Finishing and Polishing Procedures and Glaze Application on Physical Properties of a Fine-Structure Feldspathic Ceramic.

The aim of this study was to verify the effect of finishing and polishing procedures and glaze application on biaxial strength and surface properties of milled feldspathic ceramic blocks. Forty disc-shaped samples (14 mm diameter, 1.2 mm thickness) were divided in four groups (n = 10): C (control): no finishing and polishing; FP: finishing and polishing; G: glaze; and GFP: finishing and polishing + glaze. The specimens were subject to surface gloss (glossmeter) and roughness (profilometer) tests followed by biaxial flexural strength (universal testing machine) and Vickers hardness (microhardness tester) tests. The surface morphological analysis was performed by scanning electron microscopy (n = 3). Data were submitted to normality tests with Shapiro-Wilk, and one-way ANOVA followed by Tukey's post hoc test (α = 0.05). Group C showed the lowest gloss. For the hardness test, groups C, FP, and GFP obtained the highest values without significant differences between them. Regarding the biaxial strength test, group C showed the lowest mean value. Both finishing and polishing methods (FP and GFP) showed surface properties similar or better than the control, and with higher biaxial strength.

The Effect of Ethanol Associated with Universal Adhesive on Resin Composite Adhesion to Different Dentin Depths: A Long-Term In Vitro Study.

To evaluate the ethanol wet-bonding protocol with a universal adhesive in etch-andrinse and self-etch modes on microleakage and microtensile bond strength (µTBS) of resin composite to different dentin depth. Molars were distributed into groups according to protocol and dentin depth: universal adhesive (C - control), ethanol + universal adhesive (E), and phosphoric acid etch + ethanol + universal adhesive (PA+E). All protocols were applied to dentin at superficial, middle and deep depths. The specimens (n = 10) were submitted to microleakage and µTBS tests. Half of specimens were submitted to thermocycling (10,000 cycles; 5∘C/55∘C). Data were submitted to Spearman correlation (µTBS x microleakage) and three-way ANOVA (protocol, aging and depth), followed by Bonferroni post hoc test (α=0.05). PA+E group showed highest µTBS and lowest microleakage mean values in 24h. All groups presented similar µTBS mean values after thermocycling. The deep dentin showed less stable µTBS results. PA+E group presented highest microleakage mean values after thermocycling. Spearman's correlation showed a strong correlation between microleakage and µTBS. The PA+E group improved immediate adhesion and E group promoted a more stable µTBS in the long-term adhesion of universal adhesive. The aging for all protocols jeopardized the stability of the hybrid layer. The ethanol wet bonding technique associated with universal adhesive has enhanced the immediate result of the resin composite adhesion.

Longevity of Resin Composite and Amalgam Posterior Restorations: A Systematic Review.

OBJECTIVES: The objective of this systematic review was to compare the longevity of direct amalgam and composite resin restorations, in posterior teeth, through clinical, prospective or retrospective studies, with at least 5 years of follow-up. MATERIALS AND METHODS: Studies published in the last 15 years (from 2006 to 2021) were collected using the PubMed and Medline databases. RESULTS: The search strategy associated with the established inclusion and exclusion criteria resulted in a total of 17 articles. Factors related to failures in the performance of restorations were analyzed together with the clinical performance results of each material over the years of study, according to the methodology of each article. CONCLUSIONS: Regardless of the restorative material, the successful results over more than 5 years are due much more to the correct application of the technique, the operator's skill/knowledge and factors related to the patient, such as the type of tooth, number of faces involved in the restoration and oral hygiene.

Influence of Flat Occlusal Splint on Stresses Induced on Implants for Different Fixed Prosthetic Systems.

OBJECTIVE: The flat occlusal plate has been recommended to reduce stress concentration in implant prosthesis treatments. The purpose was to investigate the influence of the occlusal splint on three-element implant-supported fixed prosthesis. MATERIALS AND METHODS: A three-dimensional virtual model was created consisting of a cortical and spongy bone block simulating the region from first premolar to the maxillary first molar using two HE or MT implants (4 x 11mm) with Ti and/or Y-TZP abutments. The second premolar was the pontic of the prosthesis. The three-element fixed prosthesis with a zirconia infrastructure and Y-TZP coating were cemented, in addition to using a flat occlusal splint made of acrylic resin in the region. Combined axial and oblique loads of 100N and 300N were applied. RESULTS: The tensile stresses on MT implant bone tissue produced values of 4-19% lower than those of HE implants. The lowest differences were observed for oblique loading with an occlusal splint, with a 4% (Ti-Y-TZP) and 9% (Ti-Ti) decrease. When the compressive stresses were evaluated, HE implants produced lower values than MT implants. CONCLUSION: A significant increase was observed in the oblique loading stresses in the absence of occlusal splints, regardless of the applied load.

