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Dr. Tran Ngoc Quang Phi
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BackgroundsAngle classificationSix keys AndrewCrown formArch form Bolton analysisGolden proportion
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Angle ClassificationMalposition→ individual tooth
Buccal or labial, lingual, mesial, distal, torso (rotation), infra and supra. Impacted
Malocclusion → anteroposterior relationships of permanent first molars and canines. Canine relationship:
The upper canine fits distal to the lower canineMolar relationship
Class I: normal relationships →mesial buccal cusp UFM≡mesial sulcus LFM.Class II: distal buccal cusp UFM≡mesial sulcus LFMClass III: buccal cusp USP≡mesial sulcus LFM
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Angle classification extensionClass II division 1:
Narrowing of the upper arch, lengthen and protruding UC. Abnormal function of the lips, nasal obstruction, mouth breathing.
Class II division 1 subdivision: class I on one side. Class II division 2:
Crownding, overlaping and lingual inclination UCNormal nasal and lip function
Class II division 2 subdivision: class I on one side. Class III subdivision: class I on one side. Mild class II: between class I and class IIMild class III: between class I and class III
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Class I Molar or Class I Canine?
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♦
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♦♦
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Four items that you "must complete" for successful orthodontic treatment1. The teeth must be straight at the end of treatment. 2. There must not be any spaces between the front
teeth. 3. There must not be any overjet (the patient refers to
overjet as "overbite"). 4. The teeth must (generally) bite together at the end
of treatment. It is OK to have a bicuspid out of occlusion, but the teeth must not be open molar to molar.
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Six keys Andrew1. Molar relationship :
Class I AngleCusp‐embrasure relationship buccallyCusp‐fossa relationship lingually
2. Crown angulation: All tooth crowns are angulated mesially (mesio‐distal tip)
3. Crown inclination: Incisors are inclined labiallyUpper posterior teeth are inclined lingually, similarly from the canine to the premolars; upper molars are inclined slightly more than the canine and the premolars.
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Angulation and inclination
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Lower posterior teeth are inclined lingually, progressively from canine to molars
4. Rotations:Rotations are not present
5. SpacesSpaces are not present between teeth
6. Curve of SpeeThe plane is either flat or slightly curve
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Curve of SpeeYes No
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Anterior Crown formCentral incisor crown form:•Triangular‐shaped incisors: need to be reshaped to avoid one‐point contact (→ black triangle and unstable)•Rectangular‐shaped incisors: good esthetics•Barrel‐shaped incisors: do not provide ideal esthetics
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Canine crown form
Markedly curved facial contour
Narrow and pointed incisally Wide and flattened incisally
Relatively flat facial contour
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Arch form
Square Ovoid Tapered
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The original arch form is considered the most stable position since this is the "in balance" position of the teeth and surrounding muscles: the neutral zone.Any alteration of this position may result in instability in retention.Relapse tendency after changing arch form (De La Cruz‐1995, Burke‐1998): inter‐canine width. Expansion the lower arch form: 10%.
