Postsurgical Stability of Counter-Clockwise Maxillo-Mandibular Advancement Surgery: Influence of Articular Disc Repositioning

Oral Abstract Session 6 orthognathic surgery. Many of those patients have decreased ramus height, mandibular retrusion and respiratory disturbances due to upper airway obstruction. TMJ total joint prostheses associated with maxillo-mandibular complex advancement improve upper airway space. This study evaluated changes and stability of the oropharyngeal airway, head and cervical posture following simultaneous maxillo-mandibular surgery and TMJ reconstruction with total joint prostheses (TMJ Concepts/ Techmedica Custom-made total joint prostheses). Materials and Methods: Forty-six females, between 14 and 57 years of age, were treated with bilateral or unilateral TMJ reconstruction with total joint prostheses (TMJ Concepts/Techmedica custom-made total joint prostheses), mandibular advancement, maxillary osteotomies and counter-clockwise rotation of occlusal plane angle. The average postsurgical follow-up was 41.5 months. Each patient’s lateral cephalograms were traced, digitized twice, and averaged to estimate surgical changes (T2-T1) and post-surgical changes (T3-T2). To determine the consistency of the method, the two examiners were previously calibrated by repetition of the process until the method was considered adequate by a third examiner. Also, retracing twice each lateral cephalogram evaluated errors in landmark localization (“random error”) during tracing and each lateral cephalometric radiograph got a medium of the measurements. Method of Data Analysis: The intra-examiner consistency (ICC) was calculated for reliability of tracing, landmark identification, and analytical measurements showing a correlation coefficient always greater than 0.94. All data were transferred to SPSS (release 9.0; SPSS Chicago, IL) for statistical analysis. The skewness and kurtosis statistics showed normal distributions for all variables. Differences were initially compared between patients that required coronoidectomy and those that had no coronoidectomy done. Then unilateral and bilateral TMJ prostheses were also compared. Because there were no statistically significant differences between those groups in post-surgical changes, all the patients were analyzed as a single group. Paired t tests were performed to evaluate the surgical (T2-T1) and postsurgical changes (T3-T2). A significance level of P ⬍ .05 was applied. Pearson product-moment correlations were used to determine the relationships between changes of specific anatomical measurements and oropharyngeal airway space changes. Correlations were also used to assess the association between surgical and post-surgical changes in the oropharyngeal airway space. Results: During surgery, narrowest retroglossal airway space (PASnar) changed significantly (p⬍.05), showing an antero-posterior dimension increase of 5.0mm (range3.5 to 15.7mm). The occlusal plane and mandibular plane angles decreased significantly (14.9⫾8.0° and 15.1⫾7.8o respectively) and the maxillo-mandibular complex rotated counter-clockwise. Anterior region of 38.e7

maxilla moved forward (A point 2.5⫾2.3mm, ANS 1.4⫾2.5mm) and upward (A point – 0.9⫾1.9mm, ANS – 0.6⫾1.9mm), while the posterior nasal spine was displaced in a downward and forward direction 5.6⫾4.2 mm and 2.8⫾3.1 mm respectively. The mandible was advanced 17.2⫾7.1 mm at menton, 12.4⫾5.4 mm at B point, 18.3⫾8.6 mm at pogonion and 10.9⫾5.3 mm at gonion. The maxilla and mandible measurements remained stable post-surgery. Head posture (OPT/NS) showed flexure immediately after surgery (-5.6⫾6.8 degrees) and extension post-surgically (1.8⫾6.7 degrees), while cervical curvature (OPT/CVT) had no significant change. The distance between the third cervical vertebrae and menton (C3-Me) and the third cervical vertebrae and hyoid (Hy-C3) increased due to surgery 11.6⫾9.2mm and 3.2⫾3.9mm respectively, and remained stable during the long-term follow-up. The distance from the hyoid to the mandibular plane (MP-Hy) decreased during surgery (-4.0⫾5.7 mm) and after surgery (-2.5⫾5.2mm). Conclusion: Maxillo-mandibular advancement with counter-clockwise rotation and TMJ reconstruction produces immediate increase in oropharyngeal airway dimension, which was influenced by changes in head posture but remained stable over the follow-up period. References Goncalves JR, Buschang P, Gonc¸alves DG, et al. Postsurgical stability of oropharyngeal airway changes following counter-clockwise maxillomandibular advancement surgery. J Oral Maxillofac Surg 2006;64: 755-62 Wolford LM, Cottrell DA, Henry CH. Temporomandibular joint reconstruction of the complex patient with the Techmedica custommade total joint prosthesis. J Oral Maxillofac Surg 1994;52:2-10 Solow B, Siersbæk-Nielsen S, Greve E. Airway adequacy, head posture, and craniofacial morphology. Am J Orthod 1984;86:214 –23

Postsurgical Stability of CounterClockwise Maxillo-Mandibular Advancement Surgery: Influence of Articular Disc Repositioning Daniel Serra Cassano, DDS, 6322 Shady Brook St, Apt 1138, Dallas, TX 75206 (Goncalves JR; Wolford LM; Santos-Pinto A; Marquez IM) Statement: There is controversy as to the appropriate management of patients with pre-existing internal derangement of the temporomandibular joint (TMJ) who require orthognathic surgery for correction of malocclusion and jaw deformities. There are two significantly different philosophies: the first believes that orthognathic surgical procedures reduce or eliminate TMJ dysfunction and symptoms, the second philosophy supports that orthognathic surgery causes further deleterious effects on the TMJ and thus worsens the symptoms and dysfunction post surgery. The second philosophy AAOMS • 2007

