NEET MDS Synopsis
ATLS Classification
Oral and Maxillofacial SurgeryClasses of Hemorrhagic Shock (ATLS Classification)
Hemorrhagic shock is a critical condition resulting from significant blood
loss, leading to inadequate tissue perfusion and oxygenation. The Advanced
Trauma Life Support (ATLS) course classifies hemorrhagic shock into four classes
based on various physiological parameters. Understanding these classes helps
guide the management and treatment of patients experiencing hemorrhagic shock.
Class Descriptions
Class I Hemorrhagic Shock:
Blood Loss: 0-15% (up to 750 mL)
CNS Status: Slightly anxious; the patient may be
alert and oriented.
Pulse: Heart rate <100 beats/min.
Blood Pressure: Normal.
Pulse Pressure: Normal.
Respiratory Rate: 14-20 breaths/min.
Urine Output: >30 mL/hr, indicating adequate renal
perfusion.
Fluid Resuscitation: Crystalloid fluids are
typically sufficient.
Class II Hemorrhagic Shock:
Blood Loss: 15-30% (750-1500 mL)
CNS Status: Mildly anxious; the patient may show
signs of distress.
Pulse: Heart rate >100 beats/min.
Blood Pressure: Still normal, but compensatory
mechanisms are activated.
Pulse Pressure: Decreased due to increased heart
rate and peripheral vasoconstriction.
Respiratory Rate: 20-30 breaths/min.
Urine Output: 20-30 mL/hr, indicating reduced renal
perfusion.
Fluid Resuscitation: Crystalloid fluids are still
appropriate.
Class III Hemorrhagic Shock:
Blood Loss: 30-40% (1500-2000 mL)
CNS Status: Anxious or confused; the patient may
have altered mental status.
Pulse: Heart rate >120 beats/min.
Blood Pressure: Decreased; signs of hypotension may
be present.
Pulse Pressure: Decreased.
Respiratory Rate: 30-40 breaths/min.
Urine Output: 5-15 mL/hr, indicating significant
renal impairment.
Fluid Resuscitation: Crystalloid fluids plus blood
products may be necessary.
Class IV Hemorrhagic Shock:
Blood Loss: >40% (>2000 mL)
CNS Status: Confused or lethargic; the patient may
be unresponsive.
Pulse: Heart rate >140 beats/min.
Blood Pressure: Decreased; severe hypotension is
likely.
Pulse Pressure: Decreased.
Respiratory Rate: >35 breaths/min.
Urine Output: Negligible, indicating severe renal
failure.
Fluid Resuscitation: Immediate crystalloid and
blood products are critical.
Lymphopenia
General Pathology
Lymphopenia:
Causes
-As part of pancytopenia.
-Steroid administration.
Osteoradionecrosis
Oral and Maxillofacial SurgeryOsteoradionecrosis
Osteoradionecrosis (ORN) is a condition that can occur following radiation
therapy, particularly in the head and neck region, leading to the death of bone
tissue due to compromised blood supply. The management of ORN is complex and
requires a multidisciplinary approach. Below is a comprehensive overview of the
treatment strategies for osteoradionecrosis.
1. Debridement
Purpose: Surgical debridement involves the removal of
necrotic and infected tissue to promote healing and prevent the spread of
infection.
Procedure: This may include the excision of necrotic
bone and soft tissue, allowing for better access to healthy tissue.
2. Control of Infection
Antibiotic Therapy: Broad-spectrum antibiotics are
administered to control any acute infections present. However, it is
important to note that antibiotics may not penetrate necrotic bone
effectively due to poor circulation.
Monitoring: Regular assessment of infection status is
crucial to adjust antibiotic therapy as needed.
3. Hospitalization
Indication: Patients with severe ORN or those requiring
surgical intervention may need hospitalization for close monitoring and
management.
4. Supportive Treatment
Hydration: Fluid therapy is essential to maintain
hydration and support overall health.
Nutritional Support: A high-protein and vitamin-rich
diet is recommended to promote healing and recovery.
5. Pain Management
Analgesics: Both narcotic and non-narcotic analgesics
are used to manage pain effectively.
Regional Anesthesia: Techniques such as bupivacaine
(Marcaine) injections, alcohol nerve blocks, nerve avulsion, and rhizotomy
may be employed for more effective pain control.
6. Good Oral Hygiene
Oral Rinses: Regular use of oral rinses, such as 1%
sodium fluoride gel, 1% chlorhexidine gluconate, and plain water, helps
prevent radiation-induced caries and manage xerostomia and mucositis. These
rinses can enhance local immune responses and antimicrobial activity.
7. Frequent Irrigations of Wounds
Purpose: Regular irrigation of the affected areas helps
to keep the wound clean and free from debris, promoting healing.
8. Management of Exposed Dead Bone
Removal of Loose Bone: Small pieces of necrotic bone
that become loose can be removed easily to reduce the risk of infection and
promote healing.
