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Microorganisms May 2023Whether a minimum quantity of saliva inhibit the caries process remains uncertain. This study aimed to investigate the impact of saliva dilutions on an in vitro caries...
OBJECTIVE
Whether a minimum quantity of saliva inhibit the caries process remains uncertain. This study aimed to investigate the impact of saliva dilutions on an in vitro caries model using () biofilms.
METHODS
biofilms were cultivated on enamel and root dentin slabs, in culture media containing different proportions of saliva (/): 0%, 5%, 10%, 25%, 50%, 75%, and 100% saliva, and exposed to a 10% sucrose solution (5 min, 3x/day), with appropriate controls. After 5 (enamel) and 4 (dentin) days, demineralization, biomass, viable bacteria, and polysaccharide formation were analyzed. The acidogenicity of the spent media was monitored overtime. Each assay was performed in triplicate across two independent experiments (n = 6).
RESULTS
In both enamel and dentin, an inverse relationship was observed between acidogenicity, demineralization, and the proportion of saliva. Even small quantities of saliva incorporated into the media led to a noticeable reduction in enamel and dentin demineralization. Saliva presence resulted in significant reductions in biomass, viable cells, and polysaccharides, with the effects being concentration-dependent for both tissues.
CONCLUSIONS
High quantities of saliva can almost completely inhibit sucrose-induced cariogenicity, while even small amounts exhibit a dose-dependent caries-protective effect.
PubMed: 37374928
DOI: 10.3390/microorganisms11061426 -
Regenerative Therapy Dec 2022The role of osteopontin (OPN) following severe injury remains to be elucidated, especially its relationship with type I collagen (encoded by the gene) secretion by...
INTRODUCTION
The role of osteopontin (OPN) following severe injury remains to be elucidated, especially its relationship with type I collagen (encoded by the gene) secretion by newly-differentiated odontoblast-like cells (OBLCs). In this study, we examined the role of OPN in the process of reparative dentin formation with a focus on reinnervation and revascularization after tooth replantation in knockout (KO) and wild-type (WT) mice.
METHODS
Maxillary first molars of 2- and 3-week-old- KO and WT mice ( KO 2W, KO 3W, WT 2W, and WT 3W groups) were replanted, followed by fixation 3-56 days after operation. Following micro-computed tomography analysis, the decalcified samples were processed for immunohistochemistry for Ki67, Nestin, PGP 9.5, and CD31 and hybridization for .
RESULTS
An intense inflammatory reaction occurred to disrupt pulpal healing in the replanted teeth of the KO 3W group, whereas dental pulp achieved healing in the KO 2W and WT groups. The tertiary dentin in the KO 3W group was significantly decreased in area compared with the KO 2W and WT groups, with a significantly low percentage of Nestin-positive, newly-differentiated OBLCs during postoperative days 7-14. In the KO 3W group, the blood vessels were significantly decreased in area and pulp healing was disturbed with a failure of pulpal revascularization and reinnervation.
CONCLUSIONS
OPN is necessary for proper reinnervation and revascularization to deposit reparative dentin following severe injury within the dental pulp of erupted teeth with advanced root development.
PubMed: 36313391
DOI: 10.1016/j.reth.2022.09.011 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Mar 2022This work evaluated the effects of thickness on resin bonding strength.
OBJECTIVES
This work evaluated the effects of thickness on resin bonding strength.
METHODS
We set the two bulk-fill composites Filtek Bulk Fill Posterior (FBF) and Tetric N-Ceram Bulk Fill (TBF) as the experimental groups and the two conventional composites Filtek Z100 (Z100) and Spectrum TPH (ST) as the control groups. The translucency parameter (TP), color difference, Vickers hardness (HV), and microtensile bond strength (μTBS) of dentine and the resin composites were measured at different depths.
RESULTS
In each group, TP and HV decreased with the increase in thickness. At the same depth, the TP of the bulk-fill composites was higher than that of the conventional composites. At the same depth, the HV of the four different resin composites followed the order of Z100>FBF>TBF>ST (except for the upper surface). Except for FBF at 3 and 4 mm, all of the other groups showed no visible color change at all the tested thicknesses. Although the μTBS values of the four different composites obtained through the bulk-fill technique were lower than those of composites obtained through the incremental fill technique, the μTBS of the bulk-fill composites obtained through the bulk-filling technique can reach 30 MPa.
