Clinical and Radiographic Comparison of SMART Hall and Conventional Hall Techniques in Children With Carious Primary Molars (SMART HALL)

August 25, 2026 updated by: Rana Amr, Cairo University

Clinical and Radiographic Evaluation of SMART Hall Versus Conventional Hall Technique In Children With Carious Primary Molars: Randomized Clinical Trial.

Brief Summary

Dental caries is one of the most common chronic diseases affecting children, particularly in primary molars, and may lead to pain, impaired function, reduced quality of life, and an increased risk of caries in permanent teeth. Managing caries in young children can be challenging because of behavioral and developmental factors, highlighting the need for minimally invasive, child-friendly treatment approaches.

The Hall Technique is an effective minimally invasive approach that uses stainless steel crowns to seal carious primary molars without caries removal, tooth preparation, or local anesthesia. It has demonstrated high clinical success and good patient acceptance. However, concerns remain regarding the activity of residual bacteria within deeper carious lesions.

The Silver-Modified Atraumatic Restorative Technique (SMART) incorporates silver diamine fluoride (SDF), which has antibacterial and remineralizing properties, before restoration and sealing. This may provide additional caries-arresting and antibacterial benefits compared with the conventional Hall Technique.

Although both techniques have shown promising clinical outcomes, there is limited evidence directly comparing the SMART Hall technique with the conventional Hall Technique, particularly regarding long-term clinical and radiographic outcomes. Therefore, the proposed study aims to evaluate whether adding SDF to the Hall Technique improves treatment success in carious primary molars. The findings may help identify an effective, minimally invasive, and child-friendly approach for managing dental caries in pediatric patients.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Dental caries continues to have a major effect on children's oral health and it is one of the most common chronic disorders impacting children globally. According to recent epidemiological research, carious lesions in primary molars are quite common in young populations, incidence rates among preschoolers and early school-aged children are estimated to be between 40 and 90%.

Consequences of this high incidence include pain, illness, impaired chewing function, a decreased quality of life, and an increased risk of caries in permanent teeth. Managing carious primary molars is further complicated by the behavioral and developmental challenges that pediatric patients often experience. This requires the use of kid-friendly, efficient, and minimally intrusive treatment techniques with less chair time and higher caries arrest.

The most popular restorative option for fixing and preserving the remaining structure of severely decayed or damaged teeth is stainless steel crowns. In 1947, they were first introduced to pediatric dentistry, first described by Engel, and then made popular by Humphrey in 1950.

For severely decayed primary teeth, stainless steel crowns (SSCs) are now a necessary restorative option. These crowns have prefabricated anatomy and come in a variety of sizes; to properly fit each tooth, they must be trimmed or contoured. This initial adjustment usually does not result in pain or discomfort, though it may cause variations in occlusal contact points.

Rationale of the Study:

Management of dental caries in primary molars remains a persistent challenge in pediatric dentistry, particularly when treating young or anxious children where conventional restorative procedures may not be well tolerated. In recent years, there has been a shift toward minimally invasive approaches that aim to control disease progression while reducing patient discomfort and the need for extensive operative procedures.

The Hall Technique is known as the gold standard method for managing carious primary molars without caries removal, local anesthesia, or tooth preparation. By sealing the carious lesion under stainless steel crown, the technique deprives cariogenic bacteria from their substrate, so this arrests the lesion progression. Despite its high success rates, concerns remain regarding the complete inactivation of residual bacteria, especially in deeper lesions.

On the other hand, SMART technique incorporates the use of silver diamine fluoride (SDF), with its antibacterial and remineralization characteristics. SDF has been shown to arrest caries effectively by inhibiting bacterial growth and promoting the formation of more resistant tooth structure. Combination of SDF with Conventional Hall Technique approach may provide an additional therapeutic benefit by enhancing bacterial control before sealing the lesion and the tooth.

Although both approaches are individually supported by evidence, there is a lack of well-designed randomized clinical trials directly comparing the combined SMART Hall technique with the conventional Hall technique in primary molars. Specifically, limited data are available regarding their comparative clinical and radiographic outcomes over time.

