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Purpose: The present study aimed to evaluate which of the following imaging methods best assessed misfit at the tooth-restoration interface: (1) bitewing radiographs, both conventional and digital, performed using a photostimulable phosphor plate (PSP) and a charge-coupled device (CCD) system; (2) panoramic radiographs, both conventional and digital; and (3) cone-beam computed tomography (CBCT)., Materials and Methods: Forty healthy human molars with class I cavities were selected and divided into 4 groups according to the restoration that was applied: composite resin, composite resin with liner material to simulate misfit, dental amalgam, and dental amalgam with liner material to simulate misfit. Radiography and tomography were performed using the various imaging methods, and the resulting images were analyzed by 2 calibrated radiologists. The true presence or absence of misfit corresponding to an area of radiolucency in regions subjacent to the esthetic and metal restorations was validated with microscopy. The data were analyzed using a receiver operating characteristic (ROC) curve, and the scores were compared using the Cohen kappa coefficient., Results: For bitewing images, the digital systems (CCD and PSP) showed a higher area under the ROC curve (AUROC) for the evaluation of resin restorations, while the conventional images exhibited a larger AUROC for the evaluation of amalgam restorations. Conventional and digital panoramic radiographs did not yield good results for the evaluation of resin and amalgam restorations ( P <.05). CBCT images exhibited good results for resin restorations ( P >.05), but showed no discriminatory ability for amalgam restorations ( P <.05)., Conclusion: Bitewing radiographs (conventional or digital) should be the method of choice when assessing dental restoration misfit.

Purpose: Misfit is a risk factor for rehabilitation with implants, and its detection is of fundamental importance to the success of treatment with implants. The use of appropriate radiographic imaging is key for a good prognosis. The aim of this study was to compare the efficacy of film and digital radiographs for the detection of misfit at the implant-abutment interface., Materials and Methods: Digital and conventional (manual and automatic processing) radiography was performed in seven test specimens, each one with a different vertical misfit between the abutment and the platform of the implant. Scanning electron microscopy was used to confirm the misfit and to measure it. Five dental radiologists independently and blindly evaluated the images. Cohen's kappa with linear weighting was calculated to determine interexaminer and intraexaminer concordance. Statistical analyses were performed using the Cochran's Q test and the receiver operating characteristic curve (ROC)., Results: Interexaminer analysis showed that the kappa value was equal to 0.74, whereas the average kappa value in the intraexaminer evaluation was 0.90. Digital imaging showed the largest area on the ROC graph, and conventional images with manual processing showed the smallest area. The images obtained through conventional radiography with both manual and automatic processing showed statistically significant differences from the measurement of the gold standard (P < .05)., Conclusion: Digital imaging can be used to evaluate misfit at the implant-abutment interface. Conventional systems of radiographic imaging do not provide sufficient information to evaluate misfit at the implant-abutment interface.

This study evaluated the effects of the remaining coronal tissue and post type on the fracture strength of incisors. Sixty human maxillary central incisors were sectioned at the cemento-enamel junction or at 2 mm above this junction. The roots received cast cores and posts, fibre posts, or relined fibre posts (n = 10 each). A compressive load was applied over the cores untilfracture. In the absence of coronal structure, the fracture strength did not differ among the post types evaluated. In the presence of remaining coronal structure, the fracture strength was higher in specimens with cast cores and posts.

The objective of this study was to test the effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cement (RMGIC). One hundred premolars, extracted for orthodontic reasons, were divided into five groups (n = 20). Group 1 (control): enamel was etched with 35 per cent phosphoric acid, a thin layer of adhesive was applied, and the brackets were bonded with Transbond XT. Group 2: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with conventional glass ionomer cement (GIC). Group 3: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with conventional GIC. Group 4: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with RMGIC. Group 5: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with RMGIC. The teeth were stored in distilled water for 24 hours before they were submitted to shear testing. The results demonstrated that bond strength values of group 1 (17.08 ± 6.39 MPa) were significantly higher in comparison with the other groups. Groups 2 (3.43 ± 1.94 MPa) and 3 (3.92 ± 1.57 MPa) presented values below the average recommended in the literature. With regard to adhesive remnant index, the groups in which the enamel was treated with NaOCl showed a behaviour similar to that of the resin composite. It is conclude with enamel treatment with NaOCl increased bonding strength of brackets bonded with GIC and RMGIC, but increased bond strength was not statistically significant when compared to the untreated groups.

