Alveolar Ridge Preservation/Socket Grafting
In an attempt to attenuate the resorptive events that follow tooth loss and to minimize the need for ancillary ridge augmentation procedures, ARP (also known as socket grafting) is performed immediately following extraction of the tooth. The need for ARP increases when the socket walls are thin or missing after extraction.13 Facial wall thickness of ≤1 mm is a critical factor associated with the extent of bone resorption seen following extraction of single rooted teeth. Thin walled phenotypes in a novel 3d analysis by Chappuis and colleagues14 displayed pronounced vertical resorption with a median bone loss of 7.5 mm, as compared with thick wall phenotypes which decreased by only 1.1 mm.
A variety of bio material and barrier membrane usage in the socket have been shown to successfully help minimize volumetric shrinkage that follows extraction.1 Biomaterials that are commonly used for this purpose include autogenous blood derived products, xenografts (animal derived), allografts (human derived) and alloplasts (synthetic substitutes). Some examples of barrier elements include xenogenic collagenous membranes and autogenous blood products. Depending on the graft material used a healing time of 4-6 months will be required before re-entry for implant placement to allow for adequate vital bone formation and graft integration.15
A recent systematic review critically evaluated the available evidence on the effect of different modalities of alveolar ridge preservation (ARP) as compared to tooth extraction alone. They concluded, based on their systematic review and meta-analysis, that ARP via socket grafting as compared to tooth extraction alone, prevents horizontal (M=1.99 mm; 95% CI 1.54-2.44; p<0.00001), vertical mid buccal (M=1.72 mm; 95% CI 0.96-2.48; p<0.00001) and vertical mid lingual (M=1.16 mm; 95% CI 0.81-1.52; p<0.00001) bone resorption. The application of particulate xenogenic or allogenic materials covered with absorbable collagen membrane or sponge was associated with most favorable outcomes in terms of horizontal ridge preservation.1 A randomized controlled trial by Avila-Ortiz showed that additional bone augmentation to facilitate implant placement in a prosthetically acceptable position was deemed necessary in 48.1% non-grafted extraction sites versus only 11.5% of ARP sites.16 Furthermore, sites that receive ARP exhibit no difference compared with sites that underwent unassisted socket healing in terms of implant loss or success.17