RADIOGRAPHIC EVALUATION OF THE SUCCESS OF IMPLANT-SUPPORTED TOTAL PROSTHESES ON CONICAL EXTERNAL HEXAGON IMPLANTS AND 6-MONTH FOLLOW-UP AFTER INSTALLATION OF THE PROSTHESES

The development of dental implants has revolutionized the rehabilitation possibilities for partially or totally edentulous patients. The long-term success of the dental implant depends on osseointegration and this is achieved by the combination of two essential stabilities: primary and secondary. Implant-supported prostheses are a great evolution for these treatments, positively interfering in the quality of life of the population, as they generate function and aesthetics for the patient. Thus, the present study aimed to radiographically evaluate complete dentures supported by an external hexagon conical implant in the anterior region of the mandible. More specifically, to evaluate the feasibility of using these implants in cortical bone of the mandible, to verify the success rate regarding the significance of peri-implant bone loss and to compare peri-implant bone loss between patients.

Halitosis and Pain Threshold of Peri-Implant Tissues: An Observational Cohort Study

Abstract In this study, we aimed to evaluate the halitosis and pain threshold of the peri-implant soft tissues in individuals rehabilitated with implant-supported prostheses. Forty-eight subjects were divided into four groups (n = 12) according to their prosthetic rehabilitation: single-tooth fixed prosthesis, multi-tooth fixed prosthesis, overdentures, and the Brånemark protocol. Halitosis was measured using a halimeter, whereas the pain threshold was measured using Von Frey monofilaments. Measurements were taken before (t0) and 30 days after (t1) placement of healing caps, and at the time of (t2) and 30 days after (t3) prosthetic placement. Halitosis data were analyzed using the chi-square test and Bonferroni correction (p < 0.05). Two-way ANOVA and Tukey's test (p < 0.05) were used to analyze pain threshold data. We noted an association between halitosis and time for the Brånemark protocol [X2(6) = 18.471; p = 0.005] and overdenture groups [X2(6) = 17.732; p = 0.007], and between halitosis and type of prosthesis only at t0 [X2(6) = 12.894; p = 0.045]. The interaction between time and the type of prosthesis significantly interfered with the mean pain threshold values (p = 0.001). At most time points, the majority of participants in each group had clinically unacceptable halitosis. After 30 days of using the prostheses, the overdenture group had a lower pain threshold compared to the Brånemark protocol group.

Resumo Este estudo teve como objetivo avaliar a halitose e o limiar de dor dos tecidos moles peri-implantares em indivíduos reabilitados com próteses implantossuportadas. Um total de 48 indivíduos foram divididos em quatro grupos (n=12), de acordo com as reabilitações: prótese fixa unitária, prótese fixa multidentária, sobredentadura e protocolo de Brånemark. A halitose foi medida com um halímetro, enquanto o limiar de dor foi medido com monofilamentos de von Frey. As medições foram feitas antes (t0) e 30 dias após (t1) a colocação das tampas de cicatrização e no momento (t2) e 30 dias após (t3) a colocação da prótese. Os dados de halitose foram analisados por meio do teste qui-quadrado e correção de Bonferroni (p < 0,05). ANOVA de duas vias e o teste de Tukey (p < 0,05) foram usados para analisar os dados do limiar de dor. Observou-se associação entre halitose e tempo para o protocolo de Brånemark [X2(6) = 18,471; p = 0,005] e grupos overdenture [X2(6) = 17,732; p = 0,007], e entre halitose e tipo de prótese apenas em t0 [X2(6) = 12,894; p = 0,045]. A interação entre o tempo e o tipo de prótese interferiu significativamente nos valores médios do limiar de dor (p = 0,001). Na maioria dos pontos de tempos, a maioria dos participantes de cada grupo apresentava halitose clinicamente inaceitável. Após 30 dias de uso das próteses, o grupo overdenture apresentou menor limiar de dor em comparação ao grupo do protocolo de Brånemark.

