Lecture 6 Paediatric Dentistry Dr. Israa Ali

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“Restorative dental care for children”

Initially, it was believed that caries is a progressive disease that ultimately

demolished the tooth unless restorative intervention is implemented. This idea is

imprecise as some carious lesions may not progress and, therefore, may not

need restoration. Also, it is nowadays recognized that restorative treatment of

dental caries alone does not stop the disease process. Therefore, contemporary

management of dental caries include identification of an individual’s risk for

caries progression, understanding the disease process for that individual and

active monitoring to assess disease progression and manage with appropriate

preventive programs, supplemented by restorative treatment when indicated.

The tooth should be restored when there are at least clinical criteria of visual

detection of enamel cavitation, visual identification of shadowing of the enamel,

and/or radiographic recognition of enlargement of lesions over time.

The advantages of restoring primary teeth include:

- Removing cavitations or defects to eliminate areas that are susceptible to

caries.

- Stopping the progression of tooth demineralization.

- Restoring the integrity of tooth structure.

- Preventing the spread of infection into the dental pulp.

- Preventing the shifting of teeth due to loss of tooth structure.

When restoring primary teeth, there is a need to consider many factors to choose

the best restorative technique and best restorative material that gives cost-

effective long-lasting results. Of these factors: the child’s cooperation level and

caries-risk level, and the length of time remaining prior to tooth exfoliation.

Rubber dam:

Prior to starting the restorative care for children, it is important to provide good

accessibility and visibility for the operative field in a relatively small area

(child’s mouth). Also, there is a need for good isolation and prevention of saliva

contamination when using most of the restorative material, particularly the

resin-based composites. Therefore, it has been suggested to use the rubber dam

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when restoring primary teeth in children.

The use of rubber dam while restoring primary teeth, and particularly during

pulp therapy, is of particular importance as it offers many advantages:

1- Save time: The time required for placing and removing a rubber dam

(average of approximately 2 minutes) is much less than the time usually spent

during child’s rinsing and spitting.

2- Aid in managing child’s behaviour: Because the rubber dam can control the

child’s lips and tongue, it has been found to help in controlling uncooperative

children and facilitate the operative procedures.

3- Control saliva: Rubber dam helps isolating primary teeth which have large

pulp. During cavity preparation of primary teeth with extensive caries, this will

give a better visualization for the approximation of caries into pulp, and thus,

will aid in a better assessment for the best vital pulp therapy to be used.

4- Provide protection: Rubber dam prevents swallowing or aspirating foreign

objects (filling materials, debris, and medicaments) that are usually used during

various dental procedures.

5- Help the dentist educate the parents: With the rubber dam in place, the dentist

can conveniently show the parents the finished dental work.

Technique of rubber dam placement:

In order to start application of rubber dam, the following armamentarium is

required:

5X5-inch sheets of medium latex (Fig. 6-1).

Rubber dam punch (Fig. 6-2).

Clamp forceps (Fig. 6-3).

Clamps (Fig. 6-4).

Flat-blade instrument.

Dental floss.

Rubber dam frame (Fig. 6-5).

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Figure (6-1): Rubber sheet Figure (6-2): Rubber dam punch

Figure (6-3): Clamp forceps Figure (6-4): Clamps

Figure (6-5): Rubber dam frame Figure (6-6): Position of holes for lower left quadrant

There are four techniques for placing a rubber dam. However, in this lecture, the

technique most commonly used in children will be discussed.

After preparing the above mentioned instruments, the placement of the rubber

dam can be carried out using the following steps:

Give local anaesthesia to the soft tissues surrounding the tooth selected to

apply the clamp on. This step is important as the clamp can cause pain to

the child and make him/her refuse the treatment.

Punch the latex sheet using the rubber dam punch. The rubber dam punch

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usually has four holes on its cutting table (the large punch hole: used for

the clamp-bearing tooth or for permanent molars, the medium-sized

punch hole: used for premolars and primary molars, the second smallest

hole: used for upper permanent incisors, and the smallest hole: used for

primary incisors and lower permanent incisors).

