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STATEMENT OF PROBLEM: Quaternary ammonium (QA)-based monomers such as dimethyl-hexadecyl-methacryloxyethyl-ammonium iodide (DHMAI) and 2-dimethyl-2-dodecyl-1-methacryloxyethyl ammonium iodine (DDMAI) have been investigated as copolymerizable monomers to impart antimicrobial activity to dental restorative and prosthetic materials. However, the biocompatibility of these antimicrobial monomers needs to be investigated in vivo before their clinical use. PURPOSE: The purpose of this study was to assess the in vivo biocompatibility of polymethyl methacrylate (PMMA) heat-polymerizing denture base resin copolymerized with varying concentrations of DHMAI and DDMAI. MATERIAL AND METHODS: The toxicity and genotoxicity of the antimicrobial monomers (DHMAI 5 µg/mL and DDMAI 20 µg/mL) at 1 to 100 µg/mL concentrations were investigated against zebrafish embryos (Danio rerio, n=10) using a zebrafish embryotoxicity test (ZET) or fish embryotoxicity test (FET) and comet assay, respectively. Further, DHMAI 5 µg/mL and DDMAI 20 µg/mL were incorporated into a conventional PMMA denture base system and a similar test was done on specimens of modified PMMA resin. For the evaluation of in vivo biocompatibility, modified PMMA specimens were subcutaneously implanted into Wistar rats (n=6) and biochemical, hematological, and histopathological parameters were investigated. Results were analyzed and compared using ANOVA and the Tukey post hoc test (α=.05). RESULTS: Toxicity and genotoxicity studies using zebrafish embryos revealed that the incorporation of monomer to PMMA did not increase the toxicity, as confirmed by post-hour fertilization. Modified PMMA did not affect the hematological parameters, such as red blood cell (RBC) and white blood cell (WBC) except for the platelet count, which was significantly increased (P<.001), and the biochemical parameter, such as total protein (TP), blood urea nitrogen (BUN), serum glutamic-oxaloacetic transaminase (SGOT), triglyceride (TG), creatinine (Crea), total cholesterol, and serum glutamic pyruvic transaminase (SGPT), except for high-density lipoprotein (HDL) cholesterol, which was significantly decreased (P<.01). Histopathologically, no changes were observed in the sections of the liver, kidney, spleen, and subcutaneous tissues in the modified PMMA implanted rats. Additionally, no significant variation was found in the expression of immunohistochemical marker tumor necrosis factor alpha (TNF-α), confirming the noninflammatory response exerted by the modified PMMA on experimental rats. CONCLUSIONS: Zebrafish embryos treated with modified PMMA specimens demonstrated favorable biological properties and did not exhibit significant cytotoxicity and genotoxicity. Subcutaneously implanted modified PMMA did not cause any major hematological, biochemical, and histopathological alterations in Wistar albino rats, thus confirming the biocompatibility of PMMA heat-polymerizing denture base resin incorporated with DHMAI and DDMAI for dental applications.
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Background: This study investigates various surface treatment methods to assess shear bond strength between set Cention N (alkasite-based restorative material) and new alkasite based restorative material. Assessing different surface treatments provide insights in optimizing repair procedure that enables durability of the restoration, thus potentially benefitting clinical outcomes. Methods: A total of 48 alkasite based restorative material blocks, measuring 4 mm in depth and 4 mm in diameter, were prepared. The samples were randomly divided into 8 groups (n = 6) according to the surface treatment done. Group I: Surface preparation by bur; Group II: Surface treatment by laser; Group III: Application of 2-step etch and rinse adhesive (Adper Single Bond 2 adhesive),Group IV: Application of single step self-etch adhesive (Scotchbond Universal adhesive); Group V: Bur preparation followed by application of 2-step etch and rinse adhesive; Group VI: Bur preparation followed by application of single step self-etch adhesive; Group VII: Laser preparation followed by application of 2-step etch and rinse adhesive; and Group VIII: Laser preparation followed by application of single step self-etch adhesive. Post-surface preparation, all the specimens were restored with newly mixed alkasite material. Repair bond strength measurements were assessed with universal testing machine. Shapiro-Wilk and Levene's tests were used to check normality and Homogeneity of variance. ANOVA with post-hoc Games-Howell test and two-way ANOVA with post-hoc Bonferroni test was performed to evaluate the influence of surface preparation on the repair bond strength. Results: Using a 2-step etch and rinse adhesive resulted in a higher repair bond strength (26.05±2.12) compared to other surface treatments. In contrast, roughening of the surface with burs led to lowest repair bond strength (17.06±3.29) (P=0.02). Conclusion: Application of 2-step etch and rinse adhesive to the existing alkasite based restorative material provides superior bonding with the newly added alkasite based restorative material.
