Relationship between accessory foramina and tumour spread in the lateral mandibular surface.
The spread of tumour cells to the mandible has been well recognised and invasion of the edentulous alveolar ridge by tumour through accessory foramina has been documented. Tumour infiltration can also occur through the lateral cortical plate, but the number and distribution of accessory foramina on this surface has not been reported. Lateral surfaces of 89 mandibles were examined and accessory foramina which showed a direct communication with the underlying cancellous bone were charted. It was found that the number of accessory foramina varied greatly from specimen to specimen. Only 70.8 % of mandibles showed foramina in the coronoid, sigmoid and condylar sections; of these 93.7 % exhibited foramina in the condylar section, 23.8% in the coronoid and only 19 % in the sigmoid section. This finding confirms that the current practice of conserving part of the ascending ramus posterior to the coronoid process following surgery is sound. Similarly in the rest of the lateral surface, foramina were present in the upper third section in 97.8 % of mandibles, 61.8% in the lower third and 58.4 % in the middle third sections. This result justifies the principle of rim resection in appropriate cases and the recognition that the alveolar section is commonly invaded before the rest of the body. The number and distribution of foramina may be of greater significance following radiotherapy when the foramina could provide multiple direct channels for invasion of tumour cells from the lateral surface to the medulla. (+info)
Post-extraction remodeling of the adult mandible.
Following tooth loss, the mandible shows an extensive loss of bone in some individuals. This may pose a significant problem in the prosthodontic restoration of function and esthetics. The many factors which have been proposed as being responsible for the inter-individual variation in post-extraction remodeling mean that a perfunctory analysis of the literature, in which well-controlled, relevant studies are scarce, may not provide the whole story. This article reviews the local and systemic factors which may play a role in the post-extraction remodeling of the mandible. Since severe residual ridge resorption may occur even when the bone status in the rest of the skeleton is good and vice versa, it is concluded that local functional factors are of paramount significance. It is now essential to determine how they can be modified and applied to help maintain ridge height and quality in our aging, edentulous population. (+info)
Oral healthcare in transition in Eastern Europe.
Big changes have occurred in the oral healthcare delivery systems of most Eastern European countries since the fall of the Berlin wall in 1989 and the demise of communism in the former USSR in 1991. In the new situation it was necessary to reform the political and social systems including healthcare. Reforms were started to improve the economy and, in comparison with Western Europe, the generally lower living standards. It is difficult to obtain comprehensive data on oral healthcare in Eastern European countries but this paper reports data from nine countries and provides a 'macro' view of the current situation in these countries. Many countries seem to have adopted a Bismarckian model for the provision of oral healthcare based on a sickness insurance system. (+info)
A multi-centre study of Osseotite implants supporting mandibular restorations: a 3-year report.
This multi-centre study evaluated the performance of the Osseotite implant in the mandibular arch. Osseotite implants (n = 688) were placed in 172 patients; 43.5% were placed in the anterior mandible and 66.5% in the posterior mandible. Fifteen per cent of the implants were placed in soft bone, 56.9% in normal bone and 28.1% in dense bone. During placement, 49.9% of the implants were identified as having a tight fit, 48.6% a firm fit and 1.5% a loose fit. About one-third of the implants (32.4%) were short (10 mm in length or less). After 36 months, only 5 implants had been lost, for a cumulative survival rate of 99.3%. The 3-year results of this study indicate a high degree of predictability with placement of Osseotite implants in the mandibular arch. (+info)
Good occlusal practice in removable prosthodontics.
The loss of teeth may result in patients experiencing problems of a functional, aesthetic and psychological nature. This section addresses the very important subject of occlusal considerations for partial and complete dentures. The occlusion is particularly important given the bearing that occlusal factors have, especially on edentulous patients. (+info)
The effect of increasing vertical dimension of occlusion on facial aesthetics.
AIM: To investigate the effect of increasing the vertical dimension of occlusion on facial aesthetics. SETTING: General practice. METHOD: Questionnaires were sent to 96 patients who had been treated in the practice during the period of July 1998 to December 2000, resulting in an overall 72% response rate. All these patients had had their occlusal vertical dimension increased. Photographs of patients were taken before, during and after treatment. The questionnaire asked their opinion on the effects of the treatment on their facial features. To obtain an objective view to substantiate the opinions of the patients, a panel of five judges reviewed the before and after photographs and filled in their own questionnaires. RESULTS: Of the patients who responded to the questionnaire, 79.7% said they looked younger after the treatment. The panel thought 81.2% of the patients treated whose photographs they reviewed looked younger. CONCLUSION: Increasing the vertical dimension of occlusion can have far reaching effects on facial aesthetics, not just on the peri-oral areas but on the whole face. (+info)
The milled implant bar: an alternative to spark erosion.
Patients who cannot tolerate total coverage of the hard palate or whose maxillary arches are poorly formed, because of congenital, developmental or surgical defects, may be unable to wear a conventional complete denture. These patients can be successfully treated with implant-supported prostheses that cover only a minimal amount of palatal tissue. With spark-eroded castings, very precise restorations can be constructed to fit such implant supports. However, these castings are so expensive that cost precludes their use for many patients. This article presents an alternative approach, developed with the refined techniques used for removable partial dentures, which can yield results similar to those for spark-eroded castings at a fraction of the cost. The clinical and laboratory procedures involved in this technique are described. (+info)
Cell proliferation and expression of Cbfa-1 in a peripheral osteo-chondroma arising from the mandibular oral mucosa of an edentulous alveolar ridge.
This report describes the proliferation and the expression of Cbfa-1 in a rare case of peripheral osteo-chondroma arising from the mandibular oral mucosa of an edentulous alveolar ridge. Histologically, the lesion consisted of mesenchymal cells with either bone or cartilage tissue in the center. Almost all the tumor cells were reactive for PCNA, however, only the cells around the bone and cartilage tissues were reactive for Cbfa-1. These results suggest that both the bone and the cartilage tissues in this case were produced by mesenchymal cells that originated from the peripheral periosteum of the alveolar ridge. Furthermore, we have shown that immunohistochemical staining for PCNA and Cbfa-1 can be used to investigate lesions with bone or cartilage formation and to distinguish between those produced by osteogenic cells from those that are just reactive and produced by dystrophic calcification. (+info)