Publications by authors named "Marina Amaral"

59 Publications

Tooth Discoloration Using Calcium Silicate-Based Cements For Simulated Revascularization in Vitro.

Braz Dent J 2021 Jan-Feb;32(1):53-58

Postgraduate Program in Dentistry, School of Dentistry, University of Taubaté, Taubaté, Brazil.

The endodontic revascularization may be an alternative treatment for necrotic immature teeth, however, several treatment steps may cause tooth discoloration. This study evaluated the use of three calcium silicate-based cements with different radiopacifying agents on the color alteration (∆E) of extracted premolars after simulation of revascularization. Forty single rooted extracted premolars were shaped with #1-6 gates Glidden drills, rinsed with sodium hypochlorite, and filled with fresh human blood. Three calcium silicate-based cements with different radiopacifying agents (bismuth oxide - CSBi, calcium tungstate - CSW, and zirconium oxide - CSZr) were applied over the blood clot (n=10). The control group received the application of a temporary zinc oxide-based cement (TFZn) (n=10). ∆E was measured with a spectrophotometer, using the L*a*b* color system of the International Commission on Illumination (CIELab), in different times: prior to the preparation of the access cavity (t0); right after treatment (t1); and after one (t2), two (t3), three (t4) and four (t5) months. The tooth site for color evaluation was standardized by silicon matrix, the color reading was performed 3 times per tooth, and the teeth were stored in 37º water between evaluations. ∆E, whiteness (WID index) and yellowness (b*) were evaluated. Data were subjected to one-way ANOVA and repeated measures ANOVA, followed by Tukey's post hoc test (α=0.05). All groups were similar in ∆E1 (t0-t1). The ∆E was the lowest and constant in the control group. In all evaluation times, CSBi presented the highest ∆E (p<0.01). CSW and CSZr were similar in all evaluated times and presented intermediate ∆E values. WID index from CSBi and CSW presented more distancing from 'white' reference. CSBi presented the greatest decrease in yellowness (b* value). The cement containing bismuth oxide presented the highest color alteration values. All tested calcium silicate-based cements presented clinically perceptible discoloration. Calcium tungstate and zirconium oxide may be used as alternative radiopacifiers to decrease tooth discoloration after endodontic tooth revascularization.
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http://dx.doi.org/10.1590/0103-6440202103700DOI Listing
May 2021

Failure load and shear bond strength of indirect materials bonded to enamel after aging.

Gen Dent 2021 May-Jun;69(3):24-29

This study evaluated the failure load and the shear bond strength of 4 block materials indicated for computer-aided design/computer-aided manufacturing (CAD/CAM) of dental veneers: lithium disilicate, feldspathic ceramic, polymer-infiltrated ceramic, and nanohybrid composite. The tested hypothesis was that the material that combined an elastic modulus similar to that of enamel with the highest bond strength values would present the highest failure load. From prefabricated CAD/CAM blocks, disc-shaped specimens (6.0 × 0.7 mm; n = 10) and cylinders (2.4 × 2.5 mm; n = 10) were fabricated for load-to-failure and shear bond strength tests, respectively. Materials were adhesively bonded to flattened bovine enamel surfaces, stored in distilled water at 37°C for 90 days, and subjected to thermocycling (2000 cycles of 5°C to 55°C). Discs of restorative material were bonded to enamel and subjected to an increasing load that was applied perpendicular to the bonding interface until catastrophic failure occurred. A chisel was used to apply an increasing load parallel to the adhesive interface between the enamel and a cylinder of restorative material to measure shear bond strength. Data were subjected to a Weibull analysis and 1-way analysis of variance followed by a Tukey post hoc test (α = 0.05). The type of restorative material significantly affected the (mean [SD]) failure load when bonded to enamel (P = 0.006): polymer-infiltrated ceramic (1167.9 [310.2] N) = feldspathic ceramic (1115.0 [382.0] N) = nanohybrid composite (1067.3 [251.0] N) > lithium disilicate (786.2 [304.5] N). The type of restorative material also significantly affected the (mean [SD]) bond strength to enamel (P < 0.001): lithium disilicate (32.81 [11.19] MPa) = polymer-infiltrated ceramic (27.04 [7.65] MPa) > feldspathic ceramic (21.11 [9.16] MPa) > nanohybrid composite (9.08 [3.66] MPa). The polymer-infiltrated ceramic presented the best performance when bonded to enamel.
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April 2021

Lithium Disilicate Ceramic Endocrown Biomechanical Response According to Different Pulp Chamber Extension Angles and Filling Materials.

Materials (Basel) 2021 Mar 9;14(5). Epub 2021 Mar 9.

Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98123 Messina, Italy.

The purpose of this study is to evaluate the effect of pulp chamber extension angles and filling material mechanical properties on the biomechanical response of a ceramic endocrown. A 3D model of maxillary molar that underwent endodontically treatment was exported to computer aided design software to conduct finite element analysis (FEA). The endocrown model was modified considering different pulp chamber extension angles (right angle; 6°, 12° and 18° of axial divergence). The solids were imported into the computer aided engineering software in Standard for the Exchange of Product Data (STEP) format. Nine different filling materials were simulated to seal the orifice of the root canal system under each endocrown restoration (resin composite, bulk-fill resin composite, alkasite, flowable resin composite, glass ionomer cement, autocured resin-reinforced glass ionomer cement, resin cement, bulk-fill flowable resin composite, zinc oxide cement), totaling 36 models. An axial load (300 N) was applied at the occlusal surface. Results were determined by colorimetric graphs of von-Misses stress (VMS) and Maximum Principal Stress (MPS) on tooth, cement layer, and endocrown restorations. VMS distribution showed a similar pattern between the models, with more stress at the load region for the right-angled endocrowns. The MPS showed that the endocrown intaglio surface and cement layer showed different mechanical responses with different filing materials and pulp chamber angles. The stress peaks plotted in the dispersion plot showed that the filling material stiffness is proportional to the stress magnitude in the endocrown, cement layer and tooth adhesive surface. In addition, the higher the pulp chamber preparation angle, the higher the stress peak in the restoration and tooth, and the lower the stress in the cement layer. Therefore, 6° and 12° pulp chamber angles showed more promising balance between the stresses of the adhesive interface structures. Under the conditions of this study, rigid filling materials were avoided to seal the orifice of root canal system when an endocrown restoration was planned as rehabilitation. In addition, the pulp chamber axial walls were prepared between 6° and 12° of divergence to balance the stress magnitude in the adhesive interface for this treatment modality.
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http://dx.doi.org/10.3390/ma14051307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7963147PMC
March 2021

Improving the bonding stability between resin cements and zirconia-based ceramic using different surface treatments.

Int J Prosthodont 2021 Feb 26. Epub 2021 Feb 26.

Purpose: To evaluate the effects of airborne-particle abrasion with alumina particles or silicamodified alumina particles on the bond strength between zirconia and conventional MDP-based (Ph; Panavia F 2.0, Kuraray) or self-adhesive (SA; RelyX U200, 3M ESPE) resin cements.

