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Am J Dent ; 32(5): 215-218, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31675187


PURPOSE: To evaluate the influence of the Er,Cr:YSGG laser with or without the 5% fluoride varnish on the acid resistance of dentin after erosive challenge. METHODS: 36 incisors were selected and sectioned, obtaining 72 specimens of 4 mm × 4 mm and randomly divided into eight groups (n = 9). In G1: application of Er,Cr:YSGG (0.1W; 5Hz, air 55%); G2: laser (0.25W; 5Hz, air 55%); G3: fluoride varnish + laser (0.1W; 5Hz, air 55%); G4: fluoride varnish + laser (0.25W, 5Hz, air 55%); G5: fluoride varnish + laser (0.1W; 5Hz, without air); G6: fluoride varnish + laser (0.25W, 5Hz, without air); G7: fluoride varnish and G8: no treatment. When used, the laser was irradiated without water cooling, scanning mode during 10 seconds. The surface roughness data were subjected to ANOVA. For wear profile, we used Kruskal-Wallis test and Dunn post-hoc, all with α= 0.05. RESULTS: The results showed no statistically significant difference when comparing the groups as regards to the surface roughness (P> 0.05). Regarding the percentage of lost volume, the G5 and G6 groups presented the best results (G5 = 7.8% and G6 = 8.5%), with the lowest loss of dentin volume compared to other groups (P< 0.05). The G8 group (no treatment) had the highest lost volume (G8 = 39.1% followed by the G7 group (fluoride varnish), which had 25.9%. CLINICAL SIGNIFICANCE: The use of Er,Cr:YSGG laser and fluoride varnish can be an effective method to increase the acid resistance of dentin after erosive challenges, and limit problems related to hypersensitivity.

Lasers de Estado Sólido , Ácidos , Dentina , Fluoretos
Dent Traumatol ; 35(4-5): 276-284, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31054190


BACKGROUND/AIM: Maxillary canines have a high incidence of impaction which may be associated with unexpected damage during maxillofacial trauma. The aim of this study was to evaluate how an impacted canine could influence the stress distribution in the dentoalveolar complex during a simulated impact before and after surgical removal plus the protective effect offered by a mouthguard. MATERIALS AND METHODS: Cross-sectional finite element models of the central incisor and support structures of a patient with an impacted canine in a transverse position were made using ImageJ and Marc/Mentat software. The following impact conditions were simulated: (a) incisor with impacted canine; (b) incisor with surgical socket after impacted canine extraction; and (c) incisor after bone healing. The impacts were also simulated with a 3 mm custom-fitted ethylene vinyl acetate mouthguard. A non-linear dynamic impact finite element analysis was performed in which a rigid object hit the model at 1 m/s. Maximum and minimum principal stresses as well as von Mises stresses were analyzed. RESULTS: Higher values of compressive and tensile stresses occurred on the cortical bone in the models after impacted canine extraction. The highest stress concentrations in the enamel and dentin structures were observed after bone healing. The mouthguard reduced the stress in the alveolar bone and dental structures. CONCLUSIONS: Use of mouthguards during impact reduced the compressive and tensile stresses in the alveolar bone, mainly in the fragile regions of the impacted canine or surgical socket.

Análise do Estresse Dentário , Protetores Bucais , Traumatismos Dentários , Dente Impactado , Fenômenos Biomecânicos , Estudos Transversais , Desenho de Equipamento , Análise de Elementos Finitos , Humanos , Maxila
Quintessence Int ; 50(5): 350-356, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30957110


OBJECTIVE: The objective was to evaluate the effects of the configuration of endodontic cavities with parallel or divergent walls, versus traditional endodontic cavities, on stress distribution, fracture resistance, and fracture mode of maxillary premolars by using both fracture-strength and finite element tests. METHOD AND MATERIALS: Thirty-two maxillary first premolars were divided into four groups (n = 8), according to the type of endodontic cavities: without endodontic cavities (control); conservative; conservative with diverging walls; and traditional. After performing root canal treatment and restoration, fracture resistance was evaluated by oblique compressive load. The stress distribution was evaluated by nonlinear finite element analysis by means of micro-computed tomography, operated at 50 kV and 800 mA. The fracture resistance data were analyzed by statistical software. RESULTS: Higher stress concentration was observed on the coronal portion of the palatal cusp and the palatal root dentin. Stress concentration on the palatal root dentin was similar for all groups. The stress level on the palatal cusp and at the proximal crests was slightly increased in the traditional endodontic cavities group compared with conservative endodontic cavities. Stress distribution in restored teeth was similar to that of intact teeth. No significant differences were observed in the fracture resistance among different endodontic cavities' design (P = .32). All groups had values similar to those of the control group (P > .05). CONCLUSIONS: Regardless of the cavity design, conservative endodontic cavities that preserve marginal ridge integrity did not affect the resistance to fracture, failure mode, or stress distribution in maxillary premolars restored with composite resin. Endodontically treated teeth displayed biomechanical behavior similar to sound teeth.

