NEET MDS Synopsis
Osteogenesis in Oral Surgery
Oral and Maxillofacial SurgeryOsteogenesis in Oral Surgery
Osteogenesis refers to the process of bone formation, which
is crucial in various aspects of oral and maxillofacial surgery. This process is
particularly important in procedures such as dental implant placement, bone
grafting, and the treatment of bone defects or deformities.
Mechanisms of Osteogenesis
Osteogenesis occurs through two primary processes:
Intramembranous Ossification:
This process involves the direct formation of bone from mesenchymal
tissue without a cartilage intermediate. It is primarily responsible for
the formation of flat bones, such as the bones of the skull and the
mandible.
Steps:
Mesenchymal cells differentiate into osteoblasts (bone-forming
cells).
Osteoblasts secrete osteoid, which is the unmineralized bone
matrix.
The osteoid becomes mineralized, leading to the formation of
bone.
As osteoblasts become trapped in the matrix, they differentiate
into osteocytes (mature bone cells).
Endochondral Ossification:
This process involves the formation of bone from a cartilage model.
It is responsible for the development of long bones and the growth of
bones in length.
Steps:
Mesenchymal cells differentiate into chondrocytes (cartilage
cells) to form a cartilage model.
The cartilage model undergoes hypertrophy and calcification.
Blood vessels invade the calcified cartilage, bringing
osteoblasts that replace the cartilage with bone.
This process continues until the cartilage is fully replaced by
bone.
Types of Osteogenesis in Oral Surgery
In the context of oral surgery, osteogenesis can be classified into several
types based on the source of the bone and the method of bone formation:
Autogenous Osteogenesis:
Definition: Bone formation that occurs from the
patient’s own bone grafts.
Source: Bone is harvested from a donor site in the
same patient (e.g., the iliac crest, chin, or ramus of the mandible).
Advantages:
High biocompatibility and low risk of rejection.
Contains living cells and growth factors that promote healing
and bone formation.
Applications: Commonly used in bone grafting
procedures, such as sinus lifts, ridge augmentation, and implant
placement.
Allogeneic Osteogenesis:
Definition: Bone formation that occurs from bone
grafts taken from a different individual (cadaveric bone).
Source: Bone is obtained from a bone bank, where it
is processed and sterilized.
Advantages:
Reduces the need for a second surgical site for harvesting bone.
Can provide a larger volume of bone compared to autogenous
grafts.
Applications: Used in cases where significant bone
volume is required, such as large defects or reconstructions.
Xenogeneic Osteogenesis:
Definition: Bone formation that occurs from bone
grafts taken from a different species (e.g., bovine or porcine bone).
Source: Processed animal bone is used as a graft
material.
Advantages:
Readily available and can provide a scaffold for new bone
formation.
Often used in combination with autogenous bone to enhance
healing.
Applications: Commonly used in dental implant
procedures and bone augmentation.
Synthetic Osteogenesis:
Definition: Bone formation that occurs from
synthetic materials designed to mimic natural bone.
Source: Materials such as hydroxyapatite, calcium
phosphate, or bioactive glass.
Advantages:
No risk of disease transmission or rejection.
Can be engineered to have specific properties that promote bone
growth.
Applications: Used in various bone grafting
procedures, particularly in cases where autogenous or allogeneic grafts
are not feasible.
Factors Influencing Osteogenesis
Several factors can influence the process of osteogenesis in oral surgery:
Biological Factors:
Growth Factors: Proteins such as bone morphogenetic
proteins (BMPs) play a crucial role in promoting osteogenesis.
Cellular Activity: The presence of osteoblasts,
osteoclasts, and mesenchymal stem cells is essential for bone formation
and remodeling.
Mechanical Factors:
Stability: The stability of the graft site is
critical for successful osteogenesis. Rigid fixation can enhance bone
healing.
Loading: Mechanical loading can stimulate bone
formation and remodeling.
Environmental Factors:
Oxygen Supply: Adequate blood supply is essential
for delivering nutrients and oxygen to the bone healing site.
pH and Temperature: The local environment can
affect cellular activity and the healing process.
