Impact of Immediate and Delayed Photo-activation of Self-adhesive Resin Cements on Bonding Efficacy and Water Uptake Under Simulated Pulpal Pressure.

This study investigated the effect of immediate versus delayed photo-activation on the bonding performance and water uptake of self-adhesive (SA) resin cements under simulated pulpal pressure (SPP). The occlusal dentin surface was exposed in 66 extracted third molars. Resin composite cylinders were cemented to dentin under SPP, with either RelyX Unicem 2 (RU) (3M Oral Care, St Paul, MN, USA) or Maxcem Elite (MC) (Kerr, Orange, CA, USA). Each cement group was equally divided into three groups (n=8 each) according to the time elapsed between placement and photo-activation: immediate activation (IM), 30-second delayed activation (D30), or 120-second delayed activation (D120). Shear bond strength (SBS) was measured, and the type of failure was determined using a stereomicroscope. Three additional samples from each experimental subgroup were used for confocal laser scanning microscopy (CLSM) analysis. A fluorescent dye solution was added to the pulpal fluid reservoir, then a CLSM was used to detect the dye distribution within the tooth-restoration interface. Two-way analysis of variance (ANOVA) and the Tukey post-hoc test were used to analyze the SBS results (α=0.05). D30 resulted in a significantly higher mean SBS in the two cement groups than IM and D120 (p<0.05). RU showed significantly higher SBS values than MC regardless of the time of light activation (p<0.05). RU showed less dye uptake confined to the cement-dentin interface compared to the MC groups, which showed dye uptake throughout the entire thickness of the cement layer and gap formation at the interface, especially in the D120 group. The 30-second photo-activation delay group significantly improved the bond strength of SA cements. Delaying the photo-activation to 120 seconds increased pulpal fluid uptake by SA cements and compromised the integrity of the bonded interfaces.

Effect Of Calcium Silicate, Sodium Phosphate, and Fluoride on Dentinal Tubule Occlusion and Permeability in Comparison to Desensitizing Toothpaste: An In Vitro Study.

This study compared the ability of a calcium silicate-, sodium phosphate-, and fluoride-based (CSSPF) toothpaste (TP) in promoting dentinal tubule occlusion and reducing dentin permeability with that of other commercially available antisensitivity TPs. Seventy-eight dentin discs (1.0±0.1 mm thick) were prepared from the midcoronal area and were treated with 37% phosphoric acid for 2 minutes; then they were randomly divided into six groups according to treatments: No treatment [positive control (PC)], entirely covered with nail varnish [negative control (NC)], hydroxyapatite (HAP)-containing TP [Desensin Repair (DES)], NovaMin-based [Sensodyne Repair & Protect (SEN)], CSSPF-based TP [Regenerate Advanced (REG)], sodium monofluorophosphate, potassium citrate, zinc citrate TP [Signal Sensitive Expert (SIG)]. Dentin permeability was tested by the dye percolation method (DP%). Scanning electron microscope (SEM) micromorphological and energy dispersive X-ray elemental analysis (EDX) of the dentin surfaces were done following each treatment. Results were analyzed using one-way analysis of variance (ANOVA) followed by Tukey post hoc test at a 95% confidence level (α=0.05). All the tested groups showed higher DP% than NC and lower percolation than the PC (p<0.05). REG and SIG were statistically comparable, and showed significantly lower DP% (p<0.05) than SEN and DES. None of the TPs tested was able to obliterate the lumen of the dentinal tubules (DT) completely. REG exhibited the highest weight percentage of calcium deposition, followed by SEN. Compared to the tested desensitizing TPs, CSSPF-based TPs demonstrated equal or less dentin permeability and better DT occlusion.

Effect of Preparation Depth on the Marginal and Internal Adaptation of Computer-aided Design/Computer-assisted Manufacture Endocrowns.

The aim of the study was to evaluate the effect of preparation depth and intraradicular extension on the marginal and internal adaptation of computer-aided design/computer-assisted manufacture (CAD/CAM) endocrown restorations. Standardized preparations were made in resin endodontic tooth models (Nissin Dental), with an intracoronal preparation depth of 2 mm (group H2), with extra 1- (group H3) or 2-mm (group H4) intraradicular extensions in the root canals (n=12). Vita Enamic polymer-infiltrated ceramic-network material endocrowns were fabricated using the CEREC AC CAD/CAM system and were seated on the prepared teeth. Specimens were evaluated by microtomography. Horizontal and vertical tomographic sections were recorded and reconstructed by using the CTSkan software (TView v1.1, Skyscan).The surface/void volume (S/V) in the region of interest was calculated. Marginal gap (MG), absolute marginal discrepancy (MD), and internal marginal gap were measured at various measuring locations and calculated in microscale (µm). Marginal and internal discrepancy data (µm) were analyzed with nonparametric Kruskal-Wallis analysis of variance by ranks with Dunn's post hoc, whereas S/V data were analyzed by one-way analysis of variance and Bonferroni multiple comparisons (α=0.05). Significant differences were found in MG, MD, and internal gap width values between the groups, with H2 showing the lowest values from all groups. S/V calculations presented significant differences between H2 and the other two groups (H3 and H4) tested, with H2 again showing the lowest values. Increasing the intraradicular extension of endocrown restorations increased the marginal and internal gap of endocrown restorations.

