Eruptive anomalies /certified fixed orthodontic courses by Indian dental academy


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Eruptive anomalies /certified fixed orthodontic courses by Indian dental academy

  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education
  5. 5. Tooth eruption involves the migration of the teeth from a nonfunctional position within the bone to a functional position in the jaw. In orthodontic practice, it is inevitable that one will encounter eruptive abnormalities such as impacted, ectopically erupting, transposed, congenitally missing, and supernumerary teeth. The treatment plans were developed to address these anomalies and soft tissue reactions to the movements are considered.
  6. 6. Impaction Impaction is defined as the total or partial lack of eruption of a tooth well after the normal age for eruption. An impacted tooth may appear blocked by another tooth, bone, or soft tissue, or displaced so that it cannot erupt . Descending order of occurrence: maxillary and mandibular third molars, maxillary cuspids, second premolars, maxillary central incisors, mandibular cuspids, second molars, lateral incisors, and first premolars.
  7. 7. Bishara and associates summarized Moyer's theory that impaction is caused by: 1. Primary causes: A. Rate of root resorption of deciduous teeth. B. Trauma of the deciduous tooth bud. C. Disturbances in tooth eruption sequence. D. Availability of space in the arch. E. Rotation of tooth buds. F. Premature root closure. G. cleft area in persons with cleft palate. 2. Secondary causes: A. Abnormal muscle pressure. B. Febrile diseases. C. Endocrine disturbances. D. Vitamin D deficiency. Other pathological causes for impacted teeth are cysts, tumors and odontomes.
  8. 8. CLINICAL EVALUATION. (1) Delayed eruption of the permanent teeth and prolonged retention of the deciduous teeth beyond 14 to 15 years of age (2) absence of a normal labial bulge through intraoral palpation of the alveolar process (3) presence of a palatal bulge, delayed eruption, distal tipping, or migration (splaying) of the adjacent teeth. SEQUELAE OF IMPACTION Shafer suggested the following sequelae: (a) labial or lingual malpositioning of the impacted tooth, (b) migration of the neighboring teeth and loss of arch length, (c) internal resorption, (d) dentigerous cyst formation, (e) external root resorption of the impacted tooth, as well as the neighboring teeth, (f) infection particularly with partial eruption, (g) referred pain,
  9. 9. RADIOGRAPHIC DIAGNOSIS OF IMPACTED TEETH PERIAPICAL RADIOGRAPHS It is two dimensional and gives no information in buccolingual plane. To evaluate the position of the canine buccolingually, a second periapical film should be obtained by one of the following methods. a) Buccal object rule. If the vertical angulation of the cone is changed by approximately 20° in two successive periapical films, the buccal object will move in the direction opposite the source of radiation. On the other hand, the lingual object will move in the same direction as the source of radiation.
  10. 10. b) Tube-shift technique or Clark's rule. Two periapical films are taken of the same area, with the horizontal angulation of the cone changed when the second film is taken. If the object in question moves in the same direction as the cone, it is lingually positioned. If the object moves in the opposite direction, it is situated closer to the source of radiation and is therefore buccally located.
  11. 11. OCCLUSAL RADIOGRAHS It depicts all the posterior and anterior standing teeth in cross section and provides buccolingual and mesiodistal information of the impacted teeth .A palatally placed tooth will appear within this arc of small circles. An angled tooth will show up in its elliptical oblique cross section representing a tilted long axis. Disadvantage:Relative height of the object cannot be made out.
  12. 12. EXTRAORAL RADIOGRAPHS: OPG gives a good scan of teeth in mesiodistal and vertical direction. Lateral cephalograms gives information regarding the vertical and anteroposterior position of the impacted tooth especially in cases of dilaceration. PA view defines the height and the buccolingual relationship. By combining these,three dimensional view is obtained.
  13. 13. CT SCANNING By viewing serial radiographic slices of the maxilla, the relation ship of the impacted tooth to the adjacent teeth in all three planes of space may be accurately assessed.
