Discussion : Evaluation of decontamination methods on implants (5)|palmerah.implantgigi.com

However, the rotary stainless steel instrument created numerous shallow scratches, especially on machined surface implants. John et al. compared the supragingival plaque cleansability of a rotary titanium instrument to that of a stainless metal curette on contaminated titanium disks. The residual biofilm area left on implant treated with the rotary titanium instrument was significantly lower than in the stainless metal curette, and the surface alteration of the titanium disks could not be shown in SEM analysis. Although the cleansability of the rotary stainless steel instrument in the present study is superior and advantageous, the downside of the surface alteration is an issue to consider.

It has been previously stated that the alteration of the implant surface during cleansing may attenuate biocompatibility. However, several clinical studies revealed the considerable treatment effect even though there was certain expected damage on the implant surface. Therefore, it is assumed that the most important consideration for treating peri-implantitis in the clinical setting should be to improve the cleansability of any instrumentation to effectively remove biofilms irrespective of implant surface alteration.

Analysis of bacterial CFU count

In the present study, the gauze soaked in saline, rotary stainless steel instrument, and air abrasive demonstrated significantly greater cleansability to remove biofilms compared with the ultrasonic scaler on rough and machined surface implants. Generally, gauze soaked in saline appeared to possess the best cleansability among all the tested decontamination methods although there was no significant difference among the three methods with the greatest cleansability (G, Rot, Air). In the analysis between the two surfaces, surface characteristics significantly influenced total CFU counts between rough and machined surface implants when testing the control and gauze soaked in saline and ultrasonic scaler. Overall, machined surface implants tended to show lower CFU counts than rough surface implants apart from those treated with the Er:YAG laser.

Charalampakis et al. examined the effectiveness of mechanical and chemical decontamination methods using titanium disks contaminated intraorally. They employed four decontamination methods: gauze in saline, chlorhexidine, delmopinol, and an essential oil mixture. The authors discovered there was no significant difference in CFU counts among the four methods. In the present study, our findings were in line with their report regarding the difficulty of removing biofilms from contaminated titanium surfaces. Even mechanical decontamination with a chemical agent did not yield any significant difference in CFU counts in their study. It has also been revealed that chemical agents in conjunction with mechanical debridement on contaminated implants could not augment a significant treatment effect. This is one of the reasons why we focused on mechanical decontamination methods to cleanse the contaminated implant surfaces.

Sahrmann et al. tested three instruments (ultrasonic scaler, Gracey curette, and air abrasive device with glycine powder) on rough surface implants stained with indelible ink used as artificial plaque. There was a statistically significant difference in terms of stain removal rate. The air abrasive device showed the best result among the tested instruments. The result of this study is in line with our result showing the superiority of the air abrasive compared with the ultrasonic scaler.

Widodo et al. evaluated the efficacy of different methods used to cleanse titanium disks contaminated by S. aureus biofilm in vitro. They used the following methods: (i) rinsing with phosphate-buffered saline, (ii) rinsing with chlorhexidine digluconate 0.2%, (iii) application of photodynamic therapy (iv), use of a cotton pellet, (v) use of a titanium brush, and (vi) the combination of a titanium brush and photodynamic therapy. The results showed that the use of a titanium brush with/without photodynamic therapy was more effective in reducing the bacterial load on both polished and rough titanium implant surfaces than the other methods. Our results are also in accordance with their results in terms of the high cleansability of the rotary metal instrument. In addition, the cotton pellet showed moderate cleansability among the tested methods, but the cleansing time for the cotton pellet (60 s) was shorter than that of the titanium brush with (120 s + 60 s)/without (120 s) photodynamic therapy. If adjusting the difference of cleansing time, the cotton pellet might show equivalent cleansability to the titanium brush.

In contrast to the past in vivo and in vitro studies, the Er:YAG laser demonstrated an inferior cleansability on the contaminated implant surfaces. The Er:YAG setting (60 mJ/pulse, 10 pps) in the present study was within the normal recommended range for cleansing an implant surface without causing damage to the implant surface or the peri-implant tissue cells and to ensure the safety of peri-implant tissue. Kreisler et al. used the same setting to cleanse a contaminated implant surface but without water coolant and demonstrated a good result. The reason why we could not achieve the same result might be associated with the water coolant used for further safety reasons in our study. In the clinical setting, the Er:YAG laser has been applied to treat peri-implantitis. However, one report cautioned that the use of Er:YAG laser treatment as a non-surgical therapy had previously led to trauma of the peri-implant soft tissue, thereby causing unnecessary recession of the peri-implant mucosa. In this context, when the Er:YAG laser is applied to the treatment of peri-implant disease, water coolant should be considered for safety. There are many aspects that contribute to the efficacy of the Er:YAG laser (e.g., setting, coolant, tip distance from the tip to the contaminated implant surface). Such differences should be investigated in future studies.

Surface characteristics

Through SEM analysis and CFU counts, it was demonstrated that, except for the Er:YAG laser, decontamination of the machined surface implant was easier than that of the rough surface implant regardless of decontamination method. Gauze soaked in saline and the ultrasonic scaler demonstrated a statistically significant difference in CFU counts between the two surfaces. In this context, a machined surface implant may be advantageous for recovering biocompatibility after cleansing the contaminated implant surface. In a randomized controlled trial, Carcuac et al. [6] demonstrated greater treatment success in a machined surface implant group than a modified surface implant group. The present study may support this clinical result, and the application of gauze soaked in saline may be regarded as a gold standard technique to cleanse a machined surface implant.

Conclusions

In the present ex vivo experimental study, none of the tested decontamination methods thoroughly eliminated biofilms formed on rough/machined surface implants intraorally. Gauze soaked in saline and the rotary stainless steel instrument showed better cleansability than the ultrasonic scaler in qualitative and quantitative analyses and may be advantageous for cleansing contaminated implant surfaces. Additionally, except for the Er:YAG laser, each of the tested decontamination methods appeared to be more effective on machined surface implants than rough surface implants in terms of reducing biofilms qualitatively and quantitatively. Research on the optimum combination of different cleansing methods that compensate for each method’s respective downsides is urgently required. Further research is needed to elucidate the most effective method to cleanse contaminated implant surfaces.