Alignment and occlusion (complete) Flashcards
What things are found on the occlusal surface of the teeth
cusps
cusp ridges
grooves
sulci
What percentage of the total buccolingual dimension of the tooth does the occlusal table occupy
the occlusal table takes up 50-60% of the total buccolingual dimension of the tooth
to which part of the tooth are the mastication forces applied
the occlusal table
what are the buccal and lingual ends of the occlusal table
the buccal and lingual cusp tips
Where should the occlusal table be positioned, to give the tooth the most strength
it should be positioned within the confines of the root
What is the Bucco-occlusal line
a line drawn through the buccal cusps of the mandibular posterior teeth
Is the Bucco-occlusal line smooth and continuous, or does the location of some of the buccal cusps make it not so straight and continuous
it is straight and continuous
between what two things does the bucco-occlusal line create a division?
it creates a division between the inner and outer apspects of the mandibular centric cusps
which cusps are the mandibular centric cusps
the buccal cusps
which cusps are the maxillary centric cusps
the lingual cusps
What is the Linguo-occlusal line
a line drawn through the lingual cusps of the maxillary posterior teeth
is the linguo-occlusal line smooth and continuous
yes
between what two things does the linguo-occlusal line create a division
between the inner and outer aspects of the maxillary centric cusps
What is the Central fossa line
a continuous line drawn through the central developmental grooves of the maxillary and mandibular posterior teeth
what opposes the bucco-occlusal line
the central fossa line of the maxillary posterior teeth
what opposes the linguo-occlusal line
the central fossa line of the mandibular posterior teeth
What is another name for the mesial and distal inclines of cusps
mesial and distal cusp ridges
What is inclination
it describes the relative position of the root to crown, or crown to root, in the facio-lingual dimension
what does it mean when a tooth has a facial crown inclination
that the crown of the tooth is located facial to the root. (crown is facial root is lingual)
What does it mean when a tooth has a lingual root inclination
that the root of the tooth is located lingual to the crown of the tooth (root is lingual, crown is facial)
What is angulation
a description of the relative position of the crown to root, or root to crown, in the mesial-distal dimension
Which teeth have mesial crown angulation
all teeth
which teeth have distal root angulation
all teeth (the same thing as mesial crown angulation)
Which teeth have facial crown inclination
the central and lateral incisors of both arches
which teeth have no inclination
the canines and premolars
which teeth have a buccal crown inclination
maxillary molars
which teeth have a lingual crown inclination
mandibular molars
Why is it important to understand root angulation
- aids in aiming X-rays for better projections
- helps relate the direction of occlusal forces in restorations along the long axis of the tooth
- guides the control of orthodontic forces for proper tooth angulations
- aids in using dental implant templates with correct angulation
What is the height of contour
the greatest elevation of the tooth (the “belly” of the tooth)
What is the rule for the mesial and distal heights of contour of anterior teeth
The mesial height of contour is more incisal/occlusal than the distal height of contour
what is an exception to the rule for the mesial and distal heights of contour for anterior teeth
the mandibular central incisor. its mesial and distal heights of contour are located in the same place incisocervically
What is the rule for the mesial and distal heights of contour of posterior teeth
both mesial and distal heights of contour are in the middle third
what is an exception to the rule for the mesial and distal heights of contour of posterior teeth
mandibular premolars and possibly mandibular molars
What is the rule for the facial height of contour for all teeth
the facial height of contour is located in the cervical third on all teeth
What is the rule for the lingual height of contour for anterior teeth
it is in the cervical third of anterior teeth
what is the rule for the lingual height of contour for the posterior teeth
it is in the middle third of the posterior teeth (Except the mandibular first premolar, it is in the junction between the cervical and middle third
which teeth have facial and lingual heights of contour with a convexity of 1mm instead of the usual .5mm
the mandibular posterior teeth
what are the mesial and distal heights of contour for the maxillary teeth
IJ, JM, JM, MM, MM, MM, MM, MM
What are the mesial and distal heights of contour for the mandibular teeth
II, II, IM, MM, JJ, JM, MM, MM
What is the widest part of the tooth interproximally
the contact areas
does the contact area match up with the mesial and distal heights of contour of a tooth
yes (except if the teeth are touching, then there is no contact point, but still heights of contour)
what are the two dimensions of a contact are
incisocervical and faciolingual
what are the functions of contact areas
- stabilize the arch
- prevent food impaction
- protect interproximal gingiva
What happens to contact areas with age
- the area increases with age due to extrusion, tipping, wear
- it becomes more cervical from anterior to posterior
where are the contact points located on anterior teeth
They are centered faciolingually
Where are the contact points located on posterior teeth
more towards the buccal
why is it important that the contact points of posterior teeth are more towards the buccal than the lingual
it creates an area for food to escape = sluiceway?
What are different embrasures
- lingual embrasure
- buccal/facial embrasure
- incisal/occlusal embrasure
- gingival/cervical embrasure
is the buccal or lingual embrasure larger
the buccal embrasure’s area is larger
is the buccal or lingual embrasure wider
the lingual embrasure is wider
where is the interproximal contact in relation to the CF line (central fossa line)
the interproximal contact is located buccal to the CF line
how much of the Buccolingual distance does the contact area occupy
the contact area occupies 1/3 of the total buccolingual distance
What surrounds the contact area
the 4 embrasures
what is the purpose of embrasures
- provide a spillway for food during mastication
2. prevents food from being forced through the contact area
which embrasure is usually larger, the lingual or the buccal
the lingual (there is a discrepency in her slides. one says this, the other says that the buccal has more area)
