Biomedical subjects
Publications and source records attributed to G Cavalleri.
The attempt of Carati and Galgani [Phys. Rev. E 61, 4791 (2000)] to derive the Planck formula as though it were due to long relaxation times is shown to be correct only if there is a single temperature and therefore no transients.
We investigated a radiotherapy-induced flare and subsequent clearance of skin lesions of a patient with the rare, dominantly inherited genodermatosis, Darier's disease (DD). The DD gene, ATP2A2, was recently isolated and shown to be a cation pump responsible for regulating intracellular calcium homeostasis. A severe exacerbation of Darier's skin lesions developed within the radiation field when 40 Gy of palliative thoracic external-beam radiation therapy and concurrent chemotherapy (cisplatin and hydroxyurea) were delivered for non-small cell lung cancer. The DD lesions subsequently completely cleared from irradiated skin, as they did when a subsequent course of radiation alone was given for a loco-regional tumor recurrence. The two radiation therapy-treated areas of skin remained free from lesions of the skin disorder until the patient's death from progressive lung cancer 9 months later. The nucleotide sequence of the patient's ATP2A2 gene was determined by PCR-based cycle sequencing. We identified four nucleotide sequence variants in the ATP2A2 gene in this patient. Three were probable polymorphisms and the other appeared to be a novel disease-causing mutation (R751Q), situated in the transmembrane portion of the ATP2A2 protein. This finding confirmed the clinical diagnosis. Since epidermis turns over every 3-4 weeks, total and persistent clearance of the DD lesions by chemoradiotherapy suggests that this treatment induced sustained differentiation of the DD-affected skin by an unknown mechanism. Oncologists treating malignant disease in patients with DD should anticipate temporary deterioration in DD-involved irradiated skin. Radiation therapy has therapeutic potential in severe DD.
Our paper [Phys. Rev. E 58, 2505 (1998)] described experimental results that brought into agreement standard theory and experiment, in contrast to two previous experiments that claimed disagreement. The shape of our circuit was designed to improve knowledge of the electric flux lines. Such a shape required numerical calculations to predict the relevant force on the mobile part of the circuit.
Using composite resins in posterior esthetic restorations has become more acceptable in recent years as a result of improvements in materials. For this reason, innovative products such as Luciwedge and the SuperMat System have gained the attention of many practitioners. SuperMat, an improved translucent matrix, offers a new approach to matrices for use with multimaterial fillings. It makes the procedure easier and offers many other advantages, particularly in composite-compomer restorations.
The aim of this study was to assess the cytotoxicity of pure eugenol in an in vitro method by diluting it to various concentrations in alcohol and determining the maximum noncytotoxic concentration. We used solutions of eugenol and ethyl alcohol that are soluble in water in any given proportion. The cytotoxicity of the alcohol itself was determined by using a dose-response curve for concentrations of between 0.017 M and 1.7 M. Various strength concentrations (0.015 to 947 microM) of eugenol in alcohol were prepared; 20 microliters (0.34 M) of ethyl alcohol was added to 1 ml of cell medium. The experiment showed that pure eugenol is toxic for human gingival fibroblasts. Eugenol in an alcohol solution at concentrations of < 1.9 microM is noncytotoxic.
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Cell cultures of human gingival fibroblasts obtained from healthy patients were used to evaluate the toxicity of six different endodontic cements: AH-26, Pulp Canal Sealer, Rocanal-R2, Rocanal-R3, Bioseal, and Endomethasone. The toxicity was determined by measuring spectrophotometrically at 405 nm the colorimetric reaction of N-acetyl-beta-hexosaminidase, an endogenous enzyme, with the chromogenic substrate [p-nitrophenol-N-acetyl-beta-D-glucosamide (NAG)]. Severe cytotoxicity was observed in the 1- and 2-wk test solutions of AH-26. Pulp Canal Sealer and Endomethasone showed low cytotoxicity in the 1- and 2-wk test solutions at 24, 48, and 72 h. Moderate cytotoxicity was observed in the 1- and 2-wk test solutions of Bioseal, except at 48 and 72 h of 1-wk test solutions. Rocanal-R2 showed severe cytotoxicity in the 1-wk test solutions at 48 and 72 h, and in the 2-wk test solutions at 24, 48, and 72 h. Moderate cytotoxicity was seen in the 1- and 2-wk test solutions of Rocanal-R3 only at 24 h.
A follow-up study of crown fractured permanent incisors with incomplete root formation was carried out in a group of patients, aged 6-12 years, over a 5-year period in the Dental Clinic of the University of Verona, Italy. The number of injured patients was 55, representing 84 injured incisors. All patients were followed clinically and radiographically using a standardized follow-up protocol. The most common type of trauma was fracture of enamel and dentine without pulpal exposure (80%) and the most common type of treatment was restoration with the acid-etch composite resin technique (46%). Bonding of the crown fragment was performed in 10 instances (12%). At the 5-year-control all teeth with fracture of the enamel had no pulp complications. Four of 67 teeth (6%) with fracture of the enamel and dentine without pulpal involvement showed pulp necrosis and 1 tooth showed pulp obliteration (1.5%). Eight of 14 teeth (57%) with fractures of the enamel and dentine with pulp involvement showed pulp necrosis. Aesthetically 36 of the restored teeth were deemed satisfactory (43%). In 9 teeth the bonded fragment had to be rebonded. 14 teeth were considered unsatisfactorily restored due to wear of the composite (17%). 34 restored teeth had to be retreated because of a new trauma (40%). In one tooth a previous bonded fragment had to be rebonded. These results confirmed that crown fractures without pulp involvement in permanent incisors with incomplete root formation hav a low percentage of pulp complications, while 60% of the teeth with crown fractures with pulp involvement had pulp complications.
