[Effect of decontaminating solutions on titanium surface: an in vitro study of human epithelial cell culture]

INTRODUCTION

The effects of three different decontaminating solutions in clinical use for peri-implantitis therapy on the chemical structure and surface roughness of commercially pure (CP) Ti were investigated. A further aim was to survey the response of the biological environment to these changes, by examining the attachment and proliferation of human epithelial cells after treatment of the Ti surfaces with these solutions.

MATERIALS AND METHODS

CP (grade 4) machined titanium discs (CAMLOG Biotechnologies AG, Switzerland) were treated with 3% H2O2 (5 min), saturated citric acid (pH = 1; 1 min) or chlorhexidine gel (CHX, 5 min). The surface properties were followed through the use of X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The epithelial cell attachment and proliferation was examined by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and bicinchoninic acid (BCA) protein-content assays.

RESULTS

XPS showed an intact TiO2 layer on each sample and CHX was adsorbed by the surface, as C-O and/or C=O bond formation was revealed. AFM results gave no significant changes in the roughness after treating the surfaces with the cleaning solutions. While MTT and BCA assays did not show significant differences in epithelial cell attachments, the cell proliferation was significantly increased after H2O2 treatment as compared to CHX (not shown by BCA assays).

CONCLUSIONS

The applied decontaminating agents do not damage the Ti surface. H2O2 can be used effectively in decontaminating the implants affected by peri-implantitis, as the human epithelial cell growth was improved, in contrast with CHX.

Effects on titanium implant surfaces of chemical agents used for the treatment of peri-implantitis

The treatment of peri-implantitis, which causes tissue deterioration surrounding osseointegrated implants, involves surface decontamination and cleaning. However, chemical cleaning agents may alter the structure of implant surfaces. We investigated three such cleaning solutions. Commercially pure (grade 4) machined titanium discs (CAMLOG Biotechnologies AG, Switzerland) were treated with 3% H(2)O(2) (5 min), saturated citric acid (pH = 1) (1 min) or chlorhexidine gel (5 min), and their surface properties were examined by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Human epithelial cell attachment (24-h observation) and proliferation (72-h observation) were investigated via dimethylthiazolyl-diphenyltetrazolium bromide (MTT) and bicinchoninic acid (BCA) protein content assays. AFM revealed no significant difference in roughness of the three treated surfaces. XPS confirmed the constant presence of typical surface elements and an intact TiO(2) layer on each surface. The XPS peaks after chlorhexidine gel treatment demonstrated C-O and/or C=O bond formation, due to chlorhexidine digluconate infiltrating the surface. MTT and BCA assays indicated similar epithelial cell attachments in the three groups; epithelial cell proliferation being significantly higher after H(2)O(2) than after chlorhexidine gel treatment (not shown by BCA assays). These agents do not harm the Ti surface. Cleaning with H(2)O(2) slightly enhances human epithelial cell growth, in contrast to chlorhexidine gel.

[Vertigo--comorbidity with psychiatric disorders]

Vertigo is one of the most common symptom and complaint in the clinical practice. The differential diagnosis can only be attained by a careful interdisciplinary way of thinking and activity, given the fact that the vestibular, neurological and psychiatric disorders--considered as pathogenic factors--are being present simultaneously in triggering the symptoms, and there can be overlaps between the certain pathological processes. The author deals with the co-morbidity of the vertigo and the psychiatric symptoms--anxiety, panic-disorder--, pointing out the common neurobiological and neurophysiological factors in the background of the symptoms, emphasizing the importance of the SSRI-s in the restoration of the serotonerg dysfunction.

Antiinflammatory effect of BPC 157 on experimental periodontitis in rats

The pentadecapeptide BPC 157 has been shown to have anti-inflammatory and wound healing effects on multiple target tissues and organs. The purpose of the present study was to investigate the effect of BPC 157 on inflammation and bone resorption in experimental periodontitis in rats. First the acute effect of BPC was tested on gingival blood flow by laser doppler flowmetry. Then periodontitis was produced by a silk ligature placed around the lower left first molar. Rats were treated with BPC 157 (once daily for 12 days) or vehicle. At day 13, the gingivomucosal tissues encircling the molars were removed on both sides. Inflammation was assessed by Evans blue plasma extravasation technique and by histology. Alveolar bone loss was analyzed by microCT. BPC 157 had no effect on gingivomucosal blood flow. Twelve day ligature caused a significantly increased Evans blue extravasation in the gingivomucosal tissue, histological signs of inflammation, and alveolar bone destruction. BPC 157 treatment significantly reduced both plasma extravasation, histological alterations and alveolar bone resorption. In conclusion, systemic application of BPC 157 does not alter blood circulation in healthy gingiva. Chronic application of the peptide has potent antiinflammatory effects on periodontal tissues in ligature induced periodontitis in rats. Taken together, this proof of concept study suggests that BPC 157 may represent a new peptide candidate in the treatment of periodontal disease.

[Streptococcus mutans colonization on titanium surfaces treated with various fluoride-containing preventive solutions]

Fluoride is a reductive agent and may modify the oxide layer of titanium (Ti) in the transgingival region of dental implants. The low pH and the high fluoride concentration of prophylactic mouthwashes and gels (used in caries prevention) may play a role in this phenomenon. Our main goal was to examine whether changes on the surface structure of Ti caused by high fluoride concentration and acidic pH alter the adherence and the colonization of bacteria. Polished commercially pure Ti discs (CP grade 4, Camlog, Biotechnologies AG, Switzerland) were used in the study. Each sample was treated for 1 hour with one of the solutions: mouthwash containing 0.025% (250 ppm) fluoride, a gel containing 1.25% (12500 ppm) fluoride, and a solution of 1% NaF (3800 ppm fluoride), pH 4.5. The surface structure of the discs was analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The colonization of Streptococcus mutans was studied by scanning electron microscope (SEM) after a 5-day incubation period. The roughness of the treated sample surfaces (Ra), as revealed by AFM measurements, increased 1.3 times for the gel and the mouthwash, and approximately seven folds for the 1% NaF solution, as compared to the control surface. The high fluoride concentration and acidic pH of the gel and the 1% NaF solution resulted in a strong corrosion and a modification of the composition of the Ti surface. The XPS spectra showed the formation of a fluoride containing complex (Na2TiF6) bound strongly to the surface. A correlation was revealed between the roughness of the surface and thickness and maturity of the S. mutans bacterial colonies developed on the modified Ti surface. High fluoride concentration and acidic pH increased the roughness of the Ti surface. Bacterial biofilm colonization on this rough surface proved to be more mature. The amount of bacteria was increased due to the changes in the surface caused by fluoride treatment. The present study indicates that high fluoride concentration in an acidic pH environment may affect the development of a healthy transgingival epithelial junction on the Ti surface. This work was supported by the SIMI-NAS Project of the 5th FWP of the European Commission (Growth Program, GRD3-2001-61801), the Hungarian Ministry of Economy and the EC (GVOP-3.2.1.-2004-04-0408/3.0), the Hungarian Ministry of Health (ETT, 434/2006), and the Hungarian Scientific Research Fund (OTKA F-68440).

