Magnification in endodontics

Description of Dental Loupes and the Dental Operating Microscope.

1. Magnification in Dentistry

2. ONLY THING IN LIFE WHICH IS CONSTANT IS CHANGE

3. Technology constantly forces us to relook at are processes and improve

4. It may seem surprising that the microscope is not a high-tech instrument. It has been used in the medical field for over 50 years. Zeiss Company states that it first introduced to Otolaryngology in 1950s to Neurosurgery in 1960s to Endodontics in 1990s Dentistry, therefore, is about 40 years behind medicine in this respect.

5. In dentistry, Endodontists were first to introduce it Gary Carr is regarded as the father of microscopic endodontics

6. Why is Magnification important??

7. Resolution The ability to differentiate between two closely positioned bright objects.

8. The resolving power of the unaided human eye is only .2 mm. In other words, most people who view two points closer than .2 mm will see only one point. The film thickness of most crown and bridge cements is 25 microns (.025 mm), or well beyond the resolving power of the naked eye. Operating microscope can raise the resolving limit from 0.2mm to 0.006 mm (6 microns), a dramatic improvement. WHAT IS THE LIMITS OF HUMAN VISION….??

9. How do we improve our ability to resolve small objects Use of magnification!!! Use of light!!!

10. Lets start with few basic concepts of optical properties Magnification Magnification of an image is a relative value and has to do with the size of an image as projected onto the retina of the eye The magnification of an image is increased by simply decreasing the distance between the eye and the object in question.

11. Working distance The distance at which the optics of a Loupes or Microscope are sharply focussed. Distance should be sufficient to place the hands and the instruments comfortably between the Loupe or microscope and the operating area.

12. Depth-of-Field / Depth-of-Focus The range over which the image remains sharply focussed. These terms relate to the area in front of, and behind, the point of perfect optical focus, where sharp focus is maintained.

13. Field of view The area that can be seen under magnification at normal working distance

14. Tools for magnification in dentistry Magnifying loupes Operating microscopes

15. LOUPES Loupes are classified by the optical method by which they produce magnification. There are 3 types of binocular magnifying loupes: Diopter , flat-plane, single lens loupe, Surgical telescope with a Galilean system configuration (2-lens system) Surgical telescope with a Keplerian system configuration (prism roof design that folds the path of light).

16. The diopter system relies on a simple magnifying lens. The degree of magnification is usually measured in diopters. One diopter (D) means that a ray of light that would be focused at infinity now would be focused at 1 meter (100 cm or 40 inches). A lens with 2 D designation would focus to 50 cm (19 inches); a 5 D lens would focus to 20 cm (8 inches). Diopter(D) is not equal to magnification(X). Diopter

17. The only advantage of the diopter system is that it is the most inexpensive system. But the plastic lenses that it uses are not always optically correct. Furthermore, the increased image size depends on being closer to the viewed object, which can compromise posture and create stresses and abnormalities in the musculoskeletal system

18. Galilean system The Galilean system provides a magnification range from 2x to 4.5x and is a small, light, and compact system

19. Keplarian system These are prism loupes use refractive prisms and are actually telescopes with complicated light paths, which provide higher magnifications.

20. Both systems produce Superior magnification. C orrect spherical and chromatic aberrations. Excellent depth of field. Capable of increased focal length (30–45 cm), thereby reducing eyestrain and head and neck fatigue.

21. TYPES OF LOUPES TTL-Through the lens Flip up Loupes Head Mounted loupes

22. Loupes with lighting

23. Importance of choosing the right light Light intensity LED LIGHT WITH INTENSITY FROM 40,000 LUX ONWARDS

24. Importance of choosing the right light Color rendering Pure white LED’s provide ‘true color’. Unfortunately, many LED headlights on the market display a blue beam, rather than a pure white beam. This blue beam will result in severe color distortion and is most commonly found in very inexpensive LED lights. 

25. Importance of choosing the right light Homogenity

26. Limited magnification Illumination is not as high as a microscope. Loupes with higher magnification are uncomfortable on the nose or head due to their large size and increased weight. Imaging and documentation not possible. Disadvantages

27. Microscopes The operative microscopes provides greater magnification and illumination & functions as an extension of loupes

28. Parts of a operative microscope The operating microscope consists of three primary components — The supporting structure, The body of the microscope, and The light source.

