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BACKGROUND: This study evaluates the long-term stability and clinical outcomes of the reverse palatal pedicle graft (RPPG) technique in treating maxillary molar palatal recessions over a 3 to 4-year follow-up period. METHODS: Three patients with palatal recession defects on maxillary molars were treated using the RPPG technique. Clinical parameters including recession depth, probing depth, and clinical attachment levels (CALs) were recorded at baseline, 2 months, and 3-4 years postoperatively. Healing outcomes, tissue perfusion, and soft tissue thickness were assessed through clinical examination, cone beam computed tomography (CBCT), and ultrasonography. RESULTS: All patients demonstrated significant CAL gain and partial root coverage. The RPPG technique resulted in significant improvements in attachment gain (41%-67%) and root coverage (44%-83%). In addition, a CBCT scan of one grafted site at a 4-year follow-up (Case 1) demonstrates a gain in soft tissue thickness and partial root coverage. Ultrasound imaging of another grafted site at a 4-year follow-up (Case 2) demonstrates a gain in soft tissue thickness and adequate graft perfusion. The outcomes suggest stable graft sites with some evidence of creeping attachment. CONCLUSION: The RPPG technique provides a viable option for treating maxillary molar palatal recessions, demonstrating promising long-term stability and clinical improvements. Further studies with larger sample sizes and frequent follow-ups are needed to better understand the dynamics of creeping attachment and refine clinical guidelines for palatal grafting. KEY POINTS: The reverse palatal pedicle graft (RPPG) is a surgical technique providing a viable solution for the treatment of maxillary molar palatal root coverage for a single recession site with 3-4 years of follow-up demonstrating a degree of predictability. Clinical indications for the application of the RPPG technique include severe palatal recession with little to no interproximal attachment loss (RT1 or RT2), palatal root sensitivity, and a sufficient amount of keratinized tissue on the palatal aspect of adjacent teeth. The main limitations of the application of the RPPG technique include its ability to treat only one isolated recession site, the inability for coronal advancement of the flap, and the quality and thickness of the autogenous graft being patient-dependent. PLAIN LANGUAGE SUMMARY: This study explores the reverse palatal pedicle graft (RPPG) technique, a method used to treat gum recession in the palate around the upper posterior teeth. The research followed three patients over a period of 3-4 years after they underwent the RPPG procedure. This technique involves using a piece of tissue from the roof of the mouth and repositioning it to cover the receded gum area. All patients showed significant improvement in gum attachment and coverage of the exposed roots. The grafts remained stable, and there was continued growth of the gum tissue, further covering the exposed roots over time. These promising results suggest that RPPG could be a reliable and effective option for treating severe gum recession on the roof of the mouth. However, further studies with larger patient groups are needed to confirm these findings and refine the technique.

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AIM: The aim of this study is to assess early wound healing expression of local angiogenic biomarkers following connective tissue graft (CTG) at dental implant sites. METHODS: Twenty-eight subjects with single dental implants exhibiting a soft tissue dehiscence were included and randomly treated with CTG, either with coronally advanced flap (CAF) or with tunnel technique (TUN). Peri-implant crevicular fluid (PICF) was collected at the midfacial and midlingual aspect of the implant sites at baseline and at 3, 7, 14, 30, and 90 days after the surgical intervention. The expression of angiogenin (ANG), fibroblast growth factor-2 (FGF-2), platelet-derived growth factor (PDGF), tissue inhibitor of metalloproteinases-2 (TIMP-2), and vascular endothelial growth factor (VEGF) was investigated over a period of 3 months. Patient-reported outcomes, clinical measurements, and ultrasonography scans at multiple time points were also evaluated. RESULTS: The longitudinal regression revealed a significant difference in the expression of VEGF and TIMP-2 between CAF- and TUN-treated sites over 3 months (p = .033 and p = .004, respectively), whereas no significant differences were observed for ANG, FGF-2 and PDGF between the two groups. At 7 days, a direct correlation was observed between ANG levels and ultrasonographic color velocity in the CAF group (p < .001) and between ANG levels and ultrasonographic color power in the TUN group (p = .028). VEGF levels and ultrasonographic mean perfused area of the CTG were significantly correlated at the 7-day time point (p < .001 for both CAF and TUN). The expression of VEGF at 7 days was directly associated with mucosal thickness gain at 1 year (p < .001 for both groups). Early TIMP-2 expression showed an inverse correlation with time to recovery (p = .002). TIMP-2 levels at 3 months exhibited inverse correlations with mean dehiscence coverage (p = .004) and the rate of complete dehiscence coverage (p = .012). CONCLUSION: PICF biomarkers can be used to monitor early wound healing events following soft tissue grafting at implant sites. VEGF and TIMP-2 showed correlations with the 1-year clinical and volumetric outcomes, as well as with post-operative patient-reported outcomes and Doppler Ultrasonographic tissue perfusion-related parameters.

