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To evaluate the influence of photodynamic therapy (PDT), different final irrigants, and ultrasonic activation (US) on the bond strength of glass fiber posts (GFP) to root dentin.One hundred twenty bovine roots were divided into 12 groups according to PDT application, the type of final endodontic irrigant, and US. The samples were divided into 12 groups (n = 10): G1-DW(distilled water); G2-DW+US; G3-17% EDTA; G4-17% EDTA+US; G5-17% GA (glycolic acid); G6-17% GA+US; G7-PDT+DW; G8-PDT+DW+US; G9-PDT+17% EDTA; G10-PDT+17% EDTA+US; G11-PDT+17% GA; G12-PDT+17% GA+US. After cementing the glass fiber posts with resin cement, roots were sectioned into 2-mm-thick slices. One slice from the cervical third and another from the middle third were used for the push out test (PO), and the other two for the diametral compression test (DC). Thus, 10 samples were obtained per third for each mechanical test (n = 10). Kruskal-Wallis and Student-Newman-Keuls tests were used to analyze PO and DC data, and Pearson's correlation test was used to verify the relationship between the variables. Failure patterns were analyzed with chi-square test.Significant differences were found in the PO test among the experimental groups (p 0.001; power=1.00). PDT improved bond strength when using EDTA. PDT and US increased bond strength when using GA. Favorable failure patterns occurred more frequently in Group GA+US. There was no correlation between data obtained with PO and DC tests (r = 0.112; p = 0.729).PDT provided the highest bond strength values of GFP to root dentin when associated with GA and US or when associated only with EDTA.

To investigate the optimal combination of factors (finish line, scanning, and ceramic processing) to achieve the best values of both adaptation and fracture load of lithium disilicate (LD) crowns.Abutment preparations, chamfer (C) and rounded shoulder (S), were produced with a dentin analog material and scanned with extraoral (E) or intraoral (I) scanners. The captured images were processed using CAD software to design a premolar. Blocks of LD were milled using a CAD/CAM system (Cad). For the pressing technique (Pre), crowns were first 3D printed using a polymeric material, and a heat-pressing protocol was performed. The design of experiments was used to plan four experimental groups (n = 10): (1) CadCI; (2) CadSE; (3) PreCE; and (4) PreSI. Two dependent variables were analyzed: (1) adaptation, measured using the replica technique; and (2) fracture load of the cemented crowns. Fractographic analysis was performed. Data were analyzed using ANOVA and regression statistical analyses.There was no significant effect of scanning method or finish line for the gap thickness in the different regions. For the processing method, Cad resulted in larger gap thickness in the occlusal, axial angle, and marginal areas and smaller gap in the axial area (P.001). There was no effect of the investigated factors on the fracture load. However, PreCE was considered to be the optimal design, as it achieved 100% of the desired fracture load (1,000 N) and 40% of the adaptation (200 μm).The optimal combination of factors for all-ceramic crowns is chamfer abutment preparation, extraoral scanning, and the press technique (combined with 3D printing).

This study evaluated the effect of clinical and patient-related factors on marginal bone loss. The sample was composed of individuals who were treated at two dental schools in southern Brazil. The variables evaluated were divided into individual (age, sex, diabetes, hypertension and antihypertensive use), and implant levels (arch, position, brand, protection, torque, time). After implant installation and following the second stage, periapical radiographs were obtained to measure the distance between the peri-implant bone crest and implant platform. Measurements were performed using ImageJ software. Data were analyzed using linear and Poisson multilevel regression. Fifty-eight patients with 113 implants were evaluated. The mean marginal bone loss was 0.45 ± 0.48 mm. Considering the linear multivariate model, age, diabetes, torque and time between surgery and reopening were found to be significant (p < 0.05). In the dichotomous model (bone loss

Objective: to compare the image quality obtained by six cameras used for dental documentation, including four DSLR cameras and two smartphones with different sensor size. Methods: the equipment determined the groups: APSCcan18-55 – Sensor APS-C Canon (EOS T5i) + 18-55 mm lens; APSCcan100 – Sensor APS-C Canon (EOS T5i) + 100 mm macro lens; APSCnik18-55 – Sensor APS-C Nikon (D5100) + 18-55 mm lens; APSCnik100 – Sensor APS-C Nikon (D5100) + 100 mm macro lens; ip1/3” – iPhone with 1/3-inch sensor; ga1/2.6”- Galaxy with 1/2.6-inch sensor. Two set of images -“dental documentation” and “small objects”- were obtained. The photographs were evaluated by three groups: US, undergraduate students; DS, dentists; and DP, dentists with photography experience. Scores between 0 and 10 were assigned. The results were compared by RM Anova and Tukey (α = 0.05). Results: the highest overall scores were obtained with APSCnik100 (8.5). For “dental documentation”, APSCcan18-55 and APSCnik18-55 showed the lowest values, even compared to ga1/2.6” (for US, DS and DP evaluators) and ip1/3” (for US evaluators). For “small objects”, DSLRs resulted in higher mean values compared to smartphones for US and DS. Conclusions: DSLR cameras with 18-55 mm lens and no circular flash should not be used for documentation photographs. DSLR cameras, regardless of lens, are superior to smartphones for small objects photographs.

Statement of problem Restorative materials are cemented on different types of substrates, such as dentin, metal, and glass-fiber posts with composite resin cores. Purpose The purpose of this in vitro study was to evaluate the failure behavior after cycling fatigue of a polymer-infiltrated ceramic network material (PICN; VITA ENAMIC) cemented on different supporting substrates. Material and methods PICN plates (N=80) were obtained from computer-assisted design and computer-assisted manufacturing (CAD-CAM) blocks and cemented with a resin cement to 4 different supporting substrates (n=20): (1) human dentin (PICNDen); (2) dentin analog (PICNDenAn); (3) nickel-chromium alloy (PICNNiCr); and (4) composite resin plus fiberglass post (PICNRc). For comparison, the fracture behavior of a feldspathic ceramic (FelDenAn; VITABLOCS Mark II) and an indirect composite resin (ResDenAn; Opallis LAB Resin) cemented to the DenAn substrate was investigated (n=20). Thus, specimens were composed of the restorative material layer (1-mm thick) resin cemented (0.1-mm-thick layer) to a 2-mm-thick supporting substrate. All specimens were subjected to mechanical cycling (MC) using a pneumatic cycling machine (500 000 cycles, 2 Hz, 50 N). Specimens that did not fracture during cycling were tested under compression using a universal testing machine at a cross-head speed of 0.5 mm/min until the sound of the first crack was detected using an acoustic system. Failure data were statistically evaluated using Weibull distribution. Failures were classified as radial crack, cone crack, combined, and catastrophic fracture. Results All FelDenAn specimens were fractured during MC. Only 4 PICNRc specimens survived MC, so their fracture load data were not statistically analyzed. PICNNiCr showed the greatest characteristic load (L0) value, followed by ResDenAn. Groups PICNDenAn and PICNDen showed lower and similar L0 but statistically different Weibull modulus (m). There was a significant relationship between experimental group and failure mode (P Conclusions The supporting substrate influenced the failure behavior of PICN. When the substrate had a higher elastic modulus than the restorative material, better mechanical behavior was observed.

