Finite element analysis of stresses in peri-implant bone tissue during osseointegration

Orientador: Rafael Leonardo Xediek ConsaniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Forças aplicadas por próteses totais a implantes submersos durante o período deosseointegração podem, em alguns casos, levar ao insucesso clínico. Até o momento não existe trabalho na literatura que quantifique e/ou verifique a distribuição das forças mastigatórias em implantes submersos durante a ação mastigatória de próteses totais convencionais usadas provisoriamente durante o período de osseointegração. Dessa forma, neste trabalho foram avaliadas as tensões geradas no tecido ósseo subjacente a implantes recém-colocados, em diferentes situações, durante a ação mastigatória em próteses totais convencionais provisórias inferiores, por meio da metodologia dos elementos finitos. Com software de modelagem 3-D (SolidWorks 2010, SolidWorks Corp., Concord, Massachusetts, EUA) foram confeccionados modelos tridimensionais de mandíbula simulando diferentes situações clínicas: (1) implantes submersos, próteses totais convencionais e próteses reembasadas com diferentes materiais reembasadores macios; (2) diferentes níveis de altura de exposição dos cicatrizadores (submerso, nível gengival, 1,5 mm exposto no meio bucal); e (3) diferentes espessuras e comparação entre reembasamento na base da prótese inteira ou somente na região dos implantes. As análises foram realizadas em software específico (ANSYS Workbench 12, Ansys Inc., Canonsburg, Pennsylvania, EUA) e para cada modelo foram simuladas duas situações, com aplicação de carga mastigatória em canino inferior direito (35N) e primeiro molar inferior direito (50N). Todas as análises foram realizadas em tensão máxima principal, em MPa. Os resultados obtidos demonstraram que o reembasamento da prótese com material macio reduziu a concentração de tensões no tecido ósseo peri-implantar, sendo a concentração de tensão diretamente relacionada com a maciez do material. Os cicatrizadores submersos foram os que apresentaram menor valor de concentração de tensões. A espessura e área de reembasamento estão relacionadas à transmissão de tensões ao osso peri-implantar, quando o reembasamento da região dos implantes com espessura de 3 mm apresentou melhores resultados. Comparando-se os resultados mostrados nas diferentes simulações conclui-se que a situação que promoveu menor concentração de tensões no osso peri-implantar foi com implantes submersos, reembasamento realizado somente na região dos implantes, espessura de 3 mm e material macio.Abstract: Forces applied to submerged implants from complete dentures during the osseointegration period can, in some cases, lead to clinical failure. To date there is no study in the literaturethat quantifies and/or verifies the stress distribution of occlusal forces in submerged implants during the masticatory function of conventional complete dentures used on an interim basis during the period of osseointegration. Thus, this study evaluated the stresses in the bone adjacent to newly placed implants during the masticatory function in conventional complete dentures through the finite element methodology. Using a 3-D modeling software (SolidWorks 2010, SolidWorks Corp., Concord, Massachussets, EUA) it were made tridimensional models of a mandible simulating different clinical situations: (1) submerged implants, conventional complete dentures and relined ones with different soft liner materials; (2) different height levels of exposure to the oral environment (submerged, gingival level and 1.5mm of exposure to the oral environment); and (3) different thickness and comparation between relining the entire base or only in the region near the implants. The analysis were made in a specific software (ANSYS Workbench 12, Ansys Inc., Canonsburg, Pennsylvania, EUA) and for each model it were simulated two situations with masticatory load in inferior right canine (35N) and inferior right first molar (50N). All the analysis were made in maximum principal stress, in MPa. The obtained results showed that relined dentures with soft liner material reduced the stress concentration in the peri-implant bone tissue, being the stress concentration directly related to the softness of the material. Submerged implants presented the lowest values of stress concentration in the peri-implant bone tissue. The thickness and the area of reline are related to the transmission of stress to the peri-implant bone tissue, when relining the denture only in the region of the implants with a 3-mm thick layer of soft liner material presented better results. Comparing the results obtained from the different simulations it is possible to conclude that the situation which promoted fewer stress concentration in the peri-implant bone was with submerged implants, relining made only in the implants region, thicker layer (3 mm) of reline and softer material.DoutoradoProtese DentalDoutor em Clínica Odontológic

Evaluation of health parameters, use of drugs, and alcohol intake among an elderly population in São José dos Campos, SP, Brazil