Effect of Thermocycling, Degree of Conversion, and Cavity Configuration on the Bonding Effectiveness of All-in-One Adhesives.

The aim of this study was to compare five all-in-one bonding agents with respect to microleakage, microtensile bond strength (µTBS), degree of conversion (DC) and the impact of cavity configuration. The materials tested were Adper Easy Bond, Clearfil S3 Bond, iBond, Optibond All-in-One, Xeno IV, and Adper Single Bond Plus as a control. The DC of each adhesive was measured on the surfaces of dentin discs (n=5) by attenuated total reflectance Fourier transform infrared spectroscopy. One hundred and forty-four extracted human molars were randomly divided and assigned to one of the five tested adhesives and the control group. The µTBS to dentin was measured on flat occlusal dentin with and without thermocycling and to the gingival floor dentin of class II cavities (n=8). All specimens were restored with Filtek Z250 resin composite. Class II samples were immersed in a 5% methylene blue dye solution for 24 hours, and microleakage was examined under a stereomicroscope. Micromorphological analysis of demineralized/deproteinized specimens was done using scanning electron microscopy. The DC and microleakage data were statistically analyzed by one-way analysis of variance (ANOVA) and µTBS data by two-way ANOVA followed by a Bonferroni multiple comparison post hoc test (α=0.05) and Weibull-distribution survival analysis. The relation between different variables and µTBS and microleakage was tested by the Pearson correlation coefficient and regression statistics. A moderate direct relation between DC and µTBS durability was found for all the adhesives tested. Significant wide variations exist among the results obtained for single-bottle adhesives tested regarding their µTBS and microleakage. Some of the all-in-one materials tested have shown significantly inferior results under a high C-factor or after aging. The use of these materials should be carefully considered.

Fracture resistance and microleakage of endocrowns utilizing three CAD-CAM blocks.

This study assessed marginal leakage and fracture resistance of computer-aided design/computer-aided manufacturing (CAD/CAM) fabricated ceramic crowns with intracoronal extensions into the pulp chambers of endodontically treated teeth (endocrowns) using either feldspathic porcelain (CEREC Blocks [CB], Sirona Dental Systems GmbH, Bensheim, Germany), lithium disilicate (e.max [EX], Ivoclar Vivadent, Schaan, Liechtenstein), or resin nanoceramic (Lava Ultimate [LU], 3M ESPE, St Paul, MN, USA).). Thirty extracted human permanent maxillary molars were endodontically treated. Standardized preparations were done with 2-mm intracoronal extensions of the endocrowns into the pulp chamber. Teeth were divided into three groups (n=10); each group was restored with standardized CAD/CAM fabricated endocrowns using one of the three tested materials. After cementation with resin cement, specimens were stored in distilled water at 37°C for one week, subjected to thermocycling, and immersed in a 5% methylene-blue dye solution for 24 hours. A compressive load was applied at 35 degrees to long axis of the teeth using a universal testing machine until failure. Failure load was recorded, and specimens were examined under a stereomicroscope for modes of failure and microleakage. Results were analyzed using one-way analysis of variance and Bonferroni post hoc multiple comparison tests (α=0.05). LU showed significantly (p<0.05) higher fracture resistance and more favorable fracture mode (ie, fracture of the endocrown without fracture of tooth) as well as higher dye penetration than CB and EX. In conclusion, although using resin nanoceramic blocks for fabrication of endocrowns may result in better fracture resistance and a more favorable fracture mode than other investigated ceramic blocks, more microleakage may be expected with this material.

Effect of C-factor on microtensile bond strengths of low-shrinkage composites.

