What is it?
The Free Gingival Graft (FGG) is a surgical procedure frequently used in periodontics to increase the amount of keratinized tissue surrounding a tooth or a dental implant. Keratinized tissue plays a major role around teeth and dental implants, helping in maintaining and facilitating oral hygiene. This surgical technique was originally introduced in 1966, by Dr. Nabers. The process involved in the healing of this type of gingival graft was further described by the extensive work of Drs. Sullivan and Atkins (oral presentation 1967, in print 1968). Originally, the indications for use of this technique were the most varied. Nowadays, it sums up to a just a few:
Indications for Free Gingival Graft
- Increase of keratinized tissue adjacent to teeth, dental implants or edentulous ridges (the only graft).
- Coverage of certain type of gingival (gum) recessions.
Other surgical techniques (i.e. coronally advanced flap) provide a better esthetic outcome for root coverage procedures. However, this remain a viable option for those cases in which localized factors (such as a frenum) might not allow the direct execution of a coronally advanced flap.
Contraindications for Free Gingival Graft
- Need for an intraoral donor site (a second surgical site).
- High esthetic demand.
The major limitation to the use of the FGG technique is the need for a donor site. Most commonly the tissue is harvested from the palate (the roof of the mouth), but also from edentulous sites (areas with no teeth) or from the maxillary tuberosity (an area behind the last top molar tooth). The second surgical site may increase the length of the procedure, as well as post-operative discomfort. The discomfort can be reduced protecting the area with a stent or a periodontal dressing. I like to use a vacumform stent. To fabricate the stent I use a thermoplastic material, that is vacuum-pressed on the pre-operative dental cast. With this technique I can provide the patient with a thin appliance, that fit tightly and does not alter too much the speech. Periodontal dressing (i.e. Coe-Pack, GC) can also be used, but is more likely to be dislodge during the immediate post-operative days, leaving the patient with an exposed wound.
The esthetic result of the free gingival graft technique can range from very poor to excellent, depending on tissue characteristics proper of each patient. As this is not always predictable, I tend not to use this technique in patient demanding an excellent esthetic outcome. However, a modification to the original technique, recently published by Dr. Cortellini and colleagues (partly epithelialized free gingival graft, 2012), seems to overcome most of the aforementioned limitations.
Step 1 – Proper Diagnosis
The anterior mandibular area presents minimal keratinized tissue and generalized recessions (Miller Class II-III). The mandibular median frenum is ulcerated due to toothbrushing trauma. The patient was instructed in proper oral hygiene techniques, however no improvement was noted and the patient reported discomfort while brushing. The surgical plan consisted in removal of the mandibular median frenum and increase of the keratinized tissue, in order to facilitate oral hygiene.
Step 2 – Preparation of a Mucosal Bed
The recipient site is prepared. A mucosal (split-thickness) flap is elevated and reflected past the mucogingival junction. A periosteal bed is left on the recipient site to facilitate suturing. Muscle insertions are completely released (this is critical if we want to achieve attached gingiva).
Step 3 – Harvest the Graft
The gingival graft is harvested from the donor site, in this case the palate (roof of the mouth). Hemosthasis (blod clot) is achieved applying pressure with a sterile gauze. The palate allows to harvest graft of approximately 15-20mm in length and 5-15mm in height, depending on the anatomical characteristics of the palate. The graft is normally harvested from the first molar – canine area. A band of 2-3mm of tissue (>3mm may be required, depending on pocket probing depth) is left around the gingival margin of the teeth, to avoid recession. Injuries to the greater palatine artery do not happen frequently, however the risk exists. In this case prevention is the best medicine, carefully assess the anatomy of the area. The average distance CEJ (first molar) – greater palatine artery is ~13mm (Fu et al 2011), however this change considerably with the anatomy of the palate. A good general principle is: shallow palate – 7mm, medium palate – 12mm, high palate – 17mm (Reiser et al 1996).
Step 4 – Graft Preparation
The gingival graft is harvested 15-25% larger than the desired final size. This to overcome primary (immediate) and secondary (during healing) contraction. A thin graft will have less primary,but more secondary contraction. A thick gingival graft will have more primary and less secondary contraction. The graft can be expected to shrink an average of ~20% during healing. The graft harvested from the palate are normally rectangular in shape, the subepithelial tissue is mostly composed by a thin connective tissue layer, adipose and glandular tissue. Adipose and glandular tissue should be removed from the connective tissue surface of the graft, before placement on the recipient site. This procedure can be easily accomplished using a new #15 blade.
The free gingival graft can be harvested from alternative sites, such as: edentulous areas, buccal areas, or the maxillary tuberosity (as in the above image).
The free gingival grafts harvested from the maxillary tuberosity area have a trapezoidal shape, with the major base showing a more or less pronounced concavity. This type of graft is composed by a thin epithelium supported by a thick fibrous connective tissue. Glandular or fat tissues are normally not present in this area. The size of the maxillary tuberosity varies considerably from patient to patient. The average size of this graft is ~7x10mm.
Step 5- Suture, Suture, Suture
The free gingival graft is finally sutured in place, with a combination of resorbable and non-resorbable sutures. Anchoring periosteal sutures or metal tacks can be used to further stabilize the graft. Absolute immobilization of the graft is the key factor for the success of this procedure. The mucosal flap reflected on the recipient site, can be sutured apical to the graft, or removed (scissors work better than a blade for this operation). The recipient and donor sites are normally covered with a protective stent or a periodontal dressing.
It Works Great With Dental Implants
Sometimes it might be required to increase the width of keratinized mucosa around one or more dental implants. In this cases, the free gingival graft technique is very effective. In fact, with one procedure you can achieve two purposes: vestibular extension (creating more space to fit the toothbrush) and increased of attached keratinized mucosa.More info about the author: Alessandro Geminiani, DDS, MSc, MS is a specialist in periodontics and dental implants. His practice focuses on free gingival graft (gum graft) and is located in Rochester, NY.