The position of the first hole on the latex sheet, that is usually be for the

clamp-bearing tooth, should be placed at the corner of an imaginary 1 ¼ -

inch square at the center of the sheet. Each corner of this square must be

coincident with the quadrant needed to be isolated. Then, further holes

can be punched to isolate more teeth in the same quadrant. The distance

between the holes should not be too large or too small. The best is to use

the same distance between the holes on the cutting table of the rubber

dam punch as a guide for the distance to be placed between the holes on

the latex sheet (Fig. 6-6).

Select the proper clamp: There are many forms of clamps with different

manufacturers and different symbols or numbers on. However, the basic

rule for selecting the proper clamp is that it must be firmly anchored to

the tooth so that it can be securely seated and will not be dislodged easily

by the tongue, lips, and cheek musculature, or by the tension of the

stretched rubber sheet.

After selecting the proper clamp, a dental floss should be doubled and

securely fastened to the bow of the clamp. This will facilitate retrieval in

the unlikely event of clamp slippage and falling toward the pharynx.

The rubber sheet can be inserted to the previously selected and ligated

clamp using the hole made previously with the punch.

The clamp is then grasped form the two holes on its wings using the

rubber dam forceps.

Both the rubber sheet and clamp are then transferred to the patient mouth

with the assistant holding the upper corners of the rubber dam with her

right hand and the lower left corner with the left hand, while the dentist

holding the lower right corner with his left hand (assuming that both of

them are right-handed) (Fig. 6-7).

The clamp should be secured to the tooth to be isolated and carefully

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positioned at the gingival margin. Then, the forceps can be released.

The assistant can hold the frame. Then, both the dentist and assistant can

tighten the rubber dam and attach its corners to the frame (Fig. 6-8).

The flat blade of plastic instrument can be used to remove the rubber

sheet from the clamp wings and to complete the seal around the clamped

tooth.

If more teeth are required to be isolated, the rubber sheet can be stretched

over them and the excess rubber between the punched holes can be placed

between the contact areas with the aid of dental floss (Fig. 6-9).

When prevention of cervical leakage and extra-retention are required, the

most anterior tooth and other isolated teeth can be ligated using the dental

floss (Fig. 6-10).

Figure (6-7): Transferring rubber sheet & clamp Figure (6-8): Attaching rubber dam to the frame

Figure (6-9): Stretching rubber dam over teeth Figure (6-10): Extra-retention with ligating dental floss

In case of restoration of primary teeth with no anticipation of pulp therapy, the

“slit-dam method” or “trough technique” can be used. It involves making one

long opening in the dam (Fig. 6-11), so that the entire quadrant is isolated

without interseptal dam material between the teeth (Fig. 6-12). This technique is

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quick, easy and reliable; even though it does not provide absolute isolation.

Figure (6-11): One long opening on rubber sheet Figure (6-12): Slit-dam method or trough technique

Cavity preparation of primary teeth:

Because of the morphological differences between primary and permanent teeth

previously discussed in lecture four (p.15), cavity preparation in primary teeth is

not similar to that of permanent teeth. However, there are basic principles that

are needed to be considered when preparing a cavity in primary teeth.

Class I cavity:

The basic principles for class I cavity preparations are:

- Pulpal floor is recommended to be flat.

- Rounded line angles and point angles of the cavity preparation is

advocated.

- The traditional class I cavity preparation is now being replaced by a more

conservative caries excavation and restoration with a combination of

bonding restorative and sealant materials (Preventive resin restoration).

To establish the cavity outlines and accomplish the cavity preparation, the

small, round-ended carbide burs in the high speed handpiece are recommended

to be used. This may involve the use of single bur. Alternatively, aluminium

oxide air abrasion system or laser systems can also be used.

- Incipient class I cavity in a very young child:

For very young child (two years old or less) with small carious lesion in the

central fossa of only one or two first primary molars, minimal restorative

intervention can be carried out in order to prevent further progression of this

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lesion. As the psychological maturity of such child is not established, it is

impossible to develop effective communication, and thus, the child should be

seated on his/her parents lap in the dental chair.

