Background: Marginal adaptation is very important in cast restorations. Maladaptation leads to plaque retention, reduction of mechanical and esthetic properties. The aim of this study was to evaluate the precision of three different impression materials (including: Additional silicone [AS] and condensational silicone [CS] and polyether [PE]) for duplicating master dies.
Materials And Methods: Three master dies from an acrylic tooth model-with supragingival and shoulder finishing line was made by using PE: Impergum, CS: Speedex, and AS: Panasil separately. The Ni-Cr copings were prepared from master dies separately. They were placed on the acrylic model and the mean marginal difference was recorded by using a stereomicroscope. Then 30 duplicate test dies were made by using the same impression materials and the marginal gaps were recorded. The comparison was done by one-way ANOVA and SPSS software (Version 13) at a significant level of 0.05.
Results: The mean marginal difference of four walls from Impergum (38.56 um) was the lowest than Speedex (38.92 um) and Panasil (38.24 um). The Impergum had the highest capability in making duplicate dies (P > 0.05).
Conclusion: The Impergum impression material manifested the highest capability in making a better marginal adaptation of duplicate dies but further studies are needed to make a precise decision.
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BMC Oral Health
January 2025
Faculty of Dentistry, British University in Egypt (BUE), Shorouk, Egypt.
Purpose: This study aimed to compare different treatment modalities to correct ill-fitted maxillary complete denture either by the conventional relining method or by scanning the relining impression and digitally construct a new denture regarding patient satisfaction, denture retention, and adaptation.
Materials And Methods: Twelve edentulous patients suffering from loose maxillary complete dentures were selected, dentures' borders and fitting surfaces were prepared, and relining impressions were taken, the impressions were scanned and the STL files were used for CAD/CAM milling ( computer aided designing/ computer aided manufacturing) of new maxillary dentures (Group A), then the relining impression went through the conventional laboratory steps to fabricate (Group B) maxillary dentures. Both groups were evaluated regarding patient satisfaction by a specially designed questionnaire, retention values were measured by a digital force gauge at denture insertion appointment and two weeks later, geomagic software was used to evaluate dentures adaptation to oral tissues.
Diagn Cytopathol
January 2025
Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, USA.
Background: Endobronchial ultrasound guided Transbronchial Needle Aspiration (EBUS-TBNA) is the predominant method for investigation of centrally located solitary pulmonary nodules. The method is associated with good to excellent diagnostic sensitivity and specificity with the positive predictive value of the test reaching 100% and reported negative predictive values for FNA of pulmonary nodules ranging from 53% to 97%. The impact of correlating cytologic results with imaging and clinical findings for improvement of negative predictive value has been poorly studied.
View Article and Find Full Text PDFImaging Sci Dent
December 2024
Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea.
Purpose: The study was performed to examine the error associated with image superimposition when computed tomography (CT) images of the dental region are substituted with dental scan data, according to the block-out material used in dental impressions.
Materials And Methods: A typodont model was created by bonding orthodontic brackets to teeth on plaster dental stones using melted dental base-plate wax. In the experiment, 2 groups were compared: one using wax and the other using putty as the block-out material to prevent tearing of the impression material during the acquisition of dental impressions.
BMC Oral Health
December 2024
Faculty of Odonto-Stomatology, University of Health Sciences, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam.
Background: The success of a restoration largely depends on the quality of its fit. This study aimed to investigate the fit quality of monolithic zirconia veneers (MZVs) produced through traditional and digital workflows.
Methods: A typodont maxillary right central incisor was prepared.
J Funct Biomater
December 2024
Centre for Oral Rehabilitation, Linköping, County Council of Östergötland, 581 86 Linköping, Sweden.
Objective: This study aimed to assess and compare the internal fit of custom-made posts and cores fabricated using digital impressions (DI) and conventional vinyl polysiloxane (VPS) impressions in restorative dentistry.
Materials And Methods: A typodont tooth model, simulating the anatomy of the root canal of a central incisor, was utilized for the study. Two groups were formed, Group A and Group B, and each group provided a total of 18 impressions of two types: DIs and VPS impressions.
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