Statement of problem Evidence is limited for the impact of clinical adjustments and polishing on the longevity of glazed lithium disilicate restorations. Purpose The purpose of this in vitro study was to evaluate the influence of surface finishing on the survival and success rates of lithium disilicate restorations based on fatigue resistance and failure mode. Material and methods Lithium disilicate (IPS e.max CAD) maxillary premolar crowns (N=54) were cemented on a dentin analog. The restorations were divided into 3 groups: overglaze (OG), abrasion (GA), and abrasion and polishing (AP). The crowns were submitted to cyclic fatigue in 37 oC water at 100 N and 2 Hz in 2 lifetimes. The load was applied to the occlusal surface by using anatomic pistons to simulate a clinical tripod occlusal contact. After cycling, the crowns were examined for failure (cracking, chipping, or catastrophic fractures) under optical and scanning electron microscopy. Cracking was considered either a structural failure (success analysis) or a survival (clinical criteria - survival analysis). Data were analyzed by using the log rank Kaplan-Meier and Holm-Sidak tests (α=.05). Results Surface finishing had no influence on the structural integrity of lithium disilicate, with similar success rates (P=.720). The calculated survival rate was higher for AP than that for other groups (P=.028). Cracking was found for GA and AP crowns, mostly initiating from the external surface. Chipping occurred in all experimental groups, and AP crowns did not show catastrophic failures. Conclusions Although surface treatments had no influence on the success of lithium disilicate, polishing showed a positive effect on the survival rate of the crowns based on the clinical implications of cracking (no need for replacement).

Conventional flexural strength tests of restorative materials neglect the effect of essential variables that can affect their mechanical behavior. The purpose of this study was to evaluate the effect of cementation on the mechanical behavior of a nanoceramic resin. A nanoceramic resin (LU) and a leucite-reinforced glass-ceramic (IE) were evaluated. Non-cemented specimens of the materials were produced and subjected to biaxial flexural strength test ( σ f , n = 30 ). Cemented specimens were constituted of the restorative material bonded with resin cement onto a dentin analog substrate. Cemented specimens were subjected to the monotonic compressive load test ( L f , n = 20 ). Vickers microhardness (HV) and translucency parameter (TP) of the materials were characterized. Data were analyzed using t-test (σf and TP), Mann-Whitney test (Lf and HV), and Weibull analysis (σf and Lf, α = 0 . 05). Non-cemented LU showed higher σf and Weibull modulus (m) than IE. When cemented to the substrate, LU showed higher Lf than IE; however, the m-value was similar among groups. LU showed lower HV than IE and higher TP values. Cementation influenced the mechanical behavior and failure mode of the nanoceramic resin. Resumo Os testes convencionais de resistência à flexão de materiais restauradores negligenciam o efeito de variáveis essenciais que podem afetar seu comportamento mecânico. O objetivo deste estudo foi avaliar o efeito da cimentação no comportamento mecânico de uma resina nanocerâmica. Foram avaliadas uma resina nanocerâmica (LU) e uma vitrocerâmica reforçada por leucita (IE). Foram produzidos corpos de prova (CP) não cimentados dos materiais e submetidos ao teste de resistência à flexão biaxial ( σ f , n = 30 ). CPs cimentados foram constituídos pelo material restaurador cimentado adesivamente a um substrato análogo à dentina. Os CPs cimentados foram submetidos ao teste de carga compressiva monotônica ( L f , n = 20 ). A microdureza Vickers (HV) e o parâmetro de translucidez (TP) dos materiais foram caracterizados. Os dados foram analisados pelo teste t (σf e TP), teste de Mann-Whitney (Lf e HV) e análise de Weibull (σf e Lf, α = 0 . 05). A LU não cimentada apresentou σf e módulo de Weibull (m) superiores a IE. Quando cimentada ao substrato, a LU apresentou maior Lf que a IE; no entanto, o valor de m foi semelhante entre os grupos. A LU apresentou menor HV que a IE e maiores valores de TP. Concluiu-se que a cimentação influenciou o comportamento mecânico e modo de falha da resina nanocerâmica.

Objective To evaluate the bond strength of a polymer-infiltrated ceramic-network (PICN) material and to composite repair after different surface treatments. Materials and methods Eighteen blocks of the PICN material were obtained from CAD/CAM blocks, aged and randomly divided into 2 groups: 5% hydrofluoric acid (HF) or sandblasting with aluminum oxide particles (SAND). For each condition, three treatments were tested: silane (Sil), silane-containing adhesive (Ad), or silane + silane-containing adhesive (SilAd). The treated PICN surfaces were restored with composite resin. The microtensile bond strength test was performed in a universal testing machine, and data (MPa) were compared with two-way Analysis of variance (anova) and Tukey (α = 0.05). Roughness (Ra) and contact angle (CA) were obtained after HF and SAND conditions. Results The greatest bond strength values were obtained for the groups Sil and SilAd, for both HF and SAND pretreatments. The Ra values of SAND were statistically greater than HF. The CA generated by the adhesive on SAND surface was lower than HF surface. Conclusions The use of silane improves the bond strength of the composite repair to PICN substrate compared to the single use of silane-containing adhesive. The HF pretreatment is most indicated when the silane-containing adhesive is applied alone. Clinical significance Fractured PICN restorations can be repaired with composite resin, because the surface is treated with hydrofluoric acid or sandblasting followed by the individual use of silane.

Purpose Implant supported full-arch immediate prosthesis (also called the immediate Branemark protocol) revolutionized dental clinical practice due to the aesthetic/functional benefits it offers to the patient. This work presents a simplified and efficient technique for implant supported full-arch immediate prosthesis fabrication. Methods After diagnosing the necessity of the protocol, the implants were installed with a minimum torque of 35Ncm. For implant impression, the use of previously prepared castable cylinders (dispensing with impression posts), and a U-shaped acrylic (Mello technique) generated a cast without distortion. The Branemark protocol was fabricated on this cast without the metal test specimen. Conclusion The simplified technique proposed in this article for Branemark protocol fabrication seemed to be effective.

