A number of systematic reviews have reported that immediate implant placement is associated with a significant risk of soft-tissue recession.1-3 Furthermore, if the facial bone resorbs, there is a risk of biofilm contamination of the exposed implant surface and subsequent inflammation of the peri-implant mucosa.
The extent of the resorption of the facial bone is dependent on the thickness of the facial bone.4 If the facial bone is thin (< 1 mm), it resorbs three times more than if the facial bone is thick (≥ 1 mm).5 Thus, clinicians should identify thick bone phenotypes to reduce the risk of mucosal recession and increase the chances of successful bone regeneration in the marginal peri-implant defect.
Clinical diagnostic measures
The ideal situation for placing an immediate implant is when the soft tissue phenotype is thick with no gingival recession, the facial bone of the socket is both thick and intact, there is absence of acute infection and there is sufficient bone apical to the socket for implant stability.6
The first step is the clinical examination. The patient needs to be periodontally healthy with sufficient plaque control and motivated to maintain oral health. If the gingiva is inflamed, implant treatment should be deferred until inflammation is controlled and the patient is performing oral hygiene at the required level.
At the proposed implant site, the soft tissues can be evaluated by visual inspection and the use of a periodontal probe. Thick gingiva can usually be determined by simply looking at the soft tissues. Another way of looking at the soft tissue thickness is with a periodontal probe placed into the gingival sulcus.7 If the metal of the probe is not visible through the soft tissues, then the gingiva can be regarded as thick.
In relation to the condition of the facial bone wall, careful probing with a periodontal probe will determine whether the bone wall is intact or not. With intact bone, probing pockets should be shallow, ranging from 1 to 3 mm. If there are deep pockets present, this indicates damage to the facial bone and the presence of a dehiscence defect.
The clinician should also look for draining fistulae, which would indicate active periapical pathology and a fenestration of the facial bone. The history of the tooth can also provide clues as to the condition of the facial bone. If an apicectomy has been performed, then there is a good chance that part of the facial bone is missing in the region of the apicoectomy. Plain film radiography (periapical or panoramic radiograph) is an important diagnostic tool to determine the presence or absence of apical pathology and whether there is likely to be sufficient bone to stabilize the implant.
Today, cone-beam computed tomography (CBCT) provides a convenient way of obtaining 3-D images for implant treatment planning. Depending upon the site, the lips and/or cheeks should be retracted with plastic retractors or cotton wool rolls. This creates an air space between the lips and cheeks and the alveolar process that can help provide a clear view of the facial bone and gingiva.8 The thickness of both the facial bone and soft tissues can be determined with this approach. Additionally, the presence or absence of apical pathology can be confirmed once again and the apical bone assessed to ensure that an implant can be placed in the correct 3-D position with stability.
See article “Immediate implant placement - Handling” for more details on the treatment itself.