Objectives: The concept of vertical dimension of occlusion (VDO) refers to a measure in the vertical plane that establishes the relation between the maxilla and the mandible when the posterior teeth, both from the maxillary and from the mandibular arches, are occluded, regardless of whether they are natural or prosthetic, healthy or restored. This measure is subject to change, and when this occurs, it can compromise both the function and the facial aesthetics. This study proposed to develop a methodology based on cephalometric analysis by studying the 31 lateral teleradiographs of adult, dentate individuals to determine the VDO, based on bone structures that are not dependent on the presence or absence of posterior teeth. The final goal was to make this application accessible to individuals who have undergone alterations of the lower portion of the face., Materials and Methods: The cephalometric analysis of this study, called Seraidarian-Tavano, was verified through facial angles (upper and middle angles) that, when correlated, determine the lower position of the face., Results: The analysis of results showed that no statistically significant difference between the angles studied could be observed (superior angle 50.29 ± 3.35 e median angle 49.95 ± 3.37). In the same manner, no variation in the results regarding gender in the measure of these angles could be observed., Conclusion: This cephalometric analysis can be applied to determine the VDO, regardless of the presence or absence of posterior teeth., (© 2011 The Gerodontology Society and John Wiley & Sons A/S.)

Objectives: In some clinical situations, dentists come across partially edentulous patients, and it might be necessary to connect teeth to implants. The aim of this study was to evaluate a metal-ceramic fixed tooth/implant-supported denture with a straight segment, located in the posterior region of the maxilla, when varying the number of teeth used as abutments., Material and Methods: A three-element fixed denture composed of one tooth and one implant (Model 1), and a four-element fixed denture composed of two teeth and one implant (Model 2) were modeled. A 100 N load was applied, distributed uniformly on the entire set, simulating functional mastication, for further analysis of the SEQV (Von Mises) principal stresses, which were compared with the flow limit of the materials., Results: In a quantitative analysis, it may be observed that in the denture with one tooth, the maximum SEQV stress was 47.84 MPa, whereas for the denture with two teeth the maximum SEQV stress was 35.82 MPa, both located in the region between the pontic and the tooth., Conclusion: Lower stresses were observed in the denture with an additional tooth. Based on the flow limit of the materials, porcelain showed values below the limit of functional mastication.

Objectives: This study evaluated by three-dimensional finite element analysis the tensions generated by different disocclusion patterns (canine guide and bilateral balanced occlusion) in an implant-supported mandibular complete denture., Material and Methods: A three-dimensional model of implant-supported mandibular complete denture was fabricated according to the Brånemark protocol. A 5-element 3.75 x 13-mm screw-shape dental implant system was modeled for this study. The implants were located in the inter-mental foramen region with 3-mm-high prosthetic components joined by a nickel-chromium framework with 12-mm bilateral cantilever covered by acrylic resin and 12 acrylic denture teeth. SolidWorks software was used before and after processing the simulations. The mechanical properties of the components were inserted in the model and a 15 N load was established in fixed points, in each one of the simulations. Data were collected in the entire nickel-chromium framework. The results were displayed three-dimensionally as color graphic scales., Results: The canine guide generated greater tensions in the region of the first implant, while the bilateral balanced occlusion generated great tensions in the entire metallic framework. The maximum tension found in the simulation of the bilateral balanced occlusion was 3.22 fold higher than the one found in the simulation of the disocclusion in canine guide., Conclusion: The pattern of disocclusion in canine guide is the ideal for implant-supported mandibular complete denture.

