Fixed and Removable Provisional Options for patients undergoing Implant treatment
Sang-Choon Cho, DDS, Clinical Assistant Professor; Saphal Shetty, MDS, Resident; Stuart Froum, DDS, Clinical Professor; Nicolas Elian, DDS; Clinical Professor; Dennis Tarnow, DDS, Professor and Chair; Department of Periodontology and Implant Dentistry, College of Dentistry, New York University, New York, New York.
Abstract
The provisional phase of treatment can be the most challenging aspect of implant dentistry. The techniques available today include removable, tooth-supported, andimplant-reatined provisional restorations. The selection of the type of provisional prosthesis should be based on esthetic demands, functional requirements, duration, and ease of fabrication. This article includes a review of 118 articles from peer-reviewed journals published in English from January 1986 lo February 2007. This review was performed using MEDLINE. The indications, advantages, and disadvan­tages of the various provisional restorations are discussed.
Learning Objectives
After reading this article, the reader should be able to:

• Discuss the advantages and disadvantages of various provisional restorations used during implant restorative treatment
• Explain the recommended uses of removable and fixed provisional restorations for patients undergoing implant therapy
• Describe the currently used provisional restorations, their indications, and contraindications for a patient receiving implants

Implant restorations have been docu­mented to be a predictable prosthetic treatment with high success rates for restoring patients who are partially and completely edentulous.1 Branemark and colleagues recommended a 4- to 6-month period of undisturbed healing with a 2 stage surgical protocol.2 However, during this healing period the patient requires aprovisional restora­tion for function, phonetics, and esthetics. The latter is especially critical in the anterior pan of the mouth (Figure 1). Ideally, the provisional should also help the patient adapt to the form of the final restoration while protecting the surgical side, by avoiding transmucosal loading.
Several techniques are used today to provisionalize a patient receiving implants. These include removable prostheses ("flipper," Essix provisional! or fixed partial dentures (resin bonded bridge, fixed prosthetics with or without the use of transitional implants). These approaches have been described in the literature.3-8
However, if support for the removable provisional prosthesis is being pro­vided by the underlying soft tissue, undesired pressure may be applied 10 the healing surgical site. This may be detrimental In final implant survival if pressure is transmitted to the healing implants, regardless of whether they were placed with a 1 or 2 stage protocol. Moreover, a removable provisional is not readily accepted by most patients because of its nature. Provisionals using fixed partial dentures (FPDs) may be preferred by many patients because they eliminate transmucosal loading and are not removable. However, the adjacent must be prepared for partial or full coverage to support the fixed provisional restoration To address the requirement for undisturbed healing and fixed provisional, transitional narrow diameter implant-supported provisionals have been used. These implant-supported FPDs provide uninterrupted healing of the implant site and/or grafted ridge, and restore function and esthetics during the time the patient is required to wear the provisional.
The purpose of this literature review is to discuss the as provisional restorations currently used during implant therapy and review their indications, contraindications, advantages, and disadvantages.
Materials and Methods
This paper includes a review of  118 articles from peer-reviewed journals published in English from January 1986 to February 2007 The review was performed using MEDLINE. The keywords used were "implant provisionalization" (57 articles), "fixed provisionalization" (19 articles), "transitional implants" (2 articles), and "removable inter­im prosthesis for implants'' (40 artiles).
Interim Removable Partial Denture
An interim removable partial denture (RPD) is often used as a provisional restoration during the construction of an implant-supported prosthesis (Figure 2). Simplicity of fabrication, cost, and ease of insertion are the most obvi­ous advantages of his provisional restoration.  An addi­tional advantage is the ability to modify an acrylic resin interim RPD to accommodate any changes in the ridge anatomy for patients who may require multiple procedures of extraction, soft- and hand-tissue augmentation, and implant placement.
The use of an RPD has been less popular when treat­ing partially edentulous patients because these provision­al restorations are bulky, interfere with speech, and may initiate an inflammatory soft-tissue response. Patients with strong gag reflexes are often unable to wear remov­able prostheses that partially cover the palate. During the initial periods of integration or after soft- and hard-tissue augmentation, removable prostheses should remain pas­sive over the implant site. Accomplishing this may neces­sitate an unsightly gap between the ridge and neck of the demure teeth (Figure 3).
Another disadvantage of interim RPDs is their inabil­ity to facilitate soft-tissue contouring, except as described in a case report where ovate pontics were used with RPDs to accomplish this.9 In that report, a denture tooth of the appropriate mold and shade was selected and retrofitted onto the ovate concavity using acrylic resin that was pre­pared on  the cast .  The  RPD was inserted immediately after the extraction of the tooth and immediate implant placement. The RPD was adjusted such that it did not contact the healing abutment and also provided immedi­ate support and maintenance of soft-tissue architecture. However, the use of ovate pontics is usually associated with provisional FPDs because they are tooth supported and provide stability during soft-tissue remodeling.
Essix Provisional

