ali A

bdalla

restoration of badly broken

down teeth

classification of coronal classification of coronal destructiondestruction

location and extend of destruction location and extend of destruction play a role in the selection of play a role in the selection of materials and design of cavitymaterials and design of cavity;;

Destruction can be classified intoDestruction can be classified into::

one cusp missing pin retained ag

two cusps missing

pin retained ag

inlay or onlay

three cusps missingonlay

pins+ crown

pins

I-Pin Retained I-Pin Retained AmalgamAmalgam

DefinitionDefinition of pinsof pins::

pin retained restorationpin retained restoration: : Any restoration requiring the Any restoration requiring the

placement of one or two pins in dentin placement of one or two pins in dentin toto::

provide adequate retention form and or provide adequate retention form and or resistance formresistance form

11--When a large areas of When a large areas of clinical crownclinical crown have been lost because have been lost because of caries or trauma but the pulp still vitalof caries or trauma but the pulp still vital

22--In case of In case of heavily restoredheavily restored tooth premolars and molars and s tooth premolars and molars and subject to fracture of buccal or lingual cuspsubject to fracture of buccal or lingual cusps..

33--Often when a cavity prepared in the Often when a cavity prepared in the lower first mollower first molarsars , the fifth disto-buccal cusps seriously subject to , the fifth disto-buccal cusps seriously subject to traumatic undermining , if this is so , it’s better to retraumatic undermining , if this is so , it’s better to remove this cusp completely and dong the pin retainemove this cusp completely and dong the pin retained restorationd restoration..

indications

44-- When there is a mutilated tooth an When there is a mutilated tooth an d it is considered an strategically im d it is considered an strategically im

portant tooth for a bridge work i.e. a portant tooth for a bridge work i.e. a s an abutment for bridge work , so it’ s an abutment for bridge work , so it’ s better to do a pin retained restorat s better to do a pin retained restorat

ion pin retained amalgam restoratio ion pin retained amalgam restoratio n which become ready for the crown n which become ready for the crown

and the bridge work as a retainer and the bridge work as a retainer

55 - -Following the Following the root canal treatmentroot canal treatment , due to th , due to the tooth or the remaining tooth structure truly in e tooth or the remaining tooth structure truly in need for strengthening after it is being lost it’s need for strengthening after it is being lost it’s vitality and a large amount of tooth structure , vitality and a large amount of tooth structure , sso for some instances the tooth may be get a pro for some instances the tooth may be get a protection by doing pin retained restorationotection by doing pin retained restoration espe especially by using the adhesive restoration that tencially by using the adhesive restoration that tend to increase the fracture resistance of the tootd to increase the fracture resistance of the tooth and the full protection will be gained or produh and the full protection will be gained or produced through preparationced through preparation o f crown or full co o f crown or full co

verage restoration verage restoration..

types of pinstypes of pins

cemented

friction locked

self threaded

1-Cemnted (markly)

pin hole

pin trial

cement

pin adjustment

pin cemented

advantage of this advantage of this techniquetechnique::

11-- because the cemented pin does not because the cemented pin does not produce internal stresses and craze l produce internal stresses and craze l

ines in the dentin it's the pin of choic ines in the dentin it's the pin of choic e for use in restoration of root canal t e for use in restoration of root canal t

reated teeth reated teeth22-- pins can be measured ,cut,bent,tria pins can be measured ,cut,bent,tria

l fitted before cementation l fitted before cementation..33-- They are available in three diamete They are available in three diamete

rs to suit avariety conditions rs to suit avariety conditions..44-- any length of pin can be used and e any length of pin can be used and e

asily to be shaped as L shape or U sha asily to be shaped as L shape or U sha pe and this is usufull in some class Iv pe and this is usufull in some class Iv

cavities when pin retention for comp cavities when pin retention for comp osite resins is needed osite resins is needed..

Disadvantages of markely Disadvantages of markely techniquetechnique

11--retention of pins is not as good as other method retention of pins is not as good as other method tetechniquechnique or or

22--length and direction of pins cannot be changed aftlength and direction of pins cannot be changed after cement has seter cement has set..

