Retained alloplastic temporomandibular joint disk implants: A retrospective study

Oral swgery oral medicine oral pathology Withsections

on

endodontics

and

dental radiology

Volume 64. Number 2, August. 1987

oral surgery Editor: ROBERT B. SHIRA, D.D.S.

School of Dental Medicine, Tufts University 1 Kneetand Street Boston, Massachusetts 021 I1

Retained alloplastic temporomandibular joint disk implants: A retrospective study Sidney L. Bronstein, D.D.S., M.Sc.D.* Denver, Colo. UNIVERSITY

OF COLORADO

SCHOOL

OF DENTISTRY

The surgical treatment of intermediate- to late-stage temporomandibular joint disease often involves disk removal. In many instances, disks have not been replaced; long-term postsurgical findings of crepitation and osseous remodeling have been noted although subjective signs and symptoms have been few. Attempts to decrease the noises and bony changes, to enhance biologic resurfacing, and to prevent adhesions, recurrent pain, and dysfunction have prompted many surgeons to use various alloplastic materials to replace the disk, either in a planned permanent (retained) or a planned temporary (retrievable) manner. However, a certain degree of morbidity remains. This article reports clinical responses and radiographic findings in a series of patients who received retained alloplastic temporomandibular joint disk implants. (ORAL SURG.ORAL MED. ORAL PATHOL 1987;64:135-45)

T

he surgical management of internal derangement of the temporomandibular joint (TMJ), as it has evolved over the past 12 years, involves either disk repair and/or reconstruction or disk removal and replacement by either alloplastic or autogenous implants. The alloplastic implants, furthermore, are designated as those planned for indefinite retention or those planned for retrieval a number of months postoperatively. Biomaterials of various configurations have been used with the objectives of promoting biologic resurfacing and preventing adhesions, articular degeneration, crepitus, and pain.‘v2A poll of 37 oral surgeons with large TMJ practices’ revealed that 15 of these surgeons favored the Proplast-Teflon *Associate Professor and Chairman, Division of Oral and Maxillofacial Surgery.

implant after diskectomy while 5 favored the silicone rubber (Silastic) implant. For several years, the alloplastic disk replacement materials most often used have been either Dacron*reinforced Silastictt sheeting, a laminate of Proplast$ and nonporous Teflon?, or a high-performance (HP) Silastic sheeting developed especially for this purpose. The first two materials are placed for, one hopes, indefinite retention1a3*4while the latter one is placed for planned retrieval varying from 2 to 6 months postoperatively.1*5-7

*Dacron polyester fiber (Du Pont Co., Wilmington, Delaware) fTeflon fluorocarbon resins (Dupont Co., Wilmington, Delaware) ttsilastic (Dow Corning, Inc., Midland, Michigan) $PropIast (Vitek Inc., Houston, Texas) 135

136

Bronstein

Oral Surg. August 1987

Table I. Patients receiving disk replacement (from pool of 145 patients representing 215 joints) No. of patients 28 (19%) No. of joints 50 No. of implants 38 (18%)

Table Il.

O-6 7-12 13-18 19-24 25-30 31-36 37-42 43-48

Patients receiving disk replacement

Female = 27 Male = 1 Age: 15-24 6

25-34 8

35-44 10

45-54 2

55-64 2

No material has yet been developed that satisfies all the requirements or an adequate disk replacement implant. Current biomaterials apparently are better tolerated in locations that do not involve joint structures or in situations not subject to loading forces.8m14 Although the large majority of patients whose TMJ disks have been replaced by alloplastic implants are reportedly doing well, I*Wanthe radiographic morbidity seen on followsp examination is causing great concern; some surgeons are of the opinion that all retained alloplastic implants currently available will ultimately fail. Although no time criterion has been specified that would signify therapeutic success, failure is identified by the clinical findings of pain, swelling, open bite and occlusal changes, and by the radiographic findings of sclerosis, erosion, resorption, and regressive remodeling.19-22 The purpose of this article is to (1) report the clinical responses of a group of patients who had received retained silicone rubber, Proplast-nonporous Teflon and Proplast-silicone implants and (2) discussthe use of these implants in light of anecdotal information and published reports of morbid host response.23-26 MATERIALS

Table Ill. Patients receiving disk replacementlength of follow-up (mo.)

