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Polymers Jun 2022This in vitro study aimed to examine the shear bond strength of composite on the dentin and enamel substrates when mixed with different composite-handling agents (CHAs)....
This in vitro study aimed to examine the shear bond strength of composite on the dentin and enamel substrates when mixed with different composite-handling agents (CHAs). Eighty extracted molars were embedded into acrylic resin and sectioned sagittally. On the prepared specimens, four groups of resin mixtures were bonded onto the enamel or dentin surfaces—composite only, composite mixed with Composite Wetting Resin (CWR), composite mixed with Brush and Sculpt (BS), and composite mixed with Modeling Resin (MR). All groups were prepared by mixing at a 1:1 ratio by weight. Each specimen was subjected to the shear bond strength test. After the test, adhesive or cohesive failures were examined at the fractured sites. Data were analyzed using one-way and two-way analysis of variance (ANOVA) and the Tukey post hoc test. All composite groups mixed with CHAs displayed a reduced shear bond strength on dentin and enamel substrates compared to composite alone (p < 0.05). The shear bond strength on dentin decreased in the following order: CWR > BS > MR. A similar pattern was observed on enamel, except that there was no statistically significant difference between BS and MR. Statistically significant interactions between resin mixtures and substrates were found (p < 0.001). On the dentin substrate, adhesive failure dominated while adhesive/cohesive failure dominated on the enamel substrate. Conclusions: The shear bonding strength of composite decreases when mixed with CHAs on both dentin and enamel substrates.
PubMed: 35808710
DOI: 10.3390/polym14132665 -
Heliyon Jan 2022Sensi-IP®OG (SIP-OG) and Sensi-IP®FF (SIP-FF) are soluble bioactive glasses developed to treat dentin hypersensitivity and promote remineralization. Evaluation of...
OBJECTIVES
Sensi-IP®OG (SIP-OG) and Sensi-IP®FF (SIP-FF) are soluble bioactive glasses developed to treat dentin hypersensitivity and promote remineralization. Evaluation of their therapeutic potential to reduce dentin hypersensitivity and recover enamel strength was evaluated using standardized in vitro assessments based on simulated use.
METHODS
To assess dentin occlusion a visual occlusion methodology was employed. Dentin discs were subjected to twice-daily simulated brushing (for 5 days) using 0.67 g of toothpaste for 10 s. Simple prototype toothpastes containing SIP-OG and SIP-FF were compared to commercially available controls: Colgate® Sensitive Pro-Relief (CPR) and Sensodyne® Repair and Protect with NovaMin® (SRP). Samples were stored in artificial saliva between treatments. All samples were assessed at baseline and subsequent to each treatment and were scored on a 5-point categorical scale for occlusion. For enamel surface effects, test articles of SIP-OG, SIP-FF, and SIP-FF with NaF were compared to a positive (with NaF) and a negative (no NaF) control paste. Enamel samples were subjected to a pH cycling regime, providing exposure to the toothpaste slurry (i.e., 2 parts deionized water to 1 part toothpaste), mineralizing solution, and demineralizing solution over 5 days of simulated use. Samples were stored overnight in mineralizing solution. Samples were evaluated for fluoride uptake and changes to surface microhardness.
RESULTS
Visual occlusion scores (1 fully occluded to 5 unoccluded) were 2.6, 3.8, 4.4 and 4.0 after 1 day of simulated use for SIP-OG, SIP-FF with NaF, Colgate® Sensitive Pro-Relief and Sensodyne® Repair and Protect, respectively, decreasing to 1.0, 1.8, 3.1 and 3.9 after 5 days of application. SIP-OG provided superior occlusion at the significance level of p ≤ 0.05 at 1, 2, 3, 4, and 5 days. SIP-FF with NaF provided superior occlusion at the significance level of p ≤ 0.05 at 2, 4, and 5 days. Fluoride uptake ranged from 9.0 μg/cm for SIP-OG to 12.4 μg/cm for SIP-FF with NaF. Surface microhardness after acid cycling allowed recovery of 59 % of surface microhardness after treatment with SIP-OG or SIP-FF with NaF. SIP-OG achieved significant surface microhardness recovery versus SIP-FF alone, a NaF control paste, and a fluoride free control paste at the significance level of p ≤ 0.05. SIP-FF with NaF achieved surface microhardness recovery versus SIP-FF alone, a NaF control paste, and a fluoride free control paste at the significance level of p ≤ 0.05.
