RESUMO
Introduction: Cervical suction lipectomy (CSL) procedures result in practically inevitable complications after the operation, such as facial edema and bruise. Photobiomodulation therapy (PBMT) can be used for analgesia, modulation of inflammatory processes, and improved tissue healing. Case Report: We have reported two cases of patients in which this therapy was used to manage complications-related CSL. As they had already been medicated and still had these side effects, the PBMT was proposed for local analgesia, nerve repair, and modulation of the inflammatory process. Within 72 hours after a single PBMT session, there was an important reduction in the severity of all situations. Conclusion: PBMT seems safe and effective in managing pain and edema-related CSL.
RESUMO
OBJECTIVE: In this study a dentistry nanocomposite with prolonged antibacterial activity using silica nanoparticles (SNPs) loaded with chlorhexidine (CHX) was developed. METHODS: SNPs were coated with the Layer-by-Layer technique. Dental composites were prepared with organic matrix of BisGMA/TEGDMA and SNPs with or without CHX (0, 10, 20 or 30% w/w). The physicochemical properties of the developed material were evaluated and agar diffusion method was used to test the antibacterial. In addition, the biofilm inhibitory activity of the composites was evaluated against S. mutans. RESULTS: SNPs were rounded with diameters about 50 nm, the organic load increased with increasing deposited layers. Material samples with SNPs loaded with CHX (CHX-SNPs) showed the highest values of post-gel volumetric shrinkage, that ranged from 0.3% to 0.81%. Samples containing CHX-SNPs 30% w/w showed the highest values of flexural strength and modulus of elasticity. Only samples containing SNPs-CHX showed growth inhibition against S. mutans, S. mitis and S. gordonii in a concentration-dependent manner. The composites with CHX-SNPs reduced the biofilm formation of S. mutans biofilm at 24 h and 72 h. SIGNIFICANCE: The nanoparticle studied acted as fillers and did not interfere with the evaluated physicochemical properties while providing antimicrobial activity against streptococci. Therefore, this initial study is a step forward to the synthesis of experimental composites with improved performance using CHX-SNPs.
Assuntos
Clorexidina , Nanopartículas , Clorexidina/farmacologia , Clorexidina/química , Dióxido de Silício/farmacologia , Dióxido de Silício/química , Antibacterianos/farmacologia , Antibacterianos/química , Nanopartículas/química , Streptococcus mutansRESUMO
Chitosan particles loaded with dibasic calcium phosphate anhydrous (DCPA) is a promising strategy for combining antimicrobial and osteoconduction properties in regenerative medicine. However, mostly micrometer-sized particles have been reported in the literature, limiting their use and reducing their effect in the biomedical field. We have recently overcome this limitation by developing submicrometer-sized particles with electrospray technique. The objective of this study was to understand how the process parameters control the size and properties of submicrometer chitosan particles loaded with DCPA. Solutions of 10 mg/mL chitosan and 2.5 mg/mL DCPA in a 90% acetic acid were electrosprayed under three distinct flow rate conditions: 0.2, 0.5, and 1.0 mL/h. The particles were crosslinked in a glutaraldehyde atmosphere and characterized in terms of their morphology, inorganic content, zeta potential, and minimum inhibitory concentration (MIC) against S. mutans. All conditions showed particles with two similar morphologies: one small-sized with a spherical shape and another larger-sized with a bi-concave shape. All generated a broad particle size distribution, with a similar mean size of ~ 235 nm. The addition of DCPA decreased the zeta potential for all the samples, but it was above 30 mV, indicating a low aggregation potential. The lower flow rate showed the worst efficacy for DCPA incorporation. Antimicrobial activity was greater in chitosan/DCPA particles with flow rate of 0.5 mL/h. It can be concluded that the flow rate of 0.5 mL/h presents the best compromise solution in terms of morphology, zeta potential, MIC, and inorganic content.
