Thesis (doctoral)--Göteborg Universitet, 1993. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (M.D.S.)--University of Hong Kong, 2005.

Orientador: Eduardo Passos Rocha / Banca: Wirley Gonçalves Assunção / Banca: Idelmo Rangel Garcia Júnior / Banca: Paulo Guilherme Coelho / Banca: Paulo Francisco César / Resumo: Proposição. O objetivo do presente trabalho foi avaliar a influência do conceito de plataforma switching na confiabilidade e modo de falha de restaurações unitárias sobre implante com hexágono externo ou interno na região anterior da maxila. Adicionalmente, análises de elementos finitos foram realizadas para avaliar o padrão de distribuição de tensão dentro do complexo pilar-implante e no tecido ósseo peri-implantar. Materiais e Métodos. 84 implantes foram divididos em 4 grupos (n = 21) para realização dos testes de fadiga: SWT-EH e REG-EH (implantes de conexão externa com plataforma switching ou regular, respectivamente); SWT-IH e REG-IH (implantes de conexão interna com plataforma switching ou regular, respectivamente). Análises estatísticas de Weibull foram realizadas considerando as missões de 50.000 ciclos a 210N e 300N. Adicionalmente, foram construídos 4 modelos de elementos finitos considerando as mesmas variáveis para obtenção das tensões equivalentes de von Mises (σvM) no complexo pilar-implante e das máximas tensões principais (σmax) no osso peri-implantar. Resultados. Os valores de Beta para os grupos SWT-EH (1,31), REG-EH (1,55), SWT-IH (1,83) e REG-IH (1,82) indicaram que a fadiga acelerou a falha em todos os grupos. Os valores de confiabilidade calculados para os grupos SWT-EH, REG-EH, SWT-IH e REH-IH foram 0,53 (0,33 - 0,70), 0,93 (0,80 - 0,97), 0,99 (0,93 - 0,99) and 0,99 (0,99 -de tensão estiveram no pilar (SWT-IH = 186 MPa e REG-IH = 88.8 MPa). No osso cortical, os implantes com plataforma switching geraram menor tensão (σmax) tanto para conexão externa (SWT-EH = 49.0 MPa e REG-EH = 56.5 MPa) como para conexão interna (SWT-IH = 37.7 MPa e REG-IH = 45.5 MPa)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Purpose. The aim of the present study was to evaluate the effect of platform switching concept on reliability and failure modes of anterior single-unit restorations for internal and external hex implants. Additionally, finite element analysis were performed to assess the stress distribution within implant-abutment complex and peri-implant bone. Materials and Methods. 84 implants were divided in 4 groups (n=21) for fatigue tests: REG-EH and SWT-EH (regular and switched-platform implants with external connection, respectively); REG-IH and SWT-IH (regular and switched-platform implants with internal connection, respectively). Weibull analysis for a mission of 50,000 cycles at 300N was performed. Additionally, 4 three-dimensional finite element models reproducing the characteristics of specimens used in mechanical tests were created to evaluate the equivalent von Mises stress (σvM) within implant-abutment complex and the maximum principal stress (σmax) in the peri-implant bone. Results. The Beta values for groups SWT-EH (1.31), REG-EH (1.55), SWT-IH (1.83) and REG-IH (1.82) indicated that fatigue accelerated the failure of all groups. The calculated reliability for groups SWT-EH, REG-EH, SWT-IH and REH-IH were 0.53(0.33-0.70), 0.93(0.80-0.97), 0.99(0.93-0.99) and 0.99(0.99-1.00), respectively. Failure modes (screw and/or abutment fracture) were similar for regular and switched-platform implants. Within implant-abutment complex, the higher peak of stress (σvM) was observed in fixation screw (SWT-EH = 190 MPa and REG-EH = 160 MPa) for groups with external hex implants; while for groups with internal hex implants was in abutment (SWT-IH = 186 MPa and REG-IH = 88.8 MPa). In the cortical bone... (Complete abstract click electronic access below) / Doutor