Transición de prótesis removible a rehabilitación fija de arco completo sobre implantes: Impacto en el perfil facial. Reporte de caso

El perfil facial de un paciente con prótesis total removible podría no ser óptimo cuando el paciente tiene rebordes óseos conservados tridimensionalmente, planteando la necesidad de una prótesis dentaria y no dentogingival. El objetivo de este reporte es describir la transición y tratamiento de una paciente desdentada maxilar, usuaria de prótesis removible con excesivo soporte labial y disponibilidad ósea favorable. En la planificación se prueban parámetros estéticos mediante una ordenación dentaria sin flanco y en base a esta se planifica una "Cirugía de Implantes Protésicamente Guiada" para rehabilitación fija de arco completo sobre implantes en posiciones 1.6, 1.3, 1.1, 2.1, 2.3 y 2.6. Se concluye que con la técnica descrita se puede realizar una evaluación clínica veraz de la propuesta protésica, lo que se traspasa a la guía radiográfica y quirúrgica. Lo anterior permite consistencia entre planificación, cirugía, provisonalización y prótesis definitiva.

The facial profile of a patient with a complete removable denture may not be optimal when the patient has a three-dimensionally preserved bone ridge, raising the need for a dental rather than dentogingival prosthesis. The objective of this report is to describe the transition and treatment of a maxillary edentulous patient, user of a removable prosthesis with excessive lip support and favorable bone availability. In the planning phase, aesthetic parameters are tested using a dental set-up without flank. Based on this, a "Prosthetically Driven Implant Surgery" is planned for a fixed full-arch implant-supported prosthesis with implants located in 1.6, 1.3, 1.1, 2.1, 2.3 and 2.6. It is concluded that, with the described technique, a truthful clinical evaluation of the prosthetic proposal can be performed, and then transferred to the radiographic and surgical guide. This allows consistency between planning, surgery, provisionalization and final prosthesis.

Prótesis sobre implantes: ¿atornillada o cementada? / Implant supported prosthesis: screw retained or bonded?

El objetivo de este artículo es revisar la evidencia científica existente acerca de los tipos de retención protética fija sobre implantes: atornillada, cementada y cemento-atornillada. Fueron evaluadas sus ventajas y desventajas a fin de facilitar al clínico la elección del sistema de retención en el tratamiento rehabilitador con implantes. Si bien la evidencia científica no es concluyente, la prótesis atornillada presentaría más complicaciones técnicas, y las cementadas, más complicaciones biológicas. Por ello, las prótesis cemento-atornilladas podrían ser en la actualidad una opción de elección, por su versatilidad en la rehabilitación implanto-soportada, combinando las ventajas de cada tipo de retención (AU)

The objective of this article is to review the existing scientific evidence about the different types of retention of fixed prosthetic on implants: screwed, cemented and cement-screwed. The advantages and disadvantages of them were evaluated in order to facilitate the clinician's choice of the retention system in the rehabilitation treatment with implants. Although the scientific evidence is inconclusive, the screwed prosthesis would present more technical complications, while the cemented, more biological complications. Therefore, cement-screwed prostheses could be an option of choice, due to their versatility when rehabilitating an implant, combining the advantages of each type of retention (AU)

Occlusion in implant- At a glance

Objectives: Occlusion is a critical and very important component for the clinical success and longevity of dental implants. This review article focuses on the various aspects of implant protective occlusion. Our scientific literature regarding implant occlusion, particularly in implant-supported fixed dental prostheses remains controversial. Materials and methods: A search strategy was performed in MEDLINE/PubMed, Scopus and Google Scholar with keywords ­ 'implants' and 'occlusion', 'implants' and 'fixed prosthesis, 'implants' and 'fixed dental prostheses', 'implants' and 'partial edentulism', 'implants' and 'complications', 'implants' and 'failures', 'implants' and 'cantilever', 'implants' and 'occlusal load'. Results: 135 articles were retrieved. After hand search a total of 290 articles were identified. Ultimately, 30 articles were selected and summarized and discussed as they met the selection criteria. Conclusion: Most of the available clinical data are controversial. Implant-protected occlusion can be accomplished by decreasing the width of the occlusal table and improving the direction of force. By doing these things, we can minimize overload on bone-implant interfaces and implant prostheses, to maintain an implant load within the physiological limits of individualized occlusion, and ultimately provide long-term stability of implants and implant prostheses. Current clinical practices rely heavily on principles extracted from the natural dentition or removable dental prostheses on complete edentulous patients and on expert opinions.