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In a previous clinical study regarding the incidence of caries and the periodontal health, a group of young patients with various levels of glyco-metabolic control was studied and the results showed that the decayed-missing-filled teeth (DMFT) index was higher in insulin dependent diabetes mellitus (IDDM) type 1 patients with a poor glyco-metabolic balance than in a control group or in IDDM patients with sufficient glyco-metabolic balance. In light of these results, the purpose of this study was to find an explanation for these clinical observations by searching at a microbiological level. The results indicate that salivary counts of Streptococcus mutans and lactobacilli were higher in patients with active caries whether or not they be diabetic, than in people with no active caries, but the count of S. mutans was not directly correlated to the DMFT index. No significant alterations were found in salivary flow, pH, buffer capacity and glucose concentration in all the groups in this study. We conclude that the salivary count of S. mutans is not sufficient alone to account for the higher susceptibility to active caries of young IDDM patients with poor glyco-metabolic control.
The prevalence of traumatic injuries to permanent incisors and their distribution according to type and some clinical factors, were analysed in a total population of 2798 patients, aged 6-21 years, examined over a 5-year period in the Dental Clinic of the University of Verona, Italy. The material consisted of case histories and radiograms taken during the examination of injured teeth. The number of injured patients was 178 (131 males and 47 females), the number of injured incisors was 326. The prevalence of injuries was 7.3%. A very large number of dental injuries occurred to children aged between 6 and 13 years. The ratio of boys to girls was 2.7:1. Most frequent causes of injuries were falls and traffic accidents. Most injuries involved two teeth. About 80% of the teeth were maxillary central incisors. The most common type of injury was non complicated crown fracture. In 87 cases (48%) there was an associated injury to soft tissue. Alveolar fractures occurred in 22 cases (12%). Traumas involving periodontal ligament constituted nearly 40% of the total. This study noted the following points: 1) preventive education programs should be instituted in the region, directed at parents and school teachers, to inform them about the problems of dental trauma and to obtain cooperative attitude to treatment and good motivation in controls; 2) the necessity to unify the diagnostic and therapeutic protocol to provide reliable information in clinical investigations, to permit valid comparison with other studies and to improve the long-term prognosis of many cases.
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Glutaraldehyde is a potent sterilizing agent with a very broad-spectrum of biocidal activity including Gram-positive and -negative bacteria, spores and viruses such as HBV and HIV (the aetiological agents responsible for hepatitis B and AIDS, respectively). The aim of this study was to evaluate, in experimental conditions simulating the operative risk in dental practice, a 2% potentiated acid glutaraldehyde-based product (DIBA-GLAXO) not only in the disinfection and sterilization of the water circuits of dental units, but also with regard to physico-chemical compatibility, as well as from the toxicological viewpoint. DIBA, in the dental unit disinfection cycle, proved capable of destroying the bacterial cultures of all 16 pathogens used to contaminate artificially the water circuits of the unit handpieces. When the contamination was produced using bacterial spores, 5 hours of contact were sufficient to obtain sterility. The residual concentrations of glutaraldehyde in the circuit washing water, after optimization of the washing process, may be regarded as safe for the patient. Lastly, the product analysed was found to be compatible with the mechanical components of dental unit water circuits. No corrosion phenomena were observed even after total immersion in DIBA for a period equivalent to approximately 20,000 disinfection cycles.
The authors show how the proper use of the root canal medication based on calcium oxide is determinant for causing a perfect asepsis of the root canal in the 58 teeth, taken in consideration, the calcium oxide is more efficacious than the calcium hydroxide not only because it produces a remarkable decrease of the bacterial quantity, but also because the recovery time of the lesion before the filling up of the root canal, is less than half time in comparison with that one got by means of the calcium hydroxide.
Success of endodontic therapy depends upon both operator's skill and quality of the employed instruments. K-files have been examined for they probably are the most commonly used endodontic instruments. It is particularly important to take into consideration, together with the original quality of the instruments, its possible changes due to the wear from sterilization. In this paper have been therefore evaluated the characteristics of brand-new K-files from three different manufacturers together with the wear of the same instruments after paraformaldehyde steam sterilization.
Diagnostic and treatment implications of traumatic root fractures in the coronal third of permanent anterior teeth are reported. A review of the literature imposes a reevaluation of the treatment of these fractures. The teeth with root fractures should not be extracted and endodontic therapy should not be performed unless there is evidence of a pulp necrosis. The authors suggest trying a conservative treatment by repositioning, fixation and relief of occlusion of the teeth with fractures. The fixation is maintained over six months to improve the possibility of recovery. The clinical cases presented prove the long-term prognosis is good even if the location of fracture is near the gingival crevice. The conservative treatment doesn't preclude in case of failure, endodontic, orthodontic and prosthetic therapy. Moreover, according to the authors, conservative treatment represents the most simple, immediate and physiologic solution of functional aesthetic and psychologic problems, especially in young patients.
The changes in the pattern of bacteria in root canal after repeated washing with NaOCl and endodontic instrumentation were evaluated. Samples were obtained from the root canals of patients before and after endodontic instrumentation, and analyzed according to the usual microbiological techniques. Washing with NaOCl and endodontic instrumentation act against bacteria such as Peptostreptococci, Streptococcus sanguis, Actinomyces israelii, Proteus mirabilis, Bacteroides, whereas Streptococcus lactis and Aerococcus were present before and after endodontic instrumentation. Environmental conditions such as low pH could be responsible for the persistence of gram-positive bacteria. The use of topical treatment and the associated endodontic instrumentation seem useful in the eradication of some bacteria in the root canal.