Copy of Amalgam - Cavity preparation summary PDF

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Cavity preparation summary...

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AMALGAM! Steps*of*Cavity* Preparation 1. Exploration!of! Carious!Lesion!

Initial!Tooth!Preparation!Stages

2. Outline!form!and! initial!depth!

3. Primary! resistance!and!

Class*I

Class*II

Class*V

Class*VI

Using!a!round!ended!fissure!bur,! or!a!pear!shaped!bur!the!lesion! is!accessed.!The!most!deepest! and!caries!part!is!the!site!of! entry,!and!the!long!axis!of!the! bur!is!parallel!to!the!axis!of!the! tooth Open!the!fissure!system,!where! the!width!of!the!cavity!is!onethird!the!inter-cuspal!distance.! The!cavity!should!also!be!1.6mm! or!2mm!away!from!the!marginal! ridges!in!premolars!and!molars! respectively. INITIAL!DEPTH:!1.5-2mm!or! 0.5mm!into!the!DEJ. The!step!of!the!two!surface! preps!is!prepared!by!keeping!the! bur!parallel!to!the!buccal/lingual! surface!at!a!uniform!depth!of! 05.mm!inside!the!DEJ.

Using!a!round!ended!fissure!bur,! or!a!pear!shaped!bur!the!lesion!is! accessed.!The!most!deepest!and! caries!part!is!the!site!of!entry,!and! the!long!axis!of!the!bur!is!parallel! to!the!axis!of!the!tooth.

Using!a!round!ended!fissure!bur,! or!a!pear!shaped!bur!the!lesion!is! accessed.!The!most!deepest!and! caries!part!is!the!site!of!entry.

Using!a!round!ended!fissure!bur,! or!a!pear!shaped!bur!the!lesion! is!accessed.!The!most!deepest! and!caries!part!is!the!site!of! entry.

Using!Turbine!with!air-water! spray,!inverted!cone!bur!(5-8°! occlusal!convergence)!Direction! of!the!bur!is!parallel!to!the!long! axis!of!the!tooth!crown.!Enter!the! pit!nearest!the!involved!proximal! surface.!Bur!position!to!begin! proximal!ditch!cut.!Proximal!ditch! is!extended!gingivally!to!dentine! level!of!gingival!wall!moving!the! bur!vestibulo-oral.! The!cavity!should!also!be!1.6mm! or!2mm!away!from!the!marginal! ridges!in!premolars!and!molars! respectively. The!proximal!box!meets!the! surface!at!90°.!The!axiopulpal! floor!should!follow!the!shape!of! the!DEJ!(0.2mm!into!DEJ). Proper!initial!depth:!1.5!-!0.2mm! into!DEJ

Initial!axial!depth:!0.5mm!inside! the!DEJ!and!total!axial!depth! 1.25mm. The!depth!gingivally!is!shallower! than!that!of!incisally/occlusally.!A! depth!of!0.75-1mm!gingivally!and! 1-1.25mm!incisally/occlusally!is! good.! Position!of!the!bur!should!be! perpendicular!to!the!external! surfaces!of!the!tooth!following!the! contour!of!the!tooth.! Double!convexity.

With!the!bur!perpendicular!to! the!enamel!surface!of!the!cusp!a! cavity!is!prepared.!Depth!of! 1.5mm!is!sufficient!to!provide! bulk!of!material!for!strength.!

Resistance!is!achieved!by!flat! pulpal!floor!with!inner!rounded!

Opposing!walls!should!be!parallel! to!one!another!and!should!

While!preparing!such!a!cavity,!a! box!form!cavity!shapes!should!be!

Retention!of!restoration!is! ensured!by!the!creation!of!small!

retention!form!

Final!Tooth!Preparation!Stages

4. Convenience! Form! 5. Removal!of! decay!and!old! restoration! materials!

6. Pulp!Protection!

angles.!The!floor!should!be! perpendicular!to!the!mastication! forces.!Undermined!enamel! structures!should!be!removed.! Retention!is!achieved!by! preparing!the!walls!parallel!to! each!other!and!should!have!a! slight!occlusal!convergence!(5°8°). For!two!surface!preps!resistance! is!achieved!by!flat!gingival!seats,! gingival!walls!meet!at!90°!and! the!axiopulpal!floor!makes!an! obtuse!angle!with!the!pulpal! floor. Give!adequate!convenience!for! instrumentation,!decay!removal,! and!insertion!of!restoration. Remove!the!decay!with!spoon! excavator!or!with!stainless!steel! burs!(rounded).!Diamond!burs! can!be!used!to!remove!previous! composite!restoration!and! tungsten-carbide!burs!to! remove!previous!amalgam! restoration. For!shallow!preps!no!inner!or! base!is!needed. For!deep!preps!CaOH !can!be! used!and!GIC,!RMGI!and! carboxylate!cement!can!be!used! as!base!liners. For!extra!retentions,!retention! grooves!can!be!placed.!They!are! 2