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Recubrimiento Dental Adhesivo , Propiedades de Superficie , Recubrimiento Dental Adhesivo/métodos , Resistencia al Corte , Materiales Dentales/química , Ensayo de Materiales , Humanos , Restauración Dental Permanente/métodosRESUMEN
AIM: The aim of the study is to determine the difference in the shear bond strengths to dentin among dental composite (Filtek Z350®, 3M), compomer (Dyract Flow®, Dentsply) and Giomer (Beautifil®, Shofu) with 3MTM Single BondTM Universal Adhesive (SBU) (7th generation, self-etch, single solution adhesive) and AdperTM Single Bond 2 Adhesive (ASB) (5th generation, total-etch, two solution adhesive). MATERIALS AND METHODS: Sixty extracted human permanent teeth were collected, cleansed of debris, and placed in distilled water. The samples were segregated into two groups depicting the two bonding agents-AdperTM (ASB) and 3MTM Single Bond Universal (SBU) and sub-grouped into three groups depicting the three restorative materials (Composite, Giomer, and Compomer) used. Groups were respresented as follows: Group I-ASB + Composite; Group II-ASB + Giomer; Group III-ASB + Compomer; Group IV-SBU + Giomer; Group V-SBU + Compomer; Group VI-SBU + Composite. After applying the bonding agent as per the manufacturer's instructions, following which the restorative material was placed. A Universal Testing Machine (Instron 3366, UK) was employed to estimate the shear bond strength of the individual restorative material and shear bond strengths were calculated. RESULTS: Composite bonded with SBU (group VI) displayed the greatest shear strength (11.16 ± 4.22 MPa). Moreover, Giomers and flowable compomers displayed better bond strengths with ASB compared with their SBU-bonded counterparts. CONCLUSION: These results mark the importance of careful material selection in clinical practice and the bonding agent used to achieve optimal bond strength and enhance the clinical longevity and durability of dental restorations. CLINICAL SIGNIFICANCE: From a clinical perspective, to avoid a compressive or a shear failure, it would be preferrable to use a direct composite restorative material with SBU (Single bond universal adhesive, 7th generation) to achieve maximum bond strength. How to cite this article: Kuchibhotla N, Sathyamoorthy H, Balakrishnan S, et al. Effect of Bonding Agents on the Shear Bond Strength of Tooth-colored Restorative Materials to Dentin: An In Vitro Study. J Contemp Dent Pract 2024;25(3):245-249.
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Compómeros , Resinas Compuestas , Recubrimiento Dental Adhesivo , Análisis del Estrés Dental , Recubrimientos Dentinarios , Dentina , Resistencia al Corte , Resinas Compuestas/química , Humanos , Recubrimiento Dental Adhesivo/métodos , Recubrimientos Dentinarios/química , Técnicas In Vitro , Compómeros/química , Bisfenol A Glicidil Metacrilato , Restauración Dental Permanente/métodos , Ensayo de Materiales , Cementos de Ionómero Vítreo/química , Materiales Dentales/química , Resinas Acrílicas/químicaRESUMEN
Methods: 22 specimens prepared with Cention and RMGIC were embedded in primary teeth mounted in acrylic for analysing shear bond strength. Shear bond strength was analysed using a universal testing machine. The modes of failure in samples were observed under a stereomicroscope and scanning electron microscope. 22 customised samples of Cention N and RMGIC were prepared and categorised as group A and group B, respectively. The flexural and compressive strengths of these samples were evaluated using a universal testing machine. Results: The shear bond strength of RMGIC was higher than that of Cention N, whereas the compressive and flexural strengths of Cention N were significantly higher than those of RMGIC. The modes of failure were predominantly adhesive followed by mixed failures. Conclusion: The results of this study suggest that Cention N demonstrated superior mechanical properties compared with RMGIC and can therefore be recommended for restorations in primary posterior teeth. Cention N being a smart, esthetic, self-cured, or dual-cured material with better mechanical properties offers a wide range of applicability in primary teeth.
