The OBS technique was approved by the ethical committee and the South of France Committee (Agreement CPP Méditerranée N°2014-A0006443). All patients provided written informed consent. The three cases were treated with the OBS technique for implant relocation.
A 46-year-old man, in good general health, with an implant placed 5 years before, wanted to have his maxillary incisor diastema closed (Fig. 3). Clinical and radiological examination showed a correctly osseointegrated implant replacing the right maxillary central incisor and healthy soft tissues. The orthodontic treatment plan goal was to reduce the maxillary and mandibular incisor protrusion and the setup revealed, as the implant could not be moved by orthodontic treatment, a severe malposition without any possibility for a new prosthetic restoration. Esthetic rehabilitation required repositioning or implant removal.
The treatment management was, first, to correct the mandibular incisor protrusion with the avulsion of the right mandibular central incisor, which was necrotic with a very dark enamel. Then, the lower jaw space and the maxillary anterior diastema had to be closed, and finally, the implant had to be relocated or removed.
Orthodontic preparation to close the maxillary incisor diastema and the mandibular extraction space was done with a .018x.025 stainless steel wire (SSW) excluding the implant on the maxilla, and with a .019x.025 SSW in the lower arch.
After teeth alignment, it was confirmed that the position of the implant was unfavorable for a new prosthetic rehabilitation (Fig. 4). Despite good implant osseointegration and an adequate prosthetic crown, an OBS technique was proposed to the patient. Ultrasonic cuts were made on the palatal side for implant relocation with an antero-posterior movement. Immediately after flap closure, orthodontic forces were applied with an elastic chain between the implant and the archwire associated with 4.5 oz. intermaxillary elastics to pull the implant towards the palatal direction (Fig. 5). Elastics were changed by the patient twice a day, and, elastic chain reactivation was performed by the orthodontist, every week in the first month, then every 15 days. After 3 months, the implant crown was aligned with adjacent incisors, and the relocation result was stabilized by 3 additional months with a .021x.025 SSW. (Fig. 6). The prosthetic crown was preserved and a fixed retainer was bonded to the anterior upper arch. At 18 months post-treatment, teeth alignment and esthetic results were stable (Fig. 7).
A 23-year-old man, with an openbite facial pattern tendency, in good general health without any contraindication to surgery, was referred for prosthetic restoration of one implant replacing the central maxillary left incisor. The implant was placed 1 year after the extraction of the ankylosed tooth and was correctly osseointegrated, with healthy soft tissues.
However, implant positioning did not respect gingival line alignment and worsened over time with an excessive labial angulation not permitting a screw-retained restoration. Orthodontic treatment and the OBS technique were indicated to realign the maxillary teeth and to relocate the implant in a good position, compatible with a screw-retained restoration, and to prevent a worsening implant position due to the continuous alveolar growth. A provisional screwed crown was made during the orthodontic preparation for esthetic considerations, but the restoration was too wide and the screw was positioned on the buccal side (Fig. 8).
The orthodontic treatment of the malocclusion was carried out and .021x.025 SSW were placed on both arches with additional hooks on the lower arch (Fig. 9). At the end of the preparation, a new provisional restoration with an anatomical shape and dimension was built in the implant axis according to the final realization. The maxillary archwire was adapted, allowing the insertion of the new provisional screwed crown in the implant axis to evaluate the real wrong position of the implant and for movement guidance during the orthodontic implant traction. (Fig. 10).
During surgery, only one horizontal incision was made in the keratinized gingiva, allowing papillae preservation and a full-thickness mucoperiosteal flap elevation on the buccal site. Two vertical deep ultrasonic corticotomies, on either side of the implant, were performed, rising in the direction of the incisal edge under the soft tissues that remained attached. One horizontal osteotomy was added apically connecting the two vertical osteotomies. A trans-palatal device was placed for anchorage to control the anterior teeth position. Immediately after surgery, continuous orthodontic traction was placed using an elastic chain connecting the trans-palatal device and the implant, plus an inter-maxillary elastic from the bonded bracket on the implant crown and the lower archwire hooks. To facilitate implant movement during traction, the trans-palatal arch was modified. After 3 months of traction, the implant with the temporary crown was in a good position, and the remaining space was closed. Stabilization was done with a final .021x.025 SSW for a period of 3 months. A new screwed zirconium rehabilitation was made and, after orthodontic device removal, a retainer was bonded, including the final prosthetic restoration. (Fig. 11).
A 64-year-old woman was referred to correct the prosthodontic restoration on the right maxillary first incisor with infraocclusion. This patient had been treated by implant therapy 20 years before. She was in good general health and did not present any contraindication to surgery procedure, but she had a high tobacco consumption, which she had decided to reduce. Clinical examination showed chronic periodontitis, the replacement of the right maxillary first incisor by an implant with infraocclusion, and a crown with a slight palatal position (Fig. 12). Soft and hard tissues around the implant and osseointegration were stable. The facial skeletal pattern was normodivergent. The actual implant position was due to 20 years of continuous alveolar growth. Considering the good palatal implant positioning at the time of the surgery, 20 years before, the right axis was kept, without any buccal side effect movement. A new screwed restoration would have been possible, but the prosthetic rehabilitation to compensate for the infraocclusion would have led to a disappointing result, with too long a crown and an incorrect gingival line alignment. For this reason, periodontal treatment was planned first before orthodontic preparation and implant relocation at the right level using the OBS technique.
Orthodontic preparation consisted of teeth alignment excluding implant and a .021x.025 SSW was placed on the maxillary and mandibular arches before surgery. When the alignment phase was completed, infraocclusion on the incisor prosthodontic crown was severely worsened, compared to the incisal edge of the adjacent teeth (Fig. 13A). Immediately before surgery, an overlay .016 Nickel-Titanium archwire was placed on maxillary teeth, including the implant. (Fig. 13).
The OBS procedure was performed on the buccal side with preservation of the implant soft tissue attachment. Immediately after surgery, orthodontic forces were applied. Every 2 weeks (Fig. 14), the patient was followed by the orthodontist for traction reactivation. After 2 months of orthodontic traction, the movement was stopped. New surgery was planned on the palatal side. Immediately after surgery, orthodontic traction was applied along the desired axis. Bone stretching movement allowed implant extrusion. After stabilization, a new crown was made and a retainer was bonded (Fig. 15).
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