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

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.