  14. 14. TREATMENT OPTIONS 1.Extraction of impacted tooth and movement of adjacent tooth in its position 2.Autotransplantation of impacted tooth 3.Prosthetic replacement of impacted tooth either with crown or with implant 4. Surgical exposure and placing a traction force to bring it into the arch Sufficient space is achieved by 1.Extraction of succedaneous tooth or some other tooth or teeth 2.Molar distalisation or expansion Once space is achieved ,surgical exposure of the tooth is performed
  15. 15. APICALLY REPOSITIONED FLAP The apically positioned flap is a split-thickness pedicle reflected from the edentulous area (lateral to the area in the case of an impaction). The flap was sutured apically to the periosteum, leaving one-half to two-thirds of the crown uncovered. Negative esthetic effects, such as increased clinical crown length, increased width of attached tissue, gingival scarring, and intrusive relapse were evident in the teeth treated with an apically positioned flap.
  16. 16. CLOSED ERUPTION TECHIQUE The crown of the tooth is exposed, an attachment is fixed to it, and the flap is sutured back over the crown. ADVANTAGES - produces the best esthetic and periodontal results. DISADVANTAGE - High profile brackets may lead to button holing or breakdown of overlying tissue
  17. 17. If the tooth is impacted in the middle of the alveolus or high in the vestibule near the nasal spine, the closed-eruption technique may be the treatment of choice. If the tooth requires more attached gingiva or is displaced lateral to the edentulous area, an apically positioned flap may be the best choice.(Johnston,Gaulis) Vanarsdall and Corn suggested that keratinised tissue be placed to cover CEJ and 2-3mm of crown as the new gingival attachment prevents the marginal bone loss and the gingival recession.The attached gingival is made available by apically repositioned flap, a laterally repositioned pedicle graft , or a free gingival graft.
  18. 18. TUNNEL PROCEDURE ( by Cresicini) The extraction of the deciduous tooth provided a natural osseous tunnel, which was easily extended by drilling, to reach the cusp of the impacted tooth. Traction through the tunnel ensured an eruption path that closely follows the physiologic pattern.
  19. 19. INDICATION Deep infraosseous teeth associated with persistent deciduous teeth. ADVANTAGE Physiologic attachment levels without gingival recession and adequate amounts of gingiva may be obtained. No gingival augmentation procedure is required and the natural appearance of the tissues may be preserved.
  20. 20. METHODS OF ATTACHMENT In the surgical exposure of an impacted tooth, only enough bone should be removed to allow for the placement of a bracket and that during the procedure the CEJ should not be intentionally exposed. Different methods of attachment to the impacted tooth have been suggested, including lasso wires, threaded pins,orthodontic bands, simple eyelet, crowns, wire ligatures, chain links, auxillary springs directly bonded brackets and magnets.
  21. 21. MODE OF TRACTION By using ligature wire ,elastic thread, elastomeric chains, coil springs, NiTi archwire, Ballista spring, Killroy spring, Cantilever spring ANCHOR UNIT It is necessary to develop a rigid anchor base against which to pit the forces required to reduce impaction.Headgear ,intramaxillary elastics, modified removable appliances and soldered palatal or lingual bars also provides a solid anchorage base. RETENTION PROTOCOL Fibrotomy and bonded fixed retainers are necessary
  22. 22. Dentigerous cysts involved with the impacted teeth Large dentigerous cysts in the mixed dentition are generally associated with jaw deformity and dislocation of one or more germs of permanent teeth. TREATMENT OPTIONS Treatment by enucleation will result in incomplete removal of the epithelium around the neck of the tooth crown or accidental dislodgement of the tooth during the curettage process. Marsupialization involves opening the cyst into the oral cavity at its most superficial point and maintaining the patency of this orifice with the fusion of the cut linings of the cyst and the oral mucosa. Any attempt to apply orthodontic traction to the tooth at this time will extrude ahead of the advancing bone, thereby weakening its bony and periodontal support..Orthodontic treatment is deferred only after enough filling in of the bone takes place.
