Is It Safe to Reuse Healing Abutments? An Experimental Study on IL-1ß and TNF-α Cytokine Levels in Peri-Implant Crevicular Fluid.

PURPOSE: To compare pro-inflammatory cytokine levels in the peri-implant crevicular fluid (PICF) in unused and reused healing abutments. MATERIALS AND METHODS: This study was a controlled randomized, double-blind clinical trial. Seventy-two patients who met the inclusion criteria were divided into two groups. After one-stage implant placement, in group A, an unused healing abutment, and in group B, a reused healing abutment, was connected to the implant fixture. After 2 months, clinical measurements for keratinized gingiva (KG), plaque index (PI), and bleeding index (BI) (Ainamo and Bay) were taken, and PICF sampling was performed to evaluate pro-inflammatory IL-1ß and TNF-α cytokine levels using the ELISA test. Comparison of clinical measurements and cytokine levels between the two study groups was made using the Mann-Whitney test. RESULT: Clinical measurements and sampling were performed on 60 patients (nA = 27, nB = 33). There was no significant difference between the two groups in clinical measurements (BI (p = 0.96) and PI (p = 0.06)) or TNF-α (p = 0.63), and IL-1ß (p = 0.26) cytokine levels. CONCLUSION: Reused healing abutments that are cleaned and sterilized properly do not appear to induce further peri-implant pro-inflammatory response; therefore, they can be utilized temporarily until implant abutment insertion.

The Impact of Calcium Hydroxide on the Osteoinductive Capacity of Demineralized Freeze-Dried Bone Allograft: an In-Vitro Study.

STATEMENT OF THE PROBLEM: A great challenge in periodontal therapy is the regeneration enhancement of osseous defects through applying osteoinductive materials. Demineralized freeze-dried bone allograft (DFDBA) has already been introduced as an allograft with osteoconductive and variable osteoinductive properties. Calcium hydroxide [Ca(OH)2] is an available well-known material in dentistry, which induces hard tissue formation. PURPOSE: This study evaluated the efficiency of combination of DFDBA and Ca(OH)2 in improving the quality of osteoinduction of DFDBA. MATERIALS AND METHOD: Human bone marrow-derived mesenchymal stem cells were taken from volunteers' iliac crest. Cell proliferation was determined by MTT test at 18, 24 and 48 hours post-culture in 10 groups. The employed material were 0.5, 1.0 mg/ml Ca(OH)2 in two forms of suspension and pH-adjusted solution, 10mg/ml DFDBA per se and in combination with 0.5 and 1.0 mg/ml Ca(OH)2. Mineralization was assessed by Alizarin red staining in 10 mg/ml DFDBA, DFDBA+ 0.5 and 1 mg/ml Ca(OH)2 in solution and suspension forms. The data were statistically analyzed by using one-way ANOVA and Tukey's post-hoc test (p< 0.05). RESULTS: The pH-adjusted solutions exhibited better cell proliferation compared with the suspension groups. The combination of 0.5mg/ml Ca(OH)2 solution and DFDBA increased the cell proliferation and mineralization compared with DFDBA per se (p= 0.033). CONCLUSION: The combination of Ca(OH)2 with DFDBA improved the osteoinductivity of DFDBA.