Maxillomandibular Plane Angle Bisector (MM) Adjunctive to Occlusal Plane to evaluate Anteroposterior Measurement of Dental Base

Abstract

Aim This study was undertaken to analyze the clinical usefulness of the maxillomandibular bisector, its reproducibility, its validity and its relationship to the functional occlusal plane, the bisecting occlusal plane and the nature of its cant. Materials and methods Thirty pretreatment lateral cephalograms, each of adolescents (above 18 years of age) and children (10- 12 years), seeking orthodontic treatment were randomly selected and the Wits technique of anteroposterior measurement was used to compare A-B values measured to the new plane with those measured to the functional occlusal plane (FOP) and to the traditional or bisecting occlusal plane (BOP). Results Present study showed that MM bisector plane is more reproducible and valid reference plane, than the FOP and BOP. Conclusion A new plane, geometrically derived from the dental base planes, has been tested as an occlusal plane substitute for the measurement of anteroposterior jaw relationships. It lies close to but at an angle and inferior to the traditional occlusal planes and is highly reproducible at all times. Clinical significance Maxillomandibular planes angle bisector may be a useful adjunct for the cephalometric assessment of sagittal relationship of the patient. How to cite this article Ganiger CR, Nayak USK, Cariappa KU, Ahammed ARY. Maxillomandibular Plane Angle Bisector (MM) Adjunctive to Occlusal Plane to evaluate Anteroposterior Measurement of Dental Base. J Contemp Dent Pract 2012; 13(4):539-544.

The maxillary-mandibular planes angle (MM?) bisector: A new reference plane for anteroposterior measurement of dental bases

“…This study is in concordance to our study. Scott JH, 11 Ganiger RC (2012) 1 found that AB-MM is more reliable because the MM bisector is highest stable plane with the relation of cranial base. It is recommended that the orthodontist can use AB-MM parameter for judging the anterio-posterior skeletal discrepancy with better accuracy and validity than its contemporary parameters.…”

“…Diagnosis of an important part of orthodontic treatment and the greatest thrust in this direction evolved with advent of radiographic cephalometry by Broadbent in 1931. 1,2 Although many cephalometric analysis have been devised to determine the degree of anteroposterior skeletal discrepancies, effective treatment planning and assessment must be based on accurate measurement using stable and reproducible reference planes. Despite the popularity of the ANB angle, 1 Jacobso 3 noted that this measurement does not always accurately relate the true anteroposterior relationship of the jaws.…”