  23. 23. WHEN TO EXTRACT AN IMPACTED TOOTH (1)If it is ankylosed and cannot be transplanted (2)if it is undergoing external or internal root resorption, (3) if its root is severely dilacerated, (4) if the impaction is severe (5) if the occlusion is acceptable, without the impacted teeth (6) if there are pathologic changes (e.g., cystic formation, infection), and the patient does not desire orthodontic treatment
  24. 24. Incisor Impaction An impacted maxillary central incisor is more conspicuous to parents Typically, this occurs when the child is between 8 and 10 years of age CAUSE The incisor is prevented from erupting into the arch because of the presence of a heavy band of tissue physically obstructing eruption TREATMENT Treatment consists of surgically making a "window" in the tissue at the incisal edge of the tooth. This opening is packed with a periodontal dressing for 1 to 2 weeks so that the tissue does not heal back over the incisal edge,. The incisor tooth is then allowed to erupt through the opening.
  25. 25. Second Molar Impaction Incidence 3 in every 1000 mandibular second molars. The usual age at presentation is between 11 and 13 years More often than not, the mesial marginal ridge of the second molar is "caught" below the distal contact of the first molar. The methods of uprighting these impacted teeth include 1. surgical repositioning and orthodontic repositioning 2.extract the second molars and allowing the third molars to erupt in their place 3. autotransplantation;
  26. 26. SURGICAL UPRIGHTING Involves judicious amount of bone removed and exposure of the occlusal surface of the tooth with deliberate wedging of the tooth between the distal bone and the distal surface of the first molar tooth. Drawbacks Loss of vitality, stunted root formation, ankylosis, and resorption of the second molar Advantages quick and easy procedure with minimal morbidity and good long-term prognosis since the tooth is not removed from the socket, and in many cases the apical vessels probably remain intact.. TRANSPLANTATION There has also been very limited success in extracting the second molar and transplanting the third molar into the second molar socket probably because of the lack of bone remaining distal to the second molars. Pulpal calcification and degenerative changes has been noted with transplanted teeth.
  27. 27. ORTHODONTIC UPRIGHTING It is usually necessary to effect distalizing as well as eruptive forces. To optimize distalization, it is advantageous to remove the third molar teeth, if present.A variety of methods include separators, superelastic wire ,open coil springs, and segmental springs. In mild impactions, all that may be necessary is to "dislodge" the second molar from its trapped position under the distal bulge of the first molar. This can be accomplished either by a simple elastic separator or by using a twisted brass wire inserted around the contact point.
  28. 28. Mandibular second premolar CAUSE Crowding and space loss due to early extraction of the decidous predecessor Abnormal premolar orientation due to abnormal angulation of tooth germ Infraoccluded second decidous molars TREATMENT OPTIONS 1.Space created for the impacted tooth 2. A single rigid bar may be bonded or banded to the first premolar and molar tooth.The impacted tooth is directed with labial and extrusive force
  29. 29. Ectopic Eruption Ectopic eruption can be broadly defined as the emergenceof a tooth in a site different from its normal location, in all three planes of space. Canine Ectopic Eruption Incidence of approximately 0.9% to 2%. Females are affected more often than are males. Resorption is present in 12.5% of ectopically erupting canines. TREATMENT The clinician needs to decide whether the cuspid can be moved to its normal position without causing or exacerbating resorption of the adjacent teeth. If the latter is not possible, then canine extraction may be the best treatment
  30. 30. If the canine can be moved to its normal position without passing in close proximity to other tooth roots or is actually moved from the vicinity of a resorbing root, then orthodontically moving the tooth is likely to be the best option. If the amount of root structure resorbed by the ectopically erupting canine was significant to reduce the lifespan of the resorbed tooth, then it may be prudent to extract the resorbed tooth and allow the canine to erupt in the place of the extracted tooth.Prosthodontic treatment especially porcelain veneers are used.
  31. 31.
  32. 32. INTERCEPTIVE ORTHODONTICS Selective extraction of the deciduous canines as early as 8 or 9 years of age has been suggested by Williams as an interceptive approach to canine impaction in Class I uncrowded cases. Ericson and Kurol suggested that removal of the deciduous canine before the age of 11 years will normalize the position of the ectopically erupting permanent canines in 91% of the cases if the canine crown is distal to the midline of the lateral incisor. On the other hand, the success rate is only 64% if the canine crown is mesial to the midline of the lateral incisor
  33. 33. Ectopic Eruption of First Permanent Molar Teeth Local disturbance characterized by eruption of these teeth under the distal undercut of the second primary molars and failure of the first permanent molars to erupt to the normal occlusal plane. Seen more in children with clefts. Higher incidence in the maxilla (2% to 6%) than in the mandible (~0.2%). Two classes Reversible defines a situation in which the permanent molar can free itself from under the distal portion of the second deciduous molar. In the irreversible form, the permanent molar cannot free itself. .