CONCLUSIONS
Bulk-fill composites applied in single 4 mm increments can meet the requirements of clinical application. However, the color stability of some bulk-fill composites cannot be maintained.
PubMed: 38597049
DOI: 10.7518/hxkq.2022.02.007 -
International Journal of Nanomedicine 2023To investigate the effects of proanthocyanidins (PA), myricetin, resveratrol, and kaempferol on the modification of dentin collagen and the inhibition of matrix...
OBJECTIVE
To investigate the effects of proanthocyanidins (PA), myricetin, resveratrol, and kaempferol on the modification of dentin collagen and the inhibition of matrix metalloproteinase (MMP) activity, and to evaluate their contributions to the biomimetic remineralization and resin-dentin bonding performance.
METHODS
Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and in situ zymography were applied to verify the collagen modification and MMP activity inhibition induced by these four polyphenols. Scanning electron microscopy/energy dispersive spectrometer (SEM/EDS) analysis, X-ray diffraction (XRD), ATR-FTIR, Vickers hardness numbers (VHN), and micro-computed tomography (micro-CT) were performed to characterize the remineralized dentin. Microtensile bond strength (μTBS) and nanoleakage were investigated to evaluate the effects of the four polyphenols on resin-dentin bonding durability.
RESULTS
ATR-FTIR and in situ zymography confirmed that these four polyphenols could modify dentin collagen and inhibit MMP activity, respectively. Chemoanalytic characterization exhibited the efficacies of the four polyphenols in promoting dentin biomimetic remineralization. The surface hardness of PA-pretreated dentin was the greatest. Micro-CT results demonstrated that the PAs group possessed the highest amount of dentin surface minerals and the lowest amount of deep-layer minerals. The surface and deep-layer mineral contents of the Myr group were higher than Res and Kae groups. Treatment with these four polyphenols significantly increased the initial μTBS compared with the control group without primer conditioning. μTBS decreased significantly during aging, and the decrease was more severe in the PAs and Kae groups than in the Myr and Res groups. With or without aging, the polyphenol groups exhibited relatively less fluorescence. However, the Myr and Res groups showed less serious nanoleakage after aging.
CONCLUSION
PA, myricetin, resveratrol, and kaempferol can modify dentin collagen, inhibit MMP activity, promote biomimetic remineralization, and improve resin-dentin bond durability. Compared with PA and kaempferol, myricetin and resveratrol are more effective in improving resin-dentin bonding.
Topics: Kaempferols; Polyphenols; Resveratrol; X-Ray Microtomography; Dentin; Minerals; Proanthocyanidins; Nanoparticles; Collagen; Tensile Strength; Materials Testing; Dental Bonding; Resin Cements
PubMed: 36998600
DOI: 10.2147/IJN.S395631 -
Dental Materials : Official Publication... Feb 2022To determine the long-term effect on the stability of dentin-resin interfaces after the addition of polylactide (PLA) capsules containing proanthocyanidin (PAC) to...
OBJECTIVES
To determine the long-term effect on the stability of dentin-resin interfaces after the addition of polylactide (PLA) capsules containing proanthocyanidin (PAC) to adhesive resin.
METHODS
Sub-micron (SM) and micron (M) size capsules containing PACs were produced using a combination of emulsification and solvent evaporation techniques and characterized. Human dentin surfaces (n = 8) were etched (35% glycolic acid) and primed (15% enriched Vitis vinifera extract solution - VV), followed by the application of an experimental adhesive containing 0 (control), 1.5 wt% of SM or M PAC-filled PLA capsules light cured for 40 s. A crown was built using commercial composite. After 24 h-immersion (37 °C) in simulated body fluid, specimens were serially sectioned into resin-dentin beams. Microtensile bond strength (TBS), micro-permeability and fracture pattern were assessed immediately and after 1 and 2 years. Data were statistically analyzed using two-way ANOVA and post-hoc test (α = 0.05).
RESULTS
Polydisperse capsules were manufactured with average diameter of 0.36 µm and 1.08 µm for SM and M, respectively. The addition of capsules did not affect TBS (p = 0.889). After 2 years, TBS significantly decreased in SM (p = 0.006), whereas M showed similar initial values (p = 0.291). Overall, less micro-permeability was found in M than the control and SM group (p < 0.001). After 2 years, fractured surfaces from capsule-containing groups failed within the adhesive layer while control fractured at the bottom of the hybrid layer.
