Exam 1 Flashcards
What is dentistry
evaluation, diagnosis, prevention and or treatment of diseases/disorders of the oral cavity.
Purpose of Incisors
- Cut/shear food
- phonetics, function, and aesthetics
Purpose of Canines
- seize, pierce, tear, cut food
- longest roots. and strategic position in arch
- key to occlusion (protection)
Purpose of Premolars
- grind and tear
- fine chewing
Purpose of Molars
(large, multi-rooted strong)
-crushing, grinding, and chewing
Characteristics of Enamel
hard, translucent white, shell structure, striated appearance due to enamel rods that run from DEJ to surface
- very hard, brittle in parallel direction to rods
- low tensile strength in perpindicular direction to rods
Characteristics of Dentin
-softer than enamel, yellowish
-higher tensile strength due to collagen
isotropic properties
-stops propagation of cracks in enamel
-striated appearance with tubules that extend from pulp chamber to DEJ
-tubules are related to the odontoblasts
-not unifromly mineralized
% Volume composition of enamel
1-2% protein
4-8% water
90-95% hydroxyapitite
Origin of Enamel
epithelial origin
made from ameloblasts
Origin of Dentin/pulp complex
mesenchymal origin
made from odontoblasts and these odontoblasts remain in pulp
Describe the characteristics of enamel rods
- 4-8 um
- Interlocking prisms with a head region (5um wide) and a tail region (5um long)
- Rods are surrounded by an organic sheath
- Rods are made of millions of crystallites
What are the crystallites within enamel rods made of? Describe their key features
Hydroxyapitite
- needle-like
- irregular in shape, but arranged in a regular pattern within an enamel rod
- body is parallel to rod direction
- tail is up to 65 degrees from prism or rod direction - make up the surrounding organic matrix
- 200-400 Angstroms wide and 1600 Angstroms long
What is gnarled enamel
Occurs at cervical and incisal/occlusal areas and it is harder to cleave
What is interprismatic
An elaboration of dental enamel prisms that are separated by interprismatic substance and is softer than regular enamel prism and
% volume composition of Dentin
50% HA
25% collagen
25% water includes tubules
% weight composition of dentin
75% HA
20% collagen
5% water includes tubules
Purpose of dentin tubules
-allow fluid movement and ion transport to allow for remineralization, apposition of peritubular dentin and pain perception
what are odontoblastic processes
cytoplasmic extensions of the cell body (Tomes Fibers) from the dentin tubules
Tubules in superficial dentin are ______ and more ____ compared to deeper dentin
smaller and more sparsely distributed
Tubules in superficial and deep root dentin are ____ and _____ than those in comparable depths of coronal dentin
smaller
less numerous
Peritubular dentin is more mineralized than ___
intertubular dentin
Prinicpal organic component to dentin is ____. What is its purpose?
collagen (long rope-like protein)
adds toughness to dentin
How do the HA crystals within dentin differ from the HA crystals within enamel
smaller and 200-1000 Angstroms long with a 30 Angstrom diameter
What is predentin
unmineralized zone of dentin immediately adjacent to cell bodies of odontoblasts
Types of dentin
primary secondary predentin reparative dentin sclerotic dentin
when does primary dentin exist
Forms up to 3 years after tooth eruption
What is secondary dentin
the directional change of dentin and decrease in deposition without any obvious stimulus
How does dentin differ from enamel
- less mineral content
- small tubules run throughout dentin (more fluid and ion transport)
- Dentin has ability to repair or regnerate (physical chemical response and cellular response)
Four functions of dental pulp
- Formative or developmental (production of primary and secondary dentin by odontoblasts)
- nutritive (supplies nutrients and moisture to dentin through the blood vascular supply to odontoblasts)
- sensory or protectives (nerve fibers for pain, ONLY PAIN response - no differentiation)
- defensive or reparative (Inflammatory reaction to severe irritation)
Characteristics of cementum
- light yellow, slightly lighter than dentin
- lost as periodontum is lost
- removed by scaling, polishing, and abrasion
- slightly softer than dentin
- permeable to a variety of materials
Composition of cementum
5-10% mineral content
45-50% Inorganic (HA)
50-55% organic matter and water by weight (Collagen and protein polysaccharides)
HIGHEST FLUORIDE CONTENT OF ALL MINERALIZED TISSUES
How is cementum formed
- formed continually throughout life: acellular and cellular
- formed by cemtoblasts which develop from undifferentiated mesenchymal cells in the connectivetissue of the dental follicle
- can undergo self repair
What is dental caries
multifactorial transmissable, infectious oral disease caused by bacteria (biofilm)
things necessary to create a caries potential
bacteria carbohydrates tooth structure (host) time (all are needed to yield active caries)
What is the modified view of caries
dental caries is the result of interaction between cariogenic oral flora (biofilm) with fermentable dietary carbs on the tooth’s surface over time, but several modifying and protective factors influence the dental caries process
Actual caries formation depends on
variety of lifestyle factors and genetic factors including primary and secondary factors
primary modifying affecting caries development
Tooth anatomy Saliva (pH and production) Biofilm pH Use of fluoride Diet specifics Oral hygiene Immune system Genetic factors
secondary modifying factors affecting caries development
Socioeconomic status Education Life-style environment Age Ethnic group occupation
What is the view on caries at the tooth level
- caries activity is characterized by localized demineralization and loss of tooth structure
- bacteria in biofilm metabolize and produce organic acid as by-products which lowers the pH of the biofilm to below critical level.
