Dentin Conditioning Research Articles

Effects of using different dentin conditioners on dentin regeneration.

This experiment aimed to evaluate the impact of several dentine etching and conditioning agents on growth factors (GFs) liberation from dentine slices. Eighteen dentine slices were obtained from nine premolars divided in to six groups, the slices immersed in one mL test solutions for 5 min; Group 1: white Mineral trioxide aggregate (MTA), Group 2: Phosphate buffered saline (PBS), Group 3: 37% phosphoric acid, Group 4: 17% Ethylenediaminetetraacetic Acid (EDTA), Group 5: 10% Maleic acid (MAc), and Group 6: 0.7% Fumaric acid. The solutions were removed and stored directly at for further detection and quantification of transforming GF beta 1 (TGF-b1), bone morphogenetic protein 2 (BMP2) and vascular endothelial growth factor (VEGF) by enzyme-linked immunosorbent assay (ELISA). One-way ANOVA was used to compare the mean release and standard deviation between groups (α = 0.05). Tukey's post hoc applied for multiple comparisons. After five min conditioning of dentine slices, white MTA released the highest level of TGF-b1, BMP2 and VEGF among all groups, followed by 0.7% Fumaric acid with no significant difference between them, but compared to 37% phosphoric acid and PBS groups significant difference observed, which they released the least amount of GFs amongst all groups. Based on the results of this research the detectable release of TGF-b1, BMP2 and VEGF by 0.7% fumaric acid was comparable with white MTA from dentin slices.

Experimental and Chitosan-Infused Adhesive with Dentin Pretreated with Femtosecond Laser, Methylene Blue-Activated Low-Level Laser, and Phosphoric Acid.

Aim: To prepare experimental adhesive (EA) with 1% and without chitosan nanoparticles on dentin conditioned with a conventional technique phosphoric acid (PA) compared with two different contemporary techniques: photodynamic therapy (PDT) and femtosecond laser (FSL). Method: The methodology consisted of synthesis of EA and 1% chitosan-modified adhesive (CMA). Scanning electron microscopy, dentin adhesive interface assessment, energy-dispersive spectroscopy, shear bond strength (SBS), degree of conversion (DC), and bond failure were assessed. Teeth were selected, disinfected, and mounted in acrylic up to the cementoenamel junction. Occlusal enamel was removed and teeth were randomly allocated into groups and conditioned. These included Group 1: samples treated with PA; Group 2: specimens conditioned with methylene blue photosensitizer (MBP) activated by PDT; and Group 3: samples conditioned with FSL. Following different conditioning regimes, specimens were bonded using 1% CMA and EA. The composite buildup was followed by SBS testing and a bond failure assessment. DC was assessed for both EA and CMA. Analysis of variance and Tukey's post hoc test were used to compare the mean and standard deviation of SBS and DC in different experimental groups, with a significance level of p < 0.05. Results: Dentin pretreated with etch and rinse demonstrated the highest bond strength with 1% CMA. Dentin conditioned with MBP activated by PDT and bonded to EA showed the lowest bond scores. Overall SBS values of 1% CMA were better than EA irrespective of the conditioning regime of dentin. The DC was higher in EA adhesive. This was followed by DC in 1% CMA. DC in EA was found to be comparable with 1% CMA. Conclusions: PA remains the gold standard for dentin conditioning. The incorporation of 1% chitosan in adhesive improves SBS and results in no change in DC. The use of FSL in dentin conditioning can be used as an alternative approach as it results in SBS within acceptable limits. The study was approved by the ethical board of King Saud University.

