The Graftless Socket-Shield Technique: A 5-Year Case Series
J. Kobi Stern, DMD, MSc; Vladimir Deresciuc, DMD; Mira Ghaly, DMD, MS; Jeril Cooper, DMD; and Mark E. Peacock, DMD, MS
Abstract: The socket-shield technique, or partial extraction therapy technique, is emerging as an all-inclusive method of implant rehabilitation in sites where esthetics is a critically important factor. This article details two socket-shield cases that were completed without grafting the implant/"shield" compartment, and followed for up to 5 years. Volumetric stability of soft and hard tissues was maintained over the follow-up period and no complications were noted. As with any novel surgical technique, procedure protocols of socket-shield/partial extraction therapy are continually being tested and subjected to interpretation as part of the natural evolution of practice. A review of the literature and the biologic rationale behind grafting this technique is included.
The evolution of oral implantology techniques driven by the intention to maximize a surgical opportunity as well as patients' demand for reduced treatment time and prompt restorative results has led to immediate implantation becoming a viable alternative to a staged protocol.1 Filling the gap between bone and implant around an immediately placed implant using various combinations of bone grafting materials and membranes has become of great interest to researchers/clinicians attempting to minimize tooth socket remodeling.2 Tarnow and Chu provided histologic and clinical validation to the hypothesis of successful healing by secondary intention of gaps larger than 1.5 mm between the implant interface and intact buccal bone.3 Their study proved that bone-to-implant contact can be achieved without auxiliary measures of grafting and/or use of a membrane for tissue exclusion, as which occurs in the natural healing of an extraction site. The challenge facing clinicians in the esthetic zone is not osseointegration, but preservation of the alveolar ridge and gingival dimension given the diminished blood supply in that area.
To overcome this challenge, a preservation technique known as the socket-shield or partial extraction therapy technique was developed and reported on by Hürzeler et al in 2010.4 In this technique, an immediate implant is placed into a fresh extraction socket in which the buccal portion of the tooth fragment is sectioned and left in place with its associated periodontal ligament (PDL) space untouched and its blood supply preserved. Once the immediate fixture is placed in proximation with the buccal tooth section, a gap may or may not be present. Many practitioners choose to augment this gap, if one exists, with various regenerative procedures.
Post-extraction atrophy around implants in the esthetic zone is a tangible concern, given that buccal wall thickness is less than or equal to 1 mm around 90% of anterior maxillary teeth.5 When facial bone thickness is greater than 1 mm, the socket-implant gap can be maintained with or without grafting.6 Esthetic predictability around immediate implants, however, can be achieved via several techniques. Chu et al introduced the dual-zone grafting technique to reduce the potential remodeling of the ridge while enhancing the peri-implant soft-tissue stability.7 Buser et al implemented a different compensation protocol in which early implant placement was combined with flap mobilization and superficial buccal "contour augmentation" utilizing slow-resorbing deproteinized bovine bone to achieve long-term volumetric stability of soft and hard tissues.8
It might be natural to conclude that in some cases involving loss of a tooth, there would be no substitute for physiologic design. This philosophy has led to this hybrid approach of preserving tissue by leaving a portion of the tooth root in the socket. A report by Bäumer et al with 5-year post-implant placement data revealed encouraging results and a high success rate with the socket-shield technique.9
This case series reports on two socket-shield/partial extraction therapy cases completed without grafting of the "shield" gap; the cases were stable and healthy without any esthetic or biologic complications after 5 years of follow-up. A review of the literature discussing the biologic rationale behind the established protocol10 and this technique is included.
Clinical Presentation, Case Management, and Outcomes
The following two cases of socket shield/partial extraction therapy were performed at the Faculty Practice Clinic of the Dental College of Georgia at Augusta University in Augusta, Georgia, between 2016-2017. The patients were followed up to a period of 5 years and 4 months, and all changes to hard and soft tissues were documented. No complications have been noted, and the patients have reported no complaints. The patients consented verbally and in written form to the procedure and to full photographic documentation and manuscript submission.
Case 1
A nonrestorable tooth No. 9 in a 59-year-old male patient with a thin biotype was deemed hopeless due to external root resorption (Figure 1 and Figure 2) and was planned for extraction and immediate implant placement via socket-shield technique. The tooth was sectioned and removed after decoronating it 1 mm coronal to the crest. As described previously,9 with the use of a coarse diamond bur on a high-speed handpiece, the facial root fragment (ie, the shield) was grinded leaving a 2 mm thick tooth fragment and its PDL attached to bone, intact and uninterrupted (Figure 3). An implant, 4.3 mm x 13 mm (NobelActive®, Nobel Biocare, nobelbiocare.com), was placed immediately in the socket, away from the root fragment leaving a root-to-implant buccal gap larger than 4 mm (Figure 4). No bone biomaterial was placed in the gap, but a connective tissue graft (CTG) harvested from the patient's palate was used via modified tunnel technique to cover exposed roots and level the gingival margins from teeth Nos. 7 through 10 (Figure 5).11 At this time, using a 6.0 polylactic suture, the soft tissue was coronally positioned and approximated to the immediate provisional screw-retained crown that was used to seal the ungrafted gap (Figure 6).