CONCLUSIONS
Superior occlusion of dentin tubules was observed with both novel additives compared to commercially available toothpastes. A build-up effect with increasing occlusion was noted with repeated application for both novel additives and ascribed to mineralization effects, as supported by surface microhardness recovery on initial enamel lesions.
PubMed: 35036593
DOI: 10.1016/j.heliyon.2021.e08672 -
Influence of Erosion/Abrasion and the Dentifrice Abrasiveness Concomitant with Bleaching Procedures.Clinical, Cosmetic and Investigational... 2020The aim of this study was to evaluate the effect of erosive/abrasive cycles and two different levels of abrasiveness of dentifrices over enamel and dentin subjected to...
PURPOSE
The aim of this study was to evaluate the effect of erosive/abrasive cycles and two different levels of abrasiveness of dentifrices over enamel and dentin subjected to bleaching.
METHODS
Enamel and dentin bovine specimens were prepared and submitted to an at-home bleaching treatment using 9.5% hydrogen peroxide gel, which was applied daily (30 min/14 days). Concomitant with bleaching, an erosive cycle was performed using citric acid (0.3%, pH 3.8, 5 mins, 3×/day), followed by immersions in artificial saliva for remineralization (30 mins). Abrasion was done with two (high and low abrasiveness) dentifrices (2×/day, 120 seconds) after the first and third erosive immersion each day. Enamel and dentin softening were assessed by microhardness and erosive tooth wear by optical profilometry. Data were submitted to repeated measures ANOVA, followed by the Tukey's test with a significance level of 5%.
RESULTS
For the enamel and considering the erosive-abrasive cycle, significant differences were found between the groups tested, the bleaching, and the abrasiveness of the dentifrice tested; however, the final microhardness values were significantly lower than the initial ones. For dentin, differences were found between the eroded/abrasion and the non-eroded/abrasion groups, with the former presenting lower microhardness values compared with the latter. In addition, bleaching decreased the microhardness values only for the highly abrasive dentifrice, and the final values were lower than for the initial ones for all tested groups.
CONCLUSION
The use of high and low abrasiveness dentifrices during bleaching and concomitant with erosion/abrasion cycles is more harmful to dentin than to enamel.
CLINICAL RELEVANCE
Although bleaching is considered a conservative treatment, it can cause deleterious effects to dental hard tissue. The association of an at-home bleaching technique with erosion and high- or low- abrasive dentifrices harms dentin more than enamel.
PubMed: 32280280
DOI: 10.2147/CCIDE.S234716 -
BMC Oral Health Dec 2022The use of silver diamine fluoride (SDF) in caries treatment in children has increased despite the disadvantage of causing tooth discoloration. Nanosilver fluoride (NSF)... (Randomized Controlled Trial)
Randomized Controlled Trial
Antibacterial effect and impact on caries activity of nanosilver fluoride and silver diamine fluoride in dentin caries of primary teeth: a randomized controlled clinical trial.
BACKGROUND
The use of silver diamine fluoride (SDF) in caries treatment in children has increased despite the disadvantage of causing tooth discoloration. Nanosilver fluoride (NSF) is a possible alternative. This study aimed to assess the antibacterial effect of NSF and SDF and their impact on the activity of dentin caries in primary teeth.
