Methods of studying growth /certified fixed orthodontic courses by Indian dental academy


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Methods of studying growth /certified fixed orthodontic courses by Indian dental academy

  1. 1. Methods of studying growth INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. Introduction: Study of man’s development is not always done by studying man himself It is useful that basic principles of development are common to many living organisms since all of man’s development is not accessible to ready study by experimentation . different approaches have been utilized for the study of both normal and abnormal growth. Each has its own limitations.
  3. 3. TYPES OF GROWTH DATA Opinions Observations Ratings and rankings
  4. 4. 1.OPINION a) crudest method b)considered as a calculated guess based on one’s experience. c) very unscientific and should be avoided when possible. For eg. – One may be able to guess which one of the two siblings may be taller by assessing their previous growth.
  5. 5. 2.) Observations: useful for studying all or none phenomenon. For example – in cursory visual examination of 67 Eskimo children ranging between Class II malocclusion was observed. 3) Ratings and Rankings: Rating make use of comparisons with conventional scales or classification normal values ranges between two extreme ends, the average of which is considered as a
  6. 6. Each individual be compared with these norms and rated accordingly. For eg. – This boy is shorter (as compared to the average height of the boys in that particular region of his age). Ranking :method of arranging the data in an orderly sequences according to its value. For eg – The ranks of the children was determined on the basis of their performance in the annual examination.
  7. 7. METHODS OF GATHERYING GROWTH DATA A) LONGITUDINAL: Measurements made of same person/group at regular intervals time are longitudinal measurement. These are thus long term studies. Advantages a) Variability in development among individuals within the group is put in proper perspective.
  8. 8. b)The specific development pattern of an individual can be studied, permitting serial comparisons c)Temporary problems in sampling are smoothed out with time and an unusual event or mistake is more easily seen and corrections made. Disadvantages a) Time consuming b)Expense c)Attrition. d)Averaging
  9. 9. B) Cross Sectional: Measurement made of different individuals or different samples and studied at different periods are cross sectional measurements. Thus, one may measure a group of 7yr. old boys and on the same day, at the same school, measure a group of 8yr.old boys. Changes between 7& 8 yrs of age in boys at that school are thus assumed after study of the data obtained.
  10. 10. Advantages 1. quicker 2. less costly 3. statistical treatment of the data - made easier. 4. it allows repeating of studies more readily, in case of any flaw. 5. used for cadavers skeleton and archeological data.
  11. 11. Disadvantages It must always be assumed that the group being measured and compared are similar. Cross sectional group are averages, tend to obscure individual variations.
  12. 12. C) Overlapping or semilongitudinal data: Longitudinal and cross sectional methods combined to seek the advantages of each. In this way one might compress 15yrs of study into 3yrs of gathering data, each sub sample including children studied for the same member of years but started at different ages.
  13. 13. EVALUATION OF GROWTH DATA I. Quantitative approach: A) Direct growth measurementDirect data are derived from measurements taken on the living person or cadaver by means of calipers, scales, measuring tapes, and other measuring devices.various approaches are
  14. 14. a) Craniometry: Craniometry based on measurements of skulls found among human skeletal remains. From such skeletal material it has been possible to piece together a great deal of knowledge about extinct populations and to get some idea of their pattern of growth by comparing one skull with another.
  15. 15. advantage : that rather precise measurements can be made on dry skulls disadvantage : that by necessity, all these growth data must be cross sectional. b) Anthropometry: In this technique,various landmarks are est in studies of dry skulls -measured in living indiv. by using soft tissue points overlying these bony landmarks
  16. 16. . For eg, it is possible to measure the length of the cranium from a point at the bridge of the nose to a point at the greatest convexity of the rear of the skull. This measurement can be made on either a dried skull or a living individual, but results would be different because of the soft tissue thickness overlying both landmarks.
  17. 17. Advantages: it is possible to follow the growth of an individual directly, same measurements repeatedly different times. made at This produces longitudinal data repeated measures of the same individual.
  18. 18. B. Indirect growth measurements: Indirect growth measurements are those taken from images or reproductions of the actual person. For example, measurements made from - photographs, -dental casts, -cephalograms -skeletal maturity indicators
  19. 19. a)Cephalometric Radiology: •Cephalometric Radiology is of importance not only in the study of growth but also in clinical evaluation of orthodontic patients. •There is precise control of magnification. Advantages: 1.This approach can combine the advantage of craniometry and anthropometry. It allows a direct measurement of bony skeletal dimensions, since the bone can be seen through soft tissue covering in a radiograph.
