NEET MDS Synopsis
Solution Liners
Dental Materials
Solution Liners (Varnishes)
Applications
o Enamel and dentin lining for amalgam restorations
o Enamel and dentin lining for cast restorations that are used with non adhesive cements
o Coating over materials that are moisture sensitive during setting
Components of copal resin varnish
o 90% solvent mixture (e.g., chloroform, acetone, and alcohol)
o 10% dissolved copal resin
Reaction
Varnish sets physically by drying → Solvent loss occurs in 5 to 15 seconds (a film forms the same way as drying fingernail polish)
Manipulation
Apply thin coat over dentin. enamel. And margins of the cavity preparation → Dry lightly with air for 5 seconds Apply a second thin coat → Final thickness is 1 to 5 µ.m
Properties
o Physical
Electrically insulating barrier that prevents shocks. Too thin to be thermally insulating. Decreases degree of percolation attributable to thermal expansion
o Chemical
Forms temporary barrier that prevents microleakage into dentinal tubules until secondary dentin formation occurs. Decreases initial tendency for electrochemical corrosion
o Mechanical
Very weak and brittle film that has limited lifetime
Film adheres to smear layer
Spruing Technique
Dental Materials
Spruing Technique:
Direct Spruing:
The flow of the molten metal is straight(direct) from the casting crucible to pattern area in the ring. Even with the ball reservoir, the Spruing method is still direct. A basic weakness of direct Spruing is the potential for suck-back porosity at the junction of restoration and the Sprue.
Indirect Spruing:
Molten alloy does not flow directly from the casting crucible into the pattern area, instead the alloy takes a circuitous (indirect) route. The connector (or runner) bar is often used to which the wax pattern Sprue formers area attached. Indirect Spruing offers advantages such as greater reliability & predictability in casting plus enhanced control of solidification shrinkage .The Connector bar is often referred to as a “reservoir .
Armamentarium :
1 . Sprue
2 . Sticky wax
3 . Rubber crucible former
4 . Casting ring
5 . Pattern cleaner
6 . Scalpel blade & Forceps
7 . Bunsen burner
Orthodontic MCQ 1
Orthodontics
1. An adult patient with a Class II molar relationship and a cephalometric ANB angle of 2 degrees has which type of malocclusion?
1. Class II dental malocclusion
2. Class II skeletal malocclusion
3. Class I dental malocclusion
4. Class II skeletal malocclusion
ans 1. The molars are Class II but the skeletal relationship described by a normal ANB measurement is normal, so the malocclusion is dental
in origin.
2. Which of the following reactions is least likely to be observed during orthodontic treatment?
1. Root resorption
2. Devitalization of teeth that are moved
3. Mobility of teeth that are moved
4. Development of occlusal interferences
Ans 2. Root resorption is common during orthodontic treatment, although lesions often repair on the root surface. Mobility of teeth is also common as the PDL reorganizes and widens during tooth movement. It is uncommon for teeth to become devitalized as a result of orthodontic movement unless they have also been substantially compromised by injury or infection.
3. A 7-year-old has a 4-mm maxillary midline diastema. Which of the following should be done?
1. Brackets should be placed to close it.
2. A radiograph should be taken to rule out the presence of a supernumerary tooth.
3. Nothing should be done. It will close on its own.
4. Nothing should be done. Treatment should be deferred until the rest of the permanent dentition erupts.
Ans. 2. When a large diastema greater than 2 mm is present, it will probably not close on its own. Diagnostic tests, such as a radiograph, should be accomplished to rule out the presence of a supernumerary tooth, usually a mesiodens.
4. When Class III elastics are used, the maxillary first molars will _____.
1. Move distally and intrude
2. Move mesially and extrude
3. Move mesially and intrude
4. Move only mesially; there will be no movement in the vertical direction
ans 2. Class III elastics are worn from the maxillary first molars to the mandibular canines. The force system created by Class III elastics will produce mesial movement and extrusion of the maxillary first molars.
5. Ideally, Orthodontic traction to pull an impacted tooth to line of arch should begin
1. at 2-3 months post surgically
2. As soon as possible after surgery
3. After a waiting period of at least1.5 months
4. Only the method of traction is critical, not the time
ans 2
Mechanical approaches for aligning unerupted teeth. Orthodontic traction to pull an unerupted tooth toward the line of the arch
should begin as soon as possible after surgery Ideally a fixed orthodontic appliance should already be in place before the unerupted tooth is exposed, so that orthodontic force can be applied immediately. If this is not practical, active orthodontic
movement should being no later than 2 or 3 weeks post-surgically.
Gow-Gates Technique for Mandibular Anesthesia
Oral and Maxillofacial SurgeryGow-Gates Technique for Mandibular Anesthesia
The Gow-Gates technique is a well-established method for
achieving effective anesthesia of the mandibular teeth and associated soft
tissues. Developed by George Albert Edwards Gow-Gates, this technique is known
for its high success rate in providing sensory anesthesia to the entire
distribution of the mandibular nerve (V3).
Overview
Challenges in Mandibular Anesthesia: Achieving
successful anesthesia in the mandible is often more difficult than in the
maxilla due to:
Greater anatomical variation in the mandible.
The need for deeper penetration of soft tissues.
