This study evaluated the clinical and microbiological long-term effects of 1.25% CHX associated with GIC applied in primary molars using Atraumatic Restorative Treatment (ART) technique. Randomized controlled trial was conducted on 40 children with carious lesions that received ART either with GIC containing CHX or GIC only. Survival rate of restorations was checked at 3 days, 3 months and 1 year after their placement when the unstimulated saliva samples were collected for microbiological assessment of mutans streptococci (MS) counts. Data were analyzed using ANOVA/Tukey or Kruskal-Wallis/Mann-Whitney tests (p <0.05).

ART treatment and follow-up:

Carious lesions were prepared by removing infected dentin with hand instruments. No local anesthesia was administered. Then, the cavities were filled with the press finger technique with one of the randomly selected materials: (1) GIC KetacMolar Easymix® containing 1.25% chlorhexidine digluconate (KM + CHX; n= 41 tooth surfaces) or (2) KetacMolar Easymix® as a control group (KM; n = 66 tooth surfaces). Material excess was removed using carver instrument and the restoration was coated with a layer of petroleum jelly. Multiple-surface cavities were filled after placement of plastic bands and wedges. Both molars (class I and II) and incisors were treated in this study and the same GIC were used for patients who had more than one carious teeth indicated to ART. The children underwent longitudinal clinical follow-up to assess physical condition (partial or complete fractures) of the restoration and the presence of primary or secondary caries at 7 days, 3 months and 1 year, according to ART evaluation criteria by Frencken et al. Children were encouraged and instructed on dental hygiene and received all other necessary oral care.

Microbiological assays:

Unstimulated whole saliva was collected after 7 days, 3 months and 1 year after treatment from each subject by direct expectoration into a 50-ml sterile container for 5-10 min. Pooled supragingival biofilm samples were collected from all buccal and lingual smooth surfaces, except from the interior of the cavities. In order to standardize plaque amount, a sterile plastic disposable inoculating loop with a circular opening of about 1 µL capacity was used for the collection. Collection was stopped when the opening was filled. Biofilm samples were placed immediately into a 1-ml centrifuge microtubes containing Tris-EDTA buffer (10 mM Tris-Hcl, 0.1 mM EDTA, pH 7.5). Collections were performed at least 1 h after feeding. Tubes were transported on ice to laboratory and processed within 2 h.

Inclusion Criteria:

• Good general health
• At least one cavitated dentin carious lesion in primary molars or incisors that had an opening wide enough for the smallest ART excavator access

Exclusion Criteria:

• Teeth with pulpal exposure or the presence of fistula and history of pain were excluded