Peri‑Implant Soft‑Tissue Integration and Management. Mario RoccuzzoЧитать онлайн книгу.
5g The pedicle was adapted with a 4-0 Vicryl vertical mattress suture between the 2 implants.
Fig 5h Final suture, distally to the distal implant.
Fig 5i Preoperative occlusal view.
Fig 5j Postoperative occlusal view.
Fig 5k Periapical radiograph at eighteen months after implant placement. Favorable interproximal bone levels.
Creating an optimal flap for ideal transmucosal healing becomes even more difficult if no keratinized mucosa is present at all. In these circumstances, a free gingival graft may be advised, especially if bone regeneration is required, as discussed in Chapter 4.1.
Often, a small quantity of keratinized tissue will be sufficient to create a soft-tissue cuff around the implant collar, provided the tissue is properly surgically managed. Figures 6a-I show an example of soft-tissue management around a tissue-level implant in conjunction with bone regeneration in a case where there does not appear to be any keratinized tissue available.
Fig 6a Preoperative view of site 46, at the end of orthodontic treatment. Limited crestal width and no keratinized mucosa.
Fig 6b-c Once the implant was placed (S, SLA, diameter 4.1 mm, length 12 mm; Institut Straumann AG), the dehiscence on the facial bone was covered with autologous bone and a DBBM graft.
Fig 6d Resorbable collagen membrane prepared with a punched hole, placed over the graft, and secured with a healing cap.
Fig 6e-f The mesial papilla rotated 90° counterclockwise and sutured to the distal papilla to provide a wide band of keratinized tissue buccally to the implant.
Fig 6g-h e-PTFE sutures, buccal and occlusal views.
Fig 6i Early healing (at six weeks). A new mucogingival line is already evident.
Fig 6j Fifteen months after implant placement, facial view. Ideal contour of the soft tissues thanks to bone grafting and papilla rotation at the time of implant placement.
In many circumstances, poor implant placement may result in restricted access for proper oral hygiene and increase the risk of mucosal inflammation. Plaque accumulation at implant sites causes a more pronounced inflammatory response compared to natural teeth (Berglundh and coworkers 2011). Indeed, even though the evidence is limited, there is a strong common perception that properly placed implants do not present biological complications as frequently as poorly placed implants.
Apart from the prosthetically driven position, a wide band of non-mobile, keratinized mucosa, a correct peri-implant sulcus, and a thick tissue phenotype might seem desirable, if not essential, for reducing the incidence of tissue inflammation and long-term complications around implants.
3.2 Soft-Tissue Management Before Implant Placement
On the occasion of the 2017 World Workshop, Hämmerle and Tarnow (2018) reported that a significant amount of controlled prospective studies with medium-size patient samples indicated that thin soft tissue around implants leads to increased peri-implant marginal bone loss compared to thick soft tissue. Most of the data, however, were published by one group of researchers.
Linkevicius and coworkers (2009) placed 46 implants in 19 patients. The implants were divided into two groups related to soft-tissue thickness. At the one-year follow-up, the marginal bone loss at the implants in the thin-tissue group was on the order of 1.5 mm, compared to only 0.3 mm in the thick-tissue group.
In addition, the same investigators analyzed the effects of buccal soft-tissue thickness on marginal bone-level changes in 32 patients. They found a significant correlation between soft-tissue thickness and bone loss, with thin soft-tissue sites presenting more bone loss (0.3 mm versus 0.1 mm) at the one-year follow-up.
That thin soft tissue leads to increased marginal bone loss was confirmed in another recent study (Linkevicius and coworkers 2015). In addition to the thin-tissue and thick-tissue groups, the investigators followed a third group of about 30 patients whose thin soft tissue was augmented by grafting at the time of implant. The resulting bone loss was not different from that in thick soft-tissue group. These findings seem to indicate that adequate soft-tissue thickness benefits the stability of the peri-implant bone levels.
In another study, Puisys and Linkevicius (2015) concluded that, since significantly less bone loss can occur in naturally thick soft tissue than in patients with a thin tissue phenotype, augmenting the tissue could be the way to reduce crestal bone loss.
Based on the observation that significantly less bone loss occurs around implants placed in thick tissue phenotypes compared to thin phenotypes, clinicians may be encouraged to augment thin soft tissue before or during implant placement in order to facilitate crestal bone stability. Figures 7a-i show an example of this treatment approach in the posterior mandible of a 63-year-old woman.
Fig 7a Panoramic radiograph of the edentulous sites 46 and 47. There is barely enough bone available for implant placement above the mandibular canal.
Fig 7b Edentulous area, buccal view. Very shallow vestibule and absence of keratinized mucosa.
Fig 7c Edentulous area, occlusal view. Very thin crest.
Fig 7d Free gingival graft harvested from the palate sutured above a split-thickness flap in the area where the implants are planned.
Fig 7e Graft sutured with 4-0 Vicryl, occlusal view
Fig 7f At three months, a full-thickness flap was raised lingually and buccally for placing