NEET MDS Synopsis
SALIVARY GLANDS
Dental Anatomy
HISTOLOGY OF SALIVARY GLANDS
Parotid: so-called watery serous saliva rich in amylase
Submandibular gland: more mucinous
Sublingual: viscous saliva
Parotid Gland: The parotid is a serous secreting gland.
There are also fat cells in the parotid.
Submandibular Gland
This gland is serous and mucous secreting.
There are serous demilunes
This gland is more serous than mucous
Also fat cells
Sublingual Gland
Serous and mucous secreting
Serous cells in the form of demilunes on the mucous acini.
more mucous than serous cells
Minor Salivary Glands
Minor salivary glands are not found within gingiva and anterior part of the hard palate
Serous minor glands=von Ebner below the sulci of the circumvallate and folliate papillae of the tongue; palatine, glossopalatine glands are pure mucus; some lingual glands are also pure mucus
Functions
Protection: lubricant (glycoprotein); barrier against noxious stimuli; microbial toxins and minor traumas; washing non-adherent and acellular debris; calcium-binding proteins: formation of salivary pellicle
Buffering: bacteria require specific pH conditions; plaque microorganisms produce acids from sugars; phosphate ions and bicarbonate
Digestion: neutralizes esophageal contents, dilutes gastric chyme; forms food bolus; brakes starch
Taste: permits recognition of noxious substances; protein gustin necessary for growth and maturation of taste buds
Antimicrobial: lysozyme hydrolyzes cell walls of some bacteria; lactoferrin binds free iron and deprives bacteria of this essential element; IgA agglutinates microorganisms
Maintenance of tooth integrity: calcium and phosphate ions; ionic exchange with tooth surface
Tissue repair: bleeding time of oral tissues shorter than other tissues; resulting clot less solid than normal; remineralization
Characteristics of Immunoglobulin subclasses
General Pathology
Characteristics of Immunoglobulin subclasses
I. Ig G:
(i) Predominant portion (80%) of Ig.
(ii) Molecular weight 150, 000
(iii) Sedimentation coefficient of 7S.
(iv) Crosses placental barrier and to extra cellular fluid.
(v) Mostly neutralising effect. May be complement fixing.
(vi) Half life of 23 days.
2.IgM :
(i) Pentamer of Ig.
(ii) Molecular weight 900, 000
(iii) 19S.
(iv) More effective complement fixation and cells lysis
(v) Earliest to be produced in infections.
(vi) Does not cross placental barrier.
(vii) Halflife of 5 days.
3. Ig A :
Secretory antibody. Found in intestinal, respiratory secretions tears, saliva and urine also.
Secreted usually as a dinner with secretory piece.
Mol. weight variable (160,000+)
7 S to 14 S.
Half life of 6 days.
4.Ig D :
Found in traces.
7 S.
Does not cross placenta.
5. Ig E
Normally not traceable
7-8 S (MoL weight 200,000)
Cytophilic antibody, responsible for some hypersensitivity states,
Indications for Rigid Osteosynthesis
Oral Maxillofacial Surgery
- Fractures in an edentulous part of the body of the mandible.
-Concomitant fractures of the body and condyle when early mobilization is indicated.
- Continuity defects.
- Fractures in which non-union or malunion has occurred.
- Patients in whom intermaxillary fixation is contraindicated.
- Fractures associated with closed head injury.
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.
Ligaments of the Joint
AnatomyLigaments of the Joint
The fibrous capsule is thickened laterally to form the lateral (temporomandibular) ligament. It reinforces the lateral part of this capsule.
The base of this triangular ligament is attached to the zygomatic process of the temporal bone and the articular tubercle.
Its apex is fixed to the lateral side of the neck of the mandible.
Two other ligaments connect the mandible to the cranium but neither provides much strength.
The stylomandibular ligament is a thickened band of deep cervical fascia.
It runs from the styloid process of the temporal bone to the angle of the mandible and separates the parotid and submandibular salivary glands.
The sphenomandibular ligament is a long membranous band that lies medial to the joint.
This ligament runs from the spine of the sphenoid bone to the lingula on the medial aspect of the mandible.
Space Maintainers
PedodonticsSpace Maintainers: A fixed or removable appliance designed
to maintain the space left by a prematurely lost tooth, ensuring proper
alignment and positioning of the permanent dentition.
Importance of Primary Teeth
Primary teeth serve as the best space maintainers for the permanent
dentition. Their presence is crucial for guiding the eruption of permanent
teeth and maintaining arch integrity.
Consequences of Space Loss
When a tooth is lost prematurely, the space can change significantly within a
six-month period, leading to several complications:
Loss of Arch Length: This can result in crowding of the
permanent dentition.
Impaction of Permanent Teeth: Teeth may become impacted
if there is insufficient space for their eruption.
Esthetic Problems: Loss of space can lead to visible
gaps or misalignment, affecting a child's smile.
