NEET MDS Synopsis
Types of Removable Orthodontic Appliances
OrthodonticsTypes of Removable Orthodontic Appliances
Functional Appliances:
Purpose: Designed to modify the growth of the jaw
and improve the relationship between the upper and lower teeth.
Examples:
Bionator: Encourages forward positioning of the
mandible.
Frankel Appliance: Used to modify the position
of the dental arches and improve facial aesthetics.
Retainers:
Purpose: Used to maintain the position of teeth
after orthodontic treatment.
Types:
Hawley Retainer: A custom-made acrylic plate
with a wire framework that holds the teeth in position.
Essix Retainer: A clear, plastic retainer that
fits over the teeth, providing a more aesthetic option.
Space Maintainers:
Purpose: Used to hold space for permanent teeth
when primary teeth are lost prematurely.
Types:
Band and Loop: A metal band placed on an
adjacent tooth with a loop extending into the space.
Distal Shoe: A space maintainer used in the
lower arch to maintain space for the first molar.
Aligners:
Purpose: Clear plastic trays that gradually move
teeth into the desired position.
Examples:
Invisalign: A popular brand of clear aligners
that uses a series of custom-made trays to achieve tooth movement.
Expansion Appliances:
Purpose: Used to widen the dental arch,
particularly in cases of crossbite or narrow arches.
Examples:
Rapid Palatal Expander (RPE): A device that
applies pressure to the upper molars to widen the maxilla.
Components of Removable Orthodontic Appliances
Baseplate: The foundation of the appliance, usually
made of acrylic, which holds the other components in place.
Active Components: Springs, screws, or other mechanisms
that exert forces on the teeth to achieve movement.
Retention Components: Clasps or other features that
help keep the appliance securely in place during use.
Adjustable Parts: Some appliances may have adjustable
components to fine-tune the force applied to the teeth.
Indications for Use
Correction of Malocclusions: Removable appliances can
be used to address various types of malocclusions, including crowding,
spacing, and crossbites.
Space Maintenance: To hold space for permanent teeth
when primary teeth are lost prematurely.
Tooth Movement: To move teeth into desired positions,
particularly in growing patients.
Retention: To maintain the position of teeth after
orthodontic treatment.
Jaw Relationship Modification: To influence the growth
of the jaw and improve the relationship between the dental arches.
Advantages of Removable Orthodontic Appliances
Patient Compliance: Patients can remove the appliance
for eating, brushing, and social situations, which can improve compliance.
Hygiene: Easier to clean compared to fixed appliances,
reducing the risk of plaque accumulation and dental caries.
Flexibility: Can be adjusted or modified as treatment
progresses.
Less Discomfort: Generally, removable appliances are
less uncomfortable than fixed appliances, especially during initial use.
Aesthetic Options: Clear aligners and other aesthetic
appliances can be more visually appealing to patients.
Disadvantages of Removable Orthodontic Appliances
Compliance Dependent: The effectiveness of removable
appliances relies heavily on patient compliance; if not worn as prescribed,
treatment may be delayed or ineffective.
Limited Force Application: They may not be suitable for
complex tooth movements or significant skeletal changes.
Adjustment Period: Some patients may experience
discomfort or difficulty speaking initially.
Dental implications of antiepileptic drugs:
Pharmacology
Dental implications of these drugs:
1. Adverse effects: gingival hyperplasia (phenytoin), osteomalacia (phenytoin, Phenobarbital), blood dyscrasias (all but rare)
2. Drug interactions: additive CNS depression (anesthetics, anxiolytics, opioid analgesics), induction of hepatic microsomal enzymes (phenytoin, Phenobarbital, carbamazepine), plasma protein binding (phenytoin and valproic acid)
3. Seizure susceptibility: stress can → seizures
Excision of Lesions Involving the Jaw Bone
General SurgeryExcision of Lesions Involving the Jaw Bone
When excising lesions involving the jaw bone, various terminologies are used
to describe the specific techniques and outcomes of the procedures.
