Impaction

Impaction

1. IMPACTION

2. WHAT IS IMPACTION? A tooth which is completely or partially unerupted and malpositioned against another tooth, bone or soft tissue beyond its chronological age.

3. Frequency of impacted teeth occurs in the following order : 1. Mandibular third molars 2. Maxillary third molars 3. Maxillary cuspids 4. Mandibular bicuspids 5. Mandibular cuspids 6. Maxillary bicuspids 7. Maxillary central incisors 8. Maxillary lateral incisors

4. Theories of impaction Orthodontic theory (small jaw-decreased space): 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: acute infection Local inflammation of PDL Malocclusion, Trauma Early loss of primary teeth and arrested growth of the jaw

5. Nodine’s Phylogenic theory : Nature tries to eliminate the disused organs. This causes elimination of the unused teeth which causes congenital absence of third molars. 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.

6. 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. Endocrinal theory: Increase or decrease in the growth hormone secretion may affect the size of the jaws. Nature and nurture theory: A. J. MacGregor explains that impaction can occur due to a mismatch in size and shape of teeth and jaws.

7. ETIOLOGY Local causes Irregularity in the position and pressure of the adjacent tooth. • Density of the overlying or surrounding bone. • Localised chronic inflammation • Lack of space due to underdeveloped jaws. • Obstructions (soft or hard tissue ) • Dilaceration • Over retained deciduous teeth. • Ectopic position of tooth bud.

8. Systemic causes A. Prenatal causes: Heredity B. Postnatal causes: 1. Rickets 2. Anaemia 3. Congenital syphilis 4. Tuberculosis 5. Endocrine dysfunctions 6. Malnutrition C. Rare conditions: 1. Cleidocranial dysostosis 2. Oxycephaly 3. Progeria 4. Osteopetrosis 5. Cleft palate

9. IMPACTED THIRD MOLAR

10. PERICORONITIS Pericoronitis refers to inflammation of soft tissues around and covering the partially or completely erupted third molar.

11. Bacterial growth beneath the soft tissue flap Trauma caused to the soft tissue flap overlying the mandibular third molar by the cusps of the opposing maxillary third molar. CAUSES SYMPTOMS Soft tissues show the four cardinal signs of inflammation namely pain, redness, swelling and warmth . Chills, fever, malaise and halitosis are present. Regional lymph nodes may be enlarged, tender and indurated

12. TREATMENT The pericoronitis can be treated in the following manner: • Conservative method • Surgical removal of the overlying flap • Surgical removal of the tooth

13. CONSERVATIVE METHOD Irrigation with warm saline should be done beneath the flap. Alternatively, 1cc iodine solution can also be used to irrigate beneath the flap.The usually used irrigating solution consists of : Phenol 5% • Tincture of aconite • Tincture of iodine • Glycerine

14. SURGICAL METHOD OPERCULECTOMY Operculum is the dense fibrous flap which covers about 50% of the occlusal surface of a completely or partially erupted mandibular third molar. The removal of this flap is known as operculectomy . This flap can be best removed with the help of electrosurgical scalpel or radiosurgical loop.

15. INDICATIONS FOR REMOVAL Infections Unrestorable caries Periodontal disease Dentigerous cyst formation External resorption of 2 nd molar Buccoverted impacted molars Prior to orthognathic surgery Fracture of mandible For orthodontic treatment

16. CONTRAINDICATIONS FOR REMOVAL Impacted teeth which are likely to erupt successfully Partially impacted teeth which can be used as an abutment Deeply impacted third molars in patients with no history of any bony pathology to avoid damage to the vital structures. Where the risk of surgical complications is judged to be unacceptably high.