33--the method is more complicated than other 2 meththe method is more complicated than other 2 methods in that more instruments and materials are needods in that more instruments and materials are neededed..

because zinc phosphate cement are irritant to the debecause zinc phosphate cement are irritant to the dentino pulpal organ a cavity varnish might be used bentino pulpal organ a cavity varnish might be used before cementation into holesfore cementation into holes..

22 - -Unitek system or Unitek system or friction lock pinsfriction lock pins

pins are supplied in deffrent three lengths (pins are supplied in deffrent three lengths (9.5, 7.9, 4.5 mm)with 0.55 mm in diameter9.5, 7.9, 4.5 mm)with 0.55 mm in diameter..

the diameter of pinhole is (0.025 -0.03 mm)smallthe diameter of pinhole is (0.025 -0.03 mm)smaller than that of piner than that of pin..

the depth of pinhole should be 2-4 mm deepthe depth of pinhole should be 2-4 mm deep pinhole are made in dentin with special drill and pinhole are made in dentin with special drill and

placed by means of pin seeter which can be eithplaced by means of pin seeter which can be either straight or bayonet shapeder straight or bayonet shaped..

pins are tapped into holes retained by resiliency pins are tapped into holes retained by resiliency of dentin and are 2-3 times are retentive than ceof dentin and are 2-3 times are retentive than cemented pinsmented pins..

stresses stresses are created in the dentin when are created in the dentin when pin is tapped to place and may result in pin is tapped to place and may result in

lateral cracks prependicular to the axis lateral cracks prependicular to the axis of the pins of the pins..

pulpal stresses is maximal when lateral pulpal stresses is maximal when lateral - surface of friction locked pin is adjacen - surface of friction locked pin is adjacen

t to the pulp t to the pulp.. microleakage microleakage occur to a greater degree occur to a greater degree

around friction locked pins than aroun around friction locked pins than aroun - d thread mate system - d thread mate system..

cavity varnish cavity varnish a pplied to pinhole does a pplied to pinhole does not reduce not reduce t he retentive ability of the fric t he retentive ability of the fric- tion locked pin- tion locked pin..

advantages of unitek methodadvantages of unitek method

instruments less expensive than those instruments less expensive than those needed for thread mate system needed for thread mate system..

no nessesary to varnish the holes befor no nessesary to varnish the holes befor e fixing pins due to no need for cement e fixing pins due to no need for cement

ing medium ing medium..give more retention force or means give more retention force or means

than cemented type pinsthan cemented type pins

disadvantages of unitek methoddisadvantages of unitek method

for any reason when the access technique is not goofor any reason when the access technique is not good and poor the techniaue become very difficult to acd and poor the techniaue become very difficult to accomplishedcomplished..

the problems onvolved in using the tap or wedged pithe problems onvolved in using the tap or wedged pins that straight wires or pins being usedns that straight wires or pins being used..

they cannot easily removed if the case necessary aftthey cannot easily removed if the case necessary after they are seated in the toother they are seated in the tooth..

the pins cannot be bent after fixing in the tooth so rethe pins cannot be bent after fixing in the tooth so result in fracture of the portion of the tooth so pin mussult in fracture of the portion of the tooth so pin must not be bent because of the losing the tootht not be bent because of the losing the tooth..

sometimes in careless malleting and handling conditsometimes in careless malleting and handling conditions enamel fracture occurions enamel fracture occur..

33--Thread mate Thread mate systemsystem

thread mate systemthread mate system thread mate systemthread mate system

-00380diameter of prepared pinhole is( . -00380diameter of prepared pinhole is( . .1 ) ,m m smaller than that of pin there is a .1 ) ,m m smaller than that of pin there is a

mmmmmm mmmm mmmmm mm mmm mmmmmm mmmmm mmmm mmmmmm mmmm mmmmm mm mmm mmmmmm mmmmm mmmm mmm mmmmmmmmm mmm mmmmmmmm mm mmm mmmm mmmmmm mmmmmmmmm mmm mmmmmmmm mm mmm mmmm mmm

i de t he hol es when t he access t o cavi t y i s i de t he hol es when t he access t o cavi t y i smmmmmmmm

