An implant over denture system (1) fixes an implant over denture (3) to a residual ridge (8) by means of an implant (10). The implant over denture (3) has a prosthetic tooth (31), a denture baseplate (32), and a magnet structure (4). The implant (10) has an implant main body section (11) and a keeper (2). The maximum diameter (d1) of the circumscribed circle of the external shape of the adsorbed surface of the keeper (2) is set to be at least [phi] 1.8 mm and the maximum diameter (d2) of the implant main body section (11) is set to be at least [phi] 1.2 mm and no more than [phi] 3.5 mm, so that the two diameters have a relationship of d1/d2<；= 1.5.人工植體覆蓋式義齒系統(1)，是用以藉由人工植體(10)將人工植體覆蓋式義齒(3)固定於顎堤(8)。人工植體覆蓋式義齒(3)，具有：人工齒(31)、義齒齒床(32)、以及磁石構造體(4)。人工植體(10)，具有：人工植體本體部(11)、以及保持件(2)。位在保持件(2)之被吸附面之外形上的外接圓，其最大直徑d1是設定為 1.8mm以上，人工植體本體部(11)的最大直徑d2是設定為 1.2mm以上且 3.5mm以下，並且具有d1/d2≦1.5的關係。
