Odontostomatologike proodos最新文献

The need of amalgam to resist fracture becomes a more evident necessity when restoration margins are taken into consideration. Marginal microcracks permit bacteria to pass beneath the restoration resulting in cement base dessalution, secondary caries and pulp inflammation. Fracture toughness of amalgam is usually studied indirectly from the maximum force required to fracture the amalgam, during compressive, tensile or bend stresses, through its ability to deform plastically or its surface hardness. Important information on fracture toughness of amalgams can be also taken from metallographic studies of their microstructures, during or after the formation of a crack. This study was planned to evaluate the microcracks produced on the surface of different amalgams, with a Vickers pyramid head of a hardness tester and their relation to the different phases of the amalgam structure. Seven amalgams were studied: Amalcap-F, Tytin, Cupralloy, Ana-2000 and three experimental combinations of them, in order to have in the same amalgam different alloy particles, for evaluation purposes. The result showed that the structure elements, that mainly assist crack formation and propagation, are voids and gamma 2-phase, while elements that resist fracture are alloy particles (gamma-phase) in conventional amalgams, eutectic spheres in admixed high copper amalgams and eta'-phase crystals in single melt high copper amalgams.

The use of the Pindex system for removable dies, were presented in this paper. A detailed classification of the types of die systems has been attempted. The Pindex according to deferend studies is the more precise and ideal method for fabricating removable dies. Advantages of this system include excellent stability of the die and recommended for long spand bridges, where the details are very difficult to produce. The technique of the system has been presented in step by step procedure.

The glass ionomer cements were developed in the early 1970s as filling restorative materials. Today, they have been modified for various clinical applications and the major of them is as base or lining, specially beneath composite resins. This paper is a literature review about the base/lining type of glass ionomers. The composition, the structure and the physicomechanical properties of this type are reported. Also, are presented the possibilities and results of their usage as base/lining in the restorations of amalgam and composite resins.

The aim of this study was to determine the absorbed doses of radiation in the skin region of temporomandibular joint (T.M.J.), maxillary sinus, parotid gland, body of mandible and thyroid gland during 14 periapical radiographs. For this purpose were used: a minim-X, 2000 CIAS international (Kvp:50, mA:10, t:0.1, sec, 0.2 sec), 31 male patients and 31 female patients about the same age, weighing and height who were selected from the Oral Diagnosis Clinic of Athens University, and had indication for periapical dental radiography. The calculation was performed with thermoluminescent dosimeters (T.L.D.) which calibrated by a Known source of Co60 before use. Dosimetry were calculated in T.L.D. detector Model 2000 A-2000 C Harchaw Chemical Co. and the results of calculation which were evaluated statistically using the student t-test, were the following: 1. Dose above 1.00 cGy received the body of mandible region and the maxillary sinus. 2. Dose below 1.00 cGy received the parotid, the T.M.J. and the thyroid region. 3. The male patients received greater doses than the female patients in all anatomical regions which were examined. 4. Doses on the right side were greater than the left side.

The relationship between age and oral hygiene habits as it was defined by the answers in a special questionnaire was studied and evaluated in a group of adult periodontal patients. The answers of 185 patients were evaluated from a total of 987 questionnaires from patients presented for periodontal treatment in the private offices of the authors during the last ten years, consisting a representative sample. The questions related to the personal habits of the patient in relation with the frequency of brushing, the method of brushing, the hardness of the toothbrush, the possibility "of brushing their gums" and the possibility of using additional mechanical aids of oral hygiene. The results showed that the frequency of the everyday brushing is decreasing steadily and progressively from the younger to the older patients. The method of brushing as well as the choice regarding the hardness of the toothbrush that the periodontal patients are using is not influenced by age. However the knowledge of patients regarding brushing the use of additional mechanical aids of oral hygiene except the toothbrush and the value of the toothpaste are statistically significant influenced by the age of the patients. The results of this study confirm that the younger age groups of periodontal patients are more informed about oral hygiene. The greater awareness which is higher in younger patients is possible explanation for these results.

Conventional Endodontic therapy is the treatment of choice for pulp disease and periapical lesions due to pulp necrosis. Although the percentage of success of endodontic therapy is fairly high, in several cases endodontic therapy cannot perform accurately, or it is impossible to undertaken so as to avoid extraction of tooth. Before an endodontic surgery is performed a conventional endodontic therapy must be attempted because this increases prognosis and reduces the possibilities of failure. The possible presence of lateral canals, communication between periodontal ligament and infected canals through dentinal tubules and the potential hermetic reverse filling, are ones of the main factors which support the necessity of endodontic therapy. Apart from these, many cases have been reported where the basic factor of endodontic surgery failure was not the awkward operations, but the absence of the root canal filling. In this paper authors describe the basic steps and techniques which must be followed so as to avoid the failure of endodontic surgery.

