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Rotary instruments / dental implant courses by Indian dental academy 


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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
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Rotary instruments / dental implant courses by Indian dental academy 

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing Dental Education
  2. 2. CONTENTSCONTENTS  Introduction  History and development  Principles of Rotary instruments  Instrument Parts and Design  Instrument types  ISO Standardization  Manufacturing  Efficiency  Clinical Considerations  Recent advances  Sterilization and Infection control  Summary  References
  3. 3. INTRODUCTIONINTRODUCTION The removal and shaping of tooth structure is an essential part of restorative and prosthetic dentistry. Initially this was a difficult process accomplished entirely by the use of hand instruments. The introduction of rotary equipments, air abrasives and lasers is one of the truly major advances in dentistry.
  4. 4. Rotary cutting instruments: They are engine driven instruments revolving around their long axis. Bur : A cutting or drilling bit . (Webster’sDictionary) A surgeon’s or dentist’s small drill. (Oxford Dictionary) A steel or tungsten carbide rotary cutting instrument. (GPT-7) Diamond points: They are rotary cutting tools, consisting of an inner steel shank over which industrial diamonds of different grits are either electroplated with Ni or are sintered with a metal matrix.
  5. 5. HISTORY AND DEVELOPMENTHISTORY AND DEVELOPMENT “The only guide to what lies ahead is in the past.” 5000 B.C. Early drills from the time of Hippocrates 287-212 B.C. Archimedian instruments
  6. 6. 1700s Mechanical drilling device turned with a hand crank Invented by Jourdain and described by Fauchard 1790 First foot- powered dental engine by J.Greenwood
  7. 7. 1803 Crank operated gear drill by Von Lautenschlager 1838 Egg-beater drill invented by J.Lewis First patented drill
  8. 8. 1846 Wescott introduced the finger ring with drill socket 1850s G.F.Green invented the first electric dental engine with a self contained motor and hand piece
  9. 9. 1858 Charles Merry introduced this drill stock with two hand pieces :one retained the rotating drill in position, the other propelled it. 1864 Harrington introduced the first motor driven dental engine
  10. 10. 1870 George F.Green invented the first electric dental engine, was a self contained motor and hand piece 1871 James B. Morrison invented the foot-treadle dental engine
  11. 11. 1874 Bonwill dental engine- the first continuous cord engine with compensating points 1875 S.S. White Dental Engine- Battery operated
  12. 12. 1902 First folding bracket engine Cord type Cable
  13. 13. Around 1915 Dariot hand piece used with continuous cord dental engine 1950s S.S. White hand piece no.7 Used with cable dental engines
  14. 14. 1950s Midwest needle ball-bearing hand piece with Trans speed of 50,000 to 100,000 rpm 1950s Airbrasive non rotary drills were introduced
  15. 15. 1958 Page-Chayes hand piece –the first belt driven hand piece 1950s Turbo-Jet -the first water driven turbine hand piece
  16. 16. 1957 Borden Airotor Hand piece-the first air-driven hand piece with a running speed of about 300,000 rpm In Modern times: LASERS have also been considered as an option
  18. 18. ABRASION  Abrasion : Process of finishing a restoration involving abrasive wear through the use of hard particles.  Abrasive : A hard substance used for grinding, finishing or polishing a less hard surface.  Substrate : The material being finished by an abrasive.  Rotational direction is an important factor in controlling the instrument action on the substrate surface.  Two processes : Two body abrasion Three body abrasion.  Hardness of abrasive should be higher than the substrate.  Mohs scale : Diamond – 10 Tungsten carbide – 9.8 Enamel – 5 Dentine – 3 to 4 .  Speed for-cutting : 5000 feet per min -polishing : 7500 to 10000 feet per
  20. 20. INSTRUMENT PARTSINSTRUMENT PARTS Bur head : the cutting portion of a dental bur. Bur head length : the axial dimension of the bur head. Bur head shape : the geometrical outline form of the cutting surface edges, usually described successively by proximity from the shank to the tip end. Bur shank : that component of a dental bur which fits into the hand piece ; the shaft section of a dental bur that may be friction gripping or latch type in form. (GPT –7 JPD 1999;81:56 )
  21. 21.  Blade or cutting edge : is in contact with horizontal line or work .  Tooth face : side of the tooth ahead of cutting edge in the direction of rotation.  Back or flank of tooth : the opposite of the face or following surface.  Tooth angle : angle between front and back (flank) of the teeth of bur. INSTRUMENT DESIGNINSTRUMENT DESIGN
  22. 22.  Flute space : space in between back of one tooth and front of next tooth.  Clearance angle : angle between a back (flank) of tooth and work. Primary & Secondary clearance angle are incorporated to increase the efficiency and decrease clogging. Primary clearance angle : angle between the tooth and work. Secondary clearance angle : angle between back and work.
  23. 23. Rake angle : angle between front of the tooth and radial lines. Zero rake angle(radial rake angle) – where the radial line and the face contour correspond. Positive rake angle : when the radial line leads the face so that rake angle is on inside of radial line. Negative rake angle : when the face is beyond or leading the radial line in reference to the direction of rotation.
