To explore the effectiveness of glycine subgingival air polishing combined with guided tissue regeneration (GTR) in the treatment of peri-implantitis.

There were 28 peri-implantitis patients (34 implants) with alveolar bone resorption who were divided into 2 groups according to double blinded randomized controlled principles, and GTR was carried out respectively. In test group (n= 18) , the dental plaque on implant surface was cleaned by glycine subgingival air polishing. While in control group (n= 16) , plastic curettage instrument was used. The clinical parameters including plaque index, bleeding index, probing depth, clinical attachment level, and the vertical bone height were recorded and evaluated at baseline and 3, 6, and 12 months after treatment. All the clinical data was analyzed using the variance of repeated measurements, and independent samples t-test was applied at each time point. All the clinical parameters were compared with itself before and after treatment, and were compared between the two groups at baseline, 3 months, 6 months and 12 months after treatment. The difference was considered statistically significant by P<0.05.

There was no significant difference of the clinical parameters between the two groups at baseline (P>0.05) . After treatment, all subjects showed significant improvement in plaque index, bleeding index, probing depth, and clinical attachment level (P<0.05) . At 3 months, bleeding index was 1.61 ± 0.50 versus 2.13 ± 0.81 (t= 5.103, P= 0.031) , plaque index was 1.89 ± 0.58 versus 2.38 ± 0.62 (t= 5.556, P= 0.025) , probing depth was 4.06 ± 0.80 versus 4.69±0.95 (t= 4.440, P= 0.043) , and clinical attachment level was 3.72±1.07 versus 4.50 ± 0.97 (t= 4.879, P= 0.034) , respectively for test and control group. The difference between the two groups was statistically significant (P<0.05) . At 6 months, probing depth for test and control group was 3.28 ± 0.67 versus 3.88±0.8 (t= 4.994, P= 0.033) , and clinical attachment level was 3.28 ± 0.96 versus 4.06 ± 1.12 (t= 4.831, P= 0.035) . The difference between the two groups was statistically significant (P<0.05) . At 12 months, probing depth for test and control group was 3.00 ± 0.69 versus 3.56 ± 0.89 (t= 4.302, P= 0.046) , and clinical attachment level was 3.00 ± 0.77 versus 3.50 ± 0.63 (t= 4.325, P= 0.048) . The difference between the two groups was statistically significant (P<0.05) . While at 6 and 12 months, both groups presented improvement in plaque index and bleeding index, however, inter-group difference was not significant (P>0.05) . The vertical bone height for test and control group was 3.44±0.70 versus 2.88±0.81 (t= 4.831, P= 0.035) at 3 months, 3.50 ± 0.79 versus 2.94 ± 0.77 (t= 4.412, P= 0.044) at 6 months, and 3.56 ± 0.78 versus 3.00 ± 0.63 (t= 5.087, P= 0.031) at 12 months, and the increment in test group was more remarkable (P<0.05) .

Glycine subgingival air polishing combined with GTR is more effective than mechanical curettage combined with GTR in controlling the clinical symptoms and improving bone regeneration in patients with peri-implantitis. Therefore, glycine subgingival air polishing is a better additional method when treating peri-implantitis with GTR.