7. Secondary! resistance!and!

converge!occlusally!for!retention, Pulpal!floor!should!be!flat!and! perpendicular!to!the!long!axis!of! the!tooth!and!all!inner!angles! should!be!rounded!for!resistance. Isthmus!should!be!¼!of!the!intercuspal!distance.!The!isthmus! should!also!be!a!constriction! between!the!occlusal!and! proximal!boxes.

attempt!to!be!made.!However! since!the!axiopulpal!wall!has!to!be! parallel!to!the!surface!and!the! walls!should!flow!the!enamel!rods,! the!cavity!will!not!be!convergence! but!will!be!straight!or!even! divergent.

undercuts!along!the!internal!line! angles.!

Give!adequate!convenience!for! instrumentation,!decay!removal,! and!insertion!of!restoration. Remove!the!decay!with!spoon! excavator!or!with!stainless!steel! burs!(rounded).!Diamond!burs! can!be!used!to!remove!previous! composite!restoration!and! tungsten-carbide!burs!to!remove! previous!amalgam!restoration.

Give!adequate!convenience!for! instrumentation,!decay!removal,! and!insertion!of!restoration. Remove!the!decay!with!spoon! excavator!or!with!stainless!steel! burs!(rounded).!Diamond!burs!can! be!used!to!remove!previous! composite!restoration!and! tungsten-carbide!burs!to!remove! previous!amalgam!restoration.

For!shallow!preps!no!inner!or! base!is!needed. For!deep!preps!CaOH !can!be! used!and!GIC,!RMGI!and! carboxylate!cement!can!be!used! as!base!liners. The!use!of!retention!grooves!in! the!axiogingival!line.!

For!shallow!preps!no!inner!or!base! is!needed. For!deep!preps!CaOH !can!be!used! and!GIC,!RMGI!and!carboxylate! cement!can!be!used!as!base!liners.

Give!adequate!convenience!for! instrumentation,!decay!removal,! and!insertion!of!restoration. Remove!the!decay!with!spoon! excavator!or!with!stainless!steel! burs!(rounded).!Diamond!burs! can!be!used!to!remove!previous! composite!restoration!and! tungsten-carbide!burs!to! remove!previous!amalgam! restoration.! For!shallow!preps!no!inner!or! base!is!needed. For!deep!preps!CaOH !can!be! used!and!GIC,!RMGI!and! carboxylate!cement!can!be!used! as!base!liners. No!secondary!retention!needed.

2

2

Retention!grooves,!one!along!the! incisoaxial!line!angle!and!the!other!

Not!to!remove!dentin! supporting!the!enamel.!

2

retention!form!

placed!at!the!line!angle!between! floor!of!the!cavity!and!its!walls! with!round!burs.

Prevent!the!removal!of!dentin! that!supports!the!proximal! enamel Not!to!prepare!the!locks!entirely! in!the!axial!wall!(risk!of!pulp! exposure)!

along!the!gingivoaxial!line!angle,! have!to!be!placed!to!provide! retention!to!the!divergent!cavity.! The!grooves!have!a!depth!of! 0.25mm.!Alternatively!retention! coves!on!the!four!corners!of!the! cavity!can!be!prepared!(depth!of! 0.25mm).

8. External!walls! finishing!

Resulted!90-100°!cavosurface! angles.

Remove!unsupported!enamel! (less!marginal!leakage)! No!beveling! 90° cavosurface!angle!at!the! margins.!

Resulted!90-100°!cavosurface! angles.

Resulted!90-100°!cavosurface! angles.

9. Cleaning!and! Inspection!

Cleaning!of!preparation!walls,! floors!and!margins!from!enamel! and!dentin!chips! (debris)!resulting!from!tooth! preparation.!After!cleaning,!dry! the!preparation!with!air!or!dry! cotton.!Finally,!the!preparation! should!be!inspected!and! disinfected!(alcohol!free! disinfectant)!before!the! insertion!of!the!restorative! material.

Cleaning!of!preparation!walls,! floors!and!margins!from!enamel! and!dentin!chips!(debris)!resulting! from!tooth!preparation.!After! cleaning,!dry!the!preparation!with! air!or!dry!cotton.!Finally,!the! preparation!should!be!inspected! and!disinfected!(alcohol!free! disinfectant)!before!the!insertion! of!the!restorative!material.

