Retention-and-Relapse- for dental medicine studentsPpt.pptx

lecture notes

1. RETENTION & RELAPSE lecture notes by Dr.Dida Boru(assistant professor@JU) for CII dental medicine students

2. C ontents Introduction History Need for retention Theorems 6 keys Relapse -soft tissue -Functional -Skeletal Retainers RETENTION RELAPSE

3. INTRODUCTION No matter how good things look for one team late in the game, the saying is "It's not over till it's over." In orthodontics, although patient may feel that treatment is complete when appliances are removed, an important stage lies ahead. Orthodontic control of tooth position and occlusal relationships must be withdrawn gradually, not abruptly, if excellent long-term results are to be obtained. The type of retention should be included in original treatment plan

4. According to Webster RETAIN – ( re+tenere – to hold) means to “hold back or to hold secure ” RELAPSE: “to slip or fall back to a former condition, especially after improvement or seeming improvement”

5. Retention has been defined by Moyers as “ the holding of teeth following orthodontic treatment in the treated position for the period of time necessary for the maintenance of the result ” Riedel “ the holding of teeth in ideal aesthetic and functional position.” According to Graber working definition of retention in relation to orthodontics might be stated as follows: the holding of teeth in optimal aesthetic and functional positions .

6. HISTORY

7. HISTORY Clinicians did not agree about the need for retention Hellman : “ We are in almost complete ignorance of the specific factors causing relapse” No mention of retention appliance or need for retention upto 1860 Difference philosophies/schools of thoughts have existed over time, and present-day concepts generally combine several of the following historic concepts regarding retention .

8. 1860 - Emerson C. Angell- retention of space after opening of maxillary median suture. After more than 19 centuries, concept of retention appliance was born. Alfred Coleman (1865) “ restoration of the former condition by muscular pressure “- relapse Brown-Mason (1872) - Described a retaining plate for surgically rotated teeth.

9. The problem of maintaining teeth in their new position after treatment was first recognized by Kingsley in 1880, who advocated use of ‘retaining plates’ to maintain positions of teeth He stated that "the occlusion of the teeth is the most potent factor in determining the stability in a new position” Based on this concept, he developed “occlusion school” of retention . The Occlusion School

10. James W. Smith (1881 ) -A simple vulcanite plate with a bar extending over the labial aspect of the maxillary incisor teeth. Victor Hugo Jackson- 1904- “ Not infrequently cases are presented that require more skill in retaining the teeth than in regulating them” Hahn - “Retention in orthodontics is like a neglected step-child This concept was well supported by Angle in 1907 who stated : “ every person can maintain full complement of dentition and stability will depend on how fine occlusion has been achieved”

11. 1900 – Edward H Angle "normal occlusion" during eruption period- relapse . Cutting gingival fibers to counteract rotations. In doubtful cases, wearing delicate and efficient appliances indefinitely. Pin and tube appliance. ( working retainer )- uprighting teeth that have been tipped outward during expansion

12. 1919- Hawley “give half his fee to anyone who would be responsible for the retention of his results when the active appliance was removed” 1920 AJO- Calvin Case "Principles of Retention in Orthdontia "

13. Apical Base School Compromised stability due to Angle’s philosophy of arch expansion lead to development of “The apical base school” Axel Lundstrom (1920) “ Apical base was one of the most important factors in the correction of malocclusion and maintenance of a correct occlusion”

14. McCauley (1944) “ Intercanine and intermolar width should be maintained as originally presented to minimize retention problems ” Strang (1946)- further confirmed and substantiated this concept. Nance (1947 ) “ arch length may be permanently increased only to a limited extent”

15. Grieves (1944) “ mandibular incisors must be kept upright and over basal bone” Cause : forward translations of teeth Tweed (1954) 5 yrs retention and even longer when needed Mandibular Incisor School

16. Rogers (1951) “Care must be exercised to establish a proper occlusion within the bounds of normal muscle balance with careful regard to the apical bases and their relationship to one another” Hellman - retention, not a separate problem, continuation of what we are doing during treatment. the Musculature school

