Objective

To determine the effects of static frictional resistance on varying the ligation technique in a Delta Force bracket system (Ortho Organizers Ltd, Hampton, UK) and using increasing degrees of bracket/archwire angulation to simulate binding.

Design

An ex vivo laboratory investigation using the Instron Universal Testing Machine (Instron Ltd, High Wycombe, UK) to generate sliding forces on an archwire through the Delta Force bracket. The system was lubricated with Saliva Orthana artificial saliva (Nycomed Ltd, Buckinghamshire, UK).

Setting

Biomaterials Laboratory, Eastman Dental Institute, London, UK.

Materials and method

Ninety Delta Force brackets were tested against 0.018-inch stainless steel wire. Three modes of ligation were tested with three different angulations: 0, 5 and 10° to simulate increasing levels of binding.

Results

The average static frictional resistance went from 0.20 N, at 0° angulation and minimum ligation, to 2.37 N with 10° angulation and maximum ligation. Results revealed that the ligation pattern was found to be highly statistically significant (P<0.001) in influencing frictional force. The binding angle showed a trend of increasing frictional force with increasing bracket/archwire angulation. Repeatability testing showed no evidence of bias (P=0.171).

Conclusions

These results suggest that the Delta Force variable ligation system does in fact enable friction to be varied, which may have implications in clinical application.

Search results

An Ex Vivo Laboratory Study to Determine the Static Frictional Resistance of a Variable Ligation Orthodontic Bracket System