Dentinal Fluid Research Articles

Comparison of Class II Bulk-Fill, Self-Adhesive Composites, Alkasite, and High-Viscosity Glass Ionomer Restorations in Terms of Marginal and Internal Adaptation.

(1) Background: Restoring decayed teeth in young patients can be challenging. This calls for a simplification of the protocols through new biomaterials. Therefore, the aim of this study was to compare the marginal adaptation delivered by restorative materials applied on class II cavities by using a simplified protocol, before and after fatigue test, followed by the assessment of the internal adaptation. (2) Methods: Forty-eight human teeth were divided into six groups (n = 8). Dentinal fluid simulation was performed before restoring the class II cavities: Gr 1-adhesive (Clearfil Universal Bond Quick) and nanohybrid flowable composite (Clearfil Majesty ES Super Low Flow), Gr 2-adhesive (Clearfil Universal Bond Quick) and nanohybrid composite (Clearfil Majesty ES standard), Gr 3-bulk fill self-adhesive composite (Surefil One), Gr 4-bioactive powder-liquid filling material (Cention Forte), Gr 5-universal adhesive (Adhese Universal) and nanohybrid composite resin (Tetric Powerfill); and control group (CT)-high-viscosity glass ionomer (Equia Forte). Marginal adaptation was observed with scanning electron microscopy (SEM) and compared before and after a fatigue test consisting of repeated thermal and mechanical cycles. The specimens were then cut mesio-distally, and internal adaptation was undertaken using SEM again. Repeated measures and one way ANOVA followed by a Fisher's LSD test and Fisher's LSD post hoc test were used in order to compare the statistically significant differences among groups. (3) Results: As for the marginal adaptation after loading, Cention Forte (58%) and Equia Forte HT (53%) were statistically equivalent and presented the highest results, followed by Clearfil Majesty ES Standard (32%) and Tetric Powerfill (27%), with Surefil One (8%) and Clearfil Majesty ES Flow Super Low (7%) showing the worst results. In terms of internal adaptation, Cention Forte (85%) and Clearfil Majesty ES Standard (74%) had the highest percentages of continuous margins. Tetric powerfill (56%) and Equia Forte HT (44%) showed statistically significantly lower results, followed by Clearfil Majesty ES Flow Super Low (33%) and eventually Surefil One (17%). (4) Conclusions: This in vitro study showed promising results for the marginal and internal adaptation of alkasite dual cured Cention Forte in the restoration of class II cavities. This material could be considered an interesting restorative alternative for the restoration of deciduous teeth.

The effect of immediate dentin sealing on the bond strength of resin composite to dentin bonded with universal bonding agent: An in vitrostudy

Background:Dentin hypersensitivity is a common scenario encountered in dental practice. This issue can be treated by reducing dentin permeability and dentinal fluid flow. However, the desensitizing agents used may adversely affect the bonding of composite restorations to dentin.Aim:To evaluate the shear bond strength of restorative composites to dentin treated with silver diamine fluoride and self-etch bonding agent bonded using a universal bonding agent.Materials and methods:A total of 30 teeth were selected, and their occlusal surfaces were ground to expose a flat dentin surface. The teeth were then embedded in cold cure resin blocks. Depending on the treatment, the samples were randomly divided into three groups, with 10 in each. The samples in the group were untreated, in group 2 were treated with Silver Diamine Fluoride (SDF), and in group 3 with the sixth generation bonding agent (self-etch primer). After the treatment, the composite is bonded to the dentin surfaces and subjected to shear bond strength using the universal testing machine (UTM). The specimen was mounted on the custom-made jig and placed over the UTM. The load was applied at a cross-head speed of 1mm/min until debonding occurred at the dentin and composite interface, and the bond strength was computed in MPa. Overall comparisons were analyzed using the Kruskal-Wallis test. The Mann-Whitney U-test was used for pair-wise comparisons, and the significance level was set at p < 0.05.Results:The lowest bond strength was observed with the dentin surfaces treated with silver diamine fluoride (Group 2), and the highest bond strength was for dentin treated with self-etchbonding agent (Group3). Significant differences (p=0.003) were observed between the groups. In pair-wise comparisons, group 3 showed significant difference with group 1 (p=0.007) and group 2 (p=0.002). However, no significant difference was observed between groups 1 and 2 (p=0.197).Conclusion:The shear bond strength varies with different desensitizing treatments. This study reported more SBS with sixth-generation bonding agent followed by untreated dentin and SDF.

