Dr. Tran Ngoc Quang Phi
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Backgrounds y Angle classification y Six keys Andrew y Crown form y Arch form y Bolton analysis y Golden proportion
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Angle Classification y Malposition → individual tooth y Buccal or labial, lingual, mesial, distal, torso (rotation), infra and supra. y Impacted y Malocclusion → anteroposterior relationships of permanent first molars and canines. y Canine relationship: y The upper canine fits distal to the lower canine y Molar relationship y Class I: normal relationships → mesial buccal cusp UFM≡mesial sulcus LFM. y Class II: distal buccal cusp UFM≡mesial sulcus LFM y Class III: buccal cusp USP≡mesial sulcus LFM 3
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Angle classification extension y Class II division 1: y Narrowing of the upper arch, lengthen and protruding UC. y Abnormal function of the lips, nasal obstruction, mouth breathing. y Class II division 1 subdivision: class I on one side. y Class II division 2: y Crownding, overlaping and lingual inclination UC y Normal nasal and lip function y Class II division 2 subdivision: class I on one side. y Class III subdivision: class I on one side. y Mild class II: between class I and class II y Mild class III: between class I and class III 5
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Class I Molar or Class I Canine?
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Four items that you "must complete" for successful orthodontic treatment 1. 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. 12
Six keys Andrew 1.
Molar relationship : y Class I Angle y Cusp‐embrasure relationship buccally y Cusp‐fossa relationship lingually
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Crown angulation: y All tooth crowns are angulated mesially (mesio‐distal tip)
3.
Crown inclination: y Incisors are inclined labially y Upper posterior teeth are inclined lingually, similarly from
the canine to the premolars; upper molars are inclined slightly more than the canine and the premolars. 13
Angulation and inclination
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y
Lower posterior teeth are inclined lingually, progressively from canine to molars
4. Rotations: y Rotations are not present 5. Spaces y Spaces are not present between teeth 6. Curve of Spee y The plane is either flat or slightly curve
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Curve of Spee Yes No
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Anterior Crown form Central 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 17
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Canine crown form
Relatively flat facial contour
Narrow and pointed incisally
Markedly curved facial contour
Wide and flattened incisally
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Arch form Square Ovoid Tapered
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y 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. y Any alteration of this position may result in instability in retention. y Relapse tendency after changing arch form (De La Cruz‐1995, Burke‐1998): inter‐canine width. y 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 y Determine the arch form at the start of treatment y Template ♦ y Computerized cast analysis @ y Arch wire stocked: y Round arch wire (NiTi and SS): ovoid only y .019/.025 (.018/.025 ) HANT: three shapes y y y
y
45% ovoid 45% square 10% tapered
.019/.025 (.018/.025 ) SS: ovoid only → 24
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Bolton analysis y Anterior Bolton analysis y Max 6: 40.0 – 54.5 (+0.5) y Mand 6: 30.9 – 42.1 (+0.4) y Overall Bolton analysis y Max 12: 85 – 110 (+1) y Mand 12: 77.6 – 100.4 (+ 0.9) y Ideal ratio → canine class I y Determine distance between hooks or loop y Bolton discrepancy → proper solution 27
Anterior Bolton analysis Full archBolton analysis
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Ideal ratio in Bolton analysis Maxillary 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
107
97.8
54.5
42.1
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Application? •Chose the T –loop arch wire •Adjust for the best fit occlusion
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Golden proportion
a + b a = = ϕ a b ϕ = 1 . 618
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→
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DIAGNOSIS y Collect data y Orthodontic questionaire y Clinical examination y X‐rays : POG and CEP y Models y Pictures y Cephalometric analysis y Model anlysis → Diagnosis: problem list
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Orthodontic Questionaire MEDICAL HISTORY y Under a physician's care at this time? Yes/No. Explain y Taking any medication at this time? Yes/No. Specify
Allergic to any medication? Yes/ No. Specify y Any other allergies? Yes/No. Specify y Need to be premedicated (antibiotics) for routine dental
procedures? _Yes _No. Specify and reason 37
Following diseases or conditions? (If yes, explain and date): y AIDS__ Bleeding disorder __ Anemia__ y Lung disease__ Cerebral palsy__ Heart condition__ y Arthritis__ Hepatitis__ Kidney disease__Rheumatic
fever___ Asthma__ Diabetes__ Epilepsy__ y Injury to face/head__ y Tonsil/adenoid surgery__ Previous surgery__ y Females: Is the patient pregnant? __ Yes __ No 38
DENTAL HISTORY y Date of last dental examination y Any injury to the face/teeth/gum? Explain and date. y Any previous orthodontic treatment/consultation? y Does the patient: y Grind his/her teeth at night? y Bite his/her fingernails? y Suck thumb, finger, pacifier, etc.?
