Les Cahiers de prothese最新文献

The comparative study of the gingival aspect of dentures made from different flasking procedures, using scanning electronic microscopy, permits the differences in the surface texture of the resins to be assessed. This surface texture will show specific aspects for each technique. The Futurajet resin presents a surface texture with cracks of 100 microns to 200 microns long and 5 microns wide. The appearance of the polymer pellets reveals a good cohesion amongst them. The Futuracryl 2000 resin has an overall surface like an orange peel, with a hills and valleys revealing a rather weak attack of the monomer on the polymer. The palatal surface of the SR-Ivocap resin shows pleats and perpendicular fractures. The surface of the buccal aspect of the ridge is relatively smooth. The Lucitone resin shows a surface with very few irregularities, in which the polymer pellets are well dissolved. In conclusion, no porosities are found on the surface of the various resins. We think that the chemical composition of the resin influences this surface texture and the flasking technique being able to disturb the surface of the resin.

The prosthetic treatment of edentulous patients must be carried out with the dual objective of preserving the residual ridges and re-establishing the functional activities of the masticatory system. The authors propose to investigate the subjective efficiency of the prosthesis by an interview of the patients, and the objective efficiency by clinical testing, after one year of use. In this study, a group of 41 patients, males and females, are supplied with bimaxillary full dentures according to GERBER's technique. Special attention is given to the teeth position in relation to the base stabilisation surface. The teeth likely to unbalance the prostheses were not mounted. The inter-maxillary relationship at the horizontal level was obtained by using a gothic arch recording. After one year of use, the following results were obtained: patients very satisfied with their upper denture: 43.9%; patients very satisfied with their lower denture: 39%; satisfied: 51% for the upper denture; satisfied: 56.1% for the lower denture; not satisfied: 4.9% for the two dentures. Only 12 patients (29.2%) had all of their posterior teeth put in. The decrease in the number of teeth did not reveal any significant decrease in the mastication efficiency, according to the patients opinion (2.4%). The original occlusion was restored in 78% of the cases. The authors emphasized the importance of the occlusal relationship and of the posterior teeth for stability and efficiency in the treatment of edentulous patients.

Removing an anatomical cast post requires many precaution and, in most situation, gives very good results. Nevertheless, this procedure can be dangerous for the tooth or the surrounding tissues and must be considered only in case of absolute necessity. Two techniques are described using a little hole made in the coronal part of the core. A threaded wire is driven through this hole making possible the use of a crown remover. For the second technique the use of an original appliance, the ATD bridge remover, is demonstrated with very good results too.

First the various physical factors involved in retention are discussed. Adhesion is designed by the Gibert formula: [formula: see text] bringing the notion of interfacial surface delimited by the fluid meniscus (epsilon) and the thickness of the salivary film at the site of formation of the meniscus (h). Atmospheric pressure plays a role by the formation of a periphery seal ensuring the creation of a depression of the interfacial fluid in order to oppose the forces of pulling. As a summary, it is important to achieve the formation of a salivary meniscus: with the smallest curvature; continuous despite the mobility of the mucosa; beyond the limit between the free mucosa and the attached mucosa and the "farthest" possible from this area. The purpose of recording the periphery borders is to obtain the highest and widest possible denture flanges without any over-extension or over-thickness. The authors then propose performing a comparative study of the various materials available for recording the periphery of maxillary full dentures, in order to determine which best responds to the criteria of quality mentioned. Several recording techniques are possible, depending on the material used: either a segmented border recording (widely described); or a recording of the periphery seal in one or several stages which is then illustrated by the use of Impregum. For each patient, recordings of the periphery was made according to a protocol always identical and precise; only the material used for this purpose (Kerr compound, regular Neo-Plex and Impregum) varied. The measure taken from these recordings showed that Impregum demonstrates the highest and thickness borders as opposed to Neo-Plex and Kerr compound which provided intermediary results. Thus, Impregum appears to be the material of choice for the optimal recording of the functional periphery seal in maxillary full dentures.(ABSTRACT TRUNCATED AT 400 WORDS)

The patient presented an important bone loss in the edentulous area 21 to 23. The 11 had a temporary crown and a removable prosthesis has replaced the anterior missing teeth. The orthodontic treatment of this class II division 1 was to be undertaken in order to reduce the maxillary proalveolie and to line up the mandibular incisors. The difficulty of the orthodontic treatment was due to the importance of the anterior edentulous area which did not allow a continuous multiring treatment but a bilateral one and a succession of anterior removable prosthesis as anchoring points. The temporary crowns on osseointegrated fixtures replacing 22 and 23 were used to obtain the final orthodontic movements needed in the orthodontic preprosthetic treatment. However, if the fixtures had been placed at the beginning of the treatment in order to use them among other anchoring points, the complete orthodontic treatment would have been faster and much easier. At that time, our major handicap was to determine the ideal position of the fixtures which would allow the orthodontic application as well as a successful cosmetic fixed prosthesis. The use of scanner, three dimensional reconstruction Scanlam, surgical stents and fixed prosthesis with inlay cores would have brought the solution to this problem. Today, the use of osseointegrated fixtures can be applied in much more complex orthodontic movements.

This paper describes the rationale as well as some of the therapeutic tools which may be used during simple preprosthetic orthodontic movements. First a typical bracket is examined: the overall design, the base, the slot and the tie-wings. All those components allow mechanical force transmission from the archwire to the tooth in all three orders of movement. In the classic "edgewise" form of treatment, final placement of the teeth is determined by the bends incorporated into the archwire. Conversely, in the more recent "straight-wire" approach, the angulation of the slot relative to the bracket base provides for an optimal positioning of each individual tooth on the dental arch. Mesio-distal angulation of the roots being referred to as "tip" and bucco-lingual angulation as "torque". The bracket also allows bodily bucco-lingual tooth placement relative to the dental arch as a whole (in-out). Prior to a comprehensive treatment, brackets are placed on teeth according to a standard set of criteria. They must be located midway mesio-distally on the buccal aspect in accordance with the true anatomic longitudinal axis of the root. Its occluso-gingival position however can be slightly adjusted according to the individual needs of the case. In more limited situations, where only a few teeth are moved, those rules have to be adapted since the anchorage teeth are kept stable. Examples are presented which illustrate the key features of limited orthodontic movements. Archwires present themselves in various sections and alloys. The most commonly used metals are stainless steels and the more recently introduced nickel-titanium superelastic alloys.(ABSTRACT TRUNCATED AT 250 WORDS)