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AIMS: The aim of this experimental in vivo pilot study was to evaluate the effect of the local delivery of pamidronate within a collagen membrane on the changes in the buccal soft and hard tissue dimensions at the time of immediate implant placement and whether this effect was influenced by the placement of bone substitutes. METHODS: In six beagle dogs, the distal roots of the third and fourth premolars were extracted, and immediate implants were placed. Treatment groups were randomly allocated to each socket: (i) covering the buccal bone with pamidronate-soaked collagen membrane (BP group), (ii) filling the gap defect with synthetic bone substitute (BS group), (iii) filling the gap defect with synthetic bone substitute and covering the buccal bone with pamidronate soaked collagen membrane (BP/BS group), (iv) no treatment (control group). Intraoral scanning was performed immediately after the surgery and at 20 weeks. Histomorphometric and micro-computed tomography (CT) outcomes were evaluated at 20 weeks. RESULTS: The micro CT analysis demonstrated that the BP group showed no apparent difference in vertical bone level with residual mesial root area, while control group showed significant buccal bone resorption at the implant site. The histomorphometric analysis demonstrated that the vertical bone level of buccal plate was significantly differed between the BP and control group (0.34 ± 0.93 and 1.27 ± 0.56 mm, respectively; p = .041). There was no statistically significant difference in the horizontal ridge width (HRW 1, 2, 3) among the groups. Also, the thickness, height and buccal contours of the soft tissue did not reveal significant changes among the groups. CONCLUSION: The local delivery of pamidronate to the outer surface of the buccal wall at the time of immediate implant placement effectively limits buccal bone resorption. The results from the present investigation should be interpreted with caution, as well as its clinical translatability. Further investigation is needed to understand the pamidronate binding and releasing kinetic, as well as the ideal carrier of this drug for its topical application.

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Microbiome dysbiosis has largely been defined using compositional analysis of metagenomic sequencing data; however, differences in the spatial arrangement of bacteria between healthy and diseased microbiomes remain largely unexplored. In this study, we measured the spatial arrangement of bacteria in dental implant biofilms from patients with healthy implants, peri-implant mucositis, or peri-implantitis, an oral microbiome-associated inflammatory disease. We discovered that peri-implant biofilms from patients with mild forms of the disease were characterized by large single-genus patches of bacteria, while biofilms from healthy sites were more complex, mixed structures. Based on these findings, we propose a model of peri-implant dysbiosis where changes in biofilm spatial architecture allow the colonization of new community members. This model indicates that spatial structure could be used as a potential biomarker for community stability and has implications in diagnosis and treatment of peri-implant diseases. These results enhance our understanding of peri-implant disease pathogenesis and may be broadly relevant for spatially structured microbiomes.

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The exchange of mobile genetic elements (MGEs) facilitates the spread of functional traits including antimicrobial resistance within bacterial communities. Tools to spatially map MGEs and identify their bacterial hosts in complex microbial communities are currently lacking, limiting our understanding of this process. Here we combined single-molecule DNA fluorescence in situ hybridization (FISH) with multiplexed ribosomal RNA-FISH to enable simultaneous visualization of both MGEs and bacterial taxa. We spatially mapped bacteriophage and antimicrobial resistance (AMR) plasmids and identified their host taxa in human oral biofilms. This revealed distinct clusters of AMR plasmids and prophage, coinciding with densely packed regions of host bacteria. Our data suggest spatial heterogeneity in bacterial taxa results in heterogeneous MGE distribution within the community, with MGE clusters resulting from horizontal gene transfer hotspots or expansion of MGE-carrying strains. Our approach can help advance the study of AMR and phage ecology in biofilms.

