Remnant oral biofilm and microorganisms after autoclaving sterilization of retrieved healing abutments

The Reuse of Healing Abutments: A Questionnaire-Based Survey

Healing abutments (HA) are used in second-stage implant surgery to create the optimal peri-implant environment. Despite being a component intended only for short-term use, it remains in the mouth for a few weeks to several months and stays in close contact with organic debris, intraoral fluids, and bacteria. Reusing the HAs modifies their surfaces, expands the coating layer's porosity, and promotes bacterial colonization at the HA-implant interface in addition to the previous contamination. Therefore, the study's goals were to determine the frequency of HA reuse, examine the sterilizing and disinfection techniques employed, and examine the factors that contributed to the dental professionals in the Indian state of Maharashtra utilizing these components again when placing dental implants. For the study, 150 dentists who worked in the field of implantology were chosen. An online questionnaire issued via email and WhatsApp was used to collect data, which started in January 2023. The survey was designed to store the demographic information and responses of the participants, and it was made available through Google Forms. By the end of February 2023, the responses had been gathered. Tables and graphs were used to present the study outcomes that were based on the statistical analysis. The analysis employed the Chi-square test, with a p-value of 0.05 deemed statistically significant. There were 150 answers in all, with 44% women and 56% men. Merely 7.4% of participants do not reuse healed abutments, compared to 92.6% who follow this procedure. The respondents were also asked about the number of times they reused the HAs, 69% of the implantologists reused the same component countless times, while 31% reused it only once. All the respondents reported sterilizing the HAs before reuse and the method used for sterilization was autoclave (96.4%) and UV chamber (3.6%). In response to a question concerning informing patients about the reuse of HAs, 77.6% of implantologists stated they do not interact with patients, while only 22.4 reported doing so. Implantologists in the state of Maharashtra, India reuse HAs and use heterogeneous methods for disinfection and autoclave sterilization.

Could Dental Material Reuse Play a Significant Role in Preservation of Raw Materials, Water, Energy, and Costs? Microbiological Analysis of New versus Reused Healing Abutments: An In Vitro Study

AIM

The objective of this in vitro study was to compare reused and sterilized versus new healing abutments to assess whether a decontamination and sterilization process performed on resued healing abutments was sufficient to remove residual proteins. The two groups were comparable with respect to patient safety.

MATERIALS AND METHODS

During the period from September 2022 to October 2023, healing abutment screws were selected and divided into two groups according to whether they were new or previously used in patients. The samples were subjected to a decontamination and sterilization protocol, and results from sample sterility evaluation and assessment of surface protein levels were recorded.

RESULTS

The obtained results revealed a significant difference in the OD562 nm values between new and reused healing abutment samples. The assay demonstrates how treated healing abutments were still contaminated by residual proteins.

CONCLUSION

Within the limitations of the present study, although from an infectious point of view sterilization results in the total eradication of pathogens, surface proteins remain on reused healing abutments.

Effect of chemical and electrochemical decontamination protocols on single and multiple-used healing abutments: A comparative analysis of contact surface area, micro-gap, micro-leakage, and surface topography

INTRODUCTION

Although the combined use of chemical and electrochemical decontamination protocols can completely remove contaminants from the surfaces of one-time used healing abutments (HAs), their effectiveness in multiple-used HAs remains unknown. We aimed to investigate the effect of reused HAs frequency on the implant-HA contact surface area, micro-gap, microleakage, and surface topography following chemical and combined chemical and electrochemical decontamination protocols.

METHODS

Ninety bone level titanium implants were assembled with 90 bone level HAs, in which 80 contaminated HA samples were collected from human participants. The retrieved HAs were randomly divided into two groups according to the cleaning protocol: ultrasonication with 5.25% NaOCl solution for 15 min and steam autoclaving (group I); ultrasonication with 5.25% NaOCl solution for 15 min, followed by electrochemical cleaning and steam autoclaving (group II). The control group (group III) comprised 10 new unused HAs. The cleaning protocol was applied after each insertion as follows: (a) single-use and cleaning, (b) double-use and double cleaning cycles, (c) triple-use and triple cleaning cycles, and (d) more than triple-use and more than triple cleaning cycles. The contact surface area and micro-gap were assessed with micro-computed tomography scanning technique, microleakage test using 2% methylene blue staining, surface morphology with scanning electron microscopy, and surface elemental composition with energy-dispersive X-ray spectroscopy analysis.

