In vivo evaluation of resorbable supercritical CO2 -treated collagen membranes for class III furcation-guided tissue regeneration.

The study evaluated the effects of a Supercritical CO2 (scCO2 ) on a commercially available decellularized/delipidized naturally derived porcine pericardium collagen membrane, Vitala®. The Vitala® and scCO2 treated experimental membranes were evaluated for guided tissue regeneration (GTR) of periodontal tissue in class III furcation defects utilizing a dog model. Physical material characterization was performed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The in vivo portion of the study was allocated to three-time points (6, 12, and 24-weeks) using standardized class III furcation defects created in the upper second and third premolars. The experimental defects (n = 5) were covered with either a collagen membrane (positive control), scCO2 -treated collagen membrane (experimental) or no membrane (negative control). Following sacrifice, histologic serial sections were performed from cervical to apical for morphologic/morphometric evaluation. Morphometric evaluation was carried out by ranking the presence of collagen membrane, amount of bone formation within the defect site and inflammatory cell infiltrate content. SEM showed the experimental scCO2 -treated membrane to have a similar gross fibrous appearance and chemical structure in comparison to the Vitala® Collagen membrane. A significant increase in membrane thickness was noted in the scCO2 -treated membranes (366 ± 54 µm) vs non-treated membranes (265 ± 75 µm). TGA and DSC spectra indicated no significant qualitative differences between the two membranes. For the in vivo results, both membranes indicated significantly greater amounts of newly formed bone (scCO2 : 2.85 ± 1.1; Vitala®: 2.80 ± 1.0) within the covered defects relative to uncovered controls (0.8 ± 0.27) at 24 weeks. Both membrane types gradually degraded as time elapsed in vivo from 6 to 12 weeks, and presented nearly complete resorption at 24 weeks. The inflammatory infiltrate at regions in proximity with the membranes was commensurate with healthy tissue levels from 6 weeks in vivo on, and periodontal ligament regeneration onset was detected at 12 weeks in vivo. The effect of the supplementary scCO2 treatment step on the collagen membrane was demonstrated to be biocompatible, allowing for the infiltration of cells and degradation over time. The treated membranes presented similar performance in GTR to non-treated samples in Class III furcation lesions. Defects treated without membranes failed to achieve regeneration of the native periodontium. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1320-1328, 2019.

Void and gap evaluation using microcomputed tomography of different fiber post cementation techniques.

STATEMENT OF PROBLEM: Few studies have investigated the voids and gaps produced during the cementation of fiber posts using different techniques. PURPOSE: The purpose of this study was to evaluate and quantify void and gap area formations of different fiber post cementation techniques using microcomputed tomography (µCT). MATERIAL AND METHODS: Standardized endodontically treated acrylic resin roots (N=24) were divided into 4 groups (n=6) according to different fiber posts cemented with the resin cement (FB); fiber posts relined with composite resin followed by cementation (FBR); fiber posts cemented using an ultrasonic device (FBU); and fiber posts relined with composite resin and cemented using an ultrasonic device (FBRU). Each specimen was scanned twice using micro-computed tomography (µCT; empty root, followed by after fiber post cementation). Digital imaging and communications in medicine (DICOM) files were transferred into 3-dimensional (3D) reconstruction software for analysis. Void volume in the cementation system and gap area formation were evaluated; quantitative and qualitative analyses were performed. The data were analyzed using 2-way ANOVA and the Tukey honest significant difference post hoc test (α=.05). RESULTS: FBR showed a lower percentage of voids than obtained for FB (P<.05). Groups FB, FBU, and FBRU did not show significant difference in void formation (P>.05). No significant differences were found in gap area formations among the experimental groups (P>.05). CONCLUSIONS: The use of a composite resin to reline the fiber post significantly decreased the void formation in the cementation procedure when no ultrasonic device was used. The use of an ultrasonic device did not decrease the percentage of void or gap formation for any technique evaluated.