12 - Pins

Question 1

indications for retention

Answer 1

gross loss of tooth structure, widely extended prep, loss of cusps, large lesion/questionable prognosis, bases for C&B procedures

Question 2

what are the types of pin systems

Answer 2

1. cemented
2. friction (not used anymore)
3. self-threading (use in lab and clinic)

Question 3

what pin:

Diameter of pin is less than that of the bur used to prepare the
channel
Retention of pins is proportional to the length of pin engaging the
dentin and strength of the cement

Answer 3

cemented pin

Question 4

advantages and disadvantages of cemented pins

Answer 4

advantage: least trauma
disadvantage: requires a cementing medium, least retentive

Question 5

retention for self-threading pins

Answer 5

rely on viscoelasataic property of dentin and the mechanical grasp of threads in dentin. pin hole is narrower than diameter of pin

Question 6

advantage and disdvantage of self-threading pins

Answer 6

advantage: best retention of 3 systems, no cementing medium

disadvantange: potential for creation of internal stress that could crack tooth, especially true since pin size increases due to different in channel diameter and pin diameter

Question 7

are pins measured in mm or inches

Answer 7

diameter measured in inches

Question 8

what pin goes 2 mm into dentin and has 2 mm above the dentin

Answer 8

minim

Question 9

what goes 1.5 mm into dentin

Answer 9

minikin pin kit

Question 10

what goes 1.3 mm into dentin

Answer 10

minuta pin kit

Question 11

retention increases as pin ___ increases

Answer 11

diameter

Question 12

based on retentive demands, should you use the smaller or largest pin diameter possible

Answer 12

largest

Question 13

based on tooth fracture potential, should you use smaller or largest pin possible

Answer 13

smallest

Question 14

there is a significant increase in retention when pin is how many mm in dentin?

Answer 14

increases fromr 0-2 mm. there is not increase in retention if you make it longer than 2 mm

Question 15

problems with smaller threaded pins

Answer 15

pink breakage or dislodgement

Question 16

problems with larger threaded pins

Answer 16

cause dentin or restoration to fracture

Question 17

thre parts to pink kit

Answer 17

pin, twist drill, means of insertion

Question 18

what system used in clinic and lab

Answer 18

minim

Question 19

what system is closest size to universal application (Anterior and posterior teeth) and can be easily adjusted, both in terms of length and angulation

Answer 19

minim system

Question 20

Answer 20

A= pin #1
B= shear point
C= pin #2
D= self limiting shoulder

Question 21

what to keep in mind when using twist drill

Answer 21

1. keep sharp (15-20 placements, max)
2. run twist drill at correct speed (slowspeed 3000-3500 rpm)
3. maintain good bracing of handpiece
4. do not repeatedly withdraw drill during channel prep

Question 22

what are the two areas of cavity preparation

Answer 22

area of pin placement
rest of the preparation (all caries removed and examin depth and place necessary bases and liners)

Question 23

is it okay to rely solely on pin retention

Answer 23

no

Question 24

create a flat surface or ledge that extends greater than ___ inside DEJ for pin placement

Answer 24

1mm

Question 25

factors to consider during pin placement

Answer 25

depth of channel, length of pin, location and orientation of channel, crazing of tooth structure, number of pins

Question 26

channel should be placed how many mm inside DEJ

Answer 26

1 mm

Question 27

is it more difficult to fully seat larger pins

Answer 27

yes

Question 28

in regular and minim system __mm of pin should be embedded within dentin and __mm exposed above to be embedded in restorative material

Answer 28

2,2

Question 29

how much SA needed over pin for strength

Answer 29

2 mm

Question 30

T/F: presence of pins INCREASES compressive strength of SA

Answer 30

false - decreases

Question 31

when cutting pins, what must dentist, assistant and pt have

Answer 31

eye protection

Question 32

do you make pilot hole for channels

Answer 32

yes with 1/2 round bur in high speed

Question 33

hold twist drill parallel to the what?

Answer 33

external tooth surface to get proper alignment

Question 34

what are the preferred locations for maxillary and mandibular pins

Answer 34

Question 35

considerations for pin placement in molars

Answer 35

1. avoid placing pins in mandibular molar bifurcation 2. avoid placing in maxillary molar trifurcation areas 3. be careful when angulation determination when using secondary site

Question 36

what are frequent secondary sites that are difficult for pin placement

Answer 36

mid-lingual ofmaxillary molars and mid-distal of mandibular moalrs use the roots of these teeth as a guide to orient pin channel preparation may cause channel to be mis-angled and penetrate the pulp

Question 37

pin placement in premolars

Answer 37

- avoid mid-mesial surface of maxillary premolars - avoid mid distal surface of maxilary premolars - not a problem with mandibular premolars

Question 38

how many pins

Answer 38

usually 1 pin for each lost cusp

Question 39

what is the minimum distance between the pins

Answer 39

3-5 mm apart to minimize tooth fracture and condense resotrative material around pin

Question 40

do pins increase or decrese resistance form

Answer 40

decrease

Question 41

was there a relationship demonstrated between rotational speed during channel preparation and complication incidence or type

Answer 41

NO

Question 42

does hand wrenching or using hand piece cause more complications when placing pins

Answer 42

hand piece so hand wrench!

Question 43

common errors of pin placement

Answer 43

1. pulpal penetrations 2. eternal perforation 3. enlarged pin channel 4. twist drill will not cut

Question 44

radiographic information can and cannot determine what when it comes to pin placement

Answer 44

can establish external perforation difficult to determine pulpal exposure

Question 45

what to do if you have an enlarged pin channel

Answer 45

1. redrill deeper channel at same site and seat a new pin 2. cement existing pin into oversize channel using glass ionomer cement 3. new channel 3-5 mm away

Question 46

does the pin bender place the fulcrum within the pin or the tooth?

Answer 46

within the pin, not the tooth