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Evaluation of orthodontic treatment out come


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Evaluation of orthodontic treatment out come

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. Contents • • • • Introduction Aims of ortho treatment Standards to judge the outcome Methods of evaluating outcome • Orthodontic treatment outcome of various modalities • • • • • • Occlusal outcome of orthodontic treatment Does growth affect outcome ??? Stability of orthodontic outcome Factors associated with standards and duration of ortho treatment Evidence – based treatment strategies Conclusion • • Indices Superimpositions • • • Removable Fixed Functional
  3. 3. Importance of evaluating treatment outcome • assess our work successful unsuccessful – achieved all objectives – Maintained the standards – Patient satisfaction patient clinician
  4. 4. Aims of orthodontic treatment • Jacksons triad : – Structural balance – Functional efficiency – Aesthetic harmony
  5. 5. Standards to judge the outcome • hard tissue • Soft tissue
  6. 6. • Andrew’s “Six keys to Normal Occlusion” would be a good starting point at which to aim in order to get desired tooth alignment. These are : • • • • • • Inter-arch relationship Mesio-distal crown angulations (TIP) Labio-lingual crown inclinations (TORQUE) Absence of rotations Tight contacts Occlusal plane (curve of spee)
  7. 7.
  8. 8. This key consists of seven parts 1] The mesiobuccal cusp of the permanent maxillary first molar occludes in the groove between the mesial and middle buccal cusps of the permanent mandibular first molar 2) The distal marginal ridge of the maxillary first molar occludes with the mesial ~marginal ridge of the mandibular second molar 3) The mesiolingal cusp of the maxillary first molar occludes in the central fossa of the mandibular first molar.
  9. 9. 4) The buccal cusps of the maxillary premolars have cuspsembrasure relationship with the mandibular premolars. 5) The lingual cusps of the maxillary premolars have cuspfossa relationship with the mandibular premolars. 6) The maxillary canine has cusp-embrasure relationship with the mandibular canine and first premolar. The tip of the cusp is slightly mesial to embrasure. 7) The midlines of the arches match.
  10. 10. CROWN ANGULATION • It is the angle formed by the facial axis of clinical crown [FACC] and as line perpendicular to the occlusal plane. • POSITIVE , if occ . of FACC mesial to gin. • NEGATIVE, if occ. of FACC distal to gin.
  11. 11. Key II. Crown angulation
  12. 12.
  13. 13. Crown inclination
  14. 14.
  15. 15.
  16. 16.
  17. 17. Crown inclination • It is the angle between as line perpendicular to the occlusal plane and as line that is parallel and tangent to the FACC • + OCC. Portion of crown is Facial to gin. portion • - OCC. Portion of crown is lingual to gin. portion • Consistent patterns in crown inclination exist. The individual teeth have the following characteristics. 1) Most maxillary incisors have as positive inclination; mandibular incisors have a slightly negative inclination. In most of the optimal sample,
  18. 18. 2) The inclinations of the maxillary incisor crown are generally positive, the central more positive than the laterals. Canine and premolars are also similar. The inclination of the maxillary first and second molars are also similar and negative, but slightly more negative than those of the canine and premolars. The molars are more negative because they are measured from the groove instead of from the prominent facial ridge. From which the canine and premolar are measured. 3) The inclinations of the mandibular crowns are progressively more negative from the incisors through the second molars.
  20. 20. Absence of rotations • There should be no undesirable rotations • Rotated molar or bicuspid occupies more space • A rotated incisor can occupy less space • Rotated canines adversely affect esthetics and may lead to occlusal interferences.
  21. 21.
  22. 22. Key V. Tight contacts • In the absence of such abnormalities as genuine tooth –size discrepancies, contact points should be tight
  23. 23.
  24. 24. Key VI. Curve of spee • A flat occlusal plane should be a treatment goal. • Measured from the most prominent cusp of the lower second molar to the lower central incisor, • No Curve of Spee was deeper than 1.5 mm in the non-orthodontic normals. • The depth of the curve of spee range from a flat plane to a slightly concave surface
  25. 25. • An excessive curve of spee restricts the amount of space available for the upper teeth, which must then move towards the mesial and distal, thus preventing correct intercuspation. • A normal occlusion has a flat occlusal plane. • The reverse curve of spee creates excessive space in the upper jaw, which prevents development of the normal occlusion.
