Effects of disinfectant solutions incorporated in dental stone on setting expansion, compression and flexural strength of dental models

Abstract

Purpose of the study: The aim of the study is to analyze the way the disinfectants embedded in the plaster affect the setting linear dimensional stability, flexural and compressive strength of dental stone models. Material and Methods: Samples were made of type IV dental stone in which different disinfectants had been incorporated (sodium hypochlorite 1%, chlorhexidine 2%) in two concentrations (50%, 100%), thus obtaining four test groups. Mentioned parameters are measured using a micro comparison device and an universal testing machine, analyzing statistically the results in comparison with the control group, prepared by standard indications. Results: Disinfectants cause a decrease of the setting expansion value (ΔL) compared to the standard group in all type of mixing percentage. Variations of compressive and flexural strength are statistically significant, particularly when adding 100% of hypochlorite 1%. Conclusions: Within the limits of this study, replacing the distilled water with disinfectants, alter the value of setting expansion and cause the model dental stone to be brittle in compression and bending.

Determination of Surface Roughness and Accuracy of Alginate Impression Material Disinfected by Immersion

“…1-Impressions were immersed in ethanol 70% for 3 minutes 2-Impressions were immersed in povidone-iodine 4% for 3 minutes A rectangular silicon mold measuring (521 cm) was used (14) . Figure (1) A round disk-shaped silicon mold measuring (4mm H, 6 mm W) is used for the dimensional accuracy test (3) .Figure (2).Following the water-powder ratio (18gm / 36 ml) recommended by manufacturer instructions After applying the alginate to the impression mold, a glass slab was placed over the alginate material to ensure the accurate contact of alginate with the mold and a uniform flat surface (15) . All of the alginate specimens were allowed to sit for five minutes at 37 Cᴼ.…”

“…Table (1) presents the descriptive statistics and figure (7) for the alcohol and povidone iodine groups. The mean values of alcohol specimens were decreased after immersion while increased in a povidoneiodine group after immersion.…”

“…Alginate impression is one of the highly contaminated materials between dental laboratory workers and patients. Infectious agents are transferred from saliva and blood to the casts via dental impression (1,2) . It has been found that 67% of dental material forward from a dental clinic to the lab is contaminated (3) .…”

The Effect of Different Additives on the Hydration and Gelation Properties of Composite Dental Gypsum

“…As an essential auxiliary material, dental gypsum has been used for simulating oral cavity models. Put a certain amount of dental gypsum powder and water in a small rubber bowl to knead the gypsum slurry and then cast the slurry into the oral mold to prepare dental restoration, such as an inlay, a crown, a bridge, a partial denture, and a complete denture [2][3][4]. The manufacture of denture model is the basis of denture processing, and the dimensional stability of gypsum is fundamental to achieving a precise fit between dental structure and restorative material [5,6].…”