NEET MDS Synopsis
Composition of Stainless Steel Crowns
PedodonticsComposition of Stainless Steel Crowns
Stainless steel crowns (SSCs) are primarily made from a specific type of
stainless steel alloy, which provides the necessary strength, durability, and
resistance to corrosion. Here’s a breakdown of the composition of the commonly
used stainless steel crowns:
1. Stainless Steel (18-8) Austenitic Alloy:
Common Brands: Rocky Mountain, Unitek
Composition:
Iron: 67%
Chromium: 17%
Nickel: 12%
Carbon: 0.08 - 0.15%
This composition provides the crowns with excellent mechanical properties and
resistance to corrosion, making them suitable for use in pediatric dentistry.
2. Nickel-Based Crowns:
Examples: Inconel 600, 3M crowns
Composition:
Iron: 10%
Chromium: 16%
Nickel: 72%
Others: 2%
Nickel-based crowns are also used in some cases, offering different
properties and benefits, particularly in terms of strength and biocompatibility.
The Skeleton of the Nose
AnatomyThe Skeleton of the Nose
The immovable bridge of the nose, the superior bony part of the nose, consists of the nasal bones, the frontal processes of the maxillae, and the nasal part of the frontal bones.
The movable cartilaginous part consists of five main cartilages and a few smaller ones.
The U-shaped alar nasal cartilages are free and movable.
They dilate and constrict the external nares when the muscles acting on the external nose contract.
The Nasal Cavities
The nasal cavities are entered through the anterior nares or nostrils.
They open into the nasopharynx through the choanae.
The Roof and Floor of the Nasal Cavity
The roof is curved and narrow, except at the posterior end.
The floor is wider than the roof.
It is formed from the palatine process of the maxilla and the horizontal plate of the palatine bone.
The Walls of the Nasal Cavity
The medial wall is formed by the nasal septum; it is usually smooth.
The lateral wall is uneven owing to the three longitudinal, scroll-shaped elevations, called the conchae (L. shells) or turbinates (L. shaped like a top).
These elevations are called the superior, middle and inferior conchae according to their position.
The superior and middle conchae are parts of the ethmoid bone, whereas the inferior conchae are separate bones.
The inferior and middle conchae project medially and inferiorly, producing air passageways called the inferior and middle meatus (L. passage). Note: the plural of "meatus" is the same as the singular.
The short superior conchae conceal the superior meatus.
The space posterosuperior to the superior concha is called the sphenoethmoidal recess.
INTRAARCH AND INTERARCH RELATIONSHIPS
Dental Anatomy
lntraarch relationship refers to the alignment of the teeth within an arch
1. In an ideal alignment teeth should contact at their proximal crests of curvature. A continuous arch form is observed in occlusal view
Curves of the occlusal plane (a line connecting the cusp tips of the canines, premolars, and molars) are observed from the proximal view
Curve of Spee: anterior to posterior curve; for mandibular teeth the curve is concave and for maxillary teeth it is convex
Curve of Wilson- medial to lateral curve for mandibular teeth the curve is also convex and for the maxillary it is convex
2. Contact does not always exist Some permanent dentitions have normal spacing
Primary dentitions often have developmental spacing in the anterior area: some primary den titions have a pattern of spacing called primate spaces between the primary maxillary lateral incisors and canine and between the mandibular canine and first mo1ar
Disturbances to the intraarch alignment are described as
a. Qpen contact where interproximal space exist because of missing teeth oral habits, dental disease, or overdeveloped frena
b. where contact or position is at an unexpected area because of developmental disturbances, crowding, dental caries or periodontal ligament for their misplaced position: facial, lingual. mesial, supra(supraerupted) infra (infraerupted) and torso (rotated) version
Pleural effusion
General Pathology
Pleural effusion is a medical condition where fluid accumulates in the pleural cavity which surrounds the lungs, making it hard to breathe.
Four main types of fluids can accumulate in the pleural space:
Serous fluid (hydrothorax)
Blood (hemothorax)
Lipid (chylothorax)
Pus (pyothorax or empyema)
Causes:
Pleural effusion can result from reasons such as:
Cancer, including lung cancer or breast cancer
Infection such as pneumonia or tuberculosis
Autoimmune disease such as lupus erythematosus
Heart failure
Bleeding, often due to chest trauma (hemothorax)
Low oncotic pressure of the blood plasma
lymphatic obstruction
Accidental infusion of fluids
Congestive heart failure, bacterial pneumonia and lung cancer constitute the vast majority of causes in the developed countries, although tuberculosis is a common cause in the developing world.
Diagnosis:
Gram stain and culture - identifies bacterial infections
Cell count and differential - differentiates exudative from transudative effusions
Cytology - identifies cancer cells, may also identify some infective organisms
Chemical composition including protein, lactate dehydrogenase, amylase, pH and glucose - differentiates exudative from transudative effusions
Other tests as suggested by the clinical situation - lipids, fungal culture, viral culture, specific immunoglobulins
Carisolv
Conservative DentistryCarisolvCarisolv is a dental caries removal system that offers a unique approach to
the treatment of carious dentin. It differs from traditional methods, such as
Caridex, by utilizing amino acids and a lower concentration of sodium
hypochlorite. Below is an overview of its components, mechanism of action,
application process, and advantages.
