A 5-Year Retrospective Assay of Implant Treatments in Private Practice: The Restorative Complications of Long-Span Implant-Supported Fixed and Removable Dental Prostheses

Purpose: To describe and analyze the restorative complications of long-span (> three units) implant-supported dental prostheses (LIDPs) in 27 private practices in the state of Victoria, Australia, during the period from January 1, 2005, to December 31, 2009. Materials and Methods: Private dental practitioners providing implant treatment were invited to enroll in this study, which was conducted through a dental practice-based research network. Clinical records of the implant treatments, which were provided during the specified period, were accessed for data collection. LIDPs included implant-supported prostheses of fixed or removable design; namely, fixed partial dentures (IFPDs), fixed complete dentures (IFCDs), removable partial dentures (IRPDs), and complete overdentures (IODs). Descriptive statistics and generalized linear mixed modeling were used for data analysis. Results: The range of observation time for 627 LIDPs was 3 to 72 months (mean +/- SD: 3.22 +/- 1.49 years). For fixed prostheses, the complication with the highest annual rate was veneer fracture (acrylic: 21%; ceramic: 2.9%), followed by loss of retention for cement-retained IFPDs (14.7%). For mandibular IODs, the highest annual complication rate was for retention complications, whereas for maxillary IODs, it was for acrylic veneer fracture (11.5% and 6.4%, respectively). The peak incidence of complications was during the first year of function in fixed protheses and in IODs. Acrylic veneer fracture in IFCDs and IOD base fracture were more common in patients with preoperative clinician-reported attrition (estimated odds ratios [ORs] = 4.5 and 11.3, respectively; P < .05). Ceramic veneer fracture in fixed protheses and acrylic veneer fracture in IODs were reported more commonly for maxillary compared to mandibular prostheses (ORs = 5 and 22, respectively; P < .05). Mandibular IODs had more frequent retention complications when supported by two compared to four implants (OR = 5.9, P < .05). Conclusion: Restorative complications were observed in all categories of LIDPs at various annual rates. Clusters of these complications occurred during the first year of prosthesis function. Patient- and prosthesis-related variables influenced the incidence rate of some of these complications.