this is a journal club presentation on christensen prosthesis system in oral surgery

1. Christensen prosthesis system
Presented by – Dr. Nikita Chhabariya

2. Content
 Introduction
 Articles
 Conclusion
 References

3. Introduction
 Temporomandibular disorders (TMD) are disorders of the jaw muscles,
temporomandibular joints, and the nerves associated with chronic
facial pain. Any problem that prevents the complex system of muscles,
bones, and joints from working together in harmony may result in
temporomandibular disorder.
 The treatment of temporomandibular joint (TMJ) dysfunction resulting from
internal derangement (ID), neoplasia, congenital malformation, or trauma,
as well as osteoarthritis, arthrotic changes, osteochondritis disseccans,
avascular necrosis, and rheumatoid arthritis is a topic of continued debate.

4. The Christensen prosthesis
A retrospective clinical study Donald C. Chase
 Clinical study -patient selection
 Patient selection was based on careful clinical evaluation and objective
evidence of ID or degenerative joint disease with the use of plain films,
arthrograms, and magnetic resonance imaging.
 All patients exhibited significant joint pain and dysfunction.
 Patients were unresponsive to nonsurgical therapies -6 months.
 Pain and function (ability to eat) were measured on a visual analogue
scale (VAS), and incisor opening was measured with a therabite scale.
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY September 1995

5.  These measurements were performed before surgery and 1, 3, 6, and 12 months after surgery,
and annual follow-up examinations given to all patients.
 The majority of patients (77%) had earlier surgical treatment on the diseased joints.
Patients were treated in one of the following ways.
 Placement of the glenoid fossa-eminence---disk retained
 Placement of the glenoid fossa-eminence--disk not retained
 Replacement of the total joint

6. Placement of the glenoid fossa-eminence---disk
retained-
 22 patients and 40joints
 All patients underwent arthroplasty with mobilization of the disk and
disk repositioning when necessary.
 Retention of the disk was determined on the basis of disk quality and
simulated smooth function after placement of a highly polished Co-Cr
glenoid fossa-eminence prosthesis.
 The prosthesis was held in place with bone screws and selected for
maximum coverage of the glenoid fossa-eminence and anatomic fit.

7. Placement of the glenoid fossa-eminence--
disk not retained
 26 patients and 49 joints.
 All patients in this group had conditions that had been
diagnosed as ID, joint dysfunction, or both.
 few showed signs of fibrous ankylosis, and 14 joints (29%)
showed signs of bony ankylosis at the time of surgery.
 All patients underwent arthroplasty with mobilization of
the disk or joint debridement if diskectomy had previously
been performed.
 The prosthesis was selected as in the first group.
 If the disk was still present and showed signs of
perforations, adhesions, or functional interference with the
glenoid fossa-eminence prosthesis, it was removed.

8. Replacement of the total joint
 (21 patients and 34 joints)
 All patients in this group except one with rheumatoid arthritis had
undergone earlier surgical procedures for treatment of ID or
degenerative joint disease.
 In this procedure a glenoid fossa-eminence prosthesis was placed as
described for group 1.
 In addition, the condylar process was replaced with a Co-Cr condylar
prosthesis with a molded PMMA
 centric occlusion with maxillomandibular fixation at the time of
condylar prosthesis placement.

9. Result
 Fossa-eminence with retention of disc- All patients had a significant decrease in pain
significant improvement in the ability to eat.
 Fossa-eminence without retention of disk- surgical placement of a Christensen
fossa/eminence prosthesis in a joint pain except one patient who had no significant
improvement. One patient showed a decreased range of motion postoperatively (31 mm to 30
mm). Two patients required reoperation; one as a result of infection and one because of
improper prosthesis selection.
 Total joint-Ninety five percent of patients showed a significant decrease in pain whereas 10%
showed no significant improvement. Eighty six percent showed a significant improvement in
ability to eat, whereas 14% were not significantly improved.