After 4 months of uneventful healing, implant osseointegration and socket healing with a healthy, esthetically pleasing contoured peri-implant tissue was achieved (Figure 7 and Figure 8). A screw-retained full-ceramic crown was then delivered (Figure 9). Radiographic and clinical follow-up after 5 years revealed long-standing implant health and alveolar prominence contours with peri-implant marginal tissue stability (Figure 10 through Figure 14).
Case 2
A 48-year-old male patient presented with a nonrestorable tooth No. 8 (Figure 15), which was deemed hopeless and planned for extraction and immediate implant placement via the socket-shield technique. The tooth was sectioned atraumatically, as described previously in the first case, and the buccal root portion of 2 mm thickness was preserved uninterrupted and attached to the facial bone, leaving the PDL and associated blood supply intact. After the socket was thoroughly debrided, an implant, 4.3 mm x 13 mm (NobelActive), was placed immediately, away from the fragment without osseous grafting of the implant-root gap (Figure 16). An immediate provisional crown was inserted in infraocclusion, and a 6.0 polylactic suture was used to approximate the soft-tissue margins to the temporary crown, thus further sealing the socket.
After 4 months, allowing for complete socket healing and osseointegration to take place, healthy, esthetically pleasing contoured peri-implant tissue was achieved (Figure 17). At this time, permanent full-ceramic crowns were placed on teeth Nos. 8 and 9 (Figure 18). After 5 years stable and healthy peri-implant tissue contours were observed (Figure 19 through Figure 22).
Discussion
Loss of the PDL apparatus with its integrated blood supply can lead to drastic and irreversible bundle bone resorption, ultimately resulting in vertical and horizontal dimensional changes to the alveolar ridge. Yet, the capability exists for clinicians to effectively orchestrate events that can lead to elective preservation of the alveolar complex interface, as previously shown by Hürzeler et al4 and later by Bäumer et al.12 If the blood supply to the buccal plate is left uncompromised, implant placement and healing of the socket can occur via clot formation and osseointegration without ridge resorption.4 Achieving long-term stability of the facial plate of bone by preserving the PDL and its vascularty potential conceivably will allow the natural anatomy to be kept intact.
Currently, there is a dichotomy of opinions and methods among various research groups regarding the issue of grafting the shield gap. Advocates of grafting the shielded socket assert that the grafted site would theoretically be more resistant to fibrous connective tissue downgrowth in the shielded gap.13 On the other hand, Mitsias et al, in a study that was not in support of grafting the shield gap, were the first to demonstrate histologic analysis in a human socket-shield/partial extraction therapy case, which revealed mature compact bone in the apical two-thirds of the gap and non-infiltrated connective tissue in the coronal third.14 These authors theorized that while the use of an osseous graft might help to avoid fibrous infiltration, it could also increase the risk of infection and retard wound healing; they noted that the lack of inflammation present in the specimen could be considered encouraging. Additionally, other recent studies reporting successful outcomes and stable buccal bone plates around narrow nongrafted shielded gaps further substantiate the authors' findings.15,16
Conclusion
In conclusion, this 5-year case series showing stable ridge dimension around graftless shielded sockets suggests that shielded gaps around immediate implants may be left ungrafted. Additional histologic and long-term clinical studies are needed to determine the necessity and indications for grafting the shield-implant compartment.
Disclosure
The authors report no conflicts of interest.
About the Authors
J. Kobi Stern, DMD, MSc
Associate Professor, Dental College of Georgia at Augusta University, Augusta, Georgia; Former Director, Residency in Periodontics, Dental College of Georgia at Augusta University; Diplomate, American Board of Periodontology
Vladimir Deresciuc, DMD
Private Practice in Periodontics and Dental Implants, Asheville, North Carolina
Mira Ghaly, DMD, MS
Assistant Professor, Dental College of Georgia at Augusta University, Augusta, Georgia; Director, Residency in Periodontics, Dental College of Georgia at Augusta University; Diplomate, American Board of Periodontology
Jeril Cooper, DMD
Retired Professor, Dental College of Georgia at Augusta University, Augusta, Georgia
Mark E. Peacock, DMD, MS
Professor, Dental College of Georgia at Augusta University, Augusta, Georgia; Former Director, Residency in Periodontics, US Army, Fort Gordon, Georgia; Former Director, Residency in Periodontics, Dental College of Georgia at Augusta University; Diplomate, American Board of Periodontology
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