Presentation on theme: "Canine Impactions Ectopic Eruption"— Presentation transcript:
1Canine Impactions Ectopic Eruption Lecture 6Ingrid Reed DDS, MSDepartment of Orthodontics and Dentofacial OrthopedicsIMPACTIONS / ECTOPICECTOPIC 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
2Impacted 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 eruptingEctopic eruptionLocated away from the normal position
3Eruption process Permanent tooth erupts Resorption of overlying bone Resorption of 1° tooth rootsEruption through gingiva
4Interference with eruption Ectopic eruption of permanent toothUndermining resorption of the 1° toothNon- resorption of 1° roots, may be result not causeSupernumerary teeth – remove as indicatedHeavy fibrous gingiva – may need to expose toothSclerotic bone – may need to expose toothAnkylosed toothLack of space – consider serial extraction or orthodontics (age/crowding dependent)Causes of Interference with eruption Mosby Orthodontic Review page 19Ectopic eruption is when a tooth erupts away from the normal position.Multifaceted etiology:Abnormal position of tooth bud in order of prevalenceMaxillary first molarsMaxillary caninesMandibular caninesMaxillary premolarsMandibular premolarsMaxillary lateral incisorsEctopic eruption of permanent tooth an cause two things:Undermining resorption of the primary tooth as in the case of first molars orNon-resorption of primary roots usuallyMandibular second 1° molars (due to size) andMaxillary second 1° molars due to palatal root.
5Normal Development of Maxillary Canines Age 3 – located high in maxillary bone –mesially & lingually directed crownIntrabony migration – lateral roots – ‘ugly duckling’Spontaneous closing of midline diastema as canines simultaneously upright and erupt
6Palpable high in the buccal vestibule 4-6 monthsDevelopment (calcification) begins high in the maxilla6 yearsCrown completed10 yearsPalpable high in the buccal vestibule11-13yearsEruptionyearsRoot completedNormal development of canine
7Prevalence of Maxillary Canine Impaction Maxillary canine 2nd most frequently impacted toothThird molars most frequently impactedMaxillary 50 times greater than mandibularPalatal versus buccal - range 2:1 to 12:1
8Etiology - Maxillary Canine Impaction Availability of space in archEruption pathHorizontal angulation of toothTrauma to 1° tooth budDisturbance in eruption sequenceRotation of tooth budsPremature root closure
10Maxillary Canine Impaction – Diagnostic Problem Usually last tooth to replace primary toothFewer radiographs taken at recall – bitewings may not show caninesNeed knowledge of crown development, root development and eruption
11Impacted Maxillary Canines The most opportune time to observe the maxillary canines beginning their eruption and detect an eventual impaction is when children are ~ years of age, when the maxillary canines migrate labially
12Overretention of Primary Canines Canine erupts yearsPrimary canine not exfoliated, overretention may be result of, not cause of, ectopic position of caninePermanent canine has not precipitated vertical resorption of the primary tooth’s rootCanine crown inclined too far mesiallyCanine crown having slipped over the root of the permanent lateral incisor, is deprived of the eruptive guidance of the lateral incisor’s distal surface
13Extraction of Primary Canines Canines begin to deviate from a normal eruptive position in patients ~9 years of ageIf permanent canine path is errant, extract primary canines at age 10.Teeth take the path of least resistanceImprovement usually seen in 6-18 months
14Extraction of Primary Canines Degree of horizontal angulation importantStudy by Ericson an Kurol78% of canines changed angulation within 18 months of 1° canine extraction91% if tip of canine cusp had not passed midline of lateral rootMust have space for canine to erupt- maintain or create after primary extraction.
16Clinical Signs of Maxillary Canine Impaction Failure to palpate canine bulge in buccal vestibule by 10 yearsImmobility of the deciduous caninePalatal bulge indicating possible underlying canineIncreased mobility, non-vital central or lateral incisorsInadequate space within the dental arch for canine eruptionFlared lateral incisors – can also be normalAsymmetry of eruptionImpacted maxillary canines in individuals > 40 years susceptible to ankylosisFailure of movement in an adolescent indicates ankylosis
19Lack of space for canines NANoah ArmstrongLack of space for canines
209 years 4 monthsNANote need for several extraction
21Screening panoramic radiograph Dental age 8-9Full eruption ofMaxillary central and lateral incisorsMandibular central and lateral incisorsAll four first molarsAnytime prior with cause
22Radiographic 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° - impactionCanine overlaps the lateral or central incisor rootParallax technique shows buccal/palatal positionClark’s rule – as change horizontal position of tube head, lingual position moves in same direction as tube, buccal moves in opposite direction.
23Clark’s rule – Horizontal change The lingual object moves in the same direction as the x-ray sourceThe 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
28Angulation of the lateral and central due to pressure of the canine
2910/31/05Age 9 yrs 3 mosPatient ACanine impactions and impacted premolars due to lack of spaceRecommend 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 impactionPatient did nothing
32Age 12yrs. 7 mosPatient BThe 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.
33Age 16 yrs 10 months Patient B 4 years 3 months laterAge 16 yrs 10 months Patient BRefer to orthodontist
52Ectopic eruption Malposition of a permanent tooth bud Eruption in the wrong placeMost common – maxillary first permanent molarsEctopic eruption of other teeth rare but can lead to transpositionpgs 139, ,
53Ectopic eruptionPermanent tooth causes resorption of tooth other than the one it is supposed to replace orResorption of an adjacent permanent toothCan be 1st permanent molar or lateral incisor causing resorption of primary canine
54Lateral incisorsEctopic eruption causes resorption of primary canine – indicates lack of spaceLoss of only one primary canine can cause midline shift – need to maintain lateral incisor position with appliance orExtract contralateral canineLoss of mand. 1° canines causes incisors to tip lingually with loss of arch perimeterSpace analysis important – passive LLA or active LLA
55Ectopic Maxillary First Molar Prevalence2-6% (20-25% if cleft lip/palate)EtiologyCrowding / large crown / mesial eruptionMANAGEMENTOBSERVEActive TreatmentMay correct spontaneouslyRarely after age 8 yearsBrass wire or elastic separator – mild casesDistalizing appliances more serve casesExtract primary if pulpal involvement – space maintainer or regainer
56Age 8yr. O months Patient Y Zumwalt 495-5-27 Ectopic eruption of maxillary laterals (resorbing maxillary canines)Mandibular lateral resorbing canineAge 8yr. O months
64Early Loss of Primary Teeth Early loss of 2nd 1° molarMesial drift of first permanent molarGreater if no occlusal forces are on itEarly loss of 1° first molar or canineDistal drift of incisorsForce from active contraction of transseptal fibersPressure from the lips and cheekspgs –