September 1997 • Volume 78 • Number 3


A simple and reliable procedure for routinely capturing vestibular anatomy in preliminary impressions

Jason J. Psillakis, DDSa [MEDLINE LOOKUP]
R. W. Toothaker, DDSb [MEDLINE LOOKUP]
Columbia University, School of Dental and Oral Surgery,
New York, N.Y.


Sections


 

The dental literature has discussed the attention to detail required when making definitive impressions of the edentulous mouth, 1-4 but many operators often do not capture all the patient's soft tissue details when making irreversible hydrocolloid impressions for preliminary or diagnostic casts. When making preliminary irreversible hydrocolloid impressions for diagnostic casts, the clinician looks to capture specific landmarks such as complete vestibular anatomy for proper clasp design and selection (for removable partial dentures) or for better visualization of the available support and undercuts (for complete dentures and implant-supported overdentures). These details are many times overlooked or simply forgotten because they were not captured in the preliminary impressions, yet they remain critical in the treatment plan and definitive prosthesis.

The use of a 20 ml or 30 ml plastic disposable syringe (B-D 30 ml syringe, Becton-Dickson and Co., Franklin Lakes, N.J.), in conjunction with an irreversible hydrocolloid impression tray, is an easy procedure to ensure more detailed preliminary impressions on a consistent basis. There are several advantages to this procedure including the use of less irreversible hydrocolloid in the tray, which will reduce the incidence of gagging and further aggravation of an anxious patient at the initial appointment of many expected appointments. The operator may also use less pressure to allow the irreversible hydrocolloid to flow into the vestibules or other hard to reach places, such as a high palate, the vicinity of the retromylohyoids and the hamular notches, especially for the immediate denture patient. The procedure can also reduce the need for periphery wax to carry the irreversible hydrocolloid to hard-to-reach places.

This article describes a simple procedure that can assist the dentist in routinely capturing vestibular extensions and other hard-to-reach places when making preliminary impressions in both dentate and edentulous patients.


   Procedure  TOP 
  1. Examine the mouth of the patient to determine the extent of the anatomy necessary to capture in the preliminary impression to make a cast to aid in the diagnosis, treatment plan, and fabrication of the prosthesis.
  2. Try in the impression tray to ensure proper fit without impingement on soft tissues.
  3. Make a full mix of irreversible hydrocolloid part and load it into the back end of a disposable 20 ml or 30 ml syringe (Fig. 1) with a scooping motion before the plunger is inserted into the barrel. The tray should be simultaneously loaded with the remainder of the same mix. When the operator is working alone, load the syringe first, then the tray.
  4. Proceed to the mouth of the patient and syringe the irreversible hydrocolloid material into the critical portions for the impressions (Fig. 2) , and immediately place the loaded impression tray in the usual manner.
  5. When the irreversible hydrocolloid gels, remove the tray from the mouth and examine it for defects, making certain that the complete impression has been obtained (Fig. 3) , all the borders, extensions, and details that are needed to make a more accurate diagnosis and appropriate treatment plan for the patient have been captured (Fig. 3) .

Fig. 1. Plastic syringe, 20 ml, used to carry irreversible hydrocolloid difficult to reach portions of arch. Syringe is back-loaded in scooping motion and plunger is then reinserted.
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Fig. 2. Syringe used to carry irreversible hydrocolloid material to mandibular anterior labial vestibule in patient considered for immediate denture prosthesis. Loaded impression tray is then immediately inserted in usual manner.
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Fig. 3. Preliminary impression on left was made in usual manner. Preliminary impression on right was made with plastic syringe procedure used to carry irreversible hydrocolloid material to vestibules, which resulted in more detailed capturing of complete vestibular anatomy in preparation for possible immediate denture prosthesis.
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The disposable syringes are relatively inexpensive, however, they can be cold-sterilized for reuse. It is helpful to have one syringe per arch impression to avoid cleanup time during the procedure. Some clinicians may also prefer to enlarge the tip for better flow, although this has usually been found to be unnecessary.


   Conclusion  TOP 

This simple procedure not only allows routine capturing of all the oral anatomy needed for proper treatment planning, but also requires less quantity of material in the tray, which reduces the tendency for gagging and creating an anxious patient. It also requires less pressure to force the irreversible hydrocolloid to flow into hard to reach portions of the arch and requires no additional chair time. The procedure is inexpensive, simple to use, and may also be applied to the preliminary and definitive impressions for the immediate denture patient when the presence of malpositioned teeth may prevent the capturing of vestibular anatomy with the usual impression procedures by using a tray alone.


   References  TOP 



   Publishing and Reprint Information  TOP