Shrinkage stresses associated with incremental composite filling techniques in conservative Class II restorations.

Conservative Class II preparations are widely utilized, however the stresses produced by incremental composite placement/curing has not been demonstrated. The purpose of this investigation was to visualize the stresses generated by composite resin placed into photoelastic models of conservative Class II preparations using different incremental techniques. Conservative Class II preparations on three different primary molar replicas were cast life-sized in a photoelastic material. Incremental placement/curing techniques used were oblique, gingival-occlusal, and facial-lingual and were compared with bulk placement/curing. The photoelastic stresses produced with conservative Class II restorations were of lower intensity than conventional Class II and larger composite restorations previously reported. Few differences in shrinkage-induced stresses were observed between the incremental placement/curing techniques tested. Lowest shrinkage stresses were generated by the bulk placement/curing technique.

Shrinkage stresses associated with incremental composite filling techniques.

It is commonly accepted that stresses associated with polymerization shrinkage of composite restoratives can be reduced by utilization of an incremental filling procedure. A recent report using finite element analysis on a simple box preparation has shown that such a procedure actually produces higher stresses. The purpose of this investigation was to visualize the stresses generated by composite resin placed into photoelastic models of two surface preparations using different incremental techniques. Primary molar preparations were cast life-sized in a photoelastic material. Cavity walls were cleansed, primed and coated with unfilled resin. Incremental filling techniques of a hybrid composite resin were gingivo-occlusal, oblique, and facio-lingual. Comparisons were made with the bulk placement technique. The stresses developed within the model teeth were observed in the field of a circular polariscope under magnification. Generally few differences in shrinkage-induced stresses, were observed between the incremental filling techniques tested. The lowest shrinkage stresses were generated by the bulk placement technique.

[Antineoplastic effectiveness and unwanted side effects of polychemotherapy of extensive oro- and hypopharyngeal cancers--results of a prospective therapy study with 5-FU/cisplatin versus 5-FU/carboplatin]. / Antineoplastische Wirksamkeit und unerwünschte Nebenwirkungen der Polychemotherapie ausgedehnter Oro- und Hypopharynxkarzinome--Ergebnisse einer prospektiven Therapiestudie mit 5-FU/Cisplatin versus 5-FU/Carboplatin.

60 patients with advanced carcinomas of the oropharynx and hypopharynx underwent chemotherapy, either with 5-FU/Cisplatin (n = 30) or with 5-FU/Carboplatin (n = 30). The remission-rates (complete and partial remissions) were comparable in both groups. The rate of complete remissions, however, was statistically significant higher in the cisplatinum group (6 patients) than in the carboplatinum group (1 patient). 2 patients of the 5-FU/Cis-group and 4 patients of the 5-FU/Carbo-group developed a progressive disease during chemotherapy. Statistically significant differences were found in the nephrotoxic and myelotoxic side effects between both therapy groups: nephrotoxic side effects were more frequent in the 5-FU/Cis-group, whereas myelotoxic side effects occurred mainly in the 5-FU/Carbo-group. The chemotherapy with 5-FU/Carboplatin was better tolerated by the patients than in the 5-FU/Cisplatinum-group. In the 5-FU/Carbo-group especially a lower rate and severity of loss in weight, nausea, vomiting, alopecia and mucositis/stomatitis was observed. No statistically significant differences were found in ototoxic side effects between both groups.

[A new implant system in head and neck surgery]. / Ein neues Implantatsystem in der Kopf-Hals-Chirurgie.

Defects in the head and neck region following extensive tumor removal are sometimes difficult to reconstruct by local or free flaps. An epithesis is a recommended alternative in defects of the ear, the nose or the orbital region. Nevertheless problems may arise in the appropriate fixation of the epithesis. With the intermobile-cylinder-implant-system (IMZ), the epithesis is firmly fixed by means of osseointegration of the implants and an abutment in the area of the defect. The various steps of the operation and clinical applications are presented.

[Microsurgical endonasal decompression of the optic nerve]. / Mikrochirurgische endonasale Dekompression des N. opticus.

