Evaluation of Host β-Globin Gene Fragment Lengths in Peri-implant Crevicular Fluid During the Wound Healing Process: A Pilot Study

Purpose: To evaluate the host β-globin gene fragment lengths in the cell-free peri-implant crevicular fluid (PICF) during the wound healing process. Materials and Methods: Nineteen patients (25 implants) were recruited into this study. As part of the control group, gingival crevicular fluids (GCF) from healthy teeth were collected before implant placement. PICF specimens from each implant were collected during weeks 2 to 12 after implant placement. All GCF and PICF specimens were centrifuged to collect the supernatant as cell-free DNA. Five primer pairs specific to the β-globin gene for amplifying 110-base pair (bp), 325-bp, 408-bp, 536-bp, and 2-kilo-base pair (kb) amplicons were used to evaluate DNA fragment lengths with conventional polymerase chain reaction (PCR). The longest PCR amplicon of each specimen was recorded. Results: The number of 536-bp amplicons (10 of 25 implant specimens) and 2-kb amplicons (8 of 25 implant specimens) in week 2 was higher than at the other visits. In the study, the mucositis group showed the highest number of 536-bp amplicons (22 of 34 implant specimens) and 2-kb amplicons (12 of 34 implant specimens), whereas the healthy implant group showed a low number of 536-bp amplicons (3 of 66 implant specimens), and the cell-free PICF specimens had no 2-kb amplicons. Furthermore, 325-bp and 110-bp amplicons were similar in number in the control teeth and healthy implants. Conclusion: There was a difference in the number of the longest amplicons of cell-free PICF specimens between the mucositis and healthy implant groups. This pilot study suggests that the PCR amplicon lengths of β-globin gene fragments in cell-free PICF specimens might be used as a biomarker to monitor soft tissue inflammation around implants. Keywords: cell-free DNA, DNA fragment lengths, mucositis, peri-implant crevicular fluid