NEET MDS Synopsis
LOCATION OF THE TEETH
Dental Anatomy
LOCATION OF THE TEETH
Normally, a human receives two sets of teeth during a lifetime.
The first (deciduous or primary) set consists of 20 teeth ("baby" teeth).
The second (permanent) set usually consists of 32 teeth. In each quadrant, there are eight permanent teeth: two incisors, one cuspid, two bicuspids, and three molars
The tooth positioned immediately to the side of the midline is the central incisor, so called because it occupies a central location in the arch.
To the side of the central incisor is the lateral incisor. Next is the cuspid, then the two bicuspids (the first bicuspid, followed by the second bicuspid). The last teeth are three molars. After the second bicuspid comes the first molar, followed by the second molar, followed by the third molar or more commonly called the "wisdom tooth."
Another method of describing the location of teeth is to refer to them as anterior or posterior teeth .
Anterior teeth are those located in the front of the mouth, the incisors, and the cuspids. Normally, these are the teeth that are visible when a person smiles.
The posterior teeth are those located in the back of the mouth-the bicuspids and molars.
Dental Terminology
Dental Anatomy
Dental Terminology.
Cusp: a point or peak on the occlusal surface of molar and premolar teeth and on the incisal edges of canines.
Contact: a point or area where one tooth is in contact (touching) another tooth
Cingulum: a bulge or elevation on the lingual surface of incisors or canines. It makes up the bulk of the cervical third of the lingual surface. Its convexity mesiodistally resembles a girdle encircling the lingual surface at the cervical.
Fissure: A linear fault that sometimes occurs in a developmental groove by incomplete or imperfect joining of the lobes. A pit is usually found at the end of a developmental groove or a place where two fissures intersect.
Lobe: one of the primary centers of formation in the development of the crown of the tooth.
Mamelon: A lobe seen on anterior teeth; any one of three rounded protuberances seen on the unworn surfaces of freshly erupted anterior teeth.
Ridge: Any linear elevation on the surface of a tooth. It is named according to its location or form. Examples are buccal ridges, incisal ridges, marginal ridges, and so on.
Marginal ridges are those rounded borders of enamel which form the margins of the surfaces of premolars and molars, mesially and distally, and the mesial and distal margins of the incisors and canines lingually.
Triangular ridges are those ridges which descend from the tips of the cusps of molars and premolars toward the central part of the occlusal surface. Transverse ridges are created when a buccal and lingual triangular ridge join.
Oblique ridges are seen on maxillary molars and are a companion to the distal oblique groove.
Cervical ridges are the height of contour at the gingival, on certain deciduous and permanent teeth.
Fossa: An irregular, rounded depression or concavity found on the surface of a tooth. A lingual fossa is found on the lingual surface of incisors. A central fossa is found on the occlusal surface of a molar. They are formed by the converging of ridges terminating at a central point in the bottom of a depression where there is a junction of grooves
Pit: A small pinpoint depression located at the junction of developmental grooves or at the terminals of these groops. A central pit is found in the central fossa on the occlusal surfaces of molars where developmental grooves join. A pit is often the site of the onset of Dental caries
Developmental groove: A sharply defined, narrow and linear depression formed during tooth development and usually separating lobes or major portions of a tooth.
A supplemental groove is also a shallow linear depression but it is usually less distinct and is more variable than a developmental groove and does not mark the junction of primary parts of a tooth.
Buccal and lingual grooves are developmental grooves found on the buccal and lingual surfaces of posterior teeth.
Tubercle: A small elevation produced by an extra formation of enamel. These occur on the marginal ridges of posterior teeth or on the cingulum of anterior teeth. These are deviations from the typical form.
Interproximal space: The triangular space between the adjacent teeth cervical to the contact point. The base of the triangle is the alveolar bone; the sides are the proximal surfaces of the adjacent teeth.
Sulcus:-An elongated valley or depression in the surface of a tooth formed by the inclines of adjacent cusp or ridges.
Embrasures: When two teeth in the same arch are in contact, their curvatures adjacent to the contact areas form spillway spaces called embrasures. There are three embrasures:
(1) Facial (buccal or labial)
(2) Occlusal or incisal
(3) Lingual
(NOTE: there are three embrasures; the fourth potential space is the interproximal space ).
Biochemical examination
General Pathology
Biochemical examination
This is a method by which the metabolic disturbances of disease are investigated by assay of various normal and abnormal compounds in the blood, urine, etc.
Effects and Toxic Actions on Organ Systems
Pharmacology
Effects and Toxic Actions on Organ Systems
1. Local anesthetics (dose dependent) interfere with transmission in any excitable tissue (e.g. CNS and CVS).
2. CNS effects
a. Central neurons very sensitive.
b. Excitatory-dizziness, visual and auditory disturbances, apprehension, disorientation and muscle twitching more common with ester type agents.
c. Depression manifested as slurred speech, drowsiness and unconsciousness more common with amide type agents (e.g. lidocaine).
d. Higher concentrations of local anesthetic may eventually produce tonic-clonic[grand mal] convulsions.
e. Very large doses may produce respiratory depression which can be fatal. Artificial respiration may be life-saving.
3.CVS effects
a. Local anesthetics have direct action on the myocardium and peripheral vasculature by closing the sodium channel, thereby limiting the inward flux of sodium ions.
b. Myocardium usually depressed both in rate and force of contraction. Depression of ectopic pacemakers useful in treating cardiac arrhythmias.
c. Concentrations employed clinically usually cause vasodilation in area of injection.
d. Vasoconstrictors such as epinephrine may counteract these effects on myocardium and vasculature.
4. Local Tissue Responses
a. Occasionally focal necrosis in skeletal muscle at injection site, decreased cell motility and delayed wound healing.
b. Tissue hypoxia may be produced by action of excessive amounts of vasoconstrictors.
