Enhancing the inhibition of dental erosion and abrasion with quercetin-encapsulated hollow mesoporous silica nanocomposites

Introduction: Dental erosion and abrasion pose significant clinical challenges, often leading to exposed dentinal tubules and dentine demineralization. The aim of this study was to analyse the efficacy of quercetin-encapsulated hollow mesoporous silica nanocomposites (Q@HMSNs) on the prevention of dentine erosion and abrasion. Method: Q@HMSNs were synthesized, characterized, and evaluated for their biocompatibility. A total of 130 dentine specimens (2 mm × 2 mm × 2 mm) were prepared and randomly distributed into 5 treatment groups (n = 26): DW (deionized water, negative control), NaF (12.3 mg/mL sodium fluoride, positive control), Q (300 μg/mL quercetin), HMSN (5.0 mg/mL HMSNs), and Q@HMSN (5.0 mg/mL Q@HMSNs). All groups were submitted to in vitro erosive (4 cycles/d) and abrasive (2 cycles/d) challenges for 7 days. The specimens in the DW, NaF, and Q groups were immersed in the respective solutions for 2 min, while treatment was performed for 30 s in the HMSN and Q@HMSN groups. Subsequently, the specimens were subjected to additional daily erosion/abrasion cycles for another 7 days. The effects of the materials on dentinal tubule occlusion and demineralized organic matrix (DOM) preservation were examined by scanning electron microscopy (SEM). The penetration depth of rhodamine B fluorescein into the etched dentine was assessed using confocal laser scanning microscopy (CLSM). The erosive dentine loss (EDL) and release of type I collagen telopeptide (ICTP) were measured. The data were analysed by one-way analysis of variance (ANOVA) with post hoc Tukey's test (α = 0.05). Results: Q@HMSNs were successfully synthesized and showed minimal toxicity to human dental pulp stem cells (HDPSCs) and gingival fibroblasts (HGFs). Q@HMSNs effectively occluded the dentinal tubules, resulting in a thicker DOM in the Q@HMSN group. The CLSM images showed more superficial penetration in the HMSN and Q@HMSN groups than in the quercetin, NaF, and DW groups. The Q@HMSN group exhibited a significantly lower EDL and reduced ICTP levels compared to the other groups (p < 0.05). Conclusion: Q@HMSNs hold promise for inhibiting dentine erosion and abrasion by promoting tubule occlusion and DOM preservation.

Evaluating the antibacterial effect of synthesized herbal toothpastes and their efficacy for dentine tubule occlusion: Scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis

The tubule occlusion of two newly developed herbal toothpastes was examined. They were prepared based on the mixture of pomegranate peel and Equisetum arvense extracts with strontium acetate. The antimicrobial activity of pomegranate peel and E. arvense were determined using minimum inhibitory concentration (MIC). Then, 30 mid-coronal dentin discs from the human third molars were etched for 30 s with the lemon juice (pH = 2.4). The specimens divided into the three groups. While the control group had 6 specimens, Groups 1 and 2 were including 12 specimens. Group 1 brushed with toothpaste containing 10% strontium acetate and 5% hydroalcoholic extracts of pomegranate peel, and Group 2 brushed with 5% strontium acetate, 5% hydroalcoholic extracts of E. arvense, and 5% hydroalcoholic extracts of pomegranate peel. Brushing was simulated for 6 months with 2 N loading. Then, 50% of discs in each group were immersed in lemon juice for 1 min. Moreover, specimens in control group were brushed with distilled water. Finally, all 30 discs were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDXS). The occluded dentin tubules were counted and statistically evaluated. It was found that the number of open dentin tubules decreases significantly after brushing with both tested toothpastes compared with control group (p < .001). Moreover, a significant difference was observed between two toothpastes before and after acid immersion process (p < .001). The SEM micrographs confirmed the dentin tubule occlusion of both herbal dentifrices. Besides, EDXS analysis approved the strontium and silica presence on the dentin tubules for the toothpaste which was based on E. arvense.

