NEET MDS Synopsis
Eicosanoid compounds
Pharmacology
Eicosanoid compounds
Prostaglandines, Leukotriens and Thromboxanes.
They are produced in minute amounts by all cells except RBCs and they act locally at the same site of synthesis.
These agents have many physiological processes as mediators and modulators of inflammatory reactions.
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.
MAXILLARY FIRST BICUSPID
Dental Anatomy
MAXILLARY FIRST BICUSPID (PREMOLARS)
It is considered to be the typical bicuspid. (The word "bicuspid" means "having two cusps.")
Facial: The buccal surface is quite rounded and this tooth resembles the maxillary canine. The buccal cusp is long; from that cusp tip, the prominent buccal ridge descends to the cervical line of the tooth.
Lingual: The lingual cusp is smaller and the tip of that cusp is shifted toward the mesial. The lingual surface is rounded in all aspects.
Proximal: The mesial aspect of this tooth has a distinctive concavity in the cervical third that extends onto the root. It is called variously the mesial developmental depression, mesial concavity, or the 'canine fossa'--a misleading description since it is on the premolar. The distal aspect of the maxillary first permanent molar also has a developmental depression. The mesial marginal developmental groove is a distinctive feature of this tooth.
Occlusal: There are two well-defined cusps buccal and lingual. The larger cusp is the buccal; its cusp tip is located midway mesiodistally. The lingual cusp tip is shifted mesially. The occlusal outline presents a hexagonal appearance. On the mesial marginal ridge is a distinctive feature, the mesial marginal developmental groove.
Contact Points;The distal contact area is located more buccal than is the mesial contact area.
Root Surface:-The root is quite flat on the mesial and distal surfaces. In about 50 percent of maxillary first bicuspids, the root is divided in the apical third, and when it so divided, the tips of the facial and lingual roots are slender and finely tapered.
Fillers in Composite Resin
Conservative DentistryFillers in composite resin are inorganic particles that enhance the mechanical
and optical properties of the material. They come in various sizes, shapes, and
compositions. The choice of filler influences the resin's strength, wear
resistance, and polishability.
Types of fillers:
- Silica: Common in microfilled and hybrid composites,
providing good aesthetics and polishability.
- Glass particles: Used in macrofill and microfill composites
for high strength and durability.
- Ceramic particles: Provide excellent biocompatibility and
wear resistance.
- Zirconia/silica: Combined to improve the strength and
translucency of the composite.
- Nanoparticles: Enhance the resin's physical properties,
including strength and wear resistance, while also offering improved aesthetics.
Filler size:
- Macrofillers: 10-50 μm, suitable for class I and II
restorations where high strength is not essential but a good seal is required.
- Microfillers: 0.01-10 μm, used for fine detailing and
aesthetic restorations due to their ability to blend with the tooth structure.
- Hybrid fillers: Combine macro and microfillers for
restorations requiring both strength and aesthetics.
Filler loading: The amount of filler in the resin affects the
material's physical properties:
- High filler loading: Increases strength, wear resistance, and
decreases shrinkage but can compromise the resin's ability to adapt to the tooth
structure.
- Low filler loading: Provides better flow and marginal
adaptation but may result in lower strength and durability.
Filler-resin interaction:
- Chemical bonding: Improves the adhesion between the filler
and the resin matrix.
- Mechanical interlocking: Larger filler particles create a
stronger mechanical bond within the resin.
- Polymerization shrinkage: The filler can reduce shrinkage
stress, which is crucial for minimizing marginal gaps and microleakage.
Selection criteria:
- Clinical requirements: The filler should meet the specific needs of the
restoration, such as strength, wear resistance, and aesthetics.
- Tooth location: Anterior teeth may require more translucent fillers for better
aesthetics, while posterior teeth need stronger, more opaque materials.
- Patient's preferences: Some patients may prefer more natural-looking
restorations.
- Clinician's skill: Different fillers may require varying application
techniques and curing times.
Umbilical cord prolapse
Obstetrics and Gynaecology
Umbilical cord prolapse
acute, life-threatening emergency for the fetus, in which a part of the umbilical cord lies between the antecedent part of the fetus (mostly head) and the pelvic wall, causing rupture of membranes
Epidemiology: rare (0.5% births)
Etiology: often seen in presentation anomalies (e.g., breech presentation, transverse fetal position), multiple pregnancy, long umbilical cord, or abnormal fetal movement (polyhydramnios, premature birth)
Clinical features: -
- an abrupt change from a previously normal CTG to one with fetal bradycardia or recurrent,
- severe decelerations,
- occuring after the rupture of membranes
Diagnostics: vaginal palpation → thick, pulsating cord is palpable
Treatment: Trendelenburg position; fetus is pushed back into the uterus; immediate tocolysis using β2-mimetics (e.g., fenoterol) → emergency cesarean section
Multiple myeloma
General Pathology
Multiple myeloma.
Blood picture:
- Marked rouleaux formation.
- Normpcytic normochromic anaemia.
- There may be leucopenia or leucoery!hrohlastic reaction.
- Atypical plasma cells may be seen in some patients
- Raised ESR
- Monoclonal hypergammaglobulinaemia
- If light chains are produced in excess, they are excreted in urine as bence jones protein
Bone marrow
- Hyper cellular
- Plasma cells from at least 15 – 30% atypical forms and myeloma cells are seen.
The Bicarbonate Buffer System
Biochemistry
The Bicarbonate Buffer System
This is the main extracellular buffer system which (also) provides a means for the necessary removal of the CO2 produced by tissue metabolism. The bicarbonate buffer system is the main buffer in blood plasma and consists of carbonic acid as proton donor and bicarbonate as proton acceptor :
H2CO3 = H+ + HCO3–
If there is a change in the ratio in favour of H2CO3, acidosis results.
This change can result from a decrease in [HCO3 − ] or from an increase in [H2CO3 ]
Most common forms of acidosis are metabolic or respiratory
Metabolic acidosis is caused by a decrease in [HCO3 − ] and occurs, for example, in uncontrolled diabetes with ketosis or as a result of starvation.
Respiratory acidosis is brought about when there is an obstruction to respiration (emphysema, asthma or pneumonia) or depression of respiration (toxic doses of morphine or other respiratory depressants)
Alkalosis results when [HCO3 − ] becomes favoured in the bicarbonate/carbonic acid ratio
Metabolic alkalosis occurs when the HCO3 − fraction increases with little or no concomitant change in H2CO3
Severe vomiting (loss of H+ as HCl) or ingestion of excessive amounts of sodium bicarbonate (bicarbonate of soda) can produce this condition
Respiratory alkalosis is induced by hyperventilation because an excessive removal of CO2 from the blood results in a decrease in [H2CO3 ]
Alkalosis can produce convulsive seizures in children and tetany, hysteria, prolonged hot baths or lack of O2 as high altitudes.
The pH of blood is maintained at 7.4 when the buffer ratio [HCO3 − ] / [ H2CO3] becomes 20
Supplemental fluoride recommendations
PedodonticsInfants (0 - 6 months): No fluoride supplementation is recommended regardless of water fluoridation levels.
Toddlers (0.5 - 3 years): Supplementation is recommended only if the water fluoridation level is less than 0.3 ppm.
Preschoolers (3 - 6 years): Dosages vary based on water fluoridation levels, with higher dosages for lower fluoride levels.
Children over 6 years: Higher dosages are recommended for lower fluoride levels, but no supplementation is needed if the water fluoridation level exceeds 0.6 ppm.