POSTOPERATIVE SENSITIVITY IN POSTERIOR COMPOSITE RESIN RESTORATIONS

Composite resin restorations are part of everyday clinical practice, delivering aesthetic and long-lasting results, provided there is mastery of the technique and knowledge of dental materials. Among the main failures in composite resin restorations is postoperative sensitivity, which causes discomfort for both the patient and the dentist due to the need to redo the procedure. The aim of this study is to demonstrate, through the literature, the possible origins of postoperative sensitivity and to describe more effective methods to minimize it. A literature review was conducted, with a temporal focus on the last 10 years (2013–2023), where articles published on the topic were searched in the PubMed, Scielo, Google Scholar, Scribd, and Lilacs databases. Postoperative sensitivity occurs due to the movement of existing dentinal fluids in the dentin, caused by inadequate sealing of dentinal tubules. Procedure failure is associated with factors such as restorative technique, adhesive system, monomer conversion rate, and polymerization time, which can lead to postoperative sensitivity. Thus, postoperative sensitivity can be triggered by various factors during the clinical procedure, requiring attention at every stage of the restorative technique by the dentist

Intratubular crystal formation in the exposed dentin from nano-sized calcium silicate for dentin hypersensitivity treatment

The aim of this study is to evaluate intratubular crystal formation from the experimental material consisting of dicalcium silicate (C2S) and tricalcium silicate (C3S) with nano-scaled particle size. A total of twenty-four specimens were made by isolating 8 mm of the cervical part centered at the cementoenamel junction of extracted premolars. Twelve specimens were not treated and considered as control. The experimental material was applied to the other twelve specimens by brushing for 10,000 strokes. Each group was randomly divided into four subgroups according to the period of immersion in phosphate buffer saline (PBS) for 1, 30, 60, and 90 days each. The specimens were sectioned longitudinally and examined with scanning electron microscopy and energy dispersion X-ray spectroscopy. The intratubular crystal were formed in PBS and densely filled the dentinal tubules over time. The crystal formation occurred at a depth of more than 50 μm from the dentin surface. The Ca/P ratio of formed intratubular crystals was 1.68 after 3 months. The experimental material consisting of C2S and C3S with a nanoscale particle size can form hydroxyapatite-like crystals in dentinal tubules in PBS, and there is a possibility of reducing dentin hypersensitivity by blocking the dentinal fluid flow.

Hydrodynamics of dental dentinal fluid

Hydrodynamics of dental dentinal fluid

Evaluation of Post-Cementation Sensitivity After Cementation with Bio-Active Luting Cement - A Randomized Clinical Control Trial

Background The most common complaint following cementation is the occurrence of post cementation sensitivity. The sensitivity to cold stimulus after cementation can be indicative of a gap present below the crown or a marginal gap connecting to opened tubules which emerge into the pulp. A pulp fluid outflow occurs as a result of the contraction of dentinal fluid in this gap which causes postoperative sensitivity. Thus luting agents should form complete seal between fabricated restoration and prepared tooth.Objectives The current study was conducted to clinically evaluate post-cementation hypersensitivity of bioactive luting cement in a randomized clinical control trial using resin modified glass ionomer cement RMGIC as the control.Methods According to standard tooth preparation protocol the teeth were prepared to receive Porcelain fused to metal PFM bridges on both sides of the mouth. PFM final restorations were cemented using Bioactive and RMGIC luting cement. Sensitivity was tested by using compressed airbiting pressure tests and cold water and was evaluated by using Schiff scale with 0-3 scores before cementation soon after cementation one week and three months post cementation.Results Almost all the patients responded to hypersensitivity at pre-cementation and baseline with compressed airbiting pressure tests and cold water. The sensitivity scores reduced over time one week and three months for both the luting agents.Conclusion Based on the results it can be concluded that the bioactive luting cement exhibited lesser sensitivity scores when compared to resin modified GIC luting cement.