Assuntos
Anti-Infecciosos , Quitosana , Tamanho da Partícula , Fosfatos de Cálcio , Anti-Infecciosos/farmacologiaRESUMO
INTRODUÇÃO: Os aparelhos intraorais (AIO) possuem indicação para tratamento da Síndrome da Apneia Obstrutiva do Sono (SAOS) inclusive em pacientes com baixa adesão ao CPAP. A polissonografia com o AIO pode confirmar benefício terapêutico. MÉTODOS: Compararam-se os resultados polissonográficos de um AIO semiflexível em pacientes sob uso inadequado do CPAP por meio de estudo-piloto retrospectivo, incluindo 17 pacientes (11 homens e 6 mulheres) com 53,7 +- 7,8 anos, IMC de 27,5 +- 4,1kg/m2 e índice de apneia- -hipopneia basal (IAH) de 35,0 +- 19,8/h. Confirmados o uso inadequado ou recusa do CPAP, os pacientes receberam um aparelho com propulsão semiflexível (A-QUALITY) e, após titulação completa, novas polissonografias foram comparadas aos registros basais e com CPAP. Utilizou-se ANOVA para medidas repetidas e post-hoc Bonferroni (p < 0,05). RESULTADOS: Houve redução semelhante no IAH com AIO (7,7 +- 1,7/h) e CPAP (6,1 +- 1,6/h), ambos comparados ao basal (p < 0,001). O índice de dessaturação de O2 foi reduzido com AIO (2,4 +- 0,6/h) e CPAP (1,3 +- 0,6/h), ambos comparados ao basal (15,7 +- 3,8), (p <0,001). O índice de despertares também foi minimizado com AIO (7,2 +- 1,9/h) e CPAP (4,2 +- 0,7/h), ambos comparados ao basal (18,9 +- 5,3), (p<0,001). A eficiência do sono foi maior com o AIO comparado ao CPAP (87,2 +- 2,1 x 75,6 +- 3,9) (p<0,05). CONCLUSÃO: O tratamento com o aparelho selecionado resultou em melhora nos registros polissonográficos nessa amostra e pode ser indicado como alternativa ao CPAP em pacientes subtratados (AU)
INTRODUCTION: Intraoral appliances (IOA) are indicated for treatment of Obstructive Sleep Apnea Syndrome (OSAS) even in patients with poor adherence to CPAP. Polysomnography with IOA may confirm therapeutic benefit. METHODS: Polysomnographic results of a semiflexible IOA in patients under inadequate use of CPAP were compared by a retrospective pilot study including 17 patients (11 men and 6 women) aged 53.7 +- 7.8 years, BMI of 27.05 +- 4.1kg/m2 and basal apnea-hypopnea index (AHI) of 35.0 +- 19.8/h. Confirmed the inappropriate use or refusal of CPAP, the patients received a semiflexible propulsion device (AQUALITY) and, after complete titration, new polysomnographies were compared to baseline and CPAP registers. ANOVA was used for repeated and post-hoc Bonferroni measurements (p <0.05). RESULTS: There was a similar reduction in AHI with OA (7.7 +- 1.7/h) and CPAP (6.1 +- 1.6/h), both compared to baseline (p <0.001). The O2 desaturation index was reduced with IOA (2.4 +- 0.6 h) and CPAP (1.3 +- 0.6/h), both compared to baseline (15.7 +- 3.8) (p <0.001). Awakening rates were also minimized with IOA (7.2 +- 1.9/h) and CPAP (4.2 +- 0.7/h), both compared to baseline (18.9 +- 5.3) (p <0.001). Sleep efficiency was higher with IOA compared to CPAP (87,2 +- 2,1 x 75,6 +- 3,9) (p <0.05). CONCLUSION: Treatment with the selected device resulted in improved polysomnographic records in this sample and may be indicated as an alternative to CPAP in undertreated patients. (AU)
Assuntos
Humanos , Desenho de Aparelho Ortodôntico , Polissonografia , Avanço Mandibular , Apneia Obstrutiva do Sono , Pressão Positiva Contínua nas Vias AéreasRESUMO
O ameloblastoma é um tumor odontogênico benigno, localmente invasivo, capaz de infiltrar-se pelos espaços medulares do osso e, quando em estágio inicial, geralmente não apresenta indícios radiográficos ou macroscópicos. Muitas vezes, pacientes submetidos a tratamento ressectivo perdem grande parte da maxila ou mandíbula, necessitando de uma alternativa de tratamento para restabelecer a função e a estética. O objetivo deste relato de caso foi apresentar um acompanhamento de quatro anos de uma reabilitação com implantes zigomáticos em paciente submetido à ressecção de maxila anterior devido a um tumor odontogênico do tipo ameloblastoma. Quatro meses após a realização da cirurgia de ressecção do ameloblastoma na região anterior de maxila, foram instalados dois implantes com ancoragem zigomática no lado esquerdo, um implante com ancoragem zigomática no lado direito e dois implantes regulares hexágono externo no lado direito. Em seguida, foi feita uma prótese provisória imediata. Seis meses depois, os implantes foram carregados com a prótese final em resina acrílica. Após quatro anos de acompanhamento, não foram observados sintomas dolorosos, inflamação ou infecção peri-implantar, instabilidade do implante ou reabsorção óssea. No presente caso, a reabilitação da maxila atrófica com implantes no osso zigomático proporcionou bons resultados funcionais e estéticos a longo prazo. Assim, o uso de implantes zigomáticos associados a implantes padrão oferece vantagens na reabilitação de maxilares severamente reabsorvidos, principalmente quando a indicação é feita corretamente e com o conhecimento da técnica cirúrgica. (AU)
Ameloblastoma is a benign, locally invasive odontogenic tumor capable of infiltrating the bone marrow spaces, and when at the initial stage, it generally does not show radiographic or macroscopic evidence. Patients undergoing resection treatment lose a large part of the maxilla or mandible, requiring an alternative treatment to re-establish the function and aesthetics. The objective of this case report was to present a 4-years follow-up of a rehabilitation with zygomatic implants in a patient submitted to anterior maxillary resection due to an odontogenic tumor of the ameloblastoma type. After 4 months of the ameloblastoma resection surgery in the anterior maxillary region, 2 implants were placed with zygomatic anchoring on the left side, 1 implant with zygomatic anchoring on the right side and 2 regular external hexagon implants placed on the right side and then it was done an immediate provisional prosthesis. Six months later, the implants were loaded with the fi nal acrylic resin prosthesis. After 4-years of follow-up no painful symptoms, inflammation or peri-implant infection, implant instability or bone resorption were observed. In the present case, the atrophic maxilla rehabilitation with implants in the zygomatic bone provided long-term functional and aesthetic results. Thus, the zygomatic implants associated with standard implants offers advantages in severely reabsorbed maxillae rehabilitation, especially when the indication is made correctly and also with the knowledge of the surgical technique. (AU)
Assuntos
Humanos , Feminino , Pessoa de Meia-Idade , Ameloblastoma , Tumores Odontogênicos , Implantes Dentários , Implantação Dentária Endóssea , Estética DentáriaRESUMO
INTRODUCTION: The surgically assisted rapid maxillary expansion is a procedure that reduces the resistance of the sutures correcting the posterior crossbite in adults. OBJECTIVE: The aim of this study was to evaluate the periodontal status of 17 adults submitted to this procedure. METHODS: The clinical attachment level (CAL), gingival recession, attached gingiva and bleeding were evaluated in maxillary first premolars and molars, central and lateral incisors of right and left sides before surgery, 5 days and 6 months after. Means, standard deviation, medians, minimum and maximum values were compared among the evaluations using the Friedman and McNemar tests. RESULTS: There was a statistically significant increase in CAL in the right central incisor, right and left premolars and right and left molars. There was a statistically significant increase in gingival recession in the right and left premolars and molars. The amount of attached gingiva significantly decreased in right premolars and right and left molars. There was increase in bleeding in most of the teeth. CONCLUSION: Results indicated that the surgically assisted rapid maxillary expansion might cause alterations in periodontal tissue.
