Magnification assisted dentistry

Magnification in Dentistry, use of loupes and microscopes, principles of ergonomics.

1. Magnification Assisted Dentistry ‘You can only treat what you can see’ Dr . Ashok Ayer Department of Conservative Dentistry & Endodontics College of Dental Surgery, BPKIHS, Dharan , Nepal

2. Contents: Introduction: A brief history of magnification Evolution of magnification and illumination in medicine Evolution of magnification and illumination in dentistry Loupes Endoscopy Dental Operating Microscope Magnification Illumination Accessories Advantages Disadvantages Misconceptions about surgical microscopes Use of Dental Operating Microscope in endodontic therapy Conclusion References

3. Introduction: Traditional endodontics has been based on feel not sight. Together with radiographs and electronic apex locators this blind approach has produced surprising success. There is, however, a significant failure rate, especially in long-term. Magnification helps the user not only to see more, but to see well.

4. High levels of magnification increase the aggregate amount of visual information available to endodontists for diagnosing and treating dental pathology. Improved ergonomics and zero defect endodontics.

5. Clinically, most dental practitioners will not be able to see an open margin smaller than 0.2 mm. The film thickness of most crown and bridge cements is 25 µm (0.025 mm), well beyond the resolving power of the naked eye. Human mouth is a small space to operate in, especially considering the size of the available instruments ( eg , burs, handpieces ) and the comparatively large size of the operator’s hands. Gary B. Carr, Carlos A.F. Murgel . The Use of the Operating Microscope in Endodontics. Dent Clin N Am 54 (2010) 191–214

6. A dollar bill without magnification. Note that the lines that make George Washington’s face cannot be seen in detail. Gary B. Carr, Carlos A.F. Murgel . The Use of the Operating Microscope in Endodontics. Dent Clin N Am 54 (2010) 191–214

7. Different magnifications of a dollar bill as seen through an OM. (A) Magnification 3. (B) Magnification 5. (C) Magnification 8. Gary B. Carr, Carlos A.F. Murgel . The Use of the Operating Microscope in Endodontics. Dent Clin N Am 54 (2010) 191–214

8. Magnification 10. Magnification 18. Gary B. Carr, Carlos A.F. Murgel . The Use of the Operating Microscope in Endodontics. Dent Clin N Am 54 (2010) 191–214

9. Several elements are important for consideration in improving clinical visualization. Stereopsis Magnification range Depth of field Resolving power Working distance Spherical and chromatic distortion ( ie , aberration) Ergonomics Eyestrain Head and neck fatigue Cost. Gary B. Carr, Carlos A.F. Murgel . The Use of the Operating Microscope in Endodontics. Dent Clin N Am 54 (2010) 191–214

10. Considering the problem of the uncomfortable proximity of the practitioner’s face to the patient, moving closer to the patient is not a satisfactory solution for increasing a clinician’s resolution. As the eye-subject distance ( i.e , focal length) decreases, the eyes must converge, creating eyestrain. Gary B. Carr, Carlos A.F. Murgel . The Use of the Operating Microscope in Endodontics. Dent Clin N Am 54 (2010) 191–214

11. As one ages, the ability to focus at closer distances is compromised. “ Presbyopia ”: caused by the lens of the eye losing flexibility with age. The eye (lens) becomes unable to accommodate and produce clear images of near objects. Gary B. Carr, Carlos A.F. Murgel . The Use of the Operating Microscope in Endodontics. Dent Clin N Am 54 (2010) 191–214

12. The nearest point that the eye can accurately focus on exceeds ideal working distance. Alternatively, image size and resolving power can be increased by using lenses for magnification, with no need for the position of the object or the operator to change. Gary B. Carr, Carlos A.F. Murgel . The Use of the Operating Microscope in Endodontics. Dent Clin N Am 54 (2010) 191–214

13. A brief history of magnification Hans and Zacharias Jansen (1595) Simple (single lens) and compound (two lenses) microscopes. Robert Hooke (1665) Using a compound microscope, coined the word ‘cell’ while describing features of plant tissue.