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Cementos de Ionómero Vítreo , Diente Primario , Fuerza CompresivaRESUMEN
Background: To compare the surface roughness and microhardness of Ceram.x® SphereTEC™ one and Filtek Z350 XT after in-office bleaching with Pola office. Methods: Twenty samples each of (10 mm diameter and 2 mm height) Ceram.x® SphereTEC™ one and Filtek Z350 XT were prepared. The samples were subjected to three bleaching sessions with 35% hydrogen peroxide (Pola office) with a seven-day interval between each session. Surface roughness and microhardness of the prepared samples prior to and after the bleaching regimen were measured using a profilometer and Vickers hardness tester, respectively. Results: A significant reduction (p <0.001) in the surface hardness of Filtek Z350 XT from 27.67 ± 2.10 to 17.83 ± 1.36 Vickers hardness number (VHN) was observed after the bleaching whereas no significant reduction in surface hardness was observed with Ceram.x® SphereTEC™ one. The adjusted mean (estimated marginal mean) microhardness after bleaching for Ceram.x ® SphereTEC™ one (35.79 ± 1.45) was significantly higher than Filtek Z350 XT (19.54 ± 1.45) (p < 0.001). However, in-office bleaching of these materials did not significantly alter their surface roughness. Conclusions: In office-bleaching with 35% hydrogen peroxide can reduce the microhardness of nanofilled composite. However, the surface roughness was not influenced by the bleaching procedure in both nanohybrid and nanofilled composite resin materials.
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Blanqueadores , Peróxido de Hidrógeno , Resinas CompuestasRESUMEN
In recent years, the application of lasers for modifying the surface topography of dental biomaterials has received increased attention. This review paper aims to provide an overview of the current status on the utilization of lasers as a potential tool for surface modification of dental biomaterials such as implants, ceramics, and other materials used for restorative purposes. A literature search was done for articles related to the use of lasers for surface modification of dental biomaterials in English language published between October 2000 and March 2023 in Scopus, Pubmed and web of science, and relevant articles were reviewed. Lasers have been mainly used for surface modification of implant materials (71%), especially titanium and its alloys, to promote osseointegration. In recent years, laser texturing has also emerged as a promising technique to reduce bacterial adhesion on titanium implant surfaces. Currently, lasers are being widely used for surface modifications to improve osseointegration and reduce peri-implant inflammation of ceramic implants and to enhance the retention of ceramic restorations to the tooth. The studies considered in this review seem to suggest laser texturing to be more proficient than the conventional methods of surface modification. Lasers can alter the surface characteristics of dental biomaterials by creating innovative surface patterns without significantly affecting their bulk properties. With advances in laser technology and availability of newer wavelengths and modes, laser as a tool for surface modification of dental biomaterials is a promising field, with excellent potential for future research.
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Introduction: Clinicians should be aware of any effect the oral environment may have on archwires. Laboratory models fail to closely imitate intraoral conditions. The aim was to evaluate the change in mechanical properties of preformed stainless steel archwires after 15 weeks of exposure to the oral environment. Methods: Three commercially manufactured 0.019 × 0.025â³ stainless steel archwires were evaluated. Young's modulus, yield strength, spring factor, and hardness were studied. The unexposed distal end cuts (control samples) and archwires were tested after 15 weeks of intraoral exposure (test samples). Tension tests, Vickers microhardness tests, and nanoindentation tests were carried out. Results: Normality was tested using the Shapiro-Wilk test. Statistical analyses included the paired t-test for intragroup comparisons and Kruskal-Wallis ANOVA with the post hoc Dunn test for comparison of mean percentage reduction in values. At T15, Young's modulus showed a statistically significant decrease. Changes in yield strength and spring factor were not significant for groups other than American Orthodontics wires. The reduction in hardness was significant in 3M Unitek. Vickers, tension, and nanoindentation tests demonstrated an expansive range between hardness and Young's modulus so determined. Conclusion: 3M Unitek archwires showed the highest difference in Young's modulus. Yield strength values increased in Ortho Organizers archwires. Spring factor decreased only in 3M Unitek archwires. Hardness values obtained from various tests did not produce identical results.