AND METHODS

This report is drawn from experiences with 145 patients, representing 215 joints; 28 patients (19%), representing 50 joints, received a total of 38 implants (18%) (Table I). The age and gender distributions are shown in Table II. Table III shows length of follow-up; the types of implants placed are listed in Table IV. Criteria used as indications for placing the implants were as follows: (1) significant anteroposterior or mediolateral dimensional changes of the disk, preventing normal anatomic positioning of the

Patients

Implants

12 5 0 1 2 5 2 r 28

16 8 0 1 2 8 2 -L 38

Patients receiving disk replacement-types and number of implants placed (no. = 38)

Table IV.

Reinforced silicone rubber sheeting HP Silastic Proplast II l Nonporous Teflon ( 16) 0 Silicone (2)

8 (21%) 12 (32%) 18 (47%)

posterior band; (2) various types of disk deformation, especially severe thickening of the posterior band, also preventing a normal disk-condyle-fossa relationship; (3) metaplastic changes causing hardening of the disk or loss of its cushioning nature; (4) severe perforation and degeneration of the disk making satisfactory repair impossible; and (5) reoperation of a previous disk repair/reconstruction. Surgical success was based clinically on the following criteria: (1) 35 mm of opening; (2) lateral excursions of 5 mm; (3) edge-to-edge protrusive relationship; (4) essentially no pain; and (5) the patient’s attaining an acceptable quality of life. Questionnaires, letters, clinical visits, and telephone interviews provided the information with respect to patient progress.Is Bony responses to the implants were evaluated by means of multidirectional multilevel tomography when possible; one patient underwent CT evaluation and one was evaluated with linear tomography. RESULTS

Demographic data, preoperative diagnoses, surgical procedures, clinical courses, follow-up radiographic findings, and other pertinent patient information are summarized in Table V. Clinically, the majority of the patients had ranges of motion and masticatory function acceptable to them even though other criteria of the surgeon were not met.15Compliance with postoperative physical therapy, a soft postoperative diet, and orthotic occlusal stabilization

Retained alloplastic

Volume64

TMJ disk implants

137

Number 2

Fig. 1. Tomograms of right joint with silicone rubber implant showing prominent lipping of condyle, but with smooth, though uneven, contour of superior condylar surface. Prominent concavity in fossa (arrows) relative to the flattened eminence may represent dislodgement and relocation of the silicone rubber implant in the fossa. A, Closed position. B, Open position.

Fig. 2. Tomograms of right (A) and left (B) joints with silicone rubber implants, showing “spur” (large arrow) on lower anterior aspect of right condylar neck. Slightly opaque area in the left joint (small arrows) may represent bony reactive processto the silicone rubber implant.

were instrumental

when the aforementioned criteria

were fully met. Most patients experienced episodes of discomfort that could be attributed to occasional harder foods, increased bruxism without orthotic protection, and a general myofascial response to stress and hyperfunction.15 Radiographic examination showed that the joints with silicone rubber implants had a less disturbing bony erosive response than those with Proplast implants, but there appeared to be areas of radiopacity near the implants that may have represented productive bony reactivity to the material. One was accompanied by rather significant osteophytic condylar spurring (Fig. 1) and, in another case,the bony reaction occurred at the posterior curve of the mandibular notch (Fig. 2). An additional patient exhibited condylar and eminence flattening and scle-

Fig. 3. Linear tomogram of right joint in open position (A), with silicone rubber implant, showing osteophytosis (arrows) of condyle and flattening of eminence. Sclerosis is prominent. Polytome of left joint in open position (B), also with silicone rubber implant, showing loss of condylar substance and opacity in the joint space.

Bronstein

138

Table

V.

Oral Surg. August 1987

Alloplastic retained implants

Patient Age/Gender

Diagnosis stage

Proplast laminate implants (no. = 18) Rt: ADWR, P, L ST 38F Lt: ADWR, P, L

VW 31F SH 47F SF

42F

PF

32F

JM 23F TM 23F KN 40F BR

31F

KS 35F

Postsurgery Ankylosis, L Postsurgery ADWR, P, L; Bilateral Rt: ADR, L Lt: ADR, P, L Rt: ADR, P, L Lt: ADR, I ADWR, L Bilateral* Rt: Postsurgical** Lt: ADR, I Status Postsurgery Rt: ADWR, L/I Lt: ADWR, P, L

ADR, L/I, Bilateral

DW 25F ADWR, L/I KH 39F Silicone rubber (no. = 8) PR 35F ADWR, L Bilateral HH 20F ADR, L/I VL 40F Rt: ADWR, L Lt: ADR, L JM 49F ADWR, P, L Bilateral SS 58M Rt: ADR, L Lt: ADWR, P, L LU 26F ADR, L/I

Procedure

8128185 1 l/7/85 3118186 916185

Diskectomy, right (Fig. 5) Diskectomy, left; Arthroscopy, right Arthroscopy, bilateral Diskectomy, bilateral

9/10/85

Diskectomy,

12/19/84 6/18/86 12/10/83 5125183 2/10/84 2/l l/84

g/3/85

Follow-up ho.)