[Vertigo in neurological diseases]

Peripheral and central vestibular syndromes are characterized by the combination of the four symptoms such as: vertigo, nystagmus, imbalance and nausea. Vertigo is the disturbance of the cortico-spatial orientation. Nystagmus is regarded as a secondary symptom caused by direction specific disequilibrium of the vestibulo-ocular reflex. Imbalance is caused by the abnormal activation of vestibulo-spinal pathways. Nausea is due to the activation of the medullary vomiting center. It is important that clinicians can establish an adequate diagnosis and differentiate vertigo and dizziness. The author--without the aim of completeness--discusses the types of vertigo caused by the most important disorders of the central nervous system, emphasizing the role of general practitioners in the diagnostic and therapeutic algorhytm.

A pilot study of Cerasorb and Bio-Oss enhanced new bone formation in animal model

The aim of this pilot investigation was to develop a new animal model for studying the effects on osteogenesis of agents used in the guided bone regeneration technique. As test material, a mixture of two osseoconductive materials with different physico-chemical characteristics was used. One component of the mixture was Bio-Oss, a bovine hydroxyapatite; the other was Cerasorb, a synthetic tricalcium phosphate. The mixture consisited of 50 volume percent of Bio-Oss and 50 volume percent of Cerasorb. In in vivo pilot experiment, bone wounds were prepared in the proximal third of both femurs of rabbits. A Cerasorb + Bio-Oss mixture was inserted on the test side and the same amount of sterile buffered physiological solution on the control side. After healing for 4 weeks, the bone segments were embedded and cut without decalcification, using the Exact cutting and grinding system. The density of the newly-formed bone was evaluated histomorphometrically. On the Cerasorb + Bio-Oss test side the bone density was almost 1.5 times higher than that on the control side. These results demonstrated that the applied animal model is appropriate for investigation of the effects on osteogenesis of biocompatible graft materials such as Bio-Oss and Cerasorb.

[Prosthetic rehabilitation of an epilepsy patient with dental implants. Case report]

According to epidemiologic data patients with epilepsy generally have more caries, more missing teeth and worse periodontal status than the normal population. Epilepsy patients have a great risk of injury during their seizures or aspiration of foreign bodies such as removable dental prosthesis or fragments of prosthesis. Fixed dental replacements are therefore recommended to reduce this risk. In cases where the anatomic restrictions enable only a conventional removable prosthesis, an implant prosthetic treatment offers helpful alternative for the epileptic patient. The implant prosthetic treatment of a 48-year-old epileptic patient is presented. After inserting six dental implants into the lower jaw, three short span bridges were fabricated. The surgery was carried out under local anesthesia in the routine way. A bite plate was made for night use to avoid the crack of the ceramic surfaces during any possible seizure.

[The effect of fluorides on the surface structure of titanium implants]

The high fluoride concentration and the acidic pH in tooth-paste used to prevent caries may modify the surface structure of implants made of titanium. Oxidative agents thicken and condense the titanium-dioxid layer on the surface of titanium and improve its stability against corrosion effects, while reductive agents like fluoride may have the opposite effect and attack this layer. The aim of the present work was to study the effects of fluoride containing toothpaste and gel on the titanium dioxid layer of titanium. The surfaces of the titanium (commercial pure grade I.) discs were treated with toothpaste and gel containing 0.125 % and 1.25 % fluoride, respectively. The changes in the surface structure were analyzed by atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). Our results demonstrated that fluoride strongly binds to the titanium surface and modifies its structure in case of fluoride containing gels.

[Quantitative and qualitative comparison of the maxillary bone regeneration after beta-tricalcium phosphate and autogenous bone implantation]

Graft insertion can effectively enhance the regeneration of debilitated bone. The effects of an alloplastic bone-replacing material, beta-tricalcium phosphate (Cerasorb), and of autogenous bone graft were compared. In 17 edentulous patients, the maxillary sinus floor was extremely atrophied to such an extent that implant placement was impossible. The Schneiderian membrane was surgically elevated bilaterally by insertion of Cerasorb (experimental side) and autogenous bone graft (control side). After surgery, the recovery was followed clinically and radiologically. After 6 months, 68 bone cylinders were excised from the grafted areas and implants were inserted into their places. The bone samples were embedded into resin, and the osteointegration of the grafts was studied histologically. Trabecular bone volume (TBV) and trabecular bone pattern factor (TBPf) were quantified by histomorphometry. Cerasorb proved to be an effective bone-replacing material with osteoconductivity; it was capable of gradual disintegration, thereby providing space for the regenerating bone. The new bone density was not significantly different on the experimental and control sides (32.4 +/- 10.9% and 34.7 +/- 11.9%, respectively). However, the graft biodegradation was significantly slower on the experimental side than on the control side. The TBPf value was lower on the control side than on the experimental side (-0.53 +/- 1.7 mm(-1) and -0.11 +/- 1.4 mm(-1), respectively); but this difference was not significant. Six months after insertion of the grafts, the bone of the augmented sinus floor was strong and suitable for anchorage of dental implants, irrespective of whether autogenous bone or Cerasorb particles had been applied.

