NEET MDS Synopsis
Enophthalmos
Oral and Maxillofacial SurgeryEnophthalmos
Enophthalmos is a condition characterized by the inward
sinking of the eye into the orbit (the bony socket that holds the eye). It is
often a troublesome consequence of fractures involving the zygomatic complex
(the cheekbone area).
Causes of Enophthalmos
Enophthalmos can occur due to several factors following an injury:
Loss of Orbital Volume:
There may be a decrease in the volume of the contents within the
orbit, which can happen if soft tissues herniate into the maxillary
sinus or through the medial wall of the orbit.
Fractures of the Orbital Walls:
Fractures in the walls of the orbit can increase the volume of the
bony orbit. This can occur with lateral and inferior displacement of the
zygoma or disruption of the inferior and lateral orbital walls. A
quantitative CT scan can help visualize these changes.
Loss of Ligament Support:
The ligaments that support the eye may be damaged, contributing to
the sinking of the eye.
Post-Traumatic Changes:
After an injury, fibrosis (the formation of excess fibrous
connective tissue), scar contraction, and fat atrophy (loss of fat in
the orbit) can occur, leading to enophthalmos.
Combination of Factors:
Often, enophthalmos results from a combination of the above factors.
Diagnosis
Acute Cases: In the early stages after an injury,
diagnosing enophthalmos can be challenging. This is because swelling (edema)
of the surrounding soft tissues can create a false appearance of
enophthalmos, making it seem like the eye is more sunken than it actually
is.
Mental Attitude of Patients for Complete Dentures
Prosthodontics
The mental attitude of patients towards complete dentures plays a significant
role in the success of their treatment. Understanding these attitudes can help
dental professionals tailor their approach to meet the needs and expectations of
their patients. Here are the four primary mental attitudes that patients may
exhibit:
1. Philosophical (Ideal Attitude)
Characteristics:
Accepts the dentist's judgment without question.
Exhibits a rational, sensible, calm, and composed disposition.
Open to discussing treatment options and understands the importance
of oral health.
Implications for Treatment:
This type of patient is likely to follow the dentist's
recommendations and cooperate throughout the treatment process.
They are more likely to have realistic expectations and be satisfied
with the outcomes.
2. Indifferent
Characteristics:
Shows little concern for their oral health.
Seeks treatment primarily due to pressure from family or friends.
Requires additional time and education to understand the importance
of dental care.
Their attitude can be discouraging to dentists, as they may not
fully engage in the treatment process.
Implications for Treatment:
Dentists may need to invest extra effort in educating these patients
about the benefits of complete dentures and the importance of oral
health.
Building rapport and trust is essential to encourage a more
proactive attitude towards treatment.
3. Critical/Exacting
Characteristics:
Has previously had multiple sets of complete dentures and tends to
find fault with everything.
Often has high expectations and may be overly critical of the
treatment process.
May require medical consultation due to previous experiences or
health concerns.
Implications for Treatment:
Dentists should be prepared to address specific concerns and provide
detailed explanations about the treatment plan.
It is important to manage expectations and ensure that the patient
understands the limitations and possibilities of denture treatment.
4. Skeptical/Hysterical
Characteristics:
Has had negative experiences with previous treatments, leading to
doubt and skepticism about the current treatment.
Often presents with poor oral health, resorbed ridges, and other
unfavorable conditions.
May exhibit anxiety or hysteria regarding dental procedures.
Implications for Treatment:
Building trust and confidence is crucial for these patients.
Dentists should take the time to listen to their concerns and provide
reassurance.
A gentle and empathetic approach is necessary to help alleviate
fears and encourage cooperation.
It may be beneficial to involve them in the decision-making process
to empower them and reduce anxiety.
Tuberculosis
General Pathology
Tuberculosis
Causative organism
-Mycobacterium tuberculosis
-Strict aerobe
-Pathogenic strains
-hominis, bovis, avium, murine& cold blooded vertebrate strain
Koch’s bacillus
-small slender, rod like bacillus, 4umnon-motile, aerobic -high lipid content
-divides every 16 to 20 hours, an extremely slow rate
-stains very weakly Gram-positive or does not retain dye due to the high lipid & mycolicacid content of its cell wall
-can withstand weak disinfectant and survive in a dry state for weeks.
