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Purpose: This study investigated whether additive manufactured (AM) surfaces inhibit accumulation of bacterial biofilm on the surfaces of Ti-6Al-4V alloy dental implants. Bacterial biofilms are thought to cause peri-implant disease, which develops in mucosa surrounding titanium (Ti) and Ti alloy dental implants and can lead to bone loss and implant failure., Methods: Accumulation of a Streptococcus mutans (ATCC 25175) biofilm on Ti-6Al-4V alloy was compared in relation to fabrication method, ie, AM using electron beam melting (EBM) or laser beam melting (LBM). Conventional lost-wax casting was used as positive control, and Teflon was used as negative control. Biofilm accumulation on the alloys and negative control (each n = 10) was conducted at 37°C under anaerobic conditions. After 4 h, the number of metabolically active S. mutans bacteria adhering to the alloy was determined with a bioluminescence assay., Results: The quantitative roughness values of the specimens, before exposure to bacteria, ranked EBM > LBM > cast > Teflon., Conclusion: The amount of biofilm accumulation on the investigated AM metals and cast metal controls did not significantly differ.

Statement of Problem: Although pure titanium is known to have good biocompatibility, a titanium alloy with better strength is needed for fabricating clinically acceptable, partial removable dental prosthesis (RDP) frameworks., Purpose: The mechanical properties of an experimental Ti-5Al-5Cu alloy cast with a 2-step investment technique were examined for RDP framework applications., Material and Methods: Patterns for tests for various properties and denture frameworks for a preliminary trial casting were invested with a 2-step coating method using 2 types of mold materials: a less reactive spinel compound (Al(2)O(3)·MgO) and a less expensive SiO(2)-based material. The yield and tensile strength (n=5), modulus of elasticity (n=5), elongation (n=5), and hardness (n=8) of the cast Ti-5Al-5Cu alloy were determined. The external appearance and internal porosities of the preliminary trial castings of denture frameworks (n=2) were examined with a conventional dental radiographic unit. Cast Ti-6Al-4V alloy and commercially pure titanium (CP Ti) were used as controls. The data for the mechanical properties were statistically analyzed with 1-way ANOVA (α=.05)., Results: The yield strength of the cast Ti-5Al-5Cu alloy was 851 MPa and the hardness was 356 HV. These properties were comparable to those of the cast Ti-6Al-4V and were higher than those of CP Ti (P<.05). One of the acrylic resin-retention areas of the Ti-5Al-5Cu frameworks was found to have been incompletely cast., Conclusions: The cast biocompatible experimental Ti-5Al-5Cu alloy exhibited high strength when cast with a 2-step coating method. With a dedicated study to determine the effect of sprue design on the quality of castings, biocompatible Ti-5Al-5Cu RDP frameworks for a clinical trial can be produced., (Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: The increased use of adhesive resin cements in bonded prosthetic restorations has led to restorations debonding under function., Purpose: This investigation evaluated the differences in the flexural strength of new adhesive resin cements as a function of specimen age and storage condition., Materials and Methods: Four new dual-cure cements were compared to C/B Metabond. Twenty specimens of each of the five cements were prepared in a rectangular glass mold (25 x 2 x 2 mm). The new cements were light-activated with a 550 mW/cm(2) lamp for 80 seconds on both the top and bottom surfaces. The auto-cured cement was allowed to set according to manufacturer's directions. Half the specimens were tested immediately after curing while the other half were stored in distilled water at 37 degrees C for 30 days. A three-point bending test was performed using an Instron at a crosshead speed of 1 mm/min. The results were analyzed by analysis of variance and Scheffé tests ( p < 0.05) to examine the effect of specimen age and storage condition., Results: RelyX ARC exhibited a significantly higher flexural strength compared with Calibra and Panavia F when tested immediately. The standard cement, C/B Metabond, deformed and did not fracture at the immediate test time. After storage, the flexural strength had significantly improved from the immediate test time for Calibra, Cement-It, Panavia F, and C/B Metabond. However, there were no significant differences in the flexural strength among the cements when tested after 30 days in water at 37 degrees C., Conclusion: Immediately after curing, these new adhesive resin cements are not equivalent, as evidenced by the significant variability in the measured flexural strength. The distinctions among the cements diminish after aging in water, which may be due to residual polymerization or a plasticizing effect from water absorption., Clinical Significance: When light-cured, all the new adhesive resin cements have greater early strengths than the auto-cured cement; however, the wide variation in immediate bending strength suggests that some cements may be more appropriate for use in high-stress clinical situations such as resin-bonded fixed partial dentures.

