Stability of alveolar ridge following horizontal guided bone regeneration after implant loading for 1 -2 years: a retrospective comparative study.

Abstract

Objective: This retrospective comparative study aimed to evaluate the effects of guided bone regeneration(GBR) on horizontal bone augmentation of the alveolar ridge in the mandibular posterior region and bone stability after loading for 1-2 years. We measured and analyzed the changes in alveolar ridge bone width to observe the clinical effect of bone grafting. The RANK/RANKL/OPG concentration in gingival crevicular fluid around the implant was quantitatively analyzed and compared with that of healthy natural teeth to assess the bone condition.

Methods: Fifty-two patients admitted to the Department of Implantology of Dalian Stomatological Hospital were selected. 22 implanted dentures of 22 patients that were repaired with soft tissue-level implants after horizontal bone grafting (experimental group). Thirty patients had 30 implanted dentures with the same system of implants without bone grafting (control group). The gingival crevicular fluid around the implant and healthy control natural teeth were collected via the same filter paper strip after loading for 1-2 years. The concentrations and ratios of RANKL and OPG were quantitatively detected via ELISA. The CBCT images taken before bone grafting, on the day after surgery, 6 months after surgery, and after loading were superimposed to measure the horizontal width of the alveolar ridge. Measurements were taken 2 mm apical from the top of the crest at the center of the implant.

Results: The average alveolar crest width in the experimental group was 3.72 ± 0.94 mm before surgery, 11.57 ± 1.44 mm on the day after surgery, 8.86 ± 1.37 mm at 6 months after surgery, and 7.62 ± 1.08 mm after 1-2 years of loading. The level of OPG in the experimental group was greater than that in the control group, and greater than that in the natural teeth; however, this difference was not significant (P > 0.05). The RANKL concentration in the gingival crevicular fluid of the two groups was similar, and the RANKL/OPG ratio of the implants in the experimental group was slightly lower than that in the control group; whereas the RANKL and ratio of the two groups were lower than that of the natural teeth (P > 0.05).

Conclusion: GBR application in the horizontal bone augmentation of the mandibular posterior dental region has positive clinical outcomes. After 1-2 years of implant loading, the bone in the neck of the implant in the experimental group is slightly more active than in the control group, and may still be in the process of osteogenesis.