Fraturas dos Dentes , Dente não Vital , Dente Pré-Molar , Resinas Compostas , Preparo da Cavidade Dentária , Restauração Dentária Permanente , Análise do Estresse Dentário , Humanos , Microtomografia por Raio-X
J Prosthet Dent ; 121(5): 868.e1-868.e8, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31010591


STATEMENT OF PROBLEM: Posterior composite restorations may be negatively affected by acidic and colored drinks. Little information is available about the effect of acidic drinks on bulk-fill composite resins. PURPOSE: The purpose of this in vitro study was to investigate the effect of acidic drinks on the different properties of conventional and bulk-fill composite resins. MATERIAL AND METHODS: A conventional composite resin and 2 representative bulk-fill composite resins were used to prepare disk-shaped specimens. The degree of conversion (DC) was monitored by spectroscopy (n=5). The specimens were divided into 5 groups: control, artificial saliva, acai juice, red wine, and Coca-Cola and were maintained for 30 days of challenge (3 periods of 15 min/d). Surface topography parameters were measured by interferometry (n=5). Elastic modulus (E) and Vickers hardness (VH) were determined by microhardness dynamic indentation (n=5). Diametral tensile strength (DTS) was determined at 0.5 mm/min (n=5). Shade matching was evaluated by using the Vitapan Classic Shade Guide. The DC, Sa, Ssk, Sku, Sdq, and DTS were statistically analyzed using 2-way ANOVA, followed by the Tukey HSD tests. E and VH were statistically analyzed by 3-way ANOVA, followed by Tukey HSD tests (α=.05). Shade matching was analyzed with the Kruskal-Wallis test. RESULTS: DC values were similar for the immediate evaluation and after 24 hours, regardless of the composite resin (P<.05). All surface topography parameters increased significantly after the acidic drinks and were greatest for Coca-Cola. The E, VH, and DTS decreased significantly for all composite resins tested (P<.05). Acai juice and red wine produced more surface staining than Coca-Cola. CONCLUSIONS: Acidic drinks negatively influenced the physical and mechanical properties of conventional and bulk-fill composite resins.

Bebidas Gaseificadas , Resinas Compostas , Módulo de Elasticidade , Dureza , Teste de Materiais , Propriedades de Superfície , Resistência à Tração
J Adhes Dent ; 21(1): 37-46, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30799470


PURPOSE: To evaluate the method of resin cement mixing and insertion into the root canal on resin cement porosity and fiberglass-post push-out bond strength (PBS). MATERIALS AND METHODS: One hundred twenty human single-rooted teeth were sectioned to a length of 15 mm, en-do-dontically filled, and received a fiberglass post cemented with 3 self-adhesive resin cements (RelyX U200, seT, Panavia SA) using 4 mixing methods/insertion techniques (handmix/endodontic file, handmix/Centrix syringe, automix/conventional tip, automix/endo tip). The samples were scanned using micro-CT. Two slices from the cervical, middle, and apical thirds were submitted to push-out bond strength (PBS) testing, and failure modes were classified. The PBS, volume of resin cement, and porosity data were analyzed using ANOVA and Tukey's test. RESULTS: The porosity was lowest in the cervical third and highest in the apical third, irrespective of the resin cement. The porosity was lower in the the automix/endo tip group compared to the handmix/endodontic file group. The use of Centrix or endo tip reduced the porosity and increased the PBS in the apical third compared with the use of endodontic files. The root canal depth reduced the PBS for U200 and seT when handmix/endodontic files were used. U200 and seT using the automix method increased the PBS, thus eliminating the effect of root region, irrespective of the insertion technique. In general, U200 showed higher PBS and Panavia lower PBS. Adhesive failure between root dentin and resin cement was predominant. CONCLUSIONS: Automixing the cement and using an endo tip produces fewer voids and increased the bond strengths.

