Adaptive immunity of materials: Implications for tissue healing and regeneration

Recent cumulative findings signify the adaptive immunity of materials as a key agenda in tissue healing that can improve regenerative events and outcomes. Modulating immune responses, mainly the recruitment and functions of T and B cells and their further interplay with innate immune cells (e.g., dendritic cells, macrophages) can be orchestrated by materials. For instance, decellularized matrices have been shown to promote muscle healing by inducing T helper 2 (Th2) cell immunity, while synthetic biopolymers exhibit differential effects on B cell responses and fibrosis compared decellularized matrices. We discuss the recent findings on how implantable materials instruct the adaptive immune events and the subsequent tissue healing process. In particular, we dissect the materials’ physicochemical properties (shape, size, topology, degradation, rigidity, and matrix dynamic mechanics) to demonstrate the relations of these parameters with the adaptive immune responses in vitro and the underlying biological mechanisms. Furthermore, we present evidence of recent in vivo phenomena, including tissue healing, cancer progression, and fibrosis, wherein biomaterials potentially shape adaptive immune cell functions and in vivo outcomes. Our discussion will help understand the materials-regulated immunology events more deeply, and offer the design rationale of materials with tunable matrix properties for accelerated tissue repair and regeneration.

Erbium-doped yttrium aluminum garnet laser and advanced plateletrich fibrin+in periodontal diseases:Two case reports and review of the literature

BACKGROUND The goal of periodontal disease treatment is to completely remove bacteria and promote wound healing.The erbium-doped yttrium aluminum garnet(Er:YAG)laser is commonly used to treat periodontal disease.Advanced platelet-rich fibrin+(A-PRF+)secrets growth factors that accelerates soft-and hard-tissue regeneration and wound healing.Herein I present 2 cases of patients with oral diseases treated with a combination of Er:YAG laser and A-PRF+.CASE SUMMARY Case 1 was a female with pocket depth bone loss over 8 mm and infection of tooth 31 and 41,and severe advanced periodontitis with grade III mobility.Case 2 was a male with tooth 22 root end apical swelling and infection and alveolar bony defects.Clinical outcomes were recorded at 6 and 36 mo.In case 1,the Er:YAG laser was used to perform open flap debridement(100 mJ/pulse,15 Hz)and remove calculus and granulation tissue(50 mJ/pulse,30 Hz).In case 2 the laser was used to create a semilunar full thickness flap incision(80 mJ/pulse,20 Hz)and eliminate the pathogen(100 mJ/pulse,15 Hz).In both patients,A-PRF+mixed with bone was used to fill bone defects,and A-PRF+autologous membranes were used to cover tension-free primary flaps.There was no recurrent infection at 36 mo,and tissue regeneration and would healing occurred.CONCLUSION Debridement with an Er:YAG laser followed by treatment with A-PRF+is effective for the treatment periodontal diseases with bone defects.

Biodegradable magnesium barrier membrane used for guided bone regeneration in dental surgery

Barrier membranes are commonly used as part of the dental surgical technique guided bone regeneration(GBR)and are often made of resorbable collagen or non-resorbable materials such as PTFE.While collagen membranes do not provide sufficient mechanical protection of the covered bone defect,titanium reinforced membranes and non-resorbable membranes need to be removed in a second surgery.Thus,biodegradable GBR membranes made of pure magnesium might be an alternative.In this study a biodegradable pure magnesium(99.95%)membrane has been proven to have all of the necessary requirements for an optimal regenerative outcome from both a mechanical and biological perspective.After implantation,the magnesium membrane separates the regenerating bone from the overlying,faster proliferating soft tissue.During the initial healing period,the membrane maintained a barrier function and space provision,whilst retaining the positioning of the bone graft material within the defect space.As the magnesium metal corroded,it formed a salty corrosion layer and local gas cavities,both of which extended the functional lifespan of the membrane barrier capabilities.During the resorption of the magnesium metal and magnesium salts,it was observed that the membrane became surrounded and then replaced by new bone.After the membrane had completely resorbed,only healthy tissue remained.The in vivo performance study demonstrated that the magnesium membrane has a comparable healing response and tissue regeneration to that of a resorbable collagen membrane.Overall,the magnesium membrane demonstrated all of the ideal qualities for a barrier membrane used in GBR treatment.

Biodegradable magnesium fixation screw for barrier membranes used in guided bone regeneration

An ideal fixation system for guided bone(GBR)regeneration in oral surgery must fulfil several criteria that includes the provision of adequate mechanical fixation,complete resorption when no longer needed,complete replacement by bone,as well as be biocompatible and have a good clinical manageability.For the first time,a biodegradable magnesium fixation screw made of the magnesium alloy WZM211 with a MgF2 coating has been designed and tested to fulfill these criteria.Adequate mechanical fixation was shown for the magnesium fixation screw in several benchtop tests that directly compared the magnesium fixation screw with an equivalent polymeric resorbable device.Results demonstrated slightly superior mechanical properties of the magnesium device in comparison to the polymeric device even after 4 weeks of degradation.Biocompatibility of the magnesium fixation screw was demonstrated in several in vitro and in vivo tests.Degradation of the magnesium screw was investigated in in vitro and in vivo tests,where it was found that the screw is resorbed slowly and completely after 52 weeks,providing adequate fixation in the early critical healing phase.Overall,the magnesium fixation screw demonstrates all of the key properties required for an ideal fixation screw of membranes used in guided bone regeneration(GBR)surgeries.