Impacted teeth

Definition, Etiology, Classification, Indications and Contraindications for removal, Jaw lesions associated with impacted teeth, Management

1. IMPACTED TEETH BY, SREELEKSHMI J INTERN KVG DENTAL COLLEGE

2. CONTENTS Definition Frequency of impacted teeth Theories of mandibular impaction Etiology of Impaction Indications for removal of impacted teeth Contraindications for removal of impacted teeth Classification Radiological Examination Management of Impacted canine Surgical removal of impacted teeth Complications References

3. DEFINITION Impacted tooth is defined as a tooth which is completely or partially unerupted , is positioned against another tooth, bone or soft tissue so that its further eruption is unlikely and described according to its anatomic position.

4. FREQUENCY OF IMPACTED TEETH Frequency of impacted teeth occurs in the following order: Mandibular third molars Maxillary third molars Maxillary cuspids Mandibular bicuspids Mandibular cuspids Maxillary bicuspids Maxillary central incisors Maxillary lateral incisors

5. THEORIES OF MANDIBULAR IMPACTION One of the most popular theories is insufficient development of the retromolar space. Few other theories are described below: Orthodontic theory(small jaw-decreased space): Jaws develop in downward and forward direction, while as the teeth move in a forward direction; the presence of dense bone decreases the movement of teeth in a forward direction. Growth of the jaw and movement of teeth occurs in forward direction, anything that interferes with such moment will cause an impaction (small jaw-decreased space). A dense bone decreases the movement of the teeth in forward direction.

6. Causes for the increased density of bone are Acute infection Local inflammation of PDL Malocclusion Trauma Early loss of primary teeth and arrested growth of the jaw, leading to insufficient space available for normal eruption. This condition is without doubt the cause of impaction.

7. Nodine’s Phylogenic theory ( Nodine 1943) [More- functional masticatory force – better the development of the jaw]: Nature tries to eliminate the disused organs. This causes elimination of the unused teeth which causes congenital absence of third molars. It is also known that in about 10% of the Caucasian race, third molars are lacking, as the mandible and maxilla decreased in size leaving insufficient room for third molars i.e., used makes the organ develop better, disuse causes slow regression of the organ. Due to changing nutritional habits, our civilisation have practically eliminated needs for large powerful jaws, thus, over centuries the mandible and maxilla decreased in size leaving insufficient room for third molars.

8. Mendelian theory: Heredity is the most common cause. An individual may inherit small jaws from one parent and a complement of large teeth from the other, i.e., hereditary transmission of small jaws and large teeth from parents to children. This may be an important etiological factor in the occurrence of impaction, i.e., small mandible with impaction of second and third molars. Pathological theory: Osteosclerosis in the third molar area, caused by the early disease of adjacent molars, cause chronic infections affecting an individual and may bring the condensation of osseous tissue further preventing the growth and development of the jaws.

9. Endocrinal theory: Increase or decrease in the growth hormone secretion may affect the size of the jaws. An imbalance of endocrine activity leads to the lack of growth of the jaws, this lack provides a cause for impaction. Nature and nurture theory: Described by A. J. MacGregor explains that impaction can occur due to a mismatch in size and shape of teeth and jaws. This can be due to Primate evolution owing to the increase in brain size with the sacrifice of the jaw size without reduction in the teeth size. Change of diet of the modern civilisation due to under used teeth.

10. Loss of use of weapons by the civilisation as cooking decreases tough and abrasive food. With all these changes it is important to note that the dentition has not reduced in size as it should have in attrition. Attrition causes increased muscle activity that stimulates jaw growth but instead there has been an increase in impaction. This is due to the absence of constant chewing due to high-calorie cooked food.

11. ETIOLOGY OF IMPACTION Berger lists the following local and systemic causes of impaction. LOCAL CAUSES: Irregularity in the position and pressure of the adjacent tooth. Density of the overlying or surrounding bone. Localised chronic inflammation with resultant increase in density of the overlying mucous membrane. Lack of space due to underdeveloped jaws. Arch length and tooth size discrepancy.

12. Obstructions: It can be a soft or hard tissue obstruction caused by retained deciduous teeth, thick fibrous alveolar mucosa or chronically inflamed mucosa, dense bone with inflammatory changes due to odontome , cyst or odontogenic tumour that prevents eruption at the chronological age. Dilaceration : Abnormal path of eruption of the tooth due to traumatic forces during the eruption period. Over retained deciduous teeth. Ectopic position of tooth bud.

13. A calcifying odontogenic cyst associated with the right maxillary impacted third molar with dense opaque foci throughout the cystic cavity.

14. A panoramic view shows a unicystic ameloblastoma presenting as a unilocular radiolucent lesion associated with the right mandibular impacted third molar.

