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Pediatric Lecture # 7

Done by: Katreen Suleiman

- The doctor was reading the slides most of the time, she just explained some points, but didnot add anything new..

- This lecture is very easy. Good luck.**************************************************************************************************

Today we are going to talk about:

** Stainless steel crowns (posterior teeth)

** Composite resin-strip crowns (anterior teeth)

Types of extra-coronal restorations in pedo include:

1. Stainless steel crowns (posterior teeth)2. Composite resin-strip crowns (anterior teeth)3. Labial veneers: which are either:

*Composite or porcelain (porcelain is seldom used in pediatric dentistry)

*Direct (you apply them immediately) or indirect (you put them on a cast then you cement

them.

4. Onlays(usually composite, and can be gold and cast)

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- They are performed restorations that are useful in restoring primary and permanent teeth.- Was described by Engel in 1950, then by Humphrey in 1950.- SSC are made of:

1. Iron 2. Carbon 3. Nickel 4. Chromium** Chromium: Improves corrosion resistance.

** Nickel: resists corrosion and adds strength.

- It comes in a kit with different sizes.

Morphology of primary teeth:

Morphology of primary molars differs from permanent teeth by having its greatest convexity at

cervical 1/3 of crown.

Which means theres an undercut in that area.How do we put the crown?

The cervix of SSC is flexible. So once it reaches the maximum convexity, the cervix of the

crown well stretch, and then it clicks (closes) again under the undercut. And itll be

retained by the undercut.

Stainless steel crowns (SSC)

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Enamel and dentine of primary molars are proportionally thinner than in permanent teeth& are susceptible to caries attack.

So if caries starts on Es and 6s at the same time, itll spread &reach the pulp much faster on

the Es.

Primary pulp is large, with prominent pulp horns & situated close to mesial surface of toothcrown, especially in mandibular primary molars, placing exacting demands on cavity

design.

The SCC for permanent molar is designed so that it closely resembles the anatomy of a 1stpermanent molar tooth & it also obtains its retention mainly from the cervical margin area.

Indications of using SCC:

As you noticed from the treatment plans, we use SCC often at the pediatric clinic.

1. After pulp therapy (pulpotomy and pulpectomy).pulpotomy: patial removal of the pulp.

pulpectomy: its like RCT.

2. Restorations of multisurface caries, like when you have a mesial lesion, and an occlusallesion and a buccal one, and even when you have a class II lesion, its better to place a

crown. So in this case you restore the tooth with glass ionmer cement, and then place aSSC.

When comparing SSC with amalgam restoration, amalgam will fail 7-8 times more than

a crown.

3. Patients who have high caries risk, so you need something durable for these patients.Or when you are working under GA, you need something that will last for the lifetime of

the primary tooth.

4. Primary teeth with developmental defects, like enamel hypoplasia, we need to protectthe tooth from structure loss.

After several studies, it has been found that these crowns have a very high success rate

& durability, whereas amalgam restorations are more likely to fail, especially if you

have a proximal box extending beyond the anatomic line angles.

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5. Fractured teeth, so if you have a fracture or a crack in the tooth, the SSC will hold thetooth together in a better way.

6. Teeth with extensive wear (attrition, erosion, bruxism,where sever tooth structure lossoccurred).

7. Abutment for a space maintainer.

Contraindications for SSC:

There are no or minimal contraindications for using these crowns.

1. Inability to fit a crown. Like when we dont have an adequate, or no enough tooth structureto hold a crown.

2. A poor behavior of a patient, but this problem has been solved by using GA.3. Teeth approaching exfoliation within 6-12 months, we dont place a SSC for them.

Indication for SSC for permanent teeth:

The same as in primary teeth, but the difference is that in primary teeth we use SSC as a

permanent restoration, until the tooth exfoliates.

A question commonly asked by the parents, is it a permanent restoration? Will it be replaced

later?

=> So you have to explain to them that this is a permanent restoration, we never interfere with it,

or change it. It stays there until the tooth exfoliates. It falls with the tooth, because the crown is

cemented to the tooth. Or if the tooth is extracted later, its beextracted with the tooth.

But in permanent teeth:

1. its an interim restoration, like a temporary restoration, for a certain period of time, andthen when the patient becomes an adult, they can change it into something more esthetic,

or if the crown no longer fits or becomes high, because teeth keep erupting with time.

2. When financial considerations are a concern, as an interim, permanent performed metalcrowns are useful as a medium-term, economical restorations.

Many adult patients come to the clinic, asking for a SSC crown to be placed on a pulp-

treated tooth, because they cannot afford a porcelain crown.

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3. Teeth with developmental defects. SSC are beneficial for restoring occlusal height &reducing sensitivity caused by wear of tissue, enamel and dentine dysplasia, amelogensis

imperfect, dentinogenisis imperfect,dentinal desplasia, and almost all dental anomalies in

young patients.