The incidence of the abutment screw loosening and its affecting factors in posterior implant restorations / 대한치과보철학회지

PURPOSE: This study was to assess clinically the incidence of abutment screw loosening of posterior implant-supported fixed prosthesis and its affecting factors. MATERIALS AND METHODS: 391 implant-supported crowns restored from January 2013 to January 2016 were included in this study. All restorations were fabricated with either a single crowns or a splinted crown, and cemented with temporary cement. The incidence of abutment screw loosening is investigated and gender, restoration position, opposing teeth, restoration type, abutment connection type were assessed as possible factors affecting abutment screw loosening. RESULTS: During the observation period (2 – 5 years), abutment screw loosening was found in 29 restorations (7.4%). It took 3 to 48 months (means 19.5 months) to loose the screw, and three of these implants were fractured. Among the factors considered, there were statistically significant differences at abutment screw loosening rate between molar group (9.4%) and premolar group (2.6%) (P<.019). According to the type of opposing teeth, there were statistically significant differences between nature teeth (74.7%) and implant (25.0%), removable denture (3%) (P<.019). The other possible factors did not have a significant effect on loosening of the abutment. CONCLUSION: The incidence of abutment screw loosening in posterior restoration was 7.4%. Abutment screw loosening were more likely to occur in molars group than premolar group, and according to the opposing teeth, there were the greatest frequency in nature teeth than implant and removal denture. There was a statistically significant difference.

Reabilitação estética associando pilar personalizado sobre implante e laminados cerâmicos - relato de caso / Aesthetic rehabilitation associating personalized abutment on implants and ceramic veneers ­ case report

Reabilitações por meio de coroas implanto-suportadas em pacientes que perderam um elemento dentário em região anterior é uma abordagem bem consolidada e pode ser associada a outras técnicas, como o uso de laminados cerâmicos. No entanto, alcançar um resultado estético satisfatório por meio da associação dessas duas abordagens pode ser um desafio para o clínico e o técnico. Objetiva-se relatar um caso clínico de reabilitação estética por meio de laminados cerâmicos, descrevendo uma técnica de confecção de pilar personalizado para laminados sobre implante. Paciente gênero feminino apresentava falta de harmonia da prótese sobre implante do elemento 21 com os demais dentes superiores e apresentava o anseio pela obtenção de dentes com a aparência mais natural. Elaborou-se um planejamento clínico com a realização de adequação do meio bucal seguida por cirurgia periodontal para correção da margem gengival, troca da coroa sobre implante do elemento 21 por um pilar personalizado para receber um laminado cerâmico e confecção de laminados cerâmicos dos dentes 14 a 24. Esse desenho diferenciado do pilar do elemento 21 foi motivado pela dificuldade de acerto de cor, visando uma aparência natural, uma vez que a espessura da cerâmica utilizada para a confecção dos laminados e das coroas totais, e os substratos em que elas são cimentadas são diferentes. A associação de um pilar personalizado sobre implante aos laminados cerâmicos permitiu uma melhor caracterização de cor, otimizando os resultados estéticos.

Considerations for the Survival of Complete Arch Implant-Supported Zirconia Restorations; Status of Antagonistic Arches and Stress Distribution on Frameworks: A Case Report

This report describes two cases of complete arch implant-supported restorations. The first patient had seven dental implants in each arch with monolithic zirconia frameworks. At four weeks' follow-up, the one-piece maxillary framework was fractured, which was re-designed and re-fabricated using laser-sintered cobalt-chrome alloy. The second patient had four implants in the mandible only. A mandibular monolithic zirconia framework and a maxillary conventional complete denture were fabricated and delivered. At five years' follow-up, the patient reported no significant discomfort. Careful consideration and monitoring of the status of antagonistic arches and stress distribution on zirconia frameworks were suggested for complete arch implant-supported fixed restorations

The impact of oral rehabilitation on quality of life by installing a fixed prosthesis with immediate loading in edentulous mandibles / O impacto da reabiliação bucal na qualidade de vida através da instalação de prótese implanto-suportada sob carga imediata em mandíbulas edêntulas