17. CLASSIFICATION Based on the nature of the overlying tissue Winter’s classification Pell and Gregory’s classification

18. BASED ON THE NATURE OF THE OVERLYING TISSUE i . Soft tissue impaction ii. Hard tissue impaction

19. B. WINTER’S CLASSIFICATION Mesioangular : Long axis of 3rd molar bisects the long axis 2nd molar at or above occlusal plane Mesioangular 38—(A) long axis of 38 bisects the long axis 37 above the occlusal plane. (B) Interradicular bone width between 37 and 38 is more than interradicular bone width between 36 and 37.

20. Distoangular : Long axis of 3rd molar away from long axis of 2nd molar at the level of occlusal plane Distoangular —(A) long axis of 48 is away from long axis of 47 at the level of occlusal plane. (B) The interradicular bone between 47 and 48 is almost obliterated and less than that between 46 and 47.

21. III. Horizontal: Long axis of 3rd molar bisect long axis of 2nd molar at right angle. Horizontal—long axis of 38 bisects long axis of 37 at right angle.

22. Vertical : The long axis of the impacted tooth runs parallel to the long axis of the second molar (A) Vertical—the long axis of the impacted 48 runs parallel to the long axis of the 47. (B) Vertical— interradicular bone width between 47 and 48 equal to interradicular bone width between 46 and 47.

23. C . 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.

24. II. 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 occlusal level of 47. 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 tooth. This can be applied for the maxillary teeth also.

25. III. Based on long axis of the impacted tooth : It is similar to the one as proposed in the Winter’s classification

26. CLINICAL EVALUATION

27. LOCAL EXAMINATION Occlusal relationship Presence of local infection Periodontal status Resorption of the second molars External oblique ridge Internal oblique ridge Upper third molar Soft tissue assessment Regional lymph nodes

28. RADIOLOGICAL ASSESSMENT Types of radiographs used • Intraoral periapical (IOPA) radiograph • Bitewing radiograph • Occlusal radiograph • Lateral oblique radiograph • Orthopantomograph (OPG) • CBCT (in indicated cases)

29. INTERPRETATION OF THE RADIOGRAPH WAR lines White line White line is drawn along the occlusal surfaces of the erupted mandibular molars and extended over the third molar region posteriorly . Indicates ▪ The depth of the tooth within the mandible. ▪ Relationship of occlusal surface of impacted tooth with the erupted molars.

30. Amber line Amber line is drawn from the surface of the bone on the distal aspect of the third molar to the crest of the interdental septum between the first and second mandibular molars. This line represents the margin of the alveolar bone covering the third molar.

31. Red line It is the perpendicular line drawn from the amber line to the imaginary point of application for the elevator (all types- mesial , distoangular -distal) The length of the red line indicates depth of the impacted tooth. With each increase in length of the red line by 1 mm, the impacted tooth becomes three times more difficult to remove.

32. ASSESSMENT OF DIFFICULTY OF REMOVAL

33. SURGICAL REMOVAL OF IMPACTED THIRD MOLAR

34. Step 4 : Incisions placed

35. Step 5 : Buccal Mucoperiosteal flap raised Step 6 : Lingual Mucoperiosteal flap raised and complete exposure of the tooth done.

36. Step 7 : Guttering of the mesial and distal bone. Step 8 : Odontectomy performed.

37. Step 10: Removal of mesial segment Step 9 : Removal of distal segment

38. Step 11 : Extraoral reorientation of the extraoral fragments. Step 12 : Wound debridement and primary closure.

39. TYPES OF FLAPS (A) Envelope flap, (B) L-shaped flap, (C) Bayonet flap with Wards incision, (D) Trapezoidal flap.

40. OTHER TECHNIQUES A. LATERAL TREPHINATION TECHNIQUE The external oblique ridge is palpated and an S-shaped incision is made. Incision line starts from the retromolar fossa and extends across the external oblique ridge curving down along the reflection of the mucous membrane above the vestibule and ends anterior to the first permanent molar.

41. Using a round bur, the buccal cortical plate over the third molar crypt is trephined and is fractured to expose the third molar crypt using a chisel Using an elevator, the impacted tooth is delivered out of the crypt.