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Soportes Ortodóncicos , Acero Inoxidable , Ensayo de Materiales , Propiedades de Superficie , Módulo de Elasticidad , Alambres para Ortodoncia , Titanio , Aleaciones DentalesRESUMEN
Aim: The present study was aimed to investigate the functional relationship between the mixing temperature and properties of a commercially available zinc oxide eugenol impression paste (ZnOE paste). Settings and Design: In-vitro study. Materials and Methods: A custom-made simulated mixing device was indigenously designed to maintain different mixing temperatures, simulating cold, ambient, and hot weather. A commercially available ZnOE paste was mixed according to the manufacturer's instructions in the simulated mixing device at the temperatures ranging from 10°C to 50°C. Initial setting time and consistency were measured according to A. D. A. Specification No. 16 (n = 8). A stainless-steel die having 25, 50, and 75 µm lines was used for surface detail reproduction. Detail reproduction of the stone casts of the impressions was evaluated with a stereomicroscope at 30 magnification (n = 8). The shear bond strength of ZnOE paste to self-cure acrylic tray resin was measured by using the UTM at a crosshead speed of 0.5 mm/min (n = 8). Statistical Analysis Used: Data were analyzed by using one-way analysis of variance (ANOVA) and Tukey's post hoc tests at a confidence interval of 95% (alpha =0.05). Results: Initial setting time, consistency, and detail reproduction of the ZnOE paste were affected by the mixing temperature (P < 0.001). Mixing ZnOE paste at a lower temperature of 10°C and higher temperatures of 40°C and 50°C resulted in shorter initial setting time, thicker consistency, and poor detail reproduction. However, no significant difference was obtained in the shear bond strength among the different mixing temperatures evaluated (P > 0.05). Conclusion: Based on this in vitro study, it is advisable to perform the manipulation of ZnOE paste at a clinical/laboratory temperature of 30°C for optimum performance. The simulated mixing device used in this study can be an alternative for extreme climatic conditions.
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Eugenol , Óxido de Zinc , Cemento de Óxido de Zinc-Eugenol , Resinas Acrílicas , Regulación de la Temperatura CorporalRESUMEN
The main objective of the present study was to evaluate the effect of the morphology of titanium dioxide nanofillers on the flexural strength and shear bond strength of the dental composite. Spherical and rhombic-shaped nano titanium dioxide fillers were synthesized via solvothermal method and were characterized. Subsequently, these fillers were incorporated into a flowable composite (Filtek™ Z350 XT Flowable Restorative) at 0.5 wt.% and 1.5 wt.% and the prepared specimens were stored in water for 24 h. The specimens were then evaluated for flexural strength using a universal testing machine. Similarly, the shear bond strength of modified composites to the tooth was evaluated and bond failures were analyzed using stereomicroscope magnification. Incorporation of nanofillers significantly enhanced the flexural strength of flowable composite (p = 0.009) with a significant increase at 0.5wt.% of spherical (p = 0.015) and rhomboidal-shaped fillers (p = 0.010). However, no statistically significant difference in flexural strength was observed among the different shapes of nanofillers. The results of our study did not show a significant effect on the shear bond strength of the composites. Thus the reinforcing ability of titanium dioxide nanofillers on dental composite was confirmed in this study, although the effect of using nanofillers with different morphology was not significant.
