NEET MDS Synopsis
The Lateral Wall of the Orbit
AnatomyThe Lateral Wall of the Orbit
This wall is thick, particularly its posterior part, which separates the orbit from the middle cranial fossa.
The lateral wall is formed by the frontal process of the zygomatic bone and the greater wing of the sphenoid bone.
Anteriorly, the lateral wall lies between the orbit and the temporal fossa.
The lateral wall is partially separated from the roof by the superior orbital fissure.
INNERVATION OF THE DENTIN-PULP COMPLEX
Dental Anatomy
INNERVATION OF THE DENTIN-PULP COMPLEX
Dentine Pulp
Dentin
Nerve Fibre Bundle
Nerve fibres
The nerve bundles entering the tooth pulp consist principally of sensory afferent fibers from the trigeminal nerve and sympathetic branches from the superior cervical ganglion. There are non-myelinated (C fibers) and myelinated (less than non, A-delta, A-beta) fibers. Some nerve endings terminate on or in association with the odontoblasts and others in the predentinal tubules of the crown. Few fibers are found among odontoblasts of the root.
In the cell-free zone one can find the plexus of Raschkow.
Nervous System - Infections
General Pathology
Bacterial meningitis (pyogenic, suppurative infections)
1. Common causes include:
a. Escherichia coli in newborns.
b. Haemophilus influenzae in infants and children.
c. Neisseria meningitides in young adults.
d. Streptococcus pneumoniae and Listeria monocytogenes in older adults.
Clinical findings include severe headache, irritability, fever, and a stiff neck.
a. A spinal tap shows CSF fluid that is cloudy or purulent and is under increased pressure. There is also an increase in protein and a decrease in glucose levels.
3. Can be fatal if left untreated.
Nail Biting Habits
OrthodonticsNail Biting Habits
Nail biting, also known as onychophagia, is one of the most
common habits observed in children and can persist into adulthood. It is often
associated with internal tension, anxiety, or stress. Understanding the
etiology, clinical features, and management strategies for nail biting is
essential for addressing this habit effectively.
Etiology
Emotional Problems:
Persistent nail biting may indicate underlying emotional issues,
such as anxiety, stress, or tension. It can serve as a coping mechanism
for dealing with these feelings.
Psychosomatic Factors:
Nail biting can be a psychosomatic response to stress or emotional
discomfort, manifesting physically as a way to relieve tension.
Successor of Thumb Sucking:
For some children, nail biting may develop as a successor to thumb
sucking, particularly as they transition from one habit to another.
Clinical Features
Dental Effects:
Crowding: Nail biting can contribute to dental
crowding, particularly if the habit leads to changes in the position of
the teeth.
Rotation: Teeth may become rotated or misaligned
due to the pressure exerted during nail biting.
Alteration of Incisal Edges: The incisal edges of
the anterior teeth may become worn down or altered due to repeated
contact with the nails.
Soft Tissue Changes:
Inflammation of Nail Bed: Chronic nail biting can
lead to inflammation and infection of the nail bed, resulting in
redness, swelling, and discomfort.
Management
Awareness:
The first step in management is to make the patient aware of their
nail biting habit. Understanding the habit's impact on their health and
appearance can motivate change.
Addressing Emotional Factors:
It is important to identify and treat any underlying emotional
issues contributing to the habit. This may involve counseling or therapy
to help the individual cope with stress and anxiety.
Encouraging Outdoor Activities:
Engaging in outdoor activities and physical exercise can help reduce
tension and provide a positive outlet for stress, potentially decreasing
the urge to bite nails.
Behavioral Modifications:
Nail Polish: Applying a bitter-tasting nail polish
can deter nail biting by making the nails unpalatable.
Light Cotton Mittens: Wearing mittens or gloves can
serve as a physical reminder to avoid nail biting and can help break the
habit.
Positive Reinforcement:
Encouraging and rewarding the individual for not biting their nails
can help reinforce positive behavior and motivate them to stop.
Antiemetics
Pharmacology
Antiemetics
Antiemetic drugs are generally more effective in prophylaxis than treatment. Most antiemetic agents relieve nausea and vomiting by acting on the vomiting centre, dopamine receptors, chemoreceptors trigger zone (CTZ), cerebral cortex, vestibular apparatus, or a combination of these.
