Exam 1 Flashcards
Occlusion
Contact relationship between between maxillary and Mandibular teeth when jaw is fully closed and relationship between teeth in the same arch
When dentition is in occulusion the maxillary arch _____ the Mandibular arch ______&______
Overhangs
Horizontally
Vertically
Over jet
Horizontal overhang
Overbite
Vertical overhang or overlap between the 2 arches
Rest position of occlusal surfaces
Also “Interocclusal clearance” “freeway space”
Lips closed and jaw in nonfunctional position (occlusal surfaces not touching)
2-3mm of space
When is the only time teeth should touch?
Functional situations
Parafunctional habit
When teeth touch in nonfunctional situations
Ex: bruxism (grinding), clenching, finger sucking
Parafuncational habits are _____. Pt is usually ____, not ____ ______,etc.
as a clinician you should
Unconscientious
Anxious
Not paying attention
Make pt aware of habit
5 phases of Arch/dentition development
Phase 1- eruption of permanent 1st molars, man to max
Phase 2-eruption of permanent anterior teeth, c to l
Phase 3-eruption of permanent premolars (primary molars gone)
Important phase bc of leeway space
Phase 4-eruption of permanent canines and 2nd molars
*canine is final tooth to stabilize arch (completes arch/dentition)
*max. Canine last to be replaced @ 12 years old.
*Before arrival of canine, position transient (short time)
Phase 5-eruption of third molars
Chronological order of teeth coming in very important
Space maintainer recommended for prematurely extracted teeth
Permanent replacement can then find right space and erupt properly
Otherwise neighboring teeth will tilt to occupy the space and opposing teeth with super erupt
Mesial drift
Teeth have natural tendency to move mesially
What happens if tooth is extracted and not immediately replaced?
2 teeth around the space (anterior and posterior) will tilt to occupy this space
The opposing tooth will super erupt to try to occupy space
Disharmony for whole dentition
When examining pts mandible and natural functions, what are you observing?
Protrusion
Retrustion
(Forward and backward)
Lateral movements
Lateral occlusion
&
Working side v non working/balancing
Ask patient to move mandible to right and left
Only canines should touch cusp tip to cusp tip (contralaterly)
Side to which jaw has been moved
Opposite side of working
Protrusive occulusion
All 8 incisors touch at once
Centric relation
Position of mandible relative to maxilla
Mandible in most retruded position (not teeth to teeth)
Determined by maximum contraction of muscles of jaw —> during swallowing
Centric occlusion
Maximum contact between occluding surfaces of max and mand teeth
Forces on teeth that stabilize teeth in final position
Muscles surrounding teeth (both around and weak affect)
-facial expression, buccal, labial, tongue
Chronological order of teeth coming in and out
Primate spaces
-result of growth of bone between teeth
-mesial to maxillary canines and distal to Mandibular canines
Leeway space
-difference in size mesiodistally between primary molars and perm premolars
Lengthening of arch
Occlusion of permanent teeth is affected by
Occlusion of primary teeth
3 types of occlusion in primary teeth
Best to worst
Compares distal surfaces of second molars (maxillary and Mandibular)
- Mesial step
- Flush terminal plane
- Distal step
Mesial step
Distal surface of Primary Mandibular second molar MESIAL to maxillary second molar distal surface
Predicts permanent occlusion will be good
Flush terminal plane
Distal surfaces of both maxillary and Mandibular second molars are in an end to end relationship
50/50 probability that permanent occlusion will be good depending on other factors
(Primate space, leeway space, lining of jaw, restorations, extractions)
Distal step
Worst
Primary Mandibular second molar distal surface DISTAL to maxillary Second molar
Predicts permanent occlusion will be bad
Dentition
Natural teeth in jaw bone (primary and permanent)
Universal Tooth Numbering System
Primary A-T
Permanent 1-32
Dentition Periods
Primary:
6 months by eruption of Mandibular central incisors
Completed at 2 years by eruption of Mandibular Mandibular first molar
Mixed:
6 years by eruption of Mandibular first molar
