Streptococcus mutans adhesion and releasing of metallic ions in dental alloys

Abstract Aim: To evaluate the adherence of Streptococcus mutans to the surface of the amalgam and copper/aluminum alloy samples and also evaluate the release of metallic ions. Methods: The prepared medium was changed every 72 h and analyzed by atomic absorption spectrophotometer. Samples were removed from the prepared medium at 15, 30, 48 and 60 days. Results: The result shows that ions released were statistically different among all groups, and so were both biofilm and pits formation and the corrosion induced by the S. mutans in both types of samples. SEM observation of the samples immersed in the prepared medium with S. mutans showed adherence of microorganisms on the whole surface, in all groups. Conclusions: The S. mutans adhere to both amalgam and copper/aluminum alloy causing corrosion of those restorations. S. mutans produced a greater ions release in Cu/Al alloy; in amalgam, the ions release was not influenced by exposure to S. mutans

Análise dos aspectos biomecânicos e biológicos na reabilitação oral com união dente/implante

The consequences as well the criteria for the prosthetic oral rehabilitations with tooth/implant connection come in the literature, in most of the cases, with controversial results. On one side, many studies consider the connection viable, while the others studies consider impracticable because of the difference biomechanics and physiologic of the two systems. The purpose of this study was to organize, to synthesize and to select literary studies that can standardize solutions when this rehabilitation type is necessary. The study showed that the clinical follow-up result in a high survival rate in a short period and the bioengineering studies did not accept the tooth/implant connection.Os critérios bem como as conseqüências das reabilitações orais protéticas envolvendo união de dentes a implantes osseointegrados apresentam na literatura resultados controversos. Por um lado, alguns estudos consideram viável a união de elementos dentais com implantes, enquanto outros a condenam, visto a diferença biomecânica e fisiológica dos dois sistemas. Deste modo, este trabalho teve como objetivo selecionar estudos literários que possam padronizar soluções quando esse tipo de reabilitação for necessária. O levantamento mostrou que a maioria dos estudos aplicados à bioengenharia condena a união enquanto os estudos longitudinais clínicos resultam em baixo índice de fracasso, entretanto, em curto período de acompanhamento

Influence of torque and bone type on stability quotient of two implant platforms: a clinical trial

Abstract The objective of this study was to analyze the influence of insertion torque, bone type, and peri-implant bone loss on implant stability quotient (ISQ) of cylindrical external hexagon (EH) and Morse Taper (MT) implants. Forty-four single implants were placed in the edentulous areas of 20 patients who met the inclusion and exclusion criteria. Immediately after implant placement (t1) and after osseointegration (four and six months for mandible and maxilla, respectively) (t2), insertion torque, resonance frequency, and peri-implant bone loss were measured using probing depths and digital periapical radiography. A significant difference was noted in the ISQ values between t1 and t2 in type III bone for EH and MT implants. No significant difference in bone loss values was observed when comparing bone types for EH or MT in all evaluated sites. Based on marginal bone loss assessed using radiography, there was no significant difference between the MT and EH groups. A positive correlation between torque and ISQ t1 value was observed for MT (correlation: 0.439; p = 0.041) and EH (correlation: 0.461; p = 0.031) implants. For EH and MT implants, the greater the insertion torque, the greater was the ISQ value (moderately positive correlation). A weak negative correlation was found between bone type and ISQ t1 for MT implants. Contrarily, no correlation was observed between bone type and ISQ t1 for EH implants. In all cases, bone loss around the implants was clinically normal

Avaliação fotoelástica de overdentures mandibulares sobre implantes com três diferentes sistemas de retenção e prótese protocolo de Branemark