O bjective: This study evaluated the effect of drying times of two total-etch & rinse adhesives on the resin bond strength to a feldsphatic ceramic, before and after aging. Material and Methods: Feldsphatic-ceramic CAD-CAM bars were cut into blocks (12×10×4 mm) with a cutting machine (N = 32). Impressions were made of each ceramic block with silicone putty material and the negative space was filled with a composite resin. The bonding ceramic surface was etched with hydrofluoric acid, silanized, and the adhesive system (SB- Single Bond 2, 3M-ESPE; or PB- Prime & Bond NT, Dentsply) was applied. The samples were dried at different times (5, 10 and 15 s) before the cementation. The resin and ceramic blocks were cemented by a dual cure resin cement. All samples were stored in distilled water at 37 °C for 24 h. For the μ-TBS test, the samples were sliced into microbars. Half of the bars of each block was tested after 24 h and, the other bars were submitted to thermocycling (12,000×) and water storage (150 d) . For the 24 h groups, the longer drying time increased (p < 0.05) the bond strength of SB (water/alcohol adhesive), while reduced (p < 0.05) for the PB group (acetone based adhesive). Results: For the aged groups, the bond strength for the different drying times had no significant difference, for the both adhesives. Conclusion: Longer drying times increased the bond strength values of SB. Smaller drying times increased the bond strength values of PB. The aging protocol influenced the bond strength of SB groups. Keywords: Microtensile; Adhesion; Feldspar ceramic; Drying time; Adhesive system.

To evaluate the critical bond strength (σ) of ceramic and metal brackets to a lithium disilicate-based glass–ceramic. Two hundred and forty ceramic specimens (IPS e-max CAD) were randomly distributed in 12 experimental groups (n = 20). Two ceramic brackets (monocrystalline, BCm; and polycrystalline, BCp) and a metal bracket (BM) were bonded to glass–ceramic specimens after one of the following surface treatments: HF—hydrofluoric acid applied for 60 s; S—silane applied for 3 min; HFS—HF followed by S; and MDP—application of an adhesive containing a phosphate monomer (MDP). All brackets were bonded to the treated glass–ceramic using a resin cement, stored in 37 °C water for 48 h before shear bond strength testing. Optical (OM) and scanning electron (SEM) microscopies were used for fractographic analysis. Data was statistically analyzed using Kruskal–Wallis and Student–Newman–Keuls (α = 0.05). BCm bonded to glass–ceramic treated with either HFS or HF showed the highest median σ values, respectively, 10.5 MPa and 8.5 MPa. In contrast, the BCp bonded to glass–ceramic treated with MDP showed the lowest median σ value (0.8 MPa), which was not statistically different from other MDP-treated groups. The failure mode was governed by the glass–ceramic surface treatment, not by the bracket type. Quantitative (σ values) and qualitative (fracture mode) data suggested a minimum of 5 MPa for brackets bonded to glass–ceramic, which is the lower critical limit bond strength for a comprehensive orthodontic treatment. Bonding brackets to glass–ceramic requires micromechanical retention.

This study aimed to characterize the fatigue behavior using two fatigue methods, boundary and staircase, and to predict the probability of failure (Pf) of zirconia-reinforced lithium silicate glass-ceramic (ZLS). Bar-shaped specimens of ZLS (18 ×4 ×1.2 mm) were fabricated. Thirty specimens were subjected to a three-point flexural strength test using a universal testing machine with 0.5 mm/min crosshead speed, in 37 °C distilled water. Flexural strength data were analyzed with Weibull statistics. Eighty-six bars were subjected to cyclic fatigue using boundary and staircase methods. Fatigue tests were performed in a pneumatic cycling machine (2 Hz, 37 °C distilled water) for 10 ³ and 104 cycles. Fatigue data were analyzed using an inverse power law relationship and log normal-lifetime distribution. Fracture toughness (KIc) was determined using V-notched specimens (18 ×4 ×3 mm) and the short beam toughness method (n = 7). Vickers hardness (VH) was evaluated (4.9 N, 20 s). Fractographic and EDS analyses were also performed. ZLS showed a characteristic strength of 197 MPa, Weibull modulus of 4, VH of 6.67 GPa and KIc of 1.93 MPa m1/2. After 103 cycles, for both methods, there was a degradation of 78% of the initial strength. There was no significant degradation when the number of cycles increased from 103 to 104. Both methods resulted in similar Pf and precision at 40 MPa (~50% Pf). Yet, staircase shows good accuracy and precision in predicting the stress amplitude for a P f near 50%; while boundary is also effective for P f lower than 50%. The fatigue methods evaluated show similar accuracy and precision for predicting the Pf of a glass-ceramic when simulations were made in the range of stress levels and lifetimes used in the fatigue tests.

Objectives Ceramics and composites are the most used materials for dental application. Recently, the characteristics of both were combined on the called "polymer-infiltrated ceramic-network" (PICN). The aim of this review is to report the behavior of PICN, comparing the findings that may support the correct clinical application. Overview The PICN material is a structure with a sintered ceramic matrix infiltrated with a polymer matrix. Studies evaluated this material microstructure and composition, mechanical properties and adhesive behavior. The most cited mechanical properties are flexural strength, compressive strength, elastic modulus, Weibull modulus, hardness, fracture toughness and fatigue resistance. Most studies compared PICN with feldspathic porcelain, lithium disilicate glass-ceramic, lithium silicate, zirconia-reinforced glass-ceramic, leucite reinforced glass-ceramic, polycrystalline alumina and zirconia. Other studies evaluated a similar material (a nanoceramic resin). Clinical significance The mechanical properties of the PICN are equivalent to the properties of nanoceramic resins, lower to lithium disilicate glass ceramic and superior to feldspathic porcelain. Yet, the findings suggest a highly resistant material to degradation at low loads (close to physiological situation) when cemented on a substrate.

Objectives To compare the lifetime of Y-TZP/porcelain crowns under three different load conditions using step-stress accelerated lifetime testing. Methods The Y-TZP frameworks were milled using CAD/CAM, veneered with a porcelain and cemented onto dentine analogue dies. Specimens were divided according to the occlusal load condition ( n = 20): central fossa load (CFL), cusp tip load (CTL) and sliding contact (SC). For CFL and CTL, the cyclic load was applied parallel to the long axis of the preparation using a ceramic piston. For SC, the axial load was associated to 1 mm lateral displacement at the disto-lingual cusp. Different stress profiles were used. Failures were detected with an acoustic system. A Weibull distribution (95% confidence boundary) was used to analyse the data, and fractographic principles were used to evaluate fractured specimens. Results The acoustic monitor was able to detect the initial crack. The probability of failure (at 300 N load and 200,000 cycles) was statistically greater for CTL (0.63; 0.44–0.81) compared to CFL (0.23; 0.12–0.43). The Weibull modulus of CFL (2.1; 1.5–3.6) was greater than for SC (0.7; 0.5–1.2), with no difference in the lifetime. All specimens failed by chipping, which originated predominantly at the contact (66.7%) on CTL, and in the bulk of the porcelain on CFL (100%) and SC (80%). Conclusions Contact at the cusp tip is more harmful than at the central fossa. Data from sliding contact are less consistent than from axial contacts, but more clinically relevant. Clinical significance The loading condition of Y-TZP/porcelain crowns can influence on the probability of failure and failure mode. The contact at the cusp tip is more harmful than at the central fossa, where the stress is better distributed. Sliding contact is a better simulator of the chewing cycle compared to axial contacts.