15. A multilocular extensive ameloblastoma is found on the right aspect and ramus of the mandible in relation to an impacted molar tooth.

16. This panoramic view shows an adenomatoid odontogenic tumor occurring as a unilocular radiolucent lesion surrounding the crown of the right maxillary impacted permanent canine.

17. An extensive keratocystic odontogenic tumor as a multilocular radiolucent lesion in the left mandibular ramus in close approximation to the impacted third molar.

18. A calcifying epithelial odontogenic tumor is seen in the left posterior mandible as a mixed lesion with dense opaque foci associated with an impacted tooth.

19. This panoramic view shows a large complex odontoma associated with the impacted left mandibular third molar.

20. SYSTEMIC CAUSES: General causes Prenatal causes: Heredity Postnatal causes: All those conditions that may interfere with the development of the child, such as: Rickets Anaemia Congenital syphilis Tuberculosis Endocrine dysfunctions Malnutrition

21. Rare conditions: Cleidocranial dysostosis Oxycephaly Progeria Osteopetrosis Cleft palate

22. INDICATIONS FOR REMOVAL Infections: Removal of any symptomatic impacted tooth should be considered with food impaction causing halitosis, especially where there have been one or more episodes of infection such as pericoronitis(75-80% of patients with impacted third molar develop pericoronitis), cellulitis, abscess formation; or untreatable pulpal/periapical pathology. Unrestorable caries: Removal should be considered when there is caries in the impacted tooth or when there is caries in the adjacent second molar tooth which cannot be satisfactorily treated without removal of the third molar.

23. Third molar causing dental caries Pericoronitis

24. Periodontal diseases: When there is periodontal disease between the third and second molar, early removal of the impacted third molar will result in repair of the injured periodontium and is therefore beneficial. Untreated impacted teeth are particularly prone to cause bone loss distal to the adjacent teeth due to pressure effect. Dentigerous cyst formation: Other related pathologies which expand the bone and results in pathological fracture. External resorption of the second molar: Caused by the pressure of the third molar on 2 nd molar.

25. Dentigerous cyst involving 3 rd molar External root resorption of 2 nd molar associated with 3 rd molar impaction

26. Buccoverted impacted molars: May cause cheek bite, frictional keratosis or traumatic fibroma mandating extraction. Third molar removal may occasionally be indicated for orthodontic reasons . Removal of the third molar may be indicated prior to orthognathic surgery , e.g. when a sagittal split osteotomy is planned, removal of the third molar diminishes the risk of surgical complications with regard to that of osteotomy. Prophylactic removal in presence of specific medical and surgical conditions. Fracture of the mandible in the third molar region or when a tooth is involved in tumour resection.

27. Atypical pain from an unerupted third molar is the most unusual situation and it is essential to avoid any confusion with temporomandibular joint (TMJ) or muscle dysfunction before considering removal. Impacted teeth in edentulous ridge that causes ulcerations in the mucosa under a denture . Third molar removal may be considered for autogenous transplantation to a first molar socket .

28. CONTRAINDICATIONS FOR REMOVAL Impacted teeth which are likely to erupt successfully and have a functional role in the dentition should not be removed. Partially impacted teeth which can be used as an abutment in the construction of fixed partial denture. Medical history contraindicates surgical procedure. Deeply impacted third molars in patients with no history of any bony pathology to avoid damage to the vital structures. Third molars should not be removed in patients where the risk of surgical complications is judged to be unacceptably high or where fracture of an atrophic mandible may occur.

29. CLASSIFICATION Impacted mandibular third molars are classified : Based on the nature of the overlying tissue Winter’s classification Pell and Gregory’s classification

30. Based on the nature of overlying tissue Soft tissue impaction – The presence of dense fibrous tissues overlying the teeth sometimes prevents its normal eruption. This is frequently seen in cases of permanent central incisors, in which early loss of primary teeth with subsequent masticatory trauma to the ridge results in fibrosis. Hard tissue impaction – When the teeth fail to erupt due to obstruction caused by the overlying bone, it is known as hard tissue impaction. Here the impacted tooth is completely encased in bone so that, when the soft tissue flap is reflected, the tooth is not visible. Extensive amount of bone must be removed and the tooth may require sectioning before removal.

31. Winter’s Classification It is based on inclination of the impacted third molar tooth to the long axis of the second molar. Mesioangular : Long axis of 3 rd molar bisects the long axis 2 nd molar at or above occlusal plane. This is the most common type of impaction. Distoangular : Long axis of 3 rd molar away from long axis of 2 nd molar at the level of occlusal plane. This type is rare.

32. Horizontal: Long axis of 3 rd molar bisect long axis of 2 nd molar at right angle. Vertical : The long axis of the impacted tooth runs parallel to the long axis of the 2 nd molar . Buccal or Lingual: In combination to the above described impaction, the tooth can also be buccally or lingually impacted. Transverse: Tooth completely impacted in the buccolingual direction.