[The electrochemical behavior of titanium and dental casting in modelling oral conditions]

The electrochemical behavior of titanium and dental casting alloys in modelling oral conditions With applying dental implants in the oral cavity the direct contact of various metals (titanium and other casting alloys) is unavoidable. Considering the electrolyte characteristic of the saliva, the chances are given that electrochemical processes might occur under such circumstances. The aim of this study was to investigate the electrochemical behavior of titanium and other dental alloys being in direct contact with the oral environment. Nickel-chromium, cobalt-chromium, high palladium content and gold alloys as well as CP grade I titanium cast samples respectively were involved in the study. Test models were made from these metals. As an electrolyte solution (set to pH 4) artificial saliva and 0.9 % NaCl solution were used. The type and the rate of corrosion were assessed with laboratory immersion test and electrochemical polarization method. In case of polarization method a three-electrode measuring-cell was applied. Laboratory exposure tests revealed that titanium resisted corrosion; there was no sign of corrosion at all. The high palladium content alloy and gold alloy behaved similarly. The nickel-chromium and cobalt-chromium alloys showed some signs of corrosion, especially in sites with damaged surface or inhomogeneities on the surface. Results of the laboratory electrochemical experiments correlated with immersion studies graphically illustrated in the paper.

[Neurophysiological background of pain in the orofacial area: review of the literature]

The article presents an overview on the peripheral and central neural mechanisms underlying pain in the orofacial area. First a definition of pain and a description of general aspects of orofacial pain are presented. Characteristics of acute and chronic pain are also described. The study highlights the sense organs, the molecular mechanisms and categories of primary afferents involved in peripheral events of orofacial pain. After describing the brain-stem nuclei participating in trigeminal pain and their functional role, primary afferents involved in nociceptive sensation from the tooth pulp, explanations of dentinal sensitivity and differences between the brain-stem endings of primary afferents among different species are discussed in details. The role of higher brain centres, with a special emphasis on the thalamus and somatosensory cortex in the development of orofacial pain sensation is considered. The last section provides a review about how the activities of nociceptive neurons are controlled by higher brain centres and neurochemicals involved in pain transmission.

Maxillary sinus floor grafting with β-tricalcium phosphate in humans: density and microarchitecture of the newly formed bone

OBJECTIVES

Graft insertion can effectively enhance the regeneration of debilitated bone. The effects of an alloplastic bone-replacing material, beta-tricalcium phosphate (Cerasorb), and of autogenous bone graft were compared.

MATERIALS AND METHODS

In 17 edentulous patients, the maxillary sinus floor was extremely atrophied to such an extent that implant placement was impossible. The Schneiderian membrane was surgically elevated bilaterally by insertion of Cerasorb (experimental side) and autogenous bone graft (control side). After surgery, the recovery was followed clinically and radiologically. After 6 months, 68 bone cylinders were excised from the grafted areas and implants were inserted into their places. The bone samples were embedded into resin, and the osteointegration of the grafts was studied histologically. Trabecular bone volume (TBV) and trabecular bone pattern factor (TBPf) were quantified by histomorphometry.

RESULTS

Cerasorb proved to be an effective bone-replacing material with osteoconductivity; it was capable of gradual disintegration, thereby providing space for the regenerating bone. The new bone density was not significantly different on the experimental and control sides (32.4+/-10.9% and 34.7+/-11.9%, respectively). However, the graft biodegradation was significantly slower on the experimental side than the control side. The TBPf value was lower on the control side than on the experimental side (-0.53+/-1.7 and -0.11+/-1.4 mm(-1), respectively), but this difference was not significant.

CONCLUSIONS

Six months after insertion of the grafts, the bone of the augmented sinus floor was strong and suitable for anchorage of dental implants, irrespective of whether autogenous bone or Cerasorb particles had been applied.

Structural Characterization of Self-Assembled Polypeptide Films on Titanium and Glass Surfaces by Atomic Force Microscopy

Chemically modified biomaterial surfaces (titanium and glass) covered with polyelectrolyte self-assembled films formed by the alternating adsorption of cationic poly-L-lysine (PLL) and anionic poly-L-glutamic acid (PGA) were structurally characterized by atomic force microscopy. Complementary information concerning the thickness and layer-by-layer growth of the films was provided by optical waveguide light-mode spectroscopy. The frequently used ex situ and the rarely used in situ build-up methods were compared. Important aspects of the industrial applicability of these films, their stability in time, and possible differences in their morphology were investigated. The films revealed a granular pattern, with grain diameters of 270 +/- 87 nm for glass (up to 8 bilayers) and 303 +/- 89 nm for titanium (up to 10 bilayers), independently of the build-up procedure. Both surfaces displayed a rehydration capability, the titanium surface exhibiting a better stability in time. The high roughness values observed at acidic or basic pH are related to the degree of ionization of PGA and PLL.

[Dizziness-vertigo. Alarming symptoms in vertebrobasilar ischemia. Part II]

Dizziness and vertigo--like headache--are the most common complaints which lead patients to visit the doctor. In spite of the headache--which may be primary (e.g. migraine) or symptomatic--dizziness and vertigo do not appear to be a separate nosologic entity but rather the symptoms of several neurological disorders. For differential diagnosis, interdisciplinary thinking and action is needed because the vestibular, neurological and psychiatric disorders might have a common role in the development of symptoms and further overlapping can also occur. The vascular disorders of the vertebrobasilar system are discussed in detail in this review. The importance, occurrence and causes of vertigo as a warning symptom is in the focus. The author draws attention to life-threatening conditions with acute onset in cases of the posterior scale ischemia and emphasizes the importance of the correct and early diagnosis. The author tries to clear up the nihilistic aspect in treating of stroke and stresses the necessity of thrombolysis and interventional radiological procedures which may be the only chance for the recovery of the patients. The pharmacological prevention of recurrent vascular events is also important and obligatory for the clinicians.