Objetivo: Avaliar a influência da manipulação de uma resina composta (RC) com diferentes luvas na sua resistência adesiva à dentina. Metodologia: 25 terceiros molares hígidos foram seccionados 2 mm abaixo do sulco central, expondo a dentina (D). A D foi condicionada com ácido fosfórico 35%, lavada, e o sistema adesivo Single Bond Universal (3M ESPE) foi aplicado. Os dentes foram distribuídos aleatoriamente em 5 grupos, de acordo com o tipo da manipulação da RC: C (controle)- RC inserida diretamente do tubo para a D; LL- RC manipulada com luvas de látex antes da inserção; LV- RC manipulada com luvas de vinil; LC- RC manipulada com luvas de látex contaminadas; VC- RC manipulada com luvas de vinil contaminadas. Após, o conjunto foi seccionado em uma máquina de corte para a obtenção dos palitos com área aproximada de 1 mm², que foram armazenados em água destilada a 37°C por 6 meses. O teste foi realizado em uma máquina de ensaio (EMIC), com velocidade de 0,5 mm/min. Os valores de resistência adesiva foram calculados (MPa) e comparados com ANOVA, Tukey (α=0,05) e Weibull. Resultados: O grupo com maior resistência adesiva foi o LV (38,74 ± 3,63 MPa), estat Método: Foi aplicado questionário a 164 docentes do ensino fundamental do Município de Almirante Tamandaré/PR, do período vespertino, para avaliação do nível de conhecimento sobre as atitudes no pronto-atendimento a crianças em caso de TAD. Os professores responderam ao QTDA (Questionário sobre o pronto atendimento ao traumatismo alvéolo dentário), que continham 10 (dez) perguntas de múltipla escolha. O questionário contém questões sobre a atitude a ser tomada em caso de traumatismo na dentição decídua (n = 5) e na dentição permanente (n = 5), sendo estas referentes a situações de avulsão, intrusão, extrusão e fratura dentária. Cada pergunta continha de 4 a 5 opções de resposta, sendo possível, ao respondente, descrever outra atitude, caso não considerasse nenhuma das alternativas como correta. O QTDA foi respondido em dois momentos, um anterior a leitura de folheto educativo (QTDA1) e outro posterior a sua leitura (QTDA2). Resultado: Observou-se que 43,20% dos docentes não tinham conhecimento sobre os procedimentos corretos a serem adotados numa situação de TAD. Após a leitura do panfleto educativo, a taxa de acerto aumentou cerca de 21,83%, ou seja, houve diferença estatisticamente significante (p≤0,001) entre os escores antes e depois da leitura do panfleto, o que reflete uma melhora no nível de conhecimento por parte dos respondentes. Conclusão: O folheto educativo mostrou-se eficiente na aquisição de conhecimento sobre o tema TAD, resultando num percentual significativamente positivo após a leitura do folheto educativo, sendo método barato e, os educadores fazem a leitura onde e quando achar conveniente.

Statement of problem Variables involving the indication, manufacturing, and clinical use of ceramic restorations make the standardization of in vitro studies a challenge and raise questions as to the clinical validity of the resulting data. Purpose The purpose of this in vitro study was to assess the effect of piston material on the fracture behavior of ceramics tested under compressive load. Material and methods Two ceramics were evaluated: a lithium disilicate–based glass-ceramic (D) and a feldspathic porcelain (P). Plate-shaped ceramic specimens (1.5-mm thick) were adhesively cemented onto a dentin analog substrate. The specimens from each ceramic were divided into 4 groups according to the piston material (n=20): metal (M) (stainless steel), composite resin (R) (NEMA-G10, fiber-reinforced epoxy resin), ceramic (C) (lithium disilicate–based glass-ceramic), and human tooth (T) (canine). A gradual compressive load (0.5 mm/min) was applied to the center of the specimen with a universal testing machine. The test was performed in 37°C distilled water, and the initial crack was detected by using an acoustic system. The fracture load values (N) were statistically analyzed with the Kruskal-Wallis and Dunn tests (α=.05). A finite element analysis (FEA) was also performed. Results Piston material had no influence on fracture load and failure mode of ceramic D. Ceramic P showed higher fracture load values when loaded with the composite resin piston. Ceramic P showed more combined failures (cone crack and radial crack) than D. The FEA showed a distinct stress distribution for R piston on P. Pistons C and T resulted in similar stress distribution, fracture load, and failure mode for both ceramics. Conclusions The effect of piston material on the ceramic fracture behavior depends on the ceramic being evaluated.

Purpose: To evaluate the influence of the geometry and design of prosthetic crown preparations on stress distribution in compression tests, using finite element analysis (FEA). Materials and Methods: Six combinations of 3D drawings of all-ceramic crowns (yttria-stabilized zirconia framework and porcelain veneer) were evaluated: F, flat preparation and simplified crown; FC, flat preparation and crown with contact point; FCM, flat preparation and modified crown; A, anatomical preparation and simplified anatomical crown framework; AC, anatomical preparation and crown with contact point; and ACM, anatomical preparation and modified crown. Bonded contact types atallinterfaceswiththemeshwereassigned,andthematerialpropertiesusedwereaccordingtotheliterature.A200Nverticalloadwasappliedatthecenterofeachmodel. The maximum principal stresses were quantitatively and qualitatively analyzed. Results: The highest values of tensile stress were observed at the interface between the ceramics in the region under the load application for the simplified models (F and A). Reductions in stress values were observed for the model with the anatomical preparation and modified infrastructure (ACM). The stress distribution in the flat models was similar to that of their respective anatomical models. Conclusions: The modified design of the zirconia coping reduces the stress concentration at the interface with the veneer ceramic, and the simplified preparation can exert a stress distribution similar to that of the anatomical preparation at and near the load point, when load is applied to the center of the crown.

Objectives: The aim of this study was to evaluateby electromyography the activity of the temporalisand masseter muscles in removable partial dentures(RPDs) users, before and after new RPDs installation.Material and Methods: Ten patients were selectedfor this study. All subjects were edentulous in theposterior mandibular region (Kennedy class I orII), fully dentate in the antagonist arch, and dentalprosthesis users, which needed to be replaced. Theelectromyographic activity (EMG) recorded thesuperficial masseter and temporalis muscles, duringthe maximum voluntary bite force and the restposition. Maximum mouth opening was also verified.The measurements were recorded at four specifictimes: using the old prosthesis (T0), right after thenew prosthesis installation (T1), two weeks (T2) andfour weeks (T4) after installing the new prosthesis.All the RPDs were made by an experienced dentistand the same laboratory. Data were statisticallyanalyzed by ANOVA and Tukey tests (? = 0.05).Results: EMG values had high standard deviation atthe time T0. Generally, the mean values decreasedafter new prosthesis installation, especially aftertwo weeks from the installation (T2). During therest position, the left masseter and left temporalismuscles showed statistically significant gradualdecrease in their activities over time. Conclusion:New prostheses have positive effect on the patient’smuscular activity. However, an adaptation period ofthe muscle fibers to the new prosthesis is needed.KeywordsElectromyographic activity; Dental occlusion; Masseter; Removable partial dentures; Temporalis.