Oral Abstract Session 6 proposes surgical management of the TMJ pathology at an initial separate surgical procedure or concomitantly with the orthognathic surgery. Some authors recommend that patients with co-existing TMJ dysfunction and skeletal facial deformities undergo orthodontic preparation followed by orthognathic surgery. For the small number of patients whose TMJ symptoms do not resolve and are too severe to undergo orthodontic preparation for orthognathic surgery, TMJ surgery may be performed before orthognathic treatment. However, other studies have shown that concomitant surgical correction of TMJ pathology and coexisting dentofacial deformities, in one operation, provides highquality treatment outcomes for most patients relative to function, aesthetics, elimination or significant reduction in pain and improved patient satisfaction. Materials and Methods: Seventy-two patients (59 females, 13 males), with an average age of 30 years (range 15 to 60 years). The patients were divided into 3 groups. Group 1 (G1) (n ⫽ 21) with healthy TMJs received double-jaw surgery only; Group 2 (G2) (n ⫽ 35) with articular disc dislocation received articular disc repositioning with the Mitek anchor technique concomitantly with orthognathic surgery; and Group 3 (G3) (n ⫽ 16) with articular disc dislocation received orthognathic surgery only. Average post surgical follow-up was 31 months. Each patient’s lateral cephalograms were traced, digitized twice, and averaged to estimate surgical changes (T2-T1) and post surgical changes (T3-T2). Method of Data Analysis: After being collected from DFPlus software (Dentofacial Software Inc, Toronto, Canada), all the data were transferred to SPSS (release 11.5; SPSS, Chicago, IL) for statistical analysis. One sample t test was performed to evaluate the surgical (T2-T1) and post surgical changes (T3-T2). Differences were then tested among G1, G2 and G3 by analyses of variance (ANOVA) and Tuckey test. A significance level of p ⬍ .05 was applied. Pearson product-moment correlations were used to determine the relationship between changes of specific anatomical measurement used to compare post surgical changes in each group. Results: During surgery, the occlusal plane angle decreased significantly in all three groups; G1 (-6.3 ⫾ 5.0°), G2 (-9.6 ⫾ 4.8°), and G3 (-7.1 ⫾ 4.8°). The maxillomandibular complex advanced and rotated counter-clockwise similarly in all three groups, with advancement at menton in G1 (12.4 ⫾ 5.5 mm), G2 (13.5 ⫾ 4.3 mm), and G3 (13.6 ⫾ 5.0 mm); B point in G1 (9.5 ⫾ 4.9 mm), G2 (10.2 ⫾ 3.7 mm), and G3 10.8 ⫾ 3.7 mm); and lower incisor edge in G1 (7.1 ⫾ 4.6 mm), G2 (6.6 ⫾ 3.2 mm), and G3 (7.9 ⫾ 3.0 mm). Post surgery, the occlusal plane angle increased in G3 (2.6 ⫾ 3.8°) while G1 and G2 remained stable. Mandibular post surgical changes, in the horizontal direction, had a larger relapse in G3 at menton (-3.8 ⫾ 4.1 mm), B point (-3.0 ⫾ 3.4 mm), and AAOMS • 2007

lower incisor edge (-2.3 ⫾ 2.1 mm) while G1 and G2 remained stable. Conclusion: Maxillo-mandibular advancement with counter-clockwise rotation of the occlusal plane is a stable procedure for patients with healthy TMJs or for patients with simultaneous TMJ disc repositioning using the Mitek anchor technique. Patients with preoperative TMJ articular disc displacement who underwent doublejaw surgery and no TMJ intervention experienced significant relapse. References Wolford, LM: Concomitant Temporomandibular Joint and Orthognathic Surgery. J Oral Maxillofac Surg 61:1198-1204, 2003 Wolford LM, Reiche-Fischel O, Mehra P: Changes in TMJ dysfunction after orthognathic surgery. J Oral Maxillofac Surg 61:655, 2003 Hoppenreijs TJM, Stoelinga PJW, Grace KL, Robben CMG: Long-term evaluation of patients with progressive condylar resorption following orthognathic surgery. Int J Oral Maxillofac Surg 28:411-418, 1999

Stability of Maxillo-Mandibular CounterClockwise Rotation and Mandibular Advancement With TMJ Concepts Total Joint Prosthesis Octavio Margoni-Neto, DDS, Rua Onze de Agosto, 72, Santo Andre, Sao Paulo, 09110-170, Brazil (Wolford LM; Dela Coleta KE; Goncalves JR; Santos-Pinto A; Pinto LP) Statement: Temporomandibular joint (TMJ) pathology can create clinical problems that can also involve the masticatory musculature, jaws, occlusion, and other associated structures. Degenerative pathological processes of the condyles may require TMJ reconstruction and orthognathic surgery to achieve optimal functional and esthetic results.This study evaluated maxillo-mandibular surgical changes and stability following TMJ reconstruction and mandibular advancement with custom-made TMJ total joint prostheses (TMJ Concepts/Techmedica) and maxillary osteotomies performed at one operation. Materials and Methods: Forty-seven females, between 14 and 57 years of age, were treated with bilateral (n⫽42) or unilateral (n⫽5) TMJ reconstruction and mandibular advancement with total joint prostheses, as well as maxillary osteotomies and counter-clockwise rotation of occlusal plane angle. The average postsurgical follow-up was 3.4 years (range 1 to 11.9 years). Each patient’s lateral cephalograms were traced, digitized twice, and averaged to estimate surgical changes (T2-T1) and post surgical changes (T3-T2). Method of Data Analysis: All data were transferred to SPSS (release 9.0; SPSS Chicago, IL) for statistical analysis. The skewness and kurtosis statistics showed normal distributions for all variables. Paired t tests were performed to evaluate the surgical (T2-T1) and postsurgical changes (T3-T2). A significance level of P ⬍ .05 was 38.e8