Diagnosis and management of Impacted teeth

Prepared by: Osama Ahmad haj

3rd Year Orthodontic Resident

Definition of impaction An impacted tooth : A tooth that is prevented from erupting into its normal

functional position by bone, tooth or fibrous tissue

Ectopic eruption: The emergence or eruption of a tooth in a site located away from its normal location or position, including all three planes of space: vertical, horizontal and anteroposterior. Tooth transposition, is a special type of ectopic eruption

Because impacted teeth do not erupt, they are retained throughout the individual's lifetime unless extracted or exposed surgically

Most Commonly Impacted Teeth

Mandibular 3rd molars. Maxillary 3rd molars. Maxillary cuspids . Mandibular 2nd bicuspids. Maxillary 2nd bicuspids . Maxillary central incisors. Mandibular 2nd molars .

Causes of multiple failure of eruption

I) Impacted Upper Canines• A canine that is prevented from erupting into its normal functional

position by bone, tooth or fibrous tissue.• The palatal impaction of canines presents a special challenge in practice

of orthodontics. Three questions that immediately come to the mind of the clinician after identification of an impaction are:

Where, specifically, is the tooth? What is the appropriate treatment? How long will it take to align the impacted tooth?

Eruption of maxillary canine

1. Has long path of eruption from the infra-orbital place along the roots of upper laterals causing ugly duckling space which resolve later, and then pass along the buccal surface of the primary canine .

2. Upper canine erupts at 11-12yrs.

3. 3's palpable in buccal sulcus by 8-10 yrs. (Ferguson, 1990 )

Prevalence o Developmentally absent 3's: 0.08% (Brin et al, 1986)o Impacted 3's: 2% (Ericsson, 1986)o F:M = 70%:30%o Unilateral: bilateral = 4:1o Palatal: 61%; in line of arch: 34%; buccal: 4.5% (Mandal, 2000, Brin et

al, 1986)o Associated with peg lateral incisors (Brin et al 1986)o High incidence associated with CI II div 2 malocclusions (Moosy, 1994)

Etiology Localized

• An long and tortious eruptive path.

• Earlier development than adjacent lateral incisors.

• Small or developmentally absent lateral incisors.

• Trauma with displacement of tooth bud.

• Intra-alveolar Obstruction.• Retained deciduous teeth.• supernumerary tooth or

odontome.• Pathology, such as a

dentigerous cyst.• thickened mucosa

following early extraction of deciduous teeth (particularly .

• Dental crowding.

Systemic • Endocrine deficiencies. • Febrile disease. • Irradiation .

Genetic• Heridetity .• Malposed tooth germ. • Presnse of an alveolar

cleft .

Theories of impaction :• Two main theories have been proposed :A ) Guidance theory : underlines a role of the lateral incisor root in guiding the erupting canine crown in the proper direction towards the dental arch. Evidences:• With small or developmentally absent lateral incisors, the

incidence are three times (Becker)• Associated with peg lateral incisors (Brin et al 1986)• High incidence associated with CI II div 2 malocclusions

(Moosy, 1994)

B) Genetic theory: (Peck et al., 1994, 1995),

The palatal displacement of the canine is genetically determined. This theory is supported by other dental anomalies frequently

occurring in patients with the ectopically erupting canines, so-called microsymptoms (e.g. small teeth, enamel hypoplasia, aplasia of second premolars, infraocclusion of primary molars, etc.)

Occurrence with specific race Occurrence in family Occurrence in female more than male Occurrence with specific syndrome Occurrence unilateral: bilateral is 4:1

Diagnosis of unerupted upper canine

A ) History and examination : Practitioners should suspect ectopia if the canine is not palpable in

the buccal sulcus by the age of 10-11 years, if palpation indicates an asymmetrical eruption pattern or the position of adjacent teeth implies a malposition of the permanent canine.

The patient with an ectopic maxillary canine must undergo a comprehensive assessment of the malocclusion, including accurate localization of the canine

B ) Inspection Clinical signs of impacted 3s :• Delayed eruption.• Asymmetrical eruption.• Prolonged retained of C.• Absence of buccal bulge at age of 10 years.• Presence of palatal budges.• Angulated or flared laterals.• Change colour of centerls or laterals .

C) Palpation and percussion :• Palpation of the upper canines is a vital step in assessing

the developing dentition. • Deciduous canines or adjacent permanent teeth should

be checked for mobility, tenderness and vitality.

D) Diagnostic imaging of unerupted teeth

Radiography • The use of various techniques has been advocated for localization of impacted

canines including:I. Right Angle Technique (Broadway & Gould, 1960) - (Coupland, 1987).

