The effect of tensile strength on the clinical effectiveness and patient acceptance of dental floss

Comparison of dental flosses - an investigation of subjective preference and mechanical properties

Objective

To investigate the properties (tensile strength, roughness, abrasiveness) of different dental flosses and how these properties relate to subjective preference for floss by users.

Materials and method

Four flosses of differing compositions were selected (polytetrafluoroethylene (PTFE), nylon, silk, and ultra-high-molecular-weight polyethylene (UHMWPE)). Tensile strength (TS) was measured utilising a universal testing machine (total n = 40). Surface roughness (Ra) was measured on 3D reconstructed models of scanning electron microscope and abrasiveness was measured through block-on-ring tests against human enamel. Subjective preference for floss was measured by asking a sample of 16 individuals to use each floss for an 8-day period using a split-mouth design.

Results

The highest TS was found in UHMWPE floss (194.18± 24.61 MPa) while the lowest TS was found in PTFE floss (11.78± 0.77 MPa). Silk floss had the highest Ra (0.304± 0.025 µm) while PTFE floss had the lowest (0.048± 0.003 µm). In-vitro abrasion testing of the flosses identified no significant differences between the flosses in causing wear on tooth enamel. Subjective ratings of flosses indicated PTFE floss to be most preferred and nylon floss to be least preferred.

Conclusion

There was a difference in subjective preference between dental flosses composed of different materials. The PTFE floss was the overall most preferred while the nylon floss was the least preferred. There was also an association between the mechanical properties and preference for their usage, with PTFE floss being the most preferred but having the lowest surface roughness and tensile strength.

Clinical Relevance

This study compared a wide range of mechanical properties and subject preferences of commercially available dental floss. The results of this study can provide guidance for the recommendation of dental floss for oral hygiene routines.

Gliding capacity of different dental flosses

BACKGROUND

One of the major concerns with the use of dental floss is the passage of the proximal contact, which might be influenced by the material characteristics of the floss. The aim of this study was to compare the gliding capacities of different flosses with major differences in structure and experimental behavior in vivo.

METHODS

In a clinical, single-blind, crossover study of 27 subjects, the forces necessary for passing all 14 proximal contacts between the first premolars were measured using 2 polytetrafluoroethylene (PTFE)-based flosses, 2 nylon-based flosses, and 1 nylon-based tape. The flosses were fixed in a special holder with strain gauges, which allowed registration of the maximum forces at insertion into and removal from the interdental area.

RESULTS

In most contacts, the PTFE flosses needed less force compared to the nylon flosses. The range between the flosses was higher in the mandible compared to the maxilla and increased from the mesially located contacts to the more distally located contacts. The nylon tape required higher forces at insertion for all maxillary contacts. All other flosses proved to be equivalent at these contacts.

CONCLUSIONS

PTFE flosses are superior to nylon flosses in terms of passing stronger proximal contacts in both directions. Due to gliding differences between different types of floss, the selection of a floss has the potential of compensating intra- and interindividual variation in contact strengths.