  26. 26.
  27. 27.
  28. 28.
  29. 29. • However, these need to be further qualified by including functional goals in our treatment plan.
  30. 30. Optimum Functional Occlusion • When the mouth closes, the condyles are in their most superio-anterior (MSSP) position, resting on the posterior slopes of the articular eminences with the discs properly interposed. In this position there is even & simultaneous contact off all the posterior teeth . The anterior teeth also contact but more lightly than the posterior teeth.
  31. 31. • All tooth contact should provide axial loading of the occlusal forces.
  32. 32. • When a tooth is contacted on a cusp tip or a relatively flat surface such as the crest of a ridge or the bottom of a fossa, the resultant forces are directed vertically through its long axis. • When a tooth is contacted on an incline, however, the resultant force is not axial but rather a horizontal component is incorporated that tends to cause tipping with greater likelihood of
  33. 33. • The process of directing occlusal forces through the long axis of the tooth is known as : Axial Loading Axial loading can be achieved by Cusp tip to flat surface contact that are perpendicular to the long axis of the tooth. Tripodization: requires that each cusp tip contacting an opposing fossa be developed such that it produces three contacts surrounding the actual cusp tip.
  34. 34. • Any movement of the mand. From the intercuspal position that results in tooth contacts has been described as eccentric. • Three basic eccentric mandibular movement • Protrusive Retrusive Laterotrusive
  35. 35. • LATEROTRUSIVE : • Buccal cusp to buccal cusp contacts are more desirable during laterotrusive movements than are lingual cusp to lingual cusp. • Laterotrusive contacts must provide adequate guidance to disocclude the teeth on the opposite side of the arch (medio-trusive or the non working side) immediately.
  36. 36. • Medio-trusive contacts can be destructive to the masticatory system b’coz of the amount & direction of the forces that can be applied to the joint & the dental structures. • Some EMG studies suggest that the presence of mediotrusive contacts on the posterior teeth increases muscle activity. • Medio-trusive contacts should, therefore be avoided in developing an optimum functional occlusion.
  37. 37. • When the mand moves into a latero-trusive position, there should be adequate toothguided contacts on the latero-trusive (working) side to disocclude the mediotrusive (non-working) side immediately. The most desirable guidance is provided by the canines (canine guidance).
  38. 38. • When the mand is moved in a right / left laterotrusive excursions, the max & mand canines are the appropriate teeth to contact & dissipate the horizontal forces while dis-articulating the posterior teeth. • This condition is called canine guidance or canine rise
  39. 39. • Lever system of the mand • Comparable to a nut cracker • Greater force can be applied to an object as its position nears the fulcrum. • Hence, the damaging horizontal forces of eccentric mand movements must be directed to the anterior teeth, which are positioned farthest from the fulcrum & the force vectors. • Thus, the amt of force applied to the ant. teeth is less than would be applied to the post. teeth , & the likelihood of breakdown is minimized.
  40. 40. • Of all the teeth canines are best suited to accept the horizontal forces of eccentric movements b’coz : • They have longest & largest roots & therefore, the best crown – root ratio. • They are surrounded by dense compact bone which tolerates forces better than does medullary bone found around the posterior teeth. • Sensory inputs: fewer muscles are active when canines contact during eccentric movements than when posterior teeth contact. • Lower levels of muscular activity would decrease forces to the dental & joining structures &
  41. 41. • When canines are no in proper position to accept horizontal forces, other teeth must contact during eccentric movements. • The most favorable alternative to canine guidance is the Group Function : several teeth on the working side contact during laterotrusive movements. • The most desirable group function consists of the canines, premolars & sometimes the mesio-buccal cusp of the 1st molar. • Contacts post. than the mesial portion of the 1st molar are not desirable b’coz of the increased amt of force that can be placed as they near the fulcrum & force vectots.
  42. 42. • PROTRUSIVE MOVEMENTS • When the mand moves into a protrusive position, there are adequate tooth guided contacts on the anterior teeth to disocclude all the posterior teeth immediately. • In the alert feeding position, posterior tooth contacts are heavier than the anterior tooth contacts.
  43. 43. • When the mand moves forward into protrusive contact, damaging horizontal forces can be applied to the teeth. • Therefore, anterior teeth & not the posterior teeth should contact & the anterior teeth should provide adequate contact or guidance to disarticulate the posterior teeth.