Objective: To report two cases of low level laser therapy used in the treatment of muscle pain caused by temporomandibular disorders (TMDs). Methods: Two patients of the São José dos Campos Dental School (UNESP) were selected and subjected to eight applications of low level laser therapy (diode). Laser was punctually applied on masseter and temporalis muscles bilaterally. Three methods were used to evaluate the effectiveness of treatment: pressure algometer, visual analog scale (VAS) and maximal mouth opening. Each measure was performed before and after the laser therapy session. The results were subjected to statistical analysis (ANOVA two factors and Tukey's test, ? = 0.05). Results: For both patients, no significant difference was found between the results obtained by algometer before and after laser application within each session. Nonetheless, VAS showed a tendency to lower values after laser application. The highest values obtained by the pressure algometer were found between days 9 (fourth application) and 16 (sixth application), in both cases. Both patients had an improvement in mouth opening. Conclusions: The assessment methods used were quite practical to register the pain before and after treatment. Therapy with low level laser seems to have a beneficial effect for muscle pain of temporomandibular joint (TMJ).

Objective To investigate the influence of the convergence angle of tooth preparation on the fracture load of Y-TZP-based ceramic (YZ – Vita YZ) substructure (SB) veneered with a feldspathic porcelain (VM9 – Vita VM9). Methods Finite element stress analysis (FEA) was performed to examine the stress distribution of the system. Eighty YZ SB were fabricated using a CAD–CAM system and divided into four groups ( n = 20), according to the total occlusal convergence (TOC) angle: G6 – 6° TOC; G12 – 12° TOC; G20 – 20° TOC; and G20MOD – 20° TOC with modified SB. All SB were veneered with VM9, cemented in a fiber reinforced epoxy resin die, and loaded to failure. Half of the specimens from each group ( n = 10) were cyclic fatigued (10 6 cycles) before testing. Failure analysis was performed to determine the fracture origin. Data were statistically analyzed using Anova and Tukey's tests ( α = 0.05). Results The greatest mean load to fracture value was found for the G20MOD, which was predicted by the FEA. Cyclic fatigue did not significantly affect the load of fracture. Catastrophic failure originating from the internal occlusal surface of the SB was the predominant failure mode, except for G20MOD. Significance The YZ–VM9 restorations resisted greater compression load than the usual physiological occlusal load, regardless of the TOC angle of preparations. Yet, the G20MOD design produced the best performance among the experimental conditions evaluated.

Statement of problem Investigating the mechanical behavior of ceramics in a clinically simulated scenario contributes to the development of new and tougher materials, improving the clinical performance of restorations. The optimal in vitro environment for testing is unclear. Purpose The purpose of this in vitro study was to investigate the failure behavior of a leucite-reinforced glass-ceramic under compression loading and fatigue in different simulated oral environment conditions. Material and methods Fifty-three plate-shaped ceramic specimens were produced from computer-aided design and computer-aided manufactured (CAD-CAM) blocks and adhesively cemented onto a dentin analog substrate. For the monotonic test (n=23), a gradual compressive load (0.5 mm/min) was applied to the center of the specimens, immersed in 37oC water, using a universal testing machine. The initial crack was detected with an acoustic system. The fatigue test was performed in a mechanical cycling machine (37oC water, 2 Hz) using the boundary technique (n=30). Two lifetimes were evaluated (1×10 6 and 2×10 6 cycles). Failure analysis was performed using transillumination . Weibull distribution was used to evaluate compressive load data. A cumulative damage model with an inverse power law (IPL) lifetime-stress relationship was used to fit the fatigue data. Results A characteristic failure load of 1615 N and a Weibull modulus of 5 were obtained with the monotonic test. The estimated probability of failure (P f ) for 1×10 6 cycles at 100 N was 31%, at 150 N it was 55%, and at 200 N it was 75%. For 2×10 6 cycles, the P f increased approximately 20% in comparison with the values predicted for 1×10 6 cycles, which was not significant. The most frequent failure mode was a radial crack from the intaglio surface. For fatigue, combined failure modes were also found (radial crack combined with cone crack or chipping). Conclusions Fatigue affects the fracture load and failure mode of leucite-reinforced glass-ceramic.

Statement of problem Ceramic restorations often require adjustments using diamond rotary instruments, which damage the glazed surface. The effect of these adjustments on the fracture behavior of these restorations is unclear. Purpose The purpose of this in vitro study was to evaluate the influence of induced surface defects on the fracture load and mode of failure of lithium disilicate–based (LDS) glass ceramic restorations. Material and methods Premolar crowns were obtained from LDS computer-aided design and computer-aided manufacturing blocks (n=60) and glazed. The crowns were bonded to dentin analog dies and divided into 5 groups (n=12), as follows: glaze; abrasion (diamond rotary instrument 2135); abrasion and reglaze; abrasion and polishing (diamond rotary instrument 2135F, 2135 FF, and polishing devices); and polishing. The topography of the crowns was examined by scanning electron microscopy, and roughness was measured. A compressive load (0.5 mm/min) was applied by a piston to the center of the lingual cusp until fracture. The fracture load was recorded and data were statistically analyzed by ANOVA and the Tukey HSD test (α=.05). Fractured crowns were examined to determine the fracture origin. Results Polishing and/or reglazing resulted in lower roughness than for the abraded group ( P P =.696). Catastrophic fracture with origin at the intaglio surface was the mode of failure for all the crowns. Conclusions The experiment design successfully submitted the crowns to a clinical stress state, resulting in a clinically relevant failure. Reglazing or polishing were effective in reducing surface defects. Surface treatments had no effect on the immediate catastrophic failure of LDS crowns.

Objectives To evaluate the reliability of monolithic and multilayer ceramic structures used in the CAD-on technique (Ivoclar), and the mode of failure produced in ceramic structures bonded to a dentin analog material (NEMA-G10). Methods Ceramic specimens were fabricated as follows (n = 30): CAD-on- trilayer structure (IPS e.max ZirCAD/IPS e.max Crystall./Connect/IPS e.max CAD); YLD- bilayer structure (IPS e.max ZirCAD/IPS e.max Ceram); LDC- monolithic structure (IPS e.max CAD); and YZW- monolithic structure (Zenostar Zr Translucent). All ceramic specimens were bonded to G10 and subjected to compressive load in 37 °C distilled water until the sound of the first crack, monitored acoustically. Failure load (Lf) values were recorded (N) and statistically analyzed using Weibull distribution, Kruskal–Wallis test, and Student-Newman–Keuls test (α = 0.05). Results Lf values of CAD-on and YZW structures were statistically similar (p = 0.917), but higher than YLD and LDC (p Significance Monolithic zirconia (YZW) and CAD-on structures showed similar failure resistance and reliability, but a different fracture behavior.

