The male patient in this study was 26 years old at the first presentation and showed definite symptoms of CCD. The patient was aware of his diagnosis, as he had been diagnosed by a pediatrician during childhood. Moreover, family history indicated that his father also had CCD. The primary reason for his visit was severe pain originating in the carious upper right first molar. After the initial pain treatment, the possibilities of creating a normal masticatory function and a natural-looking esthetic appearance were discussed. The unesthetic positioning of the patient’s teeth caused him tremendous amount of psychological strain, and consequently he avoided smiling. The patient’s general medical history showed no abnormalities, and there were no diseases that would contraindicate comprehensive dental rehabilitation. An initial alternative therapy, such as orthodontic treatment, had not been performed.
After controlling the pain and thorough cleaning of the teeth, a definitive assessment was performed (Fig. 1). Teeth 1, 5, 16, 19, 20, and 21 were missing. Teeth 6, 8B, 9A, 9B, 11, 15, 18, 19, 22–28, 31, and 32 were retained and displaced. Teeth 3, 7, and 19 were decayed. Therefore, the right maxillary molar  also had to be removed prior to any additional treatment. The primary teeth present were C and M–Q. Other findings included enamel hypoplasia, abnormal size and structure of the erupted teeth, a high palate with a deep furrow in the midline and a protrusive biting position. The periodontal examination did not reveal any abnormalities. There was significant dysfunction due to an open bite; only antagonist pair 2/31 showed static and dynamic occlusal contacts. The radiographs on admission (Fig. 2a–c) showed the typical signs of CCD—parallel wall alignment of the two sides of the mandible and narrow, pointed coronoid processes. In addition, the maxillary sinus on each side was hardly pneumatized, and a cyst lesion with a diameter of 18 mm was detected radiographically between teeth 8 and 10. The numerous non-erupted teeth (Fig. 3) and cysts in relation to the maxillary and mandibular anterior teeth made extensive surgical pretreatment necessary.
The treatment alternatives were explained to the patient in detail. Three possibilities were presented to him: (a) removal of all teeth and insertion of removable complete dentures; (b) preservation of a few strategic abutment teeth and insertion of dentures with double crowns as anchoring elements. In this plan, implants for strategic pillar multiplication were also suggested. (c) An implant-supported prosthetic restoration, either fixed or removable, after extraction of all teeth. The patient wanted a fixed, implant-supported restoration. This decision was influenced by his father’s treatment 5 years earlier, in which an implant-supported restoration was inserted. From a prosthetic and periodontal viewpoint, preservation of teeth 4, 12, 13, and 14 would have been possible. If the bite had to be changed, a crown restoration would have been necessary. The patient refused to receive any teeth because they “do not belong to him”.
The patient requested the removal of all his teeth and a long-term provisional restoration with complete denture prostheses. The surgical procedure was performed 1 year after the initial presentation. The extraction of the teeth, removal of the cysts, and osteotomy of the maxilla and mandible were performed under local anesthesia. The bone defects were completely covered after thorough curettage and complete removal of the cystic tissue. Teeth 17 and 18 were retained at this time, in accordance with the patient’s request. After removal of the required teeth, the pronounced defect situation became apparent. However, the defects were not filled with autologous bone or bone-substitute materials. Removable complete dentures were inserted as temporary restorations. These temporary prostheses were also necessary to study the patient’s occlusion. Since there was no indication of the position of the occlusal plane, the lengths and widths of the prosthetic teeth were taken from the cone-beam computed topography (CBCT) by measuring the sizes of the permanent teeth.
The function was checked and corrected several times during the healing period.
The new occlusion established in this way served as a template for the fabrication of the drilling template and for transferring the jaw relation during the fabrication of implant-supported long-term temporary restorations.