Cleaning!of!preparation!walls,! floors!and!margins!from!enamel! and!dentin!chips!(debris)!resulting! from!tooth!preparation.!After! cleaning,!dry!the!preparation!with! air!or!dry!cotton.!Finally,!the! preparation!should!be!inspected! and!disinfected!(alcohol!free! disinfectant)!before!the!insertion! of!the!restorative!material.

Cleaning!of!preparation!walls,! floors!and!margins!from!enamel! and!dentin!chips! (debris)!resulting!from!tooth! preparation.!After!cleaning,!dry! the!preparation!with!air!or!dry! cotton.!Finally,!the!preparation! should!be!inspected!and! disinfected!(alcohol!free! disinfectant)!before!the! insertion!of!the!restorative! material.

COMPOSITE*–*Conventional!

Initial!Tooth!Preparation!Stages

Steps*of*Cavity* Preparation 1. Exploration! of!Carious! Lesion!

2. Outline! form!and! initial!depth!

Class*I

Class*II

Class*III

Class*IV

Class*V

Class*VI

Using!a!round!ended! fissure!bur,!or!a!pear! shaped!bur!the!lesion! is!accessed.!The!most! deepest!and!caries! part!is!the!site!of! entry,!and!the!long! axis!of!the!bur!is! parallel!to!the!axis!of! the!tooth

Using!a!round!ended! fissure!bur,!or!a!pear! shaped!bur!the!lesion! is!accessed.!The!most! deepest!and!caries! part!is!the!site!of!entry,! and!the!long!axis!of!the! bur!is!parallel!to!the! axis!of!the!tooth

Using!diamond!bur!in! order!to!remove!the! lesions.!This!will!leave! the!surface!area! rougher!and!this!will! increase!the!surface! area!and!the! retention!

Using!a!round!ended! fissure!bur,!or!a!pear! shaped!bur!the!lesion! is!accessed.!The! deepest!and!caries! part!is!the!site!of! entry.!Bur!is! perpendicular!to!the! surface.

Using!a!round!ended! fissure!bur,!or!a!pear! shaped!bur!the!lesion! is!accessed.!The!most! deepest!and!caries! part!is!the!site!of! entry.

The!outline!form! should!be! conservative!as! possible,!where!the! width!of!the!cavity!is! greater!then!1.75mm,! or!ideally!2mm.!The! cavity!should!also!be! 1.6mm!or!2mm!away! from!the!marginal! ridges!in!premolars! and!molars! respectively. INITIAL!DEPTH:! 1.5mm!or!0.2mm!into! the!DEJ. The!step!of!the!two! surface!preps!is! prepared!by!keeping!

The!outline!should!be! conservative!as! possible.!Using!Turbine! with!air-water!spray,! inverted!cone!bur!(5-8°! occlusal!convergence)! Direction!of!the!bur!is! parallel!to!the!long!axis! of!the!tooth!crown.! Enter!the!pit!nearest! the!involved!proximal! surface.!Bur!position!to! begin!proximal!ditch! cut.!Proximal!ditch!is! extended!gingivally!to! dentine!level!of! gingival!wall!moving! the!bur!vestibulo-oral.! The!cavity!should!also!

Using!a!carbide!or! diamond!round!bur! prepare!the!outline! form,!extending!the! external!walls!to! sound!tooth!structure! while!preparing!to!a! limited!depth! (pulpally)!0.75mm.! Prepare!the!external! walls!perpendicular! to!the!root!surface! thus!forming!a!90°! cavosurface!angle.!

To!remove!the! lesions,!we!use!the! diamond!bur,!which! will!leave!a!rougher! surface!area! therefore!increasing! the!surface!area!and! the!retention.!Access! lesion!from!the! lingual!side!of!the! tooth. This!prep!is!indicated! for!restoring!large! proximal!areas,!which! include!the!incisal! surface.! The!outline!form!of! this!cavity!is!very! similar!to!that!of!Class! III,!however!the! outline!is!extended! coronally!to!remove! part!of!the!incisal! edge.!External!walls! are!extended!to!sound! tooth!structure!while! preparing!to!a!limited! depth!(pulpally)! 0.75mm.!

Extend!the!external! walls!to!sound! structure. Limited!depth! pulpally!0.5mm!from! DEJ,!0.75mm!from! cementum. The!outline!is! primarily!determined! by!the!location!and! size!of!the!lesion. All!external!walls!are! perpendicular!to!the! external!tooth! surface.!Thereby! parallel!to!the!enamel! rods. The!prep!is!extended! in!all!directions!until!

