Introduction
A suture is any strand of material used to ligate blood vessels or approximate tissues. It consists of a thread material which is attached to a needle. The use of suturing has been documented as far back as 2000 B.C. by Egyptians. Today many see suturing as an art form in surgery. Dentists and surgeons alike should have a thorough understanding of the design of the equipment and materials they are using.
In dentistry, sutures are routinely used to achieve haemostasis, approximate tissues after extraction, implant surgeries, periodontal surgeries and biopsy procedures. Intra-orally most wounds heal by secondary intention which can delay the healing process and this can manifest clinically as symptomatic issues for patients. Suturing makes it possible to strive towards healing by primary intention. Suturing can also act as an adjunct to treatment, for example in periodontal crown lengthening surgery the primary aim is to remove excess tissue via incisions but the type of suturing can help reposition the tissues more apically.
This article aims to inform the reader of types of suture needles, suture materials and techniques which will provide an insight into material selection and overall better treatment outcomes based on a more educated approach.
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Approximate wound edges to maximise healing by primary intention |
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To cover bone as much as possible to prevent bone necrosis |
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Hold the flap in the desired position |
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To aid in soft tissue haemostasis |
Table 1, Aims of suturing
The Anatomy of a Needle
:
The Point
The point extends from the tip of the needle to the maximum cross-section of the needle body.
The Body
This is the portion of the needle that is held by the needle holder while suturing. The body diameter should match that of the suture material as closely as possible to bleeding and leakage. The shape of the body can vary greatly ranging from straight to fish-hook-shaped. Curved needles require less space for manoeuvring compared to a straight needle. Most commonly in dentistry, the curvature of the body is designed around a circle, typically these are 3/8 circle, 1/2 circle and 5/8 circle.
The Eye
There are three categories that the eye of a needle can fall into the closed eye, French or swaged (eyeless). The majority of needles used in surgery are swaged. With this configuration the needle and suture form one continuous unit which minimizes tissue trauma.
- Point
- Body
- Eye
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Figure 1, Diagram of a suture needle
Needle Types
Conventional Cutting
This needle type has three cutting edges, the third being on the inside of the curvature of the needle. This type of needle may be prone to cutting out of tissue because the
inside
cutting edge cuts towards the edges of the incision.
Reverse Cutting
These needles were created for tough, difficult-to-penetrate tissue such as skin and oral mucosa. This needle is as sharp as the conventional cutting needle but its design is slightly different. The third edge is located on the
outer
convex curvature of the needle. This offers several advantages such as:
Reverse cutting needles have more strength than conventional cutting needles
The danger of tissue tearing is greatly reduced
The hole left by the needle leaves a wide wall of tissue for the suture to rest against while the suture is tied.
Taper-Point
Taper-point needles pierce and spread tissue without cutting it. The needle point tapers to a sharp point. The needle body flattens to an oval or rectangular shape. They are preferred when the smallest possible hole in the tissue and when minimum tissue cutting is desired.
Taper-Cutting
This needle combines the features of both the reverse cutting edge tip and taper point needles. The cutting edge extends slightly from the point and then blend into a round body. All three cutting edges are typically sharp to provide a uniform cutting action. The point (aka trocar) readily penetrates tough tissues.
The point diameter should not exceed that of the suture
The tapered body provides smooth passage through tissue.
Figure 2, Types of needles
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1. High uniform tensile strength, permitting the use of finer sizes. |
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2. High tensile strength retention in vivo, holding the wound securely throughout the critical healing period, followed by rapid absorption. |
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3. Consistent uniform diameter. |
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4. Sterile. |
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5. Pliable for ease of handling and knot security. |
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6. Freedom from irritating substances or impurities for optimum tissue acceptance. |
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7. Predictable performance. |
Table 2, Suture material Qualities
Figure 3, suture classification
Figure 4, Monofilament suture Figure 5, multifilament suture
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Absorbable |
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Table 3, Suture types
Suture Materials
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Material |
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