Detoxification of Used Dental Implant Healing Abutments Using An Enzymatic Cleaner – An in vitro Study

Dental implants have become a reliable and popular treatment option for both clinicians and patients to replace missing teeth and restore the patient’s masticatory function, phonetics, esthetics, and self-confidence. A critical step during this process is to create healthy tissue contours surrounding implants with the use of healing abutments (HA). After exposure to the oral cavity, HA are contaminated by saliva and bacteria that may play an essential role in triggering the immune response making them more susceptible to peri-implant disease. Manufacturers recommend each HA be used for single-patient use; however, it is well known that clinicians re-use HA following varying decontamination methods. This study aims to evaluate 4 decontamination strategies utilizing enzymatic agents, available in most clinical settings, to determine the level to which biomaterial can be removed in a group of previously used HA (uHA). Secondly, to determine the degree to which the decontaminated HA are capable of inducing an inflammatory response in-vitro compared to new and sterile HA. Lastly, we aim to compare these 4 enzymatic decontamination techniques to the most efficient non-enzymatic method reported in a previous study (Narvekar, et al 2020). Fifty healthy adult patients with the prior placement of at least one dental implant at the UIC College of Dentistry were recruited for this study. HA were collected following 2-4 weeks of intraoral use, placed in sterile PBS, and distributed randomly into 5 test groups (Group A-E; n = 10/group). Group A: HA were presoaked with enzymatic cleaner foam for 10 minutes, followed by sterilization in an autoclave; Group B: HA were placed in an ultrasonic bath with enzymatic cleaner for 10 minutes, followed by sterilization in an autoclave; Group C: HA were debrided by prophy jet and glycine powder, presoaked with enzymatic cleaner foam for 10 minutes, followed by sterilization in an autoclave; Group D: HA were debrided by prophy jet and glycine powder, placed in an ultrasonic bath with enzymatic cleaner for 10 minutes followed by sterilization in an autoclave; Group E: HA were debrided by prophy jet and glycine powder, followed by sterilization in an autoclave. Ten new, sterile HA served as controls (Group “Control”). HA were placed in cultures containing primary human CD14+ monocyte derived-macrophages (mD-Mφ) for 7 days. Supernatants were collected at 4, 24, 48 hours, and 5 days and cytokine/chemokine profiles were analyzed using a multiplex bead assay. Residual protein concentration was determined by a Micro BCA protein assay while HA from each group were stained with Phloxine B and macroscopically examined for the presence of debris. Results indicate that all test groups presented with differences in the degree of visual decontamination compared to controls, with groups D and E displaying the most effective surface debris removal and reduced protein concentration. However, compared to controls, multiplex assays revealed high levels of inflammatory cytokine secretion up to 5 days from all test groups (A-E) irrespective of the decontamination method used. Of the detoxification strategies, groups D (prophy jet with glycine powder + ultrasonic bath with enzymatic cleaner + steam autoclave) and E (prophy jet with glycine powder + steam autoclave) removed the greatest biomaterial although there was no statistical difference between the two groups while least effective was Group A (enzymatic cleaner + steam autoclave). In conclusion, our study found that compared to new never used HA, decontamination of uHA utilizing enzymatic cleaners failed to reestablish inert HA surfaces and prevent an inflammatory immune response in-vitro. Based on the findings from this study and previous studies, the authors recommend HA be viewed as single-use fixtures until more efficient decontamination protocols are developed.