SIGNIFICANCE
The addition of PAC-filled PLA microcapsules in a dental adhesive did not affect the bond strength while increased and sustained the protection against micro-permeability in the interface, likely due to release of PACs.
Topics: Composite Resins; Dental Bonding; Dental Cements; Dentin; Dentin-Bonding Agents; Humans; Materials Testing; Microscopy, Electron, Scanning; Proanthocyanidins; Resin Cements; Tensile Strength
PubMed: 34998601
DOI: 10.1016/j.dental.2021.12.024 -
Microorganisms Jun 2021() is a group of viridans mostly located in oral flora among the wide and biodiverse biofilm. It plays a significant role not only in caries formation but also... (Review)
Review
() is a group of viridans mostly located in oral flora among the wide and biodiverse biofilm. It plays a significant role not only in caries formation but also triggering intracerebral haemorrhage. The durable and stable bond interface, besides bacteria elimination, is one of the crucial factors influencing the resin composite restoration performance. This study aimed to evaluate universal adhesives (UAs) with regard to in vitro bond strength to dentin, and the inhibition of the growth and compare them with UAs modified with antimicrobial agents through a systematic review and meta-analysis. Two reviewers performed a literature search up to April 2021 in 5 electronic databases: PubMed MedLine, Scielo, ISI Web of Science, Scopus, and EMBASE. Only in vitro studies reporting the effect of modifying UAs with antimicrobial agents on the bond strength to dentin and/or on the inhibition of the were included. Analyses were carried out using Review Manager Software version 5.3.5 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). The methodological quality of each in vitro study was evaluated following the parameters of a previous systematic review. A total of 1716 potentially relevant publications were recognized. After reviewing the title and abstract, 16 studies remained in the systematic review. From these, a total of 3 studies were included in the meta-analysis. Since data from the studies included in the antimicrobial outcome included zero values, they could not be meta-analysed. Including 0 values in the analysis will lead to several biases in the analysis, so these data were discarded. The antibacterial effect against of UAs modified with antimicrobial agents was higher than the non-modified adhesive systems. Within the limitations of the present study, the bond strength of UAs to dentin could be improved by using antimicrobial agents. The UAs modified with antibacterial agents showed a decrease in the viability of biofilm, among the adhesives tested. However, there are not enough valid data on antibacterial properties of modified UAs; therefore, more well-designed research on these materials is needed.
PubMed: 34204100
DOI: 10.3390/microorganisms9061230 -
Polymers Aug 2021The study aimed at synthesizing β-tricalcium phosphate (β-TCP) nanoparticles and comparing the mechanical properties and dentin interaction of two adhesives:...
The study aimed at synthesizing β-tricalcium phosphate (β-TCP) nanoparticles and comparing the mechanical properties and dentin interaction of two adhesives: experimental adhesive (EA) and EA with 5 wt.% β-TCP nanoparticles (β-TCP-5%). These filler nanoparticles were synthesized and then characterized with scanning electron microscopy (SEM) and micro-Raman spectroscopy. The β-TCP nanoparticles were incorporated in the adhesives to form two groups: gp-1: EA (control) and gp-2: β-TCP-5%. These adhesives were characterized by SEM, energy-dispersive X-ray (EDX) spectroscopy and were also assessed for their micro-tensile bond strength (μTBS) with (TC) and without thermocycling (NTC). Fourier Transform Infrared (FTIR) spectroscopy was performed to evaluate the degree of conversion (DC) of two adhesives. The β-TCP filler was seen as irregularly shaped agglomerates on SEM. The micro-Raman spectra revealed characteristic peaks associated with β-TCP nanoparticles. Both adhesives presented suitable dentin interaction, which was demonstrated by the formation of resin tags of variable depths. The EDX analysis verified the existence of calcium (Ca) and phosphate (P) for the β-TCP-5% group. The greatest μTBS values were shown by β-TCP-5% group samples when they were non-thermocycled (NTC) (β-TCP-5%-NTC: 34.11 ± 3.46) followed by the thermocycled (TC) samples of the same group (β-TCP-5%-TC: 30.38 ± 3.66), compared with the EA group. Although the DC presented by β-TCP-5% group was comparable to the EA group, it was still lower. The addition of β-TCP nanoparticles in the adhesive improved its μTBS and resulted in a suitable dentin interaction, seen in the form of hybrid layer and resin tag formation. Nonetheless, a decreased DC was observed for the β-TCP-5% adhesive. Future studies probing the effect of different filler concentrations on various properties of the adhesive are warranted.