The Essix provisional is matte either in the laborato­ry or in the dental office from clear thermoplastic sheets to retain pontics for missing teeth (Figure 4). The pontic is fabricated by applying the vacuum form sheet under high pressure and heat over the denture teeth.4 The technique is relatively quick and inexpensive and is therefore convenient to fabricate. Pressure on the surgical sites is easily avoided because the Essix provisional is tooth retained. This prosthesis replaces the missing teeth and avoids transmucosal loading of the healing site after tooth extraction, site development, or implant surgery.
However, Essix provisional may not be appropriate as long-term provisional restorations because they are esthetically unacceptable to the patient. Moreover, they derive their support by covering the adjacent teeth in the arch and make chewing difficult. In addition, occlusal wear may limit their durability.

Fixed Provisional Prosthesis
Fixed provisional prostheses include bonded extract­ed natural teeth, demure teeth, and cast metal reinforced resin bonded fixed partial dentures. Denture teeth or extracted natural teeth may be bonded to the adjacent etched tooth surfaces and are usually indicated for short-term use. Esthetic results in some cases may be unacceptable because of the bulk of the composite resin in the prox­imal spaces needed to retain the pontic {Figure 5). A resin bonded fixed partial denture (RBFPD) is retained and sup-parted by adjacent teeth, and thus remains passive over the surgical site (Figure 6).
Cast metal reinforced RBFPDs were originally devel­oped as a conservative option for definitive tooth replace­ment, but are frequently used as provisional prostheses for implant patients.5 However, optimal esthetics may be a problem with this prosthesis because thin or translucent teeth are often unable to mask the gray color of the palatal metal retainers. In addition RBFPDs are relatively expen­sive for a short-term prosthesis and may require prepara­tion of adjacent teeth. Moreover, the retention of the pros­thesis is unpredictable because it may debond frequently.
In cases where teeth adjacent to surgical sites require complete coverage restorations, FPDs offer a convenient and predictable option without compromising the implant site. Perel also discussed an alteration in the sequence of treatment by retaining periodontally involved hopeless teeth to support a provisional HPD during the healing phases, which can then be convened in an implant retained prosthesis by relining it intraorally using autopolymerizing resin, without the use of a removable transition­al prosthesis (serial extraction)10-11. Provisional restorations can present a challenge because they often must be used fur an extended period of time. Hence, different techniques for strengthening provisional restorations by adding metal reinforcing structures have been described (Figure 7).12-13 These prostheses, like other tooth-borne provisional restorations, can function without pressure on the gingival tissues. Minimal effort is required to remove the acrylic prosthesis when alterations are necessary, and these FPDs also help contour the soft tissues. Unfortunately, they may fracture or loosen, causing root sensitivity or resulting in recurrent caries.
Transitional Implants
The healing phase is hard- and soft-tissue augmen­tation procedures requires that no pressure be placed on the grafted and/or regenerated ridge tissues or the implants themselves. To address this problem, several authors have presented a technique to avoid any transmucosal loading by using immediately loaded transition­al implants (TIs) to support fixed provisional restora­tions.6-8 These implants permit the patient to use a provi­sional fixed restoration with form and function similar to those of the definitive prosthesis. Provisional prostheses supported by TIs have high acceptability and are com­pletely implant supported (Figure 8).
Transitional implants can be placed in the potential implant sites before the ridge augmentation procedures or adjacent to the sites of the definitive implants. These implants are immediately loaded after a chairside reline of the interim removable partial dentures or polycarbon­ate crowns using autopolymerizing resin. Research in both animals and humans has demonstrated that early loading may lead to successful integration and at the same time increase the quantity of bone in direct contact with the implant surface. Increased areas of bone within threads as well as around the apices of immediately loaded implants also has been reported.14-15 Use of TIs allows uninterrupted healing at the implant and/or graft­ed site, eliminates the need for removable prostheses, and also allows soft-tissue contouring fur better final out­come (Figures 9 and 10).
Although these implants have been used with great success, excessive loading on TIs may result in their frac­ture. Moreover, placement of TIs too close to the defini­tive fixtures may prevent complete integration of the implant and the surrounding hard tissues.16
Conclusions
The provisional phase of treatment can be the most challenging aspect of implant dentistry. The techniques available today include removable, tooth-supported, and implant-retained provisional restorations. The selection of the type of provisional prosthesis should be based on esthetic demands, functional requirements, financial con­siderations, duration required, and ease of fabrication. Distinct advantages and disadvantages (Table 1) of each approach should be evaluated in light of the specific needs of each patient (Table 2). The results of this review concluded that:

