Cement-retained metal ceramic crowns designed for natural teeth or implants

>> A case presentation <<

 

Our male patient (BS, born 1963) reported at our clinic with the following requests:

  1. He is looking to have his missing teeth replaced and his mastication restored.
  2. For BS, masticatory function enjoys priority over aesthetics
  3. He desires to have his old metal ceramic bridges replaced and be able to smile without embarrassment again
  4. He desires to regain his self-esteem both amidst his family and at his workplace
  5. He is looking for a permanent solution as far as possible

 

Prior to treatment: initial state of the mouth and the first panoramic radiograph


Post treatment: lower upper metal ceramic circular bridge retained on implants and teeth

 


The panoramic radiograph displays an implant-retained metal ceramic circular bridge. The upper rear implants could only be installed following a sinus lift (bone graft).

 

The preparation of implant-retained permanent tooth replacements usually breaks down to 3 phases:

  1. Tooth extraction
  2. Implantation following 3 months’ healing period
  3. Preparation of crowns and bridges following another 3 months’ time

As can be seen, the process generally spans half a year, but with BS the replacement procedure dragged on for a particularly long time what with the extent of bone loss and the weak structure of remaining bone.

 

First treatment, 3 workdays

 Having proved beyond repair, unfortunately, several teeth had to be extracted in the first sitting. Teeth beneath the old bridge had decayed and the inappropriately root canal treated teeth were infected (dental foci). All upper teeth and the lower molars were removed in the first sitting. A provisional denture was immediately prepared at the chairside in order to provide teeth over the 3 month recovery period ensuring that the patient can smile and eat, and keeping up the patient’s self-esteem and quality of life.


Panoramic radiograph of the initial condition

 

Following tooth extractions, the patient leaves the clinic with a provisional upper denture

 

 

Second treatment following 3 months’ healing period, 3 workdays

Following 3 months’ healing time, a CBCT (Cone beam computed tomography) scan was made in order to ensure a 3 dimensional examination of the bone mass prior to implantation. Based on the CT scan it was established that the bone height was bilaterally inadequate in the area of the upper molars warranting a so-called sinus lift, a kind of bone graft. In the mandible there was sufficient bone mass in the area of missing molars for implants to be installed, a bone graft was therefore performed in the upper arch and implants were placed in the lower arch (2 each side)

The provisional denture prepared following tooth extraction is relined to suit the altered anatomical relationships and ensure a comfortable fit.

It is important to minimise the wearing time of the provisional removable dentures following bone graft and/or the installation of implants. You are advised to wear the removable denture only at your workplace or places where you are required to talk or smile. When at home, remove the denture as soon as possible! Be sure to keep the mouth and denture clean and see that the bone-grafted/implanted area is not exposed to undue pressure, and the removable denture does not ”waggle” on the implants. Pressure exercised by the denture reduces blood circulation, hinders healing, causes cracking and infection and, worst of all, may result in the expulsion of the implant, however successful the implantation might have been. This is supremely important for healing to be successful!

 

A CT scan showing the maxilla, facial sinuses where bone height and width can be examined in 3 dimensions. The lower 3 pictures evidence a residual bone height of a mere 6.46 mm, indicating a bone graft surgery (sinus lift).

 

A CT scan of the mandible and the planning of implants. The CT scan clearly shows a bone height of 10.2 mm and bone width of 11.8 mm, which is perfectly suited for the placement of an implant shorter in length but wider in girth.

Follow-up panoramic radiograph on completion of the sinus lift in the upper arch and the placement of the lower 4 implants.

 

 

Third treatment due after 6 months’ healing, 3 workdays

Following 6 months’ healing (a bone graft always requires 6 months’ healing time) the upper (8) implants were installed. Since the implants proved very stable Dr Csongor Suba decided to seal the exposed gum straight with gingiva formers. If the stability of an implant measures less than 30 Ncm, one more surgical intervention is required with which to expose the implants individually and seal them with gingiva formers which, by protruding from the gum, see that the gum is shaped appropriately and ensure an ideal gum contour for the permanent abutment.

Follow-up panoramic radiograph following the placement of the 8 implants in the maxilla with the gingiva formers

 

 

Fourth treatment following 6 months’ healing, 10 workdays

Following another 6 months the permanent tooth replacement was ready to be installed. Cement-retained metal ceramic bridges were prepared for teeth and implants. Fortunately both BS’ financial means and the bone mass made it possible to prepare a permanent cemented tooth replacement.

This is the longest of all treatments. Precision impressions are taken of the implants by means of special closed-spoon impression copings. Natural teeth are prepared (filed) and their impression is taken so as to allow for the placement of crowns. On completion of the impressions several trial fittings need to be performed as the dental technician proceeds with the fabrication of the crowns. The framework (substructure) is test fitted (tried in) to check whether the impressions were accurate, the denture framework is true, and all tooth replacements are in perfect alignment with the master cast. This is when the bite, the length of the framework and teeth are checked and the middle position of the two central incisors and the teeth’s appropriate backward course are verified. At the preliminary trial insertion of the denture the crowns are almost ready, the ceramic is already sintered onto the metal framework and the patient’s bite (masticatory function), and the shape of the crowns, the middle line and smile line (aesthetics) can be checked with better accuracy. Several days elapse between the different trial fittings, during which the dental technicians are working at full tilt at the laboratory.

Patient BS was supremely satisfied on completion of the treatment, and is now able to smile and chew again, and has recovered his self-esteem.

 

The fabrication phases of implant-retained metal ceramic crowns, bridges in photographs:

 

The metal framework (substructure) of the metal ceramic circular bridge to be retained by the upper implants

The 8 implant abutments designed for the upper implants

Metal framework resting on the implants and natural teeth = trial fitting of the metal framework

 

Metal ceramic crowns designed for implants and natural teeth fastened onto a gypsum cast and artificial gum

 

Cement-retained implant abutments and metal crowns on natural teeth fastened onto a gypsum cast

 

Permanent upper metal ceramic circular bridge retained by 8 implants supplemented with aesthetic, pink gingival ceramics

 


The finished metal ceramic crowns in the mouth

 

Click to see further pictures on the case