Objetivo: Este estudo avaliou o impacto da reabilitação bucal na qualidade de vida através da instalação de prótese implanto-suportada sob carga imediata em mandíbulas edêntulas. Material e Métodos: Foi realizado um estudo longitudinal de base ambulatorial reunindo 14 pacientes com idade igual ou superior a 18 anos, atendidos nos cursos de especialização em Implantodontia da Associação Brasileira de Odontologia (Juiz de Fora) e da Faculdade de Odontologia da UFJF. Os participantes foram entrevistados sobre dados de identificação, auto percepção de saúde geral e saúde bucal e dados socioeconômicos. Foi utilizado o Oral Health Impact Profile (OHIP-14). Após o teste de normalidade Kolmogorov-Smirnov os valores de tendência central do OHIP-14 foram comparados pelo teste de Wilcoxon pareado com nível de significância de 5%. Resultados: A pontuação média do questionário de qualidade de vida foi 30,14 (antes) e 48,93 (depois). Houve redução significativa do impacto em todos os domínios no período pós cirúrgico, exceto na limitação funcional que se manteve inalterada. Não foi identificado impacto das dimensões dor física e deficiência pós a instalação de implantes. Conclusão: A reabilitação protética e autopercepção são impactantes na saúde bucal, por isso vale ressaltar a necessidade do cuidado, da observação criteriosa de todos os fatores que possuem influência sob as enfermidades, e não somente aos seus sinais e sintomas. (AU)

Objective: This study assessed the impact of oral rehabilitation with immediate-loading fixed prostheses on the quality of life of patients with mandibular edentulism. Material and Methods: A longitudinal study was conducted on an outpatient basis. The sample included 14 patients over 18 years of age, treated in the Implantology Specialization programs of the Brazilian Dental Association (in Juiz de Fora, Brazil) and the School of Dentistry, Federal University of Juiz de Fora. Participants were interviewed about identification data, self-perceived general health and oral health, and socioeconomic data. The Oral Health Impact Profile (OHIP-14) was used. After the Kolmogorov-Smirnov normality test, the OHIP-14 central tendency values were compared using the Wilcoxon paired test with a 5% significance level. Results: The overall mean found for the quality of life questionnaire was 30.14 (before) and 48.93 (after). There was a significant reduction of impact in all areas in the post-surgical period, except for functional limitation. No impact was identified for the dimensions of physical pain and disability after installing implants. Conclusion: Prosthetic rehabilitation and self-perception have high impact on oral health, thus emphasizing the need for care, careful observation of all the factors that may have an influence on infirmities, and not only their signs and symptoms.(AU)

Full mouth rehabilitation in a patient with partial mandibulectomy using CAD/CAM zirconia framework and monolithic zirconia / 대한치과보철학회지

Defects due to mandibulectomy often cause hard and soft tissue loss and result in esthetic problems and functional disorders such as mastication, swallowing, and pronunciation. After the mandibular reconstruction, several complications including loss of alveolar bone can cause limitations in maintenance or supporting of removable prosthesis. For these patients, implant-supported fixed restorations have been an appropriate prosthetic restorative method. In this case report, we report the patient who underwent mandibulectomy and mandibular reconstruction owing to oral cancer, and then restored the current dentition functionally and aesthetically by applying zirconia frameworks and monolithic zirconia crowns by computer-aided design and computer-aided manufacturing.

Eight-year follow-up of two different removable prostheses using six implants in maxillary edentulous patients / 대한치과보철학회지

An implant-supported fixed dental prosthesis (ISFDP) or an implant-supported overdenture (IOD) are good options when treating a completely edentulous jaw opposing natural teeth. However, an ISFDP for a full arch requires sufficient bone quality and quantity, which limits its application. Meanwhile, using an ISFDP as an abutment of a removable partial denture has been considered recently. This clinical report discusses the treatments applied to two patients with edentulous maxillas and opposing natural teeth: one was treated with an IOD and the other was treated with an ISFDP and removable partial denture. Follow-up and management were performed for 8 years.

Tightening techniques for the retaining screws of universal abutment / Técnicas de aperto para parafusos de retenção do pilar universal

Purpose: This study evaluated the torque maintenance of universal abutment retaining screws using different tightening techniques, and coated or uncoated screws. Material and method: The screws were tightened to implants as following: Control - 32 Ncm torque; H20 - holding 32 Ncm torque for 20 s; R - 32 Ncm torque, repeated after 10 min (retorque); and H20+R - combining the two tightening techniques. Titanium and coated screws were also evaluated. Result: Statistical analysis showed higher maintained torque for titanium screws (p< 0.001). The H20+R technique showed the highest maintained torque (p=0.003), but the H20 technique's maintained torque was similar. Conclusion Titanium screws associating the two tightening techniques can improve maintained torque.