y If yes, at what age was the habit discontinued? __years y Has another member of the family had orthodontic treatment? Whom? 39
Medical conditions to be considered in orthodontic treatment Medical 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 40
PATIENT'S ATTITUDE AND MOTIVATION y Is the patient aware of the problem? y Consultation here prompted by _________________ y Patient's interest in having treatment is: y __ Wants treatment ___ Willing if necessary __ Unwilling y If the patient’s teeth were to be changed, how would you
like them changed? _______________________________ y If any features of the face could be changed, what would
you like to see? ___________________________________ 41
GROWTH STATUS: (child patients only) y Height__________ cm
Weight _________kg
y Females: Has the patient started her menstruation? __ Yes __ No. If yes, at what age? ________ y Males: Voice changes? __ Yes __ No Facial hair growth? __ Yes __ No y Has the patient had any recent rapid growth? ___________ If so, how much?_______________
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Rational for Orthodontic questionaire y Chief complaints y Determine patient’s motivation, expectation y Medical and Dental history y Reveal the causes of problems y Relation between the patient’s conditions and orthodontic treatment y Growth and development y Timing of orthodontic treatment
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CLINICAL EXAMINATION y Esthetic analysis y Macro esthetics: facial proportion y Mini esthetics: tooth – lip relationships y Micro esthetics: dental appearance y Functional analysis y TMJ y Occlusion y Periodontal health y Bad habit 44
Macro esthetics: facial proportion y General view y Dolicofacial, brachyfacial, mesiofacial → y Frontal view y Vertical y y y
y
Horizontal y
y
Proportion Chin height Lower face height 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: y Dolicofacial pattern y Vertical maxillary excess (VME) ♦ y High lip line: anterior teeth display too much y Gummy smile y Lip length: normal y ≠ Short lip ♦ y Excesssive chin height ♦ B. Decrease face height y Brachyfacial pattern y Vertical maxillary deficiency y Mandibular defienciency ♦ y Short chin height ♦ 48
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 49
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. 50
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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Pre‐orthodontic Post‐ orthodontic@
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Short lip: @ Philtrum height < commisure height Inverted lip
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Asymmetry y Upper midline asymmetry y Orthodontist : < 2mm y Dentist : 2 – 4mm y Non‐professional person: >4mm y Lower midline asymmetry y Cause y Upper : missing tooth, impacted tooth, crowding… y Lower: causes as upper arch, esp: TMJ y Always the tough cases 59
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y Profil view y Proportion y Convex, straight, concave y Straight: anterior divergence, posterior divergence y Mandibular plane angle y Lower face y y y
Maxillary projection Mandibular projection Chin projection
y Lip y Lip posture and incisor prominence y Lip fullness y Labiomental sulcus y Throat form y Chin – throat angle y Throat length y Submental contour 61
Profil view
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Black pattern
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Convex treatment? y 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. y Move the chin forward to reduce feeling convex y Lefort I + BSSO for comprehensive treatment
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Mini esthetics: Tooth – lip relationship y y y y y
Philtrum height Commisure height Interlabial gap Incisal display at rest Smile analysis y y y y y y y
Emotional smile and social smile Incisal display on smile Gingival display Smile arc Buccal coridor width Arch form Transverse cant 68
Vertical measurements
A: Philtrum height
A: Incisal display on smile
B: Commisure height C: Interlabial gap
B: Crown height and width C: Gingival display
D: Incisal display at rest
D: Smile arc 69
Emotional smile and social smile
Major zygomaticus muscle
Risorius muscle
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Smile arc y The 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 smile y y y y