Materials And Methods: Five surface treatments were evaluated: C = no surface treatment; AB = airborne-particle abrasion with alumina particles (BIO-ART Dental Supplies and Equipment); ABP = AB combined with MDP-based primer (Alloy Primer, Kuraray); SS = airborne-particle abrasion with silica-modified alumina particles (CoJet, 3M ESPE) combined with silane (RelyX Ceramic Primer, 3M ESPE); and SSP = SS combined with MDP-based primer. The surface roughness (Ra) of the airborne particle-abraded samples (n = 5) was measured by a contact profilometer (Mitutoyo Surftest SJ-401, Mitutoyo). Cylinders of the resin cements tested were bonded to the surface-treated zirconia. The microshear test was performed by the application of a load with a wire loop parallel to the adhesive interface until debonding of the resin cement cylinders. The microshear bond strength (μSBS) of the samples was measured before and after being subjected to thermocycling (TC; 5°C to 55°C, 60 seconds dwell time for 3,000 cycles; MSCT, Marcelo Nucci). One-way (Ra) and two-way (μSBS) analysis of variance followed by Tukey post hoc test (α = .05) were used.

Results: The SS (Ph: 12.6 MPa; Ph-TC: 6.37 MPa; SA: 11.8 MPa; SA-TC: 9.37) and SSP (Ph: 10.4 MPa; Ph-TC: 5.82 MPa; SA: 10.4 MPa; SA-TC: 10.0) surface treatments produced the highest surface roughness values (P < .001). The SS samples achieved the highest immediate bond strength for both resin cements. However, after TC, SA resin cement associated with any surface treatment produced the highest bond strength values.

Conclusion: The self-adhesive resin cement promoted higher and more stable bond strength values when associated with a surface roughening method.
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http://dx.doi.org/10.11607/ijp.6797DOI Listing
February 2021

Educational Impact of Notebook Covers on the Knowledge of Sixth-Grade Primary Pupils About Tooth Avulsion and Replantation: A Randomized Trial.

Health Educ Behav 2021 Feb 25:1090198121991468. Epub 2021 Feb 25.

Universidade Estadual Paulista, Araçatuba, Araçatuba, São Paulo, Brazil.

Background: Tooth avulsion is a common cause of tooth loss. However, there is a significant lack of knowledge about dental trauma and the appropriate emergency procedures to handle these cases.

Aim: The aim of this study was to evaluate the educational effect of notebook covers illustrated with figures and informative texts about tooth avulsion and replantation in sixth-grade primary school pupils.

Material And Methods: Sixth-grade pupils of two public school participated in this study. An experimental group consisting of 134 pupils received notebook covers illustrated with figures and informative texts about tooth avulsion and replantation, while a control group of 108 pupils received notebooks with neutral covers. An assessment of the educational effects on pupils was performed after 9 months, with a standardized questionnaire normally used to evaluate dental trauma. Statistical analysis was conducted with SPSS 21.0 (α = .05) for group description and comparison using chi-square and Student tests.

Results: Compared with the control group, the experimental group showed statistically significant improvements in correct meaning of dental trauma (38% vs. 58.2%); procedures to follow in the case of dental avulsion (2.8% vs. 70.9%); storing the avulsed tooth in milk (18.5% vs. 76.9%); general knowledge about dental anatomy (61.1% vs. 95.5%); and the ideal time for the tooth to remain outside the mouth prior to replantation (20.4% vs. 59.7%).

Conclusion: The use of notebook covers illustrated with figures and informative texts about dental trauma led to a significant increase in the knowledge of schoolchildren about tooth avulsion, first aid, and replantation.
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http://dx.doi.org/10.1177/1090198121991468DOI Listing
February 2021

The effect of repeated surface treatment of zirconia on its bond strength to resin cement.

J Adv Prosthodont 2020 Oct 26;12(5):291-298. Epub 2020 Oct 26.

Department of Dental Prosthesis, School of Dentistry, University of Taubaté, Taubaté, Brazil.

Purpose: The aim of this study is to evaluate the influence of repeated surface treatments on wettability and surface roughness for zirconia surface and bond strength of zirconia-based ceramics to resin cement.

Materials And Methods: Seventy blocks (10 × 10 × 3 mm) of zirconia-based ceramics were fabricated and divided into two groups according to the surface treatments: (A) 110 µm AlO airborne-particle abrasion and (R) 110 µm silica modified AlO airborne-particle abrasion. At stage 2, each group was subdivided into 5 groups according to the surface retreatments: (a) 110 µm AlO airborne-particle abrasion, (r) 110 µm silica modified AlO airborne-particle abrasion, (D) diamond bur, (Da) diamond bur + 110 µm AlO airborne-particle abrasion, and (Dr) diamond bur + 110 µm silica modified AlO airborne-particle abrasion. Cylinders of self-adhesive resin cement were cemented onto each treated ceramic surface and subjected to micro-shear bond strength test. Additional specimens were prepared for roughness and wettability analyses. The data were subjected to t-test and One-way ANOVA followed by Tukey's post hoc test (α=.05).

Results: At stage 1, group R presented higher bond strength values than group A (=.000). There was a statistically significant increase of bond strength at stage 2 for group A (=.003). The diamond bur influenced the surface roughness, increasing the values (=.023). Group R provided better wettability. Regardless of the applied surface treatment, most of failures were adhesive.

Conclusion: The combination of application and reapplication of Rocatec Plus showed the best results of bond strength. Surface retreatment and recementation might be an indicated clinical strategy.
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http://dx.doi.org/10.4047/jap.2020.12.5.291DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7604241PMC
October 2020

Biomechanical evaluation of anterior implants associated with titanium and zirconia abutments and monotype zirconia implants.

J Prosthodont Res 2021 Feb 9;65(1):73-77. Epub 2020 Sep 9.

Department of Prosthodontics, Dental School, University of Taubaté, Rua dos Operários 09, 12020-270, Taubaté, SP.

Purpose: The present in silico study evaluated the behavior of titanium dental implants associated with abutments in zirconia and monotype zirconia implant using finite element analysis (FEA).

Methods: A partial image of the anterior region of the maxilla was obtained by computed tomography. Three models of finite element were made using 3D modeling software (SolidWorks): Ti-Ti (control): implant morse cone (3.75 x 11mm; NobelActive) and titanium abutment (Esthetic Abutment); Ti-Zr: cone morse implant in titanium (3.75 x 11mm; NobelActive) and zirconia abutment (Procera Esthetic Abutment #9); Zr: monotype zirconia implant (4.1 x 12mm; Straumann Pure Ceramic). Computerized crowns of element 11 in lithium disilicate (IPS e.max Press, Ivoclar Vivadent) cemented in all groups were created. A load of 100N (45º) was applied simulating the excursion movement of the incisal guide. The von Mises, modified von Mises, maximum (tensile) and minimum (compression) principal stresses were obtained, compared and used for the quantitative and qualitative evaluation of the groups.

