A review of 210Pb and 210Po in moss.

Among environment contaminants, 210Pb and 210Po have gained significant research attention due to their radioactive toxicity. Moss, with its exceptional adsorption capability for these radionuclides, serves as an indicator for environmental 210Pb and 210Po pollution. The paper reviews a total of 138 articles, summarizing the common methods and analytical results of 210Pb and 210Po research in moss. It elucidates the accumulation characteristics of 210Pb and 210Po in moss, discusses current research challenges, potential solutions, and future prospects in this field. Existing literature indicates limitations in common measurement techniques for 210Pb and 210Po in moss, characterized by high detection limits or lengthy sample processing. The concentration of 210Pb and 210Po within moss display substantial variations across different regions worldwide, ranging from

Influence of different implant designs on replacement of four teeth of the posterior free-end edentulism: Three-dimensional finite element analysis and clinic case validation.

BACKGROUND: With periodontal disease having an increasing incidence, mandibular free-end edentulism caused by periodontitis is clinically more common. Finite element analysis and clinical case reports were used to evaluate the influence of different designs on the load distribution of implant prosthesis in mandibular posterior free-end edentulism. METHOD: A finite element model of a mandible with posterior free-end edentulism was established. Considering the implant position and selection of single crown repair or splint repair, four designs were conducted including model A: 3435 × 37(four-unit fixed bridge supported by three implants, implant positions were 34, 35, 37); model B: 34,35 × 37, (34: a single implant crown) (35 ×37: three-unit fixed bridge supported by two implants, implant positions were 35, 37); model C: 34 × 3637(four-unit fixed bridge supported by three implants, implant positions were 34, 36, 37); and model D: 34 × 36, 37(37: a single implant crown)(34 ×36: three-unit fixed bridge supported by two implants, implant positions were 34, 36). Stress distribution and the Von Mises stress value of the implants, the crown and the bone around the implants were analyzed at vertical and 45° inclined load. RESULTS: Stress in the cortical bone was mainly concentrated around the implant neck, and maximum Von Mises stress (MVMS) of the four models was 11.6-16.1 MPa at vertical load and 61.74-96.49 MPa at 45° inclined load. Stress in the cancellous bone was concentrated around the implant base, and MVMS of four models was 3.075-3.899 MPa at vertical load and 5.021-6.165 MPa at 45° inclined load. Stress of the restoration crowns was mainly concentrated in the connector of the bridge, and MVMS of four models was 23.38-26.28 MPa at vertical load and 53.14-56.35 MPa at 45° inclined load. Stress of the implant interface was mainly concentrated on the surface of the smaller implants near the bridge, and MVMS of four models was 21.12-33.25 MPa at vertical load and 83.73-138.7 MPa at 45° inclined load. CONCLUSION: There was favorable stress distribution of the four models at vertical load and 45° inclined load. Design of a three-unit fixed bridge combined with a partial crown may be an available option for devising patient treatment plans with mandibular free-end edentulism.