-
Polymers Apr 2024This study evaluated the effect of simulated pulpal pressure (SPP) conditions and storage time on contemporary adhesive systems' microtensile bond strength (µTBS) to...
This study evaluated the effect of simulated pulpal pressure (SPP) conditions and storage time on contemporary adhesive systems' microtensile bond strength (µTBS) to dentin. Extracted human molars were prepared and randomly divided into four groups according to the adhesives: Clearfil Megabond 2 (CSE), Beautibond Xtreme Universal (BXU), G2-Bond (G2B), and Scotchbond Universal Plus (SBP). Each adhesive group was further divided following the SPP conditions: control with no simulation (SPP-CTR), SPP with distilled water (SPP-DTW), and SPP with fetal bovine serum (SPP-FBS). Resin composite build-ups were prepared, and teeth were stored in water (37 °C) for 24 h (24 h) and 3 months (3 m). Then, teeth were sectioned to obtain resin-dentin bonded beams and tested to determine the µTBS. Data were analyzed using three-way ANOVA, Tukey post hoc tests (=0.05), and Weibull failure analysis. Failure mode was observed using scanning electron microscopy. The µTBS response was affected by adhesive systems, simulated pulpal pressure conditions, and storage time. SPP-CTR groups presented a higher overall bond strength than SPP-DTW and SPP-FBS, which were not significantly different from each other. Only for SBP, the SPP-FBS group showed higher µTBS than the SPP-DTW group. The Weibull analysis showed that the bonding reliability and durability under SPP-DTW and SPP-FBS were inferior to SPP-CTR, and the 24 h bonding quality of adhesives to dentin was superior to that of 3 m. SPP drastically reduced the µTBS of all adhesives to dentin regardless of solution (distilled water or fetal bovine serum). Storage after 3 m also decreased µTBS despite the SPP condition.
PubMed: 38732688
DOI: 10.3390/polym16091219 -
Dental Materials : Official Publication... Jun 2024Acrylamides were shown to significantly improve bonding stability in adhesive restorations, but the reinforcement mechanism has not been fully elucidated. We tested the...
OBJECTIVES
Acrylamides were shown to significantly improve bonding stability in adhesive restorations, but the reinforcement mechanism has not been fully elucidated. We tested the hypothesis that hydrogen bonding reinforcement of the collagen network (with secondary or tertiary acrylamides), as well as degree of crosslinking of the polymer network (with di- or tri-functional acrylamides), can be two of the factors at play.
METHODS
Two-step total etch adhesives comprising UDMA (60 wt%) and 40 wt% of: TAAEA, TMAAEA (secondary, tertiary tri-acrylamides), BAAP, DEBAAP (secondary, tertiary di-acrylamides) or HEMA (mono-methacrylate - control) were formulated. Simulated composite restorations (n = 5) were tested after cyclic mechanical and biological (S. mutans biofilm) challenges. Gap formation before and after aging was assessed with SEM imaging. Micro-tensile bond strength (μTBS, n = 6) was assessed after seven-day incubation in water or S. mutans-containing culture medium. Collagen reinforcement was assessed with hydroxyproline assay (n = 10) and rheology (n = 3). Data were analyzed with one-way/two-way ANOVA/Tukey's test (alpha=5%).
RESULTS
Gap formation increased and bond strength decreased for all monomers after biofilm incubation (p < 0.001). Except for DEBAAP, secondary and tertiary di/tri-acrylamides showed lower occlusal gap width values, but no significant differences overall gap length compared to HEMA. μTBS increased for tri-acrylamides compared with HEMA. Samples treated with multi-acrylamides had lower concentration of hydroxyproline (by-product of collagen degradation) (p < 0.001), except for DEBAAP, which showed values close to HEMA (p > 0.05). Dentin shear modulus increased for all acrylamides after 72 h, especially TMAAEA.
SIGNIFICANCE
In general, multi-acrylamides promote collagen reinforcement, leading to reduced gap formation, and stabilize the bond strength under physiological conditions.
