NEET MDS Synopsis
Operant Conditioning
PedodonticsOperant Conditioning
Operant conditioning is based on the idea that an individual's response can
change as a result of reinforcement or punishment. Behaviors that lead to
satisfactory outcomes are likely to be repeated, while those that result in
unsatisfactory outcomes are likely to diminish. The four basic types of operant
conditioning are:
Positive Reinforcement:
Definition: Positive reinforcement involves
providing a rewarding stimulus after a desired behavior is exhibited,
which increases the likelihood of that behavior being repeated in the
future.
Application in Pedodontics: Dental professionals
can use positive reinforcement to encourage cooperative behavior in
children. For example, offering praise, stickers, or small prizes for
good behavior during a dental visit can motivate children to remain calm
and follow instructions.
Negative Reinforcement:
Definition: Negative reinforcement involves the
removal of an unpleasant stimulus when a desired behavior occurs, which
also increases the likelihood of that behavior being repeated.
Application in Pedodontics: An example of negative
reinforcement might be allowing a child to leave the dental chair or
take a break from a procedure if they remain calm and cooperative. By
removing the discomfort of the procedure when the child behaves well,
the child is more likely to repeat that calm behavior in the future.
Omission (or Extinction):
Definition: Omission involves the removal of a
positive stimulus following an undesired behavior, which decreases the
likelihood of that behavior being repeated. It can also refer to the
failure to reinforce a behavior, leading to its extinction.
Application in Pedodontics: If a child exhibits
disruptive behavior during a dental visit and does not receive praise or
rewards, they may learn that such behavior does not lead to positive
outcomes. For instance, if a child throws a tantrum and does not receive
a sticker or praise afterward, they may be less likely to repeat that
behavior in the future.
Punishment:
Definition: Punishment involves introducing an
unpleasant stimulus or removing a pleasant stimulus following an
undesired behavior, which decreases the likelihood of that behavior
being repeated.
Application in Pedodontics: While punishment is
generally less favored in pediatric settings, it can be applied in a
very controlled manner. For example, if a child refuses to cooperate and
behaves inappropriately, the dental professional might explain that they
will not be able to participate in a fun activity (like choosing a toy)
if they continue to misbehave. However, it is essential to use
punishment sparingly and focus more on positive reinforcement to
encourage desired behaviors.
Paracetamol
Pharmacology
Paracetamol
Paracetamol or acetaminophen is analgesic and antipyretic drug that is used for the relief of fever, headaches, and other minor aches and pains.
paracetamol acts by reducing production of prostaglandins, which are involved in the pain and fever processes, by inhibiting the cyclooxygenase (COX) enzyme.
Metabolism Paracetamol is metabolized primarily in the liver. At usual doses, it is quickly detoxified by combining irreversibly with the sulfhydryl group of glutathione to produce a non-toxic conjugate that is eventually excreted by the kidneys.
Sub-Stages of Adolescence
PedodonticsThree Sub-Stages of Adolescence
Adolescence is a critical developmental period characterized by significant
physical, emotional, and social changes. It is typically divided into three
sub-stages: early adolescence, middle adolescence, and late adolescence. Each
sub-stage has distinct characteristics that influence the development of
identity, social relationships, and behavior.
Sub-Stages of Adolescence
1. Early Adolescence (Approximately Ages 10-13)
Characteristics:
Casting Off of Childhood Role: This stage marks the
transition from childhood to adolescence. Children begin to distance
themselves from their childhood roles and start to explore their
emerging identities.
Physical Changes: Early physical development
occurs, including the onset of puberty, which brings about changes in
body shape, size, and secondary sexual characteristics.
Cognitive Development: Adolescents begin to think
more abstractly and critically, moving beyond concrete operational
thinking.
Emotional Changes: Increased mood swings and
emotional volatility are common as adolescents navigate their new
feelings and experiences.
Social Changes: There is a growing interest in peer
relationships, and friendships may begin to take on greater importance
- Exploration of Interests: Early adolescents often
start to explore new interests and hobbies, which can lead to the
formation of new social groups.