Self-propelled bioglass janus nanomotors for dentin hypersensitivity treatment.

Dentin hypersensitivity treatment is not always successful owing to the exfoliation of the blocking layer. Therefore, efficiently delivering a desensitization agent into the dental tubule is critical. Nanomotors are widely used as in vivo drug delivery systems owing to their strong power and good biocompatibility. Herein, we report a kind of self-propelled bioglass Janus nanomotor with a Pt motion unit (nBGs@Pt) for application in dentin hypersensitivity that was prepared via a simple sol-gel method and magnetron sputtering method, with an average size of 290 nm. The Pt layer as the power unit provided the dynamics to deliver the bioglass (desensitization agent). Using hydrogen peroxide as a fuel, the nBGs@Pt could automatically move in different media. In addition, the nBGs@Pt with a mesoporous structure demonstrated good hydroxyapatite formation performance. An in vitro dentin pressure model was used to verify the blocking ability of the nBGs@Pt in dentin tubules. The dynamics of the nBGs@Pt was sufficient to resist the outflow of dentin fluid and movement into the dentin tubules, with a blocking rate of 58.05%. After remineralization, the blocking rate could reach 96.07% and the formation of hydroxyapatite of up to 10 μm or more occurred. It is expected that this study will provide a simple and feasible new strategy for the painless treatment of dentin sensitivity.

Piezo1-pannexin-1-P2X3 axis in odontoblasts and neurons mediates sensory transduction in dentinal sensitivity.

According to the "hydrodynamic theory," dentinal pain or sensitivity is caused by dentinal fluid movement following the application of various stimuli to the dentin surface. Recent convergent evidence in Vitro has shown that plasma membrane deformation, mimicking dentinal fluid movement, activates mechanosensitive transient receptor potential (TRP)/Piezo channels in odontoblasts, with the Ca2+ signal eliciting the release of ATP from pannexin-1 (PANX-1). The released ATP activates the P2X3 receptor, which generates and propagates action potentials in the intradental Aδ afferent neurons. Thus, odontoblasts act as sensory receptor cells, and odontoblast-neuron signal communication established by the TRP/Piezo channel-PANX-1-P2X3 receptor complex may describe the mechanism of the sensory transduction sequence for dentinal sensitivity. To determine whether odontoblast-neuron communication and odontoblasts acting as sensory receptors are essential for generating dentinal pain, we evaluated nociceptive scores by analyzing behaviors evoked by dentinal sensitivity in conscious Wistar rats and Cre-mediated transgenic mouse models. In the dentin-exposed group, treatment with a bonding agent on the dentin surface, as well as systemic administration of A-317491 (P2X3 receptor antagonist), mefloquine and 10PANX (non-selective and selective PANX-1 antagonists), GsMTx-4 (selective Piezo1 channel antagonist), and HC-030031 (selective TRPA1 channel antagonist), but not HC-070 (selective TRPC5 channel antagonist), significantly reduced nociceptive scores following cold water (0.1ml) stimulation of the exposed dentin surface of the incisors compared to the scores of rats without local or systemic treatment. When we applied cold water stimulation to the exposed dentin surface of the lower first molar, nociceptive scores in the rats with systemic administration of A-317491, 10PANX, and GsMTx-4 were significantly reduced compared to those in the rats without systemic treatment. Dentin-exposed mice, with somatic odontoblast-specific depletion, also showed significant reduction in the nociceptive scores compared to those of Cre-mediated transgenic mice, which did not show any type of cell deletion, including odontoblasts. In the odontoblast-eliminated mice, P2X3 receptor-positive A-neurons were morphologically intact. These results indicate that neurotransmission between odontoblasts and neurons mediated by the Piezo1/TRPA1-pannexin-1-P2X3 receptor axis is necessary for the development of dentinal pain. In addition, odontoblasts are necessary for sensory transduction to generate dentinal sensitivity as mechanosensory receptor cells.