II. Horizontal Parallax Technique “ SLOB Rule” (Clark, 1909) .

III. Vertical Parallax Technique (Richards 1952, Rayne 1969, Keur 1986).

IV. CT scans (Ericson & Kurol, 1987).

V. Cone Beam Computed Tomography (CBCT).VI. The single panoramic radiograph .

Right Angle Technique & Tube Shift Technique :

A periapical film will identify the location of an object vertically and in a horizontal (mesiodistal) direction. However, we cannot tell where the object is located buccolingually, since the periapical film is two-dimensional. Therefore, we need another method for locating objects in a buccolingual direction. The two primary methods of determining the buccolingual location of objects are:

1. Right-Angle Technique (Occlusal projection):

Primarily identifies buccolingual location, but may also confirm mesiodistal location seen on periapical

2. Tube-shift Technique (SLOB rule, Clark’s rule):

Utilizes two films with different horizontal or vertical angulations

I. Right Angle Technique • Once you have identified an object on the periapical film, you can

take an occlusal film with the beam at a right angle (perpendicular) to the direction of the beam for the periapical. The beam may also be perpendicular to the film, especially in the mandible. The occlusal film below shows that the impacted canine is lingually positioned.

II. Tube Shift Localization “SLOB Rule” Same Lingual Opposite BuccalThe SLOB rule is used to identify the buccal or lingual location of

objects (impacted teeth, root canals, etc.) in relation to a reference object (usually a tooth). If the image of an object moves mesially when the tubehead is moved mesially (same direction), the object is located on the lingual. If the image of the object moves distally when the tubehead moves mesially (opposite direction), the object is located on the buccal.

Horizontal Vs. Vertical Tube ShiftHorizontal Tube Shift: When the tube head is moved mesially, the beam must be directed more distally (from the mesial). If the tube head is moved distally, the direction of the beam must be more towards the mesial (from the distal).

Vertical Tube Shift: The SLOB rule also works for movement of the tube head in a vertical direction. Downward movement of the tube head requires that the beam be directed upward and when the tube head is moved upward, the beam must be directed downward

Horizontal parallax 1) Upper standard occlusal (midline view) and periapical (centered on the canine region) OR 2) Tow periapicals (one centerd on the upper central incisor and the other centered on the canine region )

Example of Horizontal Parallax

• In the second film, when the tube was shifted MESIALLY, the crown of the impacted tooth moved DISTALLY

Example of Horizontal Parallax

• In the second film, when the tube shifted DISTALLY, the crown tip also moved DISTALLY

vertical parallax 1) Upper standards occlusal and a panoramic

OR 2) Periapical and a panoramic radiograph .

Example of Vertical Parallax

In the second film, when the tube was shifted UPWARD, the crown of the impacted tooth moved UPWARD

Vertical / Horizontal Parallax• Increasing the vertical angulation of the X-ray tube from 60-65 to 70-75 ⁰ ⁰

increase the effect of parallax (Jacobs, 1999)

• Horizontal parallax is more accurate than vertical parallax (83% of 3s were correctly located with horizontal vs. only 68% with vertical) (Armstrong et al., 2003)

• DPT overestimates the angulation and underestimates proximity to the midline (Ferguson, 1990)

• 92% of palatal canines can be localized with two periapical radiographs (Ericson & Kurol, 1987)

Cone Beam Computed Tomography (CBCT)

• The best tool for evaluating the status of the impacted canine is the CBCT (3D CT) image since it establishes the link between 2D and 3D imaging. With this three-dimensional (3D) tool, the orthodontist (or any dental specialist) would be able to see the exact status of the impacted canine in question .

• Using CBCT with the maximum data available would help reduce unnecessary radiation exposure.

• In CBCT, there is much better visualization of the roots in their real position (Advantage over 2D radiographs)

CBCT (3D CT)

The single panoramic radiograph

• Chaushu, Chaushu and Becker (1999) have described a method of localizing maxillary canines using only a panoramic radiograph.

•This depends on the fact that objects nearer the x-ray source (and further from the film) project a larger image than objects closer to the film and further from the x-ray source.

• Thus palatal canines will appear larger than buccal canines (remember that the x-ray source from a panoramic radiograph comes from behind the head).

• In the coronal and middle thirds of the adjacent incisor, the ectopic canines that were positioned buccally had a canine-incisor width ratio of 0.78-0.1.11 and the palatal canines a canine-incisor width ratio of 1.5-1.7.

• While not an infallible method of localizing canines, this can be a useful adjunct to other methods and may help to provide a positive diagnostic localization.

Canine-Incisor Index (CII)

E) Position

Relates to prognosis and complexity of aligning canine. Therefore, the aim was to investigate which of the following

radiographic factors might influence the orthodontist decision to expose, and align or remove an impacted upper permanent canine:

I. Canine angulation to the midlineII. Antero-posterior position of the canine root apexIII.Vertical height of the canine crownIV. Canine crown overlap to the adjacent incisor

Study by: N. Stivaros & N.A. Mandall 2000

Root resorption of maxillary lateral Incisors

• Incidence: 12% of cases with impacted canines , CT studies show 48% of laterals demonstrate a degree of root resorption (Ericson and Kurol, 2000).

