From practitioner to practitioner - ZZI 01/2017

Dental implant rehabilitation of a patient with Down syndrome – interdisciplinary workflow

On the grounds of agenesis the following teeth were missing at the point of this initial prosthetic consultation: 18, 28, 35, 43. Additional missing teeth 14, 16, 38, 45, 48 (Fig. 1–3). Radiological imaging (orthopantomogram, OPG, Fig. 4) revealed teeth in regio 13, 23 and an apical lesion at tooth 46 due to insufficient tooth root treatment. The clinical and instrumental function analysis reflected a craniomandibular dysfunction as well as an overbite of 2 mm (enlarged sagittal plane) and an overjet of 2 mm on the right. The anterior tooth region of the mandibula reflects a marginal mobility (Miller Class I). Shortened tooth roots are characteristic and represent a frequent symptom of the underlying disease.

Therapy

In order to achieve a stable occlusal situation prosthetic-restorative treatment is indicated. Possible abutment teeth are prognostically vacant for non implant-retained prosthetic treatments. Partly prosthetic treatment with a removable prosthetic restoration is intolerable for the patient due to macroglossia and passive tongue pressure. This complies with Scully and Cawson who describe removable prosthetic restorations as problematic [18].

A functional masticatory rehabilitation is guaranteed by implant-supported rehabilitation with single-tooth crowns. In order to ensure sufficient primary and secondary stability 4 implants were planned in the maxilla taking the existing bone situation into account (regio 16, 14, 13, 23) and 2 implants in the mandibula (regio 35, 45), each of which were to be provided with implant-supported single crowns. Therapy planning comprised the integration of remaining teeth into the prosthetic concept by prosthetic-restorative treatment with individual crowns in 11, 12, 15, 21, 22, 24, 25, 26 and an endocrown in regio 46 as well as an onlay in regio 36.

For Down syndrome patients deficient cooperation in treatment, fear, lacking acceptance of the dentist and restricted tooth and oral hygiene are characteristic. The treatment concept therefore initially focused on implementing confidence-building measures and familiarising the patient with dental procedures before implementing digital implant planning.

The patient’s relatives were involved in each individual treatment step to enhance the patient’s confidence in the team. Microbial dental plaque was regularly removed to improve oral hygiene and to familiarise the patient with the dental instruments. Routine recalls at close intervals led to a higher acceptance of dental treatments on the part of the patient.

After having ensured a sufficient willingness to cooperate on the part of the patient due to the confidence-building measures, the revision of tooth 46 with following endodontic therapy was performed as a preimplantological treatment. This complication-free intervention exhibits that the patient had the necessary tolerance for the upcoming surgical intervention, even without general anaesthesia or sedation.

Surgical and prosthetic therapy

In order to align the implant positions to ensure an optimum final prosthetic treatment, backward planning is performed. 3D planning and operative implementation as well as later treatment require teamwork between the surgeon, prosthetic specialist and dental engineer. For the purpose of 3D planning digital volume tomographs (DVT, Planmeca ProMax) were performed using the NobelClinician Planning Software (Version: NobelClinician 2.3, Nobel Biocare Services AG, Zurich, Switzerland) for the maxilla and mandibula (Fig. 5).

Due to the insufficient aesthetic and functional situation a wax-up was necessary. This was produced in the laboratory. By means of optical scan a situation model was generated in the lab and read into the planning data set for 3D planning. In consideration of key anatomical structures the implant positions and angulations were planned (NobelClinician, Nobel Biocare). The implant lengths and diameters as well as angulations were determined and the implants (GC Aadva) ideally positioned in 3D planning (regio 13: ø 5.0 mm/length 12 mm; regio 14: ø 4.0/14; regio 16: ø 4.0/12; regio 23: ø 3.3/12; regio 35: ø 5.0/12; regio 45: ø 5.0/12). As sufficient bone material was available in the complete maxilla and mandibula, no augmentative measures were required.

After completing 3D planning a tooth-supporting pilot drill guide (NobelClinician, Nobel Biocare) for a 2-mm pilot drill was produced and used for dental surgery. The pilot drill guide was positioned on the remaining teeth, the correct position controlled and the 2-mm pilot drill performed (Fig. 6, 7). Due to the high level of cooperation on the part of the patient, it was possible to perform the intervention with local anaesthesia. The implants were inserted with primary stability and with sufficiently high torque (> 35 Ncm) in compliance with 3D planning. The initial primary stability is supported by an individually adapted drill protocol taking the various bone qualities into account in the case of the implant system used (GC Aadva).

The control X-ray exhibits regular inserted implants (Fig. 8) with regard to position and angulation. The patient received antibiotic and antiphlogistic medication prior to and after surgery. Seven days after surgery the stitches were removed. In the standard healing phase of 3 months routine hygiene consultations took place. During this phase the remaining teeth in region 11, 12, 21, 22 were used for temporary treatment in order to determine the patient’s tolerance with regard to function and aesthetics (manufactured: BSI Zahntechnisches Laboratorium, Guntramsdorf, Austria). The temporary dentures in the front teeth area, maxilla, were used to evaluate the patient’s requirements and expectations and serve as functional and aesthetical prototype. After the healing phase the implants were exposed without any complication within the scope of outpatient treatment.

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