Statement of Problems: Research-based assessments of the quality of removable partial dentures (RPDs), especially within a large patient population, are lacking., Purpose: This study evaluated the prevalence and quality of RPDs by use of the National Health and Nutrition Survey (NHANES III) data set., Material and Methods: Estimates of the health and nutritional status of the American population were obtained from the NHANES III data set (1988-1994). Calibrated dentists performed dental examinations on 17,884 adults. If the subject wore an RPD, its quality was assessed with 5 criteria: integrity, tooth wear, the presence of temporary reline material or adhesive, stability, and retention. In this study, the data on RPD defects were used to assess the prevalence of problems. The original population was divided into 4 subgroups: paired RPD data = subjects wearing both maxillary and mandibular RPDs (n = 600 prostheses, 300 maxillary and 300 mandibular); single RPD data = subjects with only one RPD (n = 1003 prostheses, 511 maxillary and 492 mandibular); maxillary versus mandibular RPD data = all subjects with all RPDs (n = 1603 prostheses, 811 maxillary and 792 mandibular); and pooled RPD data = all subjects with a single RPD plus subjects with 2 RPDs, counting only the RPD with the most defects (n = 1303 prostheses, 674 maxillary and 629 mandibular). The subjects were analyzed with descriptive statistics. The distribution of defects in the RPDs was examined for possible associations with chi(2) tests. The paired data for patients with both maxillary and mandibular RPDs were analyzed with Wilcoxon signed rank tests. The prevalence of RPDs as a function of patient age and the association between RPD defects and patient age were analyzed with chi(2) tests. The results were considered highly significant at P<.0001 and significant at P<.05., Results: Of the 17,884 adults who underwent a dental examination, 1306 had RPDs. Three patients were excluded because their records were incomplete, leaving 1303 patients available for analysis. Most of the prostheses examined (65%) had at least 1 defect. Lack of stability was the most prevalent single defect. Distinctions in the type and prevalence of defects were observed between mandibular and maxillary RPDs. Mandibular RPDs had significantly more problems related to retention, whereas maxillary RPDs had significantly more problems related to the presence of reline material and to integrity defects. Tooth wear defects were significantly associated with patient age (P<.0001). Only one third of the RPDs were considered satisfactory according to NHANES III criteria., Conclusion: A review of the database used in this study indicated that, in spite of a decline in tooth loss, RPDs are still used in all age cohorts, including young adults. A large number of RPDs were found to have defects.

Purpose: The hypothesis tested in this pilot study was that materials used for the palatal region of a maxillary denture affect the comfort of the maxillary denture in xerostomic patients., Materials and Methods: Xerostomic complete denture wearers were selected to test three different maxillary dentures that were made with different palatal materials. Each denture was worn for a period of 2 weeks. The Kapur Index was used to measure retention. The Oral Health Index Profile (OHIP) was used to determine the patient's perception of each denture after the 2-week period. At the end of the study, the patients were asked to select which of the three dentures they would like as their primary denture., Results: All participants chose the metal-palate dentures, and 4 of 5 selected the titanium-palate denture as their primary denture. Statistical analysis of the OHIP demonstrated that the metal-palate dentures were perceived as being more comfortable than the acrylic-resin dentures., Conclusion: This pilot study suggests that for xerostomic patients who have worn complete dentures, their selection of a metal-palate denture as their primary prosthesis strongly suggests that these dentures have properties that make them more comfortable to the patient than acrylic dentures. Subjective patient measurements supported this conclusion that the metal-palate dentures were preferable, while the evaluation method available to the clinician failed to discriminate among the prostheses.