During the healing period of 6 months, the alveolar ridges atrophied considerably. Likewise, CCD-typical micrognathia and pseudoprognathia were seen in the edentulous state. A new CBCT scan was performed for design purposes. Casts of the jaws were mounted on an articulator in relation to the cranial base. Digital teeth set-ups were superimposed with the CBCT in an implant planning software (coDiagnostiX, Dental Wings, Inc., Montreal, Canada). A prosthetically oriented three-dimensional design of the implant positions was created, and a drilling template was constructed.
We planned to insert six implants each in the maxilla and mandible. The implant positions were determined by template-guided pilot drilling. A transgingival pilot hole was drilled and used to determine the exit point and axial direction of the implant. The prosthetic plan involved using screw-retained fixed dental prostheses (FDPs) in the maxilla and mandible. A complete preparation of the implant beds using the template was not planned because of the restricted mouth opening. After the pilot drilling, the jawbone was exposed, and complete freehand preparation was performed. Because of the low radiological density of the bone structure, implants with an expected high primary stability (BLX implant, Straumann AG, Basel, Switzerland) were inserted. All implants had a diameter of 4.5 mm. The lengths were 8–14 mm, depending on the available bone.
All implants could be inserted in a primarily stable manner (insertion torque > 35 Ncm). Because of the adequate bone quantity and computer-supported implant position planning, no augmentation measures had to be implemented (Fig. 4a–d). Thus, the planned temporary restoration could be performed immediately after implant placement. For this purpose, abutments for screw-retained FDPs were attached to the implants. Owing to the design and template-guided insertion, only straight abutments could be fitted. Impressions of the implants were taken after suturing. After the facebow transfer and bite registration, the implants remained unsupported for 10 h. During this time, long-term provisional fixed dental prostheses were fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM).
The plaster models were digitized (3Shape Scanner D 700 3Shape A/S, Copenhagen, Denmark). The occlusion was adjusted with a postoperative silicone bite. In addition, it was checked and corrected using the previous full dentures. Since implantation was carried out in a minimally invasive manner, these could be repositioned relatively precisely on the plaster models. The long-term temporary implant-supported dentures were then designed using the corresponding CAD software. The FDPs were milled from multicolor polymethylene methacrylate (PMMA) plastic. The basal part was then covered with a gum-colored plastic. After bonding the titanium adhesive bases, the static and dynamic occlusion of the dentures was corrected on the articulator. This procedure requires close coordination between the dental team and the dental laboratory. The procedure and processes must be coordinated very well in order to ensure fast production.
The two FDPs were inserted the following day (Fig. 5a–d). The patient was kept on soft food for 6 weeks. An analgesic (ibuprofen 500 mg) was prescribed, and the patient was instructed to take it at his own discretion within the prescribed maximum dose.
After the implants healed for 4 months, the final prosthetic restoration was performed. The healing period passed without any special incidents. However, functional adaptation of the denture was observed during this phase. There was no discomfort related to either the implants or the prosthetic restoration. After removing the temporary restoration, we checked whether the final abutments were tightened to a torque of 35 Ncm. An open-tray impression of the implants was taken. Bite registration was performed using the long-term temporaries after fabricating the cast. This allowed the tested position to be safely transferred to a fully adjustable articulator.
Trial fitting of the framework was performed using a wax setup positioning of the teeth. As no concerns arose regarding static and dynamic occlusions, esthetics, or phonetics during this check, the anatomically contoured metal alloy frameworks were veneered using acrylic resin (PhysioStar NFC, Candulor, Roelasingen-Worblingen, Germany). The FDPs were fitted in the following session (Fig. 6a–f). The screw channels were closed with Teflon tape and a light-curing composite material. By raising the vertical dimension between the opposing arches, a satisfactory profile was created. In addition, a prosthesis-based adjustment for the micrognathia of the maxilla and pseudoprognathia was achieved with the denture. At the conclusion of the procedure, the patient reported feeling very satisfied with the functional and esthetic outcome of his denture (Fig. 7). To date, the patient has been followed for 9 months, and no complications have been reported.