Iontophoresis effects of two-step self-etch and total-etch systems on dentin permeability and sealing of composite restoration under simulated pulpal pressure.

Studies demonstrated the bond strength enhancement and the decrease in degradation of the adhesive interface after applying either self-etch adhesives or two-step, etch-and-rinse adhesives under an electric field. However, the presence of dentinal fluid driven by the pulpal pressure in vivo is a profounding factor affecting both the sealing ability and bond strength of adhesives. This study aimed to evaluate the effect of three-step etch-and-rinse and two-step self-etch adhesives when applied with iontophoresis under simulated pulpal pressure on the permeability of dentin, resin infiltration, and the sealing ability of resin composite. The experiments were done on 32 recently extracted premolars, randomly assigned into four groups (n = 8) according to two adhesive systems (SBMP and SE), applied following the manufacturer's instructions (control) for two groups or with iontophoresis for the others (SBMPi and SEi). For the iontophoresis, the anodal current was applied at 75μA for 20s through the cavity electrode during the bond. The fluid flow rate of dentin was recorded after cavity preparation (smear-layer-covered dentin; T1), bonding (T2), and composite restoration (T3) during the maintained pulpal pressure of 20mmHg. The flow rates were expressed as a percentage relative to the initial smear-layer-covered value for each specimen. Results were analyzed using repeated measures ANOVA. Scanning electron microscopy (SEM) was performed to observe the resin/dentin interface. There were no significant increases in the mean flow rates from T1 to T3 in the SBMP (P = 0.355), while these changes in the SE were significant between T1 (100%) and T2 (166.77%) and T1 and T3 (221.16%) (P = 0.002; one-way RM ANOVA; Holm-Sidak test). For the iontophoresis groups, the mean flow rates decreased significantly from T1 to T2 and T1 to T3 of both SBMPi (T2 = 86.43, and T3 = 79.53; P < 0.001) and SEi groups (T2 = 87.96, and T3 = 81.48; P = 0.004). The iontophoresis of both adhesives produced the optimal resin infiltration with improved quality of the hybrid layer and resin tags. SBMP bonded with or without iontophoresis performed better sealing ability than SE under the same condition. Both adhesives applied with anodal iontophoresis significantly decreased the dentin permeability, contributing to the improved resin infiltration.

Material properties and bioactivity of a resin infiltrant functionalized with polyhedral oligomeric silsesquioxanes.

To investigate the effect of methacrylate polyhedral oligomeric silsesquioxanes (POSS-8) on various material properties and mineral precipitation potential of a resin infiltrant. A TEGDMA-based resin infiltrant was mixed with 0.5, 1, 3, 5 or 10wt% POSS-8 or left unchanged (control). Degree of conversion (DC), water sorption (WS), viscosity, elastic modulus (E-modulus), flexural strength (FS), Knoop microhardness (KHN) and softening ratio (SR) were assessed. Growth of calcium phosphate (Ca/P) precipitates infiltrant-treated bovine enamel and dentin specimens immersed in artificial saliva or artificial dentinal fluid, respectively, for 28 days was analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. For viscosity assessment, pure TEGDMA filled with 0-10wt% POSS-8 was used. Statistical analyses were performed using ANOVA and Tukey's post-hoc tests (p<0.05). POSS-8 did not change the flexural strength, water sorption and softening ratio. The apparent degree of conversion was increased at lower concentrations only while E-modulus remained constant in almost all groups. The particles led to a slight decrease of KHN at concentrations below 3%. The effect on viscosity is comparable to the reinforcement effect. Ca/P precipitates formed on dentin specimens treated with POSS-8-filled infiltrant after 4 weeks of immersion, but were not detected on the control infiltrant. The mineral precipitation on enamel was not improved by POSS-8. POSS-8 particles did not worsen the material properties of the resin infiltrant, while the Ca/P precipitation on dentin was stimulated.

