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Purpose: The aim of this study was to verify quality of life related to oral health and satisfaction with dentures. Conventional mandibular complete dentures were converted to overdentures retained by two implants with immediate loading (bar-clip system, n = 16). Materials and Methods: The Brazilian short version of the Oral Health Impact Profile (OHIP-14Br) was used to evaluate the impact of oral health on quality of life. Satisfaction with the prostheses was obtained by means of a questionnaire addressing satisfaction with the present prostheses and through use of a visual analog scale (VAS). Results: The results of the OHIP-14Br questionnaire were verified at 3 and 6 months after conversion from complete dentures to a mandibular overdenture. The satisfaction questionnaire for the mandibular prostheses obtained 43.75% satisfaction before conversion and 100% satisfaction at 1 week and 3 and 6 months after conversion. The satisfaction results of the prostheses, both maxillary and mandibular, were 68.75% before conversion, 93.75% at 1 week and 3 months after conversion, and 87.5% at 6 months. There was an immediate improvement in patients' satisfaction with the mandibular overdenture prostheses regarding stability and retention (Friedman test, P = .000) and quality of life (Friedman test, P = .001). Conclusion: The improvement seen justifies the immediate loading approach used in this study. Int J Prosthodont 2011;24:534-539. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the peri-implant stress fields generated from four different implant-abutment interfaces under axial loading applied at the center of the implant and several millimeters away from the implant center via photoelastic analysis. Materials and Methods: Similar unthreaded and cylindric implants and abutments were fabricated and embedded in photoelastic resin with four different implant-abutment interfaces: external hex, internal hex, internal taper (11.5 degrees), and solid connection to the abutment (one piece). The samples were submitted to vertical compressive loads; one was applied at the implant center (1.5 kg; centered load), and the other was applied 6.5 mm away from the center, 4.4 mm from the outside of the outer aspect of the implant (0.75 kg; off-centered load). The maximum shear stresses were determined and observed at 46 points around the implants under the centered load and at 61 points under the off-center load in the photoelastic models. Graphics describing the maximum shear stress (y-axis) and the analyzed points (x-axis) were obtained, and areas under the curves were calculated. Results: The centered loading (all points) resulted in small differences. The lowest amounts of stress were observed for the internal-taper implants, and values were minimally greater (0.4% to 3.3%) for the other implants. No statistically significant differences were found between groups for the centered load in any area. Under an off-center load, the internal-hex implants presented the least stress (all points). For off-center loading, the internal-hexagon implants differed significantly from the external-hex and one-piece implants and displayed the lowest stress levels. Conclusion: Under an off-center load, the internal-hex interfaces presented the lowest stress concentrations, internal-taper interfaces presented intermediate results, and one-piece and external-hex implants resulted in high stress levels. Centralized axial loads produced similar results. [ABSTRACT FROM AUTHOR]

PURPOSE: The purpose of this study was to consider the therapeutic decision whether to use advanced surgery or short implants based on data concerning the use of these implants found in follow-up studies. MATERIALS AND METHODS: The MEDLINE database was consulted for follow-up studies published between the years 1980 and 2004. For those studies that met the inclusion and exclusion criteria, data concerning the number of implants 7, 8.5, or 10 mm long placed and lost, the time at which the failure occurred, and related risk factors were gathered for 33 studies arranged in tables and subjected to analysis. The studies included 16,344 implant placements with 786 failures (4.8%). Implants were analyzed according to the time of failure (i.e., before or after prosthesis seating) and risk factors implicated in the failures. RESULTS: The total rate of failures was 4.8%. Implants 3.75 mm wide and 7 mm long failed at a rate of 9.7%, compared to 6.3% for 3.75 x 10-mm implants. It was found that 54.9% of failures occurred before the prosthesis connection. Finally, 66.7% of all failures were attributed to poor bone quality, 45.4% to the location (maxilla or mandible), 27.2% to occlusal overload, 24.2% to location within the jaw, and 15.1% to infections (an implant could be associated with multiple risk factors). DISCUSSION: The analysis revealed that among the risk factors, poor bone quality in association with short implants seemed to be relevant to failure. The use of implants 4 mm in diameter appeared to minimize failure in these situations. The 3.75 x 7-mm implant presented the highest failure rate (9.7%) of 1894 implants analyzed (excluding implant designs with higher failure rates but few total implants). CONCLUSION: Short implants should be considered as an alternative to advanced bone augmentation surgeries, since surgeries can involve higher morbidity, require extended clinical periods, and involve higher costs to the patient. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate and compare the accuracy of conventional and 3D-printed casts using five different 3D printers., Materials and Methods: In the control group (CG group, n = 5), five conventional impressions using light- and heavy-body polyvinyl siloxane were obtained from the master model, resulting in five stone models. In the test groups, five different scans were performed by a well-trained and experienced clinician using a TRIOS intraoral scanner. All data were exported in STL file format, processed, and sent to five 3D printers. Five casts were manufactured in each printer group: SG (CARES P20, Straumann); FG (Form 2, Formlabs); WG (Duplicator 7, Wanhao); ZG (Zenith D, Zenith); and MG (Moonray S100, Moonray). Measurements of the accuracy (trueness and precision) of the casts obtained from conventional elastomeric impressions and 3D-printing methods were accomplished using a 3D analysis software (Geomagic Control)., Results: The FG group showed the lowest values for trueness (indicating a value closer to real dimensions), which were similar to the SG group only (P > .05). MG, WG, and ZG groups presented higher values and were similar compared to each other. Data on precision demonstrated that all 3D-printed groups showed lower values for precision (smaller deviation) when compared to the CG., Conclusions: The trueness depends on the chosen 3D printer. All of the tested 3D printers were more precise than cast models obtained from conventional elastomeric impressions.

