NEET MDS Synopsis
OCCLUSION AND DENTAL DEVELOPMENT-Stages-pre-dentition period
Dental Anatomy
The pre-dentition period.
-This is from birth to six months.
-At this stage, there are no teeth. Clinically, the infant is edentulous
-Both jaws undergo rapid growth; the growth is in three planes of space: downward, forward, and laterally (to the side). Forward growth for the mandible is greater.
-The maxillary and mandibular alveolar processes are not well developed at birth.
-occasionally, there is a neonatal tooth present at birth. It is a supernumerary and is often lost soon after birth.
-At birth, bulges in the developing alveoli precede eruption of the deciduous teeth. At birth, the molar pads can touch.
Kinins
Pharmacology
Kinins
Peptide that are mediated in the inflammation.
Action of kinin:
On CVS: vasodilatation in the kidneys, heart, intestine, skin, and liver. It is 10 times active than histamine as vasodilator.
On exocrine and endocrine glands: kinin modulate the tone of pancreas and salivery glands and help regulate GIT motility, also affect the transport of water and electrolytes, glucose and amino acids through epithelial cell transport.
Oral Habits
PedodonticsClassification of Oral Habits
Oral habits can be classified based on various criteria, including their
nature, impact, and the underlying motivations for the behavior. Below is a
detailed classification of oral habits:
1. Based on Nature of the Habit
Obsessive Habits (Deep Rooted):
International or Meaningful:
Examples: Nail biting, digit sucking, lip biting.
Masochistic (Self-Inflicting):
Examples: Gingival stripping (damaging the gums).
Unintentional (Empty):
Examples: Abnormal pillowing, chin propping.
Non-Obsessive Habits (Easily Learned and Dropped):
Functional Habits:
Examples: Mouth breathing, tongue thrusting, bruxism (teeth
grinding).
2. Based on Impact
Useful Habits:
Habits that may have a positive or neutral effect on oral health.
Harmful Habits:
Habits that can lead to dental issues, such as malocclusion,
gingival damage, or tooth wear.
3. Based on Author Classifications
James (1923):
a) Useful Habits
b) Harmful Habits
Kingsley (1958):
a) Functional Oral Habits
b) Muscular Habits
c) Combined Habits
Morris and Bohanna (1969):
a) Pressure Habits
b) Non-Pressure Habits
c) Biting Habits
Klein (1971):
a) Empty Habits
b) Meaningful Habits
Finn (1987):
I. a) Compulsive Habits
b) Non-Compulsive Habits
II. a) Primary Habits
4. Based on Functionality
Functional Habits:
Habits that serve a purpose, such as aiding in speech or feeding.
Dysfunctional Habits:
Habits that disrupt normal oral function or lead to negative
consequences.
FUNCTIONS OF PERIODONTIUM
Dental Anatomy
FUNCTIONS OF PERIODONTIUM
Tooth support
Shock absorber
Sensory (vibrations appreciated in the middle ear/reflex jaw opening)
The Lateral Wall of the Orbit
AnatomyThe Lateral Wall of the Orbit
This wall is thick, particularly its posterior part, which separates the orbit from the middle cranial fossa.
The lateral wall is formed by the frontal process of the zygomatic bone and the greater wing of the sphenoid bone.
Anteriorly, the lateral wall lies between the orbit and the temporal fossa.
The lateral wall is partially separated from the roof by the superior orbital fissure.
SPIROCHETAL DISEASE -Syphilis
General Pathology
SPIROCHETAL DISEASE
Syphilis
A contagious systemic disease caused by the spirochete Treponema pallidum, characterized by sequential clinical stages and by years of latency.
ACQUIRED SYPHILIS
T. pallidum is a delicate spiral organism about 0.25 µm wide and from 5 to 20 µm long, identified by characteristic morphology and motility with a darkfield microscope or fluorescent techniques
In acquired syphilis, T. pallidum enters through the mucous membranes or skin, reaches the regional lymph nodes within hours, and rapidly disseminates throughout the body. In all stages of disease, perivascular infiltration of lymphocytes, plasma cells, and, later, fibroblasts causes swelling and proliferation of the endothelium of the smaller blood vessels, leading to endarteritis obliterans.
In late syphilis, T. pallidum elicits a granulomatous-like (gummatous) reaction causing masses, ulcerations, and necrosis. Inflammation may subside despite progressive damage, especially in the cardiovascular and central nervous systems.