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Resinas Compuestas , Resistencia Flexional , Ensayo de Materiales , Resinas Compuestas/química , Resistencia al Corte , Propiedades de SuperficieRESUMEN
The present study aims to synthesize and characterize two quaternary ammonium (QAM) based monomers such as - dimethyl-hexadecyl-methacryloxyethyl-ammonium iodide (DHMAI) and 2-dimethyl-2-dodecyl-1-methacryloxyethyl ammonium iodine (DDMAI) and assess their cytotoxicity and antimicrobial properties. The study also aims to incorporate the optimized concentration of these monomers as copolymerizing monomers into conventional Polymethyl methacrylate (PMMA) denture base resin and evaluate their suitability for prosthetic applications. DHMAI and DDMAI monomers were synthesized through a Menschutkin reaction and their chemical structure was characterized using FT-IR and 1H-NMR spectroscopy. Cytotoxicity was determined using Methyl Thiazolyl Tetrazolium (MTT) assay whereas antimicrobial activity was assessed using the agar-disc diffusion method. Subsequently, optimized concentrations of DHMAI or DDMAI, based on the cytotoxicity results, were added to conventional PMMA resin. Antimicrobial activity, cytotoxicity, surface hardness, and water sorption of PMMA denture base rein incorporated with DHMAI or DDMAI were evaluated. FT-IR and 1H-NMR results confirmed the structure of monomers and copolymerization of DHMAI and DDMAI with PMMA resin. DHMAI and DDMAI monomers were found to be cytocompatible with mouse fibroblast cells up to a concentration of 5 µg/mL and 20 µg/mL respectively. In addition, incorporation of DHMAI or DDMAI at 5 µg/mL and 20 µg/mL respectively into PMMA denture base material did not affect their cytocompatibility. PMMA denture base resin incorporated with DHMAI or DDMAI significantly reduced the adhesion of microbes. Further, an increase in the surface hardness and a reduction in the water sorption was observed. Hence DHMAI and DDMAI can be considered as potential candidates for imparting antimicrobial activity to polymeric denture base materials.
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Purpose: To study the effect of different surface treatments on the micro-shear bond strength and surface characteristics of zirconia. Methods: Two types of zirconia ceramics were tested: opaque (O) and translucent (T). Each type of zirconia was further allotted into four groups based on the type of surface treatment method. The four groups were: control (C), air abrasion with 110 µm Al2O3 particles (A), etching with Zircos-E Etching solution for 2 hours (E), and a combination of air abrasion and etching (AE). After the surface treatment, all specimens were ultrasonically cleaned and 10 resin cement cylinders were attached to the zirconia discs in each group. A micro-shear bond strength test was performed in a universal testing machine at a crosshead speed of 0.5 mm/min. The fracture surfaces were assessed under a compound microscope. SEM, EDAX, and AFM analyses were done for the zirconia specimens after being subjected to surface treatment. Statistical analysis for the bond strength test was done using the Shapiro-Wilk test, one-way analysis of variance (ANOVA), and Post hoc Tukey test. Results: The micro-shear bond strength values for the groups were as follows in megapascals (MPa): OC 18.96 (5.54), OA 22.66 (2.51), OE 28.48 (4.50), OAE 28.63 (4.53), TC 22.82 (5.46), TA 25.36 (5.17), TE 28.12 (4.76), and TAE 32.00 (3.47). The one-way analysis of variance (ANOVA) and post hoc Tukey HSD tests were done which showed significant results in the groups. In opaque zirconia, significant differences were seen in the etching and air abrasion with etching groups when compared with the control and air abrasion groups. There was no difference between the etching and air abrasion with etching groups. For translucent zirconia, the only significant difference was seen in the air abrasion with etching group in comparison with the control and air abrasion groups. The mode of failure was majorly adhesive. The surface topography and surface roughness showed significant differences between the groups. The EDAX results showed material loss that occurred due to sandblasting in the air abrasion groups. Conclusions: Etching with Zircos-E Etching solution significantly increased the bond strength of zirconia to resin cement when compared with other surface treatment methods. In translucent zirconia, the best results can be achieved by combining etching with air abrasion.
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OBJECTIVES: This study aimed to evaluate the release of calcium ions from a bioactive restorative material and its shear bond strength (SBS) to primary dentin. STUDY DESIGN: Occlusal surface of extracted non-carious primary molars were flattened, onto which 2 × 2 mm cylinders of ACTIVA™ BioActive Restorative (PULPDENT® Corporation, Watertown MA) or Fuji II LC (GC Corporation, Tokyo, Japan) were prepared using a polypropylene straw mould. SBS of the materials to primary dentin was tested using a universal testing machine. The mode of bond failure was assessed using stereomicroscopy. 10 mm × 2 mm disks of each material were prepared and immersed in Milli-Q water for 1, 7, 14 and 21 days. The released calcium ions in the immersion media were quantified using Atomic Absorption Spectroscopy. RESULTS: ACTIVA™ BioActive Restorative showed a mean SBS of 4.29 ± 0.65 MPa to primary dentin and calcium ion release of 0.76 ± 0.12 ppm over 21 days. CONCLUSION: ACTIVA™ BioActive Restorative showed a significantly higher mean SBS to primary dentin, and significantly higher calcium ion release compared to Fuji II LC.