Objectives: This in vitro comparative study aimed to evaluate the physical and mechanical properties of four 3D-printed resins with two different thickness layers., Methods: Four printed resins (VarseoSmile Crown Plus, VSC; NexDent C&B MFH, MFH; Nanolab 3D, NNL; and Resilab 3D Temp, RSL) were printed with 50 µm and 100 µm layer thickness, resulting in 80 bars measuring 25 × 2×2 mm. The specimens underwent a Raman spectroscopy for degree of conversion, confocal laser scanning microscopy for surface roughness (Sa), three-point bending test for flexural strength and elastic modulus, and a Vickers hardness test (VHN). Data was tested for normality using the Shapiro-Wilk, two-way ANOVA, and Tukey test (α = 0.05) for statistical analysis., Results: The layer thickness affected all performed tests, but the elastic modulus (p < 0.001). Specimens with 100 µm showed, in general, worse results outcomes than those with 50 µm (p < 0.001). However, within the limitations of this comparative in vitro study, it could be concluded that the tested resins and layer thicknesses directly influenced physical and mechanical properties., Significance: The physical and mechanical properties of three-dimensional printed restorations can be affected by the layer thickness, which can interfere with the choice of the 3D printing resin for a desired clinical outcome., (Copyright © 2023 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)

Purpose: This study evaluated the microleakage at different implant-abutment (I-A) connections under unloaded and loaded conditions., Materials and Methods: Forty implants, specially designed with an opening at the apex, were grouped according to the I-A and screw device: external hexagon implants with titanium (EH) or EH diamond-like carbon screws fixing the abutment; internal hexagon implants with titanium screws (IH); and Morse taper implants with solid (MT) or MT passing screws (MTps) abutments. The implants were fixed in a 2-compartment device, and toluidine blue solution (1.0 mg/mL) was placed at the I-A interface (upper compartment). The lower compartment was filled with purified water. Four implants of each group were loaded (50 N, 1.2 Hz) and after 50,000, 100,000, 200,000, and 300,000 cycles, aliquots were collected from the lower compartment for absorbance reading. Data were analyzed using analysis of variance for repeated measurements and Tukey (α = 0.05)., Results: Although microleakage increased over time in most of the groups, MTps group showed lower values when loaded (P < 0.05). The DLC on the EH screw did not prevent microleakage (P < 0.05)., Conclusion: It can be concluded that MT connection is more effective to prevent microleakage.

Purpose: The aim of this study was to evaluate the effectiveness of fabrication methods (computer-aided design/computer-aided manufacture [CAD/CAM], copy-milling, and conventional casting) in the fit accuracy of three-unit, screw-retained fixed dental prostheses., Materials and Methods: Sixteen three-unit implant-supported screw-retained frameworks were fabricated to fit an in vitro model. Eight frameworks were fabricated using the CAD/CAM system, four in zirconia and four in cobalt-chromium. Four zirconia frameworks were fabricated using the copy-milled system, and four were cast in cobalt-chromium using conventional casting with premachined abutments. The vertical and horizontal misfit at the implant-framework interface was measured using scanning electron microscopy at ×250. The results for vertical misfit were analyzed using Kruskal-Wallis and Mann-Whitney tests. The horizontal misfits were categorized as underextended, equally extended, or overextended. Statistical analysis established differences between groups according to the chi-square test (α = .05)., Results: The mean vertical misfit was 5.9 ± 3.6 μm for CAD/CAM-fabricated zirconia, 1.2 ± 2.2 μm for CAD/CAM-fabricated cobalt-chromium frameworks, 7.6 ± 9.2 μm for copy-milling-fabricated zirconia frameworks, and 11.8 (9.8) μm for conventionally fabricated frameworks. The Mann-Whitney test revealed significant differences between all but the zirconia-fabricated frameworks. A significant association was observed between the horizontal misfits and the fabrication method. The percentage of horizontal misfits that were underextended and overextended was higher in milled zirconia (83.3%), CAD/CAM cobaltchromium (66.7%), cast cobalt-chromium (58.3%), and CAD/CAM zirconia (33.3%) frameworks., Conclusion: CAD/CAM-fabricated frameworks exhibit better vertical misfit and low variability compared with copy-milled and conventionally fabricated frameworks. The percentage of interfaces equally extended was higher when CAD/CAM and zirconia were used.

Objective: To evaluate the behavior of C-reactive protein (CRP) levels in the first three weeks after total knee arthroplasty (TKA) and define the factors related to its variation., Methods: We evaluated the CRP values in 103 patients undergoing primary TKA. Serum CRP was measured on the day before surgery, and on the third and twenty-first days after the procedure., Results: PCR showed sudden increase on the third day after surgery, reaching the mean value of 111.9 mg/L, median 75.9 mg/L. Only one-third of the patients returned to normal levels in the third week. In the immediate postoperative period, CRP was not correlated with body mass index (BMI), age, gender, blood transfusion, or complications., Conclusion: Serum CRP remains high in the third week after TKA in most patients, and this change is primarily related to surgical trauma.