A new endonasal microsurgical technique for decompression after traumatic optic neuropathy is presented. Compared to the external transethmoidal, the transfrontal or the pterional approach, the main benefit of this method is the superb stereoscopic vision of the medial aspect of the optic canal. The nerve is approached from a 60 degree to 90 degree angle and continuous suction irrigation allows for safe removal of the bony shell. This surgery is done via the endonasal route and therefore has fewer serious complications compared to intracranial, extradural or intradural approaches. Additional trauma due to retraction of the brain is avoided. The anterior ethmoidal cells and the nasofrontal duct remain untouched, avoiding late mucocele formation.

[Regional lymph node metastases in malignant tumors of the head and neck: value of diagnostic procedures]. / Regionäre Lymphknotenmetastasen maligner Kopf-Hals-Tumoren: Wertigkeit diagnostischer Verfahren.

Sonography and computed tomography are used in staging of lymph nodes of patients with head and neck cancer. The accuracy of sonography (90%) and computed tomography (85%) is comparable or better than the palpatory accuracy (85%). The better delineation of reactive swollen cervical nodes leads to a higher sensitivity of sonography (90%) and computed tomography (84%) versus palpation (74%), but a lower specifity (palpation 94%, sonography 90%, computed tomography 86%). A literature survey shows that sonography, computed tomography and magnetic resonance imaging of cervical lymph nodes are comparable good methods.

[Cervical lymph node metastases: a histologically controlled comparison of palpation, sonography and computed tomography]. / Halslymphknotenmetastasen: Histologisch kontrollierter Vergleich von Palpation, Sonographie und Computertomographie.

Sonography and CT were used pre-operatively for lymph node staging in patients with head and neck malignancies. The accuracy of the imaging methods surpassed that of palpation (palpation 85%, CT 85%, sonography 90%). Sensitivity was significantly increased from 74% (palpation) to 84% (CT) and 90% (sonography), ie. there was a reduction in false negative findings. Size of lymph nodes was not closely correlated with metastatic involvement. Reactively enlarged lymph nodes were more easily defined by CT and sonography than by palpation. This reduced the specificity of sonography (90%) and of CT (86%) compared to palpation (94%).

[Compression pneumatocele of the lacrimal sac]. / Kompressionspneumatocele des Tränensacks.

Case report on a 39-year-old man who for five years suffered from a recurrent, firm, crepitant swelling in the medial canthal region after coughing and sneezing. The swelling could be eliminated by digital compression. During a severe bout of sneezing a walnut-sized swelling suddenly occurred which could not be eliminated by compression. Echographic and intraoperative findings confirmed the diagnosis of a large, diverticulous pneumatocele that had compressed the lacrimal sac to such an extent that the entrapped air could not escape. Endoscopy of the nose revealed a wide nasolacrimal ostium, without a Hasner's valve. It was thus possible for air to flow back into the lacrimal drainage system from the nasal cavity.

[Palpation and sonography of lymph node metastasis of the neck]. / Palpation und Sonographie von Halslymphknotenmetastasen.

In a retrospective study, the diagnostic value and ranking of preoperative palpation and sonography for the identification of cervical lymph nodes was assessed in 130 patients with tumours of the head and neck. The diagnostic accuracy (85%) of palpation is below that of sonography (90%). The importance of sonography lies in reducing false negative findings. The increase in sensitivity (palpation 74%, sonography 90%) is, however, offset by an increase in false positive findings, i.e. by a reduction in specificity (palpation 94%, sonography 90%).

[Differential echographic diagnosis of salivary gland tumors]. / Echographische Differentialdiagnostik bei Speicheldrüsentumoren.

76 patients with tumorous swellings of the salivary glands were examined by means of standardized A-scan and B-scan sonography. B-scan echography allowed a differentiation between benign and malignant tumours in all cases. Analysis of the various A-scan criteria (internal structure, reflectivity, borders, consistency and sound attenuation) provided a pathognomonic combination of these criteria for each lesion, enabling further histological diagnosis.

