The Apical Gingival Displacement Technique

With the osseous resorption that is observed following extraction, it is not unusual for the band of keratinized tissue to decrease in size as well. This may also occur in some sites where extraction is planned for immediate implant placement. Identification of the need for an increased band of keratinized gingiva when planning an implant's placement can help to avoid maintenance issues following its restoration. Apical gingival displacement is a simple technique that can be used to increase the band of keratinized gingiva without the need for other more complex techniques, such as soft-tissue augmentation.

When a planned implant site presents with insufficient keratinized tissue on the buccal/facial aspects, the use of a two-stage implant surgical approach can facilitate an increase in the size of the band when the implant is uncovered at the outset of the restorative phase. This approach may also be utilized when immediately placing an implant into an extraction site or, with some modification, when placing an implant into a healed extraction site.

Typically, with immediate implant placement, a healing abutment is placed into the implant to help develop a proper soft-tissue emergence profile. However, when an increase in keratinized gingiva is sought, use of a flat cover screw or narrower healing abutment is suggested in place of a full-size healing abutment. During the initial period of healing, this will allow the soft-tissue growth to cover the crestal area where the extracted tooth emerged. Keratinization will occur after the gingiva has covered over the crest. When it is time to uncover the implant, the apical gingival displacement technique can be used with the crestal incision being made more lingually, which allows the soft tissue to be displaced buccally and held in its new position by a healing abutment, increasing the thickness of the desired band of keratinized gingiva.

When an implant is to be placed into a healed extraction site, identification of an inadequate band of keratinized tissue needs to be made prior to placement (Figure 1). The band is measured from the crestal-buccal line angle. The volume of attached tissue is accessed using a standard mucogingival mapping technique, in which the mucosa is stretched or rolled to identify the mucogingival junction. If the band is greater than 3 mm from the crestal-buccal line angle to the mucogingival junction, then sufficient keratinized tissue is present, and a tissue punch may be used. When the band is 3 mm or less, increasing the band is required.

Local anesthetic is administered to the tissues, including the papilla on either side of the site being uncovered. Typically, local infiltration is sufficient for use of the apical gingival displacement technique because minimal tissue manipulation will be performed. Using a No. 15C scalpel blade, an incision is made at the line angle where the crest meets the lingual aspect of the ridge as illustrated by the blue line that can be seen in Figure 2. The incision contacts the teeth on either side of the implant site, and once the tissue is elevated, it will reposition (ie, displace) the papilla buccally. A periosteal elevator (No. 9 Molt Periosteal, Hu-Friedy) is placed under the buccal aspect of the incision, and a full thickness mucoperiosteal flap is elevated to the mucogingival junction. After the implant is placed using a guided procedure, a healing abutment with sufficient height is placed into the implant so that it extends at least 2 mm above the soft tissue to hold it in place (Figure 3). The diameter of the healing abutment should be selected with the emergence profile in mind. If desired by the practitioner, a custom emergence profile abutment may be used at this stage to develop a natural-looking emergence profile, allowing all of the soft-tissue healing to occur during the same period, readying the site for impressions. Selection of a wider healing abutment can also help to displace the buccal flap further apically, providing an even greater band of keratinized tissue.

The healing abutment is placed in a manner that holds the buccal tissue in its new apical position. Sutures are not needed or required. Wet gauze is applied to the soft tissue with light pressure until any marginal bleeding has stopped. Depending on the patient and if he or she is on any anticoagulants, this can typically take from 5 to 20 minutes. The pressure created from the finger tacking down the displaced tissue forms a fibrin clot, and then the healing abutment maintains the tissue in its new position throughout the initial healing period. The exposed area at the papilla where the incision presents mesially and distally to the healing abutment will fill in by secondary intention and result in dense keratinized gingival tissue surrounding the healing abutment (Figure 4). Following a 3- to 4-month implant integration period, the crestal tissue has filled in the incision, an improved band of keratinized tissue has resulted, and the site is ready for impressions (Figure 5).

A 72-year-old female patient presented for implant placement in her lower right first molar site following guided planning for the implant's position. In this case, it appeared that there was an insufficient amount of buccal keratinized tissue present (Figure 6 and Figure 7), and the mucogingival junction was tested to confirm the initial observation (Figure 8). Following local anesthetic application (HSI Lidocaine HCL 2% w/epinephrine 1:100,000, Henry Schein), an incision was made to the lingual aspect of the midline of the crest, and the buccal tissue was elevated and displaced apically. After a guided surgical approach was performed to place the implant at the site (Tapered Plus dental implant, BioHorizons), a healing abutment was placed into the implant to maintain the soft tissue in its new position during healing, and the patient was dismissed (Figure 9).

Three months later, the patient returned for the initiation of the restorative phase. After the healing abutment was removed and an open tray implant impression was taken, the healing abutment was reinserted, and the impressions were sent to the laboratory for fabrication of a screw-retained restoration. The laboratory modified the soft-tissue on the model to develop an ideal emergence profile, and the zirconia screw-retained restoration was fabricated and returned to the office for insertion (Figure 10).

A local anesthetic (HSI Lidocaine HCL 2% w/epinephrine 1:100,000, Henry Schein) was applied to the papilla on both sides of the healing abutment, and an incision was made into the mesial and distal aspects at the midpapilla to allow the tissue to further stretch to accommodate full seating of the screw-retained restoration (Figure 11). Once it was inserted, a radiograph was taken to verify that it was properly seated. The emergence profile provided a natural-looking appearance that mimicked that of a natural tooth (Figure 12 and Figure 13).

Sufficient keratinized gingiva surrounding an implant restoration's emergence has been recognized as important to the long-term success and maintenance of implants. Frequently, a loss of keratinized tissue width occurs following the extraction of a tooth, and this loss can increase when the period of time prior to implant placement is increased. This loss of keratinized tissue is typically confined to the buccal aspect of the ridge due to its dimensions, which are naturally narrower than those of the lingual aspect of the ridge.

Traditionally, connective tissue grafts have been the go-to method of increasing the band of keratinized buccal tissue. However, this approach increases treatment costs and postoperative patient discomfort and may require a separate surgery with increased treatment time before the restoration is completed. The apical gingival displacement technique facilitates preservation of the keratinized gingiva at the crest of the ridge and permits repositioning to the buccal aspect of the ridge to yield an adequate band, improving gingival stability around the implant restoration, shortening the treatment time that would normally be required with a connective tissue graft, and improving the patient's postoperative comfort because an oral donor site to acquire a connective tissue graft is not required.

The apical gingival displacement technique is suited for implant placement in sites with insufficient keratinized tissue when a one-stage surgical procedure is planned that will utilize a healing abutment to hold the tissue in its new position. It can also be used when inadequate keratinized tissue has been noted in a two-stage procedure to uncover a previously placed implant and initiate the restorative phase.

Robert J. Stanley, DDS, MS, PhD
Diplomate
American Board of Oral Implantology

Diplomate
International Congress of Oral Implantologists

Private Practice
Cary, North Carolina

Gregori M. Kurtzman, DDS
Master
Academy of General Dentistry

Diplomate
International Congress of Oral Implantologists

Private Practice
Silver Spring, Maryland