Rt: 13 Lt: 12

13

bilateral

13

Repair, right Diskectomy, left Diskectomy, bilateral

16

Diskeotomy,

26

4

bilateral

Diskectomy, right (Fig. 6) Repair, left Replace Proplast I, right

32

Repair, right Diskectomy, left; removed 2/86, temporary implants placed bilaterally Diskectomy, right; repair, left (Fig. 7)

30

12

9

7122186 719186

Diskectomy, Diskectomy,

bilateral right; repair, left

6 6

7112182

Diskectomy,

left; repair, right

42

7113183 6121183

right; repair, left (Fig. 1) right (Fig. 4)

32 38

l/7/94

Diskectomy, Diskectomy, Repair, left Diskectomy,

bilateral

(Fig. 3)

34

4116183

Diskectomy,

bilateral

(Fig. 2)

37

1 l/5/84

Diskectomy,

left; repair, right

35

*Right, Teflon; Left, silicone. **Silicone. Diagnosis: ADR = Anterior disk displacement with reduction; ADWR = Anterior disk displacement without reduction; P = Perforation; E = Early stage; E/I = Early intermediate stage; I = Intermediate stage; L/I = Late intermediate stage: L = Late stage. Pain: 1 = Never, 2 = Seldom, 3 = With increased function only, 4 = Always. Diet: 1 = Regular, 2 = Regular Soft, 3 = Soft, 4 = Liquid. Occlusion: 1 = Same as preop; 2 - Open bite, anterior; 3 = Open bite, posterior. Range of motion: 1 = Within criteria, 2 = less than criteria. Radiographic findings: 1 = Flattening, 2 = Erosion, 3 = Sclerosis, 4 = Remodeling, 5 = Osteophytosis, 6 = Degeneration. C = Condyle, E = Eminence, F = Fossa.

rosis but also showed smooth bony contours (Fig. 3). This flattening can also be seen in Fig. 1 along with smooth, but uneven, contours. One unsuccessful result in a patient with late-stage disease who was rather noncompliant with postsurgical management is seen in Fig. 4, with severe loss of joint space and extensive bony remodeling and osteophytosis. The Proplast-Teflon implants produced a more severe bony response of flattening, sclerosis, and

fossa and condylar erosion, exemplified in one patient (Fig. 5); in other cases,less marked reactions were seen radiographically (Figs. 6 and 7). Of the implants placed and reported in this series, only one was removed, a Proplast-nonporous Teflon laminate, after 2 years, representing a 6% removal rate. The silicone rubber implant placed in the joint depicted in Fig. 2 was recommended for removal, but this patient was satisfied with his range of motion

Retained alloplastic TMJ disk implants

Volume 64 Number 2

Maximum opening

Radiographic @dings

Range of motion

Pain

Diet

OCClUSiOn

2, 3

1

1

4

3

15

3-c, E, 5-c

2, 3

2

30

2-c

2

1,

2

1, 2

1

30

2

1

1

>35

5-c

2

1

2 (slight)

>35

1, 3-C, E; 5-C

2

2, 3

1

<30

1, S-C, E

3

1,

2

1

30

1, 2

1

>30

1 1, 2

1 1

(30 35

1, 2

1

<30

l-C, E

1, 2

1

>3s

Lt: 5-c Rt: l-C, E; 5-C 1,4-C, E, F; 5-c; 3-C, E

b-4

1

40

2, 3

20

2

1,

2

>30

2

1, 2

30

1, 2, 3, 4-C, E

Radiograph not available

>35

2

139

CT: I-C, E 1-c; 3-c, E; 5-c

1, 3-C, E 1, 4-C, E; 5-C

Lost to follow-up

and diet and because of severe diabetes mellitus, which was very difficult to control, declined further surgery. Diagnostic arthroscopy of the patient represented in Fig. 5 was obtained 3 months after placement of a Proplast-nonporous Teflon implant. The patient complained of only increasing noises in the joint and denied any pain; she showed acceptable ranges of motion and function. The implant was seen to be in good position (Fig. 8) and was not fragmented or damaged; however, it was not covered with soft tissue. It is apparent that the acceptable clinical progress experienced by these patients for the most part did

not correlate with the morbid radiographic findings, at least at the present length of follow-up. DISCUSSION

