Impaction.pptx

Impaction BY DR. SHIVARAJ W

1. IMPACTION Prof.Dr.Shivaraj.S.Wagdargi Dept . of Oral and Maxillofacial Surgery

2. Contents : Definition Theories and mechanisms of tooth impaction Classification - indications – contraindications Anatomical landmarks Assessment of Impacted teeth Partly erupted and unerupted mandibular third molar Flap designs Lingual split bone technique Operative procedure Surgical management Complications

3. INTRODUCTION ORIGIN – LATIN– IMPACTUS. Impactus : Cessation of eruption caused by physical barrier / ectopic eruption. An impacted tooth is partially erupted or unerupted tooth and is positioned against another tooth , bone or soft tissue so that its further eruption is unlikely and will not eventually assume a normal arch relationship with the other teeth or tissues

4. DEFINITION IMPACTED TOOTH : According to ROUNDS (1936) : Impacted tooth is one which is embedded in the alveolus so that its further eruption is prevented According to ARCHER(1975)- It is a tooth which is completely or partially unerupted and is positioned against another tooth, bone or soft tissue so that its further eruption is unlikely, described according to its anatomic position . According to LYTTE (1979) : Impacted tooth is one that has failed to erupt into normal functional position beyond the time usually expected for such appearance . Eruption is prevented by adjacent hard/ soft including tooth bone or dense soft tissue According to ANDERSON ( 1997) : Impaction is cessation of tooth caused by a clinically or radiographically detectable physical barrier in the eruption path or by an ectopic position of tooth

5. 2. MALPOSED TOOTH : It is a tooth, unerupted /erupted which is in abnormal position in the maxilla/ mandible 3. UNERUPTED TOOTH : It is a tooth not having perforated the mucosa. 4. ODONTECTOMY: It is the term used for the removal of partly erupted or unerupted teeth or retained roots that cannot be extracted by forceps technique and therefore must be removed by surgical excision .

6. Theories & mechanisms of tooth impaction - Durbeck

7. THE MOST COMMONLY IMPACTED OR UNERUPTED TEETH ARE :- MAND. & MAX. THIRD MOLARS AND MAX. CANINES Impacted teeth seen in the following order of frequency ( According to ARCHER ) Maxillary 3 rd molar Mandibular 3 rd molar Maxillary bicuspid Mandibular bicuspid Mandibular cuspid Maxillary cuspid Maxillary central incisors Maxillary lateral incisors

8. PARTLY ERUPTED AND UNERUPTED MANDIBULAR THIRD MOLAR

9. CLASSIFICATION – Impacted third molars are classified according to the position of their long axis of the 2ndMolar 1.Long axis of the impacted tooth in relation to the long axis of the 2nd molar angulation Winter’s classification(1926) : Based on angulation: VERTICAL- 38% MESIOANGULAR- 43% HORIZONTAL – 3% DISTOANGULAR – 6%

10. These may occur simultaneously in: BUCCOANGULAR LINGUOANGULAR INVERTED TORSOVERSION

11. WINTER’S SUB CLASSES The angle between the occlusal plane or line parallel to it and the longitudinal axis of the impacted third molar, in turn, allowed objective classification of the third molars within the Winter subclasses as follows:

12. 2.Pell & Gregory(1933), which includes portion of George B Winter’s classification(1926) : Anterior – Posterior anatomical space – acc. to the anteropost space between 2 nd molar & ant. border of ramus . - CLASS-I : E nough space to accommodate the eruption of a mand 3 rd molar . CLASS-II : P artial lack of space CLASS-III : complete lack of space because the ramus arises directly posterior to 2 nd molar

13. B. RELATIVE DEPTH OF THE 3 RD MOLAR IN THE BONE – the degree of difficulty increases as the depth of the tooth in the bone increases POSITION A : the highest portion of the tooth is on the a level with/ above occlusal line POSITION B : the highest portion of the tooth is below occlusal plane but above the cervical line of the 2 nd molar POSITION C : the highest portion of the tooth is below the cervical line of the 2 nd molar teeth