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Calcio , Recubrimiento Dental Adhesivo , Humanos , Resinas Compuestas/química , Recubrimiento Dental Adhesivo/métodos , Recubrimientos Dentinarios/química , Materiales Dentales/química , Cementos de Ionómero Vítreo/química , Dentina , Diente Primario , Ensayo de Materiales , Resistencia al Corte , Cementos de Resina/químicaRESUMEN
ABSTRACT Objective To evaluate and compare the effect of 17% Ethylenediaminetetraacetic Acid (EDTA), 9% Etidronic acid (HEDP), and 7% Maleic acid (MA) on the push-out bond strength of NeoMTA Plus sealer to the coronal, middle, and apical thirds of root canal dentin. Material and Methods Forty single-rooted human maxillary central incisors were selected and decoronated to 12 mm long root fragments. Working length was established and root canals were then enlarged up to rotary Protaper F3. After each instrumentation, the root canal was irrigated with 2.5% NaOCl. For the final irrigation regimen, the specimens were divided into 4 groups (n=10) and treated with EDTA, HEDP, MA or Saline. Root canals were coated with NeoMTA Plus sealer, and obturation was done with single cone obturation technique. Subsequently, three horizontal sections were taken from the coronal, middle and apical thirds of each specimen, and POBS was measured using a universal testing machine. The type of bond failures was assessed under a stereomicroscope. Statistical analysis was done with One-way ANOVA with Tukey's Post hoc analysis. Results MA and EDTA showed the highest POBS. There was no significant difference in bond strength between MA and EDTA (p>0.05). HEDP and Saline showed lower POBS. Among all the four groups, the coronal third showed the highest values, followed by middle and apical thirds. Conclusion The type of chelating agent used during the root canal treatment significantly affects the bond strength of NeoMTA Plus to the root canal dentin.
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Humanos , Materiales de Obturación del Conducto Radicular , Resistencia a la Tracción , Quelantes/química , Cementos Dentales , Endodoncia , Análisis de Varianza , Ácido Edético , Ácido Etidrónico , Materiales Dentales/química , Incisivo , India , Hidrazida MaleicaRESUMEN
BACKGROUND: There are conflicting results concerning the ideal time for etching primary dentin and its effect on the bond strength of adhesive restorative materials. AIM: To assess in vitro, the effect of varied acid concentration and etch time on the morphological features and tensile bond strength of primary dentin. MATERIALS AND METHODS: Forty healthy primary molars were prepared by exposing the dentin of the occlusal surface, creating a smear layer. A 3 mm × 3 mm test indow was demarcated, and specimens were randomly allocated to four groups (n = 10): Group 1A 10% phosphoric acid, 7 s; Group 1B 10% phosphoric acid, 15 s; Group 2A 37% phosphoric acid, 7 s and Group 2B 37% phosphoric acid, 15 s. Surface analysis was done using atomic force microscope and scanning electron microscope. For tensile bond strength evaluation, 24 specimens prepared as mentioned were mounted in acrylic blocks and allocated to four groups according to the prescribed etching protocol. Resin rods were bonded and tested in tension after 24 h (n = 6). Data were analyzed statistically using unpaired t-test. RESULTS: Etching of primary dentin using 37% phosphoric acid for 7 s produced the highest tensile bond strength of 9.51 ± 2.19 MPa. CONCLUSION: Etching time of 7 s may improve the adhesion of resin restorative materials with primary dentin.