  44. 44. • Thus, anterior & posterior teeth function quite differently : • Anterior teeth are in proper position to accept the forces of eccentric mand movements & function most effectively in guiding the mand during eccentric movements. • Posterior teeth function effectively in accepting forces applied during the closure of the mouth. • This condition is described as “Mutually Protected Occlusion”
  45. 45. Aesthetic harmony
  46. 46. Soft tissue parameters • • • • • Nasolabial angle Upper / lower lips to E – line Upper / lower lips to s- line Lip strain Angle of convexity
  47. 47. Methods of evaluating outcome • Material used : – Casts – Photographs – Radiographs • Methods used : – Indices – Superimpositions – Palatal rugae
  48. 48. • Indices : – – – – – – Par (peer assessment rating) ICON (index of complexity , outcome and need ) ABO –OGS ITRI (ideal tooth relationship index ) Littles irregularity index Peerling index
  49. 49. Par index • Peer assessment rating • Developed in 1987 • Provides a score for various occlusal traits which make up a malocclusion
  50. 50. Components of PAR
  51. 51. Displacement • SCORE 0 1 2 3 4 5 DISPLACEMENT 0 – 1 MM 1.1 – 2MM 2.1 – 4MM 4.1 – 8 MM GREATER THAN 8 MM IMPACTED TEETH
  52. 52.
  53. 53. Buccal occlusion
  54. 54. Overjet
  55. 55. Overbite
  56. 56. Centerline
  57. 57. Conventions for the PAR Index • General: – 1. All scoring is accumulative. – 2. There is no maximal cut-off level. – 3. The occlusion should be scored disregarding functional displacement – 4. The contact points between first, second, and third molars are not recorded
  58. 58. • 5. If the contact point displacement is as a result of poor restorative work (restorations or crowns), the displacement is not recorded. • 6. Contact points between deciduous teeth are not recorded. • 7. Extraction spaces are not recorded if the patient is to receive a prosthetic replacement. However, if space closure is intended, the distance between adjacent teeth should be noted.
  59. 59. • Canines: .~ • 1. Where there are missing canines, displacements resulting from discrepancies between the mesial contact point to the first premolar and the distal of the lateral incisor should be recorded in the anterior segment. • 2. Canine cross-bites should be recorded in the overjet section.
  60. 60. • 3. Contact points between the canines and premolars are scored as follows' the distal contact point of the canine to the midpoint on the mesial surface of the adjacent premolar. • Impactions: • If a tooth is unerupted and displaced from the line of the arch either buccally or palatally due to insufficient space, this is regarded as an impaction. However, if the tooth is erupted and displaced, the displacement score is recorded.
  61. 61. • Incisors: • 1.) If there is agenesis of the upper incisor or the tooth has been lost due to trauma or caries the procedure is as follows: – a. If the space is maintained (for a prosthesis), the distance between adjacent teeth is not recorded; – b. If the space is to be closed, the distance between adjacent teeth is recorded.
  62. 62. • 2. When recording an overjet, if the tooth falls on the line the lower grade is recorded. • 3. If a lower incisor has been extracted or is missing, the centerline is not recorded. • Molars: – 1. Contact points between first and second molars are not recorded. – 2. If the first molars have been extracted, the contact point of the second molar is recorded.
  63. 63. PAR RULER
  64. 64.
  65. 65. Nomogram
  66. 66. Rating • 30 % reduction was needed for a case to be judged improved • Change in score of 22 – considered greatly improved
  67. 67. Index of Complexity, outcome and Need (ICON) • General Assumptions of the Index • 1. When the index is used to assess treatment outcomes, it is assumed that an appropriate level of co-operation was obtained from the patient. • 2. The index may require confirmation of the presence of teeth using radiography. • 3. Except for the aesthetic assessment, occlusal traits are not scored to deciduous teeth unless they are to be retained in the permanent dentition to obviate the need for a prosthetic replacement, for example, when the permanent tooth is absent.