14. Anton van Leeuwenhoek (1674) produced single lenses powerful enough to enable him to observe bacteria 2–3  μm in diameter. Carl Zeiss , Ernst Abbe , and Otto Schott devoted significant time to develop the microscope.

15. Evolution of magnification and illumination in medicine In 1921, Dr Carl Nylen of Germany: Monocular microscope for operations to correct chronic otitis of the ear. The unit had two magnifications of × 10 and × 15 and a 10 mm diameter view of the field. This microscope had no illumination.

16. In 1922, the Zeiss Company (Germany) working with Dr Gunnar Holmgren of Sweden, Introduced a binocular microscope for treating otosclerosis of the middle ear. This unit had magnifications of × 8–× 25 with field-of-view diameters of 6–12 mm The formal introduction of the binocular operating microscope took place in 1953 when Zeiss introduced the Opton ear microscope.

17. Evolution of magnification and illumination in dentistry In 1876, Dr Edwin Saemisch , a German ophthalmologist, introduced simple binocular loupes to surgery. Soon after, dentists began experimenting with loupes to assist in the performance of precision dentistry and this continued to be the practice until the late 1970s.

18. In 1962, Dr Geza Jako , an otolaryngologist, used the SOM in oral surgical procedures. In 1978, Dr Harvey Apotheker , a dentist from Massachusetts, and Dr Jako began the development of a microscope specifically designed for dentistry.

19. In 1980, Dr Apotheker coined the term ‘ microdentistry ’ The ‘ DentiScope ’ (1981) was manufactured by Chayes -Virginia Inc., USA, and marketed by the Johnson and Johnson Company Dr Gabriele Pecora gave the first presentation on the use of the Dental Operating Microscope (DOM) in surgical endodontics at the 1990 annual session of the American Association of Endodontists in Las Vegas, Nevada.

20. Gary Carr (1999): Introduced a DOM that had Galilean optics and that was ergonomically configured for dentistry, with several advantages that allowed for easy use of the scope for nearly all endodontic and restorative procedures.

21. Loupes Historically, dental loupes have been the most common form of magnification used in apical surgery. Loupes are essentially two mono-ocular microscopes with lenses mounted side by side and angled inward ( convergent optics ) to focus on an object.

22. Oculars (loupes) rely on convergent vision that essentially requires an overlap of two images. This form of magnification creates increasing problems and eye strain as magnification power increases. The clinical microscope utilizes a more refined optical system

23. × 2.5 and × 3.5 dental loupes (Designs for Vision, Ronkonkoma, NY, USA).

24. The disadvantage of this arrangement is that the eyes must converge to view an image. This convergence over time will create eyestrain and fatigue and, as such, loupes were never intended for lengthy procedures. Most dental loupes used today are compound in design and contain multiple lenses with intervening air spaces.

25. This is a significant improvement over simple magnification eyeglasses but falls short of the more expensive prism loupe design. Prism loupes: are actually low-power telescopes that use refractive prisms .

26. Prism loupes produce better magnification, larger fields of view, wider depths of field, and longer working distances than other types of loupes. Only the Dental Operating Microscope (DOM) provides better magnification and optical characteristics than prism loupes.

27. Depth of field refers to the ability of the lens system to focus on objects that are both near and far without having to change the loupe position. As magnification increases, depth of field decreases.

28. Also, the smaller the field of view, the shallower the depth of field. Depth of field is approximately 5 inches (12.5 cm) for a 2x loupe, 2 inches (6 cm) for a 3.25x loupe, and 1 inch (2.5 cm) for a 4.5x loupe.

29. The disadvantage of loupes is that × 3.5–× 4.5 is the maximum practical magnification limit. Loupes with higher magnification are available but they are quite heavy and if worn for a long period of time can produce significant head, neck, and back strain.

30. In addition, as magnification is increased, both the field of view and depth of field decrease, which limits visual opportunity. Visual acuity is heavily influenced by illumination. An improvement to using dental loupes is obtained when a fiberoptic headlamp system is added to the visual armamentarium.