17. Factors affecting type and length of retention How many teeth have been moved and how far. Occlusion and age of the patient. Cause of the particular malocclusion. Rapidity of corrections. Length of cusps / relationship of the inclined planes. Health of the tissues involved. Cell metabolism Arch harmony. Graber vanasdall

18. Factors to consider for retention Rotation should be corrected by overrotation in the opposite direction. Slight movement is more difficult to retain than extensive movement. Occipital retention is most desirable for certain cases . Function is the most important factor in retention. Retention depends on bone change, which in turn is related to endocrine dysfunction. Use of mild forces is desirable. Graber vanasdall

19. Mandibular incisors should be maintained upright over basal bone. Discrepancies in tooth sizes may cause problems in retention. Early treatment is more desirable than treatment at a later age. Intercanine and intermolar widths should be maintained as in the original malocclusion

20. Richard A Riedel – 1960 Riedel proposed some basis for holding te eth in their treated position as: (1) allowing for periodontal and gingival reorganization (2) to minimize changes from growth (3) to permit neuromuscular adaptation to the corrected tooth position (4) to maintain an unstable tooth position, if such positioning is required. Classified retention according to the requirements of various types of cases and given 9 Theorems

21. Theorem - 1 Teeth that have been moved tend to return to their former positions. Reasons : Musculature Transseptal fibers Bone morphology

22. Elimination of the cause of Malocclusion will prevent recurrence . Habits, Tongue posture, mouth breathing Theorem - 2

23. Malocclusion should be overcorrected as a safety factor Class II: edge-to-edge over-corrections may be the result of overcoming muscular balance rather than absolute tooth movement Theorem - 3

24. Proper occlusion is a potent factor in holding teeth in their corrected positions. Maintain health of the periodontium . Functional occlusion. Theorem - 4

25. Bone and adjacent tissues must be allowed time to reorganize around newly positioned teeth Fixed retention- “G wire,” band and spur type of attachment and bands soldered together’ No positive fixation- retainers should be only inhibitory and should have no positive fixation to allow for the natural functioning of teeth Mandibular lingual arch can be used Theorem - 5

26. Gottlieb (1935), Oppenheim (1935) and Orban (1936) - First orthodontic literature on microscopic studies of bundle and lamella bone spicules . Oppenheim – appliances should only be inhibitory and that repair of tissues around the teeth occurs much more rapidly if no fixed retaining appliance is used Hixon – Muscular balance

27. If the lower incisors are placed upright over basal bone, they are more likely to remain in good alignment . Better - towards the lingual than labial inclination. Physiologic migration of lower anterior in distal direction. M aintaining arch form. Theorem - 6

28. Raleigh Williams Several steps during fixed appliance to eliminate need for lower retention 20 yrs postretention 6 treatment keys Eliminating lower retention . JCO May 1985

29. Incisal edge of lower incisor should be placed on A-P line or 1mm in front of it. KEY 1

30. The lower incisor apices should be spread distally to the crowns The apices of lateral incisors incisors should be spread more than those of the central incisors KEY 2

31. The apex of the lower cuspid should be positioned distal to the crown. Occlusal plane- positioning guide KEY 3

32. All four lower incisor apices must be in same labio -lingual plane KEY 4

33. The lower cuspid root apex must be positioned slightly buccal to the crown apex . KEY 5 KEY 6 The lower incisors should be slenderized as needed after treatment

34. Corrections carried out during periods of growth are less likely to relapse. Theorem - 7

35. The farther teeth have been moved, the less likelihood there is of relapse . Theorem - 8

36. Arch form, particularly in the mandibular arch, cannot be permanently altered by appliance therapy. Mc Cauley “Since molar width and canine width are of such an uncompromising nature, one might establish them as fixed quantities and build arches around them” Theorem - 9

37. Why is Retention necessary ? Proffit - Reorganization of gingival and periodontal tissues after orthodontic treatment. Soft tissue pressure – relapse tendency. Changes produced by growth may alter treatment results.