  68. 68. The index contains five components, • • • • • 1 ) Dental Aesthetics 2) cross bite 3) anterior vertical relationship 4) upper arch crowding / spacing 5) buccal segment antero-post. relationship
  69. 69. -
  70. 70. Protocol for scoring
  71. 71. Weight age
  72. 72. Complexity scores
  73. 73. Improvement scores
  74. 74. Treatment need • Accuracy : 85.5 • Sensitivity : 85.2 • Specificity : 86.4
  75. 75. Treatment outcome • Accuracy : 69 • Senstivity : 71.8 • Specificity : 64.1
  76. 76. ABO – OGS CRITERIA • 8 FEATURES • • • • • • • • alignment marginal ridges buccolingual inclination occlusal relationship occlusal contacts overjet interproximal contacts root angulation
  77. 77. ABO Measuring Gauge
  78. 78. ALLIGNMENT
  79. 79. • • • • Score 0.5- 1 mm >1 mm Total 64
  80. 80. Marginal ridges • Score • 0.5-1mm • >1mm • Total = 32
  83. 83. • Score • >1 – 2 mm • >2 mm • Total = 40
  84. 84. Occlusal contact
  85. 85. • Score • 1 or less • >1 • Total = 64
  86. 86. Occlusal relation • Score • 1-2 mm • >2 mm • Total = 24
  87. 87.
  88. 88. OVERJET
  89. 89. • Score : • 1 or less • >1 • Total = 32
  91. 91. • Score : • 1mm • >1 mm • Total = 60
  92. 92. Radiograph
  93. 93. • Score • >1 – 2 mm • >2 mm • Total = 64
  95. 95.
  96. 96. Result • A sample which looses less than 20 points PASS • A sample which looses more than 30 points FAIL
  97. 97. ITRI •Occlusal analysis was developed that looked at : •inclined planes • interproximal contacts •anterior occlusal contact • specific cusp and marginal ridge relationships.
  98. 98. -------------------------------•The use of an ideal tooth relationship index (ITRI) : •evaluating the results of rthodontic treatment • posttreatment stability •Settling •relapse •different orthodontic treatment modalities.
  99. 99. Assuming that all teeth are present, there are 62 potential ideal tooth relationships that make up ITRI
  100. 100. •BASIS :: The index was based on the percentage of actual to potential ideal relationships present on the dental casts and was calculated as the sum of maxillary buccal cusps, mandibular lingual relationships, and anterior and interproximal contacts divided by the number of potential relationships.
  101. 101. •The ITRI scores were computed for the following: • total index score for the entire dentition; •anterior segment score, which is the summation of intraarch and interarch scores; • posterior segment score, which is the summation of intraarch and interarch scores, including buccal and lingual scores.
  102. 102. •"The number of potential ideal relationships varied depending on the number of teeth included, i.e., extraction cases and inclusion of second molars. The relationships were scored only when they were correct, and no range of normal" was incorporated. However, if a buccal segment interdigitated mesially or distally to the Class I position, contacts were still counted as being present since functional inclined plane relationships were of primary interest. •Models with congenitally missing teeth, questionable articulation, malformed teeth, or broken or chipped teeth were not included in this study.
  103. 103. • Third molars were not included because of variability in form and occurrence. • Second molars were included initially but subsequently eliminated on the basis of a pilot study that revealed no difference in scores if only first molars were included. • Deciduous teeth were excluded. • In some cases, band spaces were present resulting in a lack of interproximal contact; these were not recorded as correct.
  104. 104. Shortcomings of ITRI : •No range was incorporated into the presence or the absence of ideal relationships. Thus a correction of 95% would still be counted as a missed relationship. This stringency tends to mask much of the improvement that may be very acceptable clinically and may help to explain why treatment scores appear to be low. • In interpreting changes that occurred, one must be aware of what level or component of the index is being discussed.
  107. 107. PEERLING INDEX • Photographs of boys and girls between 11-13 and 14- 16 yrs were collected in 4 albums
  108. 108.
  109. 109.
  110. 110. Superimposition • Spatial change of craniofacial structures is evaluated by superimposition of cephalometric tracing taken at different times • Methods of superimposition differ acc. To reference structures used within the skull
  111. 111. Superimposition can be done at • 1 ) cranial base • 2) maxilla • 3) mandible
  112. 112.
