Space analysis /certified fixed orthodontic courses by Indian dental academy


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Space analysis /certified fixed orthodontic courses by Indian dental academy

  1. 1. SPACE ANALYSIS INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. INTRODUCTION:  Proper alignment of the teeth requires harmony between the tooth sizes and the space required within the dental arch.  Sometimes the space available is not similar to the space required for the alignment of the teeth.
  3. 3.  It is thus important for the clinician to determine prior to the onset of the orthodontic treatment the space requirements necessary for favorable results.  To accomplish this, a space analysis must be done.
  4. 4. MIXED DENTITION SPACE ANALYSIS  A Mixed Dentition Space Analysis helps one estimate the amount of spacing or crowding which would exist for the patient if all the primary teeth were replaced by their successors the very day the analysis is done, not two or three years later.
  5. 5.  It does not predict the amount of natural decrease in arch perimeter, which may occur during the transitional period without the loss of teeth.
  6. 6. Many mixed dentition space analysis methods have been suggested, all fall into 3 categories :  Those in which the sizes of unerupted cuspids and bicuspids are estimated from measurements of their radiographic images.
  7. 7.  Those in which the sizes of the cuspids and bicuspids are derived from knowledge of the sizes of permanent teeth already erupted in the mouth.  A combination of above approaches.
  8. 8.  In all of the commonly used mixed dentition analysis, the mandibular permanent incisors have been chosen for measuring, since they are erupted into the mouth early in the mixed dentition, they are easily measured accurately and they are directly in the midst of most space management problems.
  9. 9.  The maxillary incisors are not used in any of the predictive procedures since they show too much variability in size and their correlation with other groups of teeth are of low predictive values. Therefore, the lower incisors are measured to predict the sizes of the upper as well as lower cuspid and bicuspid teeth.
  11. 11. NANCE – CAREYS ANALYSIS  In evaluating the available bone structure to accommodate the permanent dentition, it is necessary to make certain calculations in the mixed dentition.
  12. 12.  This method patterned after Nance, is used as a basis for a calculation which takes into account the degree of rotation or displacement of the lower anterior teeth, so that a complete survey and an accurate determination can be made of the amount of space available and required in the entire lower arch.
  13. 13.  The same calculation is applied to secondary dentition which might or might not require removal of dental units in treatment.
  14. 14. METHOD  An .012 brass wire is adapted to the lower mixed dentition model so that one end engages the mesiobuccal line angle of the lower left first permanent molar near the marginal ridge.
  15. 15.  The wire then passes over the buccal cusps of the deciduous molars through their greater diameters, over the normal cuspal position of the cuspids, then over the anterior teeth at ridge centre where the incisal edges of the lower anterior teeth are normally found, then around the same course on the opposite side, ending in the mesiobuccal line angle of the lower right first permanent molar.
  16. 16.
  17. 17.  The wire is cut at this point, measured and recorded.  Then the mesiodistal diameters of lower anterior teeth are measured and their sum taken.
  18. 18.  From measurements made on the casts of a hundred cases of primary and secondary dentitions of the same patient, carey found that a definite relationship exists between the sizes of these teeth and the unerupted cuspids and two premolars, and have deviced a table for quickly making this determination without the aid of x-rays.
  19. 19.      LA + 2(X) + 3.4 = L.D. L.A  Sum of Lower Anterior Teeth (X)  Estimated size of the two premolars and cuspid 3.4  Inevitable mesial drift (1.7 mm) of the first permanent molar on each side following exfoliation of the deciduous molars. L.D.  Linear dimension (Length of the wire)
  20. 20.  If it is smaller by 2.5 mm or less, a lingual arch treatment is justified before loss of the deciduous molars in order to accomplish a satisfactory result in treatment without extraction of premolars.
  21. 21.    This analysis can be applied to the permanent dentition as well. 3.4 mm figure is not included in the formula and measure the actual diameter of the cuspids and premolars or just refer to the table for the (X) value. The variation in linear dimension in the permanent dentition when extraction is indicated will vary from -2.5 to -14.