38. Reorganization of gingival and periodontal tissues after orthodontic treatment. Widening of pl space – disruption of fibers Teeth respond individually to forces of mastication Reorganization 3-4 months Slight mobility disappears

39. Soft tissue pressure Active stabilization Gingival fibers Collagen 4-6 month Elastic- 12 months

40. Slow turnover of periodontal ligament fibers Especially supracrestal elastic fibers has been cited as a principle factor for post orthodontic treatment instability in relation to rotational tooth movement Edwards demonstrated circumferential supracrestal fibrotomy (CSF) as an effective strategy to reduce irregularity index relapse after active orthodontic treatment at 5 years (1.03 mm) but was less effective at 13 years ( 2.56 mm ). This shows s hort term(1-year) effectiveness of CSF in reducing posttreatment recrowding

41. Need for retention Elastic Recoil of Gingival Fibers Cheek / Lip / Tongue Pressure Differential Jaw Growth Intra-Arch Irregularity Changes in Occlusal Relationship

42. Stability of early orthodontic treatment

43. Haruki and Little (1998) during an evaluation of differences in the long-term stability after a minimum of 10 years between patients who received early orthodontic and those treated late; both groups treated with 4 first bicuspid extractions. They found late treatment group had greater mandibular anterior irregularity and deviation of midline . Little et al (1981) and Richardson et al stated that: “Treated cases should be viewed as dynamic and constantly changing, at least through the third and fourth decade and perhaps throughout life.”

44. Burlington study a) Late developmental crowding is a process which continues throughout life. b) The rate of increase in crowding or irregularity of the lower incisors seems to decrease with increasing age (≥40 years). Sadowsky et al suggested that prolonged retention of lower labial segment until end of facial growth may reduce severity of lower incisor crowding.

45. Dugoni et al (1995) defended post-retention stability in early orthodontic treatment in patients who had early mixed dentition treatment using a passive lingual arch for alignment of lower incisors. These cases had no appliance therapy in permanent dentition or circumferential supracrestal fiberotomy or interproximal enamel reduction after removal of the bonded retainers

46. Overbite, overjet , and other dental changes Maintenance of the natural space for lower incisor alignment Anterior component of force resulting in mesial migration of teeth—a retention nightmare Role of third molars in the development of mandibular incisor crowding—the easy answer, but so controversial Mandibular growth and its effect on late mandibular incisor crowding Factors which significantly influence the retention decision

47. Overbite, overjet , and other dental changes Overbite and overjet increase significantly from mixed to permanent dentition. Decreases in overbite and overjet were observed by Barrow and White,Björk , Moorrees and Sinclair and Little. Arch length decreases over time. Longitudinal data show that changes in arch dimensions, as well as lower incisor crowding occur as part of the normal aging process.

48. Maintenance of the natural space for lower incisor alignment Lower incisors procline relative to mandibular plane by an average of between 5 and 11 years. This gain in space is enhanced by an increase in arch width across canines caused by alveolar growth just before and during the eruption of permanent incisor

49. Anterior component of force resulting in mesial migration of teeth—a retention nightmare Mesial migration of posterior teeth during adolescence has been recognized by Hunter. Thus responsible for increase in crowding during teenage years . Mesial migration caused by - physiological mesial drift, by anterior component of force of occlusion on mesially inclined teeth M esial vectors of muscular contraction Contraction of transseptal fibers of periodontal ligament

50. Role of third molars in the development of mandibular incisor crowding— Removal of second molar effectively isolates third molar from rest of arch . Reduction in crowding and distal movement of first molars in patients whose second molars have been extracted was compared with increase in crowding and mesial movement of first molars in nonextraction subjects provide convincing evidence of effects of developing third molars on the anterior part of arch.

51. Ades et al. compared four groups of patients who were a minimum of 10 years out of orthodontic retention. Patients studied had one of the following bilateral mandibular third molar status: (1) third molars erupted into good alignment and function . (2) third molar agenesis (3) third molar impaction (4) third molar extraction at least 10 years before postretention records. They found no differences in mandibular incisor crowding, arch length, intercanine width, and eruption patterns of mandibular incisors and molars between the groups. In majority of cases, some degree of mandibular incisor crowding took place after retention but it was not statistically significantly different between third molar groups.

