Damping behavior of implant-supported restorations.

OBJECTIVES: The aim of the present study was to assess the shock absorbing capacity of implant-supported restorations (CAD/CAM composite resin or zirconia abutment with composite resin or porcelain crown/onlay) and a simulated natural tooth complex using the Periometer(®) . MATERIAL AND METHODS: One hundred and twenty Morse taper implants (Titamax CM 11 mm) were mounted on bone-simulating acrylic resin base and restored with CAD/CAM zirconia (60) and metal composite resin Paradigm MZ100 (60) abutments. Using CEREC3, standardized onlays (60) and crowns (60) were designed and milled in ceramic (Paradigm C) or composite resin (Paradigm MZ100) to simulate a maxillary premolar. All restorations were luted with a preheated light curing composite resin (Filtek Z100). Fifteen extracted human upper premolars were mounted with a simulated PDL and used as control group. The Periometer(®) , a new handheld percussion probe that measures the energy loss coefficient (LC) for both natural teeth and implant-supported structures, was positioned perpendicularly to the buccal surface of each restoration. Three measurements of the LC were collected for each specimen. The effect of each variable (abutment material, restoration material, and restoration design) on the LC was explored using multiple regression analysis. RESULTS: Differences in LC between the abutment material (zirconia/Paradigm MZ100), the restoration material (Paradigm C/Paradigm MZ100) and the restoration design (onlay/crown) were recorded. The average LC of zirconia and metal composite resin abutments ranged from 0.040 to 0.053 and 0.059 to 0.068, respectively. Zirconia abutments restored with composite resin restorations (LC 0.051-0.053) had the closest LC value when compared with teeth with simulated PDL (0.049). CONCLUSION: Composite resin onlays/crowns bonded to zirconia implant abutments presented similar dynamic response to load (damping behavior) when compared to teeth with a simulated PDL.

Fatigue resistance and failure mode of adhesively restored custom implant zirconia abutments.

OBJECTIVES: This study assessed the fatigue resistance and failure mode of porcelain and composite resin crowns and onlays bonded to premolar custom zirconia implant abutments. MATERIALS AND METHODS: Sixty standardized zirconia implant abutments were milled (NeoShape) according to two different restoration designs (onlay or crown). Using Cerec 3, the corresponding onlays and crowns were fabricated either in ceramic (Paradigm C) or composite resin (Paradigm MZ100), resulting in four experimental groups (n = 15). The fitting surfaces of the abutments were airborne-particle abraded and cleaned. The intaglio surfaces of the restorations were HF-etched and silanated (Paradigm C) or airborne-particle abraded and silanated (Paradigm MZ100). Following insertion of the abutments into a Morse taper implant (Titamax CM), all restorations were bonded with a zirconia primer (Z-Prime Plus), adhesive resin (Optibond FL), and a preheated light curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz) was simulated, starting with a load of 50N (5000×), followed by stages of 200N, 400N, 600N, 800N, 1000N, 1200N, and 1400N (25,000× each). Samples were loaded until fracture or to a maximum of 180,000 cycles. The four groups were compared using the life table survival analysis (Logrank test at P = 0.05). RESULTS: All composite resin onlays and crowns survived (100% survival rate), while ceramic ones fractured at an average load of 1347N and 1280N, respectively, (survival rate of 46.7% and 20%) with a significant difference in survival probability (P < 0.0001). Fractures consisted in partial or total failure of the restoration only (no abutment failure, no screw loosening). CONCLUSIONS: Composite resin onlays and crowns bonded to custom zirconia implant abutments presented a significant higher survival rate when compared to ceramic onlays and crowns.

Fatigue resistance and failure mode of CAD/CAM composite resin implant abutments restored with type III composite resin and porcelain veneers.

