Advanced biomaterials used for a new telescopic retainer for removable dentures.

Telescopic retainers with conical ceramic abutment crowns and electroplated gold copings define a new retainer for removable dentures exhibiting favorable tribological properties that could offer clinical advantages. The objective of this study was to evaluate the clinical effects of this retainer. To do so, a novel treatment modality was developed based on intraoral bonding of the copings to the framework in order to be able to realize, in a clinical setting, the retainer function based on a precision fit. A total of 32 patients wearing 33 dentures (16 mandibular, 17 maxillary; period of risk [months]: minimum = 3; maximum = 58; mean = 27.6), supported by 147 abutments (83 natural teeth, 64 implants) with ceramic abutment crowns (IPS Empress 1, IPS Empress 2, InCeram, Procera, CerAdapt; CeraBase) were followed at 6-month intervals. The ceramic abutment crowns showed low plaque accumulation (mean PI = 17.3%). The gingival tissues around natural abutments were generally free of inflammation; so was the mucosa around the implants (mean SBI = 4.9%). Denture adhesion and occlusion did not change, and there were no rocking movements. The mobility (as determined by Periotest) of 29 teeth was reduced in a highly significant manner within 6 months (t test, p < 0.001). Osseointegration was preserved for all implants. One abutment loosened. Six Empress 1 ceramic copings failed (94.6% Kaplan-Meier survival rate), and one abutment tooth was lost (99.2% survival rate). All patients reported problem-free handling, no rocking movements, and constant adhesion. The adhesive strength of one denture was too low at insertion. 94% of the patients experienced no problems with oral hygiene. The retainer examined has relevant clinical advantages and meets geriatric requirements for removable dentures. Copyright 2000 John Wiley & Sons, Inc.