Suturing in Medicine and Dentistry

by Peter C. Fritz, BSc, DDS, FRCD(C), PhD (Perio), Certified Specialist in Periodontics

There is a fuzzy line between surgery in the mouth and the rest of the body. Many principles are the same, however, there are certain elements of suturing that we can take from medicine and apply to dentistry providing a better outcome for our patients. In analyzing how general surgery residents are trained in the art of suturing, it is apparent that there are certain concepts that would be beneficial for dental surgeons to remember and learn from. In spending time in operating rooms in Canada, in the United States and many countries in Western Europe, a myriad of observations and approaches were collected and distilled into the following:

1. Medicine and dentistry is all about punctures. Most medical procedures require some element of “puncture”. Whether this is taking blood or operating on any tissue, a puncture of the skin or mucosa is generally involved. The pressure and the dexterity to competently perform these procedures require a great amount of skill and finesse. In dentistry, we puncture every day when we administer local anaesthetic, break through enamel into dentin, or probe past the sulcus of the inflamed periodontal pocket. One common puncturing procedure in medicine and dentistry is suturing. Both intra-orally and extra-orally, wounds need to be approximated and stabilized. Although staples, clips and adhesive systems are used during various medical procedures, suturing is common to both medicine and dentistry. The puncturing of the edges of the wound and the stabilization achieved through the punctures is critical in achieving the most favourable outcome.

2. The suturing is often left to the least experienced. In operating rooms around the world, I have observed many surgeons successfully complete very complicated and delicate procedures. The surgeon then removes his or her gloves and gives a few suggestions to his or her collaborators/assistants as they begin to close the access route. Having sutured the deeper planes, the lead surgeon often leaves the skin suturing to the least experienced surgeon who is still learning the craft. Doing this leaves one of the most fundamental phases of the surgery to the least experienced hands. Suturing the access route is a task that is generally neglected, put in place quickly and often completed “just” adequately. In oral and facial surgery, this is of fundamental importance, as a lack of primary closure can easily result in infection and scarring. In facial surgery, the consequences of a badly executed wound closure can readily be understood. Here is a question we don’t know the answer to or are afraid to ask: How many bone grafts have become infected because the suture did not provide a proper seal? How many exposed membranes or gingival recessions are linked to a technical defect in suturing? Deep healing of a wound can never be better than the quality of its surface closure. In periodontal and implant surgery, typically, approximately 70 percent of the operating time is spent suturing the wound closed.

3. Wounds are classified differently in medicine: Clean wounds are termed non-infected surgical wounds. These are without inflammation and not within the digestive, respiratory or genital system. Clean-contaminated wounds are the type we are most used to creating during oral surgery, just like the ones in the digestive, respiratory, genital or urinary system. Contaminated wounds are traumatic wound lacerations or contusions. Infected wounds are the same as contaminated wounds – a transition that occurs a few hours later.

4. A rule of thumb in medicine is that the deeper you are in the body, the larger diameter sutures you use. For example, when suturing the aorta a 3-0 suture is used. Moving further to extremities to the femoral arteries a 5-0 suture would be used and a 6-0 for the carotid arteries. In ophthalmology 10-0 or 11-0 sutures are used.

The same analogy can be made when suturing the oral tissues. The further back in the mouth, the larger diameter sutures are used. When suturing after wisdom tooth removal a 3-0 or 4-0 is used. When securing a free gingival graft a 6-0 is used, and when performing delicate surgery around anterior implants, a 7-0 is often preferred (Fig. 1).

FIGURE 1. Well stablized wound with clean monofilamet suture lines.

FIGURE 2. Using the Early Wound Healing Index (EWHI), Figure 2 shows an incomplete flap closure, flip dehisces and negative architecture. There is also necrosis of the inter- proximal tissues and the flap closure is a failure (EWHI 5).

FIGURE 3. In Figure 3, there is complete flap closure and only a fine fibrin line in the interproximal. This would have an EWHI of 2 and is a much better outcome. Two-week post-operative visit for a connective tissue graft. Note the absence of inflammation around the monofilament 6-0 sutures.

In Figure 3, the patient presents with a vertical root fracture of five years duration. The tissues are inflamed and there is a fenestration of bone and a draining sinus. The tissue is infected and the buccal plate of bone has been destroyed. The tooth was subsequently removed and the area thoroughly derided and allowed to heal for 8 weeks. After eight weeks, the ungrafted site was re-entered and an implant placed with a guided tissue regeneration procedure. It was sutured with 5-0 non-absorbable monofilament sutures and allowed to heal two weeks. After two weeks the image in Figure 5 was taken. Note the absence of inflammation around sutures and the effective wound stabilization. Six weeks following the post-operative visit, the implant was exposed and the implant-supported crown delivered four weeks post-exposure (Fig. 6).




