Showing papers by "Allyson Nogueira Moreira published in 2015"
TL;DR: A maximum TP of 25% for QTH and 20% for LED was found, suggesting that ceramic light attenuation could compromise light cured and dual cure resin cements polymerization.
Abstract: The effect of thickness, shade and translucency of CAD/CAM lithium disilicate glass-ceramic on light transmission of light-emitting diode (LED) and quartz-tungsten-halogen units (QTH) were evaluated. Ceramic IPS e.max CAD shades A1, A2, A3, A3.5, high (HT) and low (LT) translucency were cut (1, 2, 3, 4 and 5 mm). Light sources emission spectra were determined. Light intensity incident and transmitted through each ceramic sample was measured to determine light transmission percentage (TP). Statistical analysis used a linear regression model. There was significant interaction between light source and ceramic translucency (p=0.008) and strong negative correlation (R=-0.845, p<0.001) between ceramic thickness and TP. Increasing one unit in thickness led to 3.17 reduction in TP. There was no significant difference in TP (p=0.124) between shades A1 (s1=0) and A2 (s1=-0.45) but significant reduction occurred for A3 (s1=-0.83) and A3.5 (s1=-2.18). The interaction QTH/HT provided higher TP (s1=0) than LED/HT (s1=-2.92), QTH/LT (s1=-3.75) and LED/LT (s1=-5.58). Light transmission was more effective using halogen source and high-translucency ceramics, decreased as the ceramic thickness increased and was higher for the lighter shades, A1 and A2. From the regression model (R2=0.85), an equation was obtained to estimate TP value using each variable s1 found. A maximum TP of 25% for QTH and 20% for LED was found, suggesting that ceramic light attenuation could compromise light cured and dual cure resin cements polymerization.
13 citations
TL;DR: Definition 1 was the most accurate criterion for the definition of mild and moderate periodontitis case to be applied to head and neck cancer individuals before radiotherapy.
Abstract: Purpose Different periodontitis case definitions have been used in clinical research and epidemiology The aim of this study was to determine more accurate criterion for the definition of mild and moderate periodontitis case to be applied to head and neck cancer individuals before radiotherapy Methods The frequency of periodontitis in a sample of 84 individuals was determined according to different diagnostic criteria: (1) Lopez et al (2002);(2) Hujoel et al (2006); (3) Beck et al (1990); (4) Machtei et al (1992); (5) Tonetti and Claffey (2005); (6) and Page and Eke (2007) All diagnosis were based on the clinical parameters obtained by a single calibrated examiner (Kw=071) The individuals were evaluated before radiotherapy They received oral hygiene instructions, and the cases diagnosed with periodontitis (Page and Eke 2007) were treated The gold standard was the definition 6, and the others were compared by means of agreement, sensitivity (SS), specificity (SP), and the area under ROC curve The kappa test evaluated the agreement between definitions Results The frequency of periodontitis at baseline was 536 % (definition 1), 810 % (definition 2), 405 % (definition 3), 262 % (definition 4), 131 % (definition 5), and 702 % (definition 6) The kappa test showed a moderate agreement between definitions 6 and 2 (590 %) and definitions 6 and 1 (560 %) The criterion with higher SS (092) and SP (073) was definition 1 Conclusion Definition 1 was the most accurate criterion to case periodontitis definition to be applied to head and neck cancer individuals
13 citations
TL;DR: Although stress concentration analyses of the isotropic 3D models produced similar stress distribution results when compared to the anisotropic models, tensile stress values shown by anisotrop models were smaller than the isotopic models.
Abstract: The aim of this study was to compare the areas of stress concentration in a three-dimensional (3D) premolar tooth model with anisotropic or isotropic enamel using the finite element method. A computed tomography was imported to an image processing program to create the tooth model which was exported to a 3D modeling program. The mechanical properties and loading conditions were prescribed in Abaqus. In order to evaluate stresses, axial and oblique loads were applied simulating realistic conditions. Compression stress was observed on the side of load application, and tensile stress was observed on the opposite side. Tensile stress was concentrated mainly in the cervical region and in the alveolar insertion bone. Although stress concentration analyses of the isotropic 3D models produced similar stress distribution results when compared to the anisotropic models, tensile stress values shown by anisotropic models were smaller than the isotropic models. Oblique loads resulted in higher values of tensile stresses, which concentrate mainly in the cervical area of the tooth and in the alveolar bone insertion. Anisotropic properties must be utilized in enamel stress evaluation in non-carious cervical lesions.