Demonstrated by
-ZiehlNeelsenstaining
-Fluorescent dye method
-Culture in LJ media
-Guinea pig inoculation
Modes of transmission
Inhalation , Ingestion, Inoculation , Transplacental
Route Spread
Local , Lymphatic , Haematogenous , By natural passages,
Pathogenesis
- Anti‐mycobacterial CMI, confers resistance to bacteria → dev. of HS to tubercular Ag
- Bacilli enters macrophages
- Replicates in phagosomeby blocking fusion of phagosome& lysosome, continues for 3 weeks →bacteremiabut asymptomatic
- After 3 wks, T helper response is mounted by IL‐12 produced by macrophages
- T cells produce IFN, activates macrophages → bactericidal activity, structural changes
- Macrophages secrete TNF→ macrophage recruitment, granuloma& necrosis
Fate of granuloma
- Caseousmaterial undergo liquefaction---cold abscess
- Bones, joints, lymph nodes & epididymis---sinuses are formed & sinus tract lined by tuberculousgranulation tissue
- Dystrophic calcification
Types of TB
1. Primary Pulmonary TB
2. secondary TB (miliary, fibrocaseous, cavitary)
3. Extra-pulmonary TB (bone, joints, renal, adrenal, skin… )
Primary TB
Infection in an individual who has not been previously infected or immunised
Primary complex
Sites
-lungs, hilarlymph nodes
-tonsils, cervical lymph nodes
-small intestine, mesenteric lymph nodes
Primary TB
In the lung, Ghon’scomplex has 3 components:
1. Pulmonary component -Inhalation of airborne droplet ~ 3 microns.
-Bacilli locate in the subpleuralmid zone of lung
-Brief acute inflammation –neutrophils.
-5-6 days-invoke granulomaformation.
-2 to 8 weeks –healing –single round ;1-1.5 cm-Ghon focus.
2. Lymphatic vessel component
3. Lymph node component
Fate of primary tuberculosis
- Lesions heal by fibrosis, may undergo calcification, ossification
-a few viable bacilli may remain in these areas
-bacteria goes into a dormant state, as long as the person's immune system remains active
- Progressive primary tuberculosis: primary focus continues to grow & caseousmaterial disseminated to other parts of lung
- Primary miliarytuberculosis: bacilli may enter circulation through erosion of blood vessel
- Progressive secondary tuberculosis: healed lesions are reactivated, in children & in lower resistance
Secondary tuberculosis
-Post-primary/ reinfection/ chronic TB
-Occurs in immunized individuals.
-Infection acquired from
-endogenous source/ reactivation
-exogenous source/ reinfection
Reactivation
-when immune system is depressed
-Common in low prevalence areas.
-Occurs in 10-15% of patients
-Slowly progressive (several months)
Re-infection
-when large innoculum of bacteria occurs
-In areas with increased personal contact
Secondary TB
-Sites-Lungs 1-2 cm apical consolidation with caseation
-Other sites -tonsils, pharynx, larynx, small intestine & skin
Fate of secondary tuberculosis
•Heal with fibrous scarring & calcification
•Progressive secondary pulmonary tuberculosis:
-fibrocaseoustuberculosis
-tuberculouscaseouspneumonia
-miliarytuberculosis
Complications:
a) aneurysm of arteries–hemoptysis
b) bronchopleuralfistula
c) tuberculousempyema
MiliaryTB
• Millet like, yellowish, firm areas without caseation
• Extensive spread through lympho-hematogenousroute
• Low immunity
• Pulmonary involvement via pulmonary artery
• Systemic through pulmonary vein:
-LN: scrofula, most common
-kidney, spleen, adrenal, brain, bone marrow
Signs and Symptoms of Active TB
• Pulmonary-cough, hemoptysis, dyspnea
• Systemic:
• fever
• night sweats
• loss of appetite
• weight loss
• chest pain,fatigue
•If symptoms persist for at least 2 weeks, evaluate for possible TB infection
Diagnosis
•Sputum-Ziehl Neelsen stain –10,000 bacilli, 60% sensitivity
-release of acid-fast bacilli from cavities intermittent.
-3 negative smears : low infectivity
•Culture most sensitive and specific test.
-Conventional Lowenstein Jensen media-10 wks.
-Liquid culture: 2 weeks
•Automated techniques within days
should only be performed by experienced laboratories (10 bacilli)
•PPD for clinical activity / exposure sometime in life
•X-ray chest
•FNAC
PPD Tuberculin Testing
- Read after 72 hours.
- Indurationsize -5-10 mm
- Does not d/s b/w active and latent infection
- False +: atypical mycobacterium
- False -: malnutrition, HD, viral, overwhelming infection, immunosuppression
- BCG gives + result.
Tuberculosis Atypical mycobacteria
- Photochromogens---M.kansasii
- Scotochromogens---M.scrofulaceum
- Non-chromogens---M.avium-intracellulare
- Rapid growers---M.fortuitum, M.chelonei
5 patterns of disease
- Pulmonary—M.kansasii, M.avium-intracellulare
- Lymphadenitis----M.avium-intracellulare, M.scrofulaceum
- Ulcerated skin lesions----M.ulcerans, M.marinum
- Abscess----M.fortuitum, M.chelonei
- Bacteraemias----M.avium-intracellulare as in AIDS
Naber’s Probe and Furcation Involvement
Periodontology Naber’s Probe and Furcation Involvement
Furcation involvement is a critical aspect of periodontal disease that
affects the prognosis of teeth with multiple roots. Naber’s probe is a
specialized instrument designed to assess furcation areas, allowing clinicians
to determine the extent of periodontal attachment loss and the condition of the
furcation. This lecture will cover the use of Naber’s probe, the classification
of furcation involvement, and the clinical significance of these
classifications.