  22. 22. SIGNIFICANCE :  It is possible to diagnose cases reporting in the mixed dentition with fair degree of accuracy regarding possibilities of treatment with or without extraction of premolars in the permanent dentition.
  23. 23.  Calculations are made from tooth and linear arch dimension to determine whether any retentive type of treatment in the mixed dentition will be successful in obtaining a slight increase in linear dimension of the permanent dentition and thus obviate reduction of tooth structure in hand.
  24. 24. TWEED METHOD  The space required for the four mandibular incisors were measured at their greatest mesiodistal crown diameter by means of a sliding Boley gauge, with pointed beaks.  The values for unerupted canines and premolars were obtained by measuring their greatest mesiodistal crown diameter of their images on the periapical radiograph.
  25. 25.
  26. 26.
  27. 27.       To reduces radiographic enlargement, the formula recommended by Huckaba was used in all radiographic measurement : X = (y) (x’) Y’ X  Estimated size of the permanent tooth X’  Radiographic size of the permanent teeth Y  The size of the primary mandibular second molar on the cast. Y’  the radiographic size of the primary molar.
  28. 28.  The values obtained for the mandibular incisors on the cast and those for the canines and premolars on the radiograph were added to provide the space required.
  29. 29.  The space available was obtained by extending a brass wire from the mesiobuccal cusp of the first permanent molar on one side to the mesiobuccal of the molar on the opposite side, passing through the buccal cusps and incisal edges of the remaining teeth.
  30. 30.
  31. 31.  The difference in the values obtained for the space required and space available was the amount of the discrepancy.  An assessment of the relations between the axial inclination of the mandibular incisors and the basal bone was made on a tracing of the lateral cephalogram.
  32. 32.
  33. 33.      The amount of alveodental protrusion or retrusion was assessed and incorporated into the mixed dentition analysis. Tweed Foundation Research has established the following relationship : When the FMA is between 21° and 29°, the FMIA should be 68° When the FMA is 30° or greater, the FMIA should be 65° When FMA is 20° or less, the IMPA should not exceed 92°
  34. 34.   If for a specific FMA (30°) the FMIA (49°) did not correspond, an objective line was traced to form the required FMIA (65 °). Then the distance between this objective line and the line that passed through the actual inclination of the mandibular incisors was measured on the occlusal plane with pointed calipers to the nearest 0.1 mm (6 mm).
  35. 35.  This figure was multiplied by ‘2’ to include right and left sides (12 mm).  The total was the cephalometric correction which was then added to the difference between the space required and space available to yield total discrepancy.
  36. 36. TOTAL SPACE ANALYSIS IN MIXED DENTITION ( Leven Merrifield 1988 )   The various mixed dentition analysis demonstrate the discrepancy only and do not indicate the exact area where the discrepancy occurs. In many instances, the problem is confined to one area, it is desirable to know the area affected. The total space analysis provides this precise information.
  37. 37.   This method divides the lower dental arch into three areas – ANTERIOR, MIDDLE AND POSTERIOR – to analyse the space requirement in the lower arch. Measurements from the study casts and cephalograms are used in this analysis. The discrepancies for each area has to be calculated and the resultant values are added together to yield the discrepancy of the arch.
  38. 38.    ANTERIOR AREA: Space Required : Measure the width of the mandibular incisors on the casts and the width of the cuspids from the radiographs. Cephalometric corrections for the incisor positioning is calculated according to the Tweed’s method. The chin / lip soft tissue profile line related to the Frankfort horizontal plane quantifies facial balance.
  39. 39.
  40. 40.  It has a normal range of 70° - 80°. The ideal value is 75° to 78°, depending in the age and gender.  It is more indicative of soft tissue profile than the FMIA and is responsive to maxillary incisor position.
  41. 41.  Upper lip thickness is measured from the vermilion border of the lip to the greatest curvature of the labial surface of the central incisors. The total chin thickness is measured from the soft tissue chin to the N.B line.
  42. 42.
  43. 43.  If the lip thickness is greater than chin thickness, the difference is multiplied by ‘2’ and added to the space required.  If it is less than or equal to chin thickness no soft tissue modification is necessary.
  44. 44.  Space Available : Measured by using a brass wire from the mesiobuccal line angle of first primary molar of one side to the other.
