Hall Technique Dundee Dentistry Good Article

8/10/2019 Hall Technique Dundee Dentistry Good Article

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University of Dundee

The Hall TechniqueA minimal intervention, childcentred approach to managingthe carious primary molar

Copyright Dafydd Evans & Nicola InnesIllustrations copyright Dafydd Evans & Amy McKay

A Users Manual


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The Hall Technique Guide Edition 3: 11.11.10

Contents

How did the Hall Technique come about?

How does the Hall Technique relate to conventional crowns for primary molars?

How does the Hall Technique get around some of these difculties?

What about the soft dentinal lesion?

How does the pulp react to caries?Summary

Is the Hall Tecchnique effective

Clinical outcomes

And is the Hall Technique acceptable to children, their parent and dentists?

Summary of evidence for the Hall Technique

Treatment planning for Hall crowns, and some important information

When can Hall crowns be a suitable management option for carious primary molars?

When is there no need to t Hall crowns?

Summary of indications and contra-indications for the Hall Technique

The appointment for tting the crown

Instruments to have ready

Assessing the tooth shape, contact points/areas and the occlusion

Protecting the airway

Sizing a crown

Loading the crown with cement

Fitting the crown, and rst stage seating

Wipe the excess cement away, check t and second stage seating

Final clearance of cement, check occlusion and discharge

Sealing in caries

The Hall Technique

Final Note

The Hall Technique is a method formanaging carious primary molars wheredecay is sealed under preformed metalcrowns (PMCs) without local anaesthesia,

tooth preparation or any caries removal.

Clinical trials have shown the Hall Technique to be effective, and acceptableto the majority of children, their parents and clinicians. It is NOT, however,an easy, quick x solution to the problem of the carious primary molar. Likeall clinical interventions, for success the Hall Technique requires carefuland appropriate case selection, a high level of clinical skill, excellent patientmanagement and long term monitoring. In addition, it must always beprovided with a full and effective caries preventive programme (see SIGNGuideline 83, downloadable from www.sign.ac.uk)

the background to the Hall Technique;

the evidence behind the Hall Technique;

information on case selection; and

a how to guide on using the Hall Technique.

The Hall Technique will not suit every tooth, every child or every clinician. Itcan, however, be a useful and effective method of managing carious primarymolars. This manual is intended as a guide to developing some skills in theapplication of the technique.

Introduction

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Provision of apreformed metalcrown for a man-dibular secondprimary molar(85) using the HallTechnique; before,and immediatelyafter the crownbeing tted.

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How does the Hall Technique get aroundsome of these difculties?With the Hall Technique, the process of tting the crown is quick andnon-invasive. The crown is seated over the tooth with no caries removalor tooth preparation of any kind, and local anaesthesia is not required.

For decades, conventional teaching hasbeen that all carious tooth tissue shouldbe removed before restoring the tooth;how can leaving caries in the tooth beacceptable?To answer this, it is worth rstly reviewing how and where caries begins. Formany years it was assumed that the combination of a tooth surface, plaqueand sugar would inevitably, after time, result in dental caries. However,despite the universal presence of plaque in the mouth and sugar in the diet,Clinicians will be aware that, except in extreme cases, the majority of toothsurfaces are relatively immune from caries, despite many of these surfacesusually being plaque stagnation areas.

How did the Technique come about?The technique is named after Dr Norna Hall, a general dental practitionerfrom Scotland, who developed and used the technique for over 15 years untilshe retired in 2006. A retrospective analysis of the outcomes for the teeth shetreated in this way was published in the British Dental Journal in 2006 (seebibliography). This showed the technique to have outcomes comparable to

conventional restorative techniques and led us to investigate it further througha randomised control trial (detailed later).

How does the Hall Technique relate toconventional crowns for primary molars?Preformed metal crowns (PMCs), sometimes referred to as stainless steel ornickel chrome crowns, have been used for restoring primary molars since1950, and have become the accepted restoration of choice for the primarymolar with caries affecting more than one surface, with a proven success rateas a restoration. Although popular with specialists, many clinicians nd PMCsdifcult to t using the conventional approach, which requires the use oflocal anaesthetic injections and extensive tooth preparation (see Figure 2).There is also a high risk of damaging the adjacent rst permanent molar whenpreparing a second primary molar for a PMC. For these, and other reasons,PMCs are not widely used in the UK, forming less than 1% of all restorationsprovided for children.

Background to theHall Technique

Preparation of amandibular secondprimary molar (75)for a conventionalPMC.