- but when is not,using contra angle at 200 500r. - but when is not,using contra angle at 200 500r. mmmm mmmm mmmmm mmmm mmmmmm mm mmmmmmm mm. mmmm mmmm mmmmm mmmm mmmmmm mm mmmmmmm mm.

e dept h t o whi ch t he pi n go t hr ough t o bot t e dept h t o whi ch t he pi n go t hr ough t o bot tmm mm mmmmmm mm mmmm..

mmm mmm mm mmmmmmmm mm mmm mmmmmmm mmmmmmmmmm mmm mm mmmmmmmm mm mmm mmmmmmm mmmmmmmm mmm mmmmmmmmm mmmmmm mm mmm mmmmmmmmm mmm mmmmmmmmm mmmmmm mm mmm mmmmmmmm..

it's it's 55 - 6- 6 times more retentive than c times more retentive than c - emented pin and 2 3 times grater than t - emented pin and 2 3 times grater than t

mm mmmmmmmm mmmm mmmmmm mmmmmmmm mmmm mmmm..mmmmmmm mmm mmmmmm mmmmmmmmm mmm mm mmmmmmmmmmmm mmm mmmmmm mmmmmmmmm mmm mm mmmmm

ed in the dentin when self threading pin ed in the dentin when self threading pinm mmm mmmmmmmmm mmm mmmmmmmm . .

insertion of these pins produce more cra insertion of these pins produce more crammmm mm mmm mmmmmm mmmm mmmmm mm m mmmmmmmmm mm mmm mmmmmm mmmm mmmmm mm m mmmmm..

advantage of TMS advantage of TMS methodmethod: :

the technique can be cosidered the easiest the technique can be cosidered the easiest of three types of pin retained restorationsof three types of pin retained restorations..

the retention and resistence for the restoratthe retention and resistence for the restoration considered the greatest one than the otion considered the greatest one than the othershers..

pins can be bent after insertion and fixed in pins can be bent after insertion and fixed in sound dentin without fracture of the tooth ssound dentin without fracture of the tooth structuretructure..

no need for the intermediary cement materino need for the intermediary cement material for fixation of pins so no further irritation al for fixation of pins so no further irritation couldcould be result be result..

disadvantages of TMS disadvantages of TMS methodmethod::

this system is considered an expensiv this system is considered an expensiv e technique with it's tools and materi e technique with it's tools and materialsals..

it's advise not to use in cases of old a it's advise not to use in cases of old a ges patients as the dentis loss it's ela ges patients as the dentis loss it's ela

sticity and in cases of endodontically sticity and in cases of endodontically treated teeth as the tooth liable for fr treated teeth as the tooth liable for fr acture during insertion of pins acture during insertion of pins..

Pin Pin techniquetechnique

pin sizepin sizepin Nopin No..locationlocation

designdesigndrilling pinholedrilling pinholepin placementpin placement

TMS can be obtained in 4 TMS can be obtained in 4 different different diametersdiameters::

))regular, minim, minkin and and regular, minim, minkin and and minutaminuta((

and in several different designsand in several different designs::))standard, 2 in one, self shearing standard, 2 in one, self shearing

typetype

size

diametdiameterer

PinPin HoleHolerregular egular .78 .68m .78 .68m

mmminim .61 .53mmminim .61 .53mmminikinminikin . .48 48 . .38mm38mmminuta .38 .34mmminuta .38 .34mm

two factors affect selection of size:

amount of dentin available

amount of retention

for posterior teeth=minikin and minim

for anterior teeth=minim

numbenumberr

several factors affect Noseveral factors affect No..11--amount of missing tooth structureamount of missing tooth structure

22--amount of dentin availableamount of dentin available33--amount of retention requiredamount of retention required

size of pinsize of pin

ONE PIN FOR MISSING AXIAL LA SHOULD BE USED

LOCATIONLOCATION

no closer than .5-1mm to DEJno closer than .5-1mm to DEJ or no closer than 1-1.5 mm to or no closer than 1-1.5 mm to

external tooth surfaceexternal tooth surfacenot close to vertical wallnot close to vertical wallprepared on flat surfaceprepared on flat surfaceinterpin distance =3mminterpin distance =3mm

pinhole drillingِِِِِِِِِِِِِِِِِِِِِِِِِ

kodex drillhigh speed tool steel

al shank

start point

Round bur

hand piece at very low speed 300-500 apply pressure and prepare pinhole in one movement

drill

Pin hole

self shearing

standard

2 in 1

design

wrench.