  34. 34. CAUSES small maxilla, posteriorly positioned maxilla relative to cranial base, path of eruption of the maxillary first permanent molar, premature eruption of this tooth with inadequate anterior movement of deciduous dentition, mesiodistal widths of the maxillary first and second primary molars, asynchronization between eruption of the maxillary first permanent molar and tuberosity growth, and retarded eruption of the dentition. Genetic influence is also postulated using the width of the marginal ridge of the first permanent molar, was adapted from Harrison and Michal as follows: 0 normal or no sign of impaction 1 minimal lock or impacted less than half the width of the distal marginal ridge 2 moderate lock or impacted more than half the width of the distal marginal ridge but less than the width of the distal marginal ridge 3 severe lock or impacted more than the width of the distal marginal ridge CLASSIFICATION
  35. 35. SEQUELAE Ectopic eruption of the first permanent molar will result in premature exfoliation of the second deciduous molar with a resultant loss of arch length. The longer the impaction is continued, the more arch length will be lost and the more difficult it will be to move the permanent molar tooth from beneath the distal side of the deciduous molar tooth TREATMENT OPTIONS Should an unacceptable loss of arch length have occurred, space should first be regained and then maintained. The space can be regained by a removable appliance with a finger spring, headgear, bands on first permanent molar, and second or first deciduous molars with an open coil spring in between. These appliances may be useful regardless of whether the second deciduous molar required extraction.
  36. 36. If the second deciduous molar is kept in place, and its coronal mesialdistal length has been unaltered, it may serve as a space maintainer. However, if the second deciduous molar tooth has been lost, one of a number of devices can be used to maintain the space. These include, among others is, the band and loop appliance, a Nance appliance, a lingual holding arch, and a removable retainer.
  37. 37. Tooth Transposition Tooth transposition is the eruption of a tooth in a space normally occupied by another tooth.. Incomplete transposition is a condition describing an interchange in the positions of the crowns of two permanent teeth within the same quadrant of the dental arch, while the root apices remain in their relative positions. Complete transposition is a similar situation in which both the crowns and the entire root structure are transposed. Unilateral transposition on the left side is more frequent seen often in females and in the maxilla. Canine and first premolar transposition (55%) more often seen than canine and lateral incisor (45%). Mandibular tooth transpositions are seen less frequently Decreasing order of occurrence : canine-first premolar; canine lateral incisor; lateral incisor-central incisor; and canine-central incisor.
  38. 38. CAUSE Shapira and Kuftinec list the following: tooth buds interchange, retained deciduous canines, migration of the erupting canine, heredity, bone disease, and trauma to deciduous teeth in cases where dilaceration of the permanent incisor roots is found adjacent to transposed teeth Hitchin (1956), Platzer (1968), and Mader(1979) stated that it probably occurs as a result of change in the usual preeruptive path of the canine.Trauma to the deciduous dentition was suggested as the possible cause for transposition in the cases with dilacerated teeth adjacent to transposed teeth. In the mandible the distal migration of the lateral incisor appears to be the primary reason for the developing transposition. Genetic factors have been offered as an explanation to the anomaly. Bone disease,tumor or cyst, also may be responsible for the displacement of the single canine, causing its transposition
  39. 39. Characteristic features of maxillary canine and first premolars: 1.retained deciduous canine 2.permanent canine often blocked out buccally and mesio-labiall rotated 3.the transposed first premolar rotated mesio-palatally upto 90o 4.transitional crowding in the transposed area Characteristic feature of Maxillary canine and lateral incisor: 1retained deciduous canine 2.labially blocked out and often roated canine and lateral incisor 3.small lateral incisor and missing second premolars 4.Impaction of the canine and central incisor, most often on th transposition side. •
  40. 40. CLINICAL FEATURES of Mn.I2.C transposition severe distal tipping, displacement and rotation of the mandibular lateral incisor as it erupts ectopically into the area normally reserved for the sameside canine and first premolar. Later, the mandibular canine erupts transposed mesially to the ectopic lateral incisor. INTERCEPTIVE APPROACH When incipient transposition is detected early enough, interceptive treatment should be initiated to remove retained deciduous teeth and guide the ectopic tooth to its normal place in the arch. TREATMENT OPTIONS Generally it is preferable to move teeth to their correct positions in the dental arch. 1.alignment of teeth in their transposed positions 2. extraction of one or both transposed teeth, 3.orthodontic movement to their correct positions in the arch.