O objetivo do estudo foi verificar o comportamento de fratura de corpos-de-prova (CP) cerâmicos submetidos a dois métodos de ensaio mecânico, flexão biaxial e carga compressiva monotônica. Foram confeccionados 200 CP cerâmicos (120 cimentados e 80 não cimentados), em 4 configurações: CAD-on (e.max ZirCAD + Crystall/Connect + e.max CAD) YLD (e.max ZirCAD + e.max Ceram) LDC monolítico (e.max CAD) YZW monolítico (Zenostar). Os CP (n30) foram cimentados (Multilink N, Ivoclar) em bases de resina epóxica (G10) e submetidos à carga compressiva monotônica (EMIC) com velocidade de 0,5 mm/min, em água destilada (37ºC), o restante dos CP (n20) foram submetidos a flexão biaxial. As falhas foram avaliadas usando princípios de fractografia e transiluminação. Os dados foram analisados por Kurskal-Wallis e teste de Dunn´s que mostraram diferença estatística entre os grupos experimentais (p

Made available in DSpace on 2018-12-11T17:26:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 The aim of the present study is to investigate the effect of aging type (thermocycling vs. water storage) and aged unit (block vs. stick) on the repair strength of resin composite to feldspathic porcelain in testing microtensile bond strength (TBS). Ceramic specimens (N = 30) (10 × 5.7 × 4.5 mm3, Vita Mark II, Vita) were obtained from CAD-CAM blocks. One surface was etched with 10% HF and silanized. An adhesive was applied and resin composite blocks were constructed incrementally on the conditioned surface. The specimens were randomly divided into five groups (n = 6): Control (C): Non-aged; BTC: Blocks were thermocycled (5-55 °C, 6000 cycles); STC: Sticks were thermocycled; BS: Blocks aged in water storage (6 months) after themocycling; SS: Blocks aged in water storage (6 months) after thermocycling. After TBS test, failure types were classified. Data (MPa) were statistically analyzed (1-way and Dunett and 2-way ANOVA, Tukey's) (α = 0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m), and shape (0) values were calculated. Aging type (p = 0.009) and aged unit (p = 0.000) significantly affected the results. Interaction terms were also significant (p = 0.000). Considering the stick level, there was no significant difference between thermocycling (STC: 25.7 ± 2.3) and water storage (SS: 25.3 ± 3.8) (p > 0.05) but the results were significantly higher when blocks were thermocycled (BTC: 31.6 ± 2.9) (p < 0.05). Weibull modulus and characteristic strength was the highest in BTC (m = 4.2; σo: 34.4) among all other groups (m = 3-3.9; σo: 14.6-28.5). Adhesive failures were common and cohesive failures occurred in less than 5% in all groups. Aging protocol was detrimental on durability of repair strength of resin composite to feldspathic porcelain. Exposing the sticks to either thermocycling or water storage aging should be considered in in vitro studies. Post-graduation Program in Dentistry Dental School University of Passo Fundo Department of Dental Materials and Prosthodontics Institute of Science and Technology Sao Paulo State University (UNESP) Department of Dentistry Federal University of Rio Grande Do Norte/UFRN Clinic for Fixed and Removable Prosthodontics and Dental Materials Science Center for Dental and Oral Medicine Dental Materials Unit University of Zurich Department of Dental Materials and Prosthodontics Institute of Science and Technology Sao Paulo State University (UNESP)

Made available in DSpace on 2018-12-11T16:58:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-08-10 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Purpose This study aimed to evaluate the effect of heat treatment (at 77 °C) of a silanized feldspathic ceramic on microtensile bond strength (μTBS) with a resin cement before and after being aged by thermocycling. Material and methods Twenty-four blocks (12×10×4 mm3) of a CAD/CAM feldspathic ceramic (Vitablocks Mark II, Vita) were obtained and randomly divided into three groups, according to the surface treatment prior to the cementation: Group AS - hydrofluoric acid 10%+silane; Group S77 - silane+heating at 77 °C for 60 s; and Group AS77 - hydrofluoric acid 10%+silane+heating at 77 °C for 60 s. Ceramic blocks were cemented to composite resin blocks with a resin cement. The sets were subsequently cross-sectioned into 1 mm2 beams for μTBS testing. The beams of each group were randomly divided into two subgroups: aging (thermocycling, 12,000 cycles between 5 °C and 55 °C) and non-aging (tested immediately). One-way ANOVA and Tukey's test (α=0.05) and Weibull analysis (95% CI) were used to analyze the data. Results Group AS77 had the lowest pre-test failure number during the cutting among the groups. There was no significant difference (p=0.255) between the μTBS mean values of the non-aged groups. After aging, the mean value of S77 was significantly lower than those of AS77 and AS (p=0.005). There was no difference in the Weibull modulus (m) and characteristic strength (σ0) of the aged and non-aged groups for all comparisons. Before aging, heat treatment of silanized feldspathic ceramic (non acid-etched surface) demonstrated bond strength similar to that achieved with hydrofluoric-acid-etching treatment however, it had lower bond strength after aging. Conclusion The combination of hydrofluoric-acid-etching treatment with heat treatment silanized feldspathic ceramic did not improve the bond strength of the interface. Department of Dental Materials and Prosthodontics, Institute of Science and Technology of São José dos Campos, São Paulo State University (UNESP), Street Francisco José Longo, No. 777, Jardim São Dimas Post-graduation Program in Dentistry, Dental School, University of Passo Fundo, BR 285, Km 171 Department of Restorative Dentistry, Institute of Science and Technology of São José dos Campos, São Paulo State University (UNESP), Av. José Longo, No. 777, Jardim São Dimas Prosthodontics Unit, Faculty of Odontology, Federal University of Santa Maria, Brazil Street Floriano Peixoto, 1184 Department of Dental Materials and Prosthodontics, Institute of Science and Technology of São José dos Campos, São Paulo State University (UNESP), Street Francisco José Longo, No. 777, Jardim São Dimas Department of Restorative Dentistry, Institute of Science and Technology of São José dos Campos, São Paulo State University (UNESP), Av. José Longo, No. 777, Jardim São Dimas FAPESP: 2012/10573-5

