Dental implants are accepted today as an effective option for the restoration of single-tooth edentulous sites. The traditional treatment sequencing for replacement of a single missing tooth includes delaying restoration for 3 to 6 months following implant placement to ensure osseointegration. While good outcomes are routinely achieved using this protocol, patients may be unwilling to accept a treatment plan that includes substantial time without a restoration in place when compared to a standard fixed bridge. The use of a temporary removable partial denture prosthesis is not ideal and may be unacceptable to the patient. These interim conditions may lead some individuals to make treatment decisions based on expediency rather than maximum clinical benefit.
A body of literature is accumulating that describes good osseointegration outcomes following provisionalization of single-tooth implants on the day of implant placement.1-4 This approach permits immediate establishment of good aesthetic results on the day of implant surgery. Preliminary reports indicate that provisional crestal bone height and peri-implant soft-tissue contours can be maintained with same-day implant provisionalization at levels comparable to those seen when using delayed restorative protocols.1-4 Such efficient protocols would likely increase patient acceptance of implant treatment as an option for single-tooth replacement.
In a previous article, the authors described a technique for same-day implant placement and provisionalization of single-tooth implant sites and reviewed early outcomes data.5 The purpose of this article is to revisit this treatment protocol for single-tooth implants in order to expand upon the description of the technique and application over a wider range of clinical situations.
|Figure 1. Periapical radiograph depicting graft material placed into alveolar socket immediately after tooth extraction to prevent loss of osseous volume.|
At our institution, patients will now be considered for same-day, single-tooth implant placement and provisionalization for both a nonsalvageable tooth identified for extraction as well as for a mature edentulous site. If tooth extraction alone is to be performed as a first step, the site needs to heal for at least 8 weeks to allow an acceptable level of new bone ingrowth into the extraction socket. Bone grafting of the extraction socket will typically be performed to idealize the hard- and soft-tissue contours and to prevent collapse of the osseous walls, which results in a loss of bone volume (Figure 1). Bone grafting is also performed to correct any osseous defects that are encountered.
If adequate bone is present, same-day implant placement and provisionalization may be performed at the time of tooth extraction. Combining multiple steps in this fashion provides the most efficient treatment results while obtaining maximum patient satisfaction. Atraumatic removal of the tooth without damaging the bony walls of the alveolar socket is the critical step for success with this approach. Significant loss of the buccal wall of the socket would necessitate grafting, with a delay of implant/provisional crown placement for a minimum of 8 to 12 weeks.
Regardless of the timing of implant surgery in relation to tooth extraction, sufficient bone volume and density must be available in order to obtain good primary stability of the implant at the time of placement. The lack of deleterious micromovement of the implant during the healing phase is considered essential for successful osseointegration.6 The adequacy of stability obtained at implant placement can be assessed by reverse torque testing. If the seated implant can resist a minimum of 35 Ncm of removal force as applied with a torque wrench, then good primary implant stability has been obtained. If this minimum implant stability is not achieved, then same-day provisionalization should not be performed. Consideration must then be given to placement of a standard metal healing abutment as a one-stage surgical procedure or suturing the soft tissue over the implant using a traditional, 2-stage protocol.
IMPLANT SURGERY TECHNIQUE
On the day of surgery, the patient is premedicated with an oral antibiotic (1 g penicillin VK or 300 mg clindamycin for patients allergic to penicillin) and an oral anti-inflammatory medication (600 mg ibuprofen), followed by a 1-minute oral rinse with a local antimicrobial agent (0.12% chlorhexidine gluconate). Profound local anesthesia is obtained using 2% lidocaine with 1:100,000 epinephrine, with 0.5% bupivacaine 1:200,000 epinephrine also used to extend the length of anesthesia through the provisional crown fabrication phase of treatment.
|Figure 2. Conservative flap design to preserve presurgical contours of the papilla for an enhanced aesthetic outcome.||Figure 3. Flapless tissue punch technique designed for maximum preservation of soft-tissue contours with minimal surgical trauma.|
The soft tissue is reflected using either a conservative sulcular or papilla-sparing flap design (Figure 2). If sufficient attached mucosa is present, a tissue punch technique can be alternatively utilized using a 4-mm latch-handle punch mounted on a handpiece (Figure 3). The decision to select either of these techniques is based on the goal of creating the best possible final soft-tissue architecture for the interdental papilla and crown emergence profile while limiting soft-tissue trauma.