METHODS
Synthesis and characterization of the physical and biological properties of NSF were conducted. Fifty children aged 4-6 years with dentin caries (active caries corresponding to ICDAS code 5) in deciduous teeth were randomly assigned to treatment by NSF or SDF. Baseline assessment of Streptococcus mutans (S. mutans) and lactobacilli counts as CFU/mL in caries lesions was done, followed by the application of the agents. After one month, microbiological samples were recollected, and lesion activity was reassessed. Groups were compared using Mann-Whitney and Chi-Square tests, while intragroup comparisons were done using Wilcoxon and McNemar tests. Multilevel logistic regression analysis was used to assess the effect of different variables on the outcomes.
RESULTS
There were 130 teeth in 50 children; mean ± SD age = 4.75 ± 0.76 years, 63% were posterior teeth. At the one-month follow-up appointment, both groups showed a significant decrease from baseline bacterial counts. There was a significant difference in the reduction of S. mutans between NSF and SDF (21.3% and 10.5%, respectively, p = 0.002), while not in lactobacilli (13.9% and 6.0%, respectively, p = 0.094). In both groups, there was a significant reduction in the number of active caries from baseline (p < 0.0001) with no significant difference between groups (percentage inactive = 64.4% and 63.4%, p = 0.903). Multilevel regression revealed non-significant differences in S. mutans and lactobacilli counts (AOR 1.281, p = 0.737 and 1.888, p = 0.341, respectively), and in the number of inactive lesions (AOR 1.355, p = 0.731) between groups.
CONCLUSION
The short-term antibacterial efficacy of NSF was similar to that of SDF. In both groups there was a significant reduction of S. mutans and lactobacilli counts in active dentin caries, and two-thirds of the lesions became inactive with no differences between the two interventions. Further research is needed to investigate the long-term efficacy of NSF and its suitability for clinical use in caries management.
TRIAL REGISTRATION
This trial was prospectively registered on the clinicaltrials.gov registry with ID: NCT05221749 on 03/02/2022.
Topics: Child; Humans; Fluorides; Cariostatic Agents; Dental Caries Susceptibility; Tooth, Deciduous; Fluorides, Topical; Dental Caries; Silver Compounds; Quaternary Ammonium Compounds; Dentin
PubMed: 36585664
DOI: 10.1186/s12903-022-02697-y -
Biomolecules Jul 2021Intracellular Ca signaling engendered by Ca influx and mobilization in odontoblasts is critical for dentinogenesis induced by multiple stimuli at the dentin surface....
Intracellular Ca signaling engendered by Ca influx and mobilization in odontoblasts is critical for dentinogenesis induced by multiple stimuli at the dentin surface. Increased Ca is exported by the Na-Ca exchanger (NCX) and plasma membrane Ca-ATPase (PMCA) to maintain Ca homeostasis. We previously demonstrated a functional coupling between Ca extrusion by NCX and its influx through transient receptor potential channels in odontoblasts. Although the presence of PMCA in odontoblasts has been previously described, steady-state levels of mRNA-encoding PMCA subtypes, pharmacological properties, and other cellular functions remain unclear. Thus, we investigated PMCA mRNA levels and their contribution to mineralization under physiological conditions. We also examined the role of PMCA in the Ca extrusion pathway during hypotonic and alkaline stimulation-induced increases in intracellular free Ca concentration ([Ca]). We performed RT-PCR and mineralization assays in human odontoblasts. [Ca] was measured using fura-2 fluorescence measurements in odontoblasts isolated from newborn Wistar rat incisor teeth and human odontoblasts. We detected mRNA encoding PMCA1-4 in human odontoblasts. The application of hypotonic or alkaline solutions transiently increased [Ca] in odontoblasts in both rat and human odontoblasts. The Ca extrusion efficiency during the hypotonic or alkaline solution-induced [Ca] increase was decreased by PMCA inhibitors in both cell types. Alizarin red and von Kossa staining showed that PMCA inhibition suppressed mineralization. In addition, alkaline stimulation (not hypotonic stimulation) to human odontoblasts upregulated the mRNA levels of dentin matrix protein-1 (DMP-1) and dentin sialophosphoprotein (DSPP). The PMCA inhibitor did not affect DMP-1 or DSPP mRNA levels at pH 7.4-8.8 and under isotonic and hypotonic conditions, respectively. We also observed PMCA1 immunoreactivity using immunofluorescence analysis. These findings indicate that PMCA participates in maintaining [Ca] homeostasis in odontoblasts by Ca extrusion following [Ca] elevation. In addition, PMCA participates in dentinogenesis by transporting Ca to the mineralizing front (which is independent of non-collagenous dentin matrix protein secretion) under physiological and pathological conditions following mechanical stimulation by hydrodynamic force inside dentinal tubules, or direct alkaline stimulation by the application of high-pH dental materials.
