CAD/CAM international magazine of digital dentistry No. 4, 2016

| case report full mouth restoration 18 CAD/CAM 4 2016 The patient strongly desired fixed restorations, as he had grown quite frustrated with his removable maxillary denture over the years. In addition, the patient had a pronounced gag reflex, making the fixed option optimal as it would free up the palate. An FP3 prosthesis was required for the patient’s upper restoration, which had undergone substan- tial bone resorption and gingival recession. The tissue contours would also need to be recreated in the mandible, where bone leveling was required to remove undercuts, create an ideal occlusal table, properlyseatabone-supportedsurgicalguide,and establish adequate bone width in which to place the implants. The anatomy of the patient’s ridges called for a cementable solution, as the labial-lingual bone vol- umerequiredthatseveraloftheimplantsbetiltedin amannerthatwouldhaverequiredaccessholestoo far to the facial if a screw-retained prosthesis were to be prescribed. This would have been especially problematic for this patient, as cigarette smoking tendstodarkenthecompositeusedtosealthescrew access holes. The patient also desired prostheses that occupied as little facial-palatal space as possi- ble, further indicating a cementable solution. Thus, custom abutments would be utilized to correct the angulationoftheimplantsandsup- port a full-arch BruxZir restoration. The monolithic construction of the FP3 prosthesis, in which both the gingival areas and teeth are milled from the same block of solid zir- conia, would ensure the longest- lasting restoration possible. The patient returned for the records appointment, and upper and lower impressions were made so immediate temporary dentures could be fabri- cated for delivery at the surgical appointment. CBCT scanning was performed to provide the in- formation needed for virtual treatment planning. The three-dimensional data obtained from the CBCTscanswasusedtodeterminetheideallength, width and placement of the implants in the key positions of the patient’s edentulous arches, in- cluding the first molar, first premolar, canine and central incisor regions.1 A total of eight implants would be placed in each arch, facilitating a pros- theticdesignthatminimizescantileversandpontic spans. From the digital treatment plan, a tissue-sup- ported surgical guide was produced for the maxilla while a bone-level guide was created for the mandible, where a flap was required in order to evaluate the extraction sites and perform the alveoplasty. The Hahn Tapered Implant was selected for the procedure because the pronounced thread design would help achieve optimal positioning and pri- mary stability. The tapered shape and wide range of sizes also simplified the task of situating the implants in the key positions around the arch. Its conical internal hex connection results in a very stable seal between the implant and prosthesis, which is beneficial for crestal bone preservation and soft-tissue health.3 At the surgical appointment, IV sedation was ad- ministered to the patient. The tissue-level surgical Figs. 10a & b: The Hahn Tapered Implants were threaded into their predetermined mandibular locations and allowed precise directional control in the extraction sockets. Fig. 11: After achieving final positioning of the mandibular implants with a torque wrench, 5-mm-tall healing abutments were placed. Fig. 12: Four months after surgery, a resonance frequency measurement of the osseointegrated implants was taken with an Osstell ISQ® stability meter (Osstell USA; Columbia, Md.), which showed stable implant support. Figs. 13a & b: Transfer copings were connected to the implants, and closed-tray final impressions were taken. Fig. 12 Fig. 13a Fig. 13b Fig. 10a Fig. 10b Fig. 11 42016

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