Instruments and armor: flexible rubber bowl, curved spatula, measuring shovel, perforated impression tray, alginate powder and water. The moisture content to which the finished impression is exposed must be controlled. Inadequate storage can lead to syneresis (the material contracts when standing and releases fluid) or absorption (water absorption that occurs unchecked in extent and direction). Therefore, the impression must be stored properly, which means that the material of the set is wrapped in a damp cloth and stored in a sealed polyethylene bag until the impression can be cast. Alginate is used in dental conditions when less precision is required. This includes, for example, the preparation of study casts for dental treatment planning and prosthetic design, but also for the creation of primary and professional impressions for the construction of prostheses. Hydrocolloids (agar and alginate) and polyethers have hydrophilic properties. Therefore, if the disinfection guidelines are not followed, it can cause swelling of the impressions, which, however, if done correctly, does not affect the dimensional stability and accuracy of the impression. Once your dental impressions have been used to make an impression of your teeth, they are usually discarded. However, your dental impressions will be returned to your dentist where they will be kept for a period of time as part of your records. In some circumstances, your dentist may even reuse your dental impressions to perform additional restorations or equipment. Oral to tuberosities, the groove often reaches its lowest point; however, its width is reduced when the mouth is open, because the coronaid process of the lower jaw is close (Fig.
10.9). If the oral flanges of the eventual prosthesis are too wide towards the back, they restrict the opening of the lower jaw or are displaced by the coronaid process. Therefore, the edges of the impression in this area should be shaped to the correct width by the patient moving the lower jaw from side to side with the mouth open. Alginate and elastomers are used to impress oral tissues in partially removable and fixed dentures. Silicones and polyethers with additional polymerization are the most commonly used impression materials in implant prostheses. After removing the tray, the material hardens and goes to a dental laboratory. Although there are constant attempts to improve impression materials, the ideal has not yet been developed. Digitalization in dentistry offers more restorative possibilities, better aesthetics, more efficiency and precision. New avenues for effective and efficient interprofessional and clinical-patient interactions have emerged. Data can be used more effectively for forensic and epidemiological purposes. [33] This digital dental technology (e.g., intraoral scanners and CAD/CAM in practice) is useful for patients and reduces the risk of contamination.
[34] The impression technique may vary from case to case, including multi-mixing, single-phase or putty techniques. [25] The final printing material is supplied in three shapes or viscosities. Figure 10.12 A smaller footprint in alginate shows an edge formed by adjacent tissues. The correct extension in the lingual sacs was achieved by a suitable extension of the tray. The line drawn on the indentation provides useful orientation when the mold is cut. Reversible (physical): impression material, impression waxes, agar-agar. Due to the increased accuracy of elastomers, they are recommended for taking secondary impressions via alginate. Patients preferred both the overall experience of having an impression taken with an elastomer rather than with alginate and the resulting prostheses produced. [5] Alginate is available in two settings: Normal Set, which has a working time of two minutes and a setting time of 4 1/2 minutes, and Fast Set, which has a working time of 1 1/2 minutes and a setting time of 2 minutes. Most offices prefer to use regular alginate to give them more working time. The elastomeric impression material has an elastic or rubbery quality after setting.
These materials are provided as a base and catalyst and are self-curing. Each type of material has different properties and properties. Impression paste is traditionally used to take working (secondary) impressions for a complete denture. When used with a special tray, it needs a distance of 1 mm to allow sufficient thickness of the material. This is also known as a well-fitting special tray. [3] Available as a two-paste system: If you have impressions made with conventional dental putty, the material usually binds in about three to five minutes. Overall, a dental impression procedure takes about 15 minutes or less. Interprofessional teamwork is the backbone in all areas of dentistry. A well-planned, seamless and coordinated deployment of dentists, dental assistants and technicians is essential to ensure the best treatment.