NEET MDS Synopsis
Thalassaemia
General Pathology
Thalassaemia. Genetic based defect in synthesis of one of the normal chains.
Beta thalassaemia ---> reduced Hb A and increased HbF (α2, Y2) HBA2(α2)
Alpha thalassaemia ---> reduced Hb-A, Hb-A2 and Hb-F-with formation of Hb-H(β4) and Hb Barts (Y4).
Thalassaemia may manifest as trait or disease or with intermediate manifestation.
Features:
• Microcytic hypochromic RBC is in iron deficjency.
• Marked anisopoikilocytsis with prominent target cells.
• Reticulocytosis and nucleated RBC seen.
• Mongoloid facies and X-ray findings characteristic of marrow hyperplasia
• Decreased osmotic. fragility.
• Increased marrow iron (important difference from iron deficiency anaemia).
• Haemosiderosis, especially with repeated transfusions.
Diagnosis is by Hb electrophoresis and by Alkali denaturation test (for HbF).
Social Learning Theory
PedodonticsSocial Learning Theory
Antecedent Determinants:
Definition: Antecedent determinants refer to the
factors that precede a behavior and influence its occurrence. This
includes the awareness of the child regarding the context and the events
happening around them.
Application in Pedodontics: In a dental setting, if
a child is aware of what to expect during a dental visit (e.g., through
explanations from the dentist or caregiver), they are more likely to
feel prepared and less anxious. Providing clear information about
procedures can help reduce fear and promote cooperation.
Consequent Determinants:
Definition: Consequent determinants involve the
outcomes that follow a behavior, which can influence future behavior.
This includes the child’s perceptions and expectations about the
consequences of their actions.
Application in Pedodontics: If a child experiences
positive outcomes (e.g., praise, rewards) after cooperating during a
dental procedure, they are more likely to repeat that behavior in the
future. Conversely, if they perceive negative outcomes (e.g., pain or
discomfort), they may develop anxiety or avoidance behaviors.
Modeling:
Definition: Modeling is the process of learning
behaviors through observation of others. Children often imitate the
actions of adults, peers, or even media figures.
Application in Pedodontics: Dental professionals
can use modeling to demonstrate positive behaviors. For example, showing
a child how to sit still in the dental chair or how to brush their teeth
properly can encourage them to imitate those behaviors. Additionally,
having older children or siblings model positive dental experiences can
help younger children feel more comfortable.
Self-Regulation:
Definition: Self-regulation involves the ability to
control one’s own behavior through self-monitoring, judgment, and
evaluation. It includes setting personal goals and assessing one’s own
performance.
Application in Pedodontics: Encouraging children to
set goals for their dental visits (e.g., staying calm during the
appointment) and reflecting on their behavior afterward can foster
self-regulation. Dental professionals can guide children in evaluating
their experiences and recognizing their progress, which can enhance
their sense of agency and responsibility regarding their oral health.
Muscles of the Tongue
AnatomyMuscles of the Tongue
The tongue is divided into halves by a medial fibrous lingual septum that lies deep to the medial groove.
In each half of the tongue there are four extrinsic and four intrinsic muscles.
The lingual muscles are all supplied by the hypoglossal nerve (CN XII).
The only exception is palatoglossus, which is supplied by the pharyngeal branch of the vagus nerve, via the pharyngeal plexus.
Extrinsic Muscles of the Tongue
The Genioglossus Muscle
This is a bulky, fan-shaped muscle that contributes to most of the bulk of the tongue.
It arises from a short tendon from the genial tubercle (mental spine) of the mandible.
It fans out as it enters the tongue inferiorly and its fibres attach to the entire dorsum of the tongue.
Its most inferior fibres insert into the body of the hyoid bone.
The genioglossus muscle depresses the tongue and its posterior part protrudes it.
The Hyoglossus Muscle
This is a thin, quadrilateral muscle.