2. Middle Adolescence (Approximately Ages 14-17)
Characteristics:
Participation in Teenage Subculture: This stage is
characterized by a deeper involvement in peer groups and the teenage
subculture, where social acceptance and belonging become paramount.
Identity Formation: Adolescents actively explore
different aspects of their identity, including personal values, beliefs,
and future aspirations.
Increased Independence: There is a push for greater
autonomy from parents, leading to more decision-making and
responsibility.
Romantic Relationships: The exploration of romantic
relationships becomes more prominent, influencing social dynamics and
emotional experiences.
Risk-Taking Behavior: Middle adolescents may engage
in risk-taking behaviors as they seek to assert their independence and
test boundaries.
3. Late Adolescence (Approximately Ages 18-21)
Characteristics:
Emergence of Adult Behavior: Late adolescence is
marked by the transition into adulthood, where individuals begin to take
on adult roles and responsibilities.
Refinement of Identity: Adolescents solidify their
sense of self, integrating their experiences and values into a coherent
identity.
Future Planning: There is a focus on future goals,
including education, career choices, and long-term relationships.
Social Relationships: Relationships may become more
mature and stable, with a shift from peer-focused interactions to deeper
connections with family and romantic partners.
Cognitive Maturity: Cognitive abilities continue to
develop, leading to improved problem-solving skills and critical
thinking.
Fungal Diseases
General Medicine
Histoplasmosis
Histoplasmosis is a disease caused by the fungus Histoplasma capsulatum. Its symptoms vary greatly, but the disease primarily affects the lungs.
Occasionally, other organs are affected—this form of the disease is called disseminated histoplasmosis, and it can be fatal if untreated.
H. capsulatum grows in soil and material contaminated with bat or bird droppings. Spores become airborne when contaminated soil is disturbed. Breathing the spores causes infection.
Symptoms
they will start within 3 to 17 days after exposure.
The acute respiratory disease is characterized by respiratory symptoms, a general ill feeling, fever, chest pains, and a dry or nonproductive cough.
Chronic lung disease resembles tuberculosis and can worsen over months or years
Treatment
Antifungal medications are used to treat severe cases of acute histoplasmosis and all cases of chronic and disseminated disease
Candidiasis
Candidiasis, commonly called yeast infection or thrush, is a fungal infection of any of the Candida species, of which Candida albicans is probably the most common.
candidiasis can usually only be found in exposed and moist parts of the body, such as:
the oral cavity (oral thrush)
the vagina (vaginal candidiasis or thrush)
folds of skin in the diaper area (diaper rash)
the most common cause of vaginal irritation or vaginitis
can also occur on the male genitals, particularly in uncircumcised men.
Symptoms
itching and irritation of the vagina and/or vulva, and a whitish or whitish-gray discharge that may have a "yeasty" smell like beer or baking bread
Diagnosis
KOH (potassium hydroxide) preparation can be diagnostic
Aspergillosis
Aspergillosis is an infection or an allergic response caused by a fungus of the Aspergillus type. It may play a role in allergy, but is best known for causing serious pulmonary infections in immunocompromised patients
It causes illness in three ways:
as an allergic reaction in people with asthma
as a colonization and growth in a lung injury (such as from tuberculosis or lung abscess)
as an invasive systemic infection with pneumonia, nasal necrosis or aural inflammation and necrosis that is spread to other parts of the body by the bloodstream (pulmonary aspergillosis - invasive type).
Symptoms
Allergic aspergillosis
Fever
Malaise
Coughing
Coughing up blood or brownish mucous plugs
Wheezing
Weight loss
Recurrent episodes of lung obstruction
Invasive infection
Fever
Chills
Headaches
Cough
Shortness of breath
Chest pain
Increased sputum production, which may be bloody
Bone pain
Blood in the urine
Decreased urine output
Weight loss
Symptoms involving specific organs
Brain: meningitis
Eye: blindness or visual impairment
Sinuses: sinusitis
Heart: endocarditis
Signs and tests
Abnormal chest X-ray or CT scan
Sputum stain and culture showing Aspergillus
Tissue biopsy (see bronchoscopy with transtracheal biopsy) for aspergillosis
Aspergillus antigen skin test
Aspergillosis precipitin antibody or galactomannan positivity
Elevated serum total IgE (immunoglobulin)
Peripheral eosinophilia with allergic disease
Treatment
intravenous amphotericin B, an antifungal medication.