Colagem Dentária , Técnica para Retentor Intrarradicular , Cavidade Pulpar , Dentina , Vidro , Humanos , Teste de Materiais , Porosidade , Cimentos de Resina
Dent Traumatol ; 35(2): 128-134, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30466155


BACKGROUND/AIMS: Dental trauma is the cause of several consequences to the injured tooth. However, the stresses and strains at adjacent teeth non-directly impacted as a possible cause of sequelae are still unknown. The aim of this study was to evaluate the stress distribution in incisors adjacent to an upper central incisor when it suffers a frontal impact in order to identify a potential explanation for sequelae in non-traumatized teeth. MATERIALS AND METHODS: A three-dimensional (3D) finite element model of the maxillary central incisors, lateral incisors and canines was created from a cone-beam scan of a patient with normal occlusion. Non-linear dynamic impact analysis was performed, simulating the right central incisor being impacted by a steel ball with a velocity of 10 m/s. A functional chewing load (100 N) on the palatal surface of the central incisor was simulated for comparison. Displacements, strains and modified von Mises stresses were calculated for the adjacent teeth. RESULTS: During impact on the central incisor, the adjacent teeth showed root displacement. Considerable stress concentrations were observed on the palatal surfaces, proximal and labial surfaces of teeth adjacent to the traumatized incisor. Stresses in the adjacent teeth were higher than stresses calculated during functional biting. Compressive stresses were concentrated at the proximal areas of the adjacent incisors. High levels of deformation were found in the root dentin of adjacent teeth during the traumatic event. CONCLUSIONS: A frontal impact on an anterior tooth generated stresses at the roots of adjacent teeth. These stresses may play a role in clinically observed sequelae of teeth adjacent to traumatized teeth.

Análise do Estresse Dentário , Análise de Elementos Finitos , Incisivo , Traumatismos Dentários , Humanos
Dent Traumatol ; 35(2): 101-108, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30561893


BACKGROUND/AIM: Dental trauma is a common emergency in children with primary teeth. The aim of this study was to determine stress propagation to the permanent tooth germ and surrounding bone and soft tissues during dental trauma to primary central incisors with three levels of physiological root resorption. MATERIAL AND METHODS: Stresses were determined using finite element analysis (FEA). Cross-sectional models were created using cone-beam computed tomography images of 3.5, 5, and 6 years olds, representing three different physiological root resorption stages of a maxillary primary central incisor. The models included periodontal ligament, bone, and soft tissues. An impact with an asphalt block moving at 1 m/s,was simulated for two impact two directions, frontal on the labial tooth surface, and on the incisal edge. Stresses and strains were recorded during impact. RESULTS: The impact caused stress concentrations in the surrounding bone and soft tissues and permanent tooth germ, regardless of the direction of impact and the primary tooth resorption stage. Impact stresses in dental follicles and surrounding bone increased in models with more physiological root resorption of the primary tooth. Incisal impact generated higher stress concentrations in surrounding bone and soft tissues and permanent tooth germ regardless of physiological root resorption stage. The primary incisor with no physiological root resorption showed high stress concentrations at its root apex. CONCLUSION: During impact to a primary incisor, stresses most significant for potential damage to the formation of permanent enamel and dentin were at the dental follicle and surrounding bone tissue with the three levels of physiological root resorption.

Análise de Elementos Finitos , Reabsorção da Raiz , Germe de Dente , Dente Decíduo/lesões , Criança , Estudos Transversais , Humanos , Maxila , Raiz Dentária
PLoS One ; 13(9): e0203284, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30231035


This study investigated the use of scientific evidence and the practice of evidence-based dentistry (EBD) among dentists working in Brazil. An online questionnaire was emailed to dentists registered with Brazilian state dental councils. The questionnaire assessed the demographic, educational, and work characteristics of the sample, along with habits in reading scientific articles and other updating resources. Data were analyzed descriptively and by using Bonferroni, Kruskal-Wallis, ANOVA, and T-test statistical methods (α = 0.05). A total of 795 responses were received between June, 2015 and January, 2016. The response rate was not calculated because it was not possible to determine precisely how many dentists received these e-mails. Over 77% of the responding dentists completed postgraduate training. They referred mainly to books, scientific or clinical journals, conferences, and short-term courses for updating their knowledge. Dentists who reported having a habit of reading scientific journals (60.9%) showed a preference for reading case reports, clinical research articles, and literature reviews. Most dentists (77.5%) reported changing their clinical behaviors or procedures based on information gleaned from journal articles. The types of articles that led them to change their clinical practices were primarily clinical research articles and case reports. Working in the public sector was also associated with a lower prevalence of a habit of reading scientific journals and practicing EBD (i.e., self-reported practice). The results suggest that dentists are interested in reading journal articles, especially those addressing clinical outcomes, and that there is room for improving the practice of EBD, particularly in the public sector.

