OBJECTIVES: To evaluate and compare the magnitude and distribution of stresses generated on implants, abutments and first molar metal-ceramic crowns using finite element analysis. METHODS: Preliminary three-dimensional models were created using the computer-aided design software SolidWorks. Stress and strain values were observed for two distinct virtual models: model 1 - Morse taper and solid abutment; model 2 - Morse taper and abutment with screw. A load (250 N) was applied to a single point of the occlusal surface at 15° to the implant long axis. Von Mises stresses were recorded for both groups at four main points: 1) abutment-retaining screws; 2) abutment neck; 3) cervical bone area; 4) implant neck. RESULTS AND CONCLUSION: Model 1 showed a higher stress value (1477.5 MPa) at the abutment-retaining screw area than the stresses found in model 2 (1091.1 MPa for the same area). The cervical bone strain values did not exceed 105 µm for either model.
Resumo Introdução A perda dentária é um distúrbio de saúde dos idosos que pode levar à deficiência mastigatória e riscos nutricionais, induzindo alterações bioquímicas da síndrome metabólica (SM). Objetivo Verificar a relação entre número de dentes, medidas antropométricas e SM em um grupo de idosos. Material e método O estudo foi desenvolvido na cidade de Porto Alegre, RS, Brasil, e foi dividido em três fases. A primeira fase coletou informações do banco de dados de todos os participantes do projeto e a segunda coletou dados sociodemográficos, antropométricos e bioquímicos. A terceira fase foi dividida em duas outras fases: primeiro foram aplicadas entrevistas de saúde bucal aos idosos (281 pacientes avaliados por ligações telefônicas e 23 atendidos em domicílio) e, segundo, 45 pacientes foram selecionados aleatoriamente e convidados a validar os dados obtidos por telefone com exames clínicos orais. A amostra foi composta por 304 indivíduos. Os dados coletados foram tabulados e analisados por meio de testes estatísticos. Resultado Mulheres idosas com perda dentária severa apresentam um risco significativamente maior de desenvolver SM. Assim, a manutenção dos dentes naturais nos idosos é um fator protetor para a síndrome. Conclusão Os achados reforçam a hipótese de que a saúde bucal dos indivíduos, expressa pelo número de dentes, pode comprometer e aumentar o risco de SM em idosos.
Abstract Introduction Tooth loss is a health disorder of the elderly population that may lead to masticatory deficiency and nutritional risks, inducing the biochemical changes of metabolic syndrome (MS). Objective To verify the relationship among number of teeth, anthropometric measurements, and MS in a group of elderly people. Material and method The study was developed in Porto Alegre, RS, Brazil, and it was divided into three phases. The first phase collected information from the database of all project participants and the second one collected sociodemographic, anthropometric, and biochemical data. The third phase was divided into two other phases: first, oral health interviews were applied to the elderly (281 patients evaluated by telephone and 23 visited at home) and second, 45 patients were randomly selected and invited to validate the data obtained by telephone with oral clinical examinations performed by a trained dental surgeon. The sample consisted of 304 individuals. The data collected were tabulated and analyzed using statistical tests. Result Elderly women with severe tooth loss present a significantly higher risk of developing MS. Thus, the maintenance of natural teeth in the elderly is a protective factor for the syndrome. Conclusion The findings support the hypothesis that the oral health of individuals, expressed by the number of teeth, may compromise and increase the risk of MS in the elderly.