14. 3. MEDIAL- LATERAL POSITION OF THE 3 RD MOLAR The position of the 3 rd molar in relation to the 2 nd molar to the buccal aspect ( directly behind the second molar) or to the lingual aspect (palatal in the maxilla) of the 2 nd molar 4.ACCORDING TO THE NATURE OF OVERLYING TISSUE : Soft tissue impaction Partially bony impaction Fully bony impaction

15. 5.SUPERIOR – INFERIOR POSITION OF THE 3 RD MOLAR : the position of 3 rd molar in the depth of skeleton of the mandible or maxilla in relationship to 2 nd molar CROWN-to-CROWN relationship CROWN-to-CERVIX relationship CROWN-to-ROOT relationship

16. KILLEY & KAY CLASSIFICATION

17. INDICATIONS FOR THERAPEUTIC REMOVAL OF IMPACTED MAND. 3 RD MOLAR Peterson advocated that ,’ The ideal time for removal of impacted 3 rd molar is after the roots of the teeth are 1/3 rd formed and before they are 2/3 rd formed.’ Peterson considered the indication for removal of impacted teeth to be to: Periodontal diseases Dental caries Pericoronitis Root resorption Odontogenic cysts and tumors Pain of unexplained origin Fracture of mandible To facilitate orthodontic treatment.

18. ANATOMICAL LANDMARKS

19. THE MANDIBLE In many instances the lingual bone consists of a thin cortical plate less than 1 mm in thickness. Extraction can be facilitated by removal of this thin lingual cortical plate. This principle is employed in the lingual split bone technique

20. INFERIOR ALVEOLAR NERVE & VESSELS The greatest surgical anatomical concern arises if the canal overlaps with an impacted third molar. Usually, the canal will be inferior to and / or buccal to the impacted mandibular third molars. Howe & Poyton & Pogrel described the probable characterization of the radiographic image of the relationship of an impacted 3 rd molar to the inferior alveolar canal The canal maybe at the same level as the 3 rd molar but not in contact At the area of overlap, the canal will appear without change of dimension If the tooth and the canal are in contact, the margins of the canal will appear crisp but changed in dimension If the neurovascular structures pass through or between the roots, the canal will not be distinct There maybe a radiolucency denoting a distortion of the roots due to the presence of canal. Distinct lines of the canal and of the roots indicate an overlaywithout encroachment Narrowing of the canal indicates displacement of the canal by roots of the tooth A blending of the structures indicates that the roots surround the canal and its contents

21. Retromolar Triangle

22. LINGUAL NERVE The lingual nerve maybe hidden beneath or in the mucosa lateral to the location of the mandibular 3 rd molar near the crest in an abnormal, superior position. According to KISSELBACH & CHAMBERLAIN ‘ The lingual nerve maybe located at and sometimes slightly superior to the crest of the bony ridge medial to the mandibular 3 rd molar region and only 1-2mm towards the midline in the lingual soft tissue .’

23. On an average the lingual nerve is found about 0.6 mm medial to the mandible and about 2.3 mm below the alveolar crest in the frontal plane.

24. Mylohyoid Nerve This nerve leaves the inferior alveolar nerve just before the it enters the mandibular foramen . It then penetrates the spheno -mandibular ligament and proceeds close to the mandible in the mylohyoid groove . The nerve may be damaged during lingual approach for the removal of impacted mandibular third molar

25. PRE-OPERATIVE RECOGNITION OF FACTORS COMPLICATING THE OPERATIVE PROCEDURE 1.The state of eruption or level of the tooth Tissue impaction Bony impaction 2. The angulation and position of the tooth 3. Relationship of the 2 nd molar to ascertain whether the tooth is locked below the crown of 2 nd molar 4. Distance between the ascending ramus and distal surface of the 2 nd molar should be determined