OBJECTIVES: This study assessed the fatigue resistance and failure mode of type III porcelain and composite resin veneers bonded to custom composite resin implant abutments. MATERIAL AND METHODS: Using the CEREC 3 machine, 28 composite resin implant abutments (Paradigm MZ100) were fabricated along with non-retentive type III veneers, milled either in ceramic Paradigm C (n=14) or in composite resin Paradigm MZ100 (n=14). The intaglio surfaces of the veneers were hydrofluoric acid etched and silanated (Paradigm C) or airborne-particle abraded and silanated (MZ100). The fitting surface of the abutments was airborne-particle abraded, cleaned, silanated and inserted into a bone level implant (10 mm, BLI RC). All veneers were luted with adhesive resin (Optibond FL) and a preheated light curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz, 30° angle) was simulated, starting with a load of 40 N, followed by stages of 80, 120, 160, 200, 240 and 280 N (20,000 cycles each). Samples were loaded until fracture or to a maximum of 140,000 cycles. Groups were compared using the life table survival analysis (Log rank test at P=0.05). Previously published data using same-design zirconia abutments were included for comparison. RESULTS: Paradigm C and MZ100 specimens fractured at an average load of 243 and 206 N (survival rate of 21% and 0%), respectively, with a significant difference in survival probability (P=0.02). Fractured specimens presented mixed failure modes and solely adhesive failures were not observed. The survival of composite resin abutments was similar to that of identical zirconia abutments from a previous study (P=0.76). CONCLUSIONS: Non-retentive porcelain veneers bonded to custom composite resin implant abutments presented a higher survival rate when compared with composite resin veneers. Survival of composite resin abutment did not differ from zirconia ones.

Fatigue resistance and failure mode of adhesively restored custom metal-composite resin premolar implant abutments.

PURPOSE: To evaluate the fatigue resistance and failure mode of composite resin and porcelain onlays and crowns bonded to premolar custom metal-composite resin premolar implant abutments. MATERIALS AND METHODS: Sixty composite resin mesostructures were fabricated with computer assistance with two preparation designs (crown vs onlay) and bonded to a metal implant abutment. Following insertion into an implant with a tapered abutment interface (Titamax CM), each metal-composite resin abutment was restored with either composite resin (Paradigm MZ100) or ceramic (Paradigm C) (n = 15) and attached with adhesive resin (Optibond FL) and a preheated light-curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz) was then simulated, starting with 5,000 cycles at a load of 50 N, followed by stages of 200, 400, 600, 800, 1,000, 1,200, and 1,400 N (25,000 cycles each). Samples were loaded until fracture or to a maximum of 180,000 cycles. The four groups were compared using life table survival analysis (log-rank test). Previously published data using zirconia abutments of the same design were included for comparison. RESULTS: Paradigm C and MZ100 specimens fractured at average loads of 1,133 N and 1,266 N, respectively. Survival rates ranged from 20% to 33.3% (ceramic crowns and onlays) to 60% (composite resin crowns and onlays) and were significantly different (pooled data for restorative material). There were no restoration failures, but there were adhesive failures at the connection between the abutment and the mesostructure. The survival of the metal-composite resin premolar abutments was inferior to that of identical zirconia abutments from a previous study (pooled data for abutment material). CONCLUSIONS: Composite resin onlays/crowns bonded to metal-composite resin premolar implant abutments presented higher survival rates than comparable ceramic onlays/crowns. Zirconia abutments outperformed the metal-composite resin premolar abutments.

Selective masking for thin indirect restorations: can the use of opaque resin affect the dentine bond strength of immediately sealed preparations?

PURPOSE: Evaluate the dentine bond strength using different methods of application of opaque resins to mask dentine discoloration. MATERIALS AND METHODS: Dentine was exposed on 21 extracted molars which were assigned to 3 groups: G1: immediate dentine sealing (IDS). G2: IDS+opaque. G3: IDS with adhesive resin mixed with opaque. After 1 week, teeth were restored and beams were fabricated for microtensile testing. Optical microscopy was used to analyse the failure mode. RESULTS: Bond strength mean values were statistically different: G1 55.20MPa>G2 45.79MPa>G3 18.96MPa. Failure modes were mostly adhesive for G1 and G3. G2 presented mostly mixed failures. CONCLUSION: The use of opaque resin to mask discoloured dentine results in a decrease of bond strength.

Effect of the activation mode of post adhesive cementation on push-out bond strength to root canal dentin.