To investigate the influence of CAD-CAM diamond bur deterioration on surface roughness (Ra) and maximum failure load (Lf) of Y-TZP-based ceramic (YZ) substructures (SB) veneered with a feldspathic porcelain.Two sets of burs (B1 and B2) were used to fabricate 30 YZ SB each in a CAD/CAM system (Cerec InLab). The SB were identified (1-30) according to the milling sequence (MS). SEM images of the burs were recorded before milling, and after milling 15 and 30 SB. The SB Ra was measured. All SB were veneered, cemented onto a fiber reinforced epoxy resin die, and loaded to failure. Specimens from B1 group were cyclic fatigued (106 cycles) before loading to failure. Fractographic analysis was performed. Data were statistically analyzed using Student's t-test, Weibull analysis, Pearson's correlation and ANOVA (α= 0.05).The mean Ra value of B1 specimens was statistically greater than B2. Weibull modulus of B1 and B2 were statistically similar. The correlation between MS and Lf was not statistically significant for the groups. MS and Ra had significant correlation for both groups (B1: r= -0.514, P= 0.015; B2: r= -0.462, P= 0.03). Although the visual aspect (SEM) of the burs was similar after 30 millings, the mean Ra values were significantly different after 27 millings for B1 and 24 millings for B2.

To evaluate the effect of diamond-like carbon (DLC) coating of prefabricated implant abutment on screw removal torque (RT) before and after mechanical cycling (MC).Fifty-four abutments for external-hex implants were divided among 6 groups (n = 9): S, straight abutment (control); SC, straight coated abutment; SCy, straight abutment and MC; SCCy, straight coated abutment and MC; ACy, angled abutment and MC; and ACCy, angled coated abutment and MC. The abutments were attached to the implants by a titanium screw. RT values were measured and registered. Data (in Newton centimeter) were analyzed with analysis of variance and Dunnet test (α = 0.05).RT values were significantly affected by MC (P = 0.001) and the interaction between DLC coating and MC (P = 0.038). SCy and ACy showed the lowest RT values, statistically different from the control. The abutment coated groups had no statistical difference compared with the control. Scanning electron microscopy analysis showed DLC film with a thickness of 3 μm uniformly coating the hexagonal abutment.DLC film deposited on the abutment can be used as an alternative procedure to reduce abutment screw loosening.

Objectives To characterize the microstructure and determine some mechanical properties of a polymer-infiltrated ceramic-network (PICN) material (Vita Enamic, Vita Zahnfabrik) available for CAD–CAM systems. Methods Specimens were fabricated to perform quantitative and qualitative analyses of the material's microstructure and to determine the fracture toughness ( K Ic ), density ( ρ ), Poisson's ratio ( ν ) and Young's modulus ( E ). K Ic was determined using V-notched specimens and the short beam toughness method, where bar-shaped specimens were notched and 3-point loaded to fracture. ρ was calculated using Archimedes principle, and ν and E were measured using an ultrasonic thickness gauge with a combination of a pulse generator and an oscilloscope. Results Microstructural analyses showed a ceramic- and a polymer-based interpenetrating network. Mean and standard deviation values for the properties evaluated were: K Ic = 1.09 ± 0.05 MPa m 1/2 , ρ = 2.09 ± 0.01 g/cm 3 , ν = 0.23 ± 0.002 and E = 37.95 ± 0.34 GPa. Significance The PICN material showed mechanical properties between porcelains and resin-based composites, reflecting its microstructural components.

To evaluate the influence of the geometry and design of prosthetic crown preparations on stress distribution in compression tests, using finite element analysis (FEA).Six combinations of 3D drawings of all-ceramic crowns (yttria-stabilized zirconia framework and porcelain veneer) were evaluated: F, flat preparation and simplified crown; FC, flat preparation and crown with contact point; FCM, flat preparation and modified crown; A, anatomical preparation and simplified anatomical crown framework; AC, anatomical preparation and crown with contact point; and ACM, anatomical preparation and modified crown. Bonded contact types at all interfaces with the mesh were assigned, and the material properties used were according to the literature. A 200 N vertical load was applied at the center of each model. The maximum principal stresses were quantitatively and qualitatively analyzed.The highest values of tensile stress were observed at the interface between the ceramics in the region under the load application for the simplified models (F and A). Reductions in stress values were observed for the model with the anatomical preparation and modified infrastructure (ACM). The stress distribution in the flat models was similar to that of their respective anatomical models.The modified design of the zirconia coping reduces the stress concentration at the interface with the veneer ceramic, and the simplified preparation can exert a stress distribution similar to that of the anatomical preparation at and near the load point, when load is applied to the center of the crown.

To evaluate the effect of the cementation strategy and mechanical cycling (MC) on the microtensile bond strength (MTBS) of feldspathic inlays cemented to premolars.Forty-eight human premolars were prepared and porcelain inlays were produced. Specimens were allocated into 3 groups, based on the cementation strategy: 1) conventional adhesive cementation (RelyX ARC, 3M ESPE): application of etch-and-rinse single bottle adhesive to dentin / ceramic surface treated with hydrofluoric acid (HF) and silane (S) / cementation with resin cement; 2) simplified cementation using a self-adhesive resin cement (RelyX U100, 3M ESPE); 3) modified simplified cementation using a self-adhesive resin cement (RelyX U100, 3M ESPE) with HF+S treatment. Half of the specimens from each group were submitted to MC (2x106 pulses, frequency = 4 Hz, load = 100 N). Each specimen was serially sliced for MTBS and the failures were classified. The stress distribution analysis using FEA was verified.All of the bar-samples from G2 were lost during cutting of the specimens. Mechanical-cycling had no significant effect on bond strength, whereas cementation strategy significant affected MTBS results. The most common type of failure was cohesive of cement. FEA showed that stresses were concentrated mainly at the loading region going up to the root fixation.Porcelain inlays cemented with conventional resin cement or self-adhesive resin cement should be associated with ceramic surface treatment. FEA showed the most critical zone for failure is located in the cement region close to the marginal crest.