Drugs used in the treatment of nausea and vomiting belong to several different groups. These include:
1. Phenothiazines, such as chlorpromazine, act on CTZ and vomiting centre, block dopamine receptors, are effective in preventing or treating nausea and vomiting induced by drugs, radiation therapy, surgery and most other stimuli (e.g. pregnancy).
They are generally ineffective in motion sickness.
Droperidol had been used most often for sedation in endoscopy and surgery, usually in combination with opioids or benzodiazepines
2. Antihistamines such as promethazine and Dimenhyrinate are especially effective in prevention and treatment of motion.
3. Metoclopramide has both central and peripheral antiemetic effects. Centrally, it antagonizes the action of dopamine. Peripherally metoclopramide stimulates the release of acetylcholine, which in turn, increases the rate of gastric. It has similar indications to those of chlorpromazine.
4. Scopolamine, an anticholinergic drug, is very effective in reliving nausea & vomiting associated with motion sickness.
5. Ondansetron, a serotonin antagonist, is effective in controlling chemical-induced vomiting and nausea such those induced by anticancer drugs.
6. Benzodiazepines: The antiemetic potency of lorazepam and alprazolam is low. Their beneficial effects may be due to their sedative, anxiolytic, and amnesic properties
Immunofluorescence
General MicrobiologyImmunofluorescence
This is precipitation or complement fixation tests. The technique can detect proteins at concentrations of around 1 µg protein per ml body fluid. Major disadvantage with this technique is frequent occurrence of nonspecific fluorescence in the tissues and other material.
The fluorescent dyes commonly used are fluorescein isothocyanate (FITC). These dyes exhibit fluorescence by absorbing UV light between 290 and 495 nm and emitting longer wavelength coloured light of 525 nm which gives shining appearance (fluorescence) to protein labelled with dye. Blue green (apple green) fluorescence is seen with FITC and orange red with rhodamine.
Enzyme Immunoassays
These are commonly called as enzyme linked immunosorbent assays or EL1SA. It is a simple and versatile technique which is as sensitive as radioimmunoassays. It is now the
technique for the detection of antigens, antibodies, hormones, toxins and viruses.
Identification of organisms by immunofluorescence
Type of agent Examples
Bacterial Neisseria gonorrhoeae, H. influenzae ,Strept pyogenes, Treponema pallidum
Viral Herpesvirus, Rabiesvirus, Epstein-Barr virus
Mycotic Candida albicans
Enzymatic activity results in a colour change which can be assessed visibly or quantified in a simple spectrophotometer.
IONIZATION OF WATER, WEAK ACIDS AND WEAK BASES
Biochemistry
IONIZATION OF WATER, WEAK ACIDS AND WEAK BASES
The ionization of water can be described by an equilibrium constant. When weak acids or weak bases are dissolved in water, they can contribute H+ by ionizing (if acids) or consume H+ by being protonated (if bases). These processes are also governed by equilibrium constants
Water molecules have a slight tendency to undergo reversible ionization to yield a hydrogen ion and a hydroxide ion :
H2O = H+ + OH−
The position of equilibrium of any chemical reaction is given by its equilibrium constant. For the general reaction,
A+B = C + D
Applegate's Rules
Prosthodontics→ Following rules should be considered to classify partially edentulous
arches, based on Kennedy's classification.
Rule 1:
→ Classification should follow, rather than precede extraction, that might
alter the original classification.
Rule 2:
→ If 3rd molar is missing and not to be replaced, it is not
considered in classification.
Rule 3:
→ If the 3rd molar is present and is to be used as an abutment, it
is considered in classification.
Rule 4:
→ If second molar is missing and is not to be replaced, it is not
considered in classification.
Rule 5:
→ The most posterior edentulous area or areas always determine the
classification.
Rule 6:
→ Edentulous areas other than those, which determine the classification are
referred as modification spaces and are designated by their number.
Rule 7:
→ The extent of modification is not considered, only the number of additional
edentulous areas are taken into consideration (i.e. no. of teeth missing in
modification spaces are not considered, only no. of additional edentulous spaces
are considered).
Rule 8:
→ There can be no modification areas in class IV.