NEET MDS Synopsis
The Protein Buffer Systems
Biochemistry
The Protein Buffer Systems
The protein buffers are very important in the plasma and the intracellular fluids but their concentration is very low in cerebrospinal fluid, lymph and interstitial fluids.
The proteins exist as anions serving as conjugate bases (Pr − ) at the blood pH 7.4 and form conjugate acids (HPr) accepting H+ . They have the capacity to buffer some H2CO3 in the blood.
Anterior bite plate
OrthodonticsAnterior bite plate is an orthodontic appliance used
primarily to manage various dental issues, particularly those related to
occlusion and alignment of the anterior teeth. It is a removable appliance that
is placed in the mouth to help correct bite discrepancies, improve dental
function, and protect the teeth from wear.
Indications for Use
Anterior Crossbite:
An anterior bite plate can help correct an anterior crossbite by
repositioning the maxillary incisors in relation to the mandibular
incisors.
Open Bite:
It can be used to help close an anterior open bite by providing a
surface for the anterior teeth to occlude against, encouraging proper
alignment.
Bruxism:
The appliance can protect the anterior teeth from wear caused by
grinding or clenching, acting as a barrier between the upper and lower
teeth.
Space Maintenance:
In cases where anterior teeth have been lost or extracted, an
anterior bite plate can help maintain space for future dental work or
the eruption of permanent teeth.
Facilitation of Orthodontic Treatment:
It can be used as part of a comprehensive orthodontic treatment plan
to help achieve desired tooth movements and improve overall occlusion.
Design and Features
Material: Anterior bite plates are typically made from
acrylic or thermoplastic materials, which are durable and can be easily
adjusted.
Shape: The appliance is designed to cover the anterior
teeth, providing a flat occlusal surface for the upper and lower teeth to
meet.
Retention: The bite plate is custom-fitted to the
patient’s dental arch to ensure comfort and stability during use.
Mechanism of Action
Repositioning Teeth: The anterior bite plate can help
reposition the anterior teeth by providing a surface that encourages proper
occlusion and alignment.
Distributing Forces: It helps distribute occlusal
forces evenly across the anterior teeth, reducing the risk of localized wear
or damage.
Encouraging Proper Function: By providing a stable
occlusal surface, the bite plate encourages proper chewing and speaking
functions.
Management and Care
Patient Compliance: For the anterior bite plate to be
effective, patients must wear it as prescribed by their orthodontist. This
may involve wearing it during the day, at night, or both, depending on the
specific treatment goals.
Hygiene: Patients should maintain good oral hygiene and
clean the bite plate regularly to prevent plaque buildup and maintain oral
health.
Regular Check-Ups: Follow-up appointments with the
orthodontist are essential to monitor progress and make any necessary
adjustments to the appliance.
Dental trauma types in endodontics
EndodonticsIn endodontics, dental trauma often results in the luxation of teeth, which
is the displacement of a tooth from its normal position in the alveolus (the
bone socket that holds the tooth). There are several types of luxation injuries,
each with different endodontic implications. Here are the main types of dental
luxation:
1. Concussion: A tooth is injured but not displaced from its socket. The
periodontal ligament (PDL) is compressed and may experience hemorrhage. The
tooth is usually not loose and does not require repositioning. However, it can
be tender to percussion and may exhibit some mobility. The pulp may remain
vital, but it can become inflamed or necrotic due to the trauma.
2. Subluxation: The tooth is partially displaced but remains in the socket. It
shows increased mobility in all directions but can be repositioned with minimal
resistance. The PDL is stretched and may be damaged, leading to pulpal and
periodontal issues. Endodontic treatment is often not necessary unless symptoms
of pulp damage arise.
3. Lateral luxation: The tooth is displaced in a horizontal direction and may be
pushed towards the adjacent teeth. The PDL is stretched and possibly torn. The
tooth may be pushed out of alignment or into an incorrect position in the arch.
Prompt repositioning and splinting are crucial. The pulp can be injured, and the
likelihood of endodontic treatment may increase.
4. Intrusion: The tooth is pushed into the alveolar bone, either partially or
completely. This can cause significant damage to the PDL and the surrounding
bone tissue. The tooth may appear shorter than its neighbors. The pulp is often
traumatized and can die if not treated quickly. Endodontic treatment is usually
required after repositioning and stabilization.
5. Extrusion: The tooth is partially displaced out of its socket. The PDL is
stretched and sometimes torn. The tooth appears longer than its neighbors. The
pulp is frequently exposed, which increases the risk of infection and necrosis.
Repositioning and endodontic treatment are typically necessary.
