The introduction of oxide ceramics in dentistry provided new treatment options for patients and clinicians. To date, zirconia has shown superior biomechanical properties compared to other oxide ceramics. Since it was introduced in dentistry, zirconia has been used as a framework material for all ceramic crowns and fixed dental prostheses (FDP), as well as for implant abutments. Because of its material properties and tooth-like color, zirconia is also the material of choice for dental implants nowadays. Moreover, human studies have demonstrated a reduced bacterial adhesion on zirconia compared to titanium, as well as fewer inflammatory cells in the peri-implant soft tissue of zirconia compared to titanium. These findings suggest that less periimplantitis may occur around zirconia implants compared to titanium implants. In a recent systematic review (Hashim et al 2016), the overall survival rate of one- and two-piece zirconia implants after 1 year of function was 92% (95% CI 87-95). According to this review, it seems that zirconia implants could serve as a metal-free alternative to titanium implants. On the other hand, it has to be pointed out that there is still a lack of data regarding the long-term performance of zirconia implants. Further clinical studies are needed in order to obtain more data on the long-term outcome of zirconia implants. In this context, case reports are also valuable for identifying the risk factors for technical and biological complications.
Initial situation
A 69-year old patient attended her scheduled maintenance appointment at the University Clinics of Dental Medicine in Geneva (Division of Fixed Prosthodontics and Biomaterials) in February 2014. The patient was healthy and a non-smoker. During the routine examination she complained of a slightly painful sensation at tooth 35. The tooth had been endodontically treated and restored with a crown two years ago. The clinical evaluation confirmed the slight pain on percussion of tooth 35. Furthermore, the tooth showed increased mobility of grade 2 and a localized probing pocket depth of 7mm. A periapical radiograph to complete the examination showed a radiolucency mesial to the root (Fig. 1). A presumptive diagnosis of vertical root fracture was made.
Treatment planning
An exploratory surgery was planned in the Division of Periodontology (University of Geneva). If the presumptive diagnosis was confirmed, the plan was to extract tooth 35 and perform a ridge preservation procedure. After the bone healing period, late implant placement of a Straumann® PURE Ceramic Implant 4.1 diameter on position of 35 was planned. After successful osseointegration, the implant was to be restored with a hybrid ceramic (VITA Enamic®, VITA Zahnfabrik, Bad Säckingen, Germany) crown using an intra-oral optical impression and CAD/CAM technology to follow a digital workflow.