Dental Surveyor

‘A paralleling instrument used in construction of a prosthesis to locate and delineate the contours and relative position and abutment teeth and associated structures’

1. SURVEYING Presented by:- Dr Arun Kumar Tiwari

2. Introduction One piece of equipment without which the modern clinical practice of RPD would not be possible is the Surveyor . The turning point in the change of partial denture construction from guesswork based on clinical experience to scientifically based procedure was the appearance of the dental surveyor in 1918 .

3. Introduction In 1954, Applegate commented that the intelligent use of the dental surveyor is the best way to prevent the occurrence of countless problems frequently related to oral rehabilitation with RPDs.

4. SURVEYOR Surveyor is a parallelometer, an instrument used for determining the relative parallelism of two or more surfaces of the teeth or other areas on a cast of the jaws. (Stewart) ‘A paralleling instrument used in construction of a prosthesis to locate and delineate the contours and relative position and abutment teeth and associated structures’ (GPT-8)

5. SURVEY- ‘The procedure of locating and delineating the contour and position of the abutment teeth and associated structures before designing a removable partial denture’. ( GPT-8) SURVEYING – ‘An analysis and comparison of the prominence of intraoral contours associated with the fabrication of a prosthesis’ (GPT-8)

6. DEVELOPMENT OF DENTAL SURVEYOR Journal of Prosthodontics, Vol 11, No 1 (March), 2002: pp 11-18 Journal of Prosthodontics, Vol 11, No 2 ( June), 2002: pp 122-130

7. Eyeballing …. Before the investigation of dental surveyor, dentist evaluated axial contours and undercut of teeth by visual survey of dental cast. Technique developed by W.M. Randall in 1920. Cast stabilized by wax or compound.

8. The cast is then eyeballed-viewing the cast with one eye closed. One sharp pencil is hold with hand perpendicular to occlusal plane, the practitioner would pass a pencil lead over the axial surfaces of the teeth to develop a survey line at the greatest diameter of each tooth. Eyeballing…

9. 1918- Dr. A J Fortunati is thought to be the first person to employ a mechanical device to determine the relative parallelism of tooth surface. At a clinic in Boston he demonstrated a method of charting correct clasp placement by using a parallelometer with graphite rod. Dr. K ennedy was later credited with coining the term “height of contour”.

10. Parallelometer (Chayes 1920) Paralleling devices were in use long before the development of dental surveyor. Used to assure proper alignment of precision attachment and also used to identify nonparallel and/or undercut surfaces of prepared teeth .

11. THE FIRST DENTAL SURVEYOR Developed by NEY in 1923 featured a convenient palm rest on the top of the vertical arm. Designed by Weinstein and Roth THE ORIGINAL NEY SURVEYOR

12. Currently used NEY SURVEYOR designed & developed in 1937 .

13. ELECTRONIC DENTAL SURVEYOR The heated waxing instrument could be used to shape and trim the blockout wax.

14. The austenal microanalyser measures undercut electronically, and a dial indicator shows the desired amount of undercut, and a flashing light signals when the exact undercut is reached

15. MICROSURVEYOR collapses for handy storage in a case that could fit into a lab coat pocket

16. DENTAL SURVEYOR WITH BUILT IN MILLING MACHINE Dental surveyors have been developed to function as milling machines or drill presses . Developed for precision attachment applications, these instruments ensure the parallelism of guiding planes milled into castings.

17. Ney Surveyor Jelenko Surveyor Williams Surveyor The Retentoscope The Ticonium surveyor The Micro-Analyzer TYPES OF DENTAL SURVEYOR

18. Ney Surveyor Jelenko Surveyor Williams Surveyor The Retentoscope The Ticonium surveyor The Micro-Analyzer TYPES OF DENTAL SURVEYOR

19. Ney Surveyor Jelenko Surveyor Williams Surveyor The Retentoscope The Ticonium surveyor The Micro-Analyzer TYPES OF DENTAL SURVEYOR

20. Ney Surveyor Jelenko Surveyor Williams Surveyor The Retentoscope The Ticonium surveyor The Micro-Analyzer TYPES OF DENTAL SURVEYOR

21. Ney Surveyor Jelenko Surveyor Williams Surveyor The Retentoscope The Ticonium surveyor The Micro-Analyzer TYPES OF DENTAL SURVEYOR

22. PRINCIPLE Of WORKING If a vertical plane is brought into contact with a curved surface, it will touch at the greatest bulge on the convexity and nowhere else.

