NEET MDS Synopsis
Early Childhood Caries
Conservative DentistryEarly Childhood Caries (ECC) Classification
Early Childhood Caries (ECC) is a significant public health concern
characterized by the presence of carious lesions in young children. It is
classified into three types based on severity, affected teeth, and underlying
causes. Understanding these classifications helps in diagnosing, preventing, and
managing ECC effectively.
Type I ECC (Mild to Moderate)
A. Characteristics
Affected Teeth: Carious lesions primarily involve the
molars and incisors.
Age Group: Typically observed in children aged 2
to 5 years.
B. Causes
Dietary Factors: The primary cause is usually a
combination of cariogenic semisolid or solid foods, such as sugary snacks
and beverages.
Oral Hygiene: Lack of proper oral hygiene practices
contributes significantly to the development of caries.
Progression: As the cariogenic challenge persists, the
number of affected teeth tends to increase.
C. Clinical Implications
Management: Emphasis on improving oral hygiene
practices and dietary modifications can help control and reverse early
carious lesions.
Type II ECC (Moderate to Severe)
A. Characteristics
Affected Teeth: Labio-lingual carious lesions primarily
affect the maxillary incisors, with or without molar caries, depending on
the child's age.
Age Group: Typically seen soon after the first tooth
erupts.
B. Causes
Feeding Practices: Common causes include inappropriate
use of feeding bottles, at-will breastfeeding, or a combination of both.
Oral Hygiene: Poor oral hygiene practices exacerbate
the condition.
Progression: If not controlled, Type II ECC can
progress to more advanced stages of caries.
C. Clinical Implications
Intervention: Early intervention is crucial, including
education on proper feeding practices and oral hygiene to prevent further
carious development.
Type III ECC (Severe)
A. Characteristics
Affected Teeth: Carious lesions involve almost all
teeth, including the mandibular incisors.
Age Group: Usually observed in children aged 3
to 5 years.
B. Causes
Multifactorial: The etiology is a combination of
various factors, including poor oral hygiene, dietary habits, and possibly
socio-economic factors.
Rampant Nature: This type of ECC is rampant and can
affect immune tooth surfaces, leading to extensive decay.
C. Clinical Implications
Management: Requires comprehensive dental treatment,
including restorative procedures and possibly extractions. Education on
preventive measures and regular dental visits are essential to manage and
prevent recurrence.
Blastomycosis (North American Blastomycosis; Gilchrist's Disease)
General Pathology
Blastomycosis (North American Blastomycosis; Gilchrist's Disease)
A disease caused by inhalation of mold conidia (spores) of Blastomyces dermatitidis, which convert to yeasts and invade the lungs, occasionally spreading hematogenously to the skin or focal sites in other tissues.
Pulmonary blastomycosis tends to occur as individual cases of progressive infection
Symptoms are nonspecific and may include a productive or dry hacking cough, chest pain, dyspnea, fever, chills, and drenching sweats. Pleural effusion occurs occasionally. Some patients have rapidly progressive infections, and adult respiratory distress syndrome may develop.
Drugs Used in Diabetes -Biguanides
Pharmacology
Biguanides
metformin
Mechanism
↓ gluconeogenesis
appears to inhibit complex 1 of respiratory chain
↑ insulin sensitivity
↑ glycolysis
↓ serum glucose levels
↓ postprandial glucose levels
Clinical use
first-line therapy in type II DM
Toxicity
no hypoglycemia
no weight gain
lactic acidosis is most serious side effect
contraindicated in renal failure
Full Mucoperiosteal Flap Design in Periradicular Surgery
EndodonticsA full mucoperiosteal flap is a critical component in periradicular surgery,
allowing access to the underlying bone and root structures for effective
treatment. This flap design includes the surface mucosa, submucosa, and
periosteum, providing adequate visibility and access to the surgical site.
Here’s a detailed overview of the flap design, its types, and considerations in
periradicular surgery.
Key Components of Full Mucoperiosteal Flap
Surface Mucosa:
The outermost layer that is reflected during the flap procedure.
