Condylar response to large mandibular advancement combined with maxillary impaction and counterclockwise rotation: A computed tomographic study

Abstract

BackgroundThis study aims to analyze the effectiveness of cone-beam computed tomography (CBCT) in the evaluation of the condylar position, angulation and intercondylar distance and assess the changes in these parameters before and after bimaxillary surgery, preformed with the critical movments of Le Fort I osteotomy (for impaction of the maxilla and conterclockwise rotation of the upper occlusal plane) and Bilateral Sagittal Split Osteotomy (BSSO) for mandibular advancement (> 8mm).Material and MethodsTwenty class II patients successfully treated with BSSO of the mandible, in conjunction with Le Fort I osteotomy, were studied to evaluate the condylar changes before and after surgery. The position of the condyle was classified according to the Pullinger & Hollender’s formula in both phases. A MANOVA analysis followed by post-hoc tests were conducted to ascertain if there were statistically significant differences between pre and post surgical variables under study. The agreement of the condylar position’s classification was evaluated resorting to the Kappa statistics.ResultsThere were no statistically significant differences between the values of the position and angulation of the condyles and intercondylar distance before and after surgery. There was an increase of the axial angle of the left condyle and the frontal angle of both condyles, while there was a decrease of the axial angle of the right condyle, the sagittal angle of both condyles and intercondylar distance.ConclusionsThe CBCT is a useful method for assessing variations of condylar position in detail. It was verified that the critical movements of maxillary impaction associated with the mandibular advancement do not produce significant alterations in the mandibular condyles, however, these tend to perform a posterior and inferior movement. Key words:Cone-Beam computed tomography, orthognathic surgery, mandibular condyle, osteotomy, le fort, temporomandibular joint.

Modeling the effect of bilateral sagittal split osteotomy on posterior, superior and medial space dimensions of the temporomandibular joint: a retrospective controlled cohort study

“…The role of condylar rotation after mandibular advancement has been discussed controversially. Although some authors described that the use of fixation, including positional screws [ 13 ] and miniplates [ 58 , 59 ] for BSSO provoked inward condylar rotation and medial condylar displacement, others reported that in BSSO for mandibular advancement the fixation with miniplates [ 16 ] had no significant effect on the corresponding condylar changes. However, it is known that mandibular advancement usually produces greater condylar displacement if the anterior osteotomy gap is forcefully closed with rigid fixation [ 60 , 61 ].…”

“…The application of CBCT has been reported for determining changes in condylar position after bilateral sagittal split ramus osteotomy (BSSO) for mandibular advancement, without [9][10][11][12][13][14] or with [15][16][17][18] a LeFort I osteotomy. According to these studies, condylar displacement after mandibular advancement surgery is variable.…”

Evaluation of the Mandibular Condyle Morphologic Relation before and after Orthognathic Surgery in Class II and III Malocclusion Patients Using Cone Beam Computed Tomography

“…Vale et al, aiming to analyze the effectiveness of CBCT in evaluating the condylar position, angulation, and intercondylar distance and to assess the changes in these parameters before and after bimaxillary surgery in class II patients, showed that the surgery did not significantly change the mandibular condyles. However, they tended to migrate inferiorly and posteriorly [ 32 ]. These findings are equivalent to the current study’s findings for patients with class II malocclusion.…”

Condylar Changes after Maxillary Expansion in Children with Cleft Lip and Palate—A Three-Dimensional Retrospective Study

“…Subsequently, the variables were measured according to the methods defined by Vale et al [ 23 ]. All measurements were performed by a single authors follows:…”

“… CBCT image evaluation: ( a ) midpoints of reference; ( b ) Frankfort horizontal plane; ( c ) midsagittal plane; ( d1 ) intercondylar distance; ( d2 ) condylar angulation in the axial plane; ( d3 ) condylar angulation in the frontal plane; ( d4 ) condylar angulation in the sagittal plane; ( d5 ) condylar position in the sagittal plane. Adapted from Vale et al [ 23 ]. …”