Resin push-out bonding strength to root canal dentin: effect of the irrigation solution application prior to post cementation / Resistência de união ao push-out entre resina e dentina radicular: efeito utilização da solução irrigadora antes da cimentação do pino

Objective: To evaluate the effect of different irrigation solutions prior to post cementation on the resin bonding to bovine root dentine. Material and Methods: 60 bovine roots (16 mm) were prepared to 12 mm with specific drill of a double-tapered fiber post system, included in PMMA, and divided into 6 groups, considering the irrigation solutions (IS) prior to cementation: Gr1- saline solution (control), Gr2- NaOCl 0.5 %, Gr3- NaOCl 1 %, Gr4- NaOCl 2.5 %, Gr5- NaOCl 5 %, Gr6- Chlorexidine 2 % (solution). The root canals were irrigated with IS 20 ml during 10 min. Then they were rinsed with 20 ml of distilled water and dried with paper points. One fiber post was molded with polyvinylsiloxane and 60 posts made of resin cement (PRC) were obtained moments before the cementation. The root canal dentin was etched with H2PO3 37 %/15 s + washing/drying, a multi-bottle etch&rinse adhesive system was applied and the PRC were resin luted with dual resin cement (DuolinkTM, Bisco). Each specimen was cut into 4 slices of ±1.8mm in thickness and submitted to push-out test (1 mm/min). Results: ANOVA showed that bond strength was significantly affected by IS (P < 0.0001). The highest bond strengths (MPa) were those for the groups 4 (3.51 ± 1.52) and 5 (3.0 ± 1.16). The groups 1 (0.70 ± 0.30), 2 (0.80 ± 0.24), 3 (1.26 ± 0.57) and 6 (0.90 ± 0.41) were statistically similar to each other. Conclusion: The resin bonding to the root dentine was higher when higher concentrations of hypochlorite solutions were used. (AU)

Objetivo: Avaliar o efeito de diferentes soluções de irrigação antes da cimentação do pino na resistência de união da resina à dentina radicular bovina. Material e Métodos: Foram preparadas 60 raízes bovinas (16 mm) a 12 mm com broca específica de um sistema de pino de fibra com dupla conicidade, incluídas no PMMA, e divididas em 6 grupos, considerando as soluções irrigadoras (IS) antes da cimentação: Gr1-Solução salina (controle), Gr2-NaOCl 0,5 %, Gr3-NaOCl 1 %, Gr4-NaOCl 2,5 %, Gr5-NaOCl 5 %, Gr6-Clorexidina 2 % (solução). Os canais radiculares foram irrigados com 20 ml de IS durante 10 min. Depois, foram lavados com 20 ml de água destilada e secos com pontas de papel. Um pino de fibra foi moldado com polivinilsiloxano e 60 pinos de cimento resinoso (PRC) foram obtidos momentos antes da cimentação. A dentina radicular foi condicionada com H2PO3 37 %/15 s + lavagem/ secagem, aplicou-se o sistema de adesivo e o PRC foi cimentado com cimento resinoso dual (DuolinkTM, Bisco). Cada amostra foi cortada em 4 fatias de ± 1,8 mm de espessura e submetida a teste push-out (1 mm/ min). Resultados: ANOVA mostrou que a força de união foi significativamente afetada pelo IS (P< 0,0001). As maiores resistências de união (MPa) foram para os grupos 4 (3,51 ± 1,52) e 5 (3,0 ± 1,16). Os grupos 1 (0,70 ± 0,30), 2 (0,80 ± 0,24), 3 (1,26 ± 0,57) e 6 (0,90 ± 0,41) foram estatisticamente semelhantes entre si. Conclusão: A resistência de união da resina à dentina radicular foi maior quando foram utilizadas concentrações maiores de soluções de hipoclorito. (AU)

Effect of air-abrasion regimens and fine diamond bur grinding on flexural strength, Weibull modulus and phase transformation of zirconium dioxide.