52. M andibular third molar removal with sole objective of alleviating or preventing mandibular incisor irregularity may not be justified

53. It is a mistaken impression that it is only impacted third molars that cause the problem. A third molar that erupts is likely to exert more pressure on the dental arch than one that remains impacted, and some impacted third molars may exert more pressure than others. Decisions relative to the timing of third molar extraction should be made on the basis of potential development of pathosis , technical considerations of the surgical procedure and long-term periodontal implications rather than potential impact on mandibular incisor crowding.75 Although erupting mandibular third molars probably exert some force on the dentition,67,74–78 most of the scientific studies69,79–82 have found no significant correlation between the presence or absence of mandibular third molars and developmental incisor crowding. The effect of mandibular third molars on the dentition, particularly the lower incisors, remains unclear according to Bishara and Andreasen.82 Irrespective of the impact of all the latter factors, be aware that as a group they all have a minor or major impact on occlusal changes. Thus, to ensure that a treatment result is maintained retention compliance remains an imperative part of the orthodontic treatment regimen

54. Mandibular growth and its effect on late mandibular incisor crowding Changes in mandibular growth direction and rotation during post-treatment and postretention periods have implicated in etiology of late incisor crowding. Vertical development of mandibular ramus continues until late adolescence Buschang et al - Crowding of mandibular incisors was observed in vertical growers as a result of chronic airway obstruction

55. Retention Protocol Retainer should be in place at least for the same duration as the treatment time(depending on the age) A classic regimen is to wear retainers full time for half of treatment time. Then divide remainder of treatment time in two periods; first period is for at home wear and second period is for night-time wear ; It is recommended to maintain night wear until the longterm changes have minimal effect

56. Expansion appliance must be maintained passively for approximately 16 weeks followed by removable retention appliance . Storey - slow separation with continued growth of mature bony serrations within suture provides the best retention with the least potential for relapse Graber vanasdall

57. The Irregularity Index Measuring linear distance from anatomic contact point to adjacent anatomic contact point of mandibular anterior teeth, sum of five measurements Perfect alignment from the mesial aspect of left canine to mesial aspect of right canine have a score of 0, with increased crowding represented by greater displacement and, therefore, a higher index score.

58. FACTORS THAT AFFECT POSTTREATMENT STABILITY Alteration of arch form Periodontal and gingival tissues Mandibular incisor dimensions Influence of environmental factors and neuro musculature Post treatment tooth positioning and establishment of functional occlusion Consideration of continuing growth Role of developing third molars Influence of the elements of the original malocclusion Blake and Bibby ; Retention and stability: A review of the literature; 1998; AJODO

59. Retention After Class II Correction Do not move lower incisors too far forward because lip pressure will tend to upright the protruding incisors, leading to crowding and return of both, overjet and overbite. If more than 2 mm of forward repositioning of the lower incisors occurred during treatment, permanent retention will be required Relapse result from some combination of tooth movement (forward in the upper arch, backward in the lower arch, or both) and differential growth of the maxilla relative to the mandible .

60. Overcorrection of the occlusal relationships as a finishing procedure is important step in controlling tooth movement that would lead to Class II relapse. Even with good retention, 1 to 2 mm of anteroposterior change caused by adjustments in tooth position is likely to occur after treatment, particularly if Class II elastics were employed

61. In Class II patients, this relapse tendency can be controlled in one of two ways. Fixed appliance approach of 1970s is to continue headgear to upper molars on reduced basis (at night, for instance) in conjunction with retainer to hold teeth in alignment Use functional appliance of activator- bionator type to hold both tooth position and occlusal relationship

62. Shapiro’s : Class II, Division 2 malocclusions demonstrated significantly greater ability to maintain intercanine width expansion compared with Class I and Class II, Division 1 treated malocclusions Arch length reduction in Class II, Division 2 was significantly less than in Class I and Class II, Division 1 during treatment and from pretreatment to 10 years postretention .

63. Retention After Class III Correction Relapse from continuing mandibular growth is very likely to occur and such growth is extremely difficult to control. Applying restraining force to mandible, as from a chincup , is not nearly as effective in controlling growth in a Class III patients. Chincup tends to rotate the mandible downward, causing growth to be expressed more vertically and less horizontally, and Class III functional appliances have the same effect.