Carisolv
Conservative DentistryCarisolvCarisolv is a dental caries removal system that offers a unique approach to
the treatment of carious dentin. It differs from traditional methods, such as
Caridex, by utilizing amino acids and a lower concentration of sodium
hypochlorite. Below is an overview of its components, mechanism of action,
application process, and advantages.
1. Components of Carisolv
A. Red Gel (Solution A)
Composition:
Amino Acids: Contains 0.1 M of three amino acids:
I-Glutamic Acid
I-Leucine
I-Lysine
Sodium Hydroxide (NaOH): Used to adjust pH.
Sodium Hypochlorite (NaOCl): Present at a lower
concentration compared to Caridex.
Erythrosine: A dye that provides color to the gel,
aiding in visualization during application.
Purified Water: Used as a solvent.
B. Clear Liquid (Solution B)
Composition:
Sodium Hypochlorite (NaOCl): Contains 0.5% NaOCl
w/v, which contributes to the antimicrobial properties of the solution.
C. Storage and Preparation
Temperature: The two separate gels are stored at 48°C
before use and are allowed to return to room temperature prior to
application.
2. Mechanism of Action
Softening Carious Dentin: Carisolv is designed to
soften carious dentin by chemically disrupting denatured collagen within the
affected tissue.
Collagen Disruption: The amino acids in the formulation
play a crucial role in breaking down the collagen matrix, making it easier
to remove the softened carious dentin.
Scraping Away: After the dentin is softened, it is
removed using specially designed hand instruments, allowing for precise and
effective caries removal.
3. pH and Application Time
Resultant pH: The pH of Carisolv is approximately 11,
which is alkaline and conducive to the softening process.
Application Time: The recommended application time for
Carisolv is between 30 to 60 seconds, allowing for quick
treatment of carious lesions.
4. Advantages
Minimally Invasive: Carisolv offers a minimally
invasive approach to caries removal, preserving healthy tooth structure
while effectively treating carious dentin.
Reduced Need for Rotary Instruments: The chemical
action of Carisolv reduces the reliance on traditional rotary instruments,
which can be beneficial for patients with anxiety or those requiring a
gentler approach.
Visualization: The presence of erythrosine allows for
better visualization of the treated area, helping clinicians ensure complete
removal of carious tissue.
Hepatitis D and E virus
General Pathology
Hepatitis D virus—can only infect cells previously infected with hepatitis B.
Delta hepatitis (HDV) is associated with a 35-nm RNA virus composed of a delta antigen-bearing core surrounded by HBV's Ag coat;
HDV requires HBV for replication.
Delta hepatitis can cause quiescent HBV states to suddenly worsened . Its transmission is the same as that of HBV.
Hepatitis E virus—a high mortality rate in infected pregnant women.
Hepatitis E (HEV) is caused by a single-stranded RNA virus. The disease is typically self-limited and does not evolve into chronic hepatitis; it may, however, be cholestatic.
Pregnant women may develop fulminant disease.
Transmission is by the fecal oral route.
HEV occurs mainly in India, Nepal, Pakistan, and Southeast Asia.
Griseofulvin
Pharmacology
Griseofulvin
Griseofulvin is an antifungal drug. It is used both in animals and in humans, to treat ringworm infections of the skin and nails. It is derived from the mold Penicillium griseofulvum.
It is administered orally.
Microbes causing Food poisoning
Microbiology
Infectious
Salmonella [poultry, meat, eggs]
Salmonella enteritidis
Vibrio parahaemolyticus [seafood]
Enterohemorrhagic E. coli
Other diarrhetic E. coli
Clostridium perfringens [reheated meat]
Yersinia enterocolitica
Campylobacter jejuni/coli
Cholera vibrio [seafood]
Shigella
Typhus bacilli, paratyphoid bacilli
Vibrio vulnificus [seafood]
Toxic
Staphylococcus aureus [meats, mayo, custard]
Clostridium botulinum [canned foods]
Bacillus cereus [reheated rice]
Viral food poisoning
Norovirus
Sapovirus
Viral hepatitis A
Viral hepatitis E
Protozoa
Cryptosporidium
Cyclospora
Quinolone
Pharmacology
Quinolone
Quinolones and fluoroquinolones form a group of broad-spectrum antibiotics. They are derived from nalidixic acid.