Countercurrent chromatography (CCC) is being widely used across the world for purification of various materials, especially in natural product research. The predictability of CCC scale-up has been successfully demonstrated using specially designed instruments of the same manufacturer. The reality is that the most of CCC users do not have access to such instruments and do not have enough experience to transfer methods from one CCC column to another. This unique study of three international teams is based on innovative approach to simplify the scale-up between different CCC machines using fractionation of Schinus terebinthifolius berries dichloromethane extract as a case study. The optimized separation methodology, recently developed by the authors (Part I), was repeatedly performed on CCC columns of different design available at most research laboratories across the world. Hexane - ethyl acetate - methanol - water (6:1:6:1, v/v/v/v) was used as solvent system with masticadienonic and 3β-masticadienolic acids as target compounds to monitor stationary phase retention and calculate peak resolution. It has been demonstrated that volumetric, linear and length scale-up transfer factors based on column characteristics can be directly applied to different i.d., volume and length columns independently on instrument make in an intra-apparatus scale-up and inter-apparatus method transfer., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The aim of this study is to evaluate the effects of replacing poorly fitting dentures on patient's masticatory function, satisfaction and oral health-related quality of life. Fourteen patients with conventional maxillary complete dentures and mandibular overdentures retained by two implants bar clip system had their dentures replaced. The laboratory tests for the analysis of masticatory performance were conducted using an "Optocal" food simulator test. Questionnaires were used to evaluate patient satisfaction with dentures and impact of oral health on quality of life. Tests were conducted and questionnaires were administered before and 1, 3 and 6 months after the patient had adapted to the new dentures. Masticatory performance data and satisfaction with dentures (Visual Analogic Scale) were statistically analyzed by ANOVA and Tukey b test, satisfaction with dentures (SATs P) and impact of oral health on quality of life were evaluated using the Wilcoxon and Friedman tests (a=.05). There was no statistically significant improvement in masticatory function after denture replacement, although better outcomes were observed. Satisfaction with dentures and total score obtained using the OHIPedent showed significant improvement. It can be suggested that the potential for grinding food, patient satisfaction and aspects of quality of life improved immediately after denture replacement., (Sociedad Argentina de Investigación Odontológica.)

Purpose: The aim of this study was to compare the maximum load on the elastic limit of internal conical (IC) implants with regular external hexagon (REH) and narrow external hexagon (NEH) implants., Materials and Methods: Thirty cylindrical implants were divided in 3 groups (n = 10): REH (3.75 mm); NEH (3.3 mm); IC (3.5 mm). The implants were evaluated by means of cantilever bending loads using a mechanical testing machine. A strain qualitative analysis and the corresponding angles were analyzed. Using single factor analysis of variance with Tukey Test and Friedman Test (P < 0.05) the statistical analysis for data were performed., Results: REH (294.37 N) and IC (294.37 N) groups presented statistically greater Fle than NEH (189.16 N). Regarding to the strain, there were no significant differences among groups. However, there were a greater number of fissures and more fractures present on NEH group., Conclusion: The IC implant with smaller diameter did not result in reduction of elastic limit when compared with the REH implants. Nevertheless, the reduction of 0.45 mm of the hexagonal connection implant's diameter has significantly diminished the elastic limit.

Introduction: Regarding implant-supported prostheses, the most reported types of complications are related to loosening or fracturing of abutment or prosthesis screws. This case report shows a series of procedures that allowed a conservative solution for a fractured screw. It avoided removing the implant and also allowed the same prosthesis to be used after guided-drilling the fractured screw and re-tapping the implant internal threads. The same prosthesis was replaced immediately after the procedure., Patient: A 67-year-old male patient, who had a fractured abutment screw of the lower left first molar implant. The patient decided for the conservative treatment option and an attempt was made to remove the fractured screw., Discussion: Parafunctional habits can generate excessive occlusal forces, which are risk factors associated with loosening and fracturing implant screws and even the fixtures themselves. This case report focus on the probable causes, difficulties and risks associated with this procedure and it also discusses the alternative approaches., Conclusion: The purposed treatment allowed a time and money saving resolution for fractured abutment screws., (Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.)

This study sought to assess the effect of different surface finishing and polishing protocols on the surface roughness and bacterial adhesion (S. sanguinis) to polymethyl methacrylates (PMMA). Fifty specimens were divided into 5 groups (n = 10) according to their fabrication method and surface finishing protocol: LP (3 : 1 ratio and laboratory polishing), NF (Nealon technique and finishing), NP (Nealon technique and manual polishing), MF (3 : 1 ratio and manual finishing), and MP (3 : 1 ratio and manual polishing). For each group, five specimens were submitted to bacterial adhesion tests and analyzed by scanning electron microscopy (SEM). Two additional specimens were subjected to surface topography analysis by SEM and the remaining three specimens were subjected to surface roughness measurements. Data were compared by one-way ANOVA. The mean bacterial counts were as follows: NF, 19.6 ± 3.05; MP, 5.36 ± 2.08; NP, 4.96 ± 1.93; MF, 7.36 ± 2.45; and LP, 1.56 ± 0.62 (CFU). The mean surface roughness values were as follows: NF, 3.23 ± 0.15; MP, 0.52 ± 0.05; NP, 0.60 ± 0.08; MF, 2.69 ± 0.12; and LP, 0.07 ± 0.02 (μm). A reduction in the surface roughness was observed to be directly related to a decrease in bacterial adhesion. It was verified that the laboratory processing of PMMA might decrease the surface roughness and consequently the adhesion of S. sanguinis to this material.