Submucosa:
The layer beneath the mucosa that contains connective tissue and
blood vessels.
Periosteum:
A dense layer of vascular connective tissue that covers the outer
surface of bones, providing a source of blood supply during healing.
Flap Design Types
Two-Sided (Triangular) Flap:
Description: Created with a horizontal
intrasulcular incision and a vertical relieving incision.
Indications: Commonly used for anterior teeth.
Advantages: Provides good access while preserving
the interdental papilla.
Drawbacks: May be challenging to re-approximate the
tissue.
Three-Sided (Rectangular) Flap:
Description: Involves a horizontal intrasulcular
incision and two vertical relieving incisions.
Indications: Used for posterior teeth.
Advantages: Increases surgical access to the root
surface.
Drawbacks: Difficult to re-approximate the tissue
and may lead to scarring.
Envelope Flap:
Description: A horizontal intrasulcular incision
without vertical relieving incisions.
Indications: Provides access to the buccal aspect
of the tooth.
Advantages: Minimally invasive and preserves more
tissue.
Drawbacks: Limited access to the root surface.
Surgical Procedure Steps
Local Anesthesia:
Administer local anesthesia to ensure patient comfort during the
procedure.
Incision:
Make a horizontal intrasulcular incision along the gingival margin,
followed by vertical relieving incisions as needed.
Flap Reflection:
Carefully reflect the flap to expose the underlying bone and root
structures.
Bone Removal and Curettage:
Remove any bone or granulation tissue as necessary to access the
root surface.
Apicectomy and Retrograde Filling:
Perform apicectomy if indicated and prepare the root end for
retrograde filling.
Flap Re-approximation:
Re-approximate the flap and secure it with sutures to promote
healing.
Postoperative Care:
Provide instructions for postoperative care, including the use of
ice packs and gauze to control bleeding.
Considerations
Haemostasis:
Achieving and maintaining haemostasis is crucial for optimal
visualization and healing. Techniques include the use of local
anesthetics with vasoconstrictors and topical hemostatic agents.
Tissue Preservation:
Care should be taken to preserve as much tissue as possible to
enhance healing and minimize scarring.
Postoperative Monitoring:
Monitor the surgical site for signs of infection or complications
during the healing process.
Limited Mucoperiosteal Flap Design in Periradicular Surgery
Limited mucoperiosteal flaps are essential in periradicular surgery,
particularly for accessing the root surfaces while minimizing trauma to the
surrounding tissues. This flap design is characterized by specific incisions and
techniques that aim to enhance surgical visibility and access while promoting
better healing outcomes.
Limited Mucoperiosteal Flaps
Definition: Limited mucoperiosteal flaps involve
incisions that do not include marginal or interdental tissues, focusing on
preserving the integrity of the surrounding soft tissues.
Purpose: These flaps are designed to provide access to
the root surfaces for procedures such as apicoectomy, root resection, or
treatment of periapical lesions.
Types of Limited Mucoperiosteal Flaps
Submarginal Horizontal Incision
Description: A horizontal incision made in the
attached gingiva, avoiding the marginal gingiva.
Advantages: Preserves the marginal tissue, reducing
the risk of gingival recession and scarring.
Semilunar Flap
Description: A curved incision that begins in the
alveolar mucosa, dips into the attached gingiva, and returns to the
alveolar mucosa.
Advantages: Provides access while minimizing trauma
to the marginal tissue; however, it has poor healing potential and may
lead to scarring.
Scalloped (Ochsenbein-Luebke) Flap
Description: Similar to the rectangular flap but
with a scalloped horizontal incision in the attached gingiva.
Advantages: Follows the contour of the gingival
margins, preserving aesthetics but is also prone to delayed healing and
scarring.
Surgical Technique
Incision: The flap is initiated with a careful incision
in the attached gingiva, ensuring that the marginal tissue remains intact.
Reflection: The flap is gently reflected to expose the
underlying bone and root surfaces, allowing for the necessary surgical
procedures.
Irrigation and Closure: After the procedure, the area
should be well-irrigated to prevent infection, and the flap is
re-approximated and sutured in place.
