Temporization is a standard procedure used to create provisional restorations that are required in the short or medium-term. Provisional restorations are frequently needed in preparation for more permanent restorations like dental implants, crowns, and bridges. Temporary restorations can be especially helpful for dental implant cases in developing the morphology of peri-implant tissues. When planning a complex case, temporization can be useful in testing and refining function and esthetics. The information yielded is then transferred to the dental lab for the creation of the final restorations. This approach can increase patient acceptance and satisfaction with their treatment.
The techniques utilized may be direct or indirect, depending on the complexity of the case, esthetic requirements, and length of time for which the provisional restoration is needed. Direct techniques usually require more chairside time compared to indirect techniques.
Ideal Properties for Provisional Restorations
Ideally, the temporization methods and materials used to create the provisional restoration should have the following properties:
- The material chosen must be dimensionally stable
- The material should be resistant to functional and occlusal loads
- The restoration must be reasonably resistant to fracture and should have sufficient compressive and flexural strength
- Restoration margins must be polished, tissue-friendly, and shaped to promote healing and discourage plaque development
- The temporization technique should ensure quick and simple fabrication
- The restoration should be esthetically pleasing
The perfect provisional restoration is biocompatible and correctly shaped to avoid tooth movement and alterations to the position of adjacent teeth and the occlusion. The restoration shape must promote good gingival healing and enhance gingival form and papillae. An excellent fit is essential for preventing microleakage, and the temporization method should be quick and efficient, making it more acceptable to the clinician as well as to the patient, who might have already undergone a lengthy procedure.
Materials Used for Temporization
Material suitable for temporization includes methacrylate resins, bisacrylate composites (bis-Acryl), or bisphenol-A-glycidyl methacrylate (bis-GMA). Each of these materials offers advantages and disadvantages. Methacrylates provide superior esthetics compared with other materials, and bis-GMA resins offer greater strength compared with bis-Acryl resins. Where flexural strength is important, bis-Acryl resins might be preferable to methacrylates. Choosing materials with fine particle sizes increases the ability to polish the cured material, improving its smoothness.
Creating Custom Fabricated Provisional Restorations
Custom fabricated restorations can be created indirectly or directly or by using a hybrid technique. A template or stent is needed to form the restoration.
If you have treatment planning casts or a diagnostic wax-up, a matrix can be fabricated in the dental lab. The matrix is prepared on the stone model or diagnostic wax-up using a stiff silicone putty. After tooth preparation, an impression is taken of the arch, and a stone model is poured. The impression can be taken in alginate or vinyl polysiloxane. Next, the silicone matrix is filled with the provisional material in the area corresponding with the prepared teeth. The matrix is placed over the stone model created using the impression of the prepared teeth. Once the material is cured, the provisional restoration is removed from the matrix and trimmed, polished, and fitted in the mouth.
Advantages of the indirect technique include:
- Reduced chairside time
- No risk of pulpal damage due to the exothermic setting of provisional materials
- The stone cast limits polymerization shrinkage
- Ability to fabricate and trim provisional restorations outside the treatment room
Potential disadvantages of the indirect technique include:
- Increased need for laboratory skills and preoperative models
- Potential for inaccuracies between models
The direct method uses either a prefabricated matrix or a custom impression matrix, which is taken before the tooth is prepared. Once the tooth preparation is complete, the matrix is filled with the temporization material. As light cannot penetrate the impression material, a self-curing resin is used to create the provisional restoration. Alternatively, clear impression material is selected for use with light-cured or dual-cured resins.
With the hybrid technique, a pre-op laboratory fabricated matrix is constructed and used for chairside fabrication of the restoration. The use of a lab-made matrix is the only difference between the hybrid technique and the direct technique.
- No additional waiting time for the fabrication of the provisional
- No need to take an impression or pour additional models, reducing the potential for inaccuracies
One disadvantage of the hybrid technique is the need for more chairside time; however, this technique can be the best when fabricating temporary veneers, which can be fabricated, finished, and polished on the prepared teeth.
Using a Matrix Button for Single Provisional Restorations
Matrix buttons are prefabricated and save chairside time, eliminating the need for another impression, and they are suitable for fabricating single provisional restorations. First, place the button in hot water until it turns clear, indicating that the material is malleable. If the tooth contours are inadequate, restore them with composite before using the matrix button. Adapt the button to the unprepared tooth and extend coverage at least 3 mm beyond the gingival margin, approximately one half of each tooth distally and mesially. Try in the matrix several times after adapting it to the tooth to ensure that the path of insertion is correctly identified.
Once the tooth is prepared, coat the inner part of the matrix with mineral oil and apply a small amount of bis-Acryl resin interproximally mesially and distally to prevent voids. Fill the rest of the matrix with the resin and insert it into the patient’s mouth. Place a roll of cotton over the matrix and ask the patient to bite down firmly until initial curing is achieved. Use a test piece of material to determine when curing begins.
Usually, the provisional restoration and the matrix will come out at the same time. Otherwise, use a plastic instrument to loosen and remove the provisional, taking care not to damage the margins. Trim, polish, and try in the provisional and then cement it in place.
Prefabricated Temporary Restorations
Prefabricated temporary restorations are available for anterior and posterior teeth and are made from composite resin, polycarbonate, and stainless steel. Polycarbonate temporary restorations are rigid and preformed. Although they can be adjusted, achieve reasonable esthetics with polycarbonate crowns is difficult. Prefabricated stainless steel crowns can be burnished for a reasonable marginal fit but are esthetically unacceptable for many patients. Prefabricated composite resin crowns are reasonably strong, providing a fracture toughness similar to custom-made provisional crowns.
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