A Study Comparing the Hall Technique and Conventional Stainless-Steel Crowns in Carious Primary Molars : Clinical Outcomes, Anxiety, Time, and Cost-Effectiveness

Design This research study will utilize a RCT (randomized controlled trial) design with equal group allocation (two arms). This study's aim is to determine if the Hall technique (HT) for treating carious posterior teeth in children was superior to using stainless steel crowns (SSC). Study outcomes are classified into clinical \& radiographic success; patient anxiety; treatment duration; and cost-effectiveness of treatment. CONSORT guidelines are used for conducting this study and an equivalency study design is chosen because the literature indicates both treatments have similar levels of success.

Setting and Recruitment

This study will be conducted at the Pediatric Dentistry clinic at faculty of Dentistry - MTI University. Subjects will be recruited from among children presenting to the outpatient pediatric dentistry clinics (routine dental checkups and/or for dental caries treatment). This setting has a lot of socio-economic diversity as well as a sizeable number of untreated cavity lesions and is therefore an ideal setting to evaluate the simplification and minimization of dental treatment. Eligible subjects will be examined by calibrated examiners using appropriate tools. Informed consent for the participation will be obtained from the parent(s)/guardian(s) and the participating children provided an assent.

Participants and Eligibility Criteria

Only patients aged between 5-8 years old will be included in the study. The following criteria is used to determine eligibility to be part of the study:

Only participants with one or two asymptomatic, vital primary molars following completion of treatment, will be able to participate in the clinical study .The posterior teeth may have multi-surface caries within the proximal and occlusal surfaces of the teeth, either one or both surfaces have been involved with caries and results in complete coronal coverage of the tooth.

The posterior teeth included must show evidence of caries on x-rays (ICDAS 0-3), but with no evidence of pulp involvement/radicular pathology.

All included teeth must be able to be restored and possess sufficient structure for retention of a preformed metal crown (PMC).

Participants will be eligible if they demonstrate cooperation (i.e. Frankl behaviour rating 3-4) during examination/anesthesia/surgery.

Exclusion criteria:

• Any clinical symptoms or signs associated with pulpal pathology which could include sinus tract, spontaneous pain, tenderness to percussion or pathological mobility.
• Radiographic evidence of pulp involvement, furcation radiolucency or pathological root resorption exceeding one-third (1/3) of the root length were also considered.
• There are certain medical or systemic conditions/contra-indicators for routine dental treatment.
• Target teeth which have been previously restored have additional requirements.
• A follow-up appointment cannot occur because the parent/guardian will not be able to bring the child in for any follow-up appointments is another issue.

These criteria are created according to published guidelines regarding the Hall Technique and SSC placement .

Sample Size Calculation

For our sample size calculations, we used G*Power software (3.1) using the primary analysis approach (among other methods). Surviving teeth from either treatment group had been reported in the literature to have 94-98% chance of survival at 24-month follow-up. With a 10% allowable difference in survival rates, 80% power, and a significance level of 0.05, accounting for a 20% dropout by the end of follow-up, we estimated that at least 96 teeth in each of the two treatment groups would be necessary in order to achieve statistical validity; therefore, we involved 200 subjects with a total of 200 treated teeth (100 HT treated teeth and 100 conventional treated teeth).

Randomization and Blinding

An independent non-treatment administrator will conduct simple randomization using random.org computer software-generated random number sequences. Sequentially numbered, sealed opaque envelopes, will be opened just before treatment, providing allocation concealment. Because the nature of the interventions made operator and participant blinding impractical, outcome assessors and the statistician will be blinded to group allocation to minimize assessment and analysis bias. Participants self-reported their anxiety to minimize observer bias.

Interventions

All treatments will be performed by a single calibrated pediatric dentist (operator calibration kappa > 0.85 for caries diagnosis and crown placement).

Hall Technique (HT) Group

The Hall technique will be done according to the Welbury protocol (2017). No anesthesia, no caries removal, no preparation of teeth was done in any of the cases.

Selection of Crown size: the smallest possible size of the stainless-steel crown (3M ESPE Stainless Steel Crowns) that fit passively was used.

Placement of Orthodontic separators: used 3-7 days before crowns were placed where contacts were tight between the teeth.

Placement of Crown cementation: glass ionomer luting cement (Ketac Cem 3M ESPE) was used; before placing the crown on a tooth, it was placed on the tooth using fingertip pressure and then after that, using the patient biting down onto it.

Removal of excess cement: all excess cement around the crown was removed with floss and hand instruments/de-bonding scalers.

Assessment of occlusion: Although high initial occlusal discrepancy was accepted, according to Welbury (2017); Hussein et al (2020), these discrepancies would spontaneously self-correct with time, as the dento-alveolar structures would adapt to the newly placed crown.

Parents/participants were informed about the expectations of transient occlusal changes and were given oral hygiene and dietary instructions.

Conventional Technique (CT) Group

Conventional SSC placement was carried out according to established pediatric dentistry protocols . Local anesthesia (2% lidocaine with 1:80,000 epinephrine) was administered when required.

1. Complete caries removal using slow-speed round burs and hand excavators.
2. Pulp protection with calcium hydroxide liner for deep lesions, when indicated.
3. Tooth preparation including occlusal reduction (1-1.5 mm), proximal slicing, and rounding of line angles.
4. Crown selection, trimming, contouring, and crimping.
5. Cementation using glass ionomer luting cement.
6. Final occlusal adjustment to ensure proper articulation.

Both groups received standardized post-operative oral hygiene instructions and fluoride varnish applications.

Outcome Measures Primary Outcome:

• Clinical and radiographic success (crown survival) assessed at 1, 2 and 3 months.
• Major failures: Irreversible pulpitis, pulpal necrosis, abscess formation, inter- radicular radiolucency, or crown loss requiring replacement.
• Minor failures: Reversible pulpitis, crown perforation, or development of new caries requiring intervention (Santamaria et al., 2015).

Pre-specified Outcomes:

1. Patient anxiety will be assessed using the Facial Image Scale (FIS) pre-treatment, immediately post-treatment, and during follow-ups.
2. Treatment time will be measured in minutes using a stopwatch.
3. Cost-effectiveness will be evaluated through direct cost analysis and calculation of the incremental cost-effectiveness ratio (ICER) based on quality-adjusted tooth years (QATY).
4. Gingival and plaque indices will be recorded using the Löe and Silness Gingival Index and Plaque Index.
5. Occlusal status is assessed clinically at each follow-up visit.

Follow-up and Data Collection

Participants were assessed again after 1 month, two months, and three months . Reminder telephone calls will be made to minimize participant dropout rates. Data will be collected using a standardized data collection form and a secure electronic database.

Prior to data collection, all examiners will be calibrated using a set of standard clinical photographs and radiographs.

Statistical Analysis

SPSS software version 26.0 will be used to perform the analysis, using the intention to treat principle for analyzing the data. Kaplan-Meier method will be used for survival curve analysis for the patients recruited for the study. Independent t-tests or Mann- Whitney U test will be used for analyzing continuous data, and Chi-square or Fisher's exact test will be used for analyzing categorical data. ICER with sensitivity analysis will be used for cost-effectiveness analysis, and a p-value of less than 0.05 will be set as statistically significant for the study.