5. Speed Kills. The rate at which a suture is pulled thr
ough the tissue has an effect on the healing of the puncture wound. A very rapid pull with a braided suture is capable of severely injuring the tissue due to “rope burn”. This is less likely with a monofilament suture as the friction is reduced through improved glide. It can be prevented by being cognizant of the rate at which you pull the suture through the wound. Similarly, the tension you apply to the wound as you pull the suture through is capable of causing damage. As such, slowly passing the suture through the wound without tension is the best strategy to avoid iatrogenic tissue damage.

6. Using a suture needle that is much larger than the suture thread has potential of introducing puncture wounds that are not filled by the thread and expose the wound to bacterial contamination. A 7-0 suture is the approximately the same thickness as a human hair and it takes exceptional manufacturing to produce a needle of similar size that withstands the challenges of suturing in the oral environment. If the thin needle is weak it will bend easily when it comes into contact with bone or tooth, and if it is too thick, it will create a hole in the tissue that can compromise the surgical site.

7. In medicine and dentistry, the surgeon often finds the myriad of suture choices overwhelming and confusing. What is unique to the oral cavity is that we are dealing with small anatomical structures that are very tough and stiff. It is best to keep things as simple as possible and limit your inventory to a few different types. In periodontal surgery, I use 5-0, 6-0 and 7-0 sutures, with only two types of needles, a short needle for anterior teeth and releasing incisions (12 or 13 mm) and a longer needle for posterior teeth (15 mm). Absorbable sutures are used infrequently as control over when the suture is removed is very important in preventing a premature wound opening and the breakdown products of some absorbable sutures can interfere with wound healing. Monofilaments are the thread of choice in periodontal micro-surgery, as they have low friction, high glide, and produce lower temperatures when passing through tissues. Furthermore there are no cavities and minimal bacterial colonization around monofilament sutures. The disadvantages are that the knots are more likely to come undone if not tied properly; the crimped areas of suture should not be used in critical positions around the wound. Monofilaments are generally weaker in tensile strength than equally sectioned multifilament sutures.

8.Ideal suture characteristics. The ideal suture characteristics are the same in medicine and dentistry. The ideal suture should be as follows:
• Sterile
• All-purpose
• Cause no tissue injury or tissue reaction
• Easy to handle
• Holds securely when knotted
• High tensile strength Resistant to infection
• Easily visible to the surgeon
• Offer predictable performance
• The needle stays sharp and keeps its shape
• The needle is the same diameter as the thread
• Inexpensive
• If absorbable, a predictable absorption time and no inflammatory breakdown products are ideal

9.Wound stabilization takes time. Functional integrity of the wound is not achieved before two weeks. This means the wound integrity largely relies on the stabilization of the flap through suture material and technique. Detachment of the mature fibrin-coagulum from the root surface because of insufficient stabilization jeopardizes periodontal wound healing and regeneration. As such, leaving the sutures in for two weeks is recommended. If we examine the medical protocol, sutures are left much longer than this when a femoral artery or aorta are sutured, as the suture removal appointment would become a major event!

10.Peculiarities of Periodontal Wound Healing. Much more complex than a simple skin injury, McCullogh described periodontal wound healing as the “most complex healing process” in the human body (1993, Periodontolgy 2000). If we look at the mucogingival flap sandwiching an instrumented root surface that had its periodontal attachment removed it is amazing it heals at all. The wound margins are broken by a rigid, mineralized, non-vascular root surface in an open system. The wound includes tissue resources from alveolar bone, periodontal ligament, gingiva, epithelium and cementum that facilitate healing. Wound healing is a formidable process.

11.The suturing is your signature. In medicine and dentistry, the patients, or your peers, are unable to see beneath the surgical wound you have just sutured together. How you have chosen to close the wound becomes your signature on the patient’s body. The patient will invariably examine your signature and judge you on it. A precise and proper wound closure signals to the patient that their surgeon has performed well, whereas a slapdash wound closure is an excellent predictor of a failed outcome, which is readily apparent to most patients.OH

 Peter Fritz is a certified specialist in Periodontics and is in full-time private practice in Fonthill, Ontario. The focus of his periodontal practice is dental implant therapy, bone and soft tissue reconstruction, and oral medicine. Dr. Fritz is an Adjunct Professor in the Faculty of Applied Health Sciences at Brock University.

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