Week 3 Caries, Matrix, Dental Dam Flashcards
T or F Teeth are composed of inorganic elements (96% in enamel, 70% in dentin), organic elements, and water
true
Inorganic elements in teeth
calcium, phosphate, hydroxyl group = hydroxyapatite crystals
What is the Ca/P ratio
2.15
Cariogenic bacteria
strep mutans, lactobacilli, etc
The following factors contribute to demineralization:
Higher oral bacterial load - Results in more acid production
Frequent snacking- Allows less time for remineralization
Poor oral hygiene - Increases plaque and sugar remains longer
Decreased saliva production
Caries formation is positively associated with the following activities:
Frequent or prolonged contact of the teeth with sugary substances.
Consumption of sticky foods.
Regular use of medications that contain sucrose, including some multi-vitamins.
Why does saliva aid in remineralization?
Acts as a buffer to return the pH above the demineralization level, strengthens tooth enamel, and is a fluoride source
Black’s Classification System for caries
- Class I – Occlusal
- Class II – Posterior proximal * Class III – Anterior proximal * Class IV – Incisal
- Class V – Cervical
- Class VI – Caries in cusps
Class IV prep
incisal
Class II prep
posterior proximal
Class I prep
occlusal
Class III prep
anterior interprox only
Class V prep
cervical
Class VI prep
cusp tip
The mechanical alteration of a defective, injured, or diseased tooth in order to best receive a restorative material which will re-establish a healthy state for the tooth including esthetic corrections where indicated, along with normal form and function.
Cavity Preparation
Factors Affecting Tooth Preparation
General Factors
* Diagnosis
* Prevention
* Interception * Preservation * Restoration
Patient Factors
* Economic status
* Age
* Choice of material
Principles of cavity prep
–access and see the diseased tissue
–remove caries lesion
–cut away significantly unsupported enamel
–extend margins so they are accessible for instrumentation and cleaning
Simple tooth preparation
Only one tooth surface is involved
Compound tooth preparation
Only two tooth surfaces are involved
Complex tooth preparation
Involves three or more surfaces
Internal Wall Prep
prepared surface that does not extend to the external part of the tooth surface (including axial and pulpal walls)
Axial Wall of prep
internal wall parallel with long axis of the tooth
Pulpal wall of prep
internal wall perpendicular to the long axis of the tooth and occlusal of the pulp
External wall of prep
the prepared surface that extends to the external tooth surface, including
Floor/Seat
A floor is a prepared wall that is reasonable flat and perpendicular to the occlusal forces that are directed occlusogingivally.
Enamel Wall
A portion of a prepared external wall consisting of enamel.
Dentinal Wall
the portion of a prepared external wall consisting of dentin in which mechanical features can be located.
Where is the pulpsoaxial line angle in a class II prep?
the line where the pulpal wall and axial wall meet, right where the proximal box begins
Cavo-Surface Angle
is the angle of the tooth structure formed by the junction of a prepared cavity wall and the external surface of the tooth.
What class are OL and OB preps?
Class I, if it’s the in the occlusal 2/3 of the B and L surfaces of molars
What class prep are palatal pits of the maxillary incisors?
Class I
Can an anterior tooth be class II prep?
no
Do all class III lesions require a F or L surface?
no, it can be a straight M or D if accessible without a F or L prep
Do class III lesions involve the incisal edge?
no, that would be a class IV
Can class V lesions be proximal?
Yes, carious lesions in the cervical third that do not involve the margin.
Posterior tooth straight mesial prep in the middle third without access in the cervical third or margin would be what class?
I DON’T KNOW
Steps to stage I of the prep
- Obtain outline form and initial depth
- Primary resistance form
- Primary retention form
- Convenience form
Steps stage 2 final tooth prep steps
- Removal of remaining carious dentin
- Providing pulp protection if indicated
- Obtain secondary resistance and retention form * Finishing of enamel walls and margins
- Final procedures; Cleaning, inspecting and sealing.
Features of Resistance Form
-shape and placement of cavity walls
-Box shaped preparation
- Flat pulpal and gingival floor (helps the tooth resist forces)
-Adequate thickness of material to not break the filling or the tooth
-don’t extend too far so the marginal ridges are still strong
-include weak structure so it won’t break
-round internal line angles reduce stress
In resistance form, amalgam requires a minimal thickness of ____
1.5 mm
In resistance form, porcelain requires a minimal thickness of ____
2mm
In resistance form, cast metal requires a minimal thickness of ____
1mm
In resistance form, composite/glass ionomer requires a minimal thickness of ____
2.5mm
Which tooth is the pulpal wall prepped NOT flat?
mand 1st premolar, because the lingual cusp is so small, the pulpal floor is parallel to imaginary line joined the tips of the B and L cusps.
Retention form
Shape and configuration of the tooth preparation that resists the displacement or removal of the restoration from the preparation while under the influence of lifting and tipping during masticatory forces.
Factors affecting retention:
-Amount of stresses falling on the restoration
-Thickness of the restoration
-Total surface area of the restoration exposed to the masticatory forces -Amount of remain tooth structure.