Papers by Paulo Vinícius Soares
Journal of dental education, 2013
On the --
Dental Materials, 2011
d e n t a l m a t e r i a l s 2 7 S ( 2 0 1 1 ) e1-e84
Journal of Endodontics, 2014
Introduction: The aim of this study was to evaluate the influence of post system, length, and fer... more Introduction: The aim of this study was to evaluate the influence of post system, length, and ferrule on biomechanical behavior of endodontically treated anterior teeth. Methods: The investigation was conducted by using laboratory tests and 3-dimensional finite element analysis. Eighty bovine incisors were selected and divided into 8 treatment groups (n = 10) with absence of ferrule and 2.0 mm of ferrule, restored with glass fiber post or cast post and core, and 12.0 and 7.0 mm of post length. The specimens were loaded at 135 angle, and the strain was measured by using strain gauge method. Specimens were subsequently loaded until fracture. Strain and fracture resistance results were analyzed by 3-way analysis of variance and Tukey honestly significant difference tests (a = 0.05). Three-dimensional models of a maxillary central incisor were generated with the same treatment variations used in laboratory tests. Each model was subjected to 100 N oblique loads. Results were evaluated by von Mises criterion. Results: Ferrule was a determining factor in the strain, fracture resistance, and fracture pattern. In the absence of ferrule, the use of fiberglass posts represents a conservative choice from the standpoint of the fracture patterns observed. The length of 7 mm for cast post and cores produced high rates of root fractures. Finite element analysis showed that glass fiber post showed homogeneous stress distribution, whereas cast post showed stress concentration into root canal. Conclusions: Post length influenced only the cast post strain and stress distribution. The ferrule groups always showed more satisfactory stress distribution and fracture resistance. (J Endod 2014;40:119-123)
Brazilian Oral Research, 2013
The aim of this study was to evaluate the effect of parallel and tapered threaded post placement ... more The aim of this study was to evaluate the effect of parallel and tapered threaded post placement on the strain and stress distribution of endodontically treated teeth. Fifteen bovine incisors were sectioned 15 mm from their apices, endodontically treated, and divided into three groups (n = 5) according to three different threaded posts: parallel threaded post (Radix-Anker, RA); tapered threaded post (Euro-Post, EP) and tapered threaded post (Reforpost II, RII). A strain-gauge was fixed on the proximal surface perpendicular to the long root axis, 2 mm from the cervical limit. Strain generated during post placement was recorded and compared using one-way ANOVA and Tukey's test (α = .05). A scanning electron microscope was used to examine the longitudinal root sections. Stress was evaluated for each group in a two-dimensional finite element analysis. The models were meshed with tetrahedron elements and loaded with 2 N at an angle of 135° to the lingual face. The equivalent Von Mises stress was calculated. The one-way ANOVA showed significant difference among the groups. The RA group (150.0 ± 12.2 A) produced higher external strain than the RII (80.0 ± 12.2 B) and the EP (70.0 ± 6.1 B) groups. The inner strain was approximately five times greater than the external dentin strain. High stress concentrations in each thread of the posts were observed. Scanning electron micrographs showed cracks that started in the threads of the posts. The threaded post placement induced root strain mainly on the parallel side post. Root strain and stress concentration on the post threads tended to create cracks in the inner root canal dentin.
