Scientific Poster Session

(232 teeth) received a prescription for CR and were instructed to use it for two weeks post operatively according to directions (30-second oral rinse twice daily, using 15 ml each time). The remaining 175 patients (306 teeth) received a single oral rinse (15 ml of CR) immediately prior to the extraction. Except for the use of the CR, procedures for all groups were the same. Extraction was carried out by one surgeon using a standardized surgical technique. The socket was irri- gated with copious sterile water and a 6 mm Gelfoam cube impregnated with 75 mg of tetracycline was then inserted into the depth of the socket and the incision closed with two 3-O silk sutures. Patients received 10 mg of dexamethasone intravenously immediately following extraction. A0 was defined as postoperative pain and loss of the clot upon clinical exam.

There were 14 A0 in 91 extraction sites in the group not treated with CR and 41 A0 out of 306 extraction sites in the group treated with a single preoperative rinse. There were 232 extraction sites in the group who used the CR for two weeks following extraction 18 of these extractions resulted in AO. This was statistically significant (p < 0.05) using a comparison of two bino- mial distributions. These findings conclude that 0.12% chlorhexidine (Peridex) used for two weeks post- operatively significantly (50%) reduced the incidence of A0 after the extraction of impacted mandibular molars.

References

Nordenram, A., Grave, S.: Alveolitis sicca dolorosa after removal of impacted mandibular third molars. Int J Oral Surg 12:266,1983

Awang, M.: The aetiology of dry socket. Int Dent J 39:236,1989

POSTER 3 Long-Term Evaluation of Mandibular Cody&w Process Fractures Nicholas J. Boumias, DDS, Div. of OMS, Henry Ford Hospital, 2799 W. Grand Blvd., Detroit, MI 48202-2689 (Christian, J.M., Tucker, S.A.)

Management of mandibular condylar process frac- tures has been controversial-whether treatment should be by open or closed reduction. The purpose of this study is to assess the long term morbidity associated with closed reduction methods. A retrospective review of patient charts from years 1983 to 1989 was undertaken; criteria for selection included unilateral or bilateral mandibular condylar process fractures, radiographic displacement, and treatment with closed reduction. 50 patients with the required criteria were contacted and 4 patients responded. The patients studied were male with a range in age from 21-70 years. The length of follow-up ranged from 2-7 years. A questionnaire was utilized that

included date of injury, treatment, follow-up, pain, joint noise, and limitation of movement. Collection of objec- tive data consisted of recordings of maximum mandibu- lar opening, lateral movement, and Angle classification; and radiographs which included panorex, PA and lateral cephalometric views.

Results: Of the four patients studied, two were injured in an altercation, one in a work-related accident, and one in a motor vehicle accident. Only one patient sustained a concomitant parasympheseal fracture. Three of the four patients reported no subjective complaints of pain, joint noise, or limitation of movement. The other patient, involved in a motor vehicle accident; com- plained of limited jaw opening, and joint noise associ- ated with pain. Three of the four patients had normal maximum mandibular opening (38-55MM) with no devi- ation, and normal lateral excursions. No pain was elicited during manual palpation of temporalis, medial pterygoid and masseter muscles. The other patient had a 25 mm MM0 with 3 mm right and left lateral excursions. Radiographically, full osseous continuity was noted in all patients with radiographic evidence of remodeling noted in 3 patients. One patient had an anteriorly- displaced condylar fracture which healed with the condy- lar head remaining anterior to the articular eminence.

Conclusions: The temporomandibular joint and condy- loid process are an unusual portion of the skeletal system because of their ability of repair after injury$ this long term investigation reinforces the conservative meth- ods of treatment’ since: 1) 3 of 4 patients denied any pain, joint noise, or limitations of movement; 2) 3 of 4 patients had normal mandibular opening with no devia- tions, normal lateral excursions, and no palpable pain; and 3) radiographic evidence in all patients showed good osseous healing. A lack of participation in this study limited the number of subjects for investigation. This most likely reflects acceptable treatment results; how- ever, efforts are ongoing to increase the participation with newer patients to corroborate these findings.

References

Blevins, S.: Fractures of mandibular condyloid process results of conservative treatment in 140 patients. J Oral Surg 30:394,1%1

Lindahl, L.: Condylar fractures of the mandible. Int J Oral Surg 639s203,1977

POSTER 4 Prediction of Ramus Fmgment Rehztiomhip in the Surgical Correction of FacidAsymmetries Joe Hall Morris, DDS, 875 Union Ave., Memphis, TN 38163 (Brooks, J., Albright, S.E., Naito, R.)