  45. 45. MIDDLE AREA  Measure the mesiodistal width of the first permanent molars on the cast and measure the width of the unerupted premolars from the radiographs.  Curve of occlusion
  46. 46.
  47. 47.  A flat object is placed on the occlusal surface of the mandibular teeth contacting the incisors and the first permanent molars. The deepest point between this flat surface and the occlusal surface of primary molars was measured on both sides.
  48. 48.
  49. 49.  The following formula was applied to know the space required for leveling the curve of occlusion. Depth on right side + Depth of left side + 0.5mm 2  Space available : From the mesiobuccal line angle of first primary molar to the distobuccal line angle of first permanent molar on either side.
  50. 50.   POSTERIOR AREA: Space Required : Mesiodistal width of second and third molars is obtained from the radiographs as they might be unerupted. If these molars are not visible on the radiographs, ‘Wheelers’ method is used for calculation: X = Y – X’ Y’
  51. 51.  X  estimated value of third molars in the individual patient.  Y  Actual size of permanent mandibular first molar.  X’  Wheelers value of third molars  Y’  Wheelers value of first molars
  52. 52. Space Available :  The amount of space available consisted of space presently available on the casts and the estimated increase. a. Space presently available: This is obtained by measuring the distance on the occlusal plane tangent to the distal surface of first permanent molars to the anterior border of the ramus on a lateral cephalogram.
  53. 53.
  54. 54.   b. Estimated increase or prediction : The estimated increase is 3 mm / year i.e. 1.5 mm on either side until 14 years of age in girls and 16 years in boys. The age of the patient is subtracted from 14 or 16 according to the sex of the patient and is multiplied by 3 to obtain the estimated increase.
  55. 55.  TOTAL SPACE DEFICIT : The total discrepancy is arrived at by comparing the space required and space available in the anterior middle and posterior areas. Thus this analysis tells us precisely where the discrepancy is present, i.e. in the anterior, middle or the posterior areas.
  56. 56. MOYER’S MIXED DENTITION ANALYSIS ( Moyers 1967 ) In this analysis size of the cuspids and premolars are derived from the knowledge of the size of permanent teeth already erupted in the mouth. The lower incisors are measured to predict the size of upper as well as lower posterior teeth.
  57. 57. 1) Measure with the Boley gauge, the greatest mesiodistal width of each of the four mandibular incisors. Record these values on the Mixed Dentition Analysis form. 2) Determine the amount of space needed for alignment of the incisors. Set the gauge to a value equal to the sum of the widths of the left central incisor and left lateral incisor.
  58. 58.
  59. 59. 3) Compute the amount of space available after incisor alignment by measuring the distance from the point marked in the line of the arch (i.e. from the distal surface of the lateral incisor in a well formed anterior arch form) to the mesial surface of the first permanent molar. This distance is the space available for the permanent cuspids and bicuspids.
  60. 60. 4) Predict the size of the combined widths of the mandibular cuspids and bicuspids. Moyer uses 75% of probability rather than 50%. Although the values distribute normally towards spacing and crowding. Crowding is a much more serious clinical problem and the 75% predictive values thus protects the clinician of the safe side.
  61. 61. 5) Compute the amount of space left in the arch for molar adjustment by subtracting the estimated cuspid and bicuspid size from the measured space available in the arch after alignment of the incisors. Record these values for each side.
  62. 62. MERITS  It has minimal systematic error and the range of such error is known.  It can be done with equal reliability by the beginner and the expert, as it does not pressure sophisticated clinical judgement.  It is not time consuming.
  63. 63.  It requires no special equipment or radiographic projections.  Although best done on dental casts, it can be done with reasonable accuracy in the mouth.  It can be used for both dental arches.
  64. 64. DEMERIT  Moyer’s Mixed Dentition Analysis over predicts the tooth size of the unerupted canines and premolars, hence it may convert a borderline case into an extraction case.
  65. 65. TANAKA AND JOHNSION METHOD : Marvin M. Tanaka Lysle E. Johnston 1974.   Tanaka and Johnson developed another way to use the width of the lower incisors to predict the sizes of the unerupted canines and premolars. This method has good accuracy despite a small bias toward overestimating the size of unerupted tooth.
