Surveying in Removable Prosthodontics

types of surveyors
surveying tools
surveying techniques

1. UNDER GUIDANCE OF : DR. SUPRABHA rathee Dr. avneet kaur SURVEYING PRESENTED BY: SURYANSH SINGH(6088088)

2. CONTENTS TERMINOLOGIES HISTORY OBJECTIVES TYPES OF SURVEYORS PARTS OF SURVEYORS SURVEYING TOOLS SURVEYING LINES HEIGHT OF CONTOUR UNDERCUTS PATHS OF INSERTION USES PROCESS MAINTENANCE CONCLUSION REFERENCES

3. terminologies survey SURVEY-”The procedure of locating or delineating the contour and position of the abutment teeth and associated structures before designing a partial denture.”-GPT 8 surveying SURVEYING-”An analysis and comparison of the prominence of intraoral contours associated with the fabrication of a prosthesis”-GPT 8 surveyor SURVEYOR-”An instrument used in the construction of a removable partial denture to locate and delineate the contours and relative positions of abutment teeth and associated structures.”-GPT 8

4. A line drawn on a tooth or teeth of a cast by means of a surveyor for the purpose of determining the positions of the various parts of a retainer-GPT 8 SURVEY LINES PATH OF INSERTION HEIGHT OF CONTOUR Two or more vertically parallel surfaces of abutment teeth so oriented as to direct the path of placement/removal of a removable partial denture • The direction in which a prosthesis is placed upon and removed from the abutment teeth-GPT 8 A line encircling a tooth designating its greatest circumference at a selected position GUIDING PLANE

5. HISTORY OF SURVEYORS The surveyor is a parallelometer; an instrument used to determine the relative parallelism of surfaces of a teeth or other areas on the cast. DR. A.J. FORTUNATI was the first one to use a surveyor in 1918. In 1923, WEINSTEIN and ROTH produced the first commercially available surveyor, the NEY SURVEYOR . In 1929, NOBLE G WILLS introduced WILLS SURVEYOR . In 1937, NEY introduced the currently used Ney surveyor.

6. Objectives of surveying Determine the most advantageous path of insertion. Locate proximal tooth surfaces - guiding surfaces. Locate and measure undercuts. Identify hard or soft tissue interferences. Determine a path of insertion consistent with esthetic requirements. Delineate the height of contour of the abutment teeth and identify areas of undercut Planning restorative procedures. Record the most ideal cast position for future reference. Plan for the RPD design and the required mouth preparation

7. Types of surveyor NEY’S SURVEYOR- One of the oldest. It has a fixed horizontal arm and vertical arm is retained by friction within a fixed bearing. It also has a fan shaped undercut gauge along with a triangular carbon marker.

8. Wills surveyor It has a rotating horizontal arm (swivel) and a spring loaded surveying arm. Also known as JELENKO surveyor.

9. Williams surveyor It has a Gimbal stage table -adjustable to any desired tilt. Degree of inclination can be recorded for repositioning of cast at any time. Superstructure of this surveyor consists of jointed arm and spring-supported survey rod, all components of which can be locked in fixed position if desired.

10. Electronic surveyor Introduced in 1958 by the US Air Force School of Aviation Medicine. The cast is soaked in phenolphthalein prior to surveying. The surveying tool is charged and a weak current passes through. The region where the cast contacts the surveying tool turns red in color marking the height of contour.

11. STRESS O GRAPH BROKEN ARM CAST SURVEYOR RETENTOSCOPE MICRO SURVEYOR OPTICAL SURVEYOR INTRA ORAL SURVEYOR

12. PARTS OF SURVEYER

13. SURVEYING PLATFORM It is a metal plate parallel to the floor where a cast holder can be placed. It forms the base of the surveyor onto which all the other components are attached and supported.

14. Surveying table It is a stand placed over the surveying platform. The stand has a base and a table to place a cast. The cast can be locked in any position on the table with the help of a locking device. The table is attached to the base with the help of ball and socket joint. Joint facilitate to tilt the table. Surveying table should not be tilted more than 10 degree because with the increase in tilt, the path of insertion will also change.

15. VERTICAL ARM It arises vertically from the surveying platform . It supports the superstructure (horizontal arm and surveying arm).

