CHAPTER 8: CLINICAL TECHNIQUE FOR CLASS V-VI / COMMON PROBLEMS

when occlusal evaluation required for class V restorations

only if occlusal factors are suspected as an etiology for noncarious cervical lesions.

the reason why shade selection for Class V restorations is challenging

because the cervical third of the tooth is typically darker and more opaque.

the isolation methods commonly used in class V restorations

rubber dam with No. 212 retainer or cotton roll with retraction cord.

typical locations for Class V tooth preparations

gingival one-third of the facial and lingual tooth surfaces.

the primary goal of tooth preparation for small/moderate Class V lesions

to restore the lesion as conservatively as possible without preparing 90-degree cavosurface margins.

the shape that walls have in small/moderate Class V preparations

slightly divergent walls with a non-uniform axial surface depth.

How enamel margins typically finished in Class V preparations

they are usually slightly beveled and can be further beveled if needed.

How noncarious cervical lesions (NCCLs) generally prepared

Surface debridement of exposed dentin and roughening/beveling all enamel margins.

the typical preparation design for large Class V lesions extending onto root surfaces

90-degree cavosurface margin at the root with beveled enamel margins.

the recommended bur to initiate large Class V tooth preparations

tapered fissure carbide bur (No. 271) or similar diamond.

the recommended width of the enamel bevel in Class V preparations

at least 0.5 mm at a 45-degree angle to the external tooth surface.

the kind of matrix used in Class V restorations

usually no matrix is needed; however, clear precontoured Class V matrices are available

how composite increments be placed in deep class V preparations

Incrementally with at least two axial increments avoiding simultaneous contact with opposing walls to minimize shrinkage stress.

recommended finishing instruments for removing excess composite on facial surfaces?

Flame-shaped carbide finishing burs or diamonds.

recommended polishing materials after finishing Class V composites

Rubber polishing points/cups

diamond-impregnated polishers

polishing pastes.

the reason why retention more important in large Class V lesions with little enamel

because bonding to dentin or root surfaces is less reliable, requiring extra retention features.

the special dentin condition in Class V lesions the may affect bonding

hypermineralized (sclerotic) dentin, which responds differently to etching and bonding.

How the axial wall be shaped in Class V preparations

Following the original convex contour of the tooth surface.

factors why composite not always be the best choice for Class V restorations

decreased saliva

poor patient motivation

moisture control issues

difficult access

the typical wall configuration and axial surface depth in small or moderate Class V tooth preparations

Divergent wall configuration with an axial surface that usually is not uniform in depth.

the reason why occlusal evaluation generally not required for Class V restorations

because Class V lesions are usually in the cervical third and less affected by occlusal forces, except when occlusal factors contribute to noncarious cervical lesions.

the width that the enamel bevel should be in Class V preparations

at least 0.5 mm, depending on preparation size and esthetic needs.

how the shape of external walls in Class V tooth preparations appear when viewed from the facial side

outwardly divergent walls with all external walls visible.

how the preparation for a Class VI composite restoration be designed

as small in diameter and shallow in depth as possible, entering the faulty pit perpendicularly.

the reason why undermined enamel be left during Class VI preparation

If it is not friable and not in a functional occlusal contact area, it can be bonded to the composite.

should be removed from enamel before completing a Class VI restoration

any stains visible through the translucent enamel to prevent esthetic issues.

types of lesions glass ionomers indicated

low-stress areas

root surface caries (Class V)

slot-like cervical preparations in Class II or III locations without proximal contact.

how dentin conditioned before placement of a conventional glass ionomer

with a mild acid, typically 10% polyacrylic acid, to remove the smear layer and improve adhesion.

the form of glass ionomer materials preferred for mixing

encapsulated materials for triturator mixing or paste–paste materials, which simplify and optimize mixing.

the purpose of resin-based coating applied immediately after conventional glass ionomer placement

to prevent dehydration and cracking of the restoration during initial setting.

the matrix system used with glass ionomer restorations for contouring

Modified Tolemire matrix band with an access hole for injecting material.

the reason why oxygen-inhibited layer important when repairing composite restorations

It allows new composite to chemically bond to the existing composite if added before finishing or contamination.

