impacted teeth

DEFINITIONS:

IMPACTED TOOTH

A TOOTH THAT IS COMPLETELY OR PARTIALLY UNERUPTED & IS POSITIONED AGAINST ANOTHER TOOTH, BONE OR SOFT TISSUE SUCH THAT ITS FURTHER ERUPTION IS UNLIKELY DESCRIBED ACCORDING TO ITS ANATOMIC POSITION.

MALPOSED TOOTH

A TOOTH UNERUPTED OR ERUPTED, WHICH IS IN AN ABNORMAL POSITION IN THE MAXILLA OR THE MANDIBLE.

UNERUPTED TOOTH

A TOOTH NOT HAVING PERFORATED THE ORAL MUCOSA.

ORDER OF FREQUENCY OF IMPACTION

Maxillary Third Molars

Mandibular Third Molars

Maxillary Cuspids

Mandibular Bicuspids

Mandibular Cuspids

Maxillary Bicuspids

Maxillary Central Incisors

Maxillary Lateral Incisors

THEORIES OF IMPACTION

Mendelian theory

Evolutionary reduction in the size of the maxilla or the mandible

Phylogenetic theory

Evolution of Masticatory habits- leading to Withdrawal / elimination of stimulus.

Softer and refined foods / fibrous food / Uncooked meat

Orthodontic theory

Loss of anterior component of force.

Endocrine Imbalance theory

Pathologic theory

ETIOLOGY

SYSTEMIC

Prenatal

HeredityMiscegenation

Postnatal Causes

RicketsAnemiaCongenital SyphilisTuberculosisEndocrine DysfunctionsMalnutrition

Rare Causes

Clediocranial DysostosisOxychephalyProgeriaAchondroplasiaCleft Palate

LOCAL

Irregular adjacent teeth

Increased Density of surrounding bone

Long standing chronic Inflammation

Lack of space due to under developed jaws

Retained primary dentition

Premature loss of permanent dentition

COMPLICATIONS ARISING FROM RETAINEDIMPACTED TEETH

Persistent Local InfectionsAcute / Chronic alveolar abscessesPericoronal infectionsChronic suppurative osteitisNecrosisOsteomyelitis

Pathological Resorption of adjacent teeth

Pathological conditions like cysts and tumors

Pain (Facial pain of Unknown origin)

Fractures of the jaws due to weak spot

INDICATIONS FOR REMOVAL OF IMPACTED TEETH

Recurrent Pericoronitis- (Indicated / contraindicated)

Unrestorable caries

Periodontal disease (prophylactic)

Obscure Oro-facial pain

Previous attempted extraction

Prosthetic considerations

Orthodontic considerations

PRE-OP ASSESMENT OF IMPACTED 3RD MOLAR

CLINICAL:-

Small mouth, mandibular retrusion-limited access

Large mouth, mandibular protrusion-good access

EXTERNAL OBLIQUE RIDGE & RELATION TO 3RD MOLAR:-

Ridge behind tooth-good access

Ridge along tooth-poor access

RADIOLOGICAL ASSESMENT OF IMPACTED 3RD MOLARS

Extraoral Lateral Oblique: -

Shows amount of bone below 3rd molar

Orthopantomograph: -

Relation of tooth apex to canal

Intraoral periapical: -

Paralleling cone (Minimal distortion)Bisecting angle

Access: - White line of External Oblique Ridge

Vertical- Poor accessHorizontal- Good access

WINTERS WAR-LINESWHITE LINE: -

A line drawn along the occlusal surfaces of the 1st, 2nd & the highest point of the third molar. This line shows the Axial Inclination of the 3rd Molar.

Mesioangular, Distoangular, Horizontal, Vertical.

WINTERS WAR-LINESAMBER LINE: -

A line drawn from the bone distal to the third molar to the Interdental septum (crest) between the 1st and the 2nd molar.

This line shows the amount of tooth seen on exposure.

WINTERS WAR-LINESRED LINE: -

A line drawn from the amber line to an imaginary point of application of an elevator. Denotes the depth at which the tooth lies within the mandible. 5mm-under G.A., 9mm- extraoral approach.

ROOT PATTERN OF 3RD MOLAR

Dilacerated, hooked, unfavorable curvature,dancing roots ,hypercementosed, bulbous

SHAPE OF THE CROWN

Large crowns difficult to removeSmall crown easy to remove

TEXTURE OF INVESTING BONE

Increase in age- bone more sclerosed and less elasticAlso note size of cancellous spaces & density of bone structure.

