Complex direct restorations Flashcards by Mushira ali

complex posterior direct restorations

used to replace any missing structure of teeth that have fractured, have extensive caries or have existing restorative material

usually replace on or more missing cusps

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incidence of tooth fracture

molars are frequently presented fractures than premolars

buccal cusp of maxillary molars

lingual cusp of mandibular molars

most fractured teeth had been restored on three or more surfaces

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Treatment plan options

Indirect restoration - onlay/crown - teeth with crowns are less likely to recieve extensive treatment (over a 10 yr period) than are teeth with large amalgam restorations - treatment of choice

DIrect restoration - complex direc restoration - less expensive, transitional restoration

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Indications for Complex direct restorations

definitive final restorations - patient financial concerns

transitional restorations - pending final treatment plan, questionable pulpal or periodontal prognosis, management of caries

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Indications for complex amalgam restorations

molars

lack of cervical enamel

high caries risk/poor oral hygiene

financial concerns

no esthetic requirements

no amalgam phobia

patient requires a short appointment

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reduction of weakened cusps

fracture strength increases when cusps are covered (removed or reduced)

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Rules for Cusp removal

if unsupported tooth structure OR caries extension from primary groove to cusp tip (up the cusp incline) is:

1/2 the distance: NO removal is indicated

1/2 to 2/3 the distance: consider cusp removal

over 2/3 the distance: remove the cusp

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Cusp Reduction

Remember amalgam needs 2.0 mm for sufficient bulk - for resistance to fracture

reduce cusps to give enough space - 2.0 mm

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pulp protection

direct pulp cap - small exposure, previously asymptomatic

indirect pulp cap - less than .5 mm remaining dentin thickness

thermal protection - mostly under amalgam restorations

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goal of pulp capping procedures

maintain a healthy pulp

stimulate dentin bridge formation

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conditions necessary for a successful pulp cap

pulp is vital

asymptomatic pre operatively

small exposure

isolated - not contaminated with saliva

no excessive hemorrhage

the restoration is well

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materials for pulp protection

MTA

calcium hydroxide

calcium silicate

glass ionomer

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MTA

mineratl trioxide aggregate - same compounds as Portland cement (calcium oxide, aluminum oxide, silicone dioxide)

“bioactive” and “dentinogenic” - used in direct pulp capping procedures

advantage: reparative dentinogenesis was observed earlier than with calcium hydroxide

cover with GI or RMGI

expensive

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calcium hydroxide

gold standard - direct and indirect pulp capping

placed on the exposure or pink dentin

placed only on axial or pulpal floor

soluble - must not extend to margins, wash out of material will result in open margins

low compressive strength - should be covered with GI or RMGI

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calcium silicate

tricalcium silicate in a hydrophyllic monomer

stimulates hydroxy apatite and secondary dentin bridge formation

direct and indirect pulp cap

light cured

increments of no more than 1.0mm

liner not required over Theracal

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Glass Ionomer/Resin Modified Glass Ionomer

Liner not a pulp therapy material

should not be used directly over the pulp or if the RDT is <.5mm

used over pulp capping materials

auto cure or light cure

can be used in a sandwich technique

fluoride release

Comparison of Pulp Capping Materials

What do we use for pulp therapy

direct or indirect pulp cap

calcium hydroxide directly over the exposure or pink dentin (<.5mm RDT)

theracal can be used instead of calcium hydroxide

axial wall or pulpal floor only

thin layer

atleast 1.0 mm from cavosurface margins

should not compromise retentive features of the preparation GI or RMGI over the calcium hydroxide. GI/RMGI not neessary over Theracal

currently under review at the dental institute

Liners

GI or RMGI should not be placed in contact with the pulp

GI or RMGI - closed sandwich (restorative material is present at all cavosurface margins, open (Gi/RMGI is exposed at cervical margins

sandwich technique is used for composite restorations

GI or RMGI can be used under amalgam restorations as a liner for thermal protection

Final Tooth Preparation

Retentive features

opposing vertical walls

coves and locks

pins

amalgam pins

opposing walls

slightly convergent

What if there are no opposing walls?

try to create proximal boxes which have converging walls

hard stained dentin - no need to remove

Slots, Coves and Locks

Slots & Coves are horizontal

Locks are vertical

Slots remove more tooth structure than pin placement

Slots do not create internal stresses in dentin

slots, coves and locks are placed in dentin, not at the DEJ

330 bur

Pins

Self threading pins come in a variety of sizes (diameters)

slightly larger than the drill

placed w/a slow spped handpiece

self threading and self shearing

placed in dentin - 2.0 mm into dentin, 1.5 - 2.0mm extends out of the dentin into the prep

2.0 mm space for the amalgam occlusal to the pin

one pin per missing line angle

3-5 mm between pins

pin hole/ pin is placed parallel to the external surface of the tooth (to avoid perferation out of the tooth)

Pins Cont'd

**provide retention only - do not strengthen the amalgam** problems: perforation into the pulp or periodontium stresses generated in dentin broken/loose pins 2.0mm amalgam above the pin, 2.0mm pin extending above the floor of the prep, 2.0 mm of pin into dentin, pins are parallel to the external surface of the tooth

Pins Cont'd AGAIN

green areas are the preferred areas for pin and other retentive features white areas are to be avoided bc of furcations, concavities or thin dentin grey areas can have retentive features placed with caution

Amalgam Pins

used when there is insufficient room to place self threading pins can be prepared w/a 330 bur 1. 0mm in diameter 2. 0mm in depth used mostly when there are few or no vertical walls mechanical retention forms (slots, amalgam pins and grooves) are less likely to create stress in dentin, microfractures or penetrate into the pulp than threaded pins

Amalgam bonding

etch enamel and dentin, rinse, leave moist apply multiple coats of primer, dry mix catalyst and base of a **self cure** or **dual care** resin cement or unfilled resin base and catalyst apply to dentin and condense amalgam immediately amalgam mixes with the resin cement

amalgam bonding retention

no diff between the performance of pin retained amalgam and bonded amalgam restorations amalgam bonding agents were equal to four pins or four amalgam pins

amalgam bonding resistance

amalgam bonding has little effect on frature resistance of teeth no evidence to either clain or refute a differnce in survival between bonded and non bonded amalgam restorations

Remember

Amalgam must be 2mm in thickness to resist fracture final amalgam must have 2mm of thickness over cusps all condensation must be completed before the amalgam beings to set - can not add amalgam to set amalgam

Modification Request

What - this is what you want to do - this is a VERB - extend, deepen, prepare where - use proper terminology why - usually to remove caries or unsupported tooth structure how much - estimate

placement of pulp protection

mix a small amt of calcium hydroxide (Dycal) apply the Dycal w/ the small ball burnisher to the area showing the pulp exposure or pink dentin placed in the deepest area of the pulpal or axial wall only clean any excess from the margins, floor or axial wall w/ a spoon excavator so the calcium hydroxide is only in the area that would be pink dentin or the pulp exposure **never at cavosurface, should not remain on the axio pulpal line angle, not used on the entire pulpal floor, must be covered w/ GI or RMGI**

Ketac Bond

shake the bottle to fluff up the powder use one level scoop of powder dispense the liquid hold the bottle vertically dispense one drop one scoop of powder to one drop of liquid mix w/ a spatula 10 sec working time 2 min set in 4 min

Vitrebond Plus (this or ketac over calcium hydroxide - dycal)

Remove the cap dispense the two pastes - one click of the dispenser clean off the dispenser tips and recap mix w/ a spatula - 10 sec working time is 2 min 30 sec the cement can be applied to the area of the prep w/ a small ball burnisher 20 sec cure