Topics: Collagen; Tensile Strength; Materials Testing; Dental Bonding; Acrylamides; Methacrylates; Composite Resins; Rheology; Microscopy, Electron, Scanning; Hydrogen Bonding; Surface Properties; Dental Stress Analysis; Resin Cements; Polyurethanes
PubMed: 38729779
DOI: 10.1016/j.dental.2024.05.002 -
Journal of Clinical and Experimental... Apr 2024The aim of the current study was to evaluate the influence of diabetes mellitus and the mode of applying a universal adhesive on the shear bond strength of composite...
BACKGROUND
The aim of the current study was to evaluate the influence of diabetes mellitus and the mode of applying a universal adhesive on the shear bond strength of composite resin to dentin.
MATERIAL AND METHODS
Forty teeth were extracted from diabetic individuals who had been living with diabetes for a period of 5 to 15 years. These forty teeth were divided into two groups: twenty molars from patients with type 1 diabetes and twenty molars from patients with type 2 diabetes. The remaining twenty sound human molars were collected from non-diabetic patients. The collected teeth were assigned into 3 groups, and each group was further divided into 2 subgroups. Group A (n = 20): non-diabetic (ND) where sub group IA: Universal adhesive applied in the total-etch mode (n = 10) and sub group IIA: Universal adhesive applied in the self-etch mode (n = 10). Group B (n = 20): diabetic type 1 (D1) where sub group IB: Universal adhesive applied in the total-etch mode (n = 10) and sub group IIB: Universal adhesive applied in the self-etch mode (n = 10). Group C (n = 20): diabetic type 2 (D2). Where Sub group IC: Universal adhesive applied in the total-etch mode (n = 10) and sub group IIC: Universal adhesive applied in the self-etch mode (n = 10). A Teflon mold measuring 3mm in diameter was attached to the dentin surface, used to build Filtek Z550 to a height of 3mm. The specimens were fixed to the universal testing to measure shear bond strength.
RESULTS
There was a statistically significant difference of Mean ±SD of shear bond strength among the three tested groups. In group A, the Mean ±SD were (21.710 ± 0.638), it was decreased in group B to (14.626 ± 0.726) and group C to (17.740 ± 0.668). Subgroup I had lower shear bond strength values than subgroup II in all tested groups. The difference between each subgroup in groups A, B, and C was significant.
CONCLUSIONS
1. Diabetes mellitus has an adverse effect on the shear bond strength of composite to dentine. 2. Type 1 diabetes mellitus significantly reduces the shear bond strength of composite resin to dentin. 3. Shear bond strength of the universal adhesive was higher when applied to dentin using the self-etch mode, as compared to the total etch mode, in all groups, regardless of whether the participants had diabetes or not. Diabetes Mellitus, Universal Adhesive, Application Mode, Shear bond Strength, Dentine, Composite.
PubMed: 38725826
DOI: 10.4317/jced.61328 -
Journal of Cellular Biochemistry May 2024Odontoblast differentiation is a key process in dentin formation. Mouse dental papilla cells (mDPCs) are pivotal in dentinogenesis through their differentiation into...
Odontoblast differentiation is a key process in dentin formation. Mouse dental papilla cells (mDPCs) are pivotal in dentinogenesis through their differentiation into odontoblasts. Odontoblast differentiation is intricately controlled by transcription factors (TFs) in a spatiotemporal manner. Previous research explored the role of RUNX2 and KLF4 in odontoblast lineage commitment, respectively. Building on bioinformatics analysis of our previous ATAC-seq profiling, we hypothesized that KLF4 potentially collaborates with RUNX2 to exert its biological role. To investigate the synergistic effect of multiple TFs in odontoblastic differentiation, we first examined the spatiotemporal expression patterns of RUNX2 and KLF4 in dental papilla at the bell stage using immunostaining techniques. Notably, RUNX2 and KLF4 demonstrated colocalization in preodontoblast. Further, immunoprecipitation and proximity ligation assays verified the interaction between RUNX2 and KLF4 in vitro. Specifically, the C-terminus of RUNX2 was identified as the interacting domain with KLF4. Functional implications of this interaction were investigated using small hairpin RNA-mediated knockdown of Runx2, Klf4, or both. Western blot analysis revealed a marked decrease in DSPP expression, an odontoblast differentiation marker, particularly in the double knockdown condition. Additionally, alizarin red S staining indicated significantly reduced mineralized nodule formation in this group. Collectively, our findings highlight the synergistic interaction between RUNX2 and KLF4 in promoting odontoblast differentiation from mDPCs. This study contributes to a more comprehensive understanding of the regulatory network of TFs governing odontoblast differentiation.