Therefore, this study will be made to fulfill this gap in the literature by evaluating whether the addition of SDF to the Hall technique offers a measurable advantage in terms of treatment success. The findings of this study may contribute to improving clinical decision-making and optimizing minimally invasive treatment strategies in pediatric dentistry.

Review of literature:

Dental caries is one of the most common chronic diseases affecting children around the world, especially in primary molars. Modern pediatric dentistry has moved towards less invasive and more natural methods focused on saving tooth structure and keeping pulp healthy. Among these, the Hall Technique and the Silver-Modified Atraumatic Restorative Technique have become more popular as alternatives to traditional restorative methods.

The Hall Technique is a less invasive method that seals cavities under preformed stainless-steel crowns without removing decay, using local anesthesia, or preparing the tooth. This approach isolates harmful bacteria from their food source, stopping the progression of the decay. Clinical studies have shown consistently high success rates, better cooperation from children, and positive acceptance from both patients and parents. Additionally, crowns used in the Hall Technique have provided better long-term results compared to traditional restorations, in terms of less pain, fewer infections, and a reduced need for additional treatments.

Recent research has supported the effectiveness of the Hall Technique for treating dentinal caries in primary molars. A randomized clinical study with an 18-month follow-up found that teeth treated with the Hall Technique remained symptom-free, functional, and successful on X-rays, with no major failures noted. Furthermore, a 24-month study comparing variations of the Hall Technique showed high survival rates and clinical success, reinforcing its reliability in pediatric dental settings. These results underline the technique's durability and effectiveness, especially for multi-surface lesions.

However, the Hall Technique has limitations, such as concerns about aesthetics due to the metallic crowns and its inapplicability in cases where the pulp is involved or there's significant structural loss. To address some of these issues, alternative minimally invasive methods like SMART have been developed.

The SMART technique combines the antibacterial properties of silver diamine fluoride (SDF) with a restorative approach. SDF is applied to arrest bacterial activity and arrest the progression of dental caries, followed by restoration of the tooth with glass ionomer cement under the stainless-steel crown. This method not only stops further decay but also restores tooth function and promotes remineralization.

Recent controlled trials have compared the effectiveness of SMART with traditional restorative techniques. A 24-month clinical trial found no significant difference in restoration success rates between SMART and conventional approaches; however, SMART showed much higher patient satisfaction and better management of behavior. Similar studies from 2023 to 2025 indicate that SMART can effectively manage deep carious lesions, providing benefits like shorter treatment times, minimal invasiveness, and improved child cooperation.

Emerging evidence also suggests that SMART could improve clinical outcomes when combined with biological methods. A 2025 randomized clinical trial comparing one-visit and two-visit SMART procedures showed promising success rates, indicating flexibility in clinical use while still being effective. Additionally, research looking into post-treatment pain and behavior found that SDF-modified Hall techniques led to less discomfort and better cooperation among young patients.

Although both the Hall Technique and SMART are minimally invasive, there is limited direct evidence comparing the two. Ongoing randomized clinical trials are set to compare their clinical and radiographic results, treatment times, and patient experiences in children aged 3 to 9 years. These studies are crucial to find the best and most acceptable treatment for managing carious primary molars.

In summary, current literature supports both the Hall Technique and SMART as effective minimally invasive methods for managing carious primary molars. The Hall Technique shows high clinical success and durability, while SMART provides additional antimicrobial benefits and better acceptance from patients. Nonetheless, more well-designed randomized clinical trials directly comparing these two techniques are necessary, especially regarding long-term outcomes. This gap in evidence highlights the need for the current study.

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Rana Amr Abd El-Tawab Shafik A Shafik
  • Phone Number: +0201001522599 +02 01124702071
  • Email: ramr04320@gmail.com

Study Locations

  • Egypt
    • Cairo Governorate
      • Cairo, Cairo Governorate, Egypt, 11511
        • Faculty of Dentistry, Cairo University, Cairo, Egypt.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Patient-related inclusion criteria:

    1. Children aged 4 to 8 years old.
    2. One surface carious lesion.
    3. No signs and symptoms. (e.g., no tooth pain)
    4. Presence of one or more primary molar(s) with deep carious dentine.