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Instead, clinically, 99% of dental caries begins on just two sites, whichmake up less than 1% of a tooths surface; the base of ssures, and belowthe contact point of proximal surfaces.


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Plaque is far from the bland, homogenous material it appears to the naked eye.Given time, and a stable environment, plaque will mature into a complex, organisedstructure, with channels and pores. Its bacterial population will shift and change incomposition, with symbiotic relationships developing between some species, whileother species will be gradually squeezed out by their neighbours. In the deeperlayers, organic acids formed as a by-product of bacterial metabolism, will favour ashift in the bacterial composition from non-cariogenic species such as Streptococcus

oralis and Streptococcus salivarius to more cariogenic species such as the mutansstreptococci and lactobacilli. Plaque has been described by Marsh as a city ofslime. This is a useful analogy because just as a city is a complex structure, whosesmooth functioning can be interrupted by a change in the supply of any numberof factors (food, water, oxygen, power, light), so can the cariogenic potential ofplaque be altered by changing the supply of carbohydrates, oxygen, or pH.

DE, with apologies to The Fantastic Voyage

The Hall Technique manipulates the plaques environment by sealing it into thetooth, separating it from the substrates (essentially, nutrition) it would normallyreceive from the oral environment. There is a possibility that the plaque maycontinue to receive some nutrition from perfusion through the dentinal tubules.However, there is good evidence that if caries is effectively sealed from the oralenvironment, the bacterial prole in the caries changes signicantly to a lesscariogenic community, and the lesion does not progress.

What differs between these sites is the degree of shelter they offer to theplaque biolm. The caries susceptible sites of ssures and the area belowcontact points provides plaque biolm with sheltered microniches, allowingit the time and protection to mature to the level where the acidogenic bacteria

(which are present in all plaque, but usually as a relatively low proportion)come to dominate the biolm. As these acidogenic bacteria dominate thebiolm, the pH drops, eventually falling below the critical pH 5.5, at whichhydroxyapatite becomes soluble, and the carious process begins. Once carieshas caused cavitation of the enamel, the availability of sheltered surfacessuitable for plaque colonisation and maturation dramatically increases,and so the caries continues through the tooth. In summary, all plaque ispotentially cariogenic, but needs a sheltered micro-niche for it to becomeactively cariogenic.

The plaque biolmas a City of slime(after Marsh)


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The varying sus-ceptibility of toothsurfaces to dentalcaries, despite thealmost universalpresence of plaque.

Low cariessusceptibility

High cariessusceptibility


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How does the pulp react to caries?Just as it is becoming increasingly clear that dental caries is a dynamic process,it is also being recognised that the dentine/ pulp complex is far from passivewhen exposed to dental caries. Instead, these tissues mount an active defenceresponse from the earliest stages of carious lesion formation in the enamel.Following a response from the immune system, odontoblasts are stimulated to

lay down a layer of reactive dentine in an effort to distance the pulp from theapproaching carious lesion, an effect readily observed, at a gross level,on radiographs.

Clearly, the dental pulp of primary molars has the ability to maintain vitality andmount a defence response to dental caries, even when the dentine is involved.It is possible that the reparative potential of the primary tooth dental pulp hasbeen underestimated.

What about the soft dentinal lesion?It is easy to see how an enamel lesion can be reversed but it can be difcult toimagine how we can inuence a change in the soft dentinal lesion. However,most clinicians will be familiar with this clinical picture. Perhaps because thecavity has become self cleansing, or the childs diet has changed, the caries hasarrested, with the colour changing to dark brown or black. This lesion was once

soft and active, but is now hard and arrested. The evidence that caries can arrestis visible to us on a daily basis, yet we continue to provide management therapies(conventional restorative treatment) based on its complete excision.

Arrested caries onprimary molars - thecaries is dark andfeels hard


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The dental pulpof a primary molarresponding todentinal caries bythe deposition ofreactionary dentine

There is a Cochrane systematic review summarising the clinical evidencearound sealing caries into teeth (see Bibliography). Most plaque is not actively cariogenic. Plaque which has matured in a

sheltered environment to achieve cariogenic potential can lose that potentialif its environment is altered. The bacteria within the community respond tothe environment and in an unfavourable environment, cariogenic bacteriawill not continue to ourish. Effective sealing from the oral environmentcan cause the necessary environmental change, resulting in plaque losingits cariogenic potential for as long as the seal is maintained. The HallTechnique is one method of achieving that seal for primary molar teeth.