  113. 113. Cranial base • 4 major methods : • 1) superimposition on the best fit anterior cranial base anatomy - de coster
  114. 114. • 2) Superimposition on sella – nasion - (Steiner ) • 3)superimposition at registration R point with bolton nasion plane - (BROADBENT ) • 4 ) superimposition on basion – nasion plane - ( RICKETTS )
  116. 116. MANDIBLE • 1 ) lower border of mandible and its tangent - ( BRODIE ) • 2 ) BJORK – – Inner cortical structures of inferior border of symphysis – Detailed structure of mandibular canal – Lower contour of mand. germ
  117. 117. Ricketts superimposition
  118. 118.
  119. 119. • The average of side effects on mandibular rotation is as follows; • 1) Convexity reduction: Facial a.xis opens 1 degree/ 5mm • 2) Molar correction: Facial a.xis opens 1 degree / 3mm • 3) Overbite correction: Facial axis opens 1 degree /4mm • 4) Cross bite correction.: Facial axis opens 1-1 1/2 degree • 5) Dolico facial pattern :Tendency for facial a.xis to open 1 degree per 1 S.D. • 6) Brachy facial pattern: , Tendency for facial axis to close 1 degree • Facial a.xis may close with extraction.
  120. 120. • The point A changes with various mechanics is as follows: • MECHANI CS – – – – – – RANGE a) H.G. b) Class II Elastics c) Activator d) Torque 2mm e) Class 111Elastics 3mm f) Face Mask 4mm. 8mm 3mm 2mm -1 mm + 2mm +2 mm
  121. 121. Pitchfork analysis • Present approach views the correction of malocclusion molar relationship and overjet-as the end result of a series of physical displacements produced by • growth and tooth movement • displacement of maxilla relative to cranial base, • movement of maxillary dentition relative to maxillary basal bone, • translation of mandible relative to cranial base, • movement of mandibular dentition relative to mandibular basal bone.
  122. 122. • Component displacements are measured in a comparable manner and each is given a sign appropriate to its impact: • positive if it would tend to correct a Class II molar relationship or reduce overjet (as would be the case, say, with forward growth of the mandible or mesial movement of the lower molars and incisors); • negative, if it increases the overjet or moves the molar relationship toward Class II (e.g. as with forward growth of the maxilla or mesial, movement of the upper dentition). • Given this sign convention, the algebraic sum of the various antero-posterior skeletal and dental effects would equal the change in molar relationship and overjet.
  123. 123. Pitchfork diagram
  124. 124.
  125. 125.
  126. 126.
  127. 127.
  128. 128. The use of palatal rugae for the assessment of anteroposterior tooth movements • The purpose of this study was to assess the relationship between posterior occlusion and posttreatment changes in other occlusal variables.
  129. 129.
  130. 130.
  131. 131. Results • 1. Anteroposterior molar and incisor movement maybe assessed as accurately with dental casts as with maxillary cephalometric superimpositions. • 2. The medial end of the third palatal ruga is a suitable landmark for serial model analysis of molars and incisors. • 3. The use of study models to evaluate anteroposterior anchorage, particularly during treatment, presents the clinician and the researcher with an alternative to taking a cephalometric radiograph, given the limitations of not being able to evaluate incisor tipping or vertical movements.
  132. 132. Orthodontic treatment outcome of various modalities • Removable • Fixed • Functional
  133. 133. Assessing treatment effectiveness of removable and fixed orthodontic appliances with the occlusal index Orthodontists from different backgrounds may have different opinions about removable and fixed orthodontic appliances, but there have been few objective comparisons of their relative treatment effectiveness In this study – 80 cases removable - 67 fixed
  134. 134. The Occlusal Index was proposed by Summers in 1966.1 Nine weighted and defined measurements were included in the Occlusal Index: molar relationship Overbite  overjet posterior crossbite posterior open bite tooth displacement  midline relation maxillary median diastema congenitally missing maxillary incisors.
  135. 135.
  136. 136. •The average reduction in Occlusal Index scores after therapy with removable orthodontic appliances was found to be less than that obtained with fixed appliances,the improvement in occlusion produced by fixed appliances was much greater than that produced by removable appliances. • Most of the patients treated with fixed appliances had major reductions in OI scores, especially those with the most severe pretreatment malocclusions compared to patients who had been treated with removable appliances showed major reductions in OI scores, many had only minor reductions. This inconsistency indicated that treatment effects and treatment results produced with removable appliances were much more variable and less predictable than those obtained with fixed appliances.
