CHAPTER 8: CLINICAL TECHNIQUE FOR CLASS I-II RESTORATION

use local anesthesia

provides comfort

reduces salivation

improves bonding conditions

ways to clean the tooth before composite placement

with pumice slurry

avoid flavored, glycerin-based, or fluoride-containing prophy pastes.

why avoid certain prophy pastes before bonding

weaken adhesive bonding

they contaminate the surface

when shade be selected

before drying the tooth

dehydration makes teeth appear lighter

effects of contamination after etching

reduces bond strength

degrades composite properties

why checking occlusion before tooth preparation is vital

to avoid placing occlusal contacts on cavosurface / restoration margins and guide final contact adjustment

goals of class I composite prep

no need to bevel occlusal margins because enamel rods are already exposed

no mechanical retention features required because bonding provides retention

access lesion, remove faulty structure, create convenience form, conserve tooth structure

recommended burs for small / moderate preps

small round or elongated pear-shaped burs (carbide or diamond) with round features

shape of cavosurface margin in conservative preps

flared or obtuse

preferred bur for extensive lesions

elongated pear-shaped bur with round features, parallel to long axis

recommended pulpal floor depth

about 0.2mm inside carious DEJ

1.5–2mm flat depth

minimum remaining tooth structure at marginal ridge

molars — ≈2 mm

premolars — ≥1.5 mm

base used if RDT is 0.5–1.5mm

resin-modified glass ionomer / RMGI

base used if RDT is less than 0.5 mm

Ca(OH)₂ / calcium hydroxide liner + RMGI base

direct pulp capping materials

calcium hydroxide or MTA + cover with RMGI base.

maximum thickness per increment

2mm for conventional composites

the c-factor in class I prep

5:1

high shrinkage stress risk, especially at pulpal wall

sandwich technique

RMGI under composite

this is to:

• bond to dentin

• release fluoride

• reduce shrinkage stress

thickness limit for bulk-fill increments

up to 4mm (varies by manufacturer)

one increment per cusp, shaped against cusp inclines, then cured

main concerns with bulk-fill composites

increased wear

possible poor adaptation

limited long-term evidence

main reason for using incremental layering

to minimize polymerization shrinkage and ensure complete curing

purpose of air-thinning the bonding agent before curing

removes solvents

stronger bond strength

creates a thin uniform layer

allows better light penetration

ensuring complete polymerization

isolation method for class I composite restorations

rubber dam isolation

when to use a matrix band for a class I composite preparation

only if the preparation extends into proximal surfaces, making it a class II

importance of enamel periphery in class II composite restorations

because bonding to enamel is more predictable and stronger than bonding to dentin, especially at the gingival wall.

preoperative wedging

helps separate teeth to re-establish proper proximal contact when restoring with composite

goals of tooth prep in class II direct composites

access the defective structure

create convenience form for restoration

remove caries, faulty restoration, or base materials

bur used to remove carious tissue in small class II composite restorations

small round or elongated pear-shaped diamond burs.

box-only class II preparation design

a proximal box preparation only

when occlusal surfaces are sound

prepared parallel to the tooth’s long axis to remove proximal caries

indication of facial or lingual slot preparation

when proximal lesion access can be gained from facial

lingual direction rather than gingivally through the marginal ridge

margins characteristics in facial / lingual slot preparations

marginal ridge must not be undermined

cavosurface margins are 90 degrees or greater

how moderate-large class II composite preparations differ from small ones

they resemble traditional amalgam preparations

may include an occlusal step and proximal box

significance of DEJ in proximal box preparations

it serves as a guide for the pulpal floor depth and the outline of the proximal box.

recommended burs to prepare the proximal box

#330 or #245 diamond burs

facial / lingual walls preparation in the proximal box

preferably more obtuse

parallel to the long axis of the tooth

at least 90-degree cavosurface margins

why bevels rarely used on proximal box margins in class II composite preparations

because bevels make restoration more difficult and viscous composites are harder to adapt there.

because enamel rods are already exposed and bevels make finishing more difficult without providing significant bonding benefits.

preferred matrix types for class II composite restorations

ultrathin metal matrix bands

precontoured sectional metallic matrices

advantages of sectional matrix systems with bitine rings

they stabilize the matrix

provide tooth separation

simplifying proximal contouring / contact

purpose of the wedge during matrix placement

separate teeth slightly

prevent gingival overhang

hold the matrix in position

purpose of sculpting the marginal ridge during composite insertion

to achieve proper anatomy

minimize the need for excessive finishing

preheating composite material

doing this during placement helps:

• reduces viscosity

• improving adaptation

• reducing microleakage

finishing procedure for class II composite restoration

surgical blade for gingival overhangs

polishing with points, cups, or brushes

use carbide burs / abrasive discs to remove excess and shape anatomy

advantage of holding the matrix in physical contact during curing

it ensures a tight proximal contact by preventing composite displacement before curing

primary retention form for large class II composite restorations

micro-mechanical bonding to enamel and dentin

why secondary retention features necessary in extensive class II composite restorations

the need to better retain the composite

because of decreased tooth structure for bonding

secondary retention features used in extensive class II composite restorations

slots

coves

grooves

a cusp is reduced and capped with composite

done if the cusp is weakened due to dentin loss or

if occlusal outline extends more than two-thirds from a primary groove to a cusp tip

location of grooves, coves, slots for retention

strategically in dentin

to maintain dentinal support and avoid pulpal involvement

challenges present during matrix placement in extensive class II restorations

more missing tooth structure

possible subgingival margins

need for proper burnishing / adaptation

should be done during light curing to ensure proper proximal contact

use a hand instrument to hold the matrix against the adjacent tooth during curing.

why dual-cured composites be light cured after placement

to ensure complete polymerization and optimal properties.

compatibility issues between adhesives & self-cured composites

acidic monomers in simplified adhesives can scavenge activators in self-cure composites, inhibiting polymerization

solution:

• using chemical catalysts mixed with light-cured adhesives to prevent activator scavenging

post-restoration protocol for px with extensive composite restorations

frequent recall visits due to the potentially limited longevity of large composite restorations.