NEET MDS Synopsis
Local anesthetic selection
Pharmacology
Local anesthetic selection
Local anesthetics are typically divided into 3 main categories:
short, intermediate and long acting local anesthetics.
Based on duration of the procedure and the duration of the individual agents
Infiltration
Nerve block
Pulpal
Soft tissue
Pulpal
Soft tissue
Short
30 min
2-3 hrs
45 min
2-3 hrs
Intermediate
60 min
2-3 hrs
75-90 min
3-4 hrs
Long
40 min
5-6 hrs
3-4 hrs
6-8 hrs
Short acting agents
1. Mepivacaine 3 %
2. Lidocaine 2%
Intermediate acting agents
1. Lidocaine 2% 1:100000 epi
2. Lidocaine 2% 1:50000 epi
3. Mepivacaine 2% 1:20000 neocobefrin
4. Prilocaine 4%
5. Articaine 4% 1:100000 epi
Long acting agents
1. Bupivacaine 0.5% 1:200000 epi
Immunohistochemistry
General Pathology
Immunohistochemistry
This is a method is used to detect a specific antigen in the tissue in order to identify the type of disease.
The Nasopharynx
AnatomyThe Nasopharynx
The nasal part of the pharynx has a respiratory function.
It lies superior to the soft palate and is a posterior extension of the nasal cavity.
The nose opens into the nasopharynx via to large posterior apertures called choanae.
The roof and posterior wall of the nasopharynx form a continuous surface that lies inferior to the body of the sphenoid bone and the basilar part of the occipital bone.
In the mucous membrane of the roof of the posterior wall of the nasopharynx is a collection of lymphoid tissue, known as the pharyngeal tonsil (commonly known as the adenoids).
The pharyngeal orifice of the auditory tube is on the lateral wall of the nasopharynx, 1 to 1.5 cm posterior to the inferior concha, and level with the superior border of the palate.
The orifice is directed inferiorly and has a hood-like tubal elevation over it called the torus of the auditory tube or the torus tubarius (L. torus, swelling).
Extending inferiorly from the torus is a vertical fold of mucous membrane, known as the salpingopharyngeal fold.
The collection of lymphoid tissue in the submucosa of the pharynx, posterior to the orifice of the auditory tube, is known as the tubal tonsil.
Posterior to the torus and the salpingopharyngeal fold, there is a slit-like lateral projection of the pharynx called the pharyngeal recess.
It extends laterally and posteriorly.
Comparison of Fatty acid synthesis and b-oxidation pathways
Biochemistry
b Oxidation Pathway
Fatty Acid Synthesis
pathway location
mitochondrial matrix
cytosol
acyl carriers (thiols)
Coenzyme-A
phosphopantetheine (ACP) & cysteine
electron acceptors/donor
FAD & NAD+
NADPH
hydroxyl intermediate
L
D
2-C product/donor
acetyl-CoA
malonyl-CoA (& acetyl-CoA)
Champy Technique of Fracture Stabilization
Oral and Maxillofacial SurgeryChampy Technique of Fracture Stabilization
The Champy technique, developed by Champy et al. in the mid-1970s, is a
method of fracture stabilization that utilizes non-compression monocortical
miniplates applied as tension bands. This technique is particularly relevant in
the context of mandibular fractures and is based on biomechanical principles
that optimize the stability and healing of the bone.
Key Principles of the Champy Technique
Biomechanical Considerations:
Tensile and Compressive Stresses: Biomechanical
studies have shown that tensile stresses occur in the upper border of
the mandible, while compressive stresses are found in the lower border.
This understanding is crucial for the placement of plates.
Bending and Torsional Forces: The forces acting on
the mandible primarily produce bending movements. In the symphysis and
parasymphysis regions, torsional forces are more significant than
bending moments.
Ideal Osteosynthesis Line:
Champy et al. established the "ideal osteosynthesis line" at the
base of the alveolar process. This line is critical for the effective
placement of plates to ensure stability during the healing process.
