complex amalgam restoration(final)

8/9/2019 Complex Amalgam Restoration(Final)

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Complex AmalgamRestoration


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Complex Amalgam Restoration

Complex amalgam restorationsinvolve replacement of missing toothstructure because of teeth have beenfractured or involved with caries orexisting restorations. It involvesreplacement of one or more missing

cusps, and often requires bondingtechniques.


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INDICATIONS

Large amounts of tooth structure are missing One or more cusps need capping Increased resistance and retention forms are needed

Pins, slots, grooves and boxlike forms provideresistance form

Used as control restorations in teeth ith pulpal orperiodontal prognosis

Used as control restorations in teeth ith caries Used as definitive restorations Used as build up or foundation


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FACTORS

Resistance and retention forms

Status and prognosis of tooth

Role of the tooth in overalltreatment plan

Occlusion

Esthetics Economics


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Resistance and retention forms

Retention features depend on amount ofremaining tooth structure and the toothbeing restored

!ore tooth structure is lost " moreauxiliar# retention is needed


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Status and prognosis of tooth

Caries activit#, endodontic therap#

Control restoration$ %& Protects pulp from oral cavit# and insults

'& Provides anatomic contour

(& )acilitates control of caries and pla*ue

+& Provides resistance against fracture


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Role of the tooth in overalltreatment plan

x- Choice for tooth is influenced b# itsrole in overall tx- Plan

Remember$ in the clinic do not .ust look

at the tooth but consider its role andfunction


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Occlusion

Interim restorations for teeth thatre*uire occlusal alterations


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Esthetics

!etallic appearance


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Economics

Less expensive and less timeconsuming than cast restoration


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CONTRAINDICATIONS

Patient has significant occlusalproblems

ooth cannot be restored ith directrestoration because ofanatomic/functional considerations

0sthetics


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ADVANTAGES 1Conserves

tooth structure1Appointment time$

one appointment 1Resistance and

retention formsincreased

1Cost

DISADVANTAGES1Pinholes and pinplacement$ 2entinalmicrofractures

1!icroleakage 3fromcavit# varnish& 12ecreased strength 1Resistance form is

harder to achieve 1Penetration into pulp

and perforation intoexternal toothstructure

1Anatom#


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CLINICAL TECHNIQUES

Pin-retained amalgam restratins "any restoration requiring placement of one or more

pins in the dentin for resistance and retention forms Pins are used hen resistance and retention forms

cannot be achieved ith slots/locks/or undercuts Pins have greater retention

Pins for Class I4 restorations rare$ small si5e ofanterior teeth 6oever, can be considered for Class I4 on the distal

surface 3distoincisal corner& of canine hen restoredith amalgam

Alternative to pin$ Lingual dovetail


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Slt-retained amalgam restratins

" retention groove in dentin whose

length is in horizontal plane Prepared ith (( 7 or 8 round bur

!a# be used as an alternative to pin1retained or in con.unction ith pin1retained


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Retention differences beteen pins and slots are not significant

Pin 1Pin is usuall# used in

preparations ith feor no vertical alls

Slt 19lots are usuall#

indicated in shortclinical crons and

cusps that have beenreduced '1( mm foramalgam

1!ore tooth structureis removed

1Less likel# to create

microfractures indentin

1Less likel# toperforate/penetrate


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Amaglam !"ndatins

"an initial restoration of severely

involved tooth; tooth is restored sorestorative material serves in lieu oftooth structure to provide retentionand resistance during final cast

restoration


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TOOTH PREPARATION


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Pin-retained amalgamrestratins

2evelopment of resistance form depth cuts Cusp reduction )inal restoration

If the cusp to be capped is located at correct occlusal heightbefore preparation, depth cuts should be made on existingocclusal surface of cusp to be capped Carbide fissure bur 2epth of cuts should be a minimum of ' mm deep for functional cusps

and %-: mm deep for nonfunctional cusps 3p ;%+& If unreduced cusp is at less than correct height, then cuts ill be less- he goal is to have at least ' mm of amalgam thickness for functional

cusps and %-: mm of amalgam for nonfunctional cusps during finalrestoration-

Rounded internal angles

Opposing vertical alls should converge occlusall# to enhance retentionform


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Remove infected carious dentin CaO6 liner and resin1modified glass ionomer base can

be applied It should not extend closer than % mm to slot or pin

Pin t#pes 9elf threading pin is most commonl# used pin and most

retentive of the three t#pes of pins 3self1threadings,cemented pins, friction locked pins& Cemented pin is the least retentive

Pin hole$ =-==%: to =-==+ in- smaller than diameter of

pin Pin drilled into dentin> ma# generate stress heninserted

See powerpoint for factors affecting retention of pin indentin and amalgam


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Pr#lems and !ail"res ! $in-retained restratins

)ailure can occur ithin the restoration At the interface beteen pin and restorative material ?ithin the pin At the interface beteen pin and dentin

?ithin the dentin Pin ma# break during bending if not careful

Choose an alternate location at least %-: mm remotefrom broken pin to prepare another hole

Removal is difficult Loose pin 3example$ as in self1threading pins

sometimes do not engage in dentin> duringpreparation&

Penetration into pulp and perforation of externaltooth surface


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Slt-retained amalgamrestratins

9lots are usuall# placed on facial/lingual/mesial/distalaspects of preparation

he# ma# be continuous or segmented It depends on amount of missing tooth structure and

here pins are used 9horter slots " more resistance to hori5ontal forces @o- (( 7 bur used to place slot in gingival floor and

@o- %BL bur =-: mm axial of 20 2epth is at least =-: mm Length is at least % mm or more


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Amalgam !"ndatins

ooth preparation depends on t#pe ofretention selectedDpin retention> slotretention or chamber retention3endodontic therap#&


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Pin retentin )or broken don teeth ith fe or no

vertical alls

)or foundations, pinholes are furtherdistancefrom external surface of tooth>this is the main difference beteen useof pins for foundation and use of pins fordefinitive restorations


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Slt retentin Placed in gingival floor of preparation

ith @o- (( 7 bur

Placed farther inside 20 than forconventional amalgam preparations

2epth is usuall# =-:1%-= mm and '-= E

+-= mm long


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C%am#er retentin his is recommended hen$

2imension to pulp chamber is sufficient to

give retention and bulk amalgam 2entin thickness in region of pulp chamber

is enough to provide rigidit# and strength

here is an extension into root canal

space '1+ mm 3hen pulp chamberheight is ' mm or less> an#thing greatergives no advantage&


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he end

complex amalgam restoration(final)

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