Objetivo: Este estudo avaliou a manutenção do torque de parafusos de retenção do pilar universal utilizando diferentes técnicas de aperto e parafusos com ou sem revestimento. Material e método: Os parafusos foram apertados nos implantes da seguinte forma: Controle - 32 Ncm de torque; H20 - segurando os 32 Ncm de torque por 20 s; R - 32 Ncm de torque, repetido após 10 min (retorque); e H20+R - combinando as duas técnicas de aperto. Foram também avaliados parafusos de titânio com e sem revestimento da rosca. Resultado: A análise estatística mostrou maior manutenção do torque de parafusos de titânio (p< 0,001). A técnica H20+R apresentou a maior manutenção do torque (p=0,003), semelhante a manutenção do torque da técnica H20. Conclusão: Parafusos de titânio combinando as duas técnicas de aperto pode melhorar a manutenção do torque.

Effect of cantilever length and alloy framework on the stress distribution in peri-implant area of cantilevered implant-supported fixed partial dentures

ABSTRACT Because many mechanical variables are present in the oral cavity, the proper load transfer between the prosthesis and the bone is important for treatment planning and for the longevity of the implant-supported fixed partial denture. Objectives To verify the stress generated on the peri-implant area of cantilevered implant-supported fixed partial dentures and the potential effects of such variable. Material and Methods A U-shaped polyurethane model simulating the mandibular bone containing two implants (Ø 3.75 mm) was used. Six groups were formed according to the alloy’s framework (CoCr or PdAg) and the point of load application (5 mm, 10 mm and 15 mm of cantilever arm). A 300 N load was applied in pre-determined reference points. The tension generated on the mesial, lingual, distal and buccal sides of the peri-implant regions was assessed using strain gauges. Results Two-way ANOVA and Tukey statistical tests were applied showing significant differences (p<0.05) between the groups. Pearson correlation test (p<0.05) was applied showing positive correlations between the increase of the cantilever arm and the deformation of the peri-implant area. Conclusions This report demonstrated the CoCr alloy shows larger compression values compared to the PdAg alloy for the same distances of cantilever. The point of load application influences the deformation on the peri-implant area, increasing in accordance with the increase of the lever arm.

Clinical cases of implant-supported fixed dental prosthesis using modified lingual screw system (T-screw system) / 대한치과보철학회지

The implant prosthesis can be divided into the screw retained prosthesis and cement retained prosthesis. Each type has advantages as well as disadvantages which is unfavorable to maintain the implants. To overcome these drawbacks, T-screw system was developed. T-screw system which utilizes a lingual direction of the screw to retain the implant prosthesis, has advantages of retrievability of the prosthesis, passive fit, and possibility to form esthetic and functional occlusal surface. The prior prosthesis which utilized horizontal screws had difficulty in fabrication especially in the case of multiple units, and also limited use with all-ceramic prosthesis. In this case, fabricating the implant prosthesis by using the T-screw system showed superior results in easy maintenance, esthetics, and also functions. In addition, we are to report the method of using the T-screw system in implant prosthesis, such as multiple units of implant prosthesis and all ceramic prosthesis.

Risk indicators related to peri-implant disease: an observational retrospective cohort study

PURPOSE: The aim of the present study was to retrospectively investigate the influence of potential risk indicators on the development of peri-implant disease. METHODS: Overall, 103 patients referred for implant treatment from 2000 to 2012 were randomly enrolled. The study sample consisted of 421 conventional-length (>6 mm) non-turned titanium implants that were evaluated clinically and radiographically according to pre-established clinical and patient-related parameters by a single investigator. A non-parametric Mann-Whitney U test or Kruskal-Wallis rank test and a logistic regression model were used for the statistical analysis of the recorded data at the implant level. RESULTS: The diagnosis of peri-implant mucositis and peri-implantitis was made for 173 (41.1%) and 19 (4.5%) implants, respectively. Age (≥65 years), patient adherence (professional hygiene recalls <2/year) and the presence of plaque were associated with higher peri-implant probing-depth values and bleeding-on-probing scores. The logistic regression analysis indicated that age (P=0.001), patient adherence (P=0.03), the absence of keratinized tissue (P=0.03), implants placed in pristine bone (P=0.04), and the presence of peri-implant soft-tissue recession (P=0.000) were strongly associated with the event of peri-implantitis. CONCLUSIONS: Within the limitations of this study, patients aged ≥65 years and non-adherent subjects were more prone to develop peri-implant disease. Therefore, early diagnosis and a systematic maintenance-care program are essential for maintaining peri-implant tissue health, especially in older patients.

