3-Dimensional CBCT analysis of mandibular asymmetry in unilateral condylar hyperplasia.
OBJECTIVE
Three-dimensional quantification of asymmetry in UCH has not been reported yet, but would be useful for diagnosing and evaluating the degree of deformity in this disease. It enables profound decision-making and timing of surgery. Unilateral condylar hyperplasia (UCH) can subjectively be classified in hemimandibular elongation (HE), hemimandibular hyperplasia (HH) and a combination of these two (hybrid form). The main purpose of this study was to quantify mandibular asymmetry in UCH patients with a reliable and reproducible method. Secondly, it was evaluated whether the existing classification can be confirmed.


METHODS
37 UCH-patients with progressive mandibular asymmetry, supported by a positive bone scan and/or such clinical progression that condylectomy was performed, were included in this retrospective study. A group of healthy subjects, matched for age and gender, was used as the control group. Cone-beam computed tomography (CBCT) scans were imported in Maxilim®software. Each mandibular half was divided into three skeletal segments (condyle, ramus, and body). Linear and volumetric measurements were calculated for these skeletal units on the affected and unaffected side, for both patients and controls.


RESULTS
Significant differences between affected and unaffected sides in the patient group were found in condylar, ramus, and body segments for linear (p < 0.01) as well as for volumetric quantitative measurements (p < 0.0040). A mean linear difference between affected and unaffected sides in the condylar region of the UCH patient group was found of 3.6 mm (sd 2.9) versus 0.2 mm (sd 1.5) in controls. For volumetric measurements there was a mean difference between the left and right condyle of 718 mm3(sd 638) in the patient group versus 8 mm3(sd 225) difference in the control group. The condyle was the most affected segment. Differences between sides were significantly larger in the patient group than in the control group (p < 0.001). It was not possible to objectify differences between HE and HH.


CONCLUSIONS
CBCT is a useful and accurate modality for quantification and evaluation of mandibular asymmetry in UCH. It enables objective monitoring. The existing classification in HE and HH could not be confirmed.
Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. J. de Lange), Academic Medical Centre/Emma Children's Hospital, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. Electronic address: j.w.nolte@amc.nl.
Jitske Willemijn
JW
Nolte
Department of Oral and Maxillofacial Surgery, Radboud University Medical Centre, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands.
Tim Jan
TJ
Verhoeven
Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. J. de Lange), Academic Medical Centre/Emma Children's Hospital, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands; Department of Oral and Maxillofacial Surgery, Radboud University Medical Centre, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands.
Ruud
R
Schreurs
Department of Oral and Maxillofacial Surgery, Radboud University Medical Centre, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands.
Stefaan Jozef
SJ
Bergé
Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. J. de Lange), Academic Medical Centre/Emma Children's Hospital, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
Luc Hendrikus Elisabeth
LH
Karssemakers
Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. J. de Lange), Academic Medical Centre/Emma Children's Hospital, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands; Department of Oral and Maxillofacial Surgery, Spaarne Gasthuis, Boerhaavelaan 22, 2035 RC, Haarlem, The Netherlands.
Alfred Gustaaf
AG
Becking
Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. J. de Lange), Academic Medical Centre/Emma Children's Hospital, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands; Department of Oral and Maxillofacial Surgery, Radboud University Medical Centre, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands.
Thomas Jan Jaap
TJ
Maal
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000000981:diagnostic imaging*; D021621:Imaging, Three-Dimensional; D008297:Male; D008334:Mandible / Q000002:abnormalities* / Q000000981:diagnostic imaging; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000473:pathology*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
CBCT; Mandibular asymmetry; Mandibular volume; Three-dimensional; Unilateral condylar hyperactivity; Unilateral condylar hyperplasia