12 citations
TL;DR: The use of 40% CHX varnish decreases the gingival overgrowth in patients undergoing orthodontic treatment and further studies are necessary to set the action time and frequency of application.
Abstract: Introduction: Fixed orthodontic appliances patients suffer limitations on the effective control of biofilm by mechanical methods, bringing the need of a coadjutant in the control of inflammation and oral health improvement.Objective: The aim of this prospective split-mouth blind study was to analyze the effect of a 40% chlorhexidine (CHX) varnish on gingival growth of patients with orthodontic fixed appliances. Methods: Healthy teenage patients with fixed orthodontic appliances and increased gingival volume were recruited (n = 30). Each individual was his own control, having in the maxilla one control side and one treatment side. An application of varnishes occurred on the vestibular area of the upper premolars and first molar crowns, on the control side (placebo varnish) and on the experimental side (EC40(r) Biodentic CHX varnish). The varnishes and sides were randomly chosen and its identification and group was kept by a third party observer and it was not revealed to the researchers and participants until the end of study. In order to establish a baseline registration, digital photographs were taken by a trained photographer before varnish application at baseline (T0), as well as 14 days (T14) and 56 days (T56) after the application. The gingival volume was calculated indirectly using the vestibular areas (mm2) of the upper second premolars' clinical crowns by RapidSketch(r) software, at all study times. The data were analyzed using ANOVA and the Turkey-Krammer test.Results:It was observed, in the final sample of 30 individuals, that at T0, the control and treatment groups were similar. At T14 and T56, a progressive reduction of the clinical crown area was seen in the control group, and an increase in the average area was detected in the experimental group (p < 0,05).Conclusions: The use of 40% CHX varnish decreases the gingival overgrowth in patients undergoing orthodontic treatment. Further studies are necessary to set the action time and frequency of application.
8 citations
TL;DR: Clinical protocols can use ICDAS for the severity diagnosis of occlusal caries, but the LAA performance was poor.
Abstract: Clinical Relevance The ICDAS proved to be a reproducible method with good performance in detecting carious lesions in the dentin threshold. The ICDAS-LAA criteria were reproducible to assess caries activity, but with a low degree of accuracy.
7 citations
TL;DR: The digital workflow presented herein shows high accuracy for a virtually planned implant with flapless guided placement, allowing the successful delivery of a definitive presurgical zirconium single crown in an esthetic area in a single visit.
Abstract: This paper describes the digital workflow from cone beam computer tomography (CBCT) to the installation of a definitive presurgical zirconium individual crown in a 19-year-old woman requiring implant replacement of a maxillary right lateral incisor. The patient had agenesis of this tooth and had completed the orthodontic treatment. CBCT was conducted and diagnostic casts were digitized. Virtual planning was completed by defining a prosthetically driven implant and a stereolithographic surgical template was produced. Good adaptation of a stereolithographic surgical template was verified in the working cast. Implant and abutment were installed in this cast using a stereolithographic surgical template, and a CAD/CAM definitive zirconium crown was produced. Flapless computer-guided implant surgery was performed. The abutment was connected, and a definitive zirconium crown was cemented using resin cement. The digital workflow presented herein shows high accuracy for a virtually planned implant with flapless guided placement, allowing the successful delivery of a definitive presurgical zirconium single crown in an esthetic area in a single visit. The patient was revaluated after 1 year of function with an excellent outcome of the treatment.
4 citations
TL;DR: The differences in marginal bone level reported between SFP and CFP in some clinical studies may not be related to a mechanical factor, and the stresses and displacements on perimplant bone generated by screw- and cement-retained prostheses were compared using the finite element method.
Abstract: Purpose: To compare the stresses and displacements on perimplant bone generated by screw- and cement-retained prostheses using the finite element method. Materials and Methods: Two models were constructed: partial fixed implant-supported prostheses with three elements retained by screws (SFP) or cement (CFP). Vertical and oblique loads of 100 N were applied on the models. Bone was analyzed by the principal stresses σ1 and σ3. The displacement between the implant and the bone was identified by the penetration and gap. Results: Results showed a similar pattern in the distribution of the principal stresses between both prostheses. Under the σ1 stresses, the SFP showed similar values in the bone compared with the CFP. The analysis of the σ3 showed stress peaks 28% higher in the SFP, considering vertical and oblique loads. Displacement analysis showed a similar pattern and similar values between the prostheses for penetration and gap under both loads. Conclusions: There were no important differences in the σ1 analysis and the displacement between the SFP and CFP. The differences in marginal bone level reported between SFP and CFP in some clinical studies may not be related to a mechanical factor.
2 citations