Force of intrusion in orthodontics /certified fixed orthodontic courses by Indian dental academy

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Force of intrusion in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. FORCE OF INTRUSION INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. • INTRUSION? Burstone (1977) - the apical movement of the geometric center of the root (centroid) in respect to the occlusal plane based on the long axis of the tooth. • DEEP OVERBITE? The excessive vertical overlap of the upper anterior teeth over the lower. www.indiandentalacademy.com
  3. 3. • WHY DO WE INTRUDE? - Cl-II and few Cl-I malocclusions manifest deepbite - Causing an extrusion of upper anterior teeth - Leading to a gummy smile www.indiandentalacademy.com
  4. 4. GUMMY SMILE IDEAL SMILE LINE CORRECT INCISOR RELATION INCREASED OVERBITE www.indiandentalacademy.com
  5. 5. PRINCIPLES FOR OBTAINING INTRUSION - Light and constant force - Single point of force application - Sequential intrusion - Good control of anchorage - Analysis of the forces and movements involved in the different biomechanical situations Burstone www.indiandentalacademy.com
  6. 6. IDEAL FORCE REQUIREMENTS FOR INTRUSION - 50gms total against the central incisor - 100gms(0.9n)against the incisal segment in the maxillary arch. Burstone www.indiandentalacademy.com
  7. 7. • This study compares the forces exerted by the various intrusive sectional arch’s on the upper anterior teeth using different wires. www.indiandentalacademy.com
  8. 8. AIMS OF THE STUDY Comparison of stresses exerted by-Utility Arch - 0.016 x 0.022 Elgiloy. -Utility Arch – 0.016 x 0.022 Stainless Steel. -Burstone Intrusion Arch (with coil) - 0.016 x 0.022 Stainless Steel. -Burstone Intrusion Arch (with coil) - 0.016 x 0.022 TMA. -Connecticut Intrusion Arch - 0.016 x 0.022 Nickel Titanium. www.indiandentalacademy.com
  9. 9. On the alveolar bone of maxillary incisor segment of a human skull using ‘strain gauges’ • To compare intrusive forces produced by the same arch wires using an instron machine. www.indiandentalacademy.com
  10. 10. REVIEW LITERATURE • ROBERT RICKETS (1950) - Rickets step down base arch. • CHARLES.R.BURSTONE (1977) - Intrusive arch for placement in the central incisors or four incisors. • MARC.M.VANDERBULCKE et al (1986) - Center of resistance • JAMES.A.McNAMARA (1986) - The utility arch www.indiandentalacademy.com
  11. 11. • BHAVANA SHROFF et al (1995) - Appliance for simultaneous intrusion and retraction of upper anterior teeth. • VARUN KALRA (1998) - K-SIR Arch. • RAVINDRA NANDA et al (1998) - Connecticut intrusion Arch. www.indiandentalacademy.com
  12. 12. MATERIALS AND METHODS • Human skull with all well aligned maxillary teeth and good bone support. • Fitted with a 0.018 slot preadjusted edgewise bracket of roth prescription. www.indiandentalacademy.com
  13. 13. ARMAMENTARIUM www.indiandentalacademy.com
  14. 14. WIRES AND ARCH WIRE FORMS INTRUSIVE ARCHES Burstone intrusion arch Burstone intrusion arch Utility arch ARCH WIRE MATERIAL Stainless steel COMPANY Straight length-unitek TMA Straight length-ormco Elgiloy Utility arch Stainless steel Straight length-american orthodontics Straight length-unitek Connecticut intrusion arch Nickel titanium www.indiandentalacademy.com Preformed-ortho organizers
  15. 15. WIRE AND ARCH WIRE FORMS Burstone Intrusion Arch 0.016”X0.022” TMA Utility Arch 0.016” X 0.022” SS Utility Arch 0.016” X 0.022” Elgiloy Burstone Intrusion Arch 0.016” X 0.022” SS Connecticut Intrusion Arch 0.016” X 0.022” Nickel Titanium www.indiandentalacademy.com
  16. 16. • The template was made - Pressing a softened sheet of wax onto the test jaw containing the full complement of teeth therefore creating indentations on the wax sheet. - The wax was cut and the arch form transferred to a template - All the arch forms were then made around this template. - The connecticut arch was preformed and its length adjusted and modified accordingly. www.indiandentalacademy.com
  17. 17. THE TESTING SYSTEM Two systems were employed 1.Strain gauge 2.Instron testing machine www.indiandentalacademy.com
  18. 18. STRAIN INDICATOR INSTRON MACHINE DIGITAL DISPLAY www.indiandentalacademy.com
