Dental floss ties for rubber dam isolation: A proposed classification and a new technique

Abstract

Rubber dam application has become an essential part of restorative dentistry. In late 2019, dentistry faced a new challenge with the COVID‐19 pandemic and therefore, the implementation of extra isolation methods became crucial. This article introduces a classification of dental floss ties used with a rubber dam, including the “simple” ties that are subdivided into traditional ties, single‐loop self‐ligating ties and double‐loop self‐ligating ties, and a new state‐of‐the‐art design. The “compound tie” design incorporates a combination of one or more subdivisions of the simple ties. This new design may provide better isolation and more consistent gingival tissue retraction. Furthermore, due to the advanced technique applied, the tie will offer improved stability and prevent the sheet from sliding over the dental floss tie from all surfaces.

The SARS‐COV‐2 (COVID‐19) pandemic created a significant challenge for healthcare providers, and their delivery of care. Dental professionals appear to be at high risk of contagion due to exposure to saliva, blood, and aerosol/droplet production throughout the majority of dental procedures. ¹ , ² , ³ In an attempt to limit contagion, the use of a rubber dam (RD) was recommended as a preventative measure. ⁴ , ⁵ When RD was used, a reduction in bacterial aerosols was reported to be around 70‐98.9%, significantly minimizing the inhalation of infective aerosols by dental personnel. ⁶ , ⁷ It was suggested that during many dental procedures, using RD could eliminate almost all means of contamination arising from saliva and blood. ⁸

On the other hand, based on the increase in requests for esthetic restorations over the last few decades, adhesive dentistry has become a routine procedure in any dental practice. One critical factor that affects the success of direct or indirect resin‐bonded restorations is moisture control. Gingival fluid, blood, or saliva contamination can affect the strength of resin bonding to the tooth structure which can lead to loss of restorations, recurrent caries, postoperative sensitivities, and discoloration. ⁹ The use of RD is currently considered a gold standard procedure. ¹⁰

Isolation with RD is increasingly being used in endodontic, pediatric, and restorative dentistry during standard treatment procedures due to several advantages. A significant increase in shear bond strengths and microleakage reduction of composite resin restorations were obtained following clinical procedures when RD isolation was used, in comparison with cotton roll isolation. ¹¹ , ¹² Whenever resin cement is used for the cementation of all‐ceramic restorations, RD placement is recommended to ensure a dry field. Additionally, adequate retraction around the gingival margins permits good visual access for excess cement removal. ¹³

The use of RD has other reported benefits. RD placement protects the patient from possible aspiration or swallowing of instruments, medicaments, irrigating solutions, and tooth/material debris which in turn will protect dentists from possible future legal responsibilities. ¹⁴ , ¹⁵ , ¹⁶ Based on the above‐mentioned advantages, RD isolation is now considered standard practice by dental professional organizations. ¹⁷ , ¹⁸ With the spread of the COVID‐19 virus, strict and effective infection control protocols are crucial. The use of RD with high‐volume aspirator tips can help minimize aerosol or spatter in dental procedures. It prevents the virus from spreading further and helps control any pandemic situation. ¹⁹

Different designs of clamps/retainers are available for use on individual teeth or a group of teeth to secure the RD sheet in place. However, wooden wedges, wedging/stabilizing cords, or dental floss can also be used to keep it in place. ²⁰ For limited operative procedures, it is usually acceptable to isolate fewer teeth, while isolating a greater number of teeth is indicated for quadrant procedures.

Techniques for applying RD have been described in the literature, each with its own merits. ²⁰ , ²¹ , ²² Whatever isolating technique is used, ligation with floss and knotting the floss around the tooth/teeth is recommended to stabilize the RD in position. ²³

A surgeon's knot has been described to secure the dental floss ligature/tie. ²¹ , ²⁴ However, there has been no study in the literature classifying floss ties for dental uses. The author (O.A.) proposes a classification of dental floss ties for isolation purposes and presents a new technique for tying dental floss.