Assuntos
Retração Gengival/etiologia , Maxila/cirurgia , Técnica de Expansão Palatina/efeitos adversos , Perda da Inserção Periodontal/etiologia , Adulto , Feminino , Hemorragia/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Técnica de Expansão Palatina/instrumentaçãoRESUMO
OBJECTIVE: to verify the effect of the addition of dicalcium phosphate dihydrate (DCPD) particles functionalized with di- or triethylene glycol dimethacrylate (DEGDMA or TEGDMA) on the degree of conversion (DC), post-gel shrinkage (PS), mechanical properties, and ion release of experimental composites. METHODS: Four composites were prepared containing a BisGMA/TEGDMA matrix and 60â¯vol% of fillers. The positive control contained only barium glass fillers, while in the other composites 15â¯vol% of the barium was replaced by DCPD. Besides the functionalized particles, non-functionalized DCPD was also tested. DC after 24â¯h (nâ¯=â¯3) was determined by FTIR spectroscopy. The strain gage method was used to obtain PS 5â¯min after photoactivation (nâ¯=â¯5). Flexural strength and modulus (nâ¯=â¯10) were calculated based on the biaxial flexural test results, after specimen storage for 24â¯h or 60 days in water. The same storage times were used for fracture toughness testing (FT, nâ¯=â¯10). Calcium and phosphate release up to 60 days was quantified by ICP-OES (nâ¯=â¯3). Data were analyzed by ANOVA/Tukey test (alpha: 5%). RESULTS: Composites containing functionalized DCPD presented higher DC than the control (pâ¯<â¯0.001). The material containing DEGDMA-functionalized particles showed higher PS than the other composites (pâ¯<â¯0.001). After 60 days, only the composite with DEGDMA-functionalized DCPD presented fracture strength similar to the control, while for flexural modulus only the composite with TEGDMA-functionalized particles was lower than the control (pâ¯<â¯0.001). FT of all composites containing DCPD was higher than the control after 60 days (pâ¯<â¯0.005). Calcium release was higher for the composite with non-functionalized DCPD at 15 days and no significant reductions were observed for composites with functionalized DCPD during the observation period (pâ¯<â¯0.001). For all the tested composites, phosphate release was higher at 15 days than in the subsequent periods, and no difference among them was recorded at 45 and 60 days (pâ¯<â¯0.001). CONCLUSIONS: DCPD functionalization affected all the studied variables. The composite with DEGDMA-functionalized particles was the only material with strength similar to the control after 60 days in water; however, it also presented the highest shrinkage. The presence of DCPD improved FT, regardless of functionalization. DCPD functionalization reduced ion release only during the first 15 days.
Assuntos
Fosfatos de Cálcio/química , Fenômenos Mecânicos , Resinas Sintéticas/química , Estresse MecânicoRESUMO
This study evaluated the influence of formulation and thermal treatment on the degree of conversion, fracture toughness, flexural strength, and elastic modulus of experimental composites. Six composites were analyzed at BisGMA : TEGDMA molar ratios of 1 : 1 and 7 : 3 with filler at 30, 50, and 70 wt%. The degree of conversion was analyzed by Fourier transform infrared spectroscopy, fracture toughness was measured using the single-edge notched beam, and flexural strength and elastic modulus were measured with the 3-point bend test. For all tests, one-half of the specimens received thermal treatment at 170°C for 10 min. Data were analyzed by the Kruskal-Wallis or ANOVA/Tukey's test (α = 5%). The 1 : 1 BisGMA : TEGDMA ratio showed higher properties than the 7 : 3 ratio. Although the material with 70% filler had a conversion lower than the one with 50%, it showed higher mechanical properties. The thermal treatment improved all properties in all materials. Therefore, the use of an equimolar ratio of BisGMA : TEGDMA can be paired with 70 wt% filler to design dental composites that possess increased advantageous physical and chemical properties. Furthermore, the simple and low-cost method of thermal treatment proposed for use in clinical dentistry has been shown to effectively improve the properties of all evaluated materials.
