Site Preservation and Ridge Augmentation

Armamentarium

  • #9 Periosteal

  • #15 Scalpel blade

  • #701 Bur

  • Appropriate sutures

  • Barrier membranes (resorbable/nonresorbable)

  • Bone graft substitutes (allograft, xenograft, alloplast, or autogenous bone)

  • Bone scraper

  • Elevators

  • Fixation pins (tacks or screws)

  • Forceps

  • Gelfoam/collagen plug

  • Local anesthetic with vasoconstrictor

  • Minnesota retractor

  • Needle holder

  • Periotomes

  • Tissue forceps

  • Woodson elevator

History of the Procedure

Changes that occur after tooth extraction have been well documented since the early 1900s. Both animal and human studies have examined the healing mechanisms and pattern of alveolar ridge resorption after a tooth is extracted. In 1923, Euler examined the healing process of extraction wounds in dogs and determined that there were seven distinct phases. Clafin, the first to report on dogs and humans, noted that healing was slower in humans than in dogs. In 1967, Pietrokovoski and Massler published a study on the morphologic changes taking place after tooth extraction on duplicate study casts; they concluded that the buccal plate showed greater resorption than did the lingual plate, both in the maxilla and the mandible. These findings were later confirmed in a histologic study by Araujo and Lindhe. The term socket preservation, attributed to Cohen, involves the placement of a filler into a fresh extraction socket with the objective of minimizing bone remodeling after tooth extraction. A number of materials have been studied for this purpose, and they have shown comparable results.

By definition, a socket is a cavity. Therefore, to preserve the socket means to maintain the socket intact, as a cavity. The term socket augmentation best describes the goal of the procedure, which is to fill a cavity by generating new bone. Several augmentation procedures have been proposed to compensate for ridge deficiencies. The basic principles for guided tissue regeneration (GTR) were established by Melcher, who described the need to protect the healing sites from unwanted cells to allow for regeneration of the desired tissues. Since the introduction of the first barrier membranes in the early 1980s, research in the field of guided bone regeneration (GBR) for ridge augmentation has grown exponentially. Barrier membranes play a key role in successful outcomes for GBR. Their biocompatibility, ability to maintain space, occlusivity, and manageability dictate bone regeneration. Both resorbable and nonresorbable membranes have been used in GBR procedures. Resorbable barriers can be made of natural or synthetic materials, such as collagen, polyglycolide, and polylactic acid. Nonresorbable membranes usually are made of polytetrafluoroethylene (PTFE) and titanium mesh. During the 1990s, guided bone regeneration was proven to be a successful and viable technique for ridge augmentation.

An array of grafting materials has been investigated for use in GBR. Autogenous bone, allografts, xenografts, alloplasts, and growth factors have been used alone or in combination to promote bone regeneration and have shown comparable results. To date, the data are insufficient to prove the superiority of one material over another. An ideal graft material should remain in place to provide a scaffold for bone formation and to prevent the volume reduction that occurs over time.

History of the Procedure

Changes that occur after tooth extraction have been well documented since the early 1900s. Both animal and human studies have examined the healing mechanisms and pattern of alveolar ridge resorption after a tooth is extracted. In 1923, Euler examined the healing process of extraction wounds in dogs and determined that there were seven distinct phases. Clafin, the first to report on dogs and humans, noted that healing was slower in humans than in dogs. In 1967, Pietrokovoski and Massler published a study on the morphologic changes taking place after tooth extraction on duplicate study casts; they concluded that the buccal plate showed greater resorption than did the lingual plate, both in the maxilla and the mandible. These findings were later confirmed in a histologic study by Araujo and Lindhe. The term socket preservation, attributed to Cohen, involves the placement of a filler into a fresh extraction socket with the objective of minimizing bone remodeling after tooth extraction. A number of materials have been studied for this purpose, and they have shown comparable results.

