2. INTRODUCTION
Most of the teeth can be restored with amalgam and
composite but if large crown portion lost due to caries
or some other reasons, the remaining tooth structure
is decrease and difficult to obtained resistance and
retention form so prepare dentine lock and slot but
when these retention features are insufficient to
provide desired retention then pin supported
restorations are used.
3. TRETMENT OF BADLY BROKEN TOOTH
First-Evaluate biologically and mechanically
Status of pulp and periodontium should be evaluated.
Involvement of pulp or not
Restorative design planning
if pulp is not involve-pin,inlay,onlay
Pulp involvement- pulpotomy ,pulpectomy, pin,full
coverage-
Tooth anterior or posterior
4. HISTORY
In 1958, Dr. Miles Markley introduced a practical
instrumentation for the use of a stainless steel
cemented pin that resulted in the extensive use of
cemented pins in dentistry
5. DEFINITION
Defined as any restoration which requires the
placement of one or more pins in dentin to provide to
adequate resistance and retention form to the
restoration.
It has a greater retention than those using
boxes or bonding system.
6. INDICATIONS
Badly broken down or mutilated teeth.
Questionable prognosis-Controlled restoration in
tooth with questionable pulp or periodontal
prognosis
As a foundation under fixed restoration(core)
Economics
Age and health of the patient
7. CONTRAINDICATIONS
Occlusal problems
Esthetics-Rarelly used in anterior teeth(Bonding
Technique).
Access difficulties-In class V horizontal groove in the
gingival & occlusal aspect etc.
8. ADVANTAGES
Conservation of tooth structure
save time compared with cast restoration.
Greater resistance and retention form
Economics
9. DISADVANTAGES
Dentinal micro fractures or crazing
Lowered fractured resistance
Strength of amalgam restoration is reduced
Micro leakage around pin
Perforations of pulp or ext. tooth structure.
Difficulty to achieve proper contours
12. FRICTION LOCKED PINS
Developed by Dr. Goldstein in
1966
Made of stainless steel
More retentive than cemented
pins
Used in vital teeth with good
access and ease of tapping/locked
the pins
Cause craze lines or cracks
Retain by resilience of dentin
13. SELF THREADED PINS
Developed by Dr. Going in
1966
Most popular type among all,
the different types and most
extensively used pin.
Made of stainless steel or gold
plated titanium pins
Provide maximum retention
among all types of pins
Cause craze lines
Used in vital teeth
14. CEMENTED PINS FRICTION LOCKED PINS SELF THREADED PINS
Stainless steel with
threads or serrations
Stainless steel with
threads
Stainless
steel/Titanium with
gold plating
Pin channel [0.020”
to 0.32”] larger than
pin size [0.018” to
0.30”]
Pin channel is 0.001”
smaller than pin size
Pin channel is 0.015”
to 0.004” smaller
than pin size
Luted with standard
luting agents
Taped into place with
mallet
Placed by hand
wrench or contra
angle hand piece
Ease of placement Pin placement is
difficult
Pin placement is easy
15. CEMENTED PINS FRICTION LOCKED PINS SELF THREADED PINS
Less internal stresses Increased internal
stress
Increased internal
stresses
Least retentive 2-3 times more
retentive than
cemented pins
5-6 times more
retentive than
friction locked pins
18. REGULAR MINIM MINIKIN MINUTA
•Largest
diameter pins
•Causes
maximal stress
•Causes
maximum
dentinal crazing
•Rarely used
•Next smaller
diameter pins
•Lesser stress are
created
•Lesser dentinal
crazing
•Good retention
•Diameter is
lesser than
minim pins
•Very less risk of
dentinal crazing
•Good retention
•MINIM AND
MINIKIN ARE
COMMONLY
USED SIZES OF
TMS SYSTEM
•SMALLEST
SIZE of pins
•They are too
small to
provide
adequate
retention
•Not widely
used
20. Standard
design
•7mm long
•They have flattened heads to fit into the hand wrench or
handpiece chuck
•After placement the pin is reversed 1/4th turn to reduce
stresses on dentin
•Pin height can be adjusted appropriately
Self
shearing
design
•Available in varying lengths
•They have flattened heads to fit into the hand wrench or handpiece
chuck
•During pin placement when the pin reaches the bottom of the pin
hole, the head automatically shears off, leaving a portion projecting
from dentin
Two in one
design
•It consists of 2 pins connected by means of a joint which serves as a
shear line for peripheral pin
•Total length is 9mm and 2 pins are about 4mm each
•They have flattened heads to fit into the hand wrench or handpiece
chuck
•The handpiece need not be reloaded during insertion of more than
1 pin
21. Link series
design
•They have a plastic sleeve that fits into the latch type contra
angle handpiece or a special plastic hand wrench
•Self shearing
•Pin engages the dentin and the plastic sleeve can be
discarded
•Can align well into pin channels
Link plus
design
•Similar to link series design
•Self shearing
•Available as single or 2 in 1 pins
•The major difference in this pin design is that pins have sharper
threads and a tapered tip to decrease dentinal stresses while
seating
22. ADVANTAGES OF TMS PINS
Versatile design
Wide range of pin sizes
Color coding allows ease
of use
Gold plating eliminates
corrosion
Good retention
23. FACTORS AFFECTING THE RETENTION OF
THE PIN IN DENTIN AND AMALGAM
Orientation, number and diameter
-Non-parallel pin - ↑ retention
-Bending of pin – not desirable
Interfere with condensation of amalgam
Weaker pin, fractured dentin