RESULTS

Group Id exhibited the smallest contact surface area. The values of the micro-gap volumes and microleakage were significantly different (p < 0.001) in the descending order of Id > Ic > Ib > IId > Ia, IIa, and III. Morphological evaluation of Groups IIa, IIb, and IIc revealed that residual biological debris was optimally removed without altering their surface properties.

CONCLUSIONS

Chemical and electrochemical decontamination protocols are more effective than NaOCl cleaning methods, particularly for multiple consecutive uses with better decontamination levels, which decreases micro-gap volume and microleakage without surface alterations. Although the use of combined decontamination protocols for the contact surface area at the implant-HA interface showed comparable results with the control, change in the contact surface area was observed following the NaOCl cleaning methods. Therefore, titanium HA reuse can be considered in multiple times, if they are cleaned and sterilized using combined chemical and electrochemical decontamination protocols.

Efficacy of combined chemical and electrochemical decontamination treatments on contaminated healing abutments and their effect on surface topography: An in vitro study

OBJECTIVE

To evaluate the efficacy of four decontamination protocols on contaminated healing abutments (HAs) and their effects on surface topography.

METHODS

Eighty contaminated single-use HA samples collected from human participants were stained with phloxine B and examined microscopically. The retrieved HAs were randomly divided into four test groups: (1) Autoclaving only (AU), (2) 5.25% sodium hypochlorite (NaOCl) + AU, (3) Electrochemical treatment (EC) + AU, (4) NaOCl + EC + AU, and positive control (contaminated without any treatment). Four new unused HAs served as negative controls (NC). The surface features were analyzed using stereo microscopy (SM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and optical profilometry.

RESULTS

The lowest decontamination efficacy was observed for the AU group. The NaOCl + AU and EC + AU groups effectively removed residual contamination, whereas EC + AU showed better decontamination results than NaOCl + AU. SM, SEM, and EDS analyses revealed the best decontamination efficacy in the combined NaOCl + EC + AU group compared to the other groups. Surface roughness (Sa), developed surface area ratio (Sdr), and texture-aspect ratio (Str) in AU, NaOCl + AU, EC + AU, and NaOCl + EC + AU groups were not statistically significant compared to the NC group.

CONCLUSIONS

The combination of NaOCl with subsequent EC can remove soft and hard deposits from the surface of HAs compared to NaOCl alone and EC alone, without altering the surface topography of HAs.

Comparison of Mechanical Resistance to Maximal Torsion Stress in Original and Nonoriginal or Compatible Prosthetic Implant Screws: An In Vitro Study

Micromovements of the implant-abutment connection influence peri-implant bone preservation. The maximal torque after a cycle of implant prosthetic screw tightening using original components of different manufacturers and replicas produced by other companies is evaluated and quantified in this study. A total of 30 Mis Seven® standard platform implants and 30 interfaces were used, and 30 standard platform screws were tested, 10 Mis®, 10 Iconekt®, and 10 Exaktus®. The screws were tightened with an MIS® torquemeter until their respective fracture, and the fracture point was measured through the equipment's load cell, CS-Dental Testing Machine®. The screws were analyzed under an Olympus® SZ61 microscope. The fracture points were recorded and compared among all samples. To compare the mean values of the fracture torques, t-tests were performed using the reference values associated with each brand and the sample results. The variable “Place of Fracture” between the original Mis® brand and the Exaktus® replica compared to the Iconekt® replica presented a statistically significant difference (p < 0.001). When analyzing the variable “Fracture Torque,” although it was verified that the replica screws (Iconekt® and Exaktus®) had a lower maximum torque, 65.11 Nm and 62.89 Nm, respectively, compared to the original Mis® brand (70 Nm and 69 Nm), there were no statistically significant differences p > 0.05. Nonoriginal screws did not present different fracture resistances compared to the original Mis® brand screws. The fracture site of Iconekt® screws showed a different pattern compared to the other brands.

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

INTRODUCTION

Although healing abutments are designated for single use by most implant manufacturers, it is common practice for clinicians to reuse healing abutments. However, there is a lack of adequate references that describe detailed sterilization protocols for reuse of healing abutments.

