NEET MDS Synopsis
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.
Azithromycin
Pharmacology
Azithromycin
Azithromycin is the first macrolide antibiotic belonging to the azalide group. Azithromycin is derived from erythromycin by adding a nitrogen atom into the lactone ring of erythromycin A, thus making lactone ring 15-membered.
Azithromycin has similar antimicrobial spectrum as erythromycin, but is more effective against certain gram-negative bacteria, particularly Hemophilus influenzae.
azithromycin is acid-stable and can therefore be taken orally without being protected from gastric acids.
Main elimination route is through excretion in to the biliary fluid, and some can also be eliminated through urinary excretion
Modified Widman Flap
PeriodontologyModified Widman Flap Procedure
The modified Widman flap procedure is a surgical technique used in
periodontal therapy to treat periodontal pockets while preserving the
surrounding tissues and promoting healing. This lecture will discuss the
advantages and disadvantages of the modified Widman flap, its indications, and
the procedural steps involved.
Advantages of the Modified Widman Flap Procedure
Intimate Postoperative Adaptation:
The main advantage of the modified Widman flap procedure is the
ability to establish a close adaptation of healthy collagenous
connective tissues and normal epithelium to all tooth surfaces. This
promotes better healing and integration of tissues post-surgery
Feasibility for Bone Implantation:
The modified Widman flap procedure is advantageous over curettage,
particularly when the implantation of bone and other substances is
planned. This allows for better access and preparation of the surgical
site for grafting .
Conservation of Bone and Optimal Coverage:
Compared to conventional reverse bevel flap surgery, the modified
Widman flap conserves bone and provides optimal coverage of root
surfaces by soft tissues. This results in:
A more aesthetically pleasing outcome.
A favorable environment for oral hygiene.
Potentially less root sensitivity and reduced risk of root
caries.
More effective pocket closure compared to pocket elimination
procedures .
Minimized Gingival Recession:
When reattachment or minimal gingival recession is desired, the
modified Widman flap is preferred over subgingival curettage, making it
a suitable choice for treating deeper pockets (greater than 5 mm) and
other complex periodontal conditions.
Disadvantages of the Modified Widman Flap Procedure
Interproximal Architecture:
One apparent disadvantage is the potential for flat or concave
interproximal architecture immediately following the removal of the
surgical dressing, particularly in areas with interproximal bony
craters. This can affect the aesthetic outcome and may require further
management .
Indications for the Modified Widman Flap Procedure
Deep Pockets: Pockets greater than 5 mm, especially in
the anterior and buccal maxillary posterior regions.
Intrabony Pockets and Craters: Effective for treating
pockets with vertical bone loss.
Furcation Involvement: Suitable for managing
periodontal disease in multi-rooted teeth.
Bone Grafts: Facilitates the placement of bone grafts
during surgery.
Severe Root Sensitivity: Indicated when root
sensitivity is a significant concern.
Procedure Overview
Incisions and Flap Reflection:
Vertical Incisions: Made to access the periodontal
pocket.
Crevicular Incision: A horizontal incision along
the gingival margin.
Horizontal Incision: Undermines and removes the
collar of tissue around the teeth.
Conservative Debridement:
Flap is reflected just beyond the alveolar crest.
Careful removal of all plaque and calculus while preserving the root
surface.
Frequent sterile saline irrigation is used to maintain a clean
surgical field.
Preservation of Proximal Bone Surface:
The proximal bone surface is preserved and not curetted, allowing
for better healing and adaptation of the flap.
Exact flap adaptation is achieved with full coverage of the bone.
Suturing:
Suturing is aimed at achieving primary union of the proximal flap
projections, ensuring proper healing and tissue integration.
Postoperative Care
Antibiotic Ointment and Periodontal Dressing:
Traditionally, antibiotic ointment was applied over sutures, and a
periodontal dressing was placed. However, these practices are often omitted
today.
Current Recommendations: Patients are advised not to
disturb the surgical area and to use a chlorhexidine mouth rinse every 12
hours for effective plaque control and to promote healing.
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Neutrophil Disorders Associated with Periodontal Diseases
Neutrophils play a crucial role in the immune response, particularly in
combating infections, including those associated with periodontal diseases.
Various neutrophil disorders can significantly impact periodontal health,
leading to increased susceptibility to periodontal diseases. This lecture will
explore the relationship between neutrophil disorders and specific periodontal
diseases.
Neutrophil Disorders
Diabetes Mellitus
Description: A metabolic disorder characterized by
high blood sugar levels due to insulin resistance or deficiency.
Impact on Neutrophils: Diabetes can impair
neutrophil function, including chemotaxis, phagocytosis, and the
oxidative burst, leading to an increased risk of periodontal infections.
Papillon-Lefevre Syndrome
Description: A rare genetic disorder characterized
by palmoplantar keratoderma and severe periodontitis.
Impact on Neutrophils: Patients exhibit neutrophil
dysfunction, leading to early onset and rapid progression of periodontal
disease.
Down’s Syndrome
Description: A genetic disorder caused by the
presence of an extra chromosome 21, leading to various developmental and
health issues.
Impact on Neutrophils: Individuals with Down’s
syndrome often have impaired neutrophil function, which contributes to
an increased prevalence of periodontal disease.
Chediak-Higashi Syndrome
Description: A rare genetic disorder characterized
by immunodeficiency, partial oculocutaneous albinism, and neurological
problems.
Impact on Neutrophils: This syndrome results in
defective neutrophil chemotaxis and phagocytosis, leading to increased
susceptibility to infections, including periodontal diseases.
