Revue d'odonto-stomatologie最新文献

The wash-technic is one of the most well known and most used impression technic when using elastomeric silicones. It is however one of the most criticized technic. The wash-technic depends on Biomaterials and on operative procedures. After reviewing the two types of elastomeric silicones available and the properties that are required for this technic, the author shows that additive materials are reliable and successful when used for the wash-technic. Nevertheless to eliminate all possible deformations due to internal tensions of the materials, it is very important to follow strict operative procedures (specially for the pre-impression preparation), and to respect the contra-indications of this technic.

Individual compartment trays can be used for dental impression in fixed prosthodontics and represent an original method which alleviates the pitfalls of standard technics. This method is based upon a strict adaptation of the tray to both the preparations and the dental arcade using the primary impression. Impression pastes can be used in their optimal conditions using the I.C.T. (Individual Compartment Trays) and a higher definition of cervical limits can be obtained. The use of I.C.T. reduces the risks of interposing free marginal gingival and eliminates the inconvenients of intrasulcular leakage.

Reversible Hydrocolloids impressions are the most simple, easy and reliable of all the available impression technics, when their indications are respected. The precision of this technic, although excellent, can not render this technic universal. The indications and limitations of this technic are directly related to the properties of the reversible hydrocolloids. Good clinical results will depend on: a very good gingival retraction technic (with enough space for the material) and the immediate casting of the impression; the knowledge of the intrinsic qualities and performances of the material during all the clinical steps, without trying to surpass or betray those qualities.

Complete impression with rings achieves the same definition than complete impressions alone and gives a final quality similar to unitary guided impressions. The required steps are the following: 1st clinical: adjustment of the unitary rings, laboratory: elaboration of metallic resin boxing and individual tray, 2nd clinical: complete impression with rings. This method is of a particular interest because of its facility and its possible adaptations to various impression pastes or clinical situations. No gingival conditioning is required to the impression, and increased indications of the method can thus be seen when esthetics or periodontal conditions are a priority.

Hydro-alginates are a combination of reversible and irreversible hydrocolloids. These products are a material choice in fixed prosthodontics and removable partial denture due to their reliability and ease of use, depending on adequate utilization of the materials and on a perfect synchronization during the impression procedures.

For the general practitioner, the superficial periodontal structure is an obstacle when trying to gain access, control and visualization to juxta or infra gingival preparations. A temporary restoration will maintain and protect those limits and in many cases it is a very efficient procedure. Sometimes it is necessary to enhance the gingival preparation by sophisticated methods. There are many different technics available to the practitioner. In this article we will describe the technics with easy clinical use and those respecting the gingival tissue (mechanical, physico-chemical).

Syncopes related to cerebral or cardio-vascular lesions, or resulting from a reflex or from a mixed origin should remain exceptional. Adequate knowledge of their possible etiology and of the curative and preventive measures to use, are very important. To avoid an irreversible issue every practitioner should master the resuscitation technics. Each office should have an adequate equipment for resuscitation and CPR courses should be taken every year.

Although the anterior guidance in complete dentures is not really a guide, the arrangement of the anterior maxillary and mandibular prosthetic teeth, defines a propulsive line called the virtual anterior guidance, a part from the cinematic criterias. The influence of this guide on cuspal movement is superior, in all mandibular points, to the influence of the condylar pathway. If this line is not respected, the practitioner may have to do excessive grindings during occlusal adjustments.

A titanium nitride coating has been deposited on steel and tungsten carbide dental rotary instruments. This process is carried out under partial vacuum, by reacting vapourized metal (titanium) and nitrogen in a plasma. The instruments temperature is around 500 degrees C during coating. We have determined by micro-analysis the treatment modifications upon the different bursa components. VICKERS microhardness tests have shown the coating temperature effects towards the heat treatments of employed steels.