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1.
Indian J Dent Res ; 31(4): 537-545, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33107453

RESUMEN

Purpose of the Study: To comparatively evaluate the wear resistance of two different posterior indirect restorative materials against human enamel. Materials and Methods: Two different posterior indirect restorative materials of ten in each Group-I (Monolithic zirconia) (n = 10) and Group-II (Cast cobalt chromium) (n = 10) were formed into disc and used as a substrate for the wear test. Freshly extracted mandibular first premolars were used as a pin (antagonist) (n = 20). Pin-on-disc wear testing machine was used to simulate the masticatory parameters and evaluation of the wear parameters was done after 1,20,000 cycles, with load of 40N for specific duration. Data related to wear testing procedure were tabulated and evaluated. Results were statistically analyzed using Mann-Whitney test and Wilcoxon signed rank test. Results: Mean surface roughness value (Ra value) obtained for Group-I disc test samples showed no statistical significance (P value < 0.05). Mean wear rate value of test disc samples was statistically significant between Group-I and Group-II (P value < 0.05). Mean surface roughness value was statistically significant between Groups-I and II before and after wear test (P value < 0.05). Conclusion: From the results obtained, it was found that the Group-I (Monolithic zirconia) exhibited higher wear resistance than Group-II (cast cobalt chromium) and causes less wear to the opposing enamel antagonist.


Asunto(s)
Aleaciones de Cromo , Porcelana Dental , Diseño Asistido por Computadora , Esmalte Dental , Humanos , Ensayo de Materiales , Propiedades de Superficie , Circonio
2.
Implant Dent ; 28(3): 289-295, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31124826

RESUMEN

PURPOSE: The purpose of this study was to evaluate the fit of nonoriginal abutments to implants at the implant abutment junction. MATERIALS AND METHODS: Twenty titanium implants from a single manufacturer were randomly divided into 2 groups of ten each. Ten titanium premachined original abutments (group I) and ten titanium premachined nonoriginal abutments (from different manufacturer-group II) were connected to the implants with the recommended manufacturer torque level and then embedded into autopolymerizing clear acrylic resin blocks. After overnight curing, these blocks were vertically sectioned using water jet sectioning machine and evaluated under scanning electron microscope following the sequential cleaning procedures. The microgap at the implant-abutment interface for all the samples was measured using pixel counting software and subjected to statistical analysis using nonparametric Mann-Whitney U test. RESULTS: The mean microgap at the implant-abutment interface at the external, middle, and internal points was 1.597, 1.399, and 1.831 µm, respectively, for group I and 2.395, 2.488, and 3.339 µm, respectively, for group II samples. Nonparametric Mann-Whitney U test showed statistically significant difference between 2 groups at the midpoint for the nonoriginal abutments compared with the original ones. CONCLUSION: Within the limitations of the study, the mean microgap at the implant-abutment interface at the platform level at the external, middle, and internal points for both original abutments and nonoriginal abutments was found to be within clinically acceptable limits.


Asunto(s)
Pilares Dentales , Implantes Dentales , Diseño de Implante Dental-Pilar , Ensayo de Materiales , Propiedades de Superficie , Titanio , Torque
3.
Contemp Clin Dent ; 10(1): 56-63, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-32015643

RESUMEN

Purpose: The purpose of this in vitro study was to comparatively evaluate the masking ability of lithium disilicate ceramic with different core thickness on the shade match of indirect restorations over metallic substrate. Materials and Methods: A total of 30 heat pressed lithium disilicate ceramic discs of low translucency were fabricated with diameter 10mm and thickness of 1 mm, 1.3 mm and 1.6mm with each thickness consisting of 10 samples to be used in the study. Thirty Ni-Cr metal discs of diameter 10mm were used to simulate metallic substrates .The colour difference of the lithium disilicate ceramic disc before and after cementation were measured using CIE LAB system. Results: The mean colour difference (ΔE) of Group I,Group II, Group III before cementation with the Ni-Cr metal discs was 17.32,13.01 and 11.73 respectively. The mean colour difference (ΔE) of Group I,Group II, Group III after cementation with the Ni-Cr metal discs was 16.32,12.10, 11.05 respectively. Conclusion: The mean colour difference of the three groups were found to be more than the clinically acceptable perceptibility threshold (ΔE < 3.3) indicative of reduced masking ability of all the three groups of ceramic discs over metallic substrate used in this study.