This study aims to compare stress transmitted to implants and passive fit of one-piece cast frameworks fabricated with 3 different materials: commercially pure titanium (G1-CP Ti), cobalt-chromium alloy (G2-Co-Cr), and nickel-chromium-titanium alloy (G3-Ni-Cr-Ti). In total, 12 frameworks simulating bars for fixed prosthesis in a model with 5 implants were fabricated. The passive fit of the framework interface was measured using an optical microscope and the stresses transmitted to implants were measured using quantitative photoelastic analysis. Data were statistically analyzed by analysis of variance (ANOVA) and least significant difference (LSD) tests (α = 0.05). Mean and standard deviation values of passive fit and stress over implants are presented, respectively: G1 [472.49 (109.88) μm and 11.38 (9.23) KPa], G2 [584.84 (120.20) μm and 15.83 (9.30) KPa], and G3 [462.70 (179.18) μm and 16.39 (9.51) KPa]. For stress over implants, there were significant differences between G1, G2, and G3 (P = 0.035), being the lowest values for the G1. There were no significant differences for passive fit between G1 and G3 (P = 0.844), but both were statistically different from G2 (P = 0.028 and P = 0.035, respectively), which showed the worse results. It may be concluded that the stress over implants was affected by the tested materials. The CP Ti presented the best values for the evaluated items.

Countercurrent chromatography is a form of liquid-liquid partition chromatography in which the stationary liquid phase is retained in the apparatus without the use of a solid support. Gradient elution in countercurrent chromatography can be used in many different ways, such as linear gradients, stepwise elution gradients, pH gradients, etc. The main goal of using the gradient approach is to shorten the duration of the separation and improve resolution, especially when the retention range of the sample to be purified is broadening and, thus, the compounds cannot be purified by only one solvent system. The principle is based on modifying the mobile phase to increase the elution strength with no or minimum changes in the stationary phase, which can be a difficult task since both phases are in intimate contact all the time. The most common ways to perform gradients in countercurrent chromatography are changing the mobile's phase polarity, flow rate, and pH, what is called linear or step gradient, flow rate gradient, pH gradient, respectively., (Georg Thieme Verlag KG Stuttgart · New York.)

Purpose: To evaluate the influence of Morse taper implant index on microleakage., Materials and Methods: Thirty implants and abutments were divided into 3 groups (n = 10): CM1 (universal post and implant without index), CM2 (universal post and implant with index), and CM3 (abutment and implant with index). To evaluate the microleakage from the implant inner part, the implants were inoculated with Streptococcus sanguinis solution at a 0.5 McFarland and incubated for 7 days at 37°C in Eppendorf tubes with sterile broth. To evaluate the microleakage into the inner part of implant, these were inoculated with sterile Schaedler broth and immersed in a Fusobacterium nucleatum solution at a 0.5 McFarland. The samples were incubated for 30 days in an anaerobic chamber., Results: Nine samples of each group of the first methodology showed no presented bacterial contamination. No samples of the second methodology demonstrated turbidity of the broth., Conclusion: The presence of the prosthetic internal index had no influence on bacterial microleakage of Morse taper implants under static conditions, for both methodologies.

This in vitro study used microcomputed tomography to evaluate the marginal fit of crowns fabricated using a chairside computer-aided design/computer-aided manufacturing (CAD/CAM) system with different methods of virtual model acquisition. Crowns were fabricated to fit in a cast containing a single human premolar. Four methods of virtual model acquisition were used: Group 1 (control), digital impressioning of a typodont; Group 2, digital impressioning of a powdered typodont; Group 3, digital impressioning of a regular impression; and Group 4, digital impressioning of a master cast. Statistically significant differences were found between the marginal gap of Group 2 and the other groups (P < 0.05); no differences were found among Groups 1, 3, and 4. The results showed that crowns fabricated using the chairside CAD/CAM system exhibited significantly smaller vertical misfit when a thin layer of powder was applied over the typodont before digital impressioning.

'Countercurrent chromatography' (CCC) is an ideal technique for the recovery, purification and isolation of bioactive natural products, due to the liquid nature of the stationary phase, process predictability and the possibility of scale-up from analytical to preparative scale. In this work, a method developed for the fractionation of Schinus terebinthifolius Raddi berries dichloromethane extract was thoroughly optimized to achieve maximal throughput with minimal solvent and time consumption per gram of processed crude extract, using analytical, semi-preparative and preparative 'high performance countercurrent chromatography' (HPCCC) instruments. The method using the biphasic solvent system composed of n-heptane-ethyl acetate-methanol-water (6:1:6:1, v/v/v/v) was volumetrically scaled up to increase sample throughput up to 120 times, while maintaining separation efficiency and time. As a fast and specific detection alternative, the fractions collected from the CCC-separations were injected to an 'atmospheric pressure chemical ionization mass-spectrometer' (APCI-MS/MS) and reconstituted molecular weight MS-chromatograms of the APCI-ionizable compounds from S. terebinthifolius were obtained. This procedure led to the direct isolation of tirucallane type triterpenes such as masticadienonic and 3β-masticadienolic acids. Also oleanonic and moronic acids have been identified for the first time in the species. In summary, this approach can be used for other CCC scale-up processes, enabling MS-target-guided isolation procedures., (Copyright © 2015 Elsevier B.V. All rights reserved.)