A comparative and qualitative analysis of the tensions generated in the cantilever region of an implant-supported mandibular complete denture was conducted using the three-dimensional finite element method. The mechanical properties of the components were input in the model and a load of 15 N was applied in pre-determined points. In the first simulation, the load was applied on the occlusal surface of the first premolar. In the second simulation, it was applied on the first and second premolars. In the third simulation, it was applied on the first and second premolars and on the first molar. The different occlusion patterns produced similar tension distributions in the cantilever region, which followed a similar pattern in the three simulations. In all of the cases, the highest levels of tension were located in the region of the first implant. However, as the loads were dislocated distally, the tensions increased considerably. The more extensive the cantilever, the more compromised will be the infrastructure, the prosthetic components and the implants. Regardless of the length of the cantilever, the highest tensions will always be located in the region of the implant next to the load application point.

Aiming to assess the effect of mixing process on microleakage, 40 primary molars were filled with encapsulated glass ionomer cements (GICs) (Vidrion, RCaps and Fuji, IXGPFAST) or with GICs stored in bottles (Vidrion, R and Fuji, IX). Dye penetration was assessed using scores. Encapsulation and mechanical mixing have reduced significantly marginal microleakage levels in class II restorations performed with conventional GICs if compared to the values obtained by their bottled correspondents (p=0.000).

With the aim of assessing the performance of Brazilian and imported glass ionomer cements (GIC) with regard to microleakage, 40 primary molars received two standard class II cavity preparations with margins in enamel. Twenty cavities were filled with Brazilian materials (Vidrion R and Vidrion R(Caps)) and the other 20 cavities were filled with imported materials (Fuji IX and Fuji IX(GPFast) capsule). All fillings were performed by a single operator according to the manufacturer's instructions. Teeth were immersed in 0.5% methylene blue and half-sectioned. Three independent calibrated examiners assessed microleakage using scores (0-3). Data were submitted to the Kruskal-Wallis statistical test and Wilcoxon analysis. High microleakage indexes were verified for all ionomer cements: 59.5% of the samples restored with Vidrion R or Vidrion R(Caps) and 83.4% of the samples restored with Fuji IX or Fuji IX(GPFast) capsule obtained the maximum score (3). The Brazilian ionomer cements presented less microleakage than imported cements, although this difference was only significant (p=0.003) among the encapsulated materials.

The purpose of this study was to evaluate the correlation between degree of conversion and microhardness in dental composites, as well as the effect of the inorganic content and type of photo-curing unit on these parameters. Three indirect composites (Artglass, Solidex and Zeta LC) were polymerized by means of three different laboratorial units (UniXS, Solidilite and an experimental device). For each material, fifteen samples were prepared using a metal matrix. The degree of conversion was analyzed by means of infrared spectroscopy, and microhardness was also assessed. The inorganic content was measured by means of thermogravimetric analysis (TGA). The Pearson s test was carried out in order to determine correlations. The degree of conversion of Artglass ranged from 37.5% to 79.2%, and its microhardness, from 32.4 to 50.3 (r = 0.904). The degree of conversion of Solidex ranged from 41.2% to 60.4%, and its microhardness, from 33.3 to 44.1 (r = 0.707). The degree of conversion and the microhardness of Zeta LC ranged from 62.0% to 78.0% and from 22.6 to 33.6, respectively (r = 0.710). It was concluded that the utilization of different photo-curing units caused variations on the degree of conversion, as a result of specific characteristics of each unit. For each material, there was strong correlation between the degree of conversion and microhardness. In addition, when different materials were compared, microhardness was more affected by filler content than by the degree of conversion.

Ninety-five patients with syndrome X were studied by brain single-photon emission computed tomographic examination; 72 (76%) had pathologic findings suggestive of cerebral perfusion abnormalities. These findings support the hypothesis of a vascular disorder not confined to cardiac vessels.