PURPOSE: This study evaluated the effect of air abrasion and polishing regimens on the flexural strength of yttrium stabilized polycrystalline tetragonal zirconia (Y-TZP). METHODS: From Y-TZP blocks (InCeram 2000 YZ Cubes; Vita Zahnfabrik, Bad Säckingen, Germany) 120 bars (25 mm × 4 mm × 1.2 mm) were obtained according to ISO 6872:2008 and randomly divided into 4 groups: Group C: (control) without surface treatment (n = 30); Group APA: Air abrasion with aluminum oxide (44 µm) (n = 30); Group SC: Silica-coating (CoJet, 30 µm) (n = 30); Group FD: Fine diamond bur (n = 30). Subsequently, all specimens were subjected to 4-point bending test (in distilled water at 37 °C) in a universal testing machine (EMIC DL 1000; São José dos Pinhais, Paraná, Brazil); cross-head speed: 0.5 mm/min). The characteristic strength (σ0) of each specimen was obtained from the flexural strength test and evaluated using Weibull analysis. X-ray diffraction analysis was utilized to quantity the monoclinic phase. The surface topography of specimens was analyzed using 3D optical profilometer and scanning electron microscopy (SEM) after surface conditioning methods. The flexural strength data (σ4p) were statistically analyzed by 1-way ANOVA, Tukey test (α = 0.05) and Weibull (m = modulus, σ0 = characteristic strength) were calculated. RESULTS: The mean ± standard deviations (MPa) of the groups were as follows: C: 1196.2 ± 284.2a; APA: 1369.7 ± 272.3a; SC: 1207.1 ± 229.7a and FD: 874.4 ± 365.4b. The values (m) and (σ0) were as follows: C: 4.5 and 1308.12; APA: 5.9 and 1477.88; SC: 6.0 and 1300.28; and FD: 2.6 and 985.901, respectively. CONCLUSIONS: Air particle abrasion with neither silica nor alumina showed significant difference compared to the control group but grinding with fine diamond bur impaired the flexural strength of the zirconia tested.

Analysis of bond strength by pull out test on fiber glass posts cemented in different lengths.

BACKGROUND: The aim of this study was to evaluate, by means of pull-out test, the bond strength of fiberglass posts when cemented with different lengths in endodontically treated teeth. MATERIALS AND METHODS: Sixty single-rooted bovine roots were cut in the cementoenamel junction with 21 mm length. They were endodontically treated and randomly divided into three groups (n = 20). Group 1 - Preparation of 2/3 of the remaining roots; Group 2 - Preparation of ½ of the remaining roots and Group 3 - Preparation of » of remaining roots. For all groups it were used posts n = 3 (Exacto, Angelus, Brazil), and cemented with self-etching resin cement (RelyXU200). After cementing posts, the samples were thermocycled (10.000 cycles/5°C and 55°C). The pull-out test was performed on a universal testing machine (EMIC - DL500) and the values obtained were statistically analyzed by analysis of variance (one-factor ANOVA) and multiple comparison test of Tukey, with level of significance of 5%. RESULTS: The mean values ± standard deviation in Newtons (N) were: Group 1 = 120.5 (±42.8) A, Group 2 = 103.1 (±31.2) AB, Group 3 = 41.2 (±22.4) C, P < 0.005. CONCLUSION: The preparation of ½ of remaining root appears to be a viable alternative when 2/3 of the preparation of the remaining root is not possible, but more results are needed for clinical validation.

Effects of cement-curing mode and light-curing unit on the bond durability of ceramic cemented to dentin

The aim of this study was to evaluate the effects of different light-curing units and resin cement curing types on the bond durability of a feldspathic ceramic bonded to dentin. The crowns of 40 human molars were sectioned, exposing the dentin. Forty ceramic blocks of VITA VM7 were produced according to the manufacturer's recommendations. The ceramic surface was etched with 10% hydrofluoric acid / 60s and silanized. The dentin was treated with 37% phosphoric acid / 15s, and the adhesive was applied. The ceramic blocks were divided and cemented to dentin according to resin cement / RC curing type (dual- and photo-cured), light-curing unit (halogen light / QTH and LED), and storage conditions (dry and storage / 150 days + 12,000 cycles / thermocycling). All blocks were stored in distilled water (37°C / 24h) and sectioned (n = 10): G1 - QTH + RC Photo, G2 - QTH + RC Dual, G3 - LED + RC Photo, G4 - LED + RC Dual. Groups G5, G6, G7, and G8 were obtained exactly as G1 through G4, respectively, and then stored and thermocycled. Microtensile bond strength tests were performed (EMIC), and data were statistically analyzed by ANOVA and Tukey's test (5%). The bond strength values (MPa) were: G1 - 12.95 (6.40)ab; G2 - 12.02 (4.59)ab; G3 - 13.09 (5.62)ab; G4 - 15.96 (6.32)a; G5 - 6.22 (5.90)c; G6 - 9.48 (5.99)bc; G7 - 12.78 (11.30)ab; and G8 - 8.34 (5.98)bc. The same superscript letters indicate no significant differences. Different light-curing units affected the bond strength between ceramic cemented to dentin when the photo-cured cement was used, and only after aging (LED > QTH). There was no difference between the effects of dual- and photo-cured resin-luting agents on the microtensile bond strength of the cement used in this study.

Effects of cement-curing mode and light-curing unit on the bond durability of ceramic cemented to dentin.

