Influence of impression materials and techniques, times and pouring materials in dimensional accuracy of total casts

• Grant number: 15/12387-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2016
• End date: May 31, 2019
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: José Maurício dos Santos Nunes Reis
• Grantee: Aion Mangino Messias
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

This study will analyze the accuracy of dental casts made from different impression materials and techniques, and poured in diverse times and with different gypsums. Measurements of marginal fit of yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) frameworks on crown preparations will be also evaluated. A master model with crown preparations in the teeth 14, 16, 21 and 25 will be used to manufacture zirconia frameworks. Three impression techniques will be used: (T1) simultaneous, (T2) two step - relief with a film of polyvinyl chloride (PVC) and (T3) digital impression (Cerec Conect Omnicam - Sirona). For the impressions made with condensation silicone (Speedex - Coltène Whaledent Inc.) the molds will be poured in 30 minutes, 3 or 7 days. For the impressions made with vinyl polysiloxane (Express XT - 3M ESPE), casts will be obtained after 2 hours, 3, 7 or 15 days. Conventional casts will be poured by a single calibrated operator with two type IV gypsums (GC Fuji Rock EP - GC America or Zero Stone - Dentona AG). For each experimental condition full impressions (n=8) will be obtained with stock metal tray. For the 3D dimensional analyzes, the casts from T1 and T2 will be scanned with an optical digitizer (R700 - 3ShapeA/S) and compared with those digital images acquired from T3, by virtual images analyzes made by 3D image analyzer softwares (VistaDent" 3D - Dentsply and 3DS Max - Autodesk® Inc.). A stereomicroscope LEICA (50x) will be used to measure the marginal misfit of the zirconia frameworks. The data will be analyzed regarding the sample number and its statistically significant power. Based on normality and homoscedasticity tests, statistical methods will be applied to evaluate the influence of the independent variables of the study, with a significance level of 5%.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

MESSIAS, Aion Mangino. Influence of impression techniques and impression materials, pouring time and casting materials in three-dimensional accuracy of gypsum casts. 2019. Doctoral Thesis - Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araraquara Araraquara.