Cement-Associated Signs of Inflammation: Retrospective Analysis of the Effect of Excess Cement on Peri-implant Tissue

Purpose: Excess cement left in the peri-implant sulcus after the placement of prosthetic restorations risks inflammation in the peri-implant tissue. While many current studies deal with the question of how to avoid undetected excess cement, relatively little is known about the clinical consequences of this complication. This study analyzed the clinical findings associated with excess cement. Further, the influence of the sojourn time of undetected excess cement in the peri-implant pocket on clinical findings was investigated. Materials and Methods: Within the scope of a retrospective clinical follow-up, the suprastructures that were originally cemented with a methacrylate cement were revised in 93 patients (171 implants). The patients were split into two groups according to the time between placement of the prosthetic restoration and revision. Group 1 (G1) had treatment revisions within 2 years of restoration placement (71 patients with 126 implants); in group 2 (G2), treatment revisions were conducted at a later time (22 patients with 45 implants). For the purpose of statistical analysis, both groups were further analyzed based on the presence/absence of excess cement at the time of revision. Results: By definition, the average time to revision in G1 was shorter than in G2 (0.71 years versus 4.07 years). There was no significant difference in the frequency of excess cement at revision between G1 (59.5%) and G2 (62.2%). The clinical findings around the implants in G1 were significantly less severe than in G2 (bleeding on probing: G1 without excess cement-17.6%, G1 with excess cement-80%, G2 without excess cement-94.1%, G2 with excess cement-100%; suppuration: G1 without excess-0%, G1 with excess cement-21.3%, G2 without excess cement-23.3%, G2 with excess cement-89.3%). After removing the excess cement, cleaning and disinfecting the implant abutment and restoration, and using a different cement, significantly fewer signs of inflammation were found at further follow-up in both groups. Conclusions: Within the limitations of this retrospective observational study, excess cement was present in a high number of cement-retained implant restorations. Signs of inflammation were present in a large proportion of implants at short- to medium-term follow-up. At the time of restoration revisions, the clinical observation of previously undetected excess cement was associated with increased prevalence of inflammation. Removal of excess cement significantly reduced the signs of inflammation.