PubMed: 38720665
DOI: 10.1002/jcb.30577 -
Current Stem Cell Research & Therapy May 2024Complications arising from diabetes can result in stem cell dysfunction, impairing their ability to undergo differentiation into various cellular lineages. The present...
OBJECTIVE
Complications arising from diabetes can result in stem cell dysfunction, impairing their ability to undergo differentiation into various cellular lineages. The present study evaluated the effect of histone deacetylase inhibitors, Valproic acid and Trichostatin A, on the odontogenic differentiation potential of dental pulp stem cells under hyperglycemic conditions.
METHODS
Streptozotocin (STZ) induced diabetes mellitus in 12 male Wistar rats. Dental parameters were examined using micro-computed tomography. The odontogenic potential of human pulp stem cells exposed to 30 mM glucose was assessed through alkaline phosphatase assays, examination of gene expression for dentin matrix protein 1 and dentin sialoprotein using real-time PCR, and alizarin red staining for calcium deposition.
RESULTS
Along with reduced dentin thickness and root length in diabetic rats, the results revealed a significant increase in histone deacetylase 3 and 2 gene expressions in isolated diabetic pulp tissues compared to the control groups. The gene expression of odontogenic-related markers and alkaline phosphatase activity in human cultured pulp stem cells under hyperglycemic conditions significantly decreased. Adding Valproic acid and Trichostatin A restored the odontogenic differentiation markers, including calcium deposition, gene expression of dentin sialophosphoprotein, dentin matrix protein 1, and alkaline phosphatase activity.
CONCLUSION
The data suggests that hyperglycemic conditions negatively impact the odontogenic potential of pulp mesenchymal stem cells. However, histone deacetylase inhibitors improve the impaired odontogenic differentiation capacity. This study implies that histone deacetylases may represent a potential therapeutic target for enhancing the regenerative mineralization of pulp cells in diabetic patients.
PubMed: 38712370
DOI: 10.2174/011574888X309466240429051314 -
Journal of Endodontics May 2024This study aimed to assess BioRoot RCS (BR) incorporating liposomal chlorhexidine digluconate (CHX) for its antibacterial activity, drug release capacity, and...
INTRODUCTION
This study aimed to assess BioRoot RCS (BR) incorporating liposomal chlorhexidine digluconate (CHX) for its antibacterial activity, drug release capacity, and physicochemical properties.
METHODS
Drug release of CHX liposomal formulations in combination with BR was evaluated spectrophotometrically and through mathematical release models for 30 days. A selected combination was evaluated for antimicrobial properties against Enterococcus faecalis biofilm growth on human dentin. Cytotoxicity was assessed following the ISO 10993-5:2019 standard on days 1, 3, and 7. Physicochemical properties were evaluated through setting time, Fourier transform infrared spectroscopy, solubility, contact angle, and film thickness.
RESULTS
From BR, liposomal CHX released up to 7-fold higher CHX than CHX solution (P < .05), following a triphasic drug release pattern compared to the CHX solution, which followed a quasi-Fickian diffusion. BR combined with a selected liposomal CHX completely inhibited E. faecalis biofilm growth compared to the combination of BR with CHX solution and the control group (P < .05). Liposomal CHX decreased the contact angle (P < .05) and solubility but increased cytotoxicity (P < .05) of BR, staying above the ISO threshold. None of the other physicochemical characteristics tested differed from BR (P > .05).
CONCLUSION
This liposomal formulation improved CHX release from BR, enhancing the antibacterial effectiveness. It presents a promising approach for local antibiofilm therapy in endodontics without substantially altering the physicochemical characteristics of BR.
PubMed: 38710385
DOI: 10.1016/j.joen.2024.04.012 -
Frontiers in Oral Health 2024Silver Diammine Fluoride (SDF) is a clinical minimal intervention to manage dentin caries. Its chemistry in demineralization conditions has been investigated widely, but...