Odontologia Baseada em Evidências , Atitude do Pessoal de Saúde , Brasil , Odontólogos , Odontologia Baseada em Evidências/educação , Feminino , Humanos , Masculino , Publicações Periódicas como Assunto , Padrões de Prática Odontológica , Inquéritos e Questionários
Dent Traumatol ; 34(5): 329-335, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29856524


BACKGROUND/AIM: Lectin (ScLL) has been recently evaluated in the oral cavity due to its anti-inflammatory activities. ScLL could be a promising agent for blocking osteoclast activity and preventing root resorption. The aim of this study was to evaluate the effect of ScLL on the viability of the RAW 264.7 macrophage lineage, osteoclast-like maturation and the release of TNF-α and nitric oxide (NO). MATERIALS AND METHODS: The viability of RAW 264.7 cells was determined by MTT and Alamar Blue assays after ScLL treatment for 24 hours. ScLL effects on RANKL-induced osteoclast-like maturation were assessed by tartrate-resistant acid phosphatase (TRAP) staining and F-actin ring formation. The supernatant was collected to detect the release of TNF-α using ELISA and NO using a nitrite assay. RESULTS: ScLL suppressed osteoclast-like maturation by decreasing TRAP activity as well as F-actin ring formation. ScLL at 10 µg/mL showed the highest values of NO release compared with all other groups (P < .05). Lower levels of TNF-α were found for the negative control. CONCLUSIONS: ScLL at 5 µg/mL suppressed osteoclast-like maturation in vitro and had no cytotoxic effect on RAW cell cultures.

Diferenciação Celular/efeitos dos fármacos , Células Gigantes/efeitos dos fármacos , Lectinas/farmacologia , Osteoclastos/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Técnicas In Vitro , Óxido Nítrico/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
Int J Oral Maxillofac Implants ; 33(2): 335-343, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29534121


PURPOSE: The purpose of this study was to evaluate mouthguard shock absorption ability, strain, and stress generation during impact on dental implants placed in the anterior maxilla. The mouthguard material was also characterized. MATERIALS AND METHODS: Sixty experimental models were created and divided into six groups (n = 10): implant type, external hexagon (EH) and Morse taper (MT); without and with two mouthguards (MTG), EVA custom-fitted (Ct-MTG) and standard self-adapted (St-MTG). The Shore A hardness, EVA sheet and mouthguard thickness, and elastic modulus were measured to characterize the mouthguard material. A strain gauge was attached to the palatal surface of the implant abutment, which was subjected to an impact test. Distortion of the abutment and implant was determined after impact from centroid displacements in standardized radiographic images. Two-dimensional finite element models were created to represent the six groups and were submitted to nonlinear dynamic impact analysis. The data were statistically analyzed using analysis of variance (ANOVA) and Tukey test (α = .05). RESULTS: Ct-MTG resulted in higher Shore A hardness (P < .001). After the heat-forming process, the St-MTG maintained the original thickness, but the Ct-MTG thickness had decreased. The elastic modulus of EVA was 18.1 ± 0.5 MPa. The mouthguard presence reduced strain values significantly (P < .001), particularly for Ct-MTG. There was no significant difference between implant connection types EH and MT (P = .547). CONCLUSION: The external hexagon abutment resulted in higher stress and micro-displacement values. The mouthguard was able to absorb 40% to 46% of the energy caused by the impact on the dental implant.

Fenômenos Biomecânicos , Projeto do Implante Dentário-Pivô , Implantes Dentários , Análise do Estresse Dentário , Análise de Elementos Finitos , Maxila/fisiopatologia , Protetores Bucais , Dente Suporte , Projeto do Implante Dentário-Pivô/métodos , Módulo de Elasticidade , Desenho de Equipamento , Dureza , Humanos , Estresse Mecânico
Dent Traumatol ; 33(1): 57-63, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27194626


BACKGROUND/AIM: Custom-fitted mouthguards are devices used to prevent dental injuries. The aim of this study was to verify the influence of the antagonist contact on the stresses and strains of the anterior teeth, shock absorption and displacement of EVA custom-fitted mouthguards during a horizontal impact. MATERIALS AND METHODS: Finite element models of human maxillary central incisors with and without a mouthguard for different occlusion conditions (with and without antagonist contact) were created based on tomography. A nonlinear dynamic impact analysis using the single-step Houbolt method was performed in which a rigid object hit the model at 1 m s-1 . Strain and stress were evaluated by means of Von Mises and Critical modified Von Mises criterion and shock absorption during impact were calculated as well as the mouthguard displacement. RESULTS: The model without mouthguard and without antagonist contact showed the highest stress and strain values at the enamel and dentin in the tooth crown on impact compared to the model without mouthguard and with antagonist contact. Mouthguard presence reduced the stress and strain values regardless of the occlusion condition. The mouthguard displacement decreased with the mandibular antagonist contact. CONCLUSIONS: Mouthguards are efficient at decreasing the stress and strain values on the tooth in front of an impact reaching more than 90% of shock absorption. A mouthguard with balanced occlusion and maximum number of contacts with mandibular anterior teeth should be considered because it reduces mouthguard displacement.