  24. 24. Positive rake angle Thinner and sharper teeth More temperature rise Less life Used for cutting soft & weak materials. Possesses greater efficiency Has lesser edge strength. Negative rake angle Broader teeth Less temperature rise More life For hard brittle materials. Possesses lesser efficiency Has greater edge strength.
  25. 25. INSTRUMENT TYPES Burs – cutting tools Stones or points – abrading tools (grinding ) Classification : A)Depending upon source of power: 1. Air driven 2. Electric driven B)Depending upon hand piece to which it is attached: 1. Screw in type -air motor hand piece (straight) 2. Latch type -micromotor (contra angled hand piece) 3. Friction grip type
  26. 26. C)Depending upon the speed of hand piece to which they are attached: Ultra low - 300 to 3000 rpm Low - 3000 to 6000 rpm Medium - 20 to 45 K rpm High speed - 45 to 100 K rpm Ultra high - 100 K rpm D)Based on the material used: Steel Tungsten carbide Diamond E) According to shape
  27. 27. ISO STANDARDIZATIONISO STANDARDIZATION ISO 6360 identified completely any bur In terms of :
  28. 28. A) Material of its working part Stainless steel – 330 Tungsten carbide – 500 Aluminum oxide – 615,625,635 Diamond – 806,807 B) Shank form Type of instrument ISO Number Shank length Shank diameter Standard hand piece bur 103 104 105 34 mm 44 mm 65 mm 2.35 mm Hand piece bur 124 3 mm Contra angled standard 202 204 205 206 16 mm 22 mm 26 mm 34 mm 2.35 mm Standard friction grip 313 314 315 316 16 mm 19 mm 21 mm 25 mm 1.60 mm Unmounted grinding points
  29. 29. C) Shape of the working part Round head – 001 Inverted cone – 010 Cylindrical – 107 Conical – 168 Pear shaped – 237 Flame shaped - 243 Bud shaped – 260 Torpedo shaped – 284 Lens shaped – 303 Disks – 320 E) Largest diameter of the working part (measured in one – tenth of mm) 008 =0 .8mm 220 = 22mm D) Grit size Super fine (15 microns) – 494 Extra fine (30 microns) – 504 Fine ( 50 microns) – 514 Medium Grit (100 to 120 microns) – 524 Coarse grit (135 to 140 microns) – 534 Extra coarse (180 microns) – 545
  30. 30. MANUFACTURINGMANUFACTURING STEEL BURS: These are cut from blank steel stock by means of a rotary cutter that cuts parallel to the long axis of bur. Bur is then hardened and tempered. TUNGSTEN CARBIDE BURS: Are a product of powder metallurgy. Tungsten carbide powder is mixed with powdered cobalt under pressure and heated in vaccum. A blank is then formed and the bur is cut from it with a diamond tool DIAMOND POINTS: 1. Electrolytic deposition 2. Brazing 3. Sintering
  31. 31. Abrasive particles are bonded by four methods: 1. Sintering : sintered abrasives are the strongest type as the particles are fused together. 2. Vitreous bonding : abrasives are mixed with glassy or ceramic matrix material, cold pressed to the instrument shape, and fired to fuse the binder. 3. Resinoid bonding : abrasives are cold pressed or hot pressed and then heated to cure the resin. Hot pressing yields an abrasive binder with extremely low porosity. 4. Rubber bonding : abrasives are made in a manner similar to that for resin bonded abrasives.
