Lecture 4 Flashcards
Biological contours
stimulate natural, healthy teeth. Protect the supporting tissues.
maintain the health of gingiva + periodontum
minimize trauma and irritation to bony tissues.
Improper contours
often induce early breakdown of supportive structures.
result in early loss of teeth.
Crest of Curvature
Height of Contour - facial and lingual convexities
Mesial and distal HOC
contact
The proper degree of curvature will deflect
food over the gingival margin preventing irritation.
The proper curvature allows stimulation
of soft tissue
If the curvature is absent, the
gingival tissue will be driven apically and this will result in pathological changes.
If the curvature is too great, the gingiva is protected too much and loses
gingival tone. Food and debris may pack under this area and result in chronic inflammation of the gingiva.
*No more than 1/2 mm. facially
beyond the CEJ.
Exception: mandibular second premolar and molars
3/4 to 1 mm. lingual
Teeth move in place, rubbing
increases contact size over time
Lingual embrasures are always larger than buccal embrasures except
maxillary first molar (where the facial embrasure is wider) and between the mandibular centrals (where the facial and lingual embrasures may be the same size).
Emergence Profile
Tooth surface that is gingival to height of contour and above the gingival crest
The profile of the gingival third of a restoration as it emerges from the gingival crevice.
It should be flat for 2-3 mm above the
gingiva.
PROXIMAL SURFACES ARE ALWAYS FLAT OR SLIGHTLY CONCAVE BETWEEN THE
CONTACT AREA AND THE CEJ TO ALLOW ROOM FOR THE PAPILLAE
Contact area
The area of the mesial or distal surface of a tooth which touches it’s neighbors. It is similar to a ball to ball point contact. It can have various locations.
Basic Functions of Contact Area:
- Aids in proper development of the arches.
- Prevents food from packing between the teeth.
- Allows the teeth to be self- cleaning (to some extent).
- Prevents injury to the interproximal tissues.
Contact Areas
Contact areas of all posterior teeth should be buccal to the central fossa and in the occlusal third
In occlusal 1/3 - contact
Exception - between max molars (junction of middle and occlusal
Buccal to buccolingual center - contact exception
Max molars are in center 3rd.

Marginal ridges converge from

buccal to lingual (facial 1/2 is wider than lingual 1/2)
Marginal ridges converge from —– except!
Mandibular 2nd premolar 3 cusp type and Maxillary first molar
functions of Embrasures
- It is a spillway for the escape of food during function.
2. It help maintain the tooth clean
Cervical Curvature
Margins of restoration often end at the cervical line or CEJ. This line curve occlusally at the proximal and apically at the facial and lingual. The curvature relates to the contour of the bony alveolar area.
“BIOLOGIC WIDTH”
1.5 to 2 mm from margin to bone.
An over-contoured crown results directly from inadequate
tooth reduction and causes a lack of room for biomaterials.
Placing the margins of restorations subgingival
can cause inflammation and
reduction of gingival height.
For subgingival margins it is wise to consider using a
consider using a metal margin, which is easily tolerated by the tissues. If esthetics
is a concern zirconia crowns are very compatible with tissues.