Statement of Problem: The use of titanium alloys for removable partial dentures is an increasingly popular application. While the flexibility of titanium would allow for cast clasps to be placed in deeper undercuts than advisable with cobalt-chromium, it is possible that the retentive forces of the titanium clasp might not maintain sufficient retention after repeated flexing of the clasp arm during insertion and removal of the partial denture., Purpose: This study assessed the characteristics of cast clasps made of titanium and titanium alloys to determine whether these materials are suitable alternatives for removable partial denture applications., Material and Methods: Removable partial denture clasps at two undercut depths were fabricated from commercially pure titanium, titanium alloy (Ti-6A1-4V), and cobalt-chromium. Loss of retention force was measured as the clasps underwent 3 years of simulated clinical use. The data were subjected to ANOVA and Scheffé's tests to determine differences. Evidence of casting defects and porosity was evaluated by radiographic examination and nonparametric statistics. SEM microscopy was used to observe surface characteristics that were described qualitatively., Results: For the 0.75 mm undercut specimens, there was less loss of retention for clasps made from pure titanium and titanium alloy than for cobalt-chromium clasps. Porosity was more apparent in the pure titanium and titanium alloy clasps than in those made from cobalt-chromium, but the amount of porosity did not correspond to evidence of fractures or permanent deformation., Conclusions: The long-term retentive resiliency of the pure titanium and titanium alloy clasps suggests that these materials are suitable for removable partial dentures.

Statement of Problem: Controversy surrounds the use of hydrofluoric acid to prepare precementation surfaces of indirect composites., Purpose: This study was conducted to compare effects of combining hydrofluoric or orthophosphoric acid with microetching as precementation treatments., Material and Methods: Nine specimens of three composite materials were prepared to simulate heat-cured indirect restorations. The specimen surfaces were prepared with one of three treatments. Adhesive Bond II and Twinlook cements were used to bond a phosphoric acid-etched disk of P50 to the treated surface. Analysis of variance and Scheffé tests were used to assess the bond strength data. Scanning electron microscopy and microscopic analysis of the fractured and treated surfaces were also performed., Results: Bond strengths for all surface treatments did not significantly differ. Hybrids had a higher bond strength with etching than microfills, and mechanical roughening produced the greatest bond strengths with microfills. Microetching with orthophosphoric acid produced higher bond strengths than microetching with hydrofluoric acid on hybrids., Conclusions: Acid etching alone is not sufficient to produce effective bond strengths, and hydrofluoric acid treatments are detrimental to the resin composite.

Purpose: A major challenge of composite-coated metal restorations is creating a strong bond between the two materials. This study was conducted to compare the bond strengths between composite and metal alloys using two silicoating treatments; the Silicoater Classic and the Silicoater MD (Kulzer Inc, Irvine, CA)., Materials and Methods: The Classic uses a pyrolytically applied silica glass and the MD process is an oven sintering of a metal oxide silicate layer. Two types of specimens of three different alloys were cast (Deva4: 51Au38Pd, G-Cast: 50Au32Ag12Cu [Degussa Corp. South Plainfield, NJ]; Ticonium: 70Ni15Cr [CMP Industries, Inc, Albany NY]). The specimens were silicoated with either the Classic or the MD process and opaque resin and composite (Dentacolor, Kulzer Inc) were bonded to each surface. A total of five control and 10 thermocycled (5,040 cycles 0 degree C to 67 degrees C; dwell time, 1 minute) specimens were fabricated for each alloy and specimen type. Two bond strength tests were used; a three-point flexure test and a shear bond strength test. Data were analyzed using a multivariate analysis of variance (MANOVA) and a Tukey's multiple comparison test., Results: The standard deviations of the shear bond strength values ranged from +/- 2.30 to +/- 17.82.kg; thus, there was no significant difference in these results. Bond strength ratios were calculated from the flexure strength data. After thermocycling, the Silicoater MD produced significantly higher (P < 0.05) bond strength ratio values compared with the Silicoater Classic for Deva-4 (MD, 9.6 +/- 1.5 v Classic, 4.7 +/- 0.9) and G-Cast (MD, 11.6 +/- 1.2 v Classic, 3.9 +/- 0.5) but lower values for Ticonium (MD, 4.5 +/- 0.4 v Classic, 6.9 +/- 0.9)., Conclusion: The Silicoater MD produced higher bond strength ratio values with noble alloys, and the Silicoater Classic produced higher bond strength ratio results when base metal alloys were used, suggesting a possible correlation between the effectiveness of the coating processes and the compositions of the alloys. These findings suggest that, for optimum results, selection of the type of silicoating process should be based on the components of the alloy.

