NEET MDS Synopsis
Gastric acid neutralizers (antacids)
Pharmacology
Gastric acid neutralizers (antacids)
Antacids act primarily in the stomach and are used to prevent and treat peptic ulcer. They are also used in the treatment of Reflux esophagitis and Gastritis.
Mechanism of action:
Antacids are alkaline substances (weak bases) that neutralize gastric acid (hydrochloric acid) they react with hydrochloric acid in the stomach to produce neutral or less acidic or poorly absorbed products and raise the pH of stomach secretion.
Antacids are divided into systemic and non-systemic.
• Systemic antacids (e.g. sodium bicarbonate) are highly absorbed into systemic circulation and enter body fluids. Therefore, they may alter acid–base balance. They can be used in the treatment of metabolic acidosis.
Non-systemic: they do not alter acid–base balance significantly, because they are not well-absorbed into the systemic circulation. They are used as gastric antacids; and include:
• Magnesium compounds such as magnesium hydroxide and magnesium sulphate MgS2O3. They have relatively high neutralizing capacity, rapid onset of action, however, they may cause diarrhoea and hypermagnesemia.
• Aluminium compounds such as aluminium hydroxide. Generally, these have low neutralizing capacity, slow onset of action but long duration of action. They may cause constipation.
• Calcium compounds such as. These are highly effective and have a rapid onset of action but may cause hypersecretion of acid (acid - rebound) and milk-alkali syndrome (hence rarely used in peptic ulcer disease).
Therefore, the most commonly used antacids are mixtures of aluminium hydroxide and magnesium hydroxide .
Twin Block appliance
OrthodonticsTwin Block appliance is a removable functional orthodontic
device designed to correct malocclusion by positioning the lower jaw forward. It
consists of two interlocking bite blocks, one for the upper jaw and one for the
lower jaw, which work together to align the teeth and improve jaw relationships.
Features of the Twin Block Appliance
Design: The Twin Block consists of two separate
components that fit over the upper and lower teeth, promoting forward
movement of the lower jaw.
Functionality: It utilizes the natural bite forces to
gradually shift the lower jaw into a more favorable position, addressing
issues like overbites and jaw misalignments.
Material: Typically made from acrylic, the appliance is
custom-fitted to ensure comfort and effectiveness during treatment.
Treatment Process
Initial Consultation:
A comprehensive evaluation is conducted, including X-rays and
impressions to assess the alignment of teeth and jaws.
Fitting the Appliance:
Once ready, the Twin Block is fitted and adjusted to the patient's
mouth. Initial discomfort may occur but usually subsides quickly.
Active Treatment Phase:
Patients typically wear the appliance full-time for about 12 to 18
months, with regular check-ups for adjustments.
Retention Phase:
After active treatment, a retainer may be required to maintain the
new jaw position while the bone stabilizes.
Benefits of the Twin Block Appliance
Non-Surgical Solution: Offers a less invasive
alternative to surgical options for correcting jaw misalignments.
Improved Functionality: Enhances chewing, speaking, and
overall jaw function by aligning the upper and lower jaws.
Facial Aesthetics: Contributes to a more balanced facial
profile, boosting self-esteem and confidence.
Faster Results: Compared to traditional braces, the Twin
Block can provide quicker corrections, especially in growing patients.
Care and Maintenance
Oral Hygiene: Patients should maintain good oral hygiene
by brushing and flossing regularly, especially around the appliance.
Food Restrictions: Avoid hard, sticky, or chewy foods
that could damage the appliance.
Regular Check-Ups: Attend scheduled appointments to
ensure the appliance is functioning correctly and to make necessary
adjustments.
The Cheeks
AnatomyThe Cheeks
The cheeks (L. buccae) form the lateral wall of the vestibule of the oral cavity.
They have essentially the same structure as the lips with which they are continuous.
The principal muscular component of the cheeks is the buccinator muscle.
Superficial to the fascia covering this muscle is the buccal fatpad that gives cheeks their rounded contour, especially in infants.