42. B. LINGUAL SPLIT TECHNIQUE (Kelsey fry technique) Takes advantage of the thinness of the lingual cortical plate, avoids and preserves plate and hence preserves the buccal plate and external oblique ridge.

43. IMPACTED CUSPIDS

44. RADIOGRPAHIC LOCALISATION OF IMPACTED MAXILLARY CUSPIDS Principle of Parallax by Charles A. Clark: By changing the angulation of the X-ray beam, an apparent displacement of the object to be localised was seen. If the object to be localised is farther ( palatally or lingually placed object) from the X-ray tube then the image of the object moves in the same direction as the tube, whereas the image of the object closer to the X-ray tube ( buccally placed object) moves in the opposite direction.

45. CLASSIFICATION A. Classification based on position in the dental arch Class I: Impacted cuspids in palate 1. Horizontal 2. Vertical 3. Semivertical Class II: Impacted cuspids on buccal surface 1. Horizontal 2. Vertical 3. Semivertical Class III: Impacted cuspids located both in the palatal process and labial maxillary bone Class IV: Impacted cuspids located in the alveolar process usually vertical between the incisor and bicuspid. Class V: Impacted cuspid located in an edentulous maxilla.

46. B. Field and Ackerman classification (1935) Maxillary canines : a. Labial position: 1. Crown in intimate relationship with incisors 2. Crown well above the apices of incisors b. Palatal position: 1. Crown near the surface, in close relationship to roots of incisors 2. Crown deeply embedded in close relationship to apices of incisors c. Intermediate position 1. Crown between lateral incisors and 1st premolar roots 2. Crown above these teeth with crown labially placed and root palatally placed or vice versa d. Unusual positions 1. In nasal or antral wall 2. In infraorbital region

47. Mandibular canines a. Labial position: 1. Vertical 2. Oblique 3. Horizontal b. Unusual positions 1. At inferior border 2. In mental protuberance 3. Migrated to the opposite side along with the original nerve supply

48. TREATMENT i . No treatment ii. Surgical removal of unerupted canine iii. Surgical exposure of the crown with or without orthodontic treatment iv. Surgical repositioning v. Surgical transplantation

49. SURGICAL REMOVAL Removal of impacted cuspids in class I position : No. 12 BP blade is used to incise the tissues around the neck of the teeth and the flap is raised as a mucoperiosteal flap from the hard palate Bone is removed circumferentially 3 mm around the crown of the impacted tooth and the tooth is lifted from itscrypt in the palate

50. All the debris, spicules are removed and bony margins trimmed. The flap is compressed onto the palatal bone with a gauze palatal packing placed for 4 h.

51. Removal of impacted cuspid in class II position Labially placed impacted canine—can be exposed by using 1. Trapezoidal flap—two vertical limbs 2. Semilunar flap—no vertical limb 3. Triangular flap—only one vertical limb Mucoperiosteal flap is raised. bone is removed by using a chisel or bur to expose the crown. elevator is inserted into the space between the bone and the tooth, to luxate the tooth. Triangular flap Trapezoidal flap Semilunar flap

52. Removal of impacted cuspid in class III position A semicircular flap is raised to expose the root apex. bone removal is done exposing the root. Root is sectioned and delivered labially . Palatal flap is outlined and mucoperiosteal flap reflected and the bone overlying the crown is removed. A blunt instrument is placed in contact with the root end of the crown through the buccal crypt and tapped with a mallet, driving the crown out of its crypt palatally . The flap is replaced and the wound closed primarily. (A). Crown in the palatal bone and root on buccal side

53. (B) Maxillary cuspid lying in the line of arch—along alveolar crest When an impacted maxillary cuspid occurs in an edentulous jaw and lies in the line of arch along the alveolar crest, every effort must be made to retain as much bone as possible since they provide part of hard tissue of denture bearing area.