1. Enucleation
Enucleation refers to the separation of a
lesion from the bone while preserving bone continuity. This is achieved by
removing the lesion along an apparent tissue or cleavage plane, which is
often defined by an encapsulating or circumscribing connective tissue
envelope derived from the lesion or surrounding bone.
Key Characteristics:
The lesion is contained within a defined envelope.
Bone continuity is maintained post-excision.
2. Curettage
Curettage involves the removal of a lesion
from the bone by scraping, particularly when the lesion is friable or lacks
an intact encapsulating tissue envelope. This technique may result in the
removal of some surrounding bone.
Key Characteristics:
Indicates the inability to separate the lesion along a distinct
tissue plane.
May involve an inexact or immeasurable thickness of surrounding
bone.
If a measurable margin of bone is removed, it is termed "resection
without continuity defect."
3. Marsupialization
Marsupialization is a surgical procedure
that involves the exteriorization of a lesion by removing overlying tissue
to expose its internal surface. This is done by excising a portion of the
lesion bordering the oral cavity or another body cavity.
Key Characteristics:
Multicompartmented lesions are rendered unicompartmental.
The lesion is clinically cystic, and the excised tissue may include
bone and/or overlying mucosa.
4. Resection Without Continuity Defect
This term describes the excision of a
lesion along with a measurable perimeter of investing bone, without
interrupting bone continuity. The anatomical relationship allows for the
removal of the lesion while preserving the integrity of the bone.
Key Characteristics:
Bone continuity is maintained.
Adjacent soft tissue may be included in the resection.
5. Resection With Continuity Defect
This involves the excision of a lesion that
results in a defect in the continuity of the bone. This is often associated
with more extensive resections.
Key Characteristics:
Bone continuity is interrupted.
May require reconstruction or other interventions to restore
function.
6. Disarticulation
Disarticulation is a special form of
resection that involves the temporomandibular joint (TMJ) and results in a
continuity defect.
Key Characteristics:
Involves the removal of the joint and associated structures.
Results in loss of continuity in the jaw structure.
7. Recontouring
Recontouring refers to the surgical
reduction of the size and/or shape of the surface of a bony lesion or bone
part. The goal is to reshape the bone to conform to the adjacent normal bone
surface or to achieve an aesthetic result.
Key Characteristics:
May involve lesions such as bone hyperplasia, torus, or exostosis.
Can be performed with or without complete eradication of the lesion
(e.g., fibrous dysplasia).
DIPHTHERIA
General Pathology
DIPHTHERIA
An acute, contagious disease caused by Corynebacterium diphtheriae, characterized by the formation of a fibrinous pseudomembrane, usually on the respiratory mucosa, and by myocardial and neural tissue damage secondary to an exotoxin.
Cutaneous diphtheria (infection of the skin) can occur when any disruption of the integument is colonized by C. diphtheriae. Lacerations, abrasions, ulcers, burns, and other wounds are potential reservoirs of the organism. Skin carriage of C. diphtheriae is also a silent reservoir of infection.
Pathology
C. diphtheriae may produce exotoxins lethal to the adjacent host cells. Occasionally, the primary site is the skin or mucosa elsewhere. The exotoxin, carried by the blood, also damages cells in distant organs, creating pathologic lesions in the respiratory passages, oropharynx, myocardium, nervous system, and kidneys.
The myocardium may show fatty degeneration or fibrosis. Degenerative changes in cranial or peripheral nerves occur chiefly in the motor fibers
In severe cases, anterior horn cells and anterior and posterior nerve roots may show damage proportional to the duration of infection before antitoxin is given. The kidneys may show a reversible interstitial nephritis with extensive cellular infiltration.
The diphtheria bacillus first destroys a layer of superficial epithelium, usually in patches, and the resulting exudate coagulates to form a grayish pseudomembrane containing bacteria, fibrin, leukocytes, and necrotic epithelial cells. However, the areas of bacterial multiplication and toxin absorption are wider and deeper than indicated by the size of the membrane formed in the wake of the spreading infection.