A low pH in tooth structure causes what
calcium and phosphate to be driven from the tooth to the biofilm to reach an equilibrium that results in a netloss of minerals from the teeth. (reversing equilibrium can be done to an extent)
What is the caries balance
balance between demineralization and remineralization in terms of pathogenic vs protective factors
What are pathological factors
(Demineralization) acid producing bacteria sub-normal saliva flow Consumption of fermentable carbohydrates Poor oral hygiene
What are protective factors
(remineralization)
Saliva (buffers pH) flow and components
Remineralization (fluoride, calcium, phosphate)
Anti-bacterials (fluoride, chlorhexidine, xylitol)
Good oral hygiene
Critical pH’s of biofilm
- 5 enamel (hydroxyapatite)
- 2 dentin
- 5 enamel w/ fluoride mineralization (hydroxyfluorapatite)
What is the key to caries management
understanding the balance between demineralization and remineralization
four parts to primary etiology of caries in a patient and describe each
- Symptoms: demineralization lesions in teeth
- Treatment, symptomatic: restoration of cavitated lesions.
- Treatment, therapeutic: reverse pH equilibrium; ie, biofilm control, elevating biofilm pH, enhancing remineralization–>curing the disease.
- Post treatment assessment, therapeutic: re-evaluation of etiologic conditions and primary and secondary risk factors; and continuous management based on findings.
▪Caries lesion. Tooth demineralization as a result of the caries process. Other texts may use the term carious lesion. Laypeople may use the term cavity. ▪Smooth-surface caries. A caries lesion on a smooth tooth surface.▪Pit-and-fissure caries. A caries lesion on a pit-and-fissure area.▪Occlusal caries. A caries lesion on an occlusal surface.▪Proximal caries. A caries lesion on a proximal surface.▪Enamel caries. A caries lesion in enamel, typically indicating that the lesion has not penetrated into dentin. (Note that many lesions detected clinically as enamel caries may very well have extended into dentin histologically.) ▪Dentin caries. A caries lesion into dentin.▪Coronal caries. A caries lesion in any surface of the anatomic tooth crown.▪Root caries. A caries lesion in the root surface.▪Primary caries. A caries lesion not adjacent to an existing restoration or crown.▪Secondary caries. A caries lesion adjacent to an existing restoration, crown, or sealant. Other term used is caries adjacent to restorations and sealants (CARS). Also referred to as recurrent caries, implying that a primary caries lesion was restored but that the lesion reoccurred.▪Residual caries. Refers to carious tissue that was not completely excavated prior to placing a restoration. Sometimes residual caries can be difficult to differentiate from secondary caries.
JUST REREAD THIS….. KEEP MARKING IT AS A 1 IF YOU HAVE TO. MOST OF THEM ARE COMMON SENSE. BUT I DIDN’T WANT O LEAVE ANYTHING OUT FROM SHARPLES SLIDES- SHOOTING FOR THE B ;)
What is a cavitated caries lesion
A caries lesion that results in the breaking of the integrity of the tooth, or a cavitation.
What is a non-cavitated caries lesion
caries lesion that has not been cavitated. In enamel caries, non-cavitated lesions are also referred to as “white spot” lesions.
What is an active caries lesion
A caries lesion that is considered to be biologically act
What is an inactive caries lesion
A caries lesion that is considered to be biologically inactive at the time of examination, that is, in which tooth demineralization caused by caries may have happened in the past but has stopped and is currently stalled. Also referred to as arrested caries, meaning that the caries process has been arrested but that the clinical signs of the lesion itself are still present
What are rampant caries
Term used to describe the presence of extensive and multiple cavitated and active caries lesions in the same person. Typically used in association with “baby bottle caries,” “radiation therapy caries,” or “meth-mouth caries.” These terms refer to the etiology of the condition.
What is dental plaque
soft, tenacious film accumulating on the surface of teeth. (biofilm)
composed of bacteria, their byproducts, extracellular matrix, and water