Then, cavity preparation can be performed without the use of local anaesthesia

or rubber dam. This should only involve the removal of caries without

extending to the sound tooth structure. The tooth can then be restored with

amalgam or resin-modified glass ionomer restoration to arrest the caries

temporarily. Alternatively, if the child is cooperative, dentin-bonding agent can

be applied followed by preventive resin restoration.

- Pit or fissure class I cavity:

For minimally decayed occlusal surface (only pit or fissure involvement with

minimal extension into dentin) and with no interproximal caries detected on

bitewing radiographs, preventive resin restoration or sealed composite resin

restoration can be performed.

After drying the occlusal surface, the carious lesion should be inspected

carefully with visual examination by using sharp explorer, mirror and light.

Then, articulating paper can be used to identify the points of occlusal contact

(stress-bearing areas).

The cavity preparation can be started after anaesthetizing the tooth, if necessary,

and isolating it with rubber dam. Conservative removal of the carious pit or

fissure is then carried out with a small high speed handpiece or laser system.

This cavity preparation should involve no extension to the adjacent sound pits

and fissures or to the occlusal contact marks.

The cavity and enamel of the sound pits and fissures is then etched using 37%

phosphoric acid for 20 seconds, thoroughly washed for 30 to 40 seconds, and

completely dried. Then, a thin layer of bonding agent is applied to the cavity

which is then air-thinned and light cured.

The cavity is then filled with light-curing composite, flowable composite, or

resin modified glass ionomer. After curing the composite resin, a light-curing

fissure sealant is applied over the remaining susceptible pits and fissures and

light cured. Finally, high spots should be checked and reduced if present.

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- Deep seated class I cavity:

Cavity preparation in such cases depends on the type of restoration material

planned to be used. If amalgam restoration will be used, the preparation should

involve removal of decayed parts of the occlusal surface in addition to any

unsupported enamel. The caries-affected dentin can be cleaned with large,

round burs or spoon excavator.

On the other hand, if resin-based composite and/or glass ionomer restorations

are to be used, only the carious parts of the occlusal surfaces should be

removed, while the disease-free pits and grooves may only be sealed as part of

the bonded restoration.

Class II cavity:

The basic principles for class II cavity preparation are

- Sharp angles between the pulpal floor and the axial walls of two-surface

preparation should be avoided. Rounded angles are preferred because

they will reduce the stresses and allow a better adaptation of the

restorative material into the extremities of the preparation.

- The width of preparation at the isthmus should be approximately one-

third the intercuspal dimension.

- As the primary molars have broad and flat contact areas with distinct

buccal bulge in the gingival third, the cavity design should have greater

buccal and lingual extensions at the cervical area of the box to clear

contact with the adjacent tooth.

- The axio-pulpal line angle should be bevelled or grooved to decrease the

concentration of stresses and to provide greater bulk of material in this

area, which is vulnerable to fracture.

- It is advisable to slightly reduce and round any sharp opposing cusps that

have the potential to cause fracture of amalgam restorations.

When the preschool child attended the dental office with proximal caries, this is

an indication of an excessive caries activity, and therefore, preventive and

restorative program should be started promptly.

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- Small class II lesions:

Very small incipient proximal lesions may be chemically restored with topical

fluoride therapy provided by the dentist (fluoride gels or varnishes), in addition

to the use of topical fluoride products at home (fluoridated toothpastes and

mouthwashes), as well as improving in diet consumption (no frequent intake of

fermentable carbohydrates). In such cases, the child should be reviewed

periodically and re-assessed for the status of the incipient lesion. If the child

follows the dentist instructions, arrest or remineralization of the carious lesion

may take place. Otherwise, the caries may proceed into dentin.

If there is more distinct class II lesion but with no susceptible pits or fissures in

a relatively low caries risk child, conservative cavity preparation can be

initiated. It involves accessing the cavity through the marginal ridge or the

facial surface and then removing only the carious lesion in the proximal box and

finishing with placing resin-modified glass ionomer material.

- Class II lesions with greater dentin involvement:

Similar to deep class I cavity preparation, preparing class II with deep carious

lesion depends on the material intended to be used later. If amalgam is to be

used, the gingival seat and the proximal walls must break contact with the

adjacent tooth. The angle formed by the axial wall and the buccal and lingual

walls of the proximal box should be 90○. The buccal and lingual walls must

diverge toward the cervical region, following the contour of the tooth. The

occlusal preparation should involve all the caries-susceptible pits and fissures.

