Evaluating the Effect of Tideglusib-Loaded Bioactive Glass Nanoparticles as a Potential Dentine Regenerative Material.

Dental pulp treatment is the least intrusive procedure currently available for preserving the vitality of the pulp. Several studies are underway to improve the bioactivity of pulp capping materials. Tideglusib isa potent anti-inflammatory, antioxidant, and a regenerative drug developed against Alzheimer's disease and has been shown to be effective in the treatment of dental cavities. However, its bioactive properties encapsulated within the nanoparticles as a component of pulp capping material are largely unknown. In this study, tideglusib-loaded bioactive glass nanoparticles were synthesized (tideglusib-BgNPs) and mixed at various concentrations into the calcium silicate cement to testits physiomechanical and bioactivitiescompared with biodentine (control). The calcium silicate cement with 10wgt% tideglusib-BgNPs showed comparable physiomechanical properties to that of biodentine. Additionally, the assessment of cytotoxicity and bioactivity (cell proliferation, wound healing, and cell migration assays) showed increased bioactivity in terms of better wound healing, increased proliferation, and better migration of human dental pulp stem cells than biodentine. These findings suggest new opportunities to use tideglusib-BgNPs in pulp therapy.

Evaluation of Micro-Tensile Bond Strength of Fibre Post with Titanium Dioxide Nanoparticles as Fillers in Experimental Dental Composite Resin.

BACKGROUND: The clinical success of post-core restorations is determined by the composite utilized and the strength of the post-core adhesion. The effectiveness of titanium dioxide nanoparticles (TiO2 NPs) as a multifunctional material with photo-induced activities and better mechanical characteristics are observed as particle size is reduced to under 50 nm. AIM: The purpose of this study is to determine the bond strength of fibre-reinforced composite (FRC) posts with TiO2 NP as fillers and to compare it with conventional composite resin core material. MATERIALS AND METHODS: 30 single-rooted mandibular premolars were selected and routine root canal procedures were done. A quantity of 5% TiO2 NPs were synthesized and added as silanized filler to the experimental composite resin. Post space was prepared and fibre-reinforced composite (FRC) post luting was performed. The specimens were then grouped into the following groups: Group I consisted of the experimental composite resin containing 5% TiO2 fillers, Group II consisted of core X flow, and Group III consisted of Multicore Flow. All test groups were submitted for thermocycling. After this, the samples were tested for micro tensile bond strength. A stereomicroscope with a magnification of 20× was used to examine the fractured surfaces. The data were analysed using one-way ANOVA and Tukey HSD tests. RESULTS: Statistical analysis revealed that Group I showed the highest mean bond strength value of 35.6180 Mpa. The results obtained with Group III showed the lowest mean bond strength value of 19.4690 Mpa. Adhesive failures were identified by stereomicroscopy of the fractured surfaces. CONCLUSION: The experimental composite resin comprising 5% TiO2 NP had a greater bond to the FRC post than other materials tested.

Development of Novel Antimicrobial Dental Composite Resin with Nano Cerium Oxide Fillers.

Objectives: To assess the antibacterial efficacy of experimental dental composite resin with cerium oxide nanoparticles as fillers. Methods: The cerium oxide nanoparticles were prepared by the coprecipitation procedure. Synthesized 3wt% CeO2 nanoparticles were added to the composite resin as antibacterial filler. Experimental composite resin was manually prepared by adding ingredients. The resin matrix consisted of two mixed monomers, bisphenol A-glycidyl methacrylate and triethylene glycol dimethacrylate, diketone as the photo initiator, and N, N-dimethylaminoethyl methacrylate as a coinitiator. The antibacterial efficacy against Streptococcus mutans, Streptococcus mitis, Streptococcus aureus, and Lactobacillus spp. bacterial strains was tested using the microdilution method keeping commercially available 3M Filtek Z250 restorative composite as control. Results: The experimental dental composite demonstrated 99.503% efficacy against Streptococcus mutans, 99.441% efficacy against Streptococcus mitis, 99.416% efficacy against Streptococcus aureus, and 99.233% efficacy against Lactobacillus spp. Conclusion: Integrating cerium oxide nanoparticles as fillers into dental composite resin can be promising in terms of antibacterial activity, provided furthermore study has to be conducted to examine other properties. Clinical Significance. Previous studies attempted adding CeO2 nanoparticles into acrylic resins that showed improvement in mechanical properties, but literature is nil on the dental composite resin and cerium oxide nanoparticles. This study demonstrates the development of an experimental antibacterial dental composite resin that can resolve most of the problems related to secondary caries around dental composite restorations.