16. Horizontal arm It extends horizontally from the top of vertical arm. It is designed to support the surveying arm at the free end. It is fixed in the NEY surveyor, whereas it revolves horizontally in JELENKO surveyor.

17. Surveying arm It extends vertically from the free end of the horizontally arm. It is parallel to the vertical arm It can move upward and downward. The lower end of this arm has a mandrel into which, tools used for surveying can be locked in. In Jelenko surveyor , the surveying arm is spring loaded.

18. Surveying tools Analysing Rod Carbon Marker Undercut Gauge Wax Trimmer

19. Analysing rod Used for preliminary survey of the cast. Assessment of degree of undercuts on hard & soft tissues. Assessment of angulation of teeth. In distal extension cases , allows judgement of whether the distal abutment undercuts are sufficient to indicate that a tilt may be beneficial.

20. Carbon marker Basically allows visualization of the analysing rod’s work. Used for drawing survey lines around all teeth involved in clasp design or that have proximal undercuts to be eliminated. To mark the extent of bony/soft tissue undercuts for prosthetic mouth preparation if required. Light pressure without erosion.

21. Undercut gauges Used to measure the location and horizontal depth of undercuts on the analyzed and marked teeth in three dimensions. Stewart – 0.01”,0.015”,0.02” McCracken-0.01”,0.02”,0.03” Same shank , only the size of the tip/ bead varies.

22. Wax trimmers Used to trim off excessive wax while surveying the wax patterns. To prevent over contoured block out of unfavorable undercuts. To demarcate the exact planned clasp arm location to be duplicated. To create a gap/self cleansing area using a 25 trimmer.

23. Survey lines A survey line is defined as “A line drawn on a tooth or teeth of a cast by means of a surveyor for the purpose of determining the positions of the various parts of a clasp or clasps.” – GPT BLATTERFEIN classified survey lines on basis of FAR ZONE & NEAR ZONE into : High survey line Medium survey line Low survey line Diagonal survey line

24. HIGH SURVEY LINE : From occlusal 1/3rd in NZ to occlusal 1/3rd in FZ. Commonly found in inclined teeth and teeth with larger occlusal diameter. Wrought wire clasp is used which is more flexible. MEDIUM SURVEY LINE : From occlusal 1/3rd in NZ to middle 1/3rd in FZ. Either ACKER’S or Roach clasps are used for teeth with medium survey lines. LOW SURVEY LINE : From cervical 1/3rd in NZ to cervical 1/3rd in FZ. Modified T clasp is used for teeth with low survey lines. DIAGONAL SURVEY LINE : From occlusal 1/3rd in NZ to gingival 1/3rd in FZ. Reverse circlet clasp is used.

25. Ney’s classification Class i •Survey line runs diagonally across the tooth surface. •The type of clasp indicated is occlusally approaching cast clasp with terminal third engaging the undercut. Class ii Survey line also runs diagonally across the tooth surface but as a mirror image of Class I line. Here a gingivally approaching clasp arm is suggested. Class iii Survey line is parallel to the occlusal surface and lies just below it.

26. Height of contour First termed by KENNEDY. Represents the greatest bulge of diameter of a crown when viewed from a specific angle or changes as the vertical position of the tooth changes. Tipping or tilting the cast will cause the height of contour to move accordingly. SUPRA BULGE : Surface of the tooth that is occlusal to the height of contour. INFRA BULGE : Surface gingival to the height of contour.

27. UNDERCUTS the portion of the surface of an object that is below the height of contour in relationship to the path of placement -(GPT 8) TYPES OF UNDERCUTS – Tooth Undercuts (Proximal undercuts) Soft Tissues or bony Undercuts(on lingual side of ridge) PROXIMAL UNDERCUTS BONY UNDERCUTS

28. PATH OF INSERTION The specific direction in which a prosthesis is placed on the abutment teeth or dental implant(s). path of withdrawal (reverse of path of insertion) path of placement The RPD path of insertion and withdrawal is the direction in which the prosthesis moves in relation to the support system when it is seated in or removed from the mouth, guided by the contact of its rigid parts with the abutments. (GPT-8)

29. SINGLE PATH OF INSERTION TWO PATHS OF INSERTION MULTIPLE PATHS OF INSERTION

30. Uses of surveyor Surveying the diagnostic and primary cast Tripoding the cast(recording the cast position) Transferring the tripod marks to another cast Contouring wax pattern Contouring crowns and cast restorations Placing internal attachments Placing internal rests. Surveying the master cast Surveying ceramic veneers before final blazing Blockout of master cast