  66. 66. TANAKA AND JOHNSION Prediction Values   One half the mesiodistal width of four lower incisors + 10.5 = Estimated width of mandibular canine and premolar in one quadrant.  One half the mesiodistal width of Four lower incisors + 11.0 = Estimated width of maxillary canine and premolars in one quadrant.
  67. 67. HUCKABA’S METHOD OF PREDICTION : George W. Huckaba 1964.   Based on the measurement of teeth on radiograph. With any type of radiograph it is necessary to compensate for enlargement of the radiographic image. This can be done by measuring an object that can be seen both in the radiograph and on the cast, using a primary molar tooth (Muckaba).
  68. 68. A simple proportional relationship can be set up :  True width of primary Molar = Apparent width of primary molar  True width of unerupted premolar = Apparent width of unerupted premolar 
  69. 69.  Accuracy is fair to good depending on the quality of radiographs and their positions in the arch. The technique can be used in maxillary and mandibular arches for all Ethnic group.
  70. 70. HIXON AND OLDFATHER PREDICTION ( 1957 )  This method of prediction uses both the radiographs and prediction tables. Since the major problem with using radiographic images comes in evaluating the canine teeth, it would seem reasonable to use the size of permanent incisors measured from the casts and the size of unerupted premolars measured from the periapical films to predict the size of unerupted canines.
  71. 71.   Mandibular dental casts of 76 subject from Iowa facial growth study, 7 ½ to 11 years of age were measured. X-ray films of unerupted premolars were taken The best estimate was obtained when mesiodistal width of left central and lateral incisors were combined with X-ray measurement of unerupted first and second premolars of the same side.
  72. 72.  From the prediction table, the predicted size of the unerupted canines and premolars are found against the measured value. This method is restricted to the mandible.
  73. 73. PREDICTION TABLE measured value Estimated tooth size 23 18.4 24 19.0 25 19.7 26 20.3 27 21.0 28 21.6 29 30 22.3 22.9
  74. 74. REVISED HIXON AND OLDFATHER METHOD ( STALEY AND KERBER, Robert N. Staley 1980 )  Staley and Kerber developed a graph from IOWA growth data which allows canine width to be read directly from the sum of incisor and premolars width.  This method can be used only for the mandibular arch.
  75. 75.  Measurements were taken to the nearest 0.05 mm with Helios dial caliper. All computations were performed by a computer.
  76. 76. INTERLATERAL INCISOR WIDTH ANALYSIS ( Motokawa, Ozaki, Soejina, Yoshida, 1987 )  A method of mixed dentition analysis in the mandible.  The measurement between the distal surfaces of the mandibular permanent lateral incisors is approx. equal to that of combined widths of mandibular permanent canine and first and second premolars.
  77. 77. MIXED DENTITION ANALYSIS FOR ASIANAMERICANS Lee-Chan, Jacobson, Chwa, Jacobson 1998  The most commonly used prediction method of Tanaka and Johnston is based on data from a sample of children of Northern European descent. The accuracy of this method when applied to a different ethnic population is
  78. 78.   Used 201 dental plaster casts of AsiaPacific – American subjects, all under the age of 21 years. The actual measurements were compared with the prediction values derived from the Tanaka and Johnston equations and significant differences were found.
  79. 79.  The data illustrate the limitations of the Tanaka and Johnston method when applied to a sample population of other than European descent. From this data, two linear regression equations were developed for tooth size prediction in Asian - American children.
  80. 80. The Tanaka and Johnston regression equation are as follows: Y = 10.5 + 0.5 (X) for mandibular canine – premolar segment Y = 11.0 + 0.5 (X) For maxillary canine - premolar segment  Where Y  the estimate of the sum of the mesiodistal width of the unerupted canine and premolar on either side.  X  the sum of the mesiodistal width of the four mandibular incisors.
  81. 81.  The equation is most accurate when the widths of mandibular canines and premolars are in the range of 21.0 to 23.0 mm;  and when the widths of maxillary canine and premolars are in the range of 22.0 to 24.0 mm.