UNLABELLED: This study evaluated the microtensile bond strength (µ-TBS) of low-shrinkage composites with their corresponding adhesive systems, Filtek Silorane/Silorane adhesive (SIL, 3M ESPE AG, Seefeld, Germany) and Aelite LS/One-Step Plus (AL, BISCO Inc, Schaumburg, IL, USA) in cavities with different C-factors. Filtek Z250/Adper Single Bond Plus (Z, 3M ESPE, St Paul, MN, USA) was used as a control. METHOD: Standardized Class I cavities were prepared in extracted human molars after removing occlusal enamel. Cavities were assigned into six different C-factors by applying nail polish to four walls, three walls, two walls adjacent to each other, two walls opposite to each other, one wall, or no walls. Resin composites with their corresponding adhesive systems were applied according to manufacturer instructions. Specimens were sectioned to obtain four rectangular beams from the center of the restorations and µ-TBS was measured. Data were analyzed by Weibull survival analysis. Shrinkage stresses of the resin composites were determined after 30 minutes from the start of light-curing using a tensometer testing machine. Flexure elastic modulus was determined using standard procedures, in accordance with ISO 4049. Data for shrinkage stress and elastic modulus were analyzed by one-way analysis of variance followed by a Tukey multiple-comparisons test (p<0.05). RESULTS: µ-TBS of both SIL and AL were not affected by different C-factors; however, the bond strength of Z decreased significantly when the C-factor increased. Shrinkage stress results were 0.94 ± 0.1, 1.79 ± 0.18, and 2.14 ± 0.23 MPa for SIL, AL, and Z, respectively. The flexural modulus of both the SIL and the AL was significantly lower than that of Z. CONCLUSIONS: Increasing C-factor did not negatively affect the bond strength of low-shrinkage composites.

[Computed tomography following extracorporeal shockwave lithotripsy of the kidneys. III. A prospective CT study of 105 patients and a 3-year follow-up of 23 patients using CT and 99mTc-MAG3 clearance]. / Computertomographie nach extrakorporaler Stosswellenlithotripsie (ESWL) der Nieren.Teil III: Prospective CT-Untersuchung bei 105 Patienten und Drei-Jahres-Kontrolle bei 23 Patienten mit CT und seitengetrennter 99mTc-MAG3-Clearance.

In 105 patients CT studies were done prospectively after renal ESWL with a second generation lithotripter. 33 (31%) of the patients had renal oedema (n = 8), renal (n = 20) or extrarenal (n = 31) bleeding. Three of the 23 patients who had a three year follow-up had chronic renal changes, 10 had renal stones. As blunt renal trauma can be the cause of renal hypertension a longterm follow-up is necessary in ESWL patients, particularly if there was renal bleeding after treatment. Further studies are needed to determine the exact risk of renal hypertension after ESWL.

[99m-Technetium-mercaptoacetyltriglycine (MAG3) for the demonstration of the kidney changes following extracorporeal shockwave lithotripsy. A prospective study of 117 patients]. / 99mTechnetium-Mercaptoacetyltriglycin (MAG3) zum Nachweis von Nierenveränderungen nach extra-korporealer Stosswellenlithotripsie. Eine prospektive Untersuchung bei 117 Patienten.

Extracorporeal shock wave lithotripsy (ESWL) has become the treatment of choice for urinary calculi. 117 patients were studied prospectively with 99mTc mercaptoacetyltriglycine (MAG3) before and after ESWL. 79 (66%) of the 119 kidneys treated had abnormal findings. Of these 63/119 (53%) had abnormal scans. 41 (65%) had focal lesions with a delayed intrarenal transport. The remaining 22 had a diffuse delay of intrarenal transport. A loss of relative renal function of 3% and more compared to the pretreatment values was observed in 50/119 (42%) patients. 99mTc MAG3 should be done routinely together with radiologic tests (CT or MRI) before and after ESWL to select the patients at risk for post ESWL hypertension.

The buccal mucosal graft for urethral reconstruction: a preliminary report.

Autologous buccal mucosa as a substitute for urethral epithelium was studied in 2 dogs and used in 6 patients with difficult urethral reconstruction problems. The indications for an operation in these patients were failed hypospadias repairs with limited skin in 3, severe structure disease after hypospadias repair in 1, a short urethra in 1 and epispadias in 1. Three urethral fistulas and 1 meatal stenosis occurred in 3 patients. No urethral stricture or diverticulum was noted, and the final outcome was good functionally and cosmetically in all patients. This technique is useful for urethral reconstruction when local skin is not available.

Characterization of conservatively resected renal tumors using automated image analysis DNA cytometry.

The DNA histograms of 57 conservatively resected renal tumors were studied using automated image analysis DNA cytometry (Leytas II). Forty-nine of the analyzed tumors were renal cell carcinomas, six were oncocytomas, one was an angiomyolipoma, and one was a renal cell adenoma. On the basis of their DNA histograms, diploid, tetraploid, and aneuploid tumors could be distinguished. Aneuploid tumors could be subtyped further according to the DNA content of the stem cell line as hyperdiploid, hypertriploid, or hypertetraploid. Eight of the tumors were characterized by a combination of diploid and hypertriploid stem cell lines. During a mean follow-up of 5 years, only the two patients with a pure hypertriploid tumor died of distant metastases. These results indicate that automated DNA image analysis cytometry is able to differentiate among several types of renal tumors with obviously different prognoses.

Surgical aspects of urolithiasis in children.

