Interview: Understanding the timing of post-extraction implant placement
On 16 September, Osstell will be holding its ISQ Online Symposium, presenting four scientific sessions and one panel discussion. One of the speakers at the event, which is being held in a digital format for the second time, is Dr Stephen Chen from Australia. In his symposium lecture, he will speak about the case selection criteria for immediate, early and late implant placement for optimal outcomes. Prior to the event, he spoke with Dental Tribune International about post-extraction healing concepts, the right time to place a dental implant after tooth extraction and the importance of proper case selection in order to provide patients with predictable results.
Dr Chen, in your Osstell ISQ Symposium lecture, you will talk about current concepts of post-extraction healing. Which concepts will you discuss in detail?
When a tooth is extracted, healing is characterised by gradual regeneration of bone within the extraction socket. At the same time, the outer cortex undergoes resorption, particularly from the buccal or facial aspect. These wound healing changes lead to a gradual diminution of the dimension of the ridge, which in turn may have an impact upon the subsequent plan to replace the tooth with a dental implant. The dimensional change of the alveolar ridge after extraction takes place in two stages. Initially, there is a rapid resorption of the bundle bone that lines the socket. On the facial aspect, the bundle bone often comprises the entire thickness of the socket wall. The subsequent resorption of the bundle bone leads to a rapid alteration of the dimension of the ridge. Over the longer term, further dimensional change takes place owing to bone modelling. These concepts underpin the recommendations for the timing of implant placement and case selection after tooth extraction.
In how far does the timing of implant placement after extraction play a role in order to obtain a predictable outcome?
There are essentially three time points when implants may be placed after tooth extraction—immediate implant placement, early implant placement and late placement. If an implant is placed at the time of extraction, steps to mitigate the rapid initial resorption need to be undertaken in order to avoid significant bone resorption and soft tissue recession. Immediate implants are generally not recommended in sites with thin bone and soft tissue phenotype or with damage to the facial socket bone wall. Early implant placement takes place during the initial healing phase. Some resorption of the ridge has already taken place, and therefore, implant placement needs to be combined with bone augmentation procedures to compensate for the resorption that has taken place. With late implant placement, the alveolar ridge has fully healed and the dimensional change has regional equilibrium. If there is sufficient available bone for an implant to be placed, the position of the implant is not always ideal, and bone augmentation is required to compensate for the resorption. For this reason, a socket grafting procedure is often recommended if a delay in implant placement post-extraction is anticipated.
You will also talk about new classifications for implant placement and loading time. Could you give our readers an overview of what this will include?
There is a consensus view that, when a decision is made to place an implant to replace the tooth, then both the timing of implant placement after extraction and the subsequent loading protocol should be determined before treatment commences. Therefore, it makes sense to combine the classification for timing of implant placement with the classification for loading protocols. The new classification system is combined with the International Team for Implantology definitions for placement and loading.
You have published a study on primary stability and healing outcomes of apically tapered and straight implants placed into fresh extraction sockets. Implant stability was measured with the help of the implant stability quotient (ISQ) from Osstell. Could you summarise the main findings of your study and explain the role of the ISQ?
In this preclinical study, apically tapered and straight implants were placed immediately into extraction sockets of the maxillary second incisors in a canine model. The primary outcome variable was the ISQ at the time the implants were placed. It was observed that implants with an apical taper demonstrated significantly higher ISQ values than straight implants. This suggests that implants with an apical taper may be preferable to straight implants in single root immediate extraction sockets, particularly if an immediate loading protocol is being considered.
Would you like to add anything else?
As clinicians, we should always adopt a least risk approach, so that we can provide our patients with predictable results that are stable and maintainable long-term. Understanding the advantages and disadvantages of each time point for post-extraction implant placement leads to a clearer understanding of the case selection criteria of each. With proper case selection, complications are minimised, and long-term outcomes are enhanced.
Editorial note: Dr Stephen Chen’s symposium session, titled “Post-extraction implant placement: When immediate, when early and when late”, will be broadcast on 16 September at 9 p.m. CEST. Participants will be able to earn a continuing education credit by answering a questionnaire after the lecture. Dental professionals who would like to attend the presentation may register on the Osstell Campus.