[Surface modifications of titanium implant material with excimer laser for more effective osseointegration]

The biointegration of dental and orthopaedic implants depends mainly on the morphology and physical-chemical properties of their surfaces. Accordingly, the development of the desired microstructure is a relevant requirement in the bulk manufacture. Besides the widely used sandblasting plus acid etching and plasma-spray coating techniques, the laser surface modification method offers a plausible alternative. In order to analyze the influence of the laser treatment, the surfaces of titanium samples were exposed to excimer laser irradiation. The aim of this study was to develop surfaces that provide optimal conditions for bone-implant contact, bone growth, formation and maintenance of gingival attachment. For this purpose, holes were ablated on the surface of samples by nanosecond (18 ns, ArF) and also sub-picosecond (0,5 ps, KrF) laser pulses. Using pulses of ns length, due to melt ejection, crown-like protrusions were formed at the border of the holes, which made them sensitive to mechanical effects. To avoid these undesirable crown-like structures ultrashort KrF excimer laser pulses were successfully applied. On the other hand, titanium samples were laser-polished in favour of formation and connection of healthy soft tissues. Irradiation by a series of nanosecond laser pulses resulted in an effective smoothening as detected by atomic force microscopy (AFM). By inhibiting plaque accumulation this favours formation of gingival attachment. X-ray photoelectron spectroscopy (XPS) studies showed that laser treatment, in addition to micro-structural and morphological modification, results in decreasing of surface contamination and thickening of the oxide layer. X-ray diffraction (XRD) analysis revealed that the original alpha-titanium crystalline structure of the laser-polished titanium surface was not altered by the irradiation.

[Alarming symptoms in vertebrobasilar circulatory disorders. Part I]

Dizziness and vertigo--like headache--are the most common complaints which leads patients to visit the doctor. In spite of the headache--which may be primary (e.g. migraine) or symptomatic--dizziness and vertigo do not appear to be a separate nosologic entity but rather the symptoms of several neurological disorders. For differential diagnosis, interdisciplinary thinking and activity is needed because the vestibular, neurological and psychiatric disorders might have a common role in the development of symptoms and further overlapping can also occur. The vascular disorders of the vertebrobasilar system are discussed in detail in this review. The importance, occurrence and causes of vertigo as a warning symptom is in the focus. The author draws attention to life-threatening conditions with acute onset in cases of the posterior scale ischemia and emphasizes the importance of the correct and early diagnosis. The author tries to clear up the nihilistic aspect in treating of stroke and stresses the necessity of thrombolysis and interventional radiological procedures which may be the only chance for the recovery of the patients. The pharmacological prevention of recurrent vascular events is also important and obligatory for the clinicians.

Surface modifications induced by ns and sub-ps excimer laser pulses on titanium implant material

Medical implants used in oral and orthopaedic surgery are mainly produced from titanium. Their biological behaviour, e.g. osseointegration, essentially depends on both the chemical composition and the morphology of the surface. Modifications achieved by excimer laser irradiation of titanium samples were investigated in order to improve their surface characteristics so as to facilitate biointegration. To enlarge the effective interfacial area of bone-implant contact, holes were ablated by laser pulses of ns or sub-ps length. During ns ablation, crown-like projecting rims formed around the borders of the holes. Ultra-short (0.5ps) KrF excimer laser pulses were successfully applied to avoid these undesirable formations. Since a smooth dental implant surface is necessary to maintain a healthy connection with the soft tissues, laser polishing of samples was investigated, too. Irradiation with a series of ns laser pulses resulted in effective smoothing, as measured with atomic force microscope. X-ray photoelectron spectroscopy analysis of the laser-polished titanium surface revealed that laser treatment led to a decrease of the surface contamination and in thickening of the oxide layer. X-ray diffraction measurements demonstrated that the original alpha-titanium crystal structure was preserved.

[Formation of crystalline calcium phosphate coating on the titanium dioxide layer of dental implants' surface]

Production of octacalcium phosphate crystals on the surface of titanium dioxide particles was achieved at high concentration of titania particles. Optimising the speed of addition of the reagents in the process of crystal growth in heterogeneous nucleation reaction led to reproducible OCP crystal structure on the particle surface. The crystal structure of OCP was investigated by SEM, XRD and FTIR methods. The same crystallization process on the surface of metallic titanium plates did not result in formation of OCP crystals. The evaporated titanium layers on a glass surface and titanium plates without excimer laser treatment did not bond calcium phosphate at any rate. SEM investigations imply that the surface layer of titanium plates changes radically due to laser beam treatment, likely because of oxidation of titanium in the process of evaporation followed by deposition back onto the surface. The calcium phosphate formation on these oxidised titanium plates could be observed by SEM. It can be concluded, that for OCP-formation on titanium metal surface it is necessary to form a thick oxide layer, as the native oxide layer in the case of non-treated titanium substrates did not bound the calcium phosphate, while formation of calcium phosphate could be reached on the laser-treated surface.

[Prosthetic rehabilitation of cleft palate patients with fixed partial dentures]

Treatment of cleft palate patients demands a well coordinated work of medical and dental specialists. In spite of the surgical and orthodontic therapy a prosthetic rehabilitation is often necessary because of missing teeth, maxillary hypoplasia, malocclusion and palatal defects. The prosthetic phase begins immediately after the orthodontic treatment. In this way the fixed partial denture replaces the retention appliance and stabilizes the achieved status. The aim of the prosthetic treatment is to improve the function of the masticatory apparatus, speech and aesthetic appearance of the patient. An important task of the prostheses is to support and lift up the upper lip and the base of the nose. There are several factors, which make the treatment difficult, like underdeveloped and collapsed maxillary arch, retrognath position of the maxilla, missing alveolar ridge, defects of the bone and mucosa, scars and stiffness of the upper lip. The maintenance of the oral hygiene with the fixed restorations is often difficult because of the stiffness of the upper lip, therefore the design of the pontic is very important especially in the cases, when the missing processus alveolaris has to be replaced in order to improve the harmony of the face.

[Experience with intra-arterial thrombolysis in patients with acute stroke]

The authors report on their results with local intraarterial thrombolysis in four patients.