4. Disabled patients and patients with poor oral hygiene.

Other considerations:

1. Patients with high caries risk. SSC are perfect for them.2. Restoration longevity. How long do you want the restoration to last?

When you want the restoration for more than 2 years, or when the patient is less than six

years old, evidence suggests its best to place a SSC, because itll last for alonger period.

3. Cost effectiveness. Class II amalgam is less expensive than SSC, but its more likely to failthan SSC. Some studies found that amalgam is 4 times more likely to fail; other studies

found that its 8 times over 5 years.

Advantages of SSC:

Extreme durability and longevity; so If you do it the right way, youll never have toreplace it again.

Relatively inexpensive (here we are talking about cost effectiveness); the patient willpay more, but itll last for a longer time.

Subjected to minimal technique sensitivity during placement; so when preparing acrown or placing it, we do not need moisture control. The only moment when we need

moisture control, is during cementing of the crown.

Offers the advantage of full coronal coverage; especially for patients who suffer fromsevere sensitivity and dental anomalies, you solve many problems for them, like sensitivity

and loss of tooth structure, loss of vertical dimension, esthetic problems. So the patient will

be very comfortable after placing these crowns.

Disadvantages/ Risks associated with stainless steel crowns:

Periodontal concerns; poorly fitting SSC or poor oral hygiene, which means plaqueaccumulation, and calculus formation.

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or when you dont remove the excess cement after placing the crown, these cement

residues will cause plaque accumulation, gingival inflammation, and make the crown

uncomfortable for the patient.

Nickel allergy; it used to be 70%, nowadaysits much less, its around 9-12%. And theincidence is about 1% due to contact dermatitis.

So if you find that the patient is sensitive for the crown you have to remove it.

Esthetics: these crowns are not esthetic, so they are used for posterior teeth (Ds & Es),where nobody can see them.

Nowadays, some companies (like 3M, easy crown) make SSC covered with an esthetic layer

made of porcelain or ceramic on the buccal surface, and they are NOT as expensive as

porcelain crowns, but the crown wont be as flexible as it was on the buccal surface,

because this ceramic material is brittle. Whereas in SSC, when can fix it, bind it, or twist it in

order to make it fit, because none of these crowns will exactly fit to the tooth of the patient.

Success Rate:

SSC rarely needs to be replaced.If we compare SSC to amalgam class II, 16% of cases in amalgam class II are replaced while

in SSC only 3% of cases need to be replaced.

Which means amalgam is replaced 5 times more than SSC.

Method of placement:

Before starting with any procedure, everything needs to be readyand this is important in everyprocedure you perform in the clinic..

So when you are going to do fissure sealant, the doctor is going to ask you..

What instruments and stuff have to be ready? (like cotton roll, gauze, acid itch, sealant, the light

should be ready, the suction, tongue depressoretc.).

Please pay attention to this.. Its important.

So for SSC you need to have:

1. Scissors2. Crimping pliers (we dont have them at our clinics, so we use Adams pliers instead)3. Burs:

tapered diamond (needle bur)for opening the contact

flame-shapedfor occlusal reduction

Stone(green stone)/Rubber busfor polishing

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** This is a picture of crown scissors, they are slightly curved anteriorly.

They are used when we need to cut the margins of the crown. They are sharp and able to

cut stainless steel.

SSC crimping- plier

used for crimp margins of SSC

Crown contouring plier

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Steps of placing SSC:

1. You give Local anesthesia. Apply rubber dam. And you put gauze on the patients tonguewhen doing a trial. Because the crown might slip and go into patients throat...

Its a precaution that you should applywhenever you are trying crowns, or placing

anything in patients mouth.

2. Restore the tooth with GIC where applicable.For example, if you have a class II cavity, you remove all the caries and place GIM.

3. Reduce the occlusal surface by about 1.5 mm.4. Cut interproximal contacts.5. Try SSC, mesiodistal (MD) width of the crown, should be equivalent to the MD width of the

tooth.

When you open the crown kit, youll find that its divided into upper and lower, left and

right. And each side has Ds and Es. (For primary teeth).

Whereas for permanent teeth theres a special kit that contains 6s.

Adams plier, like the one we

use in orthodontics.

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6. Crown should sit no more than 1 mm subgingvily.7. Now when you find the right size for the tooth, you fill the crown with cement (about 3/4th

of the crown), and you dry the tooth well, and place the crown and cement it.

8. Wipe off excess cement or wash it with water. And tell the patient to keep biting on thecrown. For few minutes.

You can block the Ionmer by putting some Vaseline around the margins for about 3

minutes during setting period.

**The doctor said that well start practicing on doing SSC & pulpotomy on extracted teeth in

the summer semester, and its better to start collecting primary molars from now.

- Lets say you are trying a SSC,and you try size 2, and find it small, then take size 3, and find it too big, what do you do in

this case?

We take size 2, and cut 1 mm of the margin (cervix), itll become size 2.5, so make it bigger,then we polish it using the stone bur, and crimp it using Adams plier, then we place it.

