In Vitro Evaluation of Remineralization Potential of Five Toothpastes on Soft Drink-Eroded Human Enamel and Dentine.

OBJECTIVE: The purpose of this in vitro study was to evaluate the potential remineralization of enamel and dentine erosion lesions after the application of five different toothpastes. METHODOLOGY: A total of 104 enamel and dentine samples were prepared from maxillary third molars. Each group was divided according to the toothpaste application mode (topical = 56; brushing = 48) and the toothpaste used seven topical groups and six brushing groups (n = 8). The groups included negative control (NC), positive control (PC), Sensodyne Pronamel (SP), Regenerate (R), Regenerate with boosting serum (R+), Colgate Duraphat 5000 (CD), and tooth mousse (TM). RESULTS: The statistical analysis showed significant surface microhardness (SMH) change. All enamel groups showed a significant decrease in SMH compared to NC for both application modes. However, no significance was recorded between test groups. Similar results were observed between dentine groups and their relevant controls for both application modes, except brushed R and R+ groups, which were insignificant to their NC. For topical groups, TM showed a significant increase in SMH. While R and R+ showed lower loss than SP and CD. CONCLUSIONS: All tested agents offered a degree of remineralization in both enamel and dentine with no significant difference between agents in enamel groups while R, R+, and TM offered better results in dentine groups. CLINICAL SIGNIFICANCE:  For dentine groups, similar findings were observed with superior tooth surface protection with the application of TM over other agents. Tooth surface remineralization was achieved when agents were either applied topically or brushed over the surface.

Application of Laser Treatment in Adhesive Bonding of Liners to Polymethyl Methacrylate Denture Resins: A Systematic Review and Meta-Analysis.

Objective: This systematic review and meta-analysis aimed to assess the influence of laser treatment on adhesive bonding of liners to polymethyl methacrylate (PMMA) denture base resins. Methods: The focused question was: "Does the application of laser treatment (Intervention) influence the adhesive bonding strength (Outcome) of liners to PMMA denture base resins (Population) as compared with untreated or unconditioned surfaces (Control)?" In vitro and clinical reports as well as reports on influence of laser treatments on bonding strength of liners to PMMA denture resins in comparison with untreated surfaces were included. Reports without any control group[s], without any application of laser[s] for PMMA denture bases that did not utilize PMMA denture bases, and not evaluate bond strength of PMMA denture base resins were excluded. An electronic search was conducted on PubMed, Scopus, and Web of Science. Meta-analyses were performed for calculating the standard mean difference (SMD) with a 95% confidence interval (95% CI). Results: Nine of the 12 included studies found that laser irradiation treatment produced significant surface texture alterations of the PMMA denture base and improved the adhesion between the PMMA denture base and soft lining. According to the meta-analysis, tensile bond strength showed an SMD of -2.49% (95% CI: -3.89 to -1.08; p = 0.0005), suggesting a statistically significant difference between the control and test groups (i.e., favoring laser-treated samples than untreated samples). Regarding shear bond strength scores, the outcomes showed an SMD of -2.24% (95% CI: -3.79 to -0.69; p = 0.005), suggesting a statistically significant difference between the control and test groups (i.e., favoring laser-treated samples than untreated samples). Conclusions: Despite the high heterogeneity among the included studies, it can be concluded that laser treatment might improve the bonding strengths of liners to PMMA denture base resins as compared with untreated surfaces. To validate the aforementioned conclusions, further verification is required through the implementation of well-designed randomized controlled trials with large sample sizes.

Adhesive Bond Integrity of Experimental Zinc Oxide Nanoparticles Incorporated Dentin Adhesive: An SEM, EDX, µTBS, and Rheometric Analysis.

Objective: Our study is aimed at preparing an experimental adhesive (EA) and assessing the influence of adding 5-10 wt.% concentrations of zinc oxide (ZnO) nanoparticles on the adhesive's mechanical properties. Methods: Field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy were employed to investigate the morphology and elemental distribution of the filler nanoparticles. To examine the adhesive properties, microtensile bond strength (µTBS) testing, an investigation of the rheological properties, degree of conversion (DC), and analysis of the interface between the adhesive and dentin were carried out. Results: The SEM micrographs of ZnO nanoparticles demonstrated spherical agglomerates. The EDX plotting confirmed the incidence of Zn and oxygen (O) in the ZnO nanoparticles. The highest µTBS was observed for nonthermocycled (NTC) 5 wt.% ZnO group (32.11 ± 3.60 MPa), followed by the NTC-10 wt.% ZnO group (30.04 ± 3.24 MPa). Most of the failures observed were adhesive in nature. A gradual reduction in the viscosity was observed at higher angular frequencies, and the addition of 5 and 10 wt.% ZnO to the composition of the EA lowered its viscosity. The 5 wt.% ZnO group demonstrated suitable dentin interaction by showing the formation of resin tags, while for the 10 wt.% ZnO group, compromised resin tag formation was detected. DC was significantly higher in the 0% ZnO (EA) group. Conclusion: The reinforcement of the EA with 5 and 10 wt.% concentrations of ZnO nanoparticles produced an improvement in the adhesive's µTBS. However, a reduced viscosity was observed for both nanoparticle-reinforced adhesives, and a negotiated dentin interaction was seen for 10 wt.% ZnO adhesive group. Further research exploring the influence of more filler concentrations on diverse adhesive properties is recommended.

