A new CAD/CAM tooth mobility simulating model for dental in vitro investigations

Abstract

Objectives To validate a new tooth mobility simulating in vitro model for biomechanical tests of dental appliances and restorations. Material and methods Load-deflection curves for teeth in CAD/CAM models (n = 10/group, 6 teeth/model) of the anterior segment of a lower jaw with either low tooth mobility (LM) or high tooth mobility (HM) were recorded with a universal testing device and a Periotest device. All teeth were tested before and after different ageing protocols. Finally, vertical load capacity (Fmax) was tested in all teeth. Results At F = 100 N load, vertical/horizontal tooth deflections before ageing were 80 ± 10 µm/400 ± 40 µm for LM models and 130 ± 20 µm/610 ± 100 µm for HM models. Periotest values were 1.6 ± 1.4 for LM models and 5.5 ± 1.5 for HM models. These values were within the range of physiological tooth mobility. No visible damage occurred during ageing and simulated ageing had no significant effect on tooth mobility. Fmax values were 494 ± 67 N (LM) and 388 ± 95 N (HM). Conclusion The model is practical, easy to manufacture and can reliably simulate tooth mobility. The model was also validated for long-term testing, so is suitable for investigating various dental appliances and restorations such as retainers, brackets, dental bridges or trauma splints. Clinical relevance Using this in-vitro model for high standardised investigations of various dental appliances and restorations can protect patients from unnecessary burdens in trials and practice.

Finite Element Analysis of Fixed Orthodontic Retainers

“…By varying the material properties of the periodontal ligament, it was possible to achieve low (1 µm/N), medium (2 µm/N), or high (3 µm/N) TR values in the vertical direction. Previous studies [18,19] have indicated that the ratio between the horizontal and vertical TR should lie between three and four. Detailed information about the simulated TR is presented in Table 2.…”