Please activate JavaScript!
Please install Adobe Flash Player, click here for download

Dental Tribune United Kingdom Edition

May 201418 Implant Tribune United Kingdom Edition page 17DTß mas, etc.) resulted in the patient being entirely opposed to an- other intervention of this kind on the opposite side of the mouth. During an appointment in October 2011, I was able to per- suade the patient to accept im- plant treatment. I suggested first removing the three-unit bridge on teeth 23–25 and then extract- ing the roots of teeth 23 and 25, as well as seating of a denture on the day of the extraction, fol- lowed by placement of three im- plants in regions 23–25, the ex- traction of tooth 26, and seating of a four-unit bridge as the final prosthetic solution. As the height of the avail- able bone around tooth 26 was insufficient, I would not place an implant in that area but a tooth extension (a sinus lift would oth- erwise have been essential). The treatment plan was accepted by the patient two weeks later, and teeth 23 and 25 were extracted at the end of the month. The patient was seen on 10 January 2012 for implant placement: two implants (No- belReplace RP, Nobel Biocare) with a diameter of 4.3mm and a length of 13mm for regions 23 and 24, and one implant (Nobel- Replace WP) with a diameter of 5mm and a length of 10mm for region 25. Tooth 26 was ex- tracted on the same day without placement of an implant as al- ready mentioned. In May 2012, implant-level impressions were taken (open- tray impression technique), and the patient’s occlusion was re- corded using silicone and a bite tray. Owing to the constraints related to the angulation of the implants in regions 24 and 25, I opted for titanium abutments. The angle of the implant in re- gion 23 allowed for the insertion of a titanium–zirconia abutment for good gingival grip and a bet- ter aesthetic result. Ten days later, two titanium abutments (ANA. T, Laboratoire Dentaire Crown Ceram) and one titanium–zirconia abutment (ANA. TZ, Laboratoire Dentaire Crown Ceram) were screwed onto the implants at a torque of 35N, and sealed with compos- ite. An adjustment check of the contact points and of the occlu- sion was performed, followed by cementation of a ceramic bridge with a zirconia framework. A follow-up visit took place three days later. Technique For this case, it was possible to use abutments made from dif- ferent materials according to the angulation of the implant: titanium for the pronounced angulations, and a combination of titanium and zirconia for the angulation with no particular constraints. It would have been equally possible to use a tita- nium abutment for the implant in region 23 but I opted for the titanium– zirconia abutment to obtain a better aesthetic result in the anterior region: bright- ness, translucency and no visible metal margin. Customised CAD/CAM pros- thetic elements and abutments respect the dental anatomy and allow extremely precise seating of a bridge on implants. Perio- dontal maintenance is therefore easier owing to easy access with a toothbrush because of the pre- determined interdental spaces. The simplicity of the process saves a considerable amount of time: no adjustments are neces- sary, the bridge is seated imme- diately, the occlusion is usually ideal, and greater accuracy can be achieved. In addition, only two appointments are necessary: one for impression taking and another for seating of the bridge. Dental technician’s perspec- tive When the laboratory (Labora- toire Dentaire Crown Ceram) re- ceived this case, we were asked to create three customised ana- tomical abutments with a tita- nium interface for an individual and more precise fit, respecting the requirements of biocompat- ibility and biomechanics, and a coronary part in zirconia for a better aesthetic result. Once the moulds had been cast, we determined that the considerable angulation of the implants in regions 24 and 25 and their shallow position in the tissue posed difficulties regard- ing the design of titanium–zir- conia abutments. However, Dr Lachkar explained to us that in this case (ie the patient’s reluc- tance to undergo pre-implant surgery) he was forced to place the implants in the bone avail- able and not necessarily in the ideal situation according to a prosthetic plan. In this case, the titanium in- terface would have considerably exceeded the buccal surface and it would therefore have been necessary to reduce it. The bond- ing surface would therefore have been limited, which would have resulted in a great loss of me- chanical resistance. We thus de- cided to use a titanium abutment manufactured from a single block and specially made to allow for such substantial angulations for teeth 24 and 25. For tooth 23, the implant angle allowed for a titanium–zirconia abutment, which was preferred to a tita- nium abutment for a better aes- thetic result. DT About the author Dr Thierry Lach- kar is a dental surgeon (Paris Di- derot University) and has been a practitioner for 15 years. He is a gen- eral practitioner and he works at a dental surgery in Paris. He has specialist postgraduate training in conservative dentistry and in endodontics. He can be contacted at drlachkar@yahoo.fr. ‘Customised CAD/ CAM prosthetic elements and abut- ments respect the dental anatomy and allow extreme- ly precise seating of a bridge on im- plants’