  20. 20. 2. But it also allows the same individual to be followed over time. Therefore longitudinal study possible their serial cephs. The disadvantages of a ceph: 1. Metric radiograph is that it produces a two dimensional representation of a three dimensional structure 2. Magnification errors . 3. X ray radiation exposure
  21. 21. 2)Skeletal maturity indicators: Because of individual variation, physiological and anatomical maturity cannot be accurately assessed by age alone Other parameters, such as growth velocity, secondary sex changes, dental development, and skeletal ossification, have proven of more value
  23. 23. A)Hand wrist radiographs: The underlying premise is that the osseous changes seen in the hand and wrist are indicators of more general skeletal changes. The system uses only four stages of bone maturation ,all found on six anatomical sites located on the -Thumb -Third finger -Fifth finger -Radius
  24. 24.
  25. 25. The sequence of the four ossification stages progresses through: epiphyseal widening on selected phalanges the ossification of the adductor sesamoid of the thumb the ‘capping’ of selected epiphysis over their diaphysis , the fusion of selected epiphysis and diaphysis
  26. 26.
  27. 27. Skeletal Maturity Indicators (FISHMAN) Width of epiphysis as wide as diaphysis 1.Third finger – proximal phalanx 2.Third finger – middle phalanx 3.Fifth finger - middle phalanx Ossification 4.Adductor sesamoid of thumb
  28. 28. Capping of epiphysis 5.Third finger – distal phalanx 6.Third finger – middle phalanx 7.Fifth finger - middle phalanx Fusion of epiphysis and diaphysis 8.Third finger – distal phalanx 9.Third finger – proximal phalanx 10.Third finger – middle phalanx 11. radius
  29. 29.
  30. 30.
  31. 31. EVALUATION For both the maxilla and mandible measurements, acceleration in growth velocity occurred between skeletal maturation levels SMI 6 and 7, followed by a deceleration until level 9. Mandible and maxilla reached maximum growth rate at SMI level 7 in males and at SMI 6 in females
  32. 32. Percentage of growth completed At SMI level 6, the values representing height, maxilla and mandible all showed achievement of approximately 50% of adolescent growth . as growth velocity decreased during the later part of adolescence, the maxilla and mandible tended to lag behind skeletal growth (taken from AO vol 52 no. 52 april, 1982)
  33. 33. B) MID PALATAL SUTURE The purpose of this study was to determine whether a positive correlation exists between adolescent maturational development and the approximation of the mid palatal suture. The mid palatal suture is formed by three parts .these include -Interpremaxillary -Maxillary -Interpalatine
  34. 34. The following key landmarks and planes were identified : •Point A – most ant. point of the premaxilla •Point B – most post. point on the posterior wall of incisive foramen •Point P – point tangent to a line connecting the posterior walls of the greater palatine foramens
  35. 35. Key landmarks on midpalatal suture
  36. 36. RESULTS Stages of ossification of the midpalatal suture were compared with the fishman’s standards of skeletal maturation indicators Very little mid palatal approx. existed during SMI 1 – 2 At SMI 11 mid palatal suture is only approx. half the suture distance
  37. 37. Very large increases in appr. from SMI 8 – 11 At same SMI stages posterior portion demonstrated larger approximation Maturational development is related to mid palatal fusion in ways that can provide information to better time maxillary expansion It is best to accomplish this before SMI 9 and ideal time to initiate it is between SMI 1 – 4 (taken from AJO vol 105, no. 3 march 1994).
  38. 38. The Cervical Vertebrae as Maturational Indicators To avoid taking an additional x-ray, some researchers have sought to relate maturation with dental and skeletal features other than the bones in the hand and wrist. In 1972, Lamparski concluded that the cervical vertebrae, as seen on routine lateral ceph, were as statistically and clinically reliable in assessing skeletal age as the hand-wrist technique.
  39. 39. Hassel and Farman developed modification of Lamparski's criteria, which assesses maturational changes on the second, third, and fourth cervical vertebrae. Six distinct stages of growth can be related to the SMI developed by Fishman:
  40. 40. Initiation (SMI 1 and 2). The vertebrae are wedge-shaped superior vertebral borders tapering from posterior to anterior. 80 to 100 % of adolescent growth can be anticipated at this stage
  41. 41. Acceleration (SMI 3 and 4). Growth acceleration begins 65-85% of adolescent growth be anticipated. Concavities develop on the inferior borders of C2 , C3. The bodies of C3 , C4 nearly rectangular inferior border of C4 is flat.
  42. 42. Transition (SMI 5 and 6). Adolescent growth accelerates toward peak velocity 25-65% of adolescent growth anticipated. Distinct concavities develop on the inferior borders of C2 and C3. A concavity begins to develop on the inferior border of C4 bodies of C3 and C4 are rectangular.
  43. 43. Deceleration (SMI 7 and 8). Only 10-25% of adolescent growth remains. Clear concavities seen on the inferior borders of C2, C3, and C4 the bodies of C3 and C4 nearly square.
