Test 2 Flashcards
What is the normal clinical arch shape in primary occlusion?
Very little discrepancy and described as ovoid
What is generalized normal spacing between all decidous teeth?
Physiological spacing
What is the exaggerated spacing mesial to the maxillary primary canines and distal to the mandibular primary canines?
Primate spacing
What is the normal order of eruption of primary teeth?
1s (lower, upper)
2s (upper, lower)
4s (upper, lower)
3s (upper, lower)
5s (lower, upper)
Which often erupts ealier, girls’ or boys’ dentition?
Girls
What is considered normal for the variation of eruption?
6 months
Arches must be wide enough at birth to accodomodate?
Centrals and laterals
What is this?
Primate spacing
What is this spacing?
Physiological spacing
The combined mesiodistal widths of deciduous canine, first and second molars is more than that of the combined mesiodistal width of permanent canine, first and second premolar. What is the difference between the two called?
Leeway Space
How do you classify the occlusion using the primary second molar?
Look at the distal aspect of the primary second molars
What type of terminal plane has the distal of the primary second molars aligned?
Flush or parallel terminal plane
What is the occurance rate of a flush or parallel terminal plane?
70%
What type of terminal plane has the mandibular second molars mesial to the maxillary second molars?
Mesial step
What is the occurance rate of the mesial step terminal plane?
14%
What permanent dentition occlusion is mesial step similar to?
Class I
What type of terminal plane has the mandibular second molars distal to the maxillary second molars?
Distal step
What is the occurance rate of the distal step terminal plane?
10%
What terminal plane is this?
Distal step
What terminal plane is this?
Parallel or flush
What type of terminal plane is this?
Mesial step
What type of terminal plane is this?
Mesial step
What is the straight or more vertical positioning of the primary teeth, very little to no inclination, of the crown of the incisors to the root position? (Straight up and down)
Axial inclination
What are discrepancies between tooth size and jaw size called?
Size-arch length discrepancy
What is defined as the length of the arch from the mesial surface of one 1st permanent molar aruond the contact points of the teeth to the same point on the opposite permanent 1st molar?
Arch length
Normal generalized primary spacing, physiological spacing, is also known as
Type 1 spacing
The mandibular deciduous molars are larger than the maxillary deciduous molars; therefore, the leeway space is
Slightly greater in the lower arch than in the upper arch
The transition from the mixed to adult dentition causes a decrease in the arch length due to
The forward movement of the permanent 1st molars into the leeway space
In a paralell terminal plane, the lower primate space closes after?
The eruption of the 1st molars
What is the terminal flush or parallel plane with type 1 spacing becoming a class 1 occlusion due to the loss of primate spacing known as?
Early mesial shift
When does an early mesial shift occur?
Age 6.5 - 7
What does primate spacing look like in a parallel terminal plane with type 2 spacing?
No primate space
What is a parallel terminal plane with type 2 spacing becoming a Class I occlusion due to the loss of the primary molars known as?
Late mesial shift
True or False: leeway space is used in a late mesial shift after the primary molars are shed around 10 years of age.
False. Leeway space is used in a late mesial shift after the primary molars are shed around 12 years of age.
What occlusions can a distal step become?
Class II
What occlusions can a flush/parallel terminal plane become?
Class I
Class II
End/end (edge/edge)
What occlusions can a mesial step become?
Class I
Class III
What must occur to accommodate the larger permanent incisors?
Growth at the midpalatine suture of the maxilla and the symphasis of the mandible
Why does normal suture growth not keep pace with the incisor liability?
The midpalatine suture stops growing around age 9 while the symphasis of the manible closes at age 1
What is the most important means for a harmonious transition between the anterior mixed and permanent dentition?
Interdental spacing
What four major factors influence the transitional dentition?
Forward growth of the maxilla
Maxillary leeway space
Forward growth of the mandible
Mandibular leeway space
What is forward growth of the maxilla important in the transitional dentition?
To provide anterior spacing
Why is maxillary leeway space important in the transitional dentition?
Allows for shift of the maxillary 1st molar in a Class I occlusion
Why is forward growth of the mandible important in the transitional dentition?
To catch up with the maxilla
What is the mandibular leeway space important in the transitional dentition?
Allows for the shift of the mandibular first molars into a Class I occlusion
What is the most important factor influencing the transitional dentition?
Skeletal growth
What are the three eruption patterns for anterior teeth?
- Primaries resorb from lingual to apical. Removal may be needed if the permanent teeth erupt prior to exfoliation. Teeth may appear crowded but will move labially into position after primaries exfoliate.
- Lower anterior teeth are spaced and resorb at the apical, permanent incisors erupt directly into the path of exfoliated teeth and in good alignment. Primate space is forced distally and labially. Max cuspids will adjust distally to maintain normal cuspal interdigitation
- Permanent incisors may erupt into crowded arch Disharmony between tooth and arch may manifest in many ways depending on the crowding involved.
What are these?
Possible eruption patterns of the anterior permanent teeth
11/21 erupt at age 6.5 - 7.5 and are separated by
2-3mm and often a 1mm+ diastema
What is the resulting inclination of 11/21 erupting with a 2-3mm space with a diastema?