CLASSIFICATION OF DENTAL FLOSS TIES

Generally, a dental floss tie consists of one or two loops, a knot, and two free arms. The term overhand knot has been used for surgical purposes to provide a secure stopper when intending the suture to be permanent. The author (O.A) proposes a new classification of dental floss ties as described below:

• 1.
  Simple ties: subdivided into:

  • I.
    Traditional tie (surgeon's tie): A knot is created after placing the dental floss around the neck of the tooth gingival to the height of the contour. This tie is similar to an interrupted surgical suture in shape. A suitable length (20‐30 cm) is cut and doubled up into a U shape, then placed around the neck of the tooth and a double overhand knot is created clockwise. The knot is then tightened securely around the tooth followed by making a single overhand knot counterclockwise. ²⁴ , ²⁵ The main advantage of this tie is the quick and easy application; however, it may become loose soon after application. Figure 1 demonstrates the step‐by‐step procedure of making this traditional tie and its clinical application.
  • II.
    Single‐loop self‐ligating tie: This knot is prepared outside the patient's mouth. A piece of dental floss of suitable length (20‐30 cm) is cut and doubled up into a U shape. A loop is then created by passing the curved end of the dental floss over the two free ends as shown in Figure 2. The curved end of the dental floss is then inserted inside the loop and pulled out completely to create a loose tie. The loop is placed around the cervical area of the tooth and then tightened toward the neck of the tooth by pulling its free ends apart until it is tight and secure. ²⁵
  • III.
    Double‐loop self‐ligating tie: This tie is similar to the single‐loop self‐ligating tie but with two loops. A piece of dental floss of suitable length (20‐30 cm) is doubled up into a U shape, and a loop is created by passing the curved end of the dental floss over the two free ends. However, unlike the single‐loop self‐ligating tie, the curved end is inserted inside the loop and only partially pulled out. The curved end of the dental floss is then opened up, brought over around the entire knot until it encircles the free ends. Finally, the free ends are pulled to tighten the double loops downward. Figure 3 illustrates the step‐by‐step procedure for preparing this tie. Generally, the double‐loop self‐ligating tie is easier to tighten as it enables the dentist to pull the free ends either apart or together to tighten the knot, allowing them to tighten it with one hand if needed. ²⁵ Conversely, the single‐loop self‐ligating tie only allows the dentist to tighten the knot by pulling the two ends apart using both hands. The double‐loop tie is also tighter and more stable around the neck of the tooth. ²⁵

  FIGURE 1.

  

  Traditional tie. (a‐c): Step‐by‐step illustration of the dental floss tie. (a): A piece of dental floss made into a U shape. (b): A double overhand knot clockwise created. (c): A single overhand knot anticlockwise created. (d‐i): Clinical application. (d): A piece of dental floss of suitable length (20‐30 cm) placed around the neck of the tooth. (e): A double overhand knot created clockwise. (f): Knot tightened. (g): A single overhand knot created anticlockwise. (h): A flat metal instrument used to ensure the floss tie is secured palatally beyond tooth bulbosity cervically. (i): The knot tightened toward the neck of the tooth by pulling its free ends apart until it is tight and secure.

  FIGURE 2.

  

  Single‐loop self‐ligating tie. (a‐d): Step‐by‐step illustration of the dental floss tie. (a): A piece of dental floss of suitable length (20‐30 cm) doubled up into a U shape. (b): A loop is created by passing the curved end of the dental floss over the two free ends. (c): The curved end of the dental floss is inserted inside the loop and pulled out completely. (d): The open‐ended loop is placed around the neck of the tooth, then tightened. (e‐h): Clinical application. (e): The loop prepared outside the patient's mouth. (f): The loop placed around the cervical area of the tooth. (g): A flat metal instrument used to ensure the floss tie is secured palatally beyond tooth bulbosity cervically. (h): The knot tightened toward the neck of the tooth by pulling its free ends apart until it is tight and secure.

  FIGURE 3.

  

  Double‐loop self‐ligating tie. (a‐f): Step‐by‐step illustration of the dental floss tie. (a): A piece of dental floss (20‐30 cm) doubled up into a U shape. (b): A loop created by passing the curved end of the dental floss over the two free ends. (c): The curved end inserted inside the loop and partially pulled out. (d): The curved end of the dental floss opened up and brought around the entire knot. (e): The action continued until it encircles the free two ends. (f): The free ends held and pulled to tighten the double loops downward. (g‐j): Clinical application. (g): The double‐looped tie prepared outside the patient's mouth. (h): The loop placed around the cervical area of the tooth. (i): A flat plastic instrument used to ensure the floss tie is secured palatally beyond tooth bulbosity cervically. (j): The knot tightened toward the neck of the tooth by pulling its free ends either apart or together to tighten the knot.