Influence of Different Ceramic Systems on Marginal Misfit.

OBJECTIVE: the aim of this study was to evaluate the marginal misfit at the interface between a ceramic coping and its abutment. METHODS: Twenty-four specimens were made with solid abutments. The specimens were divided into 3 groups according to the ceramic system (n = 8): Lava (zirconia), IPS e.max Press (lithium disilicate), and IPS Empress Esthetic (leucite). All copings were cemented with resin luting agent (RelyX U200) and the marginal misfit were evaluated at 3 different times: initial, after cementation, and after mechanical cycling using a linear measuring microscope (Measuring Microscope STM-Olympus) at a magnification of 40x. All specimens were subjected to mechanical cycling (1 million cycles) by an universal testing machine (Instron 8800). The results were statistically analyzed using Analysis of Variance and Student's t-test (α = 0.05). RESULTS: all groups showed an increase in the marginal misfit after cementation. The lithium disilicate group demonstrated the lowest interacial gap values at each evaluation (p = 0.001). The zirconia and leucite groups showed similar interfacial gap values (initial, p = 0.244; and post cementation, p = 0.751). CONCLUSIONS: the cementation increase the marginal misfit, but the mechanical cycling did not influence the marginal misfit of the ceramics systems evaluated.

Prolonged curing time reduces the effects of simulated pulpal pressure on the bond strength of one-step self-etch adhesives.

The aim of this study was to evaluate the effects of extended light-curing procedures on the microtensile bond strength (µTBS) of one-step self-etch adhesives (1-SEAs) submitted to simulated pulpal pressure. Coronal deep-dentin specimens were bonded using Clearfil S3 Bond (S3), Adper Easy Bond (EB), or G-Bond Plus (GB) following the manufacturers' recommendations and light-cured for 10 seconds or 40 seconds. The dentin-bonded specimens were stored in distilled water for 24 hours without pulpal pressure (control) or submitted to 20 cm H2O simulated pulpal pressure for 24 hours. The specimens were cut into matchsticks and subjected to µTBS testing. The data were statistically analyzed using the three-way analysis of variance and Tukey's tests (p<0.05). Debonded sticks were investigated through scanning electron microscopy. EB obtained higher bond strengths than GB and S3. However, prolonged light activation (40 seconds) provided higher µTBS for all adhesives when submitted to pulpal pressure. Conversely, pulpal pressure caused a drop in µTBS in EB and S3 when light-cured for 10 seconds. A mixed failure mode was mainly attained for the control groups, whereas the specimens submitted to pulpal pressure failed in the adhesive mode. The µTBS of GB was not affected by pulpal pressure when light-cured for 10 seconds. Adhesive was the most prevalent failure mode, except when light-cured for 40 seconds, which showed predominantly cohesive failure. Extended curing times improved the resistance of 1-SEAs to simulated pulpal pressure.

An exploratory study of the safety, tolerability and bioactivity of a single intravitreal injection of vascular endothelial growth factor Trap-Eye in patients with diabetic macular oedema.

AIM: The aim of the study was to assess the safety and bioactivity of a single intravitreal injection of vascular endothelial growth factor (VEGF) Trap-Eye in subjects with diabetic macular oedema (DMO). METHODS: Five subjects with DMO, foveal thickness > or =250 microm measured by optical coherence tomography (OCT), and best-corrected visual acuity (BCVA) between 20/40 and 20/320, were enrolled. Each participant received a single intravitreal injection of 4.0 mg of VEGF Trap-Eye followed by a 6-week observation period. Outcome measures included safety and biological activity, including changes in BCVA and excess retinal thickness assessed by OCT. RESULTS: Injections of VEGF Trap-Eye were well tolerated with no ocular toxicity. One patient had an unrelated serious adverse event: hospitalisation for cellulitis of the left foot 27 days after injection of VEGF Trap-Eye. Median baseline BCVA was 36 ETDRS letters read at 4 m (not ETDRS visual acuity score; Snellen equivalent: 20/50) and median baseline excess central 1 mm foveal thickness (FTH) was 108 microm. At 4 weeks after injection, the median excess FTH was 59 microm and the median improvement in BCVA was nine letters. At 6 weeks after injection, four of the five patients showed improvement in excess FTH (median 74 microm; 31% reduction from baseline, p = 0.0625) and four of the five showed improvement in BCVA (median improvement of three letters). CONCLUSIONS: A single intravitreal injection of 4.0 mg of VEGF Trap-Eye was well tolerated and preliminary evidence of bioactivity was detected. These findings support additional studies investigating multiple injections of VEGF Trap-Eye in patients with DMO.

Progressing prostate carcinoma.

