Dentin Tubule Occlusion Potential of Novel Dentifrices Having Fluoride Containing Bioactive Glass and Zinc Oxide Nanoparticles

Effect of a 1.1% NaF toothpaste containing Sr/F-doped bioactive glass on irradiated demineralized dentin: an in vitro study

OBJECTIVE

Patients receiving head and neck radiation are at high risk for radiation caries. This study aimed to evaluate the remineralizing effects of an experimental 1.1% NaF (5000 ppmF) toothpaste containing Sr/F-doped bioactive glass nanoparticles (BAG or B) on demineralized irradiated dentin.

MATERIALS AND METHODS

Fluoride concentration and pH stability of materials upon mixing with water were assessed using a fluoride-specific electrode (n = 3) for up to 3 months. Elemental release of materials in water was determined using ICP-OES (n = 3). Fourteen extracted molars were irradiated with a cumulative dose of 70 Gy. Each tooth was sectioned into 4 specimens (n = 14/group), demineralized, and subjected to pH cycling for 14 days. Groups were treated with Prevident (PV), E5000, E5000B, and deionized water twice daily. Remineralization was assessed using ATR-FTIR (mineral-to-collagen ratio) (n = 14). Mineral precipitation was additionally examined with SEM-EDX. The in vitro cytotoxicity of the materials on L929 mouse fibrosarcoma was evaluated with the MTT test (n = 3). Kruskal-Wallis test, followed by Dunn's procedure, was used to compare the data between groups.

RESULT

PV demonstrated greater pH and fluoride release stability than the experimental materials. E5000B exhibited a slight reduction of fluoride release (p < 0.01, R²=0.656) and an increase in pH with time (p = 0.006, R²=0.233). The highest increase in mineral-to-collagen ratio at 14 days was detected with PV (p < 0.05). E5000B also showed a significantly higher ratio than E5000 (p = 0.014). SEM-EDX detected mineral precipitation on dentin treated with PV and E5000B but not in E5000 and DI. The cell viability of PV (56%) was significantly lower than that of E5000 (94%) and E5000B (89%) (p < 0.05).

CONCLUSION

The use of 5000 ppm fluoride toothpaste enhanced the remineralization of irradiated demineralized dentin, highlighting a potentially valuable strategy for preventing radiation caries. Adding bioactive glass further promoted remineralization but may require formulation adjustments to maintain toothpaste stability for clinical use.

Remineralization Effect of Bioactive Glass With and Without Fluoride and Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) on Artificial Dentine Caries: An In Vitro Study

Background/objectives Dentine hypersensitivity (DH) is a common dental condition marked by transient, sharp pain arising from dentinal exposure. Bioactive materials are capable of remineralization. This study aims to explore the remineralization effect of bioactive glass (BAG) with and without fluoride and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), using dentine discs as the test substrate. Materials and methods In this in vitro experimental study, 28 dentine discs were prepared from premolar teeth. Artificial caries were induced by subjecting the dentine discs to demineralization in acid for 72 hours. After demineralization, the discs were treated with various remineralizing dentifrices to evaluate their effects. The dentine discs (n=28) were divided into four groups: group 1 = BioMin (BioMin Technologies, London, United Kingdom), group 2 = NovaMin/Sensodyne Repair (GlaxoSmithKline plc, London, England, United Kingdom), group 3 = Recaldent (CPP-ACP; GC Orthodontics Inc., Alsip, Illinois, United States), and group 4 = deionized water (control group). All discs underwent a 28-day remineralization process using the respective dentifrices assigned to each group. The microhardness of the discs was measured using Vickers microhardness testing at three stages: baseline, post-demineralization, and post-remineralization. Results There was no significant difference in terms of microhardness between groups both at the baseline (F (3, 24) = 1.079, p = 0.995) and after the demineralization process (F (3, 24) = 1.310, p = 0.294). However, a significant difference was identified between the groups after the remineralization process (F (3, 24) = 34.008, p = 0.001). Additionally, the least significant difference (LSD) multiple comparison test was performed. There were significant differences identified in the remineralization condition, with group 1 having the highest values, followed by group 2, group 3, and group 4. Conclusion The results indicate that the remineralization effect on artificially induced dentine caries was more pronounced with bioactive glass containing fluoride compared to bioactive glass without fluoride and CPP-ACP.

Effect of silver diamine fluoride activation on bond strength to root dentin

BACKGROUND

To investigate the effect of silver diamine fluoride (SDF) application and activation on the bond strength of gutta-percha to dentin and resin bonded post to dentin.

