Case 9 Quad with 2 zygoma and 2 pterygoid implants

Quad case with 2 long implants in the zygomatic bone and 2 long implants in

the pterygoid bone

Dr Luc Vrielinck MD DDSOral and Maxillofacial Surgery

Comments at [email protected], Belgium

mailto:[email protected]

Starting point

• Patient desires: fixed prosthesis in the upper jaw

• Status: Division D atrophy in upper jaw• Treatment plan:

– Quad long implant placement, delayed loading

– Overdenture on a bar

Chronology• 24/04/2008: Placement QZ• 21/10/2008: Second stage QZ• 19/01/2009: final work• Complication: persistent paresthesia of the left maxillary

nerve (see the matching of preoperative and postoperative images)

• 23/08/2010: 22 months follow-up

13/11/2007: Intake

13/11/2007: Intake

13/11/2007: Intake

16 15 14 13 12 11 21 22 23 24 25 26H - - - 2.9 6.5 3.4 3.9 3.9 4.6 - - -

T - - - 2.0 4.2 3.5 2.5 3.6 3.3 - - -

H= height of the bone, T=thickness

Bone table: analysis of thickness and height (in mm) on following tooth positions

Treatment plan

Based on the data of the bonetable the treatment plan was decided on 2 long implants with zygomatic anchorage and 2 long implants with pterygoid bone

anchorage

01/02/2008: Planning of the implants using Procera™ Software












• Problem: the drilling directions of both zygoma implants cross each other

• In the Surgical Template; the extension sleeves collide with each other and by consequence the Surgical Template cannot be fabricated

• Solution: the implant treatment is splitted over two Surgical Templates, using the same position of the anchor pins


Drillguide 1: including left zygoma implants and both posterior implants


Drillguide 2: including right zygoma implant using same anchor pin anchorage as the first dill guide

Surgical technique used in this case

• The Surgical Template N°1 was fixed using a surgical index (under local anaesthesia, with patient sitting

• Patient was then brought under general anesthesia• The drilling of 3 implants was done using Surgical

Template No 1• Surgical Template n°1 was removed and replaced by

Template N°2 using the same anchor pins• Right zygoma implant was drilled• Surgical Template was removed • Implants were placed freehand

24/04/2008: Postoperative imaging

Here we have an obvious problem !Apparent correct position ofboth implants

24/04/2008: Postoperative imaging

Here we have a problem !

29/10/2008: Pre post matching

Frontal view Occlusal view

Distal displacement of the tip of the rightZygomatic implant

Orange= planned position; Yellow = placed position

Top view Left lateral view

Orange= planned position; Yellow = placed position

Cranial displacement of the tip of the left implant with pterygoid anchorage

Discussion of the Surgical Outcome

• 2 out of 4 implants demonstrate a deviation of the tip of the implant of > 1cm resulting in:– for the right zygoma implant: an emergence

of the implant posterior of the zygomatic bone– For the left pterygoid: cranial tilting of the

implant; the tip of the implant entering the pterygopalatine fossa, causing laesion of maxillary nerve (V2)

21/10/2008: second stage surgery

23/08/2010: Follow-up 22 months










Very good occlusal distribution of forces





Documents

Case 9 Quad with 2 zygoma and 2 pterygoid implants