Quantitative assessment of dentine mineralization and tubule occlusion by NovaMin and stannous fluoride using serial block face scanning electron microscopy

Dentine hypersensitivity (DH) is one of the most common dental conditions affecting most adults during their lifetime. Tubule occlusion is a widely accepted method for treating DH. Current in-vitro techniques such as focused ion beam, scanning electron microscopy (SEM), or hydraulic conductance that are used to determine tubule occlusion do not provide the depth of occlusion, are time-consuming, expensive and the volume of dentine tested is limited. The presented study aimed to assess the ability of serial block-face SEM (SBF-SEM) to section dentine, to quantify the number of occluded tubules including the depth of penetration by NovaMin and stannous fluoride (SnF₂ ) and to compare mineral density between the control and treated dentine. Results demonstrated that NovaMin provided a better occlusion with 100% of the tubules blocked at the surface compared to 83% for SnF₂ . The grayscale value (230.42) was significantly higher (p ≤ 0.05) after treatment with NovaMin compared to SnF₂ (222.06) and the control (196.37), indicating increased mineral density and dentine mineralization. SBF-SEM has the potential to be used for large volume analysis of bone-like materials at high resolution with minimal sample preparation over a short period. It can be significantly useful in the development and research of new biomaterials.

Comparing the effectiveness of four desensitizing toothpastes on dentinal tubule occlusion: A scanning electron microscope analysis

Introduction:

Dentin hypersensitivity (DH) is a sudden short sharp pain best explained by hydrodynamic theory. Several agents are available throughout the market that can treat DH either by blocking the nerves that helps in conducting pain or by blocking the open dentinal tubules. The aim of the present study was to compare the tubule occluding efficacy of four different desensitizing dentifrices under scanning electron microscope (SEM).

Materials and Methods:

Sixty-two dentin blocks measuring 5 mm × 5 mm × 3 mm were obtained from extracted human molar teeth and were randomly divided into five groups: Group 1 – no treatment (control, n = 2); Group 2 – Pepsodent Pro-sensitive relief and repair (n = 15); Group 3 – Sensodyne repair and protect (n = 15); Group 4 – Remin Pro (n = 15); Group 5 – Test toothpaste containing 15% nano-hydroxyapatite (n-HA) crystals (n = 15). The specimens were brushed for 2 min/day for 14 days and stored in artificial saliva. After final brushing, specimens were gold sputtered and viewed under SEM at ×2000 magnification. Results obtained were statistically analyzed using nonparametric Kruskal–Wallis test and least significant difference post hoc test.

Results:

All test groups showed significant increase in dentin tubule occlusion as compared to control group. The highest percentage of tubules occluded was shown by Group 4 and Group 5 which was significantly different from other groups (P ≤ 0.05), and there was no significant difference in tubule occlusion among them.

Conclusion:

Newer desensitizing dentifrices containing 15% n-HA and Remin Pro can provide effective tubule occlusion and thereby reduce the pain and discomfort caused by DH.

Evaluation of dentinal tubule occlusion and depth of penetration of nano-hydroxyapatite derived from chicken eggshell powder with and without addition of sodium fluoride: An in vitro study

Aim:

This in vitro study evaluated the degree of dentinal tubule occlusion and depth of penetration of nano-hydroxyapatite (nHAp) derived from chicken eggshell powder with and without the addition of 2% sodium fluoride (NaF) using scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM).

Materials and Methods:

nHAp was synthesized and characterized using X-ray diffraction and SEM-energy dispersive spectroscopy. Dentin discs were obtained from extracted teeth, pretreated with 17% ethylenediaminetetraacetic acid for 5 min and were divided into four groups based on the experimental agents as follows: Group 1: Untreated (control), Group 2: 2% NaF, Group 3: nHAp, Group 4: Combination of nHAp and 2% NaF. The treatment protocol was carried out for 7 days, after which the specimens were viewed under SEM and CLSM.

Statistical Analysis Used:

One-way ANOVA and Tukey's post hoc multiple comparison tests (P < 0.05).

Results:

All the experimental agents occluded the dentinal tubules, but to varying degrees and depths. Specimens treated with the combination of nHAp and 2% NaF showed complete dentinal tubular occlusion and significantly greater depth of penetration than those treated with nHAp and 2% NaF alone.

Conclusion:

The combination of nHAp and 2% NaF was the most effective in occluding dentinal tubules.