However, if no caries present on the occlusal surface, a small dovetail

preparation is required to enhance the cavity retention form. Appropriate liner

or intermediate base can be then placed and a snug-fitting matrix should be

placed prior to inserting amalgam.

If resin-based composite or glass ionomer-based restorative material is to be

used, the cavity preparation for deep class II carious lesion will be similar to

that of amalgam. However, when the occlusal surface has no caries; no

preparation to gain retention will be required. Instead, fissure sealant can be

placed on that occlusal surface as a part of the restorative procedure.

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Class III cavity:

Similar to the proximal caries present on the posterior teeth, proximal caries

present on anterior primary teeth is an indicator of excessive caries activity that

requires comprehensive preventive program.

For maxillary anterior primary teeth with small class III carious lesion that does

not extend extensively into dentin, a conventional class III cavity preparation is

the only need to remove the caries, followed by placement of resin-based

composite or glass ionomer restoration.

If the lower primary incisors have small proximal caries, the management may

only involve disking of the affected proximal enamel (enameloplasty) to open

the proximal contact and remove most, if not all, of the cavitation. This should

be followed by application of fluoride varnish.

- Modified class III cavity preparation:

In high caries risk child, the distal surface of the primary canine is commonly

decayed, especially if it has a contact with the mesial surface of the first primary

molar. Retention of restorative material with the conventional class III cavity

preparation in such cases is not adequate because of the broad contact present

between the distal surface of the primary canine and the mesial surface of the

first primary molar with high gingival tissue present. Therefore, a modification

of class III preparation is required. It involves preparation of a dovetail on the

lingual surface of the maxillary primary canine or on the labial surface of the

mandibular primary canine. This dovetail preparation will act as a lock to

enhance retention of the restorative material.

Class IV cavity (proximal incisal caries):

When the caries on the proximal surface of anterior primary teeth approaches

the incisal edge, the retention of the restorative material will be compromised.

Therefore, additional retention from the preparation of labial and lingual locks

at the cervical third of the cavity is suggested. Bevelling the cavosurface line

angles is also recommended to improve marginal bonding of the restoration.

This might be performed after finishing preparing the class IV cavity and

removing all the caries present. The tooth is then etched and bonded. A properly

placed and wedged matrix can be used to help in placing, shaping, and holding

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the resin-based composite during the curing process.

If the caries is more extensive and involves the incisal portion of the tooth,

crowning of the tooth will be necessary. The crowns could be either direct resin

crowns or stainless steel crowns. For the direct resin crowns, a celluloid crown

(strip crown) can be used as a mold for the resin-based composite after

removing all of the decayed tooth structure.

Although anterior stainless steel crowns are aesthetically unattractive, they may

sometimes be indicated as their aesthetic can be enhance by cutting away the

labial surface and restore it with resin-based composite (open-face stainless

steel crown) or by simply using a preveneered stainless steel crowns. When

using the anterior preveneered crowns, it is suggested to take an impression

prior to preparing the tooth, so that the labial surface of the selected stainless

steel crown can be veneered at the laboratory prior to cementing it on the

second visit (the visit on which caries removal and tooth preparation take

place).

Stainless steel crowns (SSCs) for posterior teeth:

SSCs were first introduced by Humphrey in 1950 to restore children’s and

adolescents’ teeth. They are considered as the most durable restoration that

provides a full coverage for the decayed teeth. Their indications of use in

paediatric dentistry involve the following:

1- Restoration of primary or young permanent teeth with extensive and/or

multiple caries lesions.

2- Restoration of hypoplastic primary or permanent teeth that cannot be

adequately restored with bonded restorations.

3- Restoration of teeth with hereditary anomalies, such as dentinogenesis

imperfecta or amelogenesis imperfecta.

4- Restoration of pulpotomized or pulpectomized primary or young

permanent teeth when there is increased danger of fracture of the

remaining coronal tooth structure.

5- Restoration of fractured teeth.

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6- Restoration of primary teeth to be used as abutments for appliances.