Magister Chirurgiae Dentium - MChD / Objectives: Temperature changes along an implant body have not been widely studied. The objectives of this in vitro study were (i) to establish if the temperature of the abutment influences the temperature of the implant surface, (ii) to establish the temperature transmission from abutment to implant body, and (iii) to establish for what abutment temperature the critical time/temperature threshold of 47oC for 1 minute at implant level is reached. Materials and method: Eight K-type thermocouples were attached to an abutment/implant configuration, mounted in a thermostatically controlled environment. The abutment was exposed to hot water. The temperature at each thermocouple along the implant was logged over a maximum period of 10 minutes using appropriate software. The test was repeated 200 times. A logistic regression model was used for the analysis of the time/temperature databases. Results: There was a positive correlation between the temperatures of the implant and its abutment, albeit with a time delay. Critical threshold values for bone necrosis were reached. The effective dose 50 was estimated at 62.3oC (95% confidence interval estimate): for an abutment temperature of 62.3oC there is a 50% chance that 47oC for 1 minute at implant level is reached. Conclusion: The results of this in vitro study support the hypothesis that abutment temperature is transmitted to a dental implant body. Results of in vitro studies should be interpreted with caution. However, clinicians should be aware of temperature changes along implants and the potential risk associated with this. / South Africa

AIM: This systematic review enumerated the criteria used to determine the survival and success of the rehabilitation of the immediately loaded completely edentulous maxilla with surgically guided implant placement and restoration via fixed prostheses. By identifying these variables, the authors of this review hope to propose a new set of criteria that addresses current expectations of success and facilitates a better comparison of rehabilitation protocols. MATERIALS AND METHODS: The electronic databases PubMed and ScienceDirect were searched for clinical studies of restoration of complete maxillary implant supported fixed dental prostheses. The analysis was confined to prospective studies with a minimum follow-up of 3 years and a minimum number of 10 patients published prior to June 24th, 2021. RESULTS: An initial total of 781 publications was screened from the database searches. After further screening by title and abstract using PRISMA protocol and defined inclusion/exclusion criteria, nine (9) articles were reviewed. Analysis for survival and success criteria resulted in the following: 1. It was difficult to define a conclusion from the selected articles since there was little uniformity as to study design and the criteria used to evaluate the data. 2. High implant and implant supported fixed prosthesis survival could be achieved in the short-term (less than 5 years) when at least 4 implants were placed. 3. The type of surgical guide used for implant placement did not affect the survival and success of implants and implant supported fixed prostheses. 4. Immediate loading of the prostheses did not affect the success and survival of implant and implant supported fixed prostheses. 5. Widely accepted and reproducible criteria should be established to facilitate a better comparison of future materials, rehabilitation protocols. 6. The author proposes the following: Proposed Success Criteria (Ramesh 2023) Successful (Optimal Health): 1. No pain or tenderness associated with function 2. 0 mobility 3. Radiographic bone loss of 20% or less of implant length from initial surgery 4. No bleeding on probing or exudate 5. <4 mild/moderate complications Satisfactory: 1. No pain associated with function 2. 0 mobility 3. Radiographic bone loss 20-40% of implant length 4. Peri-implant mucositis Compromised: 1. May have sensitivity associated with function 2. 0 mobility 3. Radiographic bone loss >40% of implant length 4. Peri-implantitis Failed (clinical or absolute failure): Any of the following: 1. Pain associated with function 2. Mobility 3. Uncontrolled exudate 4. No longer in mouth 5. Non-restorable *This criteria borrows concepts from the Pisa Consensus 200 7. The following list of considerations is necessary to include in all future implant study designs. Proposed necessary factors: 1. Standardized protocols a. Guide design b. Guide fabrication c. Defining conventional versus other methods 2. Maintenance intervals a. Recall with yearly data collection b. Maintenance visits (at least twice yearly) 3. Individual implant review findings 4. Consistent follow up (as previously defined on page 41) a. Must include all the necessary variables to determine implant success 5. Implant location a. Anterior: cuspids and forward b. Posterior: bicuspids and back 6. Implant details - brand, length, diameter 7. Prosthesis design and fabrication, dictated by existing or regenerated bone base