  44. 44. Maturation (SMI 9 and 10). Final maturation takes place at this stage only 5-10% of adolescent growth can be anticipated. Accentuated cavities are seen on the inferior borders of C2, C3, and C4, bodies of C3 and C4 are nearly square.
  45. 45. Completion (SMI 11). Little to no adolescent growth is expected Deep concavities seen on the inferior borders of C2, C3, and C4 vertebral bodies are more vertical than horizontal.
  46. 46. FRONTAL SINUS It was found that the frontal sinus dev. showed a growth rhythm similar to body height development, with a well-defined pubertal peak. SOMATIC MATURITY PREDICTION To use the prediction of somatic maturity stage on the basis of the analysis of the frontal sinus growth velocity, the following findings are pertinent.
  47. 47. Frontal sinus growth shows a well-defined pubertal peak (Sp), which on the average, occurs 1.4 years after the pubertal body height peak (Bp) . In male subjects, the average age at frontal sinus peak is 15.1 years. In a l-year observation interval, a peak growth velocity in the frontal sinus of at least 1.3 mm/yr. is
  48. 48. attained by 84% of the subjects In a 2-year observation interval, a peak growth velocity in the frontal sinus of at least 1.2 mm/yr. is attained by 70% of the subjects (Taken from the AJO-DO on CD-ROM (Copyright © 1997 AJO-DO), Volume 1996 Nov (476 - 482): Frontal sinus development as an indicator for somatic maturity at puberty)
  49. 49. C) Derived Data: obtained by comparing atleast two other measurements for eg. when we say that a persons mandible grew 2mm between ages 7 & 8, the 2mm have not actually been measured rather, the mandibular length at 7yrs has been subtracted from the mandibular length at 8yrs. the increment thus derived is assumed to represent growth.
  50. 50. Experimental Approach A) Bimetric Tests: They are used in which physical characteristics such as weight, ht. skeletal nature and ossification are measured and compared with standards based upon the examination of large no. of healthy subjects.
  51. 51. B) Vital Staining: Vital staining is a technique in which dyes that stain mineralizing tissues are injected into an animal. These dyes remain in the bones and teeth This method was originated by the great English anatomist John Hunter in the 18 C . He discovered that the active agent was a dye called alizarin, which still is used for vital staining studies.
  52. 52. Alizarin reacts strongly with calcium at sites where bone calcification is occurring. Since these are the sites of active skeletal growth, the dye marks the locations at which active growth was occurring when it was injected. Bone remodels rapidly, and areas from which bone is being removed also can be identified by the fact that vital stained material has been removed from these locations.
  53. 53. Antibiotic tetracycline is also used as vital bone markers Other dyes used are – (i) Acid alizarin blue (ii) Trypon blue (iii) Procion
  54. 54. C) Radioactive tracers: Radioactivity labeled metabolite becomes incorporated into the tissues as a sort of vital stain . The location is detected by the weak radioactivity given off at the site when the material was incorporated.
  55. 55. The gamma emitting isotope 99m Tc (TECHNECIUM) can be used to detect areas of rapid bone growth in humans, but these images are more useful in diagnosis of localized growth problems than for studies of growth patterns. It is particularly of importance in study of condylar hyperplasia
  56. 56. D) Molecular genetics: Rapid advances in molecular genetics are providing new information about growth and its control. For example – the whole family of transforming growth factor beta genes now are known to be important in regulating cell growth and organ development.
  57. 57. . Definition Boucher E)IMPLANTS (Implant) :As defined by ‘Implants are alloplastic devices which are surgically inserted into or onto jaw bone’.
  58. 58. stable reference points are needed for accurate assessment of longitudinal growth changes though some relatively stable bony land marks are used as a reference but till today implants are the best means of reference points for studying the longitudinal growth studies . Implant were first used by Bjork and Skeiller for studying growth changes.
  59. 59. It involves implanting small bits of biologically inert Tantalum alloy in certain areas of maxilla and mandible to study growth of skull. These are around 1.5mm in length ,and 0.5mm in diameter.
  60. 60. SITES OF IMPLANT PLACEMENT Maxilla: Hard Palate behind deciduous canines. Below the anterior nasal spine. 2 implants on either side of zygomatic process of maxilla. Border between hard palate & alveolar process medial to the first molar.
  61. 61.
  62. 62. Mandible: Anterior aspect of symphysis, in the midline below the root tips. 2 pins on the right side of the mandibular body. One under the first premolar & the other below the second premolar or first molar. One pin on the external aspect of right ramus in level with the occlusal surface of molars.
  63. 63.