• Tooth-supported and TI-supported fixed prostheses showed better patient acceptance, function, esthet­ics, phonetics, support, comfort, and soft tissue con­touring than removable provisional prostheses.
• The use of TI-supported provisional prostheses may be a more conservative approach than tooth-support­ed FPDs with the advantage of not having to prepare the adjacent teeth
• The type of provisional should be determined by a consideration of the advantages and disadvantages of each approach, the local conditions present at the edentulous site, the prosthetic requirements of the teeth adjacent to the edentulous site, and the pa­tient's desires, and requirements.

Figures
Figure 1     Edentulous space in the esthetic zone
Figure 2     Tissue-bone provisional removable partial denture
Figure 3     Relieved pontics after ridge augmentation
Figure 4     Essix provisional supported by coverage over the adjacent teeth
Figure 5     Resin bonded provisional. Compromised esthetic result because of bulk of composite resin and tooth size discrepancy
Figure 6     Resin bonded fixed partial denture
Figure 7     Metal reinforced provisional restoration using adjacent teeth
Figure 8     Conversion of a removable prosthesis to a transitional implant supported prosthesis
Figure 9     Fixed transitional implant supported provisional postoperative soft-tissue contouring
Figure 10   Transitional implant supported fixed provisional restoration.
References
Adell R. Lekholm L. Rockier B. et al   A   15 year study of osseointegrated implants in the treatment of the edentulous )>w. Int J Oral Surg,. 1981:10:387-416.
Branemark PI. Osseointegration and its experimental background. J Prosthet Dent. 1983;50:399-410.
Markus SJ. Interim esthetic restoration in conjunction with interior implants.  J Prosthet  Dent. 1999;82:233-236.
Moskowitz EM. Sheridan JJ, Celenza F Jr, et al   Essix appliances. Provisional anterior prosthetics for pre and post implant patients NYState Dent J  1997:63 32-35
Zinner ID, Panno FV, Pines MS. Et al. First-stage fixed provi­sional restorations for implant prosthodontics.  J Prosthodont 1993;2:228-232.
Froum SJ. Emtiaz; S. Bloom MJ. et al. The use of transitional implants for immediate fixed temporary prostheses in cases of implant restorations. Pract Periodontics Asthet Dent   1998;10:737-746
Petrungaro PS, Smilanich MD. Use of modular transitional implants in the partially edentulous patient. Contemporary Esthetics and Restorative Practice  1999;3:50-62

Petrugano PS. Windmiller N. Using transitional implants during the healing phase of implant reconstruction. Gen Dent 2001;49:46-51

Kan JY. Rungcharassaeng K, Kois JC Removable ovate pontic. for peri-implant architecture preservation during immediate Implant placement. Pract Proced. Aesthet Dent 2001;13:711-715
Perel ML   Progressive prosthetic transference for root form implants Implant Dent 1994;3:441-446
Balshi TJ Converting patients with periodontally hopeless teeth to osseointegration prostheses Int J periodontics Dent 1988;8:8-33
Amsterdam M, Fox L. Provisional splinting-—principles and techniques. Dent Clin North AM 1959;3:73-99
Emtiaz  S,  Tarnow  DP   Processed  acrylic  resin  provisional restoration with lingual cast metal framework. J Prosthet Dent 1998;79:484-488
Piattelli A Corigliano M, Scarano A, et al. Immediate loading of titanium plasma-sprayed implants an histologic analysis in monkeys. J Periodontol 1998;69:321-327
Romanos GE, Toh CG. Siar CH. et al. Bone-implant interface around titanium implants under different loading conditions: a histomorphometrical analysis in the macaca fascicularis monkey. J. Periodontol 2OO3:74: 1483-1490
Petrungaro PS. Fixed temporization and bone augmented ridge stabilization with transitional   implants    Pract  Periondontics Asthet Dent  1997,9 1071-1078.