Topics: Animals; Calcium; Cell Line; Dentin; Humans; Odontoblasts; Plasma Membrane Calcium-Transporting ATPases; Rats; Rats, Wistar; Tooth Calcification
PubMed: 34356633
DOI: 10.3390/biom11071010 -
Journal of Dentistry Jan 2021To evaluate the incorporation of doxycycline (DOX) into a commercial dental adhesive regarding physicochemical properties, microtensile bond strength (μTBS),...
OBJECTIVES
To evaluate the incorporation of doxycycline (DOX) into a commercial dental adhesive regarding physicochemical properties, microtensile bond strength (μTBS), nanoleakage (NL), nanohardness (NH) and Young's modulus (YM), metalloproteinases (MMP) inhibition, and antibiofilm activity.
METHODS
DOX was incorporated into the adhesive at 0.05, 0.1, 0.5, and 1 wt%. Restored teeth were evaluated for μTBS, NL, NH, and YM after 24 -hs and 1-year of water storage. Biofilms of Streptococcus mutans were grown on top of these adhesives and determined for bacterial viability and amount of biomass. The inhibitory effect on MMP was analyzed by in situ zymography under confocal microscopy.
RESULTS
Adhesives with 0.5 and 1 wt% of DOX presented reduced pH and degree of conversion. The incorporation of DOX did not affect μTBS and hybrid layer YM. The control group (no DOX) had a decrease in μTBS and the densest silver nitrate areas after 1-year storage. Hybrid layer NH values increased with 0.1 wt% DOX compared to control and 1 wt% DOX groups, at 24 -hs. After 1-year storage, NH of 1 wt% DOX adhesive decreased compared to the control group. The 0.5 and 1 wt% concentrations of DOX decreased the bacterial viability and the biofilm biomass. Confocal images suggest an increased MMP inhibition proportional to the percentage of DOX.
CONCLUSION
At any concentration, DOX-doped dental adhesives were able to inhibit MMP activity, diminish nanoleakage, and maintain the resin-dentin bond-strength after 1 year of artificial aging.
CLINICAL SIGNIFICANCE
Doxycycline-doped dental adhesive inhibited metalloproteinases activity and preserved interface bond strength. This formulation has a potential to improve adhesive restorations clinical longevity.
Topics: Biofilms; Dental Bonding; Dental Cements; Dentin; Dentin-Bonding Agents; Doxycycline; Humans; In Vitro Techniques; Materials Testing; Metalloproteases; Molar; Resin Cements; Tensile Strength
PubMed: 33276081
DOI: 10.1016/j.jdent.2020.103550 -
BMC Oral Health Apr 2024The stability of resin-dentin interfaces is still highly questionable. The aim of this study was to evaluate the effect of Salvadora persica on resin-dentin bond...
BACKGROUND
The stability of resin-dentin interfaces is still highly questionable. The aim of this study was to evaluate the effect of Salvadora persica on resin-dentin bond durability.
