Dental implants anchor into the jawbone through direct contact between the bone and the implant, a process known as “osseointegration.” Recent evidence suggests that the sustained success and survival of implants are not exclusively contingent on “osseointegration” but also on the soft tissues enveloping the transmucosal section of the implant, which serves as a barrier between the peri‐implant bone and the oral cavity (Figure 1.1). This soft tissue seal, often referred to as the “peri‐implant mucosa,” plays a crucial role in the overall health and longevity of dental implants [1]. The attachment of soft tissue to the implant functions as a biological seal, ensuring optimal conditions and thwarting the onset of peri‐implant infections, such as peri‐implant mucositis and peri‐implantitis. Consequently, the peri‐implant soft tissues play a pivotal role in ensuring the long‐term survival of implants [1].

As soft tissue develops around teeth during tooth eruption, it forms a seal that protects the supporting tissues – namely, the alveolar bone, periodontal ligament, and cementum – from exposure to the oral cavity [2]. In contrast, the peri‐implant mucosa is established after the oral soft and hard tissues undergo a healing process to accommodate the osseointegrated implants. The following section provides a concise overview of the key anatomical features of peri‐implant tissues.

Structure of Peri‐implant Tissues in Health

During the process of wound healing following the accommodation of dental implants, the features of the peri‐implant mucosa are established [3] (Figures 1.2–1.4). Berglundh et al. [4] conducted an examination in dogs to investigate the anatomical and histological features of the peri‐implant mucosa formed in a two‐stage procedure, comparing them with the gingiva around teeth.

It was revealed that the peri‐implant mucosa consists of a keratinized oral epithelium located at the external surface. This epithelium is connected to a thin non‐keratinized sulcular epithelium facing the abutment and terminating in junctional epithelium, equivalent to the junctional epithelium around teeth, termed as peri‐implant junctional epithelium. The peri‐implant junctional epithelium terminates 2 mm apical to the coronal soft tissue margin and 1.0–1.5 mm coronal to the peri‐implant bone crest. The mean supracrestal soft tissue, including sulcus depth, measured 3.80 mm around implants and 3.17 mm around teeth (Figures 1.2–1.4).

While no statistically significant difference was observed in the height of the junctional epithelium and sulcus depth between implants and teeth, the height of the soft connective tissue was statistically significantly greater around implants than around teeth. The peri‐implant junctional epithelium and the soft connective tissue adjacent to the abutment appeared to be in direct contact with the implant–abutment surface [4].

In summary, this study demonstrated that the peri‐implant mucosa exhibits comparable anatomical features to those of gingiva around teeth [4].

Subsequent studies provided evidence that a similar mucosal attachment formed on titanium in conjunction with different implant systems [5, 6] and around intentionally non‐submerged and initially submerged implants [7, 8, 9]. However, the peri‐implant junctional epithelium was significantly longer in initially submerged implants to which an abutment was connected later than in intentionally non‐submerged implants [9].

The biologic width (i.e., the supracrestal soft tissue) was revisited in a further dog experiment after abutment connection to the implant fixture with or without a reduced vertical dimension of the oral mucosa (Berglundh and Lindhe [10]). While the peri‐implant junctional epithelium was about 2 mm long, the supra‐alveolar soft connective tissue was about 1.3–1.8 mm high. Interestingly, sites with a reduced mucosal thickness consistently revealed marginal bone resorption, adjusting the width of the supracrestal soft tissue. Evaluating the biologic width around one‐ and two‐piece titanium implants that healed either non‐submerged or submerged in dog mandibles, Hermann et al. [11] suggested that the gingival margin is located more coronally, and the biologic width is more like teeth in association with one‐piece non‐submerged implants compared to either two‐piece non‐submerged or two‐piece submerged implants. These findings were later confirmed in a comparably designed dog study with another implant system [12].