Screw-retained implant bridge (case study)

Our male patient, 67, presented to our clinic with the following complaints:

• Earlier he had to have his lower right teeth number 6 and 7 (first and second molar) extracted.
• Following several months’ healing he desired to have his missing teeth replaced with implants and have beautiful teeth again. The implant has the advantage that it is inserted into the bone with a crown screwed on without filing down (preparing) sound, adjacent teeth for a bridge.
• He was greatly disturbed by not being able to chew properly on the right side, and by overloading the left quadrants he was running the risk of damaging his remaining teeth and the temporomandibular joint in the long run.

  First encounter: The patient turned up at the first encounter already with a CBCT (Cone beam computed tomography) scan on hand to help us examine residual bone mass in 3 dimensions prior to implant surgery. Based on the CT scan both bone height and bone width were adequate for the installation of implants. Our patient opted for the high-end Straumann implants. Since the primary stability of the implants was over 30 Ncm when installed, the patient received gingiva formers (healing abutments) to ensure a perfect gum contour for the permanent abutments.   Second treatment: Following the mandatory 3 months’ healing period we set about fabricating the permanent replacements. Our patient selected a screw-retained implant bridge due to its low repair costs. Should any issue arise with the implants or the ceramic bridge, etc. over the years, a screw-retained implant bridge can be removed and the implant underneath can be treated and the same bridge can be screwed back on on completion of the treatment. No need to make a new bridge over again. Precision impressions were taken of the implants with closed tray impression copings. The dental technician got a full picture of the position of the implants and the surrounding teeth, and could fabricate an accurate and matching crown.  

Lower right Straumann implants (with closed tray impression copings (see left) on a panoramic radiograph recorded prior to impression taking.

  The finished bridge need only be screwed in place and the slot of the through bolts sealed with a filling. On the top of the screw-on bridge there is a small slot through which the bridge is screwed in place. This slot is then sealed with an aesthetic filling. Sadly the composite filling will not always seal with 100% precision, the slot may be discernible to a minimal extent, but only by those “looking to find” fault with the tooth. Under normal circumstances the colour disparity caused by this small slot is indistinguishable during speech or laughter. IMPORTANT NOTICE Implant-borne tooth replacements require as much, if not more care and follow-up as natural tooth-borne bridges and crowns. There is a very close relationship between oral hygiene and the long-term success of implants.

When fabricating a tooth replacement an antagonist impression is taken of the opposite jawbone whereby the dental technician can determine the occlusal relationships and opposite teeth.

 

Closed tray precision impression taken of the 2 Straumann implants.

 

Precision impression of the 2 Straumann implants with the closed tray impression copings (upper view)

 

Precision impression of the 2 Straumann implants with the closed tray impression copings (side view)

 

Bite registration: the relationship between opposite teeth is recorded by means of a silicone bite registration material

 

The completed silicone bite registration with the help of which the dental technician can accurately determine the occlusion of opposite teeth

 

Side view of the finished metal-ceramic screw-retained implant bridge on Straumann implants on a gypsum cast

 

Upper view of the finished metal-ceramic screw-retained bridge on Straumann implants on a gypsum cast

 

Side view of the finished metal-ceramic screw-retained bridge on Straumann implants on a gypsum cast with the screw driver securing the through bolt

 

Follow-up panoramic radiograph of the finished metal-ceramic screw-retained bridge on Straumann implants