Abstract Purpose: To evaluate the influence of subcutaneous injection nicotine in osseointegration process on different implant surfaces. Methods: Twenty-two male rabbits were distributed into two groups according to the subcutaneous injections: (1) nicotine 3 mg/day/kg and (2) 0.9 % NaCI 3 mL/day/kg, three times a day; subgroups were then designated-machined and anodized implants were placed in the right and left tibia bones, respectively. The animals were submitted euthanasia after periods of eight weeks to determine nicotine and cotinine levels, alkaline phosphatase and biomechanical analysis. Results: The plasmatic levels of nicotine and cotinine were 0.5 ± 0.28 ng/mL and 9.5 ± 6.51 ng/mL, respectively. The alkaline phosphatase analyses in blood levels in control group were observed 40.8 ± 11.88 UI/L and 40.75 ± 12.46 UI/L, for the surfaces machined and anodized, respectively. In the test group was observed levels 37.9 ± 4.84 UI/L, for both implant surfaces. No significant differences were observed between control and test groups and between the implant surfaces regarding alkaline phosphatase blood levels. For biomechanics, no significant differences were observed in control group between the machined (25±8.46 Ncm) or anodized (31.2 ± 6.76 Ncm) implants. However, the treatment with nicotine induced higher torque than control in both machined (38.3 ± 13.52 Ncm) and anodized (35.5 ± 14.17 Ncm) implants, with p = 0.0024 and p = 0.0121, respectively. Conclusion: Subcutaneous injection of nicotine following implant insertion didn’t have effect on osseointegration, independently from the implant surface.
OBJECTIVES: This research evaluated detail registration in peri-implant bone using two different cone beam computer tomography systems and a digital periapical radiograph. METHODS: Three different image acquisition protocols were established for each cone beam computer tomography apparatus, and three clinical situations were simulated in an ex vivo fresh pig mandible: buccal bone defect, peri-implant bone defect, and bone contact. Data were subjected to two analyses: quantitative and qualitative. The quantitative analyses involved a comparison of real specimen measures using a digital caliper in three regions of the preserved buccal bone – A, B and E (control group) – to cone beam computer tomography images obtained with different protocols (kp1, kp2, kp3, ip1, ip2, and ip3). In the qualitative analyses, the ability to register peri-implant details via tomography and digital periapical radiography was verified, as indicated by twelve evaluators. Data were analyzed with ANOVA and Tukey’s test (α=0.05). RESULTS: The quantitative assessment showed means statistically equal to those of the control group under the following conditions: buccal bone defect B and E with kp1 and ip1, peri-implant bone defect E with kp2 and kp3, and bone contact A with kp1, kp2, kp3, and ip2. Qualitatively, only bone contacts were significantly different among the assessments, and the p3 results differed from the p1 and p2 results. The other results were statistically equivalent. CONCLUSIONS: The registration of peri-implant details was influenced by the image acquisition protocol, although metal artifacts were produced in all situations. The evaluators preferred the Kodak 9000 3D cone beam computer tomography in most cases. The evaluators identified buccal bone defects better with cone beam computer tomography and identified peri-implant bone defects better with digital periapical radiography.
RESUMO Objetivo Avaliar por meio de densitometria óssea o comportamento de dois fatores que podem inteferir no processo da osseointegração: a nicotina e a texturização superficial dos implantes. Métodos Dezenove coelhos da raça Nova Zelândia (Oryctolagus cuniculus) foram distribuídos aleatoriamente em dois grupos (teste e controle), nos quais foram colocados 38 implantes. Na tíbia direita dos animais foram inseridos dezenove implantes usinados (lisos) de 3,75 mm de diâmetro por 6,0 mm de comprimento e, na tíbia esquerda, dezenove implantes anodizados (Vulcano(r)) nas mesmas dimensões. Foram administradas no grupo teste injeções subcutâneas de nicotina 3ml/dia/kg, três vezes ao dia, o grupo controle recebeu igualmente, três vezes ao dia, solução subcutânea de NaCl (3ml/dia/kg), por oito semanas. Após esse período, procedeu-se a análise densitométrica. Resultados Considerando a densidade óptica (pixels), não houve diferenças estatisticamente significativas entre os tipos de implantes (p = 0.135) bem como entre os grupos (p=0.590). Conclusão A nicotina dentro das condições experimentais empregadas neste estudo e a texturização superficial dos implantes não interferiram na densidade óssea.
