Effect of different manipulations on the physical, chemical and microstructural characteristics of Biodentine.

OBJECTIVE: The water to powder ratio and method of mixing is important for the properties of hydraulic cements. For this purpose a number of clinicians prefer premixed materials. Dental manufacturing companies provide predosed materials, however the manufacturer instructions are not always adhered to. The aim of this research is to investigate physical and chemical alterations of the tricalcium silicate-based cement Biodentine when manipulated according to the manufacturer's instructions (control) or changing the doses and mixing of the material components. METHODS: 6 groups were constituted according to different mixing and dosing of powder and liquid. The hydrated cements were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Calcium ion concentration of the leachate was also investigated. Assessment of the physical characteristics included setting time and microhardness. RESULTS: Microstructural differences were visible only in the Biodentine mixed manually with water, in which early hydration rate was also affected, with lower calcium ion release. Increase of Biodentine liquid increased the calcium ion release, but also increased the setting time. Manual manipulation required more liquid (both water and Biodentine liquid) added to the mixture to guarantee a similar consistency to the control. A decrease in setting time was also noted. All groups showed higher values of microhardness at 24 h compared to the freshly set materials. In the freshly set materials, there was an overall decrease in microhardness in all groups when compared to group control, particularly significant when increasing the dosage of Biodentine liquid. SIGNIFICANCE: When mixing Biodentine, altering the mixing procedure in terms of type and amount of liquid added to the powder and mixing device chosen has an effect on the physical, chemical and mechanical characteristics and surface topography of the material, when compared to Biodentine mixed according to the manufacturer's recommendations. Hence, the manufacturer's instructions should be strictly followed.

Management of a perforating internal root resorption using mineral trioxide aggregate: a case report with 5-year follow-up.

Internal root resorption is characterised by progressive loss of tooth substance initiating at the root canal wall as a result of clastic activity. This report describes a case of a perforating internal root resorption on a maxillary central incisor in a 25-year-old patient. The perforating internal root resorption was firstly diagnosed with periapical radiographs and assessed with full detail with the aid of CBCT, allowing determination of the extension and areas involved in the resorption lesion, as well as the treatment planning. According to these findings, a MTA barrier was performed on the root, -coronally to the resorption lesion, leaving the root apically to the resorption lesion untouched. Clinical findings and periapical radiographs indicated complete resolution of the radiolucency associated with the resorptive defect, with reestablishment of lamina dura along the root and occlusion of the lumen of the root canal in the apical segment, after a 5-year follow-up.