Spectrophotometric analysis of all-ceramic materials and their interaction with luting agents and different backgrounds.

In this study, two All-Ceramic (AC) materials--Empress 2 (EMP) (Ivoclar Vivadent AG, Schaan, Liechtenstein) and In-Ceram ALUMINA (ICA) (Vita Zahnfabrik, Bad Säckingen, Germany)--were analyzed, along with the effects of 3 luting agents-viz. Zinc Phosphate cement (ZNPO, PhospaCEM PL, Ivoclar Vivadent AG, Schaan, Liechtenstein), Glass Ionomer Cement (GIC, Ketac-Cem Radiopaque, ESPE Dental AG, Seefeld, Germany), and Compolute (COMP, ESPE Dental AG, Seefeld, Germany)--on the final color, using the CIELab system. Color differences (DeltaL, Deltaa, Deltab, and DeltaE) were calculated for samples with luting agents and for samples without luting agents with standard white and black backgrounds, with the use of a spectrophotometer, Luci 100 (Dr. Lange, Berlin, Germany). One-way ANOVA for DeltaL, Deltaa, Deltab, and DeltaE within both the AC systems, with and without luting agents, showed significant contributions of the background (p < 0.05). EMP was seen to be more translucent than ICA. Darker ceramics showed less color variation. Luting agents altered the final color of the restoration. ZNPO was least translucent, followed by GIC and COMP. Marginal increases in thicknesses of ICA samples (0.4 mm) do not show a statistically significant color difference. No method exists to predict the outcome of an AC restoration based on consideration of the luting agent and the background color.

Significance of saliva for the denture-wearing population.

UNLABELLED: This paper summarises a series of studies already published in German and presents new data related to the aetiology of the 'dry mouth' and its associated problems. AIMS: To study factors affecting mucous and serous salivary gland secretion, the aetiology of the 'dry mouth' and its associated problems, causative factors for hyposalivation and it's treatment. SETTING: Two university dental hospitals. SUBJECTS: 587 denture wearers and 521 control subjects, and autopsy material. INTERVENTIONS: Exercise, chewing, water, oestrogen, pilocarpine, and anetholtrithion therapy, biopsy of the minor glands. MAIN OUTCOME MEASURES: Palatal secretion (PAL, microL/cm2/min) and parotid salivary flow (PAR), subjective complaints and clinical findings. RESULTS: Resting flow rates for PAL between 0 and 65 microliters/cm2/min were seen in every age group. The flow rates of PAR (0 to 3.7 ml/10 min) were not correlated with PAL. Most patients with a resting flow rate of PAL < or = 6.0 microliters/cm2 suffer from a 'dry mouth' and Burning Mouth Syndrome (BMS) or oral dysaesthesia (OD) with or without chronic lesions of the oral mucosa. Etiological factors for the incidence of reduced PAL and associated problems include xerostomic drugs, oestrogen deficiency, radiotherapy, thyroid dysfunction, smoking or continuous wearing of complete upper dentures. PAL also correlated with the retention of upper complete dentures. PAL was correlated with the water content of epithelial tissues. PAL and PAR were both increased by drinking ample fluid, improving their circulation by physical exercises, chewing intensively, or taking oestrogens, pilocarpine, anetholtrithion. CONCLUSIONS: Variation in palatal salivary secretion occurs and is clinically important.

The effect of splinting of teeth in combination with reconstructive periodontal surgery in humans.

The purpose of this study was to evaluate the effect of splinting teeth on the results of periodontal reconstructive surgery using a specific carbonate bone replacement graft (BRG) material. Forty-five patients were randomly treated with a periodontal surgery approach. Natural coral calcium BRG was utilised in 33 patients. This 33-patient group was divided into three equal groups. In the presplint group, teeth were splinted to at least two rigid teeth before surgery, in the postsplint group, teeth were splinted at suture removal, and in the nonsplint group, the treated teeth were not splinted at all. In 12 patients, teeth were treated with surgical debridement (DEBR) alone and not splinted. Periodontal probing depth (PPD), clinical probing attachment level (CPAL), and tooth mobility were measured using desmodontometry (DDM) and periotest (PTV) with reproducible methods before surgery and at various periods up to 1 year afterwards. A decrease in PPD (5.4 mm, SD 1.4 mm) and tooth mobility (DDM-horizontal 257 microns, SD 60 microns) and a gain of CPAL (5.1 mm, SD 1.4 mm) were seen following the use of BRG in presplint teeth. In the same group, PPD and tooth mobility were significantly reduced compared to nonsplint teeth. DEBR alone showed reductions in tooth mobility and PPD and a significantly smaller gain in CPAL than in presplint teeth treated with BRG. The less favourable improvement in periodontal function of postsplint or nonsplint teeth seemed to be due to the loss of BRG material caused by tooth mobility. These results indicate that an undisturbed wound healing process using BRG together with tooth stability is beneficial to overall clinical success.

