Techniques for Fabricating Temporary Restorations: An Overview (2023)

vintage 2011 |Artikel-ID 134659 |https://doi.org/10.1155/2011/134659

ReceiveJuly 1, 2011

accepted9. August 2011

Released12. October 2011

Abstract

A properly fabricated provisional restoration is important for a successful indirect restoration. The importance of provisional restorations as an integral part of a fixed prosthetic restoration is illustrated by the abundance of literature on their importance in terms of marginal integrity, function, occlusion and esthetics. A variety of techniques are available to suit the needs and clinical situation of the individual practitioner, from a single unit to full-arch temporary fixed prostheses.

1 Introduction

The fabrication of temporary restorations is an important procedure in fixed prosthetics. Provisional restorations must meet the requirements for pulp protection, positional stability, occlusive function, cleanability, marginal accuracy, wear resistance, strength and esthetics. They have the crucial function of providing a template for the final restorations after they have been evaluated intraorally.1].

Temporary restorations in fixed prosthetic rehabilitations are important treatment procedures, especially when the restorations must function for a longer period of time or when additional therapy is required before rehabilitation is complete.2].

Provisional surgeries also need to be performed efficiently as they are performed while the patient is in the office and at the same appointment that the teeth are being prepared. Costly treatment time should not be wasted, but the dentist should produce an acceptable restoration. If you don't do this, you will end up wasting more time than originally thought.

A well-made temporary fixed partial denture is intended to provide a preview of future dentures and improve the health of the abutments and periodontium. Theories and fabrication techniques for numerous types of temporary restorations abound in the dental literature.3].

There are many methods available to fabricate satisfactory temporary restorations, involving a variety of materials. As new materials are introduced, related techniques are reported, and so there is even more variety. Common to all processes is the formation of a mold cavity as a sensible principle, into which a plastic material is poured or filled.

Temporary restorations can be placed directly on prepared teeth [4,5] using a matrix or indirectly by taking an impression of the prepared teeth [6,7🇧🇷 An indirect-direct combination [8] Also possible is the technique that has evolved as a sequential application of these and involves the fabrication of a preformed shell that is relined intraorally.

2. Search strategy

A search of the English literature on PubMed was conducted up to January 2010 using the terms: Provisional Restorations, Fixed Partial Dentures, Treatment Restorations. In addition, bibliographies of 5 previous reviews and articles published in the Journal of Prosthodontics, Journal of Prosthetic Dentistry, General Dentistry, and Journal of the American Dental Association were manually searched.

2.1. Indirect temporary fixed partial denture

The technique involves fabricating the temporary restoration outside of the mouth. The fabrication of temporary restorations using the indirect technique eliminates the problems of the direct technique and also has the advantage that it can be partially delegated to auxiliary personnel [6🇧🇷 Fischer et al. describes the use of an indirect technique to fabricate temporary restorations using quick plaster. The technique has several advantages over direct methods. There is no contact of the free monomer with the prepared teeth or gingiva to cause tissue damage and allergic reactions or sensitization. The technique avoids exposing the prepared tooth to the heat generated by the polymerizing resin. The indirect technique results in a restoration with excellent marginal fit and relieves the patient and dentist for a significant period of time, as an assistant is involved in fabricating the restoration in the laboratory.1,9].

Compared to the direct technique, it has fewer disadvantages. The main disadvantage of the technique is an increased chair side time and an increased number of intermediate steps. It is a tedious task to perform when there are insufficient lab assistants or facilities. In addition, the technique involves the use of and possible damage to diagnostic models [10].

Procedure:
(1)Place a selected acrylic tooth in the area of ​​the missing tooth on the diagnostic model and seal with the carding wax.(2)Then, in addition to the abutment teeth, a silicone mass index is performed, involving at least one tooth at a time.(3)Prepare the patient's teeth as usual.(4)Take a section impression of the prepared teeth and adjacent structures and cast a control mold.(5)Lubricate the control model with petroleum jelly or other suitable release agent, mix and place the provisional restorative material on the surface of the index mesh and seat it on the control model.(6)Try the preformed restoration in place in plaster and intraorally.(7)Fill the provisional restoration to improve the internal fit.(8)Finish, polish and cement the restoration (Fig1).

2.2. Indirect-Direct Temporary Fixed Partial Denture

The technique creates a custom preformed outer surface shape of the restoration, but the inner surface shape of the tissue is formed by poorly prepared diagnostic models. This indirect-direct method has several advantages. With the combined indirect-direct technique, the treatment time can be reduced because the temporary shell is made before consulting the patient. The improved control over the contours of the restoration minimizes the time required for lateral chair adjustments. In addition, less acrylic resin polymerizes in contact with the prepared abutment, resulting in less heat build-up, less chemical exposure, and less polymerization contraction compared to the direct technique [1🇧🇷 Another advantage is that the contact between the resin monomer and the soft tissues is reduced and there is less chance of allergic reactions.