9. Sequestration Techniques
Drilling: As recommended by Hahn and Corgill (1967),
drilling multiple holes into vital bone can encourage the sequestration of
necrotic bone, facilitating its removal.
10. Sequestrectomy
Indication: Sequestrectomy involves the surgical
removal of necrotic bone (sequestrum) and is preferably performed
intraorally to minimize complications associated with skin and vascular
damage from radiation.
11. Management of Pathological Fractures
Fracture Treatment: Although pathological fractures are
not common, they may occur from minor injuries and do not heal readily. The
best treatment involves:
Excision of necrotic ends of both bone fragments.
Replacement with a large graft.
Major soft tissue flap revascularization may be necessary to support
reconstruction.
12. Bone Resection
Indication: Bone resection is performed if there is
persistent pain, infection, or pathological fracture. It is preferably done
intraorally to avoid the risk of orocutaneous fistula in
radiation-compromised skin.
13. Hyperbaric Oxygen (HBO) Therapy
Adjunctive Treatment: HBO therapy can be a useful
adjunct in the management of ORN. While it may not be sufficient alone to
support bone graft healing, it can aid in soft tissue graft healing and
minimize compartmentalization.
Epoxy Resin Sealers Composition in Endodontics
EndodonticsEpoxy resin sealers are widely used in endodontics due to their favorable
properties, including excellent sealing ability, biocompatibility, and
resistance to washout. Understanding their composition is crucial for dental
professionals to select the appropriate materials for root canal treatments.
Here’s a detailed overview of the composition of epoxy resin sealers used in
endodontics.
Key Components of Epoxy Resin Sealers
Base Component
Polyepoxy Resins:
The primary component that provides the sealing properties. These
resins are known for their strong adhesive qualities and dimensional
stability.
Commonly used polyepoxy resins include diglycidyl ether of bisphenol
A (DGEBA).
Curing Agent
Amine-Based Curing Agents:
These agents initiate the curing process of the epoxy resin, leading
to the hardening of the material.
Examples include triethanolamine (TEA) and other amine compounds
that facilitate cross-linking of the resin.
Fillers
Inorganic Fillers:
Materials such as zirconium oxide and calcium oxide are often added
to enhance the physical properties of the sealer, including
radiopacity and strength.
Fillers can also improve the flowability of the sealer, allowing it
to fill irregularities in the canal system effectively.
Plasticizers
Additives:
Plasticizers may be included to improve the flexibility and
workability of the sealer, making it easier to manipulate during
application.
Antimicrobial Agents
Incorporated Compounds:
Some epoxy resin sealers may contain antimicrobial agents to help
reduce bacterial load within the root canal system, promoting
healing and preventing reinfection.
Examples of Epoxy Resin Sealers
AH-Plus
Composition:
Contains a polyepoxy resin base, amine curing agents, and inorganic
fillers.
Properties:
Known for its excellent sealing ability, low solubility, and good
adhesion to dentin.
AD Seal
Composition:
Similar to AH-Plus, with a focus on enhancing flowability and
reducing cytotoxicity.
Properties:
Offers good sealing properties and is used in various clinical
situations.
EndoSeal MTA
Composition:
Combines epoxy resin with bioceramic materials, providing additional
benefits such as bioactivity and improved sealing.
Properties:
Known for its favorable physicochemical properties and
biocompatibility.
Clinical Implications
Selection of Sealers: The choice of epoxy resin sealer should be
based on the specific clinical situation, considering factors such as the
complexity of the canal system, the need for antimicrobial properties, and
the desired setting time.
Application Techniques: Proper mixing and application techniques
are essential to ensure optimal performance of the sealer, including
achieving a fluid-tight seal and preventing voids.
Conclusion
Epoxy resin sealers are composed of a combination of polyepoxy resins, curing
agents, fillers, and additives that contribute to their effectiveness in
endodontic treatments. Understanding the composition and properties of these
sealers allows dental professionals to make informed decisions, ultimately
enhancing the success of root canal therapy.
Here are some notable epoxy resin sealers used in endodontics, along with their
key features:
1. AH
Plus
Description: A widely used epoxy resin-based root canal sealer.
Properties:
Excellent sealing ability.
High biocompatibility.
Good adhesion to gutta-percha and dentin.
Uses: Suitable for permanent root canal fillings.
2. Dia-ProSeal
Description: A two-component epoxy resin-based system.
Properties:
Low shrinkage and high adhesion.
Outstanding flow characteristics.
Antimicrobial activity due to the addition of calcium hydroxide.
Uses: Effective for sealing lateral canals and suitable for warm
gutta-percha techniques.
3. Vioseal
Description: An epoxy resin-based root canal sealer available in a
dual syringe format.
Properties:
Good flowability and sealing properties.
Radiopaque for easy identification on radiographs.
Uses: Used for permanent root canal fillings.
4. AH
Plus Jet
Description: A variant of AH Plus that features an auto-mixing
system.
Properties:
Consistent mixing and application.
Excellent sealing and adhesion properties.