  64. 64. Bjork 1969 presented a survey of experience with the implant method in the study of facial growth ,with particular emphasis on prediction of mandibular growth rotation. The three methods discussed were: Longitudinal Method Metric Method Structural Method
  65. 65. 1. Longitudinal It consists of following the course of development by annual X-ray cephalograms. Shown to be of limited use for this purpose, as the remodeling process at the lower border of the mandible to a large extent masks the actual rotation.
  66. 66. 2) Metric Method Aims at prediction based on a metric description of the facial morphology at a single stage . Predicting the intensity or direction of subsequent development from size or shape at childhood was not feasible with any cephalometric analysis
  67. 67. 3) Structural method This method was thence described by which it may be possible to predict, from a single cephalogram ,the course of rotation, where this feature is marked. This method is based on information gained from implant studies of the remodeling process of the mandible during growth.
  68. 68. Implant radiography: inert metal pins are placed in bones anywhere in the skeleton including face and jaws. These metal pins are well tolerated by the skeleton and become permanently incorporated into the bone without causing any problems. If metallic implants are placed in the jaws, a considerable increase in accuracy of a longitudinal ceph. analysis of growth pattern can be achieved.
  69. 69. method of study developed by. Arne Bjork and Coworkens at the Royal Dental College in copen-hugan Denmark . Superimposing ceph. radiographs on the implanted pins allows precise observation of both changes in the external contours of individual bones. Precise evaluation of dentofacial growth in humans still is done best by implant radiography
  70. 70. Various Growth Studies Among the main resources of the craniofacial research community are the collections of longitudinal growth records that were accumulated at considerable economic and human cost by dedicated investigators
  71. 71. 1.The Broadbent Bolton Growth Study it consists of mixed longitudinal records plus single visit data sets for a total of 5700 subjects. About 15% of these subjects have been seen 10 times or more, but 47% have been seen only once. Thus there are more than 850 longitudinal record sets. In addition to lateral head films, posteroanterior films (PA), and hand-wrist films are available
  72. 72. . The study casts are trimmed (Kerr compound bites), and there are height and weight records The lateral and PA films have all been obtained using the Broadbent Bolton cephalostat The records were gathered under the direction of B. Holly Broadbent, Sr., and the present director is B. H. Broadbent, Jr.
  73. 73. Importance The Broadbent Bolton collection has played a major role in the development of cephalometric techniques and orthodontic treatment standards, and in recent years has been the basis of an important longitudinal study of craniofacial aging
  74. 74. 2) The Burlington Growth Study The Burlington Growth Study is located at the Burlington, Ontario Orthodontic Research Centre at the University of Toronto. Its various longitudinal samples contain 1632 subjects in all
  75. 75. All samples are of the "diminishing" longitudinal type The records for the serial experimental and control subjects include : a) lateral head films (taken at rest, in occlusion, and with the mouth open), b) PA, c) 45° oblique d) hand-wrist films, e) photographs, f) study casts (with wax
  76. 76. g) height, weight, written treatment records (for the annual series only), h) and some medical histories. The enlargement factor is 9.8% at the midsagittal plane for all lateral films The records were gathered under the direction of Frank Popovich
  77. 77. 3) The lowa Child Welfare Study The Iowa Facial Growth Study is of the diminishing longitudinal type. The sample began with 20 male and 15 female 4-year-old subjects. These sample sizes diminish toward age 17 years; exact figures are not available for each age. Most subjects were recalled at age 25 years.
  78. 78. In addition to lateral head films, PA films are available. The records were gathered by H. V. Meredith who pricked the principal landmarks on each film Orthodontically treated subjects are not included in the series. • (Taken from the AJO-DO on CD-ROM (Copyright © 1997 AJO-DO), Volume 1993 Jun (545 - 555): An inventory of growth record sets Hunter, Baumrind, and Moyers) --------------------------------
  79. 79. Importance of growth studies: The analysis of many skeletal deformities can be aided greatly by the application of the methods referred to for the study of the growth at bones. Although some of these methods lend themselves primarily to experimental work on animals, they nevertheless will contribute to our fundamental knowledge of the subject and thereby supply information which can be of clinical importance. This will lead to both a better understanding and more intelligent treatment planning.
  80. 80. References: 1.Contemporary orthodontics: PROFFIT 2.Handbook of orthodontics: MOYERS 3.Dentofacial orthopedics with functional appliances: GRABER, PETROVIC, RAKOSI 4ARTICLES: •.Angle orthodontist; vol 52 no 2, april 1982 •AJO;vol 105 no 3, march 1994 •AJO; vol 112 no 1,2 , july 1997
  81. 81. •AJO;vol 56 no 5, 1969 •AJO;vol 55 no 6, 1969 •AJO; june 1993 •AJO;vol 58 no 6 , dec1970
  82. 82.