22 December 2023

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Effective ligatures for correct isolation with the rubber dam

Simona Chirico

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The SARS-CoV-2 (Covid-19) pandemic has made the rubber dam (RD) an indispensable tool for the majority of dental procedures, as as a preventive measure it is able to protect operators from the risk of contagion at due to exposure to saliva, blood and aerosols/droplets produced during dental procedures.

Literature studies have shown that once the dam has been positioned adequately, there is a reduction in bacterial aerosols of around 70-98.9%, significantly limiting the inhalation of infectious aerosols by dental personnel.

RD also protects the patient from the possible aspiration or ingestion of instruments, medications, irrigating solutions and tooth debris/materials, protecting dentists from possible future legal liabilities, as well as allowing the isolation of the operating field from saliva and organic liquids which, in contact with the dental elements undergoing treatment, can compromise the success of adhesive and disinfection techniques in endodontics.

Based on the above-mentioned advantages, RD isolation is now considered standard practice by dental professionals. However, for optimal isolation and to keep the dam in the correct position it is also possible to use wooden wedges or ligatures with dental floss, suitable for isolation procedures of the entire quadrant or multiple teeth.

Materials and methods

In a study published in the Journal of Prosthodontic, the authors introduced the classification of dental floss ligatures used during rubber dam placement, useful for optimizing this procedure in dentistry. Ligatures are divided into traditional, self-ligating single-loop and self-ligating double-loop, as well as those with a new state-of-the-art “compound ligature” design that incorporates a combination of one or more simple ligatures.

This new design can provide better isolation and more consistent gum tissue retraction. Furthermore, thanks to the advanced technique applied, the composite binding offers better stability and prevention of the dam sheet from slipping over the binding by almost hermetically isolating every small surface.

The authors propose this new classification of ligatures performed with dental floss for excellent isolation using a rubber dam:

• simple ligatures;
• compound ligatures.

SIMPLE LIGATURES

• Traditional ligation (surgical knot): where a knot is created, with the surgical suture interrupted, by positioning the dental floss around the neck of the tooth at the height of the gum contour. A suitable length (20-30cm) is cut and doubled into a U shape, placed around the neck of the tooth where a double knot is then created in a clockwise direction. The knot is then tightened securely around the tooth by subsequently tying a single knot in an anti-clockwise direction. The main advantage of this method is the fact that it is quick and easy to implement; however, the risk of this type of ligature is that it may loosen after application.
• Single-loop self-ligating ligature: This knot is prepared outside the patient's mouth. A piece of dental floss of suitable length (20-30 cm) is cut and folded in two into a U shape. A loop is then created by passing the curved end of the dental floss over the two free ends. The knot is then placed around the cervical area of the tooth and then tightened towards the neck of the tooth.
• Double-loop self-ligating ligature: This ligature is similar to the single-loop self-ligating one but with two turns. A piece of dental floss of suitable length (20-30 cm) is doubled into a U shape and a loop is created by passing the two free ends over the curved end of the dental floss. However, unlike the single-loop self-ligating ligature, the curved end is inserted inside the loop and only partially pulled out. The curved end of the floss is then opened, brought around the entire knot until it encircles the free ends. Finally, the free ends are pulled to tighten the double loop down. Generally the double-twist self-ligating ligature is easier to tighten as it allows the dentist to separate the loose ends or together to tighten the knot, allowing him to tighten with one hand if necessary. The double-wrap ligature is also tighter and more stable around the neck of the tooth.

COMPOUND LIGATURES

This ligature, proposed and implemented by the author of this article, Dr. Osama A. Alkhatib, consists of a single or double loop self-ligating ligature attached to one, two or more knots. This ligature is designed to isolate teeth prepared for crowns, bridges, or cavities with deep margins, especially palatal and lingual cavities.

Conclusions

The compound ligation design can provide better isolation and more consistent gum tissue retraction than other types of ligations. Furthermore, thanks to the advanced technique applied, this ligature will offer better stability, preventing the dam sheet from sliding over the ligature itself.