Canine Impactions Ectopic Eruption Lecture 6 Ingrid Reed DDS, MS Department of Orthodontics and Dentofacial Orthopedics IMPACTIONS / ECTOPIC ECTOPIC means out of the normal position. Malposition of a permanent tooth bud can lead to eruption in the wrong place. Contrast this with IMPACTED. By definition IMPACTED TEETH are teeth that are so closely lodge in the alveolar bone as to be unable to erupt. Usually third molars and maxillary cuspids. Impacted teeth may or may not be ectopic

Impacted vs. Ectopic eruption Condition of being firmly lodged (impacted in alveolar bone) or wedged by a physical barrier, usually other teeth, so it is prevented from erupting Ectopic eruption Located away from the normal position

Eruption process Permanent tooth erupts Resorption of overlying bone Resorption of 1° tooth roots Eruption through gingiva

Interference with eruption Ectopic eruption of permanent tooth Undermining resorption of the 1° tooth Non- resorption of 1° roots, may be result not cause Supernumerary teeth – remove as indicated Heavy fibrous gingiva – may need to expose tooth Sclerotic bone – may need to expose tooth Ankylosed tooth Lack of space – consider serial extraction or orthodontics (age/crowding dependent) Causes of Interference with eruption Mosby Orthodontic Review page 19 Ectopic eruption is when a tooth erupts away from the normal position. Multifaceted etiology: Abnormal position of tooth bud in order of prevalence Maxillary first molars Maxillary canines Mandibular canines Maxillary premolars Mandibular premolars Maxillary lateral incisors Ectopic eruption of permanent tooth an cause two things: Undermining resorption of the primary tooth as in the case of first molars or Non-resorption of primary roots usually Mandibular second 1° molars (due to size) and Maxillary second 1° molars due to palatal root.

Normal Development of Maxillary Canines Age 3 – located high in maxillary bone –mesially & lingually directed crown Intrabony migration – lateral roots – ‘ugly duckling’ Spontaneous closing of midline diastema as canines simultaneously upright and erupt

Palpable high in the buccal vestibule 4-6 months Development (calcification) begins high in the maxilla 6 years Crown completed 10 years Palpable high in the buccal vestibule 11-13years Eruption 14 - 15 years Root completed Normal development of canine

Prevalence of Maxillary Canine Impaction Maxillary canine 2nd most frequently impacted tooth Third molars most frequently impacted Maxillary 50 times greater than mandibular Palatal versus buccal - range 2:1 to 12:1

Etiology - Maxillary Canine Impaction Availability of space in arch Eruption path Horizontal angulation of tooth Trauma to 1° tooth bud Disturbance in eruption sequence Rotation of tooth buds Premature root closure

Impacted third molars and canines

Maxillary Canine Impaction – Diagnostic Problem Usually last tooth to replace primary tooth Fewer radiographs taken at recall – bitewings may not show canines Need knowledge of crown development, root development and eruption

Impacted Maxillary Canines The most opportune time to observe the maxillary canines beginning their eruption and detect an eventual impaction is when children are ~ 8 - 9 years of age, when the maxillary canines migrate labially

Overretention of Primary Canines Canine erupts 11-13 years Primary canine not exfoliated, overretention may be result of, not cause of, ectopic position of canine Permanent canine has not precipitated vertical resorption of the primary tooth’s root Canine crown inclined too far mesially Canine crown having slipped over the root of the permanent lateral incisor, is deprived of the eruptive guidance of the lateral incisor’s distal surface

Extraction of Primary Canines Canines begin to deviate from a normal eruptive position in patients ~9 years of age If permanent canine path is errant, extract primary canines at age 10. Teeth take the path of least resistance Improvement usually seen in 6-18 months

Extraction of Primary Canines Degree of horizontal angulation important Study by Ericson an Kurol 78% of canines changed angulation within 18 months of 1° canine extraction 91% if tip of canine cusp had not passed midline of lateral root Must have space for canine to erupt- maintain or create after primary extraction.

Sequence of Eruption Permanent Teeth MAXILLARY MANDIBULAR First molar Central incisor Lateral incisor First premolar Canine Second premolar Second molar

Clinical Signs of Maxillary Canine Impaction Failure to palpate canine bulge in buccal vestibule by 10 years Immobility of the deciduous canine Palatal bulge indicating possible underlying canine Increased mobility, non-vital central or lateral incisors Inadequate space within the dental arch for canine eruption Flared lateral incisors – can also be normal Asymmetry of eruption Impacted maxillary canines in individuals > 40 years susceptible to ankylosis Failure of movement in an adolescent indicates ankylosis

Lack of Space

Lack of space for canines NA Noah Armstrong Lack of space for canines

9 years 4 months NA Note need for several extraction

Screening panoramic radiograph Dental age 8-9 Full eruption of Maxillary central and lateral incisors Mandibular central and lateral incisors All four first molars Anytime prior with cause

Radiographic Signs of Probable Canine Impaction Long axis of the canine is angled more than 10 ° to the vertical plane. The greater the angle the more likely a problem. 25° - impaction Canine overlaps the lateral or central incisor root Parallax technique shows buccal/palatal position Clark’s rule – as change horizontal position of tube head, lingual position moves in same direction as tube, buccal moves in opposite direction.

