Wadhwant et al Residual excess cement (REC) is a common complication of cement-retained prostheses and has been linked to peri- implant disease. Removal of the cement residue may result in resolution of the issue if addressed early in the disease process. However, this is dependent upon the ability to locate and adequately remove the foreign material. This series of patient scenarios describes the ability to detect REC by using dental radiography. Characteristics related to cements and flow patterns specific to implants are addressed. (J Prosthet Dent 2012;107:151-157) Radiographic detection and characteristic pat terns of residual excess cement associated with cement- retained implant restorations: A clinical report Chandur Wadhwani, BDS, MSD, a Darrin Rapoport, BDS, MSD, b Silvia La Rosa, DDS, c Timothy Hess, DDS, d and Stefanie Kretschmar, Dr med dent, MSD e University of Washington, Seattle, Wash Presented at the 2011 Pacific Coast Society of Prosthodontics Meeting, Pasadena, Calif. a Private practice, Bellevue, Washington and Affiliate Faculty, Department of Restorative Dentistry. b Private practice, Tukwila, Washington. c Private practice, Tacoma and Gig Harbor, Washington. d Private practice, Auburn, Washington. e Private practice, Stuttgart, Germany. Residual excess cement (REC) is a common complication of cement- retained implant prostheses 1,2 that can result in a local inflammatory process which has been documented as a cause of periimplant disease. 3,4 The etiology is not fully understood but is believed to relate to bacterial colonization of the foreign material, which can occur several years after the restoration has been completed. 5 If the REC is identified and removed, the majority of problems can be re- solved. 5 The prevention of cement extrusion during the restoration pro- cess beyond the restorative cement margins cannot be underestimated; however, this may be more difficult than it appears. In vitro model sys- tems have demonstrated the difficulty in controlling and removing REC 6 by visual and tactile means even when supragingival crown/ abutment mar- gins have been placed. 7 Radiographic evaluation allows for a noninvasive evaluation of the site to locate REC. Detection is influenced by factors such as the composition of the ce- ment, 8,9 the amount, and the site. Other disciplines within dentistry 10 have required radiopacity specifica- tions for cements, but no mandatory minimal standard specification exists for implant cements. 11 This clinical report highlights varying degrees of REC detection by using intraoral den- tal radiographs. The radiographic de- tection and characteristic patterns of cement flow are also described. CLINICAL REPORT Patient 1: Cement superimposition A 48-year-old man in good gen- eral health presented for replacement of the maxillary right central incisor that had been extracted 6 months earlier. Initial impressions were made, followed by diagnostic waxing and the fabrication of a surgical guide. The guide was used to direct the im- plant placement such that the head of the implant (Standard Plus Implant, Regular Neck; Straumann, Andover, Mass) was located 3 mm below the proposed facial gingival margin. A 3 mm high healing abutment (Strau- mann) was placed at the time of surgery, and an interim removable prosthesis was provided for the pa- tient during the healing phase. Four months after the implant placement, clinical and radiographic integration was confirmed, and the patient was referred for the definitive restoration. This consisted of a metal ceramic crown cemented with a zinc oxide and eugenol cement (TempBond, Kerr Corp; Orange, Calif ) onto a cast gold custom abutment (SynOcta gold abutment; Straumann). Seven months after completion of the restoration, the patient present- ed with a draining sinus tract on the midfacial aspect of the implant site (Fig. 1A). A size 20 ISO gutta percha point (Henry Schein, Melville, NY) was placed into the sinus tract (Fig. 1B), and a radiograph was made. The gutta percha point terminated at the