The influence of platform switching on clinical, laboratory, and image-based measures: a prospective clinical study.

PURPOSE: This prospective study was conducted to compare the marginal bone level alterations, stability/mobility measurements, and volume of myeloperoxidase (MPO) and nitric oxide (NO) of peri-implant sulcus fluid (PISF) between platform-switched (PS) and standard platform (SP) implants inserted to mandibular premolar/molar regions with a single-stage protocol. MATERIALS AND METHODS: Thirty-two (16 PS and 16 SP) implants restorated with fixed prosthesis were included in the study. For both implant systems standard implant dimensions were used. Implant abutment connections and final restorations were made after 3 months of osseointegration. Standard parallel periapical radiographs were used to measure marginal bone loss in over time. Resonance frequency analysis (RFA) and mobility measuring (MM) device were used to determine implant stability/mobility. PISF samples were derived with paper strips and PISF MPO and nitrite level analysis were done spectrophotometrically. Peri-implant parameters were assessed by periodontal indices and all parameters were evaluated at baseline, 1, 3, 6, and 12 months follow-up. RESULTS: No healing problems were recorded for all implants at the end of the study period. At 12 months, mean bone loss measures were 0.84 and 0.76 mm, and mean implant stability quotient (ISQ) values were 74.04 and 76 for PS and SP implants, respectively. Mean MM values were found as -4.82 for PS and -6.26 for SP implants. There were no significant differences between implant types according to PISF volume and laboratory biochemical measures including MPO and NO, and clinical peri- implant indices at any time point. CONCLUSION: Platform switching seems not to affect the marginal bone level, clinical peri-implant parameters and MPO and NO metabolism around implants inserted to mandibular premolar/molar regions when using a single-stage protocol.

Analysis of superoxide dismutase activity levels in gingiva and gingival crevicular fluid in patients with chronic periodontitis and periodontally healthy controls.

OBJECTIVES: Superoxide dismutase (SOD) is an antioxidant enzyme that acts against superoxide, an oxygen radical, released in inflammatory pathways and causes connective tissue breakdown. In this study, SOD activities in gingiva and gingival crevicular fluid (GCF) from patients with chronic periodontitis (CP) and periodontally healthy controls were compared. MATERIAL AND METHODS: Twenty-six CP patients and 18 controls were studied. In patients, teeth with moderate-to-severe periodontal breakdown and > or =5 mm pockets that required full-thickness flap surgery in the right or left maxillary quadrant, and in controls, teeth scheduled for extraction for orthodontic reasons were studied. After the clinical measurements (probing depth, clinical attachment level, gingival index, gingival bleeding index, plaque index), GCF samples were collected. Tissue samples were harvested from the same teeth, during flap operation in patients and immediately after tooth extraction in controls. SOD activities were spectrophotometrically assayed. The results were statistically analysed. RESULTS: Gingival SOD activity was significantly higher in the CP group than in controls (p<0.05). No significant difference was found in GCF SOD activity between the groups (p>0.05). Correlations between gingival and GCF SOD activities were not statistically significant in CP and control groups (p>0.05). CONCLUSION: In CP, SOD activity seems to increase in gingiva, probably as a result of a higher need for SOD activity and protection in gingiva in CP than in periodontal health, while not significantly changing in GCF, suggesting a weak SOD activity in GCF in periodontal disease state. The weak correlation between gingival and GCF SOD activities suggests distinct actions of these SODs.