29. The Supporting Structure It is essential that the microscope be stable while in operation, yet remain manoeuvrable with ease and exceptional precision, particularly when used at high power. The supporting structure can be mounted on the floor, ceiling, or wall. As the distance between the fixation point and the body of the microscope is decreased, the stability of the setup is increased.

30. The Supporting Structure WALL MOUNTED/ HIGH WALL MOUNTED

31. The Supporting Structure FLOOR MOUNTED

32. The Supporting Structure CEILING MOUNTED

33. The Supporting Structure TABLE MOUNTED

34. The Supporting Structure HEAD MOUNTED MICROSCOPE

35. Eye piece Binoculars Magnification changers Objective lens Light housing Accessories Body of the Microscope

36. Eyepieces

37. Binoculars Function to hold the eyepieces IPD set by adjusting the distance between two binocular tubes. Once diopter setting and IPD are set, they are not to be changed until the microscope is used by a surgeon of different optical requirements Comes in different focal lengths Available with straight, inclined or inclinable tubes

38. Magnification Changers Available as either three/five/six step manual changers or power zoom changer Series of lenses that move back and forth on a focusing ring to give a wide range of magnification Controlled by either a foot control or a manual override. Foot control allows the clinician to adjust magnification and focus without taking the hands or eye away from the surgical field.

39. Objective Lens Nearest to the surgical field. Focal length of it determines distance between the lens and the surgical field Available with focal length ranging from 100 to 400mm A 200-250mm objective lens is recommended. Reason : There is enough room to place surgical instruments and still be close to the patient.

40. Magnification determined by : Power of the eyepiece The focal length of the binoculars The magnification changer factor The focal length of the objective lens

41. LIGHT HOUSE (Illumination) Microscope illumination can be of two varieties. Originally, microscopes had only externally mounted independent illuminators transmitting light but creating some shadows and unable to get down deep into cavities.

42. Co axial illumination This means that the light from the illuminator bulb is re-routed to a point very near the viewing axis of the microscope and is projected down through the same objective lens used for viewing No shadow. Under the microscope, a specific amount of light will be projected and any change made in microscope magnification will have no effect on the amount of light being projected from the microscope.

43. However, Changes made in the magnification of the microscope do, increase or decrease the amount of light which will be projected back through the microscope and onto the retina of the eye of the viewer.

44. Therefore an increase in magnification is accompanied by a decrease in illumination Several manufacturers, however, have gone to great efforts to minimize this by using ultra-wide, multi-coated optics. Therefore, this effect will be difficult to notice, if not impossible.

45. Recommended lighting The light source can be powered by a Halogen light bulb or by a Xenon light . Some halogen lights provide an artificial yellow light, which is not ideal for documentation, so any product must be carefully selected. LED’S are the light sources of choice now.

46. ACCESSORIES Beam Splitter Filters Eyepiece With Reticle Field Monitors/ LCD screens Assistant Scope Cine Or Photographic Adapters

47. Beam Splitter : Function is to supply light to accessories such as a camera or an auxiliary observation tube. 50:50 beam splitter along with other configuration available

48. Photo adapters attach camera & video camera to beam splitter Photo or cine adapters also provide the necessary focal length so that the camera records an image with the same magnification and field of view as seen by the operator

49. Filters Reason for filters….?? Green for surgical procedures - it removes the confounding red reflections of the blood Orange filter – prevents premature setting of composite resin.

50. Eyepiece with reticle field An eyepiece reticle is a glass disc with a pattern on it that fits at the optical plane inside a microscope eyepiece. An eyepiece with a reticle field can be substituted for a conventional eyepiece and can prove an invaluable aid for alignment during videotaping and 35 mm photography.

51. LCD screen

52. Assistant scope/ C o-observation tube Useful to assistant. Also better to assistant than looking at monitor. Can be monocular or binocular.