33. Pell and Gregory’s Classification Based on their relationship with the anterior border of the mandible Class I : The anteroposterior diameter of the tooth is equal to the space between the anterior border of ramus of the mandible and distal surface of the second molar tooth. Class II : A small amount of bone covers the distal surface of the tooth and the space is inadequate for eruption of the tooth, i.e., mesiodistal diameter of the tooth is greater than the space available. Class III : Tooth is located completely within the ramus of the mandible – least accessible.

34. Based upon the amount of bone covering the impacted tooth and relation to occlusal plane Position A : Occlusal plane of the impacted tooth is nearly in the same level as the occlusal level of the adjacent second molar tooth. Position B : Occlusal plane of the impacted tooth is in the midway between the cervical line and the occlusal plane of the adjacent second molar tooth. Position C : Occlusal plane of the impacted tooth below the level of cervical line of the second molar tooth.

35. Maxillary third molar classification Angulation and depth classification is same as mandibular third molars . Classification of the maxillary third molar in relation to the floor of maxillary sinus . Sinus approximation (SA)—no bone or a thin bony partition present between impacted maxillary third molar and the floor of the maxillary sinus . No sinus approximation (NSA)—2 mm or more bone is present between the sinus floor and the impacted maxillary third molar .

36. No Sinus Approximation Sinus Approximation

37. C lassification of I mpacted Maxillary canines Labial or palatal placement of impacted maxillary canine • Intermediate position: – Crown between the lateral incisors and premolar. – Crown above the root tip with labial/palatal orientation of the lateral incisor or premolar. • Aberrant position: Impacted maxillary canines lie in the maxillary sinus or nasal cavity . Class I: Palatally placed maxillary canine Horizontal Vertical Semivertical

38. Class II: Labially or buccally placed maxillary canine Horizontal Vertical Semivertical Class III: Involving both buccal and palatal bone, e.g . crown is placed on the palatal aspect and the root is toward the buccal alveolar process Class IV: Impacted in the alveolar process between the incisors and first premolar. Class V: Impacted in the edentulous maxilla.

39. RADIOLOGICAL EXAMINATION INTRAORAL X-RAY The position and depth of the tooth can be assessed by taking intraoral X-ray or even lateral extraoral X-ray and tracing can be done, which was originally advocated by George Winter . Three imaginary lines are drawn which are known as Winter’s lines . White line corresponds to the occlusal plane. The line is drawn touching the occlusal surfaces of first and second molar and is extended posteriorly over the third molar region. It indicates the difference in occlusal level of second and third molars.

40. Amber line represents the bone level. The line is drawn from the crest of the interdental septum between the molars and extended posteriorly distal to third molar or to the ascending ramus. This line denotes the alveolar bone covering the impacted tooth and the portion of tooth not covered by the bone . Red line is drawn perpendicular from the amber line to an imaginary point of application of the elevator. It indicates the amount of bone that will have to be removed before elevation, i.e . the depth of the tooth in bone and the difficulty encountered in removing the tooth. If the length of the red line is more than 5 mm then the extraction is difficult. Every additional millimeter renders the removal of the impacted tooth three times more difficult (more than 9 mm—below the level of the apices of the second molar).

41. EXTRAORAL X-RAYS For mandibular teeth • OPG • Lateral oblique view mandible For maxillary teeth • OPG • PA view Water’s position

42. MANAGEMENT OF IMPACTED CANINE Interceptive treatment Treatment of labial impaction Treatment of palatal impaction Methods of applying traction Retention consideration

43. INTERCEPTIVE TREATMENT: When the clinician detects early signs of ectopic eruption of canines, an attempt should be made to prevent their impaction and its potential sequelae. Selective extraction of the deciduous canines as early as 8 or 9 years of age. Normalise the eruption of ectopically erupting permanent canine.

44. LABIAL IMPACTION OF IMPACTED CANINE: Due to ectopic migration of canine crown over the root of lateral incisor or insufficient space in the arch caused by midline shift of dental origin. Arch length – tooth material discrepancy is the most common cause. Extraction of deciduous canine at early age of 8 or 9 years will enhance eruption and self correction of labial impaction.

45. SURGICAL EXPOSURE: Indicated when tooth does not erupt spontaneously after creating space in the arch. Attempted 6 months after the root formation. Flap designs should preserve the band of attached gingiva and should guide tooth to erupt through its natural path of eruption.

46. PALATAL IMPACTION OF MAXILLARY CANINE: CLOSED ERUPTION Crown is surgically exposed, an attachment is bonded during the exposure, flap is sutured back, leaving a twisted ligature wire passing through the mucosa to apply orthodontic traction. OPEN WINDOW ERUPTION TECHNIQUE A flap is raised, bone covering crown is removed, small window or fenestration is made, orthodontic attachment is bonded and flap is sutured into place.