Assuntos
Bis-Fenol A-Glicidil Metacrilato/química , Resinas Compostas/química , Estresse Mecânico , Bis-Fenol A-Glicidil Metacrilato/uso terapêutico , Resinas Compostas/uso terapêutico , Análise do Estresse Dentário , Humanos , Teste de Materiais , Polietilenoglicóis/química , Polietilenoglicóis/uso terapêutico , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/uso terapêutico , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Resistência à TraçãoRESUMO
Bulk-fill composites are claimed to be restorative materials used in deep preparations and effectively photoactivated in layers up to 4 mm. The aim of the present study was to evaluate the degree of conversion, post-gel volumetric shrinkage, and cytotoxicity of six bulk-fill and two conventional composites. Degree of conversion was determined by FTIR spectroscopy; post-gel volumetric shrinkage was determined using the strain gauge method; and cytotoxicity in human fibroblasts was evaluated indirectly by the MTT assay. Data were subjected to one-way ANOVA/Tukey's test (α = 0.05). All materials, including bulk-fill and conventional composites, were classified as non-toxic, with cell viability higher than 70%. Bulk-fill composites exhibited volumetric shrinkage similar to or lower (1.4 to 0.4%) than that of conventional composites (1.7-2.1%). However, only four of the bulk-fill composites were able to sustain a homogeneous conversion at the 4-mm depth. Despite their non-toxicity and shrinkage similar to that of conventional materials, not all commercial bulk-fill materials were able to maintain a conversion as high as 80% of the superficial layer, at the 4-mm depth, indicating some failure in the bulk-fill design of some commercial brands. Therefore, the use of bulk-fill materials in dental practice is advantageous, but special attention should be given to the selection and correct use of the materials.
Assuntos
Resinas Compostas/química , Resinas Compostas/toxicidade , Polimerização , Análise de Variância , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Humanos , Teste de Materiais , Transição de Fase , Processos Fotoquímicos , Valores de Referência , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Fatores de TempoRESUMO
ABSTRACT Introduction: The surgically assisted rapid maxillary expansion is a procedure that reduces the resistance of the sutures correcting the posterior crossbite in adults. Objective: The aim of this study was to evaluate the periodontal status of 17 adults submitted to this procedure. Methods: The clinical attachment level (CAL), gingival recession, attached gingiva and bleeding were evaluated in maxillary first premolars and molars, central and lateral incisors of right and left sides before surgery, 5 days and 6 months after. Means, standard deviation, medians, minimum and maximum values were compared among the evaluations using the Friedman and McNemar tests. Results: There was a statistically significant increase in CAL in the right central incisor, right and left premolars and right and left molars. There was a statistically significant increase in gingival recession in the right and left premolars and molars. The amount of attached gingiva significantly decreased in right premolars and right and left molars. There was increase in bleeding in most of the teeth. Conclusion: Results indicated that the surgically assisted rapid maxillary expansion might cause alterations in periodontal tissue.
RESUMO Introdução: a expansão rápida da maxila assistida cirurgicamente (ERMAC) é um procedimento que reduz a resistência das suturas, corrigindo a mordida cruzada posterior em adultos. Objetivo: o objetivo deste estudo foi avaliar o status periodontal de 17 adultos submetidos a esse procedimento. Métodos: o nível clínico de inserção (NCI), a recessão gengival, gengiva inserida e sangramento foram avaliados nos primeiros pré-molares, molares, incisivos centrais e laterais superiores dos lados direito e esquerdo antes da cirurgia, e depois de 5 dias e 6 meses. Médias, desvios-padrão, medianas, valores mínimos e máximos foram comparados entre as avaliações, usando os testes de Friedman e McNemar. Resultados: houve aumento estatisticamente significativo no NCI no incisivo central direito, pré-molares direito e esquerdo e molares direito e esquerdo. Houve aumento estatisticamente significativo na recessão gengival nos pré-molares e nos molares direito e esquerdo. A quantidade de gengiva inserida diminuiu significativamente nos pré-molares direitos e molares direitos e esquerdos. Houve aumento no sangramento na maioria dos dentes. Conclusão: os resultados indicaram que a ERMAC pode causar alterações no tecido periodontal.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Técnica de Expansão Palatina/efeitos adversos , Perda da Inserção Periodontal/etiologia , Retração Gengival/etiologia , Maxila/cirurgia , Técnica de Expansão Palatina/instrumentação , Hemorragia/etiologiaRESUMO
Abstract: Bulk-fill composites are claimed to be restorative materials used in deep preparations and effectively photoactivated in layers up to 4 mm. The aim of the present study was to evaluate the degree of conversion, post-gel volumetric shrinkage, and cytotoxicity of six bulk-fill and two conventional composites. Degree of conversion was determined by FTIR spectroscopy; post-gel volumetric shrinkage was determined using the strain gauge method; and cytotoxicity in human fibroblasts was evaluated indirectly by the MTT assay. Data were subjected to one-way ANOVA/Tukey's test (α = 0.05). All materials, including bulk-fill and conventional composites, were classified as non-toxic, with cell viability higher than 70%. Bulk-fill composites exhibited volumetric shrinkage similar to or lower (1.4 to 0.4%) than that of conventional composites (1.7-2.1%). However, only four of the bulk-fill composites were able to sustain a homogeneous conversion at the 4-mm depth. Despite their non-toxicity and shrinkage similar to that of conventional materials, not all commercial bulk-fill materials were able to maintain a conversion as high as 80% of the superficial layer, at the 4-mm depth, indicating some failure in the bulk-fill design of some commercial brands. Therefore, the use of bulk-fill materials in dental practice is advantageous, but special attention should be given to the selection and correct use of the materials.
