11 research outputs found
Effect of misfit and prosthetic abutments on straind induced in overdenture-retaining system and in loosening torque of prosthetic screw
No full textOrientadores: Marcelo Ferraz Mesquita, Juliana Maria Costa Nuñez-PantojaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O assentamento passivo de infraestrututuras protéticas é considerado essencial para a longevidade do tratamento reabilitador sobre implantes dentários. O objetivo neste estudo foi analisar o desajuste vertical decorrente da fundição em Ti cp de barras de Overdentures; avaliar as tensões induzidas e torque de afrouxamento do parafuso protético, em infraestruturas protéticas passivas e não-passivas. Foram fundidas vinte barras em Ti cp, retidas por dois implantes, utilizando-se dois tipos de pilares (UCLA e MP), sobre as quais foram avaliadas, utilizando-se microscópio óptico, as desadaptações marginais inerentes à fundição. A quantificação do desajuste seguiu o protocolo do teste do parafuso único (32 Ncm e 10 Ncm). Foram confeccionados 20 index(10 para cada pilar).Os desajustes foram padronizados com a interposição de um anel metálico de 200 µm entre o análogodo pilar A e o cilindro protético. Nesses index, foram avaliados os níveis de desajuste marginal, seguindo o mesmo protocolo utilizado para análise dos desajustes pós-fundição. As aferições das tensões foram realizadas através de extensômetros elétricos fixados aos análogos, após o retorque dos parafusos protéticos. A força necessária para o torque de afrouxamento dos parafusos protéticos de titânio foi medida com torquímetro digital de precisão de 0,1 Ncm. Os resultados foram analisados estatisticamente (ANOVA, teste t (? = 0,05), Correlação de Pearson). Foi encontrada diferença estatística entre os grupos passivos e não-passivos para: porcentagem do torque de afrouxamento (UCLA, p = 0,0087; MP, p = <0,0001); tensão média (MP, p = 0,0192) independente da adaptação e entre as barras desadaptadas (p = 0,0001) qualquer que fosse o pilar utilizado. A correlação de Pearson indicou correlação positiva entre: desajuste x destorque (UCLA, r = 0,6503 e p = 0,0019; MP, r =0,7338 e p = 0,0002);torque de afrouxamento x tensão para UCLA ( r = 0,5373 e p = 0,0145); desajuste e tensão (r = 0,5678 e p = 0,0001). Pode-se concluir que os parafusos protéticos apresentam maior afrouxamento em próteses não passivas. Infraestruturas protéticas desadaptadas induzem maiores níveis de tensão e desajuste vertical quando comparadas com infraestruturas passivas. Pilares UCLAs mostraram os melhores resultados próteses não passivas.Tensão, desajuste vertical e torque de afrouxamento foram fatores correlacionadosAbstract: The passive fit of prosthetic frameworks is considered essential to the longevity of rehabilitation treatment on dental implants.The aim of this study was to analyze vertical misfit of overdentures bars casted in Ti cp; measure the strain, vertical misfit and loosening torque of prosthetic screws, in passive and non-passive frameworks. Twenty bars were casted with Ti cp, retained by two implants, using two types of abutments (UCLA and MA), on which they were evaluated using an optical microscope comparison, the marginal misfit inherent of casting. The misfit quantification followed the protocol of single-screw test (32 Ncm and 10 Ncm). Twenty index were manufactured (10 for each abutment). The misfit were standardized by interposing a metal ring of 200 µm between pilar A abutment and prosthetic cylinder. In the index were evaluated the misfit level, following the same protocol used for measure after casting, and the loosening torque. The measurements of strain were made by strain gauges fixed in the replicas, after retorque of prosthetic screws. The loosening torque of prosthetic screws was evaluated using a digital torque meter with 0.1 Ncm of precision. The results were statistically analyzed (ANOVA, test t, Pearson correlation). Statistical difference was found between passive and non-passive groups: for vertical misfit (p< 0.0001 for both abutments); percentage of loosening torque (UCLA, p = 0.0087; MA, p = <0.0001); mean strain (MA, p = 0.0192) independently of passivity and between the bars desadapted (p = 0.0001) regardless the abutment used. Pearson's correlation (? = 0.05) indicated a positive correlation between: misfit x loosening torque (UCLA, r = 0.6503 e p = 0.0019; MA, r =0.7338 e p = 0.0002); loosening torque x strain for UCLA ( r = 0.5373 e p = 0.0145); misfit x strain (r = 0.5678 e p = 0.0001). It can be concluded: the prosthetic screws have a higher tendency for loosening in ill-fitting prostheses; non-passive frameworks induce higher levels of strain and vertical misfit compared with passive frameworks; UCLA abutments showed the better results in non-passive prostheses; strain, vertical misfit and loosening torque were correlated factorsMestradoProtese DentalMestre em Clínica Odontológic
Características morfológicas dos seios frontal e esfenoidal de indivíduos com oclusão do tipo classe I, II e III de Angle
No full textA força mastigatória é transferida dos dentes para o osso alveolar e
posteriormente é dissipada para outras áreas do neurocrânio, assim como nos seios
paranasais. As características morfológicas desses seios são em parte
determinadas pela interação de fatores genéticos, endócrinos e funcionais.