In 1981, after the presentation of a paper by Sanders,” the use of silicone rubber replacement implants after TMJ diskectomy became popular; gradually, Proplast II laminated with nonporous Teflon became more desirable. Techniques for placing these implants were also refined and were especially improved with the design for implant retention described by Merrill.’ Furthermore, the Proplast implants offered a choice of thicknesses so that a joint in which the vertical ramus height had been

Oral Surg. August 1987

Fig. 4. Polytomes of right joint with silicone rubber implant, at 4.0 cm levels (A, closed; B, open) and at 3.5 cm level (C, closed; D, open). A and B are more medial than C and D. Flattening of the condylar head and the eminence is prominent but the bony contours appear smooth.

Fig. 5. Polytome of right joint with Proplast-Teflon implant. Preoperative study (A) shows small erosion in superior surface of condylar head. Ten month follow-up(B) shows a more prominent erosion and hypotranslation. Sclerosis is noted in both studies.

decreasedcould be restored to a more normal dimension with a thicker implant (Fig. 6). A presentation in 1983 reported a very large series of Proplast implants that were evaluated as having outstanding clinical and tissue acceptance.17 Sometime in mid-1984, reports circulated anecdotally that the alloplastic implants were showing significant morbidity. Bone was eroding or resorbing; the condyle and the eminence were becoming flattened and sclerotic; patients were reporting pain, swelling, and dysfunction; implants were requiring removal. Some surgeons reported that 20% of their implants required removal because of these symptoms.28 Another report found that 75% required removal: 14 of 22 patients.*’ Well-designed research with respect to tissue responseto alloplastic implants has been scarce, but in 1985 an abstract addressing the subject, later published,23was presented at the annual session of the American Association of Oral and Maxillofacial Surgeons. It reported severe foreign body giant cell reactions (FRGCR) in rabbits to both silicone rubber

Retained alloplastic TMJ disk implants

Volume 64 Number 2

Fig. 6. A, Response of joint at 54 months to 4.3 mm Proplast-silicone implant used to replace right disk and to restore high condylar shave deficit. Osteophytosis is noted. B, Left joint treated by means of disk repair at same time.

141

7. Right joint (A) with Proplast-Teflon implant 9 months postoperatively. Left joint (B) after disk repair at same time.

Fig.

Fig. 8. Arthroscopic photo 3 months after Proplast-Teflon implant was placed in right joint. Same patient as in Fig 5. A, Adhesion (a) between resurfaced condyle (cl and fossa 01. Eminence is identified by letter e. B, Adaptation of implant to fossa and eminence. C, Acceptable resurfacing responseof condyle to implant. A is most anterior, B is more posterior, and C is most posterior of the three.

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Oral Surg. August 1987

Fig. 9. Photomicrograph of joint tissue specimen after removal of Proplast implant. Proplast material and giant cells are noted within the tissue.

Fig. 10. Same patient as in Fig. 9. Photomicrograph of joint tissue specimen after removal of silicone rubber implant. Remnants of silicone rubber implant are located by arrows. Giant cells are seen.

and Proplast-Teflon implants; further evaluation of the use of these materials in human beings was suggested. Other clinicians reported lymph node involvement by implant particles, not only adjacent to the joint areaz4but also at a distance from the joint.25 Clinical results with Propiast I implants for the treatment of facial deformities were deemed good in 87% of the cases in one study,* but these did not involve the implant’s being subjected to joint-loading forces. A similar use of this material for osteoplastic frontal sinusotomy was reported as successful, but

again, no loading forces were affecting the implant; a mild FBGCR was seen but was considered to be a part of the normal healing processa Successful sternum reconstruction has also been reported with Proplast I; a large muscle flap protected this implant.‘O Femoral prostheses coated with Proplast I were placed to study the reaction of human tissue.” “In the most firmly fixed prostheses the ingrowth consisted of fibrous tissue with abundant giant cells; however, no bone growth was detected.” Giant cells were thought to be “an indication of movement of

Volume64 Number 2

Retained alloplastic TMJ disk implants

143

Fig. 11. Arthroscopic photographs of silicone rubber implant, patient in Fig. 9 and 10. A, Tissue proliferation (p) on condylar articular surface (c). B, Loose reinforcing fibers from implant embedded in condylar articular covering (c). C, Tear in the implant (i). D, Adhesion (a) from condylar surface (c) to eminence (e).