Comparative Evaluation of Mechanical Properties of Titanium Dioxide Nanoparticle Incorporated in Composite Resin as a Core Restorative Material.

AIM: To compare and evaluate the mechanical properties of 2.5% titanium dioxide nanoparticle (TiO2 NP) incorporated as filler in an experimental composite resin with everX Flow and MultiCore Flow. MATERIALS AND METHODS: TiO2 was prepared and incorporated into experimental dental composite resin. The experimental and traditional composite resin was grouped as follows: Group I: The experimental composite resin with 2.5% of TiO2 fillers, Group II: everX Flow (GC EUROPE), and Group III: MultiCore Flow (Ivoclar Vivadent). Based on International Standards Organization (ISO) 4049, the samples were prepared for the compressive, diametral tensile, and flexural test. RESULTS: Statistical analysis was done, and the results were tabulated. Compared to the other tested materials, the experimental composite resin had relatively high compressive strength, diametral tensile strength, and flexural strength. Compared to MultiCore Flow, the everX Flow showed strong mechanical properties. CONCLUSION: Based on the result of the study, it can be concluded that the 2.5% TiO2 NP incorporated as filler in an experimental composite resin demonstrated higher mechanical properties compared to the conventional material. CLINICAL SIGNIFICANCE: The unique photoactivities of TiO2 NP and their superior mechanical properties make them one of the ideal additives to enhance the performance of polymeric materials.

Comparative Efficacy of Resin Infiltrant and Two Remineralizing Agents on Demineralized Enamel: An In Vitro Study.

AIM: To compare and evaluate the caries preventive effectiveness of resin infiltrant (ICON), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (GC Tooth Mousse), and nanohydroxyapatite (Aclaim) on incipient enamel lesions. MATERIALS AND METHODS: A total of 60 human maxillary incisors extracted for periodontal reasons were included in this study. The sectioning was done at the middle third region of the crown for the 60 samples with approximate dimensions of 5 × 5 × 5 mm). In order to create the artificial enamel lesions, the samples were demineralized by placing in a beaker containing the prepared demineralizing solution for 14 days. The study samples were then divided into four groups that are resin infiltrant (group I), CPP-ACP (group II), nanohydroxyapatite (group III), and control (group IV) with 15 enamel samples in each group. The caries preventive efficacy of each group was evaluated using a confocal laser scanning microscope. RESULTS: The mean values after demineralization of enamel samples in demineralizing solution are 245 µm for resin infiltrant (group I), 246 µm for CPP-ACP (group II), 250 µm for nanohydroxyapatite (group III), and 247 µm for control (group IV). After remineralizing the enamel samples for a period of 30 days, the results are group I (resin infiltrant) 158 µm > group II (CPP-ACP) 28.8µm ≥ group III (nanohydroxyapatite) 26.3 µm. After subjecting it to demineralizing solution again for 14 days, the amount of material that was resistant to acid attack was group I (resin infiltrant) 114 µm (72%) > group III (CPP-ACP) 16.4 µm (57%) ≥ group III (nanohydroxyapatite) 13.8 µm (50%). The untreated control group showed increased progression of lesion and least resistance to acid challenge. CONCLUSION: Based on the results from this in vitro study, it can be concluded that when compared to the two remineralizing agents the resin infiltrant showed better caries preventive effectiveness. CLINICAL SIGNIFICANCE: Resin infiltrants have a favorable penetration potential in subsurface or incipient enamel lesions.