To evaluate the effect of post-silanization heat treatment of a silane agent and rinsing with hot water of silanized CAD/CAM feldspathic ceramic surfaces on the microtensile bond strength between resin cement and the ceramic, before and after mechanical cycling.Blocks measuring 10 x 5.7 x 3.25 mm3 were produced from feldspathic ceramic cubes (VITA Mark II, VITA Zanhfabrik). Each ceramic block was duplicated in composite resin using a template made of polyvinylsiloxane impression material. Afterwards, ceramic and corresponding resin composite blocks were ultrasonically cleaned and randomly divided according to the 5 strategies used for conditioning the ceramic surface (n = 10): GHF: etching with hydrofluoric acid 10% + rinsing with water at room temperature + silanization at 20°C; G20: silanization; G77: silanization + oven drying at 77°C; G20r: silanization + hot water rinsing; G77r: silanization + oven drying at 77°C + hot water rinsing. The resin and ceramic blocks were cemented using a dualcuring resin cement. Every group was divided in two subgroups: aging condition (mechanical cycling, designated as a) or non-aging (designated as n). All the bonded assemblies were sectioned into microsticks for microtensile bond strength (µTBS) testing. The failure mode of the tested specimens was assessed and µTBS data were statistically analyzed in two ways: first 2-way ANOVA (GHF, G20 and G77 in non-aging/aging conditions) and 3-way ANOVA (temperature x rinsing x aging factors, excluding GHF), followed by Tukey's test (p = 0.05).The 2-way ANOVA revealed that the µTBS was significantly affected by the surface treatment (p0.001) but not by aging (p = 0.68), and Tukey's test showed that G77-n/G77-a (18.0 MPa)GHF-n/GHF-a (12.2 MPa)G20-n/G20-a (9.1 MPa). The 3-way ANOVA revealed that the µTBS was significantly affected by the "heat treatment" and "rinsing" factors (p0.001), but not affected by "aging" (p = 0.36). The rinsing procedure decreased, while oven drying increased the bond strengths. Group G77, in both non-aging and aging conditions (18.6-17.4 MPa), had the highest bond values. Failure modes were mainly mixed for all groups.Oven drying at 77°C improved the bond strength between the resin cement and feldspathic ceramic, but hot water rinsing reduced the bond strength and should not be recommended.

Objectives: This study evaluated the microtensile bond strength (MTBS) of non-aged and aged resin-based composites (RBC) (nanohybrid and nanofilled) after two surface conditioning methods, repaired using the composite of the same kind or a microhybrid composite. Materials and methods: Nanohybrid (Tetric EvoCeram—TE) and nanofilled (Filtek Supreme—FS) RBC blocks (5 × 5 × 6mm) (N = 128) were fabricated and randomly divided into two groups: (a) no ageing (control group) and (b) ageing (5.000 thermocycling, 5-55°C). RBC surfaces were polished by up to 1,200-grit silicone carbide papers and conditioned with either (a) air abrasion with 30-μm SiO2 particles (CoJet Sand) for 4s + silane coupling agent (ESPE-Sil) + adhesive resin (VisioBond) (n = 16) or (b) adhesive application only (Multilink A+B for TE; Adper ScotchBond 1XT for FS) (n = 16). In half of the groups, repair resin of the same kind with the RBC and, in the other half, a different kind of composite (microhybrid, Quadrant Anterior Shine—AS) with its corresponding adhesive (Quadrant UniBond) was used. The specimens were submitted to MTBS test (0.5mm/min). Data were analysed using three-way ANOVA and Tukey's tests. Degree of conversion (DC) of non-aged and aged resin composites (TE, FS) (n = 3 per group) was measured by micro-Raman analyses. Results: RBC type (p = 0.001) and ageing affected the MTBS results significantly (p = 0.001). Surface conditioning type did not show significant difference (p = 0.726), but less number of pre-test failures was experienced with the CoJet system compared to adhesive resin application only. Repair strength on aged TE showed significantly less (p

Objective: To compare stress transmission around implants with abutments made of three different materials using photoelastic, strain gage (SGA) and finite element (FEA) analyses. Methods: Three abutments – UCLA calcinable, cast in Ni-Cr; UCLA calcinable with a Cr-Co cervical collar, overcast with Ni-Cr; and a zirconia abutment – were installed on implants embedded in photoelastic resin. Vertical and oblique loads were applied to the abutments to the photoelastic and SGA analyses. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (a=0.05). The assembly was modeled to FEA simulation. Results: Similar fringe orders were observed in the apical region under vertical load. The greatest fringe orders were observed in the coronal region of the opposite side of load application (contralateral side) under oblique load. By SGA, no statistical difference was observed among the abutments (P=0.061) under vertical load, and no difference was found between tensile and compression sides under oblique load. FEA showed no difference in stress distribution. The oblique load generated the greatest stress values on the contralateral side in the coronal area. Conclusion: Although it was not possible to establish an agreement among the analytical methods tested, different abutment materials did not influence the transmission of stresses around implants.

Objectives Evaluating the bond strength ( σ ) of resin cement systems (RXA – RelyX ARC; RXU – RelyX U100; and PF – Panavia F) to dentin and yttria-stabilized zirconia-based ceramic (YZ – In-Ceram YZ) after different surface treatments and aging. Methods Occlusal dentin of 54 human molars was exposed and conditioned following manufacturers’ instructions. Fifty-four YZ blocks were sintered and divided into two groups according to surface treatment: PA – airborne particle abrasion, and SC – tribochemical silica coating. All treated YZ blocks were cemented to dentin using one of the cement systems (RXA, RXU, and PF) following manufacturers’ recommendations, which includes specific silane agents. Teeth-cement-ceramic blocks were stored in 37 °C distilled water for 24 h before cutting into non-trimming bar-shaped specimens (adhesive area, A = 1 ± 0.1 mm 2 ). Specimens ( n ≥ 12) were assigned to one of the following conditions: N – no storage; W – stored in 37 °C distilled water for 60 days; and TC – thermal cycling (5–55 °C; 10,000 cycles). All specimens were loaded in tension ( F ) to failure using a universal testing machine. The σ ( F / A ) was calculated and data were statistically analyzed using ANOVA and Tukey tests ( α = 0.05). Fracture surfaces were examined to determine the failure mode. Results RXA-SC and PF-PA specimens showed the greatest mean σ values after N (13.9 and 13.0 MPa, respectively) and TC (12.9 and 14.8 MPa, respectively). SC-treated showed greater mean σ values than PA-treated YZ specimens after W. Significance Regardless of the cement used, W and TC did not significantly reduce the σ of SC-treated YZ resin bonded to dentin.

This article aims to associate patient-reported pain intensity in the immediate seven days after dental implant surgery with surgical factors, sex and patient age. The sample was composed of 108 patients from a dental school in southern Brazilian, between 2018 and 2020. The variables torque, pre- and postoperative medication, healing of first and second intention, gender, age, number of quadrants, number of implants and type of surgery were related to the outcome pain. Pain was reported every day by the patient until the seventh day after surgery, using a visual analogic scale (VAS). Univariate Poisson regression models were used to assess the relationship among pain and the factors. Rate ratios were obtained with 95% of confidence intervals. Overall pain was reported as moderate/intense (VAS: 3-10) by 30.56% of patients, mild pain (VAS: 1-3) by 55.56%, and no pain symptoms were reported by 13.89% of patients. Individuals which the implants were installed with high torques (50-80 N) showed more pain (p=0.03) compared to patients which the implants were installed with regular torque (30-45 N). The other factors evaluated were not significant. The torque was the most relevant factor related to pain among the evaluated by the study. High torque generates more postoperative pain than lower torque. The factors gender, age, number of operated quadrants, number of installed implants, type of surgery and pre and postoperative analgesic did not interfere in the patient's pain during the first week after surgery.