Dental amalgam

Question 1

Functions of Wedges

Answer 1

1. adapt the cervical part of the mb closely to prevent cervical overhangs (which are plaque retentive)
2. retract the gingiva during cav prep
3. for temporary separation of the ts: separation shd be = mb thickness
4. so that the ts will come in contact w/ each other. If there is no wedge, there is a space <0.0015 once the mb is removed (where food and bacteria can go in)

Question 2

what does undercarving do?

Answer 2

1. may raise the bite (with prematurities) w/c may cause discomfort if not relieved
2. poor occ anatomy results

Question 3

functions of matrix bands

Answer 3

1. provide for missing wall
2. provide general contour of the proxl surf of resto
3. places the contact area at the desired level
4. imparts good finish to the resto

Question 4

what is the most commonly used matrix band?

Answer 4

universal matrix or the tofflemire

Question 5

where do you place the the retainer holder of tofflemire?

-what is the advantage of tofflemire?

Answer 5

• buccall to the th you are working on bec there is more space
• can be used even when there are 2 or more walls missing [MODB]

Question 6

retainerless system and often used when you have to fill a large cav prep where 2 or more cusps are missing

*what is the disadvantage?

Answer 6

automatrix

*difficult to contour

Question 7

Tofflemire:

• if gingival flr is ideal/supragingival use:
• if subgingival use:

Answer 7

• use type 1

- type 2

Question 8

the position for a typical interprxl cav prep is approx. 1-2mm above the proposed margl ridge OR
same level as the highest cusp [occlusally], and 1mm below gingv margin [cervically]

Answer 8

when placing the band

Question 9

what is the main purpose of the careful resto of contact areas

Answer 9

to protect gingival tissues

Question 10

long axis shd be parallel w/ the dental arch. its slot shd be towards the gingival bec you will remove it occlusally.
-the slot corresponds to the concave side

Answer 10

mb holder

Question 11

the polished layer of a resto is

Answer 11

‘Beilby layer’

Question 12

what are the advantage of polishing?

Answer 12

1. less susceptible to tarnish and corrosion

2. resto lasts longer

Question 13

polishing done at low speed becoz:

Answer 13

1. danger of elevating temp of resto and then th w/c may cause pulp or resto damage
2. danger of rubber cup flying apart at hi-spd
3. brings Hg to the surface w/c would lead to corros’n of Am and loss of strength

Question 14

What are the order of procedures dental amalgam?

Answer 14

1. Trituration
2. Condensation
3. Pre-carve Burnishing
4. Carving
5. Restore the Occlusion
6. Post-carve burnishing
7. Polishing

Question 15

Trituration mix shd produce:

Answer 15

a smooth, non granular, plastic mass of Am

*not to wet and not too dry

Question 16

low Hg-to-alloy mixing ratio

e. g. 1 pellet: 1 drop from Hg dispenser
- aka ‘no squeeze cloth technique

Answer 16

Eames technique

Question 17

enhances the uniformity and plasticity of the mass; a continuation of tritur’n

Answer 17

mulling

Question 18

special note about condensation

*why

Answer 18

before titration, prepare everything for condensation

*because a delay in condensation leads to decreased plasticity and perhaps greater Hg in the final resto

Question 19

Objectives to Condensation

Answer 19

1. to adapt Am intimately to the prepared walls and margins
2. to compact the Am mass, thereby producing as uniform and void-free a resto as possible
3. to reduce the Hg content to as low a level as possible

Question 20

4 phases of Am:

1. gamma
2. gamma 1
3. gamma 2
4. voids or air pockets

Answer 20

1. Ag and Sn (strongest)
2. Ag and Hg
3. Sn-Hg
4. undesirable bec non uniformity or lack of compactness decreases the strength

Question 21

what needs to be controlled

Answer 21

• saliva
• tongue, lips, cheeks, gingiva
• contacting ts and restos
• debris and water coolant

Question 22

what can be used as salivary control?

Answer 22

1. pharmacologic
   - antisialogogues-drugs that suppress saliva
   - anesthetics-px less sensitive to stimuli and less anxious producing less saliva
2. Fluid and debris evacuating equipments
   - high-volume evacuators
   - saliva ejector
3. Fluid absorbing materials
   - cotton rolls: needs to be changed frequently bec are easily saturated
   - gauze: throat shields
   - absorbant cotton pads and wafers: to retract cheeks and provide absorbancy
4. Rubber dam
   - mildy retracts the gum

Question 23

a rubber guard stretched tightly around a tooth

• absolute dyness for a long time
• mildly retracts gums, lips, cheeks, tongue
• saves a lot of time in long run
• not for asthmatic px if breathing is difficult

Answer 23

rubber dam

Question 24

what to do w/ rubber dam sheet?

Answer 24

punch holes in the rubber dam sheet and slide tooth in while clamping it, w/ help of r.d forcep, the frame keeps r.d. in place

Question 25

what are some Tissue Retraction and protection?

Answer 25

1. mouth mirror 2. rubber dam 3. special types of sal. ejec. and HVE tips 4. gingival tissue management

Question 26

``` gingival tissue management techniques 1. mechanical 2. chemomechanical 3. surgical ```

Answer 26

1. if cervical lesion not deep use r. dam - also can use wedge 2. not only retracts gingiva, but also controls hemorrhage - retraction cords 3. surgical: scalpel blades used to cut off gum tissue, or electrosurgery, to cauterize gums

Question 27

where are retraction cords placed? | and to do what?

Answer 27

- tucked into gingival sulcus | - to obtain minimal lateral displacement of free gingiva and not force apically

Question 28

how to insert retraction cords

Answer 28

use thin, blunt-edged blade or side of explorer or spoon excavator -ideally used w/ anesthesia

Question 29

what do retractions cords have on them?

Answer 29

- astringents (allum, ZnCl, tannic acid) | - vasoconstrictors (epinephrine)

Question 30

what do retraction cords do?

Answer 30

- constricts bld vessels so gum tissue decreases in volume | * but may be contraindicated in pxs w/ hypertension, hyperthyroidism, diabetes

Question 31

method used to achieve adequate control of operative field

Answer 31

``` A. Saliva control B. Tissue Retraction and Protection C. Illumination and Viewing 1.overhead light 2. mouth mirror 3. light attached to handpiece D. Use of air-water spray syringe ```