INTRODUCTION
Silver Diammine Fluoride (SDF) is a clinical minimal intervention to manage dentin caries. Its chemistry in demineralization conditions has been investigated widely, but far less in remineralization conditions. The aim was to investigate and compare the chemical reactions when SDF is added to remineralization and demineralization solutions.
METHODS
0.01 ml SDF (Riva Star) was added to deionized water (DW); demineralization (DS = pH4) and remineralization (RS = pH7.0) solutions. The time sequence of concentrations of NH, F, and Ag were measured using ion selective electrodes (ISEs) every 2 min. The pH was also measured. Precipitates were characterized using x-ray Diffraction (XRD) and, P and F nuclear magnetic resonance spectroscopy (NMR).
RESULTS
The concentrations of NH and Ag showed decreasing trends in DW (-0.12 and -0.08 mM/h respectively), and in DS (-1.06 and -0.5 mM/h respectively); with corresponding increase in F concentration (0.04 and 0.7 mM/h respectively). However, in RS, NH concentration showed little change (0.001 mM/h), and Ag and F concentrations were negligible. XRD results showed that precipitates (in RS only) contained AgCl, and metallic Ag. NMR showed that fluorapatite/carbonated fluorapatite (FAP/CFAP) were formed. The pH increased after SDF addition in all three solutions.
DISCUSSION
SDF dissolved to release NH, F and Ag . In DW and DS, NH combined with Ag to form diamminesilver, causing an increase of F and pH. In RS, F reacted with Ca and (PO) to form FAP/CFAP, and Ag reacted with Cl to form AgCl/Ag. These suggests why SDF is effective in managing dentin caries.
PubMed: 38708061
DOI: 10.3389/froh.2024.1374333 -
The Saudi Dental Journal Apr 2024The anatomical configuration classified as Vertucci's type III is described as the second most prevalent in mandibular incisors.
INTRODUCTION
The anatomical configuration classified as Vertucci's type III is described as the second most prevalent in mandibular incisors.
METHODS
Thirty-six Vertucci's type III mandibular incisors were evaluated by micro-computed tomography (micro-CT) and divided into 3 groups (n = 12) according to the root canal preparation protocol (HyFlex CM [HCM], HyFlex EDM [HEDM], and Sequence Rotary File [SRF]). The teeth were scanned before and after performing 0.25 mm and 0.40 mm apical diameter preparations. The canal volume, dentin thickness, percentage of accumulated debris and untouched canal areas, transportation, and centering ability were measured. The data were statistically analyzed by ANOVA, Tukey, Kruskal-Wallis, and Dunn tests (P < 0.05).
RESULTS
The volume increase was more evident in the apical third. After 0.40 mm preparation, the SRF system provided a higher reduction (P < 0.05) in dentin thickness on the buccal surface 1 mm from the apex. There was higher canal transportation in the bucco-lingual direction. The 0.40 mm apical preparation reduced the percentage of untouched canal areas. The apical third had the highest percentage of untouched canal areas. The cervical third had the lowest volume of accumulated debris.
CONCLUSIONS
Increasing the apical preparation to a diameter of 0.40 mm with the HCM, HEDM, and SRF systems in Vertucci's type III root canals of mandibular incisors proved to be safe and effective, reducing untouched canal areas.
CLINICAL RELEVANCE
Root flattening can be intense to the point of generating a root canal bifurcation. Despite the decrease in the root canal diameter, a greater enlargement of the apical region is necessary and safe.
PubMed: 38690376
DOI: 10.1016/j.sdentj.2024.01.010 -
Development of clobetasol-loaded biodegradable nanoparticles as an endodontic intracanal medicament.International Endodontic Journal Apr 2024The aim of current study is the development and optimization of biodegradable polymeric nanoparticles (NPs) to be used in the field of Endodontics as intracanal...
AIM
The aim of current study is the development and optimization of biodegradable polymeric nanoparticles (NPs) to be used in the field of Endodontics as intracanal medication in cases of avulsed teeth with extended extra-oral time, utilizing PLGA polymers loaded with the anti-inflammatory drug clobetasol propionate (CP).