Results: The Zr presented the lowest values of maximum, minimum, and von Mises tensions than the two pieces systems (Ti-Ti and Ti-Zr). Ti-Zr group had the highest values of tensions evaluated in this study.

Conclusions: The type of material as well as the geometry of implant influenc ed the tension values evaluated.
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http://dx.doi.org/10.2186/jpr.JPOR_2019_527DOI Listing
February 2021

FoxP3+ regulatory T cells in oral tongue squamous cell carcinoma in young and older patients.

Braz Oral Res 2020 17;34:e096. Epub 2020 Aug 17.

Department of Dentistry, Universidade Estadual da Paraíba, Campina Grande, PB, Brazil.

Regulatory T (Treg) cells can suppress antitumor immune response, but little is known about possible age-related differences in the number of these cells in the microenvironment of oral tongue squamous cell carcinoma (OTSCC). The aim of this study was to determine the number of FoxP3+ Treg cells in the microenvironment of OTSCC in young (≤ 45 years) and older (≥ 60 years) patients, and to correlate the findings with clinicopathological parameters (sex, tumor size/extent, regional lymph node metastasis, clinical staging, and histopathological grade of malignancy). Forty-eight OTSCCs (24 diagnosed in young patients and 24 diagnosed in older patients) were selected. Lymphocytes exhibiting nuclear immunopositivity for FoxP3 were quantified at the tumor invasive front and the results were analyzed statistically using the non-parametric Mann-Whitney test. FoxP3+ lymphocytes were observed in all cases assessed. The number of FoxP3+ lymphocytes in OTSCC tended to be higher in older patients (p = 0.055). Analysis of OTSCC in males and in early clinical stages revealed a higher number of Treg cells in older patients than in young ones (p < 0.05). In older patients, the number of Treg cells tended to be higher in smaller tumors (p = 0.079). Tumors with intense inflammatory infiltrate exhibited a larger number of Treg cells, both in young (p = 0.099) and older patients (p = 0.005). The results suggest a greater participation of Treg cells in immunoinflammatory responses in the microenvironment of OTSCC in older patients, particularly in males and in early stages.
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http://dx.doi.org/10.1590/1807-3107bor-2020.vol34.0096DOI Listing
October 2020

Mechanical performance of monolithic materials cemented to a dentin-like substrate.

J Prosthet Dent 2020 May 20;123(5):753.e1-753.e7. Epub 2020 Feb 20.

Professor, Dental Prosthesis, Department of Dentistry, University of Taubate (UNITAU), Taubate, Brazil. Electronic address:

Statement Of Problem: Studies on the mechanical behavior of restorative materials bonded to tooth structure and considering the properties of the material and the bonding between both substrates are lacking.

Purpose: The purpose of this in vitro study was to evaluate the hardness, fracture toughness, load-to-failure, cyclic fatigue, and stress distribution of 4 computer-aided design and computer-aided manufacturing (CAD-CAM) materials when bonded to a substrate similar to dentin (G10).

Material And Methods: Disks (11×1.2 mm) of lithium disilicate (LD), feldspathic ceramic (FC), polymer-infiltrated ceramic (PC), and a nanohybrid composite resin (NC) were fabricated (n=45) and had their surfaces polished. Microhardness was measured by the Knoop indentation (19.61 N, 12 seconds, n=5). Indented specimens were subjected to biaxial flexural strength testing, and the fracture origin defect was measured to calculate fracture toughness (n=5). Forty disks from each material were adhesively bonded to G10. Half of the specimens were subjected to load-to-failure testing, and remaining specimens (n=20) were subjected to cyclic fatigue (400 N, 10 cycles). The test was suspended every 200 000 cycles, and specimens were examined for cracks, debonding, or catastrophic failure. Obtained data were evaluated by analysis of variance and the Tukey post hoc test (α=.05). Weibull analysis was also performed. A 3D model of the tested specimens was constructed in a design software program, and the stress distribution was evaluated by finite element analysis, with the application of a 100-N load normal to the restoration surface.

Results: Hardness values with statistically significant differences were LD (540.4)>FC (474.6)>PC (176.6)>NC (58.26). Fracture toughness vales (MPa.m) and statistical significance were as follows: LD (2.25)=NC (2.46)>FC (1.14)=PC (1.18). Load-to-failure values (N) were LD (2881.6)=FC (2881.6)=PC (3200.6)>NC (2367.5). A specimen each of LD and NC fractured during the fatigue test, and LD and PC had a high percentage of subsurface cracks (55% and 75%, respectively). The FC had the lowest debonding rate after load-to-failure testing and no catastrophic fractures or cracks during fatigue.

Conclusions: The materials tested had different mechanical behaviors depending on the tests performed. Feldspathic ceramic had the best fatigue behavior when cemented to a dentin-like substrate.
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http://dx.doi.org/10.1016/j.prosdent.2019.12.021DOI Listing
May 2020

Can skinfold thickness equations be substituted for bioimpedance analysis in children?

J Pediatr (Rio J) 2021 Jan-Feb;97(1):75-79. Epub 2020 Feb 19.

Pontifícia Universidade Católica do Rio Grande do Sul (PUC-RS), Departamento de Pediatria e Saúde Infantil, Porto Alegre, RS, Brazil. Electronic address:

Objective: The aim of the present study was to evaluate the agreement between the most used skinfold thickness equations with multi-frequency bioimpedance analysis in the prediction of body fat levels in children.

Method: A cross-sectional study of healthy Brazilian community-dwelling individuals. The anthropometric assessment included height, body mass, arm circumference, and waist circumference. The percentage of body fat was obtained by measuring skinfold thickness equations and using bioimpedance analysis, and skinfold thickness was measured using a scientific skinfold caliper. Bland-Altman plot analysis was used to verify the agreement between the methods.

Results: There were 439 children and adolescents evaluated, with a mean age of 11.6±3.7 years. The mean body fat by bioimpedance analysis was 22.8%±10.4%, compared to 22.4%±8.8% by Slaughter (1), 20.4%±9.2% by Slaughter (2), 19.6%±4.4% by Goran, and 24.7%±10.0% by Huang equations. Bland-Altman plot analysis revealed limits of agreement greater than 8% between the bioimpedance analysis approach and equations, exceeding the clinically acceptable limit predefined a priori. None of the equations had good agreement with bioimpedance analysis.

Conclusion: It was concluded that skinfold thickness and bioimpedance analysis should not be used interchangeably in children and adolescents.
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http://dx.doi.org/10.1016/j.jped.2019.12.006DOI Listing
February 2021

Effect of repeated firings and staining on the mechanical behavior and composition of lithium disilicate.

Dent Mater 2020 05 13;36(5):e149-e157. Epub 2020 Feb 13.

