Gothic Arch Tracing classification and procedure

Tracing

1. Gothic Arch Tracing

2. Contents Introduction History Advantages and Disadvantages Technique Mounting Interpretation Problems associated with recording

3. Introduction

4. Gothic arch tracer :

5. Central bearing point :

6. Central bearing tracing device :

7. History

8. History Phillips 1927

9. Earliest graphic record based on studies on mandibular movement by Balkwill (1866) The first “needle point tracing” was done by Hesse in 1897 Gysi in 1910 have improved and popularized this technique

10. The tracer made by GYSI was an extra oral incisal tracer The tracing plate was coated with wax and attached to mandibular rim A spring-loaded pin or marker was attached to maxillary rim The rims were made of modelling compound to maintain the VDO When a good tracing was recorded, the rims were held at the apex of tracing while notches were scored in the rims for orientation No central bearing point was utilised

11. Clapp in 1914 used gysi tracer directly attached to the impression trays Sears in 1962 used lubricated rims for easier movement. He placed the needle point tracer on the mandibular rim and plate on maxillary rim. He believed this made the angle of the tracing more acute and more easily discernible. He would then cement the rims together for removal.

12. Phillips in 1927 recognized that any lateral movements would cause interference of the rims resulting in a distorted record. He developed a plate for the upper rim and a tripoded ball bearing mounted on a jackscrew for the lower rim “CENTRAL BEARING POINT”

13. Stansbery in 1929 introduced a technique incorporating a curved plate with a 4-inch radius mounted on upper rim. A central bearing device attached to lower rim with a 3-inch radius curve. After the extra oral tracing was made, plaster was injected between the rims to form a biconcave centric registration Hall in 1929 used Stansbery’s method but substituted compound for centric relation record

14. Later graphic recordings methods used central bearing point to produce Gothic arch tracing Hardy and Pleasure described the use of Coble Balancer and Hardy later designed a modified intra oral tracer similar to Cobles Hardy and Porter in 1942 made a depression with round bur at the apex of tracing. The patient would hold the apex in depression while plaster was injected for the centric record

15. Pleasure in 1955 used a plastic disk which was attached to the tracing plate with a hole over the apex of the Gothic arch. The centric relation record could then be made without a change of vertical dimension

16. Various tracing devices were designed by Hights , Phillips, Sears, Terrel, Misserman and others The Sears Recording Trivet had an intra oral central bearing point and two extra oral tracing plates. The maxillary and mandibular rims were locked into Centric relation with two lumps of plaster

17. Silverman in 1957 used intra oral gothic arch tracer to locate the “Biting point” of the patient The patient was told to bite hard on the tracing plate This developed the functional results of the closing muscles which would retrude the mandible The indentation made by the patient would be used for centric record whether or not it corresponds to the Gothic arch Apex

18. The Hight tracer,1986 – It is a four component assembly consisting of an upper bearing plate, lower bearing plate with a central screw, a scriber point to be attached to the upper rim and a tracing platform which extends in front and is attached to the lower rim

19. Chandrasekharan Nair developed “ Chandra tracer ” It is a 2 point assembly 1.Upper bearing plate has a pencil holder 2.Lower bearing plate has a central bearing screw and tracing platform of 35*47mm dimension with a facility of drawing sheet

20. Thank You