Les Cahiers de prothese最新文献

The purpose of these clinical cases is to show the advantages of coping abutments in fixed and removable partial denture reconstructions. These cases try to gather the largest indications for this technique. The emphasis is put on many positive points of this type of reconstruction: control and easy maintenance via an optimal accessibility to the abutments; may be used in complex rehabilitations combined with other types of attachments; easy insertion of the removable partial denture by the patient; improvement in the prognosis for cases that cannot be treated with fixed prosthodontics and precision attachments. A good aesthetic result can be achieved and gives expectation for an encouraging future for this type of well-made reconstruction.

The experimental protocol developed in the previous article (4) has been modified to permit the investigation of the fluorescence of shade guides. The following will be traced out on each graphic display: a reference spectrum using full lines; a sample spectrum using dotted lines; the chromaticity triangle of the X Y Z CIE 1931 system; the chromaticity of the sample to be tested, represented by the sign +; the chromaticity of the reference, represented by the sign -. The shade guides without any rare earth have spectra in the form of wide bands; their intensity decreases when the degree of colour purity in white light of the buttons increases. The shade guides containing rare earth have spectra with both a wide band and thin lines. It has been shown that: the same shade guide can contain different fluorescence components; two shade guides from the same source can have very different fluorescences for buttons of the same reference; two shade guides from different sources can have identical fluorescent components. This study reveals: that unadapted fluorescences of shade guide may be the cause of an error in the choice of the colour of a ceramic restoration; that the comparison of spectra appears to prove that shade guides are not manufactured by the ceramic manufacturers which recommend them and are, in fact, of the same origin.

This study shows the interest of using a light cured resin for temporary restorations. The rubber like stade enables easy removable of undercuts and excess material can be trimmed easily before light irradiation. Physico-chemical properties of light cured resin are compared with those of four chemical-polymerizing resins. Exothermic reaction, transverse strengths, modulus of elasticity, and differential scanning calorimetry show the same values as the best autopolymerizing resins. The author presents an original technic, using the light cured resin with light cured composites to achieve aesthetic and strong temporary restorations.

This paper sheds light on retention systems using telescope crowns in fixed and removable partial denture prosthodontics. Although relatively old in concept, these procedures are enjoying renewed interest due to the considerable progress made in precision machining at the dental laboratories. The use of these rehabilitations, simple to understand, nonetheless requires absolute precision regarding their achievement. The practitioner and dental technician must bring to this kind of work a maximum of complementarity; communication must be constant for the reciprocal understanding of the problems faced by each of them. It is important to emphasize the ease of application and the number of solutions proposed by these telescope systems which, despite the ever growing quantity of new techniques must be maintained in the prosthetic and therapeutic possibilities.

Although we know that the most favourable situation for preparations margins is above gingiva, it has been proven that in numerous clinical cases, this situation is modified in an apical direction and becomes subgingival. This location of the margins then becomes unfavourable from a periodontal point of view as well as in the control of adaptation. However, the major problem arises when the impression is taken. In fact, the marginal gingiva constitutes an obstacle to the access of the impression material to these margins. Nevertheless, numerous techniques allow the free marginal gingiva to be retracted under such conditions that the principal aim can be reached without injuring the conjunctive epithelio-connection. The procedures used to retract the gingiva are either mechanical, chemico-mechanical or surgical. The mechanical techniques may use copper bands and ring collars, the latter being the procedure of choice when indicated. Another technique uses retraction cords, providing a gingival sulcus enlargement without using impregnated cords with haemostatic or astringent solutions. This last technique, nonetheless, must be avoided if there is a risk that might lead to bleeding when the cord is removed. The second retraction technique uses these same cords impregnated with haemostatic or astringent solutions. It seems that 15.5% ferric sulfate impregnated braided cords represent the procedure of choice, allowing both the retraction of the sulcus and the total absence of bleeding, since haemostasis is ensured definitively via the situ application of the pure product. The final technique is the gingival surgery. It may use Ingraham's diamonds that simultaneously finish the subgingival preparation margins and make a superficial epithelium curettage. Following this surgical retraction, haemostasis is ensured, but the rotative instrument used provides, at once, the best profile of the internal wall of the free marginal gingiva for the impression. The second procedure is electro-surgery which provides constant results when use, thereof, is well indicated. Finally, the CO2 laser can also provide another possibility for surgical retraction. Nonetheless, it seems that the CO2 laser is not the best procedure, given the difficulties in directing it. Depending on the case, all these techniques allow the expected results to be obtained, but, unfortunately, their innocuity is not absolute. In fact, it is proven that following any type of gingival retraction, a lesion is caused both by the practitioner and the equipment used, which thus, leads to a loss of about 1/10th millimeter in the height of the free marginal gingiva.