The mechanism by which xylazine raises plasma glucose but lowers insulin concentrations was examined in Holstein cows. Intravenous injection of xylazine (15-150 micrograms/kg) induced a dose-dependent hyperglycemia and hypoinsulinemia for 3-4 h. An alpha 2-adrenergic blocking agent, yohimbine, and an alpha 1- and alpha 2-adrenergic blocking agent, phentolamine, at 500 micrograms/kg each reduced or abolished xylazine-induced hyperglycemia and hypoinsulinemia. The alpha 1-adrenergic blocking agents, prazosin and phenoxybenzamine, at 500 micrograms/kg each did not exert such antagonism. Prazosin at the dose studied even prolonged xylazine-induced hypoinsulinemia. The alpha-adrenergic blocking agents alone at 500 micrograms/kg each did not change either plasma glucose or insulin concentrations. The present study suggests that xylazine-induced hyperglycemia and hypoinsulinemia are mediated by alpha 2-adrenergic receptors, possibly in beta-cells of pancreatic islets which inhibit the release of insulin. The present study further suggests the use of xylazine as a pharmacological tool in the study of adrenergic influence on in vivo insulin release.

It is believed that most patients with subarachnoid hemorrhage secondary to aneurysmal rupture experience some degree of cerebral vasospasm, although not all develop specific neurologic deficits. Management is complicated, and at present the outcome is often less than optimal. This article reviews the symptoms, predictors and pathophysiology of vasospasm, highlighting current theories of pathogenesis as well as their relationship to treatment. This information is essential for the neuroscience nurse to care adequately for these patients. A plan of care for the patient with cerebral vasospasm is included.

Alveolar lining material was obtained from gnotobiotic pigs; gnotobiotic pigs exposed to aerobes, anaerobes, or mixtures of both microorganisms; and conventional farm-raised pigs. Alveolar lining material concentrations of phosphatidylcholine, sphingomyelin, phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylglycerol, and lysolecithin were determined. Seventy-four pigs were allotted to the following groups: 1--gnotobiotes (n = 13), 2--gnotobiotes with aerobes (n = 6), 3--gnotobiotes with anaerobes (n = 31), 4--gnotobiotes with anaerobes and aerobes (n = 2), 5--gnotobiotes with facultative anaerobes (n = 9), and 6--conventionally farm-farrowed (n = 13). The conventionally raised pigs had lysolecithin, sphingomyelin, and phosphatidylinositol concentrations that were significantly different from those of all other groups of pigs. Phosphatidylethanolamine was significantly decreased in group 6 pigs when compared with that in all other groups. There were also statistically significant differences between the gnotobiotic (group 1) and the exposed gnotobiotic (groups 2, 3, 4, 5) pigs, although the differences were less pronounced. Since intestinal microbes produce alveolar lining material phospholipid differences, studies need to be concerned with phospholipid changes that occur after exposure to lung-specific microorganisms and with physiologic changes in lung function associated with the phospholipid changes.