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Is the Hall Technique effective?To answer this question, a clinical trial set in nine general dental practicesin Tayside, Scotland looked at outcomes at two years for teeth where a Hallcrown was tted, compared to teeth which had undergone conventionalrestorative treatment.

The trial was a split mouth randomised control design, so teeth were matchedon each side of the arch for type of lesion and extent of caries. The dentiststelephoned a distant operator to be told which tooth to provide a Hall crownfor and which tooth to manage with a standard restoration, and which to trst, in order to reduce any bias in the trial. 132 children were enrolled in thetrial and followed up every year clinically and with bitewing radiographs. Theoutcomes for the 124 patients seen at 2 years (8 patients failed to return for 2year appointments) are shown in Figure 7.

A full report of the clinical trial can be found at

Clinical outcomesAs well as recording episodes of pain, the outcomes were broken into twocategories;

This included the instances of irreversible pulpitis; where an abscess devel-oped requiring pulpotomy or extraction; an inter-radicular radiolucency wasseen on radiographs; or where the restoration was lost and tooth was nowunrestorable

This category included failures which could be resolved by replacing a failedrestoration; new or secondary caries; where the lling/crown had becomeworn, lost or was requiring another intervention to repair it, or where therestoration was lost but the tooth was restorable. It also included instances ofreversible pulpitis which were treated simply by replacing the restoration andnot requiring pulp therapy or an extraction to resolve.

Evidence behind theHall Technique


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2 year results for 124teeth treated withthe Hall Techniquecompared to124 conventionalrestorations in asplit mouth studywith matched carieslesions prior totreatment

Conventionalrestorations

Hall Technique

Summary of evidence for theHall TechniqueThis study showed the Hall Technique to be more effective than the restorationsplaced by the dentists, and an effective restoration in its own right. In addition,the study showed that the Hall Technique was preferred to conventional restorations

by the majority of the children, their parents, and dentists.

And is the Hall Technique acceptableto children, their parents and dentists?In the same clinical trial, the children, their parents/ carers and dentists statedwhether they preferred the Hall or conventional restoration when both procedureswere completed (see Figure 8).


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Patient, carer anddentist preferencesfor Hall Techniqueor conventionalrestorations in asplit mouth studyfor 132 children(264 teeth). Datafrom same study

discussed above.

Conventionalrestorations

Hall Technique

No preferenceexpressed


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Stage 1.Treatment planning for Hall crowns

Hall crowns are not a universal answer to managing all carious primarymolars. They are also not a Lazarus restoration, used to resurrect a tooth

with a poor prognosis, when all conventional techniques have failed, or areimpossible to provide. Instead, with proper case selection, the Hall Techniquecan be an effective management option for primary molar teeth affected bydental caries. The Hall Technique will not suit every dentist, every child, orevery carious primary molar in that child. Other caries management methodsare available, and should be considered, as appropriate. As with every treatmentdecision, clinicians should use their own clinical judgement in deciding whichmethod is appropriate for their patient and within their own clinical capabilitiesto deliver, with consent being obtained from the patient, and parent, beforedelivering that treatment.

To begin with, exclude irreversible pulpalinvolvementA full history and clinical examination, including bitewing radiography,should be carried out. Vitality testing of primary molars with Ethyl Chloride isunreliable. Instead, dentists should use their clinical judgement in assessing

the vitality, and viability, of a dental pulp, based on a thorough assessment,including:

Clinical signs or symptoms of irreversible pulpitis, or dental abscess

Radiographic signs or symptoms of dental abscess

Non-physiological mobility, assessed by placing the points of a pair oftweezers in an occlusal fossa, and gently rocking the tooth bucco-lingually,and comparing with a healthy antimere

An assessment of the extent and activity of a carious lesion, using clinicalacumen to decide if there is likely to be pulpal involvement.

Case selection; using the HallTechnique in clinical practice

There is a buccal sinusassociated with thismaxillary rst primary

molar (64).


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This maxillary secondprimary molar (55) hasan extensive mesio-occlusal cavity, that hasbeen painful, keepingthe child awake atnight. This is indicativeof an irreversible pulpi-tis, or even an abscessdeveloping.

This mandibular rstprimary molar (84)has inter-radicular

pathology, indicativeof a dental abscess.

Here, a mandibularrst primary molar(84) which has givenoccasional pain, butis currently symptom-less, is found to havenon-physiologicalmobility. This, with theDO cavity and his-tory, indicates a dentalabscess.

