Authors: Dr Manesh Lahori, Dr Lanka Mahesh, Dr Swati Loomba

INTRODUCTION

According to the Glossary of Prosthodontic Terms,
A provisional prosthesis is prosthesis designed to enhance aesthetics, provide stabilization and/or function for a limited period of time, and should be replaced by a definitive prosthesis after a period of time.
The interim prosthesis acts as a reference in designing the final prosthesis (Soballe et al 1990)

NEED FOR ESTHETIC PROVISIONAL RESTORATION:

1. To overcome patient’s apprehension of social image.
2. To restore function and phonetics.
3. To achieve an optimal soft tissue profile.
4. To maintain space for the final prosthesis.
5. To protect the Osteotomy site.

FACTORS OF CONSIDERATION WHEN FABRICATING A PROVISIONAL PROSTHESIS:

1. Provisional restoration should not interfere with primary wound closure.
2. It should provide the patient with harmonious occlusion.
3. It should restore esthetics and phonetics.
4. It should protect the underlying gingival tissues.
5. It should not exert any direct biting loads to the underlying implants.
6. Should be out of occlusal contact in centric and eccentric positions.

PROVISIONAL RESTORATIVE MATERIALS:

IDEAL CHARACTERISTICS:

An ideal provisional material should have the following characteristics:-

1. Convenient handling – adequate working time, easy mouldability, rapid setting time
2. Biocompatibility – non-toxic, non-allergenic, non-exothermic
3. Dimensional stability during solidification
4.  Ease of contouring and polishing
5. Adequate strength and abrasion resistance
6. Good appearance
7. Good patient acceptance
8. Ease of adding to or repairing
9. Chemical compatibility with provisional luting agents

 
PROVISIONALIZATION PRIOR TO IMPLANT LOADING

TYPES OF PROVISIONAL RESTORATIONS

1. Removable partial dentures(FIGURE 1)
2. Most widely used option.
3. Indicated in case of long edentulous spans.
4. Also useful where multiple surgical re-entries are planned
5. Inexpensive and easy to fabricate.
6. Also might stimulate bone remodeling around implants in completely edentulous patients. (Lewis et al 1995)
7. Limiting in function and phonetics due to instability.
8. May sometimes be detrimental to underlying soft tissue and cause implant exposure or marginal bone loss.

FIGURE 1: REMOVABLE PARTIAL DENTURE

1. Essix appliance(FIGURE 2)
2. The Essix appliance (Essix-Retainer), is a removable, temporary restoration.
3.  A vacuform shell of the arch is fabricated from a stone model, prior to the extraction of a tooth.
4.  The crown of the extracted tooth may be bonded into the retainer, or more commonly, tooth colored resin fills the space previously occupied by the crown of the extracted tooth.
5.  This appliance should fit snugly over the remaining teeth in the arch, which prevents unfavorable displacement or movement over the implant site/s.
6.  Protects the underlying soft tissue.
7. Improper use may cause occlusal wear under vacuform material.

FIGURE 2: ESSIX RETAINER

FABRICATION OF AN ESSIX RETAINER

• Glass fiber reinforced composite resin (FIGURE 3)
• Time to insertion relatively short,
• More esthetic
•  Minimal tooth preparation
• Good flexure strength
•  The light-polymerized FRC substructure retains a sticky oxygen-inhibited layer on its external surface that allows direct chemical bonding with the covering composite.
• Functional stresses and occlusal loading of the pontic should be minimized
• Vertical and horizontal overlap should not be greater than 3 mm, and the supporting abutment teeth must be structurally vital and intact to serve as abutments for the fiber-reinforced matrix.

FIGURE 3: PROVISIONALIZATION USING GLASS FIBER COMPOSITE

• Adhesive bridges(FIGURE 4)
• A more esthetic and acceptable option
• Totally tooth supported.
• Cannot be used in long edentulous spans
• Mainly indicated for anterior single tooth cases
• Not suitable in case of multiple re-entries to the surgical site.
• Does not exert any pressure on the implant area.

FIGURE 4: ADHESIVE BRIDGE

5.) Modifying an existing prosthesis(FIGURE 5)
 Indicated when the patient seeks implant therapy to replace an existing prosthesis because it does not function properly.

• In case of existing bridges, an impression should be made with the failed bridge in place.
• It is then removed, modified and temporarily cemented back.
• In case of dentures, they can be relined and used as interims.

FIGURE 5: MODIFYING AN EXISTING PROSTHESIS

6.) Archwire supported pontic (Figure 6):
In case of an existing appliance, it can be made use of to support provisionals, which can be directly bonded over the Archwire appliance.

FIGURE 6: ARCHWIRE SUPPORTED PONTIC (USING AN EXISTING APPLIANCE)

•  Transitional implants:
• Introduced in 1993 as a treatment alternative.
• Involves the placement of miniature implants to restore fixed or removable temporary prosthesis.
• Offer a more stable, non-mobile, esthetic interim prosthesis
• Specially indicated in full mouth rehabilitations.

Prerequisites for using transitional implants:

• Bone height of at least 7mm to allow for initial stability.
• An interocclusal space of at least 6mm to 9mm.
• Transitional implants should be placed at a distance of 1mm-2mm from the site of the permanent implants to avoid interrupting osseointegration.
• In case of single tooth replacements, transitional implants should be placed lingually or palatally.

ADVANTAGES OF PROVISIONALIZATION

• Elimination of discomfort.
• The physiologic advantage of having a fixed restoration during osteointegration of the implants.
• Decreased chair time.
• Fewer unscheduled visits.
• Reduced maintenance of provisional prosthesis.
• Maintain the position of adjacent teeth.

CONCLUSION

Provisionalization means restoring esthetics, phonetics, and functional requirements from the provisional restoration while simultaneously preserving or enhancing the condition of the dental and gingival tissues until the reconstruction of the final prosthesis is completed. Therefore the primary goal of establishing a final restorative result should be no more successful than fabricating a functional esthetic provisional prosthesis that precedes it.

REFERENCES

• EL ASKARY, A.S., R.M. Meffert, and T. Griffin 1999a and b WHY DO IMPLANTS FAIL, PART 1 AND 2.
• MISCH, C.E. 1993A. PROSTHETIC OPTIONS IN IMPLANT DENTISTRY.IN: MISCH, C.E. ed. Contemporary implant dentistry. St. Louis MO: Mosby yearbook, inc, pp.43-50
• MISCH, C.E. 1993A. PROSTHODONTIC CONSIDERATIONS IN IMPLANT DENTISTRY.IN: MISCH, C.E. ed. Contemporary implant dentistry. St. Louis MO: Mosby yearbook, inc, pp. 187-200
• Nemkovsky, C., and Z. ARTZI. 2002. Comparative study of buccal dehiscence defects in immediate ,delayed and late maxillary implant placement with collagen membranes: clinical healing between placement and second stage surgery, J Periodontol, 73, pp. 753-761
• Textbook on FUNDAMENTALS OF ESTHETIS IMPLANT DENTISTRY by EL ASKARY.