Influence of Dentin Sealing Technique on the Shear Bond Strength between Lithium Disilicate Ceramics and Try-In-Paste-Contaminated Dentin

This study aimed to evaluate the effect of try-in paste contamination on the bond strength of lithium disilicate glass–ceramic to dentin treated with immediate (IDS) or delayed (DDS) dentin sealing techniques. Occlusal halves of 33 molars were decapitated and divided into three groups (n = 10). Lithium disilicate discs (3 × 5 mm) were prepared. For Group A, the provisional crown was applied over dentin and was soaked in distilled water. Lithium disilicate discs were cemented following dentin conditioning with a three-step etch and rinse adhesive. In Group B (IDS), the three-step adhesive was applied to dentin. The dentin surfaces were conditioned only in the final cementation for Group C (DDS). The intaglio surfaces of test groups were contaminated with try-in paste. All specimens were thermally cycled 3000 times at 5–55 °C and were subjected to shear tests. An additional three specimens for each group were contaminated with try-in paste and subjected to the same surface cleaning as the test specimens were examined with SEM/EDS. The adhesive surfaces were also examined with SEM/EDS for try-in paste remnants. Group C showed a significant decrease in bond strength values compared to Group B and Group A (5.84 ±1.4 MPa, 11.45 ±2.4 MPa, and 10.29 ±2.5 MPa, respectively). No statistically significant difference was detected between Group B and Group A (p ≥ 0.05). The SEM-EDS analyses revealed obstructions of the dentinal tubules in the try-in-paste-contaminated specimens. Immediate dentin sealing application enhanced the bonding strength of lithium disilicate to the try-in-paste-contaminated dentin. Try-in paste contamination over dentin negatively influenced the bonding process.

Effect of Alpha Hydroxy Acids as Dentin Conditioning Agents on Growth Factor Release: An In Vitro Study.

The study aimed to evaluate the effects of alpha hydroxy acids and chelating agents on dentin conditioning for the release of growth factors. The agents used for dentin conditioning included 17% ethylenediaminetetraacetic acid (EDTA), 10% glycolic acid (GA), 10% citric acid (CA), and 5% maleic acid (MA). Forty horizontally sectioned (SV1) human dentine slices were conditioned for 5 and 10 minutes so that the growth factor liberation reached quantifiable levels. Transforming growth factor beta-1 (TGF-β1) release and surface exposure were quantified by enzyme-linked immunosorbent assay (ELISA). Growth factor measurement required immediately removing the solutions from each of the 48-well plates (with consistent dentine surface area and weight) and freezing at -20°C so that ELISA measured the growth factors. After 5-min conditioning of dentine slices, CA was the most effective agent for growth factor release into the aqueous environment as measured by ELISA (post hoc Tukey's test p<0.05). Furthermore, dentine slices subjected to GA treatment for the same duration of time showed noticeably lower surface levels of TGF-β1 in comparison to the other agents employed. Based on the findings of this in vitro study, a desirable biological growth factor-mediated effect may be gained when conditioning dentin with milder acidic or chelating agents such as CA, MA, and EDTA.

Effect of the anti-Alzheimer drug GSK-3β antagonist on numerical modeling of the energy dissipation through the resin-dentin interface

ObjectivesThe aim of this study was to determine the viscoelastic performance and energy dissipation of conditioned dentin infiltrated with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs). MethodsDentin conditioned surfaces were infiltrated with NPs and TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nano-DMA/complex-loss-storage moduli-tan delta assessment and atomic force microscopy (AFM) analysis. ResultsDentin infiltrated with NPs and load cycled attained the highest complex modulus at hybrid layer and bottom of hybrid layer. Intertubular dentin treated with undoped NPs showed higher complex modulus than peritubular dentin, after load cycling, provoking energy concentration and breakdown at the interface. After infiltrating with TDg-NPs, complex modulus was similar between peri-intertubular dentin and energy dissipated homogeneously. Tan delta at intertubular dentin was higher than at peritubular dentin, after using TDg-NPs and load cycling. This generated the widest bandwidth of the collagen fibrils and bridge-like mineral structures that, as sight of energy dissipation, fastened active dentin remodeling. TDg-NPs inducted scarce mineralization after thermo-cycling, but these bridging processes limited breakdown zones at the interface. SignificanceTDg-based NPs are then proposed for effective dentin remineralization and tubular seal, from a viscoelastic approach.

