Immediate management of the single-unit extracted tooth in the anterior aesthetic zone – temporizing/stabilizing tissues

Pre-operative management of the extraction socket

Although dimensional change of the alveolar ridge is unavoidable following extraction, the impact on subsequent restoration can be reduced if appropriate pre-operative assessment and management is undertaken.

The pre-operative history should account for risks associated with general patient factors such as medical conditions, periodontal status, past dental treatments, compliance with oral hygiene and patient aspirations. Smoking habits and medical conditions, that include pregnancy, uncontrolled diabetes, intra-venous bisphosphonates and cranial radiotherapy, require careful consideration, as these factors may modify healing or act as a relative contra-indication for some restorative options, such as dental implants.

The soft tissue examination should record the presence of a high lip line, thin gingival biotype, high fraenal attachments and a narrow band of keratinized mucosa (KM), as these factors have the potential to influence treatment. The tissues should also be evaluated for the presence of inflammation or a draining sinus, indicating the presence of suppurating infection or cystic involvement. The presence of existing bone loss at the extraction site should be accounted for by recording a 6-point-pocket charting (to determine bone loss from periodontal disease). Radiographic assessment should note features such as horizontal bone levels and apical bone status.

Teeth with intra-radicular infection and extensive periapical bone loss or suppuration may require endodontic treatment as a pre-extraction measure, to reduce the bacterial load and reduce the post-extraction dimensional change. Debridement of the socket would also facilitate physiological healing at the extraction site. A range of clinical approaches can then be adopted to manage the extraction socket (Table 2) and the clinician and patient should jointly decide on the preferred approach.

Intra-operative management of the extraction socket

The adoption of an atraumatic extraction technique, including the use of periotomes to cut the periodontal ligament and bone removal with piezoelectrical surgical units (Figure 2), requires greater operator skill and more clinical time than conventional extraction techniques. However, these negatives should be weighted against the perceived benefits of atraumatic extraction that include, reduced damage to the socket wall and a reduction in tissue resorption during healing. The use of luxators may be a useful compromise.

Alveolar ridge preservation (ARP) techniques, at the time of extraction, show great promise in promoting healing and retaining both alveolar and gingival tissue. ARP techniques include socket grafting, guided bone regeneration (GBR) and socket seal (Figure 3).

A wide variety of products can be used to undertake ARP and include: autogenous bone allograft,⁴ deproteinized bovine or equine bone^5,6 alloplastic polymers,⁷ bioactive glasses⁴ and composite ceramic materials.⁶ Although bone substitutes maintain tissue contour in extraction sites, the operator can still expect some reduction in both the buccal bone height (approximately 0.74 mm) and width (1.2 mm).³

Soft tissue grafting may also assist with the establishment of a stable keratinized mucosal margin, aiding in the provision of conventional or implant-supported prostheses.^8,9

Although ARP techniques can be used to aid in the restoration of extraction sites with dentures or bridges, they are perhaps most pertinent in the replacement of a tooth with a dental implant. Dental implant success is principally associated with stable integration of the fixture into the bone and establishment of a healthy gingival tissue.¹⁰ Using ARP to minimize alveolar and soft tissue changes and reconstitute the morphology of the bone may optimize the site for delayed dental implant placement (Figure 4). In addition, the establishment of a stable band of peri-implant keratinized mucosa reduces the risk of recession and implant mucositis,^11,12 whilst aiding aesthetics of the prosthetic tooth by emulating a natural emergence profile and papilla structure. However, it should be recognized that no difference has been shown between success rates for implants placed in ARP sites, with limited evidence to promote the superiority of individual ARP techniques.¹³

Restorative management of the extraction socket: prosthetic replacement of the tooth

The following principles offer guidance for the immediate prosthetic management of the extraction socket:

An immediate prosthetic replacement of the anterior tooth is normally required for the replacement of an anterior tooth, with this structure having a key role in promoting healing. The immediate prosthesis should, as a minimum, neither disrupt nor impair tissue repair or remodelling whilst providing an aesthetic replacement. The immediate replacement can be undertaken by removable or fixed prosthetic structures. Removable restorative appliances may involve the use of conventional acrylic partial dentures (RPD) or vacuum-formed retainers with an acrylic/composite tooth added. Compression of the mucosal alveolar ridge, through vertical pressure, may be minimized by:

Although a flangeless RPD is preferred, this can often result in an unsightly gap below the pontic tooth as the tissue remodels. The provision of a small flange (lying slightly apical to the gingival margin) will reduce compression of the tissues whilst also allowing chairside reline of the RPD (and elimination of the sub-pontic space) to be undertaken. Removable appliances are prone to plaque accumulation and subsequent gingival inflammation; care should be taken to limit the gingival marginal extension of appliances and the patient should also be given detailed instruction on appropriate use and hygiene of the prosthesis.