PATIENTS

Three patients suffered from vertebrobasilar artery occlusion, and one from carotid-T occlusion. All were treated with local intraarterial thrombolysis by a joint team of neurologist, neuroanaesthesist and interventional neuroradiologist in the stroke-department of St. Stephen Municipal Hospital in collaboration with National Institute of Neurosurgery. Selection of patients suitable for successful intraarterial thrombolysis has to be done in the neurological department with help of ultrasound and neurological examination and CT scan. Patients were transferred to the therapeutic angiosuit and interventional treatment was initiated immediately upon establishing the diagnosis. At least one million units of urokinase was infused directly into the embolus in each case.

RESULTS

Complete recanalisation was achieved in three of the four cases. That was associated with full recovery in two patients, in whom good collateral circulation and no signs of atherosclerotic lesions were found prior to treatment. Another patients has died despite of full recanalisation of the basilar artery. One patient survived after partial recanalisation of bilateral vertebral artery occlusion with mild residual tetraparesis.

CONCLUSION

Local intraarterial thrombolysis is effective and is associated with good clinical outcome in properly selected patients. Careful and accurate ultrasound diagnostics of the site of occlusion plays a significant role in proper patient selection. Although difficult, acute intraarterial thrombolysis can be organized in a timely fashion even utilizing the required facilities in two different institutions, providing that all efforts is being made by each party for the fast diagnosis and treatment initiation.

Comparative analysis of pulpal circulatory reaction to an acetone-containing and an acetone-free bonding agent as measured by vitalmicroscopy

Despite great progress in the production of new dental polymers, application of these products is still controversial. The unlined utilization of cytotoxic adhesive materials on pulpal dentin can adversely influence the pulp, leading to alterations in local microcirculation that can be an early sign of pathological changes. In a previous study by the authors, the effect of an acetone-free bondmaterial was examined on the vascular diameter of pulpal vessels by means of vitalmicroscopy. In this study, experiments comparing experimental data provided by an acetone-containing bondmaterial to these earlier findings with acetone-free ones have been performed. Thirty male Sprague-Dawley rats (weighing 333+/-9 g) were used for this investigation. The first lower incisor was prepared for vitalmicroscopy. Changes in vessel diameter were recorded prior to and 5, 15, 30 and 60 minutes after the investigated materials (Scotchbond Multi-Purpose Dental Adhesive System or Prime & Bond 2.1) were administered on dentin as recommended by the manufacturer. In control rats (saline administration), the vessel diameter was stable during the experiment. In the presence of acetone-free bondmaterial (Scotchbond), the vessel diameter was increased during the experimental period in relation to the baseline (12.15+/-2.85%; 16.36+/-2.39%; 14.16+/-3.48%; 12.12+/-3.72%). In the presence of acetone-containing bondmaterial (Prime & Bond 2.1), a similar result was observed (10.56+/-2.27%; 16.13+/-2.94%; 17.88+/-2.54%; 14.54+/-3.16%). The differences between the control values and those registered with test groups were significant (p<0.05; ANOVA). There was no significant difference among the test groups. The results of this study suggest that dental bond materials applied on a very thin layer of dentin may affect the blood supply to the dental pulp. However, no stasis or prestasis has been detected, indicating a possible reversible effect. The authors could not show any statistical difference between the vasodilatation caused by the acetone-containing and the acetone-free bond material.

[Model investigation of push-out test used for quantitative evaluation of dental implant osseointegration]

A frequently used method for quantitative evaluation of implant-bone interface strength is the push-out test. The objective of the authors' study was to determine the effect of implants' geometric characteristics on the results of push-out method. The degree of osseointegration is determined by a complicated interaction of mechanical, biological and chemical factors. As this study focused on the effects of geometrical characteristics of dental implants, the authors tried to reduce the influence of biological and chemical factors as much as possible. For this reason a model of push-out test was set up. Cylindrical metal rods were imbedded in acrylic resin and were pushed out, meanwhile the force needed to disrupt the connection between the surface of the metal rods and the resin was measured and push-out strengths were calculated. Metal rods with three different lengths (7, 9, and 13 mm) and three different diameters (3.4, 4, 4.5 mm) were investigated. No correlation was found between implant length and maximum push-out strength. The mean push-out strengths were 17.32 MPa, 15.99 MPa and 15.56 MPa in groups, with 3.4, 4 and 4.5 mm diameter, thus the push-out strength decreases with increasing metal rod diameter. This may be attributed to the different distance between the outer circumference of the metal rods and the hole of the supporting table. Supporting this theory metal rods with identical diameter were examined, while the diameter of the hole on the supporting table was changed. The results demonstrated that larger holes on the supporting table resulted in higher push-out strengths. This indicates that comparisons of this variable should only be performed with standardized clearance of the hole on the supporting table. Push-out strengths of groups of cylindrical and conical implants with 9 degrees convergence were also investigated. The mean values were 16.57 MPa and 16.43 MPa, respectively. There was no statistically significant difference between the two groups. This means that results of experiments with all the above mentioned implant types are comparable, at least to that degree of conicity. As masticatory forces act usually on a surface, which is not perpendicular to the implant axis, we compared forces and push-out strengths that acted on surfaces with 10 degrees and 15 degrees inclination. The calculated average push-out strengths were 24.89 MPa and 22.56 MPa, respectively. More than twice as high push-out strengths were measured when threaded metal rods were compared to unthreaded ones (30.15 MPa, 14.89 MPa, respectively). Examining the effect of pitch of threads we compared the mean push-out strengths in three groups of threaded metal rods with pitch of threads 0.7, 1.0 and 1.25. The results were 28.86 MPa, 30.48 MPa, 31.12 MPa, respectively. The differences can be explained with the alteration in the dimension of the interface covered by the acrylic resin. Thus the effect of diameter, inclined opposing surface and threads must not be ignored if one compares the osseointegration capacity of different implants.