POSITION AND ROOT PATTERN OF THE 2ND MOLAR

Distal tilt in 2nd molar - difficult impactionConical roots -more chances of accidental luxation

RELATION SHIP OF ROOT TO CANAL

Related but not involving the canal

SeparatedAdjacentSuperimposed

Related to changes in the roots

Darkening of rootDark and bifid rootNarrowing of rootDeflected root

Related with changes in the canal

Interruption of linesConverging canalDiverted canal

PELL & GREGORY’S CLASSIFICATION

A. Relation of the tooth to the ramus of the mandible and the second molar

CLASS I Sufficient amount of space between ramus and distal side of 2nd molar

to accommodate the mesio-distal width of 3rd molar

CLASS IISpace between ramus and distal side of 2nd molar less than the

mesio-distal width of the 3rd molar

CLASS IIIAll or most of the third molar is located within the ramus of the

mandible.

CLASS I CLASS II

CLASS III


B. Relative depth of the third molar in the bone.

POSITION AHighest portion of tooth is on a level with

or aboveocclusal line

POSITION BHighest portion of 3rd molar below

occlusal line but above cervical line of 2nd molar

POSITION CHighest portion of 3rd molar below

cervical line of 2nd molar

POSITION A

POSITION C

POSITION B


C. The position of the long axis of the impacted mandibular third molar in relation to the long axis of the second molar (Winter’s classification)

Mesioangular Distoangular Vertical Horizontal Inverted Buccoangular Linguoangular

SURGICAL MANAGEMENT

John Tomes (1849) – first to describe surgical access

Steps in surgical removal:

AnesthesiaIncision and mucoperiosteal flapRemoval of boneTooth removalWound debridementArrest of haemorrhageWound closurePostoperative follow-up

MUCOPERIOSTEAL FLAP:

Incision – 3 parts: Anterior, posterior & intermediate limb

Not to be extended too distally-Bleeding from buccal vessels & other arteriesPostoperative trismus – temporalis muscle damageHerniation of buccal fat padDamage to lingual nerve (lingual extention)

Factors governing planning of incision

Surgical accessHealing of sutured wound – dry socket Periodontal health of II molar – distal pocketSuture line must rest on normal bonePartly visible crown: de-epitheliazation

TYPES OF FLAPS

L – shaped flap

Envelope flap

Bayonet – shaped flap

ELEVATION OF THE FLAP

Good and adequate exposure

Avoid button holing

Understanding of the anatomy in that region

Adequate retraction: self-retaining retractors (thimble)

BONE AND TOOTH REMOVAL

Chisel, bur or combination techniques

Bur technique:

Rose-head bur – Gutter around the distal and buccal aspect

(Moore & Gilby’s technique)

More amount removed around the point of application

Under copious saline irrigation – thermal necrosis

Chisel technique through buccal approach:

Immobilize mandible – prop

Follow bone trajectories – parallel to long axis of the bone

Vertical stop cut first – 3 to 5 mm distal to II molar

Oblique cut – removal of wedge to expose the tooth

Further removal for point of application

LINGUAL SPLIT TECHNIQUE – KELSEY FRY

Useful for lingually placed III molar

Similar incision and limiting cuts

Removal of distolingual bone parallel to ext. oblique ridge

Fracture of the lingual plate – removal of wedge

Tooth elevated lingually

Higher incidence of lingual nerve damage

Advantage: saucer shaped cavity – retains clot

TOOTH DIVISION TECHNIQUE:

Horizontal, distoangular impacted teeth

To avoid removal of large amount of bone

Tooth can be divided vertically, horizontally, and obliquely

LATERAL TREPENATION TECHNIQUE:

Described by Bowdler Henry

Orthodontic purpose – avoid malocclusion

Modified S-shaped incision

Buccal cortical plate is trephined over III molar crypt

Tooth removed along with follicle

COMPLICATIONS OF REMOVAL:

Dry socket – 10 to 30 %

Damage to inferior alv. canal, lingual & mylohyoid nerves with impaired sensation – 2 to 3 %

Pocket formation distal to II molar

Infection, pain & swelling – 50%

Damage to adjacent tooth

Deeply impacted tooth in edentulous jaw – fracture

IMPACTED MAXILLARY THIRD MOLARS


Classification based on anatomic position:

A. Relative depth of the impacted maxillary third molar in bone:

Class A: The lowest portion of the crown of the impacted maxillary third molar is

on a line with the occlusal plane of the second molar.

Class B: The lowest portion of the crown of the impacted maxillary third molar is

between the occlusal plane of the second molar and the cervical line.

Class C: The lowest portion of the crown of the impacted maxillary third molar is

at or above the cervical line of the second molar.