The effect of leachable components of resin cements and its resultant bond strength with lithium disilicate ceramics.

OBJECTIVES: To evaluate the leachable components of resin cements in oral simulating fluids using high performance liquid chromatography and its resultant shear bond strength with ceramics. METHODS: Forty extracted permanent human mandibular molar teeth were sectioned horizontally with a disc beneath the dentino-enamel junction to expose the coronal dentin surface and later finished with 600-grit silicon carbide paper to create a uniform flat surface. Forty Lithium Di-silicate Ceramic block cylinders were sliced in a saw cutting machine at 250 rpm under water-cooling to obtain the discs. The teeth and the ceramic discs were then randomly assigned to two groups on the basis of material used for luting the ceramic disk. Group I: Ceramic disc luted with tooth surface using Variolink II Dual cure Resin Cement, Group II: Ceramic disc luted with tooth surface using multilink speed self-adhesive self-curing resin cement. All ceramic discs were etched with 5% HF acid (IPS Ceramic Etching Gel, Ivoclar, Schaan, Liechtenstein) for 20 seconds, then rinsed thoroughly for 20 seconds and dried for 20 seconds. Ceramic specimens were luted on dentin surfaces with the application of 5 kg load. The samples were stored in 75% ethanol solution for 2 weeks at 37 degree Celsius for chemical aging. HPLC Analysis were performed to analyze the eluted monomer. After HPLC Analysis, Samples were then loaded using universal testing machine for the evaluation of shear bond strength between ceramic discs and the resin cements before and after the elution of monomers. RESULTS: Under HPLC analysis, results showed that the peak release of monomer is Bis-GMA in both the groups. The shear force required to break the bond between the ceramic luted to tooth surface with the resin cements were more for Group I. Statistical results: The statistical analysis was done using ANOVA and paired t-test and it shows P value ≥0.05, hence the null hypothesis is rejected. CONCLUSION: The monomer eluded from all the groups are identified as Bis-GMA, The eluded monomer decreases the bond strength between the resin cement and the ceramic due to water sorption, The Variolink II (dual cure) resin cement shows improved bond strength than the Multilink (self-cure self-adhesive) resin cement.

Comparative Evaluation of Stress developed on Rotary Retreatment Instruments during Retrieval of Gutta-percha.

AIM: The aim of the study is to compare the maximum stress distribution on the rotary retreatment instruments within the root canal at cervical, middle, and the apical one-third during retreatment of gutta-percha. MATERIALS AND METHODS: A human mandibular premolar was scanned, and three-dimensional geometry of the root was reconstructed using finite element analysis (FEA) software package (ANSYS). The basic model was kept unchanged; tooth models were created using the same dimensions and divided into two groups as follows: Group I: ProTaper Universal retreatment system and group II: Mtwo rotary retreatment system. The stress distribution on the surface and within the retreatment files was analyzed numerically in the FEA package (ANSYS). RESULTS: The FEA analysis revealed that the retreatment instruments received the greatest stress in the cervical third, followed by the apical third and the middle third. The stress generated on the ProTaper Universal retreatment system was less when compared with the Mtwo retreatment files. CONCLUSION: The study concludes that the retreatment instruments undergo higher stress in the cervical third region, and further in vivo and in vitro studies are necessary to evaluate the relationship between instrument designs, stress distribution, residual stresses after use, and the torsional fracture of the retreatment instrument. CLINICAL SIGNIFICANCE: The stress developed on the rotary retreatment instruments during retrieval of gutta-percha makes the instrument to get separated. There is no instrument system, i.e., suitable for all clinical situations and it is important to understand how the structural characteristics could influence the magnitude of stresses on the instrument to prevent its fracture in use.