NEET MDS Synopsis
Surgical Approaches in Oral and Maxillofacial Surgery
Oral and Maxillofacial SurgerySurgical Approaches in Oral and Maxillofacial Surgery
In the management of tumors and lesions in the oral and maxillofacial region,
various surgical approaches are employed based on the extent of the disease, the
involvement of surrounding structures, and the need for reconstruction. Below is
a detailed overview of the surgical techniques mentioned, along with their
indications and reconstruction options.
1. Marginal / Segmental / En Bloc Resection
Definition:
En Bloc Resection: This technique involves the complete
removal of a tumor along with a margin of healthy tissue, without disrupting
the continuity of the bone. It is often used for tumors that are
well-defined and localized.
Indications:
No Cortical Perforation: En bloc segmental resection is
indicated when there is no evidence of cortical bone perforation. This
allows for the removal of the tumor while preserving the structural
integrity of the surrounding bone.
Tumor Characteristics: This approach is suitable for
benign tumors or low-grade malignancies that have not invaded surrounding
tissues.
2. Partial Resection (Mandibulectomy)
Definition:
Mandibulectomy: This procedure involves the resection
of a portion of the mandible, typically performed when a tumor is present.
Indications:
Cortical Perforation: Mandibulectomy is indicated when
there is cortical perforation of the mandible. This means that the tumor has
invaded the cortical bone, necessitating a more extensive surgical approach.
Clearance Margin: A margin of at least 1 cm of
healthy bone is typically removed to ensure complete excision of the tumor
and reduce the risk of recurrence.
3. Total Resection (Hemimandibulectomy)
Definition:
Hemimandibulectomy: This procedure involves the
resection of one half of the mandible, including the associated soft
tissues.
Indications:
Perforation of Bone and Soft Tissue: Hemimandibulectomy
is indicated when there is both perforation of the bone and involvement of
the surrounding soft tissues. This is often seen in more aggressive tumors
or those that have metastasized.
Extensive Tumor Involvement: This approach is necessary
for tumors that cannot be adequately removed with less invasive techniques
due to their size or location.
4. Reconstruction
Following resection, reconstruction of the jaw is often necessary to restore
function and aesthetics. Several options are available for reconstruction:
a. Reconstruction Plate:
Description: A reconstruction plate is a rigid plate
made of titanium or other biocompatible materials that is used to stabilize
the bone after resection.
Indications: Used in cases where structural support is
needed to maintain the shape and function of the mandible.
b. K-wire:
Description: K-wires are thin, flexible wires used to
stabilize bone fragments during the healing process.
Indications: Often used in conjunction with other
reconstruction methods to provide additional support.
c. Titanium Mesh:
Description: Titanium mesh is a flexible mesh that can
be shaped to fit the contours of the jaw and provide support for soft tissue
and bone.
Indications: Used in cases where there is significant
bone loss and soft tissue coverage is required.
d. Rib Graft / Iliac Crest Graft:
Description: Autogenous bone grafts can be harvested
from the rib or iliac crest to reconstruct the mandible.
Indications: These grafts are used when significant
bone volume is needed for reconstruction, providing a biological scaffold
for new bone formation.
Intrinsic Muscles of the Tongue
AnatomyIntrinsic Muscles of the Tongue
The Superior Longitudinal Muscle of the Tongue
The muscle forms a thin layer deep to the mucous membrane on the dorsum of the tongue, running from its tip to its root.
It arises from the submucosal fibrous layer and the lingual septum and inserts mainly into the mucous membrane.
This muscle curls the tip and sides of the tongue superiorly, making the dorsum of the tongue concave.
The Inferior Longitudinal Muscle of the Tongue
This muscle consists of a narrow band close to the inferior surface of the tongue.
It extends from the tip to the root of the tongue.
Some of its fibres attach to the hyoid bone.
This muscle curls the tip of the tongue inferiorly, making the dorsum of the tongue convex.
The Transverse Muscle of the Tongue
This muscle lies deep to the superior longitudinal muscle.
It arises from the fibrous lingual septum and runs lateral to its right and left margins.
Its fibres are inserted into the submucosal fibrous tissue.
The transverse muscle narrows and increases the height of the tongue.
The Vertical Muscle of the Tongue
This muscle runs inferolaterally from the dorsum of the tongue.
It flattens and broadens the tongue.
Acting with the transverse muscle, it increases the length of the tongue.
Reaction- gypsum products
Dental Materials
Reaction
a. Calcium sulfate hemihydrate(one-half water) crystals dissolve and react with water
b. Calcium sulfate dihydrate(two waters) form and precipitate new crystals
c. Unreacted (excess) water is left between crystals in solid
Muscles Around the Nose
AnatomyMuscles Around the Nose
The Nasalis Muscle
This muscle consists of a transverse (compressor naris) and alar (dilator naris) parts.
It is supplied by the buccal branch of the facial nerve.
Titration of a weak acid with a strong base
Biochemistry
Titration of a weak acid with a strong base
• A weak acid is mostly in its conjugate acid form
• When strong base is added, it removes protons from the solution, more and more acid is in the conjugate base form, and the pH increases
• When the moles of base added equals half the total moles of acid, the weak acid and its conjugate base are in equal amounts. The ratio of CB / WA = 1 and according to the HH equation, pH = pKa + log(1) or pH = pKa.
• If more base is added, the conjugate base form becomes greater till the equivalance point when all of the acid is in the conjugate base form.
Endodontics - Pulp Pain & Diagnostics
Endodontics
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.
Infantile Osteomyelitis
Oral Pathology
Infantile Osteomyelitis
Osteomyelitis Maxillaries Neonatarum, Maxillitis of infancy
Osteomyelitis in the jaws of new born infants occurs almost exclusively in maxilla.
Etiology
Trauma – through break in mucosa cause during delivery.
Infection of maxillary sinus
Paunz & Ramon et al believe that disease caused through infection from the nose.
Hematogenous spread through streptococci & pneumococci
Clinical features
Fever, anorexia & intestinal disturbances.
swelling or redness below the inner canthus of the eye in lacrimal region.
Followed by marked edema of the eyelids on the affected side.
Next, alveolus & palate in region of first deciduous molar become swollen.
Pus discharge from affected sites
D/D for Infantile Osteomyelitis
Dacrocystitis neonatarum
Orbital cellulitis
Ophthalmia neonatarum
Infantile cortical hyperostosis
TREATMENT
Intravenous antibiotics, preferably penicillin.
Culture & sensitivity testing
Incision & drainage of fluctuant areas
Sequestrectomy
Supportive therapy