A cosmetic dentist designs a smile not solely for form and function but also for the personality, status, life-style, sex or occupation of the recipient. The smile is seen as an integral part of the face or, in a larger sense, of the whole person. The advent of bonding provided the concerned dentist with the means to attach composite resins, in their various shades, to the tooth surface in order to create esthetic illusions or to cover up unsightly teeth. A recent major break through that facilitated predictable retention of porcelain to the tooth surface has added a new dimension to esthetic dentistry. Porcelain veneers can be considered to be very much the "State-of-the-art" in cosmetic dentistry because they offer innumerable advantages over any previous form of veneering systems.

Radiography plays a critical role in the management of traumatic injuries to the facial bones. Injuries of the face and jaws require highly specialized technical treatment that is directed toward the establishment of normal function of the jaws and teeth and the prevention of infection and facial disfigurement. The face and especially the jaws present unusual difficulty in Radiographic examination and many different projections have been described to show the maxilla and the mandible. The clinician should be familiar with these projections in order to achieve useful information. In this study after a brief introduction to the fractures of the middle third of the face, the basic projections for the radiographic examination are presented.

A case of peripheral ameloblastoma is presented which was located in the right maxillary tuberosity area in a 52-year-old caucasian male. The lesion was asymptomatic and presented as a reddish sessile mass of soft tissue, 1.5 cm in diameter, with a granular surface and firm texture (Fig. 1). There was no radiologic evidence of bone involvement (Fig. 2). A clinical diagnosis of squamous cell carcinoma was made and a biopsy was taken. The microscopical examination revealed the presence of ameloblastomatous tissue exhibiting numerous areas of continuity with the surface epithelium (Fig. 3). The tumor showed a mixed follicular (Fig. 4) and plexiform (Fig. 5) pattern and was accompanied by a mild lymphocytic infiltrate (Fig. 3). A partial maxillectomy was performed and the histopathological examination of the surgical specimen confirmed the diagnosis of peripheral ameloblastoma. A primary basaloid pattern of the tumor was identified (Fig. 6) but a search for acanthomatous areas was proved fruitless. Some epithelial islands showed peripheral columnar cells with apically polarized nuclei (Fig. 7). The space between the border of the tumor (Fig. 8) and the underlying bone was filled with dense connective tissue and contained two isolated tumor follicles with cystic change (Fig. 9). The thorough examination of the co-existed bone did not reveal any areas of tumor invasion. Finally, the oral epithelium adjacent to the tumor exhibited elongated and slender rete ridges (Fig. 10). One and a half year post-operatively, no signs of recurrence could be detected.

The purpose of the present review was to present a detailed description of those current scientific results and opinions relative to the biocompatibility of dental amalgam. The first section of the percent review to the pulpar reactions caused by amalgam fillings, especially when no protective base has been used, while the second part concerns itself with the biocompatibility of the dental amalgam per se. Specifically, reference is made to: a) the adverse reactions due to amalgam fillings both on the patient's physiological system and on the dentist's employing the material under consideration. b) those investigation results bearing a relation on the amount of mercury liberated during the amalgam filling procedures, i.e., mixing, condensation, finishing and polishing and/or removal of old amalgam fillings. c) Liberation of mercury, as well as metallic ions in the patients mouth cavity during chewing and/or during the process of intrabuccal galvanization and corrosion, and d) on the amount of mercury traced in the blood and urine of the patient following amalgam fillings. No conclusive evidence on any adverse reactions on the patient's health, attributable to the liberation of mercury from amalgam fillings, could be presented by the scientific investigations under consideration. Moreover, the number of cases reported on toxic reactions due to dental amalgam is negligible compared to the immense number of amalgam fillings performed in practice. It merits mentioning in this connection, however, the fact that the total amount of mercury attained by the patient from any other source, in conjunction with that liberated from amalgam fillings, could by all means contribute to a number of toxic reactions on the patient's health in general. Conclusively, one could state without reservations, that dental amalgam fillings per se are by and large free of toxic reactions on the patient, based on current scientific observations. Mentioning is finally made on several simple but nevertheless imperative precautions for the safety of public health.