Magnitude and reproducibility of forces generated by clinicians during laceback placement

Abstract

Objective: To determine the magnitude and reproducibility of forces generated by clinicians during laceback placement using a force-measuring typodont.

Setting: An in vitro investigation.

Materials and methods: An in vitro typodont model was developed, which incorporated strain gauges attached to a personal computer to allow measurement of the force generated on application of lacebacks. Ten operators were instructed to place lacebacks five times, on two separate occasions (T1 and T2). Inter-operator and intra-operator forces produced at T1 and T2 were compared.

Main outcome measures: Forces generated by laceback placement.

Results: The forces generated by clinicians ranged from 0 to 11.1 N. There were significant differences in the mean forces generated by the different operators (P < 0.001), with differences between time points not being consistent across all operators (P < 0.001). Some operators were more consistent than others in the forces generated.

Conclusion: In vitro, there was a large inter-operator variation in the forces produced during laceback placement. With the in vitro model used in this study, few operators applied similar forces when placing lacebacks on two separate occasions.

Keywords:

• Lacebacks
• force magnitude
• typodont

Acknowledgments

The authors are grateful to Professor W. J. S. Kerr, for funds to purchase the necessary equipment, and to Mr J. Brown for the fabrication of the typodont. Thanks are also due to Dr M. Dixon and Dr M. Lyons for their advice concerning data acquisition and to the operators who agreed to take part in this study.