In the Karnell Cancer Center Grand Rounds, we present a patient who underwent radical prostatectomy with bilateral pelvic lymphadenectomy, but had positive margins and subsequently developed local recurrence and then systemic disease. Pathologic and radiologic aspects of his disease are discussed. Therapeutic options at different stages of the disease are examined from the point of view of the urologist, radiation oncologist, and medical oncologist. The surgical portion of the discussion focuses on the selection of initial therapy. Both the selection of surgical candidates and choice of pre- or post-operative therapy in patients can be aided by prognostic tools looking at several variables, including prostate-specific antigen (PSA) level, Gleason score of the tumor, seminal vesicle invasion, extracapsular invasion, and lymph node involvement. Low-risk patients can be treated with monotherapy, such as radical prostatectomy, external beam radiation therapy, prostate brachytherapy, or cryosurgical ablation of the prostate. Higher risk patients may require adjuvant and possibly neoadjuvant therapy in addition. The radiation portion of the discussion focuses on the use of radiation therapy as salvage for relapsing disease. Of particular importance is the point that treating high-risk patients whose PSA levels have started to rise but are less than 1 ng/ml results in a long-term PSA control rate as high as 75%, but that limiting the use of salvage radiation therapy to patients with high PSA levels or biopsy confirmation of local recurrence in the face of a negative bone scan results in biochemical long-term control of less than 40%. In the medical oncology part of the discussion, the major focus is on the use of chemotherapy to treat patients whose disease has become resistant to hormonal therapy. Mitoxantrone plus a corticosteroid has been found to offer significant palliation for such patients. Combination therapy with estramustine plus taxanes, other microtubule inhibitors, or other agents such as topoisomerase II inhibitors, has been found to cause shrinkage of measurable soft tissue disease and diminution of serum PSA levels. The development of effective hormonal and chemotherapeutic drugs for treatment of metastatic disease has led to new interest in adjuvant and neoadjuvant therapy of high-risk patients.

Evolution of temporal lobe hypoperfusion in transient global amnesia: a serial single photon emission computed tomography study.

Previous functional neuroimaging studies performed during transient global amnesia (TGA) have not answered the central question regarding the etiology of TGA, namely: whether the observed hypoperfusion in the mesial temporal lobe structures reflects a primarily ischemic process or whether it represents a secondary phenomenon resulting from locally decreased metabolism. The authors performed Tc 99-m-bicisate brain single photon-emission computed tomography (SPECT) scanning in a 66-year-old man during an episode of TGA, 24 hours after the episode and 3 months after the episode. To the authors' knowledge, this is the only reported study in which a follow-up SPECT scan was performed within 24 hours. The initial study showed bilateral mesial temporal lobe hypoperfusion that partially resolved after 24 hours and returned to normal at 3 months. Resolution of the SPECT scan abnormalities correlated well with resolution of the memory loss. These findings agree with previously reported SPECT, positron-emission tomography (PET), and diffusion magnetic resonance imaging (MRI) studies that indicate the mesial temporal lobe structures as the major site of pathology in TGA. The authors suggest that a process causing decreased local metabolism, such as cortical spreading depression, constitutes the primary pathophysiologic mechanism in this case.

The role of 99m-Tc HMPAO SPECT in the diagnosis of Creutzfeldt-Jacob disease.

A patient with acute dementia underwent imaging of the brain with technetium-99m hexamethylpropyleneamine oxime single-photon emission computed tomography. Regional perfusion abnormalities were identified in multiple locations, particularly in the left frontal lobe. This information was used to direct an open brain biopsy, which led to a diagnosis of Creutzfeldt-Jacob disease.

Interaction between phenylalanine and antisense nucleosides and the effect of pH and salts on the strength of interaction.

The interaction of 12 antisense nucleosides with phenylalanine (Phe), and the effect of pH and salts on the strength of interaction was studied by charge-transfer reversed-phase thin-layer chromatography. Phe significantly decreased the lipophilicity of nucleosides. This effect may be due to the interaction between the more hydrophilic Phe and the more lipophilic nucleosides, resulting in charge-transfer complexes of moderate lipophilicity. The relative strength of interaction was the weakest in acidic and the strongest in alkaline environment. This finding indicates the partially or entirely hydrophilic character of the interaction. Salts influenced to a lesser extent the interaction, their effect depended both on the concentration and on the type of cation. The relatively low impact of salts on the strength of interaction suggests that other than hydrophilic forces are involved in the Phe - antisense nucleoside interaction.

Gastrointestinal bleeding: improved localization with cine scintigraphy.

