The molars 46 and 47 are to be restored. For there are carious defect of the hard tissue Professor Dr. Hannes Wachtel, Munich/Germany does a preprosthetic treatment. In the vestibular and lingual area of the posterior region of the forth quadrant as well as in the region distal of the terminal tooth the gingiva is apically positioned. While in the buccal area a split thickness flap is needed for the apical positioning, in the lingual area a full thickness flap is appropriate.
Surgical crown lengthening with an apically positioned flap is often needed in order to maintain the biologic width. The restorative margin must not be placed closer than 2 mm to the crestal bone in order to not irritate attachment structure. The surgical procedure of an apically positioned flap is demonstrated by Prof. Dr. Wachtel.
In this case, new restorations are planned in the posterior region of the right mandible. Prior to the restoration, the teeth 46 and 47 will be prepared with an apically positioned flap in the vestibular and lingual region. First, a paramarginal incision is performed on the buccal side following the tooth shape. In the interdental area, the incisions cross each other so that new papilla tips are created parallel to the original ones.
In the next step, Prof. Dr. Wachtel prepares a split flap in the vestibular area. Not removing periosteum from the bone surface is important for the success of this surgery since later the flap needs to be fixed at the periosteum to remain in the intended apical position. In contrary, on the lingual side a full thickness flap is prepared following the paramarginal incision in order to avoid any damage of the lingual artery and nerve. However, due to the anatomy in this region the lingual flap does not move coronally but rather stays in the desired apical position. Following an intrasulcular incision all the tissue within the incision lines as well as excess interdental soft tissue has to be thoroughly removed. In addition, the soft tissue in the distal area of the terminal tooth 47 is reduced with a distal wedge procedure and is placed in a more apical position as well.
Once the mobilization of the buccal and lingual flap is completed, the alveolar bone around the teeth is reduced, reshaped and smoothened using a round diamond burr. The flaps are fixed applying microsurgical sutures, which in the buccal area are guided from the mobile part of the flap through the attached areas of the periosteum. The fixation of the buccal split thickness flap to the underlying periosteum ensures the apical positioning. A connection to the lingual full-thickness flap can be established through the interproximal spaces. In the distal area Gore-Tex sutures are applied.
Finally, the wound is covered with a dressing. After a healing period of about three months the prosthetic restoration of 46 and 47 can be started.