12 years by exfoliation of maxillary canine
Permanent:
12 years by exfoliation of maxillary canine to death
Anatomy of tooth
Made predominantly of dentin covered by enamel on crown and cementum on root
Anatomical crown/root
What exists in nature
Crown=portion of tooth covered by enamel
Root=portion of tooth visible in oral cavity
Clinical crown/root
What we see
Crown=portion of tooth visible in oral cavity
Root=only seen when there’s recession
Malocclusion
Lack of overall ideal form in the dentition while in centric occlusion
Dental classification of malocclusion based on
Based on relationship of teeth
Usually canine and first molars
Angles classification system
Classified malocclusion based on canine and 1st molars
Class 1 malocclusion
Mesognathic
Mesial buccal cusp of maxillary first molar has to occlude in mesiobuccal groove of Mandibular first molar
Maxillary canine occludes between Mandibular canine and first premolar
Class II malocclusion
Mandible is retruded by width of premolar
Division I-anterior teeth protruded, palate narrow and high (retrognathic)
“Overbite”
Division II-maxillary central incisors upright and slightly retruded (mesognathic like class I)
Lateral incisor overlaps maxillary central incisors
Class III Malocclusion
Mandible protruded at least by width of premolar (prognathic facial profile)
Canine and mesial buccal groove move anteriorly
Curve or spee
Maxillary arch convex and mand arch concave
Sagittal view
Curve of Wilson
Seen in cornonal view
Maxillary convex
Mandibular concave
Contact area (specifically same arch)
Very important
Support tooth in position by 2 neighboring teeth and protects interdental gingiva
Protects food from plunging into space and causing destruction by infection
Primary teeth roots usually
Flare and diverge to accommodate the crown of permanent replacement
____ cusp of Mandibular teeth occlude with _____ cup of maxillary teeth to protect soft tissue (don’t bite cheek)
Buccal
Lingual
Maxillary central incisor
Largest central incisor
Mandibular central incisor
Smallest incisor
Incisor edge perpendicular to long axis of tooth
Contact area mesial and distal are same level
Distal and mesial Incisal angle are right angled
Lingual surface simple (ridges not too high, fossa not too deep)
Mandibular lateral incisor
Little bigger than central and more twisted in root
Maxillary central incisor and maxillary lateral incisor
Central is big
Lateral shores and narrower-More rounded coronal outline
Canines
Mandibular canine more narrow than max mesiodistally
Less developed Cingulum (softer features)
Narrower Labiolingually
More blunted cusp slightly taller
How to distinguish maxillary first premolar
Mesial crown conocavity that will give cross section kidney form
No concavity on distal
Lingual view of Mandibular first molar
Occlusal surface visible
Both marginal ridges visible
Mesilalingual groove really helps to distinguish
-starts in occlusal surface and goes into root
First molars have _ cusps
5
Second molars
4 cusps
Smaller than first and shorter occlusocervically
Roots closer together
Max second molar don’t have cusp of C
Mesial root has 2 canals
Maxillary first molar
Only tooth in jaw to diverge lingually
Maxillary molars
Wider facial lingually than MD
C of C with ML cusp
Largest lingual root
Second largest mesial buccal root
Smallest distal buccal root
Oblique ridge on maxillary molars
Triangular ridges of ML cusp and DB Cusp
Mandibular first molar groove pattern
Y shaped
2 buccal
2 lingual grooves
Mandibular second molar
1 buccal groove
1 lingual groove
Cross shaped groove pattern
Crowns of Mandibular inline ___
Crowns of maxillary incline ____
Lingually
Facially
Primary
Cervial ridge prominent on molars-buccal surface only
Lighter in color
Slender roots
Crown short in length compared to total root
Which cusps are functional?
Mandibular = buccal cusps
Maxillary = lingual cusps
Mesognathic
“Middle”, normal facial profile
Retrognatic
Rounded, exaggerated facial profile
Overbite
Prognathic
Concave facial profile
Mandible protruded
Primary dentition
6 months to 6 years
Full eruption around 2 years old, 2nd molars
Mixed
6-12 years
Starts as perm Mandibular first molar eruption, mand central incisor replaced
Ends exfoliation of max canine
