Preventive & Interceptive Orthodontics Basics

Preventive & Interceptive Orthodontics , Pediatric Dentistry

1. Preventive & Interceptive Orthodontics DR SIMRAN VANGANI Pg ii , Dept . of paediatric & preventive dentistry

2. Preventive orthodontics Preventive orthodontic procedures are aimed at elimination of factors that may lead to malocclusion, while interceptive orthodontics is undertaken at a time when the malocclusion has already developed or is developing. Preventive and interceptive orthodontics are the two phases of orthodontics that is best practiced in a developing stage. It involves the various diagnostic and the treatment procedures instituted to prevent the onset of malocclusion. 2

3. Preventive orthodontics according to Graber (1966) can be defined as the action taken to preserve the integrity of what appears to be normal occlusion at a specific time . Proffit and Ackerman (1980 ) defined Preventive orthodontics as the prevention of potential interference with occlusal development. Preventive orthodontics involves the procedures undertaken to prevent the developing of malocclusion from being manifested. Whereas the interceptive orthodontic procedures are taken after malocclusion has already set in. It is concerned at reducing the severity or elimination of the malocclusion before corrective measures are applied. Thus, the key difference between prevention and interception lies primarily in the timing of intervention. 3

4. Aims of preventive orthodontics - To achieve: Permanent dentition with all teeth in good alignment and contacts anatomically compatible with a healthy periodontium. Dental arches well related in all three planes of space with an optimal intercuspation that is substantially identical in both centric occlusion and centric relation. Stability between skeletal, dental and muscular components. 4

5. Procedures undertaken in preventive orthodontics Parent education Caries control Care of deciduous dentition Extraction of supernumerary teeth Occlusal equilibrium Maintenance of quadrant-wise tooth shedding time table Management of ankylosed tooth Management of abnormal frenal attachments Checkup for oral habits Prevention of damage to occlusion, for example, Milwaukee braces Management of deeply locked first permanent molar Space maintenance 5

6. Education of the parents- Parent counselling, though the most neglected, is the most effective way to practice preventive orthodontics. Parental counselling may be divided into: 1. Prenatal counseling 2. Postnatal counseling 6

7. Prenatal Counselling- This is the most effective time to get across to the expecting parents. Prenatal counselling may involve the following: The importance of oral hygiene maintenance by the mother. Recent studies have indicated a possible correlation between poor oral hygiene and premature births. The expecting mother should be educated on matters such as nutrition to provide an ideal environment for the developing foetus. They are advised to have natural foods containing calcium and phosphorous, e.g., milk products, egg, etc, especially during 3rd trimester, as they would allow adequate formation of deciduous teeth crowns. Genetic counselling is carried out in cases with families having genetic predisposition for hereditary diseases. 7

8. Postnatal Counselling- It should be advocated along with the clinical examination of the child. This is divided into- Six months to one year of age : These include instructions given to the parent regarding the predental care of the child before the eruption of any teeth. The mother should be educated on proper care and nursing of the child. The mother should be stressed about the importance of mother's milk over bottle-fed milk. In case of bottle-feeding, the mother should be educated about the selection of nipple and proper positioning of the bottle in the mouth. Physiologic nipples which permit suckling should be advised. The mother is also advised against the prolonged use of pacifiers and sweetening solutions in bottle which can have a detrimental effect on dentition. They are educated about the teething problems such as general irritability, loss of appetite, diarrhoea, circumoral rash that are possible in teething stage. Brushing with the help of a finger during bathing should be introduced. Cleaning of the deciduous dentition with a clean, soft cotton cloth dipped in warm saline is also recommended, to prevent the initiation of nursing or rampant caries. 8