The aim of this study was to evaluate the effects of different light-curing units and resin cement curing types on the bond durability of a feldspathic ceramic bonded to dentin. The crowns of 40 human molars were sectioned, exposing the dentin. Forty ceramic blocks of VITA VM7 were produced according to the manufacturer's recommendations. The ceramic surface was etched with 10% hydrofluoric acid / 60s and silanized. The dentin was treated with 37% phosphoric acid / 15s, and the adhesive was applied. The ceramic blocks were divided and cemented to dentin according to resin cement / RC curing type (dual- and photo-cured), light-curing unit (halogen light / QTH and LED), and storage conditions (dry and storage / 150 days + 12,000 cycles / thermocycling). All blocks were stored in distilled water (37°C / 24h) and sectioned (n = 10): G1 - QTH + RC Photo, G2 - QTH + RC Dual, G3 - LED + RC Photo, G4 - LED + RC Dual. Groups G5, G6, G7, and G8 were obtained exactly as G1 through G4, respectively, and then stored and thermocycled. Microtensile bond strength tests were performed (EMIC), and data were statistically analyzed by ANOVA and Tukey's test (5%). The bond strength values (MPa) were: G1 - 12.95 (6.40)ab; G2 - 12.02 (4.59)ab; G3 - 13.09 (5.62)ab; G4 - 15.96 (6.32)a; G5 - 6.22 (5.90)c; G6 - 9.48 (5.99)bc; G7 - 12.78 (11.30)ab; and G8 - 8.34 (5.98)bc. The same superscript letters indicate no significant differences. Different light-curing units affected the bond strength between ceramic cemented to dentin when the photo-cured cement was used, and only after aging (LED > QTH). There was no difference between the effects of dual- and photo-cured resin-luting agents on the microtensile bond strength of the cement used in this study.

Avaliação da adaptação de barras metálicas confeccionadas por técnica de moldeira aberta com união dos transferentes em diferentes resinas acrílicas / Evaluation of the precision of polyers utilized on square transfer copings splinted in implantology

A proposta deste estudo foi avaliar a adaptação de barras metálicas confeccionadas por técnica de moldeira aberta com união dos transferentes em diferentes resinas acrílicas. Foi utilizada uma mandíbula acrílica (modelo-mestre) com três implantes (Neodent/4.1HE) simetricamente posicionados com os respectivos minipilares cônicos. Sobre os minipilares foram posicionados transferentes de moldeira aberta, os quais foram unidos com fio dental e com os seguintes materiais: G1: resina bisacrílica autopolimerizável Structur 2 SC (VOCO GMBH, Alemanha); G2: resina acrílica Pattern (GC América Inc., Alsip, IL); G3: resina acrílica Duralay (Reliance Dental MFG Company,USA); G4: resina acrílica Dencrilay Speed (Dencril – Brasil); G5: resina acrílica JET (Artigos Odontológicos Clássico LTDA, Brasil). Foram realizadas 10 esplintagens por grupo (n=10) e obtidos corpos-de-prova (cp) em gesso especial tipo IV melhorado. A barra, previamente confeccionada sobre o modelo mestre através do sistema de barra cimentada e sem soldas, foi adaptada sobre os análogos e realizadas 18 leituras por cp. As análises de desadaptação (µm) foram realizadas em microscópio óptico (Mitutoyo TM-500) com aumento de 30x. Os resultados obtidos foram analisados por meio do teste de ANOVA 1-fator (a=1%) e Teste de Múltipla Comparação de Tukey. Valores de média e desvio-padrão foram os seguintes: G1 23,945±5,53a; G2 – 19,49±6,43a; G3 – 16,50±0,86a; G4 – 41,33±24,82a e G5 - 264,12±141,71b. Conclui-se que os grupos G1, G2, G3 E G4 apresentaram melhor adaptação da barra metálica sobre implantes

Análise da inter-relação entre estética periodontal e dentária / Analysis of interrelation between periodontal and dental esthetic

O objetivo do presente trabalho foi comparar a presença ou ausência de harmonia do sorriso entre homens e mulheres, tendo os parâmetros dentários e periodontais em consideração. Para esse estudo, foram selecionados 42 voluntários, sendo 21 do sexo feminino e 21 do sexo masculino.Após a realização de tomadas fotográfcas do sorriso, dentes e gengiva, os pacientes foram avaliados de acordo com os seguintes parâmetros: 1) biótipo periodontal; 2) altura do sorriso; 3) abertura do sorriso; 4) espessura do lábio; 5) comprimento e largura da coroa dentária; 6) formato do dente; 7) posição do zênite gengival; 8) posição do ponto de contato; 9) altura da gengiva bilateral; 10) altura e largura da papila interdentária; 11) presença ou ausência de proporção áurea. Após análise estatística de cada parâmetro clínico avaliado, com o teste t, e considerando p<0,05, foi possível notar que a maioria das características analisadas nos pacientes não apresentou diferença estatisticamente signifcativa entre os grupos feminino e masculino. Além disso, pôde- -se concluir que para um resultado estético satisfatório, tanto para o paciente quanto para o profssional, é indispensável a harmonia entre os tecidos dentário e periodontal.