Drug-Induced Agranulocytosis
Description: A condition characterized by a
dangerously low level of neutrophils due to certain medications.
Impact on Neutrophils: The reduction in neutrophil
count compromises the immune response, increasing the risk of
periodontal infections.
Cyclic Neutropenia
Description: A rare genetic disorder characterized
by recurrent episodes of neutropenia (low neutrophil count) occurring
every 21 days.
Impact on Neutrophils: During neutropenic episodes,
patients are at a heightened risk for infections, including periodontal
disease.
Regulation of Blood Pressure by Hormones
Physiology
Regulation of Blood Pressure by Hormones
The Kidney
One of the functions of the kidney is to monitor blood pressure and take corrective action if it should drop. The kidney does this by secreting the proteolytic enzyme renin.
Renin acts on angiotensinogen, a plasma peptide, splitting off a fragment containing 10 amino acids called angiotensin I.
angiotensin I is cleaved by a peptidase secreted by blood vessels called angiotensin converting enzyme (ACE) — producing angiotensin II, which contains 8 amino acids.
angiotensin II
constricts the walls of arterioles closing down capillary beds;
stimulates the proximal tubules in the kidney to reabsorb sodium ions;
stimulates the adrenal cortex to release aldosterone. Aldosterone causes the kidneys to reclaim still more sodium and thus water.
increases the strength of the heartbeat;
stimulates the pituitary to release the antidiuretic hormone (ADH, also known as arginine vasopressin).
All of these actions, which are mediated by its binding to G-protein-coupled receptors on the target cells, lead to an increase in blood pressure.
Intraligamentary Injection
Oral and Maxillofacial SurgeryIntraligamentary Injection and Supraperiosteal Technique
Intraligamentary Injection
The intraligamentary injection technique is a simple and effective
method for achieving localized anesthesia in dental procedures. It
requires only a small volume of anesthetic solution and produces rapid
onset of anesthesia.
Technique:
Needle Placement:
The needle is inserted into the gingival sulcus, typically on
the mesial surface of the tooth.
The needle is then advanced along the root surface until
resistance is encountered, indicating that the needle is positioned
within the periodontal ligament.
Anesthetic Delivery:
Approximately 0.2 ml of anesthetic solution is deposited into
the periodontal ligament space.
For multirooted teeth, injections should be made both mesially
and distally to ensure adequate anesthesia of all roots.
Considerations:
Significant pressure is required to express the anesthetic solution
into the periodontal ligament, which can be a factor to consider during
administration.
This technique is particularly useful for localized procedures where
rapid anesthesia is desired.
Supraperiosteal Technique (Local Infiltration)
The supraperiosteal injection technique is commonly used for
achieving anesthesia in the maxillary arch, particularly for
single-rooted teeth.
Technique:
Anesthetic Injection:
For the first primary molar, the bone overlying the tooth is
thin, allowing for effective anesthesia by injecting the anesthetic
solution opposite the apices of the roots.
Challenges with Multirooted Teeth:
The thick zygomatic process can complicate the anesthetic
delivery for the buccal roots of the second primary molar and first
permanent molars.
Due to the increased thickness of bone in this area, the
supraperiosteal injection at the apices of the roots of the second
primary molar may be less effective.
Supplemental Injection:
To enhance anesthesia, a supplemental injection should be
administered superior to the maxillary tuberosity area to block the
posterior superior alveolar nerve.
This additional injection compensates for the bone thickness and
the presence of the posterior middle superior alveolar nerve plexus,
which can affect the efficacy of the initial injection.
Drugs Used in Diabetes -Glitazones
Pharmacology
Glitazones (thiazolidinediones)
Thiazolidinediones, also known as the "-glitazones"
pioglitazone
rosiglitazone
Mechanism
bind to nuclear receptors involved in transcription of genes mediating insulin sensitivity
peroxisome proliferator-activating receptors (PPARs)
↑ insulin sensitivity in peripheral tissue
↓ gluconeogenesis
↑ insulin receptor numbers
↓ triglycerides
Clinical use
type II DM
as monotherapy or in combination with other agents
contraindicated in CHF
associated with increased risk of MI (in particular rosiglitazone)
Mucormycosis
General Pathology
FUNGAL INFECTION
Mucormycosis (Zygomycosis; Phycomycosis)
Infection with tissue invasion by broad, nonseptate, irregularly shaped hyphae of diverse fungal species, including Rhizopus, Rhizomucor, Absidia, and Basidiobolus.
Infection is most common in immunosuppressed persons, in patients with poorly controlled diabetes, and in patients receiving the iron-chelating drug desferrioxamine.
Symptoms and Signs
Rhinocerebral mucormycosis is the most common form, but primary cutaneous, pulmonary, or GI lesions sometimes develop, and hematogenous dissemination to other sites can occur. Rhinocerebral infections are usually fulminant and frequently fatal. Necrotic lesions usually appear on the nasal mucosa or sometimes the palate.
Impression Materials -Classification
Dental Materials
Classification
Rigid impression materials
(1) Plaster
(2) Compound
(3) Zinc oxide-eugenol
Flexible hydrocolloid impression materials
(I) Agar-agar (reversible hydrocolloid)
(2) Alginate (irreversible hydrocolloid)
Flexible, elastomeric, or rubber impression materials
(1) Polysulfide rubber (mercaptan rubber)
(2) Silicone rubber (condensation silicone)
(3) Polyether rubber
(4) Polyvinyl siloxane (addition silicone)