  82. 82.      Specifically, different regression equations were derived and simplified for the size prediction of maxillary and mandibular canines and premolars in an Asian American population : Maxillary : Y = 8.2 + 0.6 (X) Mandibular : Y = 7.5 + 0.6 (X) X = Mesiodistal widths of the four mandibular incisors in mm. Y = Mesiodistal width of the canines and premolars in one quadrant in mm.
  83. 83. Limitations of the mixed space analyses   A problem arises when considering the space left for molar adjustments. If the value in the chart is negative , i.e, the predicted sizes of the cuspid and bicuspid teeth is greater than the space available after the alignment of the incisors, then crowding will occur in the arch even without any forward molar adjustment.
  84. 84.  When the first permanent molar teeth are in an end-to-end relationship, approximately 3.5 mm of space is required to convert the occlusion to class I molar relationship.  This 3.5mm might be acquired without orthodontic intervention in any of the three ways:
  85. 85.    3.5mm more late mesial shift of the mandibular first permanent molar than that of the maxillary first permanent molar; At least 3.5mm more forward growth of the mandible than of the maxilla; some combination of dental adjustment and differential skeletal growth.
  86. 86.  Often in the mixed dentition there is indeed a flat occlusal plane, but many times the curve of spee is exaggerated or complicated.  Finally the clinician should recognize that any mixed dentition analysis is simply a guide to a treatment decision.
  87. 87. SPACE ANALYSIS IN PERMANENT DENTITION    Two practical ways exist to analyze the spacing requirements of the permanent dentition. First way involves directly the dental casts themselves. Second method involves computer digitizing and measuring the teeth and the dental arches from a two dimensional occlusal image.
  88. 88.  Regardless of which method is used, the space required and space available values must be calculated.  The space available can be ascertained by measuring the arch perimeter from first molar to first molar.
  89. 89.    Divide the dental arch into 4 segments of straight line through the contact points of the posterior teeth and the incisal edges of the anterior teeth. Linear measurements: two posterior arch segments and two anterior arch segments. The total represents the space available for alignment.
  90. 90.
  91. 91.  A second way to measure the space available is to bend a piece of brass wire through the contact points of the posterior teeth and the incisal edges of the anterior teeth, on the occlusal plane of the dental casts. This wire can be straightened out measured
  92. 92.
  93. 93. CAREY’S ANALYSIS This analysis helps to determine the extent of the discrepancy.  It is performed on the lower cast.  Same analysis on the upper cast is called Arch Perimeter Analysis. Determination of tooth material:  The mesio-distal width of the teeth anterior to the first molars (second premolar to second premolar) is measured and summed up. 
  94. 94. Determination of arch length:  The arch length anterior to the first permanent molar is measured using a soft brass wire. The wire is placed contacting the mesial surface of the first permanent molar of one side and is paced over the buccal cusps of the premolars and along the anteriors and is continued on the opposite side upto the mesial surface of the opposite first permanent molar.
  95. 95.    In case of proclined anteriors, the wire is passed along the cingulum of the anterior teeth. If the anterior teeth are retroclined, the brass wire in the anterior segment passes labial to the teeth. If the anterior teeth are well aligned the wire passes over the incisal edge of anteriors.
  96. 96. Determination of the discrepancy:  The discrepancy refers to the difference between the arch length and tooth material. a) If the discrepancy is 0-2.5 mm, it indicates minimal tooth material excess. Proximal stripping can be carried out to reduce the tooth material.
  97. 97. b) If the discrepancy is between 2.5-5mm, it indicates the need to extract the second premolars. c) A discrepancy of more than 5mm indicates the need to extract the first premolars.
  98. 98. The Royal London Space Planning  The Royal London Space Planning has evolved since 1985 as the part of the postgraduate training program at the Royal London Hospital.  The theoretical basis is derived from the work of Andrews, who states that a space discrepancy will arise if the teeth do not conform to his “six keys to normal occlusion”.
  99. 99.   The purpose of the Royal London Space Planning is to quantify the space required in each dental arch to attain the treatment objectives in the permanent or late mixed dentition and to the space implication of treatment mechanics. 2 ways:- assessment of space requirement and other is an assessment of any additional space to be created.
