a confocal microscopy. Fourier-transform infrared (FTIR) spectroscopy was used to demonstrate that KEM inhibits MMPs and enhances collagen crosslinking.
RESULTS
The μTBS values of KEM group exhibited a higher bond strength after thermocycling. At the resin-dentin interface, the KEM group did not exhibit any signs of nanoleakage after thermocycling. Furthermore, MMPs zymography confirmed that there was a relatively low activity of MMPs in the presence of KEM. In FTIR analysis, the PO peak representing the cross-link between dentin and collagen was significantly higher in the KEM group.
CONCLUSION
Our findings suggest that pretreatment with KEM enhances the dentin bonding stability at the resin-dentin interface by acting as a collagen crosslinker and MMPs inhibitor.
PubMed: 37404650
DOI: 10.1016/j.jds.2022.12.002 -
Dentistry Journal Sep 2023Until recently, it was widely accepted that bacteria participate in caries pathogenesis mainly through carbohydrate fermentation and acid production, which promote the... (Review)
Review
Until recently, it was widely accepted that bacteria participate in caries pathogenesis mainly through carbohydrate fermentation and acid production, which promote the dissolution of tooth components. Neutrophils, on the other hand, were considered white blood cells with no role in caries pathogenesis. Nevertheless, current literature suggests that both bacteria and neutrophils, among other factors, possess direct degradative activity towards both dentinal collagen type-1 and/or methacrylate resin-based restoratives and adhesives, the most common dental restoratives. Neutrophils are abundant leukocytes in the gingival sulcus, where they can readily reach adjacent tooth roots or gingival and cervical restorations and execute their degradative activity. In this review, we present the latest literature evidence for bacterial, dentinal, salivary, and neutrophil degradative action that may induce primary caries, secondary caries, and restoration failure.
PubMed: 37754337
DOI: 10.3390/dj11090217 -
Cureus Oct 2023Introduction Non-carious cervical lesions (NCCLs) are structural deformities or tissue loss in the cervical region of teeth, which are closer to the gum line that do...
Introduction Non-carious cervical lesions (NCCLs) are structural deformities or tissue loss in the cervical region of teeth, which are closer to the gum line that do not result from caries (tooth decay). On the tooth enamel at the gingival margin, these lesions are frequently seen as V- or U-shaped notches. The causes of NCCLs are multifaceted and involve intricate relationships between chemical, mechanical, and biological elements. The slow loss of enamel and dentin in the cervical area occurs due to mechanical causes like abrasive toothbrushing and occlusal tension, as well as chemical variables such as erosive acidic food components. As NCCLs advance, dental discomfort, aesthetic issues, and impaired tooth function may result. The aim of this study was to assess the nanoscale configuration of dentin in non-carious cervical lesions using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Methodology Sterilized teeth samples were selected from the extracted tooth repository of Saveetha Dental College and Hospitals, Chennai. Tooth samples were thinly sliced using a diamond bur. The sliced teeth were examined using a scanning electron microscope. Ionic configuration was assessed using EDS and elemental analysis. Results The findings showed the nanoscale morphology and elemental configurations present. Elemental mapping showed specific elemental localization in the affected area. Conclusion NCCLs can be attributed as a predominant factor leading to gingival recession causing dentin exposure and hypersensitivity. NCCLs can also threaten the integrity of dentin; therefore, early diagnosis of non-carious cervical lesions is crucial to ensure proper treatment plan and therapeutic regimens.
PubMed: 38034251
DOI: 10.7759/cureus.48003 -
European Journal of Dentistry Jul 2023The aim of this study was to comparatively evaluate microshear bond strength (μSBS) of bioactive ionic resin composite and resin-modified glass ionomer liner (RMGI)...
OBJECTIVES
The aim of this study was to comparatively evaluate microshear bond strength (μSBS) of bioactive ionic resin composite and resin-modified glass ionomer liner (RMGI) to dentin and resin composite.