OBJECTIVE: To evaluate the effect of the activation mode of adhesive cementation on push-out bond strength of fiber-reinforced resin posts to root canal dentin. METHOD AND MATERIALS: Forty mandibular premolars were endodontically treated and randomly divided into 4 equal groups. In groups G-1, G-2, and G-3, Single Bond (3M Espe) was applied and light polymerized for 20 seconds; in group G-4, Scotchbond Multi-Purpose Plus (3M Espe) was used as an autopolymerized adhesive. The dual-cure resin cement Rely X ARC (3M Espe) was light polymerized in G-2 and G-3 but not in G-1 and G-4. The translucent post Light-Post (Bisco) was used in G-3 and the opaque post Aestheti-Plus (Bisco) in the other groups. The roots were sectioned in 3 parts (cervical, middle, apical); each slice was submitted to the push-out test at a crosshead speed of 0.5 mm/min. Data were analyzed by analysis of variance and Tukey test (a = .05). RESULTS: Light polymerization of both the adhesive and resin cement in G-2 led to significantly higher bond strength than in G-1, where only the adhesive was light polymerized. No difference was found between G-2 (opaque post) and G-3 (translucent post). The autopolymerized adhesive showed the highest bond strength in all root regions. The middle and apical post/root regions had similar bond strength, but it was significantly lower than that in the cervical region (P <.001). CONCLUSION: Bond strength to root dentin varied as a function of the activation mode of post adhesive cementation and post/root regions.

Avaliação da resistência de união à microtração da resina composta pré-aquecida e do cimento resinoso dual na cimentação de blocos de resina de diferentes espessuras / Evaluation of microtensile bond strength of pre-heated composite resin and dual adhesive cement over resin blocks of varied thicknesses

A resina composta pré-aquecida constitui uma excelente opção de material para cimentação de restaurações adesivas. Existe dúvida, porém, quanto à capacidade de fotopolimerização do material sob restaurações indiretas, como facetas, inlays e onlays. Para este estudo, foram seccionados 32 incisivos bovinos hígidos padronizados. Todos os dentes apresentavam 12 mm de comprimento e exposição da dentina coronária, sendo divididos em quatro grupos (n=8). De acordo com a espessura do bloco de resina composta (2 mm e 4 mm) e o agente cimentante utilizado (Z100 e RelyX ARC), foram classificados em quatro grupos. Os grupos RC2 e RC4 apresentavam blocos de 2 mm e 4 mm de espessura, respectivamente, e cimentação com resina composta préaquecida; os grupos CR2 e CR4 apresentavam blocos de 2 mm e 4 mm, respectivamente, e cimentação com cimento resinoso dual. Previamente à cimentação, os blocos foram jateados com partículas de 27 µm de óxido de alumínio a uma distância de 1 cm, com angulação de 45o e 80 psi de pressão. Posteriormente, foram condicionados com ácido fosfórico a 37% e foi aplicado o adesivo, sem fotoativação. Os dentes foram jateados, condicionados e tiveram o adesivo fotoativado. A cimentação foi realizada com resina composta (Z100) pré-aquecida (54ºC) em um dispositivo elétrico (Calset), para os grupos 1 e 2, e cimento resinoso dual (RelyX ARC), para os grupos 3 e 4. A fotopolimerização ocorreu com o auxílio de uma barreira lateral de silicone, a fim de permitir que a luz alcançasse o substrato apenas por meio da superfície oclusal do bloco. Foram realizados ciclos de 40 segundos de fotoativação nas porções mesial, distal, vestibular, palatal e central da porção superior do bloco. Os espécimes foram armazenados em água destilada durante 30 dias em ambiente úmido e escuro. Cada espécime foi seccionado com o auxílio de uma máquina de corte (Isomet 1000) para obtenção de palitos de 1 mm2, que foram submetidos ao teste microtração. Os dados foram comparados pelo teste Mann-Whitney, e a comparação entre todos os grupos foi realizada pelo teste de Kruskal-Wallis. Os resultados mostraram que não houve diferença estatisticamente significante entre a resistência de união à microtração nos grupos RC2 e RC4 (p=0,105), e entre os grupos CR2 e CR4 (p=0,061). Entretanto, houve diferença estatística entre CR2 e RC4 (p=0,031). Concluiu-se que a resina composta pré-aquecida como agente cimentante é tão eficiente quanto o cimento resinoso, independentemente da espessura da restauração indireta (até 4 mm).