Angiotensin II type 1 (AT(1)) receptor blockade enhances the L-NAME-induced vasoconstriction in rat submandibular gland

The vasoregulatory role of nitric oxide (NO) and angiotensin II type 1 (AT(1)) receptors in the circulation of the submandibular gland (SMG) of rats was studied. The glandular blood flow was determined by means of laser Doppler flowmetry and rubidium isotope technique. The data obtained by these two methods correlated well (r = 0.77; P < 0.01). The AT(1) receptor antagonist candesartan (0.5 mg kg(-1), i.v.) reduced the vascular resistance in the SMG by 37 % (P < 0.05). By contrast, the NO synthase blocker L-NAME (15 mg kg(-1), i.v.) significantly increased vascular resistance in the SMG both in candesartan-treated (P < 0.001) and non-treated (P < 0.001) animals. The increase in resistance was greater (P < 0.05) after previous blockade of AT(1) receptors. These findings suggest that the AT(1) receptors have an important role in the vasoregulation of the SMG in the rat. As a result of AT(1) blockade, NO-dependent tone of glandular vessels may be enhanced significantly.

Influence of restorative manipulations on the blood perfusion of human marginal gingiva as measured by laser Doppler flowmetry

Plaque accumulation caused by deficient fixed prosthodontics may evoke unequal degrees of gingival inflammation. Clinical investigation was performed to study the reaction of marginal gingiva during the course of routine prosthetic rehabilitation, e.g. replacement of two two-unit fixed partial dentures for aesthetic and functional reasons in a female patient. To characterize the actual state of gingival margin we recorded conventional gingivitis indices in conjunction with the employment of non-invasive laser Doppler flowmetry (LDF) for gingival perfusion measurements. Prior to the treatment procedures (control phase) the gingival indices were scored to 1 at all the five measuring points. At the end of the rehabilitation those values decreased to zero. A significant correlation was found between gingival indices and LDF readings (r=0.37, n=49, P < 0.01). Thus, our data suggest that monitoring of gingival blood perfusion by LDF may provide valuable information on the healing process of inflamed marginal gingiva.

[Effectiveness of various procedures and instruments used in root canal treatment for reducing bacterial growth (in vitro comparison)]

In this study root canal preparation methods and instruments were compared by using forty extracted upper first bicuspids. The trepanated and extirpated teeth were sterilised in an autoclave, inoculated with Enterococcus faecalis and incubated for 24 hours at 37 degrees C. The teeth were divided into 5 groups as follows: those treated with K-file and K-file Nitiflex (step back technique, 1st, 2nd groups), with K-reamer (standard technique, 3rd group), those rinsed only with sterile saline solution (4th group), and those left untouched after incubation (5th group). Bacterial samples were taken before and after preparation and were inoculated onto special E67 plates. The plates were evaluated after 24 hours of incubation. It was concluded that the number of the bacteria could be significantly reduced with rinsing and mechanical preparation. There was no significant difference as to the efficacy of the preparation procedures or instruments applied.

Dose finding, placebo-controlled study of oral almotriptan in the acute treatment of migraine

OBJECTIVE

To assess the efficacy and tolerability of oral almotriptan, a selective serotonin receptor (5-HT1B/1D) agonist, when used at different doses in the treatment of acute migraine.

METHODS

This was a placebo controlled, double-blind, parallel-group, dose-finding study. Patients satisfying International Headache Society criteria for acute migraine were randomized to a single dose of placebo or oral almotriptan 2, 6.25, 12.5, or 25 mg at the onset of moderate or severe pain. Patients graded pain intensity on a 4-point verbal scale from 0 (no pain) to 3 (severe pain) and recorded adverse events. The primary efficacy variable was headache response at 2 hours. Data were analyzed on an intent-to-treat basis.

RESULTS

Nine hundred and three patients were randomized, and 742 were included in the evaluation of the efficacy and tolerability. Headache response at 2 hours was 32.5% with placebo, and 30%, 56.3%, 58.5%, and 66.5% with almotriptan 2, 6.25, 12.5, and 25 mg doses (p < 0.05 for 6.25, 12.5, and 25 mg vs placebo). A dose-dependent decrease in the incidence of migraine-associated symptoms and the need for escape medication was observed. The incidence of adverse events with the almotriptan 2-mg, 6.25-mg, and 12.5-mg groups was comparable to that with the placebo group.

CONCLUSION

Almotriptan 12.5 mg demonstrated the most favorable ratio between efficacy and tolerability, offering equivalent efficacy and better tolerability compared with the 25 mg dose. The minimum effective dose of almotriptan was 6.25 mg.

Neurogenic inflammation of gingivomucosal tissue in streptozotocin-diabetic rat

Previously it was assumed that nerve fibres are involved in the neurogenic inflammation induced by mechanical or chemical irriations. It has been also suggested that in diabetes mellitus the unmyelinated small diameter fibers are impaired as a result of diabetic neuropathy. Therefore, our aim was to study the alterations of the nerve processes in the gingivomucosal tissue in streptozotocin (STZ)-diabetic rats. Light- and electronmicroscopical examinations were made to analyze the changes in nerve fibres. After one week of steptozotocin treatment, the gingivomucosal tissue had inflammatory cell infiltration and some degenerated nerve fibres were also observed. Dense mitochondria, disorganization of cell organelles, and appearance of myelin-like dense bodies were found in the axons of degenerared nerve fibres. Semiquantitative analysis showed that 14 +/- 4% of the unmyelinated nerve fibres degenerated after one week of STZ treatment. However, degeneration of the myelinated nerve fibers was not observed. Two weeks after STZ treatment, most of the unmyelinated and myelinated nerve fibers showed degeneration (86 +/- 5%) and the placement of the ligature revealed a non-inflammatory connective tissue adjacent to a normal epithelium. The myelin sheath was disrupted and dark axoplasm with cytolysosomes became manifest. These findings demonstrated that both unmyelinated and myelinated nerve fibers are altered and inflammatory reaction exists in the gingivomucosal tissue only in the early stage of diabetes mellitus.