[Nosocomial pneumonias in a neurology intensive care unit]. / Nosokomiale Pneumonien auf einer neurologischen Intensivstation.

BACKGROUND AND OBJECTIVE: Nosocomial pneumonia in patients in an intensive care unit (ICU) are a great problem as a cause of increased morbidity and mortality as well as the resulting high cost of treatment. This study was aimed at determining the incidence of nosocomial pneumonia and the risk factors for its occurrence in patients with severe neurological disease. PATIENTS AND METHODS: Between 1.1. and 31.12.1997, 217 patients (125 men, 92 women; average age 63.4 years) were prospectively included if they were treated for more than 48 hours in the ICU of the Neurology Department of Erlangen University. The occurrence of nosocomial pneumonia (NP) was noted, using the criteria of the Center of Disease Control and Prevention (CDC). Incidence of the diseases was related to age, sex, initial state of consciousness, type of ventilation, duration of stay in the ICU and any associated medical condition. RESULTS: NP was diagnosed in 68 patients (31.4%). Statistically significant relative risks were male sex (2.4 fold, P < 0.01), clouded consciousness with a Glasgow coma score < 8 (6.2 fold, P < 0.001), mechanical ventilation (8.4 fold, P < 0.001), time in ICU > or = 8 days (9.3 fold, P < 0.001) and associated medical condition (3.3 fold, P < 0.005). In 17.7% of cases no relevant pathogen was identified microbiologically. A mixed infection was present in 36.8% of cases. The most common Gram-positive organism was Staph, aureus (35.3%), the most common Gram-negative ones were Ps. aeruginosa (25%), Kl. pneumoniae and Kl. oxytoca (11.8%), E. Coli (10.3%) and Acinetobacter species (7.4%). There was also a high rate of infection or infestation with Candida albicans or glabrata (41.2%). NP played a clinically decisive role in the fatal course of 13 of the 47 patients who died. CONCLUSION: These data (incidence, relative risk) can, by taking into consideration various aspects of specialist and hospital hygienic practices, contribute to a continuing optimization of the prevention and treatment of disease.

[Detection of patent foramen ovale. Transesophageal echocardiography and transcranial Doppler sonography with ultrasound contrast media are "supplementary, not competing, diagnostic methods"]. / Detektion eines offenen Foramen ovale. Transösophageale Echokardiographie und transkranielle Dopplersonographie mit Ultraschallkontrastmittel sind "ergänzende, nicht konkurrierende Methoden".

BACKGROUND: The prevalence of patent foramen ovale (PFO) in healthy individuals is estimated to be about 25% and is elevated to 40% patients with stroke. To date transesophageal echocardiography (TEE) was considered to be the most sensitive method to detect PFO and was regarded as the gold standard. Transcranial Doppler sonography of the middle cerebral artery during contrast injection (c-TCD) has recently been proposed as an alternative method for the detection of PFO. We report our experience on 45 patients (age < 55 years) with stroke or transient ischemic attack (TIA) in whom both c-TCD and TEE were performed to detect PFO as a mechanism for embolic cerebral ischemia. PATIENTS AND METHODS: In 45 patients (21 women, 24 men, mean age 41.4 years ranging from 17 to 54 years) with cerebral ischemia, both standardized TEE and standardized c-TCD were performed separately. When any PFO was found by TEE and/or c-TCD, it was classified as positive. If c-TCD was positive but TEE negative, a second TEE was performed and vice versa. RESULTS: PFO was found epicritically in 26 patients (57.8%). First TEE detected PFO in 24 cases (sensitivity 92.3%). Separately performed c-TCD detected PFO in 22 cases of the PFO-positive cases (sensitivity 84.6%). However, c-TCD detected PFO in 2 cases, in which the first TEE had been negative, leading to a second TEE which confirmed PFO and demonstrated minimal shunt (7.7%). TEE detected PFO in 4 cases in which first c-TCD was negative. A second c-TCD confirmed in 2 of these 4 cases a positive right-to-left shunt. Neither method revealed false positive results (specifity 100%). The positive predictive value was 100% in both methods. The negative predictive value in TEE was 90.5% and in c-TCD was 82.6%. CONCLUSION: TEE and c-TCD are not concurrent diagnostic tools to detect PFO. Both supplement each other. If both methods are used in all PFO-suspected patients, PFO detection rate is higher than when using either method alone.