AIM:To evaluate health parameters (blood pressure, heart rate and blood glucose), the use of medicines and alcohol consumption in elderly residents in the city of São José dos Campos, SP, Brazil.METHODS:A sample of 500 elderly individuals (98 men and 402 women, with mean age of 69.5 years) was examined. Personal data and medicines used by the patients were recorded, general health aspects were assessed and the Alcohol Use Disorders Identification Test (AUDIT) was applied to survey alcohol consumption.RESULTS:Two hundred and four patients (40.8%) presented high blood pressure and 93 patients (18.6%) had hyperglycemia. The most used pharmacological groups were antihypertensive drugs, antilipidemics, drugs to control hypothyroidism and hypoglycemic agents. Possible pharmacological interactions with alcohol were present in 60.9% of the used medicines. The AUDIT results showed that 91% of the sample presented a low-level intake of alcohol and only 1% presented characteristics of alcohol addiction. Associations were found among AUDIT scores with age (p=0.037), since a larger number of alcohol addicts were found among younger patients, and use of drugs (p=0.046), since patients who consumed more daily medicines made less use of alcohol (low-level).CONCLUSIONS:The studied sample presented a high prevalence of hypertension and relatively low incidence of diabetes. A low use of drugs was verified and women made more use of daily medications than men. Low alcohol consumption was also observed, and women consumed less alcohol than men.768

Movimentação de Dentes em Prótese Total: Revisão da Literatura

Objetivos: A movimentação de dentes durante o processamento daprótese é de grande importância e merece atenção tanto dos profissionaisque a confeccionam quanto dos pesquisadores para se conseguiras menores alterações dimensionais e o melhor desempenho clínicopossível. Desta maneira o objetivo do presente estudo foi revisar a literaturasobre a movimentação de dentes artificiais em próteses totais.Método: Para a realização do estudo foi utilizada uma coletânea de trabalhoscientíficos, analisados por meio de Revisão da Literatura, verificandoassim os diferentes fatores que causam a movimentação dedentes artificiais.Resultados e conclusão: A movimentação de dentes artificiais em prótesestotais é inevitável podendo diminuir de intensidade, porém nãopode ser eliminada completamente durante a confecção da prótese

Photobiomodulation therapy reduces postoperative pain after third molar extractions:a randomized clinical trial

To assess the efficacy of PBMT on reducing postoperative pain scores in patients submitted to third molar extractions. A randomized controlled trial (ReBEC:RBR-94BCKZ) was designed according to the SPIRIT and followed the CONSORT. Patients were randomly allocated according to control or PBMT groups. PBMT consisted of the application of GaAlAs laser (808nm;50mW) applied in six points (1.23 min;11 J/cm2) after extraction. Pain scores were assessed using the Visual Analogue Scale (VAS) in millimeters evaluated after 6 (T6), 24 (T24), and 48 (T48) hours. The Wilcoxon Mann?Whitney test was used to check for possible associations between VAS scores and treatment groups. A total of 101 third molar extractions were performed in 44 patients. The mean age was 28 years old(SD±11.54). Comparing control and intervention, PBMT group showed a significant effect on the reduction of postoperative pain at T6(mean VAS=0.9; C.I:0.63?1.16) compared to control (mean VAS=2.5;C.I:2.1?2.88)(p<0.001). The same statistically significant effect on the reduction of postoperative pain was observed at T24 (PBMT mean VAS=0.72;C.I:0.51?0.93; control mean VAS=2.86;C.I:2.40?3.31;p<0.001) and T48 (PBMT mean VAS=0.64;C.I:0.36?0.92; control mean VAS=2.86;C.I:2.37?3.34;p<0.001). PBMT significantly reduce the postoperative pain scores when assessed 6, 24, and 48 hours after third molar extractions

Evaluation Of Health Parameters Use Of Drugs And Alcohol Intake Among An Elderly Population In São José Dos Campos Sp Brazil

Aim: To evaluate health parameters (blood pressure, heart rate and blood glucose), the use of medicines and alcohol consumption in elderly residents in the city of São José dos Campos, SP, Brazil. Methods: A sample of 500 elderly individuals (98 men and 402 women, with mean age of 69.5 years) was examined. Personal data and medicines used by the patients were recorded, general health aspects were assessed and the Alcohol Use Disorders Identification Test (AUDIT) was applied to survey alcohol consumption. Results: Two hundred and four patients (40.8%) presented high blood pressure and 93 patients (18.6%) had hyperglycemia. The most used pharmacological groups were antihypertensive drugs, antilipidemics, drugs to control hypothyroidism and hypoglycemic agents. Possible pharmacological interactions with alcohol were present in 60.9% of the used medicines. The AUDIT results showed that 91% of the sample presented a low-level intake of alcohol and only 1% presented characteristics of alcohol addiction. Associations were found among AUDIT scores with age (p=0.037), since a larger number of alcohol addicts were found among younger patients, and use of drugs (p=0.046), since patients who consumed more daily medicines made less use of alcohol (low-level). Conclusions: The studied sample presented a high prevalence of hypertension and relatively low incidence of diabetes. A low use of drugs was verified and women made more use of daily medications than men. Low alcohol consumption was also observed, and women consumed less alcohol than men.13176-8

