STABILITA’ DIMENSIONALE DEL TESSUTO OSSEO PERIMPLANTARE E MANTENIMENTO DELLA PAPILLA: STUDIO RETROSPETTIVO

The purpose of this study is the retrospective evaluation of DIB value (peri-implant bone tissue dimensional stability) and Jemt Index (papilla preservation) of 47 IAC (Integrated Abutment Crown) over Bicon implants (Bicon Dental Implant, Boston, MA, USA) inserted in 23 patients between October 2009 and January 2013. MATERIALS AND METHODS: T0 and T1 periapical x-rays performed accordingly to the long cone paralleling technique using a Rinn positioning system and a radiographic template in order to compensate possible distortions have been used in order to evaluate and assess the distance between the implant shoulder and both the first mesial (mDIB) and distal (dDIB) bone contact.(1) Average values for each implant between T1 and T0 have been calculated, while the Jemt Index has been evaluated from photographs taken at T0 and T1.(2) RESULTS: IACs of this study have been monitored for an average period of 24,6 month (6 to 48 months) with a survival percentage of 100%; 85% of IACs involved the restoration of posterior sectors.(3) Within 8 cases we could register excessive plaque accumulation(mPLI 1,4) with colour alteration due to technical failure of the initial composite resin polishing; the composite resin, once properly polished, showed to be less irregular than ceramic material(4). Within 3 cases we experienced the failure of the connection, most likely due to the lack of connection itself for the presence of too much soft tissue: 2 stealth abutment of 2mm diameter within frontal sectors restoration and the third one being a 4.4 restoration with a 2mm diameter standard abutment. In all of the three cases the problem has been solved by cleaning the gingival sulcus with the use of a sulcus reamer and by successfully reactivating the connection. The presence of exudate has been observed in 5 cases; 3 of these cases showed clinical and radiographic evidence of peri-implantitis. Average Jemt index (both distal and mesial) at T0 resulted to be 0 within 3 cases, 1 within 3 cases, 2 within 29 cases, 3 within 11 cases e 4 in 1 case while we assisted a spontaneous regeneration of the papilla in more than 50% of the cases at T1. We could also assess optimal marginal fit with only 5 cases affected by gingival recession; 2 of these cases regarded frontal sector and have been addressed correcting the IAC to the new marginal position while 3 cases were associated with peri-implantitis of the posterior sector. CONCLUSIONS: This study shows how IAC system represents a valuable option for the prosthodontics rehabilitation. Optimal marginal fit, bone tissue stability within the bone ridge and papilla preservation are supported thanks to the particular design of the implant neck (sloping shoulder) the emispherical base design and the taper locking connection; thanks to the precision of the crown, the mechanical stability and performance of the bacterial seal and the construction of an individualized profile we are able to realize a highly valuable prosthetic restoration with optimal aesthetics, avoiding cement-induced misfit problems and optimizing every operational time.(5)