31. Surgical headlamps can increase light levels as much as four times that of traditional dental operatory lights. Another advantage of the surgical headlamp is that since the fiberoptic light is mounted in the center of the forehead, the light path is always in the center of the visual field.

32. Loupes are classified by the optical method in which they produce magnification . Diopter , flat-plane, single-lens loupe, Surgical telescope with a Galileian system configuration (two lens system), Surgical telescope with a Keplarian system configuration (prism roof design that folds the path of light). Gary B. Carr, Arnaldo Castellucci . The Use of the Operating Microscope in Endodontics.

33. 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 ). Gary B. Carr, Arnaldo Castellucci . The Use of the Operating Microscope in Endodontics.

34. A lens with 2 D designation would focus to 50 cm (19 inches); a 5 D lens would focus to 20 cm (8 inches). Confusion occurs when a diopter single-lens magnifying system is described as 5 D. This does not mean 5x power (5 times the image size). 5 D: the focusing distance of the eye to the object is 20 cm (less than 8 inches) with an increased image size of approximately 2x (2 times actual size). Gary B. Carr, Arnaldo Castellucci . The Use of the Operating Microscope in Endodontics.

35. The surgical telescope of either Galileian or Keplarian design produce an enlarged viewing image with a multiple lens system positioned at a working distance between 11 and 20 inches (28-51 cm). The most used and suggested working distance is between 11 and 15 inches ( 28-38 cm ). Gary B. Carr, Arnaldo Castellucci . The Use of the Operating Microscope in Endodontics.

36. The Galileian system provides a magnification range from 2x up to 4.5x and is a small, light and very compact system. The prism loupes ( Keplarian system) use refractive prisms and they are actually telescopes with complicated light paths, which provide magnifications up to 6x Gary B. Carr, Arnaldo Castellucci . The Use of the Operating Microscope in Endodontics.

37. An example of a Galilean system Prism loupes. These loupes have sophisticated optics, which rely on internal prisms to bend the light.

38. Endoscopy Endoscopy is a surgical procedure whereby a long tube is inserted into the body usually through a small incision. It is used for diagnostic, examination, and surgical procedures in many medical fields. Goss and Bosanquet reported that Ohnishi first used the endoscope in dentistry to perform an arthroscopic procedure of the temporomandibular joint in 1975.

39. Detsch et al. (1979) first used the endoscope in endodontics to diagnose dental fractures. Held et al. and Shulman & Leung (1996) reported the first use of the endoscope in surgical and non-surgical endodontics. Bahcall et al. (1999) presented an endoscopic technique for endodontic surgery.

40. The endoscopic system consists of a telescope with a camera head, a light source, and a monitor for viewing. The traditional endoscope used in medical procedures consists of rigid glass rods and can be used in apical surgery and non-surgical endodontics.

41. A 2.7 mm lens diameter, a 70° angulation , and a 3 cm long rod-lens are recommended for surgical endodontic visualization.

42. A 4 mm lens diameter, a 30° angulation , a 4 cm long rod-lens are recommended for non-surgical visualization through an occlusal access opening. Flexible fiberoptic orascope recommended for intracanal visualization, has a .8 mm tip diameter, 0° lens, and a working portion that is 15 mm in length. Bahcall J , Barss J. Orascopic visualization technique for conventional and surgical endodontics. Int Endod J 2003: 36: 441–447.

43. The term orascopy describes the use of either the rigid rod-lens endoscope or the flexible orascope in the oral cavity. Endodontic Visualization System (EVS) (JEDMED Instrument Company, St Louis, MO, USA) incorporates both endoscopy and orascopy into one unit.

44. Endodontic visualization system utilizing a fixed rod lens for apical surgery

45. Clinicians who use orascopic technology appreciate the fact that it has a non-fixed field of focus, which allows visualization of the treatment field at various angles and distances without losing focus and depth of field. Critics of this form of magnification point out that the images viewed are two-dimensional and too restrictive to be useful when compared with the stereoscopic images provided with loupes or microscopes.

46. Dental Operating Microscope (DOM) Most microscopes can be configured to magnifications up to × 40 and beyond but limitations in depth of field and field of view make it impractical. The lower-range magnifications (× 2.5–× 8) are used for orientation to the surgical field and allow for a wide field of view. Mid-range magnifications (× 10 –× 16) are used for operating.