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Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Grabado Ácido Dental , Resinas Compuestas , Dentina , Humanos , Ensayo de Materiales , Cementos de Resina , Propiedades de Superficie , Resistencia a la TracciónRESUMEN
OBJECTIVE: The study aimed to fabricate and test the biocompatibility of a polylactic-co-glycolic acid (PLGA) based guided tissue regeneration membrane impregnated with 'simvastatin' to promote sustained drug delivery near osseous defects and evaluate the regenerative potential of the membrane histologically. MATERIALS AND METHODS: We tested the mechanical properties and cytotoxicity of an indigenously fabricated PLGA membrane incorporated with simvastatin (1 mg/cm2). An animal study evaluated the regenerative potential of the membrane. Twenty-four adult Wistar rats, approximately 175 g in weight, were used in this study. The rats were divided randomly into four groups based on the postoperative healing periods into ten days, 1, 3, and 6 months. Within each time group, six rats were divided into three subgroups: Subgroup A - sham surgery controls; Subgroup B - PLGA without Simvastatin; Subgroup C - PLGA with simvastatin tests. The radiographic examination intervals were ten days, 1 and 3 months, while the histological assessment was around 1, 3, and 6 months. RESULTS: Simvastatin content was distributed uniformly in all the prepared membranes and was equivalent to 1 mg/cm2. 100 mg PLGA membrane with simvastatin demonstrated uniform drug release over time, excellent mechanical properties, and biocompatibility. The rat models in Subgroup C had better bone tissue formation radiographically and histologically. CONCLUSION: The study suggested that 'PLGA with Simvastatin' has the requisite properties to serve as a third-generation barrier membrane with the potential for local drug delivery.
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Polímeros , Simvastatina , Animales , Ratas , Regeneración Ósea , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Ratas Wistar , Simvastatina/farmacologíaRESUMEN
BACKGROUND: Polishing of dental composite restorations to achieve a highly smooth and reflective surface not only enhances esthetics but also their color stability and improves resistance to staining. The objective of this study was to evaluate the effect of beverages on the color stability of nanoceramic composites polished using different techniques. METHODS: 80 samples of ceram. X SphereTEC one were prepared by condensing the material into a stainless-steel split mold and divided randomly into two groups. Group I was subjected to polishing using Sof-Lex system™ disks, and Group II was kept unpolished. Each group was subdivided into four sub-groups of 10 samples each. Each subgroup samples were immersed into designated beverages (Tropicana orange juice, Coco-cola, Nescafe coffee, and distilled water) for a duration of 15mins/day for 15 days. The color of all specimens before immersion, one day, and 15 days after immersion was measured using a Spectrophotometer. RESULTS: Significant staining of the material was found with cola drinks and coffee compared to orange juice and distilled water. Polished material showed better resistance to staining by various beverages compared to control group. CONCLUSION: Nanoceramic composites exhibited superior color stability after polishing with Sof-Lex system™. Among the beverages, coco-cola significantly altered the color of the composite.
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INTRODUCTION: Glass ionomer cements (GICs) are commonly used for cementation of indirect restorations. However, one of their main drawbacks is their inferior mechanical properties. AIM: Compositional modification of conventional glass ionomer luting cements by incorporating two types of all-ceramic powders in varying concentrations and evaluation of their film thickness, setting time, and strength. Material & Methods. Experimental GICs were prepared by adding different concentrations of two all-ceramic powders (5%, 10, and 15% by weight) to the powder of the glass ionomer luting cements, and their setting time, film thickness, and compressive strength were determined. The Differential Scanning Calorimetry analysis was done to evaluate the kinetics of the setting reaction of the samples. The average particle size of the all-ceramic and glass ionomer powders was determined with the help of a particle size analyzer. RESULTS: A significant increase in strength was observed in experimental GICs containing 10% all-ceramic powders. The experimental GICs with 5% all-ceramic powders showed no improvement in strength, whereas those containing 15% all-ceramic powders exhibited a marked decrease in strength. Setting time of all experimental GICs progressively increased with increasing concentration of all-ceramic powders. Film thickness of all experimental GICs was much higher than the recommended value for clinical application. CONCLUSION: 10% concentration of the two all-ceramic powders can be regarded as the optimal concentration for enhancing the glass ionomer luting cements' strength. There was a significant increase in the setting time at this concentration, but it was within the limit specified by ISO 9917-1:2007 specifications for powder/liquid acid-base dental cements. Reducing the particle size of the all-ceramic powders may help in decreasing the film thickness, which is an essential parameter for the clinical performance of any luting cement.