Tapered Ovoid Square
Japaneses 12% 42% 46%
Caucasians 44% 38% 18%
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Systemized management of arch form Determine the arch form at the start of treatment
Template ♦Computerized cast analysis @
Arch wire stocked:Round arch wire (NiTi and SS): ovoid only.019/.025 (.018/.025 ) HANT: three shapes
45% ovoid 45% square10% tapered
.019/.025 (.018/.025 ) SS: ovoid only →
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♦
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Bolton analysisAnterior Bolton analysis
Max 6: 40.0 – 54.5 (+0.5)Mand 6: 30.9 – 42.1 (+0.4)
Overall Bolton analysisMax 12: 85 – 110 (+1)Mand 12: 77.6 – 100.4 (+ 0.9)
Ideal ratio → canine class IDetermine distance between hooks or loop Bolton discrepancy → proper solution
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Anterior Bolton analysis Full archBolton analysis
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Ideal ratio in Bolton analysisMaxillary 6 Mandibular 6 Maxillary 12 Mandibular 12
40.0 30.9 85 77.6
40.5 31.3 86 78.5
41.0 31.7 88 80.3
41.5 32.0 89 81.3
90 82.1
48.0 37.1 91 83.1
48.5 37.4 96 87.6
97 88.6
51.5 39.8 103 94.0
52.0 40.1 104 95.0
106 96.8
54.5 42.1 107 97.8
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Application? •Chose the T –loop arch wire •Adjust for the best fit occlusion
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Golden proportion
618.1=
==+
ϕ
ϕba
aba
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→
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DIAGNOSIS Collect data
Orthodontic questionaireClinical examinationX‐rays : POG and CEPModelsPictures
Cephalometric analysisModel anlysis
→ Diagnosis: problem list
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Orthodontic QuestionaireMEDICAL HISTORY
Under a physician's care at this time? Yes/No. Explain
Taking any medication at this time? Yes/No. Specify
Allergic to any medication? Yes/ No. Specify
Any other allergies? Yes/No. Specify
Need to be premedicated (antibiotics) for routine dental
procedures? _Yes _No. Specify and reason
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Following diseases or conditions? (If yes, explain and date):
AIDS__ Bleeding disorder __ Anemia__
Lung disease__ Cerebral palsy__ Heart condition__
Arthritis__ Hepatitis__ Kidney disease__Rheumatic
fever___ Asthma__ Diabetes__ Epilepsy__
Injury to face/head__
Tonsil/adenoid surgery__ Previous surgery__
Females: Is the patient pregnant? __ Yes __ No
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DENTAL HISTORY
Date of last dental examination
Any injury to the face/teeth/gum? Explain and date.
Any previous orthodontic treatment/consultation?
Does the patient:Grind his/her teeth at night? Bite his/her fingernails? Suck thumb, finger, pacifier, etc.?
If yes, at what age was the habit discontinued? __years
Has another member of the family had orthodontic treatment? Whom?
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Medical conditions to be considered in orthodontic treatmentMedical condition Implications Action
Asthma Root resorption Monitor every 6 mo for evidence of EARR
Allergies Allergic reaction Determine materials causing allergy
Coagulation disorders Bleeding risk Extraction?
Diabetes Periodontal disease Monitor adequate control of diabetes
Epilepsy, High blood pressure
Gingival hypertrophy
Plaque control, gingivectomy if necessary
Heart valve conditions Endocarditis Premedication when extraction, fitting bands
Rheumatoid arthritis TMJ degeneration Monitor TMJ
Xerostomia Caries Fluoride supplement
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PATIENT'S ATTITUDE AND MOTIVATION
Is the patient aware of the problem?
Consultation here prompted by _________________
Patient's interest in having treatment is:
__ Wants treatment ___ Willing if necessary __ Unwilling
If the patient’s teeth were to be changed, how would you
like them changed? _______________________________
If any features of the face could be changed, what would
you like to see? ___________________________________
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GROWTH STATUS: (child patients only)
Height__________ cm Weight _________kg
Females: Has the patient started her menstruation? __ Yes __ No. If yes, at what age? ________
Males: Voice changes? __ Yes __ No Facial hair growth? __ Yes __ No
Has the patient had any recent rapid growth? ___________ If so, how much?_______________
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Rational for Orthodontic questionaireChief complaints
Determine patient’s motivation, expectationMedical and Dental history
Reveal the causes of problemsRelation between the patient’s conditions and orthodontic treatment
Growth and developmentTiming of orthodontic treatment
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CLINICAL EXAMINATIONEsthetic analysis
Macro esthetics: facial proportionMini esthetics: tooth – lip relationshipsMicro esthetics: dental appearance
Functional analysisTMJOcclusion Periodontal healthBad habit
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Macro esthetics: facial proportion General view
Dolicofacial, brachyfacial, mesiofacial →Frontal view
Vertical ProportionChin height Lower face height
Horizontal Proportion: rule of fifth
Midline asymmetry
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Vertical proportion
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Horizontal proportion
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The lower third @A. Increase face height:
Dolicofacial patternVertical maxillary excess (VME) ♦High lip line: anterior teeth display too much Gummy smileLip length: normal ≠ Short lip ♦Excesssive chin height ♦
B. Decrease face heightBrachyfacial patternVertical maxillary deficiencyMandibular defienciency ♦Short chin height ♦
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Dolicofacial
•Long and thin faces. Weak muscles of mastication that are not strong enough to hold the teeth together during orthodontic treatment. •Non extraction treatment of these cases may result in bite opening during the treatment. •When extraction, space closes quickly.Be careful when treating a protrusion case
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Mesiofacial
•Mesiofacial is not long and thin facial features, and not short and square facial features. •In these cases you can extract and the extraction spaces will close "normally". •You can treat these case types non extraction and the teeth will remain in occlusion during treatment.