The lips and cheeks act as a functional unit (e.g. during sucking, blowing, eating, etc.).
They act as an oral sphincter in pushing food from the vestibule to the oral cavity proper.
The tongue and buccinator muscle keep the food between the molar teeth during chewing.
Sensory Nerves of the Cheeks
These are branches of the maxillary and mandibular nerves.
They supply the skin of the cheeks and the mucous membrane lining the cheeks.
German measles
General Pathology
German measles (rubella)
- sometimes called "three day measles".
- incubation 14-21 days; infectious 7 days before the rash and 14 days after the onset of the rash.
- in adults, rubella present with fever, headache, and painful postauricular Lymphadenopathy 1 to 2 days prior to the onset of rash, while in children, the rash is usually the first sign.
- rash (vasculitis) consists of tiny red to pink macules (not raised) that begins on the head and spreads downwards and disappears over the ensuing 1-3 days; rash tends to become confluent.
- 1/3rd of young women develop arthritis due to immune-complexes.
- splenomegaly (50%)
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
STREPTOCOCCAL INFECTIONS
General Pathology
STREPTOCOCCAL INFECTIONS
Most streptococci are normal flora of oropharynx
Group A streptococci: Str. pyogenes
Group B streptococci: Str. agalactiae
Str. pneumoniae
Strep viridans group
Group D: Enterococcus (lately Strep. Fecalis and E. fecium), causes urinary tract infections,
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
Submasseteric Space Infection
Oral and Maxillofacial SurgerySubmasseteric Space Infection
Submasseteric space infection refers to an infection that
occurs in the submasseteric space, which is located beneath the masseter muscle.
This space is clinically significant in the context of dental infections,
particularly those arising from the lower third molars (wisdom teeth) or other
odontogenic sources. Understanding the anatomy and potential spread of
infections in this area is crucial for effective diagnosis and management.
Anatomy of the Submasseteric Space
Location:
The submasseteric space is situated beneath the masseter muscle,
which is a major muscle involved in mastication (chewing).
This space is bordered superiorly by the masseter muscle and
inferiorly by the lower border of the ramus of the mandible.
Boundaries:
Inferior Boundary: The extension of an abscess or
infection inferiorly is limited by the firm attachment of the masseter
muscle to the lower border of the ramus of the mandible. This attachment
creates a barrier that can restrict the spread of infection downward.
Anterior Boundary: The forward spread of infection
beyond the anterior border of the ramus is restricted by the anterior
tail of the tendon of the temporalis muscle, which inserts into the
anterior border of the ramus. This anatomical feature helps to contain
infections within the submasseteric space.
Posterior Boundary: The posterior limit of the
submasseteric space is generally defined by the posterior border of the
ramus of the mandible.
Clinical Implications
Sources of Infection:
Infections in the submasseteric space often arise from odontogenic
sources, such as:
Pericoronitis associated with impacted lower third molars.
Dental abscesses from other teeth in the mandible.
Periodontal infections.
Symptoms:
Patients with submasseteric space infections may present with:
Swelling and tenderness in the area of the masseter muscle.
Limited mouth opening (trismus) due to muscle spasm or swelling.
Pain that may radiate to the ear or temporomandibular joint
(TMJ).
Fever and systemic signs of infection in more severe cases.
Diagnosis:
Diagnosis is typically made through clinical examination and imaging
studies, such as panoramic radiographs or CT scans, to assess the extent
of the infection and its relationship to surrounding structures.
Management:
Treatment of submasseteric space infections usually involves:
Antibiotic Therapy: Broad-spectrum antibiotics
are often initiated to control the infection.
Surgical Intervention: Drainage of the abscess
may be necessary, especially if there is significant swelling or if
the patient is not responding to conservative management. Incision
and drainage can be performed intraorally or extraorally, depending
on the extent of the infection.
Management of the Source: Addressing the
underlying dental issue, such as extraction of an impacted tooth or
treatment of a dental abscess, is essential to prevent recurrence.