Alveolar Ridge Preservation

14 April 2025

Picking bones

The alveolar bone is the soil that keeps the teeth planted, but resorption of it occurs frequently in the first six months following a tooth extraction.[i] Implant treatment success relies on minimal alveolar bone loss; the higher the loss the smaller the chance of osseointegration. In this case, the likelihood of the patient having to return for further treatment increases, reducing their trust and confidence in the clinician and costing them time and resources.

To overcome the challenge of alveolar bone loss management, filling the extraction socket with biomaterials reduces resorption, ensuring that there will be sufficient bone for osseointegration.[ii] The extraction site, with its abundant blood supply and retention of bone graft material, is a favourable environment for regeneration but, for dental implantologists, there are several biomaterial options to choose from, each with their own benefits or limitations. Determining which one to use is paramount for alveolar ridge preservation (ARP).

 

Autograft repair, autograft replace

Autografts are considered the gold standard for balancing osteoconduction, osteoinduction and osteogenicity.[iii] The gold-standard option, with an 89% acceptance rate,[iv] autogenous bone has the highest bone regeneration capacity due to its natural match with the patient’s anatomy, greatly reducing the risk of rejection and disease transmission.[v] An autograft may be more preferable for patients because of these advantages, as well as the lower cost compared to its alternatives. However, the amount of available autogenous bone to harvest may be limited and a second site is needed, potentially leading to complications such as pain, scarring, infection and limited function. As more procedures are required than for an allograft, patients may not want the risk of further damage with an autograft.

 

Animal bones

With an allograft, patients receive sterilised bone tissue from a donor. Patients may prefer an allograft as it doesn’t require a second surgical site; those in active jobs may wish to minimise pain and speed up recovery, but clinicians should highlight that the match may not be as ideal as an autograft.

Not all donors need to be human: a xenograft uses bovine bones that have been deproteinated and crushed into granules.[vi] Despite the difference in bone source, research has shown that resorption rates are very similar between xenografts and allografts. Xenografts had an average bone loss on the horizontal ridge of 1.47mm and at the mid-buccal and mid-lingual points this was 0.68mm and 0.65mm. In contrast, the allograft average was 1.52mm, 0.68mm and 0.4mm respectively.[vii] For context, resorption measurements without any intervention averaged 3.1mm, 1.79mm and 1.53mm, emphasising the necessity for bone graft materials.[viii]

 

Synthetics

Alloplasts, along with xenografts, have the lowest survival rates after 7 months but have later demonstrated higher survival rates, making them less predictable.[ix] Synthetic materials such as hydroxyapatite and calcium phosphate provide strength and stability to the extraction site and mixing blood has also been noted as a good osteoconductive scaffold to reinforce the fibrous tissue.[x] Without the risk of disease transmission or donor site morbidity and with the advantage of readily available materials, alloplasts can be an efficient and agreeable option for patients, even if they offer weaker regenerative abilities. For patients less at-risk of resorption, an alloplast could be ideal.

 

Complications to consider

To further aid with material selection, there are many risk factors to be aware of. These include:

• Extent of the traumatic injury during extraction
• Socket morphology
• Presence of infection
• If the patient smokes
• Tooth type and position
• Patient compliance
• Medical conditions[xi]

In cases of the latter, a xenograft may not be suitable for patients with weaker or compromised immune systems as there is a higher risk of peri-implantitis.[xii] Compliance is also vital; clinicians must make sure that their implant patients are consistent in their daily oral hygiene routine, paying close attention to the implant site. As 2.8-9.1% of bone graft cases can lead to infection, reducing the risk is crucial for long-term success.[xiii]

 

Staying informed

Keeping up-to-date on the latest developments relating to bone grafting materials is essential for giving the best implant treatments to your patients. By joining the Association of Dental Implantology (ADI), members can access a wealth of educational resources and CPD events, such as the illuminating Study Clubs that occur across the UK. Led by renowned experts, each session discusses recent advancements in the implantology field, whilst also connecting like-minded professionals to improve the way implants are delivered in the UK.

Every decision in the implant process has short and long-term impacts. With bone graft material selection, both clinician and patient should feel empowered in their choice by having a comprehensive understanding of their benefits, knowing the best option to heighten the success of the treatment.

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