Assuntos
Humanos , Resinas Compostas/toxicidade , Resinas Compostas/química , Polimerização , Valores de Referência , Propriedades de Superfície , Fatores de Tempo , Teste de Materiais , Sobrevivência Celular/efeitos dos fármacos , Reprodutibilidade dos Testes , Análise de Variância , Espectroscopia de Infravermelho com Transformada de Fourier , Transição de Fase , Processos Fotoquímicos , Fibroblastos/efeitos dos fármacosRESUMO
OBJECTIVES: This study aims to correlate patient-reported reactions with in vitro analyses of the pH, abrasive quality, and cytotoxicity of four toothpastes. MATERIALS AND METHODS: One hundred twenty-one patients received non-identified samples of toothpaste to be used for 6 days and answered a questionnaire about their sensations. In vitro analysis: the pH of toothpastes was measured with a pH meter. The abrasivity of toothpastes was evaluated against composite resin specimens (n = 10). A toothbrushing machine was used to simulate wear, which was indirectly measured by mass loss using a scale. Cell culture media conditioned with toothpaste were used to assess the cytotoxicity. Confluent cells were kept in contact with the conditioned media or control for 24 h. The cell viability was measured using the 3-(bromide, 4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium (MTT)-reduction assay. The obtained data on the pH, weight loss, and cell viability were compared by ANOVA/Tukey's tests (p < 0.05). RESULTS: With the exception of the bleaching effect paste, the Oral B® paste produced the highest frequencies of irritation reports, tooth sensitivity, taste discomfort, and texture discomfort in the clinical study; patients also reported rougher teeth, soft tissue peeling, dry mouth, thrush, tingling, and taste changes in response to this paste. The in vitro analysis demonstrated that Oral B® had the lowest pH, the highest abrasivity, and produced the lowest cell viability (p < 0.01). CONCLUSION: Results suggest that low pH toothpastes that are highly abrasive and cytotoxic may cause undesirable reactions in patients. CLINICAL RELEVANCE: Toothpaste's properties should be well known for indication to patient therefore minimizing discomfort reports.
Assuntos
Abrasão Dentária/etiologia , Cremes Dentais/efeitos adversos , Adulto , Sobrevivência Celular , Células Cultivadas , Resinas Compostas , Estudos Cross-Over , Feminino , Fibroblastos/efeitos dos fármacos , Gengiva/citologia , Humanos , Concentração de Íons de Hidrogênio , Masculino , Teste de Materiais , Pessoa de Meia-Idade , Inquéritos e Questionários , Cremes Dentais/químicaRESUMO
Nowadays, the main reasons for replacement of resin-based composite restorations are fracture or problems with the integrity of their interface, such as marginal staining, microleakage, or secondary caries. The aim of the present study was to evaluate the influence of the organic matrix on polymerization stress (PS), degree of conversion (DC), elastic modulus (E), flexural strength (FS), Knoop hardness (KHN), sorption (SP), and solubility (SL). In order to obtain a material which combines better mechanical properties with lower PS, seven experimental composites were prepared using BisGMA to TEGDMA molar ratios of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 and 8:2 and 40% of silica. PS was obtained in a universal testing machine, using acrylic as bonding substrate. DC was determined using Fourier Transform Raman spectroscopy. E and FS were obtained by the three-point bending test. KHN was measured by a microindentation test using a load of 25 g for 30 s. SP and SL were assessed according to ISO 4049. The data were submitted to one-way ANOVA. The increase in BisGMA concentration resulted in the decrease of PS, DC, E, FS and KHN. However, it did not change the SP and SL values. FS, E and KHN showed a strong and direct relationship with the DC of the materials. The composite material with a BisGMA to TEGDMA molar ratio of 1:1 was the one with better mechanical properties and lower PS.
Assuntos
Resinas Compostas/química , Análise do Estresse Dentário , Metacrilatos/química , Polietilenoglicóis/química , Polimerização/efeitos dos fármacos , Ácidos Polimetacrílicos/química , Adsorção , Análise de Variância , Módulo de Elasticidade , Testes de Dureza , Teste de Materiais , Transição de Fase/efeitos dos fármacos , Fotoiniciadores Dentários/química , Maleabilidade , Valores de Referência , Reprodutibilidade dos Testes , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de TempoRESUMO
Nowadays, the main reasons for replacement of resin-based composite restorations are fracture or problems with the integrity of their interface, such as marginal staining, microleakage, or secondary caries. The aim of the present study was to evaluate the influence of the organic matrix on polymerization stress (PS), degree of conversion (DC), elastic modulus (E), flexural strength (FS), Knoop hardness (KHN), sorption (SP), and solubility (SL). In order to obtain a material which combines better mechanical properties with lower PS, seven experimental composites were prepared using BisGMA to TEGDMA molar ratios of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 and 8:2 and 40% of silica. PS was obtained in a universal testing machine, using acrylic as bonding substrate. DC was determined using Fourier Transform Raman spectroscopy. E and FS were obtained by the three-point bending test. KHN was measured by a microindentation test using a load of 25 g for 30 s. SP and SL were assessed according to ISO 4049. The data were submitted to one-way ANOVA. The increase in BisGMA concentration resulted in the decrease of PS, DC, E, FS and KHN. However, it did not change the SP and SL values. FS, E and KHN showed a strong and direct relationship with the DC of the materials. The composite material with a BisGMA to TEGDMA molar ratio of 1:1 was the one with better mechanical properties and lower PS.
