Abstract
BACKGROUND: The plaque biofilm is a structurally diverse and compositionally complex aggregate, serving as the initiating factor of peri-implantitis and is closely related to the onset and progression of this disease (BMC Oral Health 24:105, 2024), (NPJ Biofilms Microbiomes 10:12, 2024). Previous studies have shown that compared to the microbial communities in healthy peri-implant tissues, the microbial communities beneath the mucosa in peri-implantitis are more complex and diverse, with a significant increase in periodontal pathogens. Due to the lack of cementum and periodontal ligament as a protective system, dental implants are more susceptible to bacterial infections than natural teeth. Therefore, the elimination of plaque biofilm is crucial in the treatment of peri-implantitis; the biofilm formed after implant debridement may affect the treatment outcome and the long-term stability of the implant. To explore these two issues, we conducted the following experiment. This experiment comparatively observed the microstructural changes on the surfaces of commonly used implant materials after traditional and laser treatments, evaluated their decontamination capabilities and antibacterial effects, thereby providing a theoretical basis for the use of lasers in the prevention and treatment of peri-implantitis. METHOD: The experiment is divided into 5 groups: normal group (A), carbon fiber scraping group (B), sandblasting group (C), Er: YAG laser group (E), and Nd: YAG laser group (N).Use a K-type thermocouple temperature measuring instrument to monitor the temperature changes on the material surface during processing; use a roughness measuring instrument to measure the surface roughness (Ra) of the material after processing. Plaque biofilm is formed on the surface of the material. After being treated in different ways, the decontamination ability is tested by scanning electron microscopy observation, live/dead bacterial staining combined with laser confocal imaging system observation and plate colony counting method. After using the above 5 methods to treat the specimen for 60 s, wear it in the mouth of the subject for 24 h, and observe the adhesion of live/dead bacteria with a laser confocal imaging system using live/dead bacterial staining. SPSS 27.0 software was used to perform statistical analysis on each group of data. RESULTS: 1. The heat generated by the four methods during the 60-second treatment process is all within the safe range ( P < 0.05). Carbon fiber scraping treatment has statistically significant changes in the surface roughness of the two materials ( P < 0.05). 2. After 48 hours of SEM observation, the surfaces of the two materials were almost completely covered by plaque biofilm, and the thickness of the plaques varied; the plaques in the three groups C, E, and N were scattered, and the bacterial cell membranes were incomplete, the bacterial cells were broken, and the bacteria were lost. Normal form. The plate colony count showed that the remaining bacterial content on the surface of the two materials in groups B, C, E, and N was much smaller than that in group A (P<0.05). Images obtained by laser confocal microscopy showed that the green fluorescence and red fluorescence of each group B, C, E, and N were significantly reduced, and the average fluorescence intensity was also reduced (P<0.05). 3. Laser scanning confocal microscope images show that each group has a large amount of green fluorescence covering most areas of the specimen surface uniformly or unevenly; the three treatments of C, E, and N can reduce the total average fluorescence intensity of groups Z and T, and The adhesion of dead bacteria on the surface increased (P<0.05). CONCLUSIONS: Er:YAG laser and water mist Nd:YAG laser will not have any adverse effects on the surface morphology, roughness and temperature changes of pure titanium and zirconia sheets. The laser is safer to use and can efficiently remove the material surface. Er:YAG laser and water mist Nd:YAG laser irradiation can increase the proportion of dead bacteria in reattached plaque.