This mandibular rstprimary molar ( 84) hasa large disto-occusalcavity cavity. Althoughsymptomless, andwith no inter-radicularpathology visible,there is no clear bandof normal dentinebetween the caries andthe pulp chamber. Thepulp is almost certainlynon-viable, and thetooth should have pulptherapy if a crown is tobe placed.


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This maxillary rstprimary molar (54) hasa large multisurfacecavity, with clinicalexposure of a non-vitalpulp chamber. Even inthe absence of symp-toms, this tooth should

be extracted.

This maxillary rstprimary molar (64) hasa pulp polyp. The pulp,although exposed, isvital. In the absence ofsymptoms, and clinicaland radiographic signs,of sepsis, it would notbe unreasonable tosimply monitor thetooth.

This mandibularsecond primarymolar (75) has a largeoccluso-lingual cavitywhich clearly involvesthe pulp chamber.Even in the absenceof symptoms, the

tooth should either bemanaged with pulptherapy or extraction.

However, although thismandibular secondprimary molar (75) hasa similar pulp polypassociated with the me-sial root, there is clearlya sinus associated witha non-vital distal root,and the tooth should bemanaged by extraction.

When can Hall crowns be a suitablemanagement option for carious primarymolars?

Here, the disadvantages of the aesthetics and the temporary bite openingwill generally be counter balanced by the effectiveness of the restoration,for which there is a good evidence base.

This mandibular rst primary molar (74) is appropriate for a Hall crown. Themoderate distal lesion has been diagnosed reasonably early, by appropriateuse of radiographs. The radiograph shows a band of sound dentine betweenthe lesion and pulp, and no intra-radicular pathology.

Hall crowns can also be suitable for the moderately advanced Class I lesionwhere the extent of the cavity would make it difcult to obtain a good sealwith an adhesive restorative material, following partial caries removal.

Clinicians should continue to monitor all primary molars managed with Hallcrowns for signs or symptoms of pulpal disease at every recall visit, just as theyshould for all carious primary teeth managed with conventional restorations.

Irreversible pulpal involvement (discussed above)

Insufcient sound tissue left to retain the crown

Patient co-operation where the clinician cannot be condent that the crowncan be tted without endangering the patients airway

A patient at risk from bacterial endocarditis. In such situations, the toothshould be managed with a conventional restoration which would includecomplete caries removal

Parent or child unhappy with aesthetics. This should become apparentthough at the treatment planning stage when treatment options are beingdiscussed and agreed with the parent and child.


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Mandibular rst pri-mary molar, with earlyto moderate active car-ies on distal proximalsurface; asymptomatic,and with no signs ofpulpal pathology

Moderately advancedocclusal lesions on amandibular second pri-mary molar (85), wheredue to the extent of thecavities, obtaining agood coronal seal witha partial caries removaltechnique might beproblematic


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When is there no need to t Hall crowns?

SummarySummary of indications and contra-indications for the Hall TechniqueIndications and contra-indications for using the Hall Technique for managingprimary molars with carious lesions assessed as at risk of causing pain/ sepsisbefore exfoliation


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Both maxillary andmandibular rst pri-mary molars (54 & 84)although cavitated, areclearly going to

be shed soon, so areunlikely to cause painor sepsis before exfolia-tion.

The mesial cavityon this mandibularsecond primary molar(75) is accessible, andcan be managed

with partial cariesremoval, sealingthe cavity with anadhesive restorativematerial, avoiding boththe aesthetics and bitepropping of a Hallcrown.

The cavitated oc-clusal lesion on thismandibular secondprimary molar (85)could be managed withpartial caries removal,and sealing with anadhesive restorativematerial.

This mandibularsecond primarymolar (75) has non-cavitated occlusallesions which couldbe managed with agood quality, wellmaintained ssuresealant.

This mesial lesion on amaxillary rst primarymolar (64) is arrested.As the lesion is clean-able, there is no needfor any managementoption other thanprevention. However,this does depend on thecarers/child continuingthorough cleaning andthe tooth and lesionmust be monitoredfor signs of the lesionprogressing.

There is insufcienttooth tissue on thismandibular secondprimary molar (75)to allow placementof any restoration.However, the cariesis arrested, the pulp isshining pink throughthe oor of the cavity,and in the absence ofsymptoms, this couldprobably be managedwith prevention, andmonitoring.