By definition, a socket is a cavity. Therefore, to preserve the socket means to maintain the socket intact, as a cavity. The term socket augmentation best describes the goal of the procedure, which is to fill a cavity by generating new bone. Several augmentation procedures have been proposed to compensate for ridge deficiencies. The basic principles for guided tissue regeneration (GTR) were established by Melcher, who described the need to protect the healing sites from unwanted cells to allow for regeneration of the desired tissues. Since the introduction of the first barrier membranes in the early 1980s, research in the field of guided bone regeneration (GBR) for ridge augmentation has grown exponentially. Barrier membranes play a key role in successful outcomes for GBR. Their biocompatibility, ability to maintain space, occlusivity, and manageability dictate bone regeneration. Both resorbable and nonresorbable membranes have been used in GBR procedures. Resorbable barriers can be made of natural or synthetic materials, such as collagen, polyglycolide, and polylactic acid. Nonresorbable membranes usually are made of polytetrafluoroethylene (PTFE) and titanium mesh. During the 1990s, guided bone regeneration was proven to be a successful and viable technique for ridge augmentation.

An array of grafting materials has been investigated for use in GBR. Autogenous bone, allografts, xenografts, alloplasts, and growth factors have been used alone or in combination to promote bone regeneration and have shown comparable results. To date, the data are insufficient to prove the superiority of one material over another. An ideal graft material should remain in place to provide a scaffold for bone formation and to prevent the volume reduction that occurs over time.

Indications for the Use of the Procedure

Changes in alveolar ridge dimensions occur in well-defined patterns. If not corrected, these alterations can lead to unfavorable functional and esthetic results. Ridge augmentation procedures and site preservation are intended to correct such deformities so as to maximize the functional and esthetic outcome of dental implant therapy.

Socket Augmentation

The main indication for socket augmentation is to minimize the remodeling of hard and soft tissue that occurs after tooth extraction. Placement of a graft material into a socket allows for stability of the blood clot and provides a scaffolding for new bone formation. Unfortunately, remodeling of the socket occurs even if the site is grafted, because the bundle bone present in the crest and inner portion of the socket is resorbed and replaced by woven bone.

Guided Bone Regeneration for Vertical and Horizontal Defects

Remodeling after tooth extraction can have devastating effects on the contours of the alveolar ridge and may prevent dental implant placement. In some instances, to achieve optimal functional and esthetic outcomes, regeneration of the defects must be accomplished. Guided bone regeneration, in association with dental implant procedures, can be used to augment deficient alveolar ridges, to cover implant fenestrations and dehiscences, to allow immediate implant placement in residual osseous defects and postextraction sites, and to treat peri-implant disease. These defects may be localized to a single tooth or may extend to multiple teeth. If the defect is horizontal, it may lead to thread exposure, dehiscence, or fenestration. Ideally, the residual ridge width should be no less than 6 mm for a 4-mm diameter implant. If the defect is vertical, it may lead to placement of shorter implants than desired, long clinical crowns, and unesthetic results. Net bone gain reports after GBR procedures are scarce. For vertical GBR, bone augmentation can range from 2 to 7 mm, and for horizontal GBR, from 2 to 4.5 mm.

Limitations and Contraindications

With any surgical procedure, limitations are determined by biology itself. The healing mechanisms after injury (in this case, ridge augmentation procedures) are very similar from patient to patient. The difference is in the individual’s ability to heal. Age, certain systemic diseases, medications, social habits, and oral hygiene habits play key roles in the individual’s healing potential. Clinicians should consider these factors before recommending treatment for their patients. In addition, some limitations apply to the procedure itself. Socket augmentation does not prevent remodeling after tooth extraction, but it may minimize it. GBR procedures are limited in the amount of bone that can be generated. When GBR alone cannot fulfill the requirements of the defect, an alternative technique should be selected.

Soft tissue management is the key to successful bone regeneration. An adequate zone of keratinized mucosa and tension-free closure of the flap margins minimize or prevent wound dehiscence. Soft tissue should be examined carefully before GBR procedures are initiated. In some instances, it may be necessary to improve the quality and quantity of soft tissue before regenerative procedures.

Technique: Socket Augmentation

Step 1:

Tooth Extraction

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Jun 3, 2016 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Site Preservation and Ridge Augmentation
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