47. ATTACHMENTS : Lasso wires Threaded pins Orthodontic bands Magnets

48. Standard orthodontic bracket A simple eyelet Elastic ties and modules

49. RETENTION CONSIDERATIONS: Relapse of rotations and spacing may occur after completion of the orthodontic treatment of an impacted canine. Supracrestal Fibrotomy Fixed retainers Removal of half moon shaped wedge tissue (To prevent lingual drift of palatally impacted canine)

50. SURGICAL REMOVAL OF IMPACTED TEETH Local anaesthesia Incision—flap design Reflection of mucoperiosteal flap Bone removal Sectioning (division) of tooth Elevation Extraction Debridement and smoothening of bone Control of bleeding Closure—suturing Medications—antibiotics, analgesics, etc. Follow up.

51. Local Anaesthesia: For mandibular molars and canines— pterygomandibular nerve block For maxillary molars—posterior superior alveolar nerve block and palatine nerve block or infiltration For maxillary canines—infraorbital nerve block + palatal infiltration of incisive canal and bilateral palatine nerve blocks. Good infiltration is a must to provide hemostasis and to define the tissue planes. Saline adrenaline in concentration of 1:400000 Plain saline (in case of hypertensive patients) LA solution with adrenaline.

52. Incision (Flap Design): For Mandibular Molars Vertical mucoperiosteal flap design An envelope flap design

53. For M axillary Molars: Mucoperiosteal flap design for the removal of impacted maxillary third molar. Dotted line indicates possible extension of the incision for additional access

54. Bone removal: -Two Ways of Bone Removal

55. Tooth sectioning, elevation and extraction Sectioning method during removal of impacted lower third molar: ( 1) Sectioning of the horizontally placed lower third molar, (2) Sectioning of the mesioangularly placed lower third molar, ( 3) Sectioning of the vertically placed lower third molar, ( 4) Sectioning of the distoangularly placed lower third molar

56. E levation Coupland elevator— placed at the base of the crown. Winter Cryer’s— may be used in wedging action/buccal elevation. Buccal elevation may be done in molar and canines by drilling a purchase point in the roots just below CEJ . Wedging action is useful, when molar crown is split vertically down to bifurcation of roots. Important precautions: Support the inferior border and lingual cortex of the bone in the mandibular impaction. Support to the palatal bone in the maxillary third molar or canine impactions during elevation should be given. Support the neighbouring tooth to prevent luxation of the same.

57. Debridement and smoothening of Bone Margins • Irrigation of the socket • Curetting to remove any remaining dental follicle and epithelium • Look for pieces of coronal portion (especially in carious teeth/sectioned teeth), check for remnants of bone/granulation tissue, bleeding points • Check for caries (root/crown)/erosion/damage to the adjacent teeth • Round off the margins of the socket with large vulcanite round bur or bone file •Irrigate the socket again • Control bleeding before suturing.

58. C losure 3-0 black silk is used. Interrupted sutures given and maintained for 7 days. In case of molars, suture distal to second molar should be placed first and should be water tight to prevent pocket formation. In case of palatally impacted canines, incisive papilla should be sutured carefully to reduce postoperative bleeding .

59. COMPLICATIONS I ntraoperative Complications: During Incision For molars, facial vessel or buccal vessel may be cut. For lower canines–mental vessels and for upper canines— incisive canal or greater palatine vessels may be damaged . During Bone Removal Damage to the second molar, damage to the roots of overlying teeth, slipping of the bur into the soft tissues, fracture of the mandible when using chisel and mallet .

60. During Elevation • Luxation of neighbouring/overlying tooth • Fracture of the adjoining bone • Fracture of the tuberosity • Slipping of the tooth into pterygomandibular /temporal spaces , sublingual pouch and/maxillary sinus. • Damage to nasal wall/overlying teeth/lingual, inferior alveolar or mental nerve . During Debridement • Damage to inferior alveolar nerve/lingual nerve. • Damage to maxillary sinus.

61. Postoperative complications Pain , swelling, trismus, hypoesthesia, sensitivity, loss of vitality of neighbouring teeth . • Pocket formation. • Sinus tract formation, oroantral fistula, oronasal fistula .

62. REFERENCES Textbook of Oral and Maxillofacial Surgery – Third Edition – Neelima Anil Malik Textbook of Oral and Maxillofacial Surgery – Third Edition – S M Balaji Shafer’s Textbook of Oral Pathology Jaw lesions associated with impacted tooth: A radiographic diagnostic guide retrieved from https ://www.ncbi.nlm.nih.gov/pmc/articles/PMC5035719 /