23. PARTS OF DENTAL SURVEYOR Vertical arm Horizontal arm Surveying arm Surveying table Surveying platform Mandrel with attached analyzing rod

24. PARTS OF SURVEYOR 1. Platform on which the cast holder is moved 2. Vertical arm that supports superstructure 3. Horizontal arm from which surveying tool suspends . 2 1 3

25. PARTS OF A SURVEYOR 4. Surveying table or cast holder to which the cast is attached. 5. Base on which the table swivels 6. Analyzing rod or Paralleling tool or guideline marker 4 5 6

26. 7. A surveying arm that drops vertically from the horizontal arm . The surveying arm is capable of movement in vertical direction . 8.Mandrel for holding special tools as Carbon marker, analyzing rod, wax trimmer and undercut gauge 8. 7. PARTS OF A SURVEYOR

27. Attachments of surveyor: Analysing rod Graphite marker Undercut gauge Trimming knife

28. Analyzing rod:- This metal rod is placed against the teeth and the ridge during the initial analysis of the cast to identify undercut areas and areas of parallelism without marking the cast. Analyzing Rod

29. The graphite marker is moved along the teeth and the alveolar ridge to identify and mark the position of maximum convexity. (SURVEY LINE) Graphite(Carbon) marker

30. They are used to determine the amount and location of retentive undercut on the surface of an abutment tooth and are available in sizes ; 0.010inch, .015 inch and 0.020 inch ( Mccracken - .010inch, .020 inch, .030inch) Undercut gauge

31. Chisel (Wax Trimmer) Trimming Knife: Wax is added to block the unwanted undercut and the wax trimmer is used to remove the excess wax.

32. USES OF SURVEYOR Surveying the diagnostic cast Contouring wax patterns Placement of internal rest seat Surveying the master cast Recontouring abutment teeth on the diagnostic cast Aids in placing guide plane Measuring depth of undercut on abutment tooth

33. Survey lines “A line drawn on a tooth or teeth of a cast by means of a surveyor for the purpose of determining the position of various parts of a clasp or clasps”- GPT 8 Survey line are nothing but height of contour of a teeth marked by carbon marker.

34. Survey line divides tooth in two parts : SUPRABULGE area : Occlusal to survey line. Its provide support. INFRABULGE area : Apical to survey line . It is for retention

35. CLASSIFICATION OF SURVEY LINE: BLATTER FEIN SYSTEM: He introduced the terms Near Zones and Far Zone. Near Zone - is the half which lies nearer to the saddle or edentulous area. Far Zone - is the half which is away from the saddle. According to Blatterfein , survey lines are The high survey line. The medium survey line. The low survey line. The diagonal survey line.

36. High Survey Line This survey line appears near to the occlusal than the gingival of the tooth in both near and far zones. found on the lingual surfaces of lower teeth and on buccal surface and uppers.

37. It passes from the middle third of the tooth in the near zone to the gingival third of the tooth in the far zone. Medium Survey Line

38. Low Survey Line Very low on the buccal or lingual aspect of a tooth. Marked inclination of the tooth, also found on the conically shaped tooth.

39. Diagonal Survey Line These types of survey lines are present near the occlusal surfaces of near zone to cervical surface of far zone. Such lines are most commonly found on the buccal surface of canines and premolars

40. COLOR CODING

41. A color coding system for the various parts of the removable partial denture as well as for other items of information that should be included on the diagnostic casts helps prevent confusion on the part of a dental laboratory technician or any one trying to understand the design being proposed.

42. Brown crayon pencil  out line the metallic portion. Blue crayon pencil out line the acrylic portion of the denture base. Red crayon pencil to indicate areas on the teeth that will be prepared. Solid red rests and rest seats. Black pencil and carbon marker used to denote the survey lines

43. SURVEYING-TILTING Initially when the cast is placed on the table the occlusal surface is made parallel to the platform. However the final tilt of the cast at which the surveying is done is decided on the basis of the path of insertion to be selected. To achieve that the table can be tilted in different direction: Anterior tilt. Posterior tilt Lateral Tilt.

44. Anterior tilt: - the anterior of the cast is lowered Posterior tilt:- the posterior of the cast is lowered. Right tilt:- the right side of cast is lowered, as viewed from the rear. Left tilt:- the left side of cast is lowered . Any combination of tilt may be used, but excessive tilt must be avoided.