ABSTRACT Objective The objective of this experimental study was to evaluate, through bone densitometry, the performance of two factors that may influence the osseointegration process: nicotine and superficial texturization of the implants. Methods Nineteen New Zealand rabbits (Oryctolagus cuniculus) were randomly distributed in two groups (test and control), in which 38 implants were placed. 19 machined implants (flat) 3.75 mm of diameter by 6.0 mm length were placed at the right tibia of the animals and, at the left tibia, 19 anodized implants (Vulcano(r)) with the same dimensions. Subcutaneous injections of nicotine 3ml/day/kg, three times a day were administered in group, group control also received, three times a day, subcutaneous solution of NaCl (3ml/day/kg), for 8 weeks. After this period, the densitometry analysis was performed. Results Considering the optical density (pixels), there were no statistical significant differences between the types of implants (p = 0.135) as well as between groups (p=0.590). Conclusion The nicotine inside the experimental conditions used in this study and the superficial texturization of the implants indicated that they were not influencing bone density.
O propósito deste estudo foi avaliar o potencial proliferativo celular das lesões de líquen plano bucal (LPB) de pacientes sem vírus da hepatite C (VHC) por meio do método AgNOR, comparando-o ao potencial proliferativo celular da mucosa bucal normal de portadores de VHC, tratados ou não com interferon e ribavirina. Um estudo transversal foi realizado para investigar 4 grupos: 10 pacientes VHC+ sem sinais clínicos de LPB que nunca haviam sido tratados para a infecção por VHC - Grupo 1; 10 pacientes VHC+ que estavam sob tratamento com interferon e ribavirina - Grupo 2; 15 pacientes com LPB reticular histopatologicamente confirmado, sem VHC - Grupo 3; e 15 doadores de sangue sem infecção por VHC e sem sinais clínicos de LPB (Grupo 4 - Grupo de Controle). O material celular de todos os grupos foi coletado pela técnica da citologia em base líquida. Então, o material sedimentado de cada paciente foi submetido ao método da impregnação das regiões organizadoras nucleolares pela prata (AgNOR). A contagem das NORs foi realizada em 100 núcleos celulares epiteliais por paciente por meio do programa Image Tool(r). O teste Tukey HSD foi utilizado para comparar o valor médio de NORs entre os grupos e mostrou que a mucosa bucal dos pacientes VHC+ previamente tratados com fármacos anti-VHC (Grupo 2) apresentou maior número médio de NORs por núcleo em relação aos outros (p<0,05). O tratamento anti-VHC pode estar relacionado ao aumento da atividade proliferativa celular da mucosa bucal, aventando uma possível relação entre LPB e pacientes VHC+ tratados com interferon e ribavirina.
The objective of this study was to evaluate the cellular proliferative potential of oral lichen planus (OLP) lesions from patients without hepatitis C virus (HCV) by means of AgNOR method, as well as the cellular proliferative potential of the normal oral mucosa from patients with HCV, treated or untreated by interferon and ribavirin. A cross-sectional study was developed to investigate four groups: 10 HCV+ patients without clinical signs of OLP who had never been treated for HCV infection - Group 1; 10 HCV+ patients that were under interferon and ribavirin treatment - Group 2; 15 patients with reticular OLP lesions histopathologically confirmed, without HCV - Group 3; and 15 blood donors without HCV infection and no clinical signs of OLP GROUP 4 Control Group. The cytological material of all groups was collected by the liquid-based cytology technique. Then, the sedimented material from each patient was filled with the Nucleolar Organizer Regions impregnation by silver method (AgNOR). The count of NORs was performed on 100 epithelial cell nuclei per patient using the Image Tool(tm) software. The Tukey HSD test was used to compare the median value of NORs among the groups and showed that the oral mucosa of HCV+ patients previously treated with anti-HCV drugs (GROUP 2), presented a higher average number of NORs in relation to others (p<0.05). The anti-HCV treatment may be related to increased cell proliferation of oral mucosa, indicating a possible relationship between OLP and HCV+ patients treated with interferon and ribavirin.