For the development of an efficient two-stage isolation process for high-speed countercurrent chromatography (HSCCC) with focus on principal metabolites from the ethyl acetate extract of the halophyte plant Salicornia gaudichaudiana, separation selectivities of two different biphasic solvent systems with similar polarities were evaluated using the elution and extrusion approach. Efficiency in isolation of target compounds is determined by the solvent system selectivity and their chronological use in multiple separation steps. The system n-hexane-ethyl acetate-methanol-water (0.5:6:0.5:6, v/v/v/v) resulted in a comprehensive separation of polyphenolic glycosides. The system n-hexane-n-butanol-water (1:1:2, v/v/v) was less universal but was highly efficient in the fractionation of positional isomers such as di-substituted cinnamic acid quinic acid derivatives. Multiple metabolite detection performed on recovered HSCCC tube fractions was done with rapid mass-spectrometry profiling by sequential off-line injections to electrospray mass-spectrometry (ESI-MS/MS). Selective ion traces of metabolites delivered reconstituted preparative HSCCC runs. Molecular weight distribution of target compounds in single HSCCC tube fractions and MS/MS fragment data were available. Chromatographic areas with strong co-elution effects and fractions of pure recoverable compounds were visualized. In total 11 metabolites have been identified and monitored. Result of this approach was a fast isolation protocol for S. gaudichaudiana metabolites using two solvent systems in a strategic sequence. The process could easily be scaled-up to larger lab-scale or industrial recovery., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Statement of Problem: Relatively little information is available on the accuracy of the abutment-implant interface in computer-aided design and computer-aided manufacturing (CAD/CAM)-fabricated zirconia and cobalt-chromium frameworks., Purpose: The purpose of this study was to compare the fit accuracy of CAD/CAM-fabricated zirconia and cobalt-chromium frameworks and conventionally fabricated cobalt-chromium frameworks., Material and Methods: Four groups of 3-unit, implant-supported, screw-retained frameworks were fabricated to fit an in vitro model with 3 implants. Eight frameworks were fabricated with the CAD/CAM system: 4 in zirconia and 4 in cobalt-chromium. Another 8 were cast in cobalt-chromium with conventional casting, including 4 with premachined abutments and 4 with castable abutments. The vertical misfit at the implant-framework interface was measured with scanning electron microscopy when only 1 screw was tightened and when all screws were tightened. Data were analyzed with the Kruskal-Wallis and Mann-Whitney tests (α=.05)., Results: The mean vertical misfit values when all screws were tightened was 5.9 ±3.6 μm for CAD/CAM-fabricated zirconia, 1.2 ±2.2 μm for CAD/CAM-fabricated cobalt-chromium frameworks, 11.8 ±9.8 μm for conventionally fabricated cobalt-chromium frameworks with premachined abutments, and 12.9 ±11.0 μm for the conventionally fabricated frameworks with castable abutments; the Mann-Whitney test found significant differences (P<.05) among all frameworks, except between the conventionally fabricated frameworks (P=.619). No significant differences were found among the groups for passive fit gap measurements (P>.05)., Conclusions: When all of the screws were tightened, the CAD/CAM frameworks exhibited better fit accuracy compared with the conventionally fabricated frameworks. High levels of passive fit were achieved for the evaluated techniques., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose: To observe the photoelastic stress patterns generated around implants in relation to variations in the diameter and total number of implants supporting fixed complete-arch mandibular frameworks., Materials and Methods: Three different implant configurations were analyzed (n = 3): 5 standard implants with diameters of 3.75 mm (C), 3 standard implants with diameters of 3.75 mm (3S), and 3 wide implants with diameters of 5.0 mm (3W). The samples were subjected to a vertical compressive load (1.33 kgf) applied at the end of the distal cantilever of the framework. The shear stresses were calculated around the implants, and the data were analyzed using one-way analysis of variance., Results: The implants nearest to the loading showed higher stress values regardless of the group. The C group showed lower shear stress when compared with the other groups (P = 0.001). No significant difference was observed between the 3W and 3S groups (P = 0.785)., Conclusion: A reduction in the number of implants, regardless of the implant diameter, showed higher stress concentration around the implants. Five-implant configuration showed lower stress concentration and seems to be more biomechanically predictable.

Nine phenolic compounds, quercetin, epi-catechin, catechin, 4-hydroxybenzoic acid, kaempferol 3-O-β-glucopyranoside, quercetin 3-O-β-glucopyranoside, quercetin 3-O-6"-trans-coumaroyl-β-glucoside, kaempferol 3-O-β-rutinoside and quercetin 3-O-β-rutinoside, were isolated from the EtOAc leaf extract of Rhizophora mangle (Rhizophoraceae) combining counter-current chromatography (CCC) and gel-filtration. A solvent system of n-hexane-ethyl acetate-methanol-water (1.5:6:1.5:6) was employed at the preliminary stage of EtOAc extract fractionation as it was shown to contain compounds that differed highly in their hydrophobicity. The obtained fractions were further purified by either CCC or gel-filtration depending on their complexity. The isolated compounds were analyzed by NMR spectroscopy and the proposed structures were confirmed by HRES/ESI/TOF MS. Some of these compounds were isolated and/or identified for the first time in R. mangle.

This study aims to investigate a possible correlation between vertical misfits and the stresses transmitted to implants from one-piece casted frameworks fabricated with 3 different materials: commercially pure titanium, cobalt chromium alloy, and nickel chromium titanium alloy. Twelve frameworks simulating screw-retained prosthesis were fabricated from a master cast with 5 implants. Each framework was screwed (20 Ncm) over a metal cast and the vertical mesial and distal misfits were measured using an optical microscope. The stresses transmitted to the implants were measured in a third model by a quantitative photoelastic analysis. Stress and vertical misfit data were statistically analyzed by ANOVA and least significant difference tests and the correlation tests were performed using Pearson Correlation Test (α = 0.05). Mean and standard deviation values of vertical misfit and stress over implants are presented, respectively: commercially pure titanium (29.09 ± 13.24 μm and 11.38 ± 9.23 kPa), cobalt chromium alloy (27.05 ± 10.30 μm and 15.83 ± 9.30 kPa), nickel chromium titanium alloy (24.95 ± 11.14 μm and 16.39 ± 9.51 kPa). There were no significant differences for vertical misfit (P = 0.285). Regarding the stress analysis, there were significant differences between commercially pure titanium, cobalt chromium alloy, and nickel chromium titanium alloy (P = 0.035), with the lowest values for the commercially pure titanium. It may be concluded that stress over implants was affected by different procedures and materials for framework production.