|Figure 4. Periapical radiograph demonstrating position of pilot drill during preparation of the osteotomy site.||Figure 5. Sequential enlargement of osteotomy site to desired dimension using implant twist drill (3.2-mm Tiger twist drill, Astra Tech).|
A disposable pilot drill is introduced to the site, penetrating the bone to a depth of approximately 10 mm. A periapical radiograph is obtained to assess entry angulation and to determine that no vital anatomic structures are encroached upon (Figure 4). After confirmation of proper position and angulation, the pilot drill is used to establish the final depth corresponding to the length of the implant anticipated for placement. The osteotomy site is then sequentially enlarged to the desired implant diameter (Figure 5). Copious irrigation is utilized throughout the bone preparation phase.
|Figure 6. Introduction of implant into osteotomy site (4.0-mm diameter x 13-mm length MicroThread ST implant, Astra Tech).||Figure 7. Periapical radiograph demonstrating implant seated to the crestal bone.|
In maxillary sites with less dense bone (types 3 and 4),7 the final diameter can also be obtained using osteotomes. These instruments serve to compact the bone to artificially increase bone density for implant stabilization. The implant is introduced to the prepared site and seated to the level of the crestal bone using either a hand-held torque driver or a driver attached to a handpiece (Figures 6 and 7). Adequate stability of the implant for same-day provisionalization is then assessed by applying a reverse torque pressure using the hand-held torque wrench. Resistance to 35 Ncm of torque without movement indicates that good implant stability has been obtained and fabrication of the provisional restoration can proceed.
PROVISIONAL RESTORATION TECHNIQUE AND FOLLOW-UP
|Figure 8. Temporary implant abutment screwed into place onto implant.||Figure 9. Temporary abutment prepared in the mouth to create sufficient occlusal clearance for the provisional crown.|
|Figure 10. A selected polycarbonate crown form is seated over the temporary implant abutment. Note the creation of the hole in the occlusal surface to access the retention screw.||Figure 11. Autopolymerizing acrylic resin introduced through the screw access hole to lute the provisional crown to the abutment.|
A temporary implant abutment cylinder is screwed into place (Figure 8). The abutment cylinder is then prepared using a high-speed handpiece and copious irrigation to create the appropriate occlusal clearance and contour in a manner similar to a tooth preparation for a crown (Figure 9). The provisional crown can be fabricated directly in the mouth as either a screw- or cement-retained restoration. The decision to select either design is based on the goal of creating the best possible aesthetic result. A polycarbonate crown form can be selected for provisional crown fabrication. Alterna-tively, a denture tooth can be hollow ground to fit over the prepared abutment. If the provisional restoration is to be screw-retained, a screw access hole is then made through the crown form (Figure 10). Through this hole, autopolymerizing resin is inserted, luting the abutment and restoration together (Figure 11).
|Figure 12. The provisional crown finished outside of the mouth.||Figure 13. The provisional crown screwed into place.|
|Figure 14. Occlusion of the provisional crown assessed using articulating ribbon.||Figure 15. A provisional implant crown fabricated on a working cast. This restoration was then screwed into place on the implant on the day of surgery.|
After polymerization, the abutment and attached resin crown are unscrewed, resin is added to fill in any remaining voids, and any excess material is trimmed away (Figure 12). The restoration is then finished, polished, and screwed into place on the implant (Figure 13). It is recommended that the retention screw be tightened to 35 Ncm using a torque wrench. Research has shown that the tightening of retention screws using finger pressure alone results in an increase of screw loosening during the interval between temporization and definitive crown fabrication.8 Tightening of the retention screw with a torque wrench causes no adverse effect on the newly seated implant while serving to eliminate loosening of the screw. The screw access hole is sealed using a temporary restorative material that facilitates easy removal for screw access at a later date (Fermit Temporary Restorative Material, Ivoclar Vivadent). Care is taken at this time to reduce identified centric and eccentric occlusal contacts (Figure 14).