This aim of this study was to clinically evaluate the presence or absence of smile harmony, considering dental and periodontal parameters. For this study 42 patients were selected, 21 females and 21 males. Photographs were taken from the smile, teeth and gingiva of the patients. They were evaluated in accordance with the following parameters: 1) Periodontal biotype, 2) smile height, 3) smile opening, 4) thickness of the lip, 5) length and width of the tooth, 6) format of the tooth, 7) position of the gingival zenith, 8) position of the contact point; 9) bilateral height of gingiva; 10) height and width of the interdental papilla, 11) presence or absence of golden proportion. After statistical analysis of each group, with the t-test and considering the p-value <0.05, it was clear that most of the variables analyzed in the patients did not show a statistically signifcant difference between female and male groups. Furthermore, for a satisfactory fnal result for both patient and professional, it is essential the harmony between the dental and periodontal tissues.

Marginal and internal discrepancies related to margin design of ceramic crowns fabricated by a CAD/CAM system.

PURPOSE: The aim of this study was to evaluate the marginal discrepancy (MD) and internal discrepancy (ID) of ceramic crowns manufactured by a CAD/CAM system, having different finish lines. The hypotheses tested were that the finish line type would not influence the MD or ID of the crowns, and ID would not change in different regions. MATERIALS AND METHODS: Three aluminum master dies (height: 5.5 mm, Ø: 7.5 mm, conicity: 6°) with different finish lines (TC: tilted chamfer; LC: large chamfer; RS: rounded shoulder) were manufactured. Ten impressions were made from each master die using a modified parallelometer. Impressions were poured in type IV dental stone, and 30 ceramic crowns (IPS Empress CAD, Ivoclar) were subsequently milled. The crowns were fixed on their respective metallic die using a metallic fixation device. The distance between the external edges of the crown to the edge of the cervical preparation was performed at 50 points on the respective metallic die (MD analysis). With the replica technique, the ID values of each crown were further evaluated at 12 points equidistant to each other in three regions: radius (R), axial (A), and occlusal (Occl). The measurements were performed using an optical microscope (250×). The data (µm) were analyzed using ANOVA and Tukey's test (5%). RESULTS: The RS group (28.24 ± 11.42 µm) showed significantly lower MD values (p= 0.001) than those of TC (99.92 ± 18.32 µm) and LC (64.71 ± 25.64 µm) groups, both of which also differed statistically from one another. The ID results demonstrated significantly lower values in the LC group (183.01 ± 62.82 µm) (p= 0.0014) than those of TC (216.26 ± 83.23 µm) and RS (219.12 ± 87.24 µm) groups. ID results of TC and RS were not significantly different. Additionally, the ID results showed significant differences among the regions (p= 0.0001). The null hypotheses were rejected. CONCLUSION: The RS finish line produced MD values significantly lower than tilted and large chamfer, but large chamfer presented the lowest internal discrepancy values. Independent of the finish line type, internal discrepancy was the lowest in the axial region followed by radius and occlusal regions.

The influence of cutting speed and cutting initiation location in specimen preparation for the microtensile bond strength test.

PURPOSE: This study evaluated the effect of cutting initiation location and cutting speed on the bond strength between resin cement and feldspathic ceramic. MATERIALS AND METHODS: Thirty-six blocks (6.4 x 6.4 x 4.8 mm) of ceramic (Vita VM7) were produced. The ceramic surfaces were etched with 10% hydrofluoric acid gel for 60 s and then silanized. Each ceramic block was placed in a silicon mold with the treated surface exposed. A resin cement (Variolink II) was injected into the mold over the treated surface and polymerized. The resin cement-ceramic blocks were divided into two groups according to experimental conditions: a) cutting initiation location - resin cement, ceramic and interface; and b) cutting speed - 10,000, 15,000, and 20,000 rpm. The specimens were sectioned to achieve non-trimmed bar specimens. The microtensile test was performed in a universal testing machine (1 mm/min). The failure modes were examined using an optical light microscope and SEM. Bond strength results were analyzed using one-way ANOVA and Tukey's test (α = 0.05). RESULTS: Significant influences of cutting speed and initiation location on bond strength (p < 0.05) were observed. The highest mean was achieved for specimens cut at 15,000 rpm at the interface (15.12 ± 5.36 MPa). The lowest means were obtained for specimens cut at the highest cutting speed in resin cement (8.50 ± 3.27 MPa), and cut at the lowest cutting speed in ceramic (8.60 ± 2.65 MPa). All groups showed mainly mixed failure (75% to 100%). CONCLUSION: The cutting speed and initiation location are important factors that should be considered during specimen preparation for microtensile bond strength testing, as both may influence the bond strength results.

