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Various biomaterial combinations have been studied focusing on their ability to stabilize blood clots and maintain space under soft tissue to support new bone formation. A popular combination is Deproteinized Bovine Bone Mineral (DBBM) placed with a native collagen membrane (NCM) tacked to native bone. In this study, we compared the outcome of this treatment option to those achieved with three different graft/membrane combinations with respect to total newly occupied area and the mineralized compound inside. After bi-lateral extraction of two mandibular premolars in five adult beagles L-shaped alveolar defects were created. A total of 20 defects healed for 6 weeks resulting in chronic type bone defects. At baseline, four options were randomly allocated to five defects each: a. DBBM + NCM with a four-pin fixation across the ridge; b. DBBM + RCLC (ribose cross-linked collagen membrane); c. DBBM + NPPM (native porcine pericardium membrane); and d. Ca-sulfate (CS) + RCLC membrane. Membranes in b/c/d were not fixed; complete tensionless wound closure was achieved by CAF. Termination after 3 months and sampling followed, and non-decalcified processing and toluidine blue staining were applied. Microscopic images obtained at standardized magnification were histomorphometrically assessed by ImageJ software (NIH). An ANOVA post hoc test was applied; histomorphometric data are presented in this paper as medians and interquartile ranges (IRs). All sites healed uneventfully, all sites were sampled and block separation followed before Technovit embedding. Two central sections per block for each group were included. Two of five specimen were lost due to processing error and were excluded from group b. New bone area was significantly greater for option b. compared to a. (p = 0.001), c. (p = 0.002), and d. (p = 0.046). Residual non-bone graft area was significantly less for option d. compared to a. (p = 0.026) or c. (p = 0.021). We conclude that collagen membranes with a prolonged resorption/barrier profile combined with bone substitutes featuring different degradation profiles sufficiently support new bone formation. Tacking strategy/membrane fixation appears redundant when using these biomaterials.

Additional file 1: Table S1. Eligibility criteria form. Table S2. Excluded reviews at the assessment of full-text and the main reasons for exclusion. Table S3. Characteristic of primary studies and overlap amongst systematic reviews of adjunctive antiseptic treatment. Table S4. Characteristic of primary studies and overlap amongst systematic reviews of adjunctive probiotic treatment. Table S5. Characteristic of primary studies and overlap amongst systematic reviews of adjunctive air-polishing treatment. Table S6. Characteristic of primary studies and overlap amongst systematic reviews of adjunctive laser and photodynamic treatment. Table S7. Characteristic of primary studies and overlap amongst systematic reviews of adjunctive local and systemic antibiotic treatment. Additional document 1. Data items of the systematic reviews and primary studies.

Firms often sell a transparent base product and a valuable add-on product. If only some consumers are aware of the latter, the add-on's effect on the base product's price will be ambiguous. Cross-subsidization between products to bait uninformed consumers might lower, intrinsic utility from the add-on for informed consumers might raise the price. We study this trade-off in the gasoline market by exploiting an alcohol sales prohibition at stations as an exogenous shifter of add-on availability. Gasoline margins drop by 5% during the prohibition. The effect is mediated by shop variety and local competition. Implications for gasoline market definition arise.

5th International MERGE Technologies Conference, IMTC, Chemnitz, Germany, 1 Dec 2021 - 2 Dec 2021; Technologies for lightweight structures : TLS 5(1), 51-60 (2021). doi:10.21935/tls.v5i1.162 special issue: "Special Issue: 5th International MERGE Technologies Conference (IMTC), 1st - 2nd December 2021, Chemnitz", Published by Technische Universität Chemnitz, Chemnitz