Chu Alignment Flashcards
What are 4 things seen on the occlusal surfaces of the teeth?
Grooves, sulci, cusps, cusp ridges
(Sulcus is a broad depression or valley on occlusal surface of posterior teeth.)
The occlusal table is what % of the buccolingual dimension of the tooth?
50-60%. (It is the area within the cusps tips. Masticatory forces are applied to the occlusal table. It is positioned within the confines of the root.)
Where is the bucco-occlusal line?
It is drawn through the buccal cusp tips of the mandibular posterior teeth. It divides the inner and outer aspects of the buccal cusps.
Where is the linguo-occlusal line?
It is drawn through the lingual cusp tips of the maxillary posterior teeth. It divides the inner and outer aspects of the lingual cusps.
Where are the central fossa lines?
Drawn through the central developmental grooves of maxillary & mandibular posterior teeth.
What is inclination?
In the facio-lingual dimension. You can have TOOTH inclination or ROOT inclination. (These will be opposite)
What is angulation?
The tooth or root position In the mesio-distal dimension.
What is the angulation of all teeth?
All teeth have a mesial crown angulation and distal root angulation.
What is the inclination of facial and lateral incisors?
Facial inclination
Canines and premolars have their crown and root in the same plane in the ________ dimension.
bucco-lingual
Maxillary posterior teeth have a slight inclination toward what side?
Buccal
Mandibular posterior teeth have a slight inclination toward what side?
Lingual
What are 4 reasons to understand root angulation?
1) Tells you where to point x-ray 2) Tells you the direction of occlusal forces along long axis of tooth 3) Orthodontic force control 4) Implant placement
Where are the facial and lingual heights of contour for the anterior teeth?
Facial & lingual are in cervical 1/3
Where are the facial and lingual heights of contour for posterior teeth?
Facial = cervical 1/3, lingual = middle 1/3
What is the convexity of the facial and lingual heights of contour? What is the exception?
0.5mm, except lingual of mandibular posteriors which is 1.0mm
What are the two categories of contact areas?
Facio-lingual contact area; inciso-cervical contact area
What are 3 functions of contact areas?
1) Stabilize arch (prevent rotation, mesial drift)
2) Prevent food impaction (prevents food from being forced through the contact area)
3) Protect interproximal gingival tissue
How do contact areas change over time?
The area increases with age. It also becomes more cervical as you move from anterior to posterior teeth.
In what dimension is the contact area centered for anterior teeth?
The contact area is centered facio-lingually.
Where is the contact area for posterior teeth? Why is this significant?
More towards the buccal than the lingual. It creates a “sluiceway” or an area for food to escape.
For maxillary and mandibular anterior teeth, looking occlusally, which embrasure is larger, facial or lingual?
The lingual embrasure is larger. (Remember this is the same for maxillary and mandibular anteriors.)
For maxillary and mandibular anterior teeth, looking facially or lingually, which embrasure is larger, the gingival or incisal?
The gingival embrasure is larger. (This is the same for maxillary and mandibular anteriors.)
Looking at the occlusal surface of the maxillary premolars, which embrasure is larger, buccal or lingual?
Lingual
Looking at the occlusal surface of the mandibular posteriors, which embrasure is larger, facial or lingual?
Lingual
Where is the interproximal contact area localized compared to the central fossa line? (Is it more buccal or more lingual?)
Localized buccal to the line
What is the benefit of having lingual embrasures that are larger?
It allows food to be displaced lingually. The tongue can then return the food to the occlusal surface easily.
