Ricketts analysis

Orthodontics- Cephalometric Analysis for Dental Students(In detail describing Ricketts Analysis)

1. R icketts BioProgressive Analysis

2. Skeletal Land Marks A Point ANS BA(Basion) PT Point ( The intersection of the inferior border of the foramen rotundum with the posterior wall of the pterygomaxillary fissure ) CC(Centre of Cranium- Cephalometric landmark formed by the intersection of the two lines BA-NA and PT-GN ) CF(Centre of Face- intersection of the line connecting Porion and orbitale and perpendicular through Pt ) DC ( Centre of neck of Condyle coinciding with Basion Nasion Plane ) GO ( Point formed by intersection of Ramus And Mandibular Plane ) PM Point ( A point selected at the anterior border of the symphysis between point B and pogonion where the curvature changes from concave to convex ) PO Point(Pogonion) Xi Point

3. Dental Landmarks A 6 (Upper molar). A point on the occlusal plane located perpendicular to the distal surface of the crown of the upper first molar. B 6 (Lower molar). A point on the occlusal plane located perpendicular to the distal surface of the crown of the lower first molar. TI point. The point of intersection of the occlusal and the facial planes.

4. Landmarks

5. CC(Centre of Cranium) Cephalometric landmark formed by the intersection of the two lines BA-NA and PT-GN

6. Deriving Xi Point ( A Point located at the Geometric Centre of the Ramus) R1. Mandible . The deepest point on the curve of the anterior border of the ramus, one-half the distance between the inferior and superior curves. R2. Mandible . A point located on the posterior border of the ramus of the mandible. R3. Mandible . A point located at the centre and most inferior aspect of the sigmoid notch of the ramus of the Mandible. R4. Mandible . A point on the border of the mandible directly inferior to the centre of the sigmoid notch of the ramus. Xi Point is located in the centre of the rectangle at the intersection of diagonals.

7. Basic Reference Planes Horizontal reference plane Frankfort horizontal (FH) plane is constructed by connecting the porion and the orbitale. Vertical reference plane Pterygoid vertical (PTV) is constructed by drawing a line perpendicular to the Frankfort plane at the posterior margin of the pterygopalatine fossa.The intersection of FH and PTV has been found to be stable, i.e. the change in the location of this point as a result of patient growth is minimal. Therefore, serial cephalometric tracings of a patient superimposed at this point are recommended. Facial Axis It is a line from PT point through cephalometric Gnathion which normally interacts BA-NA at Right Angles. Cranial Base Plane It is a line formed by connecting BA-NA,in normal Caucasians it forms 30 ° with FH plane. Occlusal plane It is a line bisecting the overbite of the molars and passing through the overbite of the first bicuspids. The occlusal plane is nearly parallel to the Frankfort horizontal and palatal plane. Maxillomandibular relationship Horizontally, the maxilla and mandible of the normal face are in alignment, both falling along the facial plane. Vertically,the relation of the maxilla to the mandible is described by the lower facial height and the intersection of two planes,ANS-Xi and Xi-PM. The norm for this measurement is 45° The maxillary first molar normally is 21 mm anterior to the pterygoid vertical. The relationship of the maxillary to the mandibular first molars is such that the maxillary molar is 3mm distal to the mandibular molar.

8. Reference Planes

9. Eleven factor summary analysis Provides an overview of the patient's craniofacial and dental growth direction. Facial axis angle . This angle is formed by the intersection of BA-NA line and the facial axis. The angle describes the direction of growth of mandible at chin. A larger angle indicates horizontal direction of mandibular growth while a smaller angle is suggestive of more vertical growth. Facial axis angle remains stable in a normally growing child or reduce a little. Facial depth angle. This angle is formed by the intersection of the facial plane and the Frankfort horizontal plane. This angle gives the clinician an indication mandible (pogonion) in sagittal direction. This facial depth angle increases 1° every 3 years as the mandible grows forward and downward. In adulthood, the mean measurement is 90°. Mandibular plane angle. The mandibular plane angle is formed by the intersection of mandibular plane and the Frankfort horizontal plane. High mandibular plane angle indicates Leptoprosopic and low angle Euryprosopic. Lower facial height. This is the angle formed by the intersection of a line from anterior nasal spine (ANS) to Xi-point and the corpus axis (Xi-PM). A larger angle indicates a divergence of mandible and maxilla or vertical growth trend. Lower facial height angle does not usually change significantly with age. However,this angle would be affected by treatment mechanics,i.e. it may open or close the bite. Low values of angle are suggestive of horizontal facial pattern. Mandibular arc. The mandibular arc is the angle formed by the intersection of the condylar axis (DC-Xi) and the distal extrapolation of the corpus axis. It describes the configuration of the mandible whereby a large angle is indicative of a 'strong' and 'square mandible; a small angle represents a lower jaw with a short ramus and vertical growth pattern. Smaller angles suggest a short romus and vertical growth trend. The norm for a 9-year-old child is 26° + or - 4º. It decreases approximately 0.5° per year with growth. Measurements to locate the chin in space

10. 6. Convexity of point A . Facial convexity is the distance in millimeters from A point to the facial plane, when measured perpendicular to that plane.The normal growth trend shows more anterior growth of the mandible than the maxilla.Thereby a decrease in its measurement with age.At maturity, the norm is 9 mm, indicating that A point lies along the facial plane a high convexity indicates a Class II skeletal pattern; negative convexity, a skeletal Class III. Measurements to determine convexity

11. Measurements to locate denture in face 7. Lower incisor protrusion . This linear measurement relates the position of the tip of the lower central incisor to the maxillomandibular relationship. The plane used to describe this relationship intersects both A point and pogonion (A-PO). The distance from the tip of the incisor is measured perpendicular to this plane. The position of the lower incisor has been associated both with aesthetics and stability as suggested by Tweed. Labial or lingual movement of lower incisors affects archlength. 8. Mandibular incisor inclination . The angular measurement formed by the intersection of the long axis of the lower central incisor and the A-PO plane is called the lower incisor inclination. The measurement also relates the lower incisor to the maxillomandibular relationship. 9. Upper molar position . Upper molar position is the linear distance between the most distal point of the maxillary first permanent molar, and the pterygoid vertical (PTV) measured parallel to the occlusal plane.This measurement indicates mesial or distal position of the upper denture. It is also indicative of whether or not the upper molar can be moved distally without impacting the maxillary second and third molars. Norm is the patient's age (in years) plus 3 mm. At least 21 mm of maxilla (+/- 3 mm) is generally needed in later years for proper eruption of the second and third molars. 10. Interincisal angle. The angle depicts cumulative proclination of the upper and lower incisors. It does not quantify the proclination of maxillary/mandibular tooth.

12. Measurements to determine the profile 11. Lower lip to E-plane. The lower lip protrusion is evaluated by measuring the lower lip from an aesthetic line constructed by joining the tip of the nose and the tip of the chin. 12. Maxillary depth. This angle is formed by intersection of FHP to a line from Nasion to A point. The maxillary depth angle relates horizontal position of maxilla at point A to cranium (NA).

13. 11 Parameters of Ricketts Analysis

14. Summary Ricketts cephalometric analysis essentially tries to orient face and mandible to the cranium. His analysis was fundamental to this treatment approach whereby he gave great emphasis to the growth and facial growth pattern. The ultimate objective was to integrate growth to work out best possible treatment plan.