Renato Morales Jóias

Shear bond strength of a ceramic to Co-Cr alloys

STATEMENT OF PROBLEM Different combinations of Co-Cr alloys bonded to ceramic have been used in dentistry; however, the bond strength of ceramic to metal can vary because of different compositions of these alloys. PURPOSE The purpose of this study was to evaluate the shear bond strength of a dental ceramic to 5 commercially available Co-Cr alloys. MATERIAL AND METHODS Five Co-Cr alloys (IPS d.SIGN 20, IPS d.SIGN 30, Remanium 2000, Heranium P, and Wirobond C) were tested and compared to a control group of an Au-Pd alloy (Olympia). Specimen disks, 5 mm high and 4 mm in diameter, were fabricated with the lost-wax technique. Sixty specimens were prepared using opaque and dentin ceramics (VITA Omega 900), veneered, 4 mm high and 4 mm in diameter, over the metal specimens (n=10). The shear bond strength test was performed in a universal testing machine with a crosshead speed of 0.5 mm/min. After shear bond testing, fracture surfaces were evaluated in a stereomicroscope under x25 magnification. Ultimate shear bond strength (MPa) data were analyzed with 1-way ANOVA and the Tukey HSD test (alpha =.05). RESULTS The mean (SD) bond strengths (MPa) were: 61.4 (7.8) for Olympia; 94.0 (18.9) for IPS 20; 96.8 (10.2) for IPS 30; 75.1 (12.4) for Remanium; 71.2 (14.3) for Heranium P; and 63.2 (10.9) for Wirobond C. Mean bond strengths for IPS 20 and IPS 30 were not significantly different, but were significantly (P<.001) higher than mean bond strengths for the other 4 alloys, which were not significantly different from each other. CONCLUSIONS Bond strength of a dental ceramic to a Co-Cr alloy is dependent on the alloy composition.

General and oral characteristics of Rett syndrome: case report

Introduction: Rett syndrome is a neurodegenerative disease that affects females of all races worldwide. It is the second most frequent cause of mental disability in girls. Objective: To describe the general and oral characteristics at stage three. Case report: A girl aged seven years and seven months, leukoderma, coming from Vallo della Lucania, Salerno, Italy was at the stage three of Rett syndrome. At the first stage, from six to eighteen months of life, the girl ate by herself, but she did not walk. At the second stage, from eighteen months of life, she started the ataxic gait and stopped talking. At the third stage, she had the reduction of the autist behavior, improved the eye contact, smile and communicative abilities. The genetic examination revealed de novo mutation, that is, without inheritance. Conclusion: Rett syndrome lacks specific treatment. Adjuvant therapies include physiotherapy, hydrotherapy, occupational therapy, music therapy, equine therapy, as well as therapies to treat some symptoms. A multidisciplinary treatment is required. The prognosis consists of following-up the individual throughout life, treating the symptoms. Keywords: Autistic Disorder, Chronic disease, Epilepsy, Intellectual Disability, Rett Syndrome.