Influence of different flask types on teeth displacement in complete upper dentures

Orientador: Rafael Leonardo Xediek ConsaniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiraciabaResumo: O objetivo neste estudo foi verificar a influência de diferentes tipos de muflas na movimentação de dentes ocorrida em próteses totais padronizadas após o processamento laboratorial em ciclo de polimerização longo (74±2°C por 9 horas), em banho de água. A partir de matrizes em silicone, foram obtidos 31 modelos em gesso pedra tipo III de uma arcada desdentada superior e 31 de uma inferior. Sobre um modelo superior foram confeccionada base de prova e plano de orientação em cera com dimensões de 20 mm de altura na região anterior e 10 mm na região posterior. Este plano foi montado em articulador semi-ajustável, e após isso foi confeccionada base de prova e plano de cera inferior seguido pela montagem do modelo inferior no articulador. Após a realização da montagem dos dentes artificiais nos planos de cera, foi confeccionada uma matriz em silicone laboratorial para possibilitar a reprodução da montagem dos dentes. Foram então encerados 30 pares de próteses totais, distribuídos aleatoriamente em três grupos (n=10): Mufla convencional, Mufla Dupla e Mufla HH com os dentes em oclusão. Antes da inclusão pinos referenciais foram colocados em locais padronizados e as distâncias entre incisivos (I-I), pré-molares (P-P), molares (M-M), incisivo a molar do lado esquerdo (IE-ME) e incisivo a molar do lado direito (ID-MD) aferidas em microscópio óptico linear com 0,0005 mm de precisão. Após a polimerização estas distâncias foram aferidas novamente, e os dados obtidos analisados estatisticamente através dos testes t-pareado, ANOVA e Holm-Sidak, todos com 95% de confiança. Foram encontradas diferenças estatisticamente significantes entre as distâncias P-P (p=0,003 para mufla dupla; e p<0,001 para mufla HH) e M-M (p=0,006 para mufla convencional; p=0,005 para mufla dupla; e p<0,001 para mufla HH). Quando comparadas entre si, foi encontrada diferença estatisticamente significante entre pré-molares (p=0,011) sendo que a mufla convencional apresentou menor diferença entre as distâncias pré/pós-polimerização que a mufla HH (p=0,003). Todas as muflas envolvidas neste estudo apresentaram diferenças estatisticamente significantes em ao menos uma das distâncias aferidas, sendo que a mufla convencional apresentou os melhores resultadosAbstract: The aim of this study was to verify the influence of different flask types in the teeth displacement after processing standardized complete dentures in long cycle of polymerization in water bath (9 hours at 74°C). Thirty-one superior and thirty-one inferior stone casts of an edentulous arch were poured with type III stone, from a silicone matrix. One superior cast was mounted in a semi-adjustable articulator with wax rim height of 20 mm in anterior region and 10 mm in the posterior, and then the inferior cast was mounted too. After teeth wax-up, silicone matrix were made with laboratory silicone to enable the reproduction of the same wax-up pattern. The dentures were assigned randomly in 3 groups (n=10): Traditional flask, Double Flask and HH flask with teeth in occlusion. Before flasking reference pins were placed in standardized places and the distances between incisive (I-I), pre-molars (P-P), molars (M-M), left incisor to left molar (LI-LM) and right incisor to right molar (RI-RM) were measured in an optical microscope with 0.0005 mm accuracy. After polymerization, these distances were re-measured and the data obtained was statistical analyzed trough paired t-test, ANOVA and Holm-Sidak, all with 95% of confidence level. It was found statistical differences among P-P (p=0.003 for double flask; and p<0.001 for HH flask) and M-M (p=0.006 for traditional flask; p=0.005 for double flask; and p<0.001 for HH flask). When compared, it was found statistical differences among pre-molars (p=0.011) where conventional flask showed minor differences than HH flask (p=0.003). All flask types used in this study presents statistical differences in at least one of the measured distances, being that traditional flask showed better resultsMestradoProtese DentalMestre em Clínica Odontológic