Institute of Science and Technology, UNESP - Paulista State University, São José dos Campos, São Paulo, Brazil. Electronic address:

Objective: To evaluate the composition, flexural strength and fatigue behaviour of lithium disilicate ceramic (LD) after repeated firings and different staining techniques.

Methods: LD discs were fabricated and divided according to number of firing cycles and staining technique: CO - control, discs were crystallized (850°C/10min); SC - single-step characterization - crystallization and staining (applied with a thin brush) were performed in a single step with one firing cycle (850°C/10min); and DC - double-step characterization - crystallization firing cycle was performed first (850°C/10min), followed by staining firing cycle (770°C/90s). Specimens were fired two, four or six times (one crystallization firing cycle and one, three or five staining firing cycles), resulting into 9 groups (n=30): COII, COIV, COVI, SCII, SCIV, SCVI, DCII, DCIV and DCVI. The composition of the specimens was investigated (EDS, XRD, Raman spectroscopy), and the biaxial flexural strength (n=10) and staircase tests (n=20, 5×10 cycles, 5Hz) were performed. Data were subjected to one-way ANOVA and Tukey's test (α=0.05).

Results: EDS and XRD revealed amorphous content for stained groups. Biaxial flexural strength was not affected by repeated firings in any group, but stained groups presented lower flexural strength than control groups (p=0.001). The fatigue limit results decreased in all groups compared to flexural strength. SC groups showed similar (SCII and SCIV) or even higher fatigue limits (SCVI) than the control groups, and DC showed the lowest fatigue limit values. SEM and Raman suggested that the interfaces between staining and the LD showed only an overlap for the DC groups, whereas for the SC it was suggested an interaction between the stain and the LD.

Significance: Repeated firings did not result in decreased lithium disilicate flexural strength.Staining affected flexural strength and also resulted in increased amorphous content in the characterized specimens. Single-step staining resulted in the highest fatigue limit.
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http://dx.doi.org/10.1016/j.dental.2020.02.003DOI Listing
May 2020

Effect of staining and repeated firing on the surface and optical properties of lithium disilicate.

J Esthet Restor Dent 2020 Jan 19;32(1):113-118. Epub 2019 Dec 19.

Department of Dental Materials and Prosthodontics, São José dos Campos Dental School, Institute of Science and Technology, UNESP-Paulista State University, São José dos Campos, Brazil.

Objective: Evaluate the effect of staining and repeated firings on color, translucency and surface proprieties of CAD/CAM lithium disilicate (LD).

Material And Methods: One hundred eighty LD discs were made (ISO 6872) and distributed in different groups (n = 20): control (CO)-no treatment; single-step characterization (SC)-crystallization and staining fired together; and double step characterization (DC)-crystallization and then staining. The samples were submitted to two, four, or six firings, resulting in nine groups: COII, COIV, COVI, SCII, SCIV, SCVI, DCII, DCIV, and DCVI. The color and translucency were measured by a reflectance spectrophotometer. Surface roughness (Ra) and Vickers nano-hardness were also measured. ANOVA and Tukey statistical tests were used (α = .05).

Results: Only CO and DC demonstrated significant color alterations (ΔE > 1.8). SC and DC did not show changes in translucency by the number of firings (P > .05); however, for CO (P = .02) these values increased. Nano-hardness was similar in all groups (P > .05). Ra values indicated differences due to the type of characterization (SC presented the highest values) and number of firings (CO and DC groups) (P < .01).

Conclusion: SC promoted color, translucency, and roughness stability after repeated firings.

Clinical Significance: The single characterization technic in CAD/CAM lithium disilicate presents good color, translucency, and hardness stability, which promote predictable results to monolithic restoration.
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http://dx.doi.org/10.1111/jerd.12558DOI Listing
January 2020

Stress distribution of complete-arch implant-supported prostheses reinforced with silica-nylon mesh.

J Clin Exp Dent 2019 Dec 1;11(12):e1163-e1169. Epub 2019 Dec 1.

DDs, MSc, PhD, Professor, Department of Prosthodontics, Brazcubas Education, Mogi das Cruzes, Brazil.

Background: This study evaluated the presence of a silica-nylon mesh and two cantilever lengths on the biomechanical behavior of complete-arch implant-supported prostheses.

Material And Methods: Twenty-four (24) complete mandibular arch implant-supported prostheses were divided into 4 groups according to the presence of reinforcing mesh (with or without) and the cantilever length (molar - 15 mm or premolar - 5 mm). The specimens were submitted to strain gauge analysis (30-kgf, 10 s) at different points (molar and premolar). Three-dimensional models were created based on the in vitro specimens, and the results in the bone (microstrain), prostheses (tensile stress), implants and prosthetic screws (von-Mises stress) were evaluated using the finite element method (FEM). All materials were considered homogeneous, isotropic and linear. Strain gauge data were submitted to 3-way analysis of variance and the Tukey test (α=.05). FEM results were qualitatively analyzed using colorimetric graphs.

Results: The microstrain magnitude for the prostheses with reinforcement was 519.91±359 and 583.33±661 without reinforcement (=.001). The microstrain values for loading on the molar was 867.49±784 and on the premolar was 235.75±145. FEM corroborated with the in vitro findings for the bone behavior. The load application in the premolar showed reduced stress concentration, and a significant difference was observed between the presence or absence of the reinforcement for the prostheses.

Conclusions: Silica-nylon mesh reduced the peri-implant microstrain and the prosthesis stress regardless of the cantilever extension. For temporary complete-arch implant-supported prostheses, the limitation of the cantilever to the premolar region improves the biomechanical response during load application. Finite element analysis, biomechanical response, dental implants, prosthetic dentistry.
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http://dx.doi.org/10.4317/jced.56470DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894919PMC
December 2019

Effect of Implant Platform Connection and Abutment Material on Removal Torque and Implant Hexagon Plastic Deformation.

Eur J Dent 2019 Jul 3;13(3):349-353. Epub 2019 Dec 3.

Department of Dentistry, University of Taubaté, Taubaté, Brazil.

Objectives:  The aim of this study was to evaluate the plastic deformation of the hexagonal connection, and the removal torque of the implant-abutment joint of two dental implants combined with internal or external hexagonal connection implants after mechanical cycling.

Materials And Methods:  Twenty-four dental implants were used in the study. Half of the implants had internal hexagonal connections (IH; Titamax II Plus) and the other half had external hexagonal connections (EH; Titamax Ti Ex). Four groups of two types of dental implant abutments (titanium: Ti, UCLA II Plus and zirconia: Zr, fabricated by CAD/CAM; = 6) were investigated. The abutments received a metallic crown and the settings were submitted to mechanical cycling (MC; 10 cycles, axial load, 120N). The connection surface area was measured by scanning electron microscope (SEM) images. The removal torque was evaluated and the plastic deformation of the hexagonal surface of the implant was measured by comparing the images before and after MC.

Statistical Analysis:  Paired- test was used to analyze the data statistically at a significance level of α = 0.05.