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Brachyfacial
•Short, square faces with very strong muscles of mastication.•Short clinical crowns with some excess enamel wear on the occlusal surface of the teeth. •In these cases, if you extract, then the extraction spaces will close slowly.
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♦
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♦
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Pre‐orthodontic Post‐orthodontic@
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@@
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Short lip: @Philtrum height < commisure height Inverted lip
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AsymmetryUpper midline asymmetry
Orthodontist : < 2mmDentist : 2 – 4mmNon‐professional person: >4mm
Lower midline asymmetryCause
Upper : missing tooth, impacted tooth, crowding…Lower: causes as upper arch, esp: TMJ
Always the tough cases
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Profil viewProportion Convex, straight, concaveStraight: anterior divergence, posterior divergenceMandibular plane angleLower face
Maxillary projectionMandibular projectionChin projection
Lip Lip posture and incisor prominenceLip fullnessLabiomental sulcus
Throat form Chin – throat angle Throat lengthSubmental contour
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Profil view
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Black pattern
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Convex treatment?Be careful not to set the patient's expectations too high for reducing a convex profile: it takes 2‐3mm of tooth retraction to result in 1mm of lip retraction.Move the chin forward to reduce feeling convexLefort I + BSSO for comprehensive treatment
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Mini esthetics: Tooth – lip relationshipPhiltrum heightCommisure heightInterlabial gapIncisal display at restSmile analysis
Emotional smile and social smileIncisal display on smileGingival display Smile arcBuccal coridor widthArch formTransverse cant
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Vertical measurements
A: Philtrum height
B: Commisure height
C: Interlabial gap
D: Incisal display at rest
A: Incisal display on smile
D: Smile arc
C: Gingival display B: Crown height and width
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Emotional smile and social smile
Major zygomaticus muscle Risorius muscle
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Smile arcThe contour of the incisal edges of the maxillary anterior teeth relative to the curvature of the lower lip during a social smile
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Transverse cant
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Gummy smileCrown lengtheningOrthodontic treatmentLefort I OsteotomyPlastic surgery
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Micro esthetics: gingival and dental appearance
Tooth proportion: crown height and widthWidth relationship and golden proportionGingival height , shape and contourConnectors and embrasuresTooth shade and color
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Crown height and widthThe width of central upper incisor should be about 80% of it’s height.The disproportion should be done before orthodontic treatment is completed.
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Width relationship and golden proportion
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Gingival shape and contourGingival shape of upper central incisors and canines is more elliptical.Gingival shape of upper lateral incisors and mandibular incisors is a symmetric half‐oval or half‐circular one.The gingival zenith of central and canine is located distal to the longitudinal axis. The gingival zenith of lateral incisors coincides with the longitudinal axis.
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Connectors and embrasuresConnector # contact point area:Include the areas above and below the contact point.Greatest between the central incisors and diminish from the centrals to the posteriors. Embrasures: triangular spaces incisaland gingival to the connector. Gingival embrasures are filled by interdental papillae. Short interdental papillae → black triangle. Tapered crown form → black triangle
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Clinical considerationsOpen biteTongue thrustFunctional shiftMissing tooth Lower Anterior Tissue Thickness
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Open bite Principle: Teeth erupt until they hit something.
Open bite: the lower incisor does not contact the upper incisor. There are obvious open bite cases where the teeth are separated in the anterior. In some class II cases where the amount of overlap of the upper incisor vs. the lower incisor is normal (1/3 coverage), but the lower incisor does not contact the tooth nor the palate.
