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 DDS Oral and Maxillofacial Surgery Comments at Luc@Vrielinck.be Genk, Belgium

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

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

16

15

14

13

12

11

21

22

23

24

25

26

H

-

2.9

6.5

3.4

3.9

4.6

-

T

-

2.0

4.2

3.5

2.5

3.6

3.3

-

H= height of the bone, T=thickness

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

Treatment plan

01/02/2008: Planning of the implants using Proceraâ&#x201E;˘ 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

01/02/2008: Planning of the implants using Proceraâ&#x201E;˘ Software

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

01/02/2008: Planning of the implants using Proceraâ&#x201E;˘ Software

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

Apparent correct position of both implants

Here we have an obvious problem !

24/04/2008: Postoperative imaging

Here we have a problem !

24/04/2008: Postoperative imaging

Orange= planned position; Yellow = placed position Frontal view

Occlusal view

Distal displacement of the tip of the right Zygomatic implant 29/10/2008: Pre post matching

Orange= planned position; Yellow = placed position

Top view

Left lateral view

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)