NEET MDS Synopsis
Marsupialization
Oral and Maxillofacial SurgeryMarsupialization
Marsupialization, also known as decompression, is a surgical
procedure used primarily to treat cystic lesions, particularly odontogenic
cysts, by creating a surgical window in the wall of the cyst. This technique
aims to reduce intracystic pressure, promote the shrinkage of the cyst, and
encourage bone fill in the surrounding area.
Key Features of Marsupialization
Indication:
Marsupialization is indicated for large cystic lesions that are not
amenable to complete excision due to their size, location, or proximity
to vital structures. It is commonly used for:
Odontogenic keratocysts
Dentigerous cysts
Radicular cysts
Other large cystic lesions in the jaw
Surgical Technique:
Creation of a Surgical Window:
The procedure begins with the creation of a window in the wall
of the cyst. This is typically done through an intraoral approach,
where an incision is made in the mucosa overlying the cyst.
Evacuation of Cystic Content:
The cystic contents are evacuated, which helps to decrease the
intracystic pressure. This reduction in pressure is crucial for
promoting the shrinkage of the cyst and facilitating bone fill.
Suturing the Cystic Lining:
The remaining cystic lining is sutured to the edge of the oral
mucosa. This can be done using continuous sutures or interrupted
sutures, depending on the surgeon's preference and the specific
clinical situation.
Benefits:
Pressure Reduction: By decreasing the intracystic
pressure, marsupialization can lead to the gradual reduction in the size
of the cyst.
Bone Regeneration: The procedure promotes bone fill
in the area previously occupied by the cyst, which can help restore
normal anatomy and function.
Minimally Invasive: Compared to complete cyst
excision, marsupialization is less invasive and can be performed with
less morbidity.
Postoperative Care:
Patients may experience some discomfort and swelling following the
procedure, which can be managed with analgesics.
Regular follow-up appointments are necessary to monitor the healing
process and assess the reduction in cyst size.
Oral hygiene is crucial to prevent infection at the surgical site.
Outcomes:
Marsupialization can be an effective treatment for large cystic
lesions, leading to significant reduction in size and promoting bone
regeneration. In some cases, if the cyst does not resolve completely,
further treatment options, including complete excision, may be
considered.
Sliding Osseous Genioplasty
Oral and Maxillofacial SurgerySliding Osseous Genioplasty
Sliding osseous genioplasty is a surgical technique designed
to enhance the projection of the chin, thereby improving facial aesthetics. This
procedure is particularly advantageous for patients with retrogathia,
where the chin is positioned further back than normal, and who typically present
with Class I occlusion (normal bite relationship) without
significant dentofacial deformities.
Indications for Sliding Osseous Genioplasty
Aesthetic Chin Surgery:
Most patients seeking this procedure do not have severe dentofacial
deformities. They desire increased chin projection to achieve better
facial balance and aesthetics.
Retrogathia:
Patients with a receding chin can significantly benefit from sliding
osseous genioplasty, as it allows for the forward repositioning of the
chin.
Procedure Overview
Sliding Osseous Genioplasty involves several key steps:
Surgical Technique:
Incision: The procedure can be performed through an
intraoral incision (inside the mouth) or an extraoral incision (under
the chin) to access the chin bone (mandibular symphysis).
Bone Mobilization: A horizontal osteotomy (cut) is
made in the chin bone to create a movable segment. This allows the
surgeon to slide the bone segment forward to increase chin projection.
Fixation: Once the desired position is achieved,
the bone segment is secured in place using plates and screws or other
fixation methods to maintain stability during the healing process.
Versatility:
Shorter and Longer Advancements: The technique can
be tailored to achieve both shorter and longer advancements of the chin,
depending on the patient's aesthetic goals.
Vertical Height Alterations: Sliding osseous
genioplasty is particularly effective for making vertical height
adjustments to the chin, allowing for a customized approach to facial
contouring.
Recovery
Postoperative Care:
Patients may experience swelling, bruising, and discomfort following
the procedure. Pain relief medications are typically prescribed to
manage discomfort.
A soft diet is often recommended during the initial recovery phase
to minimize strain on the surgical site.
Follow-Up Appointments:
Regular follow-up visits are necessary to monitor healing, assess
the alignment of the chin, and ensure that there are no complications.
The surgeon will evaluate the aesthetic outcome and make any
necessary adjustments to the postoperative care plan.
Pernicious anaemia
General Pathology
Pernicious anaemia
The special features are:
Due to intrinsic factor deficiency
Gastric atrophy with histamine fast achlorhydria
Genetic basis (racial distribution and blood group A).