Studies of gastrointestinal bleeding, done with technetium-99m-labeled red blood cells were performed in 52 consecutive patients to determine whether cinematic acquisition and display localized sites of bleeding more accurately than did conventional static imaging. Computerized images were obtained for 15 seconds per image in 15-minute sets. Interpretations based on a cinematic display were compared with those based on standard 1-minute images obtained every 5 minutes. Pathologic confirmation of a site of bleeding was obtained in 21 patients. The cinematic display demonstrated bleeding not seen on static images and yielded either more accurate localization or increased sensitivity in eight of 21 patients (38%). Linear regression showed that the cinematic correlation (r = .98) to the actual site of bleeding was better than either of two readers' interpretations of the static display (r = .93, P less than .02; and r = .88, P less than .0004). The mean error for cinematic localization of bleeding (0.4 anatomic segments +/- 0.6 [standard deviation]) was less than that for the static interpretations (1.1 anatomic segments +/- 1.4) (P less than .01). It is concluded that computerized cinematic acquisition and display of scintigrams improves localization and detection of gastrointestinal bleeding.

Comparison of left anterior oblique and geometric mean gastric emptying.

A left anterior oblique image (LAO) and the geometric mean of anterior and posterior counts have both been proposed as methods for acquiring gastric emptying data. Both approaches are used to correct for the changes in attenuation that occur as the depth of radiolabeled solids changes during gastric emptying. These two methods were compared by using a power exponential curve fit to calculate a lag phase, an equilibrium emptying rate, and a half-time for gastric emptying in 20 patients. There were no significant differences (mean +/- 1 s.e.m.) in the measured half-emptying time (115 +/- 10 versus 104 +/- 7 min) (p = 0.08) or rate of gastric emptying (0.015 +/- 0.002 versus 0.015 +/- 0.002 min-1) (p = 0.56) for LAO imaging versus the geometric mean. However, the LAO measurements of the lag phase were significantly higher (69 +/- 7 min) than the geometric mean (53 +/- 6 min) measurements (p = 0.004). This resulted in 4/20 (20%) of patients with normal geometric mean lag phase measurements who would have been reclassified as abnormal using the LAO method.

Thallium-201 SPECT increases detectability of thyroid cancer metastases.

Thallium-201- (201Tl) chloride is known to accumulate in metastatic foci of differentiated thyroid carcinoma, but small and deep-seated lesions are generally not detectable by planar imaging. We have evaluated the use of 201Tl-chloride single-photon emission computed tomography (SPECT) in 41 post-thyroidectomy patients with differentiated thyroid carcinoma and one with medullary carcinoma; planar imaging alone was done in eight additional patients (total 50). Of 20 patients with known metastatic disease, planar 201Tl images were positive in 12 (60%) but SPECT revealed an additional 5 (25%) who had metastases (total 85%). SPECT revealed foci as small as 1.0 cm in the neck and 1.5 cm in the lungs, and was particularly useful in detection of disseminated micronodular pulmonary metastases, especially in patients whose scans were negative with diagnostic doses of 131I. Some pitfalls in interpretation of the tomographic reconstructions were found. Thallium-201 SPECT is a marked improvement over planar imaging in the detection of metastases of differentiated thyroid cancer.

Quantitative distribution of radiolabeled 5-aminosalicylic acid enemas in patients with left-sided ulcerative colitis.

Rectally administered suspensions of 5-aminosalicylic acid (5-ASA) are topically effective in treating left-sided ulcerative colitis. The extent to which the contents of these enemas are distributed to inflamed mucosal linings has not previously been determined. This study was undertaken to validate a technique for labeling 5-ASA with 99mTc and to quantitate the distribution of [99mTc]5-ASA in eight patients with left-sided ulcerative colitis. Eight patients underwent three colonic scintigraphic exams within five days, receiving a 60-ml radiolabeled 5-ASA enema into the unprepared rectum for each study, with sequential anterior abdominal images obtained for 4 hr. Activity within the rectum, sigmoid, descending, transverse, and ascending colon was quantitated. Over 50% of the labeled enema had advanced beyond the rectum in five of eight patients and in six of eight patients by 30 min and 60 min, respectively. The distribution of [99mTc]5-ASA was quantitatively reproducible when repeated in the same patient on different days, despite apparent visual differences. By 2 hr, the amount of the enema present within the rectum decreased significantly (P less than 0.05) compared to the initial distribution. The amount of enema present within the descending colon was increased significantly at 0.5 hr (P less than 0.05) and at 2 hr (P less than 0.01). There were no significant changes in the distribution from initial values for the sigmoid, transverse, or ascending colon at any time. In each of these cases the spread of the enema to or beyond the extent of disease was documented. In patients with left-sided ulcerative colitis, small volume [99mTc]5-ASA enemas reliably reach the area of inflammation.

Single photon emission computed tomography and renal pseudotumor.

Single photon emission computed tomography (SPECT), recently introduced into clinical nuclear medicine, potentially offers improved spatial resolution compared to planar imaging by eliminating activity from surrounding structures, and permitting three-dimensional reconstructions. Its clinical applications to date have been limited. A case where SPECT with Tc-99m dimercaptosuccinic acid (DMSA) better demonstrated a renal pseudotumor (a benign column of Bertin) compared to planar imaging is reported.