April 1, 2012
by Michael Dib, DMD, MSD, FRCD (C)
Gingival recession is defined as tissue breakdown that results in exposure of the root surface. Recession is considered a mucogingival condition because it can lead to numerous periodontal concerns. The main consequences of gingival recessions are: root sensitivity, increased risk of root decay, esthetic concerns, loss of periodontal support. The dental community has always tried to establish effective techniques to treat such gingival deformities. The esthetic area is often defined as the labial of teeth #14 to 24. For some clinicians, the esthetic zone varies with each patient and should be defined as the buccal area of all maxillary teeth with visible gingival margin. For the sake of discussion in this article, we will use the first definition. The main goal of gingival grafting in the esthetic zone is to obtain root coverage. Different methods have been developed through the decades, some more successful than others.
Before undertaking a grafting procedure, every clinician should first assess the cause of the recession. By identifying the cause and establishing a proper diagnosis, the operator will increase the success rate. With adequate pre-operative preparation, a clinician should be able to predict the end result of each procedure.
The first step is to establish the right diagnosis. Generally, there are two types of gingival recession: visible and hidden.
1) Visible recession is defined as the clinically observable root measured from the CEJ to the margin of the gingiva.
2)Hidden recession is the depth of the sulcus (or pocket) as measured from the margin of the gingiva to the junctional epithelium. This is an important aspect to determine before performing gingival grafting. At the initial consultation, clinicians should probe the buccal area to measure the hidden recession. For example, let’s examine a tooth with a visible recession of 4mm and a hidden recession of 3mm (Fig. 1). This tooth has a combined recession of 7mm. This measure is vital in determining the size of the graft to be used. Because a part of the vacularization comes from the underlying bone, the amount of recession tells us how far apical the bone is situated. Measuring the hidden recession also allows us to avoid surprises. A deep periodontal pocket can often go unnoticed until the flap is elevated.
CRITERIA FOR SUCCESSFUL ROOT COVERAGE
Clinicians should be able to assess and accurately predict the outcomes of their procedures. At the initial examination, the operator should tell the patient if complete root coverage is anticipated. The patient can then decide if they want to go forward with the surgery. In order to project what the end result will be, some clinical factors need to be evaluated. First and foremost, the interproximal bone level should always be assessed. It will be difficult, almost impossible, to achieve 100% root coverage if there is loss of interproximal bone (Fig. 2). The underlying bone is an important source of blood supply.
The amount of attached gingiva present pre-surgically should be measured. The presence of a band of attached gingiva means that the coronal part of the flap will have a keratinized margin. This will make it easier to suture and therefore pull on the flap to ensure complete coverage of the graft. In the absence of this band of attached gingiva, the operator will be suturing in the mucosal tissue, which can lead to tearing of the flap (Fig. 3).
Furthermore, having marginal attached/keratinized tissue won’t guarentee success unless the tissue has adequate thickness. A good rule to follow is to ensure that the marginal tissue thickness is at least 1mm. Thin marginal gingiva might not survive when pulled over the graft, and could slough, leaving the graft exposed. This is more critical when using an allogenic graft, because these grafts should typically be completely covered by the flap to avoid infections. Figure 4 desmonstrates tissue necrosis over an allogenic graft. The flap thickness was minimal, which led to tissue sloughing.
Through the years, different root coverage techniques have been developed. The most often used techniques today include: tunnel, coronally positioned flap, lateral pedicle flap, and double papilla. The first two techniques will be discussed since they are the most widely used ones. The tunnel technique is often the primary choice for root coverage because of the minimal postoperative problems. This technique allows the operator to insert the graft into place without having to elevate the papillae. By leaving the papillae attached, the clinician will considerably reduce the amount of tissue retraction (Fig. 5). Because the tissue is undermined instead of being elevated, there is almost no postoperative swelling. By minimizing the swelling, the operator increases the chances of obtaining complete root coverage. The main limitation of this technique is that it cannot allow for maximum coronal advancement of the tissue to cover the graft because the papillae are left attached.
The coronally positioned flap requires incising through the papillae complex. This allows the clinician to be able to elevate the papillae and facilitate graft insertion. The main advantage of this technique is to allow maximum coronal advancement of the flap to cover as much of the exposed roots as possible (Fig. 7). One of the main disadvantages is increased postoperative swelling and discomfort when compared to the less invasive tunnel technique. In order to properly achieve coronal positioning of the flap, the papillae bed must be de-epithelialized to allow the flap to lie down on a connective tissue bed (Fig. 8).
Suturing is a critical part of every grafting procedure. Despite what most clinicians might think, the types of sutures used are not as important as the technique utilized. However, for the sake of discussion, the gingival graft should preferably be sutured with a long absorbable material, such as polyglycolic acid (PGA). The overlying flap/pouch should be sutured with a nonabsorbable material, such as polypropylene. The graft should be sutured in a way that it rests over the root surface without any mobility. The overlying flap/pouch should be sutured coronally and passively to cover the graft. The flap can also be pulled about 1 millimeter coronal to the CEJ. There must not be any tension when the flap is advanced coronally. If too much tension is created while suturing the flap, the gingival tissue can undergo necrosis. Sloughing of the flap will expose the graft and diminish the success rate. The best way to ensure tension-free advancement of the flap is to utilize a split-thickness flap. In areas where additional release is needed, a superficial split-thickness flap should be utilized. This technique was pioneered by Dr. Henry Greenwell and allows for maximum flap release. A continuous sling suture technique is privileged because it allows the clinician to apply an even and constant amount of pull over the entire grafting area (Figs. 9-10). The continuous sling can be applied to both the graft and flap suturing.
The main reason to prescribe medications is to reduce the post-operative swelling and discomfort. Another goal is to prevent infections. Different drug regimens can be prescribed, and it ultimately depends on the technique used, as well as clinician preferences. In most cases, a combination of an anti-inflammatory, an antibiotic, and an anti-bacterial mouthwash will be given. In situations where multiple teeth have been grafted and the clinician expects a lot of swelling, a corticosteroid can be recommended to help prevent flap retraction from over the graft. The suturing technique and flap manipulation are the most important factors to consider. If the surgical technique used is not adequate, no medication will save you from a failure. The sutures are typically left in place for three weeks. Early removal of sutures can
displace an immature graft and cause failure. Patients should be advised not to brush the area for up to three weeks. As of the second week, the patient can start cleaning the area by gently applying chlorhexidine locally with a cotton swab. Every root coverage case should be followed for up to six months to make sure the healing is complete. Finally, a good oral hygiene is of the outmost importance to ensure great results.OH
Michael Dib, DMD, MSD, FRCD (C), Diplomate of the American Board of Periodontology.
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