The current study evaluated prosthetic dental crowns obtained by optical scanning and a computer-aided designing/computer-aided manufacturing system using micro-computed tomography to compare the marginal fit. The virtual models were obtained with four different scanning surfaces: typodont (T), regular impressions (RI), master casts (MC), and powdered master casts (PMC). Five virtual models were obtained for each group. For each model, a crown was designed on the software and milled from feldspathic ceramic blocks. Micro-CT images were obtained for marginal gap measurements and the data were statistically analyzed by one-way analysis of variance followed by Tukey's test. The mean vertical misfit was T = 62.6 ± 65.2 μm ; MC = 60.4 ± 38.4 μm; PMC = 58.1 ± 38.0 μm, and RI = 89.8 ± 62.8 μm. Considering a percentage of vertical marginal gap of up to 75 μm, the results were T = 71.5%, RI = 49.2%, MC = 69.6%, and PMC = 71.2%. The percentages of horizontal overextension were T = 8.5%, RI = 0%, MC = 0.8%, and PMC = 3.8%. Based on the results, virtual model acquisition by scanning the typodont (simulated mouth) or MC, with or without powder, showed acceptable values for the marginal gap. The higher result of marginal gap of the RI group suggests that it is preferable to scan this directly from the mouth or from MC.

This paper describes the isolation of flavonoids and other aromatic compounds from an ethyl acetate extract of leaves of Siparuna glycycarpa using stepwise elution counter-current chromatography (CCC). The elution profile yielded the following compounds: diglycosylated flavonoids, quercetin 3-O-rutinoside and quercetin 7-O-rutinoside, followed by monoglycosylated flavonoids, kaempferol-3-O-β-glucopyranoside, kaempferol-3-O-β-rhamnopiranoside, kaempferol-3-O-β-6''(p-coumaroyl) glucopyranoside, and quercetin-3-O-β-glucopyranoside, and then free phenolics, protocatechuic acid, and 2',6'-dihydroxy-4, 4'-dimethoxydihydrochalcone, which shows that this type of elution covers a broader range of polarity than the traditional isocratic mode. This makes it more suitable to perform separations of mixtures containing large differences in hydrophobicity. A GC analysis of a blank CCC run was performed to determine if changes in the mobile phase composition affect the chromatographic process. Results showed a gradual variation of the composition of the mobile phase emerging after the step gradient, favoring the selectivity of the solvent system., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Purpose: There is a variety of implant/abutment (I/A) junctions for the connection of implant-supported prostheses. The aim of this work was to compare the shear stress distribution in three types of I/A interfaces after application of oblique loading on the abutments, simulating loading on an anterior tooth., Materials and Methods: Similar wide unthreaded and cylindric implants (13.0 mm in length and 5.0 mm in diameter) and abutments were fabricated and embedded in photoelastic acrylic resin. The I/A assemblies featured three different I/A interfaces: external hex, internal hex, and internal taper. The samples were submitted to a compressive load of 0.6 kgf, which was applied to the abutment at an angle of 135 degrees. The maximum shear stresses were determined and observed at 21 points around the implants in the photoelastic models (n = 4). Graphics describing the maximum shear stress (y-axis) and the analyzed points (x-axis) were created, and the curve areas were calculated. The Kruskal-Wallis test was applied to analyze the results (P < .05)., Results: There were no statistically significant differences between the groups (P = .058)., Conclusion: All of the wide-diameter I/A junctions presented similar behavior under oblique loading and appeared to be suitable to support prostheses that could receive this type of loading.

The purpose of this study was to warn the dental community about a possible problem in function with partial implant-supported prostheses used for long periods. The misalignment between natural teeth and the implant-supported prosthesis on teeth 11 and 12, observed in a 14-year clinical follow-up, illustrates the fact. The metal-ceramic crowns were placed in 1995 after a rigorous occlusal adjustment. Evaluations were made at 4, 6, 9, and 14 years, when it was noticed that the restorations were positioned palatally and extruded in comparison with the natural teeth. After 9 years, a greater discrepancy was noticed, with anterior occlusion and esthetic changes. The possible causes have been discussed: occlusal problems, parafunctional habits, and natural movement. The first 2 options were discarded after clinical analysis and diagnosis. Therefore, the natural movement probably deriving from an interaction of mechanical and genetic factors might have been the cause. The implants do not have periodontal ligaments but rather ankylosis, so they do not suffer those movements. This case emphasizes the need to inform patients that implants can last more than 10 years in function, but this is not the case with restorations, which lose function and esthetics and must be replaced.