Clinical oral investigations, 2006
The aim of this study was to determine the radiodensity of base, liner and luting dental material... more The aim of this study was to determine the radiodensity of base, liner and luting dental materials and to compare them with human enamel and dentin. Four classes of materials were examined: conventional glass ionomers (CG)-Vitro Cem, Ketac Bond, Vidrion F, Vidrion C; resinmodified glass ionomers (RMGI)-Fuji II LC, Vitrebond; resinous cement (RC)-Rely-X ARC; and zinc phosphate cement (ZP)-Cimento LS. Five 2-mm-thick standard samples of each material and five 2-mm-thick enamel and dentin samples were produced. An aluminum step wedge served as control. Samples were positioned over a phosphor plate of Digora digital system, exposed to X-ray, and the radiodensity obtained in the software Digora for Windows 2.0. Data were submitted to Kruskal-Wallis and Dunnett multiple comparisons test (α=0.05). According to statistical analysis, the following sequence in degree of radiodensity could be seen among the groups: Cimento LS (ZP) > Vitro Cem (CG) = Fuji II LC (RMGI) = Rely-X ARC (RC) = Vitrebond (RMGI) > Ketac Bond (CG) > enamel = Vidrion F (CG) > Vidrion C (CG) = dentin. The presence of radiopaque fillers such as zinc, strontium, zirconium, barium, and lanthanium rather than material type seems to be the most important factor when analyzing material radiodensity. Almost all investigated materials presented an accepted radiodensity.
Journal of prosthodontics : official journal of the American College of Prosthodontists, 2010
To test the hypothesis that the type of cement used for fixation of cast doweland-cores might inf... more To test the hypothesis that the type of cement used for fixation of cast doweland-cores might influence fracture resistance, fracture mode, and stress distribution of single-rooted teeth restored with this class of metallic dowels. Materials and Methods: The coronal portion was removed from 40 bovine incisors, leaving a 15 mm root. After endodontic treatment and standardized root canal relief at 10 mm, specimens were embedded in polystyrene resin, and the periodontal ligament was simulated with polyether impression material. The specimens were randomly divided into four groups (n = 10), and restored with Cu-Al cast dowel-and-cores cemented with one of four options: conventional glass ionomer cement (GI); resinmodified glass ionomer cement (GR); dual-cure resin cement (RC); or zinc-phosphate cement (ZP). Sequentially, fracture resistance of the specimens was tested with a tangential load at a 135 • angle with a 0.5 mm/min crosshead speed. Data were analyzed using one-way analysis of variance (ANOVA) and the Fisher test. Two-dimensional finite element analysis (2D-FEA) was then performed with representative models of each group simulating a 100 μm cement layer. Results were analyzed based on von Mises stress distribution criteria. Results: The mean fracture resistance values were (in N): RC, 838.2 ± 135.9; GI, 772.4 ± 169.8; GR, 613.4 ± 157.5; ZP, 643.6 ± 106.7. FEA revealed that RC and GR presented lower stress values than ZP and GI. The higher stress concentration was coincident with more catastrophic failures, and consequently, with lower fracture resistance values. Conclusions: The type of cement influenced fracture resistance, failure mode, and stress distribution on teeth restored with cast dowel-and-cores.
Revista Brasileira de Educação Física e Esporte, 2014
In time where the words of Baron de Coubertin " e important thing in life is not the triumph but ... more In time where the words of Baron de Coubertin " e important thing in life is not the triumph but the struggle" to improve the athlete's performance was not as much meaning these days where the important thing is to win. Depending on the sport practiced, milliseconds can make the podium and the health of the athlete now has vital importance. For this there was a great incentive for research to bring improvement in athletic performance, talent detection, care that result in breaking records, medals and trophies. With the results of these surveys Clubs, Associations and Institutions started to give due consideration to performance of their athletes thus providing its professional sta involved in the day to day of these in physiology, biomechanics, game analyst, nutritionists, physiotherapists, psychologists, doctors and dentists currently. e role of dentistry in the sports is important, because it provides the athlete optimal oral health conditions which in turn can contribute to achievement of optimal performance during competitions. Sports Dentistry (SD) involves the prevention, maintenance and treatment of oral and facial injuries, as well as the collection and dissemination of information on dental trauma, in addition to stimulating research 1 . It directs a duty of the dentist detect problems of the athlete, such as mouth breathing, poor positioning of the arches, and properly administer medications free of substances, that may provide the positive doping present in many painkillers. e SD is still recent in Brazil, and the Federal Council of Dentistry (FCD) does not recognize the SD as a specialty and it is not included as a compulsory subject in the curriculum o ered at most universities.