The CNS is invaded early in the infection. During the secondary stage of the disease, > 30% of patients have abnormal CSF and may have symptoms of meningitis
Symptoms, Signs, and Course
The incubation period of primary syphilis can vary from 1 to 13 wk but is usually from 3 to 4 wk. The disease may present at any stage and long after the initial infection
Primary stage: The primary lesion, or chancre generally evolves and heals within 4 to 8 wk in untreated patients. After inoculation, a red papule quickly erodes to form a painless ulcer with an indurated base that, when abraded, exudes a clear serum containing numerous spirochetes
The regional lymph nodes usually enlarge painlessly and are firm, discrete, and nontender. Chancres occur on the penis, anus, and rectum in men and on the vulva, cervix, and perineum in women. Chancres may also occur on the lips or the oropharyngeal or anogenital mucous membranes.
Secondary stage: Cutaneous rashes usually appear within 6 to 12 wk after infection and are most florid after 3 to 4 mo.
Frequently, generalized, nontender, firm, discrete lymphadenopathy and hepatosplenomegaly are palpable. Over 80% of patients have mucocutaneous lesions, 50% have generalized lymphadenopathy, and about 10% have lesions of the eyes (uveitis), bones (periostitis), joints, meninges, kidneys (glomerulitis), liver, and spleen.
Acute syphilitic meningitis may develop, with headache, neck stiffness, cranial nerve lesions, deafness, and, occasionally, papilledema.
Condyloma lata--hypertrophic, flattened, dull pink or gray papules at the mucocutaneous junctions and in moist areas of the skin--are extremely infectious. Hair often falls out in patches, leaving a moth-eaten appearance (alopecia areata).
Latent stage
In the early latent period (< 2 yr after infection), infectious mucocutaneous relapses may occur, but after 2 yr contagious lesions rarely develop, and the patient appears normal. About 1/3 of untreated persons develop late syphilis
Late or tertiary stage: Lesions may be clinically described as (1) benign tertiary syphilis of the skin, bone, and viscera, (2) cardiovascular syphilis, or (3) neurosyphilis.
The typical lesion is a gumma, an inflammatory mass that evolves to necrosis and fibrosis and that is frequently localized but may diffusely infiltrate an organ or tissue
Benign tertiary syphilis of the bones results in either periostitis with bone formation or osteitis with destructive lesions causing a deep, boring pain, characteristically worse at night. A lump or swelling may be palpable.
Cardiovascular syphilis: A dilated, usually fusiform aneurysm of the ascending or transverse aorta, narrowing of the coronary ostia, or aortic valvular insufficiency usually appears 10 to 25 yr after the initial infection
Neurosyphilis
In meningovascular neurosyphilis, brain involvement is signaled by headache, dizziness, poor concentration, lassitude, insomnia, neck stiffness, and blurred vision. Mental confusion, epileptiform attacks, papilledema, aphasia, and mono- or hemiplegia may also occur
Diagnosis:
Two classes of serologic tests for syphilis (STS) aid in diagnosing syphilis and other related treponemal diseases: screening, nontreponemal tests using lipoid antigens detect syphilitic reagin and include the Venereal Disease Research Laboratory (VDRL) and the rapid plasma reagin (RPR) tests. Specific treponemal tests detect antitreponemal antibodies and include fluorescent treponemal antibody absorption (FTA-ABS) test, microhemagglutination assay for antibodies to T. pallidum (MHA-TP), and Treponema pallidum hemagglutination assay (TPHA).
In darkfield microscopy, light is directed obliquely through the slide so that rays striking the spirochetes cause them to appear as bright, motile, narrow coils against a dark background
Prosthodontics
Bevels are the angulation which is made by 2 surfaces of a
prepared tooth which is other than 90 degrees. Bevels are given at various
angles depending on the type of material used for restoration and the purpose
the material serves.
Any abrupt incline between the 2 surfaces of a prepared tooth or between the
cavity wall and the Cavo surface margins in the prepared cavity
Bevels are the variations which are created during tooth preparation or cavity
preparation to help in increased retention and to prevent marginal leakage.
It is seen that in Bevels Occlusal cavosurface margin needs to be 40 degrees
which seals and protects enamel margins from leakage and the Gingival Cavo
surface margin should be 30 degrees to remove the unsupported enamel rods and
produce a sliding fit or lap joint useful in burnishing gold.
Types or Classification of Bevels based on the Surface they are placed
on:
Classification of Bevels based on the two factors – Based on the shape and
tissue surface involved and Based on the surface they are placed on –
Based on the shape and tissue surface involved:
1. Partial or Ultra short bevel
2. Short Bevel
3. Long Bevel
4. Full Bevel
5. Counter Bevel
6. Reverse / Minnesota Bevel
Partial or Ultra Short Bevel:
Beveling which involves less than 2/3rd of the Enamel thickness. This is not
used in Cast restorations except to trim unsupported enamel rods from the cavity
borders.