53. COOBSERVATION TUBE PHOTOGRAPHIC ADAPTER CINE ADAPTER PISTOL GRIPS EYEPIECE WITH A RETICULE FIELD

54. Pre requisites For The Use of The Microscope In Non-Surgical Endodontics Rubber Dam Placement Indirect View and Patient head Position Mouth Mirror Placement Some Key Instruments

55. Rubber dam placement While using operating microscope rubber dam becomes a necessity. Most of the procedure is performed using a mirror and indirect vision If rubber dam is not used then t he mirror would fog immediately from the exhalation of the patient. Thus, the powerful microscope magnification and illumination would be rendered totally useless

56. Indirect view and patient head position It is nearly impossible to view the pulp chamber directly under the microscope Instead, the view seen through the microscope lens is a view reflected by way of a mirror.

57. Some key instruments The ability to locate hidden canals is the most important and significant benefit gained from using the microscope. To do this effectively and efficiently, clinicians must use specially designed microinstruments. There is only a tiny space between the mirror and the tooth for a finger with a file to move around files specially designed by Maileffer, called microopeners , have a handle with different sized tips and can be extremely useful.

58. ULTRASONIC TIPS CPR TIPS BUC TIPS STARTEX TIPS

59. MICROMIRRORS

60. In chronological order, the preparation of the microscope involves the following maneuvers: 1 Operator positioning 2 Rough positioning of the patient 3 Positioning of the microscope and focusing 4 Adjustment of the interpupillary distance 5 Fine positioning of the patient 6 Parfocal adjustment 7 Fine focus adjustment 8 Assistant scope adjustment

61. Most appropriate operating position is a combination of Patient Head Position Dental Chair Position Microscope Position Surgeon Position Assistant Position Assistant observation Devices

62. Patient Head Position Ensuring Patient comfort during surgery utmost important No straining/ torquing of head & neck muscles Occlusal plane be Parallel to floor for mandibular surgery, perpendicular for maxillary surgery Head be comfortably centered or slightly turned

63. Microscope Position Most endodontists prefer Ceiling mounted operating microscope Suspension arms supports and position the microscope in horizontal & vertical dimensions An addition of a Rotational attachment (Mora) or a extender makes the positioning of the Microscope easier.

64. Selection of Binocular critical Inclinable binocular are the best one. Inclinable tube provide the operator with additional postural comfort during long procedures but they are comparitively expensive.

65. Should Use an Adjustable stool Thighs parallel to floor Arms relaxed, and placed comfortably at side Surgeon Position

66. A well designed microsurgery may need three assistants FIRST ASSISTANT : responsible for suctioning, usually seated SECOND ASSISTANT : Passes instruments, positioned next to the surgeon’s dominant site if a front delivery system is used, positioned across the surgeon THIRD ASSISTANT : Incharge of the video and photographic functions Assistant position

67. The Laws of Ergonomics An understanding of efficient work flow using a microscope entails a knowledge of the basics of ergonomic motion. Ergonomic motion is divided up into five(5) classes of motion:

68. That all instruments and equipment needed for a procedure are within reach of either the clinician or the assistant , requiring no more than a class IV motion, And that most endodontic procedures are performed with class I or class II motions only Therefore, the circle of influence design principle places the OM at the center and all other things required within the circles Circle of influence

69. Circle of influence

70. Some interesting cases

71. Retrieval of broken files

72. CBCT assessment of thermoplasticized obturation of a C-shaped canal

73. Case report Female patient, aged 40 years, reported to the department of Conservative Dentistry and Endodontics with pain in the lower left back tooth region. On examination,deep class V caries was observed with respect to 37.IOPA reveals radiolucency involving pulp.Pulp vitality testing revealed no response to cold test,heat test and a delayed response to EPT.CBCT revealed a C-shaped canal configuration which had a distobuccal apical exit. Access opening was done wrt 37,working length was determined as 15 mm.Apical instrumentation was done using K-files upto size 60 K file.Circumferential filing was done.3 rounds of Ca(OH)2 dressing was placed.Obturation was done using Continous wave obturation technique and System B-Elements system .Amalgam core build up was done

74. CORONAL THIRD-7.5 MM FROM APEX

75. MIDDLE THIRD-5MM FROM APEX

76. APICAL THIRD-2 MM FROM APEX

77. MB2 DETECTION

78. PLAIN EYESIGHT 2.5X MAGNIFICATION 12.8X MAGNIFICATION

79. Management of a Maxillary Molar with 5 canals

80. Thank you