CONTROL OF DENTINE HYPERSENSITIVITY WITH THE USE OF DESENSITIZING: Case report of a patient from the city of Mato Verde - MG

Dentin hypersensitivity is characterized by an exacerbated response to thermal, chemical, osmotic and tactile sensory stimuli in the area where the dentin is exposed, causing acute and short-lasting painful symptoms. This study aimed to report a clinical case of control of dentin hypersensitivity using desensitizers. A qualitative study with observational/descriptive objectives, carried out in the municipality of Mato Verde-MG at Faculdade Verde Norte (FAVENORTE).The study was approved by the Research Ethics Committee, with opinion no. 6,985,721. A 22-year-old female patient attended dental care at the FAVENORTE Dental Clinic, complaining of intense sensitivity in several teeth. A medical and dental history was collected during anamnesis, as well as information regarding routine and lifestyle. On clinical examination, gingival recession and root exposure were found in elements 14, 15, 16, 24, 25, 34, 35, 44, 45, without loss of tooth structure. In the occlusal assessment, no changes were observed. The patient reports brushing teeth more than four times a day and using excessive force when brushing. After evaluation, it was concluded that the main etiological factor of the injuries was caused by a mechanical factor. For treatment, a desensitizer based on potassium nitrate (neural action) with sodium fluoride (obliterating action), Desensibilize KF 2%, was used. In the treatment of dentin hypersensitivity in the case described, the use of desensitizer, oral hygiene instructions, associated with maintenance with the use of dentifrice, proved to be a satisfactory procedure, since at the end of the treatment, the degree of discomfort related to the hypersensitivity condition dentin previously reported by the patient, ceased to exist. Therefore, the use of desensitizing agents is a low-cost procedure with excellent results.

Do in vitro and in situ erosive challenges alter the bonding performance of universal adhesives?

ObjectiveTo evaluate microtensile bond strengths (μTBS), nanoleakage (NL), and degree of conversion (DC) of two universal adhesives, using etch-and-rinse (ER) or self-etch (SE) strategies on eroded dentin submitted to in vitro and in situ erosive challenges. MethodsDentin blocks were prepared from 120 human molars and categorized based on dentin condition (sound, in vitro eroded, and in situ eroded), adhesive system (Scotchbond Universal [SBU] and Zip bond Universal [ZIP]), and adhesive strategy (ER and SE). In the in situ erosive challenge, 20 volunteers wore acrylic resin palatal devices with dentin blocks, immersing them in cola soft drink for 90 s, six times daily for 15 days. The same erosive protocol was used in vitro, followed by rinsing and remineralization. Sound dentin blocks served as controls. Afterward, all dentin blocks were restored with composite resin and sectioned into resin-dentin bonded sticks for μTBS, NL, and DC assessments. Data were analyzed using three-way ANOVA and Tukey's test (α = 0.05). ResultsSound dentin exhibited the highest μTBS and DC values and the lowest NL values, while in situ eroded dentin showed the lowest μTBS and DC values and the highest NL values (p = 0.000001). While some differences in the μTBS values were observed between universal adhesives when evaluated on sound dentin (p = 0.0001), no significant differences between adhesives were observed when tested on in vitro and in situ eroded dentin. Regarding NL and DC, no significant differences were found between SBU and ZIP, as well as among adhesive strategies (p > 0.05). ConclusionErosion in dentin, especially under in situ conditions, presents significant challenges to the adhesion of restorative materials. The choice of an effective adhesive system is crucial, as dentin eroded in situ showed lower adhesion strength and greater nanoleakage. These results highlight the need for specific clinical strategies to improve the durability and effectiveness of restorations.

Effect of inositol hexaphosphate acid versus polyacrylic acid on dentin properties and adhesion of a self-adhesive restorative material to dentin