Proximal (Class II) lesions, cavitated or non-cavitated

Occlusal (Class I) lesions, non-cavitated if the patient is unable to accepta ssure sealant, or conventional restoration

Occlusal (Class I) lesions, cavitated if the patient is unable to accept partialcaries removal technique, or a conventional restoration

Signs or symptoms of irreversible pulpitis, or dental sepsis

Clinical or radiographic signs of pulpal involvement, or periradicularpathology

Crowns that are so broken down they would be considered unrestorablewith conventional techniques


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The appointment for tting the crownPreparation is everything! The child and parent should be briefed on theprocedure. Children should be shown a crown, and allowed to handle aspare one if felt benecial. Young children sometimes respond to the idea ofthe crown being a shiny helmet, or just like soldiers wear to protect theirheads, or a precious, shiny, princess crown or it being a twinkle tooth.

a) they will have to help, by biting the crown into place when asked to do so

b) the cement will not taste nice and can be a bit like Salt & Vinegar crisps

Stage 2.Fitting Hall crowns; a practical guideAlthough apparently very simple, the Hall Technique requires a condent,skilled approach from the operator if the crown is to be successfully tted. Inaddition, there are some primary molars where, for a combination of reasons,

even clinicians very familiar with the Hall Technique would have difcultysuccessfully t a crown.

Again, common to all clinical procedures, it is important that the clinicianhas a clear understanding of what to do to retrieve a situation which is notproceeding as planned, for example when a Hall crown is not seating properlyonto a tooth or appears to be the wrong size or shape and will not t correctlyover the crown of the tooth. These issues are dealt with at the end of thissection.

Mandibular rstprimary molars withan unusual morphol-ogy, which wouldcomplicate the ttingof PMCs with the HallTechnique should itprove necessary

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The practical aspects of tting a HallCrown can be broken down into thefollowing seven stages:

Fitting a Hall Crown


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Instruments to have ready

Mirror

Straight probe

to remove separators, if used Excavator

to remove crown if necessary, and useful for cement removal

Flat plastic to load crown with cement

Cotton wool rolls for child to bite down on and push crown over tooth, and

to wipe away cement

Band forming pliers can be useful for adjusting crowns, particularly where the primary molar

has lost length mesio-distally due to caries

Gauze to protect the airway and wipe off excess cement

Elastoplast to secure the crown for airway protection

Assessing thetooth shape,contact points/areas and theocclusion

Sizing a crown

Protecting theairway

Loading thecrown withcement

Fitting the crown,

and rst stageseating

Wipe the excess

cement away,check t, andsecond stageseating

Final clearanceof cement,check occlusion(adjusting crownif necessary) anddischarge


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If the separator appears to have fallen out, the inter-proximal area of the gingivashould be inspected to check that the separator hasnt worked its way below thecontact point. Separators are usually brightly coloured to facilitate this.

Often where there is marginal ridge breakdown in one molar, there can bemigration of the adjacent molar into the cavitated area. The picture below showsan example of this. If the missing tooth walls are imagined, they will be seento overlap. This can make placing a Hall crown difcult without making someadjustments to the tooth itself or the crown.

Step 1 of 7:Assessing the tooth shape, contact points/areas and the occlusion

Hall crowns can often be tted successfully to primary molars which are in

contact with adjacent teeth, as there is some elasticity in the periodontal ligamentwhich can absorb the displacement necessary to t the crown. However, muchdepends on the willingness of the child to bite the crown into place, and on theshape of the contact point. Some teeth have very broad contact points, whichcan make tting crowns difcult.

In such cases, placing orthodontic separators through the mesial and distalcontacts can be useful when tting crowns with the Hall Technique, althoughit does mean the patient will have to make a second visit. Two lengths ofdental oss should be threaded through the separator. The separator shouldthen be stretched taut, and ossed through the contact point briskly andrmly until the leading edge only is felt popping through the contact point.The oss should then be removed, and the patient seen 3 to 5 days later forremoval of the separator.

Broad contact pointbetween a maxillarysecond primary molar(65) and the adjacentteeth

The use of orthodonticseparators to createspace for tting a Hallcrown


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Band Forming pliers (a)being used to adjust thecrown margins (b) , andthe effect of rotatingthem 180 degrees topinch in a concavityto accommodate theintruding marginalridge of an adjacenttooth (c).

placement of a temporary restoration to rebuild the marginal ridge andallow a separator to be placed to make space for the crown to be tted; or

Adjusting the crown with band forming pliersa) b) c)

Trying a different crown

Carrying out some tooth preparation; however, this will usually reguirethe use of local anaesthesia

Before tting a Hall crown, check the following two points regarding theocclusion;

1. measure the anterior overbite (in order to assess the degree of proppingof the bite following tting of the crown)

2. check the buccal relationship of the tooth to be crowned with its opposingnumber (to ensure there is no laterally displacing contact following ttingof the crown)

Maxillary rst andsecond primarymolars (64 & 65) withsignicant loss ofmesio-distal dimension(in view of the extentof the dental caries,both of these teethwould require pulptherapy before ttinga PMC).

