Implant Therapy in the Aesthetic Zone: Maintaining Gingival Margins

One of the greatest challenges for the implant surgeon and restorative dentist is creating an aesthetic balance between the implant restoration and the existing natural teeth. A major part of this equation is the final gingival drape over the implant restoration. Although an abundance of studies show impressive survival rates, the management of the midbuccal gingival dimension has remained a challenging task.
This article will focus on several key factors influencing the final gingival drape and highlight 2 case studies demonstrating both success and failure.

KEY FACTORS INFLUENCING THE GINGIVAL DRAPE
Atraumatic extractions and placement: Proper surgical techniques result in minimal soft- and hard-tissue damage, maintaining the 5 bony walls to facilitate the osteotomy.

  1. Flapless access versus full-flap: A flapless approach to implant placement is gaining popularity due to several advantages. What impact does it have on midfacial recession?
  2. Immediate versus delayed placement: Both immediate and delayed placement allow for rigid fixation. How do these 2 different protocols impact the gingival drape of the final restoration?
  3. Provisionalization: A proper emergence profile that lends itself to mimic the gingival pressure of the natural tooth is another fundamental tenet of a final aesthetic restoration.
  4. Immediate versus delayed temporization: As in other medical procedures, today’s implant patient seeks “faster and better.” Placing an implant and a temporary restoration at the surgical visit is an increasing trend that poses new challenges. How does this impact the gingival drape?
Figure 1. Case 1: pre-op photo of left central incisor (tooth No. 9). Figure 2. Flapless atraumatic extraction.
Figure 3. Implant placement. Figure 4. Autologous from osteotomy for “gap.”

Atraumatic Extractions and Placement
Unequivocally, a critical protocol of maintaining gingival margins with implant restorations is removing teeth without unnecessary hard- or soft-tissue damage. (It is beyond the scope of this article to outline the protocols that lead to atraumatic tooth removal. Misch’s1 Contemporary Implant Dentistry provides a strong foundation on the topic.) The end goal is maintaining the 5 bony walls.1 Removing the tooth atraumatically is merely the beginning of an ideal aesthetic restoration. The geometry of implant placement significantly impacts the outcome. Many studies have demonstrated predictable aesthetics if the supporting tissues of the natural dentition are in a healthy state and the distance protocol is respected between implant and natural tooth. Most agree that ideal placement is 1.5 to 2.0 mm mesiodistally from the adjacent tooth and 3.0 mm from the free gingival margin. This is not a minor point. Placing an implant too facial, too subgingival, or not subgingival enough will cancel out all other perfectly executed protocols, and the result will be an apical buccal margin and aesthetic failure. Further, it is relevant to note that even the most skilled clinician, performing the “perfect extraction” can find unexpected recession in a thin biotype.

Flapless Approach
Reduced surgical time, bleeding, and swelling are clear advantages to the flapless approach. Many clinicians cite opposing views as to clinical outcomes with the flapless approach. Sunitha and Sapthagiri2 followed 40 patients that were divided into a flap and nonflap approach. Their2 findings revealed that sustained papillary height and reduced crestal bone loss result from a flapless protocol.
Chen et al3 looked at 85 patients receiving implants in the central or lateral position with a flapless approach. After one year they3 found recession in 6 of 25 thin biotypes compared with only 2 of 19 with thick biotypes. A review of the literature leaves the impression that flapless surgery results in successful integration with clinically insignificant crestal bone loss for up to 4 years. However, this could be attributed to patient biotypes and careful patient selection.4

Figure 5. Immediate provisional. Figure 6. Implant site at 12 weeks.
Figure 7. Abutment in place. Figure 8. Case 1: final result.

Immediate Versus Delayed Placement
For the purpose of this discussion, we will assume that immediate placement would only be considered when periodontal disease or endodontic failures are not the cause for tooth removal. Polizzi et al5 reported in 2000 that periodontally affected tissues might have a negative local influence on the remaining socket with infrabony defects. The cases we will review involve teeth lost secondary to structural failure; teeth with a history of root canal that fractured at the gingival margin or subosseously.
There are many voices for both approaches. The protocol for immediate implant placement dates back to 1989.6 It was advocated for its ability to reduce tissue loss following extractions.7 Van Kesteren et al8 reported no differences for midbuccal or interproximal soft-tissue margins. They8 also noted increased ridge resorption when no grafting was done under a delayed approach. In 2009, Tortmano et al9 cited an 18-month study in which this group found no statistical difference in the mesial and distal papillae between delayed and immediate replacement. Although the literature is filled with a wide range of treatment protocols, it is clear that utilizing procedures to maintain or augment the thin buccal plate and surrounding soft tissue at the time of or prior to extraction increases the predictability of an aesthetic outcome. Hsu et al10 reported that grafting buccal walls with less than 2.0 mm of thickness provided soft-tissue stability. When the remaining cortical plate measured less than 2.0 mm, they10 recommended both hard- and soft-tissue augmentation with immediate implant placement.

