NEET MDS Synopsis
Non-barbiturate sedatives
Pharmacology
Non-barbiturate sedatives
1- Chloral hydrate is trichlorinated derivative of acetaldehyde that is converted to trichlorethanol in the body. It induces sleep in about 30 minutes and last up to 6 hr. it is irritant to GIT and produce unpleasant taste sensation.
2- Ramelteon melatonin receptors are thought to be involved in maintaining circadian rhythms underlying the sleep-wake cycle. Ramelteon is an agonist at MT1 and MT2 melatonin receptors , useful in patients with chronic insomnia with no rebound insomnia and
withdrawal symptoms
3- Ethanol (alcohol) it has antianxiety sedative effects but its toxic potential out ways its benefits.
Ethanol is a CNS depressant producing sedation and hypnosis with increasing dose.
Absorption of alcohol taken orally is rapid, it is highly lipid soluble, presence of food delayed its absorption, maximal blood concentration depend on total dose, sex, strength of the solution, the time over which it is taken, the presence of food and speed of metabolism.
Alcohol in the systemic circulation is oxidized in the liver principally 90% by alcohol dehydrogenase to acetaldehyde and then by acetaldehyde dehydrogenase to products that enter the citric cycle.
Alcohol metabolism by alcohol dehydrogenase follows first order kinetics in the smallest doses. Once the blood concentration exceeds about 10 mg/100 ml, the enzymatic processes are saturated and elimination rate no longer increases with increasing
concentration but become steady at 10-15 ml/ 1 hr. in occasional drinkers.
Thus alcohol is subject to dose dependant kinetics i.e. saturation or zero order kinetics.
Actions
- Ethanol acts on CNS in a manner similar to volatile anesthetic.
- It also enhances GABA so stimulating flux of chloride ions through ion channels.
- Other possible mode of action involve inhibition of Ca-channels and inhibition of excitatory NMDA receptors.
- Ethanol has non selective CNS depressant activity.
- It causes cutaneous vasodilatation, tachycardia and myocardial depression
Thumb Sucking
OrthodonticsThumb Sucking
According to Gellin, thumb sucking is defined as “the placement of the thumb
or one or more fingers in varying depth into the mouth.” This behavior is common
in infants and young children, serving as a self-soothing mechanism. However,
prolonged thumb sucking can lead to various dental and orthodontic issues.
Diagnosis of Thumb Sucking
1. History
Psychological Component: Assess any underlying
psychological factors that may contribute to the habit, such as anxiety or
stress.
Frequency, Intensity, and Duration: Gather information
on how often the child engages in thumb sucking, how intense the habit is,
and how long it has been occurring.
Feeding Patterns: Inquire about the child’s feeding
habits, including breastfeeding or bottle-feeding, as these can influence
thumb sucking behavior.
Parental Care: Evaluate the parenting style and care
provided to the child, as this can impact the development of habits.
Other Habits: Assess for the presence of other oral
habits, such as pacifier use or nail-biting, which may coexist with thumb
sucking.
2. Extraoral Examination
Digits:
Appearance: The fingers may appear reddened, exceptionally clean,
chapped, or exhibit short fingernails (often referred to as "dishpan
thumb").
Calluses: Fibrous, roughened calluses may be present on the superior
aspect of the finger.
Lips:
Upper Lip: May appear short and hypotonic (reduced muscle tone).
Lower Lip: Often hyperactive, showing increased movement or tension.
Facial Form Analysis:
Mandibular Retrusion: Check for any signs of the lower jaw being
positioned further back than normal.
Maxillary Protrusion: Assess for any forward positioning of the
upper jaw.
High Mandibular Plane Angle: Evaluate the angle of the mandible,
which may be increased due to the habit.
3. Intraoral Examination
Clinical Features:
Intraoral:
Labial Flaring: Maxillary anterior teeth may show labial flaring
due to the pressure from thumb sucking.
Lingual Collapse: Mandibular anterior teeth may exhibit lingual
collapse.
Increased Overjet: The distance between the upper and lower
incisors may be increased.
Hypotonic Upper Lip: The upper lip may show reduced muscle tone.
Hyperactive Lower Lip: The lower lip may be more active,
compensating for the upper lip.
Tongue Position: The tongue may be placed inferiorly, leading to
a posterior crossbite due to maxillary arch contraction.
High Palatal Vault: The shape of the palate may be altered,
resulting in a high palatal vault.
Extraoral:
Fungal Infection: There may be signs of fungal
infection on the thumb due to prolonged moisture exposure.
