November 1, 2014
by Suzanne Caudry, PhD, DDS, MSc (Perio)
Advances in technology have created a society that has come to expect immediacy in all things including dentistry. This, combined with an ongoing aesthetic focus, is what has forced dentistry to continue refining the field of implantology, and propelling clinicians toward more immediate options. In 2003, Kan et al.1 published favourable results of a one-year prospective study evaluating implant success rates, peri-implant tissue response and aesthetic outcomes of immediately placed and provisionalized maxillary anterior single implants. These implants were followed for two to eight years after, and results showed a one hundred percent implant survival rate.2
Immediate implant placement has been identified as a reliable technique permitting a reduction in treatment time for prosthetic rehabilitation; however, there are multiple factors that can compromise the success of immediate implantation.3 There is still debate and need for more long-term studies on the functional and aesthetic outcomes of immediately placed implants.4
After the challenge of appropriate implant placement within both biological and prosthetic constraints, the next challenge is the development of the emergence profile for optimization of soft tissue aesthetics. One must consider the question of why to temporize? Often it is presented primarily (especially to the patient) as a short-term aesthetic solution. But the importance of a well-designed temporary in creating an aesthetic final restoration with healthy soft tissues cannot be overstated. Both placement and temporization can affect the aesthetic and functional outcome and ultimately the patient’s long-term satisfaction.1,5,6 This article reviews the available current solutions for temporizing immediate implants in the anterior maxilla and presents an aesthetic solution for temporization which will serve as the foundation for long-term success. This article also reviews a simplified approach to cementation of the final restoration.
It is always prudent planning to have a removable appliance available at the time of surgery in the event that immediate temporization is not possible (e.g. lack of implant primary stability). There are two options for removable appliances after implant placement: an acrylic removable partial denture (RPD) or an Essix appliance (Fig.1). Neither of these solutions contributes to long-term success but rather ‘fills a void’ and provides moderate aesthetics. The advantage of a well-adjusted Essix retainer is that there is no pressure or occlusal forces transmitted to the newly placed implant or the soft tissues. The dental laboratory will fill the edentulous space in the appliance with tooth coloured acrylic or a denture tooth to provide a somewhat aesthetic appearance. If the patient’s tooth can be preserved during extraction it can be used within the appliance to provide a more natural appearance.
FIGURE 1A. & 1B. Essix retainer as temporization for the immediate implant with a healing abutment at site 21.
The pros and cons of all forms of temporization must be thoroughly reviewed with the patient prior to surgery, including the fact that a removable appliance may be the only option available. Many patients cannot or will not tolerate a removable appliance for even a short period of time due to aesthetics and/or limited function. The alternative is a temporary resin-bonded bridge, which may or may not be possible due to the patient’s tooth alignment, occlusion, existing adjacent restorations or may be problematic because of de-bonding.
TEMPORARY ABUTMENTS FOR IMMEDIATE TEMPORIZATION
If various criteria are met and it is deemed appropriate to use a temporary abutment, such an abutment should be ideally inserted within 24 hours of implant placement to avoid any possibility of disturbing the implant’s primary stability achieved during surgery.7
Historically, cement-retained prostheses were used for single-unit reconstructions, while screw-retention was used for full-arch fixed reconstructions.8 However screw-retention (for temporary and final single-unit prostheses) offers important benefits over cement-retention, such as easy retrievability and no concerns regarding excess cement remaining in the peri-implant tissues. Unfortunately, temporary screw-retained restorations are not always an aesthetic choice in the anterior given the anatomy of the pre-maxilla and the possibility of the composite-filled abutment screw access hole through the buccal surface or the incisal edge of the temporary crown. This is especially a problem with the incisal edge because of the chair-side difficulties in replicating natural translucencies.
As a result, conventional immediate implant placement in the anterior is through the cingulum position of the original tooth. This allows the use of an aesthetically pleasing screw-retained temporary abutment because the abutment screw access hole is not visible when the patient smiles. However, if the implant is placed too palatal the final prosthetic restoration may have excessive buccal cantilever, which may lead to negative soft tissue consequences disrupting the natural gingival architecture.
To avoid excessive palatal placement given the angulations and buccal concavities of the pre-maxilla, the implant is usually placed along the long axis or slightly buccal to the long axis of the original tooth. For aesthetic reasons these placements would necessitate a cement-retained temporary, which is not currently the preferred method for temporization; temporary abutments directly from the manufacturer typically place the crown margin too close to the implant prosthetic platform and therefore too deep for cement removal. It is very difficult, if not impossible, to remove any over-flow cement that may extrude into the surgical site. Many implant companies now provide resin temporary abutments for chair-side fabrication and delivery; however, this is time consuming and complicated for the restorative dentist and may be problematic because of fracture, de-bonding or soft tissue trauma.
The solution: With directions from the restorative dentist, the dental laboratory fabricates a highly polished two-piece cement-retained custom abutment and custom crown (Figs. 2, 3 & 4). They fabricate the abutment such that the cement line will be at or slightly below the gingival level to facilitate removal of excess cement (Fig. 5). When possible, a putty replica of the extracted tooth should be provided to the laboratory so that they can more accurately customize the size, shape and contour of the abutment to enhance the development of the desired emergence profile as the soft tissue heals. If this is not provided the laboratory has no information about the original emergence profile between the CEJ and crest of bone often necessitating chair-side adjustments. This is not only time consuming but will result in the removal of the highly polished surface of the abutment. A highly polished surface is ideal for soft tissue healing and whenever possible should not be marred.
FIGURE 2A. & 2B. Presentation of the non-restorable tooth 1
1 prior to extraction.
FIGURE 3A. & 3B. Laboratory fabricated custom metal/resin (opaqued) temporary abutment and crown for the immediate implant placed at site 11 following the extraction of the non-restorable tooth 11.