METHODS

Thirty-six human premolar teeth were used. The coronal part tooth was removed, and endodontic mechanical preparation was performed for all the teeth. The teeth were divided according to final rinse protocol (n = 9) as follows: Control group; no SDF application, SDF/NA; 38% SDF as a final rinse with no activation, SDF/MDA; 38% SDF as a final rinse with manual dynamic activation and SDF/US; 38% SDF as a final rinse with ultrasonic activation. Root canal obturation using lateral condensation technique followed by fiber post insertion after 48 h in the root canal after corresponding preparations. The roots were cut with a low-speed precision saw creating 2 mm thickness sections. A total of 4 sections were obtained from each tooth, 2 coronal specimens (with post) and 2 apical specimens (with Gutta percha). Each specimen was subjected to push-out bond strength test with a universal testing machine. Data were analyzed using two-way ANOVA.

RESULTS

The Push-out bond strength at the apical root section was significantly higher in SDF/MDA and SDF/US groups compared to control group. While for the coronal part, all SDF treated specimen showed reduced Push-out bond strength.

CONCLUSION

SDF application as final rinse may reduce the bonding performance between fiber post and dentine. Activation with manual and ultrasonic methods improved the bond strength at the apical root section.

The Effect of Eggshell and Seashell Nanoparticles Alone and Combined With Nd: YAG Laser on Occlusion and Remineralization Potential of Patent Dentinal Tubules: An In Vitro Study

Introduction: There is an interest in developing materials with bioactive potential that could block exposed dentinal tubules. This study compared the effects of eggshell and seashell nanoparticles individually or combined with ND:YAG laser on dentinal tubules occlusion and remineralization. Methods: Fifty radicular dentin discs were prepared from freshly extracted human premolars. The smear layer created by cutting was removed using 37% phosphoric acid gel for 15 sec. The discs were divided into five groups according to the applied treatment(A) (n = 10 each): (A1) control, (A2); Nano eggshells, (A3); Nano seashells, (A4); Nano eggshells + Nd: YAG Laser, and (A5); Nano sea shell + Nd: YAG Laser. Each specimen was evaluated for tubular patency and mineral contents before and after each therapy using ESEM-EDXA energy dispersive spectroscopy for the assessment of tubule occlusion and remineralization. Results: ESEM results revealed a statistically significant decrease in the mean percent changes of the dentinal tubules number after the treatment of the experimental groups compared to the control. The greatest percent decrease was recorded in the seashell NPs + Nd: YAG laser, followed by the eggshell NPs + Nd: YAG laser, then Eggshell NPs only and then Seashell NPs only, while the lowest percentage decrease was recorded in the control group. EDXA revealed that the greatest percentage increase in Ca wt% was recorded in the Eggshell + Nd:YAG laser group, followed by Eggshell only, then Seashell only and then Seashell NPs + Nd: YAG laser, while the lowest percent increase was recorded in the control group. The post hoc test revealed no significant difference between the experimental groups. Conclusions: Both eggshell and seashell nanoparticles are effective in the occlusion and remineralization of dentinal tubules. The combined treatments with Nd: YAG laser had no benefits when compared to the effect of treatments alone.

Application of bioactive glasses in various dental fields

Bioactive glasses are a group of bioceramic materials that have extensive clinical applications. Their properties such as high biocompatibility, antimicrobial features, and bioactivity in the internal environment of the body have made them useful biomaterials in various fields of medicine and dentistry. There is a great variation in the main composition of these glasses and some of them whose medical usage has been approved by the US Food and Drug Administration (FDA) are called Bioglass. Bioactive glasses have appropriate biocompatibility with the body and they are similar to bone hydroxyapatite in terms of calcium and phosphate contents. Bioactive glasses are applied in different branches of dentistry like periodontics, orthodontics, endodontics, oral and maxillofacial surgery, esthetic and restorative dentistry. Also, some dental and oral care products have bioactive glasses in their compositions. Bioactive glasses have been used as dental implants in the human body in order to repair and replace damaged bones. Other applications of bioactive glasses in dentistry include their usage in periodontal disease, root canal treatments, maxillofacial surgeries, dental restorations, air abrasions, dental adhesives, enamel remineralization, and dentin hypersensitivity. Since the use of bioactive glasses in dentistry is widespread, there is a need to find methods and extensive resources to supply the required bioactive glasses. Various techniques have been identified for the production of bioactive glasses, and marine sponges have recently been considered as a rich source of it. Marine sponges are widely available and many species have been identified around the world, including the Persian Gulf. Marine sponges, as the simplest group of animals, produce different bioactive compounds that are used in a wide range of medical sciences. Numerous studies have shown the anti-tumor, anti-viral, anti-inflammatory, and antibiotic effects of these compounds. Furthermore, some species of marine sponges due to the mineral contents of their structural skeletons, which are made of biosilica, have been used for extracting bioactive glasses.