Avaliação dos níveis de proteína C-reativa em pacientes periodontais / Evaluation of c-reactive protein levels in pacients with periodontal disease

Justificativa: estudos epidemiológicos sugerem aumento de evidências de que infecções crônicas, como periodontite, com seu mecanismo inflamatório, desempenham papéis importantes na formação de placa aterosclerótica e doença cardiovascular, principalmente pelo aumento dos níveis de proteína C-reatlva (PCR). Desta forma, o objetivo do presente estudo foi avaliar se a presença de periodontite crônica e seu subsequente tratamento podem alterar os níveis séricos de PCR. Métodos: foram selecionados 15 pacientes saudáveis do grupo controle e 15 pacientes com doença periodontal que foram submetidos a exames de proteína C-reativa ultrassensível, imediatamente antes do início e após o tratamento periodontal não cirúrgico de raspagem e alisamento radiculares. A determinação quantitativa da PCR ultrassensível foi realizada no soro humano através do método de turbidimetria. Resultados: o valor médio dos níveis de PCR encontrados nos indivíduos foi de 0,57 mg/L para o grupo controle, 2,45 mg/L e 0,44 mg/L para o grupo teste antes e após o tratamento periodontal, respectivamente. Conclusão: os resultados encontrados indicam que a doença periodontal promove aumento nos níveis de PCR e que o seu tratamento pode causar diminuição dessa proteína, podendo ser um meio de diminuir o risco para doença cardiovascular.

Influência do tratamento de superfície na resistência à flexão e na transformação de fase de zircônia tetragonal policristalina estabilizada por óxido de ítrio (y-tzp) / Influence of surface treatment on flexural strength and on phase transformation of yttrium stabilized policristaline tetragonal zirconia (Y-TZP)

Neste estudo avaliou-se a influência do tratamento de superfície para cimentação na resistência à flexão de 4 pontos de zircônia tetragonal poli cristalina estabilizada por óxido de ítrio (Y-TZP). Por meio de blocos pré-sinterizados de Y-TZP (InCeram 2000 YZ Cubes, Vita Zahnfabrik) foram confeccionadas 120 barras (20mm x 4mm x 1,2mm) de acordo com a norma ISO 6872:2008 e aleatoriamente divididas em 4 grupos: Grupo 1: silicatização (Cojet 30 μm) (n=29); Grupo 2: jateamento com óxido de alumínio (44 μm) (n=29); Grupo 3: ponta diamantada de granulação extra-fina (30 μm) (n=27); Grupo 4: (controle) sem tratamento de superfície (n=29). Em seguida, todas as amostras foram submetidas ao ensaio de flexão de 4 pontos (imersos em água destilada à 370C) em máquina de ensaio universal com velocidade de 0,5 mm/min até o rompimento das mesmas. A análise de difração de raios-X foi utilizada para determinar a transformação de fase. A microestrutura da Y-TZP e o padrão de tratamento de superfície foram analisados por meio de perfilometria óptica e microscopia eletrônica de varredura. Os dados de resistência à flexão foram estatisticamente analisados por meio de ANOVA 1-fator, teste de Tukey HSD (α=0,05) e Weibull (m=módulo; σ0=resistência característica). As médias±desvio-padrão (MPa) foram os seguintes: G1:1207,1±229,7a; G2: 1369,7±272,3a; G3: 874,4±365,4b e G4: 1196,2±284,2a. Os valores de (m) e (σ0) foram: G1: 6,0 e 1300,28; G2: 5,9 e 1477,88; G3: 2,6 e 985,901 e G4: 4,5 e 1308,12. Concluiu-se que a utilização de pontas diamantadas de granulação extra-fina deve ser evitada nos procedimentos prévios à cimentação resinosa de Y-TZP.

