SOFT-TISSUE MANAGEMENT for Surgical Implant Dentistry

 SOFT-TISSUE MANAGEMENT 

1. Flap Design and Handling. Factors to be considered in flap design include the following: access for instrumentation, maintenance of blood supply, preservation of tissue topography, allowance for identification of vital structures, and providing for closure. There are numerous variations in flap designs that will be dictated by the number of implants to be placed and the surrounding anatomical structures. Currently, crestal incisions are usually employed. Envelope flaps are routinely used with and without papillary sparing incision to provide access for limited areas to receive implants (Figure 4). Incisions should score the bone, thereby incising the periosteum when elevating a full thickness flap. 

Figure 4. Papilla sparing incision leaves 1.0 mm of the papilla adjacent to the tooth.

     For the fully edentulous mandible, crestal posterior and midline vertical releasing incisions are sometimes employed to provide access. In the edentulous maxilla, similar incisions can be made. Some clinicians move the crestal incision labially around the incisive papilla to avoid transecting the contents of the nasopalatine canal. Alternately, vertical releasing incisions can be made distal to the canal region and posteriorly as needed. However, it should be noted that an incision through the canal region does not usually have a detrimental affect. 
Flaps should be hydrated periodically so they do not become desiccated. After a long procedure, hydrate the flap and stretch it out. When one tooth is being treated, extend the flap as much as necessary to provide adequate access for surgery. Frequently, when employing an envelope flap, there is a need to include an additional papilla beyond the tooth adjacent to the site being treated to achieve tension-free access and avoid tearing the flap. If treating a deep periodontal defect (eg, 8 mm) on a single tooth, an envelope flap across 3 teeth will rarely provide adequate access. Extend the envelope flap one tooth distal or mesial to the defect being treated and create a vertical releasing incision. There are no elastic fibers in gingiva, so the incision line will heal without scarring.
     2. Using Periosteal Elevators and Suctioning. Place an elevator to the desired depth and make sure it is underneath the periosteum on bone. There are several techniques that can be employed when using a periosteal elevator: rotate clockwise, then counterclockwise; vertical elevation, wiggle out and in; move along the incision line. Other ideas with respect to using a periosteal elevator are listed. When elevating thin tissue, use the thumb to oppose the reflection—this helps avoid tissue tears. It is useful to sharpen periosteal elevators. Have the assistant retract the flap with the periosteal elevator during surgical procedures to avoid operator fatigue. It is beneficial when working with one assistant to create sufficient reflection to permit him or her to retract the flap with the high-speed suction tip. This frees up the assistant’s other hand to handle instruments, etc.

Figure 5. Tying flaps back can improve visibility during surgical procedures.

After flaps are elevated, the elevator should always remain on the bone, because if it compresses, the tissue there will experience increased postoperative swelling. In addition, have the assistant suction the bone; if the tissue is suctioned, there will be increased edema. Suctioning should be done in a sweeping motion, because when the suction tip pokes at the tissue, it can pick up the mucosa and not function efficiently.
     3. Tying Flaps Back To Increase Visibility. In the beginning of a procedure, restraining flaps to enhance visibility takes an extra few minutes, but it can be worthwhile with regard to saving time and facilitating access (Figure 5). If both sides of the arch are simultaneously being treated, tie the lingual flaps to each other. When only one side is surgerized, secure the lingual flap to the teeth on the other side of the same arch. Sometimes it also is beneficial to fix the buccal flap to the cheek. Another technique is to tie the flap to itself. For example, on the lingual, loop through the mesial of the flap (buccal to lingual) and tie it to the distal of the flap (lingual to buccal) and pull it tight. The tension created by the sutures keeps the tissue reflected.
     4. Suturing and Surgical Knots. As a general rule, suture movable tissue to fixed tissue rather than fixed tissue to loose tissue. Snug sutures down, but do not tie them tight, because tension can result in pressure necrosis, and the sutures may tear through the tissues.⁷ When suturing, the needle should engage 2 to 3 mm of tissue, and sutures should be placed every 3 to 5 mm along the incision line. Leave ears of 2 to 3 mm long after cutting the suture or it may unravel. A surgeon’s knot is usually all that is necessary to close an incision line (2 ties clockwise and one tie counterclockwise). When synthetic or naturally resorbing sutures are used, the clinician can add another clockwise knot to prevent unraveling. Note that additional ties do not add to the strength of a correctly tied knot—they only add to its bulk. Tie all the knots on the same side of the incision line. When tightening a knot, pull in a direction parallel to the incision line, not perpendicular to it. Final tension of final throw should be as nearly horizontal as possible. A sling suture (lasso) around the implant will pull the flap tightly around the implant. When selecting a suture material, keep in mind how long tensile strength lasts for different types of suture materials: plain gut (7 to 10 days), chromic gut (10 to 14 days), and Vicryl (40% at 21 days).

