The effect of mini-implant design on peri-implantitis and pain level after insertion in orthodontic treatment: A prospective clinical study

Background. Orthodontic mini-implants provide skeletal anchorage for tooth movement. There are two designs of mini-implants, tapered and cylindrical, which exhibit different clinical characteristics, including possible micro-damage to cor-tical bone. Complications such as peri-implantitis and pain after mini-implant placement are common. The aim of this study was to evaluate the effect of mini-implant design on peri-implantitis and post-insertion pain level. Methods. A total of 152 tapered and cylindrical mini-implants were randomly inserted into 76 patients (17 male, 59 fe-male) who were over 16 years of age. Peri-implantitis was assessed using signs of inflammation around mini-implant head. Pain levels of injection, during and immediately after insertion up to one week after implantation, were registered using an 11-point horizontal visual analogue scale (VAS). Data were analyzed using chi-squared and Mann-Whitney U tests. Results. Peri-implantitis was observed in 7% of mini-implants. There was no significant difference between tapered and cylindrical mini-implants in the number of peri-implantitis cases (P > 0.05). Post-insertion pain increased for 6 hours after insertion, and then decreased gradually. None of the patients reported pain a week after mini-implant insertion. There was no significant difference in pain levels of the two groups at all time intervals (P > 0.05). Maximum post-insertion pain (6 hours after implantation: 2.52 ± 2.66) was significantly higher than injection pain (1.38±1.71) (P < 0.001). Conclusion. It was concluded that mini-implant design had no significant effect on peri-implantitis and post-insertion pain level. Key words: Mini-implant design, peri-implantitis, pain level, injection.