TetricEvoFlow
PedodonticsTetricEvoFlow
TetricEvoFlow is an advanced nano-optimized flowable composite developed by
Ivoclar Vivadent, designed to enhance dental restorations with its superior
properties. As the successor to Tetric Flow, it offers several key benefits:
Optimum Surface Affinity: TetricEvoFlow exhibits
excellent adhesion to tooth structures, ensuring a reliable bond and
minimizing the risk of microleakage.
Penetration into Difficult Areas: Its flowable nature
allows it to reach and fill even the most challenging areas, making it ideal
for intricate restorations.
Versatile Use: This composite can serve as an initial
layer beneath medium-viscosity composites, such as TetricEvoCeram, providing
a strong foundation for layered restorations.
Stability for Class V Restorations: TetricEvoFlow
maintains its stability when required, making it particularly suitable for
Class V restorations, where durability and aesthetics are crucial.
Extended Applications: In addition to its use in
restorations, TetricEvoFlow is effective for extended fissure sealing and
can be utilized in adhesive cementation techniques.
The Middle Ear
AnatomyThe Middle Ear
This part of the ear is in a narrow cavity in the petrous part of the temporal bone.
It contains air, three auditory ossicles, a nerve and two small muscles.
The middle ear is separated from the external acoustic meatus by the tympanic membrane.
This cavity includes the tympanic cavity proper, the space directly internal to the tympanic membrane, and the epitympanic recess, the space superior to it.
The middle ear is connected anteriorly with the nasopharynx by the auditory tube.
Posterosuperiorly, the tympanic cavity connects with the mastoid cells through the aditus ad antrum (mastoid antrum).
The tympanic cavity is lined with mucous membrane that is continuous with the mucous membrane of the auditory tube, mastoid cells, and aditus ad antrum.
Contents of the Tympanic Cavity or Middle Ear
This cavity contains the auditory ossicles (malleus, incus and stapes); the stapedius and tensor tympani muscles; the chorda tympani nerve (a branch of the facial nerve, CN VII); and the tympanic plexus of nerves.
DIURETICS
Pharmacology
DIURETICS
Specific Therapeutic Objective
Clinical State(s)
Drug(s) (Class)
Draw fluid from tissue to vascular space reduce tissue edema
Cerebral edema
glaucoma
Mannitol (Osmotic)
Glucose (Osmotic)
Glycerin (Osmotic)
Decrease renal swelling
expand tubular volume
Renal shutdown
Glucose (Osmotic)
Mannitol (Osmotic)
Modest and/or sustained decrease in venous hydrostatic pressure
Congestive heart failure
Hepatic cirrhosis
Udder edema
Hydrochlorothiazide (thiazide)
Chlorothiazide (thiazide)
Aggressive and/or short-term decrease in venous hydrostatic pressure
Congestive heart failure
Hepatic cirrhosis
Udder edema
Furosemide (loop)
Inhibit aldosterone action
Hepatic cirrhosis
Congestive heart failure
triamterene (K+ sparing)
spironolactone (K+ sparing - competitive)
Reduce potassium wasting 2o to other diuretic
Hepatic cirrhosis
Congestive heart failure
triamterene (K+ sparing)
spironolactone (K+ sparing - competitive)
Inhibit ADH action
Inappropriate ADH secretion
lithium (aquaretic)
demeclocycline (aquaretic
Increase calcium secretion
Malignant hypercalcemia
Paraneoplastic
Hypervitaminosis D
Furosemide (loop)
Reduce urine output
Diabetes insidpidus
Hydrochlorothiazide (thiazide)
Chlorothiazide (thiazide)
Urine alkalinization
Various
Carbonic anhydrase inhibitors
Eczematous Dermatitis
General Pathology
Eczematous Dermatitis
Eczematous dermatitis includes a large category of skin lesions characterized by severe pruritus and distinctive gross and microscopic features.
- type I hypersensitivity is involved with atopic dermatitis in patients who have an allergic history.
- type IV hypersensitivity is involved in contact dermatitis (poison ivy).
- acute eczematous dermatitis is characterized by a weeping, pruritic rash, while a chronic eczematous dermatitis presents with dry, scaly, plaque-like thickening of the skin, a process called lichenification.