Figure 6. Diagram showing how to close a T-vertical releasing incision.

When closing a vertical releasing incision and the fixed tissue is thin, before trying to suture, slightly raise the fixed tissue with an elevator so that the suture needle can fit through the tissue without tearing it. To close a vertical releasing incision distal to the osteotomy site (T-shaped incision), use a figure-8 or criss-cross suture as follows (Figure 6). At the distal of the crestal (horizontal) incision, engage the buccal aspect of the horizontal flap, then cross the vertical incision line and enter the fixed tissue on the distolingual and knot it. Do not cut the suture yet. Now engage the buccal aspect of the fixed tissue distal to the vertical releasing incision and suture this to the distolingual aspect of the movable flap across the vertical incision and tie a knot. The figure-8 suture will pull the T releasing incision together. If desired, a figure-8 suture can also be used over an extraction site to draw the margins of the gingiva towards each other. 
     Over a barrier membrane, there is an increased tendency to observe tissue dehiscences. To help avoid this, place horizontal mattress sutures using an absorbable suture (eg, Vicryl). Then reinforce these sutures with interrupted sutures. Conceptually, the mattress suture provides additional strength to resist muscle pull (eg, buccinator or mentalis muscle). However, suture technique is not a substitute for appropriate flap release and passivity of closure. After an incision is sutured, use wet gauze to compress the flap, and then take a probe to check to see that the flap is well coapted (gently brush the probe across the suture line to find sections of tissue not engaged well). 

     5. Critical Factors Affecting Papilla Height in the Aesthetic Zone. After a surgical procedure, if the distance between the osseous crest to the contact point between teeth is < 5 mm, the papilla will usually return (98% of the time). When the distance is 6 or 7 mm, the chance of the papilla filling the embrasure is, respectively, 56% and 27%. According to Garber et al, in the aesthetic zone, the height of the average papilla that forms adjacent to an implant is dependent on the type of restoration adjacent to the implant (Table). The determining factor for papilla height adjacent to a single implant is based on the interproximal bone height of the adjacent tooth. This is true even if there is severe bone loss on the tooth to be extracted. Accordingly, before implant placement, the sulcus of the adjacent tooth needs to be probed to predict future papillary height. The supracrestal fibers of the adjacent tooth maintain the papillary height. On the day of insertion of a single implant crown in an edentulous space, the papilla will not completely fill the embrasure 90% of the time, because after an extraction, the papilla recedes. However, within one year, 80% of the interdental spaces will be filled.

Figure 8. Short papilla between implants at sites Nos. 5 and 6. Average height of the papilla between implants is 3.4 mm.

     After an extraction, it doesn’t matter if an edentulous area is temporarily restored with or without a flipper; the col area shrinks and becomes keratinized. Subsequently, after an implant and a temporary crown are placed, the papilla and its col reform (Figures 7a and 7b). On the other hand, if an implant is placed into an extraction site and is immediately provisionalized, it helps maintain the papillary form and height. It also has been noted that if a healing abutment is not removed after initially being placed, there will be less recession, because the junctional epithelium was not disturbed. With respect to the final aesthetic outcome, it does not matter if a flipper or a temporary crown are immediately used, since the attachment level on the adjacent natural teeth determine the final papillary height.
     Between dental implants the average height of the papilla is 3.4 mm (Figure 8).14 According to Tarnow, et al, the papilla between implants will attain the following heights (crest of bone to contact point): 2, 3, 4, and 5 mm, respectively, 16.9%, 34.7%, 37.9%, and 5.6% of the time. Ninety percent of the papilla will be between 2 to 4 mm in height. The reduction of papillary height compared to natural teeth is due to the absence of supracrestal gingival fibers.

     Based on the above information, the following conclusions can be drawn to with respect to maximizing anterior aesthetics. If there is a choice with respect to which sites can be used for implants to replace missing maxillary anterior teeth (eg, Nos. 7 to 10), it will be more aesthetic if 2 implants are not placed next to each other, since a short papilla will develop. It would be preferable to place implants at sites Nos. 7 and 10, or Nos. 7 and 9, or Nos. 8 and 10 (Figures 9a to 9c). If only 2 adjacent teeth are missing, consider placing one implant and a cantilever. In addition, for an optimum aesthetic result, it is preferable to use an ovate pontic. Sometimes it will be necessary to place a connective tissue graft to augment the soft tissue under the ovate pontic. If Nos. 8 and 9 are the 2 adjacent teeth that are missing, 2 implants can be placed, and an aesthetic result can be attained by lengthening the contact area in the midline. The real difficulty arises when Nos. 7 and 8 or Nos. 9 and 10 are the adjacent missing teeth, because this will result in asymmetry with respect to the papillary heights on the contralateral side.