Assuntos
Resinas Compostas/química , Análise do Estresse Dentário , Metacrilatos/química , Polietilenoglicóis/química , Polimerização/efeitos dos fármacos , Ácidos Polimetacrílicos/química , Adsorção , Análise de Variância , Módulo de Elasticidade , Testes de Dureza , Teste de Materiais , Transição de Fase/efeitos dos fármacos , Fotoiniciadores Dentários/química , Maleabilidade , Valores de Referência , Reprodutibilidade dos Testes , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de TempoRESUMO
O uso de implantes para a reabilitação oral é pratica comum na odontologia. Entretanto, falhas são relatadas na literatura. Para evitar o insucesso, cuidados na preparação do leito receptor dos implantes são importantes e, entre esses cuidados, o não aquecimento do osso adjacente é fundamental. A elevação da temperatura durante a osteotomia é um fator importante para o fracasso da técnica cirúrgica. O objetivo do trabalho foi revisar a literatura sobre a influência da irrigação na osseointegração. Foram realizadas buscas em bases de dados no portal de periódicos da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), National Center for Biotechnology Information (NCBI)/U.S., National Library of Medicine (PubMed) e Google Acadêmico, no perído de 1964 a 2012. Foram selecionados 333 estudos relacionados à busca, sendo que 203 foram descartados por não abordarem de forma clara a relação entre o controle do calor gerado e o procedimento de instalação de implantes orais. Os 130 artigos remanescentes foram selecionados e 50 estudos foram incluídos. Foram identificados os fatores relacionados aos diferentes sistemas de irrigação do tipo externo e do tipo interno usados para o controle da temperatura, tanto das brocas como do tecido ósseo adjacente, durante a osteotomia para a inserção de implantes. Baseado na literatura, é imprescindível a utilização da irrigação durante a confecção dos alvéolos cirúrgicos para a inserção de implantes dentários, independentemente de serem interno ou externo, já que os estudos mostram que o desempenho de ambos é semelhante, salvo em casos específicos, como no caso de cirurgias guiadas, em que a irrigação interna parece ser mais eficiente.
The use of implants for oral rehabilitation is a common practice in dentistry, though failures are reported in literature. To avoid failure, careful preparation of the recipient site of the implants is important, and among these cares, not heating the adjacent bone is essential. Increasing temperature during osteotomy is an important factor in failure of the surgical technique. This study aimed to review the literature about the influence of irrigation on osseointegration. Searches were conducted in databases on the portal of periodicals from Coordination of Improvement of Higher Education Personnel (CAPES), National Center for Biotechnology Information (NCBI) / U.S., National Library of Medicine (PubMed) and Google Scholar, in the period from 1964 to 2012. Then, 333 studies were selected, but 203 were discarded for not clearly addressing the subject. One hundred and thirty remaining articles were selected, and 50 studies were included. The study identified the factors related to the external and internal irrigation systems used to control the temperature of drills and adjacent bone tissue during the osteotomy for the insertion of implants. Based on the literature the irrigation during the surgical preparation for the insertion of dental implants is fundamental, independently from being internal or external systems, once the performance of both is similar, except in specific cases, including guided surgery in which the internal irrigation appears to be more efficient.
RESUMO
OBJECTIVE: To verify the null hypothesis that in a high compliance testing system stress magnitude was not influenced by specimen dimensions and, therefore, by its cavity configuration factor (C-factor) and volume. METHODS: Twelve experimental groups were defined according to the specimen height (0.5, 1, 2 or 4mm) and diameter (4, 6 or 8mm). A selfcure composite (Bisfil 2B, Bisco) was inserted between the flat surfaces of two acrylic rods attached to the opposite ends of a universal testing machine. An extensometer with a gauge length of 10mm was attached to both rods to monitor specimen height. Force development was monitored for 30min and nominal stress was calculated dividing the maximum force value by the crossection of the rod. A second set of data was obtained dividing nominal stress by the corresponding longitudinal compliance (LC) of the system for that particular specimen size. Data was analyzed using two-way ANOVA/Tukey test (nominal stress), Kruskal/Wallis (normalized stress), both at alpha=5%, and regression analysis having either C-factor or volume as independent variable. RESULTS: Regression analysis involving nominal stress did not reveal strong relationships with the independent variables (C-factor: 0.437, volume: 0.662). A strong relationship was found between normalized stress and specimen volume (Radj(2)=0.886). Normalized stress showed no relationship with specimens' C-factor. Pairwise comparisons between groups with similar volumes revealed that normalized stress increased at higher C-factors. SIGNIFICANCE: By eliminating the influence of longitudinal compliance, a strong relationship between polymerization stress and specimen volume was revealed in a high compliance testing system.