Quintessence international (Berlin, Germany : 1985), 2014
Because of their predictable results and conservation of tooth structure, ceramic veneers are ind... more Because of their predictable results and conservation of tooth structure, ceramic veneers are indicated for the esthetic treatment of anterior teeth with anomalous positions or appearance. The objective of this case report is to highlight the steps in dental rehabilitation using ceramic veneers reinforced by lithium disilicate. In this case the patient had diastemas between the mandibular incisors. After preliminary proced-ures, diagnostic models, waxing, and mock-up were completed, an impression was made with addition silicone, and the veneers were fabricated and cemented with light-cure cement. As a result, the esthetics and function expected by the patient were achieved. The use of ceramic veneers enabled a conservative and esthetically successful rehabilitation treatment.
Australian dental journal, Jan 13, 2014
Loading and composite restoration assessment of different non-carious cervical lesions morphologi... more Loading and composite restoration assessment of different non-carious cervical lesions morphologies -3D Finite Element Analysis Short running title: Biomechanical behavior of NCCLs geometry (i) Abstract:
International Journal of Experimental Dental Science, 2012
This study evaluated the effect of adhesive application only to enamel on the gap formation of co... more This study evaluated the effect of adhesive application only to enamel on the gap formation of composite resin restorations performed with different adhesive systems and submitted to mechanical cycling. Standardized cylinder-shaped cavities were prepared on the buccal surface of 60 bovine incisors. Two etchand-rinse [Adper Scotchbond Multi-purpose (3M ESPE, St. Paul, MN, USA) and Adper Single Bond 2 (3M ESPE)] and one selfetching [Clearfil SE Bond (Kuraray, Osaka, Japan)] adhesive systems were evaluated. The adhesives were applied only to enamel or to both dentin and enamel. After adhesive light activation, the cavities were restored with composite resin. The restorations were finished and polished; the marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500× magnification) in low-vacuum mode. After the first evaluation, the samples were submitted to mechanical cycling (300,000 cycles of 80 kN and 1.5 Hz) and a new evaluation was performed. There was observed any gap for all experimental conditions before and after mechanical cycling. Bonding to dentin does not alter the marginal adaptation of composite restorations.
Dental Materials, 2008
This study tested the hypothesis that the stress distribution and bond strength of glass posts to... more This study tested the hypothesis that the stress distribution and bond strength of glass posts to intraradicular dentin is influenced by the mechanical testing methodology.Thirty single rooted endodontically treated teeth were prepared for luting of tapered fiber-glass posts (Reforpost, Angelus, Londrina, PR, Brazil) with a conventional adhesive system and resin luting cement (Adper Scotchbond Multi-purpose, Rely X ARC, 3M ESPE, St. Paul, MN, USA). The teeth were randomly divided (n = 10 per group) into micro-push-out (Mpo), hourglass- (Mh) and rectangular stick-shaped (Ms) microtensile testing groups before sectioning each root into five 1-mm-thick specimens. During specimen preparation for μTBS testing 46/50 stick and 4/50 hourglass specimens prematurely failed; therefore, the Ms group could not be included in the mechanical testing. The remaining specimens were tested at 0.5 mm/min until bond failure. Stress distribution within each specimen type for the three mechanical test methods was analyzed by finite element analysis (FEA). Qualitative analyses were carried out through Von Mises, XY and Sy criterion.Mpo and Mh had a mean μTBS of 11.89 ± 6.55 and 14.98 ± 12.72 MPa, respectively, which was not significantly different (p = 0.1311). The push-out test demonstrated a more homogenous stress distribution by FEA and less variability in mechanical testing.Therefore, the recommended testing method for determining the bond strength of glass posts to intraradicular dentin is by Mpo.
