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Author: Dr Prerna Kaushik

Scientific literature states that extraction of indicated teeth for immediate implant placement should be atraumatic, so that the labial cortical plate is preserved. It has been suggested that an immediate placement of implants may avoid the resorption process of the buccal bone plate and maintain the original shape of the ridge. (Davor Hribar 2007) Rotatory movements in mesial and distal direction are indicated. Since immediate implants are being placed more commonly in anterior region the conical roots usually oblige to come out of the sockets with rotatory movements. If immediate implants are being placed in multi rooted teeth, sectioning the roots is advised so that the buccal cortical plate and interdental bone is preserved.

Use of periotomes and powered periotomes, slender tip instruments like periotomes are used to extract teeth as atraumatically as possible. Periotomes are used to severe the attachment of the periodontal ligament to the teeth. This minimizes the role of extraction forceps and elevators in extraction of the teeth. Excessive force application can fracture the buccal cortical plate which makes the area unsuitable for immediate implant placement.

Powered periotomes (PowertomeTM Periotome, WestPort Medical, Inc., Salem, OR.) are being introduced which regulate the amount of force being applied by the periotome. The distance and the force at which the tip will move into the periodontal ligament space is precisely regulated with a microprocessor controlled, solenoid actuator. Manufacturer claims that the chances of fracture of buccal cortical plate are almost negligible. However this powered periotome has not been tested clinically in studies or trials. More extensive resorption occurs and it usually lasts longer when multiple adjacent teeth are removed than after a single tooth extraction. (Ji Young Han 2011)

The initial gingival shrink around the socket is very rapid; occurring within days and is solely due to wound shrinkage. This produces a reduction in height of the interdental papillae and then moves them to the labial aspect. There is also a reduction of the attached gingival zone. All of this happens very quickly especially where there is a loss of bone support. (Len Tolstunov 2007)

Once the tooth is removed, the periodontium blood supply is destroyed as the periodontal membrane is lost and the socket fills with a blood clot. The blood supply in the thin biotype individual is solely dependent upon the mucoperiosteum. Consequently any surgical elevation of the gingiva from the crestal bone will result in a total loss of blood supply to this crestal region. Whereas in the thick biotype, there is potentially additional protection from the endosteal blood supply. (Len Tolstunov 2007) The periodontal fibres (Sharpey’s fibres) insert into the socket lining of the alveolar ridge which is called “bundle bone”. This bundle bone completely resorbs after the extraction of the tooth due

to disuse atrophy as it is no longer stimulated. Thus preserving it by doing an immediate implant becomes necessary. (Jack Hahn 2010) The marked reduction in the height of the buccal bone crest, which is composed almost entirely of bundle bone, is easily affected by the elevation of surgical flaps. Therefore, there have been trials for placing implants into extraction sockets with minimal flap elevation or without the elevation of surgical flaps. (Len Tolstunov 2007) Very thin periodontal biotypes may be associated with narrow lamellar bone structures on the buccal aspect that seem to consist exclusively of bundle bone, consequently thin biotype individuals lose more bone than the thick biotype individuals, who have thicker socket walls with more bone quantity than bundle bone alone. Achieving esthetic success is suggested to be dependent on an ideal three-dimensional implant position, maintenance of an adequate buccal bone over the implant buccal surface, and tissue biotype. (Len Tolstunov 2007)

After the extraction is accomplished, buccal plate fracture, dehiscence or fenestration, in addition to the physiologic post-extraction alveolar bone resorption are common reasons to compromise implant placement later on, not to jeopardize the esthetic predictability. (Jack Hahn 2010) Therefore, if implants were to be placed into such compromised alveolar bone, a previous bone grafting procedure is mandatory or else immediate implant surface exposure will occur and hence further surgical procedures will be needed to cover the implant threads such as simultaneous bone grafting procedure .

A lot of studies discuss variable techniques in dealing with implant surface exposures at the time of implant placement (Immediate Implant Metal Show; IIMS). This problem can be treated by immediate grafting of the site using autogenous or non autognous grafts. Moreover, implant metal show can be witnessed in few months after implant placement as a delayed implant shadow show (DISS) when the labial bone plate becomes thin or dehisced but is still covered with a relatively thin gingival flap. On the other hand, delayed implant actual show (DIAS) is witnessed when tissue loss occurs at both the bone and gingival envelop.

