Study of thermocycling effect on the bond strength between an aluminous ceramic and a resin cement

This study evaluated the effect of thermocycling on the bond strength between Procera AllCeram (Nobel-Biocare) and a resin cement (Panavia F, Kuraray CO). Nine ceramic blocks with dimensions of 5x6x6mm were conditioned at one face with Rocatec System (Espe). After, they were luted with Panavia F to composite resin blocks (Clearfil AP-X, Kuraray CO). The nine groups formed by ceramic, cement and composite resin were split up obtaining 75 samples with dimensions of 12x1x1mm and adhesive surface presenting 1mm2±0.1mm2 of area. The samples were divided into 3 groups (n=25): G1 - 14 days in distilled water at 37ºC; G2 – 6,000 cycles in water (5ºC - 55ºC – 30s); G3 – 12,000 cycles in water (5ºC - 55ºC – 30s). The samples were tested in a universal testing machine (EMIC) at a crosshead speed of 1mm/min. Data were analyzed by ANOVA and Tukey tests. The results indicated that mean values of rupture tension (MPa) of G1 (10.71 ± 3.54) did not differ statistically (p <5%) from G2 (9.01 ± 3.90), however there was statistical difference between G1 and G3 (7.28 ± 3.00). It was concluded that thermocycling significantly reduced the bond strength values when samples were submitted to 12,000 cycles.

Root canal filling: fracture strength of fiber-reinforced composite-restored roots and finite element analysis

The aims of this study were to evaluate the effect of root canal filling techniques on root fracture resistance and to analyze, by finite element analysis (FEA), the expansion of the endodontic sealer in two different root canal techniques. Thirty single-rooted human teeth were instrumented with rotary files to a standardized working length of 14 mm. The specimens were embedded in acrylic resin using plastic cylinders as molds, and allocated into 3 groups (n=10): G(lateral) - lateral condensation; G(single-cone) - single cone; G(tagger) - Tagger's hybrid technique. The root canals were prepared to a length of 11 mm with the #3 preparation bur of a tapered glass fiber-reinforced composite post system. All roots received glass fiber posts, which were adhesively cemented and a composite resin core was built. All groups were subjected to a fracture strength test (1 mm/min, 45°). Data were analyzed statistically by one-way ANOVA with a significance level of 5%. FEA was performed using two models: one simulated lateral condensation and Tagger's hybrid technique, and the other one simulated the single-cone technique. The second model was designed with an amount of gutta-percha two times smaller and a sealer layer two times thicker than the first model. The results were analyzed using von Mises stress criteria. One-way ANOVA indicated that the root canal filling technique affected the fracture strength (p=0.004). The G(lateral) and G(tagger) produced similar fracture strength values, while G(single-cone) showed the lowest values. The FEA showed that the single-cone model generated higher stress in the root canal walls. Sealer thickness seems to influence the fracture strength of restored endodontically treated teeth.

Adesivos multi-uso-avaliação da resistência adesiva a dentina frente a teste de cisalhamento, estereomicroscopia e microscopia eletrônica de varredura

Recent bonding systems have been advocated as multi-purpose bonding agents. The aim of this study was to determine if some of these bonding systems could be associated to composite resins from different manufacturers. This investigation was conducted to test lhe shear bond strength of three bonding systems: Scotchbond Multi-Purpose (3M Dental Products), Optibond Light Cure (Kerr) and Optibond Dual Cure (Kerr), when each of them was associated to lhe composite resins: Z1 00 (3M Dental Products), Prisma - APH (Dentsply) and Herculite XRV (Kerr). Seventy-two flat dentin bonding sites were prepared to 600 grit on human premolars mounted using acrilic resins. The teeth were assigned at random to 9 groups of 8 samples each. A split die with a 3mm diameter was placed over lhe surface of lhe dentin treated with one of lhe adhesive systems, and lhe selected composite resin was inserted and light cured. The split mold was removed and all samples were termocycled and stored in 37ºC water for 24 hours before testing. Shear bond strength was determined using an lnstron Universal testing machine. Some failures were examined under lhe S.E.M. Data was analysed by one-way analysis of variance, that demonstrated a significant difference (p<0,05) in the mean shear bond strength among Optibond Light Cure (15,446 MPa), Scotchbond Multi-Purpose (13,339 MPa) and Optibond Dual Cure (10,019 MPa). These values did not depend on the composite resin used. The association between bonding system/composite resin was statistycally significant (p<0,05) and the best results were obtained when the composite resins Z100 and Herculite were used with the adhesive system Optibond Light Cure, and when the composite resin APH was used with the adhesive system Scotchbond Multi-Purpose