  32. 32. Recent advances : Chemical vapour deposition allows for the fabrication of new burs with continuous diamond film (pure diamond cutter without metallic binder) and offers promising perspectives with regard to cutting ability and longevity. (JPD 1999;82:73-9)
  33. 33. EFFICIENCY Depends upon: 1. Tooth angle 2. Clearance angle 3. Rake angle 4. Speed 5. Load or pressure SIEGEL etal studied the cutting efficiencies of diamond dental burs using different hand piece loads with ultra high speed. Results: _Optimum hand piece load at bur tip :100g _ Below it : CE decreases _Above it : For medium grit burs : no effect For coarse grit burs : CE increases (with increase in temp.) (J.Prosthod.1999;8:3-9)
  34. 34. 6. Eccentricity 7. Run out 8. Coolants:  Study conducted by FRAUNHOFER etal to evaluate the effect of hand piece coolant flow rates on cutting efficiency : Result Use of higher coolant flow rate (25 to 44 ml per min ) increases CR . (Operative Dentistry 2000; 544-8)
  35. 35. Study conducted by SIEGELetal to evaluate the effect of coolant water containing mouthwash additives at various concentration on cutting rate
  36. 36. 9.Grit size Study conducted by SIEGEL etal to compare the cutting rates of medium, coarse, supercoarse diamond burs. (JADA 2000;131 : 1706-10)
  37. 37. CLINICAL CONSIDERATIONSCLINICAL CONSIDERATIONS LOCAL CONSIDERATIONS: 1. Heat generation Steel greater than carbide Diamond greater than carbide Dull or clogged instruments will produce more heat. VANGHN and PEYTON concluded: -maximum temperature rise is developed with in 10 sec after operation begins. -smaller the size of cutting instrument lower the temperature rise -increased pressure and increased speed increases the temperature rise. ( JADA 1956;53:298-304 )
  38. 38. 2. Soft tissue injury 3. Infection transmission 4. Hearing damage: Air turbine hand piece at high speed produces high pitch. Protection mandatory when 95 db is reached. Normal hand piece use per day – 30 min per day. 2. Pulpal injury Due to mechanical vibration Heat generation Dessication Loss of dentinal tubule fluid Transduction of odontoblasts Recovery – two weeks to six months. GENERAL CONSIDERATIONS: 1.Silicosis Fibrotic pulmonary disease 95% aerosols less than 5 microns
  39. 39. Burs with guide pins :  Enhanced percision  Defined depth  Minimum irregularities of finish line (Quintessence Int 2001;32:191-197) RECENT ADVANCES
  40. 40. TWO STRIPER TECHNOLOGY FASTER CUTTING Natural diamonds on Two striper instruments contain more corners and angles to produce faster cutting. SMOOTH FINISH MARGIN The spiral pattern stops short of the tip to ensure a smooth margin. INCREASED EFFICIENCY Clearance angles in the spiral design provide efficient removal of debris and access for water coolant. (Austenal Quality Dental Products)
  42. 42. LVS SYSTEM
  43. 43. ANGULATED DIAMOND ROTARY CUTTING INSTRUMENTS -Additional method for achieving desirable convergence angles. -To evaluate the amount of convergence angle that has been produced. JPD 2003;90:401-5
  44. 44. STERILIZATION AND INFECTION CONTROLSTERILIZATION AND INFECTION CONTROL Dating back to hippocrates, health care providers declare, “Do no harm”. ADA code of ethics has its primary goal as, “your safety”. CDC(Centre for disease control and prevention) and OSHA(Occupational safety and health administration) have set certain guide lines: 1. Physical barriers: masks, gloves, eye wears, gowns. 2. Use disposable items as much as possible: Disposable drapes, cups, suction tips. Disposable diamond points are also available: -First described by Dr. SIEGEL in 1998 -Minimizes cross contamination risks -Cutting efficiency is comparable to conventional diamond points -Purchase price of disposable diamond points is less as compared to multiuse diamond point .Cost differential is attributed to thinner layer of electroplated metal on disposable diamond points. JADA
  45. 45. 3. Cleaning instruments and equipments that are not disposable. 4. Attempt to identify as many patients as possible who are infectious 5. Use of disinfectant and sterilization procedures: a) Hand pieces- Both high and low speed hand pieces are best autoclaved. Disinfectants such as 0.5% hypochlorite will damage high speed hand pieces. Chemical vapour pressure sterilization recommended for ceramic-bearing hand pieces. Ethylene oxide gas – also used for sterilization of hand pieces. b) Steel burs – dry heat or immersion in cold steriliant for 10 minutes prior to ultrasonic cleaning. Diamond and tungsten carbide burs – disinfectant solution of 0.2 % glutaraldehyde and sodium phenate (sporicidin) for 10 minutes. Follow with cleaning in ultrasonic bath. Then sterilization in autoclave or dry heat sterilization.
  46. 46. CUTTING EFFECTIVENESS OF DIAMOND INSTRUMENTS SUBJECTED TO CYCLIC STERILIZATION METHODS: (JPD 1991 ;66: 721-6) Methods studied: 1.Cold sterilization for 6.75hr in 2% glutaraldehyde(Sporicidin) 2.Chemical vapour (Chemiclave) for 20min at 132 C at 20 psi 3.Steam under pressure (autoclave) for 15min at 121 C and 15 psi 4.Dry heat (Dri-clave) at 170 C for 1 hr Results: 1.The cutting effectiveness of rotary diamond instruments was not influenced by sterilization methods. 2.SEM evaluation made prior to cutting and at the end of 10 cycles of sterilization demonstrated that diamond wear was similar in all groups and that little diamond particle loss occurred in any group.
  47. 47. SUMMARYSUMMARY When we review the history of development of tooth cutting techniques we realize how rapid was the progress from the introduction of the dental engine in 1871 up till now. At present the field of tooth cutting techniques is still in a rapidly changing state of flux. Uptill now there is no one instrument that has been devised that will meet the requirement of each individual dentist.
  48. 48. REFERENCESREFERENCES 1. Philip’s science of dental materials Skinner 2. The science & Art of dental ceramics John W. Mc Lean 3. Restorative dentistry Craig 4. Text book of dental materials Sharmila Hussain 5. Q I. March 2001. Volume 32. Number 3 6. JPD. July 1999. Volume 82. Issue 1 7. Notes on dental materials Wright
  49. 49.