Steiner Analysis Cecil C.docx

Steiner Analysis Cecil C. Steiner (1896-1989) one of Edward H. Angle's first students in 1921. He developed a form of cephalometric analysis, presented in 1953, referred to as the Steiner method of analysis. He used the Ribbon Arch, as taught by Angle, for many years, and he helped Angle file out some of the first Edgewise Brackets.

Steiner Analysis Steiner approached and propagated cephalometrics for effective use in treatment planning and not merely a diagnostic tool. Steiner selected parameters from various analysis developed by several authors, critically evaluated, modified and included them in his analysis. Steiner proposed the appraisal of various parts of the skull separately as: 1. Skeletal analysis 2. Dental analysis 3. Soft tissue analysis

SN plane substituted FH plane

Steiner in his analysis took into account that it may not be possible to reach ideal Proportions and relationships in all cases, but there are ways to maximize esthetics. Steiner devised ways to alter incisor positions to achieve normal occlusions even when the ideal ANB angle couldn’t be achieved. i.e how much the teeth needed to be moved to compensate for a skeletal malocclusion. For larger skeletal discrpancies, the steiner method would not be effective for treatment. Dental Camouflaging may be able to make up for the skeletal discrepancy.

Steiner’s Analysis (1953) Skeletal Analysis (Sagittal ) SNA SNB ANB Skeletal Analysis (Vertical) Mandibular plane angle (SN-Mand plane) Y-Axis (with SN) Dental Analysis UI-NA angle UI-NA distance LI-NB angle LINB distance IMPA LI-FH Pog-NB Distance Skeletal: SNA angle SNA is used to assess the anteroposterior position of maxilla relative to anterior cranial base.

Skeletal: SNB angle SNB is used to assess the anteroposterior position of mandible relative to anterior cranial base.

Skeletal: ANB angle ANB angle indicates magnitude of the discrepancy between the maxilla and mandible. ANB is affected by following factors other than anteroposterior discrepancy of jaws: • Anteroposterior position of Nasion • Vertical position of Nasion • Jaw rotations • Facial height • ANB angle tell us only about “magnitude of the discrepancy between the jaws (maxilla and mandible) ” not the absolute discrepancy. • If treatment is based on obtaining the ideal ANB angle of 2: it may not necessarily obtain the ideal position of either the maxilla or mandible. • Steiner believed the main interest in treatment should be alleviating the magnitude of discrepancy.

Skeletal: occlusal plane angle (SN-Occlusal plane) The mean reading for normal occlusions is 14°. The angle is increased in long face or vertically growing individuals and also skeletal open bite cases. It may be decreased in horizontally growing individuals or cases with a skeletal deep bite. Skeletal: mandibular plane angle (SN-mandibular plane) Excessively high (vertical growers) or low (horizontal growers) mandibular plane angles are suggestive of unfavorable growth patterns and these may complicate treatment results. Dental: UI-NA distance Dental: UI-NA angle • Maxillary Incisors Position: The relative location and axial inclination of the upper incisors are determined by relating the teeth to N-A line. • To precisely determine the relative anteroposterior position of the incisors, it is necessary to measure the distance of the most labial surface of the incisor to the NA line. Dental: UI-NA distance Dental: UI-NA angle • A measurement greater than 4mm show convex facial profile, common in class I bimaxillary protrusion or in class II div 1 relationship. • A measurement less than 4mm show concave facial profile, as in class II div 2 or • Angle greater than 22: may be seen in class II div 1 OR in class III relationship with dental compensation. • Angle less than 22: may be seen in class II div II. Dental: LI-NB distance Dental: LI-NB angle • Angle greater than 25: may be seen in class II div 1. • Angle less than 25: may be seen in class II div II OR class III. Mandibular Incisors Position: The relative location and axial inclination of the lower incisors are determined by relating the teeth to N-B line. • To precisely determine the relative anteroposterior position of the incisors, it is necessary to measure the distance of the most labial surface of the incisor to the N-B line. Dental: interincisal angle A measurement of the degree of procumbency of the incisor teeth, introduced by W. B. Downs as the (posterior) angle formed by the intersection of the long axes of the maxillary and mandibular central incisors. • Highly variable according to the positions of these teeth in different biotypes. • Dolichofacial patients will have vertical upper incisors & high interincisal angles eg. Deep overbite • Brachycephalic patients have more horizontal incisors and lower angles eg. The most biprotrusions are accompanied by a lower IIA.