Oclusão Dentária , Incisivo , Protetores Bucais , Traumatismos Dentários/prevenção & controle , Fenômenos Biomecânicos , Modelos Dentários , Análise do Estresse Dentário , Desenho de Equipamento , Análise de Elementos Finitos , Humanos , Incisivo/diagnóstico por imagem , Estresse Mecânico , Tomografia Computadorizada por Raios X
ROBRAC ; 25(72): 31-36, jan./mar.2016. ilus
Artigo em Português | LILACS-Express | LILACS | ID: biblio-836823


O objetivo deste trabalho é apresentar um caso clínico, demonstrando a associação entre diferentes tipos de restaurações e sistemas cerâmicos, na reabilitação do sorriso de uma paciente do gênero feminino com queixas em relação à cor e ao posicionamento dos elementos anteriores superiores. Ao exame clínico constatou-se exposição do metal da coroa metalocerâmica no elemento 21 e escurecimento, mau posicionamento dos elementos 13, 12, 22 e 23, além de diferença de cor entre os dentes. Foi proposto como plano de tratamento a substituição das coroas metalocerâmicas por novas coroas nos elementos 11 e 21, e a confecção de facetas indiretas em cerâmica reforçada por dissilicato de lítio (IPS e-max Press, Ivoclar Vivadent) nos dentes 13, 12, 22 e 23. A associação entre coroas metalocerâmicas e facetas convencionais, mostrou-se uma forma de tratamento efetiva na reabilitação do sorriso, garantindo ao final do tratamento correta seleção de cor, boa adaptação marginal das restaurações, alinhamento adequado e também, bons resultados estéticos e boa função mastigatória, contribuindo para a satisfação da paciente.

The aim of this study is to present a clinical case demonstrating the association between different types of restorations and ceramic systems in the smile rehabilitation of a female patient with complaints about the color and and placement of the maxillary anterior elements. On clinical examination it was found metal exposure of the metal-ceramic crown on element 21, darkening and poor positioning of elements 13,12, 22 and 23, as well as, color difference between the teeth. Was proposed as treatment plan the replacement of metal-ceramic crowns by new crowns in the elements 11 e 21, and the making of indirect veneers in ceramic reinforced by lithium dissilicate (IPS e-max Press, Ivoclar Vivadent) on teeth 13, 12, 22 and 23. The association between metal-ceramic crowns and conventional veneers, proved to be a form of effective treatment in the smile rehabilitation, ensuring in the end of the treatment correct color selection, good marginal adaptation of restorations, proper alignment and also good esthetic results and good chewing function , contributing to patient satisfaction.

ROBRAC ; 25(73): 80-83, abr./jun. 2016. ilus
Artigo em Português | LILACS-Express | LILACS | ID: biblio-837024


A perda óssea, em resposta à doença periodontal, compromete a estabilidade dentária, e gera desconforto ao paciente. A contenção interdentária pode ser uma opção de tratamento definitivo, destinado principalmente à população carente. Além de possuir baixo custo, é um procedimento conservador e estético que proporciona melhor distribuição de tensão ao tecido de suporte. A paciente O. P. C., 49 anos, gênero feminino, compareceu ao Hospital Odontológico da Universidade Federal de Uberlândia, apresentando sinais clínicos de periodontite, tal como mobilidade dos incisivos centrais e laterais inferiores, inflamação e sangramento a sondagem. O reestabelecimento da saúde periodontal foi obtido através da adequação do meio bucal e o protocolo para estabilização dentária e da perda óssea foi determinado. Optou-se pela técnica de contenção intracoronária com associação de fibras de reforço impregnadas por sistema adesivo e resina composta, do dente 13 ao 23. Nessa mesma sessão, também foi proposto à reconstrução estética e fechamento de diastema empregando resina composta nos dentes anteriores inferiores. Após 13 anos de acompanhamento clínico e radiográfico verificou-se paralização e estabilização da perda óssea, reestruturação da crista óssea e redução da mobilidade dentária. Sendo assim, este relato de caso de contenção interdentária com fibra de vidro e resina composta é mais uma informação segura de que este protocolo pode ser indicado em casos de perda óssea, desde que este seja seguido rotineiramente o protocolo de boa higiene bucal e acompanhamento periódico pelo cirurgião-dentista.