the prosthesis rather than a biological reaction” and caused by “micromotion between bone and coating” continuing to occur. Foreign body giant cell reactions to Proplast implants have also been identified by other researchers,‘3,‘4but again these studies did not involve loading forces. A poll conducted by Vitek Inc. in 1986, to which 322 surgeonsresponded, revealed that a total of 6 182 alloplastic implants were placed during the previous 3 years, of which 5644 were considered satisfactory (91%). Criteria for successwere not specified. At the same time, updated guidelines for use of the Proplast implants were also disseminated, outlining quite stringent indications and contraindications, application, postoperative management, and technique; an extensive bibliography of clinical experiences and cautions was also issued with the guidelines. In several series,18, I93** various clinical and radiographic signs and symptoms of postoperative morbidity have been discussed. These included occlusal

changes,deviation on opening, open bite, joint noises, and prolonged joint pain; radiographic changes of sclerosis, flattening, erosion, contour irregularity, lipping, and resorption were also reported. Many factors may be offered as predisposing to increased morbidity with use of an alloplastic implant for TMJ disk replacement. These include (1) preoperative osteoarthritic changes (refer to Fig. 5), (2) decreased vascularity to the condylar head by soft tissue detachment, and (3) abnormal loading forces to the joint postsurgically. This latter factor may either increase potential condylar head resorption or increase fragmentation of the implant to stimulate FBGCR. The disk replacement alloplasts are definitely very “surgically sensitive”;29 techniques of insertion and retention in the fossa and implant design-size and extensions-may

be critical.3, 5

The implants also seem to be very “loading sensitive,“29especially with respect to postoperative occlu-

144 Bronstein sal stabilization, orthotic management, and controlled return to normal function. It appears that with too early or too severeloading the ingrowth into the Proplast implant is decreased;16the viscoelasticity of the implant, however, is improved by tissue ingrowth into the Proplast implant.30Apparently, the FBGCR may also be increased by excessiveloading or loading too early.” Fig. 9 is a photomicrograph of joint tissue removed a few months after Proplast-nonporous Teflon implant placement; it was replaced by a silicone rubber implant. Fig. 10 is a photomicrograph of joint tissue recovered from the same patient after the silicone rubber implant had to be removed a few months later. Arthroscopic evaluation of this patient documented severe perforation of the silicone rubber implant and embedding of Dacron polyester fibers in the articular coverings in parts of the superior compartment (Fig. 11). SUMMARY

AND CONCLUSIONS

What were once thought to be therapeutically well-indicated and exceptionally well-tolerated permanent disk replacement materials are now shown in many cases,for still completely unidentified reasons, to provoke unwanted morbid clinical and radiographic responses. Numerous implants have been removed because of acute symptoms; other require removal becauseof severebony alterations within the joint, causing occlusal or functional discrepancies and/or disorders. A high percentage of cases,however, while showing minor unwanted bony responses and occlusal clinical symptoms, are considered essentially successful by both patient and surgeon. The following conclusions may be drawn: 1. There remains no satisfactory alloplastic replacement material for the TMJ disk. 2. Further research is needed to develop such a replacement and to determine those factors adversely affecting its use in the human TMJ. 3. Patients in whom alloplastic implants have been placed should be closely monitored and implant removal is advised if they become symptomatic; a biopsy of the articular covering tissue should be done when the implant is removed. 4. Permanent replacement of the disk after its removal can be withheld without disabling effects’ or an autologous or freeze-dried tissue implant might be used. 5. Orthotic use to limit joint loading in patients displaying hyperfunctional or parafunctional habits is extremely helpful in the postoperative management.