Effect Of Vertical Misfit And Clip Material On Stress Distribution Of Overdentures Under Masticatory Loading

Framework misfit is a common problem observed in overdentures, which might result in prosthetic and biological complications. The aim of this study was to evaluate the influence of vertical misfit and clip material on the stress distribution in an overdenture-retaining bar system under masticatory loading. A 3-D finite element model of a resorbed jaw was created, including two implants and a bar-clip retained overdenture. A pressure of 100 MPa was applied to the right mandibular first molar. Different vertical misfit levels (50, 100, and 200 A mu m) and clip materials (plastic or gold) were evaluated. Data were evaluated using von Mises stress and microstrain. Vertical misfit amplification caused an increase in the microstrain values in the peri-implant bone tissue next to the ill-fitted component and increased the stresses in the prosthetic screws. The clip material influenced the stress and microstrain distribution in the prosthetic components and bone tissue. The levels of vertical misfit seem to be closely linked with the stress values in the prosthetic screws, mainly to that of the ill-fitted component. The gold clip presented an increase in the stress compared to the plastic clip.54101515152

Influence Of Diamondlike Carbon Coating Of Screws On Axial Tightening Force And Stress Distribution On Overdenture Bar Frameworks With Different Fit Levels And Materials

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Purpose: The aim of this study was to evaluate the axial tightening force applied by conventional and diamondlike carbon (DLC)-coated screws and to verify, through three-dimensional finite element analysis (FEA), the stress distribution caused by different framework materials and prosthetic screws in overdenture frameworks with different misfit levels. Materials and Methods: The axial tightening force applied by the screw was evaluated by means of a titanium matrix connected to a load cell. Conventional titanium or DLC-coated screws were tightened with a digital torque wrench, and the load values were recorded. The values were applied in an FEA to a bar-clip attachment system connected to two 4.0 x 11-mm external-hexagon titanium implants placed in an anterior edentulous arch. DLC-coated and conventional screws were modeled with their respective axial forces obtained on the experimental evaluation for three bar framework materials (titanium, nickel-chromium, and cobalt-chromium) and three levels of misfit (100, 150, and 200 mu m). Von Mises stresses for prosthetic components and maximum principal stress and microstrains (maximum principal strains) for bone tissue were measured. Results: The mean force applied by the conventional screw was 25.55 N (+/- 1.78); the prosthetic screw coated with a DLC layer applied a mean force of 31.44 N (+/- 2.11), a statistically significant difference. In the FEA, the DLC screw led to higher stresses on the framework; however, the prosthetic screw suffered lower stress. No influence of screw type was seen in the bone tissue. Conclusion: Titanium frameworks reduced the stress transmitted to the bone tissue and the bar framework but had no influence on the screws. Higher misfit values resulted in an increased stress/strain in bone tissue and bar framework, which was not the case for retention screws.30510191027Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2012/19374-5

Patients' Perceptions of Benefits and Risks of Complete Denture Therapy

Made available in DSpace on 2019-09-12T16:56:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2014PurposeThe aim of this study was to assess patients' perceptions of benefits and risks concerning complete denture therapy. A secondary objective was to assess the influence of clinical and sociodemographic variables on patients' perceptions. Materials and MethodsThe sample was composed of 104 volunteers who presented themselves for complete denture treatment at a dental school. The average age of the volunteers was 69.2 years () 9.3. Patient opinions concerning the benefits of complete denture therapy were recorded using a previously reported questionnaire. The answers were evaluated in three domains: (1) benefits (positive perceptions); (2) risks (negative perceptions); and (3) consequences of no treatment. ResultsThe average time of use of the previous dentures was 20 years (SD +/- 12.9). Risk factors (negative perceptions) received lower scores by the patients, while the consequences of no treatment received higher scores. No association was found among evaluations of the previous dentures and educational level, marital status, and gender; however, patients' evaluation about their previous dentures was significantly different depending on age (p= 0.001) and previous dentures' time of use (p= 0.038). ConclusionsPatients presented a positive perception of complete denture therapy, and the risk factors (negative perceptions) received the lowest scores. Patient perception regarding complete denture therapy was not influenced by educational level, evaluation of the previous dentures, or marital status.[Miranda, Barbara Barberio] Universidade de Taubaté (Unitau), Sch Dent[Fernandes dos Santos, Mateus Bertolini] Univ Estadual Campinas, Piracicaba Dent Sch, Sao Paulo, Brazil[Marchini, Leonardo] Univ Iowa, Coll Dent, Dept Prevent & Community Dent, Iowa City, IA 52242 US