64. If face height is normal or excessive after orthodontic treatment and relapse occurs from mandibular growth, surgical correction after growth has expressed itself In mild Class III problems, functional appliance or a positioner may be enough to maintain occlusal relationships during posttreatment growth.

65. Retention After Deep Bite Correction Control of the vertical Position of teeth in retention is as important as controlling alignment, especially in patients who had a deep bite or open bite initially. L ower incisors contact palatal acrylic of upper retainer, while upper incisors contact facial surface of lower retainer. This prevents incisor eruption that would lead to return of excessive overbite

66. Retention After Anterior Open Bite Correction 17-year-old has an anterior open bite. 5 mm of overjet with an end-on molar severe crowding of mandibular incisors. Relapse of this type is associated with downward and backward mandibular rotation and eruption of upper posterior teeth during post-treatment growth The incisor crowding is due to uprighting and lingual repositioning of the incisors as the mandibular rotation thrusts them into the lower lip.

67. Relapse into anterior open bite can occur by any combination of depression of the incisors and elongation of the molars. Patient with severe open bite problem is particularly likely to benefit from having conventional maxillary and mandibular retainers for daytime wear, and an open bite bionator as a nighttime retainer, from the beginning of the retention period.

68. High-pull headgear to the upper molars with standard removable retainer to maintain tooth position, is one effective way to control open bite relapse. Appliance with bite blocks between posterior teeth that creates several millimeters of jaw separation ( an open bite activator or bionator ) Lower or lingual holding arch (LHA) Transpalatal arch (TPA) Hawley bite block can be used as retainer.

69. Retention of Lower Incisor Alignment Retainer in lower incisor region is needed to prevent crowding from developing, until growth has declined to adult levels. orthodontic retention should be continued, at least on a part-time basis, until third molars have either erupted into normal occlusion or have been removed.

70. The implication of this guideline, that pressure from developing third molars causes late incisor crowding, is almost surely incorrect. (prolonged retention needed in growing patients Retain lower incisor alignment until mandibular growth has declined to adult levels (i.e., until the late teens in girls and into the early 20s in boys

71. Timing of Retention: Summary Retention is needed for all patients who had fixed orthodontic appliances to correct intra-arch irregularities. It should be: Essentially full-time for first 3 to 4 months, except retainers should be removed while eating (unless periodontal bone loss or other special circumstances require permanent splinting) . Continued on a part-time basis for at least l2 months , to allow time for remodeling of gingival tissues If significant growth remains, continued part-time until completion of growth.

72. Retention planning divided into three categories Depending on the type and extent of retention treatment instituted: (1) limited retention (2) Moderate retention in terms of time and appliance wearing (3) permanent or semipermanent retention.

73. Limited retention Corrected crossbites Dentitions that have been treated by serial extraction . Corrections achieved by retardation of maxillary growth , dental or skeletal, after growth period Dentitions in which maxillary and mandibular teeth get separated to allow for eruption of teeth previously blocked out

74. Class I nonextraction cases(protrusion and spacing of maxillary incisors). Class I or Class II extraction cases Corrected deep overbites in Class I or Class II malocclusions Early correction of rotated teeth to their normal positions. Cases involving ectopic eruption of teeth or presence of supernumerary teeth (fixed or permanent retentive device, such as bonded lingual retainers) Corrected Class II, Division 2 malocclusion generally requires extended retention to allow for adaptation of musculature. Moderate retention

75. Expansion cases particularly in mandibular arch G eneralized spacing cases Instances of severe rotation, particularly in adults, or severe labiolingual malposition may require permanent retention, as provided by lingual bonded retainers. Spacing between maxillary central incisors in otherwise normal occlusions sometimes requires permanent retention, particularly in adult dentitions Permanent or semipermanent retention

76. RELAPSE

77. RELAPSE Soft tissue Skeletal Functional Surgical

78. Failures in retention leading to relapse Failure to remove the cause of malocclusion. Incorrect diagnosis and treatment planning. Lack of normal cuspal interdigitation . Arch expansion Incorrect axial inclinations. Failure to manage rotations- over rotation Tooth size disharmony- interproximal grinding

79. Trabecular and cortical bone as risk factors for orthodontic relapse . To evaluate whether the amount or the structure of mandibular bone affects the potential for mandibular incisor relapse Sixty relapse and 263 stable subjects were identified. Mandibular cortical thickness measured on both panoramic and lateral cephalometric radiographs was used to assess the amount of mandibular bone These results indicate that patients with thinner mandibular cortices are at increased risk for dental relapse.