26. 5 . Appearance of roots- number, shape and size 6. Condition of the tooth 7. The bone along the mesial surface of the tooth  infected or destroyed and necessitates extraction of 2 nd molar 8. Size of the follicular space  narrower the space, more difficult the procedure will be 9 . Presence of cyst

27. RADIOLOGICAL INTERPRETATION ROOT PATTERN

28. RELATIONSHIP OF INFERIOR ALVEOLAR NERVE TO THE ROOTS OF THE THIRD MOLAR. Darkening of root Deflection of root Narrowing of root Dark & Bifid apex Roots impinge on canal. Density of roots - altered Close proximity to root / tooth Division - bucally , lingually or both Deep grooving or perforation of root into the IAC Double periodontal membrane shadow

29. Interruption of white Narrowing of canal Diversion of canal line of canal Deep grooving of root /tooth in the canal Displacement of root and canal towards each other. Hue glass appearance Close proximity to root / tooth

30. WINTER’S LINES OR WAR LINES. Position and depth of impacted tooth : This is determined by a method described by George Winter. In this technique three imaginary lines are drawn on the radiograph.

31. Difficulty Index for removal of impacted mand third molars - Pedersen 1988 CLASSIFICATION DIFFICULTY INDEX VALUE ANGULATION Mesioangular 1 Horizontal / transverse 2 Vertical 3 Distoangular 4 DEPTH Level A 1 Level B 2 Level C 3 RAMUS RELATIONSHIP / SPACE AVAILABL E Class I 1 Class II 2 Class III 3 Difficulty index Very difficult : 7 to 10 Moderately difficult : 5 to 7 Minimally difficult : 3 to 4

32. WHARFE’S ASSESSMENT Winter's classification Horizontal 2 Distoangular 2 Mesioangular 1 Vertical 0 Height of mandible 1-30mm 0 31-34mm 1 35-39mm 2 3.Angulation of 3rd molar 1- 59° 0 60 -69° 1 70 -79° 2 80 -89° 3 90° & above 4 4. Root shape- Root development Favourable curve 1 Unfavourable curve ( less than 1/3 complete) 2 Complex ( more than 2/3 complete) 3

33. 5.Follicle Normal Possibly enlarged 1 Enlarged 2 6. Path of exit Space available Distal cusp covered 1 Mesial cusp covered 2 Both covered 3 TOTAL SCORE 33

34. SURGICAL MANAGEMENT - Steps in surgical removal : John Tomes 1849 – First to describe surgical access

35. DIFFERENT TYPES OF INCISIONS

36. BONE REMOVAL

37. BONE REMOVAL BUR TECHNIQUE ( a)Postage stamp technique (b)Moore and Gillby’s guttering technique (c) Bowdler Henry’s Lateral trephination(1969)-for germectomy , partialy formed and unerupted third molar(9-18 years age ) CHIESEL AND MALLET ( a) through Buccal approach (b) Lingual split technique

38. LINGUAL SPLIT TECHNIQUE – KELSEY FRY- Modified D istolingual Splitting T echnique

39. Surgical steps Incision  starting in the buccal sulcus and extended upwards to the distal aspect of the 2 nd molar Incision courses backwards behind 2 nd molar distobuccally over the external oblique ridge Flap elevation is done bucally and lingually A vertical stop 5mm in height made with chisel in the buccal cortex distal to 2 nd molar A second vertical stop about 4mm distobuccal to 3 rd molar crown join the two cuts  buccal plate covering crown is removed.