Bone loss in response to periodontal disease compromises the dental stability, and causes discomfort to the patient. After basic periodontal therapy, dental splinting might be a definitive option of treatment, mainly intended for the lower class population. Besides of the low cost, it is a conservative and aesthetic procedure that also improves the stress distribution in the support tissues. The patient O. P. C., 49 years, female gender, attended the Dental Hospital of the Universidade Federal de Uberlândia, presenting clinical signs of periodontitis, such as mobility in the lower incisors, inflammation and bleeding on probing. After reestablishment of periodontal health through the adequacy of the oral cavity, the protocol to stabilize the teeth and bone loss was established. We selected the splinting technique using glass fiber-reinforced associated with composite resin extending from canine to canine. In the same session, it was proposed the esthetic reconstruction and closing diastema with composite resin in the mandibular anterior teeth. After 13-years of clinical and radiographic follow-up, it was verified the stagnation and stabilization of bone loss, restructuring of the bone crest, and reduction of mobility of teeth. Thus, this case report of interdental splint with fiberglass and composite resin is more one safety information that this protocol can be indicated in cases of bone loss, since it is routinely followed by a protocol of good oral hygiene and regular monitoring by the dentist

Am J Dent ; 29(4): 234-2240, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29178754


PURPOSE: To investigate temperature rise, separating heat caused by irradiation and exotherm for three composites polymerized with three curing lights. The effect of substrate on temperature measurements was also determined. METHODS: Composite samples (n= 5) (Filtek Supreme Ultra, Filtek LS, and EsthetX HD) were placed on a thermocouple tip inside three substrates (aluminum, Delrin, and tooth). The composites were photoactivated using three curing lights (Elipar 2500 QTH, SmartLite Max LED, DemiUltra LED) at 1 mm distance. Irradiance was 798, 980, and 1,135 mW/cm2, respectively. Exotherm was determined by subtracting post-cure from the polymerization temperature curves. ANOVA and Student-Newman-Keuls post-hoc tests were used to analyze differences among peak temperatures and exotherms (significance level 0.05). RESULTS: SmartLite LED curing light resulted in higher peak temperatures and exotherms compared to the DemiUltra LED and QTH for all tested composites (16.9-20.4°C vs 12.3-14.7°C vs 8.9-9.7°C). Thus, the LEDs produced higher temperature rises than the QTH, and the LED with lower irradiance caused higher temperature rise than the LED with higher irradiance. The silorane-based Filtek LS generated significantly higher exotherm than the methacrylate-based EsthetX HD and Filtek Supreme Ultra (6.2-7.6°C vs 3.6-4.5°C vs 2.7-3.6°C). Substrate affected temperatures significantly. Temperature profiles found in Delrin substrate were comparable to tooth substrate, while aluminum substrate reduced temperatures 10-20 degrees. CLINICAL SIGNIFICANCE: Curing of restorative composites raises the temperature under a restoration due to irradiation and exothermic reaction; how much the temperature increases depends on curing light design, type of composite, and surrounding substrate. The silorane-based Filtek LS generated significantly higher exotherm than the methacrylate-based EsthetX HD and Filtek Supreme Ultra.

Resinas Compostas/química , Luzes de Cura Dentária , Temperatura Alta , Cura Luminosa de Adesivos Dentários/métodos , Técnicas In Vitro , Teste de Materiais , Polimerização
ROBRAC ; 23(68)out.-dez. 2015. tab
Artigo em Português | LILACS-Express | LILACS | ID: lil-778647


Purpose: This study evaluated the influence of cobalt-60 gamma irradiation on mechanical properties of restorative materials. Material and Methods: Two glass ionomer cement (Ketac Molar and RelyX Luting), a composite resin (Filtek Z350) and two feldspathic ceramics (VITA VMK-95 and StarLight) were evaluated. The samples were made in accordance with the ISO normative for the four-point bending test (n = 20), diametral tensile (n = 20) and microhardness tests; Knoop hardness (KHN) for glass ionomer and composite, and Vickers hardness (VHN) for ceramics (n = 10). The samples were divided into two groups: irradiated (Ir), subjectedto cobalt-60 gamma irradiation in a similar protocol used for patients with head and neck tumor; and control group (C), samples not subjected to the irradiation protocol. Results: Data were analyzed using one-way ANOVA, for diametral tensile and four-point bending test, and two-way ANOVA followed by the Tukey?s HSD test (?=.05), for Knoop and Vickers microhardness. Gamma irradiation significantly reduced the diametral tensile strength only for Ketac Molar (P<.001). Composite resin presented flexural strength values significantly decreased when submitted to the radiotherapy (P<.003). For all materials tested, the microhardness was not influenced by the region (top and bottom). Irradiation increased the KHN values for Ketac Molar (P<.000) and decreased for the RelyX Luting 2 (P<.002). The VHN was not influenced by the irradiation. Conclusions: Gamma irradiation therapy influenced the mechanical properties of the glass ionomers and the composite resin, although not alters any ceramic properties.