Accurate diagnosis and treatment planning are criti- cal to the successful surgical outcome of patients with

114 MOMS . 1991

Scientific Poster Session

canted occl& planes, laterognathia and/or bypass bites. A three-dimensional understanding of the skeletal and dental deformity is mandatory in the presurgical evaluation of such patients. Conventional dental articu- lators are limited in th& true representation of the individual craniofacial skeleton in that the intercondylar distance and the correction for earpost to condylar axis is set only to approximate that found in the average adult. Conventional articulators do not accurately repre- sent true autorotation of the mandible. Conventional model surgery on such articulators does not allow presurgical visualization of the mandibular ramus or address proximal and distal fragment relationship follow- ing ramus surgery. The choice of ramus procedure, the necessity for bone grafting and fragment contouring, and the feasibility of rigid flxation therefore tend to be arbitrarily determined. The Orthognathic Surgery Simu- lating Instrument (O.S.S.I.), designed by Dr. Joe Hall Morris, allows the surgeon to more easily plan surgical corrections in the laboratory with a greater degree of accuracy and ultimate clinical simulation.

Since its development sixteen years ago, the O.S.S.I. has been used at our institution to plan surgical correc- tion for patients with facial asymmetries. The initial patient evaluation includes clinical and radiographic studies comprised of submentovertex, lateral cephalomet- ric and panorex radiographs. The intercondylar distance and condylar axis from the earpost offset is measured from these radiographs with correction for magnifica- tion and is then transferred to the instrument. The casts are mounted on the O.S.S.I., and the customized facsim- ile rami are secured to the mandibular cast. Following maxillary repositioning, surgical cuts are made on the facsimile rami and the mandible is then repositioned. Characteristics of the occlusion, ramus fragment relation- ships, amount of bone grafting needed, necessity for fragment contouring, and feasibility of rigid fixation can then be assessed.

An accurate three-dimensional representation of the rami, condyles, intercondylar distance and true rotation of the mandible on the condylar axis allowed for more accurate and reliable treatment planning. Some of the advantages found using the O.S.S.I. in treatment plan- ning for these patients with facial asymmetries included a more appropriate selection of ramus procedure based on overall ramus fragment apposition. Clinically insignif- icant changes in the final occlusion could be adjusted to allow for a better ramus fragment relationship. Case planning for the correction of asymmetries of the poste- rior maxilla in the horizontal plane revealed that often poor fragment relationship was translated to the mandi- ble. This may have led to compromised facial esthetics, delayed healing, and difficulty in application of rigid fixation. Visualizing such outcomes pre-operatively al- lows for appropriate adjustments in the position of the

maxilla or mandible. Decreased surgical time due to pre-operative knowhxlge of the necessity for and amount of bony contouring and bone gmfting is also an advan- tage. In our patient population, close correlation was consistently evident in the comparison of facsimile ramus to intraoperative ramus fragment positions.

References

Hill, S.C.: Cepbalometric planning and model surgery, in Bell W.H. (ed): Surgical Correction of Dentofacial DefomdtiekNew Concepts. Phiidalphia, PA, Saunders, 1985, pp 217-226

Ellis, E.: Use of the orthoguathic surgery simulating inatrument in the presurgical evaluation of facial asymmetry. J Oral Maxillofac Surg 42:805,1984

Departmental funding

POSTER 5 Getmmid Gnas- of D&c Re~idoning Pmcedms Leslie B. Heffez, DDS, MS, Univ. of Illinois, Dept. of OMS, 801 S. Paulina St., Chicago, IL 60680 (Crawford, G.L., Jordan, S.)

Disc repositioning procedures have been advocated for the treatment of internal derangements of the temporomandibular joint. Arthroscopy has again brought into question the feasibility and efficacy of repositioning displaced discs. In this study we critically evaluate the geometry of repositioning discs using cadaver and mag- netic resonance (MR) image models.

Lateral, central, and medial sag&al planes of four histologic specimens and five MR images were utilized yielding 27 sections/images. These specimens/images were projected at a standard magnification of 7.3. The posterior attachment-disc-condyle-glenoid fossa relation- ships were then traced onto acetate paper. Mock disc repositioning surgery was performed for each serial histological section and image. The disc was reposi- tioned to a standard location as determined by a previously designed model. The following measure- ments were then obtained: anterior capsule to most anterior aspect of repositioned disc and length of poste- rior attachment resected. Additional observations were made including the necessity of discoplasty or deforma- tion (bending) at the thin zone to permit the disc to geometrically fit into the available joint space. The data from the lateral, central, and medial sections was cor- rected to represent actual measurements and analyzed.

In accomplishing mock surgery and analyzing the data, only geometrical aspects of the procedure were considered. Viscoelastic molding of the disc to existing joint space was not considered. Results from the study

MOMS . 1991 115