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Completed

NCT Number: NCT06350578

A Randomized Clinical Trial Comparing Hall vs. Conventional Technique in Primary Molars.

This study aims to assess the comparative effectiveness of the Hall technique (HT) and the conventional technique (CT) for placing Stainless Steel Crowns (SSCs) in primary molars with approximal caries.

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Key information

Age range

3 year–9 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Primary Healthcare Corporation

Doha, Qatar

About this study

Background:

The most common chronic disease in children and adolescents (6-19 years old) is dental caries. The conventional approach to treating carious lesions involves cavity preparation with rotary instruments, followed by restoration using composite resin, amalgam, or stainless steel crowns (SSCs).

Retrospective studies have shown that SSCs have a higher success rate compared to amalgam or resin-based restorations when used for multi-surface caries in primary teeth. Accordingly, the American Academy of Paediatric Dentistry (AAPD) recommends the use of SSCs as the treatment of choice for carious lesions involving more than one surface in high-risk children.

Recently, the Hall Technique (HT) has been used to seal caries in primary molars. This contemporary technique was first introduced in the literature in 2006 by Dr Norna Hall, while working in a high caries-risk area in rural Scotland. The technique is based on straightforward biological principles: the most important layer for caries progression- the superficial plaque layer- is left intact and sealed along with the carious lesion. This leads to the development of a less cariogenic flora within the plaque biofilm, thereby arresting or slowing the caries progression in primary teeth.

The Hall Technique involves cementing an SSC over a carious primary tooth without the use of rotary instruments or local anaesthesia, thus reducing discomfort and improving the child's behaviour during treatment.

Aim:

The study aims to compare the Hall Technique (HT) and Conventional Restoration (CR) using stainless steel crowns (SSCs) in terms of clinical effectiveness, changes in occlusal vertical dimension (OVD), procedural time, child pain perception and cooperation, as well as parental acceptability of both techniques.

Methods/Design:

Approximal dental caries (ICDAS 3-5) in primary molars of children aged 3 to 9 years will be managed using two treatment techniques: conventional restorations (CR) with stainless steel crowns (SSCs) and the Hall Technique (HT). The study will be a binary outcome, non-inferiority randomised trial conducted in a primary care dental clinic setting. The study protocol will follow the Consolidated Standards of Reporting Trials (CONSORT) guidelines for randomised trials of non-pharmacologic treatments. Participants will be randomly allocated to receive SSCs placed using either the conventional technique (CT, control group) or the Hall Technique (HT, experimental group), in order to compare different approaches for managing occluso-proximal caries lesions in primary molars.

Discussion:

This clinical trial aims to determine whether the Hall Technique (HT) provides clinical outcomes that are not inferior to those of conventional restorations (CR) using stainless steel crowns (SSCs) in the management of approximal caries in primary molars. The study will also assess child pain perception, cooperation, and parental acceptability, to support the use of minimally invasive techniques in paediatric dental care.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Participant inclusion criteria:

PHCC paediatric dental patients:

  • Whose parents or legal guardians accept and sign the consent form
  • Who assent to participation.
  • Who aged 3-9 years old.
  • Who exhibit generally cooperative behavior.
  • Who exhibit good general health conditions.
  • Who are presenting at least one occluso-proximal lesion in a primary molar.

Tooth/ carious lesion inclusion criteria:

  • From clinical and radiographic examination, caries limited to the occluso-proximal surfaces and extending to enamel or dentine, cavitated or non cavitated.

Exclusion criteria

  • Uncooperative children who do not understand the procedure or tolerate biting the crown into its position without local anesthesia.
  • Children with special health care needs (SHCN) will be excluded.
  • Children with nickel allergies and sensitivity.

Tooth/ caries lesion exclusion criteria:

  • Tooth with signs or symptoms of dental infection or irreversible pulpitis such as:

A history of spontaneous unprovoked pain, a sinus tract, soft tissue inflammation not resulting from gingivitis or periodontitis, excessive mobility not associated with trauma or exfoliation, furcation/ apical radiolucency, or radiographic evidence of internal/ external resorption (Camp JH 2011).

  • Crowns severely destructed with caries, which considered non-restorable (Innes, N.P 2009).
  • Teeth with single surface (occlusal) caries.

Treatment and study plan

Hall Crown Technique

Procedure

The Hall technique (HT) involves cementing Stainless Steel Crowns SSC on carious primary teeth without using rotary instruments nor local anaesthesia, thus eliminating discomfort, and increasing child's behavior.

Conventional SSC Technique

Procedure

The conventional technique involves complete removal of the carious lesion using rotary instruments and local anesthesia, then restoring the tooth with Stainless Steel Crown SSC.

Primary outcomes

  1. Restoration survival over 12 months

    Time frame: At 1 month, 6 months, 9 months, and 12 months post-treatment

    Success:

    • Satisfactory restoration/crown, no intervention required
    • No clinical or radiographic signs or symptoms of pulp pathology
    • Tooth exfoliated

    Minor Failures:

    • Secondary caries or new lesions detected clinically
    • Crown presents perforation
    • Restoration fracture or wear - intervention required
    • Loss of restoration - tooth that can be re-restored
    • Crown loss - tooth able to be re-treated
    • Reversible pulpitis, which could be treated without the need for extraction or pulpotomy

    Major Failures:

    • Irreversible pulpitis or dental fistula/abscess requiring pulpotomy or extraction
    • Loss of restoration/crown - tooth not capable of being re-restored
    • Periradicular and/or furcation radiolucency
  2. Occlusal Vertical Dimension (OVD) resolution

    Time frame: Assessments will be conducted at baseline (before treatment), immediately after crown placement, and at follow-up visits at 1, 6, 9, and 12 months post-treatment, with particular emphasis on the 1-month follow-up.

    Will be assessed only in the HT group using a millimetre dental probe.

Secondary outcomes

  1. Tooth survival over 12 months

    Time frame: At 1 month, 6 months, 9 months, and 12 months post-treatment

    Teeth with treatments scored as satisfactory or with minor failures will be classified as "successful," while teeth presenting major failures will be considered as "failure for tooth." Data related to the treated tooth will be collected for both groups.

  2. Procedural Time

    Time frame: At the time of treatment visit

    Will be recorded during the treatment visit using a stopwatch for both the Hall Technique and the Conventional Technique.

  3. Participant's cooperation

    Time frame: At the time of treatment visit

    Participant cooperation will be assessed and compared between the two intervention groups using the Frankl Behaviour Rating Scale.

  4. Participant's pain perception

    Time frame: At the time of treatment visit

    Pain perception will be assessed and compared between the two intervention groups using the Wong-Baker Faces Pain Scale (WBFPS).

  5. Parents' perceptions and opinions regarding treatment

    Time frame: At the time of treatment visit

    A five-point Likert scale will be used to assess the following:

    • Child's behaviour during treatment
    • Comfort during treatment
    • Satisfaction with treatment undertaken
    • Dentist's ease of treatment provision
    • Perceived duration of the procedure
    • Willingness to choose the same treatment option again

Sponsors and collaborators

Lead sponsor

Primary Health Care Corporation, Qatar

Other Gov

Registry information

Official study title

Comparative Analysis of Hall Technique and Conventional Method for Stainless Steel Crown Placement in Primary Molars With Approximal Caries: A Randomized Controlled Trial at Primary Healthcare Corporation, Qatar

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Apr 5, 2024
Registry last updated
Sep 25, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.