Implant-Supported Removable Partial Denture Improves the Quality of Life of Patients with Extreme Tooth Loss

Abstract: This study aimed to evaluate oral health-related quality of life (OHRQoL) in partially dentate subjects, presenting extreme tooth loss in posterior region with missing post-canines, comparing the use of conventional removable partial dentures (RPDs) and implant-supported RPDs. OHRQoL was measured using the Brazilian version of the Oral Health Impact Profile. Twelve subjects presenting maxillary total and mandibular Kennedy Class I edentulism (mean age 62.6±7.8 years) first received complete maxillary dentures and conventional mandibular free-end RPDs. After two months, the subjects had their OHRQoL assessed. Osseointegrated implants were inserted bilaterally in the mandibular first molar regions, and after four months ball abutments were placed to support the free-end RPD. Two months later, the patients had their OHRQoL reassessed. Wilcoxon signed-rank test was used to evaluate differences in OHRQoL (α=0.05). Results showed improvement in all OHIP-49 domains (p<0.05) after associating implants to the RPD. The mandibular implant-supported free-end RPD significantly improved OHRQoL.

Resumo: Este estudo avaliou a qualidade de vida relacionada à saúde bucal (QVRSB) em indivíduos parcialmente dentados, apresentando perda extrema de dentes na região posterior com ausência de dentes pós-caninos, comparando a reabilitação por meio de próteses parciais removíveis convencionais (PPRs) e PPRs implanto-suportadas. A QVRSB foi mensurada utilizando a versão brasileira do Oral Health Impact Profile (OHIP-49). Doze indivíduos apresentando edentulismo total maxilar e Classe I de Kennedy mandibular (idade média 62,6±7,8 anos) receberam primeiramente próteses totais maxilares e PPRs mandibulares convencionais de extremidade livre. Após dois meses de uso destas próteses, a QVRSB dos voluntários foi avaliada. Implantes osseointegrados foram bilateralmente instalados na região de primeiros molares inferiores e, após quatro meses, pilares do tipo bola foram instalados para suportar a extremidade livre da PPR. Após dois meses a QVRSB dos voluntários foi reavaliada. O teste pareado de Wilcoxon foi utilizado para avaliar as diferenças de QVRSB (α=0,05). Os resultados mostraram melhora em todos os domínios do OHIP-49 (p<0,05) após a associação dos implantes à PPR. PPRs de extremidade livre mandibulares implanto-suportadas melhorou significativamente a QVRSB.

Sistema Cone Morse e utilização de pilares com plataforma switching / Morse Taper System and platform switching abutment application

Os implantes cone morse associados a pilares com plataforma switching têm proporcionado resultados promissores com relação à estabilidade dos tecidos peri-implantares. Isso se deve ao perfil cônico do componente protético, à íntima adaptação na interface implante/pilar e ao menor acúmulo de biofilme bacteriano. Para isso, deve-se levar em consideração o posicionamento infraósseo do implante. Essa configuração implante/pilar possui resistência à fratura superior em relação aos sistemas convencionais e, além disso, devido à manutenção da crista óssea e da diversidade de pilares e componentes protéticos, possibilita reabilitações orais estéticas e biocompatíveis.

Morse taper implants associated with platform switching abutments have provided promising results with respect to the stability of peri-implant tissues. This is due to the conical profile of the abutment, the intimate adaptation at the implant/abutment interface, and to the lower accumulation of bacterial biofilm. For this, it has been proposed the insertion of the implants below the crestal bone level. This implant/ abutment configuration presents higher fracture strength compared to the conventional systems and, in addition, because of the maintenance of crestal bone and the diversity of abutments and prosthetic components, provides aesthetic and biocompatible oral rehabilitations.

Load-Application Devices: A Comparative Strain Gauge Analysis

In view of the low loading values commonly employed in dentistry, a load-application device (LAD) was developed as option to the universal testing machine (UTM), using strain gauge analysis. The aim of this study was to develop a load-application device (LAD) and compare the LAD with the UTM apparatus under axial and non-axial loads. An external hexagonal implant was inserted into a polyurethane block and one EsthetiCone abutment was connected to the implant. A plastic prosthetic cylinder was screwed onto the abutment and a conical pattern crown was fabricated using acrylic resin. An impression was made and ten identical standard acrylic resin patterns were obtained from the crown impression, which were cast in nickel-chromium alloy (n=10). Four strain gauges were bonded diametrically around the implant. The specimens were subjected to central (C) and lateral (L) axial loads of 30 kgf, on both devices: G1: LAD/C; G2: LAD/L; G3: UTM/C; G4: UTM/L. The data (με) were statistically analyzed by repeated measures ANOVA and Tukey's test (p<0.05). No statistically significant difference was found between the UTM and LAD devices, regardless of the type of load. It was concluded that the LAD is a reliable alternative, which induces microstrains to implants similar to those obtained with the UTM.