Funcionalmente, mudanças na direção e na intensidade das forças mecânicas
alteram interna e externamente a estrutura morfológica do tecido. O objetivo desse
estudo foi avaliar cefalometricamente as características morfológicas dos seios
frontal e esfenoidal de indivíduos com oclusão do tipo classe I, classe II e classe III
de Angle com dentição mista. Com auxilio do software Siarcs 3, foi medida a área
do seio frontal e esfenoidal em 75 telerradiografias laterais de pacientes na faixa
etária dos 8 aos 12 anos, sendo 25 classe I, 25 classe II e 25 classe III de Angle. Os
resultados foram submetidos à análise da replicabilidade intra-examinador seguindo
o coeficiente de correlação intraclasse (CCI) (CCI>0,9; p<0,0001), e ao test t de
Student, Mann-Whitney e de Kruskal-Wallis para avaliar diferenças entre os três
grupos estudados. O teste de Mann-Whitney revelou diferença significativa (p<0,05)
nos seios esfenoidais entre os gêneros e, não houve diferenças estatisticamente
significantes entre os seios frontais em ambos os gêneros. Com relação à classe
oclusal e as medidas dos seios frontal e esfenoidal, o teste de Kruskal-Wallis
mostrou que não houve diferenças estatisticamente significantes (p>0,05). A relação
maxilio-mandibular (classes oclusais) não provocam alterações na morfologia dos
seios frontal e esfenoidal, porém o seio esfenoidal tem diferença entre os gêneros.The strength of bite is transferred from the teeth to alveolar bone and is
subsequently dissipated to neurocranium areas, such as the paranasal sinuses. The
morphological characteristics of these sinuses are in part determined by the
interaction of genetic, endocrine and functional factors. Considering functionality,
changes in the direction and intensity of the inside/outside mechanical forces alter
the morphological structure of tissue. The aim of this cephalometric study was to
evaluate the morphological characteristics of frontal and sphenoid sinus in volunteers
with mixed dentition that were classified (Angle) as Class I, Class II or Class III
malocclusion. The area measurements were performed by using the software
SIARCS 3, in lateral radiographs in 75 patients aging from 8 to 12 years, equally
distributed into class I, II or III (Angle). The results were submitted to the intraclass
correlation coefficient (ICC) (ICC> 0.9, p <0.0001), and the Student t, Mann-Whitney
and Kruskal-Wallis tests were used to evaluate the differences among the groups.
The Mann-Whitney test showed significant statistically differences (p <0.05) between
genders considering the sphenoid sinus but not considering frontal sinus. Kruskal-
Wallis test showed no statistically significant differences (p> 0.05) among Angle
classes considering both frontal and sphenoid sinuses. Occlusion (Angle classes)
profile do not cause changes in the morphology of the frontal and sphenoid sinuses,
however the sphenoid sinus was different between the genders
Adaptation and loosening torque of overdentures-bars milled in titanium or casted in different metals alloys
No full textOrientadores: Rafael Leonardo Xediek Consani, Marcelo Ferraz MesquitaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo do estudo foi analisar o desajuste vertical e o torque de afrouxamento de barras para overdentures fundidas em diferentes ligas metálicas ou fresadas em Ti. Uma matriz metálica foi confeccionada em aço inoxidável, simulando o posicionamento de dois implantes na região inter-forames. Dois análogos de implante hexágono externo (plataforma 4,1mm, SIN - Sistema de Implante Nacional S/A, São Paulo, SP, Brasil) foram fixados na matriz metálica com parafusos transversais. Foram confeccionadas 40 barras: 10 fundidas em Ti cp (Ti-C); 10 em NiCr (NiCr-C); 10 em CoCr (CoCr-C) e 10 fresadas em Ti (Ti-M). Para a fundição do titânio foi utilizado equipamentos com jato de gás argônio e vácuo (Discovery -EDG, São Paulo). Para a fresagem do Ti foi utilizado um scanner (Ceramill MAP 400, Amann Girrbach, Curitiba, PR, Brasil) e a uma fresadora (Imes ICORE 450i, Eiterfeld, Alemanha). A desadaptação vertical seguiu o protocolo do teste do parafuso único e mensurações feitas em microscópio óptico comparador microscope (TQ-8800 Torque Meter, Lutron, Taipei, Taiwan) com a utilização de um torquímetro digital meter (VMM-100-BT; Walter UHL, Asslar, Alemanha). A força necessária para o torque de afrouxamento dos parafusos protéticos foi efetuada com torquímetro digital com precisão de 0,1 Ncm, 10 minutos após o retorque (32 N), seguindo a sequência pilar A e B. Os resultados foram analisados estatisticamente (ANOVA e Student-Newman-Keuls) ('alfa' = 0,05). O Ti-M obteve o menor valor para desajuste