Radiation-induced hyposalivation and its treatment with oral pilocarpine.

OBJECTIVE: The aim of this study was to determine the effects of radiation on the secretion of saliva from mucous salivary glands in comparison with serous salivary glands. STUDY DESIGN: The minor salivary glands of the palate were used as an example of mucous glands, while the parotid glands were used as an example of a serous secretion organ. Serial flow rate measurements of the parotid and palatal glands were taken over a period of approximately 9 months in 13 patients who suffered from malignancies of the head and neck region. Twelve patients consented to take part in a second study in which salivary flow was stimulated by oral pilocarpine before and at the conclusion of radiotherapy and 7 months later. Complaints and symptoms were recorded at each time of measurement. RESULTS: After radiotherapy, the secretory performance of the parotid glands dropped off rapidly and irreversibly. Salivary secretion from the palatal glands was not totally diminished as a result of radiation. Clinical complaints and histologic findings indicate a serious alteration of the tissues irradiated; however, residual secretion from the remaining parenchyma of the mucous glands still remains. Pilocarpine produced a clinically significant increase of salivary flow from the palatal glands before and 7 months after radiation. Secretory performance of the parotid glands could not be sufficiently increased by stimulation with pilocarpine after radiotherapy. Clinical side effects and risks for the treatment of symptomatic postradiation xerostomia with pilocarpine were minimal. CONCLUSIONS: These findings emphasize the greater resistance and recoverability of the mucous secreting minor palatal glands in comparison with the serous secreting parotid glands. They also indicate the significant postradiation ability of the mucous secreting glands to be stimulated by pilocarpine.

Reactions of peri-implant tissues to continuous loading of osseointegrated implants.

Functional and morphologic reactions of peri-implant bone surrounding screw implants (Bonefit) were studied in three dogs by loading the implants with continuous forces of 2 (about 204 gm) and 5 N (about 510 gm). Eight implants were inserted to an endosseous length of 12 mm and placed about 10 mm apart in the region of the lower premolars. The fixtures healed in a closed environment for 12 weeks, after which they were uncovered and loaded with abutments and orthodontic devices to produce horizontal distraction with a force of 2 N (about 204 gm) for 12 weeks. Subsequently they were loaded with 5 N (about 510 gm) for another 24 weeks. The distance between and the mobility of the implants were determined before and after each phase of experimental loading. Fixtures of the same type that were osseointegrated and not exposed, or osseointegrated and loaded by mastication, were used as a control. Animals were euthanized and specimens sectioned. The result was that continuously loaded implants showed no significant displacement for any force level. The mobility of the fixtures increased slightly by about 1 Periotest-value (PTV) at the end of the experiment. No significant peri-implant pocket could be seen in implants loaded by continuous or masticatory forces. Histologic and morphometric evaluation indicated compaction of bone as a result of loading. Osseointegrated implants have potential as a firm osseous anchorage for orthodontic treatment and can resist continuous horizontal forces of at least 5 N (about 510 gm) during a period of several months.

DC electrical field-induced c-fos expression and growth stimulation in multicellular prostate cancer spheroids.

The effects of electrical direct current (DC) field pulses on c-fos expression, growth kinetics and vitality patterns of multicellular tumour spheroids (MCSs) were studied. Monitoring the membrane potential of MCSs by di-8-ANNEPS staining and confocal microscopy during DC electrical field treatment revealed a hyperpolarization at the anode-facing side and a depolarization at the cathode-facing side. When a single 500 V m(-1) electrical field pulse with a duration of 60 s was applied to MCSs (150-350 microm in diameter) an enhancement of the growth kinetics within a period of 6 days post pulse was observed. Whereas the volume doubling time amounted to 4-5 days in control samples, it was reduced to 1-2 days in electropulsed MCSs. At day 6 post pulse the diameter of the necrotic core was significantly smaller than the control. The critical diameter for the first appearance of central necrosis amounted to 350 +/- 50 microm in the control and 450 +/- 50 microm in the electropulsed MCSs. Coincidentally, the proliferating rim was increased to 107 +/- 11 microm in electropulsed MCSs as compared with 60 +/- 6 microm in the control. The growth stimulation may be mediated by the proto-oncogene c-fos as its expression increased by a factor of 2.5 within 2 h post pulse. c-fos expression declined towards control values within 8 h post pulse.

The paradox between resistance to hypoxia and liability to hypoxic damage in hyperglycemic peripheral nerves. Evidence for glycolysis involvement.