ObjectiveThis study evaluated the effect of 2% inositol hexaphosphate (IP6) and 10% polyacrylic acid (PAA) on dentin surface micromorphology, matrix/mineral ratio, microhardness, and resin−dentin shear bond strength (SBS) of a self-adhesive restorative material (Surefil™ One; Dentsply Sirona, Konstanz, Germany). Materials and methodsHuman permanent molar mid-coronal dentin discs were either not treated (control), conditioned with 10% PAA (Dentin Conditioner, GC, Tokyo, Japan) for 20 s, or etched with 2% IP6 for 20 s. Dentin surface micromorphology (etching pattern), matrix/mineral ratio, and microhardness were characterized by a scanning electron microscope (SEM), a confocal Raman microscope and a microhardness tester using the Vickers indenter, respectively. Sound molars were cut flat, mounted, surface treated and restored with Surefil™ One, Dentsply. The shear bond strength (SBS) was evaluated using a universal testing machine at 24 h and after 10k thermo-cycles. The failure modes were assessed. One-way and two-way analysis of variance (ANOVA) followed by the Tukey's multiple comparisons test was used for the statistical analysis. ResultsIP6 etching resulted in a more aggressive and uniform etching pattern compared with PAA. The mineral/matrix and Vickers microhardness of IP6-etched dentin were significantly less than those of PAA-conditioned dentin. IP6 etching significantly improved the resin−dentin SBS compared with the control group (no treatment) at 24 h and after thermo-cycling. Adhesive failures were the most predominant in all study groups. ConclusionInositol hexaphosphate acid etching deteriorated dentin microhardness and resulted in substantial demineralization, however, it eliminated the dentin smear layer completely and created marked micromorphological alteration at dentin surface, significantly increasing the resin−dentin SBS of a self-adhesive restorative material.

Ultrasonic activation of adhesive systems increases bond strength and intratubular penetration of resin cement in root dentin subjected to radiation therapy.

This study aimed to evaluate the effect of ultrasonic activation of etch-and-rinse and self-etch adhesive systems on the bond strength of resin cement to irradiated root dentin. Eighty human maxillary anterior teeth were distributed into 8 groups (n = 10), according to the type of adhesive system used (etch-and-rinse and self-etch), the ultrasonic activation of the adhesive systems, and the dentin condition (irradiated or non-irradiated - 70Gy). Endodontic treatment was performed followed by fiberglass post-space preparation. After fiberglass posts' luting, the roots were transversely sectioned on dentin discs and submitted to the push-out bond strength test (0.5mm/min). The fractured specimens were analyzed under a stereomicroscope and Scanning Electron Microscope (SEM) for failure mode classification. One of the dentin discs was analyzed under SEM to evaluate the characteristics of the adhesive interface. Irradiated specimens had lower bond strength than non-irradiated specimens (P < 0.0001). Ultrasonic activation of both adhesive systems increased the bond strength of the resin cement to irradiated dentin (P < 0.0001). Radiotherapy significantly affected the failure mode in the middle (P = 0.024) and apical thirds (P = 0.032) (adhesive failure). Non-irradiated specimens had a more homogeneous adhesive interface. When ultrasonically activated, both adhesive systems showed a greater number of resinous tags, regardless of the dentin condition. Ultrasonic activation of adhesive systems is a feasible strategy to enhance fiberglass posts retention in oncological patients.

Assessment of the Micro-Tensile Bond Strength of a Novel Bioactive Dental Restorative Material (Surefil One).

The aim of this study is to assess the micro-tensile bond strength and the mode of failure of a bioactive hybrid self-adhesive composite (Surefil one) under various dentin conditions. Thirty-two extracted human molar teeth were used to test the micro-tensile bond strength of Surefil one under different dentine conditions (no treatment, 37% phosphoric acid etching, and universal adhesive) in comparison with a resin-modified glass ionomer (RIVA). All restorations were light cure-bonded onto flat dentine and then sectioned into beams. Then, fractured specimens were observed under a light microscope to evaluate the mode of failure. The Surefil one no-treatment group (NTG) exhibited the highest micro-tensile bond strength. Furthermore, there was no statistically significant difference observed between the Surefil one adhesive group (EAG) and the Surefil one acid etch group (EG). However, compared to other groups, the resin-modified glass ionomer (RIVA) produced the lowest results, which are statistically significant. Surefil one offers superior bond strength values when compared to resin-modified glass ionomers. Furthermore, Surefil one requires no dentin condition and has more straightforward clinical steps.

Extrafibrillar demineralization: Yes or no?

