Hom-Lay Wang
Prof. Hom-Lay Wang
United States of America


Classification Based on Extraction Socket Buccal Bone Morphology and Related Treatment Decision Tree

Steigmann L, Di Gianfilippo R, Steigmann M, Wang HL. Materials (Basel). 2022 Jan 19;15(3):733.


Tooth removal inevitably results in dimensional reductions of the alveolar process. Alveolar socket and ridge preservation procedures have been demonstrated to minimize ridge resorption after tooth extraction. However, although the present clinical literature suggests different treatment modalities for ridge preservation, a guideline on when to use which kind of grafting material is currently missing. Therefore, the aim of this study was to provide decision guidance for the most suitable ridge preservation technique.


The authors performed a systematic literature search to define parameters with respect to the phenotype of alveolar sockets that affect the outcome of ridge preservation procedures. Buccal bone thickness, buccal bone integrity, and dehiscences or fenestrations of the buccal bone wall were found to be crucial factors. Thus, based on the morphology of the labial bone wall a classification of extraction sites and a treatment decision tree was proposed.


Based on the buccal bone characteristics, three types of extraction sockets were described:

  • Socket type 1 (ST1): sockets with intact buccal bone wall
  • Socket type 2 (ST2): sockets with buccal bone fenestration
  • Socket type 3 (ST3): sockets with buccal bone dehiscences that affect bone height

Sockets type 1 are additionally subdivided based on the thickness of the bone wall, i.e. ≥ 1.0 mm (subclass ST1A) or < 1.0 mm (subclass ST1B) thickness. Similarly, sockets type 3 are further divided according to the dehiscence height, i.e. 1/3 (subclass ST3A), 1/3 – 2/3 (subclass ST3B) or ≥ 2/3 (subclass ST3C) of the buccal bone height. 


Based on the defined types of extraction sockets different treatment modalities were proposed.

Fig. 1. Proposed biomaterials and treatment approaches for the different socket types.

Socket type 1 (ST1) – Intact buccal bone wall

  • ST1A sockets (thick buccal wall) generally require no treatment. However, blood clot stabilization can be supported by applying a collagen sponge.
  • ST1B sockets (thin buccal wall) are filled with a particulate allograft or xenograft 1–2 mm below the alveolar crest, which is covered either by a collagen sponge or by an autogenous soft tissue graft especially in the aesthetic zone.

Socket type 2 (ST2) – Buccal fenestration

Sockets with a fenestration defect at the labial bone wall can be treated with a particular grafting material and a collagen membrane applied according to the ice-cream-cone technique, which omits the need of flap reflection.

Socket type 3 (ST3) – Buccal bone dehiscence

Treatment approaches for sockets presenting with a dehiscent buccal bone wall are based on the use of a particulate bone substitute in conjunction with a barrier membrane.

  • Sockets with a dehiscence of less than one third of the buccal bone height (ST3A) can be treated using the same approach as for the treatment of type 2 sockets.
  • If the dehiscence is between one third and two thirds of the buccal bone height (ST3B) a tunnel approach is proposed. After detachment of the periosteum from the bone using a tunneling instrument, the socket is filled with the bone grafting material. A dense PTFE membrane is tugged into the created space to cover the graft and at least 3 mm of native bone on the buccal and the oral side. The membrane is fixated by sutures and left exposed to the oral cavity.
  • Sockets with a dehiscence extending two thirds of the buccal bone height (ST3C) are approached by flap reflection both on the labial and oral side. The use of a dense PTFE membrane allows for open healing and thus the maintenance of the soft tissue architecture.


The anatomical structure of the buccal bone plate guides the treatment approach and biomaterial selection for the different socket types.

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