Random questions Flashcards
have a full knowledge of dental material and associate dental cases
what happens if all teeth of 1 half of the dental arch are pulled out
the patient will eventually limp on the opposite side (meaning , if all right teeth were oulled out then he will limp on his left)
ما الفرق بين التسمم و الانسمام و ما نتيجة كل منهما
التسمم هو ingestion of mercury for example will lead to loss of healthy teeth
اوا الانسمام هو شرب كيات قليلة على فترات زمنية طويلة for example fluorisis which results from excess ingestion of fluoride when the are forming which may disfigure or discolor the theeth
what are the most teeth prone to congenital loss or disease
MAXILLARY lateral incisors either because of impefect amelogenisis( issue in enamel formation)or imperfect dentinogenisis . in the latter cases, tooth must be pulled out
what is amelogenisis
Amelogenesis is the formation of enamel on teeth and begins when the crown is forming during the advanced bell stage of tooth development after dentinogenesis, forms a first layer of dentin. Although dentin must be present for enamel to be formed, ameloblasts must also be for dentinogenesis to continue.
what are dental restorative materials
they arw used to prevent or repair damage to teeth caused by oral disease or trauma
what are caries (tooth decay , tooth cavities)
the accumalation of bacterial plaque in areas of teeth where patient prophylaxis does not remove .
what is prophylaxis
a medical term for proceduress that promote oral health
what is periodontal disease
unlike caries, it affects the tissues surrounding the tooth like ( gingiva, periodontal ligament, cementum, alveolar bone)
what is the difference between caries and periodontal disease
caries takes months to evolve while periodontal disease takes years, also caries affects the tooth itself whereas periodontal disease affects the tissues surrounding the tooh
define edentulism (caused hy osteoporosis)
the complete loss of all natural dentition
what are the teeth that are prone to be congenitally missing
maxillary lateral incisors
when are endodontic restorative materials used
when pulpal or periapical tissues are damaged
these restoration are generally small and used to repair minor trauma or caries
intracoronal restoration
these restorations generally replace large portions of the external part of the tooth, because destruction of tooth is extensive and the is insufficient structure to retain intracoronal restoration
extracoronal restoration
extracoronal preps nearly always must be restored using direct or indirect techniques
indirect techniques ( indirect restoration involves making a model of the prep them fabricating the restoration on the model from alloy, ceramic , or acrylic
give 3examples of intracoronal direct restorations
amalgam, composite, and sealant restorations
when is endodontic treatment necessary
if oral disease or trauma involves the pulp of the tooth
what is used when infected pulpal tissue is removed
sealers that prevent ingress of bacteria, the filling material usually used is gutta percha
clinical case where all natural dentition is lost
edentulism
if one to four adjacent teeth have been lost, the function and esthetics of those teeth may restored using what
a fixed partial denture( aka bridge)
how is a bridge classically prepared
placing extracoronal crowns on the abutment teeth
what are the teeth adjacent to the edentulous space called
abutment teeth
what are the artificial replacement teeth called
pontics
what are pontics
they are artificial replacement teeth used in fixed partial dentures
in the event that the abutment teeth are healthy what alternative technique can be used
Maryland bridge ( resin-bounded fixed partial denture)
how does the maryland bridge differ from the classical bridge
the latter requires substantial sacrifice of abutment tooth structure unlike the Maryland bridge where extracoronal crown are not needed, instead the arms of th pontic are resin bounded lingually to the abutment teeth
if multiple teeth are missing in multiple locations what technique is used
removable partial denture
edentulism requires what
complete denture
what is sorption
absorption and adsorption considered as a single process
name 4 factors that influence what restorative materials to use
its effect on oral tissue
possible toxic effects if ingested
color
optic qualities
name the 5 properties of dental materials
dimensional change electrical properties solubility sorption mechanical properties
why is dimensional change important during dental procedures such as prep of impressions or models
for the accuracy if dental restoration
why is THERMAL dimensional change imp
restorative dental materials are subjected to tem changes in the mouth
what is the linear thermal coefficient of expansion
is a measure of how much it expands per jnit length if heated one degree higher
define percolation
is a way for bacteria to bypass your tooth’s main layer of protection–the enamel–to attack it from within. By traveling along thedentalfilling, bacteria can reach your dentin. Dentin is actually porous, it has tiny tubules that lead right to the tooth pulp.