  41. 41. Transpositions in the maxillary arch In incomplete transposition, uprighting and rotating the involved teeth is most often required. To avoid root interference or resorption during treatment, and to prevent bony loss at the cortical plate of the labially positioned canine, the transposed tooth (premolar or lateral incisor) should first be moved palatally, enough to allow for a free movement of the canine to its normal place. Subsequently, the other transposed unit can be moved labially, back to its normal position in the arch.
  42. 42. Sometimes due to the difficulty of moving the roots past one another without causing other damage, these teeth are optimally treated in their transposed positions. They are orthodontically positioned as if they belong in the space in which they have erupted and made aesthetically more pleasing. , Transpositions in mandibular arch If the mandibular canine and lateral incisor have already erupted in their transposed position, correction to their normal position should usually not be attempted.
  43. 43. Transmigration of mandibular canines Displacement of teeth from one quadrant across the midline to the other side, referred to as transmigration Less than 20% of all transmigrating mandibular canines finally erupt and become transpositions; the rest of them remain as nonerupted, impacted teeth
  44. 44. Infraocclusion of permanent teeth Proffitt and Vig (1981) list the characteristics of primary failure of eruption as 1.posterior teeth only excluding incisors 2.some erupt and undergo submergence as in infraoccluded teeth,others are unerupted with a large follicle 3.decidous and permanent teeth involved 4.unilateral and asymmetric 5.tendency for ankylosis 6.orthodontic treatment leads to ankylosis Orthodontic extrusive forces will have no effect on the infraoccluded tooth. TREATMENT OPTIONS 1.Proffitt and Vig suggest that orthodontic treatment in these patients is not advisable 2.Even if attempted,procedure is surgical luxation with continous orthodontic force.
  45. 45. Ankylosed teeth A situation in which the cementum is directly fused to the bone, presenting as a difficult problem for the patient and for the orthodontist. CAUSE Several factors, such as endocrine or metabolic diseases, as well as local conditions, such as periapical infections, trauma, and previous surgical procedures are possible causes. CLINICAL FEATURES The diagnosis is based on the lack of tooth movement and by percussion when a dull sound is obtained. When the ankylosis involves the proximal root areas, it can be seen in periapical radiographs.
  46. 46. TREATMENT OPTIONS The best treatment according to Proffit is the surgical luxation of the tooth followed by orthodontic traction. In the case of a severely ankylosed and malpositioned tooth, one should the following are treatment options: 1. Exodontia followed by reimplantation. External resorption usually occurs . 2. Exodontia followed by placement of an osseointegrated implant and hydroxiapatite 3. Exodontia followed by prosthetic rehabilitation, and
  47. 47. 4. The single-tooth dento-osseous osteotomy is a feasible procedure for upper ankylosed teeth because of the favorable vascularity of the maxilla.Ideally, the best time to perform this type of osteotomy would be after the facial growth has been completed
  48. 48. Dilacerated tooth CAUSE Often trauma is inflicted on the deciduous maxillary incisor in superior and posterior directions will cause the crown of the unerupted permanent tooth to rotate upwards in its crypt.The formed part of the root will rotate with the crown. But any further root development in the post trauma period will continue in the same direction as before, leading to a typical dilacerated central incisor. Other causes are the loss of deciduous incisor may lead to scaring along the eruption path deflecting the erupting tooth. The developmental origin has also been suggested as an alternative.
  49. 49. APICAL ROOT DILACERATION If the dilacerations is situated apical to the coronal third of the root, orthodontic alignment will result in excellent prognosis. TREATMENT OPTIONS: In most cases, the palatal surface of the crown is bonded and extrusive force is applied. As the crown of the tooth rotates downwards, the root apex rotates towards the labial plate of the bone. The labially directed portion of the root is sectioned and the root canal is obliterated using a combined conventional (coronal) and retrograde endodontic approach.