Clark’s rule – Horizontal change The lingual object moves in the same direction as the x-ray source The buccal object moves in the opposite direction of the x-ray source because it is farther away from the film than the root of the lateral incisor

Normal development

Megan Ehrnman

Canines impacted with resorption of lateral roots

Central and lateral incisor roots resorbed

Angulation of the lateral and central due to pressure of the canine

10/31/05 Age 9 yrs 3 mos Patient A Canine impactions and impacted premolars due to lack of space Recommend TE deciduous canines and 1st primary molar on right and 2nd primary molar on left. Will later TE 1st premolar on left and leave in Class II on left. Distalizing the 1st molar could cause second molar impaction Patient did nothing

Patient A 40°

2 yrs 5 mo later Age 11 yrs. 8 mos Patient A

Age 12yrs. 7 mos Patient B The first thing you should do is extract the deciduous canines, there is no guarantee that the canines will come in but if you do nothing there is a much greater chance they will be impacted, especially when crossing over the roots of the laterals.

Age 16 yrs 10 months Patient B 4 years 3 months later Age 16 yrs 10 months Patient B Refer to orthodontist

Horizontal impactions, note mandibular canine

Mandibular canine impactions Amy Risch Mandibular canines can be impacted as well

Management of Impacted Canines Extract Deciduous Canine Age 10 May help normalize eruptive path in palatally displaced canine Radiographic improvement in 6-18 months No Treatment Poorly motivated patient Inform of resorption risk and cystic change within canine follicle Monitor radiographically every 12 months Orthodontic Alignment Following surgical exposure Gold chain bonded to the tooth Space created TPA in place Surgical Removal Very unfavorable canine position Poorly motivated patients Orthodontic treatment contraindicated Severe crowding (substitute 1st premolar)

Impacted teeth - considerations Surgical exposure Attachment to the tooth Orthodontic mechanics to bring the tooth into the arch

KF Case of palatally impacted canine

KF Canine palatally located 4/13/07

KF 12/1/07

KF 8/7/08

KF

KF

KF 2-2009

Impacted second molar

Ectopic Eruption Out of normal position

Ectopic Eruption Maxillary first molars Maxillary canines Mandibular canines Maxillary premolars Mandibular premolars Maxillary lateral incisors

Ectopic eruption Malposition of a permanent tooth bud Eruption in the wrong place Most common – maxillary first permanent molars Ectopic eruption of other teeth rare but can lead to transposition pgs 139, 249-252,453-458

Ectopic eruption Permanent tooth causes resorption of tooth other than the one it is supposed to replace or Resorption of an adjacent permanent tooth Can be 1st permanent molar or lateral incisor causing resorption of primary canine

Lateral incisors Ectopic eruption causes resorption of primary canine – indicates lack of space Loss of only one primary canine can cause midline shift – need to maintain lateral incisor position with appliance or Extract contralateral canine Loss of mand. 1° canines causes incisors to tip lingually with loss of arch perimeter Space analysis important – passive LLA or active LLA

Ectopic Maxillary First Molar Prevalence 2-6% (20-25% if cleft lip/palate) Etiology Crowding / large crown / mesial eruption MANAGEMENT OBSERVE Active Treatment May correct spontaneously Rarely after age 8 years Brass wire or elastic separator – mild cases Distalizing appliances more serve cases Extract primary if pulpal involvement – space maintainer or regainer

Age 8yr. O months Patient Y Zumwalt 495-5-27 Ectopic eruption of maxillary laterals (resorbing maxillary canines) Mandibular lateral resorbing canine Age 8yr. O months

Patient Y Zumwalt 495-5-27

8 years 2 months Patient Z Emily Lopez 453-5-63

6 weeks Patient Z corrected

Missing 2nd premolars Age: 7 years 8 months Morgan Brown 515-5-41 Consider removing 2nd primary molar and allowing 1st permanent molar to move mesially Age: 7 years 8 months

DOB 11-1-02, Pano 7-20-10 age 7 years 8 months W.E. Evans, W.

W.E.

Transposed Teeth S.N.

Early Loss of Primary Teeth Early loss of 2nd 1° molar Mesial drift of first permanent molar Greater if no occlusal forces are on it Early loss of 1° first molar or canine Distal drift of incisors Force from active contraction of transseptal fibers Pressure from the lips and cheeks pgs – 139-141