Walker 2004 used CBCT and showed 67%• CT could be considered when resorption cannot be ruledout from intra-oral films.

Risk factors for resorption of lateral roots:- female, age <14yrs, horizontal palatal canines- advanced canine root development- canine crown medial to midline of lateral incisor

Treatment options According to RCSEng 2016 Husain

and McSherry

1 ) No active treatment/leave and observe • Indications : 1. Patient does not want treatment 2. Canine very displaced, ie high and above roots of incisors 3. No evidence of resorption of adjacent teeth or other pathology 4. Ideally good contact between lateral incisor and first premolar wih good aesthetics 5. Good prognosis for the deciduous canine Radiographic monitoring should take place to rule out cystic

formation (frequency unknown), migration, resorption etc

2) Interceptive treatment by extraction of the primary canine• in carefully selected cases , where the ectopic permanent canine is not severely displaced , there is some evidence that interceptive extraction of the adjacent primary canine can result in an improvement in position of an ectopic permanent canine.

• the patient should be aged between 10-13 years , with better results reported in the absence of crowding .

• if radiographic examination reveals no improvement in the ectopic canines position 12 months after extraction of the primary canine , alternative treatment options should be considered .

  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 

Evidences of interceptive extraction of primary canine

3) Surgical exposure and orthodontic alignment• The case is not suitable for interceptive treatment .• The patient should be well motivated and have good dental health.

• The patient should be willing to wear fixed orthodontic appliance.

• The degree of malposition of the ectopic canine should not be so great that orthodontic alignment is impractical .

• The success of treatment decreases with age in adults .

4) Surgical removal of the ectopic permanent canine• If the patient declines active treatment .• If there is radiographic evidence of early root resorption of the adjacent incisor teeth .( but exposure and alignment of the ectopic canine is usually indicated in cases where severe root resorption of an incisor tooth has occurred necessitating the extraction of the incisor ).

• If there good contact between 2 and 4 “best result”.

5) Transplantation• Where interception has failed and grossly malpositionedcanine.

• ideally with open apex at 13-14 yrs. to aid vitality.• optimal development stage for auto transplantation iswhen the root is 50-75% formed = half to three-quarters complete .• The prognosis should be good for the canine tooth to be transplanted with no evidence of ankylosis .

• The transplanted canine may require root canal therapy to be commenced within 10 days following transplantation.

II) Impacted maxillary central incisors:Definition : Delayed eruption of the permanent maxillary incisor teeth can be considered in the following circumstances:a. eruption of the contralateral incisor occurred more than 6 months earlier.b. the maxillary incisors remain unerupted more than one year after the eruption of the

mandibular incisors.c. There is a significant deviation from the normal eruption sequence (for example, lateral incisors

erupting prior to the central incisor).

Incidence : 0.13 % the maxillary central incisor is the third-most commonly impacted tooth after third permanent

molars and maxillary canines.

Causes of delayed eruption General causes :o Hereditary gingival fibromatosis .o down syndrome .o Cleidocranial dystosis .o CLP. Localized causes :o Crowding .o Delayed exfoliation of primary tooth. o Supernumerary tooth .o Dilacerations. o Abnormal position of crypt .

Investigation of unerupted central incisor

Management of unerupted central incisors

• RCSeng recommandations (Yaqoob et al 2010):

III) Impacted lower second premolar • The mandibular second premolar is one of the most frequently impacted teeth. • The recommended treatment is to extract the second primary molar with or

without removing the bone along the eruption path, to uncover the tooth surgically and move it into the arch by orthodontic treatment.

• . The prevalence of impacted premolars has been found to vary according to age . the overall prevalence in adults has been reported to be 0.5%.

• Premolar impactions may be due to local factors such as mesial drift of teeth arising from premature loss of primary molars; ectopic positioning of the developing premolar tooth buds; or pathology such as inflammatory or dentigerous cyst.

• They may also be associated with over retained or infraocclusal ankylosed primary molars or with syndromes such as cleidocranial dysostosis .

Management of infra-occluded primary second molars.

References : • Husain J, Burden D, McSherry P. Management of

the palatally ectopic maxillary canine. London: TheRoyal College of Surgeons of England, Faculty ofDental Surgery, 2010.

• Surgical and orthodontic management ofimpacted maxillary canines .Vincent G. Kokich,

• Bishara SE. Impacted maxillary canines: areview. Am J Orthod Dentofacial Orthoped1992; 101: 159–171.

• Ericson S, Kurol J. Longitudinal studyand analysis of clinical supervision ofmaxillary canine eruption. CommunityDent Oral Epidemiol 1986; 14: .

• Becker A, Chaushu S. Success rate andduration of orthodontic treatment foradult patients with palatally impactedmaxillary canines. Am J OrthodDentofacial Orthop 2003; Nov 124

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