Considerando os valores relativamente pequenos utilizados em odontologia para os ensaios de carregamento verticais axiais, foi desenvolvido um dispositivo de aplicação de carga (DAC) para substituir a máquina de ensaios universal (EMIC). O objetivo deste estudo foi desenvolver um DAC e compará-lo com a EMIC por meio da utilização de carregamentos axiais e não-axiais. Num bloco de poliuretano foi inserido um implante hexágono externo, o qual foi conectado a um pilar protético esteticone. Sobre o pilar protético foi parafusada uma coifa plástica e um pilar cônico foi modelado em resina acrílica, que foi moldada para a obtenção de dez enceramentos iguais que foram fundidos em níquel cromo. Quatro extensômetros foram diametralmente colados ao redor do implante. Cada corpo de prova foi submetido a cargas axiais central (C) e lateral (L) de 30 kgf, em ambos os dispositivos: G1) DAC/C; G2) DAC/L; G3) EMIC/C; G4) EMIC/L. Os dados (µε) foram analisados estatisticamente pelos testes de ANOVA para medidas repetidas e de Tukey (p<0,05). Não houve diferença estatisticamente significante entre os dispositivos DAC e EMIC, independente do tipo de carga. A aplicação de carga não-axial (NA) determinou um aumento significante de tensões ao redor do implante. Foi concluído que o DAC é uma opção confiável, a qual induz microtensão em implantes de forma semelhante à EMIC.

Effect of cement washout on loosening of abutment screws and vice versa in screw- and cement- retained implant-supported dental prosthesis

PURPOSE: The purpose of this study was to examine the abutment screw stability of screw- and cement-retained implant-supported dental prosthesis (SCP) after simulated cement washout as well as the stability of SCP cements after complete loosening of abutment screws. MATERIALS AND METHODS: Thirty-six titanium CAD/CAM-made implant prostheses were fabricated on two implants placed in the resin models. Each prosthesis is a two-unit SCP: one screw-retained and the other cemented. After evaluating the passive fit of each prosthesis, all implant prostheses were randomly divided into 3 groups: screwed and cemented SCP (Control), screwed and noncemented SCP (Group 1), unscrewed and cemented SCP (Group 2). Each prosthesis in Control and Group 1 was screwed and/or cemented, and the preloading reverse torque value (RTV) was evaluated. SCP in Group 2 was screwed and cemented, and then unscrewed (RTV=0) after the cement was set. After cyclic loading was applied, the postloading RTV was measured. RTV loss and decementation ratios were calculated for statistical analysis. RESULTS: There was no significant difference in RTV loss ratio between Control and Group 1 (P=.16). No decemented prosthesis was found among Control and Group 2. CONCLUSION: Within the limits of this in vitro study, the stabilities of SCP abutment screws and cement were not significantly changed after simulated cement washout or screw loosening.

Implant success rates in full-arch rehabilitations supported by upright and tilted implants: a retrospective investigation with up to five years of follow-up

PURPOSE: The aim of this retrospective study was to investigate the cumulative success rate, the implant survival rate, and the occurrence of biological complications in implants supporting full-arch immediately loaded rehabilitations supported by upright and tilted implants. METHODS: The clinical records and periapical radiographs of patients who attended follow-up visits were collected, and information was recorded regarding marginal bone loss resorption, the occurrence of peri-implant infectious diseases, and the implant survival rate. Implants were classified as successful or not successful according to two distinct classifications for implant success. RESULTS: A total of 53 maxillary and mandibular restorations including 212 implants were analysed, of which 56 implants were studied over the full five-year follow-up period. After five years, the cumulative success rate was 76.04% according to the Misch classification and 56.34% according to the Albrektsson classification. The cumulative implant survival rate was 100%, although one implant was found to be affected by peri-implantitis at the second follow-up visit. CONCLUSIONS: The cumulative success rate of the implants dropped over time, corresponding to the progression of marginal bone resorption. The prevalence of peri-implantitis was very low, and the implant survival rate was not found to be related to the cumulative success rate.