ObjectiveExtrafibrillar demineralization is considered to be an ideal solution for addressing the durability of resin-dentin bonding interfaces. However, its theoretical basis is contradictory to ionization equilibrium of hydroxyapatite dissolution. In this study, various calcium chelators were selected as dentin conditioners to explore the essence of dentin demineralization with chelators and its effect on resin-dentin adhesion. MethodsPolyethyleneimine grafted with EDTA and polyacrylic acid sodium (PAAN450k) larger than 40 kDa, as well as PAAN (PAAN3k) and EDTA smaller than 6 kDa, were prepared as dentin conditioners. The dentin powder was designed to characterize whether it would demineralize without contact with PAAN450k. Dentin demineralization effect with four conditioners was evaluated with field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, atomic force microscopy and quantification of hydroxyproline concentration after enzymatic degradation. Micro-tensile bond strength (µTBS) test and failure mode analysis were employed to assess the bonding effect of the four chelators in both wet and dry bonding, with H3PO4 wet bonding serving as the control group. ResultsDemineralization occurs when PAAN450k was not in direct contact with the dentin powder. The extrafibrillar demineralization cannot be induced by any chelator regardless of its molecular weight. Complete demineralization including extrafibrillar and intrafibrillar demineralization would occur with sufficient interaction time. Moreover, chelators could not provide a reliable dentin bonding effect under a short interaction time. SignificanceFrom the perspective of theory and application, extrafibrillar demineralization is not a reliable strategy, which provides a reminder for exploring new strategies in the future.

Impact of using XP-endo finisher and nanobubble water during EDTA dentin conditioning on TGF-β1 release in regenerative endodontic procedures.

Transforming Growth Factor-Beta 1 (TGF-β1) plays a crucial role in the success of Regenerative Endodontic Procedures (REPs) as they directly impact the proliferation and differentiation of stem cells. TGF-β1 is released by conditioning of the dentin matrix using 17% EDTA. EDTA was found to have deleterious effects on dentin especially in immature teeth with fragile dentin walls. Decreasing the irrigation time was reported to decrease these effects. Accordingly, enhancement and activation of the EDTA solution to maintain its efficiency in TGF-β1 release from dentin and thus compensating the reduction in irrigation time was employed. EDTA solution was enhanced by adding Nanobubble (NB) water which contains oxygen filled cavities less than 200nm in diameter. Additionally, EDTA was activated with XP-endo Finisher rotary file. The aim of this study was to assess the impact of NB enhancement and/or XP-endo Finisher activation of the EDTA solution on the TGF-β1 release from dentin. Fifty standardized root segments with open apex were allocated to two main groups according to whether EDTA was enhanced with NB water or not, and within each group whether XP-endo Finisher activation was used or not in addition to a Negative Control group. The concentration of the released TGF-β1 in the root canal was measured using enzyme-linked immunosorbent assay (ELISA). The statistical analysis was done using the Shapiro- Wilk, Kolmogorov Smirnov, ANOVA and Post-hoc Tukey tests. All groups released a considerable amount of TGF-β1 with the highest values in the EDTA/NB/XP group, followed by EDTA/NB, EDTA/DW/XP, EDTA/DW and Negative Control groups respectively. The results of this study suggest that NBs can promote the success of REPs since it revealed a significant increase in the TGF-β1 release following its use in the enhancement of the EDTA solution. A comparable effect was obtained by XP-endo finisher activation of the EDTA solution. The combined use of NBs and XP-endo Finisher can be a promising addition in REPs. Accordingly, Enhancement and activation of the EDTA solution may compensate decreasing the EDTA irrigation time attempted to avoid the deleterious effect of EDTA on dentin.