Isolated ventral and dorsal rat spinal roots incubated in normal (2.5 mM) or high glucose (25 mM) concentrations or in high concentrations of other hexoses were exposed transiently to hypoxia (30 min) in a solution of low buffering power. Compound nerve action potentials, extracellular direct current potentials, and interstitial pH were continuously recorded before, during, and after hypoxia. Ventral roots incubated in 25 mM D-glucose showed resistance to hypoxia. Dorsal roots, on the other hand, revealed electrophysiological damage by hyperglycemic hypoxia as indicated by a lack of posthypoxic recovery. In both types of spinal roots, interstitial acidification was most pronounced during hyperglycemic hypoxia. The changes in the sensitivity to hypoxia induced by high concentrations of D-glucose were imitated by high concentrations of D-mannose. In contrast, D-galactose, L-glucose, D-fructose, and L-fucose did not have such effects. Resistance to hypoxia, hypoxia-generated interstitial acidification, and hypoxia-induced electrophysiological damage were absent after pharmacological inhibition of nerve glycolysis with iodoacetate. These observations indicate 1) that enhanced anaerobic glycolysis produces resistance to hypoxia in hyperglycemic peripheral nerves and 2) that acidification may impair the function of peripheral axons when anaerobic glycolysis proceeds in a tissue with reduced buffering power.

Parameters of tooth mobility in cases of normal function and functional disorders of the masticatory system.

Tooth mobility was measured mechano-electronically with the aid of quasi-static and dynamic methods in 309 patients comprising 2650 teeth being periodontally healthy. Besides, clinical and roentgenographic findings were ascertained to relate functional features to each periodontium. In general the result was that teeth loaded excessively show increased mobility parameters compared to those loaded normally. However, the mobility of teeth loaded poorly or deficiently was even greater compared to teeth stressed excessively. Moreover, follow-up studies showed that tooth mobility decreases after removal of functional disorders of the masticatory system or an immobilisation of splinted teeth. An experimental trauma of the periodontal ligament also brings on an increased tooth mobility which decreases to the original values some days after the trial.

Salivary secretion and denture retention.

Correlations between the retention of complete dentures and flow rates of the palatal and parotid glands were studied in 86 patients. The determination of secretion rates and forces of the forward leverage leading to a dislocation of the dentures showed a narrow correlation between the secretion of palatal glands and the retention of maxillary dentures. The retention of mandibular complete dentures is adversely influenced by the secretion rate of minor salivary glands. However, there is no correlation between the flow rate of parotid saliva and the retention of either denture. In addition, the medicinal stimulation of salivation showed that an increase of mucus secretion induced an improved retention of maxillary complete dentures.

[Factors involved in endosseous implant function]. / Faktorenerfassung zur Funktion enossaler Implantate.

Periodontometric and Periotest mobility parameters of 87 endosseous implants were studied during a period of up to 6 years. Moreover, the condition of the surrounding bone and mucosa was assessed by means of the Periodontal Index (PI). Mobility of endosseous implants was lowest during the first year of insertion and highest at the end of the study. Among all those variables that had a favorable effect on implant function, the length of the implants was in the first line. What is called the osseointegration of dental implants is no longer evident after just a short period of masticatory loading by a denture. Mobility parameters of implants then increase to those of periodontally healthy natural teeth. Improved dental hygiene and cleansing of the periimplant area reduce the incidence of pathological findings and improve the prognosis of dental implants.

[Pathohistological findings in palatine glands in autopsy and biopsy material]. / Pathohistologische Untersuchungsbefunde der Glandulae palatinae an autoptischem und bioptischem Material.

Histological examinations of the palatine glands were performed in 100 postmortem cases and 65 biopsies of outpatients. These data were related to personal characteristics, such as age, sex, denture-wearing and certain primary diseases. The histological results of the postmortem material were found to be only partly comparable to those of the biopsy specimens. The pathohistological findings in the parenchyma of the outpatients proved to be less pronounced in the individual groups than those of the postmortem cases. An evaluation of the postmortem findings showed inflammatory, ectatic and metaplastic alterations of the ducts as well as atrophies and inflammations of the parenchyma, particularly in baseplate denture wearers and with increasing age. In persons under 65 the tissue irritation caused by baseplate dentures resulted in increased gland and duct alterations. In the dead above 65 the difference between age-dependent and denture-induced alterations of the parenchyma was statistically immaterial.

[Ultrastructural studies on obstructive palatal sialadenitis in denture wearers]. / Ultrastrukturelle Untersuchungen zum Stauungsphänomen der palatinalen Speicheldrüsen bei Prothesenträgern.