9. Two years of age Three years of age Bottle feeding if previously initiated should never be given as pacifiers during sleep. Bottle feeding to be withdrawn completely by 18-24 months of age. These would decrease the chances of initiation of decay and the potential for nursing caries. Brushing to be initiated post-breakfast and post dinner. Clinical examination to assess any incipient decay and eruption status of teeth is done. Generally, the full complement of deciduous dentition should have erupted by now. Dentition should be assessed for molar and canine relationships and presence of any discrepancies away from the normal should be noted, e.g., unilateral cross- bite, supernumerary teeth, missing teeth, fused teeth, etc. The child should be on 3 square meals a day. Oral habits such as thumb sucking, lip sucking, mouth breathing and their effects on the development of occlusion should be considered. Parents should be informed accordingly. Child to be encouraged to begin brushing on his own at least once a day . 9

10. Five to six years of age: Parents to be informed about: a. The initiation of exfoliation of deciduous teeth and that it would go up to 12-13 years of age. b. The need for constant review and recall on a regular basis. c. In case of extraction of deciduous teeth due to decay the need, advantages and importance of space maintainers. 10

11. Caries Control- Caries involving the proximal surface of deciduous teeth if not restored at the earliest may lead to loss of arch length by movement of adjacent teeth into that space. The most effective tool in detecting proximal caries is the bitewing radiograph. Once detected, the affected teeth should be restored immediately to their proper mesiodistal dimension so as to prevent loss of arch length. Caries initiation can also be prevented by diet counselling, topical fluoride application, and pit and fissure sealants 11

12. Care of deciduous dentition- All efforts should be made to prevent early loss of deciduous dentition by way of prevention of caries and timely restoration of carious teeth. Simple preventive procedures such as proper and timely application of topical fluoride or pit and fissure sealant application help in preventing caries. Deciduous teeth by themselves act as the best natural space maintainers, which not only maintain the space for their succeeding permanent teeth but also guide the latter teeth into their proper position in the dental arches. 12

13. Extraction of Supernumerary Teeth- Supernumerary and supplemental teeth can interfere with the eruption of nearby normal teeth. They can deflect adjacent normal teeth to erupt in abnormal positions, e.g., presence of a mesiodens in the midline prevents the two maxillary central incisors from contacting each other. Likewise a supernumerary premolar may deflect the normal premolar in either buccal or lingual direction. These supernumerary teeth should be extracted before they derange the establishment of normal occlusion. Their reported prevalence ranges between 0.3% and 0.8% in the primary dentition and 0.1−3.8% in the permanent dentition with more predilections for males and the anterior region. 13

14. Management of ankylosed teeth- Ankylosis is a condition characterized by direct approximation of cementum and alveolar bone without intervening periodontal membrane in a small area or the whole of the root surface. In the resting stages of resorption, excessive repair tissue may be deposited until the root becomes fused to the adjacent bone. This may prevent the tooth from being shed and the permanent successor from erupting or deflect them to erupt in abnormal locations. These ankylosed teeth should be clinically as well as radiographically detected and removed surgically at an appropriate time to permit unimpeded eruption of permanent teeth. 14

15. Occlusal equilibration Occlusal equilibration is performed as preventive ,interceptive and corrective orthodontic procedures. It is the systematic reshaping of the occlusal anatomy of teeth to minimize or eliminate the role of occlusal interferences in reflexly determined mandibular positions. Occlusal equilibration is done more during active growth. Functional shifts which lead to pseudoclass III and crossbites should be checked and eliminated. Overextended restorations may cause occlusal prematurities . They have to be reduced. Any abnormalities in shape which lead to occlusal derangement should be trimmed e.g. Epstein pearls , extra cusps. 15

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17. Maintenance of Quadrant-Wise Tooth Shedding Timetable There should not be >3 months difference between the shedding of deciduous teeth and eruption of permanent teeth in one quadrant as compared to other quadrants. Delay in eruption may be due to any one of the following reasons: Presence of over retained deciduous teeth/roots Presence of supernumerary tooth Cysts and tumors of the jaw Overhanging restoration in deciduous teeth Fibrosis of gingiva Ankylosis of deciduous teeth Absence of permanent tooth bud. 17

18. Extraction of deciduous teeth Extraction of retained deciduous tooth is done when indicated by the state of development of permanent successor. Sometimes removing primary tooth early allows permanent teeth to align better. Early extraction of primary teeth also prevents permanent teeth from erupting into abnormal location. 18