The effect of acid etching on vascular diameter of pulp-vessels in rat incisor (vitalmicroscopic study)

Conditioning agents used on dentin with composite materials are biologically active and may have deleterious effects on the pulpal microcirculation. No data are available on the immediate vascular effect of etching materials applied on a constant thin pulpal dentin. In this study the authors examined whether the application of 36% phosphoric acid (Conditioner 36, 15 seconds) or itakonic acid with 10% maleic acid (NRC Non-Rinse Conditioner, 20 seconds), as recommended by the manufacturers, alters the blood circulation in the pulp of the rat's lower incisors. The effect of prolonged etching time (60 seconds) was also assessed (Conditioner 36). The application of saline served as the untreated control. The technique of vitalmicroscopy was used on the first lower incisor of 40 (10-10 in each group) male Sprague-Dawley rats (weighing 350 +/- 8 g SE) to record the changes in vessel diameter prior to and at 5, 15, 30 and 60 minutes after the test materials were administered on the dentin. In the control rats, the vessel diameter was stable during the entire experiment. Acid conditioning as recommended by the manufacturers tended to cause vasodilatation, though these alterations were statistically not significant when compared to the control group (ANOVA, p > 0.05). After prolonged etching time (Conditioner 36, 60 seconds) significant vasoconstriction (-14.4 +/- 6.13; -10.59 +/- 4.2; -11.96 +/- 6.75; -5.49 +/- 5.78%) was observed (ANOVA, p < 0.05). In this group, stasis developed in pulpal blood circulation in 40% of rats (Cochran's-Q test, p < 0.05), gas-bubble formation was observed in 30% and the disappearance of the pulpal wall occurred in 20%. These results suggest that exposition time with acid is crucial to the pulpal microcirculation. That is, acid conditioning applied as indicated (for 15-20 seconds) onto a very thin layer of dentin only slightly affects the blood supply to the dental pulp; however, prolonged etching time (for 60 seconds) results in immediate failure of microcirculation in the dental pulp of rats.

Systemic fat and thrombus embolization in patients undergoing total knee arthroplasty with regional heparinization

A double-blind, randomized, controlled study was undertaken to determine if a technique of intraoperative anticoagulation would decrease the incidence or severity of venous embolization after tourniquet release during total knee arthroplasty. Sixty-six patients were randomized to receive either the heparin or placebo treatment. Transesophageal echocardiography was performed before and after tourniquet release to detect embolic material in the right atrium. Transient opacification of the right atrium was observed in all patients within the first 30 seconds after tourniquet release. Regional limb heparinization is not effective in reducing the intensity of right atrium opacification because much of the echogenic material was composed of fat rather than thrombus.

Role of nitric oxide in the regulation of blood flow in the rat submandibular gland during carotid artery occlusion

The possible involvement of nitric oxide in the preservation of blood flow to the rat submandibular gland after uni- or bilateral occlusion of the common carotid was studied. Glandular blood flow and mean blood pressure were monitored before, during and after carotid occlusion in the presence and absence of the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine-methyl-ester (L-NAME). To calculate vascular resistance, the local perfusion pressure distal to the point of occlusion was also measured. In normal rats, uni- or bilateral carotid occlusion resulted in an immediate decrease in ipsilateral glandular blood flow. After the cessation of carotid occlusion, hyperaemia was observed in the submandibular gland. Both local perfusion pressure and vascular resistance decreased during carotid occlusion. In the group pretreated with L-NAME, trends in blood-flow responses to uni- or bilateral occlusion were identical to those registered in the control groups, though the magnitude of the alterations was significantly less. The well-maintained glandular blood flow was due to functioning vascular anastomoses and compensating dilatation of glandular blood vessels. Nitric oxide had only a restrained effect on this compensatory mechanism.

[Reproducibility of the laser fluorescence method for the diagnosis of occlusal caries. Clinical study]

The aim of the study was to assess the reproducibility of recently developed laser fluorescence method for occlusal caries detection in vivo. 71 non-cavitated premolar and molar teeth were examined repeatedly by three dentists using DIAGNOdent (KaVo) instrument. The presence of caries has been established on the classification of Lussi, created on the basis of "in vitro" investigations. The reproducibility of the measurements were expressed in rank correlation of Spearman. The intra- and interexaminer reliability was also determined by Kappa statistics. The Spearman correlation coefficiencies were fairly high (0.738-0.949) The intraobserver and interobserver coincidencies reflected by Kappa values (0.60-0.88 and 0.44-0.77, respectively) were also convincing.

Prognostic histological and immune markers of renal cell carcinoma

Recent development on the fields of molecular genetics and immunology of human renal cell carcinoma (RCC) have resulted in more successful treatment of advanced and metastatic RCCs. Re-evaluation of the prognostic/predictive data aim the initial tumor staging of RCC patients to achieve better patient selection for immune and gene therapy. 125 RCC patients diagnosed according to the Heidelberg histological classification, graded, Robson staged, immune treated (Interferon-a a+ Vinblastine or Broncho-Waxom/Decaris) were followed-up clinically for 36 months. Tumor immunity markers by immunohistochemistry of tumor infiltrating lymphocytes (TIL) were detected by immunoperoxidase methods using monoclonal antibodies. Tumoral immune complexes (TIC) were visualized by fluorescent polyclonal antibodies. Histologically oncocytomas defined a better (p<0.02) and sarcomatous RCCs a worse (p<0.01) follow-up prognosis. Basically, the metastatic status (related with the stage and grade) determined the clinical outcome (p<0.00002) of the RCC patients. Tumoral immune complexes (TIC) were weak positive, while tumor infiltrating lymphocytes (TIL) weak negative predictors of the succes of Broncho-Waxom/Decaris immune therapy. Molecular genetic based histological classification, grade, stage and metastatic status parameters together with some tumor immunity parameters (TIL, TIC) can predict the success of immunotherapy of RCC patients.

[Adsorption of human serum proteins to titanium dioxide]

In order to find an in vitro biochemical model for investigation of osseointegration in terms of dental implantology, the aim of the present study was to analyse the adsorption of human serum proteins to titanium dioxide. Titanium dioxide powder was suspended in human serum. After incubation and centrifugation the TiO2 with the adsorbed proteins were washed with distilled water, ethylendiaminetetraacetic acid (EDTA) supplemented with ammonium hydrogencarbonate (NH4HCO3) solution, and sodium dodecylsulphate (SDS), after centrifugation the supernatant fluid was collected and SDS polyacrylamide gel and native (Biomidi) gel electrophoresis were conducted to determine the type of the adsorbed proteins. Our results show, that albumin was adsorbed to TiO2, but it could be easily removed. The adsorption of a 94 kDa protein was much stronger than the other proteins. The method seems to be useful in the investigation of the protein adsorbing ability of differently treated titanium implant surfaces.