Malocclusion: Improper alignment of teeth can lead to
functional issues and bite problems.
Indications for Space Maintainers
Space maintainers are indicated in the following situations:
If the space shows signs of closing.
If using a space maintainer will simplify future orthodontic treatment.
If treatment for malocclusion is not indicated at a later date.
When the space needs to be maintained for two years or more.
To prevent supra-eruption of opposing teeth.
To improve the masticatory system and restore dental health.
Contraindications for Space Maintainers
Space maintainers should not be used in the following situations:
If radiographs show that the succedaneous tooth will erupt soon.
If one-third of the root of the succedaneous tooth is already calcified.
When the space left is greater than what is needed for the permanent
tooth, as indicated radiographically.
If the space shows no signs of closing.
When the succedaneous tooth is absent.
Classification of Space Maintainers
Space maintainers can be classified into two main categories:
1. Fixed Space Maintainers
These are permanently attached to the teeth and cannot be removed
by the patient. Examples include band and loop space maintainers.
Common types include:
Band and Loop Space Maintainer:
A metal band is placed around an adjacent tooth, and a wire loop
extends into the space of the missing tooth. This is commonly used
for maintaining space after the loss of a primary molar.
Crown and Loop Space Maintainer:
Similar to the band and loop, but a crown is placed on the
adjacent tooth instead of a band. This is used when the adjacent
tooth requires a crown.
Distal Shoe Space Maintainer:
This is used when a primary second molar is lost before the
eruption of the permanent first molar. It consists of a metal band
on the first molar with a metal extension (shoe) that guides the
eruption of the permanent molar.
Transpalatal Arch:
A fixed appliance that connects the maxillary molars across the
palate. It is used to maintain space and prevent molar movement.
Nance Appliance:
Similar to the transpalatal arch, but it has a small acrylic
button that rests against the anterior palate. It is used to
maintain space in the upper arch.
2. Removable Space Maintainers
These can be taken out by the patient and are typically used when more
than one tooth is lost. They can also serve to replace occlusal function and
improve esthetics.
Common types include:
Removable Partial Denture:
A prosthetic device that replaces one or more missing teeth and
can be removed by the patient. It can help maintain space and
restore function and esthetics.
Acrylic Space Maintainer:
A simple acrylic appliance that can be used to maintain space.
It is often used in cases where esthetics are a concern.
Functional Space Maintainers:
These are designed to provide occlusal function while
maintaining space. They may include components that allow for
chewing and speaking.
Types of Removable Space Maintainers
Non-functional: Typically used when more than one tooth
is lost.
Functional: Designed to provide occlusal function.
Advantages of Removable Space Maintainers
Easy to clean and maintain proper oral hygiene.
Maintains vertical dimension.
Can be worn part-time, allowing circulation of blood to soft tissues.
Creates room for permanent teeth.
Helps prevent the development of tongue thrust habits into the
extraction space.
Disadvantages of Removable Space Maintainers
May be lost or broken by the patient.
Uncooperative patients may not wear the appliance.
Lateral jaw growth may be restricted if clasps are incorporated.
May cause irritation of the underlying soft tissues.
Chronic hepatitis
General Pathology
Chronic hepatitis
Chronic hepatitis occurs in 5%-10% of HBV infections and in well over 50% of HCV; it does not occur in HAV. Most chronic disease is due to chronic persistent hepatitis. The chronic form is more likely to occur in the very old or very young, in males, in immunocompromised hosts, in Down's syndrome, and in dialysis patients.
a. Chronic persistent hepatitis is a benign, self-limited disease with a prolonged recovery. Patients are asymptomatic except for elevated transaminases.
b. Chronic active hepatitis features chronic inflammation with hepatocyte destruction, resulting in cirrhosis and liver failure.
(1) Etiology. HBV, HCV, HDV, drug toxicity, Wilson's disease, alcohol, a,-antitrypsin deficiency, and autoimmune hepatitis are common etiologies.
(2) Clinical features may include fatigue, fever, malaise, anorexia, and elevated liver function tests.
(3) Diagnosis is made by liver biopsy.
8. Carrier state for HBV and HCV may be either asymptomatic or with liver disease; in the latter case, the patient has elevate transaminases.
a. Incidence is most common in immunodeficient, drug addicted, Down's syndrome, and dialysis patients.
b. Pathology of asymptomatic carriers shows "ground-glass"" hepatocytes with finely granular eosinophilic cytoplasm.
Nephritic syndrome
General Pathology
Nephritic syndrome
Characterized by inflammatory rupture of the glomerular capillaries, leaking blood into the urinary space.
Classic presentation: poststreptococcal glomerulonephritis. It occurs after a group A, β–hemolytic Streptococcus infection (e.g., strep throat.)
Caused by autoantibodies forming immune complexes in the glomerulus.
Clinical manifestations:
oliguria, hematuria, hypertension, edema, and azotemia (increased concentrations of serum urea nitrogen
and creatine).