lec 12 Flashcards
SELECTION OF TEETH SIZE
3 Dimensions:
- Height (occlusogingivat)
- Width (mesiodistal)
- Thickness (faciolingual) - less significant
DETERMINING TOOTH WIDTH
Anthropometric measurements (4)
- Bizygomatic width
o Bizygomatic width / 3.3 = width of 6 upper anterior teeth
o Bizygomatic width / 16 = width of single incisor - Cranial circumference
o Cranial circumference: combined upper anterior width = 10: 1 - Corner of the mouth at rest = distal surface of the canine.
- Ala of the nose = midline of the canine.
GUIDE TO VERTICAL HEIGHT
* High lip line = _____________________
o Incisogingival length should be ________________________
- Interarch space = ________________
Exposed occlusion rim when patient smile
greater than this so that the denture base does not show too much during smiling.
reduced interarch space would require the use of shorter teeth
SELECTION OF TOOTH FORM
- 3 important forms:
- Select a form that is in harmony with the face as well as personality of the patient.
- 3 important forms:
o Facial form
o Lateral or proximal form
o Incisal form
DENTOGENIC CONCEPT
- The concept of dentogenics and dynesthetics was proposed by Frush and Fisher.
- According to the concept, teeth were selected and shaped based on sex, then personality and finally, the age.
- Sex
o Female (Feminine character) - delicate appearance by rounding corners, avoid sharp angles and contours, smaller lateral incisors, placing it at a higher level than central incisor.
o Male (Masculine character) - darker teeth with sharp angles, wider lateral incisor placed almost at the same level as the central incisor.
- Personality
o Vigorous looking - wider centrals, worn canines and central incisor, darker colors, sharp & point line angles.
o Delicate looking - pale, rounded, feminine looking.
- Age
(4)
o Grinding incisal edges to create effect of wear facets, proximal wear, more teeth can be exposed to indicate gingival recession, darker shade.
SELECTION OF THE COLOR
PROPERTIES OF COLOR
Color is recognized by the human eye when a light of a particular wavelength is reflected off an object.
Properties of color:
* Hue - basic color
* Chroma (saturation) - degree of saturation/ amount of color.
* Value (brilliance) - amount of black or white present in the object.
* Translucency - property of an object which permits the passage of light through it.
COLOR OF NATURAL TEETH
* Age -
* Canine -
* Sex -
teeth progressively darken with age. Deposition of secondary dentin makes the tooth more saturated.
darker than central incisors.
female tend to have lighter teeth than males.
- Demineralization -
areas that are not brushed regularly, commonly in the cervical regions where plaque accumulate. Demineralized enamel absorb more stains. Ranges from mild to severe (yellowish to deep brown color).
- Extrinsic stains -
over the years teeth may accumulate stains especially from food, drinks(tea), medicine, habits chewing betel nut leaves, tobacco and smoking).
- Intrinsic stains -
o fluorosis stains appear as white streaks and patches (chalky white).
o Severe fluorosis gives rise to enamel defect and severe yellow to brown stains.
o Tetracycline stain are due to effect of drugs taken during tooth development.
used to select the color.
shade guide
- Color is selected in three position:
o Outside the mouth along the side of the nose (in harmony with skin color) - establishes the basic color.
o Beneath the lips with only the incisal edge showing - simulates tooth exposure when the mouth is relaxed.
o Beneath the lips with only the cervical edge covered and most of the tooth exposed (as in smile) - reveals the tooth as in a smile.
Anterior teeth are ___________ when a person smiles, laughs or talks. For these reason, _______ would play a major role in the selection of anterior teeth
most often visible
ESTHETICS
Posterior teeth are selected primarily for ____________.
occlusal function and for comfort and preservation of the residual alveolar ridge
REQUIREMENTS OF POSTERIOR TEETH (CDCNEN)
- Should be able to chew food efficiently.
- Should contribute to denture stability.
- Should be comfortable to the underlying soft tissue.
- It should not cause any bone resorption.
- It should contribute to esthetics.
- It should not create any sound on impact.
Mastication -
posterior teeth should be able to cut and grind food effectively. Cusped teeth are more effective at grinding food than flat or monoplane teeth.
Preservation of ridge -
cusped teeth have inclined surfaces which can transmit nonvertical or lateral forces to the ridge.
o Therefore, when using cusped teeth, the occlusion should be balanced.
o Flat or monoplane teeth exert less lateral forces.
Denture stability -
upper and lower posterior teeth must meet simultaneously and evenly when the patient occludes the teeth.
Premature contact or prematurity happens when __________
one or more teeth contact before the others, it creates instability and reduced retention.
o Balancing occlusion will improve stability of the denture.
Soft tissue contact -
occlusal prematurity can create pain or sore spots underneath the denture.
Esthetics -
buccal surface of maxillary premolars and occasionally molars are often visible during smiling and certain other facial expression.
