Esthetic improvement in clinical scenarios of suboptimal implant placement can also be achieved by means of a pediculated connective tissue graft. The existing crown and abutment are removed, and the soft tissue is allowed to naturally “self-cover.” Approximately 3 months later, the implant is exposed, followed by placement of a 2-mm-tall healing abutment. A pediculated connective tissue graft is rotated from the palate, then flipped over the implant/healing abutment and secured with sutures. The second-stage surgery is performed in 4 months, followed by restorative procedures. This technique is able to increase the volume of soft tissue, resolving the initial esthetic complications.127
Acellular dermal matrix grafting in conjunction with coronally advanced peri-implant tissue has also been shown to improve implant esthetics. This technique was reported in a patient presenting with deficient esthetics, thin peri-implant tissue, and 3 mm of recession. Results of the case showed great esthetic improvement with partial coverage, thicker peri-implant tissue, no bleeding on probing, and no significant probing depths. This procedure demonstrated an alternative to harvesting tissue from the patient’s palate.128
Integrity and thickness of facial bone
The presence and volume of bone is one of the most critical anatomical factors to be considered for achieving an esthetic outcome. Once the implant is positioned, a circumferential moatlike bone remodeling of approximately 1.4-mm width occurs.147 At least 2 mm of buccal bone thickness is proposed to avoid loss of buccal crestal bone in a vertical direction. Moreover, additional bone grafting around implant sites with dehiscence or inadequate bone volume is strongly recommended. A lack of bone volume may jeopardize the esthetic outcome due to considerable risk of soft tissue recession.140
Evidence indicates that the placement of bone graft material in the gap between the implant surface and facial bone has positive effects in animal and human studies. The bone graft can counteract, or at least reduce, the inevitable bone remodeling process around implants immediately placed in fresh extraction sockets. When a bone graft of porcine origin was used to fill the gap in test sites with a resorbable membrane covering the entire extraction socket, test sites showed a stable bone level and even some bone gain. Extensive bone remodeling was observed in the control sites.148 In a similar study comparing immediate implant sites with and without placement of xenogeneic graft material, the test sites (with bone graft) had (1) a peri-implant bone level located 1 mm more coronally, (2) thicker facial tissue (1 ± 0.3 mm versus 0.4 ± 0.4 mm), (3) facial bone located more coronally on the implant (0.1 ± 0.5 mm versus 1.3 ± 0.7 mm), and (4) thicker facial bone (1.1 ± 0.5 mm versus 0.1 ± 0.2 mm at 1 mm apical to the implant platform).149
In a case series with 10 patients, a “trimodal” approach (immediate implant placement, flapless approach, and immediate provisionalization) was employed. Xenograft was placed in the gap between the facial bone and the implant surface, and a subepithelial connective tissue graft was interposed onto the facial bone. Favorable implant success and peri-implant tissue were achieved with a mean marginal bone and facial free gingival level change of +0.10 mm and –0.05 mm, respectively. The authors concluded that the facial free gingival margin could be maintained without any further recession when immediate implants are treated with a subepithelial connective tissue graft, ideal three-dimensional positioning of the implant, and the use of graft material to fill the gap between the facial bone and the implant surface.150 Therefore, placement of bone graft material in the gap can be beneficial in minimizing the bone remodeling process, resulting in more favorable hard and soft tissue status around the implant.151
Immediate implants have a similar survival and success rate compared with implants placed into healed sites. The advantages of immediate placement include decreased treatment time, a reduction in the number of surgical interventions, and the potential for immediate provisionalization. This may allow preservation of existing soft tissue and osseous architecture.152–154 When clinicians are considering immediate implant placement in patients with a thin phenotype, careful and detailed evaluation of both the soft tissue and the underlying bony architecture should be carried out. In certain cases, a delayed approach may be the most appropriate treatment when very thin tissue or bone is present. When the possibility of significant recession is expected, hard and soft tissue augmentation should precede implant placement.93 It should be assumed that thin facial bone is present.
Minimally invasive or flapless surgery may be possible and selected as a means to minimize disruption of blood supply to the surrounding hard and soft tissue components. Once the implant is positioned toward the palatal aspect, bone graft is used to fill the gap between the facial bone and implant surface. Where a flap must be elevated to assess structures and surgical landmarks, a subepithelial connective tissue graft should be harvested from the palate and secured over the facial bone. If an implant-supported provisional restoration is provided, it should initially have a concave subgingival profile on the facial aspect to reduce the risk of apical migration of the free gingival margin.104,155
Preserving thin facial bone plates
The mean thickness of facial bone for the maxillary anterior teeth (from canine to canine) is about 0.8 mm, with 87% of sites having a facial bone thickness ≤ 1.0 mm. Measurement of the facial bone thickness of anterior teeth in the maxilla by means of CBCT scans showed that the majority of all teeth examined had ≤ 1.0 mm of bone thickness. Nearly 50% of sites had bone thickness that was ≤ 0.5 mm. Most extraction sites in the maxilla will therefore experience extensive ridge alteration, demanding additional grafting procedures to achieve a minimal width of bone. At least 1 to 2 mm of buccal bone is required for stability of hard and soft tissues.140,156,157
Vertical bone loss is marked after immediate implant placement. A mean vertical bone loss of 0.7 to 1.3 mm on the facial and lingual aspects and a 0.4-mm reduction in the thickness of facial bone at the time of abutment connection can be expected. An exaggerated pattern of vertical bone remodeling around immediate implants was confirmed in an animal study.148 Reference measurements were made from the implant platform to the bone crest and to the bone contacting the implant within the remodeling zone. The distance between the abutment-implant junction and the first bone-to-implant contact was 4.11 ± 1.9 mm, and the distance to the crest of bone was 1.23 ± 0.48 mm for immediate implant sites. In comparison, the mean distances were 2.02 ±0.78 mm and 0.46 ± 0.51 mm, respectively, for the delayed implant sites.158
Tissue effects of tooth extraction
Tooth extractions performed on patients with thick flat gingival architecture may result in minimal dimensional changes to the surrounding gingiva and bone. Extractions performed on patients with thin scalloped gingival architecture, associated with thin bone, dehiscences, and fenestrations, may result in obvious dimensional tissue changes causing significant esthetic concerns.159 For patients with a thin periodontium, atraumatic and very precise surgical techniques should be applied during the extraction to minimize adverse effects on the bone remodeling process.93,160 Ideally, minimal flap elevation or a flapless approach should be used to limit the disruption of blood supply. An animal study compared tooth extraction with and without flap elevation and its effect on the bone remodeling process. The results demonstrated significantly less bone resorption for the flapless group than the flapped group.160 Atraumatic extraction can be accomplished with controlled and steady application of forces on the interproximal areas, limiting any leveraging forces on the thin facial bone. Sectioning of the roots, careful use of periotomes to luxate and expand the periodontal ligament space, and use of controlled extraction devices can also assist in facilitating a satisfactory outcome with minimal hard and soft tissue complications.93 Controlled extraction devices are mechanical devices that lift from a special post placed in the root canal of a crownless tooth. Adjacent teeth support them while they smoothly apply vertical extraction forces.
Ridge preservation procedures
Once the tooth is removed, it is critical to limit the bone remodeling process, especially in patients with