47. Global G-6 SOM (Global Surgicalt Corporation, St Louis, MO, USA) with an enhanced metal halide illumination system. JEDMED V-Series SOM with assistant binoculars, a three-chip video camera, and counter balanced arms.

48. Zeiss OPMI PROergo (Carl Zeiss Surgical Inc., Thornwood, NY, USA) with magnetic clutches, power zoom, and power focus on the handgrips.

49. Higher-range magnifications (× 20 –× 30) are used for observing fine detail. The most significant advantages of using the DOM are in visualizing the surgical field and in evaluating surgical technique.

50. Magnification The magnification possibilities of a microscope are determined by; the power of the eyepiece, the focal length of the binoculars, the magnification changer factor, and the focal length of the objective lens.

51. Diopter settings on the eyepieces adjust for accommodation and refractive error of the operator. As in a typical pair of field binoculars, adjusting the distance between the two binocular tubes sets the interpupillary distance. Binoculars are now available with variable inclinable tubes from 0° to 220° to accommodate virtually any head position.

52. Magnification changers are available in 3-, 5-, or 6-step manual changers, manual zoom, or power zoom changers. Manual step changers consist of lenses that are mounted on a turret.

53. Cross-sectional diagram of a typical 5-step SOM head showing the turret ring in the body of the microscope.

54. The turret is connected to a dial, which is located on the side of the microscope housing. The dial positions one lens in front of the other within the changer to produce a fixed magnification factor. Rotating the dial reverses the lens positions and produces a second magnification factor.

55. Turning the dial rotates the turret ring inside the body of the SOM and creates five magnification factors.

56. Total magnification of a microscope: TM = (FLT/FLOL) × EP × MV FLT: Focal length of tube FLOL: Focal length of objective lense EP: Eyepiece Power MV: Magnification Value

57. The focal length of the objective lens determines the operating distance between the lens and the surgical field. With the objective lens removed, the microscope focuses at infinity. Many endodontic surgeons use a 200 mm lens, which focuses at about 8 in. With a 200 mm lens there is adequate room to place surgical instruments and still be close to the patient.

58. Increase in the magnification, decreases the depth of field and field of view. While this is a limitation for fixed magnification loupes, it is not a limiting factor with the DOM because of the variable ranges of magnification. If the depth of field or field of view is too narrow, the operator merely needs to back off on the magnification as necessary to view the desired field.

59. Low range Magnification: (×2.5 - ×8). Orientation of surgical field & allows wide inspection of the field of view. Mid range Magnification: (×8 - ×14). Surgical procedure including curettage of the granulation tissue, resection of root tip, root –end preparation, & root –end filling. High range Magnification: (×14 - ×30). Observing the finer details & documentation purposes. Grossman’s Endodontic Practice. 12 th Edition

60. Illumination The light provided in an DOM is two to three times more powerful than surgical headlamps and, in many endodontists offices. The light enters the microscope and is reflected through a condensing lens to a series of prisms and then through the objective lens to the surgical field.

61. After the light reaches the surgical field, it is then reflected back through the objective lens, through the magnification changer lenses, through the binoculars, and then exits to the eyes as two separate beams of light. The separation of the light beams is what produces the stereoscope effect that allows us to see depth.

62. Illumination with the DOM is coaxial with the line of sight. This means that light is focused between the eyes in such a fashion that you can look into the surgical site without seeing any shadows. Elimination of shadows is made possible because the DOM uses Galilean optics.

63. Galilean optics focus at infinity and send parallel beams of light to each eye. With parallel light, the operator's eyes are at rest and therefore lengthy operations can be performed without eye fatigue.

64. Galilean optics. Parallel optics enables the observer to focus at infinity, relieving eyestrain.

65. Accessories A beam splitter can be inserted into the pathway of light as it returns to the operator's eyes. The function of the beam splitter is to supply light to an accessory such as a video camera or digital still camera. In addition, an assistant articulating binocular can be added to the microscope array.