Immediate reconstruction of lost buccal bone plate witnessed upon dental extraction can improve the predictability of implant placement later on. (Mazen Almasri 2013 ) Histometric findings from recent animal studies have revealed that the placement of implants in fresh extraction sockets was associated with marked alterations of the buccal and lingual socket walls, both in terms of height and width. At the buccal bone wall, this vertical reduction averaged 2.6mm at 3 months. (Araujo et al. 2005). When both surgical models (extraction socket versus healed ridges) were compared experimentally, Botticelli et al demonstrated significant differences in mean vertical bone resorption (2.45 versus 0.68mm at 4 months), concluding that the process of bone modelling

and remodelling at an implant placed in a fresh extraction socket differs from the one that occurs following implant installation in an osseous wide defect prepared ridge (Botticelli et al. 2006). One of the possible causes of this different healing behavior may be that following tooth extraction the socket dimensions are greater than the diameter of a conventional implant and consequently,a marginal gap usually occurs between the implant surface and the socket wall. Although some authors have reported that a critical bone–

implant distance (jumping distance) must exist in order to allow undisturbed osseointegration (Caudill & Meffert1991, Gotfredsen et al. 1991, Knox et al. 1991, Akimoto et al. 1999), others have argued that this distance might not be that important if implants with rough surfaces are utilized and an undisturbed blood clot is allowed to heal (Botticelli et al. 2003). It has been observed that most of the buccal crest resorption occurred between 1 and 3 months. (Araujo et al. 2006a).

It is unclear, whether it is the thicker bone wall or the wider gap between the implant surface and the bone wall that is relevant in the prevention of the buccal crest resorption. The larger fraction of bundle bone that occupies the buccal bone of the socket wall, compared with the lingual side (Araujo et al. 2005) and the observed lack of bone resorption at the lingual aspect of the crest in the present experiment, suggests that the crest thickness may play an important role in this respect.

REFERENCES:-
 
  1. Barzilay, I., Graser, G. N., Iranpour, B. & Natiella, J. R. (1991) Immediate implantation of a pure titanium implant into an extraction socket: report of a pilot procedure. International Journal of Oral and Maxillofacial Implants 6, 277–284.
  2. Paolantonio M, Dolci M, Scarano A, d'Archivio D, di Placido G, Tumini V, et al. Immediate implantation in fresh extraction sockets. A controlled clinical and histological study in man. J Periodontol 2001;72:1560–1571.
  3. Michael Sonick, Hard and Soft Tissue Regeneration for Implants in the Esthetic Zone, October 2001 CONTEMPORARY ESTHETICS AND RESTORATIVE PRACTICE
  4. Kan JY, Rungcharassaeng K, Umezu K, Kois JC. Dimensions of peri-implant mucosa: an evaluation of maxillary anterior single implants in humans. J Periodontol 2003;74:557–562.
  5. Araujo, M. G., Sukekava, F.,Wennstrom, J. L. & Lindhe, J. (2005) Ridge alterations following implant placement in fresh extraction sockets: an experimental study in the dog. Journal of Clinical Periodontology 32, 645–652.
  6. Araujo, M. G., Sukekava, F., Wennstrom, J. L. & Lindhe, J. (2006a) Tissue modeling following implant placement in fresh extraction sockets. Clinical Oral Implants Research 17,615–624.
  7. Araujo, M. G., Wennstrom, J. L. & Lindhe, J. (2006b) Modeling of the buccal and lingual bone walls of fresh extraction sites following implant installation. Clinical Oral Implants Research 17, 606–614.
  8. Davor Hribar, Alan Broughton. Aesthetic zone for the single tooth implant, Australasian Dental Practice July/August 2007
  9. Len Tolstunov,Implant Zones Of The Jaws: Implant Location And Related Success Rate Journal of Oral Implantology, Vol. XXXIII/No. Four/2007
  10. Jack Hahn ,The emergency implant: Immediate Extraction Replacement in the Esthetic Zone. International journal of oral implantology and clinical research. Jan-April 2010:1 ;(1) 1-10

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