This study evaluated the influence of surface treatment on 4-point bending test of yttrium stabilized poli cristaline tetragonal zirconia (Y-TZP). From Y-TZP blocks (InCeram 2000 YZ Cubes, Vita Zahnfabrik) were obtained 120 bars (20mm×4mm×1.2mm) according to norm ISO 6872:2008 and randomly divided in 4 groups: Group 1: silicatization (Cojet 30 μm) (n=29); Group 2: sandblasting with aluminium oxide (44 μm) (n=29); Group 3: fine coarse diamond bur (30 μm) (n=27); Group 4: (control) without surface treatment (n=29). As follow, all samples were submitted to the 4-point bending test (immersed in distilled water at 370C) in an universal testing machine with cross-head speed of 0.5 mm/min until the rupture of the samples. X-ray diffraction analysis was utilized to quantify the monoclinic phase. The microstructure of Y-TZP and pattern of surface treatment were analyzed by optic profilometer and scanning electron microscopy. The data of flexural strength (σ4p) were statistically analyzed by 1-factor ANOVA, Tukey HSD (α= 0.05) and Weibull (m= modulus, σ0 = characteristic strength). The mean±standard deviation (MPa) were the following: G1:1207.1±229.7a; G2: 1369.7±272.3a; G3: 874.4±365.4b and G4: 1196.2±284.2a. The values of (m) and (σ0) were: G1: 6.0 and 1300.28; G2: 5.9 and 1477.88; G3: 2.6 and 985.901 and G4: 4.5 and 1308.12. It was concluded that silicatization and sandblasting increased the flexural strength of Y-TZP, diminished the roughness of surface and present higher reliability for cementation of Y-TZP restorations.

Intrapulpal temperature variation during bleaching with various activation mechanisms.

OBJECTIVES: The aim of this study was to evaluate the intrapulpal temperature variation after bleaching treatment with 35% hydrogen peroxide using different sources of activation. MATERIAL AND METHODS: Twenty-four human teeth were sectioned in the mesiodistal direction providing 48 specimens, and were divided into 4 groups (n=12): (G1) Control - Bleaching gel without light activation, (G2) Bleaching gel + halogen light, (G3) Bleaching gel + LED, (G4) Bleaching gel + Nd:YAG Laser. The temperatures were recorded using a digital thermometer at 4 time points: before bleaching gel application, 1 min after bleaching gel application, during activation of the bleaching gel, and after the bleaching agent turned from a dark-red into a clear gel. Data were analyzed statistically by the Dunnet's test, ANOVA and Tukey's test (a=0.05). RESULTS: The mean intrapulpal temperature values ( degrees C) in the groups were: G1: 0.617 +/- 0.41; G2: 1.800 +/- 0.68; G3: 0.975 +/- 0.51; and G4: 4.325 +/- 1.09. The mean maximum temperature variation (MTV) values were: 1.5 degrees C (G1), 2.9 degrees C (G2), 1.7 degrees C (G3) and 6.9 degrees C (G4). When comparing the experimental groups to the control group, G3 was not statistically different from G1 (p>0.05), but G2 and G4 presented significantly higher (p<0.05) intrapulpal temperatures and MTV. The three experimental groups differed significantly (p<0.05) from each other. CONCLUSIONS: The Nd:YAG laser was the activation method that presented the highest values of intrapulpal temperature variation when compared with LED and halogen light. The group activated by LED light presented the lowest values of temperature variation, which were similar to that of the control group.

Intrapulpal temperature variation during bleaching with various activation mechanisms

OBJECTIVES: The aim of this study was to evaluate the intrapulpal temperature variation after bleaching treatment with 35 percent hydrogen peroxide using different sources of activation. MATERIAL AND METHODS: Twenty-four human teeth were sectioned in the mesiodistal direction providing 48 specimens, and were divided into 4 groups (n=12): (G1) Control - Bleaching gel without light activation, (G2) Bleaching gel + halogen light, (G3) Bleaching gel + LED, (G4) Bleaching gel + Nd:YAG Laser. The temperatures were recorded using a digital thermometer at 4 time points: before bleaching gel application, 1 min after bleaching gel application, during activation of the bleaching gel, and after the bleaching agent turned from a dark-red into a clear gel. Data were analyzed statistically by the Dunnet's test, ANOVA and Tukey's test (a=0.05). RESULTS: The mean intrapulpal temperature values (ºC) in the groups were: G1: 0.617 ± 0.41; G2: 1.800 ± 0.68; G3: 0.975 ± 0.51; and G4: 4.325 ± 1.09. The mean maximum temperature variation (MTV) values were: 1.5ºC (G1), 2.9ºC (G2), 1.7ºC (G3) and 6.9ºC (G4). When comparing the experimental groups to the control group, G3 was not statistically different from G1 (p>0.05), but G2 and G4 presented significantly higher (p<0.05) intrapulpal temperatures and MTV. The three experimental groups differed significantly (p<0.05) from each other. CONCLUSIONS: The Nd:YAG laser was the activation method that presented the highest values of intrapulpal temperature variation when compared with LED and halogen light. The group activated by LED light presented the lowest values of temperature variation, which were similar to that of the control group.

