Dental Tribune Middle East & Africa Edition | 2/2019 ◊Page D2 IMPLANT TRIBUNE D3 Fig. 13: Mandibular arch anaesthetised. Fig. 14: Mandibular surgical guide stabilised. Fig. 15: Implants and healing caps with surrounding grafting. Fig. 16: Im- mediate dentures with soft relining. Fig. 17: Maxillary ridge four months post-op. Fig. 18: Mandibular ridge four months post-op. radiographic evaluation indicated sufficient bone volume for full-arch implant therapy. Treatment options were presented to the patient for her edentulous upper arch and non-restorable man- dibular dentition, including vari- ous combinations of fixed and re- movable implant prostheses. This involved a discussion of complete edentulism and its problems, con- sequences and solutions, the effect of tooth loss on oral health, and the differences in stability and function afforded by each treatment option. Dental financing programmes were explained, which is an important part of treatment presentation, as it can help make implant therapy fea- sible for patients who cannot cover the entire cost upfront. The patient strongly desired fixed restorations, as she had grown quite frustrated with her removable max- illary denture over the years. In addi- tion, the patient had a pronounced gag reflex, making the fixed option optimal because it would free up the palate. An FP 3 prosthesis was required for the patient’s maxillary arch, which had undergone substan- tial bone resorption and gingival re- cession. The tissue contours would also need to be recreated in the man- dible, where bone levelling was re- quired to remove undercuts, create an ideal occlusal table, properly seat a bone-supported surgical guide 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 labiolingual bone volume re- quired that several of the implants be tilted in a manner that would have required access holes too far to the facial aspect if screw-retained prostheses were to be prescribed. This would have been especially problematic for this patient, as ciga- rette smoking tends to darken the composite used to seal the screw ac- cess holes. The patient also desired prostheses that occupied as little faciopalatal space as possible, further indicating a cementable solution. Thus, custom abutments would be utilised to correct the angulation of the implants and support full-arch BruxZir restorations. The monolithic construction of the FP3 prosthesis, in which both the gingival areas and teeth are milled from the same block of solid zirconia, would ensure the longest-lasting restoration possible. The patient returned for the records appointment, where maxillary and mandibular impressions were taken so that immediate temporary dentures could be fabricated for de- livery at the surgical appointment. CBCT scanning was performed using a CS 8100 3D scanner (Carestream Dental) to provide the information needed for virtual treatment plan- ning. The 3-D data obtained from the CBCT scans was used to determine the ideal length, width and place- ment of the implants in the key po- sitions of the patient’s edentulous arches, including the first molar, first premolar, canine and central incisor regions (Figs. 3–6). From the digital treatment plan cre- ated by 3D Di- agnostix, bone-level surgical guides were produced for the maxilla and mandible (Figs. 7 & 8). The Hahn Tapered Implant (The Hahn Tapered Implant System) was selected for the procedure because the pronounced thread design would help achieve optimal posi- tioning and primary stability. The ta- pered shape and wide range of sizes also simplified the task of situating the implants in the key positions around the arch. Its conical inter- nal 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, intra- venous sedation was administered to the patient. The bone-level sur- gical guide was seated over the pa- tient’s maxilla once the tis- sue had been reflected, and the fixation pins were tightened (Fig. 9). The implant osteotomies were created following the simplified surgical protocol of the Hahn Tapered Implant System. Eight implants were placed from second molar to second molar in the maxillary arch (Figs. 10&11). Healing abutments were connected to the implants to help prepare the soft tis- sue for the restorative phase (Fig. 12). Next, the patient’s untreatable man- dibular teeth (Fig. 13) were extracted using the Physics Forceps (Gold- enDent), a flap was reflected, and an alveoloplasty was performed. A bone-supported guide was seated in order to control the location and Fig. 19: Inclusive CAD/CAM abutments. Fig. 20: PMMA Smile