Performance and Strength Characteristics of Suture Knots in Periodontal Microsurgery: An In Vitro Study.

Background: This study is aimed to investigate the types of knot failure (untying or breaking) and the tension required to break different sutures diameters.

Methods: One hundred and fifty knots were fabricated using polyamide sutures diameters of 6/0, 7/0, and 8/0. The studied knots were either squared or slipped with different numbers of throws (2, 3, 4, 5 and 6), and the following data were recorded: type of failure (untied or broken), number of throws, the tension required to untie or break each knot, slippage, and elongation of the knot. The knots were created in a standardized way. with a device and weights and then subjected to a controlled tension.

Results: The knots that got untied were: 1=1, 1x1, 2=1, and 2x1, whereas the remaining knots got broken. Notably, at least three throws were required to prevent untying, but separately, as in 1=1=1 or 1x1x1. The mean tension to break the knots of 6/0, 7/0, and 8/0 sutures were 3.1, 1.3, and 0.6 N, respectively (P < 0.05), and they were independent of the knot type.

Conclusion: Results from this study demonstrated that the knots with geometries of 2=2/2x2 and 1=1=1/1x1x1 were secure, and additional throws does not increase their security. Furthermore, tensile strength reduces with decreased suture size.