19. Management of abnormal frenal attachments The presence of a thick and fleshy abnormal maxillary labial frenum that is attached relatively low may cause the development of midline diastemas/excess spacing between the teeth, which in turn may not allow the eruption of succedaneous teeth. Presence of interdental notching of bone in a periapical radiograph confirms a thick frenal attachment. Surgical correction of the high frenal attachment is advised. Ankyloglossia or tongue-tie due to short lingual frenum may result in abnormalities of speech and swallowing. A lingual frenectomy is done to relieve the tongue-tie. 19

20. Oral habits check-up and educating patients and parents Abnormal oral muscular habits such as finger and thumb sucking, nail biting, tongue thrusting and lip biting should be identified and stopped early before they transform into compulsive habits. Prevention of the development of these habits begin with proper nursing care and use of physiological nipples that simulate normal suckling and swallowing pattern. In oral habits such as thumb/digit/lip sucking - the child can be distracted from indulging in the same. In mouth breathing-the child can be given adequate medical attention, regarding recurrent upper respiratory tract infection. 20

21. Deeply locked permanent first molars Sometimes a permanent molar may erupt in a slightly mesial direction and get locked under distal side of the deciduous second molars This also happens in patients with a prominent distal bulge on deciduous second molars which prevents the normal eruption of the first permanent molars. Disking of the distal surface of the second deciduous molar relieves this lock and first permanent molar is guided into proper position. Slightly locked permanent first molar usually erupts without treatment. Passing a ligature wire or separators interdentally frees the slight lock. 21

22. Preventing Milwaukee Brace Damage Milwaukee brace is an orthopedic appliance used for the correction of scoliosis. This appliance exerts tremendous force on the mandible and the developing occlusion leading to retardation of mandibular growth and possible deformities. Specially designed intraoral splints, activators, positioners, and dentofacial orthopedic appliances may prevent malocclusion or at least reduce the deleterious effects. 22

23. Space Maintainers Premature loss of deciduous teeth can cause drifting of the adjacent teeth into the space. It can result in abnormal axial inclination of teeth, spacing between teeth and shift in the dental midline. This prevents the normal eruption path of permanent teeth leading to malocclusion . So corrective procedure may require some type of passive space maintainers, active tooth guidance, or a combination of both, depending on the present problem 23

24. Interceptive Orthodontics 24

25. Definitions: Interceptive orthodontics is defined as that phase of the art and science of orthodontics employed to recognize and eliminate potential irregularities and malpositions of the developing dentofacial complex ( T.M. Graber) American Association of Orthodontists (1969 ) defined it as that phase of science and art of orthodontics employed to recognize and eliminate the potential irregularities and malpositions in the developing dentofacial complex. According to Ackerman and Proffit (1980), interceptive orthodontics can be defined as “Elimination of existing interferences with the key factors involved in the development of the dentition.” 25

26. Various procedures under interceptive orthodontics Serial Extractions Control of Abnormal Habits Space regaining Developing Anterior Crossbite Interception of skeletal malrelations Removal of soft or hard tissue 26

27. Serial Extraction Serial extraction can be defined as the correctly timed planned extractions of certain deciduous and permanent teeth in mixed dentition cases with dentoalveolar disproportion i . e., tooth size-arch length discrepancy (TSALD) in order to: Allow unerupted teeth to guide themselves into improved positions. For example, deciduous first molar is extracted to speed eruption of first premolar, when root development of the first premolar is halfway Lessen the period of active mechanical appliance therapy or eliminate it. 27

28. History The concept was initiated way back by Bunon (1743). The catchy term serial extraction was coined by Kjellgren of Sweden ( 1929). He used the term serial extraction to describe a procedure where some deciduous teeth followed by permanent teeth were extracted to guide the rest of the teeth into normal occlusion. The serial extraction procedure was popularized by Hayes Nance ( 1940), who has been called the ‘ father of serial extraction' philosophy in the United States. He termed it 'planned and progressive extraction.’ Rudolph Hotz of Switzerland in 1970 called such a procedure as 'active supervision of teeth by extraction. ' 28