Naber’s Probe
Description: Naber’s probe is a curved, blunt-ended
instrument specifically designed for probing furcation areas. Its unique
shape allows for horizontal probing, which is essential for accurately
assessing the anatomy of multi-rooted teeth.
Usage: The probe is inserted horizontally into the
furcation area to evaluate the extent of periodontal involvement. The
clinician can feel the anatomical fluting between the roots, which aids in
determining the classification of furcation involvement.
Classification of Furcation Involvement
Furcation involvement is classified into four main classes using Naber’s
probe:
Class I:
Description: The furcation can be probed to a depth
of 3 mm.
Clinical Findings: The probe can feel the
anatomical fluting between the roots, but it cannot engage the roof of
the furcation.
Significance: Indicates early furcation involvement
with minimal attachment loss.
Class II:
Description: The furcation can be probed to a depth
greater than 3 mm, but not through and through.
Clinical Findings: This class represents a range
between Class I and Class III, where there is partial loss of attachment
but not complete penetration through the furcation.
Significance: Indicates moderate furcation
involvement that may require intervention.
Class III:
Description: The furcation can be completely probed
through and through.
Clinical Findings: The probe passes from one
furcation to the other, indicating significant loss of periodontal
support.
Significance: Represents advanced furcation
involvement, often associated with a poor prognosis for the affected
tooth.
Class III+:
Description: The probe can go halfway across the
tooth.
Clinical Findings: Similar to Class III, but with
partial obstruction or remaining tissue.
Significance: Indicates severe furcation
involvement with a significant loss of attachment.
Class IV:
Description: Clinically, the examiner can see
through the furcation.
Clinical Findings: There is complete loss of tissue
covering the furcation, making it visible upon examination.
Significance: Indicates the most severe form of
furcation involvement, often leading to tooth mobility and extraction.
Measurement Technique
Measurement Reference: Measurements are taken from an
imaginary tangent connecting the prominences of the root surfaces of both
roots. This provides a consistent reference point for assessing the depth of
furcation involvement.
Clinical Significance
Prognosis: The classification of furcation involvement
is crucial for determining the prognosis of multi-rooted teeth. Higher
classes of furcation involvement generally indicate a poorer prognosis and
may necessitate more aggressive treatment strategies.
Treatment Planning: Understanding the extent of
furcation involvement helps clinicians develop appropriate treatment plans,
which may include scaling and root planing, surgical intervention, or
extraction.
Monitoring: Regular assessment of furcation involvement
using Naber’s probe can help monitor disease progression and the
effectiveness of periodontal therapy.
Treatment modifications to consider if there are concerns regarding vasoconstrictors
Pharmacology
Treatment modifications to consider if there are concerns regarding vasoconstrictors
- Monitor blood pressure and heart rate preoperatively
- Minimize administration of epinephrine or levonordefrin
- Monitor blood pressure and heart rate 5 min after injection
- May re-administer epinephrine or levonordefrin if blood pressure and heart rate are stable
- Continue to monitor as required
- Consider limiting epinephrine to 0.04 mg, levonordefrin to 0.2 mg
- Avoid epinephrine 1:50,000
- Never use epinephrine-impregnated retraction cord
Classification of Cementum
Dental Anatomy
Classification of Cementum
Embryologically
Primary and secondary
2. According to cellular component
Acellular: Thin, Amorphous, First layer to seal the dentin tubules
Cellular: Thick, Better structure, Apical surface
Layers of cellular and acellular cementum alternate (randomly)
3. Based on the origin of the collagenous matrix
Extrinsic
Intrinsic
Mixed
4. Combined classification
a. Primary acellular intinsic fiber cementum
b. Primary acellualar extrinsic fiber cementum
c. Secondary cellular intrinsic fiber cementum
d. Secondary cellular mixed fiber cementum
e. Acellular afibrillar cementum
5. Depending on the location and patterning
Intermediate and mixed stratified cementum
Participating Cells
Cementoblasts
Active
Cells are round, plump with basophilic cytoplasm (rough endoplasmic reticulum)
Inactive
Cells have little cytoplasm
Cementocytes
Cementocyte lacuna
cementocyte canaliculus
Cells have fewer organelles compared to cementoblasts. They are found in lacunae and have numerous processes toward the periodontal ligament. Eventually they die due to avascularity
Cementicles
a) free
b) attached
c) embedded
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.
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.