6. Avulsion: The tooth is completely knocked out of its socket. The PDL is
completely severed, and the tooth may have associated soft tissue injuries. Time
is of the essence in these cases. If the tooth can be replanted within 30
minutes and properly managed, the chances of saving the pulp are higher.
Endodontic treatment is usually needed, with the possibility of a root canal or
revascularization.
7. Inverse luxation: This is a rare type of luxation where the tooth is
displaced upwards into the alveolar bone. The tooth is pushed into the bone,
which can cause severe damage to the PDL and surrounding tissues. Endodontic
treatment is often necessary.
8. Dystopia: Although not a true luxation, it's worth mentioning that a tooth
can be displaced during eruption. This can cause the tooth to emerge in an
abnormal position. Endodontic treatment may be necessary if the tooth does not
respond to orthodontic treatment or if the displacement causes pain or
infection.
The endodontic management of luxated teeth varies depending on the severity of
the injury and the condition of the pulp. Treatments can range from simple
monitoring to root canal therapy, apicoectomy, or even tooth extraction in
severe cases. The goal is always to preserve the tooth and prevent further
complications.
Apexogenesis
Pedodontics
Apexogenesis
Apexogenesis is a vital pulp therapy procedure aimed at promoting the
continued physiological development and formation of the root end of an immature
tooth. This procedure is particularly relevant in pediatric dentistry,
where the goal is to preserve the vitality of the dental pulp in young patients,
allowing for normal root development and maturation of the tooth.
Indications for Apexogenesis
Apexogenesis is typically indicated in cases where the pulp is still vital
but has been exposed due to caries, trauma, or other factors. The procedure is
designed to maintain the health of the pulp tissue, thereby facilitating the
ongoing development of the root structure. It is most commonly performed on
immature permanent teeth, where the root has not yet fully formed.
Materials Used
Mineral Trioxide Aggregate (MTA) is frequently used in apexogenesis
procedures. MTA is a biocompatible material known for its excellent
sealing properties and ability to promote healing. It serves as a
barrier to protect the pulp and encourages the formation of a calcified barrier
at the root apex, facilitating continued root development.
Signs of Success
The most important indicator of successful apexogenesis is the
continuous completion of the root apex. This means that as the pulp
remains vital and healthy, the root continues to grow and mature, ultimately
achieving the appropriate length and thickness necessary for functional dental
health.
Contraindications
While apexogenesis can be a highly effective treatment for preserving the
vitality of the pulp in young patients, it is generally contraindicated in
children with serious systemic illnesses, such as leukemia or cancer. In these
cases, the risks associated with the procedure may outweigh the potential
benefits, and alternative treatment options may be considered.
Liver Diseases
General Pathology
1. Pyogenic liver abscesses may be caused by E. coli, Klebsiella, Streptococcus, Staphylococcus, Bacteroides, Pseudomonas, and fungi.
Parasitic infections
1. Schistosomiasis is caused by different organisms in different parts of the world.
a. Clinical features include splenomegaly, portal hypertension, and ascites. Lesions are caused by the immune response to ova.
2. Amebiasis is caused by Entamoeba histolytica.
a. Clinical features include bloody diarrhea, pain, fever, jaundice, and hepatomegaly.
Drug-induced liver damage may be caused by agents that are direct hepatotoxins, such as carbon tetrachloride, acetaminophen, methotrexate, anabolic steroids, and oral contraceptive pills.