Distal inclination
How will 21/11 take a more vertical position during devlelopment?
The eruption of the laterals
What will close the diastema during development?
Eruption of the cuspids
What is the ugly duckling stage?
When the centrals are straight, the laterals are tipped distally and the canines erupt tipped mesially, which eventually results in all anterior teeth being straight
A diastema is due to
Frenum involvement
What are the possible factors for abnormal midline diastemas?
Genetic
Congential absence
Supernumerary teeth
Blocked out laterals/canines
Small teeth in a large jaw
Midline cysts
Abnormal frenal attachment
How to detect frenal involvement?
If the frenal area blanches when the lip is lifted it often indicates involvement or a radiograph of interdental boney septum
What is the recommendation for a diastema?
Attempt ortho first for at least three weeks to close it with natural resorption. If that is not successful, consider frenectomy
Performing a frenectomy too soon may lead to
Scar tissue which may impede closing any remaining space
What are the more popular methods of frenectomies?
Electrosurgery
Laser surgery
What is the functional relationship between the masticatory system, including the teeth, supporting tissues, neuromuscular system, temporomandibular joints and the craniofacial skeleton?
Occlusion
What is any deviation from a physiologically acceptable contact of opposing teeth?
Malocclusion
What is the relationship of the mandible to the maxilla when the teeth are in maximal occlusal contact?
Centric occlusion
The maxillary buccal cusps/incisal edges are normally positioned in what relation to the mandibular teeth?
Outside of the mandibular teeth
What are the characteristics of the ideal bite?
- All biting forces directed through the long axis of the tooth
- Class I molar relationship
- No spacing, crowding, rotations, or versions
- Max buccal cusps are outside mand teeth
- Max posterior lingual cusps fit within mand posterior central fossas
What is the curvature of the mandibular occlusal plane measured from cusp of canine posteriorly along cusps on mandible?
Curve of Spee
How should the Curve of Spee be in a Class I ideal bite?
Allow for the normal functional protrusive movement of the mandible
What is the curvature in a frontal plane through the cusp tips of both the right and left molars?
Curve of Wilson
What does the Curve of Wilson do in the Class I ideal bite?
Allows movement used in chewing functions
What is the difference in space between the max and mand teeth at rest vs in occlusion?
Freeway space
What does freeway space usually measure in mm?
2-3mm
Night guards acrylic thickness artifically maintains freeway space. What can this result in?
This may retrain the muscles into relaxing when at rest
What are the factors that influence the development of the occlusion?
Biologic (heredity)
Pathological (unknown origin)
Environmental (habits)
What is the number one influence for a malocclusion?
Hereditary
What are examples of pathological development factors that can affect occlusion?
Cleft palate
Missing teeth
Ectodermal dysplasia
Facial asymmetries
Nasopharyngeal disease and respiratory function
What are examples of environmental factors that affect the development of occlusion?
Mouthbreathing
Thumbsucking/pacifier
Lower lip biting
Atypical swallowing causing incorrect tongue posture
What is the number one cause of malocclusion?
Habits causing interference of facial and masticatory muscles
What must be done during the extraoral assessment?
Assess the skeletal pattern
Assess the soft tissue
What must be assessed during the skeletal pattern assessment?
Anterior-Posterior Dimension
Vertical Dimension
Transverse Dimension
In an anterior-posterior dimension assessment, Class I has the mandible ____ and the profile is____
2-3mm posterior to the maxilla
Straight
In the anterior-posterior dimension assessment, Class II has the mandible ___ and the profile is ___
Retrusive in relation to the maxilla
Convex
In the anterior-posterior dimension assessment, Class III has mandible ____ and the profile is ____
Protrusive in relation to the maxilla
Concave
What type of x-ray is used to assess the anterior-posterior dimension?
Cephalometric radiograph
Vertical dimension can influence the amount of
Incisor overlap (overbite), lip comptence and overall facial aesthetics
How is vertical dimension assessed?
A facial anaylsis is done to compare upper to lower facial height
What is assessing the facial symmetry and arch width?
Transverse dimension
How is facial symmetry assessed?
By looking at the midline and analyzing how the nose, middle part of the upper lip and th chin line up
How is arch width assessed?
By looking at the how wide or narrow the maxilla is in relation to the mandible
What does a narrow maxilla often result in?
Crossbites
What is assessed during the soft tissue extraoral assessment?
The lips - fullness, tone, lip line, competence
What are the adjectives used to assess the lips fullness relative to the e-line?
Protrusive
Straight
Retrusive
What are the adjectives used to to assess the lips tone?
Flaccid
Normal
Highly active
Where should the lip line lie?
Ideally the lower lip lies at that middle third of the max central incisor
Define lip competence
Oral seal requires minimal muscular effort
Define lip incompetence
Oral seal requires excessive muscular effort
What must be assessed during the intraoral assessment?
Tongue
Habits
Mandible closure/TMJ
Pathologies
Dentition
Oral hygiene
How should the tongue be assessed during IO assessment?