Comportamento do esmalte de dentes decíduos após desafio desmineralizante em função de materiais restauradores: estudo ao microscópio de luz polarizada

Pós-graduação em Biopatologia Bucal - ICT

Avaliação do selamento de ápices radiculares retrobturados ou recobertos com diferentes materiais mediante infiltração marginal por corante e análise da interface em microscopia eletrônica de varredura

The purpose of this study was to evaluate the apical sealing ability and the marginal adaptation of five dental materials used in retrofillings or applied to the bevelled root surface. One hundred and forty extracted single rooted human teeth were used, divided into seven groups of twenty each. ln the first, second, third and fourth groups, the teeth were apicoectomized, submitted to cavity preparations and retrofilled with one of the following materiais: zinc free silver amalgam, a dentin bonding system plus composite resin, a glass ionomer cement ora compomer. In the fifth, sixth and seventh groups, the teeth were apicoectomized and capped on the bevelled root surface with one of the following materiais: a dentin bonding system plus composite resin, a glass ionomer cement or a compomer. Two specimens of each experimental group were evaluated for the marginal adaptation using scanning electron microscopy. The remaining 126 specimens were immersed in 2% methylene blue dye, stored for one week at 37ºC and the infiltration was evaluated with a stereomicroscope. The results showed that the glass ionomer cement presented the lowest values of marginal infiltration when used as retrofilling material, with a significant statistical difference when compared with the others tested materials. When used as apical capping, the glass ionomer cement and the compomer were equivalent and significantly better than the dentin bonding system plus composite resin. Using scanning electron microscopy, all the materials showed some slight adjustment problem. ln the retrofilling, the smallest marginal gaps were observed with the compomer and the dentin bonding system plus composite resin, while the largest were observed with the glass ionomer cement and zinc free silver amalgam. ln the apical capping, the smallest marginal gaps were observed with the compomer and the dentin bonding system plus composite resin and ...

Pré tratamento dentinário influência do condicionamento ácido, irradiação laser e hipermineralização na resistência ao cisalhamento de sistema adesivo multi uso

The disadvantages generated by the acid etching of the dentin, such as an increase in its permeability, in the surface moisture and in the potential to denature the external dentinal collagen, the formation of a fragility zone and the citotoxicity of the adhesive monomers; which are all aggravated by the depth of the dentin, have stimulated new and different treatment philosophies of the dentin. The purpose of the present study, therefore, was to investigate the effects of three dentin treatments: laser irradiation, acid etching and hypermineralization, in the shear bond strength of the SMP Plus bonding system. Sixty bovine incisors were extracted and randomly selected immediatly alter the animal's death. They were kept frozen (-18°C) for no longer than 14 days. After buccal dentinal surface had been exposed, X-Rays were taken to control the dentin thickness. The specimens were separated into two groups: (1) Control, kept in distilled water at 4ºC; (2) Mineralized, kept in hypermineralized solution at 4°C for 14 days. Each group was divided into three sub-groups according to the type of dentin treatment used: group F - followed the manufacturer instructions (acid-etching + primer + bond), group AL (acid-etching + primer + bond + laser) and group LA (laser + (laser + acid-etching + primer + bond). A composite resin standard cylinder (Z100-3M) was bond to the dentinal surface and the shear bond strength performed on a Universal lnstron machine 4301, with 500 Kg load and at 0,5mm/min. speed. The analysis of variance (ANOVA) determined that the treatments influenced the shear bond strength values (p<0,05) with the following average shearing load at failure: AL (9,96 MPa), F (7,28MPa) e LA (4,87 MPa). The interaction between the two factors analyzed Group (control and mineralized) and treatment (F, AL, LA) also influenced the shear bond strength (p<0,05). The highest values were obtained...

Reação do tecido conjuntivo subcutâneo de ratos ao implante de Artglass®: estudo histológico

Indirect composite resin systems have been routinely recommended for making restorations in distressed patients. The purpose of this study was to evaluate histologically in rats the effect of chronic stress on the reaction of subcutaneous connective tissue after implant of Artglass™. For this purpose, 60 rats were divided into four groups (GI (control), GII (stressed), GIII (Artglass™) and GIV (Artglass™. / stressed) received dorsal subcutaneous implants of polyethylene tubes containing saline solution (GI and GII) or Artglass™ (GIII and GIV). In groups of four animals were sacrificed at 7,14 and 28 days postoperatively. The results allowed to observe more intense inflammatory reaction and tissue organization later in the animals subjected to stress.