  19. 19. STRAIN GAUGE -1mm strain gauge made of 45% nickel and 55% copper -Fixed on to the alveolar bone of each maxillary incisor at its approximate centroid -Strain gauge connected to strain indicator using an electrical wire. -Wheatstone bridge circuit to measure the strains. www.indiandentalacademy.com
  20. 20. -Burstone and connecticut arches placed piggy back on the base arch wire and secured. -Strain meter ensured to check zero before each reading -Procedure repeated for each tooth. -Utility arch was tied directly onto the anterior brackets and readings recorded similarly • Five arch wires in each sample was tested and the result was calculated www.indiandentalacademy.com
  21. 21. • Testing method -The Youngs modulus = stress/strain -The Youngs modulus of alveolar bone = 1.4 x (10)3 kg/mm2 -Therefore 1.4 x (10)3 kg/mm2 = stress/strain - strain = value obtained from the strain indicator for individual teeth when intrusive arch was engaged. - stress was calculated subsequently substituting the values. www.indiandentalacademy.com
  22. 22. • Instron machine(model no.4204) - subjected intrusion arch inserted into the molar tubes accordingly -incisor brackets detached to avoid interference -levels of slots marked -skull positioned to in the desired manner -instron crosshead speed set at 2cm/min or 20mm/min www.indiandentalacademy.com
  23. 23. -A 1mm stainless steel hook for pulling the arch wire secured to the instron -Wire was pulled till level marked at incisors -Five different readings recorded for each intrusion arch. www.indiandentalacademy.com
  24. 24. STRAIN GAUGE IN POSITION STUDY SET-UP www.indiandentalacademy.com
  25. 25. INTRUSIVE FORCES BEING MEASURED USING www.indiandentalacademy.com INSTRON
  26. 26. STRESS VALUES EXERTED BY DIFFERENT ARCHES ON THE ALVEOLAR BONE OF THE INCISOR SEGMENT IN GMS/MM2 GROUP VALUES GROUP-1 CONNECTICUT INTRUSION ARCHNICKEL TITANIUM 56.12 58.04 60.00 51.40 54.28 GROUP-2 BURSTONE INTRUSION ARCH-TMA 78.40 73.60 80.84 75.54 78.40 www.indiandentalacademy.com
  27. 27. 87.52 GROUP-3 90.10 BURSTONE INTRUSION ARCH- STAINLESS STEEL 92.24 92.10 85.54 123.2 GROUP-4 UTILITY ACH-STAINLESS 126.6 123.2 STEEL 128.4 130.42 GROUP5 UTILITY ARCHELGILOY 150.08 153.8 156.8 153.8 150.08 www.indiandentalacademy.com
  28. 28. INTRUSIVE FORCES EXERTED BY DIFFERENT INTRUSIVE ARCHES EVALUATED USING A INSTRON MACHINE GROUP VALUES GROUP-1 CONNECTICUT INTRUSION ARSHNICKEL TITANIUM 35.12 34.96 34.95 34.96 35.00 GROUP-2 BURSTONE INTRUSION ARCH-TMA 59.20 59.45 59.50 59.35 59.50 www.indiandentalacademy.com
  29. 29. GROUP-3 BURSTONE INTRUSION ARCH-STAINLESS STEEL 79.91 80.01 79.35 79.61 80.23 110.00 GROUP-4 UTILITY ARCH-STAILESS 110.01 110.10 STEEL 109.90 110.10 GROUP-5 UTILITY ARCH-ELGILOY www.indiandentalacademy.com 126.10 126.20 125.90 125.80 126.10
  30. 30. • The analysis used for statistically evaluating the five sets of arch wires were– THE STUDENTS ‘T’ TEST – THE ANOVA ANALYSIS www.indiandentalacademy.com
  31. 31. RESULTS Arch forms that showed force in descending order: 1- UTILITY ARCH - Elgiloy (group 5) 2- UTILITY ARCH - Stainless steel(group 4) 3- BURSTONE INTRUSION ARCH - Stainless steel (group 3) 4- BURSTONE INTRUSION ARCH - TMA (group 2) 5- CONNECTICUT INTRUSION ARCH - NiTi (group 1) www.indiandentalacademy.com
  32. 32. STRESS VALUES EXERTED BY DIFFERENT ARCHES ON THE ALVEOLAR BONE 0 – CONNECTICUT INTRUSION ARCH 0 - BURSTONE INTRUSION ARCH – SS 0 – UTILITY ARCH – ELGILOY 0 – BURSTONE INTRUSION ARCH – TMA 0 – UTILITY ARCH - SS www.indiandentalacademy.com
  33. 33. INTRUSIVE FORCES EXERTED BY DIFFERENT ARCHES 0 – CONNECTICUT INTRUSION ARCH 0 - BURSTONE INTRUSION ARCH – SS 0 – UTILITY ARCH – ELGILOY 0 – BURSTONE INTRUSION ARCH – TMA 0 – UTILITY ARCH - SS www.indiandentalacademy.com
  34. 34. CONCLUSION • From this study it is concluded that by listing the force delivered by various intrusive arches , it is in the hands of the orthodontist to select the ideal intrusive arch depending on the needs of individual case and use his or her knowledge of bio-mechanics to get the best of results. www.indiandentalacademy.com
  35. 35. www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

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