Fixed restorative options may avoid many of the limitations incurred with removable prostheses and include the use of resin-bonded bridges (RBB), provisional fixed bridgework or dental implants. RBBs can be pre-prepared with a porcelain/composite pontic or as a plain metal framework that requires the crown of the extracted tooth to be sectioned from the root and used as the pontic on the framework. These pontics can be extended apically by 3–4 mm below the amelo-cementum junction to allow socket fit with the aim of developing a natural soft tissue emergence profile (Figure 6).¹⁴ Resin meshes (ie Everstik^®) combined with composite offer a convenient means of retaining the sectioned crown to adjacent teeth.

Restorative management of the extraction socket: immediate dental implant placement

Immediate dental implant placement can be defined as a surgical procedure where the implant fixture is placed immediately or within one week of tooth extraction. Although survival outcomes for immediate implant placement are excellent and in keeping with conventionally-timed techniques,⁸ poorer results are reported with regards to their aesthetic success.¹⁵ It is recognized that immediate dental implant placement does not prevent resorption of the bundle and alveolar bone¹⁶ and there lies potential for unfavourable bone loss and mucosal recession. The European Association for Osseointegration (EAO) has recommended criteria for immediate dental implant placement to include:

A variety of immediate implant placement approaches have been advocated to overcome the challenges presented by adverse bone and soft tissue remodelling. Minimally traumatic (flapless)¹⁸ implant placement (Figure 7) has been studied less than conventional (raising of a flap) approaches but aims to reduce labial bone resorption by maintenance of the blood supply from a minimally-disturbed labial periosteum. Raising a flap facilitates guided bone augmentation, using either autogenous and/or xenogenic bone products with a protective membrane, and has been demonstrated to be effective in achieving longer-term aesthetic results.^19,20,21 Thin soft tissues may also be augmented with connective tissue harvested from the hard palate,²² xenogenic (eg Mucograft^®)²³ or allogenic materials (eg Alloderm^®).

Implant placement can also be delayed by 6–12 weeks (to account for the majority of socket resorption and remodelling) and the establishment of a continuous gingival soft tissue layer. The continuity of the gingival tissue will assist in GBR reconstruction of the labial alveolar bone over the implant. Considerations on timing, and GBR requirements, for dental implant placement include (Table 4):

Independent of the surgical approach adopted, strict implant placement criteria must be applied.²⁴ The implant should be placed 3–5 mm beyond the apical extent of the socket and aim to engage as much of the palatal plate as possible to provide primary stability. Care is required to ensure that the implant emerges within an envelope of angulation that provides sufficient depth of labial mucosa to prevent shine through of the abutment collar and facilitate simple restoration. The depth of placement must also be sufficient to provide both prosthetic adaptation of a papilla, considered to be 5 mm from the crest to the contact point of the crown,²⁵ and space for the development of the emergence profile of the crown. A surgical guide stent, appropriately outlining the proposed crown, can offer the surgeon valuable information as to the correct depth to place the implant (Figure 8). Alternatively, a fully guided approach can be adopted using a CADCAM prepared stereolithographic stent.

Further consideration must be given to whether to load the implant conventionally, generally 3–4 months post-insertion, or to restore the dental implant immediately. Although there is little difference with regards implant survival,²⁶ a trend for increased crestal bone loss has been found with immediately-loaded implants. Success with immediately restored implant survival may relate to factors such as primary stability of the implant, the implant's resistance to movement during function and maintaining occlusal micromotion loading forces within a tolerance range of 50–150 μm. To reduce possible complications with immediately loading, the clinician should apply appropriate selection criteria; mirroring those previously described for flapless surgery. The clinician must also ensure that the implant crown complies with the following:

Patients with clenching or bruxism habits require particular care to ensure that these parafunctional forces are not translated to the crown. Immediate loading should be avoided in clinical situations where these forces cannot be controlled, such as in the depleted dentition.

In the absence of a strong evidence base, operator preference and patient factors are likely to dictate on the treatment option selected. For example, the total treatment time, number of procedures involved and a cost/benefit analysis will influence this patient decision.²⁷ All treatment aims for the best possible outcome. Implant dentists are more critical of their work than their patients, who remain, in general, highly satisfied with the implant work provided under current protocols even if there is some aesthetic compromise.²⁸

Summary