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Despite the various treatments proposed with barrier membranes, one of the main challenges for guided bone regeneration (GBR) is maintaining space for large defects and ensuring an adequate blood supply. The presented feasibility case series aims to introduce an original titanium frame (TF) design, customized for each defect, as a modification of well-known principles and materials for GBR to achieve an enhanced and more predictable horizontal and vertical bone augmentation. Three patients with significant horizontal defects were treated with pre-trimmed TFs to create needed space, and then a 50/50 mixture of autograft and bovine xenograft was placed and covered with a collagen membrane. After 8 months of healing, the sites were reopened, and the titanium screws were removed with the frame. An average of 8.0 ± 1.0 mm of horizontal and 3.0 ± 0.0 mm of vertical bone gain were achieved at the time of reentry and implant placement surgery. Bone core biopsy sample was obtained during the implant placement. Histomorphometric analysis revealed that 42.8% of the sample was new vital bone, 18.8% was residual bone graft particles, and 38.4% was bone marrow-like structures. After 3 to 4 months from implant placement, the implants were restored with provisional crowns and then finalized with zirconia screw-retained crowns. This case series suggests that GBR utilizing TFs with or without collagen membranes can be considered a suitable approach for horizontal and vertical bone augmentation. However, based on only three reported cases, the results should be carefully interpreted.

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Despite the various barrier membranes proposed, one of the main challenges for guided bone regeneration (GBR) is space maintenance for large defects as well as ensure adequate blood supply. The presented feasibility case series aims to introduce an original titanium frame (TF) design, customized for each defect, as a modification of well-known principles and materials for GBR, for an enhanced and more predictable horizontal and vertical bone augmentation. Three patients with significant horizontal defects were treated with pre-trimmed TFs to create needed space, a 50%-50% mixture of autograft and bovine xenograft was placed, and then covered with collagen membrane. After 8 months of healing, the sites were reopened, the titanium screws were removed with the frame. An average of 8.0 ± 1.0mm horizontal and 3.0 ± 0.0mm vertical bone gain was achieved at the time of re-entry and implant placement surgery. Bone core biopsy was obtained during the implant placement. Histomorphometric analysis revealed that 42.8% of the sample was new vital bone, 18.8% was residual bone graft particles, and 38.4% was bone marrow like structures. After 3-4 months from implant placement, the implants were restored with provisional crowns and then finalized with zirconia screw-retained crowns. This case series suggests that GBR utilizing TFs with or without collagen membranes can be considered a suitable approach for horizontal and vertical bone augmentation. However, based on only three reported cases, the result should be carefully interpreted.

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Partial extraction therapy (PET) is a set of surgical techniques that preserve a portion of the patient's own root structure to maintain blood supply derived from the periodontal ligament complex in order to maintain the periodontium and peri-implant tissues during restorative and implant therapy. PET includes the socket shield technique (SST), proximal shield technique (PrST), pontic shield technique (PtST), and root submergence technique (RST). In a traditional hybrid technique, total extraction and full-arch dental implant therapy often require significant bone reduction and palatal/lingual implant placement. In addition, postextraction preservation of the ridge architecture is a major challenge. This case series demonstrates the use of a combination of PET techniques with digital implant planning and guided implant surgery to achieve highly esthetic outcomes in full-arch implant therapy.

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Partial extraction therapy (PET) is a group of surgical techniques that preserve the periodontium and peri-implant tissues during restorative and implant therapy by conserving a portion of the patient's own root structure to maintain the blood supply, derived from the periodontal ligament complex. PET includes the socket shield technique (SST), proximal shield technique (PrST), pontic shield technique (PtST), and root submergence technique (RST). Although their clinical success and benefits have been demonstrated, several studies report possible complications. The focus of this article is to highlight management strategies for the most common complications associated with PET, including internal root fragment exposure, external root fragment exposure, and root fragment mobility.

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Multicellular spheroids made of stem cells can act as building blocks that fuse to capture complex aspects of native in vivo environments, but the effect of hydrogel viscoelasticity on cell migration from spheroids and their fusion remains largely unknown. Here, we investigated the effect of viscoelasticity on migration and fusion behavior of mesenchymal stem cell (MSC) spheroids using hydrogels with a similar elasticity but different stress relaxation profiles. Fast relaxing (FR) matrices were found to be significantly more permissive to cell migration and consequent fusion of MSC spheroids. Mechanistically, inhibition of ROCK and Rac1 pathways prevented cell migration. Moreover, the combination of biophysical and biochemical cues provided by fast relaxing hydrogels and platelet-derived growth factor (PDGF) supplementation, respectively, resulted in a synergistic enhancement of migration and fusion. Overall, these findings emphasize the important role of matrix viscoelasticity in tissue engineering and regenerative medicine strategies based on spheroids.

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Conventional approaches to full-arch implant dentistry require a verified master model created by luting together impression jigs. This process involves numerous steps and is sometimes prone to errors that require subsequent correction. A novel approach involving an extraoral scanning technique using an Imetric 4D Imaging system demonstrates an alternative for same-day delivery of printed full-arch prosthetics. Advantages include the ability to offer a same-day provisional restoration without needing to verify an analog master cast.