Seen with auto immune disorders.
Antibodies to parietal cells and to intrinsic factors are seen
FUNCTIONS OF PERIODONTIUM
Dental Anatomy
FUNCTIONS OF PERIODONTIUM
Tooth support
Shock absorber
Sensory (vibrations appreciated in the middle ear/reflex jaw opening)
Alveolar bone
Dental Anatomy
As root and cementum formation begin, bone is created in the adjacent area. Throughout the body, cells that form bone are called osteoblasts. In the case of alveolar bone, these osteoblast cells form from the dental follicle. Similar to the formation of primary cementum, collagen fibers are created on the surface nearest the tooth, and they remain there until attaching to periodontal ligaments.
Like any other bone in the human body, alveolar bone is modified throughout life. Osteoblasts create bone and osteoclasts destroy it, especially if force is placed on a tooth. As is the case when movement of teeth is attempted through orthodontics, an area of bone under compressive force from a tooth moving toward it has a high osteoclast level, resulting in bone resorption. An area of bone receiving tension from periodontal ligaments attached to a tooth moving away from it has a high number of osteoblasts, resulting in bone formation.
Mouth Breathing
OrthodonticsMouth Breathing
Mouth breathing is a condition where an individual breathes
primarily through the mouth instead of the nose. This habit can lead to various
dental, facial, and health issues, particularly in children. The etiology of
mouth breathing is often related to nasal obstruction, and it can have
significant clinical features and consequences.
Etiology
Nasal Obstruction: Approximately 85% of mouth breathers
suffer from some degree of nasal obstruction, which can be caused by:
Allergies: Allergic rhinitis can lead to
inflammation and blockage of the nasal passages.
Enlarged Adenoids: Hypertrophy of the adenoids can
obstruct airflow through the nasal passages.
Deviated Septum: A structural abnormality in the
nasal septum can impede airflow.
Chronic Sinusitis: Inflammation of the sinuses can
lead to nasal congestion and obstruction.
Clinical Features
Facial Characteristics:
Adenoid Facies: A characteristic appearance
associated with chronic mouth breathing, including:
Long, narrow face.
Narrow nose and nasal passage.
Short upper lip.
Nose tipped superiorly.
Expressionless or "flat" facial appearance.
Dental Effects (Intraoral):
Protrusion of Maxillary Incisors: The anterior
teeth may become protruded due to the altered position of the tongue and
lips.
High Palatal Vault: The shape of the palate may be
altered, leading to a high and narrow palatal vault.
Increased Incidence of Caries: Mouth breathers are
more prone to dental caries due to dry oral conditions and reduced
saliva flow.
Chronic Marginal Gingivitis: Inflammation of the
gums can occur due to poor oral hygiene and dry mouth.
Management
Symptomatic Treatment:
Gingival Health: The gingiva of mouth breathers
should be restored to normal health. Coating the gingiva with petroleum
jelly can help maintain moisture and protect the tissues.
Addressing Obstruction: If nasal or pharyngeal
obstruction has been diagnosed, surgical intervention may be necessary
to remove the cause (e.g., adenoidectomy, septoplasty).
Elimination of the Cause:
Identifying and treating the underlying cause of nasal obstruction
is crucial. This may involve medical management of allergies or surgical
correction of anatomical issues.
Interception of the Habit:
Physical Exercise: Encouraging physical activity
can help improve overall respiratory function and promote nasal
breathing.
Lip Exercises: Exercises to strengthen the lip
muscles can help encourage lip closure and discourage mouth breathing.
Oral Screen: An oral screen or similar appliance
can be used to promote nasal breathing by preventing the mouth from
remaining open.
Endodontics - Pulp Pain & Diagnostics
Endodontics
Lipids
PhysiologyLipids:
about 40% of the dry mass of a typical cell
composed largely of carbon & hydrogen
generally insoluble in water
involved mainly with long-term energy storage; other functions are as structural components (as in the case of phospholipids that are the major building block in cell membranes) and as "messengers" (hormones) that play roles in communications within and between cells
Subclasses include:
Triglycerides - consist of one glycerol molecule + 3 fatty acids (e.g., stearic acid in the diagram below). Fatty acids typically consist of chains of 16 or 18 carbons (plus lots of hydrogens).
phospholipids - Composed of 2 fatty acids, glycerol, phosphate and polar groups , phosphate group (-PO4) substitutes for one fatty acid & these lipids are an important component of cell membranes
steroids - have 4 rings- cholesterol, some hormones, found in membranes include testosterone, estrogen, & cholesterol