Use of a mandibularmolar crown to ta maxillary rstprimary molar (54)with signicant lossof mesio-distal width


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Gentle excavationof a distal cavity ona mandibular rstprimary molar (74) isfollowed by placementof a celluloid matrixstrip and a temporarydressing, allowingseparators to be placed10 minutes later


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Step 3 of 7:Sizing a crownSelect different sizes of crowns until you nd one which covers all the cusps,and approaches the contact points, with a slight feeling of spring back. Youshould aim to t the smallest size of crown which will seat.

Be particularly careful not to t an oversize crown to a second primary molarwhere the rst permanent molar has still to erupt; this could increase the riskof rst molar impaction later.

Do not be tempted to fully seat the crown through the contact points beforecementation; they can be very difcult to remove!

Step 2 of 7:Protecting the airwayIt is also important, before the crown is placed, to ensure there will be nodanger of the child inhaling or swallowing a loose crown (the sameprecautions as should be taken when tting a conventional crown).

This is most easily done by sitting the child upright. However, for maxillaryteeth, working with the child seated upright means that the optimum operatorworking position has to be compromised. For mandibular teeth, the operatorcan simply move to the front or side of the child.

There are additional ways of protecting the airway. A gauze swab square canbe placed between the tongue and the tooth where the crown is to be tted.It should extend to the palate and round the back of the mouth in front of thefauces. Alternatively, a piece of Micropore tape, doubled back on itself for partof its length, can be used to secure the crown.

If you are not condent about being able to control the crown at all stagesuntil it is cemented, then do not use the technique.

Protecting the airway

Selecting the correctcrown size


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Step 4 of 7:Loading the crown with cement Following try in, dry the inside of the crown, using the end of a cotton wool roll

Load the crown generously (it should be at least two thirds full) with a glass

ionomer luting cement. Take care ll the crown from the base upwards andensure that there is cement around all the walls. Be careful to avoid airblows and voids

Step 5 of 7:Fitting the crown, and rst stage seatingPlace the crown over the tooth. Fully seating the crown is a key stage! It is notalways easy, and requires a committed, positive approach from the clinician.The child needs to have complete condence that you know exactly whatyou are doing; that what you are asking them to do is perfectly reasonable,and that it will not be uncomfortable. Remember that our research found that,surprisingly, most children do not nd the procedure painful, and prefer it toconventional llings. There are two main methods of seating the crowns:

a) the clinician seats the crown by nger pressure

b) the child seats the crown by biting on it

Loading the crownwith cement

Fitting the crown, andrst stage seating


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A combination of these two methods maybe necessary or preferred. Some clinicians will seat the crown with rm nger pressure alone. For

mandibular teeth, a useful method is to place your thumb on the occlusalsurface of the crown, with the four ngers of your hand placed under the

border of the mandible to spread the force as you apply rm pressure withyour thumb. For maxillary teeth, the childs head may be supported by theback of the dental chair, or sometimes by placing your other forearm gentlyon the top of their head to balance the force applied when tting the crown.

Often, the child will seat the crown themselves by biting it into place. It canbe useful to verbally encourage the child to apply the necessary pressure(Bite hard, like a Tiger! Grrrrr...!), and to rehearse this before tting thecrown. If using this method, be aware that some childrens resolve mightfalter a little, leaving the crown not fully seated. Here, a timely That wasgreat! Now let me just check it for you! Ooh, well done, and Ill just give ita little squeeze..., Excellent! can help.

Some clinicians partially seat the crown until it engages with the contactpoints, allowing the nger to be removed without risk of the crown fallingoff, and the child then being encouraged to bite the crown into place. It mustbe remembered that your working time with glass ionomer cements is limited,and whatever method is used, you must work smoothly and efciently. Crownscannot be seated, no matter how hard either you or the child tries, if thecement has started to thicken.

