Alveolar bone remodelling follows tooth extraction and traumatic extraction is associated with additional bone loss. Prior to extraction periodontal disease, periapical pathology and mechanical trauma can also lead to loss of bone. In order to maintain a good alveolar ridge a range for preservation procedures have been investigated. The aim of this review was to investigate the effect of ridge preservation on the residual alveolar ridge dimensions and on histological characteristics, compared to unassisted socket healing.

The review was conducted according to a protocol based on Cochrane collaboration guidelines with searches being conducted in Medline; Embase, Cochrane Central Register of Controlled Trials (CENTRAL) and Lilacs databases supplements by hand searches if a number of relevant journals. Only randomised controlled trials (RCT), controlled clinical trials (CCT) and prospective cohort studies conducted in humans were included and no language restrictions were applied. The primary outcome considered was the change in oro-facial (horizontal) and apico-coronal (vertical) alveolar ridge dimensions.

• Eight RCTs and six CCTs were identified. Clinical heterogeneity did not allow for meta-analysis.
• Average change in clinical alveolar ridge (AR) width varied between −1.0 and −3.5±2.7 mm in alveolar ridge preservation (ARP) groups and between −2.5 and −4.6±0.3 mm in the controls, resulting in statistically significantly smaller reduction in the ARP groups in five out of seven studies.
• Mean change in clinical AR height varied between +1.3±2.0 and −0.7±1.4 mm in the ARP groups and  between −0.8±1.6 and −3.6±1.5 mm in the controls. Height reduction in the ARP groups was statistically significantly less in six out of eight studies.
• Histological analysis indicated various degrees of new bone formation in both groups Some grafts interfered with the healing.
• Two out of eight studies reported statistically significantly more trabecular bone formation in the ARP group.
•  No superiority of one technique for ARP could be identified; however, in certain cases guided bone regeneration was most effective.
•  Statistically, significantly less augmentation at implant placement was needed in the ARP group in three out of four studies.
•  The strength of evidence was moderate to low.

The authors concluded

Post-extraction resorption of the AR might be limited, but cannot be eliminated by ARP, which at histological level does not always promote new bone formation. RCTs with unassisted socket healing and implant placement in the ARP studies are needed to support clinical decision making.

Comment

This is a well-conducted systematic review which provides a detailed summary and discussion of the evidence available for ARP. It also raises a number of questions which need to be answered before ARP techniques are widely recommended. For, although there is some evidence of benefit, the authors highlight the fact that the strength of the available evidence ranges from weak to moderate so, the conclusions of this review should be interpreted with caution.   A number of other reviews related to this topic are available (see links).

Links

Horváth A, Mardas N, Mezzomo LA, Needleman IG, Donos N. Alveolar ridge  preservation. A systematic review. Clin Oral Investig. 2012 Jul 20. [Epub ahead of print] PubMed PMID: 22814758.

Morjaria KR, Wilson R, Palmer RM. Bone Healing after Tooth Extraction with or without an Intervention: A Systematic Review of Randomized Controlled Trials. Clin Implant Dent Relat Res. 2012 Mar 8. doi: 10.1111/j.1708-8208.2012.00450.x. [Epub ahead of print] PubMed PMID: 22405099

Vignoletti F, Matesanz P, Rodrigo D, Figuero E, Martin C, Sanz M. Surgical protocols for ridge preservation after tooth extraction. A systematic review. Clin Oral Implants Res. 2012 Feb;23 Suppl 5:22-38. doi:  10.1111/j.1600-0501.2011.02331.x. Review. PubMed PMID: 22211304.

Ten Heggeler JM, Slot DE, Van der Weijden GA. Effect of socket preservation  therapies following tooth extraction in non-molar regions in humans: a systematic review. Clin Oral Implants Res. 2011 Aug;22(8):779-88. doi:10.1111/j.1600-0501.2010.02064.x. Epub 2010 Nov 22. Review. PubMed PMID:21091540.

Tan WL, Wong TL, Wong MC, Lang NP. A systematic review of post-extractional  alveolar hard and soft tissue dimensional changes in humans. Clin Oral Implants Res. 2012 Feb;23 Suppl 5:1-21. doi: 10.1111/j.1600-0501.2011.02375.x. Review. PubMed PMID: 22211303.  ( see Dental Elf  3 April 2012)