Précis

This article outlines the technique for providing an aesthetic replacement for anterior teeth immediately following extraction using a vacuum formed retainer filled with tooth coloured acrylic resin.

Journal of the Irish Dental Association 2013; 59 (5): 258-260.

This technique was presented as a table demonstration at the annual conference of the Irish Dental Association in 2011 for which it received the Moloney Award.

Una Lally

BA BDentSc MFD DChDent FFD

Practice Limited to Prosthodontics and

Part Time Clinical Tutor

The Northumberland Institute of Dental

Medicine,

58 Northumberland Road,

Ballsbridge,

Dublin 4.

T: 01-668 8441

Email: una.lally@hotmail.com

Introduction

Providing an immediate, aesthetic, retentive and comfortable replacement for extracted anterior teeth can be challenging in a limited time frame. Ensuring a replacement is available immediately after extraction requires planning and liaison with laboratory support. This restoration is generally an interim restoration so is ideally inexpensive.

This technique provides a biological advantage during healing as well providing almost immediate and inexpensive replacement of the extracted tooth. The restoration is independent of the soft tissues and entirely tooth borne therefore the retainer may be worn during the healing phase when the bone and soft tissues are remodelling, without loading the area. This device is also easily removed thus facilitating hygiene. There is no reduction in retention as the supporting tissues remodel, negating the need for relining the prosthesis.

Sheridan et al.1 was the first to describe the Essix orthodontic retainer in 1993 and subsequently its use to provide a provisional restoration. Some concern was raised regarding the original design, which only covered from canine to canine as a slight increase in open bite (2.3%) was observed.

Extending the retainer to cover all occlusal surfaces has been recommended to prevent this.

Technique

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1. Make an alginate impression (Hydragum®, Zhermack Spa, Italy; Solo Plus®, Claudius Ash, Hertfordshire, Britain, Fix Adhesive, DENTSPLY DeTrey GmbH, Konstanz, Germany) of the entire arch from which the tooth is to be extracted. With this technique the tooth to be extracted acts as its own mould; therefore, its shape and form should be as ideal as possible prior to impression making. If the tooth is broken or its form could be improved, a quick intraoral mock-up with composite that is cured will suffice prior to the impression.

2. Pour a cast from the impression. Quick setting gypsum (Elite Model Fast®, Zhermack Spa, Italy) is advantageous in general practice due to the speed of setting of the mixture.

3. Make a hole in the palate of maxillary casts (Figure 1) to allow a more even vacuum to be generated around the tooth areas of the cast. The land portion of the cast should be kept to a minimum for the same reason. The hole can be made in the wet gypsum before it has set which avoids generating excessive dust when the hole is drilled out of a fully set cast. Alternatively the hole can be drilled following the completed setting of the cast.

4. Anaesthetise the tooth, extract it and achieve haemostasis.

5. Place a sheet of polypropylene (0.75mm thick1) in the frame of the vacuum forming machine (Essix Vacuum Thermoforming Machine, Dentsply Raintree Essix, Florida, USA) and heat it. If bubbles appear, the material has been overheated. Polypropylene (Essix C+® Plastic, Dentsply, The Hague, The Netherlands) is the material of choice as it provides adequate rigidity without excessive bulk of material.3

6. Once the polypropylene is adequately heated, turn off the heater and turn on the vacuum. Simultaneously lower the heated polypropylene sheet over the cast.  Allow it to cool completely under vacuum for maximum adaptation of the material to the tooth portion of the cast (Figure 2). Due to the rigidity of the set polypropylene, it needs to be sectioned from the cast, which means the cast is not salvageable (Figure 3).

7. Cut small retention holes in the palatal surface of the retainer where the tooth is to be replaced (Figure 4).

8. Fill the space of the extracted tooth with acrylic resin (SNAP® Provisional Crown and Bridge Resin, Parkell Inc, New York, USA) to match the shade of the adjacent teeth (Figures 5 and 6).

9. The vacumn formed retainer is returned to the mouth to allow the acrylic resin set, taking care that the setting acrylic resin does not engage any adjacent undercuts.

10. Smooth the tissue surface of the set acrylic to ensure no tissue contact.

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11. Trim the retainer and acrylic to eliminate any sharp edges. It is not recommended to scallop the retainer to follow the gingival margins (Figures 7 and 8).1

12. Use an abrasive stone to give the final polish. The tissue surface of the retainer should be as smooth as possible and ideally convex to make it cleansable. The patient should be made fully aware of the  short-term nature of this restoration and the need for meticulous oral hygiene emphasised.

Discussion

This technique can be modified to accommodate a patient who presents with an edentulous space.2 In this instance a denture tooth of the correct shape and colour can be placed in the space, a retentive groove (4mm wide by 3mm deep)2 should be placed in the lingual surface of the tooth. Table 1 summarises the indications and contraindications for use of a vacuum formed retainer to restore an edentulous space. Thermoplastic vacuum-formed material has proven quite versatile in prosthodontics including use as a matrix form to fabricate provisional restorations, guiding tooth preparation, radiographic/surgical guides, whitening/fluoride trays et cetera. Table 2 outlines the advantages and disadvantages of using a vacuum formed retainer to restore an edentulous space.

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Summary

This technique can be used as an immediate short-term solution after extraction, implant placement or grafting procedures. Long-term use is not appropriate and it is not suitable where there is poor hygiene or a high smile line where the junction of the flange and soft tissue would be conspicuous. This device is easily removed to facilitate hygiene, it is available almost immediately, is inexpensive, comfortable to wear, conservative of abutment teeth and can be relieved of soft tissue contact. It is not appropriate in situations where occlusal units are required, where multiple teeth are to be extracted, where there are high aesthetic demands or when a long-term solution is required.

References

1. Sheridan, J.J., Le Doux Ward, W., McMinn, R. Essix retainers: fabrication and supervision for permenant retention. Journal of Clinical Orthodontics 1993; 27: 37-45.

2. Sheridan, J.J., Le Doux Ward, W., McMinn, R. Essix technology for the fabrication of temporary anterior bridges. Journal of Clinical Orthodontics 1994; 28: 482-486.

3. Gegauff, A.G., Holloway, J.A. Provisional restorations. In: Rosenstiel, S.F., Land, M.F., Fujimoto, J. (eds.). Contemporary Fixed Prosthodontics. Mosby, St Louis, Missouri; 2006: 384.