Assuntos
Polimerização , Estresse MecânicoRESUMO
OBJECTIVE: This study determined the volumetric shrinkage, degree of conversion, sorption, solubility, and flexure properties (before and after aging) of commercial dental composites identified as "low shrinkage". METHODS: Six Bis-GMA-based composites (Point 4, ELS, Filtek Supreme, Aelite LS Posterior, Filtek Z250 and Heliomolar), a silorane-based (Filtek LS) and a dimer dicarbamate dimethacrylate-based composite (N'Durance) were studied. Total shrinkage was measured in a mercury dilatometer (n=3). Elastic modulus and flexural strength was determined by the three point bending test before and after 4 months aging in 75% ethanol solution (n=10). Sorption and solubility in water was assessed according to ISO 4049. Additionally, composite degree of conversion was determined using near-IR spectroscopy (n=3). Data were analysed using one-way/two-way ANOVA or Kruskal-Wallis, and Tukey's test. Student's t-test was used to compare storage periods (α=0.05). RESULTS: The volumetric shrinkage values ranged between 1.5% (Filtek LS) and 3.4% (Point 4). The materials presented different behaviors regarding aging in ethanol, as evidenced by the large range in values of percentage reduction for elastic modulus (26-75%) and flexural strength (25-86%). Sorption values ranged from 8.2µg/mm(3) (Aelite LS Posterior) to 38.2µg/mm(3) (Point 4). Solubility values ranged from -1.5µg/mm(3) (Filtek LS) to 5.7µg/mm(3) (Aelite LS Posterior). The degree of conversion values at 10min ranged between 28% (Filtek LS) and 73% (Point 4). At 72h after curing the values ranged between 39% (Filtek LS) and 83% (Point 4). SIGNIFICANCE: Among the materials identified by their manufacturers as "low shrinkage", only Filtek LS presented statistically lower values of shrinkage compared to composites based on conventional dimethacrylates, but lower degree of conversion as well. Overall materials with higher filler content presented higher initial values of flexural properties. However, their resistance to ethanol degradation seems to be influenced by different compositional factors and, therefore, cannot be directly related to water sorption results.
Assuntos
Resinas Compostas/química , Etanol/química , Metacrilatos/química , Resinas de Silorano/química , Análise de Variância , Módulo de Elasticidade , Teste de Materiais , Solubilidade , Espectroscopia de Luz Próxima ao InfravermelhoRESUMO
We evaluated the effect of activation mode (immediate or delayed light activation vs. no light activation) on diametral tensile strength (DTS), elastic modulus, ultimate tensile strength (UTS), and degree of conversion (DC) in dual-cured resin cements. Three resin cements were evaluated: Enforce, RelyX ARC, and Panavia F. The mixed cements were inserted into circular molds for the DTS test and into dumbbell-shaped molds for the UTS test. Inside the molds, the cements were light-activated either immediately or after 5 min (delayed light activation). If no light activation was performed, the materials were protected from light exposure (control). The DTS and UTS tests were performed until fracture. The elastic modulus was calculated using data from the DTS test, and DC was evaluated 24 h after manipulation using near-infrared spectroscopy. Data for each variable were individually analyzed by two-way ANOVA and the post-hoc Tukey test (α = 0.05). Regarding DTS, activation mode influenced only Panavia Fspecimens, which had the lowest DTS values in the absence of light activation. Activation mode did not influence the elastic modulus or UTS of any resin cement evaluated. Immediate light activation yielded higher DC values as compared with the absence of light activation.
Assuntos
Cimentos de Resina/química , Cimentos de Resina/efeitos da radiação , Análise de Variância , Bis-Fenol A-Glicidil Metacrilato/efeitos da radiação , Análise do Estresse Dentário , Módulo de Elasticidade/efeitos da radiação , Luz , Teste de Materiais , Polietilenoglicóis/efeitos da radiação , Polimerização , Ácidos Polimetacrílicos/efeitos da radiação , Autocura de Resinas Dentárias , Estatísticas não Paramétricas , Estresse Mecânico , Resistência à Tração/efeitos da radiaçãoRESUMO
PURPOSE: To evaluate the effect of mechanical cycling and cementation strategies on the push-out bond strength between fiber posts and root dentin and the polymerization stresses produced using three resin cements. MATERIALS AND METHODS: Eighty bovine mandibular teeth were sectioned to a length of 16 mm, prepared to 12 mm, and embedded in self-curing acrylic resin. The specimens were then distributed into 8 groups (n = 10): Gr1 - Scotchbond Multi Purpose + RelyX ARC; Gr2 - Scotchbond Multi Purpose + RelyX ARC + mechanical cycling; Gr3 - AdheSE + Multilink Automix; Gr4 - AdheSE + Multilink Automix + mechanical cycling; Gr5 - phosphoric acid + RelyX U100 (self-adhesive cement); Gr6 - phosphoric acid+ RelyX U100 + mechanical cycling; Gr7 - RelyX U100; Gr8 - RelyX U100 + mechanical cycling. The values obtained from the push-out bond strength test were submitted to two-way ANOVA and Tukey's test (p = 0.05), while the values obtained from the polymerization stress test were subjected to one-way ANOVA and Tukey's test (α = 0.05). RESULTS: Mechanical cycling did not affect the bond strength values (p = 0.236), while cementation strategies affected the push-out bond strength (p < 0.001). Luting with RelyX U100 and Scotch Bond Multi Purpose + RelyX ARC yielded higher push-out bond strength values. The polymerization stress results were affected by the factor "cement" (p = 0.0104): the self-adhesive cement RelyX U100 exhibited the lowest values, RelyX ARC resulted in the highest values, while Multilink Automix presented values statistically similar to the other two cements. CONCLUSION: The self-adhesive cement appears to be a good alternative for luting fiber posts due to the high push-out bond strengths and lower polymerization stress values.