7- Attachments for habit-breaking and orthodontic appliances.

Technique of restoring teeth with SSCs:

The following steps should be followed when preparing a posterior tooth to

receive a stainless steel crown:

Administer a local anaesthesia and place a rubber dam as for other

restorative procedures.

Reduce the proximal surface with a No. 69L bur at high speed; paying an

attention not to damage the adjacent tooth. A wooden wedge may be

inserted between the surface to be reduced and the adjacent tooth surface.

The proximal surface reduction should be nearly vertical so that the

contact with the adjacent tooth is broken. The gingival margin of the

proximal surface preparation should be a smooth feathered edge with no

ledge or shoulder present.

Reduce the occlusal surface and the cusps with No. 69L bur at high

speed; following the general contour of the occlusal surface and leaving

about 1 mm of clearance with the opposing teeth.

Remove all sharp line and point angles with the same bur.

There is no need to reduce the buccal and lingual surfaces as the undercut

on these surfaces will aid in the retention of the contoured crown.

However, it might sometimes be necessary to slightly reduce the distinct

buccal bulge of the first primary molar.

Select the proper crown size by choosing the smallest crown that

completely covers the preparation.

When necessary, contour the crown at the cervical third of the buccal and

lingual surfaces by using crown-contouring pliers with a ball-and-socket

design. This will help adapting the margins of the crown to the cervical

portion of the tooth. Curved-beak pliers can be used to contour the

proximal areas of the crown and develop desirable contact with the

adjacent teeth. Crown-crimping pliers can also be used for contouring.

Try in the crown and check that it is snugly fitted into the preparation and

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properly extended under the free gingival margin. The occlusion should

also be checked to ensure that the crown is not opening the bite or

causing shifting of the mandible into undesirable relationship with the

opposing teeth.

Clean the field and isolate the tooth prior to cementation of the crown.

Fill the crown with glass ionomer luting cement.

Place the crown into the prepared tooth and apply pressure to seat it

properly.

Remove the excess of the luting agent by thoroughly washing around the

crown.

Use a dental floss with a knot to remove the excess luting cement from

the interproximal areas.

Use a flat-blade instrument to ensure that the free gingival margin is not

trapped under the margins of the stainless steel crown.

Alternative (atraumatic) restorative treatment

(ART):

When restoring teeth with the traditional restorative techniques is impossible or

impractical for many reasons, ART is indicated. It involves partial excavation of

the carious lesion using hand instruments, followed by application of fluoride-

releasing glass ionomer or resin-modified glass ionomer. This technique will aid

in preventing pain, reducing infection, avoiding discomfort, and preserving

teeth in individuals who do not have access to regular and conventional oral

health care.

On the other hand, the term Interim Therapeutic Restorative technique (ITR) is

used to describe the technique that is similar to ART but has different

therapeutic goals.

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Restorative materials used in Paediatric dentistry:

Nowadays, there are many restorative materials commercially available to be

used by a dentist. However, selecting the appropriate material for each

individual case will depend on many factors. i.e. degree of caries progression,

ability to isolate the restorative field, level of child cooperation, child’s caries

risk level, time left prior to tooth exfoliation and other factors.

The most commonly used materials in paediatric dentistry are:

Amalgam

Dental amalgam contains a mixture of metals such as silver, copper, and tin, in

addition to approximately 50% mercury. Amalgam has been used widely for

the past 150 years as the most common restorative material for posterior teeth.

However, its use has declined over the past decade due to controversy

surrounding perceived health effects of mercury vapour, environmental

concerns from its mercury content, and increased demand for aesthetic

alternatives.

Despite the existing controversies, the American Academy of Paediatric

Dentistry (AAPD) has recommended to use dental amalgam in the following

situations and where no other alternatives with any controversies are available:

- Class I restorations in primary and permanent teeth.

- Class II restorations in primary molars where the preparation does not

extend beyond the proximal line angles.

- Class II restorations in permanent molars and premolars.

- Class V restorations in primary and permanent posterior teeth.

Resin-based composites:

Resin-based composite restoration has been used for about 50 years as an

aesthetic restorative material. They are increasingly being used in place of

dental amalgam. However, they are more technique sensitive and require longer

placement time. They consist of a resin matrix and chemically bonded fillers.