Desensitizing toothpastes for dentin sealing and tertiary dentin formation in vitro and in vivo: a comparative analysis

BackgroundDentin hypersensitivity is a painful response to external stimuli applied to exposed dentinal tubules. Various toothpastes with active desensitizing ingredients for the relief of dentin hypersensitivity are commercially available. However, data from several studies suggest that the effects of desensitizing toothpastes are unstable and brief. This study aimed to investigate the effect of toothpastes containing CPNE7-derived oligopeptide (CPNE7-DP) and other active desensitizing ingredients in the dentin microleakage, tubule occlusion and tertiary dentin formation.MethodsUsing scanning electron microscopy (SEM), we evaluated the patency of dentinal tubules on the surface of human dentin disks after brushing experiments with the various toothpastes. Dentin was histologically evaluated in a hypersensitivity model of canine teeth, after the exposed dentin area was brushed for 6 weeks. The toothpaste used in group 1 (control) did not contain any desensitizing ingredients; that used in group 2 contained CPNE7-DP; Colgate Sensitive was used in group 3; and Sensodyne Rapid Relief was used in group 4. Finally, we conducted microleakage analysis to investigate the dentin sealing effect. The microleakage analysis data were subjected to one-way ANOVA and post-hoc Tukey tests (alpha = 0.05).ResultsIn the SEM images, all four groups of teeth exhibited partial occlusion of the dentinal tubules on the tooth surface. In the in vivo hypersensitivity model, group 2 exhibited a newly formed tertiary dentin, whereas no new hard tissue formation was observed in groups 1, 3, and 4. Microleakage analysis revealed that the volume of dentinal fluid flow was significantly smaller in group 2 than in group 1.ConclusionsThese results indicate that CPNE7-DP is a promising active ingredient with long-term dentin sealing effects.

Effectiveness and cytotoxicity of two desensitizing agents: a dentin permeability measurement and dentin barrier testing in vitro study

BackgroundWhen evaluating the efficacy and safety of various desensitizing products in vitro, their mechanism of action and clinical utility should be considered during test model selection. This study aimed to evaluate the effects of two desensitizers, an in-office use material and an at-home use material, on dentin specimen permeability, and their dentin barrier cytotoxicity with appropriate test models.MethodsTwo materials, GLUMA desensitizer (GLU) containing glutaraldehyde and remineralizing and desensitizing gel (RD) containing sodium fluoride and fumed silica, were selected. Human dentin specimens were divided into three groups (n = 6): in groups 1 and 2, GLU was applied, and in group 3, RD was applied and immersed in artificial saliva (AS) for 24 h. Dentin specimen permeability before and after each treatment/post-treatment was measured using a hydraulic device under a pressure of 20 cm H2O. The perfusion fluid was deionized water, except in group 2 where 2% bovine serum albumin (BSA) was used. The representative specimens before and after treatment from each group were investigated using scanning electron microscopy. To measure cytotoxicity, test materials were applied to the occlusal surfaces of human dentin disks under which three-dimensional cell scaffolds were placed. After 24-h contact within the test device, cell viability was measured via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays.ResultsGLU significantly reduced the dentin permeability and occluded the dentinal tubules when 2% BSA was used as perfusion fluid. RD significantly reduced dentin permeability and occluded the tubules, but permeability rebounded after AS immersion. GLU significantly decreased cell viability, but RD was non-cytotoxic.ConclusionsIn vitro GLU application induced effective dentinal tubule occlusion only following the introduction of simulated dentinal fluid. RD provided effective tubule occlusion, but its full remineralization potential was not realized after a short period of immersion in AS. GLU may harm the pulp, whereas RD is sufficiently biocompatible.

Effect of Dentin Desensitizer Containing Novel Bioactive Glass on the Permeability of Dentin.