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AIM: The clinical case series presents a minimally invasive modified tunnel procedure with autogenous connective tissue graft (CTG) using a V-reverse sutures to treat multiple gingival recessions. BACKGROUND: In periodontal and peri-implant plastic procedures, proper graft and flap stabilization are crucial in the outcomes. The coronally advanced flap allows for better access with the possibility of suturing the graft to the de-epithelialized papillae of the periosteum; there is little evidence with using the V-reverse sutures technique in stabilizing the graft and the flap when performing tunnel techniques (TUN). The following case series presents a minimally invasive modified tunnel procedure with autogenous CTG using V-reverse sutures to treat gingival recessions. CASE DESCRIPTION: Three patients with Miller Class I maxillary buccal gingival recessions defects were selected for this study. All subjects were treated with the minimally invasive modified tunnel technique with autogenous subepithelial CTG. V-reverse sutures technique was performed to further improve the stability of the graft at the recipient site. Clinical parameters, including mean recession depth and root coverage esthetic score (RES), were recorded at baseline, 1 week, 2 weeks, 1 month, 3 months, 6 months, and 1-year postoperative follow-up visits. CONCLUSION: At the 1-year follow-up, complete root coverage was achieved in multiple gingival recessions defect sites. In conclusion, this technique represents an alternative treatment for Miller Class I gingival recessions defects with clinical and esthetically satisfactory outcomes. CLINICAL SIGNIFICANCE: Combining the advantages of V-reverse sutures and CTG in the treatment of gingival recessions is feasible and noninvasive.

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The extracellular matrix (ECM) mechanical properties regulate key cellular processes in tissue development and regeneration. The majority of scientific investigation has focused on ECM elasticity as the primary mechanical regulator of cell and tissue behavior. However, all living tissues are viscoelastic, exhibiting both solid- and liquid-like mechanical behavior. Despite increasing evidence regarding the role of ECM viscoelasticity in directing cellular behavior, this aspect is still largely overlooked in the design of biomaterials for tissue regeneration. Recently, with the emergence of various bottom-up material design strategies, new approaches can deliver unprecedented control over biomaterial properties at multiple length scales, thus enabling the design of viscoelastic biomaterials that mimic various aspects of the native tissue ECM microenvironment. This review describes key considerations for the design of viscoelastic biomaterials for tissue regeneration. We provide an overview of the role of matrix viscoelasticity in directing cell behavior toward regenerative outcomes, highlight recent strategies utilizing viscoelastic hydrogels for regenerative therapies, and outline remaining challenges, potential solutions, and emerging applications for viscoelastic biomaterials in tissue engineering and regenerative medicine. Impact statement All living tissues are viscoelastic. As we design viscoelastic biomaterials for tissue engineering and regenerative medicine, we must understand the effect of matrix viscoelasticity on in vitro cell behavior and in vivo regenerative outcomes. Engineering the next generation of biomaterials with tunable viscoelasticity to direct cell and tissue behavior will contribute to the development of in vitro tissue models and in vivo regenerative therapies to address unmet clinical needs.

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Partial extraction therapy (PET) is a collective concept encompassing a group of surgical techniques including socket shield, root membrane, proximal shield, pontic shield, and root submergence. PET uses the patient's own root structure to maintain blood supply derived from the periodontal ligament complex to preserve the periodontium and peri-implant tissues during restorative and implant therapy. This review aims to summarize the current knowledge regarding PET techniques and present a comprehensive evaluation of human clinical studies in the literature. Two independent reviewers conducted electronic and manual searches until January 1, 2021, in the following electronic bibliographic databases: PubMed, EMBASE, and Dentistry & Oral Sciences Source. Gray literature was searched to identify additional candidates for potential inclusion. Articles were screened by a group of 4 reviewers using the Covidence software and synthesized. A systematic search of the literature yielded 5714 results. Sixty-four articles were selected for full-text assessment, of which 42 eligible studies were included in the review. Twelve studies were added to the synthesis after a manual search of the reference lists. A total of 54 studies were examined in this review. In sum, PET techniques offer several clinical advantages: (1) preservation of buccal bone postextraction and limitation of alveolar ridge resorption, (2) mitigation of the need for invasive ridge augmentation procedures, and (3) soft-tissue dimensional stability and high esthetic outcomes. Further randomized clinical studies with larger sample sizes are needed to improve the understanding of the long-term clinical outcomes of PET.