4.
J Prosthodont ; 27(5): 469-475, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27385390

RESUMEN

PURPOSE: To comparatively evaluate the antimicrobial efficacy of freshly prepared electrolyzed oxidizing water (EOW) with that of 2.4% glutaraldehyde (GA) and 1% sodium hypochlorite (SH) on clinically derived poly vinyl siloxane (PVS) impressions. MATERIALS AND METHODS: Four clinically derived PVS impressions each were obtained from 10 subjects. One impression from each subject was randomly kept as control (group I), without disinfection. The remaining three impressions were randomly disinfected by immersion in either 2.4% GA (group II), 1% SH (group III), or freshly prepared EOW (group IV). The samples were subjected to microbial culture individually on brain heart infusion (BHI) agar medium. The organisms isolated were confirmed by visual examination and gram staining. Mean colony forming units (CFU) were counted, log10 reduction obtained and compared. Data were statistically analyzed using one-way ANOVA, followed by multiple comparisons using Tukey-HSD post hoc tests (p < 0.05). RESULTS: Streptococci, Staphylococci, Pseudomonas, Candida, Proteus, Klebsiella, and E. coli were isolated from all impressions including the controls, except those disinfected by EOW. All three disinfectants showed significant reduction in CFU and log10 reduction values as compared to the controls. EOW showed significantly higher reduction in log10 values compared to GA and SH, whereas GA and SH showed similar reductions. EOW, GA, and SH showed kill rates of 100%, 99.60%, and 99.82%, respectively. CONCLUSION: EOW showed significant antimicrobial efficacy as evidenced by reduction in log10 values when used as an immersion disinfectant for PVS impressions when compared with the results obtained using GA and SH. These results need further investigation. CLINICAL IMPLICATIONS: EOW shows high antimicrobial efficacy when used as an immersion disinfectant as compared to GA and SH for clinically derived PVS impressions.


Asunto(s)
Antibacterianos/química , Antiinfecciosos/química , Desinfectantes Dentales/química , Materiales de Impresión Dental/química , Desinfección/métodos , Contaminación de Equipos/prevención & control , Glutaral/química , Polivinilos/química , Siloxanos/química , Hipoclorito de Sodio/química , Adulto , Recuento de Colonia Microbiana , Técnica de Impresión Dental , Femenino , Humanos , Masculino , Persona de Mediana Edad , Propiedades de Superficie
5.
J Pharm Bioallied Sci ; 7(Suppl 2): S794-6, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26538972

RESUMEN

Esthetic demands have considerably increased over the years in routine clinical practice. A pleasant smile can give supreme confidence to an individuals personality. However, a perfect smile is dictated by a perfect balance of the white (teeth) and pink (gingival) display. This balance can be managed different treatment modalities, which is based on proper diagnosis. This case report demonstrates a successful management of gummy smile with a lip-repositioning procedure in a patient with an incompetent upper lip. This was accomplished by removing a partial thickness strip of mucosa from the maxillary buccal vestibule and suturing the lip mucosa to the mucogingival line. This resulted in a narrower vestibule and restricted muscle pull, thereby resulting incompetent lips and reduced gingival display during smiling.

6.
J Clin Diagn Res ; 9(9): ZC16-21, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26501005

RESUMEN

BACKGROUND: Debonding of artificial teeth from the denture base is an important issue for edentulous patients rehabilitated with conventional or implant supported complete dentures. AIM: The purpose of this study was to evaluate shear bond strength between denture base resin and acrylic resin denture teeth subjected to three different surface modifications on the ridge lap area as compared to unmodified denture teeth. MATERIALS AND METHODS: Forty acrylic resin central incisor denture teeth were selected and randomly divided into four test groups. The teeth in each group were subjected to one of the three different surface modifications, namely, chemical treatment, sandblasting and placement of retentive grooves on the ridge lap area respectively, prior to packing of the denture base resin. The group with unmodified teeth served as control. Forty acrylic resin test blocks thus obtained were tested for shear bond strength between acrylic resin teeth and denture base resin in Universal Testing Machine. Data obtained was statistically analysed using one-way ANOVA and Student- Newman- Keul's test (p< 0.05). RESULTS: Analysis of shear bond strength revealed that retentive grooves on the ridge lap area showed highest bond strength values followed by sandblasting and both were statistically significant compared to the control and chemically treated groups. Unmodified surface of the resin teeth showed the least bond strength. CONCLUSION: Within the limitations of this invitro study the placement of retentive grooves or sandblasting of the ridge lap area showed highly significant improvement in shear bond strength compared to the unmodified surface. Chemical treatment did not result in any significant improvement in the shear bond strength compared to the unmodified surface.

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