- If SSC is impinging on the gingiva, cause severe blanching, then cutting of the margin maybe required.

- If you are placing two crowns (for example, on E and D), we start from distal to mesial.So we put the E first, and then the D.

Stainless steel

crown kit

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And you have to flatten the interproximal surfaces (for the adjacent mesial and distal

surfaces), because if you have adjacent class II, then you have tooth loss, and space loss, so

there wont be enough space to put two adjacent crowns with their interproximal bulges

next to each other.

- Note that after you cut the margins of SSC, crimping and polishing are required.- Optimum adaptation of SSC includes:

checking crownslength and the shape of crown margin.

Length of crown:The crown has to be 1 mm subgingivally.

Shape of crown margin:

- The D crown; looks like a stretched-out S.- The E crown; looks like a smile.

- Interproximally, both have a shape of a frown (sad face).

- ** The doctor talked about the outline of the crown on both D and E teeth.Please refer to the table in the slides.

- Another conservative method for placing the crown, and this method is not mentioned inpediatric books, it was found by a pediatric dentist ( couldnt hear the name), it was

mentioned in her papers about dental anomalies (dentinogenisis imperfect), she talked

about using separators.(The same ones used in orthodontics).

Separators are placed between teeth, they cause pressure and separate teeth, and in this

case you dont have to remove any tooth structure with burs.

We put the separators for (??? min 37:00), and later, when you remove them, therell be a

1-2 mm space. You put a crown, and after 1-2 hrs. the space will close by itself.

This method is used to conserve tooth structure, especially in patients with MIH (molar

incisor hypominiralization).

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Composite resin strip crown (CR strip):

crowns using celluloid crown forms are a method of restoring primary anterior teeth.

- Its filled with composite, and put on anterior teeth.

Success Rate:

- It was found that teeth treated under GA, and restored with composite, had a very highfailure rate (30%).

CR strip crowns had failure rate of (51%), while SSC had failure rate of (8%).

Composite Resin Strip Crowns

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- SSCs have the highest success rate among all types of restorations.- CR strip crown retention rate is around 88%.- Causes of failure:

1. Loss of all or part of composite.2. Color matching.3. Adaptation.4. Poor retention5. Caries.

- The procedure is technique sensitive.- Any lapses in patient selection, moisture control, tooth preparation, adhesive application &

CR placement can lead to failure.

** The doctor only read the slides and did not add any new info.

So you can go back to the slides, or continue reading from the script.

Indications for using strip crown:

1. Caries is present on multiple surfaces.2. The incisal edge is involved.3. There is extensive cervical decalcification.4. Pulpal therapy is indicated.5. Hypoplasia.

Contraindications to strip crowns:

1. Inability to control moisture & hygiene especially if poor OH and marginal gingivitis ispresent.

2.

Insufficient tooth structure remaining to hold the restoration.3. Insufficient enamel tissue for the composite to adhere to.4. Deep bite and anterior cross bite.5. Uncooperative behavior by the child.

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Advantages of strip crowns:

1. They are the most esthetic restorative option for carious primary teeth.2. Ease of repair if the crown is subsequently chipped or fractured.

Disadvantages of strip crowns:

1. Technique sensitive, hemorrhage or saliva on the tooth will interfere with the bond, andhemorrhage can interfere with the shade or color of the material.

2. Need for adequate tooth structure to remain after caries removal to ensure sufficientsurface area for bonding.

3. Their durability over extended periods of time may be of concern.4. Color match of these crowns with adjacent teeth may be significantly reduced when placed

upon teeth that have undergone pulpectomy treatment and have been obturated with

iodoform paste.

5. The size of the crowned tooth may become bulkier.

Steps of CR strip crown placement:

1. Oral hygiene the most important.- It is advantageous to obtain maximum oral hygiene prior to commencement of treatment.- Parents should be instructed and convinced that they bear partial responsibility for success

of treatment by preparing their childs gingiva for the procedure.

- Instruct the patient to use clorohexdine at least two weeks prior to treatment.2. Strip crown preparation:- Crown pierced with sharp explorer at mesial or distal incisal angle (corner of the crown) to

create a vent for escape of any air bubbles entrapped in the crown.

- After vent preparation, gingival margins should be cut.3. Rubber dam placement:- Using slit-dam technique.- Caries removal & liner placement.

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4. Crown placement & curing.- Each crown is filled with composite and placed separately.- Remember: we do acid itching & place bonding agent before placing the crown.- In case there was bonding agent on gingiva, you have to remove it.

5. Minimal filling is highly recommended.- Try not to fill the whole crown, 3/4this enough.- Place the crown, remove the excess, and then light cure it.

Q: after curing composite, how do we remove the crown?

A: using the excavator, just push it, and Ill get out, because it doesnt stick to the composite.

Thank you

Done by: Katreen Suleiman