↑ no. of pin - ↑ retention
↑ crazing & fracture
↓ amount of dentin available
↓ amalgam strength
26. MECHANICAL ASPECTS
A] STRESSING CAPABILITIES OF PINS
B] RETENTION OF PINS IN DENTIN
C] MICROCRACKING AND CRAZING
27. MECHANICAL ASPECTS
[PINS AND TOOTH STRUCTURE]
A] Stressing capabilities of pins
Type of pins
Diameter of pins
Pin depth and dentinal
engagement
Bulk of dentin
Type of dentin
28. Shape of pin channels
Loose pins
Irregularly shaped
dentinal end of pins
Ratio of dentinal
engagement : pin
protrusion [ideal 2:1]
Number of pins in one
tooth
29. Drill – its use and function
Stresses induced during shortening pins
Retentive features
Inserting pins in stress concentration area of tooth
30. B] RETENTION OF PINS IN
DENTIN
Type of pin
Pin depth and dentinal
engagement
Pin channel
circumferential shape
relative to that of pin
Inter pin distance
31. Type of cement
Ratio of dentinal engagement : pin protrusion [ideal
2:1]
Type of involved dentin
Surface roughness of the pins
Mode of shortening of pins after insertion of pins
Bulk of dentin around the pin
32. C] MICROCRACKING AND CRAZING
Type of pin
Proximity of pin to DEJ
Induced stresses in involved dentin
Type of dentin
34. MECHANO ANATOMICAL
ASPECTS FOR PIN PLACEMENT
Anatomical features
Tooth alignment
Cavity extent
Effect of age or relative age on the pulp chamber
39. PIN CHANNEL PREPARATION
Twist drill-By using twist drill latch type or depth
limiting drill at low speed ( 300-500) RPM
No. 1/4 round burs- first make pilote hole with
round bur to localize position of the pin the
complete the hole in one or two thrust(
movement)
Apply intermittent pressure
40. CEMENTED PIN TECHNIQUE
INDICATIONS
Ideal technique
Only technique for endodontically treated tooth
Only technique to be used when avaliable
location of the pin is close to DEJ
41. Ideal technique for a sclerotized / tertiary / calcific
barrier / highly demineralized / dehydrated dentin
For class IV restorations
When there is limited bulk of dentin
42. PROCEDURE
Preparation of pin channel
Checking the surface irregularities of pins
Slow setting phosphate / polycarboxylate introduced
by perio explorer tip or lenticulo spiral at slow speed
Placement of pin using lock in or magnetised tweezer
or hemostat
43. Large amalgam plugger is needed to check the
complete seating of the pin
In case of class IV restorations, bending of the pins is
to be done before cementation of the pin channel
44. THREADED PIN TECHNIQUE
INDICATIONS
Vital teeth
Dentin to engage the pin is either primary or
secondary
Minimum avaliable location is 1.5mm from DEJ
If minimum pins are needed for the restoration
45. PROCEDURE
Preparation of pin channel
Pin is engaged to a driving device and pin is
continuously threaded into the pin channel until it
offer resistance initiated by the pin channel floor
Desired length of the pin can be cut using small bur
and high speed handpiece in the direction of
threading and with light intermittent touches
Surface irregularities are corrected
No bending should be performed
46. FRICTION GRIP PIN TECHNIQUE
INDICATIONS
For vital teeth
When bulk of dentin is present [min 4mm in all 3
dimensions]
Only in the accessible areas
47. PROCEDURE
Pin channel is prepared
Checking the surface irregularities of pins
Put a colored mark on the pin to indicate the
exact depth of the pin channel using a measuring
probe
Pin is held in its place at the entrance of the
cavity
Concave headed seater is placed on the pin
48. With the hammer light strokes are given until that
colored mark
Remove all the holding devices
Check for cracks, chipped pieces or grossed fractures
49. CAVITY PREPARATION
Remove all carious and weakened tooth structure
Initial cavity is prepared with dovetails, boxes,
grooves etc
Facial and lingual walls are kept parallel wherever
possible
Margins are placed supra-gingivally
50. Areas to receive pins should be flat and perpendicular
to long axis of the tooth.
There must be enough dentin for pin placement
Weakened cusps should be reduced and occlusal
contour should follow the normal contour of the
unreduced tooth
PULP PROTECTION
51. CLASS II DESIGN
Pins should be put in apically deepest and most
peripheral parts of the cavity
Pin should not be placed below the cusp
Decreasing the stress concentration on the pin
Use of minimum number of pins with less diameter
Placement of the pin should be such that theres
enough restorative material around it
52.
53. CLASS V DESIGN
Pins are placed axially parallel
to the adjacent proximal surface
Pin protrusion should be
minimal
Deep retentive grooves are
placed
Pins should be placed midway
in the preparation but as close
to gingival wall as possible
58. EFFECT OF PINS ON PULP
Generally it responds positively and accepts its
presence without any adverse effects
Histologic evaluation reveals inflammatory response,
necrotic tissue encapsulation, fibrous tissue
regeneration and formation of pre dentin by
odontoblasts
Inflammatory reactions have been observed under all
kinds of pins
59. CONCLUSION
The prognosis of the involved tooth and its role in
overall treatment plan helps to decide the restoration
to be placed
If amalgam is selected as the restorative material to be
placed, pins placed in dentin improve the retention of
the restoration
Pins have been extensively used in the past to restore
such badly broken tooth