  50. 50. CROWN DILACERATION TREATMENT OPTIONS The attachment is placed on the labial surface and orthodontic force will bring the root portion of the tooth from its more palatally displaced location close to its normal position. The restorative treatment is indicated later. PROGNOSIS Long term prognosis of dilacerated tooth is poor and their extraction and replacement is probably a part of the long term treatment strategy. Orthodontic alignment of the dilacerated tooth will bring with it much alveolar bone. Retention of a very short rooted endodontically treated tooth will preserve the normal shape of the alveolar ridge.
  51. 51. Traumatically intruded tooth Predominantly involves the maxillary anterior teeth. Sequelae often includes pulp necrosis, pulp obliteration, root resorption, ankylosis, and loss of marginal bone. TREATMENT OPTIONS Most reported cases of permanent tooth reeruption have been those with incomplete root formation. Traumatically intruded permanent teeth with closed apices do not re-erupt as often. ( BRUSZT 1958, ANDREASEN 1970 ) Light extrusive forces are applied after the time that the periodontal fibres have begun to reunite and in the earlier stages of organization of the blood clot,but before the laying down of bone i.e 10 –28 days post trauma
  52. 52. A button is placed on the labial of the intruded tooth and the labial bow of a removable plate is divided at the midline and activated vertically downwards against the button. Once the tooth erupts root canal therapy is initiated and permanent restoration is placed.
  53. 53. Congenitally Missing Teeth Hypodontia, is the most commonly encountered anomaly in humans. After taking into account third molars, the most commonly missing teeth are the second premolars and maxillary lateral incisors. It is important to note that different races have different predilections for congenitally missing teeth. For instance, the most commonly missing teeth in the Asian dentition are the mandibular incisors. Also seen in ectodermal dysplastic patients CAUSE The causes of hypodontia can at best be termed multifactorial. Missense in MSX1 gene appears to be responsible to the agenesis of second premolars and third molars. PAX9, a gene is associated with tooth agenesis. A frame shift mutation is associated with autosomal dominant oligodontia.
  54. 54. TREATMENT OPTIONS 1. If there is crowding anticipated in the arch, then the missing tooth may be used like an extraction space. 2 Otherwise, the space can be restored by fixed and removable partial dentures, resin-bonded partial denture, or an osseointegrated implant anchoring a fixed restoration. The goal of the orthodontic treatment, is to close or redistribute the space so as to optimize the occlusal and aesthetic effectiveness of the prosthetic restorations.
  55. 55. 3.Autotransplantation According to Slagsvold and Bjercke, premolar transplantations performed at any stage before complete root formation The use of autotransplantations can be a valuable alternative to implantation, a method complicated in children by the involution of alveolar bone after the early loss of teeth.
  56. 56. MISSING MAXILLARY LATERAL INCISORS TREATMENT OPTIONS Treatment plans are either space closure or space reopening. Space reopening involves creating space for the missing teeth with implants or resin bonded bridges. Space closure is achieved by the mesial movement of the cuspids and the bicuspids replacing the lateral incisor and the canine respectively.
  57. 57. SPACE CONSOLIDATION •Esthetic recontouring of cuspid to a more ideal lateral incisor shape and size, by grinding and composite resin or porcelain laminate veneers. •Intentional whitening by vital bleaching of a yellowish cuspid •Careful correction of the crown torque of a mesially relocated cuspid, along with the provision of optimal torque for the mesially moved maxillary first and second premolar.. •Individualized extrusion and intrusion during the mesial movement of the cuspids and first bicuspids respectively to obtain an optimum level for the marginal gingival contours of the anterior teeth.