Thumb Nail Appearance: The thumb nail may exhibit a
dishpan appearance, indicating frequent moisture exposure and potential
damage.
Management of Thumb Sucking
1. Reminder Therapy
Description: This involves using reminders to help the
child become aware of their thumb sucking habit. Parents and caregivers can
gently remind the child to stop when they notice them sucking their thumb.
Positive reinforcement for not engaging in the habit can also be effective.
2. Mechanotherapy
Description: This approach involves using mechanical
devices or appliances to discourage thumb sucking. Some options include:
Thumb Guards: These are devices that fit over the
thumb to prevent sucking.
Palatal Crib: A fixed appliance that can be placed
in the mouth to make thumb sucking uncomfortable or difficult.
Behavioral Appliances: Appliances that create
discomfort when the child attempts to suck their thumb, thereby
discouraging the habit.
ZINC OXIDE AND EUGENOL
Dental Materials
ZINC OXIDE AND EUGENOL
This material is used for many dental purposes ranging from temporary restorative material to pulp capping. The material is composed of a powder that is basically zinc oxide and a liquid that is called eugenol.
Chemical Composition.
The powder must contain between 70 and 100 percent zinc oxide. The manufacturer may add hydrogenated resins to increase strength and zinc acetate to hasten the set.
Eugenol is usually derived from oil of cloves. The oil of cloves contains more eugenol (82 percent) Eugenol is an obtundent (pain-relieving agent). It is a clear liquid that gradually changes to amber when exposed to light.
Physical Properties.
This material relieves pain, makes tissue less sensitive to pain, is slightly antiseptic, and is low in thermal conductivity. It provides a good marginal seal when placed in tooth cavities. The crushing strength (compression strength) of pure zinc oxide and eugenol is about 2,000 psi, which is low in comparison to other cements. The addition of hydrogenated resin increases the crushing strength to 5,000 psi.
CLINICAL USES OF ZINC OXIDE AND EUGENOL
Treatment Restoration. It helps prevent pulpal irritation in carious teeth, lost restorations, advanced caries, or pulpitis. This dental material also exerts a palliative effect on the pulp.
Temporary Cementing Medium. Zinc oxide and eugenol is used as a temporary cementing medium for crowns, inlays, and fixed partial dentures.
Intermediate Base. Zinc oxide and eugenol is used as an intermediate base. This material provides insulation between metallic restorations and vital tooth structure. Because of the low crushing strength, its use is sometimes contraindicated.
Surgical Packing or Dressing. The surgical dressing applied and adapted over the gingival area after a gingivectomy. This dressing protects the area and makes the tissue less sensitive.
Keratinized Gingiva and Attached Gingiva
PeriodontologyKeratinized Gingiva and Attached Gingiva
The gingiva is an essential component of the periodontal tissues, providing
support and protection for the teeth. Understanding the characteristics of
keratinized gingiva, particularly attached gingiva, is crucial for assessing
periodontal health.
Keratinized Gingiva
Definition:
Keratinized gingiva refers to the gingival tissue that is covered by
a layer of keratinized epithelium, providing a protective barrier
against mechanical and microbial insults.
Areas of Keratinized Gingiva:
Attached Gingiva:
Extends from the gingival groove to the mucogingival junction.
Marginal Gingiva:
The free gingival margin that surrounds the teeth.
Hard Palate:
The roof of the mouth, which is also covered by keratinized
tissue.
Attached Gingiva
Location:
The attached gingiva is the portion of the gingiva that is firmly
bound to the underlying alveolar bone.
Width of Attached Gingiva:
The width of attached gingiva varies based on location and can
increase with age and in cases of supraerupted teeth.
Measurements:
Greatest Width:
Found in the incisor region:
Maxilla: 3.5 mm - 4.5 mm
Mandible: 3.3 mm - 3.9 mm
Narrowest Width:
Found in the posterior region:
Maxillary First Premolar: 1.9 mm
Mandibular First Premolar: 1.8 mm
Clinical Significance
Importance of Attached Gingiva:
The width of attached gingiva is important for periodontal health,
as it provides a buffer zone against mechanical forces and helps
maintain the integrity of the periodontal attachment.
Insufficient attached gingiva may lead to increased susceptibility
to periodontal disease and gingival recession.
Assessment:
Regular assessment of the width of attached gingiva is essential
during periodontal examinations to identify potential areas of concern
and to plan appropriate treatment strategies.
Maxillary Second Deciduous Molar.
Dental Anatomy
Maxillary Second Deciduous Molar.
-The notation is A or J.
-It looks like a first permanent molar
-There are three roots.