Clinical Considerations
Healing Potential: Limited mucoperiosteal flaps
generally have better healing potential compared to full mucoperiosteal
flaps, as they preserve more of the surrounding tissue.
Aesthetic Outcomes: These flaps are particularly
beneficial in aesthetic zones, as they minimize the risk of visible scarring
and gingival recession.
Postoperative Care: Proper postoperative care,
including the use of ice packs and digital pressure on gauze, is essential
to control bleeding and promote healing.
Drawbacks
Limited Access: While these flaps minimize trauma, they
may provide limited access to the root surfaces, which can be a disadvantage
in complex cases.
Healing Complications: Although they generally promote
better healing, there is still a risk of complications such as delayed
healing or scarring, particularly with semilunar and scalloped designs.
Conclusion
Limited mucoperiosteal flap designs are valuable in periradicular surgery,
offering a balance between surgical access and preservation of surrounding
tissues. Understanding the various types of flaps and their applications can
significantly enhance the outcomes of endodontic surgical procedures. Proper
technique and postoperative care are crucial for achieving optimal healing and
aesthetic results.
The Henderson-Hasselbalch Equation
Biochemistry
By rearranging the above equation we arrive at the Henderson-Hasselbalch equation:
pH = pKa + log[A-]/[HA]
It should be obvious now that the pH of a solution of any acid (for which the equilibrium constant is known, and there are numerous tables with this information) can be calculated knowing the concentration of the acid, HA, and its conjugate base [A-].
At the point of the dissociation where the concentration of the conjugate base [A-] = to that of the acid [HA]:
pH = pKa + log[1]
The log of 1 = 0. Thus, at the mid-point of a titration of a weak acid:
pKa = pH
In other words, the term pKa is that pH at which an equivalent distribution of acid and conjugate base (or base and conjugate acid) exists in solution.
Dental Burs
Conservative DentistryDental BursDental burs are essential tools used in restorative dentistry for cutting,
shaping, and finishing tooth structure. The design and characteristics of burs
significantly influence their cutting efficiency, vibration, and overall
performance. Below is a detailed overview of the key features and considerations
related to dental burs.
1. Structure of BursA. Blades and Flutes
Blades: The cutting edges on a bur are uniformly
spaced, and the number of blades is always even.
Flutes: The spaces between the blades are referred to
as flutes. These flutes help in the removal of debris during cutting.
B. Cutting Action
Number of Blades:
Excavating Burs: Typically have 6-10 blades.
These burs are designed for efficient removal of tooth structure.
Finishing Burs: Have 12-40 blades,
providing a smoother finish to the tooth surface.
Cutting Efficiency:
A greater number of blades results in a smoother cutting action at
low speeds.
However, as the number of blades increases, the space between
subsequent blades decreases, which can reduce the overall cutting
efficiency.
2. Vibration and RPMA. Vibration
Cycles per Second: Vibrations over 1,300
cycles/second are generally imperceptible to patients.
Effect of Blade Number: Fewer blades on a bur tend to
produce greater vibrations during use.
RPM Impact: Higher RPM (revolutions per minute) results
in less amplitude and greater frequency of vibration, contributing to a
smoother cutting experience.
3. Rake AngleA. Definition
Rake Angle: The angle that the face of the blade makes
with a radial line drawn from the center of the bur to the blade.
B. Cutting Efficiency
Positive Rake Angle: Generally preferred for cutting
efficiency.
Radial Rake Angle: Intermediate efficiency.
Negative Rake Angle: Less efficient for cutting.
Clogging: Burs with a positive rake angle may
experience clogging due to debris accumulation.
4. Clearance AngleA. Definition
Clearance Angle: This angle provides necessary
clearance between the working edge and the cutting edge of the bur, allowing
for effective cutting without binding.
5. Run-OutA. Definition
Run-Out: Refers to the eccentricity or maximum
displacement of the bur head from its axis of rotation.
Acceptable Value: The average clinically acceptable
run-out is about 0.023 mm. Excessive run-out can lead to
uneven cutting and discomfort for the patient.
