19 November 2022

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Case report: clinical and radiographic performance of two-piece zirconia implants in the posterior mandible

Alexandre Marques

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Introduction

Over the last few years, the number of patients requiring metal-free rehabilitation solutions for implants and prostheses has increased. In parallel, there are reports in the literature of hypersensitivity to titanium implants.

Ceramic implants based on yttria-stabilized zirconia (Y-TZP) are an alternative material to titanium, with similar biological and mechanical behaviors. Initially, zirconia fixtures were one-piece components with reduced prosthetic versatility. To avoid these limitations, two-piece implants were designed.

The present case report describes a patient with two posterior mandibular failing teeth with extensive prosthetic treatments and substituted by two ceramic implants.

Clinical Case

A 58-year-old woman complained about pain in the region of teeth 35 and 36. On clinical examination, it was possible to observe a slight increase in volume around them and mobility. In the tomographic exam, it was possible to perceive that the teeth in question had bone loss and endodontic lesions.

The patient signed a consent form, and the surgery was performed under local anesthesia. The treatment options were presented to the patient, and she opted for the extraction of both teeth and immediate installation of ceramic zirconia implants. The treatment involved the extraction of tooth elements 35 and 36, with immediate installation of two-piece zirconia ceramic implants and the fabrication of two immediate provisional restorations.

The extractions were performed atraumatically using manual periotomes and forceps, preserving the buccal plate.

Two two-piece ceramic implants (Neodent Zi Ceramic Implant®– Curitiba – Brazil) were placed into fresh sockets 3.75mmx11,5mm (tooth 35) and 4.3mmx11,5 (tooth 36).

The installation of the implants was conducted according to manufacturer's recommendations and were placed at the crestal bone level. The insertion torque value achieved for both implants was 50 Ncm. This clinical primary stability allowed immediate loading.

Two stock zirconia abutments 4.5mmx5.0mmX2.5mm (CR Zi Pillar®) supported cemented provisional restorations made with light-curing composite resin. The fresh sockets were filled with bone substitute graft material (Straumann® maxresorb® 0.5-1.0mm – 0.5cc). A final x-ray was performed to check the positioning of the implants.

The three-month postoperative period was uneventful. Conventional impressions were taken with addition silicone with putty and regular body, using the closed tray technique. Two lithium disilicate crowns (Emax®) were manufactured and cemented onto the prosthetic abutments with adhesive cement (Dual RelyX™ U200 - 3M). Occlusal adjustments were performed.

Immediate post x-ray shows stability of the marginal bone level compared to the immediate post operative radiography. The patient has been followed up periodically for the last six months and there have been no complications to date.  

Conclusion

Full mouth rehabilitation with two-piece screw-retained ceramic implants is an option for patients. Two-piece ceramic implants are easier to transition into for a clinician familiar with conventional titanium and titanium alloyed implants. However, it should be noted that case selection and rigorous treatment planning are crucial for the success of such rehabilitations. Ceramic implants do not have the prosthetic flexibility and options their titanium counterpart has, therefore biomechanically and prosthetically driven treatment is important.

Learn more about Dr. Marques' research on ResearchGate. 

This case was developed by Alexandre Marques Paes da Silva, Daniel Telles and Eduardo José Veras Lourenço, faculty at the State University of Rio de Janeiro (UERJ-RJ).