Zinc Oxide Nanoparticles: A Review on Its Applications in Dentistry

Nanotechnology in modern material science is a research hot spot due to its ability to provide novel applications in the field of dentistry. Zinc Oxide Nanoparticles (ZnO NPs) are metal oxide nanoparticles that open new opportunities for biomedical applications that range from diagnosis to treatment. The domains of these nanoparticles are wide and diverse and include the effects brought about due to the anti-microbial, regenerative, and mechanical properties. The applications include enhancing the anti-bacterial properties of existing restorative materials, as an anti-sensitivity agent in toothpastes, as an anti-microbial and anti-fungal agent against pathogenic oral microflora, as a dental implant coating, to improve the anti-fungal effect of denture bases in rehabilitative dentistry, remineralizing cervical dentinal lesions, increasing the stability of local drug delivery agents and other applications.

Synergistic effect of graphene oxide/calcium phosphate nanofiller in a dentin adhesive on its dentin bond integrity and degree of conversion. A scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared, micro-Raman, and bond strength study

The objective was to formulate and analyze a dentin adhesive incorporated with graphene oxide (GO) nanoparticle and calcium phosphate (CaP) composite. Methods comprising of scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy, shear bond strength (SBS), and Fourier transform infrared (FTIR) spectroscopy were used to characterize nanoparticle composite, dentin bond toughness, degree of conversion (DC), and adhesive-dentin interaction. Postsynthesis of GO nanoparticles, they were functionalized with CaP using standard process. The GO-CaP composite was not added to experimental adhesive (negative control group, GO-CaP-0%), and added at 2.5 and 5 wt% to yield GO-CaP-2.5% and GO-CaP 5% groups, respectively. Teeth were set to form bonded samples utilizing adhesives in three groups for SBS testing, with and without thermocycling. The homogenous diffusion of GO-CaP composite was verified in the adhesive. Resin tags having standard penetrations were observed on SEM micrographs. The EDX analysis confirmed the occurrence of calcium, phosphorus, and carbon ions in the composite containing adhesives. The SBS test revealed highest mean values for GO-CaP-5% followed by GO-CaP-2.5%. The FTIR spectra verified the presence of apatite peaks and the micro-Raman spectra showed characteristic D and G bands for GO nanoparticles. GO-CaP composite in dentin adhesive may improve its bond strength. The addition of 5 wt% resulted in a bond strength that was superior to all other groups. GO-CaP-5% group demonstrated lower DC (to control), uniform distribution of GO and CaP composite within adhesive, appropriate dentin interaction, and resin tag formation.

Dentin Bond Integrity of Hydroxyapatite Containing Resin Adhesive Enhanced with Graphene Oxide Nano-Particles-An SEM, EDX, Micro-Raman, and Microtensile Bond Strength Study

The aim was to synthesize and characterize an adhesive incorporating HA and GO nanoparticles. Techniques including scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), micro-tensile bond strength (μTBS), and micro-Raman spectroscopy were employed to investigate bond durability, presence of nanoparticles inside adhesive, and dentin interaction. Control experimental adhesive (CEA) was synthesized with 5 wt% HA. GO particles were fabricated and added to CEA at 0.5 wt% (HA-GO-0.5%) and 2 wt% GO (HA-GO-2%). Teeth were prepared to produce bonded specimens using the three adhesive bonding agents for assessment of μTBS, with and without thermocycling (TC). The adhesives were applied twice on the dentin with a micro-brush followed by air thinning and photo-polymerization. The HA and GO nanoparticles demonstrated uniform dispersion inside adhesive. Resin tags with varying depths were observed on SEM micrographs. The EDX mapping revealed the presence of carbon (C), calcium (Ca), and phosphorus (P) in the two GO adhesives. For both TC and NTC samples, HA-GO-2% had higher μTBS and durability, followed by HA-GO-0.5%. The representative micro-Raman spectra demonstrated D and G bands for nano-GO particles containing adhesives. HA-GO-2% group demonstrated uniform diffusion in adhesive, higher μTBS, adequate durability, and comparable resin tag development to controls.

