Periodontal disease, as a prevalent public health problem, could leads to bone resorption and ultimate tooth loss. Due to the nature of interfacial hard to soft tissue structure in periodontal complex, its wound healing is more complicated than normal oral mucosa after surgical procedures. To improve the success rate of surgical regenerative therapies in periodontal tissue, having insight to the natural tissue dissimilarities and biomechanical concepts in periodontium is crucial. Optimal periodontal regeneration contains restoration of the all three components of periodontal ligament, cementum and alveolar bone. In recent decades, many researchers have developed and characterized several strategies according to interfacial tissue engineering for periodontal regeneration. In the current review, the bio-clinical principles and current strategies for periodontal regeneration and future perspective are discussed. . .

Background and objectives: The roots of the plants are used as a kind of materials in the slopes preservation and resistance. Because in addition to helping to preserving and resisting the environment, it has recovery ability and has no harmful and negative effects on the environment and has no additional costs too. Plant cover is caused for pastiness between soil particles for having root system and has significant impact in slope stabilization, for this reason, the biological characteristics of different species has great importance. The quantity of reinforcement depends on root biotechnical characteristics such as root density and tensile strength. In this study assessed these biotechnical properties. Materials and methods: In this study, two non-native afforested stands of pine (Pinus Sylvesteres) and acacia (Robinia Peseudo acasia) and two natural stands with native species of hornbeam (Carpinus Betulus) and summer alder (Alnus Subcordata) with similar habitat conditions (altitude, Slope and direction of slope, soil type, geology, etc) in the forest of Neka city (Neka-Zalmarud forestry plan) was and Six trees of each species were randomly selected for later analysis. The Root Area Ratio and tensile strength were investigated. Profile trenching method was used to analyze and compare their root distribution. The walls of the profile are divided into 10 cm horizons. Number and diameter of protruded roots in each depth were measured. Finally, the percentage of Root Area Ratio in each horizon was calculated. Standard Santam was used to determine the tensile strength of roots. Root samples were collected at the bottom (30% slope) of trees. Results: The results indicated that the Root Area Ratio were decreased with increasing depth According to the exponential function. The Root area ratio in non-native species is higher than native species. Which has obtained for Carpinus Betulus, Alnus Subcordata, Robinia Peseudo acasia and Pinus Sylvesteres, 0. 033± 0. 002, 0. 081± 0. 002, 0. 026± 0. 018± 0. 177± 0. 015 percent respectively. The diameter range of the tested roots was 2-9 mm. The results of tensile strength tests showed that with increasing diameter, the amount of tensile strength according to the According to the exponential function decreased. There is a positive power relationship between root diameter and tensile force. Conclusion: In this research tensile strength of native species is more than non-native one that has obtained for Carpinus Betulus, Alnus Subcordata, Robinia Peseudo acasia and Pinus Sylvesteres, 31. 93± 10. 3, 17. 57± 6. 98, 18. 4± 2. 41, 9. 77± 5. 46 Mpa respectively. The results of this work may help us when applying an efficient Bioengineering technique

The aim of this work was to assess the characteristics of Poplar root system. Root Area Ratio (RAR) values were obtained using profile trenching method. First a starting point along the row of trees was randomly selected. Then a ten meters contiguous profile was dug along the row of trees and roots on both trenches (At a distance of 0.5 and 1.0 meter from the trunks) were measured. RAR values of roots were obtained at depth increments of 0.1 m. Also 30 root specimens were analyzed for tensile strength. The results indicated that RAR declined mostly in depth and distance from the stems. This decrease approximated a power function. In most cases the maximum RAR values are located within the first layers, with maximum rooting depth at about 1.0 m. The minimum and maximum RAR values along the profiles were 0.004% and 0.534% for nearer and 0.001% and 0.314% for farther trenches to stem respectively. The results of traction tests revealed that a positive power function existed between tensile force and root diameter. The mean root tensile strength and diameter were 19.92±4.12 MPa and 1.51±0.95 mm respectively. The root tensile strength values showed that root strength decreases with diameter following a power law equation. The data presented in this study expand the knowledge on most important biotechnical properties of Poplar growing in Iran.

The soil Bioengineering is an applied science that it is the composition of structural, biological and environment concepts for soil erosion, Sediment and flood control. Biotechnical engineering techniques rely on biological knowledge to build geotechnical and hydraulic structures and to secure unstable slopes and banks. The largest enhancement in development of new soil Bioengineering methods happened in European and 1900s. The recorded document showed that the first documented experiences, including reports and publications, were produced in the areas of the Alps, Austria, Germany, and Switzerland. Soil Bioengineering is the living plant materials that this use in engineering structures and apply sites treatment with problems including surface soil stability and soil erosion. In this study, some methods of soil Bioengineering presented in water management such as Live Pole Drains, Live Silt Fences, Brush Layering, Live Fascine, Live Stake and etc. and Steep slope stabilization such as Wattle Fences, Modified Brush Layers, Brush Layers in a Cut, Live Cribwall. Techniques such as wattle fences and modified brush layers can use for unstable slope or reducing slope angle and also help in vegetation establishment.