Assuntos
Cimentação/métodos , Colagem Dentária , Resinas Epóxi/química , Vidro/química , Técnica para Retentor Intrarradicular/instrumentação , Cimentos de Resina/química , Condicionamento Ácido do Dente/métodos , Resinas Acrílicas/química , Animais , Bis-Fenol A-Glicidil Metacrilato/química , Bovinos , Resinas Compostas/química , Materiais Dentários/química , Cavidade Pulpar/ultraestrutura , Dentina/ultraestrutura , Teste de Materiais , Microscopia Eletrônica de Varredura , Ácidos Fosfóricos/química , Polietilenoglicóis/química , Polimerização , Ácidos Polimetacrílicos/química , Distribuição Aleatória , Preparo de Canal Radicular/métodos , Silanos/química , Estresse Mecânico , Propriedades de SuperfícieRESUMO
The organic phase of resin composites is constituted by dimethacrylate resins, the most common monomers being the bisphenol A diglycidildimethacrylate (BisGMA), its ethoxylated version (BisEMA), triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA). This study compared the homopolymers formed from the monomers used in restorative dental composites in terms of their degree of conversion (DC) and reaction kinetics (by near infra-red spectroscopy, n=3), mechanical properties (flexural modulus and strength in three point-bending, FM and FS, respectively, n=15), water sorption and solubility (WS and SL, respectively - ISO 4049, n=5). Materials were made photopolymerizable by the addition of camphoroquinone/dimethylamine ethyl methacrylate. TEGDMA showed the highest DC, followed by BisEMA, UDMA and BisGMA, both at 10 min and at 24h (p<0.001). UDMA showed the highest rate of polymerization, followed by TEGDMA, BisEMA and BisGMA (H0=13.254, p<0.001). UDMA and TEGDMA presented similar FM, significantly higher (p<0.001) than BisEMA and BisGMA, which in turn present statistically similar values (p>0.001). For FS, UDMA presented the highest value (p<0.001), followed by TEGDMA, then by BisEMA and BisGMA, which were statistically similar (p>0.001). BisGMA showed the highest WS, and TEGDMA and BisEMA the lowest. UDMA was statistically similar to all (H0=16.074, p<0.001). TEGDMA presented the highest SL, followed by UDMA, BisGMA and BisEMA (p<0.001). The tested homopolymers presented different behaviors in terms of polymerization kinetics, flexural properties, water sorption and solubility. Therefore, the use of copolymers is justified in order to obtain high DC and mechanical properties, as well as good resistance to water degradation.
A fase orgânica de compósitos resinosos é constituída por dimetacrilatos, sendo os mais comuns o dimetacrilato de diglicidilabisfenol A (BisGMA), sua versão etoxilada (BisEMA), dimetacrilato de trietilenoglicol (TEGDMA) e dimetacrilato de uretano (UDMA). Este estudo comparou os homopolímeros formados pelos monômeros utilizados em compósitos restauradores dentários em relação a seus graus de conversão (GC) e cinética de reação (através de espectroscopia no infra-vermelho), propriedades mecânicas (módulo de elasticidade em flexão e resistência à flexão, MF e RF, respectivamente), sorção de água e solubilidade (SA e SL, respectivamente - ISO4049). Os materiais se tornaram fotopolimerizáveis pela adição de canforoquinona/metacrilato de dimetilaminoetila e foram fotoativados utilizando uma fonte de luz de quartzo-tungstênio-halogênio filtrada para 400-500 nm. O TEGDMA apresentou o maior GC, seguido pelo BisEMA, UDMA e BisGMA, tanto aos 10 min quanto após 24 h (p<0,001). O UDMA mostrou a maior velocidade de reação, seguido pelo TEGDMA, BisEMA e BisGMA (H0=13,254, p<0,001). O UDMA e o TEGDMA apresentaram MF semelhantes, estatisticamente superiores ao BisEMA e ao BisGMA (p<0,001), os quais por sua vez apresentaram valores estatisticamente semelhantes (p>0,001). Para RF, o UDMA apresentou o valor mais alto, seguido pelo TEGDMA, BisEMA e BisGMA (p<0,001), sendo os dois últimos estatisticamente semelhantes (p>0,001). O BisGMA apresentou a maior SA, e o TEGDMA e o BisEMA as menores. O UDMA foi estatisticamente semelhante a todos (H0=16,074, p<0,001). O TEGDMA apresentou a maior SL, seguido pelo UDMA, BisGMA e BisEMA (p<0,001). Os homopolímeros demonstraram desempenhos bastante distintos em relação à cinética de polimerização, propriedades em flexão e sorção e solubilidade. Tais diferenças justificam o uso de co-polímeros para a obtenção de materiais com propriedades físicas otimizadas.