Fluoroquinolone antibiotics are highly potent and considered relatively safe.
MOA : Quinolones act by inhibiting the bacterial DNA gyrase enzyme. This way they inhibit nucleic acid synthesis and act bacteriocidically.
Drugs :Nalidixic acid, Ciprofloxacin , Levofloxacin, Norfloxacin ,Ofloxacin, Moxifloxacin , Trovafloxacin
Bruxism
OrthodonticsBruxism
Bruxism is the involuntary grinding or clenching of teeth,
often occurring during sleep (nocturnal bruxism) or while awake (awake bruxism).
It can lead to various dental and health issues, including tooth wear, jaw pain,
and temporomandibular joint (TMJ) disorders.
Etiology
Central Nervous System (CNS):
Bruxism has been observed in individuals with neurological
conditions such as cerebral palsy and mental retardation, suggesting a
CNS component to the phenomenon.
Psychological Factors:
Emotional disturbances such as anxiety, stress, aggression, and
feelings of hunger can contribute to the tendency to grind teeth.
Psychological stressors are often linked to increased muscle tension and
bruxism.
Occlusal Discrepancy:
Improper interdigitation of teeth, such as malocclusion or
misalignment, can lead to bruxism as the body attempts to find a
comfortable bite.
Systemic Factors:
Nutritional deficiencies, particularly magnesium (Mg²⁺) deficiency,
have been associated with bruxism. Magnesium plays a role in muscle
function and relaxation.
Genetic Factors:
There may be a hereditary component to bruxism, with a family
history of the condition increasing the likelihood of its occurrence.
Occupational Factors:
High-stress occupations or activities, such as being an
overenthusiastic student or participating in competitive sports, can
lead to increased clenching and grinding of teeth.
Clinical Features
Tooth Wear: Increased wear on the occlusal surfaces of
teeth, leading to flattened or worn-down teeth.
Jaw Pain: Discomfort or pain in the jaw muscles,
particularly in the masseter and temporalis muscles.
TMJ Disorders: Symptoms such as clicking, popping, or
locking of the jaw, as well as pain in the TMJ area.
Headaches: Tension-type headaches or migraines may
occur due to muscle tension associated with bruxism.
Facial Pain: Generalized facial pain or discomfort,
particularly around the jaw and temples.
Gum Recession: Increased risk of gum recession and
periodontal issues due to excessive force on the teeth.
Management
Adjunctive Therapy:
Psychotherapy: Aimed at reducing emotional
disturbances and stress that may contribute to bruxism. Techniques may
include cognitive-behavioral therapy (CBT) or relaxation techniques.
Pain Management:
Ethyl Chloride: A topical anesthetic that can
be injected into the TMJ area to alleviate pain and discomfort.
Occlusal Therapy:
Occlusal Adjustment: Adjusting the occlusion to
improve the bite and reduce bruxism.
Splints:
Volcanite Splints: These are custom-made
occlusal splints that cover the occlusal surfaces of all teeth. They
help reduce muscle tone and protect the teeth from wear.
Night Guards: Similar to splints, night guards
are worn during sleep to prevent grinding and clenching.
Restorative Treatment: Addressing any existing
dental issues, such as cavities or misaligned teeth, to improve overall
dental health.
Pharmacological Management:
Vapo Coolant: Ethyl chloride can be used for pain
relief in the TMJ area.
Local Anesthesia: Direct injection of local
anesthetics into the TMJ can provide temporary relief from pain.
Muscle Relaxants: Medications such as muscle
tranquilizers or sedatives may be prescribed to help reduce muscle
tension and promote relaxation.
Basic characteristics of enzymes
Biochemistry
The basic characteristics of enzymes includes
(i) Almost all the enzymes are proteins and they follow the physical and chemical reactions of proteins (ii) Enzymes are sensitive and labile to heat
(iii) Enzymes are water soluble
(iv) Enzymes could be precipitated by protein precipitating agents such as ammonium sulfate and trichloroacetic acid.