Success Rate: Gow-Gates reported an astonishing success
rate of approximately 99% in his experienced hands, making
it a reliable choice for dental practitioners.
Anesthesia Coverage
The Gow-Gates technique provides sensory anesthesia to the following nerves:
Inferior Alveolar Nerve
Lingual Nerve
Mylohyoid Nerve
Mental Nerve
Incisive Nerve
Auriculotemporal Nerve
Buccal Nerve
This comprehensive coverage makes it particularly useful for procedures
involving multiple mandibular teeth.
Technique
Equipment
Needle: A 25- or 27-gauge long needle is
recommended for this technique.
Injection Site and Target Area
Area of Insertion:
The injection is performed on the mucous membrane on
the mesial aspect of the mandibular ramus.
The insertion point is located on a line drawn from the intertragic
notch to the corner of the mouth, just distal
to the maxillary second molar.
Target Area:
The target for the injection is the lateral side of the
condylar neck, just below the insertion of the lateral
pterygoid muscle.
Landmarks
Extraoral Landmarks:
Lower Border of the Tragus: This serves as a reference
point. The center of the external auditory meatus is the ideal landmark, but
since it is concealed by the tragus, the lower border is used as a visual
aid.
Corner of the Mouth: This helps in aligning the
injection site.
Intraoral Landmarks:
Height of Injection: The needle tip should be placed
just below the mesiopalatal cusp of the maxillary second
molar to establish the correct height for the injection.
Penetration Point: The needle should penetrate the soft
tissues just distal to the maxillary second molar at the height established
in the previous step.
The Nose
AnatomyThe Nose
The nose is the superior part of the respiratory tract and contains the peripheral organ of smell.
It is divided into right and left nasal cavities by the nasal septum.
The nasal cavity is divided into the olfactory area and the respiratory area.
Autopsy
General Pathology
Autopsy
Autopsy is examination of the dead body to identify the cause of death. This can be for forensic or clinical purposes.
Chronic myelocytic leukaemia
General Pathology
Chronic myelocytic leukaemia
Commoner in adults (except the Juvenile type)
Features:
- Anaemia.
- Massive splenomegaly
- Bleeding tendencies.
- Sternal tenderness.
- Gout and skin manifestations
Blood picture:
- Marked leucocytosis of 50,-1000,000 cu.mm, often more
- Immature cells of the series with 20-50 % myelocytes
- Blasts form upto 5-10% of cells
- Basophils may be increased
- Leuocyte alkaline phosphate is reduced
- Anaemia with reticutosis and nucleated RBC
- Platelets initially high levels may fall later if patient goes into blast crisis.
Bone marrow:
- Hyper cellular marrow.
- Myeloid hyperplasia with more of immature forms, persominatly myelocytes.
Chromosomal finding. Philadelphia (Phi) chromosome is positive adult cases .It is a short chromosome due to deletion of long arm of chromosome 22 (translocated to no.9),
Juvenile type :- This is Ph1 negative has more nodal enlargement and has a worse prognosis, with a greater proneness to infections and haemorrhage
Biologic Width
Conservative DentistryBiologic Width and Drilling Speeds
In restorative dentistry, understanding the concepts of biologic width and
the appropriate drilling speeds is essential for ensuring successful outcomes
and maintaining periodontal health.
1. Biologic Width
Definition
Biologic Width: The biologic width is the area of soft
tissue that exists between the crest of the alveolar bone and the gingival
margin. It is crucial for maintaining periodontal health and stability.
Dimensions: The biologic width is ideally approximately
3 mm wide and consists of:
1 mm of Connective Tissue: This layer provides
structural support and attachment to the tooth.
1 mm of Epithelial Attachment: This layer forms a
seal around the tooth, preventing the ingress of bacteria and other
irritants.
1 mm of Gingival Sulcus: This is the space between
the tooth and the gingiva, which is typically filled with gingival
crevicular fluid.
Importance
Periodontal Health: The integrity of the biologic width
is essential for the health of the periodontal attachment apparatus. If this
zone is compromised, it can lead to periodontal inflammation and other
complications.
Consequences of Violation
Increased Risk of Inflammation: If a restorative
procedure violates the biologic width (e.g., by placing a restoration too
close to the bone), there is a higher likelihood of periodontal
inflammation.
Apical Migration of Attachment: Violation of the
biologic width can cause the attachment apparatus to move apically, leading
to loss of attachment and potential periodontal disease.
2. Recommended Drilling Speeds
Drilling Speeds
Ultra Low Speed: The recommended speed for drilling
channels is between 300-500 rpm.
Low Speed: A speed of 1000 rpm is also considered low
speed for certain procedures.
Heat Generation
Minimal Heat Production: At these low speeds, very
little heat is generated during the drilling process. This is crucial for:
Preventing Thermal Damage: Low heat generation
reduces the risk of thermal damage to the tooth structure and
surrounding tissues.
Avoiding Pulpal Irritation: Excessive heat can lead
to pulpal irritation or necrosis, which can compromise the health of the
tooth.
Cooling Requirements
No Cooling Required: Because of the minimal heat
generated at these speeds, additional cooling with water or air is typically
not required. This simplifies the procedure and reduces the complexity of
the setup.