The disadvantage of this procedure is the potential need for a laboratory phase prior to tooth preparation and the adjustments often required to fully seat the shell on the prepared tooth.

Procedure:
(1)Cast an accurate diagnostic model from an impression of unprepared teeth prior to treatment. For FPDs, wax a pontic on the edentulous area of ​​the study cast and modify with wax for optimal contours, contacts and occlusion.(2)Lightly oil the modified diagnostic model and take an impression with a high-viscosity elastomeric impression material. To provide sufficient volume of material at the edges of the provisional, use a round bur to trim the sharp edge of the elastomeric overprint representing the gingival sulcus to allow for additional volume of resin material in this area. The silicone mass index is performed on at least one tooth in addition to the abutment teeth.(3)Remove the acrylic tooth and prepare the abutments on the assembled diagnostic models. (Diagnostic plaster preparations should be more conservative than any tooth preparations and closely follow the gingival margins.)(4)Lubricate the prepared diagnostic model with petroleum jelly or a suitable separating medium, mix the temporary restorative material and place it on the surface of the index tissue and replace it on the prepared diagnostic models.(5)Finish the restoration after the acrylic resin has polymerized. The provisional must be wafer-thin and correctly contoured and follow the gingival margins exactly in the impression.(6)Prepare the patient's teeth as usual (up to the gum line).(7)Try it on the preformed restoration. (If tooth reduction is sufficient, the provisional restoration will have an ideal marginal fit with no adjustment required.)(8)Fill the provisional restoration to improve the internal fit.(9)Finish, polish and cement the restoration (Fig2) [6,8].

2.3. Direct temporary fixed partial denture

In the direct technique, the patient's prepared teeth and gum tissue directly provide the shape of the tissue surface, eliminating any intermediate laboratory procedures. This is useful when the training of assistants and office laboratory facilities are insufficient for the efficient fabrication of an indirect restoration. However, the direct technique has significant disadvantages, such as B. potential tissue injury from the polymerizing resin and an inherently poorer edge fit. Therefore, routine use of directly molded provisional restorations is not recommended when indirect techniques are possible.

Procedure:
(1)Before tooth preparation, place a plastic tooth in place of the missing tooth and take an alginate impression or mass index.(2)Prepare the patient's teeth as usual.(3)Lubricate the prepared teeth and adjacent gingival margins with petroleum jelly and replace the index or alginate impression with putty-stage temporary restorative material on the tissue surface of the impression.(4)Remove and replace the restoration until it has cured.(5)Finish, polish and cement the restoration (Fig3).

2.4. Alternative techniques to the direct technique

(1) Acrylic resin block technique for direct provisional restoration
A useful, albeit seldom used, method for fabricating temporary restorations is the acrylic resin block technique. It offers the possibility to fabricate the provisional restoration without the use of diagnostic models and laboratory processing costs. The technique requires knowledge of tooth anatomy and the patience and artistic qualities inherent in dentists.Procedure:
(EU)Tooth preparation is done in the usual way.(ii)The self-curing acrylic resin of the appropriate color is mixed and allowed to cure to a paste-like consistency (the surface monomer gloss has completely disappeared). After lightly lubricating the abutments and surrounding gingiva with petroleum jelly, the acrylic resin registration is placed over the prepared abutments and the patient is guided to the closure in centric occlusion.(iii)The acrylic disk is removed and replaced a number of times during the polymerization process to minimize the effect of exothermic heat on the abutments. After curing, the occlusal surface of the resin registration is analyzed for anatomical design and can be marked in pencil for cusp position and buccolingual width to aid in carving crown molds.(4)The contour and shape of the temporary restoration are roughly developed with carbide burs and diamond stones.(v)Since no impression matrix is ​​used to transfer the acrylic resin mixture over the prepared teeth, the base plate must be relined to ensure proper marginal fit and integrity. The interior of the crowns is lightened with a carbide round bur to create space for the relining resin. The inner surfaces are wetted with monomer and filled with a new acrylic resin mixture. The splint is then placed back onto the prepared abutments while the acrylic resin cures. The patient is oriented again in the centric occlusal position for closure.(vi)The provisional restoration is modeled to correct the occlusal anatomy, the crown contour and the shape of the edentulous space with burs, stones and discs. This must be done with great care and attention to detail to approximate the environment that the final restoration aims to create. The provisional splint should be smooth and highly polished.(vii)The completed provisional restoration is now ready to be seated with provisional cement. Zinc oxide and eugenol cements should be avoided as they tend to soften the acrylic on contact and weaken the restoration.3].

(2) Before beginning the preparation of the crown, an irreversible hydrocolloid impression is taken and immediately poured while the anesthetic acts. Then a plastic tooth is placed on the diagnostic model in the area of ​​the missing tooth and a shell matrix with mouthguard material is individually made. Lubricate the prepared tooth and adjacent teeth. Add enough tooth-colored acrylic resin to just fill the prepared tooth gap in the tray matrix and place the matrix over the teeth in the patient's mouth, pressing against adjacent teeth. Wait until the material has hardened, finish, polish and cement the restoration.