Alteração cromática de resinas compostas laboratoriais submetidas à imersão em diferentes soluções

The pigmentation of indirect composite resins has been one of the most common reasons that lead the restorative treatment to failure. The purpose of this study was to investigate the effect of different solutions on color stability of indirect composite resins. Five brands of indirect composite resins were tested: Adoro, Resilab, Cristobal, Sinfony and Epricord. The samples were immerged in eleven solutions (n=10): common liquid foods (coke soft drink, red wine, coffee and orange juice), mounthrinses (Listerine, Oral-B, Colgate Plax and Periogard) and bleaching agents (carbamide peroxide 16%, 7.5% and hydrogen peroxide 38%) and artificial saliva (control group). The color was measured by a spectrophotometer before and after 7, 14 and 21 days of immersion in common liquid foods, after 12, 24, 36 and 60 hours of immersion in mounthrinses and after 7 and 14 days of immersion in bleaching agents. The Cristobal and Adoro resins showed highest values of ΔE statistically significant compared to the others resin brands. Adoro’s ΔE values changed significantly after the immersion process in red wine and coffee and also between periods measured. The resins Cristobal and Sinfony showed the highest values of ΔE after the immersion process in Listerine with difference statistically significant in comparison to control group. Besides, there was difference statistically significant of the ΔE values  for  Cristobal  after  immersion  in hydrogen peroxide 7,5% in comparison to control group. It can be conclude that all the solutions promoted color change on the indirect composite resins. However, ΔE values  are  whitin  the  values clinically acceptable.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Restauração transcirúrgica como alternativa na resolução das perfurações endodônticas

The endodontic perforations are iatrogenic communications that result in a communication between the endodonto and periodontium. This occurrence represents about 10 % of cas- es of failure in endodontic treatment. The management may vary and is related to the drilling site endodontic. This paper aims to report a case of iatrogenic perforation and one of the possible alternatives for the treatment of endodontic perforations -level cervical tooth. During the opening coronary perforation occurred due to improper slope cervical penetration drill. Considering the drilling site, we opted for sealing com- posite resin after surgical access and absolute isolation. After sealing, the channel was filled with medication and instru- mented based on calcium hydroxide. Later the canal was obturated by lateral condensation technique with Sealapex. The radiographic follow-up showed regression of the lesion and the clinical silence confirmed the success of the treatment.

Evaluation in situ of tag formation in dental enamel submitted to microabrasion technique: effect of two etching times

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Emprego de técnica cirúrgica e materiais adesivos diretos no fechamento de diastema

The following is a clinical case report of a patient whose main complaint was the presence of a generalized spacing in the anterior maxillary segment. After meticulous clinical analysis and discussions of the clinical procedures to be adopted, a labial frenectomy was our first choice, so that we could reduce the diastemas directly using composite resin. It was observed that the association of clinical and restorative procedures was capable of giving back shape, function and dental aesthetics, allowing to the young patient the satisfaction of smiling without any fear.

Diastemas: reestablishment of an attractive smile

A healthy and attractive smile is very valued in today s society. Yet this requires better aesthetic and cosmetic solutions from dental surgeons.The present paper presents a case report of diastema closure using an association of tooth movement induced by orthodontic elastics,dental cosmetics and resin-bonded prosthesis. The female patient L.B.A.J., aged 19 years, visited the Integrated Clinic of Araçatuba DentalSchool UNESP mainly complaining of missing teeth and poor esthetics. After anamnesis, clinical and radiographic examination revealedhypodontia of the maxillary right and left first premolars, abnormal maxillary right lateral incisor shape and diastema between the maxillaryright lateral incisor and canine and between the maxillary left lateral incisor and canine. Planning was done which included indication ofdiastema closure with composite resin restoration and metal-free resin-bonded prosthesis, with a structure made of Vectris (Ivoclar VivadentInc., Amherst, NT, USA). The option for dental cosmetics associated with resin-bonded prosthesis after movement with orthodontic elasticsresulted in an excellent aesthetic outcome of low cost and short treatment duration.Indexing terms: composite resins; diastema; fixed resin bonded partial denture.

Avaliação da resistência de união de reparos em resinas compostas convencionais e bulkfill

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)