Attempt to observe without asking the client. Difficult to assess unless grossly abnormal. During function an adaptive tongue thurst may be observed.
How to assess TMJ during IO assessment?
Recognize any disfunction - tender muscles of mastication, clicking or crepitus, range of movements including any deviations
What pathologies to assess during IO assessment?
Mucosal surface
Caries
Hypoplasia
Hypomineralization
Tooth wear
Traumatic injury
Recession
Gingivitis
Periodontitis
What to assess for dentition during IO assessment?
Occlusion
Tooth position within arches - crowding/spacing/inclination/frenal attachment/overjet/overbite/crossbite/occlusional interferences
Eruption timing and pattern
Macro/microdontia
Impacted/missing/supernumerary teeth
What to assess for oral hygiene during IO assessment?
GI
PI
PD
Decal
Diet
Gingival hyperplasia
Appliance-related stomatitis
When is it important to assess and review OH?
Before, during, and after ortho
What types of orthodontic diagnostic records are needed?
Study models (impressions, bite reg)
Radiographs (pan/ceph/FMS)
EO/IO photos
Tomography (CT scans)
What type of occlusion has the normal molar relationship but the incorrect line of occlusion?
Class I malocclusion
What are the characteristics of a Class I malocclusion?
Normal molar relationship but incorrect line of occlusion
Normal skeletal/muscle relations
May have tooth to jaw size discrepencies (retrusion, protrusion, over bites, open bites, cross bites)
Orthogranic profile
Arch shape is ovoid
How does the muscle pattern of the tongue, lips, and mentalis muscle appear in a Class I malocclusion?
Tongue - tip rests betwen 12-22, dorsum of the tongue approximates the hard palate. Tongue and cheek muscles are in harmony
Lips - rest in harmony
Mentalis muscle - relaxed
When should a Class I malocclusion be referred?
Age 10
What are the characteristics of a Class II Div 0 malocclusion?
Disto-occlusion
Max 6’s cusps are ahead of the grove in the mand 6’s
Maxilla is prognathic/mand is retrognathic
What are the characteristics of a Class II Div 1 malocclusion?
Same as Class II Div 0 but with anterior teeth having overjet and/or an openbite
Over erupted mandibular anteriors are often present
Tongue thrusting occurs to close the open bite
Dolichofacial
Convex/retrognatic profile
Long and narrow arch shape
What are the muscle patterns of the tongue, lips, and mentalis muscle in a Class II Div I malocclusion?
Tongue - pushed forward to contact the lower lip (adaptive tongue thrust)
Lips - upper lip rests on the labial surface of the maxillary centrals and laterals. Lower lip is strong and raises to close the space to the upper lip
Mentalis muscle - is overactive to raise the lower lip creating a dimpled chin appearance
What age to refer a Class II Div I malocclusion?
Age 7
What is needed with habits to cause issues?
Time - continuous, intermittent, age level
Early excessive thumb sucking causing an open bite malocclusion results in ____ syndrome.
Long face
What are the characterisitics of a Class II Div II malocclusion?
Same molar relationship as Class II Div 0/1
Deep anterior overbite
Lingually inclined max centrals
Labially placed laterals
Mand arch had little to no crowding
Pronounced soft tissue profile due to lack of vertical height
Brachyfacial
Straight profile
Wide arch shape
What are the muscle patterns of Class II Div II malocclusions?
Tongue - normal
Lips - lower lip curls and tends to have more resting posture with excess of soft tissue (thicker lip)
Often higher up lip line (gummy smile)
Chin - often prominent creating a deep labiomental fold (excessive chin button) due to lack of vertical height
Class II Div II skeletally resembles
Class I
True or False: Class III malocclusions have strong genetic predispositions.
True
Characteristics of Class III malocclusion
Underbite from overgrowth of mandible
Possible anterior crossbite
Labial inclination of the max incisors and lingual inclintion of mand incisors
Brachyfacial
Concave/prognathic profile
Long arch shape
What are the muscle patterns with Class III malocclusion?
Tongue - lower than normal, pushes the max incisors forward, and mand incisors backwards
Lips - upper lip is short and rests on max incisors. Lower lip is stronger forcing mand incisors backwards
Mentalis - tight and it aids in the lower lip action
What is hypotonic?
Upper lip is flaccid
What is hyptertonic?
Lower lip is tight
What are neurological re-education education exercises to assist the normalization of the developing, or developed, craniofacial structures and function?
Orofacial Myofunctional Therapy (OMT)
True or False: OMT can be applied to retrain the tongue to a better position/movement to eliminate issue prior to or inconjunction with ortho?
True
What are the four main goals of OMT?
Nasal breathing
Lip seal
Tongue posture
Proper swallowing pattern
When was OMT first recognized and discussed?
1960
OMT considers the position of ____ as a cause of malocclusion.
The tongue
How does a Myobrace appliance work?
Causes tongue to position correctly
Swallowing is corrected
Lip bumpers stop lower lip from pushing back
OMT may include:
DDS
RDH
Orthodontist
Speech pathologist
ENT
Physical therapist
Occupational therapist
Study diagram from Page 29 of study guide