Journal of Endodontics, 2011
Etching is necessary to expose the fibers and enable both mechanical and chemical bonding of the ... more Etching is necessary to expose the fibers and enable both mechanical and chemical bonding of the resin core to the fiber post. This study evaluated the effect of concentration and application time of hydrogen peroxide on the surface topography and bond strength of glass fiber posts to resin cores.Fiber posts were etched with 24% or 50% hydrogen peroxide for 1, 5, or 10 min (n = 10). Posts without any treatment were used as a control. After etching, the posts were silanated and adhesive resin was applied. The posts were positioned into a mold to allow a self-cured resin core to be inserted. The post/resin assembly was serially sectioned into five beams that were subjected to a tensile bond strength test. Data were subjected to two-way ANOVA and Tukey test (α = 0.05). The surface topography was analyzed using scanning electronic microscopy.Non-etched post presents a relatively smooth surface without fiber exposure. Application of hydrogen peroxide increased the surface roughness and exposed the fibers. All experimental conditions yielded similar bond strength values that were higher than those obtained in the control group.Both 24% and 50% hydrogen peroxide exposure increased the bond strength of resin to the posts, irrespective of the application time.
Journal of Prosthodontics, 2011
Purpose: This in vitro study investigated the null hypothesis that metal-free crowns induce fract... more Purpose: This in vitro study investigated the null hypothesis that metal-free crowns induce fracture loads and mechanical behavior similar to metal ceramic systems and to study the fracture pattern of ceramic crowns under compressive loads using finite element and fractography analyses. Materials and Methods: Six groups (n = 8) with crowns from different systems were compared: conventional metal ceramic (Noritake) (CMC); modified metal ceramic (Noritake) (MMC); lithium disilicate-reinforced ceramic (IPS Empress II) (EMP); leucite-reinforced ceramic (Cergogold) (CERG); leucite fluoride-apatite reinforced ceramic (IPS d.Sign) (SIGN); and polymer crowns (Targis) (TARG). Standardized crown preparations were performed on bovine roots containing NiCr metal dowels and resin cores. Crowns were fabricated using the ceramics listed, cemented with dual-cure resin cement, and submitted to compressive loads in a mechanical testing machine at a 0.5-mm/min crosshead speed. Data were submitted to one-way ANOVA and Tukey tests, and fractured specimens were visually inspected under a stereomicroscope (20×) to determine the type of fracture. Maximum principal stress (MPS) distributions were calculated using finite element analysis, and fracture origin and the correlation with the fracture type were determined using fractography. Results: Mean values of fracture resistance (N) for all groups were: CMC: 1383 ± 298 (a); MMC: 1691 ± 236 (a); EMP: 657 ± 153 (b); CERG: 546 ± 149 (bc); SIGN: 443 ± 126 (c); TARG: 749 ± 113 (b). Statistical results showed significant differences among groups (p < 0.05) represented by different lowercase letters. Metal ceramic crowns presented fracture loads significantly higher than the others. Ceramic specimens presented high incidence of fractures involving either the core or the tooth, and all fractures of polymer crown specimens involved the tooth in a catastrophic way. Based on stress and fractographic analyses it was determined that fracture occurred from the occlusal to the cervical direction. Conclusions: Within the limitations of this study, the results indicated that the use of ceramic and polymer crowns without a core reinforcement should be carefully evaluated before clinical use due to the high incidence of failure with tooth involvement. This mainly occurred for the polymer crown group, although the fracture load was higher than normal occlusal forces. High tensile stress concentrations were found around and between the occlusal loading points. Fractographic analysis indicated fracture originating from the load point and propagating from the occlusal surface toward the cervical area, which is the opposite direction of that observed in clinical situations.
