The restoration with zirconia implants is discussed due to improved material properties such as low plaque affinity and good biocompatibility as an alternative to titanium implants. This case report describes an esthetically appealing restoration in the premolar region of a young man. Despite slight bone and soft tissue resorption, implantation without complicated bone augmentation was possible. In patients with thin mucosa biotype in particular, the use of zirconia implants should be considered due to the tooth-colored esthetic.
PRODUCT INFORMATION BY THE MANUFACTURER
The Straumann® PURE Ceramic Implant is the result of more than 9 years of research and development. It has a natural looking ivory color, a feature that makes the implant look more like a natural tooth and supports the clinician in cases of thin gingiva biotype or soft tissue recession. It has a monotype design based on features of the Straumann® Soft Tissue Level Standard Plus and Straumann® Bone Level Implants. According to a survey (data on file at Straumann), patients would prefer tooth-colored implants, if given the choice between ceramic and metal implants. With the Straumann® PURE Ceramic Implant, clinicians can offer their patients a natural and highly esthetic solution, benefitting from favorable soft tissue attachment around zirconia implants.
INITIAL SITUATION/CLINICAL FINDINGS
Initial situation. An 18-year-old patient was seen at our joint practice following completion of orthodontic treatment. For reasons of symmetry, the space was closed at premolar width with agenesis in regions 15, 14, 24, 25, 35 and 45. In region 46, tooth 46 was extracted at the age 15 years due to a deep cavity and the space closed orthodontically to premolar width. In the third quadrant, the interdental space in region 35 was closed due to mesialization of tooth 36. Following completion of orthodontic treatment with interdental spaces in regions 14, 24 and 44 and a desire for implantological treatment, the patient was seen at our practice (Fig. 1). The patient rejected alternative prosthetic treatment options including fixed one- or two-arm ceramic bridges. The patient had no relevant systemic diseases.
Clinical findings. The oral hygiene of the patient at the time of initial presentation could be improved. Clinically, there was bone and soft tissue resorption in regions 14, 24 and 44 in both the vertical and horizontal dimension as observed in the agenesis with no prior orthodontic space closure. In regions 14 and 24, there was sufficient vertical bone due to anatomically distal displacement of the recess of the maxillary sinus. In preoperative planning, a vertical bone height of 18.6 mm was measured in region 44 up to the inferior alveolar canal, which was more than sufficient (Fig. 2). Based on the present clinical conditions and the young age of the patient, we decided for placement of ceramic implants.
The surgery was performed under local anesthesia with vestibular infiltration anesthesia of articaine with epinephrine of 1:200,000 (Ultracain® D-S, Sanofi Aventis) in regions 14, 24 and 44, as well as conduction anesthesia of the N. palatinus major, bilateral and N. mentalis, right. The crestal bone was exposed using the raspatory by means of a slightly lingual or palatal incision and detachment of a mucoperiosteal flap (Fig. 3). The minimum distance of the implant shoulder to the adjacent tooth of 1.5 mm and guidelines for orofacial implant position were maintained. The bone was prepared following strict surgical implantation protocol. The alveolar ridge in an ideal position to obtain a flat surface was prepared in all regions using the round burr with a diameter of 2.3 mm at 800 rpm (Fig. 4). The implant bed (first, pilot drill Ø 2.2 mm at 800 rpm, then pilot drill Ø 2.8 mm at 600 rpm) was prepared in regions 14 and 24 to 12 mm and in regions 44 to 10 mm with adequate water cooling. Twist drills were then used to expand the implant bed at constant aspect ratios to 2.8 mm and 3.5 mm at 500 rpm (Fig. 5). The profile burr was used in regions 14 and 44 to reduce the cortical crestal pressure during implant placement (Fig. 6). With bone class 1 in regions 14 and 44, the standard tap was used at 15 rpm. In region 24, tap preparation was unnecessary with bone class 2 – 3. Following preparation of the implant bed, a Straumann® PURE Ceramic Implant (Monotype) Ø 4.1 mm with an abutment height (AH) of 5.5 mm and a length (L) of 12 mm was placed in region 14 at 15 rpm, a Straumann® PURE Ceramic Implant Ø 4.1 mm AH 4 mm L 12 mm was placed in region 24 and a Straumann® PURE Ceramic Implant Ø 4.1 mm AH 5.5 mm was placed in region 44 (Fig. 7). The coronal-apical implant positions were chosen, so that the margin of the ZLA® surface is epicrestal (Fig. 8). The implant abutments were then closed using back-and-forth sutures with Vicryl 4-0 and an OPTG was taken for postoperative radiographic follow-up (Fig. 9 and 10). A mouthguard was used to protect the implants (Fig. 11).
The patient was prescribed Cefuroxime antibiotic therapy 1-0-1 for five days postoperative. He was instructed in detail after surgery on postoperative oral hygiene measures. The sutures were removed on the seventh day postoperative. The patient was seen for a clinical follow-up three months after implantation. Clinically, there were irritation-free peri-implant gingival conditions in all regions with nearly excessive soft tissue growth (Fig. 12), which can be attributed to the good biocompatibility of zirconia. A situation impression is taken with alginate to fabricate a custom tray. A final impression was taken one week later using Impregum (Impregum™ Penta Soft, 3M ESPE) and the custom tray prepared previously. A master cast was initially fabricated in the laboratory. Long-term temporary restorations were then fabricated in acrylic to optimize the peri-implant soft tissue form. Prosthetic teeth (Pala Mondial, Heraeus Kulzer) with tooth-colored universal acrylic (Palavit 55 VS, Heraeus Kulzer) were fitted on the implant connections (Fig. 13). The esthetically appealing long-term temporary restorations were fixed using zinc-oxide eugenol cement (Temp Bond, Kerr Dental Products) (Fig. 14). The patient was seen at our practice regularly to achieve an optimal mucosal contour by applying or removing material. Once the ideal marginal gingival conditions were formed, the final restoration was carried out after six months. New impressions were taken (Impregum™ Penta Soft, 3M ESPE) to optimally replicate the peri-implant gingival situation. 0.6 mm copings were then fabricated in the laboratory using lithium disilicate glass ceramic (IPS e. max Press LT, Ivoclar Vivadent). The final crowns were modelled on the copings using highly esthetic layering ceramic (IPS e. max Ceram, Ivoclar Vivadent). On subsequent follow-up, mucosal conditions were irritation-free in all regions. Following removal of the long-term temporary restorations, cleaning the abutments and examination of the proximal and occlusal contacts, the ceramic crowns with glass ionomer cement were used (Ketac™ Cem, 3M ESPE) (Fig. 15 and 16).