The objective of this study was to evaluate the effect of novel bioactive glass (BAG)-containing desensitizers on the permeability of dentin. Experimental dentin desensitizers containing 3 wt% BAG with or without acidic functional monomers (10-MDP or 4-META) were prepared. A commercial desensitizer, Seal & Protect (SNP), was used as a control. To evaluate the permeability of dentin, real-time dentinal fluid flow (DFF) rates were measured at four different time points (demineralized, immediately after desensitizer application, after two weeks in simulated body fluid (SBF), and post-ultrasonication). The DFF reduction rate (ΔDFF) was also calculated. The surface changes were analyzed using field emission scanning electron microscopy (FE-SEM). Raman spectroscopy was performed to analyze chemical changes on the dentin surface. The ΔDFF of the desensitizers containing BAG, BAG with 10-MDP, and BAG with 4-META significantly increased after two weeks of SBF storage and post-ultrasonication compared to the SNP at each time point (p < 0.05). Multiple precipitates were observed on the surfaces of the three BAG-containing desensitizers. Raman spectroscopy revealed hydroxyapatite (HAp) peaks on the dentin surfaces treated with the three BAG-containing desensitizers. Novel BAG-containing dentin desensitizers can reduce the DFF rate about 70.84 to 77.09% in the aspect of reduction of DFF through the HAp precipitations after two weeks of SBF storage.

Lack of Fluid Movement between Dentin Tubule and Pulp Tissue: An In Vitro Study

Objective: In vitro studies supporting the hydrodynamic theory have reported that cavity provocation results in fluid flow from dentin tubules via pulp tissue to a capillary connected apically. Our preliminary findings did not corroborate this. Therefore, the aim was to perform experiments closely following the descriptions in the mentioned articles to find out if there is a direct fluid flow communication from a prepared cavity to pulp tissue detectable with this method. Material and Methods: Class V cavities were prepared and provocations (air blast, scraping, temperature change) initiated within 1 hour of extraction in 17 teeth and after 1 week in 3 teeth. Fluid flow was monitored during and after stimulation using a microscope. Results: No fluid flow was registered during stimulations performed within an hour of extraction. One week after extraction fluid movement was registered during the air blast. Conclusions: The finding of no direct continuum in freshly extracted teeth from cavity surface via dentin fluid to pulp tissue to an apically placed capillary does not per se disprove the hydrodynamic theory. As the in vitro experiment by Brännström et al. has been a major foundation for the hydrodynamic theory, it may be time to investigate the true mechanism(s) of dentin sensitivity.

The nature of metabolic processes in human dental hard tissues depending on their morphological structure

Was to give a comparative assessment of the movement of enamel and dentin fluid depending on the morphological structure of different sections of human dental hard tissues. The research involved 140 female subjects aged 21-30 years. Sizes, form, surface of enamel-dentin junction, enamel prisms and their crystals in superficial, middle and deep sections, width, tortuosity, facing of dentin tubules of tested teeth were analyzed by scanning electron microscope Jeol JCM-5700 and atomic force microscope NTEGRA Prima. The biochemical study examined the quantitative content of water in the samples of enamel, dentin, enamel-dentin junction by weighing sample weights before and after drying. The data obtained were processed by methods of variation statistics using standard packages Microsoft Excel 2008, Statistica 12.0. The enamel-dentine junction of large-fastened type is characterized by zones of dentin integration into enamel at the distance of more than 10 mm, with regular arrangement of enamel prisms and wide dentine tubules of 3.55 to 4.70 μm in diameter; no water content reduction was found. The small-fastened type has less pronounced spots of dentin interference with enamel from 2 to 10 μm, the dentinal tubules are slightly curved with a diameter of 2.90 to 3.60 μm, the water content in dentin is reduced. In microfastened type, a linear structure with interpenetration zones up to 2 μm, enamel prisms slightly ordered, dentin tubules narrowed and curved in diameter from 1.30 to 1.95 μm, water content in enamel and dentin is reduced. At microfastened type of enamel-dentin junction, chaotic arrangement of enamel prisms and narrow dentin tubules water movement is broken and metabolic processes are reduced that determines high probability of exposure of dental hard tissue diseases.

