VN November 2021

Vetnuus | November 2021 32 Placing sutures in the oral cavity of dogs and cats is commonly performed daily by veterinarians. This column will look at some matters you should consider in choosing the suitable suture material to close your flap or repair a defect created during surgery. The holding strength of the tissue Tissue strength is dependent on the amount of collagen and the orientation of these fibres in the tissue. [1] The strength of the suture used should be at least as strong as the tissue it needs to close. The time that the suture will take to dissolve It is essential to use a suture material that will maintain most of its strength for the period as the tissues take to heal. Suture material should also not be retained longer than necessary as it is a foreign object. The longer it stays in the tissue, the more likely it is to have complications such as infection and inflammation. The healing time of the tissue as well as local tissue factors Oral mucosa heals relatively quick, ranging from 14 to 21 days. [2] The appropriate suture material should therefore lose its tensile strength in the same period. Local tissue factors such as infection may result in quicker absorption (variable absorption times) of suture material (e.g., uncoated catgut). Therefore, it will be safer to use synthetic suture material with a predictable absorption time compromised tissue. Adequate size of the suture material The smaller the size of the suture material, the less the trauma and the smaller the knots will be in the oral cavity. Minor tissue trauma will result in less inflammation and much quicker healing. Smaller knots will cause less irritation in the mouth and will harbour fewer bacteria than big bulky knots. In most circumstances, a size 4/0 will be adequate for suturing in a dog’s oral cavity, while a 5/0 will be adequate for cats and toy breed dogs. Tissue and suture handling Atraumatic handling of the tissues will result in less inflammation and quicker healing. Using an Adson tissue forceps causes less tissue damage in comparison to a tissue crushing forceps (Adson- Brown tissue forceps). Sutures should be handled with care and should not be clamped with the forceps or the needle holder as this can damage/weaken the material, which can cause it to break. Surgeon’s preference The surgeons’ preference may play a minor role. Still, it should always be secondary to the selection of the suture material based on the characteristics of the suture material and the tissue factors. Suture classification Suture material can be classified into the following categories: absorbable and non-absorbable, monofilament and multifilament, and whether it is made from synthetic or organic material. Absorbable material is generally a better choice for use in the oral cavity. The non-absorbable suture material is quite stiff and uncomfortable in the patient’s mouth, which must be removed later and has no advantage over the use of absorbable suture material. Monofilament suture material causes less tissue drag and minimal tissue reaction. It also harbours fewer bacteria which make it a better choice. The synthetic suture material is absorbed by hydrolysis, while organic/natural suture material is absorbed by enzymatic degradation. Synthetic suture material thus has a more predictable absorption time as hydrolysis does not get significantly affected by local tissue factors such as infection or inflammation. Suture needle The needle can be categorised into swaged on and eyed needles; tapered, reverse cutting, round, and regular cutting needles. Eyed needles are contraindicated for use in the oral cavity as it causes too much trauma when passed through tissues. A reverse cutting bodied needle is generally recommended for use in the oral cavity as this type of needle reduces the risk of pulling the suture material through the edge of the gingival flap. [1] The smallest sized needle possible should be used, but it should still be big enough to pass through both sides of the tissue. With oral surgery, you often work in a confined space, and a ⅜ or ½ circle needle is recommended as this allow the surgeon to pass the needle from the buccal to the lingual surface with one motion. [1] The most commonly used suture material in the oral cavity: • Poliglecaprone 25 ( Monocryl ) or Polyglycolic – co – caprolactone ( Monozyl ) Synthetic, monofilament, absorbable Good knot security, easy to handle, good tensile strength and minimal tissue drag. Only loses tensile strength after 21 days and gets absorbed after 78 days [3] [2] • Polyglactin 910 ( Vicryl ) Synthetic, multifilament, absorbable Fair knot security, easy to handle, very soft and is assumed to cause minimal patient discomfort and irritation afterwards. [3] They do cause a mild tissue reaction. Around 14 days, 35% of tensile strength is lost [3] What suture material to use after an extraction Dental Column Dr. Mareli van de Wetering & Prof. Gerhard Steenkamp