One of the most common problems for cement-retained implant prosthesis is the undetected cement remnants (UCRs) after cementation, in spite of meticulous cleaning around the margin between abutment and restoration. UCRs can cause chronic inflammation around the implant and lead to peri-implant mucositis or peri-implantitis.
Materials and Methods
Sixty patients were involved in this study with 57 single implant supported prostheses and 4 multiple-unit implant supported prostheses. Excess cement was cleaned by trained clinicians and the restorations were removed for evaluation of the UCRs. Gingival surfaces of the all removed restorations were photographed parallel to the abutment screw hole with 1:1.5 magnifications. To analyze the rate of UCRs to abutment area, Adobe Photoshop CC 2015 (Adobe systems Ltd, Europe, Uxbridge, UK) was used for measurement. Gingival height was analyzed using panoramic view radiograph. Mesial and distal gingival height and fixture length were measured to calculate the estimated sulcus depth.
In this study, only 9.23% of screw-cement retained implant restorations had no UCRs. The rate of UCRs was significantly higher in molar than in premolar (p=0.048). Distal gingival height has negative correlation with the rate of UCRs on distal area. The wider the total restoration area was, the higher the rate of UCRs was. Buccal, lingual, and mesial gingival height showed no significant correlation with the rate of UCRS on each surface area.
1. Regardless of vent hole, excess cement might be remained undetected after meticulous cleaning of cement remnant in the implant supported restorations. Sulcus depth was not significantly correlated with undetected cement excess.
2. Screw or screw-cement retained implant restorations could be recommended in the viewpoint of peri-implantitis due to residual cements.
3. Excess cement could be remained undetected after cementation and cleaning of implant restorations, especially using customized abutment. It is necessary for implant dentistry to introduce innovative method of retention of restorations.