Tunable polymer-peptide hybrids for dentin tissue repair

ObjectivesThis study targets to assess the remineralization capability of conditioned dentin infiltrated with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs). MethodsDentin conditioned surfaces were infiltrated with NPs and TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nanohardness, Masson's trichrome staining microscopy, and Raman analysis. ResultsDentin surfaces treated with TDg-NPs and load cycled produced higher nanohardness than the rest of the groups at the hybrid layer. At the bottom of the hybrid layer, all samples treated with TDg-NPs showed higher nanohardness than the rest of the groups. Active remineralization underneath the hybrid layer was detected in all groups after TDg application and load cycling, inducting new dentinal tubuli formation. After thermocycling, remineralization at the hybrid layer was not evidenced in the absence of NPs. Raman analysis showed increase mineralization, enriched carbonate apatite formation, and improved crosslinking and scaffolding of the collagen. ConclusionsMechanical loading on the specimens obtained after TDg-NPs dentin infiltration inducts an increase of mineralization at the resin/dentin interface, indicating remineralization of peritubular and intertubular dentin with augmented crystallographic maturity in crystals. Enriched collagen quality was produced, generating an adequate matrix organization to promote apatite nucleation, after tideglusib infiltration. Clinical significanceAt the present research, it has been proved the creation of reparative dentin, at the resin-dentin interface, after tideglusib dentin infiltration. Chemical stability, to favor integrity of the resin-dentin interface, is warranted in the presence of the TDg-NPs in the demineralized dentin collagen.

In Vitro Effects of Chlorhexidine and Isopropyl Alcohol Conditioning Agents on Immediate and Late Bond Strength of Fiber Posts Dentin.

Objectives: This study assessed the effect of chlorhexidine (CHX) and isopropyl alcohol (IA) on immediate and late pushout bond strength (PBS) of fiber posts to dentin. Materials and Methods: In this in vitro study, 54 single-canal premolars were endodontically treated, and randomly assigned to 3 groups (N=18) for root dentin conditioning with distilled water (control), 2% CHX, and 70% IA after post space preparation. Fiber posts were cemented with TheraCem self-adhesive cement, and each group was subdivided into two subgroups (N=9) for PBS measurement immediately after bonding, and after 5000 thermal cycles (5-55°C). The roots were then sectioned, and their PBS was measured. The mode of failure was evaluated under a stereomicroscope at ×40 magnification. Data were analyzed by repeated measures ANOVA and Tukey's test (alpha=0.05). Results: The highest PBS was noted in the IA group (21.12 MPa) after 24 hours and the lowest PBS belonged to the control group after thermocycling (7.48 MPa). The immediate and post-thermocycling PBS were significantly lower in the control group than the CHX group (P<0.05). The PBS in both the control and CHX groups was lower than that in the IA group (P<0.001). Regardless of the type of detergent, a significant reduction in PBS was observed after thermocycling (P<0.003). The PBS significantly decreased from the cervical towards the apical region in all groups (P<0.001). Conclusion: According to the results, application of IA before the self-adhesive cement effectively improved the immediate and late PBS, and was significantly more effective than CHX.

Bond strength comparison of a fiber-reinforced composite resin: Different dentin conditions and preparation techniques.

This study aimed to compare the bond strength of a fiber-reinforced composite resin with traditional and bulk-fill composite resins under different dentin conditions and preparation techniques. Eighty molar teeth, excluding the mesio-distal half of the occlusal dentin surfaces of each teeth, were isolated with acid-resistant nail varnish and stored in a demineralisation solution (pH 4.5). After mechanical removal of the varnish, the teeth were buried in acrylic resin blocks. In every composite resin group, one-half of the specimens were prepared with a diamond bur and another half with Er: YAG laser. Then, the specimens were divided into four groups of composite resins (Filtek Z250, G-aenial Posterior, SonicFill 2, Ever X Posterior) (n = 10). Shear bond strengths were measured using a universal testing device, and failure types were determined with stereomicroscope images. SEM images were obtained at 1000× magnification. Data were analyzed using a three-way analysis of variance (ANOVA), and Bonferroni correction was used for multiple comparisons (p = .05). Differences in the dentin surface affected the bond strength results (p < .05), whereas there was no significant difference between cavity preparation methods (p > .05). EverX Posterior showed the highest bond strength results. Within the limitations of this study, fiber-reinforced composite resin exhibited successful bond strength results in addition to improved mechanical properties. RESEARCH HIGHLIGHTS: Fiber-reinforced composite had successful bond strength values. Bond strength values of sound dentin groups were higher than those of caries-affected dentin groups. The use of an Er: YAG laser for preparation did not lead to insufficient bond strength results.