-Usually it has four well developed cusps.
-It is somwhat rhomboidal in outline.
-They often have the Carabelli trait.
- the shape the maxillary first permanent molar strongly resembles that of the adjacent deciduous second molar.
Extraction Patterns for Presurgical Orthodontics
Oral and Maxillofacial SurgeryExtraction Patterns for Presurgical Orthodontics
In orthodontics, the extraction pattern chosen can significantly influence
treatment outcomes, especially in presurgical orthodontics. The extraction
decisions differ based on the type of skeletal malocclusion, specifically Class
II and Class III malocclusions. Here’s an overview of
the extraction patterns for each type:
Skeletal Class II Malocclusion
General Approach:
In skeletal Class II malocclusion, the goal is to prepare the dental
arches for surgical correction, typically involving mandibular
advancement.
Extraction Recommendations:
No Maxillary Tooth Extraction: Avoid extracting
maxillary teeth, particularly the upper first premolars or any maxillary
teeth, to prevent over-retraction of the maxillary anterior teeth.
Over-retraction can compromise the planned mandibular advancement.
Lower First Premolar Extraction: Extraction of the
lower first premolars is recommended. This helps:
Level the arch.
Correct the proclination of the lower anterior teeth, allowing
for better alignment and preparation for surgery.
Skeletal Class III Malocclusion
General Approach:
In skeletal Class III malocclusion, the extraction pattern is
reversed to facilitate the surgical correction, often involving
maxillary advancement or mandibular setback.
Extraction Recommendations:
Upper First Premolar Extraction: Extracting the
upper first premolars is done to:
Correct the proclination of the upper anterior teeth, which is
essential for achieving proper alignment and aesthetics.
Lower Second Premolar Extraction: If additional
space is needed in the lower arch, the extraction of lower second
premolars is recommended. This helps:
Prevent over-retraction of the lower anterior teeth, maintaining
their position while allowing for necessary adjustments in the arch.
Augmentation of the Inferior Border of the Mandible
Oral and Maxillofacial SurgeryAugmentation of the Inferior Border of the Mandible
Mandibular augmentation refers to surgical procedures aimed
at increasing the height or contour of the mandible, particularly the inferior
border. This type of augmentation is often performed to improve the support for
dentures, enhance facial aesthetics, or correct deformities. Below is an
overview of the advantages and disadvantages of augmenting the inferior border
of the mandible.
Advantages of Inferior Border Augmentation
Preservation of the Vestibule:
The procedure does not obliterate the vestibule, allowing for the
immediate placement of an interim denture. This is particularly
beneficial for patients who require prosthetic support soon after
surgery.
No Change in Vertical Dimension:
Augmentation of the inferior border does not alter the vertical
dimension of the occlusion, which is crucial for maintaining proper bite
relationships and avoiding complications associated with changes in jaw
alignment.
Facilitation of Secondary Vestibuloplasty:
The procedure makes subsequent vestibuloplasty easier. By
maintaining the vestibular space, it allows for better access and
manipulation during any future surgical interventions aimed at deepening
the vestibule.
Protection of the Graft:
The graft used for augmentation is not subjected to direct
masticatory forces, reducing the risk of graft failure and promoting
better healing. This is particularly important in ensuring the longevity
and stability of the augmentation.
Disadvantages of Inferior Border Augmentation
Extraoral Scar:
The procedure typically involves an incision that can result in an
extraoral scar. This may be a cosmetic concern for some patients,
especially if the scar is prominent or does not heal well.
Potential Alteration of Facial Appearance:
If the submental and submandibular tissues are not initially loose,
there is a risk of altering the facial appearance. Tight or inelastic
tissues may lead to distortion or asymmetry postoperatively.
Limited Change in Superior Surface Shape:
The augmentation primarily affects the inferior border of the
mandible and may not significantly change the shape of the superior
surface of the mandible. This limitation can affect the overall contour
and aesthetics of the jawline.
Surgical Risks:
As with any surgical procedure, there are inherent risks, including
infection, bleeding, and complications related to anesthesia.
Additionally, there may be risks associated with the grafting material
used.
Glycogenolysis
Biochemistry
Glycogenolysis
Breakdown of glycogen to glucose is called glycogenolysis. The Breakdown of glycogen takes place in liver and muscle. In Liver , the end product of glycodgen breakdown is glucose where as in muscles the end product is Lactic acid Under the combined action of Phosphorylase (breaks only –α-(1,4) linkage )and Debranching enzymes (breaks only α-(1,6) linkage )glycogen is broken down to glucose.