• 2.Compound tie: This tie, which was proposed and implemented by Dr. Osama A. Alkhatib, consists of a single‐loop or double‐loop self‐ligating tie attached to one, two, or multiple overhand knots followed by another overhand knot. This tie is designed to isolate prepared teeth for crowns, bridges, or cavities with deep margins, especially palatal and lingual cavities. It provides complete access to prepared teeth and appropriate isolation by the RD. Figure 4 shows the step‐by‐step procedure of making a compound tie (1) that consists of a single‐loop self‐ligating tie attached to an overhand knot, followed by another overhand knot, while Figure 5 demonstrates a compound tie (2) consisting of a double‐loop self‐ligating tie attached to overhand knot, followed by another overhand knot.

  FIGURE 4.

  

  Compound tie 1 (consists of single‐loop self‐ligating tie attached to overhand knots). (a‐g): Step‐by‐step illustration of the dental floss tie. (a): A single‐loop self‐ligating tie created. (b): The dental floss inserted in the loop and folded into a U shape. (c): The overhand knot made around the loop. (d): The overhand knot tightened around the loop. (e): Another overhand knot made behind the first one for more retention. (f): The overhand knot tightened. (g): Second overhand knot attached to the loop of self‐ligating tie next to the first one if needed. (h‐k): Clinical application. (h): Single‐loop self‐ligating tie attached to the overhand knots prepared outside the patient's mouth. (i): The loop placed around the cervical area of the tooth. (j): A flat metal instrument used to ensure the floss tie is secured palatally beyond tooth bulbosity cervically. (k): The knot tightened toward the neck of the tooth by pulling its free ends apart and then secured around the clamp on adjacent teeth.

  FIGURE 5.

  

  Compound tie 2 (consists of double‐loop self‐ligating tie attached to overhand knots). (a‐g): Step‐by‐step illustration of the dental floss tie. (a): A single‐loop self‐ligating tie created. (b): The dental floss inserted in the loop and folded in a U shape. (c): The overhand knot made around the loop. (d): The overhand knot tightened around the loop. (e): Another overhand knot made behind the first one for more retention. (f): The overhand knot tightened. (g): Second overhand knot attached to the loop of self‐ligating tie next to the first one if needed. (h‐k): Clinical application. (h): Double‐loop self‐ligating tie attached to overhand knots prepared outside the patient's mouth. (i): The loop placed around the cervical area of the tooth. (j): A flat metal instrument used to ensure the floss tie is secured palatally beyond tooth bulbosity cervically. (k): The knot tightened toward the neck of the tooth by pulling its free ends apart and then secured around the clamp.

DISCUSSION

In some cases, it might not be feasible to use clamps, necessitating the use of floss ligatures to secure the dam (Figures 6a‐f). There are numerous advantages of using dental floss tie techniques compared to clamps. A dental floss tie provides complete access to the prepared tooth, while clamps may impede good access ²¹ (Figure 6a,b). In addition, it can be safely used to isolate teeth with orthodontic brackets, as clamps may damage the brackets or debond them during insertion and removal (Figure 6c,d). Also, with the use of the dental floss tie techniques, indirect restorations can be tried‐in easily which may be more difficult when dental clamps are in place. Moreover, if the clamp does not fit the tooth correctly, or is not seated fully, it can dislodge and be aspirated or swallowed. ²⁶

FIGURE 6.

(a,b): Isolation of multiple teeth after removing old crowns with clamps versus dental floss ties. (a): Isolation with clamps impedes direct access to teeth. (b): Compound ties provide complete access to prepared teeth. (c,d): Dental floss ties can be safely used to isolate teeth with orthodontic brackets. (c): Teeth with orthodontic brackets before isolation. (d): Teeth after isolation using compound ties instead of clamps. (e,f): Isolation of multiple teeth using compound ties instead of anchor clamps. (e): Teeth after removing old crowns. (f): Teeth after isolation using compound tie instead of anchor clamps for the premolars, in addition to the central incisors, and double‐loop self‐ligating tie for lateral incisors. (a‐f): Clinical applications of the dental floss ties.