If the provisional crown is to be cement-retained, the resin crown form is selected and fitted over the temporary abutment without the creation of a screw access hole. The restoration is made in the same manner used for the temporization of a tooth prepared for a crown. The provisional crown form is lined with autopolymerizing resin and then placed over the abutment cylinder, taking care to remove and reinsert the crown frequently during polymerization to prevent it from curing onto the cylinder. The restoration is then finished, polished, and cemented into place on the implant. A luting agent specifically designed for implant prosthetics is suggested to cement these provisional crowns (Improv Temporary Cement, Nobel Biocare USA). As in the case of a screw-retained restoration, excessive centric and eccentric occlusal contacts are removed following identification.
The provisional crown can also be fabricated indirectly on a working cast. With this approach, an implant-level im-pression transfer coping is screwed into place on the implant, and a full-arch impression is made. After removal, an implant replica is screwed onto the transfer coping, and the impression is poured in a fast-setting dental stone (Snap-Stone, Whip Mix). An impression of the opposing arch is also made. The prepared temporary abutment is screwed onto the implant replica in the working cast, and the steps for fabrication of either a screw-retained or cement-retained provisional crown are performed as de-scribed previously (Figure 15).
Postoperative medications include oral antibiotics (500 mg penicillin VK qid x 1 week or 150 mg clindamycin qid x 1 week), oral analgesics (ibuprofen 600 mg TID taken as needed), and a 0.12% chlorhexidine gluconate oral rinse (bid x 2 weeks). Patients are instructed to brush the treatment site immediately and gently, but to avoid flossing the site for 4 weeks to permit undisturbed soft-tissue healing. After 4 weeks patients can resume normal brushing and flossing of the site. Patients are also instructed to avoid masticating on the treatment side for 3 weeks, after which time they may advance to chewing soft foods on the treatment side of the mouth. Patients are seen approximately 2 weeks postoperatively to assess initial healing and to remove sutures (if placed). The function of the provisional crown is also assessed at this time.
Definitive restorative treat-ment can usually commence approximately 8 to 12 weeks following implant placement/provisionalization. This is true for either the mandible or maxilla. The restoration of choice is a ceramo-metal crown that can be designed either to be cemented or screw-retained in order to maximize the final aesthetic result. As with the provisional crown, care is taken to reduce occlusal contacts on this restoration when compared to adjacent teeth. This is necessary to take into account the differences seen between implant-retained crowns and the natural dentition in response to loading. During mastication, occlusal loading will cause teeth suspended by a periodontal ligament to move slightly within their bony sockets. The implant, having no ligamentous connection to the bone, will exhibit no similar movement. If the implant crown is designed to accept similar loading as the dentition at initial occlusal contact, the loading of the immovable implant will then increase under maximum occlusal contact as the teeth experience normal physiologic movement away from the load. The result is excessive implant loading during normal mastication.
Recent Clinical Experiences
In an ongoing effort to monitor efficacy of this protocol, a pilot quality assurance review was performed of outcomes for 10 patients who underwent single-tooth implant rehabilitation and same-day provisional crown placement for one implant system currently being used (Fixture MicroThread Implants, Astra Tech). To date, 8 of these 10 patients have undergone definitive restorative care. The 2 remaining patients continue to wear their provisional crowns, delaying definitive treatment due to financial considerations. The mean follow-up period for this patient population was 17.3 months as measured from the point of implant placement/provisionalization (range: 10 to 38 months). Various sites were treated both in the maxilla and mandible using implants of varying lengths and diameters (Table 1). All implants were judged clinically to be osseointegrated with maintenance of good soft-tissue aesthetic contour and health throughout the follow-up period.
Crestal bone height was measured using periapical radiographs obtained at the time of placement. The distance from the implant shoulder to the crestal bone along both the mesial and distal implant surfaces was measured to the nearest 0.5 mm using a millimeter ruler. These 2 measures were combined to obtain a mean baseline marginal bone height value for each implant. This step was repeated using a periapical radiograph obtained at the time of the last patient follow-up examination. These results revealed only minimal loss of crestal bone height in 2 cases (Table 2).
All patients subjectively rated their results as highly satisfying and commented on the fact that restoration on the day of implant placement was a significant reason for overall satisfaction with treatment. All 10 patients remain under maintenance follow-up care. The results of this pilot mirror our overall experience with this approach. Integration outcomes have been found to be as good for implants that are provisionalized on the day of implant placement as for those where a delayed restoration protocol was employed.
