What is socket preservation?

What is socket preservation?

Socket preservation, also called alveolar ridge preservation (ARP) or simply ridge preservation, is a treatment in which the extraction socket is filled with a PRF membrane or bone substitute material in the same session as the tooth extraction. Then the socket opening is covered or sealed, so that the material is held in place during healing. There are several protocols: a barrier membrane over the granules, either resorbable collagen or non-resorbable, e.g. high-density polytetrafluoroethylene (PTFE); a collagen cone or collagen sponge placed in the opening; or an autologous soft tissue graft, e.g. a free gingival graft, that seals the socket (socket sealing).^{2, 3, 4, 6}

The procedure does not remove bone loss, but dampens it. The purpose is to preserve as much bone volume as possible for a possible later implant treatment and thus reduce the need for further bone building.

Why does bone disappear after an extraction?

The buccal bone wall is often thin and receives a significant part of its blood supply through the periodontal ligament. When the tooth is removed, the ligament disappears, and the wall resorbs. The process is fastest in the first few months.

The extent was assessed by Tan et al., who in Clinical Oral Implants Research reviewed the human studies that had measured it. Six months after an extraction, the jaw ridge had become 3.79 ± 0.23 mm narrower on average, while the buccal height was reduced by 1.24 ± 0.11 mm.¹ Calculated in percent, this corresponds to 29-63 % of the width and 11-22 % of the height.

How much can socket preservation preserve?

The most basic answer comes from a meta-analysis published by Avila-Ortiz et al. in the Journal of Clinical Periodontology in 2019. They reviewed 3,003 references and included 22 randomized trials of nine different forms of socket preservation, including bone substitute material with sealing, sealing alone, and autologous platelet concentrates, all compared with spontaneous healing. Only for the forms with bone substitute material were there enough comparable trials to calculate an overall estimate, and those are the ones the figures below apply to. The figures for PRF are under autologous platelet concentrates.²

• 1.99 mm less horizontal bone resorption than with spontaneous healing (95 % confidence interval (CI) 1.54 to 2.44)
• 1.72 mm less vertical loss in the middle buccal (95 % CI 0.96 to 2.48)

The effect depends on the starting point. In sockets with a buccal bone wall thicker than 1.0 mm, the average difference in horizontal bone resorption between sockets filled with allograft and sealed and untreated sockets was 3.2 mm, while the difference with a thinner bone wall was 1.29 mm.² This is clinically relevant because thin buccal bone walls are particularly susceptible to resorption after extraction.

What materials are used for socket preservation?

The materials fall into three groups: a particulate bone substitute material, something to cover or seal the socket, and autologous platelet concentrates such as PRF. The Avila-Ortiz analysis found no statistically superior method.²

Bone replacement with membrane or collagen sponge

The most favorable results for horizontal preservation were seen in the Avila-Ortiz analysis with particulate xenograft or allograft material covered by either a resorbable collagen membrane or a fast-resorbing collagen sponge.²

Sealing with soft tissue graft

Kim et al. randomized 54 patients into three groups in the International Dental Journal: spontaneous healing, DBBM-C (deproteinized bovine bone mineral with collagen) alone, and DBBM-C sealed with a free gingival graft (FGG). Both socket preservation groups preserved the width of the jaw ridge, with no significant difference in bone resorption between them. The authors assessed that sealing with FGG appeared to contribute to a more stable preservation of the bone material and better bone quality.³

Autologous platelet concentrates

Siawasch et al. included 33 randomized studies in Periodontology 2000, where a platelet concentrate, most often leukocyte- and platelet-rich fibrin (L-PRF), which has a solid form, was used as the only material in the socket. In most studies, they found signs of faster soft tissue healing, less postoperative pain, and less resorption compared with spontaneous healing. In their meta-analysis of six studies, horizontal bone resorption 1 mm below the ridge was on average 0.8 mm less with L-PRF than with spontaneous healing (95 % CI 0.4 to 1.2), and the buccal bone wall lost 0.6 mm less in height (95 % CI 0.3 to 0.9). However, the studies were heterogeneous, and the evidence could not be used to determine how platelet concentrates compare with other biomaterials.⁴ If PRF is new to you, start with our guide to PRF.

When is socket preservation relevant?

The literature documents an effect on bone preservation but cannot alone determine when the treatment is clinically indicated. It is a clinical assessment. The situations most often mentioned are:

• When an implant is planned in the same position
• When the buccal wall is thin, damaged, or missing
• In the aesthetic zone, where a collapse of the ridge is visible from the outside
• When treatment must be postponed for several months for other reasons

Conversely, a wide, intact socket without an implant plan can often heal spontaneously. Indications, contraindications, and material selection are determined by the treating dentist.

What do studies of the materials in our range show?

Several of the materials in our range have been used in published clinical studies of socket preservation.

maxgraft® and Jason membrane. In a randomized trial in the International Journal of Implant Dentistry, Solakoğlu et al. filled extraction sockets with one or two damaged bone walls in 36 patients with either maxgraft or another human allograft (Puros) and covered them with a Jason membrane. The granules were moistened with PRGF (plasma rich in growth factors). The implants were placed after four months and followed for three years in function. The bone level around the implants did not change significantly in the three years, and there was no difference between the two materials. However, in the maxgraft group, the ridge became significantly narrower in the first four months, and the authors supplemented with bone at the time of implant insertion. The trial had no spontaneous healing group, and the authors themselves write that it can be seen as a clinical pilot study.⁵

cerabone® and permamem. Zafiropoulos et al. reviewed 44 patients in Medicina, where the socket was filled with cerabone, the bovine bone mineral we also carry, and covered with a permamem membrane of high-density PTFE. The membrane was deliberately left partially exposed (open healing) and removed after about one month. In 25 of the patients, an implant was placed at the same time. After six months, the ridge was 0.3-0.7 mm narrower, while the height did not change significantly. No abscesses, allergic reactions, or lost membranes were seen. The study is retrospective and without a control group.⁶

The role of membranes in bone building is elaborated in the article on guided bone regeneration.

Products for socket preservation

A typical material selection consists of a particulate bone substitute material and a material to cover or seal the socket.

• 

  cerabone® +HyA

  Bovine bone granules combined with hyaluronic acid (HyA) for bone building and socket preservation.

  See product →
• 

  maxgraft® cancellous

  Human allograft granules as an alternative to xenograft material.

  See product →
• 

  Collprotect membrane

  Resorbable collagen membrane to cover the granules.

  See product →
• 

  collacone®

  Collagen cone shaped for the socket, for sealing the extraction socket.

  See product →

See the entire range of biomaterials →

If you work with human allografts, they are collected in the allograft collection, and the equipment for PRF is found under PRF equipment.

See courses in biomaterials and surgery →

Frequently asked questions

Sources