The evaluation of microleakage and bond strength of a silicone-based resilient liner following denture base surface pretreatment

STATEMENT OF PROBLEM: The failure of adhesion between a silicone-based resilient liner and a denture base is a significant clinical problem. PURPOSE: The purpose of this study was to examine the effects of denture base resin surface pretreatments with different chemical etchants preceding the silicone-based resilient liner application on microleakage and bond strength. The initial effects of chemical etchants on the denture base resin in terms of microstructural changes and flexural strength were also examined. MATERIAL AND METHODS: Forty-two polymethyl methacrylate (PMMA) denture base resin (Meliodent) specimens consisting of 2 plates measuring 30 x 30 x 2 mm were prepared and divided into 7 groups (n = 6). Specimen groups were treated by immersion in acetone for 30 (A30) or 45 (A45) seconds, methyl methacrylate monomer for 180 (M180) seconds, and methylene chloride for 5 (MC5), 15 (MC15) or 30 (MC30) seconds. Group C had no surface treatment and served as the control. Subsequently, an adhesive (Mollosil) and a silicone-based resilient denture liner (Mollosil) were applied to the treated surfaces, and all specimens were immersed in the radiotracer solution (thalium-201 chloride) for 24 hours. Tracer activity (x-ray counts), as a parameter of microleakage, was measured using a gamma camera. For bond-strength measurement, 84 rectangular PMMA specimens (10 x 10 x 40 mm) were surface-smoothed for bonding and treated with the different chemical etchants using the same previously described group configurations. The adhesive and the silicone-based denture liner were applied to the treated surfaces. Tensile bond-strength (MPa) was measured in a universal testing machine. Flexural strength measurement was performed with 49 PMMA specimens (65 x 10 x 3.3 mm according to ISO standard 1567) in 7 groups (n = 7), with 1 flat surface of each treated with 1 of the chemical etchants preceding adhesive application. The flexural strength (MPa) was measured using a 3-point bending test in a universal testing machine. The data were analyzed by 1-way analysis of variance and the Tukey HSD test (alpha = .05). RESULTS: Significant differences were found between the groups in terms of microleakage (P < .0001). The lowest microleakage was observed in group M180 (30,000 x-ray counts) and the highest in the control group (44,000 x-ray counts). The mean bond strength to PMMA resin ranged from 1.44 to 2.22 MPa. All treated specimens showed significantly higher bond strength than controls (P < .01). The flexural strength values all significantly differed (P < .05). All experimental specimens that had chemical surface treatments showed lower flexural strength than controls (P < .05). CONCLUSION: Treating the denture base resin surface with chemical etchants increased the bond strength of silicone-based resilient denture liner to denture base and decreased the microleakage between the 2 materials. Considering the results of both tests together, the use of methyl methacrylate monomer for 180 seconds was found to be the most effective chemical treatment.     

Outcomes of Kidney Transplantations From the Same Deceased Donor to Two Different Recipients: A Single-Center Experience

Background

Kidney transplantation is the best treatment method for end-stage renal disease. Technically, left kidney transplantation is easier than right kidney, and the complication rates in the right are higher than the left kidney. We performed 28 kidney transplantations from 14 deceased donors between November 2010 and May 2016. Our aim was to share our outcomes and experiences about these 28 patients.

Efficacy of 577‐nm Pro‐Yellow laser in port wine stain treatment

A port‐wine stain (PWS) is a congenital capillary malformation that is seen in 0.3–0.5% of newborns. Although many types of lasers have been used to treat PWSs, few studies have investigated the efficacy of 577‐nm Pro‐Yellow lasers. The aim of this study was to establish the efficacy of Pro‐Yellow lasers in PWS treatment. In total, 26 patients, comprising 15 females (57.7%) and 11 males (42.3%) with a mean age of 24.7 ± 11.8 (range 1–50) years were included in the study. All were treated with a 577‐nm Pro‐Yellow laser at 4‐week intervals, 3–10 times. The sessions initially used scan mode and a fluence dose of 24 J/cm² per session, on average. The mean dose was increased by 4 J/cm each session and the maximum dose administered was 44 J/cm². A mean regression of 68.8 ± 13.9% in the size of the lesions over 5.23 ± 2.7 sessions was observed. There was no statistically significant difference between the female and male patients when they were compared in terms of the number of treatment sessions (p = .789) and treatment success (p = .39). These case series demonstrate that the Pro‐Yellow laser is a safe and well‐tolerated treatment for PWSs. However, deep‐seated lesions required more treatment sessions and it was observed that clinically the lesions did not completely disappear.     

Floating-Harbor syndrome: case report

Floating-Harbor syndrome is a rare disorder which is clinically characterized by short stature, retarded speech development, delayed bone ages, triangular face, bulbous nose and thin lips. We described two cases with Floating-Harbor syndrome and briefly reviewed the relevant literature.