[Effect of retraction materials on the blood supply of marginal gingiva]

Effect of knitted cord and retraction medicaments applied to achieve gingival displacement prior to taking impression has been studied on the blood supply of marginal gingiva of volunteers using laser Doppler flowmetry. Immediately after application of #00 cord saturated with 0.9% saline, 25% AlCl3 or 15.5% Fe2(SO4)3 solutions, significant decrease of blood perfusion was registered. Removal of cords containing medicaments resulted in prompt gingival hyperemia. However, vasoconstriction observed as a consequence of cord application saturated with 0.1% epinephrine proved to be long-lasting and persisted even in the 20th min of cord removal. In conclusion our results suggest that the reduced perfusion of marginal gingiva is evoked by the mechanical compression of retraction cord. At the time of making impression, which procedure in clinical practice is due immediately after cord removal, the blood flow of marginal gingiva is elevated. Permanent hypoperfusion can be achieved only by the means of cord impregnated with 0.1% epinephrine.

[Effect of water storage and intrapulpal pressure on microleakage of three restorative materials]

Three different restorative materials, Z100 composite, F2000 compomer and Vitremer glass ionomer cement are currently proposed for Class V restorations. The aim of this in vitro study was to evaluate the influence of water storage and the simulated intrapulpal pressure (sIP) on the quality of the margins of class V restorations located both in enamel and dentin. The water resorption of restorative materials containing hydrophilic groups (compomers and glass ionomer cements) can favourably modify the marginal sealing ability by hydroscopic expansion. The influence of the sIP was specific to the material. While F2000 compomer and Vitremer glass ionomer cement were un-influenced by sIP, with Z100 composite a significant difference could be observed. It was concluded that F2000 compomer and Vitremer glass ionomer cement showed significantly less microleakage, which means a better marginal sealing ability than Z100 composite.

Blood flow of the right and left submandibular gland during unilateral carotid artery occlusion in rat: role of nitric oxide

The aim of the present study was to investigate the effect of unilateral carotid artery occlusion on the blood flow of submandibular gland in anesthetized rats and identify the role of nitric oxide (NO) in blood flow changes after the artery occlusion. L-NAME (N omega-nitro-L-arginine-methyl-ester; 10 mg/kg/day, per os) dissolved in tap water was used to block nitric oxide synthase. Glandular blood flow was measured using Sapirstein's indicator (86Rb) distribution technique. In the control animals the blood flow of left (ligated side) submandibular gland was lower than in the right (unligated side) one (right: 76.4+/-15.4 ml/min/100 g, 64.1+/-13.4 ml/min/100 g, p<0.01). The blood flow of submandibular glands decreased in NOS blocked group versus control. The vascular resistance after L-NAME treatment was elevated (control: 11+/-2.3 R/kg, L-NAME: 17.5+/-4.1 R/kg, p<0.001). In L-NAME group the difference between blood flow value of the left and right submandibular gland was significantly lower than in the control group (control: -16%, NAME: -8%, p<0.01).

CONCLUSION

The maintenance of the blood flow in the left submandibular gland during ligation of the left common carotid artery could be due to the good vascular anastomotic system at these regions and adaptation of the submandibular vessels to the decreased perfusion pressure. Nitric oxide may have a role in the regulation of blood flow tinder this condition.

Implant-prosthetic rehabilitation after segmental mandibulectomy and bone grafting

A free vascularized fibula (6 cases) and iliac bone (11 cases) graft were used to reconstruct a mandibular discontinuity defect resulting from cancer surgery in 17 patients. Fifty-two osseointegrated DenTi implants were secondarily placed into the grafted bone, and all the patients underwent prosthetic rehabilitation. (DenTi is an endosseous dental implant system invented and manufactured by Denti-System Ltd., Szentes, Hungary.) To date, the maximum follow-up time after prosthetic treatment is 5 years, the minimum is 2 years. During this time, only one of the 52 inserted implants was lost, and that occurred a few days after insertion. Clinical signs of peri-implantitis were observed in only 2 of the fixed prosthetic restorations. Long-term maintenance is essential if such patients are to achieve successful prosthetic restorations and, thus, enhanced lives.

A ten-year clinical follow-up study of prosthetic rehabilitation of the edentulous lower jaw with endosteal dental implants

This paper reports on 10 years of clinical experience with implant prosthodontic treatment of total edentulism. During this period, of the 735 implants that were inserted, only 19 were lost, a 97.4% success rate. The authors believe that evaluating the success of implant treatment requires examining the health of the peripilastrium with periodontologic methods. The indices the authors used for such an evaluation were plaque accumulation, crevicular fluid flow rate, and sulcus bleeding; crevicular fluid flow proved the most satisfactory for estimating the health of peri-implant tissues. The results demonstrate that peri-implant-tissue health is similar to that of the tissues surrounding nontreated natural teeth and better than that of the tissues surrounding natural teeth wearing crowns.

[Blood flow in marginal gingiva as measured with laser Doppler flowmetry]

The clinical application of laser Doppler flowmetry (LDF) provides data on the blood flow of marginal gingiva (GBF) at different dental regions. The aim of the present investigation was to study the GBF at different teeth. Ten adult subjects with good oral hygiene were involved in this experiment. In a series of experiments GBF was recorded bilaterally positioned the flow probe on three sites 1 mm above the marginal gingiva of the upper and lower central incisors. In another series of investigations the same technique was used for GBF registrations at six permanent teeth on the right side (11-16; according to FDI notation). The mean blood flow values obtained at 3 different places of marginal gingiva of the front teeth were nearly identical, therefore the data were pooled. The GBF values registered at the six upper right teeth also showed close similarity (p > 0.30). No differences were observed between the mean GBF values at the left and right central incisors (p > 0.80). There was a significant gingival blood flow value elevation at lower incisors as compared to that in the upper jaw (p < 0.05). Our results indicate that there is homogeneous marginal blood perfusion both in the maxillary and mandibula healthy gingiva. However, difference exists in blood supply between the upper and lower jaws in favor of mandibular marginal gingiva.