Itraconazole can also be used, or its newer counterpart voriconazole.
Caspofungin may be tried when other drug therapy has failed.
Endocarditis caused by Aspergillus is treated by surgical removal of the infected heart valves and long-term amphotericin B therapy.
Allergic aspergillosis is treated with oral prednisone.
Blood Supply to the Head and Neck
AnatomyBlood Supply to the Head and Neck
Most arteries in the anterior cervical triangle arise from the common carotid artery or one of the branches of the external carotid artery.
Most veins in the anterior cervical triangle are tributaries of the large internal jugular vein.
The Common Carotid Arteries
The right common carotid artery begins at the bifurcation of the brachiocephalic trunk, posterior to the right sternoclavicular joint.
The left common carotid artery begins arises from the arch of the aorta and ascends into the neck, posterior to the left sternoclavicular joint.
Each common carotid artery ascends into the neck within the carotid sheath to the level of the superior border of the thyroid cartilage.
Here it terminates by dividing into the internal and external carotid arteries.
The Internal Carotid Artery
This is the direct continuation of the common carotid artery and it has no branches in the neck.
It supplies structures inside the skull.
The internal carotid arteries are two of the four main arteries that supply blood to the brain.
Each artery arises from the common carotid at the level of the superior border of the thyroid cartilage.
It then passes superiorly, almost in a vertical plane, to enter the carotid canal in the petrous part of the temporal bone.
A plexus of sympathetic fibres accompany it.
During its course through the neck, the internal carotid artery lies on the longus capitis muscle and the sympathetic trunk.
The vagus nerve (CN X) lies posterolateral to it.
The internal carotid artery enters the middle cranial fossa beside the dorsum sellae of the sphenoid bone.
Within the cranial cavity, the internal carotid artery and its branches supply the hypophysis cerebri (pituitary gland), the orbit, and most of the supratentorial part of the brain.
The External Carotid Arteries
This vessel begins at the bifurcation of the common carotid, at the level of the superior border of the thyroid cartilage.
It supplies structures external to the skull.
The external carotid artery runs posterosuperiorly to the region between the neck of the mandible and the lobule of the auricle.
It terminates by dividing into two branches, the maxillary and superficial temporal arteries.
The stems of most of the six branches of the external carotid artery are in the carotid triangle.
The Superior Thyroid Artery
This is the most inferior of the 3 anterior branches of the external carotid.
It arises close to the origin of the vessel, just inferior to the greater horn of the hyoid.
The superior thyroid artery runs anteroinferiorly, deep to the infrahyoid muscles and gives off the superior laryngeal artery. This artery pierces the thyrohyoid membrane in company with the internal laryngeal nerve and supplies the larynx.
The Lingual Artery
This arises from the external carotid artery as it lies on the middle constrictor muscle of the pharynx.
It arches superoanteriorly, about 5 mm superior to the tip of the greater horn of the hyoid bone, and then passes deep to the hypoglossal nerve, the stylohyoid muscle, and the posterior belly of digastric muscle.
It disappears deep to the hyoglossus muscle.
At the anterior border of this muscle, it turns superiorly and ends by becoming the deep lingual artery.
The Facial Artery
This arises from the carotid artery either, in common with the lingual artery, or immediately superior to it.
In the neck the facial artery gives off its important tonsillar branch and branches to the palate and submandibular gland.
The facial artery then passes superiorly under the cover of the digastric and stylohyoid muscles and the angle of the mandible.
It loops anteriorly and enters a deep groove in the submandibular gland.
The facial artery hooks around the inferior border of the mandible and enters the face. Here the pulsation of this artery can be felt (anterior to the masseter muscle).
The Ascending Pharyngeal Artery
This is the 1st or 2nd branch of the external carotid artery.
This small vessel ascends on the pharynx, deep to the internal carotid artery.
It sends branches to the pharynx, prevertebral muscles, middle ear and meninges.
The Occipital Artery
This arises from the posterior surface of the external carotid near the level of the facial artery.
It passes posteriorly along the inferior border of the posterior belly of digastric.