31. PROCESS OF SURVEYING DIAGNOSTIC CAST 1. Preliminary visual assessment of the study cast. 2. Initial survey. 3. Analysis. 4. Final survey

32. Visual assessment Eyeballing Once orientation & tilt is established, allows for a general tangential analysis of undercuts, tooth angulations, etc. Also aids the establishment of relative parallelism of various planar surfaces. Anterior tilt (‘heels up’) Posterior tilt (‘heels down’)

33. Left and Right Tilts

34. Initial survey Cast positioned with the occlusal plane horizontal. The position of the survey lines. ‘Triangle of light’ between the marker and the cervical part of the tooth. Undercut gauges

35. Occlusal plane horizontal Consider: 1. Appearance. 2. Interference. 3. Retention analysis

36. appearance : Undercuts on the mesial aspects of the abutment teeth. Unsightly gap between the denture saddle and the abutment teeth gingival to the contact point.

37. posterior tilt so that the analyzing rod is parallel with the mesiolabial surfaces of abutment teeth. contact of abutment tooth over the whole of the mesiolabial surface and a much better appearance results.

38. Interferences : In MAXILLA – Palatal tori Exostoses and undercuts on maxillary buccal surfaces Facial tipping of posterior teeth Anterior soft tissue undercuts. Palatal tori Exostoses and undercuts on maxillary buccal surfaces

39. IN MANDIBULAR ARCH – Mandibular tori Lingual tipping of posterior teeth Bony prominence often encountered at facial surfaces of mandibular canines and premolars Soft tissue undercuts. Mandibular tori Lingual tipping of posterior teeth Bony prominences on facial surfaces of maxillary canines

40. Retention :

41. Final survey The aims for optimum retention should be to provide: • Resistance along the path of displacement. • Resistance along the path of withdrawal •guide surfaces are used to provide resistance to displacement •retentive portion of the clasp needs only to resist movement along the path of withdrawal • positioned solely with reference to the red survey line.

42. Tripoding the cast Once tilt has been selected for given rpd design, this tilt should be preserved, so that it can be re-established accurately to the surveying table. This is achieved by TRIPODING. METHOD 1 - By placing widely spaced dots on the tissue surface of the cast using the side of the carbon marker, with the vertical arm of the surveyor in a locked position

43. METHOD 2 - Scour 2 sides and the dorsal aspect of the base of the cast with a sharp instrument/ marking pencil held against the surveyor blade. Marks don’t interfere with the design Easy duplication May get smudged upon handling

44. Method 3 A hole about 10 mm in diameter and 10 mm deep is prepared in the lingual land area of the mandibular cast with a large acrylic finishing bur. The pin is locked in the vertical spindle and lowered to the bottom of the hole. The vertical spindle with the pin is then locked in this position and the hole is filled with dental plaster. Once the plaster is set, vertical spindle is released from cemented pin.

45. Method 4 – An instrument reproduces the tilt of a cast on a surveyor using protractor . Flat metal strip 5mm wide and 3cm long, one end of which bend upward at 90˚. Metal rod is attached to the end of the flat part of the strip which serves to fit the instrument to the surveyor. A hole is tapped and threaded in the middle of the bent part of metal strip through which a protractor is screwed The protractor can rotate around the metal rod, acting as a pointer. After determining the path of insertion, the protractor instrument is mounted on the surveyor in place of analyzing rod . 3 divergent points are marked, with readings recorded at each tilt

46. METHOD 5 – Make a hole in the tongue space on mandibular cast 4-6mm in diameter. Hole should create undercut but should not perforate the base of the cast. Following normal surveying procedures, a parallel shanked straight handpiece bur is suspended. With the bur in place, fill the hole with auto polymerizing acrylic resin. For reorientation, reposition the bur in auto polymerizing resin for a parallel tripod record.

47. METHOD 6 – Wax deposited on side of cast at 3 widely separated points Analyzing rod used to create imprints of wax This can be transferred by duplication

48. METHOD 7 – Make a universal tray on a cast after adapting 2mm thickness of baseplate wax over the teeth. Make a platform with a cylinder over the tray and insert analyzing rod into cylinder. Move the tray to and fro vertically during setting of the material to make a smooth vertical perforation in cylinder. Tray loaded with elastic impression material, the cylinder is attached to the rod and locked. After establishing tilt, an impression is made. Reorientation can later be done by placing the impression on cast and the tilt at which the stylus can enter the cylinder locks the prior position.