chucks

placement

pin placement

pin

Bending…

factors affecting the retention of factors affecting the retention of the pin in dentin and amalgamthe pin in dentin and amalgam

11--types of pinstypes of pins:: self threading pins offer three time self threading pins offer three time

s more retention than friction lock s more retention than friction lockaa nd cemented ones nd cemented ones..

22-- numbers of pins numbers of pins:: within limits increasing the number of pin within limits increasing the number of pin

s increase retention in s increase retention in dentin and in amalg dentin and in amalgamam..

but at the same time dentin crazing and fra but at the same time dentin crazing and fra cture potential increase cture potential increase

the amount of dentin available between pi the amount of dentin available between pi ns become less and ns become less and amalgam resistence al amalgam resistence al so decrease so decrease..

so when determining the number of pins to so when determining the number of pins to be used u must take into be used u must take into cosideration seve cosideration seve ral factors and know the problems which m ral factors and know the problems which m

ight be ight be

33--size of pinssize of pins:: within limits as the diameter of pi within limits as the diameter of pi

nsns increase increase retention in dentin retention in dentin and malgam increase and malgam increase. . i ncrease i ncrease

diameter of pin increase the forc diameter of pin increase the forc e which is required e which is required toto d isplace o d isplace o r fracture or debonding pin from r fracture or debonding pin fromtoothtooth..

the danger of pulpal penetration the danger of pulpal penetration and external perforation increase and external perforation increase

as number, depth, diameter of pi as number, depth, diameter of pi ns increase ns increase..

A large no. and excessive length of pins can severely compromise condensation of amalgam and its adaptation to the pins.

44--the depth of pinthe depth of pin:: it's better to select and choose the syst it's better to select and choose the syst

em of pin that give us a em of pin that give us a maximum rete maximum rete ntion with short extension in sound de ntion with short extension in sound de

ntin to avoid perforation to surroundi ntin to avoid perforation to surroundi ng peridontium or pulp chamber ng peridontium or pulp chamber . .

cemented cemented pp in increase its retention by in increase its retention by increasing its depth in dentin but on t increasing its depth in dentin but on t

he other hand self threading pin achie he other hand self threading pin achie ved their maximum retention within 2 ved their maximum retention within 2

mm in dentin mm in dentin....

drilling should be done a drilling should be done a gainst flat surface gainst flat surface. . drillidrilli

ng against a sloping surf ng against a sloping surf ace makes calculation of ace makes calculation of

pinhole depth difficult pinhole depth difficult

RESTORATIVE RESTORATIVE MATERIALS MATERIALS PLACEMENTPLACEMENT

AUTOMATRIX OR CUPPER BAND

HIGH CU

AMALGAM

AMALGAM PIN

II-SLOT RETAINED II-SLOT RETAINED AMAGAM AND AMAGAM AMAGAM AND AMAGAM

PINPIN

Failure of pin Failure of pin retained retained

restorationsrestorations::

11--broken drill and broken pinbroken drill and broken pin

2-loose pin

3-penetration into pulp and external tooth surface

11--broken drill and broken pinbroken drill and broken pin

causes

drill will break if stressed laterally or stop rotating before removal from pin hole

treatment

another location1.5mm from the first one

2-loose pin

pin hole is too large

treatment

removed and use another one

hole is prepared with next large drill and pin

cemented

3-penetration into pulp and external

tooth surface

penetration into pulp

treated as exposure

3-penetration external tooth surface

occlusal to gingival attachment

cut of

cut of+ preparation extend gingival

removed and hole restored w amlgam

3-penetration external tooth surface

apical to gingival attachment

surgical exposure, enlarge hole and restored w amalgam

crown lengthening procedures +amalgam

see u next

lecturer