In some clinical scenarios, dental floss ties are more suitable around teeth as opposed to clamps, whereby the latter may require additional fixation using impression compound or flowable composite. ²³ Dental floss ties are less traumatic to the gingival tissue than clamps, particularly active clamps, which can cause trauma to the gingival tissue and eventually irreversible gingival recession. The author suggests that the compound tie can be easily used if a dentist wants to isolate teeth from the second to the second premolar without the need for using anchor clamps and local anesthesia, as premolar teeth may have sufficient undercut to retain the floss ligature (Figure 6e,f). When molar teeth need to be isolated, the floss tie is not recommended as the pressure caused by the RD sheet may force the sheet to slide over the buccal knot. This is due to the fact that molars are located posteriorly with unfavorable undercuts leading to extra tension on the RD sheet compared to anterior teeth and premolars.

Different knot types have been investigated in the literature for surgical application in terms of loop and knot security, ²⁵ , ²⁷ , ²⁸ but no study yet has classified different floss ligatures/ties for dental use. The compound tie technique may have an advantage over single‐ or double‐loop self‐ligating tie techniques as it can provide better isolation and more consistent gingival tissue retraction from the palatal and labial tooth surfaces simultaneously. The knots described in the compound tie prevent the RD sheet from sliding over the dental floss tie from all surfaces, as there are at least two knots: one on the palatal surface and one on the labial surface. When there is only one knot on the labial surface of the tooth using the traditional technique, for example, the RD sheet may slide over the dental floss tie from the palatal or lingual surface if stretched too far. Moreover, a compound dental floss tie has labial arms and lingual or palatal arms. This will enable the dentist to pull both arms simultaneously, which in turn will pull the entire loop in the same direction of pulling, achieving good gingival retraction from all the surfaces of the tooth (Figure 7). On the other hand, simple ties have only labial arms, therefore, when the dentist pulls the labial arms, it may achieve good retraction from the labial surface only. In some cases, the loop might slide in the opposite direction of the pulling, especially with teeth prepared for indirect crowns, or remaining roots that require building up with posts, which may not have enough retention areas around the neck of the tooth to retain the loop in place.

FIGURE 7.

(a‐c): (a): Compound dental floss tie; when pulling the arms of the compound dental floss tie simultaneously, the loop will move (slide) in the same direction of the pulling, achieving good gingival retraction from all the surfaces. (b): Simple dental floss tie; when pulling the arms of the simple dental floss tie, the loop may slide down in the opposite direction. (c): In the case of using two dental floss ties, the second one will face the thickness of the knot of the first tie inside the gingival groove, and the loops of the two dental floss ties will be in different levels which internally makes them thicker than the compound tie.

To achieve adequate RD isolation, two opposing dental floss knots may be required. This will help stabilize the RD sheet around the neck of the tooth from all surfaces and provide good gingival retraction (e.g., to expose the margins of a prepared crown). In such clinical scenarios, a dentist may opt to use two simple dental floss ties, the first one having a knot on the labial surface of the tooth and the second one with a knot on the palatal surface of the tooth. However, using a compound dental floss tie has an advantage over using two simple dental floss ties. When using a compound dental floss tie, every knot will be at the same level of the loop, allowing the minimal thickness of the dental floss tie, which may enable retraction of the gingival tissues and exposure of the margins, with minimal pressure on the gingiva.

SUMMARY

A new classification and technique of dental floss ties are proposed in order to simplify isolation when using an RD, provide a good seal, enhance visibility, and offer good access to prepared teeth, especially for indirect restorations. With this simple system, the stress of getting limited access or clamp dislodgement may be considerably reduced. Future research could further evaluate the clinical effectiveness of isolation with the proposed floss ties.

CONFLICTS OF INTEREST

The authors do not have any conflicts of interest in regard to the current study.

Alkhatib OA, Bissasu S, Daud A. Dental floss ties for rubber dam isolation: A proposed classification and a new technique. J Prosthodont. 2023;32:83–89. 10.1111/jopr.13611