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Dental, oral, and craniofacial (DOC) regenerative medicine aims to repair or regenerate DOC tissues including teeth, dental pulp, periodontal tissues, salivary gland, temporomandibular joint (TMJ), hard (bone, cartilage), and soft (muscle, nerve, skin) tissues of the craniofacial complex. Polymeric materials have a broad range of applications in biomedical engineering and regenerative medicine functioning as tissue engineering scaffolds, carriers for cell-based therapies, and biomedical devices for delivery of drugs and biologics. The focus of this review is to discuss the properties and clinical indications of polymeric scaffold materials and extracellular matrix technologies for DOC regenerative medicine. More specifically, this review outlines the key properties, advantages and drawbacks of natural polymers including alginate, cellulose, chitosan, silk, collagen, gelatin, fibrin, laminin, decellularized extracellular matrix, and hyaluronic acid, as well as synthetic polymers including polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), poly (ethylene glycol) (PEG), and Zwitterionic polymers. This review highlights key clinical applications of polymeric scaffolding materials to repair and/or regenerate various DOC tissues. Particularly, polymeric materials used in clinical procedures are discussed including alveolar ridge preservation, vertical and horizontal ridge augmentation, maxillary sinus augmentation, TMJ reconstruction, periodontal regeneration, periodontal/peri-implant plastic surgery, regenerative endodontics. In addition, polymeric scaffolds application in whole tooth and salivary gland regeneration are discussed.

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Additive manufacturing (AM) is the automated production of three-dimensional (3D) structures through successive layer-by-layer deposition of materials directed by computer-aided-design (CAD) software. While current clinical procedures that aim to reconstruct hard and soft tissue defects resulting from periodontal disease, congenital or acquired pathology, and maxillofacial trauma often utilize mass-produced biomaterials created for a variety of surgical indications, AM represents a paradigm shift in manufacturing at the individual patient level. Computer-aided systems employ algorithms to design customized, image-based scaffolds with high external shape complexity and spatial patterning of internal architecture guided by topology optimization. 3D bioprinting and surface modification techniques further enhance scaffold functionalization and osteogenic potential through the incorporation of viable cells, bioactive molecules, biomimetic materials and vectors for transgene expression within the layered architecture. These computational design features enable fabrication of tissue engineering constructs with highly tailored mechanical, structural, and biochemical properties for bone. This review examines key properties of scaffold design, bioresorbable bone scaffolds produced by AM processes, and clinical applications of these regenerative technologies. AM is transforming the field of personalized dental medicine and has great potential to improve regenerative outcomes in patient care.

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The role of urea as a kinetic promoter for the growth of CO2 hydrates is revealed for the first time using molecular dynamics simulations. Analysis of simulation trajectories shows that urea plays two important roles in the growth process: increasing mass transport of CO2 and catalyzing cage formation at the solid-liquid interface.

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Externally applied electric fields have previously been utilized to direct the assembly of colloidal particles confined at a surface into a large variety of colloidal oligomers and nonclose-packed honeycomb lattices (J. Am. Chem. Soc. 2013, 135, 7839-7842). The colloids under such confinement and fields are observed to spontaneously organize into bilayers near the electrode. To extend and better understand how particles can come together to form quasi-two-dimensional materials, we have performed Monte Carlo simulations and complementary experiments of colloids that are strongly confined between two electrodes under an applied alternating current electric field, controlling field strength and particle area fraction. Of particular importance, we control the fraction of particles in the upper vs lower plane, which we describe as asymmetric confinement, and which effectively modulates the coordination number of particles in each plane. We model the particle-particle interactions using a Stockmayer potential to capture the dipolar interactions induced by the electric field. Phase diagrams are then delineated as a function of the control parameters, and a theoretical model is developed in which the energies of several idealized lattices are calculated and compared. We find that the resulting theoretical phase diagrams agree well with simulation. We have not only reproduced the structures observed in experiments using parameters that are close to experimental conditions but also found several previously unobserved phases in the simulations, including a network of rectangular bands, zig zags, and a sigma lattice, which we were then able to confirm in experiment. We further propose a simple way to precisely control the number ratio of particles between different planes, that is, superimposing a direct current electric field with the alternating current electric field, which can be implemented conveniently in experiments. Our work demonstrates that a diverse collection of materials can be assembled from relatively simple ingredients, which can be analyzed effectively through comparison of simulation, theory, and experiment. Our model further explains possible pathways between different phases and provides a platform for examining phases that have yet to be observed in experiments.