66. Doctor and assistant at the surgical operating microscope.

67. Advantages Manuel García Calderón et al. The application of microscopic surgery in dentistry. Med Oral Patol Oral Cir Bucal 2007;12:E311-6.

68. Increased Visualization: Human eye, when unaided by magnification, has the inherent ability to resolve or distinguish two separate lines or entities that are at least 200 microns, or 0.2mm, apart. Most people cannot refocus at distances closer than 10 to 12 cm. DOM can raise the resolving limit from 0.2 -0.006 mm

69. 2. Improved Quality and precision of treatment: A microscope at 10× magnification provides 25 times the information compared to that obtained through the use of entry-level loupes (2×) and over 10 times that of 3× power loupes

70. Shanelec and Tibbets [1998] Working without magnification, can make movements that were 1–2 mm at a time. At 20× magnification, the refinement in movements can be as little as 10–20 microns (10–20/1000 of a mm) at a time. Tibbets LS, Shanelec DA. Periodontal Microsurgery. Dent Clin North Am. 1998; 42:339–359.

71. Leknius and Geissberger , [1995] and Zaugg et al. (2004): As magnification is incorporated, procedural errors decrease significantly. The inclusion of a microscope resulted in fewer errors than when a set of loupes was used. Leknius C, Geissberger M. The Effect of Magnification on the Performance of Fixed Prosthodontic Procedures. J Calif Dent Assoc. 1995; 23(12):66–70. Zaugg B, Stassinakis A, Hotz P. Influence of Magnification Tools on the Recognition of Simulated Preparation and Filling Errors. Schweiz Monatsschr Zahnmed . 2004; 114(9):890–896.

72. The figure features 8x convergent magnification with loupes and a representation of the two images that the brain receives as the eyes begin to focus. The figure shows a common occurrence of the incomplete merging of the images seen through a pair of loupes The figure represents the same case seen with a clinical microscope at 24x original magnification featuring infinity corrected optics. There is no eye strain and no visual noise. Loupes magnification at 8x (original magnification) and beyond becomes excruciating for most clinicians. David J. Clark. Operating Microscopes and Zero-Defect Dentistry Journal canadien de dentisterie restauratrice et de prosthodontie . December 2008

73. 3. Improved & Ideal treatment Ergonomics The binoculars on many DOMs have variable inclination. This means that the operator's head can develop and maintain a comfortable position. All stooping and bending is eliminated, thereby forcing the operator to sit up straight tilting the pelvis forward and aligning the spine in proper position.

74. This positioning should create a double s-curvature of the spine, with lordosis in the neck, kyphosis in the mid-back, and lordosis again in the lower spine. Such posturing is not possible when the clinician is wearing a headlamp and loupes or using an endoscope. With these devices, there is still the tendency to bend over the patient, creating poor ergonomics and developing head, neck, and shoulder strain.

75. Constant bending over the patient collapses the diaphragm and may inhibit oxygen exchange causing fatigue later in the workday. This is eliminated with the upright positioning achieved while using the DOM. Microscopes with a long working distance allow distance from the patient, reducing the risk of exposure to aerosols and spatter.

76. THE LAWS OF ERGONOMICS Class I motion: moving only the fingers Fingers waiting for the file. (B) File placed in between fingers. (C) Fingers capturing file.

77. Class II motion: moving only the fingers and wrists Hand waiting for the instrument. (B) Fingers and wrist movement receiving the instrument. (C) Fingers movement receiving the instrument.

78. Class III motion: movement originating from the elbow Elbow rested at the stool support. (B) Supported elbow rotation and instrument apprehension. (C) Supported elbow rotation to working position.

79. Class IV motion: movement originating from the shoulder Class V motion: movement that involves twisting or bending at the waist. Professional at the neutral position. (B) Shoulders, arms, elbows, and hands moving to reach the OM. (C) OM moved to the ideal position without rotational movement of the waist

80. Positioning the DOM In chronologic order, the preparation of the OM involves the following maneuvers : Operator positioning Rough positioning of the patient Positioning of the OM and focusing Adjustment of the interpupillary distance Fine positioning of the patient Parfocal adjustment Fine focus adjustment Assistant scope adjustment.