29. Serial extraction is based on two basic principles : a . Reduction of tooth material : The discrepancy between the excessive tooth material and the arch length can be minimized by selective extraction of certain teeth. The excessive tooth material is thus reduced and matches with that of a given arch length, thereby guiding the remaining teeth into a normal alignment. b. Physiologic tooth movement Human dentition will be in a state of neutral zone under the influence of forces acting on it from different directions. Whenever a tooth is lost or extracted the adjacent teeth drift physiologically towards this extraction space. This physiological movement is more marked in mesial direction but can also occur in distal direction. Thus, by selective extraction of certain teeth, the adjacent teeth which are erupted or in the process of eruption are guided by the natural forces into the space left over by extraction of the teeth. 29

30. Indications Arch length deficiency of more than IO mm as compared to the tooth material is the most important indication for serial extraction. Class I malocclusion showing harmony between skeletal and muscular system In cases where growth is not enough to overcome tooth material and arch length discrepancy Patients with straight profile and pleasing appearance 30

31. ` Tooth size-arch length deficiency (TSALD) is indicated by the presence of one or more of the following features: Absence of physiologic spacing. Premature forced exfoliation of the unilateral or bilateral deciduous canines with the eruption of the permanent lateral incisors. Midline shift in the case of unilateral premature loss of primary canines. Malpositioned or impacted lateral incisors that erupt palatally or lingually out of the arch. Markedly irregular or crowded upper and lower anteriors . The teeth erupting too far labially and lingually out of arch and commonly referred to as Blocked out of arch. Localized gingival recession in the lower anterior region on one or more teeth is a characteristic feature of arch length deficiency. 31

32. Ectopic eruption of maxillary first molar resulting in premature exfoliation of primary second molar. Mesial migration of buccal segment. Abnormal eruption pattern and sequence. Splaying of upper and lower teeth as a result of crowding. Ankylosis of one or more teeth. 32

33. Diagnostic procedure The diagnostic exercise prior to treatment should involve comprehensive assessment of the dental, skeletal and soft tissues. It includes: ■ Clinical examination ■ Occlusion study -model analysis ■ X-rays IOPA, OPG, cephalograms with cephalometric tracings ■ Mixed dentition analysis ■ Facial photographs Study model analysis should be carried out to determine the arch length discrepancy. The skeletal tissue assessment should involve comprehensive cephalometric examination to study the underlying skeletal relation. The eruption status of the dentition is evaluated from an OPG. The soft tissue assessment by clinical examination and cephalograms helps in the diagnosis. Serial extraction is generally undertaken in patients exhibiting harmonious soft tissue pattern. 33

34. Rules to be Followed 1. There must be Class I molar relationship bilaterally with a normal neuromuscular balance. 2. The facial-skeletal relation must be balanced anterior-posteriorly, vertically and mesiodistally. 3. Harmonious soft tissue relation. 4. Discrepancy should be at least 5 mm in all quadrants 5. Dental midline should coincide. 6. There must be neither open bite nor deep bite 34

35. Procedure- A number of methods or sequences of extraction have been described. Three of the popular methods are: Dewel 's method (C -D - 4) Tweed's method (D - 4 - C) Nance method (D -4 - C) 35

36. Dewel’s Method Dewel has proposed a 3-step serial extraction procedure. The sequence proposed by Dewel is the extraction of C ➔ D ➔ 4. Step I-Extraction of deciduous canines : In the first step, the deciduous canines are extracted and the resulting space is utilized for aligning the crowded incisors. This step is carried out at 8-9 years of age. The resorption of the deciduous canine by permanent lateral incisor can provide an indication to the same (age 8.5 years ). Step 2-Extraction of the first deciduous molars : A year later, the deciduous first molars are extracted so that the eruption of first premolars is accelerated. When more than half of the root length of unerupted premolar is completed (9½ years), the deciduous first molar may be extracted to promote the eruption of the first premolar. By this time the anterior crowding would have resolved. Step 3-Extraction of permanent first premolar : At around 11 years of age the permanent first premolar is extracted to permit the eruption of permanent canines in its place. 36