It is crucial that the orientation of the crown relative to the tooth is checkedeither during, or immediately after, seating the crown. If it does not appearto be going on straight, then you must give the crown some physicalencouragement to go in the correct direction. If it is not possible to seatit then it should be removed before the cement sets.


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Step 7 of 7:Final clearance of cement, checkocclusion and discharge Remove excess cement, ossing between the contacts

Blanching usually disappears within minutes. The occlusal discrepancy(here it is minimal) should resolve in a few weeks.

Measure the degree of bite opening and record in the notes. If excessive,then consider either removing the occlusal part of the crown with a highspeed handpiece, so that it becomes similar to an orthodontic band, orremoving the entire crown.

Check the buccal relationship of the crowned tooth with its opposingnumber. If there is a displacing contact, resulting in a cross bite, thenmanage as for excessive bite propping

Advise the parent and child that the child will probably notice the crownas being high in the bite, but that this will no longer bother them by thefollowing day. If there are any problems, then the child should be broughtback to the surgery.

Give the child a sticker.

Step 6 of 7:Wipe the excess cement away, check tand second stage seating As soon as the crown is tted, the child should be asked to open to allow

the crown position to be checked and excess glass ionomer can be wiped

away.

- With either technique, excess cement will be extruded from the crownmargins, and the taste of this can upset children. In anticipation of this,as soon as the crown is seated, the child should be asked to open theirmouth, and the cement wiped off with a cotton wool roll held ready forthis purpose. If a gauze swab has been used to protect the airway, thiscan be used to wipe away excess cement from the lingual/ palatal sideof the tooth as it is being removed.

- If it is obvious that the crown has not seated, and nger pressure fails toseat it, then it should be removed immediately using the large excavatorwhich you should have placed within easy reach. If you do not workswiftly, you may have to section the crown to remove it.

- If the crown is tting satisfactorily, the child should be asked to bite rmlyon the crown for 2-3 minutes, or the crown should be held down withrm nger pressure as an alternative. Often the crown will seat a littlefurther, expressing more cement. This is possibly due to accommodationto the displacing pressure by the adjacent teeth.

- It is important to maintain rm pressure on the crown until the cementsets, as the crowns can spring back a short way, sucking back the cementfrom the margins and potentially causing breaches in the seal.

Second stage seating

Final clearanceof cement, checkocclusion anddischarge


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7) If tting crowns to second primary molars, particularly in the maxilla,before the rst permanent molars are erupted, keep an eye out for the rstpermanent molars becoming impacted against the crown margin as theyerupt. This can occur even if crowns havent been tted, and there is noevidence from the authors clinical trial that there is an increased risk of this.Nevertheless, if it does occur, it can often be managed with orthodonticseparators if detected early.

8) If a primary molar tted with Hall crown requires a pulp therapy, then thiscan be carried out through the crown without needing to remove it.

9) The Hall Technique is not a t and forget technique. Patients should bereviewed on a normal recall schedule, with radiographic examination inline with current recommendations, and the Hall Technique should beused in conjunction with a full preventive programme.

10) Occasionally a crown will wear through occlusally. If this occurs, it canbe repaired with composite material.

1) Hall crowns should be tted to opposing (occluding) teeth at the sameappointment. The occlusion should have re-established, with bilateralcontacts, before opposing crowns are tted. However, if a primary molaron either side of the same arch needs a Hall crown (or diagonally oppositeteeth in different arches, i.e. a maxillary left primary molar and a mandibularright primary molar), then these (and ideally ) be tted at the sameappointment, as the patient will have two crowns tted with just one episode

of bite propping.

2) In the authors experience, it is usually not possible to t a crown using theHall Technique to both primary molars in the same quadrant at the sameappointment; adjacent primary molars requiring Hall crowns should havethem tted at separate appointments.

3) The crowns used in the research presented here were Stainless SteelPrimary Molar Crowns, cemented with AquaCem, both from 3M/ESPE.Any adjustment of the crowns was minimal, and was limited to re-mouldingthe crown margins in some cases with orthodontic pliers. The margins werenot trimmed on any crowns.

4) Crowns will try to follow the path of least resistance, and so may tilt towardsthe easier of the contacts, making it almost impossible then to ease thecrown through the tight contact. Concentrate on seating the crown throughthe tight contact, and the easy one should take care of itself.

5) If the crown does not seat sufciently, then remove it using the excavatorbefore the cement sets. If the cement has set, a high speed handpiece can

be used to section the crown through the buccal and occlusal surface,following which it can easily be peeled off.

