Optical Devices for Endo Flashcards
Categories of optical devices in endo. (3)
- Basic instruments to facilitate direct and indirect view (hand mirrors, lights)
- Loupes
- Surgical operation microscopes
Characteristics of ‘basic instrument’ mirror. (4)
- smaller size for endo
- front surface coated
- flat surface (concave - not clear)
- consider additional light
3 factors to consider when considering optical effect of loupes
Angle
- large angle = magnification
Distance
- small distance = magnification
Accomodation
- distant object = lens slightly curved
- close object (~25cm) = strong lens curvature
- very close object (<25cm) = limited ability of lens to curve, produces blurred picture
How are optical instruments in dentistry described?
Magnification (2-40x)
2 types of loupes
Galilei
Kepler
What are galilei loupes?
- 2 lens system
- short length
- low weight
- range 1.8-3x (less expensive)
- can be fixed or adjusted
(convex lens at front and concave at back - otherwise image would be flipped)
What are Kepler loupes?
- 2 lens system and prism to rotate picture*
- large field of view
- heavy and only worn in special cases
- 3-6x magnification
- alot of glass with expensive manufacturing
*convex lens at front and at back - need prism between to rotate
How do loupes create good ergonomics?
- good posture (head angle~25 degrees to spine)
- posture enforced by optimum working distance (fixed WD forces dentisy into phsyiologic posture of spine and head)
- loupes designed for a certain WD and this has to be how far away you to see your depth of field
How do loupes create good ergonomics?
- good posture (head angle~25 degrees to spine)
- posture enforced by optimum working distance (fixed WD forces dentisy into phsyiologic posture of spine and head)
- loupes designed for a certain WD (300-550mm) and this has to be how far away you are to your depth of field (area where you will see a sharp image - large for loupes w small mag and smaller for large)
- distance varies between dentist and should be measured
What do loupes do for lens accomodation?
accomodation should be possible with relaxed lens - wide view angle, eye muscles can relax and be worn longer
Best thing about loupes for dentist’s body?
- ergonomics
- accommodation with relaxed lens
T/F More expensive loupes will have larger depth of field
true
What is a field of view?
area you can see
higher the mag, smaller the field - for everyday u want wider
What is depth of field?
amount of depth at end of WD that is in focus
higher mag -> smaller depth of field
Uses for different magnifications of loupes
1.8-2.5x for general work
3-5x for control of prep detail, simple endo
>5x endo and microsurgery
size of pulp chamber is about 2x2mm squared. therefore we need 8-30x
