A novel simplified method for assessing crystal length and crystalline content in dental ceramics.

The purpose of this study was to introduce a novel and simple method of evaluating the crystal length and crystalline content of lithium disilicate dental ceramics using images obtained from scanning electron microscopy (SEM) and analyzed with ImageJ (NIH) processing software. Three evaluators with varying experience levels assessed the average crystal length and percentage of crystalline content in four commercial lithium disilicate reinforced glass ceramic materials: IPS e.max (Ivoclar Vivadent), Rosetta SM (Hass), T-Lithium (Talmax), and IRIS CAD (Tianjin). The specimens, prepared from partially crystallized CAD/CAM blocks (3.0 mm3), were fully crystallized and treated with 5% hydrofluoric acid for 20 s prior to SEM analysis. After acquiring the SEM images, ImageJ software was used to evaluate the average crystal length and crystalline content on the surface of the different ceramics. An inter-operator agreement was observed (ICC/p = 0.724), indicating that assessments by the various operators were similar across all ceramic materials tested (p < 0.001). When crystal length and crystalline content were compared, IRIS CAD exhibited significant differences compared to the other materials (p < 0.001), showing a less dense crystalline matrix based on the average length of crystals and the percentage of crystals per unit area. The use of this software facilitated the evaluation of crystalline content and average crystal lengths in dental ceramics using SEM images, and demonstrated very low variability among different operators. RESEARCH HIGHLIGHTS: The described method, using ImageJ open-source software, provides precise and reliable measurements of crystal length and crystalline content in lithium disilicate ceramics, with high inter-operator agreement. The proposed method identified higher crystalline content in IPS e.max CAD compared to Rosetta SM CAD and T-lithium CAD ceramics, while IRIS CAD exhibited significantly lower crystalline content and larger average crystal length. The novel, simplified method for assessing crystal length and crystalline content presented in this study may also be useful for evaluating other dental ceramics.

Restoration of Anterior Dental Erosion with a Combination of Veneers and Crowns: A 3-Year Case Report.

This report describes the conservative management of a 40-year-old female patient with smooth, eroded facial enamel affecting her maxillary anterior and some posterior teeth. Using conventional enamel bonding, pressed leucite-reinforced laminate veneers were used to restore the length, contour, and esthetics of the maxillary right canine, as well as of the right lateral and both central incisors; at the same time, it was necessary to restore the maxillary left lateral incisor, canine, and first premolar of the same quadrant with all-ceramic crowns of the same material. The patient has been followed for 3 years and demonstrates a good esthetic outcome with no shade discrepancy between the two types of restoration. Apparently, the tooth structure, though eroded, was able to provide an adequate bonding substrate for these adhesive restorations.

Two-year clinical performance of Class V resin-modified glass-lonomer and resin composite restorations.

While a one-year report had been previously published, this study was undertaken to evaluate the clinical performance and appearance of a resin-modified glass ionomer and a resin composite over two years. Thirty-seven pairs of restorations of FujI II LC and Z 250/Single Bond were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. Restorations were clinically evaluated at baseline, 6, 12, 18 and 24 months using modified Ryge/USPHS criteria. No statistically significant difference (p = 0.13) was observed in the overall performance of the materials. Retention was 96% for the resin-modified glass ionomer and 81% for the resin composite, with no additional restorations of either material lost after one year. As previously reported, retention of the Z 250 restorations at six months was below the minimum specified in the ADA Acceptance Program for Dentin and Enamel Adhesives. The resin composite restorations generally had a better appearance, with a 100% alpha rating in color match, versus 85% for the resin-modified glass ionomer.

Amalgama Dental: revisión de la Literatura y Estado Actual / Dental Amalgam: literature review and current concepts

Este artículo presenta el desarrollo de las aleaciones modernas de amalgama, su comportamiento clínico de acuerdo a su composición y su forma física y la apropiada manipulación de estos materiales. Se concluye con una breve discusión de las restauraciones adhesivas de amalgama, y una observación acerca del potencial tóxico de mercurio en la amalgama