Avaliação da dureza Vickers de resinas compostas de uso direto e indireto / Evaluation of Vickers hardness of direct and indirect composite resins

Objetivo: Este estudo propôs avaliar a microdureza de diferentes resinas compostas de uso direto (rcd) e indireto (rci). Materiais e Métodos: Com o auxílio de uma matriz metálica (diâmetro: 5,0mm; espessura: 2,0mm) foram confeccionadas 70 amostras, sendo (n=10) três resinas de uso direto: Gr1- Z250(3M ESPE/EUA), Gr2- W3D(Wilcos/Brasil) e Gr3- Esthetic X(Dentisply/EUA); e quatro de uso indireto: Gr4- Resilab Master (Wilcos/Brasil), Gr5- Vita VM LC (Vita Zahnfabrik/Alemanha), Gr6- Vita Zeta (Vita Zahnfabrik/Alemanha) e Gr7- Sinfony (3M ESPE/EUA). As amostras das rcd foram confeccionadas utilizando a técnica incremental, onde cada incremento de resina foi fotopolimerizado durante 40 segundos. Já as amostras da rci foram polimerizadas segundo recomendações dos fabricantes. Todos os espécimes foram armazenados em água destilada a 37ºC durante 24 horas. O teste de microdureza foi realizado em microdurômetro digital (Future-Tech,Modelo FM 700), com carga de 50 kgf por 15 segundos. Os dados obtidos (Kgf/mm2) foram analisados utilizando o teste não paramétrico de Kruskal-Wallis e o de comparação múltipla de Dunn (p<0.05). Resultados: As medidas resumo-numéricas de microdureza obtidas foram (mediana; média ± desvio padrão): Gr1 (100,12; 101,07± 5,99 Kgf/mm2), Gr2 (83,55; 84,20± 5,07 Kgf/mm2), Gr3 (73,98; 73,95± 6,55 Kgf/mm2), Gr4 (52,50; 52,54± 5,9 Kgf/mm2), Gr5 (33,25; 34,36± 2,29 Kgf/mm2), Gr6 (29,60; 29.68± 1.52 Kgf/mm2), Gr7 (25,39; 25.13± 2.08 Kgf/mm2). Verificou-se que os valores de microdureza das rcd analisadas não diferiram estatisticamente entre si (p<0,05). O mesmo não se pode estabelecer para as resinas indiretas, pois a Sinfony diferiu da Resilab (p<0,05). Conclusão: Baseado nos resultados pôde-se concluir que apenas a resina composta direta Z250 apresentou valores de microdureza Vickers superior às demais resinas indiretas.

Estabilidade de Cor de uma Resina Composta Indireta / Color Stability of an Indirect Composite Resin

A cor das resinas compostas indiretas é um dos mais importantes fatores no sucesso do tratamento protético. Com este material a estabilidade de cor é aspecto preponderante na longevidade deste trabalho. A proposta deste estudo foi avaliar a estabilidade de cor de resina composta indireta (Resilab Master, Wilcos – Brasil) através de um colorímetro digital. Foram confeccionados 32 corpos-de-prova (CP). Realizou-se o registro inicial da cor de cada CP, através de um colorímetro digital, que foram distribuídos em 4 grupos (n=8) e imersos em diferentes soluções. Grupo 1 (controle): água destilada/estufa; Grupo 2: água destilada/termociclagem; Grupo 3 : suco de laranja/termociclagem e Grupo 4: café/termociclagem. Após termociclagem e imersão em estufa (tempo total aproximado de 60 horas), as amostras foram enxaguadas e o registro final da cor foi obtido. Os dados foram submetidos à análise estatística (Teste de Dunnet – p<0,005). Os resultados mostraram que os valores de ΔE (diferença de cor) e desvio padrão dos grupos foram: G1: 2,35±0,84; G2: 2,97±1,21; G3: 8,33±5,87; G4: 22,38±5,33. Foi observado que os grupos 3 e 4 diferiram estatisticamente do grupo 1, exceto o grupo 2 que não foi estatisticamente significante. Baseado nos resultados, conclui-se que a termociclagem contribui para uma alteração de cor da resina composta indireta e a solução de café mancha mais do que o suco de laranja.

Remoção do parafuso de fixação fraturado do implante: relato de caso / Removal of fractured implant abutment screw: a case report

Apesar da reabilitação de pacientes parcial e totalmente edêntulos com implantes osseointegrados ser clinicamente aceitável na Odontologia moderna, muitas falhas ainda podem ocorrer nesse tipo de tratamento protético. Freqüentemente o afrouxamento e fratura dos parafusos de fixação e/ou retenção dos componentes dos implantes serve como um sinal de alerta, indicando que o sistema de conexões necessita de uma reavaliação. Assim, a proposta deste trabalho foi relatar a situação clínica da fratura de um parafuso de fixação e a técnica de remoção do fragmento no interior do implante.