Tooth-related eligibility criteria:

  1. Presence of active cavitated carious lesions that can be removed by an excavator are accessible with hand instruments.
  2. Vital pulp with symptom-free or reversible pulpitis.
  3. No spontaneous/prolonged pain or percussion pain.
  4. No abnormal mobility or signs of infection (swelling, fistula, abscess).
  5. Sufficient tooth structure for stainless steel crown retention.
  6. Deep caries lesions radiographically extend through at least the inner half of the dentine.
  7. Presence of a clear band of normal-appearing dentine between the carious lesion and the pulp in a bitewing radiograph.
  8. More than 2/3 of the roots remaining.
  9. No internal/external resorption or periapical/furcation pathology.

Exclusion Criteria:

  • 1. Presence of severe systemic medical conditions (e.g., uncontrolled diabetes, immunodeficiency disorders).

    2. Use of medications known to interfere with dental treatment or healing, such as anticoagulants or immunosuppressants.

    3. Presence of extensive dental caries or additional oral pathologies requiring urgent or specialized dental care beyond the scope of the study.

    4. Patients allergic/sensitive to nickel since PMCs contain nickel. 5. Cases with significant space loss or reduced mesio-distal width due to interproximal caries (making crown fitting difficult).

    6. Unaffected dentine between lesion and pulp cannot be confirmed clinically/radiographically.

    7. Presence of extensive dental caries or additional oral pathology requiring urgent or specified dental care beyond scope of study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: SMART Hall Technique, SDF before Conventional Hall Technique.
SDF is applied before the Conventional Hall technique to arrest the bacterial action.
Other: SDF with stainless steel crown
Will apply SDF before applying the stainless steel crown with glass ionomer cement without caries removal or local anesthesia.
Active Comparator: Conventional Hall Technique
Hall technique will be applied using glass ionomer cement under the stainless steel crown without SDF.
Other: Conventional Hall Technique
Applying stainless steel crown with glass ionomer cement without SDF and no need for preparation or caries removal or local anesthesia.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Clinical evaluation
Time Frame: 12 months

  1. Presence of pain on percussion:

    Measuring device: Clinical examination. Measuring unit: Binary (If present: Yes , if absent: NO)

  2. Presence of swelling:

    Measuring device: Clinical examination. Measuring unit: Binary (If present: Yes , if absent: NO)

  3. Presence of fistula:

    Measuring device: Clinical examination. Measuring unit: Binary (If present: Yes , if absent: NO)

  4. Presence of mobility:

Measuring device: Clinical examination by the back of the mirror and asking the patient if there is pain on percussion.

Measuring unit: (If present: Yes , if absent: NO)
12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Radiographic Evaluation
Time Frame: 12 months
  1. Presence of widening of periodontal membrane space. Measuring device: DIGORA ® for windows software. Measuring unit: Binary (If Present: Yes, If absent: No)
  2. Presence of periapical radiolucency. Measuring device: DIGORA ® for windows software. Measuring unit: Binary (If Present: Yes, If absent: No)

  3. Presence of furcation involvement:

    Measuring device: Radiographic failure score (0-3), (0) indicates no radiographic failure and (3) indicates presence of obvious radiographic failure.

    Measuring unit: Binary (If Present: Yes, If absent: No)

  4. Presence of pathological root resorption. Measuring device: DIGORA ® for windows software. Measuring unit: Binary (If Present: Yes, If absent: No)
12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Cairo University

Investigators

  • Study Director: Rania Abdallah Nasr Nasr, Professor of Pediatric Dentistry, Faculty of Dentistry, Cairo University.
  • Study Director: Norhan Omar Ahmad El-Gebaly El-Gebaly, Lecturer of Pediatric Dentistry and Public Health.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

November 1, 2026

Study Completion (Estimated)

October 1, 2027

Study Registration Dates

First Submitted

August 21, 2026

First Submitted That Met QC Criteria

August 25, 2026

First Posted (Actual)

August 28, 2026

Study Record Updates

Last Update Posted (Actual)

August 28, 2026

Last Update Submitted That Met QC Criteria

August 25, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • SMART Hall

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Sharing Time Frame

12 months

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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