revision

Critical pH of enamel?

~5.5

Critical pH of dentine?

~6.2

What is stress and strain?

Formula of young’s modulus?

Stress/strain

Toughness

Radiation absorbed dose

Radiation-absorbed dose, equivalent dose, effective dose, radiation weighting factor, tissue weighting factor

ALARA and ALADA

As low as reasonably achievable, as low as diagnostically acceptable

Reduce radiation

Use field-defining cone, use longer cone, shielding (lead aprons, thyroid collars)

Eukaryotes vs prokaryotes?

Eukaryotes: genetic material within nucleus, have membrane enclosed organelles

Gram -ve vs +ve

Gram -ve: 2 lipid bilayer membranes, inner membrane and outer membrane(with lipopolysaccharide)

+ve: only one cytoplasmic membrane: inner membrane

Fancy terms

Im supragingival plaque, how many % of bacteria and solids respectively?

70-80% bacteria, 20-30% solids.

Subgingival plaque has higher relative portion of bacteria

Specific plaque hypothesis, non-specific plaque hypothesis, and ecological plaque hypothesis

Two components of biofilm?

Biofilm = cells+matrix

Does a single bacterial species cause caries or PD?

No. It results from disruption of normal biofilm homeostasis, causing ecological imbalance.

Significance of CEJ?

1. To show whether there is periodontitis

2. Act as a landmark to measure gingival recession

Memorise

Definition of tooth eruption and emergence?

Eruption: the axial movement of a tooth from its nonfunctional position in the bone to functional occlusion.

Emergence: the moment when any part of the cusp or crown appears through the gingiva.

Primary mechanism for post-emergent eruptive movement?

Collagen fibres. As collagen matures, it crosslinks and shortens, this provides a potential propulsive mechanism for eruption.

In tooth eruption, what does the coronal part and basal part control respectively?

Coronal: osteoclastogenesis

Basal: osteogenesis

What factors affect pre-emergent eruption and post-emergent eruption respectively?

Pre: resorption rate

Post: light, long- duration forces and blood floq

Def of amalgam?

A mixture of metals, consisting of liquid mercury and a powdered alloy composed of sikver, tin, copper etc.

Trituration meaning and steps?

The process of mixing the amalgam alloy particles with mercury.

1. Remove oxide layer on surface of metal alloy

2. Wetting by Hg

3. Amalgamation

Main advantages and disadvantages of amalgam?

Advantages: durable, good long-term clinical performance, economical(cost effective)

Disadvantages: some destruction pf sound tooth tissue, poor esthetic qualities, local allergic potential, concern about possible mercury toxicity

Ionizing radiation?

Radiation with ENOUGH ENERGY so that during interaction with atom, it can remove tighly bound electrons from orbit of atom, causing atom to be ionized.

Relationship between linear attenuation coefficient and atomic number?

X-ray attenuation is directy proportional to the cube of atomic number.

What metal should be used as dental mirror?

Rhodium(Rh)

Bones that make up nasal septum?

Ethmoid, vomer

Position of condylar process, mandibular notch, and coronoid process?

Borders of anterior and posterior triangle of neck?

Anterior: SCM, midline of neck, mandible

Posterior: SCM, clavicle, trapezius

Contents of carotid sheath?

Carotid arteries, internal jugular vein, cranial nerves 9-12

How does cranial nerve 1-12 exit skull?

.

Location of parotid papilla?

Adjacent to 2nd upper molar