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Tongue thrustA test for anterior tongue thrust is to:
Take a small sip of water. Close the teeth together with the lips open. Swallow.
A patient with an anterior tongue thrust will either: Not be able to keep his/her lips open. Will tilt his/her head back for gravity to keep the water from squirting forward. Will squirt the water between the teeth forward onto their shirt (child patient).
A good exercise to give a patient with an anterior tongue thrust(especially in the presence of open bite or excess anterior overjet) is:
Take a small sip of water. Close the teeth together with the lips open. Swallow with the throat muscles. Tell the patient to hold their hand on their throat as they learn this exercise to feel the muscle contraction.
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Functional ShiftForward functional shiftLateral functional shift
Unilateral crossbiteDental midlines not centered.The asymmetric face from the frontal view.
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Missing ToothThis seems very obvious, but in many cases where a tooth has been lost, the space has closed spontaneously by dental drifting. It is very easy to not notice a missing tooth in a dental arch when doing your examination. Be certain that you count 4 incisors, 2 canines, 4 bicuspids, etc. in each arch, before checking "none."
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Lower Anterior Tissue ThicknessPrinciple: The lower arch is considered the limiting arch in edgewise diagnosis. To align crowded teeth, advancement (forward movement) of the teeth will inevitably occur. If the advancement of the lower incisors is significant, then a periodontal defect (stripping of gingival tissue is the most common) can occur. Advancement of incisors with "thin tissue" has more risk than advancement with "thick tissue" labial to the lower incisors. As the teeth advance, the tissue will become thinner.
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Cephalometric analysis: lanmarks
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Planes
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Growth direction
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SNBMandible is protrusive if > 83Mandible is average if 76 – 82 Mandible is retrusive if <75
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Cephalometric analysis – Skeletal Description Measurement Mean Range
Pal. plane to Md. Plane: Skeletal Open/closed
ANS‐PNS to Md. plane 280 Closed 240 – 330 Open
Md. Plane angle: Skeletal Open/closed FH – MA: Child Adult
260
220Closed 200 – 300 Open
240 – 330
Y – Axis Vert/Hor Growth SGN ‐ FH 590 Hor. 570 – 620 Vertical
Maxilla to Cranium N ⊥ A +1mm Retruded ‐1 to +3 Protruded
Maxilla to Cranium SNA 820 Retruded 760 – 830 Protruded
Mandible to Cranium N ⊥ Po : Child Adult
‐7mm‐1mm
Retruded ‐10 to ‐4 Protruded‐4 to ‐1
Mandible to Cranium SNB 790 Retruded 750 – 830 Protruded
Maxilla to Mandible ANB 20 Class I : + 20 to +4.50Class III tendency: +0.50 to +1.50
Wits A, B ⊥ Occlusal plane 0 mm Class I : ‐1 to +2
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Cephalometric analysis –Dental
Description Measurement Mean Range
Interincisal Angle to 1300 Best finish 125 0 – 1300
Lower Incisal Inclination to MP 920 Retroclined 890 – 980 Proclined
Lower Incisal Protrusion to NB +4mm Retruded +1 to +6 Protruded
Lower Incisal Protrusion to APo +2mm Retruded 0 to +4 Protruded
Upper Incisal Inclination to SN 1030 Retroclined 990 – 1060 Proclined
Upper Incisal Protrusion to APo 5mm Retruded +2 to +7 Protruded
Upper Incisal Protrusion to A vertical
(to FH)
4mm Retruded +2 to +6 Protruded
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1
1
1
1
1
1
1
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Cast analysis
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Cast analysis by software
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Advantages of computerized analysisAccurateEasyMore information:
Arch form Loop distance (Bolton analysis)Determine asymmetric Arch Space analysisRotation Prediction
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DETERMINE THE PROBLEMSKind of problems:
Dental problemsSkeletal problemsFacial problemsOcclusal problemsTMJ problemsPeriodontal problems
Causative factorsDegree of problems
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Ackerman and Proffit diagramAligment (spacing and crowding)Profile (convex, straight, concave)Sagittal deviation (Angle class)Vertical deviation (deep bite, open bite)Transsagittal deviation (combine Angle class and cross bite)Sagittovertical deviation (combine Angle class and deep bite or open bite)Verticotransverse deviation (combine cross bite and deep bite or open bite) Transsagittovertical deviation (combine of problems in three planes of space)
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DENTAL PROBLEMSIntra‐arch problemsInter‐arch problemsCausative factorsDegree of the dental problems
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Intra‐arch problemsPosition :
Protrusion or retrusion of incisorsMalpositionImpaction
RotationAngulationInclination:
Procline or reclineSpaces:
Spacing or crowdingCurve of Spee
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Inter‐arch problemsMolar relationship
Class I, II, IIICanine relationship
Class I, II, IIIVertical relationship:
Overbite, deep bite, open bite Horizontal relationship:
Overjet, end‐to‐end, anterior crossbite.Posterior crossbite
Upper and lower incisor angulationInter‐arch discrepancyMidline relationship:
Midline asymmetry
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Causative factorsSpacing
Large jawSmall teethMissing teethLateral over‐expansion of arches or forward proclination of anterior teeth.