37. Tweed’s Method The sequence followed is D4C. This method involves the extraction of the deciduous first molars around 8 years of age. Once the permanent premolar cuts through the socket, it is extracted with the deciduous canines simultaneously. Removal of the first primary molars before the primary canines is sometimes advocated to promote the earlier eruption of the first premolars. This sequence of extraction is of interest only in the lower arch because the maxillary first premolars usually erupt ahead of the canines. 37

38. Nance Method The sequence of extraction involves initial extraction of the deciduous first molars followed by the extraction of the first premolars and the deciduous canines. It is similar to Tweed's technique. 38

39. Timely Extraction This is similar to serial extractions wherein sequential removal of deciduous teeth is carried out, but differs in that no permanent teeth are removed. The term timely extraction has been recommended by Stemm . 39

40. Control of Abnormal Habits Habits are referred to certain actions involving the teeth and other oral or perioral structures which are repeated often enough to have a profound and deleterious effect on the dentofacial structures. These deleterious oral habits include thumb sucking, tongue thrusting and mouth breathing. 40

41. Space Regaining If a primary molar is lost early and space maintainers are not used, a reduction in arch length by mesial migration of the first molar is expected. In such cases the space lost by mesial movement of the first molar can be regained by distalizing it ™ The space regaining procedures are preferably undertaken at an early age prior to the eruption of second molar. Causes of the Mesial Tipping/Drifting of Molars ■ Extensive carious lesions ■ Ectopic eruption ■ Premature extraction of primary molars-without any space maintenance 41

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43. DEVELOPING ANTERIOR CROSSBITE "The best time to treat a crossbite is the first time you notice .“ Anterior crossbite is a condition characterized by abnormal labiolingual relation (reverse overjet) of one or more maxillary anterior teeth to the opposite mandibular teeth. 43

44. Anterior crossbite should be treated as early as possible when recognized for the following reasons : A. Anterior crossbites, if not intercepted and treated at an early stage, may progress from a simple orthodontic problem to a skeletal malocclusion. The single-tooth crossbites during growth phase may result in asymmetrical face. B. The anterior crossbite present in the mixed dentition may get worsened in the permanent dentition stage and is detrimental to the periodontal structures as well as temporomandibular joint. 44

45. Anterior crossbites can broadly be classified as: Dentoalveolar anterior crossbites Functional anterior crossbites Skeletal anterior crossbite 45

46. Dentoalveolar Anterior Crossbite Anterior crossbite in which one or more maxillary anterior teeth are lingually displaced in relation to the mandibular anterior teeth. The etiological factors are local and dental in nature and many a times is due to over-retained deciduous teeth that deflect the erupting permanent teeth palatally . This type of anterior crossbite is often manifested as single-tooth crossbite with upper central incisor locked in most cases. Developing crossbites can be prevented from perpetuating "into full-fledged crossbites by effective use of tongue blade therapy. They can be intercepted with Catalan's appliance and double cantilever springs with posterior bite plate. 46

47. Tongue blade therapy : The blade is placed in such a manner that it rests on the mandibular incisors opposing the tooth in crossbite, and the patient is asked to bite with a constant pressure on the tongue blade. If there is adequate space for the tooth in crossbite to be moved into its correct position, the tooth can be guided with the help of the tongue blade . The proper use of the tongue blade for an hour or two a day for 10–14 days is sufficient to deflect the lingually erupting tooth into a proper relationship. 47