PubMed: 34502894
DOI: 10.3390/polym13172855 -
Journal of Conservative Dentistry : JCD 2021Lack of bond stability between the composite resin and dentin remains one of the main reasons for having to replace esthetic restorations.
BACKGROUND
Lack of bond stability between the composite resin and dentin remains one of the main reasons for having to replace esthetic restorations.
AIM
This study aimed to evaluate the influence of chlorhexidine (CHX) on the bond strength of a total etching system to dentin tissue after degradation of the adhesive interface.
MATERIALS AND METHODS
One hundred and eighty fragments of human molars were divided into three groups ( = 15) according to the materials used during the acid-etching step: Group 1 (control), 37% phosphoric acid; Group 2, a combined solution of 37% phosphoric acid and 2% CHX; and Group 3, 37% phosphoric acid followed by 2% CHX. Following the restorative procedures, the groups were divided into four subgroups according to the number of thermal cycles (TC) and to the time of storage in water (SW), and then subjected to a shear strength test, until fracture: (A) 0 TC/24-h SW; (B) 500 TC/1-week SW; (C) 2,000 TC/1-month SW; and (D) 12,000 TC/6-month SW. Two-way analysis of variance and Duncan's complementary test were used to perform multiple comparisons.
RESULTS
After the 24-h and 1-week SW time periods, no statistically significant difference was found among the shear strength values of the control and the experimental groups: 5.48 ± 0.59 MPa, 5.44 ± 0.56 MPa, and 5.65 ± 0.94 MPa for G1, G2, and G3, respectively. However, the shear strength values decreased significantly in all the study groups after 1 month, namely 3.60 ± 0.41 MPa, 3.08 ± 0.65 MPa, and 3.49 ± 0.23 MPa for G1, G2, and G3, respectively. After 6 months, similar results were found for G1 and G3, namely 2.77 ± 0.58 MPa and 1.74 ± 0.52 MPa, respectively, whereas the 0.77 ± 0.26 MPa value found for G2 was significantly lower than those found for the G1 and G3 groups. No differences were found between the groups with respect to fracture-type frequencies.
CONCLUSION
The use of CHX as an agent to rehydrate the dentin had a negative influence on bond strength.
PubMed: 35282582
DOI: 10.4103/jcd.jcd_223_21 -
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 -
The Journal of Histochemistry and... Oct 2020Dentin sialophosphoprotein (DSPP), which expresses and synthesizes in odontoblasts of dental pulp, is a critical protein for normal teeth mineralization. Originally,...
Dentin sialophosphoprotein (DSPP), which expresses and synthesizes in odontoblasts of dental pulp, is a critical protein for normal teeth mineralization. Originally, DSPP was identified as a dentin-specific protein. In 2010, DSPP was also found in femoral head cartilage, and it is still unclear what roles DSPP play in femoral head cartilage formation, growth, and maintenance. To reveal biological functions of DSPP in the femoral head cartilage, we examined null mice compared with wild-type (WT) mice to observe DSPP expression as well as localization in WT mice and to uncover differences of femoral head cartilage, bone morphology, and structure between these two kinds of mice. Expression data demonstrated that DSPP had heterogeneous fragments, expressed in each layer of femoral head cartilage and subchondral bone of WT mice. null mice exhibited a significant reduction in the thickness of femoral head cartilage, with decreases in the amount of proliferating cartilage cells and increases in apoptotic cells. In addition, the subchondral bone mineralization decreased, and the expressions of vessel markers (vascular endothelial growth factor [VEGF] and CD31), osteoblast markers (Osterix and dentin matrix protein 1 [DMP1]), osteocyte marker (sclerostin [SOST]), and osteoclast marker (tartrate-resistant acid phosphatase [TRAP]) were remarkably altered. These indicate that DSPP deletion can affect the proliferation of cartilage cells in the femoral head cartilage and endochondral ossification in subchondral bone. Our data clearly demonstrate that DSPP plays essential roles in the femoral head cartilage growth and maintenance and subchondral biomineralization.
Topics: Animals; Calcification, Physiologic; Cartilage; Cell Proliferation; Extracellular Matrix Proteins; Femur Head; Mice; Mice, Knockout; Phosphoproteins; Sialoglycoproteins
PubMed: 32921220
DOI: 10.1369/0022155420960403