Objective. In root coverage treatment, periodontal regeneration in gingival recession-type defects is an important challenge for the periodontist. The aim of this study was to histometrically investigate the effect of combined use of basic fibroblast growth factor (FGF-2) and beta tricalcium phosphate (β-TCP) on root coverage in dogs. Materials and methods.Sixteen adult beagle dogs were used. Buccal gingival recession defects were surgically created bilaterally in the maxillary canines. The defects in each animal were randomly assigned to: 1) an FGF-2 alone (control) group or 2) FGF-2/β-TCP (experimental) group. At 2, 4 or 8 weeks following surgery, specimens were obtained and subjected to microscopic examination and histometric assessment.Results. Inhibition of epithelial downgrowth was observed in both groups. At week 2, in the newly formed connective tissue at the coronal portion, FGF-2/β-TCP group showed significantly greater numbers of proliferating cell nuclear antigen -positive cells than the FGF-2 group (55.8 ± 4.8 versus 12.0 ± 1.4, P < 0.01). In the FGF-2/β-TCP group, new attachment was observed at 8 weeks, and the extent of new bone and cementum formation was significantly greater in the FGF-2/β-TCP group than that in the FGF-2 alone group. In both groups, the dentin surface beneath the new cementum presented minor irregularities, but no replacement resorption was observed.Conclusions. FGF-2 used in combination with β-TCP enhances formation of new bone and cementum without significant root resorption in root coverage in this dog model. This combination warrants further investigation in periodontal regeneration in root 3 coverage treatment.

Objectives. To investigate the effect of basic fibroblast growth factor (FGF-2) on root resorption following delayed autotransplantation in dog.Study design. Mandibular second and third premolars of beagle dogs were extracted to create sites for autotransplantation. After two months, in the experimental sites, the first and fourth mandibular premolars were extracted and air-dried prior to autotransplantation with the application of recombinant FGF-2, while control sites received teeth without FGF-2. At 2, 4, or 8 weeks after surgery, the animals were sacrificed and specimens collected and processed for histological examination.Results. Autotransplantation with FGF-2 yielded formation of new periodontal ligament-like tissues with inserting collagen fibers, associated cementum and bone. The occurrence of replacement resorption in the FGF-2 treated group was significantly lower than that in the control group (P < .01). Conclusion.It was demonstrated that topical application of FGF-2 reduced the occurrence of ankylosis and root resorption following delayed autotransplantation in this experimental model.

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BackgroundBias flow (BF) is essential to maintain mean airway pressure (MAP) and to washout carbon dioxide (CO2) from the oscillator circuit during high-frequency oscillatory ventilation (HFOV). If the BF rate is inadequate, substantial CO2 rebreathing could occur and ventilation efficiency could worsen. With lower ventilation efficiency, the required stroke volume (SV) would increase in order to obtain the same alveolar ventilation with constant frequency. The aim of this study was to assess the effect of BF rate on ventilation efficiency during adult HFOV.MethodsThe R100 oscillator (Metran, Japan) was connected to an original lung model internally equipped with a simulated bronchial tree. The actual SV was measured with a flow sensor placed at the Y-piece. Carbon dioxide (CO2) was continuously insufflated into the lung model (CO2), and the partial pressure of CO2 (PCO2) in the lung model was monitored. Alveolar ventilation (A) was estimated as CO2 divided by the stabilized value of PCO2. A was evaluated by setting SV from 80 to 180 mL (10 mL increments, n = 5) at a frequency of 8 Hz, a MAP of 25 cmH2O, and a BF of 10, 20, 30, and 40 L/min (study 1). Ventilation efficiency was calculated as A divided by the actual minute volume. The experiment was also performed with an actual SV of 80, 100, and 120 mL and a BF from 10 to 60 L/min (10 L/min increments: study 2).ResultsStudy 1: With the same setting SV, the A with a BF of 20 L/min or more was significantly higher than that with a BF of 10 L/min. Study 2: With the same actual SV, the A and the ventilation efficiency with a BF of 30 L/min or more were significantly higher than those with a BF of 10 or 20 L/min.ConclusionsIncreasing BF up to 30 L/min or more improved ventilation efficiency in the R100 oscillator.Electronic supplementary materialThe online version of this article (10.1186/s40635-018-0176-3) contains supplementary material, which is available to authorized users.

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