Regular pre-heated composite resin is an excellent material choice for bonding adhesive restorations as inlays, onlays and veneers. However, it is unclear whether light can activate the material underneath the restorations. For this study, 32 healthy incisors were selected (12 mm in length) and with the exposure of coronary dentin. The teeth were divided into 4 groups (n=8), according to the thickness of the indirect composite resin restoration and to the cement used: groups 1 and 2 (RC2, RC4) ­ blocks 2 mm and 4 mm thick cemented with pre-heated composite resin (Z100); groups 3 and 4 (CR2, CR4) ­ blocks 2 mm and 4 mm and cementing with dual resin cement (RelyX ARC). Before luting, the blocks were sandblasted with Al2O3 27 mm particles (45-degrees, 1 cm distance, 80 psi), then etched with 37% phosphoric acid, being the adhesive agent applied but not activated. Teeth were sandblasted, etched and the adhesive agent was applied and activated. The Z100 composite resin was pre-heated (540C, Calset) for groups 1 and 2, and the RelyX ARC resin cement for groups 3 and 4. A silicone barrier was made to direct light polymerization at the occlusal surface (40s cycles at the mesial, distal, buccal, palatal, and middle of the upper block region). The specimens were stored in distilled water for 30 days, being sectioned for 1 mm2 microtensile test (Isomet 1000). The Mann-Whitney and Kruskal-Wallis tests were used for data comparison. No differences were seen for microtensile values between groups RC2 and RC4 (p=0.105), and between CR2 and CR4 (p=0.061). However, a significant difference was observed between CR2 and RC4 (p=0.031). The pre-heated composite resin as a luting agent is so efficient as the resin cement regardless of the thickness of the indirect restoration (up to 4 mm).

Avaliação da satisfação de pacientes reabilitados por implantes osseointegráveis / Evaluation of patients satisfaction treated by osseointegrated implants

O objetivo deste estudo é avaliar a satisfação com o tratamento restaurador de um grupo de pacientes que receberam implantes osseointegráveis. Assim como correlacionar tais escores com as etapas cirúrgicas e/ou protéticas e com os resultados funcionais deste tratamento. Por meio de uma análise retrospectiva foram selecionados 122 pacientes tratados com implantes dentários utilizando-se protocolo de dois estágios, sendo que 43 são homens e 79 mulheres, na faixa etária entre os 22 e 74 anos. Os implantes foram instalados e restaurados com próteses fixas metalocerâmicas, metaloplásticas e coroas puras de acrílico. Num período de 12 a 72 meses após a instalação da prótese fixa, estes pacientes responderam a um questionário de 22 perguntas relativas à etapa de instalação dos implantes, segunda etapa cirúrgica, confecção e adaptação com a nova prótese, custo, qualidade mastigatória e dificuldade de mastigação, utilizando a Escala de Análise Visual (VAS). Os valores atribuídos foram transformados em escores e divididos em quatro grupos de acordo com o grau de satisfação do paciente. Os valores atribuídos às respostas foram mensurados e agrupados em escores assim divididos: (1) Totalmente insatisfeitos (de zero a 25 mm); (2) Parcialmente insatisfeitos (de 26 mm a 50 mm); (3) Parcialmente satisfeitos (de 51 mm a 75 mm); e (4) Totalmente satisfeitos (de 76 mm a 100 mm). Dos 122 pacientes analisados, 48 demonstraram não estar totalmente satisfeitos. Os motivos manifestados de algum descontentamento estavam na etapa de instalação do implantes (15); segunda etapa cirúrgica (9), dificuldades no momento de confecção ou adaptação com a nova prótese (6). Os outros motivos também manifestados de insatisfação parcial foram o custo do tratamento, a qualidade mastigatória e a dificuldade de higienização. Com relação aos pacientes avaliados neste estudo, o tratamento com implantes osseointegráveis e próteses fixas sobreimplantes apresentaram um grau elevado de satisfação...

The purpose of the present study was to evaluate the degree of satisfaction of a group of patients treated by osseointegrated implants. So that, correlate the scores with the surgical and/or prosthetic procedures, and with the functional results. One hundred twenty two patients treated by dental implants in a two stage protocol were selected for the study. All the implants were placed and restored by fixed prostheses and investigated during a period of 12 to 72 months. The patients answered to 22 questions regarding to the treatment by mean of a visual analog scale(VAS), 12 to 72 months after the prostheses confection. The values were transformed in scores and divided into 4 groups in accordance with the patient satisfaction degree. Among the 122 analyzed patients, 48 seem to be not completely satisfaction. From this 48 patients group, 15 expressed discomfort during placing the implants, 9 during the reopening and 6 during the new prostheses confection period. Another points cited as partial satisfaction results were the treatment coast, masticator quality and hygiene difficult. Among the patients evaluated in the present study, dental implants and fixed prostheses presented high degree of general satisfaction with the treatment.