Speech
Anatomyo English: all speech sounds produced by making exhaled air audible
o Two ways of producing sound
at larynx
further up in vocal tract (tongue, lips)
o How to produce sound at larynx
changes in breathing: regulate airstream from lungs to atmosphere by changing movements of vocal folds, pharynx, soft-palate, tongue, lips and jaws
• inhalation: take in greater volume more quickly, abduct folds
• expiration: variable force; use muscles of inhalation to control rate of expiration, adduct
How to vibrate vocal cords
• NOT rhythmic contraction of laryngeal muscles: would be impossible b/c frequenceies of virbration
• Changes in air pressure cause vibrations
o Adduct folds increase in subglottal pressure force folds apart folds sucked back together (Bernouilli effect)
• The vibration of vocal cords disturbs airareas of low pressure (rarefaction) alternating with areas of high pressure (compression)
• Changes in pressure sound at ears
• Sine waves
o Changes in amplitudes: loudness
o Changes in frequency: pitch
o Normal sounds have fundamental frequency, overtones or harmonics
o Mass of folds: critical in voice
Low pitch of lion’s roar: due to massive fibrous pad that forms part of vocal cords
Men: more massive vocal cords
Larger foldsslow vibrationdeeper voice
o Producing vowels and constants
Most vowels are “voiced”: vocal folds produce sounds
Consonants: can be “voiced” (Z) or “non-voiced” (S)
• Use higher regions of vocal tract to control by stopping, restricting airflow from vocal folds; use lips, teethaperiodic sound
o Vocal folds and resonators emphasize and deemphasize certain frequencies
Never hear sounds produced at vocal foldsevery sound changed by passage thru vocal tract: sinuses/resonating chambers
Howling monkeys: large hyoid bonepowerful resonator
o Age-related changes in voice
Infant larynx is smaller, different proportions
• Arytenoids are proportionately larger
• Smaller vocal apparatushigher pitch
• Larynx sits higher easier to breathe thru nose
Abrupt change in larynx at pubertycan’t control voice
Older adult: normal degenerative changes in lamina propria, ossification of thyroid cartilagechanges in fundamental frequency
Lose your voice vocal fold are irritated
• Can’t adduct foldsair escapes
o Singing v. speaking
Singing: greater thoracic pressure and uneven breathing with changes in resonators
o Whispering
Intercartilaginous portions of vocal folds: open to allow air to escapelesser subglottal pressureslittle vibration of foldslittle tonal quality, low volume
o Falsetto
Allowing only part of vocal folds to vibrate
Increase range by training which part of vocal folds to vibrate
o Colds
Mucus secretions add mass to folds—decrease in pitch, can’t adduct folds as well
o Surgeryscars, fibrotic changes can interfere with voice
Dental amalgam -properties
Dental Materials
PROPERTY
INGREDIENT
Silver
Tin
Copper
Zinc
Strength
Increases
Durability
Increases
Hardness
Increases
Expansion
Increases
Decreases
Increases
Flow
Decreases
Increases
Decreases
Color
Imparts
Setting time
Decreases
Increases
Decreases
Workability
Increases
Increases
PHARMACOLOGY OF VASOCONSTRICTORS
Pharmacology
PHARMACOLOGY OF VASOCONSTRICTORS
All local anesthetics currently used in dentistry today produce some degree of vasodilatation. This
characteristic results in the increased vascularity of the injected site and results in a shorter duration of local
anesthetic action due enhanced uptake of the local anesthetic into the bloodstream.
- Using a “chemical tourniquet” to prolong the effect of local anesthetics
- The vasoconstrictive action of epinephrine reduces uptake of local anesthetic resulting in a significant increase in the duration of local anesthetic action.
- the addition of vasoconstrictors in local anesthetic solutions will:
1. Prolong the effect of the local anesthetic
2. Increase the depth of anesthesia
3. Reduces the plasma concentration of the local anesthetic
4. Reduces the incidence of systemic toxicity
5. Reduces bleeding at surgical site
Local anesthetics containing epinephrine produce:
1. Localized
VASOCONSTRICTION MEDIATED BY ALPHA RECEPTOR ACTIVATION
i. Hemostasis at surgical site
ii. Ischemia of localized tissue
2. Systemic
HEART
i. Increased heart rate (β1)
ii. Increased force and rate of contraction (β 1)
iii. Increased cardiac output
iv. Increases oxygen demand
v. Dilation of coronary arteries
vi. Decreases threshold for arrhythmias
LUNGS
i. Bronchodilation (β2 )
SKELETAL MUSCLE
i. Predominately vasodilation (fight or flight response) (β 2 )
CNS
i. Minimal direct effect due to difficulty in crossing the blood-brain barrier. Most effects on the CNS are manifestations of the vasoconstrictor on other organs such as the heart.
Concentrations of vasoconstrictors
1. Epinephrine The most commonly used epinephrine dilution in dentistry today is 1:100000. However it appears that a 1:200000 concentration is comparable in effect to the 1:100000 concentration.
2. Levonordefrin Levonordefrin is a synthetic compound very similar in structure to epinephrine. It is the only alternate choice of vasoconstrictor to epinephrine. It is prepared as a 1:20000 (0.05mg/ml)(50 mcg/ml) concentration with 2 % mepivacaine.
Cardiovascular considerations
The plasma concentration of epinephrine in a patient at rest is 39 pg/ml.1 The injection of 1 cartridge of lidocaine 1:100000 epinephrine intraorally results in a doubling of the plasma concentration of epinephrine.
The administration of 15 mcg of epinephrine increased heart rate an average of 25 beats/min with some individuals experiencing an increase of 70 beats/min.
Clinical considerations
It is well documented that reduced amounts of epinephrine should be administered to patients with:
HEART DISEASE (ANGINA HISTORYOF MI)
POORLY CONTROLLED HIGH BLOOD PRESSURE
It is generally accepted that the dose of epinephrine should be limited to 0.04 mg (40 mcg) for patients that have these medical diagnoses