It arises from the body and greater horn of the hyoid bone and passes superoanteriorly to insert into the side and inferior aspect of the tongue.
It depresses the tongue, pulling its sides inferiorly; it also aids in retrusion of the tongue.
The Styloglossus Muscle
This small, short muscle arises from the anterior border of the styloid process near its tip and from the stylohyoid ligament.
It passes inferoanteriorly to insert into the side and inferior aspect of the tongue.
The styloglossus retrudes the tongue and curls its sides to create a trough during swallowing.
The Palatopharyngeus Muscle
Superior attachment: hard palate and palatine aponeurosis.
Inferior attachment: lateral wall of pharynx.
Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
This thin, flat muscle is covered with mucous membrane to form the palatopharyngeal arch.
It passes posteroinferiorly in this arch.
This muscle tenses the soft palate and pulls the walls of the pharynx superiorly, anteriorly and medially during swallowing.
Intrinsic Muscles of the Tongue
The Superior Longitudinal Muscle of the Tongue
The muscle forms a thin layer deep to the mucous membrane on the dorsum of the tongue, running from its tip to its root.
It arises from the submucosal fibrous layer and the lingual septum and inserts mainly into the mucous membrane.
This muscle curls the tip and sides of the tongue superiorly, making the dorsum of the tongue concave.
The Inferior Longitudinal Muscle of the Tongue
This muscle consists of a narrow band close to the inferior surface of the tongue.
It extends from the tip to the root of the tongue.
Some of its fibres attach to the hyoid bone.
This muscle curls the tip of the tongue inferiorly, making the dorsum of the tongue convex.
The Transverse Muscle of the Tongue
This muscle lies deep to the superior longitudinal muscle.
It arises from the fibrous lingual septum and runs lateral to its right and left margins.
Its fibres are inserted into the submucosal fibrous tissue.
The transverse muscle narrows and increases the height of the tongue.
The Vertical Muscle of the Tongue
This muscle runs inferolaterally from the dorsum of the tongue.
It flattens and broadens the tongue.
Acting with the transverse muscle, it increases the length of the tongue.
COMPOSITE RESINS -Reaction
Dental Materials
COMPOSITE RESINS
Reaction
Free radical polymerization
Monomers + initiator. + accelerators-+ polymer molecules
Initiators-start polymerization by decomposing and reacting with monomer
Accelerators-speed up initiator decomposition
Amines used for accelerating self –curing systems
Light used for accelerating light-curing systems
Retarders or inhibitors-prevent premature polymerization
ORMOCER (Organically Modified Ceramic)
Conservative DentistryORMOCER (Organically Modified Ceramic)
ORMOCER is a modern dental material that combines organic and inorganic
components to create a versatile and effective restorative option. Introduced as
a dental restorative material in 1998, ORMOCER has gained attention for its
unique properties and applications in dentistry.
1. Composition of ORMOCER
ORMOCER is characterized by a complex structure that includes both organic
and inorganic networks. The main components of ORMOCER are:
A. Organic Molecule Segments
Methacrylate Groups: These segments form a highly
cross-linked matrix, contributing to the material's strength and stability.
B. Inorganic Condensing Molecules
Three-Dimensional Networks: The inorganic components
are formed through inorganic polycondensation, creating a robust backbone
for the ORMOCER molecules. This structure enhances the material's mechanical
properties.
C. Fillers
Additional Fillers: Fillers are incorporated into the
ORMOCER matrix to improve its physical properties, such as strength and wear
resistance.
2. Properties of ORMOCER
ORMOCER exhibits several advantageous properties that make it suitable for
various dental applications:
Biocompatibility: ORMOCER is more biocompatible than
conventional composites, making it a safer choice for dental restorations.
Higher Bond Strength: The material demonstrates superior
bond strength, enhancing its adhesion to tooth structure and restorative
materials.