1. Components of Carisolv
A. Red Gel (Solution A)
Composition:
Amino Acids: Contains 0.1 M of three amino acids:
I-Glutamic Acid
I-Leucine
I-Lysine
Sodium Hydroxide (NaOH): Used to adjust pH.
Sodium Hypochlorite (NaOCl): Present at a lower
concentration compared to Caridex.
Erythrosine: A dye that provides color to the gel,
aiding in visualization during application.
Purified Water: Used as a solvent.
B. Clear Liquid (Solution B)
Composition:
Sodium Hypochlorite (NaOCl): Contains 0.5% NaOCl
w/v, which contributes to the antimicrobial properties of the solution.
C. Storage and Preparation
Temperature: The two separate gels are stored at 48°C
before use and are allowed to return to room temperature prior to
application.
2. Mechanism of Action
Softening Carious Dentin: Carisolv is designed to
soften carious dentin by chemically disrupting denatured collagen within the
affected tissue.
Collagen Disruption: The amino acids in the formulation
play a crucial role in breaking down the collagen matrix, making it easier
to remove the softened carious dentin.
Scraping Away: After the dentin is softened, it is
removed using specially designed hand instruments, allowing for precise and
effective caries removal.
3. pH and Application Time
Resultant pH: The pH of Carisolv is approximately 11,
which is alkaline and conducive to the softening process.
Application Time: The recommended application time for
Carisolv is between 30 to 60 seconds, allowing for quick
treatment of carious lesions.
4. Advantages
Minimally Invasive: Carisolv offers a minimally
invasive approach to caries removal, preserving healthy tooth structure
while effectively treating carious dentin.
Reduced Need for Rotary Instruments: The chemical
action of Carisolv reduces the reliance on traditional rotary instruments,
which can be beneficial for patients with anxiety or those requiring a
gentler approach.
Visualization: The presence of erythrosine allows for
better visualization of the treated area, helping clinicians ensure complete
removal of carious tissue.
ZINC
Biochemistry
ZINC
The enzyme RNA polymerase, which is required for transcription, contains zinc and it is essential for protein bio synthesis.
Deficiency in Zinc leads to poor wound healing, lesions of skin impaired spermatogenesis, hyperkeratosis, dermatitis and alopecia
Nutrition and tooth development
Dental Anatomy
Nutrition and tooth development
As in other aspects of human growth and development, nutrition has an effect on the developing tooth. Essential nutrients for a healthy tooth include calcium, phosphorus, fluoride, and vitamins A, C, and D. Calcium and phosphorus are needed to properly form the hydroxyapatite crystals, and their levels in the blood are maintained by Vitamin D. Vitamin A is necessary for the formation of keratin, as Vitamin C is for collagen. Fluoride is incorporated into the hydroxyapatite crystal of a developing tooth and makes it more resistant to demineralization and subsequent decay.
Deficiencies of these nutrients can have a wide range of effects on tooth development. In situations where calcium, phosphorus, and vitamin D are deficient, the hard structures of a tooth may be less mineralized. A lack of vitamin A can cause a reduction in the amount of enamel formation. Fluoride deficency causes increased demineralization when the tooth is exposed to an acidic environment, and also delays remineralization. Furthermore, an excess of fluoride while a tooth is in development can lead to a condition known as fluorosis.
Pentose Phosphate Pathway (Hexose Monophosphate Shunt)
Biochemistry
Pentose Phosphate Pathway (Hexose Monophosphate Shunt)
The pentose phosphate pathway is primarily an anabolic pathway that utilizes the 6 carbons of glucose to generate 5 carbon sugars and reducing equivalents. However, this pathway does oxidize glucose and under certain conditions can completely oxidize glucose to CO2 and water. The primary functions of this pathway are:
To generate reducing equivalents, in the form of NADPH, for reductive biosynthesis reactions within cells.
To provide the cell with ribose-5-phosphate (R5P) for the synthesis of the nucleotides and nucleic acids.
Although not a significant function of the PPP, it can operate to metabolize dietary pentose sugars derived from the digestion of nucleic acids as well as to rearrange the carbon skeletons of dietary carbohydrates into glycolytic/gluconeogenic intermediates
Enzymes that function primarily in the reductive direction utilize the NADP+/NADPH cofactor pair as co-factors as opposed to oxidative enzymes that utilize the NAD+/NADH cofactor pair. The reactions of fatty acid biosynthesis and steroid biosynthesis utilize large amounts of NADPH. As a consequence, cells of the liver, adipose tissue, adrenal cortex, testis and lactating mammary gland have high levels of the PPP enzymes. In fact 30% of the oxidation of glucose in the liver occurs via the PPP. Additionally, erythrocytes utilize the reactions of the PPP to generate large amounts of NADPH used in the reduction of glutathione. The conversion of ribonucleotides to deoxyribonucleotides (through the action of ribonucleotide reductase) requires NADPH as the electron source, therefore, any rapidly proliferating cell needs large quantities of NADPH.
Regulation: Glucose-6-phosphate Dehydrogenase is the committed step of the Pentose Phosphate Pathway. This enzyme is regulated by availability of the substrate NADP+. As NADPH is utilized in reductive synthetic pathways, the increasing concentration of NADP+ stimulates the Pentose Phosphate Pathway, to replenish NADPH