81. Operator Positioning At the 11- or 12-o’clock position 9-o’clock position may seem more comfortable when first learning to use an DOM, but as greater skills are acquired, changing to other positions rarely serves any purpose. Clinicians who constantly change their positions around the scope are extremely inefficient in their procedures.

82. The hips are 90˚ to the floor, the knees are 90˚ to the hips, and the forearms are 90˚ to the upper arms. The eyepiece is inclined so that the head and neck are held at an angle that can be comfortably sustained. This position is maintained regardless of the arch or quadrant being worked on. The patient is moved to accommodate this position.

83. The trapezius , sternocleidomastoid , and erector spinae muscles of the neck and back are completely at rest in this position. Once the ideal position is established, the operator places the OM on one of the lower magnifications to locate the working area in its proper angle of orientation. The image is focused and stepped up to higher magnifications if desired.

84. Operatory Design Principles for using DOM The organizing design principle using the OM in the dental operatory should revolve around an ergonomic principle called circle of influence.

85. 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.

86. Team work development: doctor and assistant working erect and muscularly relaxed. Adjustable cart allowing access to all instruments, using only a class III motion.

87. Small movement of the chair to the left (note that patient’s head is tilted a little to the left If necessary, the patient’s head is moved slightly to the right to compensate chair movement (Note that the OM was not touched at any time).

88. Elbow support for doctor and assistant is mandatory to allow the necessary fine motor skills under constant magnification and muscular comfort throughout the day.

89. 4. Ease of Proper Digital Documentation Capabilities; The video camera mounted on the microscope's beam splitter sends a real-time video signal and an unlimited number of images can be captured or recorded during the procedure. These images can then be saved along with radiographic images and reviewed with the patient after the surgery.

90. Digital radiographs and clinical images on 19′ flat panel LCD screen.

91. 5. Increased Ability to Communicate through Integrated Video Mehrabian : 55% of the understanding that occurs in verbal communication is through visual cues, and only 7% of the comprehension comes from the words. Useful in providing information both to patients and to auxiliaries. Glenn A. van As:Digital Documentation and the Dental Operating Microscope: what you see is what you get: Int J Microdent 2009;1:30–41.

92. Microscope with Nikon Digital SLR camera on the right side, a Nikon SB-29 ring flash mounted at the bottom, and a Sony three-chip digital medical-grade cube camera on the left side.

93. Disadvantages Need for specific training: as a DOM has a restricted working field, 11mm -55mm An operator using a DOM can see only the tip of the instruments, and they are used in delicate movements of small amplitude High initial cost of the equipment and instruments

94. Misconceptions about surgical microscopes Magnification : ‘How powerful is your microscope’? The question really addresses the issue of useable power. Useable power is the maximum object magnification that can be used in a given clinical situation relative to depth of field and field of view. ‘How useable is the maximum power’? While magnification in excess of × 30 is attainable, it is of little value while performing apical surgery.

95. Working at a higher magnification is extremely difficult because slight movements by the patient continually throw the field out of view and out of focus. The operator is then constantly re- centering and refocusing the microscope.

96. This wastes a considerable amount of time and creates unnecessary eye fatigue. Those clinicians who use the endoscope for apical surgery would also agree that higher magnifications are for critical evaluation only and not for operating.

97. Illumination There is a limit to the amount of illumination that an DOM can provide. As the magnification is increased, there is decrease in the effective aperture of the microscope and therefore limit the amount of light that can reach the surgeon's eyes. This means that as higher magnifications are selected, the surgical field will appear darker.

98. Depth Perception : Before apical surgery can be performed with an DOM, the clinician must feel comfortable receiving an instrument from his assistant and placing it between the microscope and the surgical field. Learning depth perception and orientation to the microscope takes time and patience.

99. Use of Dental Operating Microscope Examination, diagnosis, and treatment planning: To identify a microscopic blemish, colour alteration, tiny amounts of plaque collecting within the grooves. Chalky white demineralization around the grooves, and tiny amounts of flaking of darkened carious tooth structure within the crevices of these grooves.