Minimal Polymerization Shrinkage: ORMOCER has the least
polymerization shrinkage among resin-based filling materials, reducing the
risk of gaps and microleakage.
Aesthetic Qualities: The material is highly aesthetic
and can be matched to the natural color of teeth, making it suitable for
cosmetic applications.
Mechanical Strength: ORMOCER exhibits high compressive
strength (410 MPa) and transverse strength (143 MPa), providing durability
and resistance to fracture.
3. Indications for Use
ORMOCER is indicated for a variety of dental applications, including:
Restorations for All Types of Preparations: ORMOCER can
be used for direct and indirect restorations in various cavity preparations.
Aesthetic Veneers: The material's aesthetic properties
make it an excellent choice for fabricating veneers that blend seamlessly
with natural teeth.
Orthodontic Bonding Adhesive: ORMOCER can be utilized as
an adhesive for bonding orthodontic brackets and appliances to teeth.
Root Formation and Obliteration
Dental Anatomy
Root Formation and Obliteration
1. In general, the root of a deciduous tooth is completely formed in just about one year after eruption of that tooth into the mouth.
2. The intact root of the deciduous tooth is short lived. The roots remain fully formed only for about three years.
3. The intact root then begins to resorb at the apex or to the side of the apex, depending on the position of the developing permanent tooth bud.
4. Anterior permanent teeth tend to form toward the lingual of the deciduous teeth, although the canines can be the exception. Premolar teeth form between the roots of the deciduous molar teeth
Use of local anesthetics during pregnancy
Pharmacology
Use of local anesthetics during pregnancy
Local anesthetics (injectable)
Drug FDA category
Articaine C
Bupivacaine C
Lidocaine B
Mepivacaine C
Prilocaine B
Vasoconstrictors
Epinephrine 1:200,000 or 1:100,000 C (higher doses)
Levonordefrin 1:20,000 Not ranked
Local anesthetics (topical)
Benzocaine C
Lidocaine B
Mouthguards
PedodonticsClassification of Mouthguards
Mouthguards are essential dental appliances used primarily in sports to
protect the teeth, gums, and jaw from injury. The American Society for Testing
and Materials (ASTM) has established a classification system for athletic
mouthguards, which categorizes them into three types based on their design, fit,
and level of customization.
Classification of Mouthguards
ASTM Designation: F697-80 (Reapproved 1986)
Type I: Stock Mouthguards
Description: These are pre-manufactured mouthguards
that come in standard sizes and shapes.
Characteristics:
Readily available and inexpensive.
No customization for individual fit.
Typically made from a single layer of material.
May not provide optimal protection or comfort due to their
generic fit.
Usage: Suitable for recreational sports or
activities where the risk of dental injury is low.
Type II: Mouth-Formed Mouthguards
Description: Also known as "boil-and-bite"
mouthguards, these are made from thermoplastic materials that can be
softened in hot water and then molded to the shape of the wearer’s
teeth.
Characteristics:
Offers a better fit than stock mouthguards.
Provides moderate protection and comfort.
Can be remolded if necessary, allowing for some customization.
Usage: Commonly used in youth sports and activities
where a higher risk of dental injury exists.
Type III: Custom-Fabricated Mouthguards
Description: These mouthguards are custom-made by
dental professionals using a dental cast of the individual’s teeth.
Characteristics:
Provides the best fit, comfort, and protection.
Made from high-quality materials, often with multiple layers for
enhanced shock absorption.
Tailored to the specific dental anatomy of the wearer, ensuring
optimal retention and stability.
Usage: Recommended for athletes participating in
contact sports or those at high risk for dental injuries.
Summary of Preference
The classification system is based on an ascending order of preference:
Type I (Stock Mouthguards): Least preferred due to
lack of customization and fit.
Type II (Mouth-Formed Mouthguards): Moderate
preference, offering better fit than stock options.
Type III (Custom-Fabricated Mouthguards): Most
preferred for their superior fit, comfort, and protection.