Determination of Peri-implant Mucosal Phenotype

The term periodontal biotype was introduced by Seibert and Lindhe.¹⁸ As per their classification, the gingiva may be categorized into “thick-flat” or “thin-scalloped” biotypes and is currently referred to as “periodontal/peri-implant phenotype”.¹⁸ When the peri-implant mucosal thickness is 2mm or more, it is classified as a thick peri-implant mucosal phenotype whereas a mucosal thickness of 1.5mm or less is characterized as a thin phenotype.¹⁸ The thick peri-implant mucosal phenotype is characterized by the presence of a wide band of keratinized tissue, flat bony architecture, thick marginal bone, broad contact areas, and square-shaped anatomic crowns.^13,18 The thin peri-implant mucosal phenotype is characterized by a narrow zone of keratinized tissue, pronounced scalloping of the tissue, thin marginal bone, narrow proximal contact areas, triangular crown morphology, and reduced quantity and quality of keratinized tissues.¹⁸ A site with a thin peri-implant mucosal phenotype has an increased risk of marginal and papillary recession and bony dehiscence and fenestration. Therefore, such tissues must be handled carefully during surgery, making of impressions, and restorative procedures.¹³ Surgical implant placement in thin phenotype patients should be performed more palatally, and slightly deeper to mask the visibility of titanium and facilitate the development of a proper emergence profile.¹³ Further, phenotype modification procedures must be considered to enhance implant soft tissue stability and esthetics.¹⁹