Objetivo: O propósito deste estudo foi avaliar o padrão de tensão produzido por overdentures implanto-retidas com 3 diferentes sistemas de retenção e prótese fixa tipo protocolo de Branemark, através do método da fotoelasticidade. Método: O modelo mandibular foi confeccionado em resina fotoelástica PL-2 contendo 4 implantes 3.75x10mm, posicionados na área interforaminal. Foram avaliadas 4 situações clínicas: A- Overdenture com 3 attachments clip sobre barra; B- Overdenture com 2 attachments Era em cantilever aos últimos implantes e 1 clip anterior; C- Overdenture com 3 attachments O’ring sobre barra e D- Prótese total fixa tipo protocolo de Branemark. Forças oclusais verticais de 100N foram aplicadas entre os incisivos centrais e unilateralmente nos segundos premolares direito e esquerdo e segundos molares direito e esquerdo para todos os sistemas. Na prótese protocolo foram aplicadas cargas verticais nos primeiros molares a fim de permitir análise da extensão do cantilever. As tensões desenvolvidas nas estruturas de suporte foram monitoradas fotoelasticamente e registradas fotograficamente. Resultados: No carregamento anterior, houve alta concentração de stress nos implantes medianos na situação A, principalmente na região apical. O carregamento no premolar gerou alto stress no implante ipsilateral à aplicação da carga com maior intensidade para a prótese protocolo e situação A. No carregamento do molar, a overdenture com 3 o’ring distribuiu o stress de forma mais uniforme sobre o rebordo alveolar, com menor sobrecarga ao implante distal. O aumento do cantilever na prótese protocolo causou grande stress ao último implante e tração no implante mediano. Todas as situações avaliadas demonstraram baixa transferência de stress ao nível do pescoço dos implantes contralaterais à aplicação da carga. Conclusão: As forças verticais...Objective: The purpose of this study was to evaluate of stress patterns produced by mandibular implant overdentures with three different attachment systems and fixed implant prosthesis, through the photoelastic method. Method: A mandibular model was fabricated PL-2 photoelastic resin having 4 screw-type implants (3.75 × 10 mm) embedded in the parasymphyseal area. Four clinical situations were evaluated: A - Overdenture with 3 plastic Hader clips on bar; B - Overdenture with 2 ERA attachment was in cantilever to the terminal implant and 1 anterior Hader clip; C - Overdenture with 3 ball/O-ring attachment on bar and D - implant-supported fixed partial denture (FPD). Vertical occlusal forces from 100 N were applied between of central incisor and unilaterally to the right and left second premolars and second molars for all the designs. In FPD were applied vertical loads in the first molars in order to allow analysis of the cantilever extension. Stresses that developed in the supporting structure were monitored photoelastically and recorded photographically. Results: Anterior loading, there was high stress concentration in medium implant in the situation A, mainly apical area. The premolar loading generated high stress to the ipsilateral implants with larger intensity from the FPD and situation A. The molar loading, the overdenture with 3 ball/O-ring attachment away the caused more uniform stress distribution in the posterior edentulous ridge with less overload in the terminal implant. The FPD cantilever increase caused high stress to the terminal implant and traction to the medium implant. All the situations demonstrated a low stress transfer at the level of the contralateral implants neck. Conclusion: Vertical forces applied to the bar-clip overdenture and FPD created immediate stress patterns of greater magnitude and concentration on ipsilateral implants while the ball/O-ring... (Complete abstract click electronic access below

Influência do processamento de próteses totais maxilares com diferentes espessuras da base: análise gráfica da movimentação dos dentes artificiais