Estágio atual das resinas compostas indiretas: uma revisão da literatura / Current perspectives of indirect composites: a literature review

O anseio dos pacientes que procuram tratamento dentário com excelência estética, bem como o desejo dos profissionais de odontologia em buscar melhores soluções protéticas, tem motivado inúmeros esforços nos últimos anos para o aperfeiçoamento tecnológico e biomecânico dos materiais restauradores. Por isso, o objetivo deste trabalho foi rever algumas propriedades das resinas compostas indiretas, abordar novidades que estão surgindo através de tecnologias, e elucidar algumas perspectivas futuras desses materiais. Concluiu-se que a tendência atual é o surgimento de um material que reúna cada vez mais as propriedades físico-mecânicas necessárias para se obter materiais restauradores de alta qualidade e estética satisfatória.

Efeito do tratamento de superfície de uma cerâmica aluminizada infiltrada de vidro sobre a resistência à microtração / Effect of surface treatment of a glass-infiltrated alumina ceramic on the microtensile bond strength

Este estudo avaliou a resistência à microtração entre um cimento resinoso e uma cerâmica submetida a três tratamentos de superfície. Foram confeccionados 12 blocos da cerâmica In-Ceram Alumina (VITA) e 12 blocos de resina composta (Clearfil APX, Kuraray) com dimensões de 6mm x 6mm x 5mm. A superfície da cerâmica foi polida com lixas d'água nº 600, 800 e 1200 sob refrigeração, e os blocos foram divididos em três grupos conforme o tratamento superficial: Grupo 1 - Jateamento com óxido de alumínio 110µm; Grupo 2 - Sistema Rocatec (3M/ESPE): jateamento com óxido de alumínio 110µm (Rocatec-pre powder) e com sílica (Rocatec-plus powder) + silano (Rocatec-Sil); Grupo 3 - Sistema CoJet (3M/ESPE): jateamento com partículas de sílica 30µm + ESPE-Sil. Os blocos cerâmicos foram cimentados aos de resina composta com o cimento resinoso Panavia F (Kuraray Co) conforme as instruções do fabricante, sob carga de 750g por 10min. As amostras foram armazenadas (água destilada/37ºC/7 dias) e seccionadas em dois eixos, x e y, com disco diamantado sob refrigeração em uma máquina de corte a fim de obter corpos-de-prova (CP) com 0,6±0,1mm² de área adesiva (n=36). Os CP foram fixados em dispositivo adaptado para o teste de microtração e tracionados (velocidade: 0,5 mm.min-1) na máquina de ensaio universal EMIC. Os resultados (MPa) foram submetidos à análise de variância e ao Teste de Tukey (p<0,05) [grupo 1 - 15,36; grupo 2 - 30,98 e grupo 3 - 31,25]. Os grupos 2 (Rocatec) e 3 (CoJet) apresentaram maior resistência adesiva que o grupo 1. Não houve diferença estatística significativa entre os grupos 2 e 3.

[Effect of surface treatment of a glass-infiltrated alumina ceramic on the microtensile bond strength]. / Efeito do tratamento de superfície de uma cerâmica aluminizada infiltrada de vidro sobre a resistência à microtração.

This study evaluated the microtensile bond strength of a resin composite to a ceramic submitted to three surface treatments. Twelve glass-infiltrated alumina ceramic blocks (In-Ceram Alumina, VITA) and twelve resin composite blocks (Clearfil APX, Kuraray) with dimensions of 6mm x 6mm x 5mm were made. The surface of the ceramic was wet-grounded with # 600, 800 and 1200-grid sandpaper, and the blocks were divided in three groups: Group 1 - sandblasting with aluminum oxide - particles 110mm (Micro-Etcher, Danville); Group 2 - Rocatec System (ESPE): Tribochemical silica coating (Rocatec pre-powder + Rocatec-Plus powder + Rocatec-Sil); Group 3 - CoJet System (3M/ESPE): silica coating (silica oxide + ESPE-Sil). The ceramic blocks were cemented to the resin composite blocks with Panavia F (Kuraray Co), following the manufacturer's instructions, under load of 750g for 10min. The samples were stored (distilled water / 7 days / 37O C) and sectioned in two axis, x and y, with diamond disk under cooling in order to obtain samples (S) with 0.6 ± 0.1mm² of adhesive area (n=36). The S were attached in adapted device for the microtensile test that was performed at an universal testing machine (EMIC), at a speed of 1mm/min. The results (MPa) were submitted to ANOVA and Tukey's test (p<0.05): G1 - 15.36; G2 - 30.98; G3 - 31.25. Groups 2 (Rocatec) and 3 (CoJet) presented larger bond strength than group 1. There was no statistical difference between group 2 and group 3.