Influence of Hydroxyapatite Nanospheres in Dentin Adhesive on the Dentin Bond Integrity and Degree of Conversion: A Scanning Electron Microscopy (SEM), Raman, Fourier Transform-Infrared (FTIR), and Microtensile Study

An experimental adhesive incorporated with different nano-hydroxyapatite (n-HA) particle concentrations was synthesized and analyzed for dentin interaction, micro-tensile bond strength (μTBS), and degree of conversion (DC). n-HA powder (5 wt % and 10 wt %) were added in adhesive to yield three groups; gp-1: control experimental adhesive (CEA, 0 wt % HA), gp-2: 5 wt % n-HA (HAA-5%), and gp-3: 10 wt % n-HA (HAA-10%). The morphology of n-HA spheres was evaluated using Scanning Electron Microscopy (SEM). Their interaction in the adhesives was identified with SEM, Energy-Dispersive X-ray (EDX), and Micro-Raman spectroscopy. Teeth were sectioned, divided in study groups, and assessed for μTBS and failure mode. Employing Fourier Transform-Infrared (FTIR) spectroscopy, the DC of the adhesives was assessed. EDX mapping revealed the occurrence of oxygen, calcium, and phosphorus in the HAA-5% and HAA-10% groups. HAA-5% had the greatest μTBS values followed by HAA-10%. The presence of apatite was shown by FTIR spectra and Micro-Raman demonstrated phosphate and carbonate groups for n-HA spheres. The highest DC was observed for the CEA group followed by HAA-5%. n-HA spheres exhibited dentin interaction and formed a hybrid layer with resin tags. HAA-5% demonstrated superior μTBS compared with HAA-10% and control adhesive. The DC for HAA-5% was comparable to control adhesive.

Preparation of a toothpaste containing theobromine and fluoridated bioactive glass and its effect on surface micro-hardness and roughness of enamel

The aim was to synthesize a toothpaste and analyze its effect on surface micro-hardness and roughness of enamel. Basic paste was prepared by using basic ingredients. Theobromine (0.2 wt%) and laboratory synthesized fluoridated-bioactive glass (F-BG, 4 wt%) were added to it. Post-demineralization, 36 enamel blocks were divided into six groups that were brushed with their respective toothpaste+artificial saliva (AS): group 1 (control): basic paste; group 2: basic paste+theobromine; group 3: commercial theobromine toothpaste; group 4: commercial BG toothpaste; group 5: basic paste+F-BG; and group 6: basic paste+theobromine+F-BG. On micro-hardness analysis, group 6 performed best, followed by group 4. Surface roughness results showed the maximum decrease in roughness values for group 6, followed by group 5. Treatment with toothpaste composition containing theobromine+F-BG resulted in the enamel's increased micro-hardness and decreased surface roughness.

Sylc Air Polishing Versus Fluoride Varnish Application in Managing Dentin Hypersensitivity in Non-Carious Cervical Lesions: A Randomized Clinical Trial

Objective:

To determine the effectiveness of Sylc (a bioactive glass-based powder) delivered by an air polishing system compared to fluoride varnish application in managing Dentin Hypersensitivity (DH).

Methods:

This study was a double-blinded randomized clinical trial where 50 participants with DH in at least one tooth with a non-carious cervical lesion were included and randomized into two groups (25 participants each) to receive either Sylc air polishing or fluoride varnish application. Baseline and post-intervention measurements of pain were carried out using evaporative, thermal and tactile stimuli using a modified visual analog scale at 3 minutes, 1, 2, 3and 4 weeks, 6 months and 1 year post-intervention. Data for pain intensity was recorded and analyzed for each group.

Results:

For the three stimuli used, Sylc air polishing showed statistically significant reduction of pain intensity (P<0.05) after 3 weeks and up to 1 year post-intervention. Fluoride varnish application showed a statistically significant reduction of pain intensity in evaporative and thermal stimuli at 1 week post-intervention only.

Conclusion:

Sylc air polishing was effective in relieving pain due to DH after 3 weeks and up to 1 year post-intervention, which showed that it can be used as a long-term treatment for DH.

Sylc Air Polishing Versus Fluoride Varnish Application in Managing Dentin Hypersensitivity in Non-Carious Cervical Lesions: A Randomized Clinical Trial

Objective:

To determine the effectiveness of Sylc (a bioactive glass-based powder) delivered by an air polishing system compared to fluoride varnish application in managing Dentin Hypersensitivity (DH).

Methods:

This study was a double-blinded randomized clinical trial where 50 participants with DH in at least one tooth with a non-carious cervical lesion were included and randomized into two groups (25 participants each) to receive either Sylc air polishing or fluoride varnish application. Baseline and post-intervention measurements of pain were carried out using evaporative, thermal and tactile stimuli using a modified visual analog scale at 3 minutes, 1, 2, 3and 4 weeks, 6 months and 1 year post-intervention. Data for pain intensity was recorded and analyzed for each group.

Results:

For the three stimuli used, Sylc air polishing showed statistically significant reduction of pain intensity (P<0.05) after 3 weeks and up to 1 year post-intervention. Fluoride varnish application showed a statistically significant reduction of pain intensity in evaporative and thermal stimuli at 1 week post-intervention only.

Conclusion:

Sylc air polishing was effective in relieving pain due to DH after 3 weeks and up to 1 year post-intervention, which showed that it can be used as a long-term treatment for DH.