49. Transferring tripod marks to another cast 3 additional anatomical points marked on diagnostic cast Distal marginal ridge of 1 st premolar Incisal edge of lateral incisor Ling cusp tip of opposite 1 st premolar Same points marked on 2nd cast with analysing rod

50. Contouring the wax pattern Surveyor blade – used as wax carver Proposed path of placement maintained throughout preparation of cast restorations for abutment teeth. Surfaces of restorations that provide reciprocation for clasp arms have to be contoured to permit their location well below occlusal surfaces and on non retentive areas

51. Contouring crown & cast restorations Shape of wax pattern altered during casting & finishing. Working cast with restorations placed at original tilt Cylinder stone. Guide planes refined.

52. Placement of internal rest seats Surveyor used as a drill press Internal rest seats carved in wax pattern, defined in casting or entirely cut in cast restoration It provides positive occlusal support and horizontal stabilization Internal rests may be of Retentive, Non-retentive or Semi-retentive forms

53. Surveying the master cast Surveyed as a new cast Prepared proximal guiding plane surfaces will indicate the correct anteroposterior tilt Any remaining interferences after mouth preparation must be eliminated with block out. Survey lines marked

54. Surveying ceramic veneer crowns Ceramic veneer crowns is used to restore abutment on which an extracoronal rest is placed Surveyor is used to contour wax pattern except labial or buccal surfaces for esthetic reasons Repositioning on surveyor, reshaping with stones may be required before final Glazing of veneer crowns

55. blockout After the establishment of path of insertion and the location of undercut areas on the master cast, the areas that shall be crossed by the rigid parts of the denture must be blocked out. Roach carver or No.7 spatula used to adapt the blocking wax. Four types: o Parallel Blockout o Shaped Blockout/Ledge Blockout o Arbitrary Blockout o Relief

56. Parallel blockout Performed: o On interproximal surfaces to be used as guiding planes(0/2/6˚ taper) o Beneath all minor connectors o On tissue undercuts to be crossed by rigid connectors o Beneath bar clasp arms to gingival crevices Materials Used: o Hard baseplate wax o Hard inlay wax o Oil based modelling clay Thickness-Only undercut remaining gingival to contact of surveyor blade with tooth surface

57. Shaped/ledge blockout Performed: o On buccal & lingual surfaces to locate plastic or wax patterns for clasp arms Material: o Hard Baseplate Wax Thickness: Ledges for location of reciprocal clasp arms to follow height or convexity so that they may be placed as cervical as possible without becoming retentive

58. Arbitrary blockout Performed: o On all gingival crevices o On gross tissue undercuts below areas involved in framework design o On tissue undercuts distal to cast framework o Labial & buccal tooth undercuts not involved in denture design Material: o Oil Based Modelling Clay o Hard Baseplate Wax Thickness : Enough to just eliminate gingival crevice, levelled arbitrarily with a wax spatula

59. relief Provided: o Beneath lingual bar connectors or the bar portion of linguoplates o On areas in which the major connector will contact thin tissue o Beneath framework extensions onto ridge areas for attachment of resin bases Material: o Adhesive wax o Hard Baseplate Wax Thickness: o 32 gauge wax(universally) o 20 gauge wax for resin base attachment relief

60. Maintenance of surveyor Wipe the base of surveying table and surveying platform with alcohol or acetone soaked gauge pad. Acrylic resin powder can be sprayed for smooth gliding. Machine oil should be applied to vertical arm before and after use, each time.

61. conclusion Preservation of abutment teeth and supporting structures of the oral cavity depends on accurate and knowledgeable survey and design. To plan, survey, and design a removable partial denture which will provide proper retention, support, stabilization, and esthetics, is essential for the success of the removable partial denture.

62. references Stewart’s clinical REMOVABLE PARTIAL PROSTHODONTICS – 4 th Edition and 2nd edition McCracken’s Removable partial prosthodontics – 11th Edition An Atlas Of Removable Partial Denture Design – Stratton www.google.com www.Wikipedia.com

63. THANKYOU