45. Use right or left tilt for casts which have one abutment tooth abnormally aligned. For example, if a lower left molar is tipped badly to the lingual, the path of insertion must be from right to left to favor the tipped tooth. SURVEYING-TILTING

46. The tilt may be changed to accomplish specific purpose, but exaggerated tilt (more than 10 degrees from the horizontal )must be avoided.

47. Tripoding … After the final tilt of the cast has been selected, it must be recorded so that the cast may later be repositioned precisely known as tripoding . Method- Place three cross marks on the tissue portion of the cast ,lingual to the remaining teeth at widely separated points while the cast and vertical arm of the surveyor are held at fixed positions. This will established 3 point on the same horizontal plane.

48. Transferring tripod marks to another cast Three points selected from the diagnostic cast must be identified and with the analyzing rod held at a fixed vertical position, the cast is tilted in various ways until the tip of analyzing rod contacts the points on the same horizontal plane.-the tilt of both the cast is now exactly the same. Reference points are: Distal marginal ridge of the first premolar, the incisal edge of the lateral incisor, and the lingual cusp tip of the left first premolar.

49. Surveying the Master Cast The following factors are checked during survey of the master cast : Parallelism of the guiding plane Depth of undercuts and retention Height of contour Interference Aesthetics

50. Retentive undercuts Retentive areas must exist for a given path of placement & must be contacted by retentive arms If retentive undercut are not present they must be created-enamel surface can be contoured in limited.

51. Ideally, proposed abutment teeth should have 0.010 inch of undercut at the most desired location - Distobuccal or mesiobuccal line angle and in gingival third of the clinical crown of the teeth. Normally tilt is changed to lower the height of contour of an abutment teeth so that a clasp be positioned no more occlusal than the junction of gingival and middle third of the teeth-improves esthetic and lowering rotational forces the clasp transmit the teeth.

52. INTERFERENCE The prosthesis must be placed & removed without interference with tooth & soft tissue structure. Interference may be eliminated during mouth preparation by surgery, extraction, modifying interfering tooth surfaces, or altering tooth contours with restorations

53. INTERFERENCE Interferences in the mandible Lingual tori Bony exostoses Lingually inclined teeth. Interference in the maxilla : Torus platinus Bony exostoses Buccal tipped teeth.

54. AESTHETICS Clasp arms must be concealed. Positioning the clasp arm at a lower level will help to conceal the clasp arm. A balance should be obtained between aesthetics and function. The artificial anterior teeth should be placed in the same position as the natural teeth.

55. Cases with mesially tilted abutments on either side of the edentulous space will have large unaesthetic undercuts with accumulation of plaque and debris. This can be eliminated either by tilting the cast posteriorly or altering the path of insertion or by selectively grinding. AESTHETICS

56. GUIDING PLANES Two or more parallel axial surfaces on abutment teeth can be used to limit the path of insertion and improve the stability of a removable prosthesis. Need not to be more than 2-3mm in occluogingival height. Surveyor is used to locate existing or potential surface of teeth that can be converted to guiding planes by selective grinding.

57. GUIDING PLANES Functions of a guiding plane : Makes insertion and removal of the prosthesis easier. It minimizes the wedging stresses on the abutments. Aids to stabilize the prosthesis against horizontal stresses Aids to stabilize individual teeth.

58. RECENT ADVANCES 

59. Electronic surveying

60. A 3-dimensional computer model of a conventional cast from a patient is obtained using an optical surface capture device (a scanner) The shape of number of components of a removable partial denture framework was modeled on the 3-dimensional scan electronically, using computer- aided design software. A physical plastic shape of the components was produced using a Rapid Prototyping machine and used as a pattern used as a pattern.

61. Use of cad-cam technology to fabricate a removable partial denture framework removable partial denture framework  This is the first patient fitted cobalt-chromium fitted cobalt-chromium RPD framework produced by cad-cam and rapid prototype technology.

62. Conclusion The many advantages gained by the intelligent use of the dental surveying instrument have been discussed. The application of the surveyor is not limited to removable partial dentures but is equally effective as a diagnostic and treatment planning aid in fixed partial dentures, complete dentures.

63. References REMOVABLE PARTIAL DENTURE by McCraken A CLINICAL GUIDE TO REMOVABLE PARTIAL DENTURE by J.C. DAVENPORT et al CLINICAL REMOVABLE PARTIAL PROSTHODONTICS by Stewart

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