marginal (47 (8) µm) e NiCr-C o maior valor (209 (10) µm). Quando o mesmo metal (Ti) foi avaliado quanto ao método de fabricação, o Ti-M apresentou o melhor resultado (p <0,01) comparado com o Ti-C (186 (13) µm). O Ti-M apresentou a maior porcentagem para torque de afrouxamento (78 (1) %) e o NiCr-C apresentou a menor porcentagem (59 (10) %). Diferença estatística significativa (p <0,01) foi observada entre Ti-M e Ti-C (65 (1) %). O teste de Pearson mostrou correlação negativa (r = -0.8088), informando que quanto maior for o desajuste menor será a porcentagem do torque de afrouxamento. Foi possível concluir que as barras fresadas em titânio mostraram os menores valores de desadaptação quando comparadas com barras fundidas, enquanto as confeccionadas com Ti mostraram maior estabilidade do parafuso protético quando comparadas com as demais ligasAbstract: The aim of this study was to evaluate the adaptation and loosening torque of overdenture-bars milled or casted in diferente metals alloys. A metallic matrix was made of stainless steel, simulating the positioning of two implants in the inter-foramen region. Two implant analogues of external hexagonal (platform 4,1mm, SIN ¿ National Implant System, Sao Paulo, SP, Brazil) were installed on the models to simulate a bar-clip overdenture using transversal screws. Fourty bars were casted: 10 casted in Ti (Ti-C); 10 casted in NiCr (NiCr-C); 10 casted in CoCr (CoCr-C) and 10 milled in Ti (Ti-M). The milled frameworks were scanned (Ceramill MAP 400, Amann Girrbach Brasil, Curitiba, PR, Brazil) and milled in a Ti alloy block by a CAD/CAM equipment (Imes ICORE 450i, Eiterfeld, Germany). The misfit evaluation followed the protocol of single-screw test using an optical microscope (TQ-8800 Torque Meter, Lutron, Taipei, Taiwan) and a digital torque meter (VMM-100-BT; Walter UHL, Asslar, Germany). The loosening torque of prosthetic screws was evaluated using a digital torque meter, after 10 min of retorque (32 N), following the A and B pilars sequence. The results were statistically analyzed by ANOVA and Student-Newman-Keuls tests ('alpha' = 0,05). Regarding to the metal evaluated, the Ti-M showed the lower value for marginal misfit (47 (8) µm) and NiCr-C showed the higher values (209 (10) µm). When the same metal (Ti) was evaluated for manufacture methods, the Ti-M presents the better results (p<0.01) compared to Ti-C (186 µm). The Ti-M showed the higher percentage of loosening torque (78 (1) %) and NiCr-C showed the lower percentage (59 (10) %). When compared the same metal, there was a statistically significant difference (p<0.01) between Ti-M and Ti-C (65 (1) %). There was an inversely proportional negative correlation (r = -0.8088), the greater is the misfit the smaller is the percentage of loosening torque. The milled (Ti) frameworks showed the better adaptation when compared to the cast frameworks, while Ti bars frameworks showed the better stability for prosthetic screws when compared to other metal alloysDoutoradoProtese DentalDoutor em Clínica Odontológic
Effect Of Vertical Misfit And Clip Material On Stress Distribution Of Overdentures Under Masticatory Loading
No full textFramework 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
Effect of vertical misfit and clip material on stress distribution of overdentures under masticatory loading
No full textFramework 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 clip541015151521sem informaçã
A Modified Technique for Induced Gingival Growth Around Compromised Teeth Prior to Implant Placement: A Report of Two Cases
No full textRegenerative and reconstructive periodontal plastic surgery are important options for treating marginal tissue recession and can be indicated for root coverage or periodontal procedures prior to implant placement. Among the available procedures, periodontal flaps with subepithelial connective tissue graft (CTG) is the most common treatment option to achieve proper tissue manipulation. The present study proposes a modification of a previous technique for inducing spontaneous gingival growth around teeth that will be extracted prior to implant placement, through successive reduction of the buccal root surface. This successive reduction of root surfaces is performed with diamond burs, and such reductions create space for the gingival tissue to grow coronally by reducing root convexity and, consequently, stimulating the healing process with the formation of granulation tissue that will then differentiate into keratinized tissue. The presented technique is suggested to improve the esthetic outcomes for cases involving tooth extraction, implant placement in the extraction socket, and immediate loading with interim restoration and CTG.Department of Periodontics Department of Implantodontics São Leopoldo Mandic, CampinasDepartment of Dentistry Universidade Estadual Paulista (UNESP)Dental Clinic Faculdade de Odontologia de Piracicaba (FOP) UnicampDepartment of Periodontics, São Leopoldo Mandic, CampinasGraduate Program in Dentistry Universidade Federal de Pelotas, Rio Grande do SulDepartment of Restorative Dentistry Universidade Federal de Juiz de ForaFaculty of Dentistry Bauru School of Dentistry (FOB)Department of Dentistry Universidade Estadual Paulista (UNESP
