## 2 Materials and Methods  
Study design, sample size, and ethical aspect: A triple blinded randomized controlled trial with the split-mouth design was conducted among 90 school children aged 5 to 9 years old. The study period was 24 months. The children included in the study were selected by using the simple random sampling lottery method from the outpatient clinic of the Department of Pedodontics and Preventive Dentistry, and after screening surrounding schools. Selected children belonged to a low to moderate socio-economic background with limited dental health care access. The sample size was determined using the parameters of previous ART systematic review and meta-analysis, which reported 94% survival for single surface primary posterior teeth ART restorations [23]. A clinically expected 12% survival difference between conventional GIC and CHX-modified GIC was considered with \(\hat{\epsilon}\) error of 0.05, and power of 80%. A total of 75 single surface primary molars for each treatment group was required, which was rounded to 90 per group considering the dropouts (20%). Intraoral periapical radiographs were used to assess the pulpal involvement whenever necessary. Ethical clearance was obtained from the institutional review board (Protocol number- CODS/IRB/14/2017/01). Before treatment, written informed consent was obtained from all parents/ guardians. The inclusion criteria to participate in the study are explained in Table 1.  
The material used: A split-mouth design was used for ART restorations with conventional GIC (GC Fuji IX, Tokyo, Japan) and modified GIC with chlorhexidine incorporation, assigned randomly to contralateral sides using the lottery method. Modified GIC was prepared by the addition of one wt/wt percent of CHX diacetate (RM1659-25G, HiMedia Laboratories, Mumbai, India) into the powder of the conventional glass ionomer (GC Fuji IX, Tokyo, Japan) by the geometric dilution method. One thousand mg of Fuji IX GIC was proportioned on a mixing pad and weighed, to which 10 mg (one percent) of CHX was added. Both the material was available in an identical container. CHX modified GIC was prepared by a non-operating denti and labeled the container as I and II, respectively for conventional GIC and CHX modified GIC for effective blinding of the operating denti \begin{table}
\begin{tabular}{l l} \hline \hline  & \(\bullet\) & Healthy participants without any history of medical condition or disease. \\  & \(\bullet\) & Presence of at least two cavitated dentine carious lesions on the occlusal surface of primary molars situated on different sides of the jaw with a natural antagonist. \\  & \(\bullet\) & Carious lesions were moderately deep, involving enamel and dentin, and accessible to hand excavation using ART procedure. \\  & \(\bullet\) & Definite or likely pulpal exposure or an associated abscess, pain or swelling, and adjacent soft tissue lesion. \\ Exclusion criteria & \(\bullet\) & Teeth with enamel crack or fracture \\  & \(\bullet\) & Teeth with a developmental disorder. \\  & \(\bullet\) & Presence of abnormal oral habits. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Inclusion and exclusion criteria for participants’ enrolment in the study. Cavity size estimation: The size of the cavity was measured in terms of depth, mesiodistal, and buccolingual dimensions before the restoration of the cavity. The depth, mesiodistal width, and buccolingual width of the cavity were categorized into four groups (<2 mm, 2.1-3 mm, 3.1-4 mm, and >4 mm). The depth of the cavity at the deepest part was measured using a sterilized K-file with a rubber stopper and accurately recorded using a high-sensitivity dental caliper. The widest mesiodistal and buccolingual width of the cavity was directly measured using high sensitivity dental caliper after completion of cavity preparation. Cavity size volume was calculated and was divided into six groups (0-9.9 m\({}^{3}\), 10-19.9 m\({}^{3}\), 20-29.9 m\({}^{3}\), 30-39.9 m\({}^{3}\), 40-49.9 m\({}^{3}\), and >50 m\({}^{3}\)).