Oral Surg. August 1987

I gratefully acknowledge the advice and support of colleaguesin the AmericanSocietyof Temporomandibular Joint Surgeonsand in the Farrar-Norgaard Society. REFERENCES 1. Merrill RG. Historical perspectives and comparisons of TMJ surgery for internal disk derangements and arthropathy. J Craniomandibular Pratt 1986;4:74-85. 2. Merrill R. Personal communication. 3. Rippert ET, Flanigan TJ, Middlebrooks ML. New design for Silastic implants in temporomandibular joint surgery. J Oral Maxillofac Surg 1986;44:163-4. 4. Bessette RW, Katzberg R, Natiella JR, Rose MJ. Diagnosis and reconstruction of the human temporomandibular joint after trauma or internal derangement. Plast Reconstr Surg 1985;75:192-205. 5. Dow Corning Corp. Silastic temporomandibular joint implant HP. (Wilkes Design). Product information sheets. 1985. 6. Hall HD. Meniscectomy for damaged discs of the temporomandibular joint. South Med J 1985;78:569-72. 7. Wilkes C. Personal communication. 8. Epstein LI. Clinical experiences with Proplast as an implant. Plast Reconstr Surg 1979;63:219-23. 9. Barton RT. The uses of synthetic implant material in osteoplastic frontal sinusotomy. Laryngoscope 1980;90:47-52. 10. Bell ML. Proplast reconstruction of the lower sternum. Plast Reconstr Surg 1981;68:795-7. 11. Halstead A, Jones CW, Rawlings RD. A study of the reaction of human tissue to Proplast. J Biomed Mater Res 1979; 13:121-34. 12. Rhinelander FW, Stewart CL, Wilson JW, Homsy, CA, Prewitt JM. Growth of tissue into a porous, low modulus coating on intramedullary nails. Clin Orthop 1982;Apr:293305. 13. Kessler FB, Honsy CA, Berkeley ME, Anderson MS, Prewitt JM. Obliteration of traumatically induced articular surface defects using a porous implant. J Hand Surg 1980;5:32837. 14. Arem AJ, RasmussenD, Madden JW. Soft tissue responseto Proplast: quantitation of scar ingrowth. Plast Reconstr Surg 1978;61:214-9. 15. Bronstein SL, Tomasetti BJ. Temporomandibular joint surgery: patient-based assessmentand evaluation. J Am Dent Assoc 1985;110:485-9. 16. Vitek, Inc. Product information. May and October, 1986. 17. Kiersch TA. Abstract. VIII International Conference on Oral Surgery, 1983. 18. Bee DE, Zeitler D. The Proplast-Teflon implant in TMJ reconstruction following meniscectomy. Proceedings, Annual Meeting, Scientific Abstracts, American Association of Oral and Maxillofacial Surgeons, New Orleans, La., 1986:24. 19. Lehnert M. Review of TMJ surgery. Proceedings, Sixth Annual Meeting, Farrar-Norgaard Society, Minneapolis, Minn., 1986. 20. Merrill RG. Contemporary reconstructive arthroplastic procedures.Proceedings, First International Symposium on TMJ Arthroscopy, New York, N.Y., 1986. 21. Helfrick JF. Temporomandibular joint meniscus replacement with allaplasts. Abstract, IX International Conference in Oral and Maxillofacial Surgery, 1986. 22. Florine BL, Gatto D, Wade MJ. Pre- and post-surgical tomographic analysis of TMJ arthroplasties. Proceedings, Annual Meeting, Scientific Abstract Session,American Association of Oral and Maxillofacial Surgeons, New Orleans, La., 1986. 23. Timmis DP, Aragon SB, Van Sickels JE, Aufdemorte TB. Comparative study of alloplastic materials for temporomandibular joint disc replacement in rabbits. J Oral Maxillofac Surg i986;44:541-j4.

Volume 64 Number 2 24. Dolwick MF, Aufdemorte TB. Silicone-induced foreign body reaction and lymphadenopathy after temporomandibular joint arthroplasty. ORAL SURG ORAL MED ORAL PATHOL 1985;59:449-52. 25. Lagrotteria L, Scapino R, Granston AS, Felgenhauer D. Patient with lymphadenopathy following temporomandibular joint arthroplasty with Proplast. J Craniomandibular Pratt 1986;4:172-8. 26. Eriksson L, Westesson P-L. Deterioration of temporary silicone implant in the temporomandibular joint: a clinical and arthroscopic follow-up study. ORAL SURG ORAL MED ORAL PATHOL 1986;62:2-6.

27. Sanders B. Proceedings, AAOMS Clinical Congress, Philadelphia, Pa., 1981. 28. Ryan D. Personal communication.

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29. Kent J. TMJ disorders. Proceedings, Annual Meeting, Colorado Society of Oral and Maxillofacial Surgery, Vail, Cola., 1986. 30. Fontenot MG, Block MS, Kent JN, Homsy CA. Comparison of mechanical properties of the human TMJ meniscus and Proplast II laminates. Proceedings, Abstract Session, AAOMS annual meeting, Washington, DC, 1985. Reprint requests to. Dr. Sidney L. Btonstein 4200 E. 9th Ave., C-284 Denver, CO 80262