Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
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            ]

            Text:
            s theory. There is lack 
of evidence that outer dentin, which is usually the most sensitive part, is innervated. 
Developmental studies have shown that the plexus of Rashkow and intratubular 
nerves do not establish themselves until the tooth has erupted; yet newly erupted 
tooth is sensitive. Moreover, pain inducers such as bradykinin fail to induce pain when 
applied to dentine, and bathing dentine with local anesthetic solutions does not 
prevent pain, which does so when applied to skin. 
Direct innervation theory 
1 
www.drcube.org Theories of Pulpal Sensitivity 
Theories of Pulpal Sensitivity 
Odontoblast receptor theory states that odontoblasts act as receptors by themselves 
and relay the signal to a nerve terminal. But majority of studies have shown that 
odontoblasts are matrix forming cells and hence they are not considered to be 
excitable cells, and no synapses have been demonstrated between odontoblasts and 
nerve terminals. 
Odontoblast receptor theory 
2 
This states that sensitivity is the result of direct thermal shock (temperature change) 
to the pulp via temperature changes transferred from the oral cavity through the tooth 
or restorative material, especially when the remaining dentin is thin. Protection from 
this insult would then be provided by an adequate thickness of an insulating material 
such as cements. 
Theory of thermal shock 
3 
www.drcube.org 
This theory based on the capillary flow 
dynamics of the fluid-filled dentinal tubule. In a 
vital tooth with exposed dentin there is a 
constant slow movement of fluid outward 
through the dentinal tubules.  
A hydrodynamic Theory 
4 
The hydrodynamic theory proposed that when 
a stimulus such as air evaporation, cold or heat 
(i.e., generated from dental bur) or tactile 
pressure these stimuli causes the slow fluid 
movement to become more rapid causing 
displacement of odonoblast cell bodies and 
stretches the intertwined terminal branches of 
the nerve plexus to allow the entry of sodium to 
initiate depolarization and the perception of 
pain. 
www.drcube.org 
As dentin near the pulp, tubule density and 
diameter increase also the permeability increase, 
thus increasing both the volume and flow of fluid. 
This 
explains 
why 
deeper 
restorations 
are 
associated with more problems of sensitivity. 
In root dentin hypersensitivity the degree of tubule 
closure from intratubular crystals was directly 
correlated with decreased sensitivity to touch, air, 
or temperature stimuli. Tooth pastes that contain 
strontium 
chloride, 
oxalates 
can 
promote 
intratubular crystallization and desensitize dentin. 
Resin bonding agents, fluoride varnishes and 
potassium and silver nitrate can also reduce dentin 
hypersensitivity by occluding dentinal tubules or 
nerve desensitization. Calcium silicate cements can 
reduce dentin hypersensitivity by remineralization 
as well. 
www.drcube.org Comparison between thermal shock and hydrodynamic theories: 
Comparison between thermal shock and

            Quiz: