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

Abstract

The re-use 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. 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 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). Scanning electron microscope (SEM) assessed the differences between the two sets of HAs, following 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 when 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 the reuse of HAs.

Contemporary Sterilization Protocols of Healing Abutments for Reusability: A Systematic Review

“…Although only 30% of the tested HAs in a study showed bacterial presence, the remaining HAs had a strong adherence of biomass (Barreiros et al 2021). Similarly, another study showed presence of no bacterial or fungal contamination on treatment with NaOCl followed by steam autoclaving, but debris was observed in scanning electron microscopy images in some regions of the thread regions primarily attributed to ledge design (Almehmadi 2021).…”

“…Out of 812 articles, after elimination of articles by title/abstract, 20 articles were selected for full-text reading. Fourteen articles were provisionally selected, of which 8 articles fulfilled the inclusion criteria (Wadhwani et al 2016; Wheelis et al 2018; Chew et al 2018; Stacchi et al 2018; Sánchez-Garcés et al 2019; Jain et al 2020; Almehmadi 2021; Narvekar et al 2020), and 6 were excluded (Vezeau et al 2000; Browne et al 2012; Cakan et al 2015; Kyaw et al 2020; Barreiros et al 2021; Jain et al 2021). The PRISMA flowchart depicting the search strategy and characteristics of included and excluded articles is described in Figure 1 and Table 2, respectively.…”

“…In a study evaluating 100 commercially available HAs, 99% of them were found to have some form of residual contamination (Almehmadi 2021).…”

“…In a study evaluating 100 commercially available HAs, 99% of them were found to have some form of residual contamination (Almehmadi 2021). Another study evaluated a newly tested system that included ultrasonic soaking, tumbling by rotating metal pins, and ion pasteurization (Dunn 2002).…”

Microbial Culture and Scanning Electron Microscopic Evaluation of Endodontic Hand Files: An In Vitro Study

“…The files were removed from the bags, washed in deionized water, and air-dried. We observed the files using an oblique light, and the camera (Cannon t31 Rebel) zoomed in on the flutes and cutting surfaces (Figure 1 ) [ 23 , 24 ]. The photographs were uploaded to a computer with 40× magnification and an accelerating voltage set at 15 kV.…”