10. Comparison of 2 Temporomandibular Joint Total
Joint Prosthesis Systems
American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 61:685-690, 2003
The TMJ Concepts total joint prosthesis is a custom-made device constructed from wrought
metals of titanium, titanium alloy, chromiumcobalt alloy (for condylar head only), and
ultrahigh–molecular weight polyethylene. The chromium-cobalt alloy head functions against
the ultrahigh–molecular weight polyethylene.
The Christensen (TMJ Inc, Golden, CO)
total joint prosthesis is an off-the-shelf
device made of cast chromium-cobalt
alloy. The devices used in this study
had a metal condylar head functioning
against a metal fossa.

11.  In this retrospective study, analyzed the treatment records of 45
patients
 The patient population was divided into 2 groups:
Group 1 consisted of 23 patients - CPs
group 2 consisted of 22 patients reconstructed with the TPs total
prosthesis
Both prostheses consisted of a fossa and a mandibular component
 The TP was a custom-made and custom-fitted device derived
from computed tomography (CT) data using -- fabricating an
accurate anatomic plastic model of the patient’s jaws and TMJs.

12.  The prosthesis was constructed on this model. The TP metal
components were wrought, and all parts were machined. The
fossa was made of a commercially pure titanium shell which
allows bone growth into the mesh to maximize stabilization of
the fossa component.
The CP components were off-the shelf products, and all
components were made of cast chromium-cobalt alloy The
fossa component had more than 30 choices of size and shape.
The surgeon selected the best fit intraoperatively.
3-4 fossa
6-8 ramus

13. Results
 The TP group had statistically significant improved outcomes compared with the CP group
relative to postsurgical incisal opening, pain, jaw function, and diet.
 Both groups showed good skeletal and occlusal stability.

14. Temporomandibular joint replacement in
rheumatoid-induced disease
 Patient details-there were six women and only one man (case
4). Ages ranged from 26 to 76 years with a mean of 47.
 Include persistent pain, anterior open bite, and limited opening.
Five patients had total bilateral joint replacement; the other
two had unilateral fossa replacement only.
 These patients can often be managed medically with non-
steriodal antiinflammatory drugs, physiotherapy, and intra-
articular steroid injections
British Journal of Oral and Maxillofacial Surgery (2001) N. R. Saeed
seven patients -temporomandibular joints were
reconstructed using the Christensen Alloplastic Joint
System.

15.  Complications- One patient developed
temporary weakness of the facial nerve and
another patient developed bilateral haeatomas
and Frey’s syndrome.
Objective assessment- by measuring the interincisal
distance before and after operation.
Subjective assessment The preoperative and postoperative
pain and dietary interference visual analogue scores.

16. Patient satisfaction-
Six of the seven patients reported they were very satisfied with their
operation. The remaining patient was satisfied with the joint placed on
the right side but dissatisfied with the joint placed on the left-case 4
there was a slight decrease in pain and patients had
presented with an anterior open bite

17. Result
 All patients showed improved visual analogue scores for pain and dietary
interference after their operations and an improvement in interincisal
distance was recorded in five of the patients.
 Overall satisfaction was high and no patient has rejected the prosthesis
or had any substantial complications.
 The mean follow up period is 30 months (range 8–50).

18. Conclusion
 The Christensen prosthesis are of various modifications they are available in
both forms custom-made and prefabricated in which There is one shape for
the condyle and a choice of40 TO 44 different shapes for the fossa
component. These fossa components are also used for hemiarthroplasty.
 Christensen metal fossa-eminence prosthesis for hemiarthroplasty gives batter
results then the Christensen metal-on-metal total joint prosthesis.

19. References
 The Christensen prosthesis* A retrospective clinical study Donald C. Chase (ORAL SURG ORAL
MEO ORAL PATHOL ORAL RADIOL FNDOD 1995;80:273-8)
 Comparison of 2 Temporomandibular Joint Total Joint Prosthesis Systems American Association
of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 61:685-690, 2003
 Temporomandibular joint replacement in rheumatoid-induced disease British Journal of Oral
and Maxillofacial Surgery (2001) N. R. Saeed
 Factors to consider in joint prosthesis systems Larry M. Wolford, DMD Proc (Bayl Univ Med Cent)
2006;19:232–238

20. Thank-you