METHODOLOGY
CP-loaded nanoparticles (CP-NPs) were prepared using the solvent displacement method. CP release profile from CP-NPs was assessed for 48 h against free CP. Using extracted human teeth, the degree of infiltration inside the dentinal tubules was studied for both CP-NPs and CP. The anti-inflammatory capacity of CP-NPs was evaluated in vitro measuring their response and reaction against inflammatory cells, in particular against macrophages. The enzyme-linked immunosorbent assay (ELISA) was used to examine the cytokine release of IL-1β and TNF-α.
RESULTS
Optimized CP-NPs displayed an average size below 200 nm and a monomodal population. Additionally, spherical morphology and non-aggregation of CP-NPs were confirmed by transmission electron microscopy. Interaction studies showed that CP was encapsulated inside the NPs and no covalent bonds were formed. Moreover, CP-NPs exhibited a prolonged and steady release with only 21% of the encapsulated CP released after 48 h. Using confocal laser scanning microscopy, it was observed that CP-NPs were able to display enhanced penetration into the dentinal tubules. Neither the release of TNF-α nor IL-1β increased in CP-NPs compared to the LPS control, displaying results similar and even less than the TCP after 48 h. Moreover, IL-1β release in LPS-stimulated cells, decreased when macrophages were treated with CP-NPs.
CONCLUSIONS
In the present work, CP-NPs were prepared, optimized and characterized displaying significant increase in the degree of infiltration inside the dentinal tubules against CP and were able to significantly reduce TNF-α release. Therefore, CP-NPs constitute a promising therapy for the treatment of avulsed teeth with extended extra-oral time.
PubMed: 38687284
DOI: 10.1111/iej.14072 -
BMC Oral Health Apr 2024Dentin hypersensitivity, often occurring after dental treatments or from erosive lesions, is a prevalent patient complaint. This study introduces a paste combining 8%... (Randomized Controlled Trial)
Randomized Controlled Trial Comparative Study
Evaluation and comparison of the effects of a new paste containing 8% L-Arginine and CaCO3 plus KNO3 on dentinal tubules occlusion and dental sensitivity: a randomized, triple blinded clinical trial study.
BACKGROUND
Dentin hypersensitivity, often occurring after dental treatments or from erosive lesions, is a prevalent patient complaint. This study introduces a paste combining 8% L-arginine, calcium carbonate, and potassium nitrate to evaluate its impact on dentinal tubules occlusion, dentin permeability, and tooth sensitivity.
METHODS
Dentin surfaces from 24 third molars (thickness: 2 mm) were divided into two groups of 12. One received the experimental paste, while the other received a placebo without desensitizer. Permeability and sealing ability were assessed through scanning electron microscopy (SEM) and dentin permeability measurement. The pastes' effects on hypersensitivity were then examined in a triple-blind, randomized parallel-armed clinical trial with 16 eligible patients. Sensitivity to cold, touch, and spontaneous stimuli was recorded using the VAS scale at various intervals post-treatment. Statistical analysis was conducted using Shapiro-Wilk, Mann-Whitney U, Friedman, and Wilcoxon tests (α = 0.05).
RESULTS
The permeability test demonstrated a significant reduction in dentin permeability in the experimental group (P = 0.002) compared to the control (P = 0.178). SEM images revealed most dentinal tubules in the intervention samples to be occluded. Clinically, both groups showed a significant decrease in the three types of evaluated sensitivity throughout the study. However, no significant difference in sensitivities between the two groups was observed, with the exception of cold sensitivity at three months post-treatment (P = 0.054).
CONCLUSION
The innovative desensitizing paste featuring 8% L-arginine, calcium carbonate, and potassium nitrate effectively occluded dentinal tubules and reduced dentin permeability. It mitigated immediate and prolonged dentin hypersensitivity to various stimuli, supporting its potential role in managing dentin hypersensitivity.
TRIAL REGISTRATION
http://irct.ir : IRCT20220829055822N1, September 9th, 2022.
Topics: Humans; Dentin Sensitivity; Arginine; Calcium Carbonate; Nitrates; Male; Female; Potassium Compounds; Dentin Desensitizing Agents; Adult; Microscopy, Electron, Scanning; Dentin Permeability; Dentin; Toothpastes; Young Adult; Middle Aged
PubMed: 38685035
DOI: 10.1186/s12903-024-04298-3