1 Fundamental and Preventive Curvatures of Teeth

-disease
-damage
-bacterial invasion
-calculus buildup

curvatures of the teeth aid in preventing:

disperse

curvatures _____________ occlusal trauma

gingiva and periodontium

curvatures protect the __________ and ______________

increase the life expectancy of a tooth and its surroundings

these curvatures help...

characteristics of shape and alignment

1. size and location of proximal contacts
2. size and location of interproximal spaces
3. location and effectiveness of embrasures
4. facial and lingual contours of the crown
5. amount of curvature of CEJ on mesial and distal surface
6. self cleaning qualities of the tooth
7. occlusal and incisal curvatures and contours

proximal contact areas

mesial or distal surfaces of the teeth where contact occurs with an adjacent tooth

-prevent food from packing between teeth (protect the gingiva)
-prevents build up of bacteria and plaque
-offer support and resistance from traumatic forces (stability in the arch)

what do proximal contact areas do?

widest portion and greatest curvature

contact areas are found on mesial and distal surfaces at the _________________ and _______________

distal; mesial

the ______ contact area of one tooth touches the ______ contact area of the tooth posterior to it

contact point

where the occlusal cusp of one tooth touches the occlusal portion of another tooth in the opposing arch (upper and lower)

interproximal spaces

triangular spaces found between the teeth

formed by bone, proximal surfaces of teeth, and contact areas of teeth

what are interproximal spaces formed by?

interdental papilla

gingival tissue that normally fills interproximal spaces

cervical embrasure

the void if gingival recession occurs with bone and tissue not filling the space

embrasures

v-shaped spaces between adjacent teeth that are found around the contact area

allow for passage of food so it is not forced into the contact area

what do embrasures do?

named for their location in relation to contact area
-buccal/facial
-lingual
-incisal/occlusal
-gingival (cervical)

how are embrasures named?

1. keep food from being packed between the teeth
2. reduce the forces of occlusal trauma, to prevent food from collecting
3. self cleaning, rounded smooth surfaces
4. stimulate the gingiva and protect gingiva from undue trauma

purposes of embrasures

closer to incisal surface

location of contact areas facial view: anterior teeth

closer to middle third of the teeth

location of contact areas facial view: posterior teeth

the distal of the canine contact is more cervical than the 1st and 2nd premolars

more posterior the tooth the more cervical the contact except...

wider

the more posterior teeth have ________ embrasures than the most anterior

contact in center between labial and lingual

location of contact areas occlusal view: anterior teeth

contact buccal to the center of teeth (creates a larger V on lingual to push food towards tongue)

location of contact areas occlusal view: posterior teeth

larger

lingual embrasures are _______ than buccal/facial embrasures

-degree of these contours allow for deflection of food
-lingual contour allows for tongue to rest for proper cleaning
-these keep tissue stimulated and prevent food from entering gingival crevice

what do facial and lingual contours do?

buccal/facial height of contour

-crest of curvature
-for all teeth found in the cervical third

lingual height of contour

-crest of curvature
-anterior teeth = cervical third
-posterior teeth = at or near middle third

mesial; distal

more curvature at CEJ usually seen on the ________ than the _________ surface for all teeth

anterior; posterior

_________ teeth have more curvature of cervical line than _________ teeth (allows for more attachment of tooth surface to bone)

-smooth enamel
-shape of crown
-shapes of teeth
-pits and fissures on occlusal surfaces

self cleaning qualities of the teeth:

smooth enamel

prevents food and bacteria from sticking

shape of crown

prevents gingival irritation and helps keep gingiva clean by deflecting food

shapes of teeth

how they chew food and deflect food to other teeth to tear, pierce, and chew

pits and fissures on occlusal surfaces

act as spillways and help in supporting occlusal forces

-open contacts
-recession
-restorations
-overhanging restoration

periodontium issues that can arise:

open contacts

when teeth do not touch at their contact areas (natural or faulty restoration)

allows for food and debris to collect between the teeth and lead to periodontal issues

what do open contacts do?

recession

loss of tissue away from the tooth

deflection of food at an extreme angle too much tissue stimulation

what can cause recession?

restorations

overfilling or underfilling can cause damage (fillings should be smooth with tooth surface)

overhanging restorations

too much restoration that acts as hard place to clean. can lead to perio issues, decay, and accumulation of bacteria and food debris