Plate Placement:
Anterior Region: In the area between the mental
foramina, a subapical plate is placed, and an additional plate is
positioned near the lower border of the mandible to counteract
torsional forces.
Posterior Region: Behind the mental foramen,
the plate is applied just below the dental roots and above the
inferior alveolar nerve.
Angle of Mandible: The plate is placed on the
broad surface of the external oblique ridge.
Tension Band Principle:
The use of miniplates as tension bands allows for the distribution
of forces across the fracture site, enhancing stability and promoting
healing.
Treatment Steps
Reduction:
The first step in fracture treatment is the accurate reduction of
the fracture fragments to restore normal anatomy.
Stabilization:
Following reduction, stabilization is achieved using the Champy
technique, which involves the application of miniplates in accordance
with the biomechanical principles outlined above.
Maxillomandibular Fixation (MMF):
MMF is often used as a standard method for both reduction and
stabilization, particularly in cases where additional support is needed.
External Fixation:
In cases of atrophic edentulous mandibular fractures, extensive soft
tissue injuries, severe communication, or infected fractures, external
fixation may be considered.
Classification of Internal Fixation Techniques
Absolute Stability:
Rigid internal fixation methods, such as compression plates, lag
screws, and the tension band principle, fall under this category. These
techniques provide strong stabilization but may compromise blood supply
to the bone.
Relative Stability:
Techniques such as bridging, biologic (flexible) fixation, and the
Champy technique are classified as relative stability methods. These
techniques allow for some movement at the fracture site, which can
promote healing by maintaining blood supply to the cortical bone.
Biologic Fixation
New Paradigm:
Biologic fixation represents a shift in fracture treatment
philosophy, emphasizing that absolute stability is not always
beneficial. Allowing for some movement at the fracture site can enhance
blood supply and promote healing.
Improved Blood Supply:
Not pressing the plate against the bone helps maintain blood supply
to the cortical bone and prevents the formation of early temporary
porosity, which can be detrimental to healing.
CASTING
Dental Materials
CASTING: casting is the process by which the wax pattern of a restoration is converted to a replicate in a dental alloy. The casting process is used to make dental restorations such as inlays, onlays, crowns, bridges and removable partial dentures.
Objectives of casting
1) To heat the alloy as quickly as possible to a completely molten condition.
2) To prevent oxidation by heating the metal with awell adjusted torch .
3) To produce a casting with sharp details by having adequate pressure to the well melted metal to force into the mold.
STEPS IN MAKING A CAST RESTORATION
1. TOOTH PREPARATION
2. IMPRESSION
3. DIE PREPARATION
4. WAX PATTERN FABRICATION
5. SPRUING
TetricEvoFlow
PedodonticsTetricEvoFlow
TetricEvoFlow is an advanced nano-optimized flowable composite developed by
Ivoclar Vivadent, designed to enhance dental restorations with its superior
properties. As the successor to Tetric Flow, it offers several key benefits:
Optimum Surface Affinity: TetricEvoFlow exhibits
excellent adhesion to tooth structures, ensuring a reliable bond and
minimizing the risk of microleakage.
Penetration into Difficult Areas: Its flowable nature
allows it to reach and fill even the most challenging areas, making it ideal
for intricate restorations.
Versatile Use: This composite can serve as an initial
layer beneath medium-viscosity composites, such as TetricEvoCeram, providing
a strong foundation for layered restorations.
Stability for Class V Restorations: TetricEvoFlow
maintains its stability when required, making it particularly suitable for
Class V restorations, where durability and aesthetics are crucial.
Extended Applications: In addition to its use in
restorations, TetricEvoFlow is effective for extended fissure sealing and
can be utilized in adhesive cementation techniques.
Drugs Used in Diabetes -Megltinides
Pharmacology
Megltinides
nateglinide
repaglinide
Mechanism
binds to K+ channels on β-cells → postprandial insulin release
Clinical use
type 2 diabetes mellitus
may be used as monotherapy, or in combination with metformin