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OBJECTIVE: The quest for ideal pulp capping materials has given rise to the development of newer materials such as light cure mineral trioxide aggregate (MTA). The bond strength of the pulp capping materials with overlying restoration is one among the several factors that are critical for the success of vital pulp therapy. Hence, we conducted this study to evaluate and compare the shear bond strength (SBS) of light cure MTA and light cure calcium hydroxide with nanofilled composite. MATERIALS AND METHODS: Thirty acrylic blocks each with a central hole were prepared to uniform dimensions and randomly distributed into two equal groups. In Group I, light cure MTA, and in Group II, light cure calcium hydroxide was used as pulp capping materials. After the application of adhesive system, nanofilled composites were applied onto the pulp capping material using a cylindrical plastic matrix. The SBS was tested on a universal testing machine (Instrom 3366, UK) at a crosshead speed of 0.5 mm/min. The samples were examined under stereomicroscope and scanning electron microscope to analyze different modes of failure. RESULTS: The results were statistically analyzed using independent sample t-test. Light cure MTA attained the mean SBS of 6.54 MPa and light cure calcium hydroxide attained the mean SBS of 6.56 MPa. There was no significant difference statistically in SBS of both the materials (P < 0.05). The modes of failure were predominantly mixed failure followed by cohesive failure within the restorative material in both Group I and II. CONCLUSION: The results of the study suggest that the SBS of light cure MTA and light cure calcium hydroxide is comparable. The modes of failure analyzed in both light cure MTA and light cure calcium hydroxide are not significantly different statistically. Hence, both materials can be successfully used as pulp capping material with nanofilled composite.
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Hidróxido de Calcio , Recubrimiento Dental Adhesivo , Compuestos de Aluminio , Compuestos de Calcio , Resinas Compuestas , Recubrimiento de la Pulpa Dental , Combinación de Medicamentos , Microscopía Electrónica de Rastreo , Óxidos , SilicatosRESUMEN
BACKGROUND: Composites are in great demand due to the esthetic needs of the patients, which explains a wide variation in the types of available composites. However, the mechanical strength of the materials is questionable. Therefore, the mechanical properties of the newly available bulk-fill composites have been tested. OBJECTIVES: The main objective of the study was to compare the depth of cure (DOC) and surface roughness of 3 different bulk-fill composites: X-tra fil® (XTF), Tetric EvoCeram® Bulk Fill (TEC) and Beautifil® Bulk Restorative (BBR). MATERIAL AND METHODS: Fifty-seven (n = 19 in each group) samples were made using brass molds. All samples were subjected to Vickers hardness testing and profilometry. The one-way analysis of variance (ANOVA) test was used for the data analysis, followed by Tukey's post hoc test. RESULTS: The differences in the mean surface microhardness values of the materials were statistically significant (p < 0.001), with XTF showing the highest value. The TEC composite showed a higher surface roughness as compared to BBR and XTF. CONCLUSIONS: The results of the present study indicate that variations in the filler size and amount significantly influence the DOC and surface roughness of dental composites. Among the tested composites, the multi-hybrid composite exhibited superior DOC (XTF), whereas the nanohybrid composite exhibited superior surface finish (TEC).
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Resinas Compuestas , Estética Dental , Materiales Dentales , Dureza , Humanos , Ensayo de MaterialesRESUMEN
AIM AND OBJECTIVES: In dentistry, base metal casting alloys are extensively used for the fabrication of inlays, onlays, crowns, bridges, partial dentures, etc. During the casting of these alloys, excess amount of material used than needed will be collected as sprue buttons at the end, which is either added to the fresh alloy during casting and reused or disposed of. MATERIALS AND METHODS: The aim of the present in vitro experimental study was to investigate the effect of the complete recasting of four commercially available cobalt-chromium (Co-Cr) and nickel-chromium (Ni-Cr) base metal casting alloys on their cytotoxicity. During the study, four groups of alloys were subjected to complete recasting up to twenty times without the addition of new alloy. The cytotoxicity assessment of the selected alloys after recasting (Co-Cr and Ni-Cr alloys) was carried out using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. RESULTS: The results indicated that Co-Cr alloys exhibit superior cell viability compared to Ni-Cr alloys, and cytotoxic potential of the alloys increased with repeated casting and led to increased cell death. The recasting of alloys in the present study did not show high cytotoxicity even after the 20th recasting. CONCLUSION: From the results of the present study, it can be concluded that the alloys generated as a waste in the dental laboratory can be safely reused up to five times or at least once before they can be disposed, which reduces the cost of the treatment and also helps in conserving the natural resources.