Effect of ethanolic extract of propolis on antibacterial and microshear bond strength of glass-ionomer restorations to dentin

ObjectivesThis study was conducted to evaluate the effect of ethanolic extract of propolis on antibacterial and microshear bond strength of glass ionomer restorations to dentin. Materials and methodsConventional glass ionomer cement (Equia forte, GC Tokyo, Japan), resin-modified glass ionomer (Fuji II LC, GC Tokyo, Japan) and propolis powder (dried extract from honey bees) materials were used in this study. Both conventional glass ionomer and resin-modified glass ionomer were modified by two different concentrations of ethanolic extract of propolis (10 % and 25 % EEP). For antibacterial test, Streptococcus mutans strain was spread on agar petri dishes using a sterile swab. Discs of both glass ionomer restorative materials (without adding EEP, with 10 % EEP and with 25 % EEP) were fabricated within the agar plates. Antibacterial activity was evaluated by measuring the inhibition zones around each disc. For microshear bond strength test, 60 healthy human permanent molars were prepared by cutting occlusal surface and expose the dentin at the height of contour of all teeth then conditioned using poly acrylic acid conditioner, both glass ionomer restorative materials (without adding EEP, with 10 % EEP and with 25 % EEP) were mixed and applied on conditioned dentin surface by using tygon tube. Microshear bond strength was evaluated by the universal testing machine. ResultsTwo-way ANOVA test revealed that both glass ionomer type and different concentrations of EEP had significant effect on the antibacterial test results and microshear bond strength values (p < 0,05). Glass ionomer restorative material with 25%EEP had the highest antibacterial values whereas glass ionomer restorative material without modifications (control groups) had the lowest values. Resin-modified glass ionomer without any modification (control group) had the highest bond strength while resin-modified glass ionomer with 25%EEP had the lowest bond strength. ConclusionsIncorporation of ethanolic extract of propolis to glass ionomer restorative material increases the antibacterial effects of both conventional GIC and RMGI. Inspite of this advantage, it seems that it has deleterious effect on microshear bond strength to dentin.

MICROTENSILE BOND STRENGTH OF UNIVERSAL ADHESIVE TO DENTIN AFTER ER: YAG LASER PRETREATMENT WITH DIFFERENT CONDITIONING MODES - AN IN VITRO STUDY

Adhesion to dentin remains challenging due to its complex nature that prevents complete infiltration of hydrophobic monomer to hydrophilic dentinal substrate. Recently, Er:YAG laser has been used in dentin pretreatment to enhance the bond strength. A deficient hybrid layer is formed following laser etching as it causes thermal damage and collagen denaturation of dentinal substrate. As the results are controversial, attempts are made to modify laser etching technique with respect to energy density, pulse duration and water spray. Thus, the present study aimed to evaluate the influence of Er:YAG laser conditioning of dentin by activation of Chlorhexidine collagen stabilising agent on the bond strength. Samples included 60 freshly extracted premolar which were divided into three groups (n=20) based on the protocol of dentin pretreatment done: Group 1 (Control) - Phosphoric acid etching followed by universal adhesive; Group 2 (Experimental) - Conventional Er:YAG laser dentioning; Group3 (Experimental) - Er:YAG laser dentin conditioning with coronal reservoir of 0.12% Chlorhexidine. Occlusal class 1 cavity was prepared on the samples followed by which dentin conditioning protocol was carried out for the respective groups. Universal adhesive was applied followed by Composite resin restoration. 1000 cycles of Thermocycling was done and the samples were sectioned to obtain microsections. Microtensile bond strength values were obtained by subjecting the specimens to Universal testing machine.Highest microtensile bond strength value was obtained for group 1 followed by group 3 with least value obtained for Group2 with statistically significant values between the groups. (p&lt;0.0001). Within the limitations of the present invitro study, it can be concluded that preetching with phosphoric acid increases the bond strength of universal adhesive to dentin. Laser conditioning of dentin through activation of chlorhexidine provided better bond strength value of universal adhesive when compared to conventional laser dentin conditioning.