why is percolation thought to be undesirable
because of the possible irritation of the dental pulp and recurrent decay
name the dental material in which percolation decreases with time after insertion and why
dental amalgam, as a result of the space being filled with corrosion products from the amalgam
thermal conductivity of the tooth
human enamel and dentin are POOR thermal conductors compared with gold alloys and amalgam ( although amalgam is substantially lower than gold) GIC bases closely replace lost tooth structure with respect to thermal conductivity
why do we hse cements as thermal insulating bases in deep cavity preps
although dentin is a poor thermal conductor, a thin layer of it does not provide enough thermal insulation for the pulp unless a cement base is used under the metal restoration
why dont composite restorations present a problem with thermal conductivity
because their thermal conductivity is similar to that of the tooth structure
what are the two electrical prperties if dental materials that are of our interest
galvanism and corrosion
Define galvanisim
is the generation of an electrical current in the patients mouth as a result of the presence of unsimilar metals in the mouth
define an electrolyte
is is a liquid that contains ions (in our case it is saliva or oral fluids)
crowns are made of alloys of which material that has a strong tendency to go into solution ( dissolve) and has an electrode potential of +1.33 V
aluminum
what two restorations, that if came into contact inthe mouth cause the patient to feel pain and induces a metallic taste in the mouth
temporary aluminum alloy crown and a gold crown
what kind of temp crowns are used to avoid galvanism and why
temporary POLYMER crowns, because they are poor electrical conductors
Define corrosion, give an example state why
is the dissolution of metals in the mouth, Dental amalgam. because it reacts with chlorides and sulfides in the mouth which causes them to becom dull and discolored with time
name the process in which polished amalgam becomes dull and discolored with time and why
TARNISH, because amalgam reacts with certain chem in the mouth such as chlorides and sulfides.
Define absorption and give an example
is the uptake of liquid by the bulk solod; the equilibrium absorbtion kf water by acrylic polymers is in the range of 2 %
Define adsorption and give an example
is the concentration of molecules at the surface of a solid or liquid ; the adsorption of components of saliva at the surface of the tooth
why are zinc phosphate cements considered more soluble in the mouth than in lab tests waters indicate
because materials in the mouth are covered in plaque are exposed to various acids and organic materials
define wettability
is a measure of the affinity of a liquid for a solid as indicated by spreading of a drop
knowledge of what is esential in understanding the mech prop of dental materials
the magnitude of biting forces
name the 5 types of stress that may occur when force is applied to a material
compression tensile shear bending moment twisting moment
what is the difference between compression and tensile stress
compression is when a material is squeezed while tensile stress is when a material is pulled apart
define strain
strain is the change in length or the deformation per unit length
define preventive materials and give 3 examples
are dental materials designed to prevent disease or injury to the teeth and supporting tissues. flouride gels, pits and fissure sealants, mouth protectors
what is the importance of fluoride ion
its effectiveness in reducing the incidence of dental caries
etchants are generally composed of what
37% of phosphoric acid in water
etchants are generally composed of what
37% of phosphoric acid in water
which step is critical to the success of the sealant and why
drying the washed tooth for 15 seconds, because moisture interferes with the retention of the sealant by the fissure
what are the steps of manipulating sealants that must be followed sequentially
cleansing and etching the occlusal surface, washing these areas, DRYING THEM, applying the sealant to the pit and fissure, polymerizing and finishing.
what is the concentration of fluoride in a typical commercial acidulated phosphate fluoride gel
1.22 to 1.32 %
why containers in which the sealants are supplied must be closed tightly
to minimize the evaporation of volatile monomers which would cause the sealant to become more viscous
what are the main cariogenic bacteria
Streptococci and lactobacilli