Short Bevel:
Entire enamel wall is included in this type of Bevel without involving the
Dentin. This bevel is used mostly with Class I alloys specially for type 1 and
2. It is used in Cast Gold restoration
Long Bevel:
Entire Enamel and 1/2 Dentin is included in the Bevel preparation. Long Bevel is
most frequently used bevel for the first 3 classes of Cast metals. Internal
boxed- up resistance and retention features of the preparation are preserved
with Long Bevel.
Full Bevel:
Complete Enamel and Dentinal walls of the cavity wall or floor are included in
this Bevel. It is well reproduced by all four classes of cast alloys, internal
resistance and retention features are lost in full bevel. Its use is avoided
except in cases where it is impossible to use any other form of bevel .
Counter Bevel:
It is used only when capping cusps to protect and support them, opposite to an
axial cavity wall , on the facial or lingual surface of the tooth, which will
have a gingival inclination facially or lingually.
There is another type of Bevel called the Minnesota Bevel or the Reverse Bevel,
this bevel as the name suggest is opposite to what the normal bevel is and it is
mainly used to improve retention in any cavity preparation
If we do not use functional Cusp Bevel –
1. It Can cause a thin area or perforation of the restoration borders
2. May result in over contouring and poor occlusion
3. Over inclination of the buccal surface will destroy excessive tooth structure
reducing retention
Based on the surface they are placed on:
1. Gingival bevel
2. Hollow ground bevel
3. Occlusal bevel or Functional cusp bevel
Gingival bevel:
1. Removal of Unsupported Enamel Rods.
2. Bevel results in 30° angle at the gingival margin that is burnishable because
of its angular design.
3. A lap sliding fit is produced at the gingival margin which help in improving
the fit of casting in this region.
4. Inlay preparations include of two types of bevel Occlusal bevel Gingival
bevel
Hollow Ground (concave) Bevel: Hollow ground bevel allows more
space for bulk of cast metal, a design feature needed in special preparations to
improve material’s castability retention and better resistance to stresses.
These bevels are ideal for class IV and V cast materials. This is actually an
exaggerated chamfer or a concave beveled shoulder which involves teeth greater
than chamfer and less than a beveled shoulder. The buccal slopes of the lingual
cusps and the lingual slope of the buccal cusps should be hollow ground to a
depth of at least 1 mm.
Occlusal Bevel:
1. Bevels satisfy the requirements for ideal cavity walls.
2. They are the flexible extensions of a cavity preparation , allowing the
inclusion of surface defects , supplementary grooves , or other areas on the
tooth surface.
3. Bevels require minimum tooth involvement and do not sacrifice the resistance
and retention for the restoration
4. Bevels create obtuse-angled marginal tooth structure, which is bulkiest and
the strongest configuration of any marginal tooth anatomy, and produce an acute
angled marginal cast alloy substance which allows smooth burnishing for alloy.
Functional cusp Bevel:
An integral part of occlusal reduction is the functional cusp bevel. A wide
bevel placed on the functional cusp provides space for an adequate bulk of metal
in an area of heavy occlusal contact.
Gross Features of the Tongue
AnatomyGross Features of the Tongue
The dorsum of the tongue is divided by a V-shaped sulcus terminalis into anterior oral (presulcal) and posterior pharyngeal (postsulcal) parts.
The apex of the V is posterior and the two limbs diverge anteriorly.
The oral part forms about 2/3 of the tongue and the pharyngeal part forms about 1/3.
Oral Part of the Tongue
This part is freely movable, but it is loosely attached to the floor of the mouth by the lingual frenulum.
On each side of the frenulum is a deep lingual vein, visible as a blue line.
It begins at the tip of the tongue and runs posteriorly.
All the veins on one side of the tongue unite at the posterior border of the hyoglossus muscle to form the lingual vein, which joins the facial vein or the internal jugular vein.
On the dorsum of the oral part of the tongue is a median groove.
This groove represents the site of fusion of the distal tongue buds during embryonic development.
The Lingual Papillae and Taste Buds
The filiform papillae (L. filum, thread) are numerous, rough, and thread-like.
They are arranged in rows parallel to the sulcus terminalis.
The fungiform papillae are small and mushroom-shaped.
They usually appear are pink or red spots.
The vallate (circumvallate) papillae are surrounded by a deep, circular trench (trough), the walls of which are studded with taste buds.
The foliate papillae are small lateral folds of lingual mucosa that are poorly formed in humans.
The vallate, foliate and most of the fungiform papillae contain taste receptors, which are located in the taste buds.
The Pharyngeal Part of the Tongue
This part lies posterior to the sulcus terminalis and palatoglossal arches.
Its mucous membrane has no papillae.
The underlying nodules of lymphoid tissue give this part of the tongue a cobblestone appearance.
The lymphoid nodules (lingual follicles) are collectively known as the lingual tonsil.