80. Bishara et al (1989AJO and 1996 AO) : Evaluated changes in lower incisor between 12 and 25 years and again at 45 years – findings indicated : Increase in tooth size arch length discrepancy with age – consistent decrease in arch length. Average changes 2.7mm in males; 3.5mm in females. Similar findings by Lundstrom (1968) Sinclair and Little (1983 AJO) Little et al (1981AJO) observed that 90% of extraction cases that were well treated orthodontically ended up with an unacceptable lower incisor crowding.

81. RETAINERS Retainer- An appliance used to hold teeth in position after orthodontic treatment.

82. Hawley Retainers Removable Wraparound Retainers Spring Retainers Modified Functional Appliances as Active Retainers

83. Removable Appliances as Retainer Hawley Retainers M axillary premolar extractions A nterior bow soldered to Adams clasps on f irst molars so that extraction site is held close patient whose canines were facially positioned before treatment, wire extends across canines is soldered to anterior bow

84. wraparound outer bow soldered to C-clasps on second molars provides a way to avoid interference retainer wire crosses occlusion Moore design Control of second premolar and extraction site Canine-to-canine wraparound distally on lingual only to central groove of first molar Mandibular retainer

85. Removable Wraparound Retainers Advantage Esthetic Periodontal breakdown requires splinting the teeth together Disadvantage Less comfortable Not effective in maintaining overbite correction canine-to canine clip-on retainer used to realign irregular incisors, if mild crowding has developed after treatment prevent re-rotation of maxillary incisor

86. Positioners as Retainers Maintains occlusal relationships as well as intra-arch tooth positions. Patient with tendency toward Class III relapse, a positioner made with jaws rotated downward and backward Gingival stimulation Positioner does not make a good retainer

87. The major problems are: Difficulty wearing a positioner full-time so inability to control intra-arch alignment Positioners tend to be worn less than 4 hours per day after first few weeks, they are reasonably well tolerated by most patients during sleep. It not retain incisor irregularities and rotations Overbite tends to increase

88. Fixed Retainers Canine-to-canine retainer in lower arch is excellent way to maintain alignment. lt contains carrier to hold it in position while being bonded. Design with wire loops on canines to provide retention when retainer is bonded. Bonded canine-to-canine retainer, with retention pads in place.

89. Bonded wire used to maintain alignment of maxillary teeth that were severely displaced initially (as in Class II division 2) or keep a maxillary diastema closed. A lighter wire (r7.5 or r9.5mil twist) should be used. Maintenance of a severe rotations

90. 7.5mil twist wire contoured to fit W ire retainer is held in place with dental floss passed around the contact composite resin is flowed onto the cingulum of the teeth, over the wire ends. Maintenance of a maxillary central diastema

91. A-splint retainer Maintain space for eventual replacement of missing second premolar. Shallow preparation made in enamel of marginal ridges adjacent to extraction site 21 x 25wire, stepped down away from occlusion Alternative design W ire contoured so that flossing is not impeded, and bonded attachment areas also serve to keep bite from deepening

92. Active Retainers Realignment of irregular Incisors: Spring Retainers

93. Correction of Occlusal Discrepancies: Modified Functional Appliances as active retainers Activator or bionator as an active retainer is indicated if not more than 3 mm of occlusal correction is needed

94. REFERENCES Principles of retention in Orthodontia. Calvin Case. AJO Nov 1920. Logic of modern retention procedures. Kaplan. AJO April 1988 Changes in mandibular anterior alignment 10 to 20yrs post retention. Little, Riedel, Artun . AJO May 1988 Trabecular and cortical bone as risk factors for orthodontic relapse . Lothe et al AJO 2006 Willian R. Profitt 6 th edition Graber vanasdal 6 th edition