Objetivo: Este estudo avaliou a influência da radiação do cobalto 60 nas propriedades mecânicas de materiais restauradores. Materiais e Métodos: Dois ionômeros de vidro (Ketac Molar e RelyX Luting), uma resina composta (Filtek Z350) e duas cerâmicas feldspáticas (VITA VMK-95 e StarLight) foram avaliadas. As amostras foram confeccionadas de acordo com as normas da ISO para os testes de flexão de quatro pontos (n=20), tração diametral (n=20) e teste de microdureza; Knoop (KHN) para o ionômero de vidro e resina composta e Vickers (VHN) para a cerâmica (n=10). As amostras foram divididas em dois grupos: irradiado (Ir), submetidas à radiação gama do cobalto com um protocolo similar ao usado para o tratamento de câncer de cabeça e pescoço; e um grupo controle (C) que não recebeu radiação. Resultados: Os dados foram analisados utilizando One Way ANOVA para tração diametral e flexão de quatro pontos ukey (?=,05), para microdureza Knoop e Vickers. A resina composta apresentou e Two Way ANOVA seguido do teste de T uma diminuição nos seus valores de resistência flexural (p<0,003). Para todos os materiais testados, a microdureza não apresentou diferença estatística quanto à região (topo ou base). A irradiação aumentou os valores de microdureza do Ketac Molar (p<0,000) e diminuiu para o RelyX Luting2 (p<0,002). A VHN não foi influenciada pela irradiação. Conclusão:Irradiação gama influenciou as propriedades mecânicas dos ionômeros de vidro e resina composta, no entanto não alterou as propriedades das cerâmicas avaliadas.

Am J Dent ; 27(3): 129-33, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25208359


PURPOSE: To investigate the effect of the occlusal load condition in association with the mechanical properties of resin composite, expressed by elastic modulus and post-gel shrinkage, on stresses in a premolar restored with various composites. METHODS: Five resin composites (4 Seasons, Beautifil II, Filtek LS, Filtek Z250, and Z100) indicated for restoring posterior teeth were tested. Elastic modulus was measured using Knoop indentation tests (n=5). Post-gel shrinkage was measured with strain gauges (n = 10). Finite element analysis was used to calculate the stresses in a two-dimensional pre-molar model under four conditions: (We, without occlusal contact, representing stresses due to composite shrinkage only; Ct: contact generated between enamel of restored tooth and antagonist tooth; Cm: contact on tooth/composite restoration margin; Cc: stable centric contact on the composite restoration). RESULTS: Elastic modulus varied between 12.6 (Filtek LS) and 21.5 (Z100) GPa; post-gel shrinkage varied between 0.11 (Filtek LS) and 0.96 (Z100) vol%. Composites with higher elastic modulus and post-gel shrinkage increased stress in the restored tooth. Occlusal contact on the tooth/composite restoration margin increased the stresses around the margin of the restoration. Stable centric contact on the restoration resulted in better stress distribution.

Força de Mordida , Resinas Compostas/química , Materiais Dentários/química , Restauração Dentária Permanente , Dente Pré-Molar/fisiopatologia , Bis-Fenol A-Glicidil Metacrilato/química , Esmalte Dentário/fisiopatologia , Módulo de Elasticidade , Análise de Elementos Finitos , Dureza , Humanos , Teste de Materiais , Fenômenos Mecânicos , Polimerização , Dióxido de Silício/química , Estresse Mecânico , Propriedades de Superfície , Zircônio/química
ROBRAC ; 23(65)jul 2014. ilus
Artigo em Português | LILACS-Express | LILACS | ID: lil-763974


Dental structure deterioration, like enamel erosion, is caused through dissolution by endogenous or exogenous acid substances in the oral cavities. The demineralization caused exclusively by endogenous acid as the chronic regurgitations and gastric dysfunctions that cause erosive tooth lesions are known as perimolysis. This clinical case report describes the oral rehabilitation of a patient with perymolisis using direct composite resin restorations. This patient had erosive lesions on lingual, incisor, and occlusal surfaces of almost all teeth, a situation which, among other disturbances, caused alteration in vertical dimension of occlusion, muscular pain, and esthetic damage. Multifactorial aspects were applied to diagnosis, planning, and functional and esthetic rehabilitation of anteriorand posterior teeth.

A deterioração estrutural dental, como a erosão do esmalte, é causadapor dissoluções de substâncias ácidas endógenas ou exógenas nas cavidades orais. A desmineralização causada exclusivamente por ácido endógeno como as regurgitações crônicas e disfunções gástricas que causam lesões dentárias erosivas são conhecidos como perimólise. Este relato de caso clínico descreve a reabilitação oral de um paciente com perimólise usando restaurações de resina composta direta. Este paciente apresentava lesões erosivas na língua, incisivos e superfícies oclusais de quase todos os dentes, uma situação que, entre outros distúrbios, causa alteração na dimensão vertical de oclusão, dor muscular e dano estético. Aspectos multifatoriais foram aplicados ao diagnóstico, planejamento e reabilitação funcional e estética dos dentes anteriores e posteriores.