Effect of Novel Bioactive Glass-Containing Dentin Adhesive on the Permeability of Demineralized Dentin.

This study aimed to evaluate the effect of a novel bioactive glass (BAG)-containing dentin adhesive on the permeability of demineralized dentin. Bioactive glass (85% SiO2, 15% CaO) was fabricated using the sol-gel process, and two experimental dentin adhesives were prepared with 3 wt% silica (silica-containing dentin adhesive; SCA) or BAG (BAG-containing dentin adhesive; BCA). Micro-tensile bond strength (μTBS) test, fracture mode analysis, field-emission scanning electron microscopy (FE-SEM) analysis of adhesive and demineralized dentin, real-time dentinal fluid flow (DFF) rate measurement, and Raman confocal microscopy were performed to compare SCA and BCA. There was no difference in μTBS between the SCA and BCA (p > 0.05). Multiple precipitates were evident on the surface of the BCA, and partial occlusion of dentinal tubules was observed in FE-SEM of BCA-approximated dentin. The DFF rate was reduced by 50.10% after BCA approximation and increased by 6.54% after SCA approximation. Raman confocal spectroscopy revealed an increased intensity of the hydroxyapatite (HA) peak on the dentin surface after BCA application. The novel BAG-containing dentin adhesive showed the potential of both reducing dentin permeability and dentin remineralization.

Selection of adhesive systems in treatment of tooth root caries (literature review)

Adhesive dentistry is the foundation on the basis of which there have been global changes in the concept of adhesion of composite materials in therapeutic dentistry, protocols for fixing ceramic restorations in orthopedic dentistry. But a number of unsolved problems remained – the adhesion of composite materials to sclerosed dentin and tooth root cement, the sensitivity of the components of the adhesive systems to the wet environment of the oral cavity and spatial stability in the presence of dentinal fluid moving centrifugally in the dentinal tubules, the lack of restoration of periodontal attachment to the defect that occurs during tooth root caries. The review analyzes the results of studies on the use of self-etching adhesive systems in the treatment of root caries. The physician's ability to choose an adhesive system in a particular clinical case demonstrates his fundamental knowledge and minimizes the percentage of errors that he can make during the treatment phase.

Effect of 9.3 μm CO2 and 2.94 μm Er:YAG Laser vs. Bur Preparations on Marginal Adaptation in Enamel and Dentin of Mixed Class V Cavities Restored With Different Restorative Systems

This study aimed to compare marginal adaptation in enamel and dentin before and after aging of laser vs. bur-prepared mixed class V cavities restored by different restorative systems. Seventy two caries-free human molars were distributed to nine experimental groups; cavities were prepared using two different lasers: a handpiece -integrated 2.94 μm Er:YAG laser at 4.5 W, 300 mJ, and 0.75 W, 50 mJ with 15 Hz (LiteTouch, Light Instruments, Israel) and a novel CO2 laser at 12.95 W, 19.3 mJ, and 4.1 W, 6.11 mJ with 671 Hz (Solea 9.3 μm, Convergent Dental, USA). Cavities prepared with conventional diamond burs (Intensiv, Switzerland) in a red contra angle at high speed under maximal water cooling served as control. Cavities were prepared under simulation of dentinal fluid and restored using three different self-etching universal adhesives in combination with three nanohybrid composites, applied in two layers: Scotchbond Universal with Filtek Supreme XTE (3M, USA), G-Premio BOND with Essentia Universal (GC, Japan), and OptiBond Universal with Harmonize Universal (Kerr, USA). After restorations' polishing and simultaneous thermal (5–50°C, 2 min each) and mechanical loading (max. 49 N; 200,000 cycles), replicas of restoration margins were examined under SEM at × 200 magnification. Percentages of continuous margins (CMs) were quantified before and after the fatigue test and statistically compared (two-way ANOVA with Fisher's least significant difference [LSD] post hoc test). Significant differences were found in almost all groups between the results before and after the fatigue test, as well as between the different preparation tools and restorative materials (p &amp;lt; 0.05). Traditional bur preparations are confirmed as gold standard in enamel and dentin, as all three tested restorative systems provide results of marginal adaptation of more than 80% CM after loading. Er:YAG laser preparations can be equally effective in combination with SBU/Filtek Supreme XTE. CO2 laser ablation could not provide convincing results with the tested self-etching restorative systems. Marginal adaptation has been highly dependent on the substrate and showed impaired adhesion, especially in enamel. Scotchbond Universal/Filtek Supreme XTE showed the highest and most stable values of CM. The other two restorative systems were highly dependent on the preparation device of the substrate.