A relação existente entre os métodos de processamento das resinas acrílicas e a espessura de resina das bases de dentaduras, bem como a associação com o tamanho e forma do arco maxilar, tem sido um assunto bastante discutido no que diz respeito à possíveis alterações no posicionamento dos dentes e selamento posterior de próteses totais maxilares. Sendo assim, o propósito desse trabalho foi avaliar a movimentação dentária que ocorre durante o processamento de próteses totais maxilares com três diferentes espessuras de base, frente a dois métodos de inclusão e submetidas à polimerização por microondas. Quarenta e duas (42) amostras foram aleatoriamente divididas em 6 grupos de 7 amostras cada, respeitando, evidentemente, a espessura da base (1,25 mm - 2,50 mm - 3,75 mm) e o tipo de revestimento em mufla (silicone e gesso pedra). Pontos foram demarcados sobre os dentes artificiais para permitir a mensuração das R ee ssum o amostras através do software AutoCad. A diferença das médias dos segmentos entre o modelo encerado e demuflado de cada grupo foi submetida à analise de variância (ANOVA) e teste de Tukey. De acordo com os resultados obtidos pode-se concluir que: todas as técnicas de processamento juntamente com as diferentes espessuras de base de prótese total avaliadas apresentaram alteração na posição dos dentes artificiais após o processamento. A técnica de inclusão com barreira de silicone foi a que apresentou as maiores alterações dimensionais, independentemente da espessura. Na análise dos segmentos, houve uma maior alteração dos segmentos A/B/C (Triângulo maior) com relação aos segmentos D/E/F (Triângulo menor). Independente do tipo de inclusão, não houve diferença estatística entre as espessuras das bases (p<0,059), entretanto, analisando o comportamento de alteração, as prótese totais com bases mais finas apresentaram maior... .The existent relationship between the methods of processing of the acrylic resins and the thickness of dentures bases resin, as well as the association with the size and form of the maxillary arch, it has been a subject quite discussed with regard to possible alterations in the teeth positioning and maxillary complete denture postdamming. So that, the aim of the study was to evaluate the dental movement that it happens during the processing of maxillary complete dentures with three base thickness different, front of two inclusion methods and submitted to the microwaves polymerization. Forty two (42) samples were randomly divided in 6 groups of 7 samples each, respecting, evidently, the base thickness (1,25 mm - 2,50 mm - 3,75 mm) and the type in flask investment (silicone and plaster stone). Points were demarcated on the artificial teeth to allow the measurement of the samples through the AutoCad software. The averages difference of the segments between the Ab ss tt rr a cc tt waxed model and deflasked of each group was submitted to it analysis of variance (ANOVA á=0,05) and Tukey test. In agreement with the obtained results it can be conclusion that: all the processing techniques together with the different thickness of complete denture base evaluated, presented alteration in the artificial teeth positionig after the processing. The silicone flasking technique was that presented the largest dimensional alterations, independently of the thickness. In the segments analysis, there was a larger alteration of the segments A/B/C (larger Triangle) regarding the segments D/E/F (smaller Triangle). Independent of the flasking type, there was not difference statistics among the thickness of the bases (p <0,059), however, analyzing the alteration behavior, thinner bases presented larger movement in the position of the artificial teeth than thicken base that complete denture them. The completed... (Complete abstract, click electronic address below)

Protocolo para tratamento de diastemas com laminados de porcelana: descrição de caso clínico

A percepção e o alcance da excelência estética traduzem-se especialmente em saber interpretar e satisfazer os anseios dos pacientes, empregando-se para isso todo o conhecimento disponível na literatura científica. No tratamento com laminados cerâmicos, a ciência fornece parâmetros para nos guiar com relação a um correto diagnóstico, planejamento seguro, técnica adequada e material mais indicado; porém, a subjetividade estética pode estar escondida nas entrelinhas da ciência. Contudo, o objetivo deste artigo é descrever um protocolo para fechamento de múltiplos diastemas, salientando a técnica empregada, bem como o material cerâmico utilizado e suas peculiaridades, implícitas dentro de um contexto estético específico

Optical Impression Systems for CAD-CAM Restorations

Computer-aided design/computer-aided manufacturing images can be taken through either direct or indirect imaging. For the indirect systems, the digitalization is obtained from the impression material or cast, and for the direct ones the image is taken directly from the mouth using intraoral scanners.The direct acquisition systems have been constantly improved because these are less invasive, quicker, and more precise than the conventional method. Besides, the digital images can be easily stored for a long time. Therefore, the aim of this paper was to describe and discuss based on the literature the main direct image acquisition systems available on the market: CEREC Bluecam (Sirona), Lava C.O.S. System (3M ESPE), iTero System (Cadent/Straumann), and E4D System (D4D Technologies)

A modified method of immediate occlusal loading using a reinforced framework denture: A case report

The technique presented in this article presents a protocol for treatment that reduces the time required for the fabrication and placement of an implant supported prosthesis. It also offers improved patient comfort at a lower cost when compared to conventional technology