Results:  The torque values decreased for all groups after MC, and the hexagonal surface area decreased due to plastic deformation for IH and EH associated with Zr abutments.

Conclusions:  Zirconia abutments showed the worst plastic deformation of the implant connection surface and torque loosening when associated with IH implant.
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http://dx.doi.org/10.1055/s-0039-1700662DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6890484PMC
July 2019

Immunoexpression of human leukocyte antigen-DR in actinic cheilitis and lower lip squamous cell carcinoma.

Braz Oral Res 2019 Aug 29;33:e085. Epub 2019 Aug 29.

Universidade Estadual da Paraíba - UEPB, Department of Dentistry, Campina Grande, PB, Brazil.

The aim of this study was to evaluate the immunoexpression of human leukocyte antigen-DR (HLA-DR) in actinic cheilitis (AC) and lower lip squamous cell carcinoma (LLSCC), and to correlate the findings with clinical (tumor size/extent, regional lymph node metastasis, and clinical stage) and histopathological (grade of epithelial dysplasia and inflammatory infiltrate for AC and histopathological grade of malignancy for LLSCC) parameters. Twenty-four AC and 48 LLSCC cases (24 with regional nodal metastasis and 24 without regional nodal metastasis) were selected. The scores of immunopositive cells for HLA-DR in the epithelial component of the lesions were assessed and the results were analyzed statistically using the nonparametric Mann-Whitney test. Epithelial expression of HLA-DR was observed in only five (20.8%) cases of AC (two low-grade and three high-grade lesions), with a very low median score of immunopositivity. By contrast, expression of HLA-DR was found in most LLSCC (97.9%), with a relatively high median score of positive cells. The score of HLA-DR-positive cells tended to be higher in tumors with regional lymph node metastasis, tumors in advanced clinical stages, and low-grade tumors, but the difference was not statistically significant (p > 0.05). In addition, there was a tendency towards higher expression of HLA-DR in highly/moderately keratinized tumors, and tumors with little/moderate nuclear pleomorphism (p > 0.05). The results suggest a potential role of HLA-DR in lip carcinogenesis, particularly in the development and progression of LLSCC. The expression of this protein can be related to the degree of cell differentiation in these tumors.
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http://dx.doi.org/10.1590/1807-3107bor-2019.vol33.0085DOI Listing
August 2019

Body composition parameters can better predict body size dissatisfaction than body mass index in children and adolescents.

Eat Weight Disord 2020 Oct 23;25(5):1197-1203. Epub 2019 Jul 23.

Programa de Pós-graduação em Pediatria e Saúde da Criança, Pontifícia Universidade Católica do Rio Grande do Sul e Programa de Pós-graduação em Medicina e Ciências da Saúde, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga 6690, second floor, Porto Alegre, RS, 90610-000, Brazil.

Purpose: Recent studies suggest that body mass index is not a reliable enough measurement for body composition in individuals, particularly in older and younger people. However, most research on body image has used the body mass index (BMI) as a physiological predictor of body satisfaction, particularly in children. The aim of this study was to investigate whether body composition is a better predictor of body size dissatisfaction in children than BMI.

Methods: This is a cross-sectional study. Healthy children and adolescents aged 5-19 years, sex male and female, were recruited using a convenience sample in Brazil. BMI was measured according to the international standardization method and body composition was measured by bioelectrical impedance analysis (BIA) with a portable device model (BIA InBodyS10 multi-frequency, USA). Body size dissatisfaction was assessed using the Kakeshita's Figure Rating Scale for Brazilian Children. Data were analyzed with logistic regression analysis.

Results: A total of 547 participants were evaluated, including 54% females and 67% Caucasian, with a mean age of 11.4 ± 3.8 years. The mean BMI was 20.5 ± 4.6 kg/m, and the mean percentages of fat and lean mass were 23.01 ± 10.59% and 72.84 ± 10.03%, respectively. In the multivariable model, only body composition was significantly associated with body size dissatisfaction (odds ratio: 1.849 (1.085-3.149, p = 0.024) and 1.828 (1.043-3.202, p = 0.035), respectively).

Conclusions: Body composition measures can better predict body size dissatisfaction in children and adolescents than BMI. This result may be relevant for the design of future studies on physiological indicators and body satisfaction.

Level Of Evidence: Level V, cross-sectional study.
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http://dx.doi.org/10.1007/s40519-019-00750-4DOI Listing
October 2020

Newer vs. older CAD/CAM burs: Influence of bur experience on the fatigue behavior of adhesively cemented simplified lithium-disilicate glass-ceramic restorations.

J Mech Behav Biomed Mater 2019 07 9;95:172-179. Epub 2019 Apr 9.

Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp) - Institute of Science and Technology, São José dos Campos, Brazil. Electronic address:

This study evaluated the effect of the CAD/CAM burs experience (newer vs older as consequence of the milling sequence) on fatigue failure load (FFL), number of cycles for failure (CFF), and survival rates of lithium disilicate glass-ceramic simplified restorations adhesively cemented to a dentin analogue substrate. Three sets of CAD/CAM burs were used to mill disc-shaped ceramic specimens (1 bur set - 18 milled discs with 10 mm diameter and 1.5 mm thickness), considering the bur experience as a result of the milling sequence to compose the study groups: G1-6 - discs obtained from the 1st to 6th milling of each bur set; G7-12 - specimens from the 7th to 12th milling; G13-18 - discs from the 13th to 18th. Discs of dentin analogue (G10, 10 mm diameter and 2.0 mm thickness) were made to serve as substrate (base material) and randomly assigned into pairs with the respective ceramic discs. Then, the ceramic discs were adhesively cemented onto the dentin analogue substrate, composing a three-layer specimen that mimics a monolithic restoration of a posterior tooth. Specimens were tested under stepwise fatigue approach: frequency = 20 Hz, 5000 cycles at maximum load of 400 N to accommodate the testing assembly, followed by incremental steps of 200 N with initial load ranging from 10 to 1000 N, to a maximum of 20,000 cycles/each step, until the occurrence of failure (radial crack). FFL and CFF were recorded at the end of the testing and subjected to statistical analysis. Supplementary roughness analysis of the milled surface was performed (n = 18) using a contact profilometer. Residual stress after milling and acid etching were accessed via X-ray Diffractometry analysis. FFL and CFF were not affected by increase on bur experience (no statistical differences among groups), despite that, it affected both Ra and Rz parameters (G1-6 had the smoothest surface). The residual stress concentration was negligible (milling did not induce residual stress concentration). It is concluded that the fatigue behavior of adhesively cemented lithium-disilicate glass-ceramic restorations was not influenced by CAD/CAM bur experience (newer vs older as consequence of the milling sequence), and so the residual stress concentration induced by milling was negligible.
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http://dx.doi.org/10.1016/j.jmbbm.2019.04.002DOI Listing
July 2019

Strength of a Zirconia-Reinforced Lithium Silicate Ceramic: Acid-Etching Time and Resin Cement Application Effects.