It ends in the posterior part of the scalp.
During its course, it is superficial to the internal carotid artery and three cranial nerves (CN IX, CN X and CN XI).
The Posterior Auricular Artery
This is a small posterior branch of the external carotid artery.
It arises from it at the superior border of the posterior belly of the digastric muscle.
It ascends posteriorly to the external acoustic meatus and supplies adjacent muscles, the parotid gland, the facial nerve, structures in the temporal bone, the auricle, and the scalp.
The Internal Jugular Vein
This is usually the largest vein in the neck.
The internal jugular vein drains blood from the brain and superficial parts of the face and neck.
Its course corresponds to a line drawn from a point immediately inferior to the external acoustic meatus to the medial end of the clavicle.
This large vein commences at the jugular foramen in the posterior cranial fossa, as the direct continuation of the sigmoid sinus.
The dilation at its origin is called the superior bulb of the internal jugular vein.
From here it runs inferiorly through the neck in the carotid sheath.
The internal jugular vein leaves the anterior triangle of the neck by passing deep to the SCM muscle.
Posterior to the sternal end of the clavicle, it unites with the subclavian vein to form the brachiocephalic vein.
Near its termination is the inferior bulb of the jugular vein contains a bicuspid valve similar to that of the subclavian vein.
The deep cervical lymph nodes lie along the course of the internal jugular vein, mostly lateral and posterior.
Tributaries of the Internal Jugular Vein
This large vein is joined at its origin by the: inferior petrosal sinus, the facial, lingual, pharyngeal, superior and middle thyroid veins, and often the occipital vein.
Endochondral ossification
Anatomy
Endochondral ossification
A cartilage model exists
Through intramembraneous ossification in the perichondrium a collar of bone forms around the middle part of the cartilage model
The perichondrium change to a periostium
The bone collar cuts off the nutrient and oxygen supply to the chondrocytes in the cartilage model
The chondrocytes then increase in size and resorb the surrounding cartilage matrix until only thin vertical septae of matrix are left over
These thin plates then calcify after which the chondrocytes die
The osteoclasts make holes in the bone collar through which blood vessels can now enter the cavities left behind by the chondrocytes
With the blood vessels osteoprogenitor cells enter the tissue
They position themselves on the calcified cartilage septae, change into osteoblasts and start to deposit bone to form trabeculae
In the mean time the periosteum is depositing bone on the outside of the bone collar making it thicker and thicker
The trabeculae,consisting of a core of calcified cartilage with bone deposited on top of it, are eventually resorbed by osteoclasts to form the marrow cavity
The area where this happens is the primary ossification centre and lies in what is called the diaphysis (shaft)
This process spreads in two directions towards the two ends of the bone the epiphysis
In the two ends (heads) of the bone a similar process takes place
A secondary ossification centre develops from where ossification spreads radially
Here no bone collar forms
The outer layer of the original cartilage remains behind to form the articulating cartilage
Between the primary and the secondary ossification centers two epiphyseal cartilage plates remain
This is where the bone grows in length
From the epiphyseal cartilage plate towards the diaphysis a number of zones can be identified:
Resting zone of cartilage
Hyaline cartilage
Proliferation zone
Chondrocytes divide to form columns of cells that mature.
Hypertrophic cartilage zone
Chondrocytes become larger, accumulate glycogen, resorb the surrounding matrix so that only thin septae of cartilage remain
Calcification and degeneration zone
The thin septae of cartilage become calcified.
The calsified septae cut off the nutrient supply to the chondrocytes so subsequently they die.
Ossification zone.
Osteoclasts make openings in the bone collar through which blood vessels then invade the spaces left vacant by the chondrocytes that died.
Osteoprogenitor cells come in with the blood and position themselves on the calcified cartilage
septae, change into osteoblasts and start to deposit bone.
When osteoblasts become trapped in bone they change to osteocytes.
Growth and remodeling of bone
Long bones become longer because of growth at the epiphyseal plates
They become wider because of bone formed by the periosteum
The marrow cavity becomes bigger because of resorbtion by the osteoclasts
Fracture repair
When bone is fractured a blood clot forms
Macrophages then remove the clot, remaining osteocytes and damaged bone matrix
The periosteum and endosteum produce osteoprogenitor cells that form a cellular tissue in the fracture area
Intramembranous and endochondral ossification then take place in this area forming trabeculae.
