Extraction Socket Preservation: When, why, how?

2. Acellular dermal matrix

Luczyszyn et al. introduced a technique using an acellular dermal matrix to cover the socket graft with resorbable hydroxyapatite. The hydroxyapatite affected the ESP outcome, and the matrix contributed to thickening of the soft tissue around the socket.

3. Resorbable barrier membrane

Although many researchers have demonstrated significant ESP outcomes using only a resorbable membrane to cover the socket, without bone grafting, the outcome could be maximized with bone grafting. In cases of biphasic calcium phosphate grafting with a cross-linked collagen membrane, sufficient ridge preservation occurred with prolonged barrier function even with early membrane exposure. Acceptable ESP outcomes were re- ported with polylactide and polyglycolide sponges and native bilayer collagen membranes.

4. Non-resorbable barrier membrane

Faciola Pessôa de Oliveira et al. reported successful ESP outcomes after covering with a polytetrafluoroethelene (dPTFE) membrane after minimally traumatic extraction.

5. Collagen sponge

The Bio-Col method was suggested as an effective ESP technique to pack a collagen sponge above the xenogeneic bone graft into 1/2 to 2/3rd of the extraction socket. Complete removal of inflammatory tissue and pathologic lesions should be performed with minimally invasive procedures after tooth extraction. All soft tissues along the socket wall are removed, and spontaneous bleeding is induced to release healing factors from the bone marrow. Suturing is performed with a collagen plug, barrier membrane, or autogenous gingival tissue after application of bone substitute. Primary wound closure is not essential if proper suturing is achieved to prevent dislodgement of the membrane or collagen plug above the substitutes. It was said that using a osteoconductive bone substitutes such as deproteinized bovine bone material (DBBM) (Bio-Oss; Geistlich Pharma AG, Wolhusen, Switzerland) or other synthetic materials with slow resorption and covering the upper part with a resorbable barrier membrane or connective tissue graft, or selecting the BioCol procedure maintains the volume of the extraction socket well and facilitates implant placement in the future5. Implants can be placed with no complications at 4-6 months after grafting.

Controversy

1. Positive view

Since socket preservation grafting is performed to minimize ridge atrophy after tooth extraction, several advantages have been suggested, including that ESP reduces the need for additional bone graft, facilitates the implant procedure, and improves marginal bone loss and survival/success rate of implants8. Avila-Ortiz et al. reported that the ESP group had statistically significantly less bone resorption of 1.89 mm horizontally, 2.07 mm at labial side and 1.18 mm at lingual side vertically compared to the simple extraction group. In particular, the result of ESP was excellent in the maxilla. When ESP is performed in the maxillary posterior region, sinus elevation surgery can be minimized or avoided, enabling flapless implant surgery. Natural bone healing is insufficient in extraction sockets with periodontal or inflammatory disease because soft tissue invasion into the socket impedes bone healing even long after the procedure. To maintain the volume of the extraction socket, thickness of the buccal bone wall is the most important factor. ESP is generally recommended for sockets with thin buccal bone wall (≤1 mm).

2. Negative view

Some researchers have argued a negative view of ESP. ESP can reduce the bone resorption, but not completely prevent. Rather, bone substitutes could contribute to impaired natural bone healing. Few studies reported no differences in feasibility, success/survival rates, and marginal bone loss between implants with and without ESP. Simon et al. questioned the usefulness of performing bone graft before implant placement (guided bone regeneration +ESP) and observed that bone height loss occurred more than bone width even after bone graft. Therefore, it was argued that filling the graft material not only inside the extraction socket but also outside the extraction socket and covering it with a barrier membrane could prevent bone loss as much as possible.

Conclusion

1. ESP is not required in all extraction cases, but should be considered in the following cases:

• Aesthetic concern
• Severe destruction of residual bone walls after tooth extraction
• Delayed implant treatment

2. With ESP, the necessity for additional bone grafting is reduced at implant placement. 3. ESP does not affect the success rate or marginal bone loss of implants. 4. No consensus has been made on the standard protocol among ESP techniques. 5. Socket sealing can protect bone substitutes and contribute to soft tissue healing through autogenous gingival tissues, barrier membranes, collagen sponges, etc. 6. During ESP, primary closure is not essential, but minimally traumatic procedures are very important. 7. Dental implants are recommended to be placed 4 months after ESP.

Based on current evidence, extraction socket preservation/augmentation is suggested not only in clinical cases with dental implants being planned but also to preserve alveolar bone for removable prosthesis fixation or to support soft tissue around fixed dental prosthesis. Further studies are needed to validate the reliability of proposed clinical decision tree for extraction socket augmentation.

Frequently asked questions

Is socket preservation required after every extraction?

No. The decision depends on the restorative plan, socket anatomy, integrity of the facial plate, soft-tissue phenotype, aesthetic risk, infection control and the anticipated need for implant or prosthetic rehabilitation.

Does socket preservation completely prevent ridge resorption?

No. It may reduce dimensional change, but physiological post-extraction remodelling still occurs.

When should the socket be assessed?

Assessment begins before extraction and continues immediately after atraumatic removal of the tooth. The clinician should evaluate the socket walls, soft tissues, defect morphology, infection and relationship to adjacent anatomical structures.

Is a membrane always required?

No. Membrane selection depends on defect morphology, graft containment, soft-tissue management and the chosen technique. The benefits must be balanced against exposure risk and procedural complexity.

How is socket preservation different from immediate implant placement?

Socket preservation maintains the site for later rehabilitation, whereas immediate placement introduces an implant during the extraction appointment. Immediate placement does not eliminate the need to assess and manage peri-implant gaps and missing socket walls.

Related surgical reading

Review the biological principles and material categories in bone grafts in surgical dentistry.

Socket preservation is most useful when mapped to a future implant placement and loading plan.

Socket preservation should be selected before treatment within the overall extraction and rehabilitation plan.

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