40. 5. When completed, the rectangular window should permit insertion of elevator 6. Then, chisel is inserted on the inside of the lingual plate at the 45° to the upper border with its cutting edge parallel to the external oblique line and bevel facing lingually. 7. Few light taps using mallet – separate the lingual plate from the alveolar bone making it to hinge on the lingual soft tissues 8. Bone which remains distally between the lingual and buccal cut is removed

41. 9 . Removal of the impacted teeth by application of an elevator from the buccal aspect 10 . Wound debridement  smoothening of the lingual plate 11. Mucoperisteal flap returned to its position and fixed with a single suture placed distal to 2 nd molar

42. Complications of Impaction Surgery

43. Complications during the Surgical procedure:

44. Complications during sectioning of tooth- BUR

45. 2.Injury to mandibular canal: If the bur is carried to the full width of the tooth in the superior inferior direction – damage to the canal - severe bleeding & numbness of the lower lip . MANAGEMENT : The entry of the bur is limited to three-fourths of the width of the tooth. The rest of the tooth is separated using an elevator. 3. Breakage of bur: This can occur either due to the application of a heavy pressure or due to the repeated use of the same bur. Used burs should be discarded and a fresh bur used in each case. Binding of the bur in the tooth structure is another reason for fracture.

46. 3.Complications during elevation of tooth 1 . Fracture of impacted tooth/ root 2. Injury to second molar 3. Fracture of mandible: Fracture is caused by the application of excessive tensile or shear forces across the superior border of the mandible in the third molar area Management: Removal of the remaining portion of the impacted tooth followed by fixation of fracture by eyelet wiring and maxillary mandibular fixation or bone plating or other methods of fixation

47. (A) While elevating the tooth; as the crown moves upwards , the roots may be forced downwards with the apices piercing the mandibular canal

48. Post Surgical Sequelae and Complications

49. 2. Edema

50. 3.Trismus :

51. 4. Pain

52. 5. Infection Infection after third molar surgery have been reported to vary from 0.8 to 4.2%. It may develop either in the early or in the late postoperative period . Mandibular sites are more commonly affected.

53. 6 . Alveolar osteitis (Dry socket): Alveolar osteitis  is  inflammation  of the alveolar bone. Occurs where the  blood clot  fails to form or is lost from the socket. This leaves an empty socket where bone is exposed to the  oral cavity , causing a localized alveolar osteitis limited to the  lamina dura   Is associated with increased pain and delayed healing time Oral prophylaxis and controlling gingival inflammation before surgery. Lavaging the surgical site with warm normal saline and placing in the alveolous a 1cm wide ,2-3 cm long iodoform gauze soaked in a medication containing eugenol . The dressing should be changed every 3-4 days as needed. Prophylactic administration of metronidazole in adose of 200 mg eighth hourly starting on the day of the procedure and continued for three days.

54. Surgical removal of mandibular third molar may cause injury of the lingual and inferior alveolar nerve resulting in anesthesia or paresthesia . CAUSES : 1. It may be the result of instrument slippage (e.g. scalpel), 2. Cutting too deeply with a bur (e.g. while sectioning a tooth), 3. Over-zealous retraction (e.g. of a lingual or buccal flap), 4. Pushing root tips into a canal or foramen 5. Mechanically damaging the canal contents with an instrument 7. Nerve Injury

55. Injury to the inferior alveolar nerve

56. Injury to lingual nerve :

57. CONCLUSION Surgery for removal of impacted third molar surgeries may be associated with several postoperative complications; these complications are best prevented. However , the surgeon should be prepared to manage them should they occur. All third molars need not be removed independent of disease findings and patients need not unnecessarily have to accept adverse consequences associated with the surgery risks and discomforts in the absence of pain, radiographic findings of pathology, and or marked clinical evidence of disease

58. REFERENCES 1. IMPACTED TEETH - Charles C.Alling 2 . TEXTBOOF OF ORAL AND MAXILLOFACIAL SURGERY VOL.2 -Daniel M.Laskin 3. TEXTBOOK OF ORAL AND MAXILLOFACIAL SURGERY - Peterson Vol.1 4. TEXTBOOK OF ORAL AND MAXILLOFACIAL SUREGRY - SM Balaji 5. A PRACTICAL GUIDE TO THE MANAGEMENT OF IMPACTED TEETH - K.George Varghese