6) Patients and parents should be reassured that the child will be used to thefeeling within 24 hours. It is the authors experience that analgesia is notrequired. The occlusion tends to adjust to give even contact on both sideswithin weeks.

Some additional notes


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The eld of cariology and together with it,the management of caries in the primarydentition, is rapidly changing.

Please let us know of your thoughts and comments regarding the Hall

Technique, or on any other matter relating to management of the cariousprimary dentition.

We also welcome feedback on this manual and how it might be improved.

Dafydd Evans Nicola [email protected] [email protected]

Further copies of this manual can be obtained free of charge by downloadfrom the Scottish Dental website ( )at

The authors would like to thank The Chief Scientists Ofce of the ScottishGovernment, and 3M/ESPE for funding the clinical trial of the Hall Technique,and 3M/ESPE for funding the printing of this guide. The authors would also liketo thank Mr Simon Scott, of the Department of Medical Illustration, Universityof Dundee, for the photography.

Acknowledgements


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Final note


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Sealing in caries

1. Ricketts, D.N., Kidd, E.A., Innes, N. and Clarkson, J., 2006. Complete or ultraconservativeremoval of decayed tissue in unlled teeth. Cochrane database of systematic reviews(Online), 3.

2. Marsh PD. Dental plaque as a microbial biolm. Caries Research 2004; 38(3): 204-11.

3. Riberio, C.C.C., Baratieri, L.N., Perdigao, J., Baratieri, N.M.M., Ritter, A.V., 1999 A clinicaland radiographic, and scanning electron micrscopic evaluation of adhesive restorationson carious dentin in primary teeth. Quintessence International 1999; 30(9):591-9.

4. Paddick, J.S., Brailsford, S.R., Kidd, E.A.M. and Beighton, D., 2005. Phenotypic andgenotypic selection of microbiota surviving under dental restorations. Applied andEnvironmental Microbiology, 71(5), pp. 2467-2472.

5. Going RE, Loesche WJ, Grainger DA, Syed SA. The viability of microorganisms in cariouslesions ve years after covering with a ssure sealant. Journal of the American DentalAssociation. 1978; 97: 455-62.

6. Handelman ,S.L., Leverett, D.H., Espeland, M.A. and Curzon, J.A., 1986. Clinical radiographicevaluation of sealed carious and sound tooth surfaces. The Journal of the American DentalAssociation,113(5), pp. 751-754.

The Hall Technique7. Innes N.P., Evans D.J., Stirrups D.R. 2007. The Hall Technique; A randomized controlled

clinical trial of a novel method of managing carious primary molars in general dentalpractice: Acceptability of the technique and outcomes at 23 months. BMC Oral Health; 7.http://www.biomedcentral.com/1472-6831/7/18

8. Innes, N.P.T., Stirrups, D.R., Evans, D.J.P., Hall, N. and Leggate, M., 2006. A noveltechnique using preformed metal crowns for managing carious primary molars in generalpractice - A retrospective analysis. British Dental Journal, 200(8), pp. 451-454.

9. Innes N.P.T., Evans D.J.P., Stirrups D.R., 2006. Clinical pulpal responses to sealing cariesinto primary molars: 2 year results of an RCT. Caries Research, 40: 327.

10. Innes NPT, Evans DJP. Hall N., 2009. The Hall Technique for managing carious primarymolars. Dental Update, 36:472-478.

11. Evans D.J.P., Innes N.P.T., Stirrups D.R., 2006. Longevity of Hall Technique crownscompared with conventional restoration for primary molars; 2 year results.Caries Research; 40: 327.

12. Evans, D.J.P., Southwick, C.A.P., Foley, J.I., Innes, N.P., Pavitt, S.H. , and Hall, N., 2000.The Hall Technique: a pilot trial of a novel use of preformed metal crowns for managingcarious primary teeth. Tuith http://www.dundee.ac.uk/tuith/Articles/rt03.htm

Bibliography and furtherinformation


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Further copies of this manual can be obtained freeof charge by download from the Scottish Dentalwebsite (http://www.scottishdental.org/) at

University of Dundee

The Hall TechniqueA minimal intervention and childfriendly approach to managingthe carious primary molar

A Users Manual

Text copyright Nicola Innes & Dafydd EvansIllustrations copyright Dafydd Evans & Amy McKay

3M ESPE have sponsored the clinical study on the Hall Technique but any treatment decision involvingthe use of the Hall Technique remains wholly the responsibility of the treating dentist.

Hall Technique Dundee Dentistry Good Article

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