The Effect of Dentifrice on Micro-Hardness, Surface Gloss, and Micro-Roughness of Nano Filled Conventional and Bulk-Fill Polymer Composite-A Micro Indentation and Profilometric Study.

The aim of the present study was to evaluate the effect of brushing with two whitening dentifrices (Colgate Optic White (COW) and Colgate Optic White Charcoal (COC)) on surface gloss, micro-roughness, and micro-hardness of nanostructured hybrid conventional (Z350) and bulk-fill (Tetric N Ceram bulk-fill) polymer composite. In total, 96 disk samples using two nano-hybrid composite polymers (Z350 and Tetric N Ceram Bulk-fill) were prepared. All specimens were exposed to two different dentifrices (COW and COC), resulting in four main subgroups in the study. Specimens were assessed for surface gloss, micro-roughness (Ra), and micro-hardness using standardized methodology. Means and standard deviations of properties compared using paired t-test, one-way and two-way ANOVA, and post hoc test. The presence of dentifrices did not show any significant difference in micro-hardness values of Z350 (p > 0.05), whereas micro-hardness of bulk-fill composite significantly reduced on dentifrices exposure (p ≤ 0.05). Bulk-fill polymer composite showed significant reduction in gloss after dentifrice exposure (p < 0.05), however, Z350 showed no significant loss of gloss due to dentifrices (p > 0.05). A significant increase in Ra was observed for both resin materials after exposure to dentifrices (COC and COW). Conventional resin composite (Z350) showed comparable surface hardness and gloss before and after dentifrice exposure, however, micro-roughness increased significantly due to dentifrice exposure. Bulk-fill resin (Tetric N Ceram) showed significant loss of micro-hardness and gloss and increase in micro-roughness on dentifrice exposure. Conventional nano-hybrid composite polymer showed better durability in resisting loss of surface properties compared to bulk-fill resin polymer in the present experiment.

Influence of Concentration Levels of ß-Tricalcium Phosphate on the Physical Properties of a Dental Adhesive.

Our study assessed the influence of integrating 5% and 10% tricalcium phosphate (ß-TCP-Ca3(PO4)2.) nanoparticles into a dental adhesive on the adhesive's bonding. To evaluate the filler nanoparticles, scanning electron microscopy (SEM), Energy Dispersive X-Ray (EDX) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and micro-Raman spectroscopy techniques were used. Shear Bond strength (SBS) testing, degree of conversion (DC) analysis, investigation of the adhesive-dentin interface, and biofilm experiments were conducted. The SEM micrographs revealed non-uniform agglomerates, while the EDX demonstrated the existence of oxygen 'O' (24.2%), phosphorus 'P' (17.4%) and calcium 'Ca' (60.1%) in the ß-TCP nanoparticles. The FTIR and micro-Raman spectra indicated characteristic bands for ß-TCP containing materials. The 10 wt.% ß-TCP adhesive presented the highest SBS values (NTC-10 wt.% ß-TCP: 33.55 ± 3.73 MPa, TC-10 wt.% ß-TCP: 30.50 ± 3.25 MPa), followed by the 5 wt.% ß-TCP adhesive (NTC-5 wt.% ß-TCP: 32.37 ± 3.10 MPa, TC-5 wt.% ß-TCP: 27.75 ± 3.15 MPa). Most of the detected failures after bond strength testing were adhesive in nature. The ß-TCP adhesives demonstrated suitable dentin interaction by forming a hybrid layer (with few or no gaps) and resin tags. The ß-TCP adhesives (10 wt.%) revealed lower DC values compared to control. The incorporation of 5 and 10 wt.% concentrations of ß-TCP particles resulted in an increase in SBS values. A linear decline in DC values was witnessed when the nanoparticle concentration was increased. Further research focusing on exploring the influence of higher filler concentrations on adhesive's properties is recommended.

Influence of Conventional Polymer, Hybrid Polymer and Zinc Phosphate Luting Agents on the Bond Strength of Customized Zirconia Post in Premolars-An In-Vitro Evaluation.