MATERIALS AND METHODS
Extracted human third molars were used to provide mid-coronal dentin, which was treated with 20% Salvadora persica extract for 1 min after acid-etching. Microtensile bond strength and interfacial nanoleakage were evaluated after 24 h and 6 months. A three-point flexure test was used to measure the stiffness of completely demineralized dentin sticks before and after treatment with Salvadora persica extract. The hydroxyproline release test was also used to measure collagen degradation by endogenous dentin proteases. Statistical analysis was performed using two-way ANOVA followed by post hoc Bonferroni test and unpaired t-test. P-values < 0.05 were considered statistically significant.
RESULTS
The use of Salvadora persica as an additional primer with etch-and-rinse adhesive did not affect the immediate bond strengths and nanoleakage (p > 0.05). After 6 months, the bond strength of the control group decreased (p = 0.007), and nanoleakage increased (p = 0.006), while Salvadora persica group showed no significant difference in bond strength and nanoleakage compared to their 24 h groups (p > 0.05). Salvadora persica increased dentin stiffness and decreased collagen degradation (p < 0.001) compared to their controls.
CONCLUSION
Salvadora persica extract pretreatment of acid-etched dentin preserved resin-dentin bonded interface for 6 months.
CLINICAL SIGNIFICANCE
Durability of resin-dentin bonded interfaces is still highly questionable. Endogenous dentinal matrix metalloproteinases play an important role in degradation of dentinal collagen within such interfaces. Salvadora persica may preserve resin-dentin interfaces for longer periods of time contributing to greater clinical success and longevity of resin composite restorations.
Topics: Humans; Dentin; Tensile Strength; Plant Extracts; Dental Bonding; Dental Leakage; Salvadoraceae; Acid Etching, Dental; Collagen; Dentin-Bonding Agents; Materials Testing; Hydroxyproline; Dental Stress Analysis; Composite Resins; Time Factors; Resin Cements
PubMed: 38684974
DOI: 10.1186/s12903-024-04244-3 -
Journal of Dental Sciences Jan 2023The root fracture resistance of endodontically treated teeth is decreased significantly, and it is more likely to fracture. This study aimed to evaluate the effect of a...
BACKGROUND/PURPOSE
The root fracture resistance of endodontically treated teeth is decreased significantly, and it is more likely to fracture. This study aimed to evaluate the effect of a novel root canal sealer based on bioactive glass (BG) on root fracture resistance and explore its mechanism.
MATERIALS AND METHODS
The BG-based root canal sealer (BG Sealer) was prepared by mixing a kind of bioactive glass (10.8% PO, 54.2% SiO, 35% CaO, mol.%, named PSC), zirconia (ZrO) powder, sodium alginate (SA) and phosphate solution (PS). A pH meter was used to measure the pH of simulated body fluid (SBF) after immersion with BG Sealer at different time. After preparing the samples of BG sealer with a diameter of 4 mm and a height of 6 mm, the compressive strength was tested by a universal testing machine. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to detect and analyze the mineral status of root canal systems filled with BG Sealer. The push out test was used to measure the push out bond strength of BG Sealer. The fracture resistance of root canals filled with BG Sealer was detected by the compressive loading test. Bioceramic root canal sealer iRoot SP was set as the control group.
RESULTS
(1) Physicochemical properties: The pH value of SBF immersed with BG Sealer increased slightly up to 7.68, while the pH of SBF immersed with iRoot SP increased to 12.08. The compressive strength of the novel BG Sealer was 4.62 ± 1.70 MPa, which was lower than that of iRoot SP ( < 0.05). (2) Mineralization: The hydroxyapatite layers were observed on the surface of BG Sealer and iRoot SP after being immersed in SBF for 4 weeks. BG Sealer and iRoot SP were both able to penetrate into the dentin tubules, duplicate the morphology of root canals well, and form a layer of hydroxyapatite. (3) Adhesion to dentin: There was no significant difference between the push out bond strength of the novel BG Sealer and iRoot SP ( > 0.05). (4) Fracture resistance: After immersion in SBF for 4 weeks, the fracture resistance of roots filled with BG Sealer and iRoot SP was 454.16 ± 155.39 N and 445.50 ± 164.73 N, respectively, both of which were not statistically different from that of the roots unprepared and unfilled (394.07 ± 62.12 N) ( > 0.05), whereas higher than that of the roots prepared and unfilled (235.36 ± 83.80 N) ( < 0.05).