Crown lengthening Orthodontic treatment Lefort I Osteotomy Plastic surgery
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Micro esthetics: gingival and dental appearance y y y y y
Tooth proportion: crown height and width Width relationship and golden proportion Gingival height , shape and contour Connectors and embrasures Tooth shade and color
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Crown height and width y The width of central upper incisor should be about 80% of it’s height. y 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 contour Gingival 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. 77
Connectors and embrasures Connector # 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 incisal and gingival to the connector. Gingival embrasures are filled by interdental papillae. Short interdental papillae → black triangle. Tapered crown form → black triangle 78
Clinical considerations y y y y y
Open bite Tongue thrust Functional shift Missing tooth Lower Anterior Tissue Thickness
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Open bite Principle: Teeth erupt until they hit something. y 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. y 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. 80
Tongue thrust y A test for anterior tongue thrust is to: y Take a small sip of water. y Close the teeth together with the lips open. y Swallow. y A patient with an anterior tongue thrust will either: y Not be able to keep his/her lips open. y Will tilt his/her head back for gravity to keep the water from squirting forward. y Will squirt the water between the teeth forward onto their shirt (child patient). y A good exercise to give a patient with an anterior tongue thrust
(especially in the presence of open bite or excess anterior overjet) is: y Take a small sip of water. y Close the teeth together with the lips open. y 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 Shift y Forward functional shift y Lateral functional shift y Unilateral crossbite y Dental midlines not centered. y The asymmetric face from the frontal view.
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Missing Tooth y This 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. y 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 Thickness Principle: The lower arch is considered the limiting arch in edgewise diagnosis. y To align crowded teeth, advancement (forward movement) of the teeth will inevitably occur. y If the advancement of the lower incisors is significant, then a periodontal defect (stripping of gingival tissue is the most common) can occur. y 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. 85
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Cephalometric analysis: lanmarks
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Planes
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Growth direction
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SNB Mandible is protrusive if > 83 Mandible 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
260 220
Closed 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 +4.50 Class III tendency: +0.50 to +1.50
Wits
A, B ⊥ Occlusal plane
0 mm
Class I : ‐1 to +2 98
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Cephalometric analysis – Dental Description
Measurement
Mean
Range
1 Interincisal Angle
1
to
1
1300
Best finish 125 0 – 1300
Lower Incisal Inclination
1
to MP
920
Retroclined 890 – 980 Proclined
Lower Incisal Protrusion
1
to NB
+4mm
Retruded +1 to +6 Protruded
Lower Incisal Protrusion
1
to APo
+2mm
Retruded 0 to +4 Protruded
Upper Incisal Inclination
1
to SN
1030
Retroclined 990 – 1060 Proclined
Upper Incisal Protrusion
1
to APo
5mm
Retruded +2 to +7 Protruded
Upper Incisal Protrusion
1
to A vertical
4mm
Retruded +2 to +6 Protruded
(to FH)
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Cast analysis
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Cast analysis by software
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Advantages of computerized analysis y Accurate y Easy y More information: y Arch form y Loop distance (Bolton analysis) y Determine asymmetric Arch y Space analysis y Rotation y Prediction 110