The surface must be etched, rinsed, and adhesive reapplied before adding new composite.

the key consideration regarding enamel thickness in Class VI defects

Enamel is usually quite thick on cusp tips, so the lesion often remains limited to enamel.

when a matrix be needed for glass ionomer restorations

for Class II or III slot preparations, especially when proximal contouring is required.

the preferred method to polish glass ionomer restorations

using fine-grit aluminum oxide polishing paste with a prophy cup or flexible abrasive discs with lubricant.

how the axial wall be prepared in Class V lesions

it should follow the original contour of the tooth surface, which is convex mesiodistally and sometimes occlusogingivally.

technique that has proper contour using a Mylar matrix in Class IV restorations

creasing the matrix at the lingual line angle to reduce undercontouring.

causes of white line adjacent to the enamel margin

microseparation between composite and tooth

microfracture in marginal enamel

often due to inadequate etching/bonding

fast high-intensity light curing causing polymerization stress

traumatic finishing

management of white lines at the enamel margin

Use atraumatic finishing (light intermittent pressure)

proper polymerization techniques

seal the gap with adhesive

conservatively remove

re-restore the defect.

causes of voids

spaces left between increments during insertion (lamination defects)

composite sticking to instruments during placement.

management of voids

employ careful restorative techniques

repair marginal voids by preparing the area and re-restoring.

causes of weak or missing proximal contacts in Class II, III, and IV composites.

Inadequately contoured matrix band

inadequate wedging

matrix band movement

circumferential matrix for one contact

composite sticking to instruments causing pull-away

matrix band being too thick

solutions to have a strong proximal contacts

properly contour the matrix

ensure matrix contacts adjacent tooth

use adequate wedging

choose matrix systems for specific proximal surfaces

hold matrix during curing

careful composite insertion.

factors cause incorrect shade matching

poor operatory lighting

selecting shade after tooth dehydration

mismatch between shade tab and composite

using wrong shade.

way to improve shade matching

Use natural light when possible

select shade before isolation

cure a sample on tooth to verify

avoid shining operator light on tooth during selection

understand tooth shade zones.

causes of contouring and finishing problems

Inadequate anatomic tooth form (over/under contour)

improper finishing instruments or placement

iatrogenic damage to adjacent tooth structure.

management of contouring and finishing problems

Use proper matrix with correct contours

match embrasures to adjacent teeth

respect outline form

select finishing instruments carefully

avoid rough rotary instruments

protect adjacent teeth

causes of postoperative sensitivity

Aggressive tooth preparation

incorrect adhesive use

failure to use liner/base

microgaps from polymerization shrinkage (especially with high C-factor

aggressive finishing.

managements to reduce postoperative sensitivity

Use gentle tooth preparation with coolant,

proper liner/base use,

correct adhesive application,

apply desensitizers after dentin etching,

insert and cure composite properly

finish restoration carefully.

the reason why fast, high-intensity light curing cause white lines adjacent to enamel margins

It can induce excessive polymerization shrinkage stress leading to microseparation between composite and tooth.

oxygen-inhibited layer

It is the uncured resin surface layer that allows new composite increments to chemically bond without additional etching if repairs are done immediately.

matrix band thickness

this kind of band prevents intimate contact with the adjacent tooth, leading to weak or open contacts

High C-factor

this increases polymerization shrinkage stress, which can cause microgaps leading to sensitivity

the finishing technique that prevent a rough surface

using flexible abrasive discs with lubricant and fine polishing pastes

wedging

separates teeth slightly and prevents composite extrusion, ensuring tight contact and proper contour and prevent weak proximal contacts