With!the!bur! perpendicular!to!the! enamel!surface!of!the! cusp!a!cavity!is! prepared.!Depth!of! 1.5mm!is!sufficient!to! provide!bulk!of! material!for!strength.! However,!in! composite!fillings!the! cavity!here!can!be! shallower,!with!a! smaller!diameter. All!stains!should!be! removed.

the!bur!parallel!to!the! buccal/lingual!surface! at!a!uniform!depth!of! 05.mm!inside!the!DEJ.

3. Primary! resistance! and! retention! form!

Resistance!is! achieved!by!flat! pulpal!floor!with! inner!rounded!angles.! The!floor!should!be! perpendicular!to!the! mastication!forces.! Undermined!enamel! structures!should!be! removed.! Retention!is!achieved! by!preparing!the! walls!parallel!to!each! other!and!should! have!a!slight!occlusal! convergence!(5°-8°). For!two!surface!preps! resistance!is!achieved! by!flat!gingival!seats,! gingival!walls!meet!at!

be!1.6mm!or!2mm! away!from!the! marginal!ridges!in! premolars!and!molars! respectively. The!proximal!box! meets!the!surface!at! 90°.!The!axiopulpal! floor!should!follow!the! shape!of!the!DEJ! (0.2mm!into!DEJ). Proper!initial!depth:! 1.5mm!or!0.2mm!into! DEJ Opposing!walls!should! be!parallel!to!one! another!and!should! converge!occlusally!for! retention, Pulpal!floor!should!be! flat!and!perpendicular! to!the!long!axis!of!the! tooth!and!all!inner! angles!should!be! rounded!for!resistance. Isthmus!should!be!¼!of! the!inter-cuspal! distance.!The!isthmus! does!not!have!to!be! the!constriction! between!the!occlusal! and!proximal!boxes.

external!walls!are! positioned!in!sound! tooth!structure. Double!convexity! should!be!established! on!the!axiopulpal! floor.

The!box-form!design! is!considered!to!be! part!of!the!retention. Can!be!achieved!by! increasing!the!surface! area!of!the! restoration.

Etched!enamel!of!the! external!walls!of!the! preparation!is! considered!to!be!the! primary!retention!of! this!type!of!cavity! prep.!

While!preparing!such! a!cavity,!a!box!form! cavity!shapes!should! be!attempt!to!be! made.!However!since! the!axiopulpal!wall! has!to!be!parallel!to! the!surface!and!the! walls!should!flow!the! enamel!rods,!the! cavity!will!not!be! convergence!but!will! be!straight!or!even! divergent.

Retention!of! restoration!is!ensured! by!the!creation!of! small!undercuts!along! the!internal!line! angles.! Not!to!remove!dentin! supporting!the! enamel.! Flame!shaped! diamond!bur!used!to! roughen!the!prepared! surfaces.

4. Convenienc e!Form!

Final!Tooth!Preparation!Stages

5. Removal!of! decay!and! old! restoration! materials!

6. Pulp! Protection!

90°!and!the! axiopulpal!floor! makes!an!obtuse! angle!with!the!pulpal! floor. Give!adequate! convenience!for! instrumentation,! decay!removal,!and! insertion!of! restoration. Remove!the!decay! with!spoon!excavator! or!with!stainless!steel! burs!(rounded).! Diamond!burs!can!be! used!to!remove! previous!composite! restoration!and! tungsten-carbide!burs! to!remove!previous! amalgam!restoration. For!shallow!preps!no! inner!or!base!is! needed. For!deep!preps!CaOH ! can!be!used!and!GIC,! RMGI!and! carboxylate!cement! can!be!used!as!base! liners. 2

7. Secondary! resistance! and!

For!extra!retentions,! retention!grooves!can! be!placed.!They!are!

Give!adequate! convenience!for! instrumentation,!decay! removal,!and!insertion! of!restoration. Remove!the!decay! with!spoon!excavator! or!with!stainless!steel! burs!(rounded).! Diamond!burs!can!be! used!to!remove! previous!composite! restoration!and! tungsten-carbide!burs! to!remove!previous! amalgam!restoration. For!shallow!preps!no! inner!or!base!is! needed. For!deep!preps!CaOH ! can!be!used!and!GIC,! RMGI!and!carboxylate! cement!can!be!used!as! base!liners. 2

No!secondary! retention!needed.

