Investigation of the effect of the water to powder ratio on hydraulic cement properties

Abstract

Objectives. The use of rheological properties to determine the optimal water: powder ratio of tricalcium silicate-based prototype materials incorporating alternative radiopacifiers and fillers. Determination of how the proportion of water incorporated affected the physicochemical behaviour of the materials. Methods. Endodontic cements replaced with 30% radio-opacifier, and additions of calcium phosphate and micro-silica were tested. The unmodified cements were mixed with a 0.35 water: powder ratio which served as control. At this water: powder ratio, the paste had an adequate clinical consistency and furthermore these pastes have been well characterized. Assessment of material rheological properties enabled adjustment of the water: powder ratio in each material to provide comparable viscosity values to those of the controls. The flowability, phase analysis and calcium release were measured for both viscosity-matched and the standard 0.35 water: powder ratio blends. The prototype materials with the adjusted water ratio were also characterized by scanning electron microscopy, energydispersive spectroscopy and evaluated for radio-opacity. Results. The use of the 0.35 water: powder ratio is not appropriate when changing the radiopacifier and incorporating additives. Zirconium oxide did not vary the water: powder ratio but tantalum oxide and calcium tungstate resulted in an increase and decrease in water demand respectively. Using the standard 0.35 ratio when the mixture had a low water demand resulted in higher flowability values and calcium release in solution. Micro-silica and calcium phosphate altered the hydration of the materials. All materials were adequately radiopaque.

Effect of the addition of nanoparticles of CaCO3 and different water‐to‐powder ratios on the physicochemical properties of white Portland cement

“…In addition, WPC has a different manufacturing process, especially as it relates to cooling and milling procedures (Hamad, 1995; Kirchheim, Rheinheimer, & Dal Molin, 2015). The authors of the present study opted for using other specifications (ISO 6876:2012 and No.57 of ANSI/ADA) to assess the WPC properties, instead of the ASTM C150 specification, as specimens of smaller dimensions were used to perform the tests, being in accordance with previous studies (Bernardi et al, 2017; Koutroulis et al, 2019; Tanomaru‐Filho et al, 2015) that tested PC in order to develop a cement for endodontic proposal.…”

“…The development of cements for use in Dentistry seeks to obtain a material that presents desirable physicochemical, mechanical, and biological properties for clinical use, in addition to a reasonable cost (Koutroulis, Batchelor, Kuehne, Cooper, & Camilleri, 2019). Calcium silicate‐based cements are moisture‐hardening composites, which belong to a class of materials called hydraulic binders (Kogan, He, Glickman, & Watanabe, 2006).…”

Histomorphometric and immunohistochemical study shows that tricalcium silicate cement associated with zirconium oxide or niobium oxide is a promising material in the periodontal tissue repair of rat molars with perforated pulp chamber floors

“…Moreover, the material containing ZrO 2 reduced tissue damage when compared with bismuth oxide (Silva et al 2014). According to Koutroulis et al (2019), the addition of 30% ZrO 2 to the tricalcium silicate cement did not alter the flowability of tricalcium silicate and resulted in a material with radiopacity above the minimum value recommended by ISO 6876. ZrO 2 is present as a radiopacifier agent in some endodontic materials such as Biodentine [( Septodont (Karlinsey et al 2006), this radiopacifying agent has been used in experimental endodontic materials , Bosso-Martelo et al 2016, Mesteiri et al 2017).…”

Classification of Hydraulic Cements Used in Dentistry

“…However, whether they actually improve strength or hardness is unclear; this would not be expected (50). Reaction modifiers such as fumed silica and calcium carbonate could also be considered as mechanical modifiers, but this is only proper when the watercement ratio is controlled (51,52).…”