Method for predicting the development of cervical caries and teeth with wedge-shaped defect in young people

Annotation. Significant prevalence of cervical caries and teeth with wedge-shaped defect is the reason for the search for ways to predict their development that is possible only with an individual approach. The purpose of the study is to design and test the method for predicting the development of cervical caries and teeth with wedge-shaped defect in young people based on the results of determining the chemical composition of enamel, dentin and oral fluid. The chemical composition of the enamel and dentin of 29 teeth was examined using JSM-6490 LV focused beam electron microscope (scanning). We determined the content of the chemical elements in the oral fluid of 33 patients: Сa2+, РО43-, SO42 - by spectrophotometric method, Na+, К+, Al3+ by atomic emission spectrometry, Mg2+, Zn2+ by atomic absorption spectrometry, Cl- using chloride selective electrode of pH meter. Statistical analysis was performed using the computer program Statistica 8.0 (STA862D175437Q). Analysis of variance (Welch test), Pearson's parametric correlation method (Brave-Pearson coefficient (r)) was used. The reliability of the obtained results was evaluated by Student's t-test, the correlation between the indicators – by Student's test using the Z-test (Fisher's z-test) at p≤0.05. It was determined that the values of the К/Na+Са/Сl coefficient in enamel (equator, cervical region), dentin (cervical region), oral fluid significantly differed depending on the state of hard dental tissues (p≤0.05). Direct correlation of moderate and high strength was revealed between Са/Р and К/Na+Са/Сl – coefficients in cervical enamel and saliva (p≤0.0001). Obtained results became the basis for the development of the method for individual prediction of the development of cervical pathology in young people. Its approbation was carried out in 43 patients, its effectiveness was assessed a year later. With the values of the К/Na+Са/Сl 2 coefficient and lower we diagnosed the absence of the risk of developing cervical caries and wedge-shaped defect, from 2.1 to 5.3 the risk of developing cervical caries was diagnosed, from 5.4 and more the risk of developing wedge-shaped defect was found out. It was confirmed that the proposed method is informative (the prediction accuracy reaches 83,7%), its non-invasiveness is the basis for widespread use. We consider the search for the ways to predict particularly the development of teeth cervical pathology based on the parameters of the oral fluid and dental biofilm to be promising.

Comparative analysis of methods to stimulate and collect dentinal fluid: a clinical and experimental study

The aim - to determine the most effective method of dentinal fluid collection and dentinal fluid flow rate stimulation. In a series of dentinal fluid collection tests, 3 types of filter membranes «Technofilter» were compared to a blotting nitrocellulose membrane Sartorius 1288. An ability of the studied membranes to adsorb dentinal fluid was assessed based on the data of proton magnetic resonance using signal magnitudes of the organic molecules accumulation in dentine fluid samples. In the study 30 permanent teeth with a diagnosis of K04.00 «Initial pulpitis» were included. Teeth were randomly divided into 5 groups in accordance with the method used to stimulate the dentinal fluid flow rate. Dentinal fluid volume before and after stimulation within and between the groups was compared. The nitrocellulose membrane Sartorius 1288 has the highest ability to adsorb dentinal fluid; predominant dentinal fluid volume was obtained using a 10% dextran solution with low molecular weight. Based on the results of the study, the author proposed the method of dentinal fluid collection. The proposed stimulation method increases the dentinal fluid yields by 2 times in comparison with sampling under natural conditions.