  137. 137. •The removable appliances tend to correct symptoms of malocclusion rather than the basic orthodontic defect •Begg and Edgewise appliances were compared, the present study found no statistically significant difference between their treatment effectiveness or their treatment results •REMOVABLE APPLIANCES not effective in moving the tooth bodily , close extraction spaces, mesiodistal , buccolingual inclinations. They can only tip •Kerr (bjo 1993 ) :removable appliances only effective in treating crossbite , ectopic tooth position , ant. Spscing, overjet and less in rotation , crowding , molar relation
  138. 138. Comparison of the Outcome of treatment Using Two Fixed Appliance techniques~ • Comparison of the two different appliiance types found that the pre-adjusted Edgewise group achieved a significantly greater reduction in PAR score (81 per than the Begg group (65 per cent). • Cases with a low PAR score prior to treatment tended to fare more poorly in terms of percentage reduction and this was more marked for those cases treated with the Begg appliance • . Although the index has a high degree of reproducibility, it was found that even the small error present can lead to problems of “interpretation if the nomogram categories are used as a method of comparison.
  139. 139. FUNCTIONAL APPLIANCES • Hypothesis : functional appliances enhance mandibular growth in the treatment of skeletal Class II malocclusions. • Previous studies have shown varying degrees of success in the treatment outcomes, functional appliance use remains controversial. • A treatment outcome that has been particularly questioned is the enhancement of mandibular growth.
  140. 140. • It was not until the 1970s that the use of functional appliances became widespread in the United States. • This was, in part, the result of landmark studies in animals that demonstrated that skeletal changes could be produced by posturing the mandible forward. • The initial studies seemed to validate the concept that soft tissue stretching can promote bone growth. • Many studies followed, but later studies performed on humans were more equivocal and showed less impressive results. • Therefore, the controversy remains regarding the efficacy of functional appliances to correct Class II malocclusions.
  141. 141. • It is currently difficult to obtain definitive answers about appliance efficacy from the literature because of many inconsistencies in measuring treatment outcome variables • Some investigators use condylion (Co) as the posterior end point in measuring the overall mandibular length, whereas others use articulare (Ar). • In addition, durations of treatment vary, as do the lengths of follow-up; and treatment groups are sometimes compared with untreated control groups or with groups undergoing other forms of treatment, such as headgear.
  142. 142. RECENT STUDIES • Illing et al, 1998 Bass, Bionator, Twin-block • Ghafari et al, 1998 Fra¨nkel Headgear • Cura et al, 1997 Bass • Tulloch et al, 1997 Bionator • Webster et al, 1996 Fra¨nkel & Harvold • Nelson et al, 1993 Fra¨nkel & Harvold
  143. 143. • Linear measures were assessed: • condylion-pogonion (Co-Pg) • articulare-pogonion (Ar-Pg), • Condylion-gnathion (Co-Gn) • articulare-gnathion (Ar-Gn) • sella-gonion (S-Go) • articulare-gonion (Ar-Go) • condylion-gonion (Co-Go). • Two angular parameters: • • sella-nasion-B point (SNB) lower incisal angle (LIA), • Three horizontal measurements : • gonion-menton Go-Me) • pogonion to N (Pg to N), • gonion-pogonion (Go-Pg).
  144. 144. RESULTS • For Co-Pg, Co-Gn, SNB, LIA, and other horizontal measurements, there is no significant difference between the untreated control group and the group treated with functional appliances. • However, for Ar-Pg and Ar-Gn, there was a significant difference between the control and the treated groups. • Although these appliances can be used for other purposes, these results suggest the need to reevaluate functional appliance use for mandibular growth enhancement. • These results complement those of quasi-experimental studies with discriminant analysis but differ from nonsystematic reviews that provide qualitative summaries. (Am J Orthod Dentofacial Orthop 2002;122:
  145. 145. Occlusal outcome of ortho treatment • Ajo 1992 • 92 treated malocclusions consisting of 36 Class I, 25 Class II, Division 1, 17 Class II, Division 2, and 14 Class III malocclusions were obtained. • The dental casts were analyzed • before treatment (A) • at the time the appliance was removed (B) • approximately 4 years later (C).
