Introduction
The socket-shield technique mainly involves the intentional retention of a section or the remnant root at the time of immediate dental implantation. It is combined with the popular concept followed currently with immediate dental implants. Read this article to know the need for preserving the bone dimensions, the steps, the technique, and the potential complications.
What Is the Need for Bone Preservation?
Extraction of the tooth changes the dimensions of the oral alveolar ridge. This has a direct consequence while considering the prosthetic planning like dentures, crowns or bridges, or any future implant prosthesis and the emergence profile of the dental prosthesis. Hence, it is crucial to plan in the anterior region which is the most esthetic zone.
Trauma during the extraction of a tooth and the natural loss of periodontal ligament during extraction is attributed as the leading cause of bony remodeling and alteration. Hence dental surgeons after various randomized controlled trials and clinical research have elaborated many successful operative techniques that have been introduced over the last decade to prevent the natural resorption of alveolar bone.
What Are the Conventional Steps to Prevent Bone or Alveolar Resorption?
In the field of dental implants or prosthetic dentistry (dentures, crowns, and bridges), the three major steps include:
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Atraumatic extraction.
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Socket preservation.
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Bone grafting.
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Immediate implantation.
These four major steps are mainly to avoid the phenomenon of alveolar resorption by avoiding the collapse of the cortical plate region. This helps in maintaining the lost dimension of the bone. These techniques usually show significant results in maintaining the post-extraction alveolar bone. The research indicates that no technique has been completely capable of preservation of the alveolar socket due to the natural dimension loss that occurs post-extraction within the jaw bone. Healing of the extraction socket also leads to dimensional changes that mainly affect the placement of the implant and the profile of the final prosthesis.
How Is the Socket Shield Technique Done?
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Hürzeler et al. were the first to introduce this socket-shield technique which is mainly by retention of the buccal (inner lining of cheek) fragment of the tooth to prevent the buccal cortical bone (bone on cheek side) from undergoing natural resorption.
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This procedure involves root bisection (cutting in two parts) after which the buccal two-thirds of the root is left intact within the socket, and both the periodontium (connective tissue) as well as the bundle bone remain intact.
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Also to maintain the alveolar bone height, the buccal bone is left intact. The bundle bone is that portion of the alveolar bone process that surrounds every individual tooth. This part of the bone is where the collagen fibers of the periodontal ligament embed and needs preservation as per the socket shield technique.
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A buccal root fragment thus remains intentionally retained at the time of extraction and is attributed to function like a shield that preserves the buccal bone from undergoing natural resorption. This ensuring dental implant success as an implant can be immediately placed palatal to this retained root fragment.
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Research on animal models demonstrates cementum (mineralized layer covering root) formation just like a natural tooth upon those implant surfaces that were placed in contact with the intentionally retained root.
How to Plan Primary Stability of the Immediate Implant?
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Various researchers have found a high success rate of immediate implant placement post the use of the socket shield technique. It has many advantages over the conventional procedure of delayed prosthetic loading, by reducing the time employed for the final prosthesis. Also in the case of second-stage surgery and extraction socket, they provide the proper angulation for the implant direction and reduce the chance for abutment angulation to be as close to as possible to a natural tooth profile.
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While planning such emergence profiles in the anterior region, the primary stability of the implant should be at least around 35 Nano centimeter and it is achieved by extending osteotomy (cutting of bone) usually three millimeters or more.
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The space between the implant surface and the extraction socket wall will be filled with the bone graft with a lingual distance of more than one millimeter.
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According to a study, if the distance that is maintained by the operator between the implant surface and the socket wall is around 0.5 to 1 mm, there is no need for the bone graft. If the space is more than one millimeter, bone grafting is indicated.
What Are the Potential Complications?
The complication potentially associated with this technique is based upon histologic evaluation through a few case studies that showed pathologies such as sinus tracts, inflammation, and cysts associated with the tooth in question for root retention.
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If the root pieces show signs of continuous resorption and repair, they pose a risk of potential infection to those implants that are placed near the root.
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Loss of the socket shield either through resorption or extraction following infection may lead to the predisposition of the implant surface to infectious exposure.
Conclusion
The procedure of atraumatic extraction and successful preservation of post extraction tissue along with the thin buccal bone through the socket shield technique is useful for the successful restoration of dental implants. It is also useful for maintaining the alveolar bone height and crown-bridge success. The socket-shield technique shows promising results in the preservation of the post extraction socket. It holds pivotal value in current-day implant and esthetic dentistry. Further studies are still underway to find out the long-term success rate of the socket shield technique practiced now popularly.