When should I place a place dental implants? 


The classification of timing of implant placement after tooth extraction, established by the third ITI Consensus Conference in 2003, includes four different time frames for implant placement.1  These include: immediate placement, early placement (4-8 weeks post-extraction), early placement (typically 12-16 weeks post-extraction), and late placement (more than 16 weeks).1,2 This was then updated by Chen and Buser in 2008, and released in 2009, to develop a timing classification based on wound-healing, as shown in table 1.2

Classification Descriptive terminology Desired clinical outcome
Type 1 Immediate placement An extraction socket with no
healing of bone or soft tissues
Type 2 Early placement – with soft
tissue healing (4-8 weeks post tooth extraction)
A post-extraction site with
healed soft tissues but without significant bone healing
Type 3 Early placement – with partial
bone healing (12-16 weeks post tooth extraction)
A post-extraction site with
healed soft tissues and with significant bone healing
Type 4 Late Placement (more than 6
months of healing post tooth extraction.
A fully healed socket

Table 1 – Classification and descriptive terms for timing of implant placement after tooth extraction.1,2



Biological Events:

The events which take place in a healing extraction socket have been identified in human biopsies and animal
histological material.3,4,5,6,7 Five stages of healing have been described.4 First stage shows an initial clot formation as a coagulum of white and red blood cells. The second stage shows this clot being replaced by granulation tissue, at four to five days. Budding capillaries also occur in this stage via endothelial cells. Over days fourteen to sixteen the granulation tissue is replaced by connective tissue consisting of fibroblasts, and collagen fibres, completing stage three. During the fourth stage, calcification of osteoid is present, beginning at the base and periphery.
Trabeculae bone fill occurs by 6 weeks. After days twenty-four to thirty-five complete epithelial closure has occurred and substantial bone fill occurs.4,5,6,7 By week sixteen, bone fill is complete.8

External Dimensional Changes at Extraction Sockets

The dimensional changes that occur immediately post extraction, to the combined soft tissue and osseous contour can not be ignored. Approximately five to seven millimetres of horizontal ridge reduction occurs within the first six months, which results in a fifty percent reduction from the initial ridge width.3,9,10 Similarly, vertical reductions of two to four and a half millimetres also occur.11,12 Greater vertical changes occur when multiple adjacent extraction sites are compared with single tooth extraction sites.7,12 Bone changes alone can be between three to six millimetres in a buccolingual direction.7,13,14 As such, in order to minimise surgical procedures, patient satisfaction and potentially reducing the amount of bone loss which occurs post extraction, the early intervention implant placement protocols arose. In this discussion we will discuss the advantages and disadvantages of the different implant placement timing protocols.




In conclusion, immediate (Type 1), Early (Type 2 and Type 3), and delayed placement (Type 4) each carry similar healing and success rates. Further to this, a randomised control trial comparing immediate and early placement, in the aesthetic zone, concluded that ‘immediate implant placement is a viable alternative to early implant placement if completed by an experienced surgeon’.31 Each clinical case must be assessed on its merits. Comprehensive examination beginning with medical history and finishing with radiographical analysis and measuring ones clinical experience should dictate the decision of timing of implant placement.




  1. Hämmerle CH, Chen ST, Wilson Jr TG. Consensus statements and recommended clinical procedures regarding the placement of implants in extraction sockets. Int J Oral Maxillofac Implants. 2004 Jan 1;19(Suppl):26-8.
  2. Chen ST, Buser D. Clinical and esthetic outcomes of implants placed in postextraction sites. International journal of oral & maxillofacial implants. 2009 Oct 2;24.
  3. Chen ST, Wilson Jr TG, Hammerle CH. Immediate or early placement of implants following tooth extraction: review of biologic basis, clinical procedures, and outcomes. Int J Oral Maxillofac Implants. 2004 Jan 1;19(Suppl):12-25.
  4. Amler MH. The time sequence of tissue regeneration in human extraction wounds. Oral Surgery, Oral Medicine, Oral Pathology. 1969 Mar 1;27(3):309-18.
  5. Amler MH. Histological and histochemical investigation of human alveolar socket healing in undisturbed extraction wounds. J. Am. Dent. Assoc.. 1960;61:32-44.
  6. Boyne PJ. Osseous repair of the postextraction alveolus in man. Oral Surgery, Oral Medicine, Oral Pathology. 1966 Jun 1;21(6):805-13.
  7. Schropp L, Wenzel A, Kostopoulos L, Karring T. Bone healing and soft tissue contour changes following single-tooth extraction: a clinical and radiographic 12-month prospective study. International Journal of Periodontics & Restorative Dentistry. 2003 Aug 1;23(4).
  8. Evian CI, Rosenberg ES, Coslet JG, Corn H. The osteogenic activity of bone removed from healing extraction sockets in humans. Journal of Periodontology. 1982 Feb;53(2):81-5.
  9. Johnson K. A study of the dimensional changes occurring in the maxilla after tooth extraction.—part I. Normal healing. Australian Dental Journal. 1963 Oct;8(5):428-33.
  10. Johnson K. A study of the dimensional changes occurring in the maxilla following tooth extraction. Australian Dental Journal. 1969 Aug;14(4):241-4.
  11. Iasella JM, Greenwell H, Miller RL, Hill M, Drisko C, Bohra AA, Scheetz JP. Ridge preservation with freeze‐dried bone allograft and a collagen membrane compared to extraction alone for implant site development: a clinical and histologic study in humans. Journal of periodontology. 2003 Jul;74(7):990-9.
  12. Lam RV. Contour changes of the alveolar processes following extractions. Journal of Prosthetic Dentistry. 1960 Jan 1;10(1):25-32.
  13. Lekovic V, Kenney EB, Weinlaender M, Han T, Klokkevold P, Nedic M, Orsini M. A bone regenerative approach to alveolar ridge maintenance following tooth extraction. Report of 10 cases. Journal of periodontology. 1997 Jun;68(6):563-70.
  14. Lekovic V, Camargo PM, Klokkevold PR, Weinlaender M, Kenney EB, Dimitrijevic B, Nedic M. Preservation of alveolar bone in extraction sockets using bioabsorbable membranes. Journal of periodontology. 1998 Sep;69(9):1044-9.