An in vitro evaluation of resonant frequency analysis to measure fixed bridge stability

To determine whether a clinically available resonance frequency analysis (RFA) device (Osstell Mentor), designed to assess implant integration, could identify a single uncemented retainer on fixed-fixed bridges, in vitro.

All-metal fixed-fixed bridges were cemented to acrylic tooth analogue abutments with simulated periodontal ligaments. Dental stone bases provided 100 or 50% 'bone support' groups (n = 50 in each). Control groups had both retainers cemented, whereas the test groups had the 'premolar' uncemented, mimicking clinical failure. A RFA device was used to measure bridge stability, expressed as a modified Implant Stability Quotient (Bridge Stability Quotient-BSQ) from a Smartpeg temporarily affixed to the bridge via composite.

The BSQ recorded at the premolar site in both 100 and 50% support models demonstrated highly statistically significant differences (P <0.003) between the control and test groups. Sensitivity and specificity, area under the curve (receiver operating characteristic), analyses showed moderate test accuracy (0.735) for the 100% support group and good accuracy (0.96) for the 50% support group.

The investigation suggests that RFA measurements were able to identify, reliably and non-destructively, in vitro, fixed-fixed bridges where the anterior retainer was uncemented. Further clinical research is required to determine whether this technique may allow early diagnosis of failing bridgework.