B. The position of the long axis of the impacted maxillary third molar in relation to the long axis of the second molar:

Vertical InvertedHorizontal BuccoangularMesioangular Linguoangular Distoangular

C. Relationship of the impacted maxillary third molar to the maxillary sinus:

Sinus approximation (S.A.): no bone, or a thin partition

No sinus approximation (N.S.A.): 2 mm or more

CLASS A

CLASS B

CLASS C

SURGICAL TECHNIQUE:

Soft tissue flap: • Incision is made starting beyond the tuberosity in the

hamular notch with No. 12 BP blade. • The mucous membrane overlying the tuberosity is

incised from the distalmost portion of the tuberosity forward until the midpoint of the distal surface of the second molar.

• The incision is continued buccally around the neck of the second molar to the interproximal space between the first and second molar and then towards the mucobuccal fold at 45-degree angle.

2. Removal of overlying bone:

Bone not dense- can be removed with chisels /ronguers

Avoid driving the tooth into the sinus / pterygomaxillary space

No need of sectioning

Expose the crowns height of contour

3. Removal of impacted tooth: Use of elevators

FACTORS COMPLICATING REMOVAL:

Maxillary sinus approximation

Impacted partly within or immediately above the roots of the second molar

Fusion of third and second molar roots

Abnormal root curvature

Hyper-cementosis

Proximity of the zygomatic process of maxilla

Extreme bone density

Follicular space filled with bone

Trismus

IMPACTED MAXILLARY CUSPIDS

IMPACTED MAXILLARY CUSPIDS

ETIOLOGIC FACTORS:

Hard palate is more resistant Mucoperiosteum of the anterior third of

palate is very dense thick and resistant. Attached more firmly to the bone

Eruption is aided by apical development. Canine root fully formed at the time of eruption

Greatest distance to travel before reaching full occlusion.

Caries or premature loss of primary cuspid

Delayed resorption of primary cuspid

Last permanent tooth to erupt.

Erupt between teeth already in occlusion

Preceded by primary cuspid whose mesiodistal diameter

is much lesser.

POSITION OF IMPACTED MAXILLARY CUSPIDS

Three times more on the palatal sideAlmost always rotated upon their longitudinal axis and are usually in an oblique positionHorizontal positionFound between first and second molars, nose, sinus, orbit

LOCALIZING IMPACTED MAXILLARY CUSPIDS

Clinical : Distinct bulge, deflection of crownsRadiological: IOPA, occlusal view, Shift cone technique

FREQUENT POSITIONS: In the palate, crown located lingual to the upper lateral incisor and root extending posteriorly parallel to bicuspid roots Crown lingual to central incisor and root extending posteriorly parallel to the premolar roots

or between the premolar roots through to the buccal surface Crown on the palatal area and body of the root buccally Crown on the buccal surface and root palatally Entire tooth in the buccal cortical plate Bilaterally impacted either in the palatal process or labially

In the palate, crown located lingual to the upper lateral incisor and root extending posteriorly parallel to bicuspid roots

CLASSIFICATION OF IMPACTED MAXILLARY CUSPIDS

Class I: Impacted cuspids located in the palateHorizontalVerticalSemi vertical

Class II: Impacted cuspids located in the labial or buccal surface of the maxilla

HorizontalVerticalSemi vertical

Class III: Impacted cuspids located in both the palatal process

and labial or buccal maxillary bone

Class IV: Impacted cuspids located in the alveolar process

usually vertically between the incisor and first

premolar

Class V: Impacted cuspids located in the edentulous maxilla

CLINICAL FEATURES:

Clinically absent in the arch beyond the chronological age of eruption

Displacement of adjacent teeth

Presence of swelling in the buccal or palatal mucosa

Formation of fistula

Transformation into follicular cyst

Resorption of adjacent roots leading to mobility

TREATMENT POSSIBILITIES:

Factors governing management Age of the patient Stage of tooth development Position of the impacted tooth Evidence of root resorption of

permanent teeth Compliance

Possibilities of treatment:

Leave in-situ Surgical removal Surgical exposure of the crown Surgical repositioning Surgical transplantation

Factors Relatively easy Relatively difficult

1. Pell & Gregory’s Class.

(a)Horizontal plane

(b)Vertical plane

Class I

Position A

Class III

Position C

2. Overlying impediment Soft tissue Bone

3. Crown Small Large

FACTORS RENDERING MADIBULAR III MOLAR SURGERY EASY / DIFFICULT

4. Roots

(a)Formation

(b)Curvature

(c)Morphology

Incomplete

Favourable

Conical / convergent

Complete

Unfavourable

Long, slender, divergent

5. Follicular space Large Thin and small

6. Surrounding bone Elastic or cancellous Dense or cortical


7. Relationship

(a)II molar

(b)Inf. Alv. Canal

Space distal to

Not related

No space distal to

Related

8. Oral sphincter Large Small

9. Health status Satisfactory Medically comp.


impacted teeth

Healthcare