Purpose: The aim of this retrospective study was to evaluate the long-term survival rates and the frequency of complications associated with single implants and their associated restorations., Materials and Methods: A retrospective cohort study was performed in patients who received dental implants between 1997 and 2007. The cohort included patients who had a single implant restored with a cemented or screwed restoration that had been in function for more than 2 years. The cumulative implant survival rates and peri-implant conditions (marginal bone loss, pocket depth, and plaque, gingival, and bleeding indices), as well as prosthodontic maintenance requirements, were evaluated. Descriptive statistics, the chi-square test, and regression models were used., Results: Seventy-three implants were placed in 44 patients (32 women, 12 men; mean age, 48 years). All implants were available for follow-up after 2 to 13 years (mean follow-up, 60 months). The overall cumulative 5-year survival rates for implants were 95.9%, and most of the prostheses (98.6%) remained functional throughout the observation period. The overall frequency of complications was 29.6% (4.3% inflammatory, 22.5% prosthetic, 2.8% operative). The average peri-implant marginal bone loss was 1.8 mm. Peri-implant soft tissue conditions such as plaque and bleeding indices and pocket depths were also satisfactory. However, the presence of inflammation was significantly associated with pocket depth and gingival keratinized mucosa. The need to retighten loose abutment screws (21%) was the most frequent prosthodontic maintenance performed. However, all loose abutment screws occurred in prostheses retained with titanium screws, and 92.9% of the prostheses had a UCLA-type abutment., Conclusion: The implants and the associated prosthetic constructions used in this study showed excellent survival rates. However, there was a high frequency of prosthetic complications associated with titanium screws and UCLA cast abutments. Other prosthetic components may have yielded different results.

Purpose: This study sought to evaluate the influence of methodologic aspects on variations in the findings of in vitro microleakage studies of the implant-abutment interface., Materials and Methods: The MEDLINE, EMBASE, and Cochrane Library databases were consulted for in vitro studies published between 1990 and August 2011. Date from the studies that met the inclusion and exclusion criteria were arranged in tables and subjected to descriptive analysis., Results: Twenty-one studies were found to be eligible for the analysis after application of the inclusion/exclusion criteria. Sixteen studies used bacteria (76.2%), one used a bacterial toxin (4.76%), one used saliva (4.76%), two employed dyes (9.52%), and one used a combination of dyes and bacteria (4.76%). Eight studies evaluated microleakage from the inner portion of the implant to the external portion (38.1%) and nine examined the reverse (42.85%), while four studies investigated the relationship between them (19.05%). The volume inoculated inside the implants ranged from 0.1 to 5.0 mL. The bacterial concentrations used in the tests ranged from 2.41 x 10⁶ to 8 x 10⁸ colony-forming units/mL. Oral bacterial flora; mixtures of bacteria, toluidine blue, and gentian violet; and lipopolysaccharide of Salmonella enterica bacterial toxins were used. The monitoring period of test results ranged from 24 hours to 11 weeks for bacteria, 5 minutes to 7 days for dye, and 7 days for bacterial toxins. In four studies, microleakage was correlated with the size of the implant-abutment microgap. The external-hexagon implant configuration showed the greatest microleakage, followed by internal-trilobe, internal-hexagon, and internal-taper configurations., Conclusion: The lack of standardization hinderd comparisons of the studies and could explain the divergent results. It is suggested for future studies that special emphasis be placed upon inoculation and analysis of the specific volume for each system, lower concentrations of inoculated bacterial suspensions, and shorter follow-up time when using bacteria.

Three flavonoids--2',4',6'-trihydroxy-4'-O-β-D-glucopiranosyl dihydrochalcone, 1, pinocembrin-7-O-(-neohesperidoside, 2 and pinocembrin-7-O-(-(6″-O-acetyl) neohesperidoside, 3--were successfully isolated from the EtOAc extract of leaves of Sparattosperma leucanthum (Vell.) K. Schum (Bignoniaceae) using a two-step counter-current chromatography (CCC). Two different CCC machines were used, with different column axes (P.C. Inc., vertical orientation axis and AECS Quattro HTPrep, horizontal orientation axis). Detailed studies of flavonoids behaviour in several solvent systems made possible the use of the best system for their isolation. HEMWat and its modifications--exchange of alcohol and addition of a fifth solvent--were tested for isolation of the three compounds in a single run, but good K and α values were not achieved. So, HEMWat 4:10:4:10, with upper phase as mobile, was used to isolate compound 3. A mixture of compounds 1 and 2 was recovered and submitted to a new CCC fractionation using a more polar solvent system: EBuWat 8:2:10, upper phase as mobile. Butironitrile-acetonitrile-water (BuCN-ACN-H₂O) 5:10:10, upper phase as mobile, was also used for the isolation of the mixture containing compounds 1 and 2, in order to increase the solubility of the compounds in the CCC solvent system. It is the first time that the system BuCN-ACN-H₂O is described in literature., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Lower conventional complete dentures were converted to overdentures retained by two implants with an immediately loaded bar-clip system (n 16). The masticatory performance test was carried out using 'Optocal' after forty chewing strokes. Nutritional condition was evaluated by means of a Mini-Nutritional-Assessment questionnaire. No individual was classified as malnourished. The masticatory performance test demonstrated a statistically significant difference before conversion (baseline) and 3 and 6 months after conversion of the lower conventional complete denture to an implant-retained overdenture (paired-samples t test; P < 0·05). A statistically significant difference before and after 6 months of conversion for nutritional condition (Wilcoxon test; P < 0·05) was also observed. The association between masticatory performance and nutritional assessment demonstrated that a statistically significant difference between masticatory performance of the subgroups classified at baseline as nourished (22·43 %) and those at risk of malnutrition (3·9 %) was only evidenced before conversion (P = 0·006). After the conversion from a lower conventional complete denture to an implant-retained overdenture, at 3 months, the risk of malnutrition and nourished at baseline did not present significant differences in masticatory performance. Nonetheless, the mean masticatory performance potential was 19·86 and 31·98 % for subgroups classified at baseline as at risk of malnutrition and nourished, respectively (P = 0·187). The results before conversion were less favourable for masticatory performance and nutritional condition. The increased retention of the mandibular prosthesis allowed improvement in masticatory performance and nutritional condition.