All prosthetic proposals can be judged only after a lapse of time. After twelve years of clinical practice using the concept of the stress breaker framework the results have been established. The clinical results revealed concern prostheses made according to identical criteria as regards the design (stress breaker framework), kind of prosthetic teeth used, mounting of teeth, imprint technique. The clinical protocol was that used for the comparison and verification, in time, of determined criteria. The criteria used were: the presence of pillar teeth, the absence of re-lowering indication, maintenance of V-O-D. The method involved: 170 cases, 418 pillar teeth, clinical follow-up from 3 to 8 years. The results revealed: preservation of teeth 96% absence of lowering indication 95% maintenance of V-O-D. 95% The analysis of the results shows that the preservation of the tooth pillars and the limitation of resorption below the stress breakers seem to be positive elements which are obtained easily and constantly due to the use of the stress breaker framework used in a movable partial prosthesis.

The authors propose an original method for the setting of a semi-adjustable articulator based on latero-protrusive check-bites. This study compares two setting methods. The first was used as a control. It makes use of protrusion and lateral check-bites for the adjustment of the condylar path angle and Bennett's angle. The second method, adjusts the two parameters using only latero-protrusion check-bites. Recordings were taken on 15 young patients aged from 24 to 32 years old, having a healthy and complete dentition without any subjective symptomatology of T.M.J. The recordings were always made by the same operator. According to a strict methodology, the same protocole was used for the recording of the check-bites with both methods, mounting of the models on the articulator and adjustment of the angles. For the first method, the check-bites were taken with a 5 mm protrusion previously determined on the articulator. This position was reported and marked in the mouth using indelible ink. Likewise, a 5 mm lateral bites position on the working side was determined for both sides. With the second method, the lateroprotrusion bites were taken with a 3 mm displacement of the condyle on the working side and 5 mm on the non-working side. In both methods, the values of the condylar path angle and Bennett's angle were revealed and compared for all the patients. Subsequently to a statistical analysis, the authors concluded on the similarity of the results for the two methods, confirming the interest of a single latero-protrusion check-bite which is easier to obtain, is economical in terms of time, and entails a lesser number of bites to be made.

Today, it is quite easy, even to the unfamiliar practitioner in implantology, to get clear ideas of the surgical stage in treatments where implants are involved. These procedures have been well described and documented, especially by the swedish school. But things are less simple concerning the prosthetical procedures. After a personal experience of years, in this field, both, as oral surgeon and prosthodontist, we think time has come to point out several criterias, leading to long range success. We will review some major aspects of this particular prosthodontics, like: different clinical situations, according to the localisation of edentulism, connections, frameworks and cosmetics, and so on... We are convinced that the respect of these rules is one of the numerous keys of success in today's implantology.

Regardless of the schools or work habits in total prosthesis, the laboratory technician must, following the clinical session of primary imprints, prepare the latter and make models in hard plaster, on which he will develop the individual imprint constructions (IIC). By virtue of a special device developed by the author (the "Lutemat"), the IIC is equipped with two personalized occlusal rings adapted to the particular clinical case, adjusted as of the outset according to the intermaxillary relationships pre-established at the various levels. The final anatomophysiological imprint can be carried out under optimal conditions. Lutemat can be used with most current articulators. It has three principal uses: to permit the spatial orientation of maxillary and mandibular models and to pre-determine the height of the occlusal plan due to adjustable orientation points; to ensure the development of occlusal rings to a predetermined dimension and according to a privilege clinical situation on the occlusal plan, due to a "pocket" instrument; to permit the mounting, on an articulator, of models deriving from terminal anatomophysiological imprints. Following casting of the models and preparing the IIC base, the practitioner places and orients the mandibular model on the Lutemat base. The mandibular occlusal ring is shaped and modeled according to the individual criteria of the patient. The maxillary ring is then made depending on the intermaxillar relationships which were pre-established at the clinical session devoted to the primary imprints. The IIC's obtained using this technique are truly personalized and the later sessions of terminal imprints and recording of occlusion can take place with great ease and comfort.

Two major concerns characterize the difficulties encountered with prostheses on implants. 1--The difference in orientation between the implant, imposed by anatomical requirements, and the restoration anatomy. It should be kept in mind that a sufficient occlusal space is required to house the restoration. The regularization of the occlusal curve of the opposite arch, in the example given, was obtained by bonding ceramic overlays. 2--The visibility of the abutment at the gingival level. In this clinical case, after removing the old prosthesis, it is observed that the position of the screws is unsuitable, as one of them emerges into the embrasure. A solution to these problems may be found in building an intermediate screwed core. The technical protocol requires the use of long screwed transfers, a specific impression method and plastic preforms. The intermediate core is formed by the combination of two hollow dowel cores into which a conventional metal ceramic bridge is incorporated. Aesthetically speaking, the prosthetic construction is characterized by the absence of metal visibility. The use of the pterygoid bone radically transforms prosthetic indications. It is advisable that the extremity of the implant remains accessible. Linking to the restoration can be carried out with a screwed telescopic substructure. It is not necessary, at the level of the pterygoid bone situated outside the limits of the arch, to carry out any dental morphology. A smooth, polished construction situated below the plane of occlusion is sufficient.