CONCLUSION
The novel BG Sealer has good adhesion to the root dentin, can penetrate into the dentin tubules to generate minerals, and meanwhile can improve the fracture resistance of the roots after root canal treatment. It is expected to be a bioactive root canal sealer with good clinical application prospects.
PubMed: 36643269
DOI: 10.1016/j.jds.2022.08.004 -
Iranian Endodontic Journal 2021The aim of our systematic review was to assess the impact of gutta-percha solvents on the bond strength of endodontic sealers to intraradicular dentin using the push-out... (Review)
Review
INTRODUCTION
The aim of our systematic review was to assess the impact of gutta-percha solvents on the bond strength of endodontic sealers to intraradicular dentin using the push-out bond test.
METHODS AND MATERIALS
The literature was searched in databases (PubMed, Web of Science and Scopus) up to September 2020, using the following search terms: (bond strength AND solvent* AND sealer* AND (tooth root OR dentin OR retreatment OR root canal). No date limits were implemented, and English languages were included. The question research was constructed based on the PICO () strategy: "Does gutta-percha solvents effect the bond strength of sealers to intraradicular dentin?". The studies were analyzed by two reviewers and were included if they utilized extracted permanent human teeth with completely formed apices, as well as assessed the influence of gutta-percha solvents on the bond strength of sealers to intraradicular dentin using push-out bond test. Review articles, case reports and studies that included immature, bovine or artificial teeth were excluded. The risk of bias was evaluated based on the Cochrane criteria adopted to studies.
RESULTS
Thirty-two papers were analyzed, seven accomplished the eligibility criteria and were selected for our systematic review. The global risk of bias was high. Due to variations in the methodological variables, a meta-analysis could not be performed.
CONCLUSION
Our systematic review highlighted the adverse effect of chloroform, which decreased the bond strength of different sealers, and the generally higher bond strength of epoxy resin-based sealers, detected with the push-out bond test. We recommend the standardization of methods in future studies to obtain a more definitive conclusion about the influence of solvents on the bond strength of sealers to intraradicular dentin.
PubMed: 36704416
DOI: 10.22037/iej.v16i1.29297 -
Journal of Dental Sciences Jul 2022Recently, metal-free restoration has become the standard in prosthetic treatment. However, it is still unclear which combination is most effective in preventing root...
BACKGROUND/PURPOSE
Recently, metal-free restoration has become the standard in prosthetic treatment. However, it is still unclear which combination is most effective in preventing root fracture and secondary caries. The purpose of this study was to evaluate the influence of different post systems, crown materials, crown thickness and luting agents on the stress distribution around the crown margins, cervical dentin and the tip of the post.
MATERIALS AND METHODS
Ninety-six mandibular first premolar models were developed and analyzed using finite element analysis (FEA). Two designs of crowns, six kinds of crown materials, four types of post and core systems and two kinds of luting agents were included and evaluated for the stress distribution within the abutment teeth. The Von Mises stress magnitudes were compared among all models.
RESULTS
The stress at the tip of the post decreased as the young's modulus of luting agent decreased; The stress concentrated more at the cervical area (dentin and crown), as the physical properties of the crown material increased.
CONCLUSION
Crowns fabricated using polyetheretherketone (PEEK) can reduce the stress concentration at the cervical area, so it may be possible to reduce the amount of tooth reduction during abutment tooth preparation. The stress distribution around the post tip is affected by the post and core systems and luting agent, regardless of crown materials and thickness. When inserting a post of the higher Young's modulus such as zirconia post, methyl methacrylate luting cement can reduce the stress concentration at the tip of the post.
PubMed: 35784123
DOI: 10.1016/j.jds.2022.01.015