OBJECTIVES

The purpose of this systematic review was to compile, organize, and describe the most common techniques for the sterilization of healing abutments and their efficiency in eliminating traces of microorganisms.

METHODS

An electronic search in 5 different databases was performed, including the National Library of Medicine (MEDLINE via PubMed), Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Google Scholar from January 2000 to December 2020. Search variables included were dental implant, healing abutment, contaminate, contamination, reuse, and sterilization. Studies reporting with a minimum sample size of 10 healing abutments (5 per group) published in the English language were evaluated. Risk of bias assessment was elaborated for included investigations.

RESULTS

In total, 812 articles were identified, of which 8 were included in the analysis. Steam autoclave was the most widely used form of resterilization. Not a single protocol, however, was able to achieve 100% virgin surface of the healing abutments.

CONCLUSION

Although reuse of dental implant healing abutments is a cost-effective measure in dental practice, thorough surface decontamination followed by resterilization is highly recommended before reuse.

KNOWLEDGE TRANSFER STATEMENT

With consideration of cost and patient preference, results of this review would be useful in knowing various sterilization protocols for reusing healing abutments that could lead to more appropriate therapeutic decisions.

One-Abutment One-Time Effect on Peri-Implant Marginal Bone: A Prospective, Controlled, Randomized, Double-Blind Study

Objective: To evaluate the peri-implant hard tissue change at 6 and 12 months after implant placement between definitive abutment placed at the same time of implant surgery, never removing it, and healing abutment disconnected and reconnected three times until the placement of the final rehabilitation. Material and methods: Each partial edentulous patient could receive between 1 and 4 platform-switched implants in the posterior regions. If the implants had primary stability—implant stability quotient (ISQ) equal to or greater than 50, they were randomized to the test group with the abutment inserted at the same time of implant placement (DA) or to the control group, receiving a healing abutment (PA). At 6 and 12 months after surgery, data related with vertical bone level changes (primary outcome) and other clinical parameters (implant mobility, bleeding on probing, probing depth, plaque index) were assessed. Results: 53 implants were included in the trial and completed 12 months follow-up (overall survival rate: 100%). All implants achieved primary stability, with an average ISQ value of 80.9 on the day of surgery. From surgery to 6 months, the mean bone loss was 0.14 ± 0.18 mm for the DA group and 0.23 ± 0.29 mm for the PA group, without statistical significance difference. Between 6 and 12 months, the mean bone loss was 0.14 ± 0.21 mm for the DA group and 0.21 ± 0.27 mm for the PA group, also without statistical significance between the two groups. There were no statistically significant differences (p = 0.330) in total bone loss after 12 months between the control and the study groups. Conclusions: The one abutment one time protocol has at least an equivalent effect on the peri-implant bone level changes when compared with the use of healing abutments that are disconnected and reconnected at least three times.

Evaluation of residual contamination on reused healing abutments

OBJECTIVES

The purpose of this study is to evaluate residual contamination of healing abutments sterilized by dealers of dental implant companies.

MATERIAL AND METHODS

Healing abutments collected from dealers of different implant companies were randomly numbered, and they were examined for visible deformation and contamination on the abutment surface, packaging errors, and presence of a sterilization indicator. The healing abutments were stained with a dye solution for contamination detection and evaluated by dividing into different regions. The presence of residual contamination was examined through photographic images taken from the healing abutments and the data obtained were recorded. Pearson's chi-square analysis was used to evaluate the relation between implant brands and contamination status. Significance was evaluated as p <0.05.

RESULTS

Visible residual contamination was detected in approximately 31% of the healing abutments. After the staining procedure, in the visual assessment of the stained surfaces, residual contamination was found in at least one region of all healing abutments except one (n=176, 99.4%). The most intense staining was seen in the screw driver hole (n=172, 97.1%), body (n=113, 63.8%), occlusal (n=107, 60.4%), screw (n=79, 44.6%), and connector (n=72, 40.6%) regions, respectively. A significant relationship was found between the brands and the contamination status (p <0.05).

CONCLUSION

The reuse of healing abutments is not suitable, as it does not ensure optimum cleaning and sterilization, and it is not possible to eliminate contaminants completely.

CLINICAL RELEVANCE

Despite the economic benefits of multiple use of healing abutments, disadvantages should be carefully evaluated by clinicians.