Trabeculae connect the two ends of the broken bone to form a callus
Remodelling then takes place to restore the bone as it was
Joints
The capsule of a joint seals off the articular cavity,
The capsule has two layers
fibrous (outer)
synovial (inner)
The synovial layer is lined by squamous or cuboidal epithelial cells, Under this layer is a layer of loose or dense CT, The lining cells consists of two types:
- A cells
- B cells
They secrete the synovial fluid
They are different stages of the same cell, They are also phagocytic., The articular cartilage has fibres that run perpendicular to the bone and then turn to run parallel to the surface
Primary Retention Form
Conservative DentistryPrimary Retention Form in Dental Restorations
Primary retention form refers to the geometric shape or design of a prepared
cavity that helps resist the displacement or removal of a restoration due to
tipping or lifting forces. Understanding the primary retention form is crucial
for ensuring the longevity and stability of various types of dental
restorations. Below is an overview of primary retention forms for different
types of restorations.
1. Amalgam Restorations
A. Class I & II Restorations
Primary Retention Form:
Occlusally Converging External Walls: The walls of
the cavity preparation converge towards the occlusal surface, which
helps resist displacement.
Occlusal Dovetail: In Class II restorations, an
occlusal dovetail is often included to enhance retention by providing
additional resistance to displacement.
B. Class III & V Restorations
Primary Retention Form:
Diverging External Walls: The external walls
diverge outward, which can reduce retention.
Retention Grooves or Coves: These features are
added to enhance retention by providing mechanical interlocking and
resistance to displacement.
2. Composite Restorations
A. Primary Retention Form
Mechanical Bond:
Acid Etching: The enamel and dentin surfaces are
etched to create a roughened surface that enhances mechanical retention.
Dentin Bonding Agents: These agents infiltrate the
demineralized dentin and create a hybrid layer, providing a strong bond
between the composite material and the tooth structure.
3. Cast Metal Inlays
A. Primary Retention Form
Parallel Longitudinal Walls: The cavity preparation
features parallel walls that help resist displacement.
Small Angle of Divergence: A divergence of 2-5 degrees
may be used to facilitate the seating of the inlay while still providing
adequate retention.
4. Additional Considerations
A. Occlusal Dovetail and Secondary Retention Grooves
Function: These features aid in preventing the proximal
displacement of restorations by occlusal forces, enhancing the overall
retention of the restoration.
B. Converging Axial Walls
Function: Converging axial walls help prevent occlusal
displacement of the restoration, ensuring that the restoration remains
securely in place during function.
MAXILLARY CUSPIDS
Dental Anatomy
MAXILLARY CUSPIDS (CANINE)
The maxillary cuspid is usually the longest tooth in either jaw. canines are considered the corner stones of the dental arch They are the only teeth in the dentition with a single cusp.
Facial Surface:- The facial surface of the crown differs considerably from that of the maxillary central or lateral incisors. In that the incisal edges of the central and lateral incisor are nearly straight, the cuspid has a definite point, or cusp. There are two cutting edges, the mesioincisal and the distoincisal. The distoincisal cutting edge is the longer of the two. The developmental grooves prominent on the facial surface extending two-thirds of the distance from the tip of the cusp to the cervical line. The distal cusp ridge is longer than the mesial cusp ridge
Lingual Surface: Distinct mesial and distal marginal ridges, a well-devloped cingulum, and the cusp ridges form the boundries of the lingual surface. The prominent lingual ridge extends from the cusp tip to the cingulum, dividing the lingual surface into mesial and distal fossae.
Proximal: The mesial and distal aspects present a triangular outline. They resemble the incisors, but are more robust--especially in the cingulum region
Incisal: The asymmetry of this tooth is readily apparent from this aspect. It usually thicker labiolingually than it is mesiodistally. The tip of the cusp is displaced labially and mesial to the central long axis of this tooth.
Root Surface:-The root is single and is the longest root in the arch. It is usually twice the length of the crown.