Operative management of renal calculi has changed radically in the last decade. New operative techniques, the use of intra-operative ultrasound and Doppler sonography have even made possible the removal of complete staghorn calculi in short and kidney-preserving procedures. The introduction of percutaneous nephrolithotomy and stone extraction using a specially designed ureteroscope and, above all, the clinical application of extracorporeal shock wave lithotripsy have made stone surgery less invasive and have provided a higher rate of preservation of kidney function.

[Computed tomography after extracorporeal shockwave lithotripsy (ESWL) of the kidneys. II. A correlation with the histopathologic findings 3 weeks later in an animal experiment]. / Computertomographie nach extrakorporaler Stosswellen-Lithotripsie (ESWL) der Nieren. Teil II: Korrelation mit histopathologischen Befunden nach 3 Wochen im Tierexperiment.

In a pig model, 13 kidneys were treated with a second generation lithotripter and examined by CT immediately and three weeks after ESWL. 9 (69%) acute traumatic lesions were seen in CT without, and 10 (77%) in CT with contrast in the 13 treated kidneys. After 3 weeks only 1 residual lesion persisted in CT contrast studies. On the histopathologic specimens residuals of bleeding were found in 3 (23%) of the 13 kidneys treated, which could not be seen in CT studies. CT is accurate in monitoring acute traumatic renal lesions after ESWL, but appears less reliable in chronic ones. Three weeks after ESWL traumatic renal lesions show marked regression.

Extracorporeal shock wave lithotripsy of urinary calculi: experience in treatment of 3,278 patients using the Siemens Lithostar and Lithostar Plus.

Between March 1986 and June 1989, 3,278 patients with upper urinary tract calculi were treated at our medical center with the Lithostar lithotriptor. The stones were located in the calices in 41.9% of the cases, renal pelvis in 25.7% and ureter in 32.4%. Perirenal hematoma was noted in 0.5% of the patients but this resolved spontaneously within a few days. Auxiliary procedures were performed in 37.3% of the cases, including Double-J stent and ureteral catheter in 26.8%, ureterorenoscopy in 2.1%, percutaneous nephrostomy in 1.6%, Zeiss loop in 4.3% and percutaneous nephrolithotripsy in 3.5%. Of the treatments 83.1% were performed without general or regional anesthesia. Followup after 3 months showed a 63.8% rate free of stone. The Lithostar upgraded with the overhead lithotripsy module is called Lithostar Plus. A total of 25 patients with upper urinary stones underwent treatment with the overhead module. Initial experience revealed fragmentation of stones after the first session in 20 patients, while a second session was necessary in 5. Analgesic sedation was used in 4 patients in whom a Double-J stent was inserted.

[Computed tomography following extracorporeal shockwave lithotripsy (ESWL) of the kidneys. I: Correlation with acute histopathological findings in experimental animals]. / Computertomographie nach extrakorporaler Stosswellen-Lithotripsie (ESWL) der Nieren. Teil I: Korrelation mit akuten histopathologischen Befunden im Tierexperiment.

In an experimental study on pigs, 28 stone-free kidneys were treated with a second generation lithotripter. Histologically, acute bleeding was seen after ESWL in 23 (82%) of the 28 treated kidneys. CT studies before and after contrast were correct in 20/28 (74%) cases. It was shown that extracorporeal shock waves cause renal bleeding that is only partially detected by computed tomography. It can be concluded that the CT findings seen in a high percentage of renal stone patients after ESWL represent bleeding. The incidence of renal bleeding after ESWL and thus the possible risk of hypertension has obviously been underestimated so far in clinical studies.

Hypertension and impotence.

In a group of 472 impotent patients who were evaluated with pharmacologic duplex sonography, 117 patient (24.8%) had a history of hypertension, 26 of them (22.2%) for more than 10 years. Objective data about the changes in pulsation, diameter and blood flow velocity of the penile arteries after papaverine injection and the resulting erectile response allowed indirect assessment of the penile venous function. Varying degrees of impaired arterial function were diagnosed in 85% of the patients. The duration of hypertension had less deteriorating effects on the penile arterial system than second risk factors such as diabetes mellitus (n = 31) or smoking (n = 26). Patients on antihypertensive medication (n = 88, 75.2%) demonstrated a worse arterial response to papaverine than those without medication (n = 29, 24.8%). The best vascular response to papaverine injection was found in patients taking a combination of beta-blockers and vasodilators (n = 6), whereas thiazides either taken alone or in combination (n = 51, 60%) seem to have a deteriorating effect on arterial function. However, the arterial response did not correlate with the ability to achieve 'full erection' after intracavernous papaverine injection. Clinical experience confirms that certain antihypertensive drugs affect not only the blood pressure, but also compliance of the erectile tissue resulting in a functional venous leak. This may impair erectile function as much as arteriosclerotic changes of the vascular system secondary to hypertension.