An In Vitro Analysis of Sodium Hypochlorite Decontamination for the Reuse of Implant Healing Abutments

The reuse of healing abutments (HAs) has become common practice in implant dentistry for economic concerns and the aim of this in vitro study was to assess the effect of sodium hypochlorite (NaOCl) in decontamination of HAs. A total of 122 HAs (used and sterilized [n = 107]; new [n = 15]) were procured from 3 centers, of which 3 samples were discarded due to perforation in the sterilization pouch. For sterility assessment, the used HAs (n = 80) were cultured in Brain Heart Infusion Broth (BHI) and potato dextrose agar (PDA); bacterial isolates were identified in 7 samples. Also, 24 used HAs were stained with phloxine B, photographed, and compared to new HAs (n = 5). A scanning electron microscope (SEM) assessed the differences between 2 sets of HAs, after which the 7 contaminated HAs along with 24 used HAs from staining experiment (total: 31) were subsequently treated with sodium hypochlorite (NaOCl) and SEM images were observed. About 8.75% of HAs tested positive in bacterial culture; Streptococcus sanguis, Dermabacter hominis, Staphylococcus haemolyticus, and Aspergillus species were isolated. Phloxine B staining was positive for used and sterilized HAs compared to controls. The SEM images revealed deposits in the used HAs and although treatment with NaOCl eliminated the contamination of cultured HAs, the SEM showed visible debris in the HA thread region. This in vitro study concluded that SEM images showed debris in used HAs at screw-hole and thread regions even though they tested negative in bacterial culture. The treatment with NaOCl of used HAs showed no bacterial contamination but the debris was observed in SEM images. Future studies on the chemical composition, biological implications, and clinical influence is warranted before considering reuse of HAs.