DETERMINE THE PROBLEMS y Kind of problems: y Dental problems y Skeletal problems y Facial problems y Occlusal problems y TMJ problems y Periodontal problems y Causative factors y Degree of problems 111
Ackerman and Proffit diagram y y y y y
Aligment (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) y Sagittovertical deviation (combine Angle class and deep bite or open bite) y Verticotransverse deviation (combine cross bite and deep bite or open bite) y Transsagittovertical deviation (combine of problems in three planes of space) 112
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DENTAL PROBLEMS y y y y
Intra‐arch problems Inter‐arch problems Causative factors Degree of the dental problems
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Intra‐arch problems y Position : y Protrusion or retrusion of incisors y Malposition y Impaction y Rotation y Angulation y Inclination: y Procline or recline y Spaces: y Spacing or crowding y Curve of Spee 115
Inter‐arch problems y Molar relationship y Class I, II, III y Canine relationship y Class I, II, III y Vertical relationship: y Overbite, deep bite, open bite y Horizontal relationship: y Overjet, end‐to‐end, anterior crossbite. y Posterior crossbite y Upper and lower incisor angulation y Inter‐arch discrepancy y Midline relationship: y Midline asymmetry 116
Causative factors y Spacing y Large jaw y Small teeth y Missing teeth y Lateral over‐expansion of arches or forward proclination of anterior teeth. y Crowding y Small or constricted arches y Large teeth y Retroclination y Mesial drift of posterior teeth 117
y Openbite y Bad habit: thumb sucking, finger sucking or pacifier using, tongue thrush, lip habit. y High tongue posture y Airway obstruction: allergies, enlarged tonsils, adenoids, septum problem… y Intracapsular TMJ problems y Skeletal growth abnormalities
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Diagnosis of Impacted Teeth y Impacted Teeth : not erupted for 2 years following the normal eruption age. y The eruption path is blocked, or if the eruption stops after the tooth strays to a position labial or lingual to another tooth. y The most common impaction: the upper canine. y DIAGNOSIS OF AN UPPER IMPACTED CANINE y Panoramic x‐ray: Any overlap of the canine crown with the lateral incisor roots → impaction?. y Palatal or labial? y Palpate the labial tissue y Occlusal x‐ray 119
Crowding and impacted tooth y The "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. y Evaluate the root formation to determine eruption potential: incomplete root formation → eruption potential. y 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 tooth y y y y y y
Position: labial (good) or palatal Angulation: the more vertical the more success Space available: enough? The path to the correct position? The age: best under 25 The risk: Ankylosis y Damage the adjacent teeth y
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Degree of problems: Diagnostic Parameters Canine and molar relationships: RM, RC, LM, LC Angle classification Overbite Overjet Stage of dental development Presence of crossbite: with or without functional shift 7. Space analysis 8. POG interpretation 9. CEP interpretation 1. 2. 3. 4. 5. 6.
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1.
Canine and molar relationships: RM, RC, LM, LC a. b. c. d.
Class I Class II* Class III* 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.
Overbite a. b. c. d. e.
Normal (5 % ‐ 20%) Moderate deep bite (20% ‐ 50%) Severe deep bite ( > 50%)* Edge to edge Anterior open bite
4. Overjet a. Normal (1 – 3mm) b. Excessive ( > 3mm)* c. Edge to edge d. Underjet (negative overjet)
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5.
Stage of dental development a. b. c. d.
Deciduous dentition Early Mixed dentition Late Mixed dentition Permanent dentition
6. Presence of cross bite: with or without functional shift a. None b. Anterior c. Posterior d. Both
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7.
Space analysis a. b. c. d. e.
Adequate arch length ( +1 to ‐1mm) Mild crowding (‐2 to ‐3mm) Moderate crowding (‐4 to ‐6mm) or Severe (> ‐6mm) Mild spacing (1 – 3mm) Moderate spacing (4 to 6mm) or Severe (> 6mm)
8. POG interpretation a. Normal b. Abnormal: missing, supernumerary, ectopic, impacted tooth) 9. CEP interpretation a. Normal b. Beyond the normal range: 1 SD c. Beyond the normal range: 2 SD d. Beyond the normal range: 3 SD 126