100. 2. Diagnosis of cracked teeth Microfractures and longitudinal fractures Cracks in teeth or restorations, craze lines, wear facets, cracks at slightly elevated marginal ridges. Microfracture diagnosed during orthograde root canal treatment. Microfracture diagnosed during microsurgical endodontic treatment

101. 3. Better visualization of pulp chamber, canal orifices Better identify anatomical landmarks, within the pulp chamber—including the sides, overhanging remnants of the pulp chamber roof, initial perforations into the pulp, dentinal map, canal orifices and, To differentiate between the pulp horns and the main body of pulp within the chamber.

102. 4. During instrumentation: The improved ability to see specific canals allows endodontists to maneuver files into canal openings with greater efficiency. To determine if all canals are accessed and instrumented properly when a direct view might be difficult without removing excessive amounts of coronal tooth structure.

103. 5. Locating hidden canals/canal systems Anatomical variations are not as rare or exotic as is frequently assumed. The introduction of the dental microscope and the associated ability to inspect the root canals.

104. 6. Identification and removing of Obliterations and calcifications: These signs occur to a greater or lesser extent in 50% of all teeth, impairing instrumentation considerably or essentially preventing treatment of the canal system. Obliterated canal orifices impair instrumentation or even prevent root canal treatment.

105. 7. Identification and removal of Denticles : This specific form of calcification is also encountered very frequently, can block the canal entrance or even obstruct further instrumentation. Denticles can be found and negotiate readily with the help of a DOM Denticles may block the canal entrance

106. 8. In Open apex cases: Modern apexification therapies call for special treatment techniques and materials, the manipulation of which is facilitated significantly under a dental microscope. 9. Perforation repair:

107. 10. Removal of fractured post and instruments The enhanced vision with magnification and illumination from a microscope allows endodontist to observe the most coronal aspects of fractured post and broken instruments and to remove them without any major loss of tooth structure and perforations, the prognosis for preservation of the tooth is quite good.

108. 11. Apical microsurgery Flap design, flap reflection, flap retraction, Osteotomy , periapical curettage, Biopsy, hemostasis , Apical resection, resected apex evaluation, apical preparation, apical preparation evaluation, drying the apical preparation, Selecting retrofilling materials, mixing retrofilling materials, placing retrofilling materials, Compacting retrofilling materials, carving retrofilling materials, finishing retrofilling materials, Documenting the completed retrofill , and tissue flap closure.

109. A selection of flexible mirrors in different sizes and shapes. (B) Detail of highly reflective mirrors with flexible and flat shafts.

110. After anesthesia is obtained, micro-scalpels ( SybronEndo , Orange, CA, USA) are used in the design of the tissue flap to incise delicately the interdental papillae when full-thickness flaps are required. Vertical incisions are made ½ to two times longer than in traditional apical surgery to assure that the tissue can be easily reflected out of the light path of the microscope.

111. A variety of micro scalpels sized 1-5 used for precise incision.

112. Flap Design and Suturing Incising and reflecting soft-tissue flaps are not high-magnification procedures. In many cases, they can be performed with the naked eye or with low-power loupes. Basic single interrupted stitch suturing can also be performed with little to no magnification. While the microscope could be used at low magnification, little is gained from its use in these applications.

113. However, with the introduction of the delicate papilla base incision, which requires the use of 7-0 sutures and a minimum of two sutures per papilla microscopic magnification, with a minimum of × 4.3, is suggested. The DOM is used at its best advantage for osteotomy , apicoectomy ( apicectomy ), apical preparation, retrofilling , and documentation. Velvart P. Papilla base incision: a new approach to recession-free healing of the interdental papilla after endodontic surgery. Int Endod J 2002: 35: 453–460.

114. Access One of the problems encountered in apical surgery is gaining physical access to the sight of infection. The DOM will not improve access to the surgical field. If access is limited for traditional surgical approaches, it will be even more limited when the microscope is placed between the surgeon and the surgical field.