The effect of roselle (Hibiscus sabdariffa l.) flower petal extract on smear layer removal of crown dentin

One of the initial stages carried out before making a restoration is the tooth preparation. The debris resulting from the preparation process of the tooth structure is called the smear layer. Dentin conditioner is needed to remove the smear layer so that the crown dentin surface is clean and the restoration can adhere well. Roselle (Hibiscus sabdariffa L.) are a herbal ingredient that has acidic properties found in its flower petals. This research was conducted to determine the effect of roselle flower petal extract on the removal of the smear layer on crown dentin. Eight human maxillary first premolars from orthodontic extraction patients were used as samples. This pre-experimental study was conducted with a test group consisted of control group conditioned with sterile distilled water and treatment group with 2,5%, 5%, and 10% of roselle flower petal extract. The research data was obtained through observing the results of scanning Electron Microscope (SEM). Roselle flower petal extracts 5% and 10% were able to clean the smear layer better than extracts with a concentration of 2.5% and the control group. This may be due to the acidic pH of the solution and demineralization process caused by the presence of citric acid and other organic acids in roselle flower petal extract.

Effect of ER: YAG Laser Treatment on the Bond Strength of Self-adhesive Resin Cements on Contaminated and Non-contaminated Dentin Surface

Background: Nowadays, lasers are used to modify the surface of dentin and enamel and improve the surface bond with resin cement while contamination weakens this bond. Objective: This study aimed to evaluate the effect of different contamination types on the microshear bond strength (μSBS) of two self-adhesive resin cements to dentin with/without laser treatment. Methods: One-hundred and twenty molar teeth were prepared and randomly divided into three groups: blood, saliva, and control. In the blood group, blood was applied to the samples for 10 seconds; in the saliva group, saliva was applied to the samples for 10 seconds; and in the control group, distilled water was applied to the samples. Each group was further divided into two subgroups; in one, the Er: YAG laser was applied to samples for 5 seconds, and in the other, no laser treatment was performed. Next, TheraCem and Embrace WetBond cements were placed on each sample. μSBS was measured using a universal testing machine. Results: In Embrace WetBond, μSBS was not affected by contamination type regardless of laser treatment. In TheraCem, μSBS was not affected by contamination type when the laser was not used. In contrast, with laser treatment, blood contamination decreased μSBS compared to control and saliva. After laser treatment in the presence of blood, μSBS of Embrace WetBond was significantly higher than that of TheraCem, while without laser treatment, no significant difference was observed between the two cements. Conclusion: Dentin conditioning with an erbium laser can increase the cement bond strength to dentin if proper isolation is achievable. If proper isolation cannot be obtained, dentin conditioning with erbium laser followed by application of Embrace WetBond cement can increase the microshear bond strength of cement to dentin.

Effect of ER: YAG Laser Treatment on the Bond Strength of Self-adhesive Resin Cements on Contaminated and Non-contaminated Dentin Surface

Background: Nowadays, lasers are used to modify the surface of dentin and enamel and improve the surface bond with resin cement while contamination weakens this bond. Objective: This study aimed to evaluate the effect of different contamination types on the microshear bond strength (μSBS) of two self-adhesive resin cements to dentin with/without laser treatment. Methods: One-hundred and twenty molar teeth were prepared and randomly divided into three groups: blood, saliva, and control. In the blood group, blood was applied to the samples for 10 seconds; in the saliva group, saliva was applied to the samples for 10 seconds; and in the control group, distilled water was applied to the samples. Each group was further divided into two subgroups; in one, the Er: YAG laser was applied to samples for 5 seconds, and in the other, no laser treatment was performed. Next, TheraCem and Embrace WetBond cements were placed on each sample. μSBS was measured using a universal testing machine. Results: In Embrace WetBond, μSBS was not affected by contamination type regardless of laser treatment. In TheraCem, μSBS was not affected by contamination type when the laser was not used. In contrast, with laser treatment, blood contamination decreased μSBS compared to control and saliva. After laser treatment in the presence of blood, μSBS of Embrace WetBond was significantly higher than that of TheraCem, while without laser treatment, no significant difference was observed between the two cements. Conclusion: Dentin conditioning with an erbium laser can increase the cement bond strength to dentin if proper isolation is achievable. If proper isolation cannot be obtained, dentin conditioning with erbium laser followed by application of Embrace WetBond cement can increase the microshear bond strength of cement to dentin.