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1.
J Contemp Dent Pract ; 21(7): 792-797, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33020365

RESUMEN

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.


Asunto(s)
Caries Dental/prevención & control , Diente , Esmalte Dental , Humanos , Remineralización Dental
2.
Indian J Dent Res ; 31(3): 470-474, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32769285

RESUMEN

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.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Cerámica , Cementos Dentales , Porcelana Dental , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Resistencia al Corte , Propiedades de Superficie
3.
J Contemp Dent Pract ; 18(6): 484-489, 2017 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-28621279

RESUMEN

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.


Asunto(s)
Análisis del Estrés Dental , Gutapercha , Materiales de Obturación del Conducto Radicular , Preparación del Conducto Radicular/instrumentación , Análisis de Elementos Finitos , Humanos , Ensayo de Materiales , Modelos Teóricos , Retratamiento , Torsión Mecánica
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