115. Use of the DOM, however, will create a much better view of the surgical field. This is particularly true in diagnosing craze lines and cracks along the bevelled surface of a root or when the surgeon is preparing a tiny isthmus between two canals ultrasonically.

116. Because vision is enhanced so dramatically, apical surgery can now be performed with a higher degree of confidence and accuracy. Repeated use of the microscope and concurrent stereoscopic visualization will help the clinician develop visual imagery of the various stages of apical surgery, which is necessary in learning sophisticated surgical skills.

117. Because the DOM enhances vision, bone removal can be more conservative. Handpieces such as the Impact Air 45™ ( SybronEndo ), introduced by oral surgeons to facilitate sectioning mandibular third molars, are also suggested for apical surgery to gain better access to the apices of maxillary and mandibular molars.

118. When using the handpiece, the water spray is aimed directly into the surgical field but the air stream is ejected out through the back of the handpiece, thus eliminating much of the splatter that occurs with conventional high-speed handpieces . Because there is no pressurized air or water, the chances of producing pyemia and emphysema are significantly reduced.

119. Burs such as Lindemann bone cutters ( Brasseler USA, Savannah, GA, USA) are extremely efficient and are recommended for hard-tissue removal. They are 9 mm in length and have only four flutes, which result in less clogging. With the use of an DOM, the Impact Air 45™ and high-speed surgical burs can be placed even in areas of anatomical jeopardy with a high degree of confidence and accuracy.

120. Impact Air 45™ and surgical length bur in close proximity to the mental nerve × 8.

121. With the DOM, periapical curettage is facilitated because bony margins can be scrutinized for completeness of tissue removal. Rubinstein and Kim [1999] Healing in 96.8% of cases in the short term, and 91.5% in the long term follow-up is well beyond the success rates of conventional apicoectomy procedures.

122. There are others such as external cervical invasive resorption repairs, removing materials such as solid obturation materials (silver points and carrier-based materials), and other resorptive repairs that also benefit from a microscopic approach.

123. Restorative Procedures Caries detected under cusps, through magnification Arrows show crack in ceramic restoration Jose Roberto Moura Jr. Operating microscopes in restorative dentistry: The pursuit of excellence. Int Dent SA 2006; 10(5): 4-11. J Minim Interv Dent 2009; 2 (4)

124. Small cavity can be seen in proximal surface of inferior incisor Gap can be seen between all ceramic crowns and preparation at 25 X magnification Jose Roberto Moura Jr. Operating microscopes in restorative dentistry: The pursuit of excellence. Int Dent SA 2006; 10(5): 4-11. J Minim Interv Dent 2009; 2 (4)

125. Bubble within adhesive being applied to tooth, if not detected, may prevent proper hybridization in that spot. Dental cracks and incomplete fractures that used to be diagnosed by symptom basis, Jose Roberto Moura Jr. Operating microscopes in restorative dentistry: The pursuit of excellence. Int Dent SA 2006; 10(5): 4-11. J Minim Interv Dent 2009; 2 (4)

126. Excess luting cement identified that can be carefully removed under proper magnification Remaining caries visually detected in gingival margin of proximal cavity Jose Roberto Moura Jr. Operating microscopes in restorative dentistry: The pursuit of excellence. Int Dent SA 2006; 10(5): 4-11. J Minim Interv Dent 2009; 2 (4)

127. Conclusion Microscope-enhanced dentistry is changing the endodontic-restorative protocol, altering the thought process when determining when to save or extract a tooth. Microscopes offer additional methods for caries assessment and endodontic therapy, moving the profession closer to zero-defect restorative dentistry.

128. With advanced magnification, the additional visual information afforded to the clinician with the benefit of shadow-less, coaxial light combined with infinity corrected optics enhances the clinician’s ability to create clean, caries free margins, which, in turn, can create an optimal restorative seal.

129. Exact therapy requires exact vision. High-quality endodontic therapy is the basis for long-term function and biologic success, ensuring that patients remain free of pain. Shift in clinical accuracy from low magnification ―tactile-driven endodontics to ―vision-based endodontics is bringing a revolution to the field of endodontics with greater success rate.

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