Int J Periodontics Restorative Dent 2019 May/Jun;39(3):431-437

This study aimed to evaluate the effect of hydrofluoric (HF)-acid-etching time and the impact of a resin-cement layer on the biaxial flexural strength and structural reliability of a zirconia-reinforced lithium silicate (ZLS) glass ceramic. Disc-shaped specimens (n = 15) were divided according to: etching time (conditioning with 10% HF acid for 20, 40, and 60 seconds), and application of a resin-cement layer. Biaxial flexural, contact angle, and roughness analyses were performed. When the resin-cement layer was not present, flexural strength data increased with increasing etching times: 20 seconds = 250.8 MPa; 40 seconds = 278.4 MPa; 60 seconds = 342.9 MPa. Application of resin cement increased the strength values (20 seconds of acid etching on specimens with a resin-cement layer = 341.8 MPa). Different etching times did not affect the roughness of ZLS, and the contact-angle analysis presented lower values for 60 seconds of acid etching. The flexural strength of ZLS was only sensitive to surface changes when less exposure time was conducted. Longer etching times (40 and 60 seconds) should be considered for conditioning ZLS ceramic along with adhesive cementation.
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http://dx.doi.org/10.11607/prd.4117DOI Listing
October 2019

Systematic review of the effects of excessive occlusal mechanical load on the periodontum of rats.

Indian J Dent Res 2018 Nov-Dec;29(6):812-819

Department of Surgery and Integrated Clinics, School of Dentistry, Faculdade de Odontologia, Universidade Estadual Paulista, São Paulo State University, Araçatuba, Brazil.

Objective: This study aims to systematically evaluate the effects of traumatic occlusion on the periodontal tissue of rats. The set of questions to be answered were-Can traumatic occlusion acting on a healthy and an unhealthy periodontium cause periodontal destruction?

Design: The protocols for systematic review were all developed, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement and applied to animal research. Reporting of In vivo experiment guidelines for reporting animal research to assess the risk of bias of the studies.

Materials And Methods: A literature search was conducted using MEDLINE through PubMed and manual search from the reference lists of main articles related to the theme.

Results: This search strategy identified 65 references, of which 33 were considered inappropriate. The full texts of 32 articles were read, 31 of which did not meet the eligibility criteria and were excluded. The final selection included 1 article for which data was extracted for further evaluation. The article included shows a strongest reaction in the periodontium in front of a secondary occlusal trauma as inflammation and apical migration of the junctional epithelium, bone degradation, and decrease in the quantity of collagen fiber. However, primary occlusal trauma also presents these alterations, with the exception of apical migration of the junctional epithelium.

Conclusions: Although only one study was included in the systematic review of traumatic occlusion, there is some evidence from experimental studies on animals that shows a coherent picture of the effects of traumatic occlusion on the periodontium. However, new studies are needed to fully answer the questions posed by this systematic review.
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http://dx.doi.org/10.4103/ijdr.IJDR_31_17DOI Listing
April 2019

Sigmoid Volvulus in Children: Diagnosis and Therapeutic Challenge.

GE Port J Gastroenterol 2018 Sep 6;25(5):264-267. Epub 2018 Feb 6.

Department of Pediatric Surgery, Centro Hospitalar de Vila Nova de Gaia/Espinho, Porto, Portugal.

Background: Sigmoid volvulus is a rare condition in children. Early diagnosis increases the success of nonsurgical treatment in the emergency department, but posterior elective surgery is important due to the risk of recurrence.

Methods/conclusions: We present the case of a healthy 16-year-old girl with recurrent volvulus and successful endoscopic treatment followed by elective surgery.
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http://dx.doi.org/10.1159/000486242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6167736PMC
September 2018

Association between phase angle from bioelectrical impedance analysis and level of physical activity: Systematic review and meta-analysis.

Clin Nutr 2019 08 4;38(4):1504-1510. Epub 2018 Sep 4.

Programa de Pós-graduação em Pediatria e Saúde da Criança, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil; Programa de Pós-graduação em Medicina e Ciências da Saúde da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil; Programa de Pós-graduação em Epidemiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. Electronic address:

Objective: To evaluate the relationship between physical activity and phase angle.

Design: Systematic Review and Meta-analysis.

Data Sources: Electronic searches of MEDLINE (via PUBMED), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), SciELO, LILACS, SPORTDiscus, Scopus, and Web of Science from inception to December 10th, 2017.

Eligibility Criteria For Selecting Studies: The PICOS strategy was defined, in which "P" corresponded to participants of any age, sex or ethnicity, "I" indicated any type of physical activity program, "C" denoted lack of exercise or irregular physical activity, "O" corresponded to the phase angle obtained by bio-impedance, and "S" indicated longitudinal or cross-sectional studies.

Results: In cross-sectional studies the phase angle was higher among the active individuals (MD = 0.70; 95% CI: 0.48, 0.92, P < 0.001), with low heterogeneity (I = 0%; P = 0.619). In longitudinal studies, the mean of the difference of phase angles from the baseline was significantly higher for the active group than the control group (MD = 0.30; 95% CI: 0.11, 0.49, P = 0.001), with low heterogeneity (I = 13%, P = 0.331). No evidence of publication bias was found and the overall risk of bias was moderate to high.

Summary/conclusion: The positive association of physical activity with phase angle reinforces the importance of routinely including exercise in health care. We also identified the need for further studies to define with different types, intensities and frequencies of exercises should be conducted in order to find the best dose-effect relationship.
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http://dx.doi.org/10.1016/j.clnu.2018.08.031DOI Listing
August 2019

Fatigue strength of several dental ceramics indicated for CAD-CAM monolithic restorations.

Braz Oral Res 2018 Jun 11;32:e53. Epub 2018 Jun 11.

Universidade Estadual Paulisa - Unesp, Faculty of Odontology, Department of Dental Materials and Prosthodontics, São José dos Campos, SP, Brazil.

This in vitro study evaluated the fatigue strength of different ceramic materials indicated for monolithic restorations. Disc-shaped specimens were made according to ISO 6872 from five different ceramic materials: feldspathic ceramic (FC), polymer-infiltrated ceramic network (PIC), lithium disilicate glass-ceramic (LD), zirconia-reinforced lithium silicate glass-ceramic (ZLS), and high translucent tetragonal zirconia polycrystals doped by yttrium (YZ-HT). After obtaining the mean of each material (n = 5) from monotonic load-to-failure tests, specimens (n = 20) were subjected to fatigue tests (staircase method) using a biaxial flexural setup (piston-on-three-balls), to determine the fatigue strength. The parameters used for fatigue tests were: 100,000 cycles at 10 Hz, initial load of ~ 60% of mean load-to-failure, and step size of 5% of the initial load (specific for each ceramic material). Kruskal-Wallis and Bonferroni's test (α = 0.05) were used to analyze the fatigue strength data. Fatigue strength (MPa) of the materials was statistically different among each other as follows: YZ-HT (370.2 ± 38.7) > LD (175.2 ± 7.5) > ZLS (152.1 ± 7.5) > PIC (81.8 ± 3.9) > FC (50.8 ± 1.9). Thus, it can be concluded that, in terms of fatigue, high translucent polycrystalline zirconia is the best choice for monolithic restorations as it bears the highest load before cracking/fracturing.
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http://dx.doi.org/10.1590/1807-3107bor-2018.vol32.0053DOI Listing
June 2018

Effect of grinding and aging on subcritical crack growth of a Y-TZP ceramic.