  100. 100. Six specific aspects of the occlusion are considered for which any change has an effect on the space required. Space requirements : Crowding and spacing: measure in relation to the line of arch that reflects the majority of teeth. Level curve of spee : assess the depth of curve from premolar cusps to a flat plane on distal cusps of first molar and incisors. Arch width change : allow 0.5mm space for each mm posterior arch width change. 
  101. 101. Incisor A/P change : Allow 2mm space for each mm change.  Angulation change : Applies only to maxillary incisors.  Inclination change. Space creation :  Tooth reduction.  Tooth enlargement.  Extractions.  Space opening.  Differential growth. 
  102. 102.
  103. 103.
  104. 104. LIMITATIONS OF PERMANENT DENTITION SPACE ANALYSES    Situations can occur which could compromise the accuracy of the previously described permanent dentition space analyses. Dentally, if the angulation of the incisors is excessively proclined, it will impart the appearance of alignment disharmonies. Proclined incisors will seem to diminish the dental crowding while retroclined incisors enhance the crowding.
  105. 105.  The prudent clinician will note any deviations in incisor position, either cephalometrically or by clinical exam, and weight these factors in when using the space analysis.
  106. 106.   Skeletally, in non-growing individuals, the arch perimeter or space available measurements would be expected to change very little. Unfortunately, in children with disproportionate skeletal jaw growth patterns teeth can shift either anteriorly or posteriorly in response. For these individuals, space analysis will be of great need, but of lesser accuracy.
  107. 107. REFERENCES    Michael L. Riolo and James K. Avery and Manish Valiathan; Essentials For Orthodontic Practice: 2003. Thomas M Graber, Robert Vanarsdall : Orthodontics-current principles and techniques; 4th edition 2004 page 439 450. Moyers R. E : Hand book of orthodontics, 4th edition, 1988 page 221 – 248.
  108. 108.    Murray L. Ballard and Wendell. L. Wylie : Mixed dentition case analysis. Estimating size of unerupted permanent teeth. AJO 1947 page 754 – 759. HUCKABA G W : Arch size analysis and tooth size prediction. Dent clin North Am 1964; 11: 431 – 40. Tanaka MM, Johnson; The prediction of the size of unerupted canine and premolars in a contemporary othodontic population. Journal Am Dent Assoc 1974; 88: 798 – 801.
  109. 109.    Hixon E H, Old father R E : Estimation of the size of unerupted cuspid and bicuspid teeth, Angle Othodontics 1958; 28: 236 – 40. Stanly RN, Kerber PE : A revision of the Hixon and old father mixed-dentition prediction method, AJO 1980; 78: 296 – 30. Motokawa, Ozaki, Soejima, Yoshida: A method of mixed dentition analysis in the mandible, Journal of Dental for children 1987 March-=April : page 114-118.
  110. 110.    Lee-chan, Chwa, Jacobson : Mixed dentition analysis for Asian-americans AJO-DO March 1998 ; 113: 293 – 299. Ursus R. Schirmer, and William A. Wiltshire ; Orthodontic probability tables for black patients of African descent: AJO-DO 1997; 112: 545 – 51. Diagne, Ibrahima Ngom and Khadin M bow: Mixed dentition analysis in a sengalese population AJO-DO August 2003, vol 124 : 178 – 183.
  111. 111. Gerald Z. Wright, and David B. Kennedy: Space Control in the primary and mixed dentitions, Dental Clinics of North America, october 1978; vol 22: page 579 -99.  Robert H. Kirschen, Elizabeth A. O’Higgins, and Robert T. Lee: The Royal London Space Planning: An integration of space analysis and treatment planning. Part I : Assessing the space required to meet treatment objectives. Part II : The effect of other treatment procedures on space. AJO-DO october 2000, vol118. page 448 – 456. 
  112. 112.   Dr. Ashima Valiathan, Dr. Snehalatha Oberoi : Dental Arch Form, kerala Dental Joural vol. 19, (2) , page 39 -42. Ashima Valiathan, Prasad, Randhawa; Mixed Dentition Analysis; JICD vol. 38; 1996.
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