“O ESPORTE NÃO FAZ NADA SOZINHO”: QUALIDADE DE VIDA RELACIONADA À SAÚDE DE ATLETAS ESCOLARES
No full textComparison of the accuracy of different transfer impression techniques for osseointegrated implants
Get PDFThe aim of this study was to evaluate 3 transfer techniques used to obtain working casts of implant-supported prostheses through the marginal misfit and strain induced to metallic framework. Thirty working casts were obtained from a metallic master cast, each one containing 2 implant analogs simulating a clinical situation of 3-unit implant-supported fixed prostheses according to the following transfer impression techniques: group A, squared transfers splinted with dental floss and acrylic resin, sectioned, and re-splinted; group B, squared transfers splinted with dental floss and bis-acrylic resin; and group N, squared transfers not splinted. A metallic framework was made for marginal misfit and strain measurements from the metallic master cast. The misfit between the metallic framework and working casts was evaluated with an optical microscope following the single-screw test protocol. In the same conditions, the strain was evaluated using strain gauges placed on the metallic framework. The data were submitted to one-way analysis of variance followed by the Tukey test (α = 5%). For both marginal misfit and strain, there were statistically significant differences between groups A and N (P < .01) and groups B and N (P < .01), with greater values for group N. According to the Pearson test, there was a positive correlation between the misfit and strain variables (r = 0.5642). The results of this study showed that the impression techniques with splinted transfers promoted better accuracy than the nonsplinted technique, regardless of the splinting material used41666266
Resíduos líquidos gerados na Faculdade de Odontologia: descarte correto
No full textUniversidade Estadual Paulista (UNESP), Departamento de Diagnóstico e Cirurgia, Faculdade de Odontologia de AraraquaraUniversidade Estadual Paulista (UNESP), Departamento de Materiais Odontológicos e Prótese, Faculdade de Odontologia de AraraquaraUniversidade Estadual Paulista (UNESP), Departamento de Diagnóstico e Cirurgia, Faculdade de Odontologia de AraraquaraUniversidade Estadual Paulista (UNESP), Departamento de Materiais Odontológicos e Prótese, Faculdade de Odontologia de Araraquar
Comparison Of Different Transfer Impression Techniques Accuracy For Osseointegrated Implants.
No full textAbstract The aim of this study was to evaluate three transfer techniques used to obtain working casts of implant-supported prostheses through the marginal misfit and strain induced to metallic framework. Thirty working casts were obtained from a metallic master cast, each one containing two implant analogues simulating a clinical situation of three-unit implant-supported fixed prostheses, according to the following transfer impression techniques: Group A, squared transfers splinted with dental floss and acrylic resin, sectioned and re-splinted; Group B, squared transfers splinted with dental floss and bis-acrylic resin; and Group N, squared transfers not splinted. A metallic framework was made for marginal misfit and strain measurements from the metallic master cast. The misfit between metallic framework and the working casts was evaluated with an optical microscope following the single-screw test protocol. In the same conditions, the strain was evaluated using strain gauges placed on the metallic framework. The data was submitted to one-way ANOVA followed by the Tukey's test (α=5%). For both marginal misfit and strain, there were statistically significant differences between Groups A and N (p<0.01) and Groups B and N (p<0.01), with greater values for the Group N. According to the Pearson's test, there was a positive correlation between the variables misfit and strain (r=0.5642). The results of this study showed that the impression techniques with splinted transfers promoted better accuracy than non-splinted one, regardless of the splinting material utilized
