Abstract
To ensure that patients are satisfied with the esthetic outcomes of implant treatment， it is not only essential to restore
the crown of the tooth but also to ensure that the peripheral gingiva and interdental papillae are well positioned for long-term
stability． To achieve these goals， it is important to secure sufficient bone （hard tissue） and soft tissue at the implant site．
Although there are individual differences， it is generally accepted that if the implant and abutment have the same diameter， at
least 2 mm of bone must be secured on the buccolingual （labiopalatine） side of the implant， or at least 1.5 mm in the case of
platform switching， with at least 1.5 mm between the implant and natural teeth and at least ３ mm between two implants，
depending on the design that is used． As it is thought that peri-implant soft tissue must be around ４ mm in height， many
authorities suggest that if the implant and abutment have the same diameter the implant insertion depth must be around ３
mm deeper than the peripheral gingiva in the apical direction， and around ４ mm deeper if platform switching is used． The
required thickness of buccolingual （labiopalatine） soft tissue is believed to be around 2 mm． The shape of the superstructure is
concave below the gingival margin to secure the required thickness of buccolingual （labiopalatine） soft tissue， and the half-pon-
tic technique can be used for the abutment shape using the same method as for tooth restoration．