Alternatively, the restoration can also be made outside of the patient's mouth in the master impression after the tooth preparation with the individually manufactured shell matrix and is therefore an indirect procedure [11].

(3) After the contours of severely fractured teeth are restored with wax, a preliminary alginate impression is taken with a standard toothed spoon in the area to be prepared. Preferably a full sheet impression is obtained. Margins and septa are cut from the defined impression to facilitate re-insertion into the mouth. When a posterior fixed partial denture is fabricated, a strip of irreversible hydrocolloid is removed from the edentulous ridge area to form a pontic on the finished temporary restoration. If an anterior fixed partial denture is being made, a denture tooth (or teeth) can be held in place with a small piece of soft wax before the impression is taken.

Instead of replacing the lost tooth in the provisional restoration in the posterior quadrants, another technique allows the alginate impression to be marked in the form of a bar that crosses the edentulous area and connects the abutment teeth, creating a final restoration with crowns on the abutment teeth . . . connected by a bar that maintains the integrity of the restoration. Instead of marking a slash, a reverse pontic can be marked on the alginate impression.

(4) With this technique, after removing the tray from the mouth, trim the proximal overhangs of the impression material and trim off the excess palatal/lingual and buccal/facial impression material to ensure complete realignment of the intraoral tray. Therefore, 1mm grooves should be created on this preoperative impression buccally and lingually to the margin of the prepared tooth and continuing towards the buccal and lingual areas of the flange to provide a pathway for excess temporary restorative material [12].

(5) In another technique, a temporary removable partial denture, which is often used to replace anterior teeth prior to fixed prosthetic treatment, is used as an aid in the fabrication of a temporary fixed restoration.

An irreversible hydrocolloid impression of the anterior segment of the temporary removable partial denture is taken. Cold-hardening acrylic resin in the appropriate color is poured onto the print or applied using the powder-liquid method. The hardened plastic is taken from the impression as a block section of the front teeth and stored in water until use. When the provisional fixed splint is fabricated, this section of the bridge block is attached directly to the provisional crowns for the abutment teeth. The pontic locking part can also be helpful if you lose the removable temporary restoration. Abutment teeth can then be prepared, individual provisional abutment crowns made and the pontic attached. Alternatively, unprepared abutment teeth can be acid etched and the acrylic pontic block section bonded directly to it with composite resin.

Alternatively, an indirect impression can be taken with the existing removable partial denture and this impression can be used to fabricate the provisional restoration by placing it on the master cast that would be fabricated after tooth preparation.

(6) With either of these techniques, instead of building up the entire tooth with self-curing resin, the acrylic tooth can be trimmed to form a labial veneer and the rest of the tooth built up with self-curing resin. This tooth trimmed in the form of a veneer can be used directly in the patient's mouth and the rest of the tooth constructed or used indirectly in a mold.

(7) Using the existing prosthesis as a temporary restoration: When a cemented fixed prosthesis has to be removed for remaking, damage to the prosthesis is of little concern. The important principle in this case is to remove the prosthesis with minimal risk to the natural abutment teeth. It is possible to remove a cemented fixed prosthesis with little or no risk of damaging the abutment teeth by dissecting the prosthesis and expanding the retainer. Once removed, the prosthesis can be reconstructed to be used as a temporary or provisional prosthesis. The advantages of using the existing prosthesis are that the long fixed partial with metal reinforcement is stronger; the prosthesis suffers less occlusal wear with a metal or porcelain restoration than with an acrylic restoration; Less time required to fabricate a temporary restoration [13].

Alternatively, an impression of the existing fixed partial denture can be taken before attempting to remove it, and this impression can be used to fabricate the temporary restoration by placing it over the master impression that would be made after tooth preparation.(8)If the patient presents an already finished tooth preparation and without a provisional, the following measures can be taken.(one)Build up the prepared tooth with the carding wax and place a plastic tooth in the area of ​​the missing tooth, take an impression and use it to make the temporary.(b)Take the impression of the prepared tooth as is and then mark the impression in the inverted pontic mold and also in the area of ​​the prepared tooth to try to duplicate the unprepared tooth.(c)Use the acrylic resin block technique to form a direct provisional restoration.(9)Temporary restoration for pins and core build-ups:(EU)If custom posts and cores are used, the post and core portion can be designed immediately and a temporary crown fabricated over it.(ii)If a cast post is required for the final restoration, the following actions can be taken.(one)A ball post can be placed in the post gap and an alginate overimpression made to capture the ball post and then the restoration fabricated in the impression.(b)Instead of placing the ball post directly into the post gap, it can be placed in the impression and the restoration fabricated.(c)As an alternative technique, a ball post can be placed in the post space and the restoration fabricated intraorally using the acrylic resin block technique. A tooth trimmed in the form of a labial veneer can also serve this purpose.