The temporary abutment is inserted, verified for contour, seating and hand tightened (Fig. 4). The screw access is blocked (e.g. teflon) for easy retrievability and then the crown is cemented with temporary cement (excess cement removed) and carefully adjusted. If the dental laboratory receives accurate information, including a putty replica for the extracted tooth, this should be a short appointment for the patient with few try-ins and adjustments thus minimizing soft tissue trauma. To avoid concerns regarding possible fracture of the cement-retained crown during removal, ask the laboratory to prepare an extra temporary crown to have on hand as a precaution.
FIGURE 4. Radiograph of the temporary abutment verifying correct seating prior to cementation of the temporary crown.
Retrieval of the crown and temporary abutment should be straightforward when the time comes for the final restoration. The advantage of a temporary custom abutment, versus placing a final abutment at the time of immediate implant placement, is soft tissue healing and establishment of the emergence profile prior to the final impression. This confers a more accurate translation of the gingival contours and margins to the final abutment and crown. The result – the zenith height of the final implant supported restoration is at the same height as the original tooth and the soft tissues have a natural appearance (Figs. 2 & 6).
FIGURE 5 A & 5B. One-week PO of the immediate implant with immediate temporization. Note the cement line is slightly below the gingival margin.
FIGURE 6. 18-month follow-up of the final restoration.
ADDITIONAL LABORATORY AIDS:
1. Impression for fabrication of the temporary abutment and crown
Avoiding contamination of the surgical site is critical. A laboratory pre-fabricated impression stent, with a light cured material to lute the impression coping into place, eliminates the use of conventional impression material but still communicates implant position to the laboratory (Fig. 7). Once the impression is taken a healing abutment is placed while the laboratory fabricates the custom temporary abutment and crown (Fig. 8).
FIGURE 7. Laboratory pre-fabricated impression stent with the luted impression coping.
FIGURE 8. Healing abutment is placed while the laboratory is fabricating the temporary custom abutment and crown.
2. Final restoration – controlled cement overflow
A significant implant complication is cement extrusion into the peri-implant tissues at the time of cementation. Unlike natural teeth, dental implants do not have a sulcus to expel any overflow cement left behind during cementation of the restoration; any excess cement will remain in the peri-implant tissues resulting in inflammation and bone loss. Excess cement has been linked to peri-implantitis9 and crestal bone loss.10
A simple method to avoid cement over-flow for permanent cementation is described by Caudry et al. (2009).11 The dental laboratory fabricates a final abutment putty analog. This analog will mimic the internal shape of the final crown and is inserted into the crown to extrude excess cement prior to delivery (Figs. 9 & 10). What remains is the precise amount of cement needed (Fig. 11). Retention for an implant crown should come primarily from the design of the abutment and the crown, not the cement.
FIGURE 9. Putty analog of a final abutment.
FIGURE 10. Cement is added to the final crown and extruded by inserting the putty analog.
FIGURE 11. Final crown with the correct amount of cement is now ready for delivery.
With the advancement of immediate implantology the profession needs to consider the purpose of immediate temporization. Rather than merely ‘filling a void’, a well-designed temporary can be a critical component in the long-term aesthetics and success of immediate implants. Until recently the accepted, usual position for an immediate implant with immediate temporization in the anterior maxilla has been through the cingulum to allow for the use of a screw-retained temporary which avoids cement overflow issues and permits easy retrievability. However, this palatal placement can compromise the final aesthetic outcome. If the implant is placed along the long axis of the original tooth or slightly buccal to this position it can lead to challenges with temporization. With careful planning and direction to the dental laboratory they can fabricate a custom, two-piece cement-retained temporary abutment and crown. This provides the opportunity for optimal aesthetics and function in the temporary and final restorations while minimizing chair-side time and complications. OH
Many thanks to Drs. Monica Raina, Jack Slome and Nick Kemp, as well as to Mary-Anne Giancola, Dental Services Group (custom temporary abutment and crown) and Gordana Dental Art Studio (putty analog).
Dr. Suzanne Caudry, PhD, DDS, MSc (Perio) maintains a private practice in downtown Toronto. She teaches implant surgery, bone reconstruction and cosmetic periodontal surgery to the graduate periodontal students at the University of Toronto. She also provides study clubs and mentorship programs for her referring dentists, is a frequent guest lecturer at national and international meetings and is actively involved in dental research. Dr. Caudry may be reached at (416) 928 3444, firstname.lastname@example.org, Linked-In, or through her web site at www.drcaudry.ca/
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2. Kan J, Rungcharassaeng K, Lozada J, Zimmerman G. Facial Gingival Tissue Stability Following Immediate Placement and Provisionalization of Maxillary Anterior Single Implants: A 2- to 8-Year Follow-up. Int J Oral Maxillofac Implants 2011; 26: 179–187.
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8. Sailer I, Muhlemann S, Zwahlen M, Hammerle C, Schneider D. Cemented And Screw-Retained Implant Reconstructions: A Systematic Review Of The Survival And Complication Rates. Clin Oral Implants Res 2012; 23 (Suppl. 6): 163–201.
9. Wilson Jr TG. The Positive Relationship Between Excess Cement and Peri-Implant Disease: A Prospective Clinical Endoscopic Study. J Periodontol 2009; 80: 1388-1392.
10. Shapoff CA, Lahey BJ. Crestal Bone Loss and the Consequences of Retained Excess Cement Around Dental Implants. Compendium of Continuing Education in Dentistry 2012; 33(2): 94-6, 98-101.
11. Caudry S, Chvartszaid D, Kemp N. A Simple Cementation Method To Prevent Material Extrusion Into The Peri-implant Tissues. J Prosthet Dent 2009; 102: 130-131.
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