Journal of Prosthodontics, 2008
The aim of this study was to evaluate the effect of endodontic and restorative treatment on the f... more The aim of this study was to evaluate the effect of endodontic and restorative treatment on the fracture resistance of posterior teeth. Materials and Methods: Fifty intact premolars were selected and randomly placed into five groups (n = 10): G1, intact teeth (control); G2, mesial-occlusal-distal (MOD) preparation; G3, MOD preparation restored with composite resin (Z-250, 3M ESPE); G4, MOD preparation and endodontic treatment; and G5, MOD preparation, endodontic treatment, and composite resin restoration. The specimens were submitted to an axial compression load in a mechanical test machine (EMIC), at a speed of 0.5 mm/min. Fracture patterns were analyzed at four levels. Five 2D numerical models were created by Ansys 10.0 for finite element analysis (FEA). Results: Mean values of compressive strength for all groups were (Kgf): G1 (83.6 ± 25.4); G2 (52.7 ± 20.2); G3 (82.1 ± 24.9); G4 (40.2 ± 14.2); G5 (64.5 ± 18.1). Statistical analysis (ANOVA and Tukey's test) showed that fracture resistance of G1 was significantly higher than that of G5, G2, and G4. Resistance of G3 was also higher than that of G2 and G4. Results showed that the tooth resistance is completely maintained when MOD preparation is restored with composite resin and partially recovered when MOD preparation associated with an endodontic access is restored in the same way. The endodontic treatment and composite resin restoration influenced stress distribution in the dental structure. Conclusions: Composite resin restoration plays an important role in recovering tooth strength. With regard to fracture mode, restoration and endodontic treatment increased the incidence of periodontal involvement, which was demonstrated by association with the finite element mechanical test method.
The Journal of Prosthetic Dentistry, 2008
The Journal of Prosthetic Dentistry, 2008
International Endodontic Journal, 2010
Raposo LHA, Silva GR, Santos-Filho PCF, Soares PV, Soares PBF, Simamoto-Junior PC, Fernandes-Neto... more Raposo LHA, Silva GR, Santos-Filho PCF, Soares PV, Soares PBF, Simamoto-Junior PC, Fernandes-Neto AJ, Soares CJ. Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and-cores. International Endodontic Journal.Raposo LHA, Silva GR, Santos-Filho PCF, Soares PV, Soares PBF, Simamoto-Junior PC, Fernandes-Neto AJ, Soares CJ. Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and-cores. International Endodontic Journal.AbstractAim To test the hypothesis that the presence of an anti-rotation device (ARD) and its location can influence the biomechanical behaviour of root filled teeth restored with cast post-and-cores and metallic crowns.Methodology Fifth two bovine incisor roots were selected and divided into four groups (n = 13): Nd- without ARD; Bd- buccal ARD; Ld- lingual ARD; BLd- buccal and lingual ARD. The specimens were restored with cast post-and-cores and metallic crowns. After a fatigue process (3 × 105 50 N), three strain gauges were attached on the buccal, lingual and proximal surfaces and the samples of each group (n = 3) were submitted to a 0–100 N load. Fracture resistance was assessed in a mechanical testing machine (n = 10). Strain values and fracture resistance data were analysed by one-way anova and Tukey Honestly Significant Difference (HSD) test (α = 0.05). The failure mode was then evaluated under an optical stereomicroscope. Bidimensional models of each group were generated for finite element analysis (FEA) and analysed using the von Mises criteria.Results No significant difference in fracture resistance values and fracture modes occurred between the four groups. The BLd group had higher stress concentrations in the buccal dentine and higher strain values on the proximal surfaces.Conclusions The anti-rotation devices did not influence significantly the fracture resistance and fracture mode. However, the stress–strain values were increased when the anti-rotation device was prepared on the buccal and lingual faces concomitantly.Aim To test the hypothesis that the presence of an anti-rotation device (ARD) and its location can influence the biomechanical behaviour of root filled teeth restored with cast post-and-cores and metallic crowns.Methodology Fifth two bovine incisor roots were selected and divided into four groups (n = 13): Nd- without ARD; Bd- buccal ARD; Ld- lingual ARD; BLd- buccal and lingual ARD. The specimens were restored with cast post-and-cores and metallic crowns. After a fatigue process (3 × 105 50 N), three strain gauges were attached on the buccal, lingual and proximal surfaces and the samples of each group (n = 3) were submitted to a 0–100 N load. Fracture resistance was assessed in a mechanical testing machine (n = 10). Strain values and fracture resistance data were analysed by one-way anova and Tukey Honestly Significant Difference (HSD) test (α = 0.05). The failure mode was then evaluated under an optical stereomicroscope. Bidimensional models of each group were generated for finite element analysis (FEA) and analysed using the von Mises criteria.Results No significant difference in fracture resistance values and fracture modes occurred between the four groups. The BLd group had higher stress concentrations in the buccal dentine and higher strain values on the proximal surfaces.Conclusions The anti-rotation devices did not influence significantly the fracture resistance and fracture mode. However, the stress–strain values were increased when the anti-rotation device was prepared on the buccal and lingual faces concomitantly.