The ultrastructural phenomena of obstructive palatal sialadenitis were studied in 7 denture wearers versus 3 non-denture wearers as control. Apart from mucositis severe stagnation of salivary flow in the excretory ducts was observed in patients with dentures with short periods of service. In contrast to the control group there were mucous droplets after exocytosis of the acinus cells that remained intact even in the lumina of the distal excretory ducts. Desquamation of the duct and acinus cells results in a change in the organic components of the secretory mucus. The periductal infiltrate consisted mainly of plasma cells and lymphocytes, whereas neutrophils or macrophages were not observed. Ultrastructurally there was no evidence of an ascending microbial infection of the ducts. Probably, infections do not play an important role in the pathogenesis of obstructive palatal sialadenitis.

[Physiology and pathophysiology of the minor salivary glands]. / Physiologie und Pathophysiologie der kleinen Speicheldrüsen.

Measurements of the secretory rates of the palatine and the parotid glands, assessing the electrolyte content of all salivary fractions and combined clinical biotic studies underline the clinical importance of the minor salivary glands. The minor salivary glands are shown to be organs whose function is decisively involved in symptoms such as xerostomia, stomatodynia, and what is known as "denture intolerance". Moreover, proper secretion of the palatine glands is of crucial importance for the physical retention of maxillary full dentures. There are no connections between secretory rates of major and minor salivary glands. The effect of certain drugs on salivary production and thus on the symptoms of hyposalivation seems to be considerable. Treatment methods for inadequate salivary secretion are outlined. The adaptive tendency of properly functioning palatine glands appears to be high. The fact that atrophic and dystrophic processes can be functionally compensated to a relatively high degree speaks for the dynamic capability of the glandular parenchyma. In view of the clinical relevance of the minor salivary glands it is mandatory that the functional principles and control mechanisms underlying their secretion be investigated in future studies.

[Biometric studies on implanted and natural abutments]. / Biometrische Untersuchungen an implantierten und natürlichen Prothesenpfeilern.

The mobility of 50 osseointegrated implants, inserted for improvement of the support of dentures in edentulous lower jaws, was studied during a period of up to 3 years by means of mechano-electronic measurements. The results showed that 3 months after implantation osseointegrated implants have less quasi-static mobility than natural teeth without periodontal lesions. Under the stresses of mastication the mobility of osseointegrated implants continuously increases. After 2-3 years, implants show a similar mobility as natural teeth supporting comparable denture constructions. The Periotest readings of implants were significantly lower than those of natural teeth, largely independent of the date of mobility measurement. A prognosis of functional properties as well as predicting the impending loss of osseointegrated implants is possible with the aid of long-term mobility measurements.

[Reactions of the oral mucosa to mechanical load stimuli from dentures]. / Reaktionen der Mundschleimhaut auf Belastungsreize der Prothese.

The oral mucosa is the primary medium bearing removable dentures. Problems of adaptation and incompatibility of denture bases borne by mucosal tissues first of all arise at the mucosa covering the palate and the alveolar ridges. Depending on its functional qualities, the denture bearing mucosa more or less fulfills the task of buffering chewing forces acting on the denture base and distributing them on the bone surface. Studies on physiological and morphological reactions of the denture bearing tissues resulting from mechanical stresses show that the mucosa is entirely capable of tolerating short-term pressures during chewing. In this connection the increase in the thickness of the denture bearing mucosa must be considered as a physiological response to mechanical load.

[Morphological and functional characteristics of the palatal mucosa and the palatine glands]. / Morphologische und funktionelle Merkmale der Gaumenschleimhaut und der G11. palatinae.

Histologic findings of the palatal mucosa and the palatal glands of 73 patients with and without upper dentures were compared with distinctive marks, complaints and clinical diagnoses as well as with the secretion of the minor salivary glands. Patients complaining of oral burns show the same rate of patho-histologic findings as those without any complaints. Inflammation and atrophic reactions of the palatal mucosa and the palatal glands do not reduce the secretion rate of the minor glands. In these cases, however, considerable changes of the quotient exist between sodium and potassium ions of the palatal saliva secretion. Signs of inflammation of the palatal tissues were seen more frequently in full denture wearers and especially in those wearing upper dentures during day and night. Causative factors of denture incompatibility are discussed.

[Studies on the mechano-electronic measurement of tooth mobility]. / Vergleichende biometrische Untersuchungen zur mechano-elektronischen Bestimmung der Zahnbeweglichkeit.

The correlations between dynamic and quasi-static mechano-electronic measurements of tooth mobility were investigated in more than 1500 teeth. The two methods correlate quite well with the conventional classification (in Germany). On the other hand, there is no correlation between dynamic and quasistatic mechano-electronic measurements. Nevertheless distinctive signs and periodontal findings could be verified by mechano-electronic evaluation of tooth mobility.