Applegate's Classification for edentulous arches
ProsthodonticsApplegate's Classification is a system used to categorize edentulous
(toothless) arches in preparation for denture construction. The classification
is based on the amount and quality of the remaining alveolar ridge, the
relationship of the ridge to the residual ridges, and the presence of undercuts.
The system is primarily used in the context of complete denture prosthodontics
to determine the best approach for achieving retention, stability, and support
for the dentures.
Applegate's Classification for edentulous arches:
1. Class I: The alveolar ridge has a favorable arch form and sufficient height
and width to provide adequate support for a complete denture without the need
for extensive modifications. This is the ideal scenario for denture
construction.
2. Class II: The alveolar ridge has a favorable arch form but lacks the
necessary height or width to provide adequate support. This may require the use
of denture modifications such as flanges to enhance retention and support.
3. Class III: The ridge lacks both height and width, and there may be undercuts
or excessive resorption. In this case, additional procedures such as ridge
augmentation or the use of implants might be necessary to improve the foundation
for the denture.
4. Class IV: The ridge has an unfavorable arch form, often with significant
resorption, and may require extensive surgical procedures or adjuncts like
implants to achieve a functional and stable denture.
5. Class V: This is the most severe classification where the patient has no
residual alveolar ridge, possibly due to severe resorption, trauma, or surgical
removal. In such cases, the creation of a functional and stable denture may be
highly challenging and might necessitate advanced surgical procedures and/or the
use of alternative prosthetic options like over-dentures with implant support.
It's important to note that this classification is a guide, and individual
patient cases may present with a combination of features from different classes
or may require customized treatment plans based on unique anatomical and
functional requirements.
Antiarrhythmic Drugs-Class II Beta Blockers
Pharmacology
Class II Beta Blockers
Block SNS stimulation of beta receptors in the heart and decreasing risks of ventricular fibrillation
– Blockage of SA and ectopic pacemakers: decreases automaticity
– Blockage of AV increases the refractory period
- Increase AV nodal conduction ´
- Increase PR interval
- Reduce adrenergic activity
Treatment: Supraventricular tachycardia (AF, flutter, paroxysmal supraventricular tachycardia
– Acebutolol
– Esmolol
– Propanolol
Contraindications and Cautions
• Contraindicated in sinus bradycardia P < 45
• Cardiogenic shock, asthma or respiratory depression which could be made worse by the blocking of Beta receptors.
• Use cautiously in patients with diabetes and thyroid dysfunction, which could be altered by the blockade of Beta receptors
• Renal and hepatic dysfunction could alter the metabolism and excretion of these drugs.
Enflurane
Pharmacology
Enflurane (Ethrane) MAC 1.68, Blood/gas solubility ratio 1.9
- Extremely stable chemically.
- Less potent and less soluble in blood than is halothane.
- Respiratory depression is similar to that seen with halothane.
- Cardiac output is not depressed as much as with halothane, and the heart is not sensitized to catecholamines to the same degree.
- Enflurane produces better muscle relaxation than does halothane.
- Metabolism of this agent is very low. Inorganic fluoride is a product of metabolism, but is not sufficient to cause renal problems.
- Enflurane differs from halothane and the other inhalational anesthetic agents by causing seizures at doses slightly higher than those that induce anesthesia.
- Nausea appears to occur somewhat more often following Enflurane than it does following halothane.
Efficiency in Heat Sterilization
Oral and Maxillofacial SurgeryTests for Efficiency in Heat Sterilization – Sterilization Monitoring
Effective sterilization is crucial in healthcare settings to ensure the
safety of patients and the efficacy of medical instruments. Various monitoring
techniques are employed to evaluate the sterilization process, including
mechanical, chemical, and biological parameters. Here’s an overview of these
methods:
1. Mechanical Monitoring
Parameters Assessed:
Cycle Time: The duration of the sterilization
cycle.
Temperature: The temperature reached during the
sterilization process.
Pressure: The pressure maintained within the
sterilizer.
Methods:
Gauges and Displays: Observing the gauges or
digital displays on the sterilizer provides real-time data on the cycle
parameters.
Recording Devices: Some tabletop sterilizers are
equipped with recording devices that print out the cycle parameters for
each load.
Interpretation:
While correct readings indicate that the sterilization conditions
were likely met, incorrect readings can signal potential issues with the
sterilizer, necessitating further investigation.
2. Biological Monitoring
Spore Testing:
Biological Indicators: This involves using spore
strips or vials containing Geobacillus stearothermophilus,
a heat-resistant bacterium.
Frequency: Spore testing should be conducted weekly to
verify the proper functioning of the autoclave.
Interpretation: If the spores are killed after the
sterilization cycle, it confirms that the sterilization process was
effective.
3. Thermometric Testing
Thermocouple:
A thermocouple is used to measure temperature at two locations:
Inside a Test Pack: A thermocouple is placed
within a test pack of towels to assess the temperature reached in
the center of the load.
Chamber Drain: A second thermocouple measures
the temperature at the chamber drain.
Comparison: The readings from both locations are
compared to ensure that the temperature is adequate throughout the load.
4. Chemical Monitoring
Brown’s Test:
This test uses ampoules containing a chemical indicator that changes
color based on temperature.
Color Change: The indicator changes from red
through amber to green at a specific temperature, confirming that the
required temperature was reached.
Autoclave Tape:
Autoclave tape is printed with sensitive ink that changes color when
exposed to specific temperatures.
Bowie-Dick Test: This test is a specific
application of autoclave tape, where two strips are placed on a piece of
square paper and positioned in the center of the test pack.
Test Conditions: When subjected to a temperature
of 134°C for 3.5 minutes, uniform color development
along the strips indicates that steam has penetrated the load
effectively.