Flavonoids form a large class of important naturally occurring bioactive compounds. Their isolation and purification from natural sources can sometimes be very difficult and time-consuming when traditional phytochemical techniques are used. Countercurrent chromatography (CCC), a support-free liquid-liquid partition chromatography technique, is very useful for the isolation of polar compounds and its use is increasing in the natural products field. In this paper, we propose strategies of solvent system selection for the isolation of flavonoids by CCC, based on data from the literature, plus incorporation of own practical experiences. The selected references report the isolation of over 300 different flavonoid compounds from more than 100 plant species, using 40 different solvent systems, showing the versatility of this technique. The solvent system hexane-ethylacetate-methanol-water is proposed as a starting point for the separation of samples containing free flavonoids, as it was cited in more than 60% of the papers. A "fine tuning" step is proposed at each level of this solvent family. Other modifications include exchanging the alcohol in the system as well as introducing a fifth solvent. The solvent system ethyl-acetate-butanol-water is proposed as the starting point for glycosylated flavonoids. Other solvent systems are also discussed. The use of gradients is proposed for samples containing both free and glycosylated flavonoids, as the polarity window is larger in these cases. High-speed countercurrent chromatography was used in 89% of the reviewed data.

This study compared vertical and passive fit of one-piece cast frameworks made with 3 different materials: commercially pure titanium (CP Ti - G1), cobalt-chromium alloy (Co-Cr - G2) and nickel-chromium-titanium alloy (Ni-Cr-Ti - G3). Fifteen frameworks were obtained simulating bars for fixed prosthesis in a model with 5 implants. The passive and vertical fit of the framework interface was measured using an optical microscope at x30 magnification. Data were statistically analyzed by ANOVA and LSD tests (α=0.05). Mean and standard deviation values for passive fit and vertical fit were, respectively: G1 [472.49 (109.88) µm and 29.9 (13.24) µm], G2 [584.84 (120.20) µm and 27.05 (10.30) µm], and G3 [462.70 (179.18) µm and 24.95 (11.14) µm]. For vertical fit, there were no significant differences among G1, G2 and G3 (p=0.285). There were no significant differences for passive fit between G1 and G3 (p=0.844), but both differed significantly from G2 (p=0.028 and p=0.035, respectively), which showed the highest misfit values. It may be concluded that the vertical fit of frameworks was not affected by the tested materials, and that one-piece cast frameworks resulted in inadequate passive fit. The Co-Cr alloy presented the worst values for passive fit.

This study investigated whether there is a direct correlation between the level of vertical misfit at the abutment/implant interface and torque losses (detorque) in abutment screws. A work model was obtained from a metal matrix with five 3.75 x 9 mm external hex implants with standard platform (4.1 mm). Four frameworks were waxed using UCLA type abutments and one-piece cast in commercially pure titanium. The misfit was analyzed with a comparator microscope after 20 Ncm torque. The highest value of misfit observed per abutment was used. The torque required to loose the screw was evaluated using a digital torque meter. The torque loss values, measured by the torque meter, were assumed as percentage of initial torque (100%) given to abutment screws. Pearson's correlation (alpha=0.05) between the misfit values (29.08 +/- 8.78 microm) and the percentage of detorque (50.71 +/- 11.37%) showed no statistically significant correlation (p=0.295). Within the limitations of this study, it may be concluded that great vertical misfits dot not necessarily implies in higher detorque values.

Implantology has allowed more options for rehabilitation of complete and partially edentulous patients. The professional should describe all possible alternatives to the patient, addressing all the positive and negative aspects of each possibility, such as treatment time, complexity of surgical procedures, and the final cost. The patient should select the best cost-benefit relationship because fixed prostheses are often not the option of choice for the patient. The aim of this article is to present one possible treatment option for the completely edentulous patient by use of implants to support and retain a removable complete or partial prosthesis. The clinical situations were rehabilitated by the use of a milled bar screwed to the implants to support a removable prosthesis with attachments and a milled metallic groove, which provide many advantages to the patient.

The continuous technological advance and increasing availability of new base metal alloys and ceramic systems in the market, coupled to the demands of daily clinical practice, have made the constant evaluation of the bond strength of metal/porcelain combinations necessary. This study evaluated the metal/porcelain shear bond strength of three ceramic systems (Duceram, Williams and Noritake) in combination with three nickel-chromium (Ni-Cr) alloys (Durabond, Verabond and Viron). Thirty cast cylinder specimens (15 mm high; 6 mm in diameter) were obtained for each alloy, in a way that 10 specimens of each alloy were tested with each porcelain. Bond strength was measured with an Emic screw-driven mechanical testing machine by applying parallel shear forces to the specimens until fracture. Shear strength was calculated using the ratio of the force applied to a demarcated area of the opaque layer. Mann-Whitney U test was used for statistical analysis of the alloy/ceramic combinations (p<0.05). Viron/Noritake had the highest shear bond sregnth means (32.93 MPa), while Verabond/Duceram (16.31 MPa) presented the lowest means. Viron/Noritake differed statistically from other combinations (p<0.05). Viron/Duceram had statistically significant higher bond strengths than Verabond/Duceram, Verabond/Williams and Durabond/Noritake (p<0.05). It was also found significant difference (p<0.05) between Verabond/Noritake, Verabond/Duceram and Durabond/Noritake. No statistically significant difference (p>0.05) were observed among the other combinations. In conclusion, the Noritake ceramic system used together with Viron alloy presented the highest resistance to shear forces, while Duceram bonded to Verabond presented the lowest bond strength. Viron/Duceram and Verabond/Noritake provided intermediate results. The combinations between the Williams ceramic system and Ni-Cr alloys had similar shear strengths among each other.