  58. 58. •Nordquist has shown that an adequate group function occlusion can be obtained with the first bicuspids substituting for the cuspids. Increasing the width and the length of the mesially moved first bicuspids with composite resin and porcelain laminate veneers so as to achieve even cuspid protected guidance. •Localized clinical crown lengthening procedures
  59. 59. Advantages of space closures are (i) The treatment result is permanent. (ii) Normal gingival topography around the mesially relocated cuspids is created, which is crucial especially in patients with high smile lines. (iii) Cost effective since no implants or prosthetic replacements are needed. Disadvantages of space reopening are: (i) Commits the patient to a life long artificial restoration in the most visible area of the mouth where the tooth shade and transparency along with gingival colour, contour and marginal levels are critical. (ii) Unaesthetic “blueing” of the marginal gingivae or even disclosure of the implant margins is seen after several years. (iii) The implant and the final restoration cannot usually be placed until all the skeletal growth is completed and tooth eruption is ceased.
  60. 60. MISSING MANDIBULAR INCISORS Four main theories Heredity or familial distribution has been suggested as the primary cause. Second, anomalies in the development of the mandibular symphysis may affect the dental tissues forming the tooth buds of the lower incisors Third, a reduction in the dentition is regarded by some researchers as nature's attempt to fit the shortened dental arches. Finally, localized inflammation or infections in the jaw may have destroyed the tooth buds, or disturbance of the endocrine system may have caused an ectodermal dysplasia. Congenitally missing mandibular incisors are occasionally noted in orthodontic treatment.
  61. 61. TREATMENT OPTIONS 1.the creation of space for a fixed prosthesis to replace the missing incisors, 2.the removal of maxillary premolars or a lateral incisor to balance the deficient mandibular tooth material, 3.consolidation of the mandibular incisor spaces to facilitate correction of the malocclusion. Evidently the unusual occlusions of six maxillary anteriors occluding with four or five mandibular incisors did not play a part in causing temporomandibular joint problems.
  62. 62. Supernumerary Teeth Supernumerary teeth can be defined as those teeth in excess of the normal dental formula. Males are affected approximately twice as frequently as females in the permanent dentition. Descending order of occurrence; the mesiodenslocated between the central incisor teeth, the maxillary third molar, the mandibular third molar, mandibular premolar, mandibular incisor, and maxillary premolar regions. Occur in conjunction with cleft palate and cleidocranial dysostosis, but more commonly seen among otherwise normal, healthy persons
  63. 63. CAUSE Supernumerary teeth may occur as isolated dental findings or as part of a syndrome; cleidocranial dysostosis,Gardener`s syndrome.Assumed to be polygenic in most instances. supernumerary tooth is suggested to be a result of dichotomy of a tooth bud. CLASSIFICATION When classified by location, they are termed as mesiodens, between the maxillary central incisors; paramolars, usually between the second and third molars; retromolar, distal to the third molars; and parapremolars, in the premolar region. The shapes are divided into supplemental and rudimentary. Supplemental teeth have a normal size and shape and are difficult to distinguish from a "normal tooth." Rudimentary teeth are further divided into conical, tubercular, and molariform.
  64. 64. SEQUELAE OF SUPERNUMERARY TOOTH The position of the supernumerary teeth can cause crowding, malalignment or disruption of proper eruption of the normal dentition or may lead to the development of dentigerous or primordial cysts, root resorption of adjacent teeth or inversion of the supernumerary into the nasal cavity. Because of these disruptions, it is usually necessary to extract the supernumerary tooth or teeth to correctly align the dental arches, or to allow for proper eruption. In a small number of instances, the shape and position of the supernumerary tooth as well as an excess of space in the dental arch will allow the supernumerary tooth to be maintained as a part of the functioning dental unit
  65. 65. TREATMENT OPTIONS Early surgical excision is advised only if they are actually interfering with the development or eruption of a permanent tooth, particularly an incisor. Aside from this, there is much to commend leaving them untreated until the full permanent dentition has developed and the ideal time for orthodontic treatment is at hand. This achieves several purposes: 1. A reasonable observation period is allowed to determine if other supernumerary teeth will calcify, so that surgery can be limited to one session. 2. Surgical removal of supernumerary teeth may inflict damage on unerupted teeth.
  66. 66. CONCLUSION The orthodontist needs to carefully evaluate developing dentitions for eruptive anomalies during screening procedures as these problems of eruption can be identified early and preventive as well as interceptive or active orthodontics can be instituted as early as possible.
  67. 67. Thank you Leader in continuing dental education