Give!adequate! convenience!for! instrumentation,! decay!removal,!and! insertion!of! restoration. Remove!the!decay! with!spoon!excavator! or!with!stainless!steel! burs!(rounded).! Diamond!burs!can!be! used!to!remove! previous!composite! restoration!and! tungsten-carbide!burs! to!remove!previous! amalgam!restoration. For!shallow!preps!no! inner!or!base!is! needed. For!deep!preps!CaOH ! can!be!used!and!GIC,! RMGI!and! carboxylate!cement! can!be!used!as!base! liners. 2

Groove!retention! must!be!used!in!root! surface.!Prepare!a!

Give!adequate! convenience!for! instrumentation,! decay!removal,!and! insertion!of! restoration. Remove!the!decay! with!spoon!excavator! or!with!stainless!steel! burs!(rounded).! Diamond!burs!can!be! used!to!remove! previous!composite! restoration!and! tungsten-carbide!burs! to!remove!previous! amalgam!restoration. For!shallow!preps!no! inner!or!base!is! needed. For!deep!preps!CaOH ! can!be!used!and!GIC,! RMGI!and! carboxylate!cement! can!be!used!as!base! liners. If!a!large!amount!of! tooth!structure!I! missing,!groove! 2

Give!adequate! convenience!for! instrumentation,! decay!removal,!and! insertion!of! restoration. Remove!the!decay! with!spoon!excavator! or!with!stainless!steel! burs!(rounded).! Diamond!burs!can!be! used!to!remove! previous!composite! restoration!and! tungsten-carbide!burs! to!remove!previous! amalgam!restoration. For!shallow!preps!no! inner!or!base!is! needed. For!deep!preps!CaOH ! can!be!used!and!GIC,! RMGI!and!carboxylate! cement!can!be!used! as!base!liners.

Give!adequate! convenience!for! instrumentation,! decay!removal,!and! insertion!of! restoration. Remove!the!decay! with!spoon!excavator! or!with!stainless!steel! burs!(rounded).! Diamond!burs!can!be! used!to!remove! previous!composite! restoration!and! tungsten-carbide!burs! to!remove!previous! amalgam!restoration. For!shallow!preps!no! inner!or!base!is! needed. For!deep!preps!CaOH ! can!be!used!and!GIC,! RMGI!and! carboxylate!cement! can!be!used!as!base! liners.

Retention!grooves,! one!along!the! incisoaxial!line!angle!

No!secondary! retention.

2

2

retention! form!

8. External! walls! finishing! 9. Cleaning! and! Inspection!

placed!at!the!line! angle!between!floor! of!the!cavity!and!its! walls!with!round! burs.

continuous!retention! groove!in!the!internal! portion!of!the! external!walls!using!a! little!round!stainless! steel!bur!at!low! speed.!The!grooves! prepared!to!a!depth! of!0.25mm.!

Resulted!90-100°! cavosurface!angles

Resulted!90-100°! cavosurface!angles

Resulted!90-100°! cavosurface!angles

retention!form!may!be! indicated!even!when! the!preparation! periphery!is!entirely!in! enamel.! ! In!addition!to!etched! enamel!margin,! retention!may!be! obtained!by!groove!or! other!shaped! undercut,!dovetail! extentions,!threaded! pins!or!a!combination! of!these Resulted!90-100°! cavosurface!angles

Cleaning!of! preparation!walls,! floors!and!margins! from!enamel!and! dentin!chips! (debris)!resulting!from! tooth!preparation.! After!cleaning,!dry!the! preparation!with!air!or! dry!cotton.!Finally,!the! preparation!should!be! inspected!and! disinfected!(alcohol! free!disinfectant)! before!the!insertion!of! the!restorative! material.

Cleaning!of!preparation! walls,!floors!and! margins!from!enamel! and!dentin!chips! (debris)!resulting!from! tooth!preparation.!After! cleaning,!dry!the! preparation!with!air!or! dry!cotton.!Finally,!the! preparation!should!be! inspected!and! disinfected!(alcohol!free! disinfectant)!before!the! insertion!of!the! restorative!material.

Cleaning!of! preparation!walls,! floors!and!margins! from!enamel!and! dentin!chips! (debris)!resulting!from! tooth!preparation.! After!cleaning,!dry!the! preparation!with!air!or! dry!cotton.!Finally,!the! preparation!should!be! inspected!and! disinfected!(alcohol! free!disinfectant)! before!the!insertion!of! the!restorative! material.

Cleaning!of! preparation!walls,! floors!and!margins! from!enamel!and! dentin!chips! (debris)!resulting!from! tooth!preparation.! After!cleaning,!dry!the! preparation!with!air!or! dry!cotton.!Finally,!the! preparation!should!be! inspected!and! disinfected!(alcohol! free!disinfectant)! before!the!insertion!of! the!restorative! material.

and!the!other!along! the!...