MATERIALS AND METHODS
The enamel of 11 posterior molar teeth was removed to expose dentin and then placed in acrylic blocks. Each specimen received three microcylindrical Tygon tubes filled with bioactive ionic resin composite (Activa Bioactive base/liner (PULPDENT: , MA, USA)), RMGI (Riva light cure SDI LTD, Bayswater, Australia), and resin composite (Filtek Z350xt, MN, USA). Composite discs ( = 11) were fabricated from nanofilled resin composite (Filtek Z350xt) and then fixed in acrylic blocks. Each specimen received two microcylindrical Tygon tubes filled with Activa Bioactive base/liner and Riva RMGI. All specimens were mounted individually to universal testing machine for μSBS test. Failure modes were analyzed using stereomicroscope and scanning electron microscope.
RESULTS
Filtek Z350xt nanofilled resin composite showed the highest μSBS values. No statistical significant difference was found between Activa Bioactive and Riva RMGI ( > 0.05).
CONCLUSION
Bioactive ionic resin composite liner exhibited similar bond strength as RMGI to dentin and resin composite.
PubMed: 36307111
DOI: 10.1055/s-0042-1756692 -
Frontiers in Bioengineering and... 2023This paper aimed to assess the impact of the acetone wet-bonding (AWB) technique on dentin bonding and to investigate its potential underlying mechanisms. Caries-free...
This paper aimed to assess the impact of the acetone wet-bonding (AWB) technique on dentin bonding and to investigate its potential underlying mechanisms. Caries-free third molars were sliced, ground, etched, water-rinsed. Then the specimens were randomly allocated to four groups according to the following pretreatments: 1. water wet-bonding (WWB); 2. ethanol wet-bonding (EWB); 3. 50% (v/v) acetone aqueous solution (50%AWB); 4. 100% acetone solution (AWB). Singlebond universal adhesive was then applied and composite buildups were constructed. The microtensile bond strength (MTBS), failure modes and interface nanoleakage were respectively evaluated after 24 h of water storage, 10,000 times of thermocycling or 1-month collagenase ageing. zymography and contact angle were also investigated. Acetone pretreatment preserved MTBS after thermocycling or collagenase ageing ( 0.05) without affecting the immediate MTBS ( 0.05). Furthermore, AWB group manifested fewer nanoleakage than WWB group. More importantly, the contact angle of the dentin surfaces decreased significantly and collagenolytic activities within the hybrid layer were suppressed in AWB group. This study suggested that the AWB technique was effective in enhancing the dentin bond durability by increasing the wettability of dentin surface to dental adhesives, removing residual water in the hybrid layer, improving the penetration of adhesive monomer, and inhibiting the collagenolytic activities. The lifespan of adhesive restorations would be increased by utilization of acetone wet-bonding technique.
PubMed: 38169916
DOI: 10.3389/fbioe.2023.1309503 -
Journal of Conservative Dentistry and... 2023To determine the effect of three different dentin hypersensitivity treatment procedures on the microtensile bond strength of etch and rinse and self-etch adhesive system.
AIM
To determine the effect of three different dentin hypersensitivity treatment procedures on the microtensile bond strength of etch and rinse and self-etch adhesive system.
MATERIALS AND METHODS
Eighty extracted intact human permanent lower premolars were decoronated, and dentin was exposed on the buccal surface. The teeth were randomly assigned to two experimental groups of 40 teeth each: etch and rinse system or self-etch system. The 40 samples assigned were further randomly assigned to four desensitizing treatment subgroups: Control, Gluma, NovaMin, and GC tooth Mousse with 10 samples per subgroup. Desensitizing treatment was performed two times each day for 2 weeks respectively. The exposed dentin was subjected to etch and rinse or self-etch adhesive system bonding agent as per the group and restored using composite to 4-mm thickness. Samples were then subjected to universal testing machine for microtensile bond strength.
RESULTS
The bond strength to the dentin obtained with etch and rinse adhesive system group where significantly higher ( < 0.05) when compared to self-etch adhesive system. However, there was no significant effect of the desensitizing agent on the microtensile bond strength in its own. Scanning electron microscope imaging reviled tubular occlusion in all specimens treated with desensitizer.
CONCLUSION
The bond strength was majorly impacted by the type of adhesive system used. While the desensitizing agents used in the study had little or no adverse effect on the bond strength of composites to dentin surface.
PubMed: 38292373
DOI: 10.4103/JCDE.JCDE_36_23