CrowdingSmall or constricted archesLarge teethRetroclinationMesial drift of posterior teeth
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OpenbiteBad habit: thumb sucking, finger sucking or pacifier using, tongue thrush, lip habit.High tongue postureAirway obstruction: allergies, enlarged tonsils, adenoids, septum problem…Intracapsular TMJ problemsSkeletal growth abnormalities
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Diagnosis of Impacted TeethImpacted Teeth : not erupted for 2 years following the normal eruption age.The eruption path is blocked, or if the eruption stops after the tooth strays to a position labial or lingual to another tooth. The most common impaction: the upper canine. DIAGNOSIS OF AN UPPER IMPACTED CANINEPanoramic x‐ray: Any overlap of the canine crown with the lateral incisor roots → impaction?. Palatal or labial?
Palpate the labial tissueOcclusal x‐ray
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Crowding and impacted toothThe "impacted tooth" may be BLOCKED OUT of the arch because of crowding: in a good position but cannot erupt due to a lack of space →blocked out. Evaluate the root formation to determine eruption potential: incomplete root formation → eruption potential. Tx: space is made with open coils or extraction and a deadline # 12 months is set to wait for its eruption.
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Consideration in impacted toothPosition: labial (good) or palatalAngulation: the more vertical the more successSpace available: enough?The path to the correct position?The age: best under 25The risk:
AnkylosisDamage the adjacent teeth
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Degree of problems: Diagnostic Parameters
1. Canine and molar relationships: RM, RC, LM, LC2. Angle classification 3. Overbite4. Overjet5. Stage of dental development6. Presence of crossbite: with or without functional
shift7. Space analysis8. POG interpretation9. CEP interpretation
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1. Canine and molar relationships: RM, RC, LM, LCa. Class Ib. Class II*c. Class III*d. Not fully erupted
2. Angle classification a. Class I malocclusion b. Class II malocclusion, division 1, 2 and subdivision*c. Class III malocclusion, subdivision*
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3. Overbitea. Normal (5 % ‐ 20%)b. Moderate deep bite (20% ‐ 50%)c. Severe deep bite ( > 50%)*d. Edge to edge e. Anterior open bite
4. Overjeta. Normal (1 – 3mm)b. Excessive ( > 3mm)*c. Edge to edge d. Underjet (negative overjet)
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5. Stage of dental developmenta. Deciduous dentition b. Early Mixed dentitionc. Late Mixed dentitiond. Permanent dentition
6. Presence of cross bite: with or without functional shifta. None b. Anterior c. Posteriord. Both
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7. Space analysisa. Adequate arch length ( +1 to ‐1mm)b. Mild crowding (‐2 to ‐3mm)c. Moderate crowding (‐4 to ‐6mm) or Severe (> ‐6mm)d. Mild spacing (1 – 3mm)e. Moderate spacing (4 to 6mm) or Severe (> 6mm)
8. POG interpretationa. Normal b. Abnormal: missing, supernumerary, ectopic, impacted
tooth) 9. CEP interpretation
a. Normal b. Beyond the normal range: 1 SDc. Beyond the normal range: 2 SDd. Beyond the normal range: 3 SD