J Oral Sci ; 56(2): 105-12, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24930746


The purpose of this study was to investigate the influence of gutta-percha solvents on the bond strength of fiberglass post to root canal dentin. Forty bovine incisors were decoronated, prepared, filled, and randomly distributed into four groups (n = 10) according to the gutta-percha solvent used: control, xylene, eucalyptol and orange oil. After root canal treatment, the posts were cemented into the prepared root canals using a resin-based cement. A micro push-out test was executed, and the patterns of failure were assessed with microscopy. The data were analyzed using two-way ANOVA followed by Tukey's test. The control group exhibited greater bond strength compared to the eucalyptol group in the cervical and middle thirds of the root (P < 0.05); however, it did not differ significantly from the xylene and orange oil groups (P > 0.05). No difference was observed in the values of the xylene, orange oil, and eucalyptol groups (P > 0.05). The cervical third had higher values than the apical third for all tested solvents (P < 0.05). Adhesive failure between resin cement and dentin was the most frequent type of failure. The use of xylene and orange oil as gutta-percha solvents did not influence the bond strength of fiberglass posts to root canal dentin.

Cavidade Pulpar , Dentina , Vidro , Guta-Percha , Técnica para Retentor Intrarradicular , Solventes , Animais , Bovinos
ROBRAC ; 23(64)jan.-mar. 2014. ilus
Artigo em Inglês | LILACS-Express | LILACS | ID: lil-747212


The aim of this article is to describe a step-by-step protocol for emergency care of a young patient with multidisciplinary direct restorative approach for recovering crown-root fractures. Fractures of maxillary incisors are a frequent consequence of trauma in children and teenagers. Glass fiber post associated with composite resin restoration represents a conservative approach for this rehabilitation. This paper presents a case of a 14-year-old male patient with a crown-root fracture in a left maxillary lateral incisor. The patient was submitted to a periodontal surgery for coronal lengthening. After that, the post luting and restoration technique was performed. Finally, a mouthguard was made for preventing new trauma. The multidisciplinary treatment described for crown-root fracture rehabilitation is simple, providing esthetics and function with a conservative approach in younger patients.

O objetivo deste artigo é descrever passo a passo, um protocolo para tratamento de emergência de pacientes jovens, com abordagem multidisciplinar e restauração direta em resina composta para a reabilitação de fraturas corono-radiculares. Fraturas de incisivos superiores são uma consequência frequente de traumas em crianças e adolescentes. Pinos de fibra de vidro associados às restaurações em resina composta representam abordagem conservadora para este tipo de situação. Este artigo apresenta caso clinico de um paciente do sexo masculino de 14 anos de idade, com fratura corono- radicular em incisivo lateral superior esquerdo. Inicialmente,o paciente foi submetido à cirurgia periodontal para aumento de coroa clínica. Depois, foi realizada cimentação do pino de fibra de vidro, seguido de restauração direta em resina composta. Por fim, um protetor bucal foi confeccionado para prevenir novo trauma. O tratamento multidisciplinar descrito para reabilitação de fraturas corono-radiculares é simples, proporcionando estética e função com uma abordagem conservadora em pacientes jovens.

ROBRAC ; 21(57)out. 2012. ilus
Artigo em Português | LILACS-Express | LILACS | ID: lil-657318


Grande variedade de tratamento é indicada para dentes traumatizados, com fratura de esmalte e dentina, durante a infância e adolescência, dependente da quantidade de remanescente dentário. Dentre as possibilidades de tratamento para recuperação estética, funcional e biomecânica, materiais odontológicos que mimetizam propriedades das estruturas dentárias são almejados. Pinos de fibra de vidro tem sido cada vez mais utilizados pela capacidade de distribuir as tensões de forma favorável, minimizando o risco de fraturas em dentes com mínimo remanescente coronário, podendo ser associados à restaurações diretas e indiretas. O objetivo do presente relato de caso clínico é apresentar alternativa de tratamento com maior preservação de remanescente assegurando retenção do material restaurador, selamento do canal radicular e adequada longevidade de tratamento para dentes com fratura coronária com envolvimento de esmalte e dentina, em paciente hebiátrico.

Wide range of treatment is indicated for traumatized teeth with enamel and dentin fracture during childhood and adolescence, dependent on the amount of remaining. Among the treatment options for recovery aesthetic and functional biomechanics, dental materials that mimic properties of dental structures are desired. Glass fiber posts have been increasingly used for its ability to distribute stresses favorably, minimizing the risk of fractures in teeth with minimal remaining coronal, and may be associated with direct and indirect restorations. The purpose of this case report is to present an alternative treatment with greater preservation of remnant ensuring retention of the restorative material, sealing the root canal and adequate treatment for longevity of teeth with coronal fracture involving enamel and dentin of a hebiatric patient.