Uses: Ideal for various endodontic applications.
5. EndoREZ
Description: A resin-based sealer that combines epoxy and
methacrylate components.
Properties:
High bond strength and low solubility.
Good flow and adaptability to canal irregularities.
Uses: Suitable for permanent root canal fillings, especially in
complex canal systems.
6. Resilon
Description: A thermoplastic synthetic polymer-based root canal
filling material that can be used with epoxy resin sealers.
Properties:
Provides a monoblock effect with the sealer.
Excellent sealing ability and biocompatibility.
Uses: Used in conjunction with epoxy resin sealers for enhanced
sealing.
Conclusion
Epoxy resin sealers are essential in endodontics for achieving effective and
durable root canal fillings. The choice of sealer may depend on the specific
clinical situation, the complexity of the canal system, and the desired
properties for optimal sealing and biocompatibility.
COMPOSITE RESINS -Pit-and-Fissure Dental Sealants
Dental Materials
Pit-and-Fissure Dental Sealants
Applications/Use
Occlusal surfaces of newly erupted posterior teeth
Labial surfaces of anterior teeth with fissures
Occlusal surfaces of teeth in older patients with reduced saliva flow (because low saliva increases the susceptibility to caries)
Types
Polymerization method
Self-curing (amine accelerated)
Light curing (light accelerated)
Filler content
Unfilled-most systems are unfilled because filler tends to interfere with wear away from self-cleaning occlusal areas(sealants are designed to wear away, except where there is no self-cleaning action a common misconception is that sealants should be wear resistant)
Components
Monomer-BIS-GMA with TEGDM diluent to facilitate flow into pits and fissures prior to cure
Initiator-benzoyl peroxide (in self-cured) and diketone (in light cured)
Accelerator-amine (In light cured)
Opaque filler-I % titanium dioxide. or other colorant to make the material detectable on tooth surfaces
Reinforcing filler-generally not added because wear resistance is not required within pits and fissures
Reaction-free radical reaction
Manipulation
Preparation
Clean pits and fissures of organic debris. Do not apply fluoride before etching because it will tend to make enamel more acid resistant. Etch occlusal surfaces, pits, and fissures for 30 seconds (gel) or 60 seconds (liquid) with 37% phosphoric acid . Wash occlusal surfaces for 20 seconds. Dry etched area for 20 seconds with clean air spray. Apply sealant and polymerize
Mixing or dispensing
Self-cured-mix equal amounts of liquids in Dappen dish for 5 seconds with brush applicator. Light cured-dispense from syringe tips
Placement
-pits, fissures, and occlusal surfaces --> Allow 60 seconds for self-cured materials to set.
Finishing
Remove unpolymerized and excess material .Examine hardness of sealant. Make occlusal adjustments where necessary in sealant; some sealant materials are self-adjusting
Properties
Physical
Wetting-low-viscosity sealants wet acid etched tooth structure the best
Mechanical
Wear resistance should not be too great because sealant should be able to wear off of self-cleaning areas of tooth
Be careful to protect sealants during polishing procedures with air abrading units to prevent sealant loss
Clinical efficacy
Effectiveness is 100% if retained in pits and fissures .Requires routine clinical evaluation for resealing of areas of sealant loss attributable to poor retention .
Sealants resist effects of topical fluorides
Drugs used in cough.
Pharmacology
PHARYNGEAL DEMULCENTS
Administered in the form of lozenges, cough drops and cough linctus.
Produce soothing action on throat directly and by increasing the flow of saliva and provide symptomatic relief from dry cough.
EXPECTORANT
Expectorants are the drugs which increase the production of bronchial secretion and reduce its viscosity to facilitate its removal by coughing.
ANTITUSSIVES
They are central cough suppressants and act centrally to raise the threshold of cough centre and inhibit the cough reflex by suppressing the coordinating cough centre in the medulla oblongata.
Codeine - it depresses cough centre but is less constipating and abuse liability is low.
Pholcodeine is similar to codeine in efficacy and is longer acting. It has no analgesic or addicting property.
Noscapine is another opium alkaloid of benzylisoquinoline group. It is used as antitussive with no analgesic and drug abuse or drug dependence property.
Dextromethorphan is a synthetic compound and its dextroisomer is used as antitussive and is as effective as codeine
Pipazethate is another synthetic compound of phenothiazine category used as antitussive with little analgesic and sedative properties.
ANTIHISTAMINICS
They do not act on cough centre but provide relief due to their sedative and anticholinergic action.
BRONCHODILATORS
Bronchodilators are helpful in individuals with cough and bronchoconstriction due to bronchial hyperreactivity. They help by improving the effectiveness of cough in clearing secretions.
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)
Erythromycin
Pharmacology
Erythromycin
used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma. It is also used to treat outbreaks of chlamydia, syphilis, and gonorrhea.
Erythromycin is produced from a strain of the actinomyces Saccaropolyspora erythraea, formerly known as Streptomyces erythraeus.