Braz Oral Res 2018 3;32:e32. Epub 2018 May 3.

Post Graduation Program in Dental Science, Prosthetic Dentistry Unit, Universidade Federal de Santa Maria - UFSM, Santa Maria, RS, Brazil.

This study aimed to investigate slow crack growth (SCG) behavior of a zirconia ceramic after grinding and simulated aging with low-temperature degradation (LTD). Complementary analysis of hardness, surface topography, crystalline phase transformation, and roughness were also measured. Disc-shaped specimens (15 mm Ø × 1.2 mm thick, n = 42) of a full-contour Y-TZP ceramic (Zirlux FC, Amherst) were manufactured according to ISO:6872-2008, and then divided into: Ctrl - as-sintered condition; Ctrl LTD - as-sintered after aging in autoclave (134°C, 2 bar, 20 h); G - ground with coarse diamond bur (grit size 181 μm); G LTD - ground and aged. The SCG parameters were measured by a dynamic biaxial flexural test, which determines the tensile stress versus stress rate under four different rates: 100, 10, 1 and 0.1 MPa/s. LTD led to m-phase content increase, as well as grinding (m-phase content: Ctrl - 0%; G - 12.3%; G LTD - 59.9%; Ctrl LTD - 81%). Surface topography and roughness analyses showed that grinding created an irregular surface (increased roughness) and aging did not promote any relevant surface change. There was no statistical difference on surface hardness among different conditions. The control group presented the lowest strength values in all tested rates. Regarding SCG, ground conditions were less susceptible to SCG, delaying its occurrence. Aging (LTD) caused an increase in SCG susceptibility for the as-sintered condition (i.e. G < G LTD < Ctrl < Ctrl LTD).
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http://dx.doi.org/10.1590/1807-3107bor-2018.vol32.0032DOI Listing
May 2018

Effect of polymerization method and fabrication method on occlusal vertical dimension and occlusal contacts of complete-arch prosthesis.

J Adv Prosthodont 2018 Apr 18;10(2):122-127. Epub 2018 Apr 18.

Department of Prosthodontics, Dentistry School, University of Taubaté, Taubaté, SP, Brazil.

Purpose: This study evaluated the dimensional stability of a complete-arch prosthesis processed by conventional method in water bath or microwave energy and polymerized by two different curing cycles.

Materials And Methods: Forty maxillary complete-arch prostheses were randomly divided into four groups (n = 10): MW1 - acrylic resin cured by one microwave cycle; MW2 - acrylic resin cured by two microwave cycles: WB1 - conventional acrylic resin polymerized using one curing cycle in a water bath; WB2 - conventional acrylic resin polymerized using two curing cycles in a water bath. For evaluation of dimensional stability, occlusal vertical dimension (OVD) and area of contact points were measured in two different measurement times: before and after the polymerization method. A digital caliper was used for OVD measurement. Occlusal contact registration strips were used between maxillary and mandibular dentures to measure the contact points. The images were measured using the software IpWin32, and the differences before and after the polymerization methods were calculated. The data were statistically analyzed using the one-way ANOVA and Tukey test (α = .05).

Results: he results demonstrated significant statistical differences for OVD between different measurement times for all groups. MW1 presented the highest OVD values, while WB2 had the lowest OVD values (<.05). No statistical differences were found for area of contact points among the groups (=.7150).

Conclusion: The conventional acrylic resin polymerized using two curing cycles in a water bath led to less difference in OVD of complete-arch prosthesis.
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http://dx.doi.org/10.4047/jap.2018.10.2.122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5917103PMC
April 2018

Histological evaluation of the repair process of replanted rat teeth after storage in resveratrol dissolved in dimethyl sulphoxide.

Dent Traumatol 2018 Apr 14. Epub 2018 Apr 14.

Surgery and Integrated Clinics, Faculdade de Odontologia, UNESP-Universidade Estadual Paulista, Araçatuba, Brazil.

Background/aim: The storage media is directly related to the prognosis of avulsed teeth, with resveratrol drawing attention due to its antioxidant and anti-inflammatory proprieties. The aim of this study was to evaluate the repair process in rat teeth following delayed replantation after storage in resveratrol (R) dissolved in dimethyl sulphoxide (DMSO).

Materials And Methods: The upper right central incisors of 36 rats were divided into 4 groups. In group I, the teeth were extracted and immediately replanted. Group II teeth were stored in 50 mL R+DMSO (0.0512 g/mL), whereas group III teeth were stored in 50 mL pure DMSO, both for a period of 60 minutes. The teeth of group IV were stored dry for 60 minutes. The teeth of groups II, III and IV were then replanted, and the animals were euthanized after 60 days. Longitudinal histological cuts were HE stained for histomorphometric analysis of the periodontal ligament, alveolar bone, cementum and dentin.

Results: The analysis of HE stained histological sections showed the following statistical differences: the acute inflammatory process in the epithelial insertion was less prominent in group II than in group III; the organization of the periodontal ligament was better in group I, while the intensity and extension of acute inflammation in the periodontal ligament were better in group I, and worse in group III; the chronic inflammatory infiltrate was less in groups I and IV, and the depth and extent of resorption, as well as the repair of root resorption, were better in group I.

Conclusions: Storage in R+DMSO solution did not inhibit root resorption after delayed replantation in rat teeth. It is concluded that pure DMSO is not a suitable transport medium for avulsed teeth.
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http://dx.doi.org/10.1111/edt.12402DOI Listing
April 2018

Effect of fatigue protocols on flexural strength of lithium disilicate bars with clamped-ends.

J Mech Behav Biomed Mater 2018 05 10;81:173-177. Epub 2018 Feb 10.

Department of Dentistry, University of Taubaté, Taubaté, São Paulo, Brazil. Electronic address:

The aim of this study was compare the effect of two in vitro ageing protocols to intraoral aging on the flexural strength of a lithium disilicate (LD) ceramic bars with clamped ends. After polishing and crystallization, the both ends of the bars were cemented to a metallic device and subjected to mechanical cycling, thermomechanical cycling, or intraoral ageing. Ten volunteers used an intraoral device - similar to an occlusal splint with a balanced contact condition on the occlusal surface of the ceramic bar - during 8 h night time / 30 days. Both in vitro and intraoral ageing decreased the flexural residual strength of LD, with the lowest values obtained after intraoral ageing. Thus, the in vitro ageing protocols tested in this study revealed to be less deleterious than intraoral ageing of LD.
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http://dx.doi.org/10.1016/j.jmbbm.2018.02.007DOI Listing
May 2018

Immediate tooth replantation: root canal filling for delayed initiation of endodontic treatment.