6. Load Applied by DentistA. Load Ranges
Low Speed: The load applied by the dentist typically
ranges from 100 to 1500 grams.
High Speed: The load is generally lower, ranging from 60
to 120 grams.
7. Diamond StonesA. Characteristics
Hardness: Diamond stones are the hardest and most
efficient abrasive tools available for removing tooth enamel.
Application: They are commonly used for cutting and
finishing procedures due to their superior cutting ability and durability.
CHARACTERISTICS AND CHEMISTRY OF HORMONES
Physiology
Each hormone in the body is unique. Each one is different in it's chemical composition, structure, and action. With respect to their chemical structure, hormones may be classified into three groups: amines, proteins, and steroids.
Amines- these simple hormones are structural variation of the amino acid tyrosine. This group includes thyroxine from the thyroid gland and epinephrine and norepinephrine from the adrenal medulla.
Proteins- these hormones are chains of amino acids. Insulin from the pancreas, growth hormone from the anterior pituitary gland, and calcitonin from the thyroid gland are all proteins. Short chains of amino acids are called peptides. Antidiuretic hormone and oxytocin, synthesized by the hypothalamus, are peptide hormones.
Steroids- cholesterol is the precursor for the steroid hormones, which include cortisol and aldosterone from the adrenal cortex, estrogen and progesterone from the ovaries, and testosterone from the testes.
Thyroid goitres
General Pathology
Thyroid goitres
A goitre is any enlargement of part or whole of the thyroid gland. There are two types:
1. Toxic goitre, i.e. goitre associated with thyrotoxicosis.
2. Non-toxic goitre, i.e. goitre associated with normal or reduced levels of thyroid hormones.
Toxic goitre
Graves disease
This is the most common cause of toxic goitre
Toxic multinodular goitre
This results from the development of hyperthyroidism in a multinodular goitre
Non-toxic goitres
Diffuse non-toxic goitre (simple goitre)
This diffuse enlargement of the thyroid gland is classified into:
Endemic goitre—due to iodine deficiency. Endemic goiter occurs in geographic areas (typically mountainous)) where the soil, water, and food supply contain little iodine. The term endemic is used when goiters are present in more than 10% of the population in a given region. With increasing availability of dietary iodine supplementation, the frequency and severity of endemic goiter have declined significantly. Sporadic goiter is less common than endemic goiter. The condition is more common in females than in males, with a peak incidence in puberty or young adult life, when there is an
increased physiologic demand for T4.
Sporadic goitre—caused by goitrogenic agents (substances that induce goitre formation) or familial in origin. Examples of goitrogenic agents include certain cabbage species, because of their thiourea content, and specific drugs or chemicals, such as iodide, paraminosalicylic acid and drugs used in the treatment of thyrotoxicosis. Familial cases show inherited autosomal recessive traits, which interfere with hormone synthesis via various enzyme pathways (these are dyshormonogenic goitres).
Hereditary enzymatic defects interfering with thyroid hormone synthesis (dyshormonogenetic goiter).
Physiological goitre—enlargement of the thyroid gland in females during puberty or pregnancy; the reason is unclear.
Multinodular goitre
This is the most common cause of thyroid enlargement and is seen particularly in the elderly (nearly all simple goitres eventually become multinodular). The exact aetiology is uncertain but it may represent an uneven responsiveness of various parts of the thyroid to fluctuating TSH levels over a period of many years.
Morphological features are:
• Irregular hyperplastic enlargement of the entire thyroid gland due to the development of wellcircumscribed nodules of varying size.
• Larger nodules filled with brown, gelatinous colloid; consequently, it is often termed multinodular colloid goitres.
Clinical features
- A large neck mass, goiters may also cause airway obstruction, dysphagia, and compression of large vessels in the neck and upper thorax.
- A hyperfunctioning ("toxic") nodule may develop within a long-standing goiter, resulting in hyperthyroidism. This condition is not accompanied by the infiltrative ophthalmopathy and dermopathy.
- Less commonly, there may be hypothyroidism.