Variations in human corpus callosum do not predict gender: a study using magnetic resonance imaging.

Controversy exists in the neuropsychological literature concerning the existence of gender-associated differences in cognitive functioning and in hemispheric lateralization of cognitive functions. A recent study, based on 14 brains obtained at autopsy, reported sex differences in the splenium of the human corpus callosum and suggested that the larger splenium in females reflects less hemispheric lateralization, or "specialization," than the male brain for visuospatial functions. Our measurements of the human corpus callosum using magnetic resonance images of 37 living subjects failed to confirm reported sex differences in the splenium. A marginally significant sex-related difference in minimum body width and an age-related decrease in anteroposterior distance were found. Most striking were the large variations in callosal size and shape among individuals regardless of age or gender. Existing knowledge of the functions of the corpus callosum does not permit correlations between variations in callosal size and shape and variations in cognitive functions.

[Echographic diagnosis in tumors of the paranasal sinuses with invasion of the lacrimal ducts]. / Echographische Diagnostik bei Nebenhöhlentumoren mit Einbruch in die Tränenwege.

In 16 patients the histologically proven diagnosis of a lacrimal sac tumor was made; in 9 of them a paranasal sinus tumor had invaded the lacrimal pathways, in 7 patients existed a primary tumor of the lacrimal sac, A- and B-scan sonography allow a clear-cut differentiation of both these entities. Furthermore primary and tumor-related inflammations of the lacrimal pathways can be distinguished by echography, which thereby provides the decisive diagnostic basis for the different therapeutic procedures in each case.

Medial preoptic sexual dimorphisms in the guinea pig. I. An investigation of their hormonal dependence.

The guinea pig exhibits sexually dimorphic patterns of cell density and distribution throughout the medial preoptic area, a region that has been shown to be involved in the regulation of sexually differentiated behavioral and endocrinological reproductive functions (Bleier et al., 1982). The most prominent sex differences involve 2 components of the medial preoptic nucleus (MPN), an anteriorly placed compact subnucleus (MPNa) that is twice as large in females as in males, and a centrally placed compact subnucleus that occupies an approximately 10-fold greater volume in males than in females and corresponds to the sexually dimorphic nucleus described in the rat by Gorski et al. (1978). In the present study the sex differences in both of these cell groups were shown to be unaffected by neonatal gonadectomy and postnatal hormonal manipulations. In contrast, MPNa volume was significantly decreased and MPNc volume significantly increased in genotypic females exposed to testosterone propionate (TP) on gestational days 28-37 or 28-65 but not 38-65. All 3 prenatal TP treatments administered to females significantly increased mounting frequencies and suppressed lordosis, ovulation, and the positive-feedback effects of estrogen and progesterone on luteinizing hormone release. Thus, the volumetric sex differences in MPNa and MPNc alone do not seem to be sufficient to account for the sex differences in the functions of the medial preoptic region. It is, therefore, suggested that androgens continue to exert organizational influences upon the developing brain after cytoarchitectonic patterns have been determined.

[Bacteriological, clinical, and pharmacokinetic studies of perioperative antibiotic prophylaxis in head and neck surgery]. / Bakteriologische, klinische und pharmakokinetische Untersuchungen zur perioperativen Antibiotikaprophylaxe in der Kopf-Hals-Chirurgie.