  146. 146. Total index scores improved from 26.8% to 52.1% as a result of orthodontic treatment and increased to 58.7% during the posttreatment period, • Orthodontic treatment improved ideal tooth relationships, which generally continued to improve during retention thus reflecting a settling effect. • Analysis of treatment results showed that anterior segments improved more than posterior segments, and buccal relations are handled better than lingual relations. It appears orthodontists do a better job correcting discrepancies that are more highly visible. •. Occlusal relationships after orthodontic treatment were improved to approximately the same degree regardless of the type of malocclusion and, thereafter, showed similar settling and relapse.
  147. 147. • Before treatment • Class I : higher total ITRI • Class II : higher posterior ITRI • After treatment • No difference • Post retention • Class II div I : 15% higher in posterior
  148. 148. Does growth affect occlusal outcome ??? • Assessment of biological changes in a non orthodontic sample using the PAR index(Am J Orthod Dentofacial Orthop1998;) • The results indicate that there were no significant differences between the mean Peer Assessment Rating score at 12 years of age and at 22 years of age • The changes were irrespective of the Angle classification or the treatment need. • Changes over time in the weighted Peer Assessment Rating score were mainly correlated to changes in the anterior crossbite and the overjet. • This correlation may be influenced, however, by the applied weighting factor for those occlusal traits.
  149. 149. Stability of orthodontic outcome
  150. 150. Orthodontic treatment need prior to tretment and 5 years postretention • (community dent oral epi 1998) • • Dental casts evaluated using IOTN RESULTS – – on the basis of combined dhc and ac scores 83 % of pt. who started ortho treatment had an objective need for ortho tratment – 10 % still showed a definite need • in another study by burger (1995) showed 44 % of patients who showed a definite need
  151. 151. • The remaining treatment need showed a correlation with the year of ortho treatment was started • But treatment duration did not diminish although treatment tech. has evolved • There seems to be a secular trend in ortho outcome but effectiveness in terms of treatment duration did not increase
  152. 152. Factors influencing outcome • .(i) Personal factors • Sex • Age at start of treatment • (ii) Occlusal factors • Incisor classification (Class I, III I , III2 or III, according to British • Standards Institute definition) • Developmental stage (mixed dentition, permanent dentition) • Pretreatment PAR score • Size of overjet (mm) • Presence/absence of anterior crossbite • Presence/absence of ectopic teeth
  153. 153. • ;. • (iii) Co-operation factors • Pretreatment oral hygiene (good. fair, poor. no indication) • Number of broken appointments • Number of removable appliances broken or lost • Number of bands/bonds dislodged or archwires broken • Whether or not the original treatment plan was altered
  154. 154. • treatment factors • Appliance type (two-arch fixed, removable/mini-fixed) • grade (consultant, senior registrar, postgraduate student ,undergraduate • Extrction pattern (non-extraction, four premolars, first permanent molar • No. of removable appliances used • Whether or not headgear was worn • Outcome variables • • • • Post-treatment PAR score Change in ,PAR score Duration of active treatment No. of appointments during active treatment
  155. 155. Timing of ortho treatment • a recent workshop on early treatment, the majority of the participants estimated that the 30% to 50% of their practices involves patients who, in their opinion “NEED an early phase of treatment.” • a 2-stage approach, particularly applied to the most common problems encountered in clinical practice —the resolution of crowding and Class II malocclusions.
  156. 156. • Crowding can be resolved in most instances by simple arch length preservation • There is no clinically important difference in the outcomes of 2-stage and 1-stage Class II treatment except for a longer treatment time in the 2-stage samples.
  157. 157. • An evidence-based approach has at least 2 components. • One is composed of individuals who pursue information by means of rigorous hypothesis testing involving formulating an appropriate question, reducing variability, collecting data with a defined protocol, and analyzing the data by means of an accepted method. • The second component comprises practitioners whose duty is to evaluate the merits of new data before adopting a practice strategy based on the findings.
  158. 158. Conclusion • This scenario raises an important issue on the eve of the 21st century. • Will orthodontics accept an “evidence-based” approach to treatment decisions? • Is orthodontics ready to alter treatment strategies if the purported claims are not supported by fact? • An evidence-based approach is attractive for a number of reasons. One is that it will serve our patients better because only tested strategies will be endorsed. • A second is that it will elevate orthodontics to a higher level because it will ensure that we are offering proven treatments. •
  159. 159. • In the final analysis, the practitioners will control the destiny of evidence-based treatment strategies in orthodontics because they are responsible for transferring information to their patients. • This is one of the many reasons that the future of the specialty is in their hands.
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