The provisionalization of im-plants on the day of implant placement represents a viable treatment approach. Same-day implant placement/provisionalization should be a treatment option and may ultimately become the preferred treatment option for patients requiring single-tooth implant rehabilitation.
1. Wöhrle PS. Single-tooth replacement in the aesthetic zone with immediate provisionalization: fourteen consecutive case reports. Pract Periodontics Aesthet Dent. 1998;10:1107-1114.
2. Kan JY, Rungcharassaeng K, Lozada J. Immediate placement and provisionalization of maxillary anterior single implants: 1-year prospective study. Int J Oral Maxillofac Implants. 2003;18:31-39.
3. Proussaefs P, Kan J, Lozada J, et al. Effects of immediate loading with threaded hydroxyapatite-coated root-form implants on single premolar replacements: a preliminary report. Int J Oral Maxillofac Implants. 2002;17:567-572.
4. Calandriello R, Tomatis M, Vallone R, et al. Immediate occlusal loading of single lower molars using Branemark System Wide-Platform TiUnite implants: an interim report of a prospective open-ended clinical multicenter study. Clin Implant Dent Relat Res. 2003;5(suppl 1):74-80.
5. Toljanic JA, Baer RA. Immediately restored single-tooth implants. Shortening treatment time to increase patient acceptance. Dent Today. Aug 2002;21:42-45.
6. Friberg B, Jemt T, Lekholm U. Early failures in 4,641 consecutively placed Branemark dental implants: a study from stage 1 surgery to the connection of completed prostheses. Int J Oral Maxillofac Implants. 1991;6:142-146.
7. Branemark P-I, Zarb GA, Albrektsson T. Tissue-Integrated Prostheses: Osseointegration in Clinical Dentistry. Chicago, Ill: Quintessence; 1987:202,214,228.
8. Toljanic JA, Baer RA. Abutment screw loosening following immediate provisionalization of single tooth dental implants. A comparison of hand versus torque tightening. Applied Osseointegration Research. 2004;4:46-48.
Test No. 67.1
After reading this article, the individual will learn:
• guidelines for planning same-day placement and provisionalization of single-tooth implants, and
• clinical technique for implant placement and provisional restoration of a single-tooth implant.
1. Traditional treatment sequencing for replacement of a single missing tooth with an implant includes delaying restoration of the implant for ______:
a. 1 to 2 months.
b. 2 to 4 months.
c. 3 to 6 months.
d. at least 8 months.
2. When adequate bone is present, same-day, single-tooth implant placement and provisionalization can be performed:
a. at the time of tooth extraction.
b. 2 to 4 weeks after tooth extraction.
c. 6 weeks after tooth extraction.
d. 8 weeks after tooth extraction.
3. If a seated implant can resist a minimum of _____ Ncm of removal force as applied with a torque wrench, then good primary implant stability has been achieved.
4. After a single-tooth implant has been placed and the provisional restoration has been fabricated, patients should avoid flossing the site for _______ to permit undisturbed soft-tissue healing.
a. 2 weeks
b. 4 weeks
c. 6 weeks
d. 8 weeks
5. Definitive restorative treatment can usually commence approximately ______ following single-tooth implant placement and provisionalization.
a. 4 to 6 weeks
b. 6 to 8 weeks
c. 8 to 12 weeks
d. 4 months
6. When considering the maxilla versus the mandible, definitive restorative treatment following single-tooth implant placement and provisionalization should take place:
a. 2 weeks later in the maxilla.
b. 4 weeks later in the maxilla.
c. 2 weeks later in the mandible.
d. at the same time for either the maxilla or the mandible.
7. Preliminary reports indicate that crestal bone height and peri-implant soft-tissue contours can be maintained with same-day implant provisionalization at levels ______ those seen when using delayed restorative protocols.
a. significantly less than
b. moderately less than
c. comparable to
d. moderately better than
8. If a significant amount of the buccal wall of the socket is lost during tooth extraction, thus requiring grafting, placement of an implant and fabrication of a provisional crown should be delayed for a minimum of:
a. 4 to 6 weeks.
b. 6 to 8 weeks.
c. 8 to 12 weeks.
d. 12 to 16 weeks.
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