Provisionalization
Following an extraction, there are several choices for temporary tooth replacement. Some clinicians utilize a transitional removable appliance. Resin-bonded retainers also have their place in the provisional phase. Both have pros and cons. Very often the patient’s needs influence the provisional phase. The literature is clear that an ideal provisional on immediately placed implants needs to fill the space occupied by the extracted tooth and support the surrounding soft tissue without excess pressure. Stephen Chu has a wealth of knowledge on the impact of the provisional on the final gingival drape. He notes the critical importance of beginning with a clean subgingival provisional surface and appropriate vertical tissue thickness. Chu et al11 state that less than a 3.0 mm dentogingival complex supra crestal prohibits tissue adhesion, which negatively impacts the final gingival drape.

Figure 9. Case 2: pre-op photo of right central incisor (tooth No. 8). Figure 10. Minimal flap; 5 intact bony walls.
Figure 11. Fixture placed too far labially. Figure 12. Connective tissue graft.
Figure 13. Implant placed, grafted, and sutured. Figure 14. Case 2: final result. (Note apical margin.)

Immediate Versus Delayed Temporization
The literature is flush with opposing views on this aspect of an aesthetic final drape. Block et al12 followed 55 patients who were split into 2 groups over a 2-year period. One group had immediate implant placement and load while the other were first grafted and then placed 4 months later. Their findings showed no difference in hard-tissue changes. Also noteworthy was that the immediate load patients preserved 1.0 mm more facial gingiva.12 On the other hand, Kan et al13 followed the stability of the drape on 35 patients from 2 to 8 years postoperative and observed continued facial recession, noting biotype as a significant factor.
In 2011, Cosyn et al14 studied the biotype influence. They followed 25 patients over a 3-year period. The patients received immediate single-tooth implants in the aesthetic zone. All patients had a thick biotype with ideal gingival contours. Acceptable aesthetic outcomes were assessed in 79% of those patients.14
It is clear that atraumatic tooth removal is the primary prerequisite to an aesthetic gingival drape. The success or failure of any of the other 4 parameters is significantly impacted by careful patient selection. One should err on the side of caution.

CASE REPORTS
Case 1: A Success

Diagnosis and Treatment Planning—A 50-year-old female with a nonremarkable medical history presented with a chief complaint of a loose left central incisor (tooth No. 9) (Figure 1). The examination and radiographs revealed a history of 6 anterior full-coverage PFM crowns from cuspid to cuspid. The remainder of the patient’s dentition was absent of pathology, and her periodontal health was excellent. The left central incisor had a history of root canal, and it had fractured at the gingival margin.
The recommended and accepted treatment plan was a single implant-retained crown on the left central incisor.
Clinical Protocol—The tooth was removed with a flapless approach utilizing a periotome. The socket was thoroughly curetted. The socket was absent of any pathology, there were 5 intact walls, and the patient had a definitive thick biotype (Figure 2). The osteotomy was completed, and a 4.3 x 15 BioHorizons tapered internal implant was placed 3.0 mm below the adjacent cemento-enamel junction, slightly palatally (Figure 3). The remaining socket gap was filled with autologous bone gathered from the osteotomy sequence (Figure 4). The complementary titanium abutment was hand torqued and prepared intraorally. A polycarbonate crown (Ion Polycarbonate Crowns [3M ESPE]) was lined with acrylic resin (Jet Acrylic [Lang Dental]). The subgingival contours were carefully sculpted to mimic the extracted crown using Super T (American Consolidated Manufacturing) (Figure 5). A small lingual hole was drilled to act as a cement vent to ensure no excess would escape into the surgical site. Twelve weeks later, an open-tray impression was taken with polyether impression material (Impregum [3M ESPE]). The dental laboratory team was instructed to fabricate (CAD/CAM) a zirconia abutment and a zirconia coping (Lava [3M ESPE]) layered with a lithium disilicate glass-ceramic (IPS e.max [Ivoclar Vivadent]). The final restoration was inserted 6 weeks later. The abutment was torqued to 35 Ncm and the aesthetic zirconia crown was cemented (RelyX Unicem [3M ESPE]) (Figures 6 to 8).