Composer. Fig. 21: Post-op retracted open-bite view. Fig. 22: Post-op retracted closed- bite view. angulation of the implant osteoto- mies (Fig. 14). As the Hahn Tapered Implants were threaded into place, their deep, sharp threads engaged the walls of the socket sites and helped maintain proper position toward the lingual aspect. Because of anticipated tissue swelling as a result of the bone levelling proce- dure, 5mm high healing abutments were connected to the implants in the lower arch (Fig. 15). The immedi- ate dentures were soft-relined with Mucopren (Kettenbach) to seat over the Hahn Tapered Implant Healing Abutments, the hourglass shape and undercuts of which provided a degree of retention that enhanced dental function for the patient dur- ing healing (Fig. 16). Four months later (Figs. 17 & 18), the healing abutments in the maxillary arch were surgically exposed and the tissue appropriately approximated and allowed to heal. Approximately two to three weeks later, Hahn Ta- pered Implant Impression Copings were seated and closed-tray impres- sions taken with a polyvinylsiloxane material (Panasil, Kettenbach), as was a bite registration (Futar, Ketten- bach). Because the immediate den- tures were well fitting and satisfac- tory to the patient, duplicates were provided to the laboratory to aid the restoration design process. Based on the impressions, the labo- ratory poured and scanned stone models, creating a digital representa- tion of the patient’s arches on which the designs for custom abutments and the cementable restoration were created. Inclusive Titanium Custom Abutments were fabricated with cor- responding PMMA Smile Compos- ers. The patient returned for clinical eval- uation of the prosthetic design. The custom abutments were delivered us- ing laboratory-provided acrylic delivery jigs, which helped ensure proper orientation during seating (Fig. 19). Owing to the precision of the digital design process, the fit of the custom abutments was ideal, es- tablishing margins that were at or a slight distance from the gingival sur- face. This simplified the removal of excess cement from the margins and illustrates the advantages of CAD/ CAM–produced abutments. The PMMA Smile Composers were seated over the custom abutments, and slight alterations were made to fine-tune the gingival margins, length of teeth, and bite (Fig. 20). A bite registration was taken with the try-in bridges in place. The PMMA Smile Composers were returned to the laboratory along with photographs, the bite regis- tration and instructions for minor modifications, including lowering the gingival margins of the man- dibular prosthesis and raising the gingival margins of the maxillary prosthesis. The laboratory scanned the adjusted PMMA try-in bridges, made the requested alterations to the prosthetic designs, and milled the final prostheses from BruxZir Solid Zirconia. The final restoration was delivered at the next appointment and estab- lished accurate fit, function and in- terocclusal relationship (Figs. 21&22). No adjustments were needed for the monolithic zirconia prostheses be- cause of the PMMA try-in process, which captured the precise modi- fications needed for proper form and aesthetics. Final radiography confirmed complete seating of the BruxZir restoration on the Inclusive Custom Implant Abutments. The pa- tient was extremely happy with the reconstruction of her maxillary and mandibular arches, which restored aesthetics, dental function, comfort and confidence. Conclusion The accuracy of dental CAD/CAM technology and the versatility of prosthetic materials allow practi- tioners considerable flexibility in restoring the edentulous arch. For clinicians who prefer a cementa- ble solution or cases in which bone anatomy precludes a screw-retained prosthesis, the monolithic zirconia restoration over custom abutments excels in restoring the teeth, as well as the hard and soft tissue of the fully edentulous patient. Editorial note: A list of references can be obtained from the publisher. This article was originally published in CAD/CAM international magazine for digital dentistry, Issue 1/2018. Dr Ara Nazarian maintains a private practice in Troy in Michigan in the US with an emphasis on comprehensive and restorative care. He is a diplomate of the International Congress of Oral Implantologists and the founder and Chief Clinical Officer of the Ascend Dental Academy. He has conducted lectures and hands-on work- shops on aesthetic materials, grafting and dental implants throughout the US, Europe, New Zealand and Australia.