Dental implants have become widely accepted for the replacement of missing teeth due to their high success rates. Conventional multistage approaches to implant reconstruction have contributed to professional’s acceptance of implant dentistry as a treatment option, perhaps the treatment of choice. New innovation procedures often enable clinicians to achieve function and aesthetics in shorter treatment periods. Following is a description of one such technique demonstrating surgical and restorative ideas that provide soft tissue integration and long-term implant success.
Endosseous implant-supported restorations delivered in accordance with the traditional Brnemark protocol have proven to be highly predictable.1 As described this protocol requires a twelve month healing period following tooth extraction, with an additional undisturbed healing period of six months following implant placement. Both were long considered to be a prerequisite for the osseointegration of dental implants in the maxilla.
The application of these time intervals to treatment plans for maxillary anterior cases presents patient with aesthetic and functional limitations as well as emotional considerations. At the same time, clinicians must contend with the effects of resorption of the alveolar process.2-4 In order to shorten the overall duration of treatment and preserve both soft and hard tissues, newer protocols have focused on reducing or even elimination the time that elapses between tooth extraction and implant placement and between implant placement and prosthetic restoration delivery. There are many variables that must be considered when selecting patients for immediate placement or loading procedures.
Placing implants into fresh anterior extraction sockets in the maxilla prevents bone resorption, which normally occurs after tooth extraction and often prohibits the surgeon from placing implants in an optimal position. Proper maintenance of the crestal anatomy tens to maintain those parameters that are recognized as essential for aesthetic treatment. While ideal positioning may involve the creation of a gap between the socket and the implant, immediate implantation has been shown to have a favorable outcome even without the use of barrier membranes or other regenerative materials as long as the bone to implant gap does not exceed the 1.5mm ‘jumping distance’.4-7
CASE PRESENTATION
A 39-year-old female hygienist presented with a horizontally fractured tooth #12. The patient was asking that it be replaced with an endosseous implant, with emphasis placed upon maintaining the natural esthetics of the soft tissues and maximizing the aesthetic potential of the proposed restorative phase (Fig. 1).
The patient’s medical history was noncontributory. Tooth #12 was no restorable due to a sub-crestal horizontal root fracture. No clinical evidence of bruxism or clenching was detected. A clinical evaluation including periodontal screening was also conducted. The patient presented with a thick-flat periodontal biotype, and no signs of periodontitis were evident. Intraoral radiographs were taken to evaluate the surrounding alveolar bone, the position of the fracture and the interdental height of bone.
The treatment plan called for atraumatic extraction of the residual root #12, immediate replacement with an endosseous implant which was immediately loaded in a rather unique fashion.
SURGICAL TECHNIQUE
The patient was appropriately pre-treated with a 60 second rinse of 0.12% chlorhexidine and subsequently anestheized with Xylocaine (1:50,000 epinephrine). A previously fabricated acrylic (GC Pattern Resin, Fuji, Japan) incisal index was tried in to verify fit (Fig. 2). The portion of the tooth coronal to the horizontal fracture was removed and then the root portion of #12 was atraumatically extracted with Periotomes (Dentsply Frialit Ceramed). The socket was debrided of all granulation and remnant tissue.
The osteotomy site was initiated at a position against the palatal wall and approximately 2-3mm coronal to the most apical portion of the socket. The alignment of the drill with the cingulum of the tooth being replaced facilitated proper implant placement in this anterior site. A tapered implant with a roughened surface (Tapered Replace Select, Nobel Biocare, Yorba Linda CA) was chosen because of the ease with which primary stability can be achieved and the promotion of the early clot formation and stabilization within the osteotomy site, rapidly turning over to de novo bone formation. The osteotomy drilling sequence follows the palatal aspect of the bone in a concerted effort to preserve the thin fragile buccal plate. If the implant is placed too far facially, stress upon the thin cortical bone may result. The thin cortical plate may resorb under loading, causing soft tissue recession and resulting aesthetic problems due to the longer crown and margin exposure.8 The depth of the implant is positioned so that the shoulder of the fixture is 3mm apical to the buccal gingival margin (Fig. 3).
The transfer assembly was custom milled chairside and the patients own clinical crown was reamed out and relined with provisional acrylic (Jet, Lang USA) utilizing the pre-made incisal index to precisely reposition the clinical crown on the implant-abutment assembly. This newly relined and trimmed clinical crown was provisionally cemented on the abutment and composite was applied to lateral aspects of #12 to the adjacent teeth to prevent or counteract any rotational forces (Fig. 4). The absence of centric and eccentric contacts was determined by the interposition of 200um articulating paper. The patient was instructed not to chew on the provisional prosthesis for at least eight weeks.
RESTORATIVE PHASE
After healing for a period of three months the provisional crown and abutment assembly were removed and a final fixture level impression was taken of the implant in the position of #12 (Fig. 5). Additionally Veneer preparations were made on teeth #11, 21 and 22 and these were impressioned concomitantly with the implant. The definitive veneers and permanent implant supported crown were fabricated precisely to the dimensions prescribed by the provisional tooth/crown (ET Ceramic, Marco Beschizza). The implant abutment was custom fabricated utilizing the Procera (Nobel Biocare) process. The abutment was seated and the prosthetic screw was torques to 35Ncm, and the crown was cemented along with the ceramic veneers utilizing resin cement (Bisco Illusion clear). The same cement was utilized for both the implant crown and the veneers to maximize uniform aesthetics between all four restorations (Fig. 6).
DISCUSSION
Implant treatment has previously been separated into the surgical phase and the restorative phase. Depending on the complexity of the planned site, the surgical phase may require two to four procedures in conventional implant treatment. The restorative phase, particularly in the aesthetic zone, may require tissue sculpting and provisionalization to achieve the foundation not only for aesthetics, but also for long-term restorative success. Over the years, conventional implant treatment has proven to be a highly successful treatment option for replacing the natural tooth system.
Advancements in surgical techniques, bone grafting materials and bioengineering of the surgical site have allowed the implant surgeon to decrease treatment time and possibly surgical visits. Without proper communication amongst the surgeon, restorative dentist and laboratory technician, however, the resulting poor or improper treatment planning will lead to complex and/or compromised prosthetic procedures. Continued advancements in surgical template designs and the incorporation of provisional restorations during implant placement have allowed the implant team to better communicate the parameter for functional, biological and aesthetic success in implant restorations.
CONCLUSION
The immediate restoratio
n of dental implants is an exciting option that the implant team can offer patients seeking implant treatment. The incorporation of the unique provisional restoration during implant placement provides the patient with a stable, aesthetic temporary restoration. From a periodontal perspective the preservation of interdental bone, creation of maintenance of the soft tissue and formation of a sound biologic width are all benefits of immediate restoration-in addition to decreasing patient treatment time. Using a nonincision approach in the aesthetic zone, with appropriate preoperative buccal tissue contours, is an effective method to maintain supportive interdental architecture in the papillary region.
Acknowledgement
The author would like to mention his gratitude to Marco Beschizza MDT, for developing the restorations seen here.
Dwayne Karateew DDS, Dip. Perio, Dip. Prostho, obtained his DDS from Columbia University in New York and Diplomas in both Periodontics and fixed Prosthodontics from the University of Pennsylvania. He participates as a member on the Faculties of the University of British Columbia, University of Washington, the University of Pennsylvania and Columbia University. He practices in Vancouver, BC.
Oral Health welcomes this original article.
REFERENCES
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