Journal of Prosthodontics, 2009
Purpose: The degree of stress generated in the endodontically treated and restored tooth can be i... more Purpose: The degree of stress generated in the endodontically treated and restored tooth can be influenced by the composition and configuration of the dowels used for the restoration. Using two-dimensional (2D) finite element analysis (FEA), this study tested the hypothesis that the characterization of the stress distribution can be influenced by which evaluation method is employed: protrusion loading and 4-point flexural strength test or varying the type of material (carbon and glass fiber) or the external configuration of the dowel (smooth and serrated).Materials and Methods: For simulation of the protrusion load test, models were generated with Mechanical-AutoCAD V6 software from an image of an anatomical plate, one maxillary central incisor, and two dowels and exported to Ansys 9.0. The bone region model was fixed, and a tangential load of 1 N with a 135° inclination to the tooth longitudinal axis was applied at the level of the palatal surface of the crown. In the simulation of a 4-point flexural strength test, a 1 N perpendicular load was applied in two points to the dowel. The dental materials and structures were considered elastic, isotropic, homogeneous, and linear, with the exception of the dowel, which was assumed to exhibit orthotropic behavior. Mechanical properties were defined based on a review of the literature, and the model was meshed with an eight node tetrahedral element.Results: The stress results from both tests were analyzed according to von Mises criteria and principal stresses (Sx). Data from the 4-point flexural strength test simulation showed that, for the serrated dowels, a higher stress concentration was found; however, no difference in the occlusal load for material or dowel configuration was found.Conclusions: These results suggest that although the external configuration of the dowel influences direct loading, when the dowel is integrated to the tooth and setting material, the influence on biomechanical behavior disappears.
Journal of Dental Research, 2010
The effect of gamma irradiation therapy on the ultimate tensile strength (UTS) of enamel and dent... more The effect of gamma irradiation therapy on the ultimate tensile strength (UTS) of enamel and dentin in relation to prism orientation, dentin tubule orientation, and location is unknown. It was hypothesized that tubule and prism orientation, location, and irradiation have an effect on the UTS of dental structures. Forty human third molars were used, half of which were subjected to 60 Gy of gamma irradiation, in daily increments of 2 Gy. The specimens were evaluated by microtensile testing. Results showed that irradiation treatment significantly decreased the UTS of coronal and radicular dentin and of enamel, regardless of tubule or prism orientation. With or without irradiation, enamel was significantly stronger when tested parallel to its prismatic orientation. Coronal and radicular dentin of non-irradiated specimens presented significantly higher UTS when tested perpendicularly to tubule orientation. However, when the teeth were irradiated, the influence of tubule orientation disappeared, demonstrating that irradiation is more harmful to organic components.
Journal of Prosthetic Dentistry, 2008
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Papers by Paulo Vinícius Soares