Braz Oral Res 2018 Mar 1;32:e7. Epub 2018 Mar 1.

Universidade Estadual Paulista - Unesp, School of Dentistry, Surgery and Integrated Clinics, Araçatuba, SP, Brazil.

The aim of this study is to evaluate the action of paramonochlorophenol associated with Furacin followed by calcium hydroxide (CH) dressing in the control of inflammatory root resorption in cases of immediate tooth replantation with delayed endodontic treatment. A total of 28 incisors of 3 male dogs were extracted and replanted after 15 minutes, and randomly divided into 3 groups: Group I (n = 8) - endodontic treatment was performed before the extraction and replantation; Group II (n = 10) - endodontic treatment was performed 30 days after replantation and the root canal was filled with CH dressing; Group III (n = 10) - endodontic treatment was performed 30 days after replantation and root canals received temporary medication of paramonochlorophenol-Furacin followed by CH dressing. The animals were euthanized 90 days after replantation. The histomorphological events analyzed at the epithelial reattachment site were the intensity and extent of acute and chronic inflammatory processes, periodontal ligament (PDL) organization, the intensity and extent of acute and chronic inflammatory processes in the PDL space, root resorption, bone tissue, and ankylosis. Data were submitted to the Wilcoxon Signed Ranks Test for group comparison (α = 5%). In Groups I, II and III the periodontal ligament was regenerated and most of the resorption areas were repaired by newly formed cementum. The depth and extent of root resorption were significantly higher in Group II than in Group III. The use of paramonochlorophenol-furacin followed by CH dressing was more effective in controlling inflammatory root resorption after immediate tooth replantation.
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http://dx.doi.org/10.1590/1807-3107/2018.vol32.0007DOI Listing
March 2018

Influence of plasma-based dry etching on the bond strength of Y-TZP ceramic.

Gen Dent 2018 Mar-Apr;66(2):e11-e15

The aim of this study was to evaluate the bond strength between an yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic and a luting agent when submitted to plasma etching surface treatment before and after thermocycling (TC) with 3000 cycles of 5°C-55°C. The null hypothesis was that the surface treatments and thermocycling would not influence the bond strength. A total of 160 Y-TZP ceramic blocks in 2 sizes (10 size 1 and 10 size 2 blocks in each group) were distributed into 8 groups: group C (control), no surface treatment; group C-TC, TC without prior surface treatment; group SAO, sandblasting with aluminum oxide (Al2O3); group SAO-TC, sandblasting with Al2O3 followed by TC; group SAOS, sandblasting with silica-coated Al2O3; group SAOS-TC, sandblasting with silica-coated Al2O3 followed by TC; group PE, plasma etching; and group PE-TC, plasma etching followed by TC. In each group, size 1 blocks were cemented to size 2 blocks to fabricate specimens for microshear bond strength testing (n = 10 per group). Cementation followed surface treatments (except in control groups) and preceded any TC. All specimens were cemented using a luting agent that contained 10-meth-acryloyloxydecyl dihydrogen phosphate (MDP). The specimens were submitted to a microshear bond strength test and the means were analyzed with a 2-factor analysis of variance and Tukey test. Group PE showed the highest bond strength value before thermocycling (17.31 MPa). After thermocycling, the highest value was observed in the SAO-TC group (9.73 MPa), and statistically significant differences were observed between SAOS-TC and SAO-TC (P < 0.05) and PE-TC and SAO-TC (P < 0.05). Plasma etching improved the bond strength values between the Y-TZP ceramic and MDP-containing luting agent before thermocycling. After thermocycling, all groups showed lower bond strength values.
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January 2019

Effects of Diet on Telomere Length: Systematic Review and Meta-Analysis.

Public Health Genomics 2017 13;20(5):286-292. Epub 2018 Feb 13.

Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.

Background: The goal of this systematic review and meta-analysis is to determine the effect of diet on telomere length.

Methods: We searched the following databases: MEDLINE, Embase, LILACS, CINAHL, ISI Web of Science, and Scopus, as well as the Cochrane Central Register of Controlled Trials and the National Institutes of Health, from inception to December 2016. Articles that assessed effects of diet on telomere length were included.

Results: A total of 2,128 studies were identified, 30 were read in full, and 7 were systematically reviewed. Five RCTs were included in the meta-analysis, covering 9 diets; a total of 533 participants were included. Study heterogeneity (I2) was 89%, and differences were not identified regarding average telomere lengths (mean difference 1.06; 95% CI -1.53 to 3.65).

Conclusion: The available evidence suggests that there is no effect of diet on telomere length, but the strong heterogeneity in the type and duration of dietary interventions does not allow any final statement on the absence of an effect of diet on telomere length.
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http://dx.doi.org/10.1159/000486586DOI Listing
November 2018

Leishmanicidal candidate LASSBio-1736, a cysteine protease inhibitor with favorable pharmacokinetics: low clearance and good distribution.

Xenobiotica 2018 Dec 27;48(12):1258-1267. Epub 2017 Dec 27.

a Programa de Pós-Graduação em Ciências Farmacêuticas , Universidade Federal do Pampa , Uruguaiana , Brazil.

1. LASSBio-1736 ((E)-1-4(trifluoromethyl) benzylidene)-5-(2-4-dichlorozoyl) carbonylhydrazine) is proposed to be an oral cysteine protease leishmanicidal inhibitor. 2. This work aimed to investigate plasma pharmacokinetics, protein binding and tissue distribution of LASSBio-1736 in male Wistar rats. 3. LASSBio-1736 was administered to male Wistar rats at doses of 3.2 mg/kg intravenously and 12.6 mg/kg oral and intraperitoneal. The individual plasma-concentration profiles were determined by HPLC-UV and evaluated by non-compartmental and population pharmacokinetic analysis (Monolix 2016R1, Lixoft). Tissue distribution was evaluated after iv injection of 3.2 mg/kg drug by non-compartmental approach. 4. After intravenous administration, Vd (1.79 L/kg), t (23.1 h) and CL (56.1 mL/h/kg) were determined, and they were statistically similar (α =0.05) to oral and intraperitoneal pharmacokinetic parameters. The plasma profiles obtained after intravenous, oral and intraperitoneal administration of the compound were best fitted to a three-compartment and one-compartment open model with first-order absorption. 5. The intraperitoneal and oral bioavailability were around 40 and 15%, respectively. 6. Liver, spleen and skin tissues showed penetration of 340, 130 and 40%, respectively, with t like plasma values. 7. LASSBio-1736 protein binding was 95 ± 2%. 8. The t , CL and tissue distribution of the compound agreed with the desired drug characteristics for leishmanicidal activity.
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http://dx.doi.org/10.1080/00498254.2017.1405465DOI Listing
December 2018
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