Purpose The present review aimed to evaluate the difference of dental implant failure rates and marginal bone loss (MBL) between implants inserted in fresh extraction sockets or healed sites.   Materials and methods Electronic search was undertaken in three databases, plus manual search of journals, including studies randomized or not. Meta-analyses were performed besides meta-regressions, in order to verify how the odds ratio (OR) and MBL were associated with follow-up time.   Results The review included 163 publications. Altogether, there were 17,278 and 38,738 implants placed in fresh extraction sockets and healed sites, respectively. Pairwise meta-analyses showed that implants in sockets had a higher failure risk in comparison to healed sites: OR 1.349, all studies included; OR 2.070, only prospective non-RCTs; OR 2.487, only RCTs (all p &lt; 0.001). The difference in implant failure between the groups was statistically significant in the maxilla (OR 1.616, p = 0.029), but not in the mandible (OR 2.192, p = 0.075). The MBL mean difference (MD) between the groups was -0.053 mm, although not statistically significant (p = 0.089). There was an estimated decrease of 0.003 in OR (p = 0.284; not statistically significant) and increase of 0.006 mm (p = 0.036) in the MBL MD between groups for every additional month of follow-up.   Conclusion In conclusion, implants placed in fresh extraction sockets present higher risk of failure than implants placed in healed sites. / Syfte Granskningen syftade på att utvärdera skillnaden i misslyckandefrekvensen av dentala implantat och marginalbenförlust (MBL) mellan implantat installerade i ny extraktionsalveol jämfört med läkt områden.   Material och metod Elektronisk sökning gjordes i tre databaser, plus manuell sökning av journaler, inklusive studier som var randomiserade eller ej. Metaanalyser utfördes, förutom metaregressioner, för att verifiera hur oddskvoten (OR) och MBL var associerade med uppföljningstid.   Resultat Granskningen inkluderade 163 publikationer. Sammanlagt fanns det 17,278 och 38,738 implantat placerade i ny extraktionsalveol respektive läkt områden. Parvisa metaanalyser visade att implantat i en ny extraktionsalveol hade en högre risk att misslyckas jämfört med läkt områden. OR 1,349 alla studier inkluderade; OR 2.070, endast prospektiv icke-RCTs, OR 2.487, endast RCTs (alla p &lt; 0.001). Skillnaden i implantatens misslyckandefrekvens mellan gruppen var statistiskt signifikant i maxillan (OR 1.616, p = 0.029), men inte i mandibeln (OR 2.192, p = 0.075). MBL medelskillnaden mellan grupperna var -0,053 mm, och var inte statistiskt signifikant (p = 0.089). Det var en uppskattad minskning med 0.0003 i OR (p = 0.284; inte statistiskt signifikant) och en ökning av 0.006 mm (p = 0.036) i MBL medelskillnaden mellan grupperna för varje ytterligare månad av uppföljning.   Slutsats Slutsatsen blev att implantat som placerades i en ny extraktionsalveol innebar högre risk för misslyckanden än implantat placerade i läkt områden.

published_or_final_version / Dentistry / Master / Master of Dental Surgery

No description available.

Orientador: Idelmo Rangel Garcia Júnior / Coorientador Francisley Ávila Souza / Banca: Ana Paula Farnezi Bassi / Banca: Thallita Pereira Queiroz / Banca: Rodrigo dos Santos Pereira / Resumo: Modificações físicas e/ou químicas das superfícies dos implantes de titânio podem ser realizadas com intuito de facilitar e estimular o processo de osseointegração, consequentemente favorecendo um tempo de reparo mais curto. Sendo assim, o objetivo deste estudo foi avaliar as superfícies de implantes de titânio, modificadas com deposição de β-tricálcio fosfato pelo método biomimético, inseridos na maxila após levantamento de seio maxilar de coelhos, por meio da análise topográfica, biomecânica, microtomográfica, histológica e imunoistoquímica. Dezoitos (18) coelhos da raça Nova Zelândia (Albinus) receberam trinta e seis (36) implantes após elevação da membrana do seio maxilar bilateral. Foram divididos em dois grupos: No Grupo SBF - Implantes com superfícies modificadas pelo tratamento biomimético e preenchimento do seio maxilar esquerdo com coágulo; Grupo TCP - Implantes com superfícies modificadas com deposição de β-tricálcio fosfato pelo método biomimético e preenchimento do seio maxilar direito com coágulo. Os períodos de estudos foram de 7, 15 e 40 dias, onde foram realizadas as avaliações biomecânica, microtomográfica, histométrica e imunoistoquímica. Nas análises físico-químicas de microscopia eletrônica de varredura- MEV, espectroscopia de energia dispersiva- EDS e mapeamento da mineralização observou-se a formação de uma camada de apatita com maiores quantidades de Ca e P nos implantes com deposição biomimética com β-tricálcio fosfato. O teste de molhabilidade monstr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Physical and/or chemical modifications of the surfaces of the titanium implants can be performed in order to facilitate and stimulate the osseointegration process, consequently favouring a shorter repair time. Thus, the objective of this study was to evaluate the surfaces of titanium implants, modified with deposition of β-tricalcium phosphate by the biomimetic method, inserted in the maxilla after lifting the maxillary sinus of rabbits, employing topographic, biomechanical, histological and immunohistochemical analysis. Eighteen (18) New Zealand rabbits (Albinus) received thirty-six (36) implants after bilateral maxillary sinus membrane elevation. They were divided into two groups: In the SBF Group - Implants with surfaces modified by the biomimetic treatment and filling of the left maxillary sinus with clot; Group TCP - Implants with modified surfaces with deposition of β-tricalcium phosphate by the biomimetic method and filling of the right maxillary sinus with clot. The study periods were 7, 15 and 40 days, where the biomechanical, microtomographic, histometric and immunohistochemical evaluations were performed. In the physico-chemical analyzes of scanning electron microscopy (SEM), dispersive energy spectroscopy (EDS) and mapping of mineralization, the formation of an apatite layer with higher amounts of Ca and P was observed in implants with biomimetic deposition with β-tricalcium phosphate. The wettability test showed high hydrophilicity surfaces in this group of impla... (Complete abstract click electronic access below) / Doutor