Case 2: A Failure
Diagnosis and Treatment Planning—A 48-year-old male presented with a chief complaint of a loose right central incisor (tooth No. 8). An examination yielded a medical history with no contraindications to dental care. Tooth No. 8 had a history of a failed root canal, and a retreatment procedure done 5 years previously (Figure 9).
The recommended and accepted treatment plan was removal of tooth No. 8 and restoration with an implant-retained crown.
Clinical Protocol—A minimal flap was elevated from the mesial of the adjacent teeth; the tooth was removed and all bony walls were maintained (Figure 10). The osteotomy was completed for a 4.3 x 15.0 mm Biohorizon implant. The implant was inadvertently placed toward the buccal aspect of the socket (Figure 11). The gap between the implant and socket was filled with autologous and freeze-dried bone (MinerOss [BioHorizons]). It was observed that the remaining buccal plate was thin (< 1.5 mm), and a connective tissue graft was utilized to minimize recession. The flap was sutured with VICRYL (Ethicon) and an interim removable partial denture was created (Figures 12 and 13). After 10 weeks, a final open-tray impression was taken using a polyether impression material (Impregum). The dental laboratory team was instructed to fabricate (CAD/CAM) a zirconia crown over a titanium abutment. The crown was torqued to 35 Ncm and cemented (RelyX Unicem).
The final restoration revealed asymmetrical gingival drapes between the central incisors (Figure 14).
A number of weak links could have contributed to the apical gingival drape. It is the author’s opinion that the labial placement of the implant was foremost in influencing the less-than-ideal final result. Less-than-ideal tissue management also contributed to the apical margin. Choosing a provisional crown on an abutment could also have aided in sculpting the gingival tissue.

CLOSING COMMENTS
Successful implant dentistry in the aesthetic zone has evolved well beyond merely a fully integrated implant. Today’s clinician must reproduce the contours that exist in the natural dentition with symmetrical gingival drapes and papillae. Clearly, the final gingival drape is impacted by a host of critical factors. Overlooking any one of these can result in aesthetic failure. Even the experienced implant clinician should proceed with caution. Abundant preoperative diagnostic data and a sound step-by-step treatment plan is imperative to ideal aesthetic outcomes.


References

  1. Misch CE. Contemporary Implant Dentistry. 3rd ed. St. Louis, MO: Mosby Elsevier; 2008.
  2. Sunitha RV, Sapthagiri E. Flapless implant surgery: a 2-year follow-up study of 40 implants. Oral Surg Oral Med Oral Pathol Oral Radiol. 2012 Jul 19. [Epub ahead of print]
  3. Chen ST, Darby IB, Reynolds EC, et al. Immediate implant placement postextraction without flap elevation. J Periodontol. 2009;80:163-172.
  4. Becker W, Goldstein M, Becker BE, et al. Minimally invasive flapless implant placement: follow-up results from a multicenter study. J Periodontol. 2009;80:347-352.
  5. Polizzi G, Grunder U, Goené R, et al. Immediate and delayed implant placement into extraction sockets: a 5-year report. Clin Implant Dent Relat Res. 2000;2:93-99.
  6. Lazzara RJ. Immediate implant placement into extraction sites: surgical and restorative advantages. Int J Periodontics Restorative Dent. 1989;9:332-343.
  7. Schwartz-Arad D, Chaushu G. The ways and wherefores of immediate placement of implants into fresh extraction sites: a literature review. J Periodontol. 1997;68:915-923.
  8. van Kesteren CJ, Schoolfield J, West J, et al. A prospective randomized clinical study of changes in soft tissue position following immediate and delayed implant placement. Int J Oral Maxillofac Implants. 2010;25:562-570.
  9. Tortamano P, Camargo LO, Bello-Silva MS, et al. Immediate implant placement and restoration in the esthetic zone: a prospective study with 18 months of follow-up. Int J Oral Maxillofac Implants. 2010;25:345-350.
  10. Hsu YT, Shieh CH, Wang HL. Using soft tissue graft to prevent mid-facial mucosal recession following immediate implant placement. J Int Acad Periodontol. 2012;14:76-82.
  11. Chu SJ, Salama MA, Salama H, et al. The dual-zone therapeutic concept of managing immediate implant placement and provisional restoration in anterior extraction sockets. Compend Contin Educ Dent. 2012;33:524-532, 534.
  12. Block MS, Mercante DE, Lirette D, et al. Prospective evaluation of immediate and delayed provisional single tooth restorations. J Oral Maxillofac Surg. 2009;67(suppl 11):89-107.
  13. Kan JY, Rungcharassaeng K, Lozada JL, et al. 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.
  14. Cosyn J, Eghbali A, De Bruyn H, et al. Immediate single-tooth implants in the anterior maxilla: 3-year results of a case series on hard and soft tissue response and aesthetics. J Clin Periodontol. 2011;38:746-753.

Dr. Rasner is a general practitioner from Bridgeton, NJ. In 1998, he founded Realizing the Dream, a collection of professional management tools, including speaker services, books, and in-office training videos. He has won numerous speaking awards internationally. He can be reached at (800) 337-8435 or at realizingthedream.com.

Disclosure: Dr. Rasner reports no disclosures.