Publications (3)2.72 Total impact
Article: Cumulative effect of disinfection procedures on microhardness and tridimensional stability of a poly(methyl methacrylate) denture base resin.[show abstract] [hide abstract]
ABSTRACT: Microwave irradiation has been used for disinfection of dentures instead of chemical solutions; yet, its effect on resin properties after repeated procedures still is unclear. This study evaluated the cumulative effect of two disinfection methods on Knoop microhardness and tridimensional stability of a poly(methyl methacrylate) denture base resin. For the microhardness measurement, 24-resin discs received mechanical polishing and were submitted to the following treatments: (1) control (no disinfection), (2) chemical disinfection (immersion in 100ppm chloride solution for 24h), or (3) microwave disinfection (irradiation at 690 W for 6 min). Disinfection procedures were performed twice (T1, T2) with a 7-day interval. Knoop microhardness was recorded after polishing (T0) and after T1 and T2. For the dimensional stability test (measured by the adaptation of the denture bases), 36-maxillary denture bases were obtained from type III dental stone casts duplicated from a metallic master model and submitted to the disinfection treatment. Adaptation of denture bases was measured at baseline (T0) and after T1 and T2 by weighing a vinyl polysiloxane film reproducing the gap between resin base and master model. Data were analyzed by ANOVA GLM for repeated measures and Bonferroni's test, alpha = 0.05. Knoop microhardness was not modified by any disinfection procedure but decreased over time. Denture resin bases submitted to microwave disinfection had gradual increase of distortion over time, while bases immersed in chloride solution did not differ from the control group and remained dimensionally stable from T1 to T2.Journal of Biomedical Materials Research Part B Applied Biomaterials 09/2008; 86(2):360-4. · 2.15 Impact Factor
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ABSTRACT: This study evaluated the effect of disinfection methods [chemical disinfection (immersion in 100 ppm chloride solution) or microwave disinfection (690 W for 6 min)] on the internal adaptation of denture bases and resin surface roughness. For the adaptation test, 18 maxillary denture bases were obtained from stone casts duplicated from a metallic master model and submitted to the following treatments: 1) control (no disinfection), 2) chemical disinfection or 3) microwave disinfection. Disinfection procedures were performed twice (T1, T2) with a 7-day interval between them. Internal adaptation was measured at baseline (T0) and after T1 and T2 by weighing a vinyl polysiloxane film reproducing the gap between the resin base and the master model. For surface roughness measurement, 60 rectangular (5x10x40 mm) resin specimens were either mechanically or chemically polished and then submitted to the disinfection treatments. Surface roughness (Ra) was recorded after polishing (T0) and after T1 and T2. Data were analyzed by ANOVA GLM for repeated measures and Bonferroni correction at 5% significance level. Bases submitted to microwave disinfection had gradual increase of misfit, while bases immersed in chloride solution did not differ from the control group. Surface roughness increased in the mechanical polishing groups with microwave disinfection and decreased in the chemical polishing groups.Brazilian Dental Journal 02/2006; 17(3):195-200.
Article: Reliability of a digital image method for measuring medial mandibular flexure in dentate subjects.[show abstract] [hide abstract]
ABSTRACT: Medial mandibular flexure (MMF) is the functional approximation of hemi-mandibles in jaw opening and protrusion, which may affect conventional or implant-supported arch prostheses. This study evaluated the intra- and inter-rater reliability of a digital image method for linear measurement of MMF in dentate subjects. Mandibular occlusal impressions in vinyl polysiloxane during rest and maximum opening were obtained from seven adult volunteers. Each impression and the Mitutoyo digital calipers with a 10mm opening were scanned at a 200% magnification. The images were processed using Adobe Photoshop software to get reference points on contralateral first molars. Linear intermolar measurements were taken using the Image Tool software (UTHSCSA), which was calibrated with the standard opening of the digital calipers. Intermolar distance was measured in triplicate for each image by two independent examiners. MMF was calculated by subtracting the intermolar distance in maximum opening (or protrusion) from the distance in rest position. Data were analyzed by intraclass correlation (ICC) tests for estimating intra- and inter-rater reliability. MMF values ranged from -0.21 to 0.44mm. Intra-rater ICCs were 0.982 and 0.993, and inter-rater ICC was 0.696. The present results show excellent intra-rater and good inter-rater reliability of this digital image method for measuring MMF in dentate subjects.Journal of Applied Oral Science 12/2004; 12(4):358-62. · 0.57 Impact Factor