Orientador: Valfrido Antonio Pereira Filho / Resumo: O presente trabalho teve como objetivo avaliar a qualidade óssea das diferentes regiões alveolares da maxila e da mandíbula por meio da classificação óssea proposta por Leckholm e Zarb (1985) (L & Z), radiografias panorâmicas e periapicais, quociente de estabilidade do implante (ISQ), torque de inserção (TI), microtomografia computadorizada (micro-CT) e histomorfometria. Como objetivo secundário, foi avaliada a correlação entre os diversos métodos citados acima. Foram avaliadas 60 áreas edêntulas, sendo 15 áreas de cada quadrante da maxila e da mandíbula. A qualidade óssea tipo III foi a mais frequente na maxila posterior (73,33%) e anterior (73,33%), já a tipo II foi mais frequente na mandíbula posterior (53,33%) e anterior (60,00%). Foi observada uma diferença estatisticamente significante na densidade óssea óptica avaliada por meio de radiografias periapicais na região posterior da maxila (2,38±1,06) e posterior da mandíbula (3,84±0,68), em relação às demais regiões alveolares avaliadas (p≤0,015). Nas radiografias panorâmicas não foram observadas diferenças entre a densidade óptica das regiões alveolares (p=0,6322). A estabilidade inicial dos implantes instalados na região posterior da maxila foi estatisticamente diferente dos instalados na região posterior da mandíbula, tanto na avaliação por meio do TI como por meio do ISQ (p<0,05). Também foi possível detectar diferenças na qualidade óssea das regiões alveolares da maxila e da mandíbula por meio de vários parâmetros da ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to evaluate the bone quality of the different alveolar regions of the maxilla and mandible through of the classification proposed by Leckholm e Zarb (1985) (L & Z), panoramic and periapical radiographs, implant stability quotient (ISQ), insertion torque (IT), microcomputed tomography (micro-CT) and histomorphometric analysis. The secondary objective was to evaluate the correlation between the several methods mentioned above. Sixty edentulous areas were evaluated, being 15 areas from each quadrant of the maxilla and mandible. The bone quality III was the most frequent in the posterior (73.33%) and anterior maxilla (73.33%) and quality II was the most frequent in the posterior (53.33%) and anterior (60.00%) mandible. A significant statistical difference was observed in the optical bone density evaluated through periapical radiographs of the posterior maxilla (2.38 ± 1.06) and posterior mandible (3.84 ± 0.68), in relation to the other alveolar regions (p≤0.015). With the panoramic radiograph no differences were observed between the optical density of the alveolar regions (p= 0.6322). The primary stability of the implants in the posterior maxilla was different from the posterior mandible, both in the evaluation through the TI and ISQ (p<0.05). It was possible to detect differences in the bone quality of the alveolar regions using several micro-CT parameters (BV, p≤0.002; BV/BT, p≤0.044; BS/TV, p <0.05; Tb.N, p<0.01 and Tb.Sp, p <0.05). With the histometry it was ... (Complete abstract click electronic access below) / Doutor