Filler size affects polishability/aesthetic, polymerization depth, polymerization

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shrinkage, and physical properties. Smaller fillers allow greater polishability

and aesthetic, while larger ones provide strength.

The longevity of resin composites depends on many factors, including operator

experience, restoration size, tooth position, and level of tooth isolation from

saliva contamination.

The American Academy of Paediatric Dentistry has suggested the following

indications and contraindications for composite use in children:

Indications:

- Small pit and fissure caries where conservative preventive resin

restorations are indicated in both primary and permanent dentitions.

- Class I caries extending into dentin.

- Class II restorations in primary teeth that do not extend beyond the

proximal line angles.

- Class II restorations in permanent teeth that extend approximately one

third to one half the buccolinguial intercuspal width of the tooth.

- Class V restorations in primary and permanent teeth.

- Class III restorations in primary and permanent teeth.

- Class IV restorations in primary and permanent teeth.

- Strip crowns in primary and permanent dentitions.

Contraindications:

- Teeth that cannot be isolated to obtain moisture control.

- Individuals needing large multiple surface restorations in the posterior

primary dentition.

- High-risk patients when have multiple caries and/or tooth

demineralization, exhibit poor oral hygiene.

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Glass ionomer restorative cement systems:

Glass ionomers have been used in dentistry as restorative cements, cavity

liner/base, and luting cement for more than 40 years. Glass ionomers have

several properties that favours their use in children, i.e. chemical bonding to

both enamel and dentin, thermal expansion similar to that of tooth, structure,

biocompatibility, uptake and release of fluoride, and decreased moisture

sensitivity when compared to resin composites. However. When these materials

were first introduced, they were brittle, difficult to handle, and exhibited poor

wear resistance; but nowadays, their formulation have been enhanced and

resulted in a restorative materials with better properties. Of these materials is

the resin-modified glass ionomer that shows increasing in strength, reduction in

setting time, as well as improving in handling properties and wear resistance

Again, the American Academy of Pediatric Dentistry has suggested the use of

glass ionomer and resin-modified glass ionomer cement systems in the

following situations:

- Luting cement:

o Stainless steel crowns.

o Orthodontic bands.

o Orthodontic brackets (limited).

- Cavity liner/ base.

- Class I restorations in primary teeth and, in certain cases, in permanent

teeth.

- Class II restorations in primary teeth.

- Class III restorations in primary teeth.

- Class III restorations in permanent teeth in high-risk patient or teeth that

cannot be isolated.

- Class V restorations in primary teeth.

- Class V restorations in permanent teeth in high-risk patient or teeth that

cannot be isolated ideally.

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- Caries control:

o High caries-risk patients.

o Restoration repair.

o ART (Atraumatic Restorative Treatment) and ITR (Interim

Therapeutic Restoration).

Stainless steel crowns (performed metal crowns):

Stainless steel crowns are prefabricated metal crown forms that are adapted to

individual teeth and cemented with biocompatible luting agent. They are

indicated to be used when failure of other available restorative materials is

likely. The indications for their use in Paediatric dentistry have been mentioned

previously in this lecture on p.11

References:

- AAPD. 2015. Guideline on Restorative Dentistry. Clinical Practice

Guidelines. 37 (6). pp. 232-243.

- Berg, J.H. & Croll, T.P. 2015. Glass ionomer restorative cement systems: An

update. Pediatric Dentistry. 37 (2). pp. 116-124.

- Dean, JA. et al. 2015. McDonals and Avery’s Dentistry for the child and

adolescent. 10th edition. Missouri: Elsevier.

- Donly, K.J. & Garcia-Godoy, F. 2015. The use of resin-based composites in

children: An update. Pediatric Dentistry. 37 (2). pp. 136-143.

- Duggal, M.S. et al. 2004. Restorative Techniques in Paediatric Dentistry. 2nd

edition. London: Taylor & Francis.

- Fuks, A.B. 2015. The use of Amalgam in pediatric dentistry: New insights and

reappraising the tradition. Pediatric Dentistry. 37 (2). pp. 125-132.