The point of this study was to analyze the possible benefits of perioperative antibiotic prophylaxis in patients from whom oral cavity or throat tumors are removed. The criteria used to judge the efficacy of each treatment included the clinical course of the treatment, the bacterial colonization of the surgical area as well as the growth of bacteria during the postoperative phase. 50 patients were chosen and grouped according to their surgical treatment: laryngectomy (n = 20), partial laryngectomy (n = 22) or tongue, floor of the mouth, soft palate, gum or base of the tongue partial resection (n = 8). Within each surgical group, patients were randomly chosen for antibiotic prophylaxis; others constituted the untreated control group. The antibiotic prophylaxis consisted of 5 g Mezlocillin administered at the time of narcosis for 20 min followed by 0.5 g Metronidazol for 10 min. These medications were given in 8-hour intervals for three days following surgery. Investigation of the first 20 patients (prophylaxis group n = 7, control group n = 13) revealed that the combination of Mezlocillin and Metronidazol positively influenced post-operative recovery (no complications) while the patients without prophylactic antibiotic treatment suffered general or local complication leading to, in 10 cases, the necessity of postoperative therapy. On the basis of these results, the random grouping of the patients was ended and all 30 remaining patients were given the antibiotic prophylaxis. Regardless of antibiotic treatment, the great majority of microbes isolated from throat swabs and tracheal secretions were gram-negative, aerobic bacteria. A prerequisite for efficacious prophylaxis is that the antibiotics be applied before the operation, so that a sufficient concentration is present at the time of pharyngotomy. On the basis of pharmacokinetic investigations, administration of the antibiotic 30 min preoperatively fulfills this requirement. Further, our recommendation, based on our measurement of the spectrum of bacteria present and their growth is that the antibiotics be applied over a period of three days postoperatively. This recommendation is also based on the fact that some patients (those having undergone partial laryngectomy or tongue, floor of the mouth, base of the tongue partial resections) have suffered loss of the swallowing reflex so that there exists a continuous contamination of the surgical area with pathogens or facultative pathogens coming from the nasal or oral cavities.

Intraventricular neuronal complex of the lamina terminalis of the mouse.

An intraventricular neuronal complex has been identified with scanning and transmission electron microscopy at the base of the lamina terminalis of the mouse. The raspberry-shaped complex protrudes from a thickened bulge on the ependymal surface of the lamina terminalis or adjacent rostral floor of the third ventricle. Neurons and occasional ependymal cells cover the surface of the complex. Its core is made up of neurons, ependymal cells, and neuronal processes, which are usually compactly arranged. The core is continuous, through a breach in the ependymal layers, with the subependymal neuropil of the lamina terminalis. Within the core of the complex are large numbers of axodendritic synapses. Axonal varicosities and synaptic terminals are filled with vesicles and mitochondria. Synaptic endings have one of two populations of vesicles: exclusively clear, small, round or flattened vesicles. In view of the known structural and functional characteristics of the lamina terminalis, it is possible that the neuronal complex may participate in neurohormonal regulatory systems of the hypothalamus and hypophysis or in the network of circumventricular organs mediating angiotensin effects.

[Echographic diagnosis in injuries of the paranasal sinuses]. / Echographische Diagnostik bei Nasennebenhöhlen-verletzungen.

A-scan and B-scan sonography was performed in 86 patients with fractures in the paranasal region (73 blow-out, 8 ethmoidal, 5 frontal sinus fractures). In all of them echography provided a correct diagnosis by delineating fracture lines and bone fragment dislocation. Additionally, sonography detected a haematosinus in 17, and a subperiosteal haematoma in 6 patients, respectively. Although echography can never replace radiologic diagnostics, it should be performed in the primary evaluation and in the follow-up of all patients with paranasal traumatology because of its high accuracy.

[Echographic diagnosis in orbital mucoceles]. / Echographische Diagnostik bei orbitalen Mukozelen.

Sonography in 68 patients with orbital mucoceles revealed the following, pathognomonical A-scan criteria: Regular structure, low to extremely low reflectivity, sharply outlined borders, bony defects, missing or minimal compressibility and typical location in the supero-nasal anterior orbit. The echographical findings of "mucoceles" secondary to paranasal tumours are specially emphasised. Echography proves to be a very useful method in the detection and differentiation of orbital complications in paranasal diseases.

[Echographic diagnosis of the ethmoid sinus. II: Clinical findings]. / Echographische Diagnostik des Sinus ethmoidalis. II: Klinische Befunde.

We report on our first clinical results of the echographical examination in ethmoidal diseases using the transocular sound beam direction, and present the A- and B-scan findings in ethmoidal inflammation, mucoceles and tumours. If bony defects in the medical orbital wall and orbital involvement are present, standardized A-scan sonography enables us not only to detect, localise and measure, but also to differentiate various ethmoidal tumours.