Changes in Hard and Soft Tissue During the First 6 Months After Immediate Implant Placement and Provisionalization of a Single Anterior Maxillary Incisor: A Prospective Cohort Study

Background: To evaluate changes in hard and soft tissue during the first 6 months after immediate implant placement and provisionalization (IIPP) of a single maxillary incisor.Methods: Failed maxillary incisors were replaced with IIP implants in 34 patients. Intraoral scans and cone beam computed tomography (CBCT) were performed before and 6 months after IIPP. Changes in soft tissue thickness, soft tissue contour, and hard tissue contour were measured by a three-dimensional superimposition method. The correlations of hard and soft tissue contour changes were assessed.Results: A total of 31 patients completed the study. Soft tissue contour tended to collapse after 6 months. Soft tissue was significantly thickened 1–3 mm below the gingival margin. Correlation analysis showed strong correlations between the hard and soft tissue contour changes at 0–5 mm apical to the implant platform. The mid-facial recession at 6 months was −0.46 ± 0.55 mm.Conclusions: Soft tissue contour collapsed after tooth extraction, regardless of IIPP. Both soft and hard tissue change affected the soft tissue contour change.

A Novel Zero Watermarking Based on DT-CWT and Quaternion for HDR Image

This paper presents a high dynamic range (HDR) image zero watermarking method based on dual tree complex wavelet transform (DT-CWT) and quaternion. In order to be against tone mapping (TM), DT-CWT is used to transform the three RGB color channels of the HDR image for obtaining the low-pass sub-bands, respectively, since DT-CWT can extract the contour of the HDR image and the contour change of the HDR image is small after TM. The HDR image provides a wide dynamic range, and thus, three-color channel correlations are higher than inner-relationships and the quaternion is used to consider three color channels as a whole to be transformed. Quaternion fast Fourier transform (QFFT) and quaternion singular value decomposition (QSVD) are utilized to decompose the HDR image for obtaining robust features, which is fused with a binary watermark to generate a zero watermark for copyright protection. Furthermore, the binary watermark is scrambled for the security by using the Arnold transform. Experimental results denote that the proposed zero-watermarking method is robust to TM and other image processing attacks, and can protect the HDR image efficiently.

Subaerial beach morphology change from multiple storms during the 2020 hurricane season

Frequent or consecutive storms impacting coastal areas can result in unexpected or variable impacts. This study evaluates spatiotemporal variability and cumulative impacts on the subaerial beach from four major tropical storms of varying intensity and proximity impacting the study area of Palm Beach County, Florida, during the 2020 Atlantic Basin Hurricane season. Impacts from Hurricanes Isaias, Laura, Sally, and Teddy were measured using Real-Time Kinematic Global Positioning System (RTK GPS) at 14 transects throughout the northern and southern portion of the county. Alongshore morphologic variability resulted from each storm, with some expected patterns of erosion and accretion with a few unexpected impacts. The first three storms caused swash or collision regime impacts on the Sallenger scale. Hurricane Teddy was the fourth storm to impact the study area, causing overwash at numerous locations. Whereas the first two storms of the season caused mostly erosion of the subaerial beach, the southeasterly approach of Hurricane Sally reversed the cumulative volume loss trend in the northern portion of the study area with accretion. Hurricane Teddy was the most distant storm but occurred at the highest tide and produced the largest waves and highest winds. The most variable patterns in erosion and accretion resulted from Hurricane Teddy, which also dominated the overall (or cumulative) volume and contour change. Further study is recommended for a multi-storm season that includes the subaqueous portion of the beach profile to elucidate trends of cross-shore and alongshore drivers of storm-induced morphology change.