After implant loading and crown insertion, soft tissues around implants may exhibit some deficiencies. These deficiencies may lead to showing a black shadow of the implant body under a thin biotype or may result in gingival recessions. Thin tissues are prone to more recession, are susceptible to attachment loss and gingival displacement over time [51], and lack bone stabilization [52, 53].
Recession is prevalent around natural teeth as well as implants. This prevalence seems to be age related. For patients in their twenties, the rate of recession is about 27.9% [54] and increases to reach up to 100% of the population in their fifties [55]. Gingival recession may be related to traumatic injuries, such as faulty tooth brush- ing, which primarily affects the buccal surface of the maxillary anterior and premo- lar dentition [56]. Gingival recession may also result from an inflammatory reaction to bacteria-related plaque accumulation, which may occur around any tooth in the oral cavity [57].Treating recession, whether around natural dentition or implants, is not guaran- teed to result in complete coverage for the exposed portion of the root or implant fixture. As mentioned before, different gingival grafting techniques have been con- sidered and applied in an attempt to achieve satisfactory results. The stability of soft tissues around implant-supported crowns is essential for long-term optimal aes- thetic outcomes [58]. If recession is left untreated, it will affect the esthetic appear- ance, often negatively reflected in a patient’s self-esteem [59]. Not only will grafting improve aesthetic results, but it will also augment the peri-implant gingival tissues in a way to allow patients to perform proper oral hygiene measures without pain and discomfort.
As defined by the glossary of periodontal terms (3rd edition, American Academy of Periodontology, 1992), recession is the location of the marginal periodontal tis- sues apical to the cemento-enamel junction. Given the morphological differences between periodontal and peri-implant tissues [60] and the related anatomical characteristics, it is reasonable to assume that a grafting procedure is more sophisti- cated around dental implants than natural dentitions. Caution should be practiced during surgical implant placement regarding hard bony structures [61]. A severe buc- cally positioned implant may lead to hard tissue dehiscence, which may negatively influence the peri-implant soft tissue position, leading to gingival recessions [62].
Approximately 24% of immediately placed implants will manifest gingival recession in 1-year follow-up [61]. The next section will discuss the two most com- monly used techniques to correct soft tissue dificiencies around implants.
Autogenous Tissues
The surgeon can either harvest connective tissue or free epithelized gingival tissue grafts (FEGTG). The next section will focus on connective tissue grafts.
Connective Tissue Graft
Accompanied by a coronally positioned flap, the connective tissue graft is con- sidered to be the gold standard technique of gingival tissue augmentation around natural teeth and implants [63], resulting in about 66% coverage at the 6-month follow-up [64]. Figures 4.50, 4.51, 4.52, and 4.53 show the restoration of a sec- ond mandibular premolar implant with a well-fitted crown. Two years later, the buccal side shows that the metal margin of the crown has become exposed due to gingival recession and a lack of adequate soft tissues. In an attempt to increase the zone of healthy thick gingiva and attain metal margin coverage, a gingival graft utilizing autogenous connective tissue was performed. The graft was com- pletely covered under an envelope flap to ensure adequate blood supply. As shown in Fig. 4.54, the procedure resulted in a significant increase in the thick- ness and width of healthy gingival tissues, which will serve to improve esthetic as well as improve longevity.
Free Gingival Graft
The same technique described before in Figs. 4.36, 4.37, and 4.38 can be utilized around restored implants.
Acellular Dermal Matrix Allograft (ADM)
This is a freeze-dried, cell-free, dermal matrix prepared by removing the epidermis and cellular components of human donor skin tissues [41]. The first documentation of the dental use of ADM was in 1996. It can act as a scaffold to allow repopulation of fibroblasts, blood vessels, and epithelium from surrounding tissues [65, 66]. ADM allows some advantages over the use of autogenous gingival tissue grafts: (1) it does not require additional wound of the donor site, (2) it avoids the limitation of autogenous tissues, and (3) Wie PC et al. reported better esthetic outcomes com- pared to autogenous tissues.
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