The aim was to identify the influence of conventional polymeric resin based cement (RC), hybrid polymer modified glass ionomer (RMGIC) and Zinc phosphate cement (ZPC) on the pull out strength of the customized zirconia post in premolars. Access cavity and root canals were performed in sixty premolar teeth with the standardized crown down technique (ProTaper Universal, Dentsply). Post space impressions were scanned, and the pre-sintered Zenostar Zr Translucent blanks (Weiland Dental, Pforzheim) were milled with the Opera-system to form the post. All prepared specimens were divided equally in three groups based on the cement type employed for luting as follows: group A: ZPC; group B (GC Fuji PLUS Capsule): RMGIC; group C (and RC (3M RelyX ARC). Ten specimens in each group were thermocycled (TC) at 5 and 55 °C in distilled water baths (40,000 cycles). Pull out bond strength was assessed using a universal testing machine at 0.5 mm/min. The means and standard deviations were compared using ANOVA and Tukey Kramer multiple comparisons tests. A significant difference among the cement groups as well as between TC and non-thermocycled (NTC) groups (p < 0.05) was observed. The highest tensile stress was demonstrated among group C (Resin, 69.89 ± 4.81 (NTC), 64.06 ± 4.36 (TC)) with the least in group A, (zinc phosphate, 43.66 ± 5.02 (NTC), 37.70 ± 5.10 (TC)) for both groups. Group A presented with 100% adhesive bond failures, followed by 80% in group C and 70% in group B, respectively. A similar outcome was observed in the TC group for the cement; however, unlike the NTC group, the TC group showed more cohesive failures compared to the NTC mixed failure. Dual cure polymer based cement demonstrated higher bond strength and efficient adhesive bonding of the customized Zr post with root dentine compared to zinc phosphate (non-polymeric) and RMGIC (hybrid polymer). Thermocycling compromised Zr post adhesive bonding to root dentin.

Shear bond characteristics and surface roughness of poly-ether-ether-ketone treated with contemporary surface treatment regimes bonded to composite resin.

AIM: To evaluate and compare the influence of contemporary surface treatments of air abrasions, sulfuric acid, and Photodynamic therapy (PDT) on the adhesive bonding and surface roughness of Poly-ether-ether-ketone (PEEK) bonded to resin composite. MATERIAL AND METHODS: One hundred and fifty PEEK (disk-shaped) specimens of 10 mm diameter and 2 mm thickness were prepared. Specimens were subjected to the following surface treatments, Control (no treatment), PDT, air abrasion using Alumina particles (110 µm) (AA-AP), Sulfuric acid (SA), and air abrasion using diamond particles (10-20 µm) AA-DP. Surface roughness (Ra) of treated samples were evaluated using surface profilometer. Universal testing machine was used to evaluate shear bond strength after composite resin build-up. Stereomicroscope was utilized for failure analysis of de-bonded samples of all five groups. Statistical analysis was performed utilizing one-way analysis of variance (ANOVA) to measure means and standard deviations of SBS among studied groups and the means of SBS were paralleled by Tukey multiple comparison tests (p > 0.05). RESULTS: The highest SBS was observed by 98% SA (19.25 ± 0.68 MPa). While specimen treated with PDT (11.69 ± 0.12 MPa) showed the lowest SBS. PEEK surface, treated with PDT and AA-DP demonstrated comparable SBS (p > 0.05). PEEK when pretreated with 98% SA (2.658 ± 0.658 µm) exhibited a significantly higher Ra value as compared to other surface-treated groups (p < 0.05). CONCLUSION: PEEK surface treated with SA showed the highest SBS and surface roughness compared to other groups. Surface roughness of PEEK treated with PDT, AA-AP, and AA-DP demonstrated no difference in Ra. PEEK surface treatment technique should be further investigated to develop reliable adhesive resin bonding.

Modified photoactivated methylene blue-incorporated quartz particles for dentin disinfection: A scanning electron microscope and spectroscopic analysis.

The aim of this study was to synthesize methylene blue-incorporated quartz particles (MB@QP) and to investigate its anti-bactericidal properties. Methylene blue was incorporated inside QP and characterized for morphology and chemical structure using scanning electron microscope (SEM) and Fourier transformed infrared spectroscopy (FTIR). Specimens were randomly divided into experimental and control groups (n = 9/groups). The dentin specimen infected with Enterococcus faecalis was treated using different treatment modalities: Control groups: treatment with 5.25% of sodium hypochlorite (NaOCl) for 60 s; MB: treatment with 1 ml MB solution and incubated for 60 s; MB-PDT (photodynamic therapy): treatment with 1 ml MB solution followed by irradiation using diode laser for 60 s; MB-QP-PDT: specimens treated with MB@QP and irradiated by the diode laser for 60s, and Er,Cr:YSGG laser alone. MB@PDT therapy showed the highest efficacy in reducing the survival rate of E. faecalis (0.49%) in comparison to control NaOCl (0.78%) and Er,Cr:YSGG laser treatment (2.17%). Encapsulating MB into QP followed by the PDT significantly improved the bactericidal capacity and significantly reduced the bacterial survival rate to 0.11% (p < .05) compared to other groups. The combination of MB incorporated into QP and PDT could be an alternative treatment modality to conventional disinfection method for eliminating bacteria from the tooth dentin. RESEARCH HIGHLIGHTS: Quartz particles are potent in delivering the photosensitizer. Photoactivated MB@QP has a higher efficacy in eliminating bacteria from tooth dentin.