48. Catalan’s appliance is used to correct the crossbite of young patients whose permanent molars have not erupted and deciduous molars are lost. It is used on lower anteriors where the appliance makes use of muscle forces and guides erupting tooth in normal positing. When appliance is worn, the teeth can come in contact only in the anterior region during masticatory functions and hence correct the crossbite. It is constructed at 45° angulation on the lower incisors by acrylic or cast metal. A removable appliance of this type requires nearly fulltime wear to be effective and efficient. It is also possible to tip the maxillary incisors forward with a 2 × 4 appliance (2 molar bands, 4 bonded incisor brackets) and fixed mechanotherapy . This may be the best choice for a somewhat older mixed dentition patient with crowding, rotations and more permanent teeth in crossbite. 48

49. Functional Anterior Crossbite These types of crossbite result from the functional shift of the mandible. The presence of occlusal prematurities deflects the mandible into a more forward path of closure. These are commonly seen in pseudo-Class III type of malocclusion . These are to be treated by eliminating the occlusal prematurities . If left untreated they may transform into true skeletal cross bites. 49

50. Skeletal Anterior Crossbite Anterior crossbites of this type usually are the manifestations of underlying skeletal discrepancies in growth of maxilla or the mandible. This type of crossbite usually involves the whole segment instead of one or two teeth This type of crossbite is seen in Class III skeletal conditions characterized by relative maxillary skeletal retrognathism/ hypoplasias or mandibular prognathism or both in severe cases. These type of crossbites are best intercepted by growth modulation procedures by use of myofunctional or orthopedic appliances, which brings about harmony between maxillary and mandibular skeletal bases. 50

51. INTERCEPTION OF SKELETAL MALRELATIONS The severity of skeletal malocclusion can be minimized if diagnosed at an early age and intercepted accordingly. The different myofunctional and orthopedic procedures taken up during active growth period to intercept the abnormal growth pattern of the jaw bases is known as Growth modulation or Growth modification. It is aimed at achieving a harmony in maxilla mandibular skeletal bases. 51

52. Interception of Class II Malocclusions This occurs as a result of either excessive maxillary growth, deficiency in mandibular growth, or a combination of both. Maxillary growth can be restricted by use of face bow with head gear. Mandibular deficiency is usually treated by myofunctional appliances, e.g. FR-II Interception of class III malocclusions This develops as a result of mandibular prognathism, maxillary retrognathism or combination of both. Chin cup with head gear are used to restrict mandibular growth and maxillary deficiency can be intercepted by orthopedic appliance, such as face mask or by means of myofunctional appliances like FR-III. 52

53. Removal of soft or hard tissue impediments to the pathway of eruption Retained Deciduous Tooth/Teeth – Generally, retained deciduous teeth are observed in the mandibular anterior region, with the permanent teeth erupting lingually. This condition is also observed in the maxillary canine region with the permanent teeth erupting labially/buccally. The retained deciduous tooth should be extracted. 53

54. Fibrous/Bony Obstruction of the Erupting Tooth Bud – If the contralateral tooth fails to erupt even after 3 months, there should be a cause for concern and a radiographic assessment, therefore, becomes mandatory. The delayed eruption of permanent tooth which fails to erupt in time, may be stimulated to erupt by surgical exposure of the crown. Any impeding soft tissue has to be excised and bone barrier overlying the crown of the unerupted tooth is removed. The soft or hard tissue excision is done in such a way so as to expose the greatest diameter of the unerupted tooth crown or slightly larger. A zinc oxide-eugenol dressing is recommended for a period of2 weeks postsurgically . 54

55. References Shoba Tandon. Textbook of pedodontics, 3 rd ed. Gardiner, Leighton, Luffingham , Ashima Va l i athan , Orthodontics for dental students, 4'h ed E Moyers, Handbook of Orthodontics, 4th ed., Year Book Medical Publ ishers , Inc., 1988 Ackerman JL, Profitt WR. Preventive and interceptive orthodontics: A strong theory proves weak in practice. Angle Orthod 1980;50:75-86. Textbook Of Orthodontics by Gowri Shankar Textbook of Pediatric Dentistry, 4th Edition Nikhil Marwah McDonald and Avery's Dentistry for the Child and Adolescent Orthodontics The Art And Science By Bhalajhi 55

56. Thankyou 56