Cell-Biomaterial constructs for wound healing and skin regeneration.

Over the years, conventional skin grafts, such as full-thickness, split-thickness, and pre-sterilized grafts from human or animal sources, have been at the forefront of skin wound care. However, these conventional grafts are associated with major challenges, including supply shortage, rejection by the immune system, and disease transmission following transplantation. Due to recent progress in nanotechnology and material sciences, advanced artificial skin grafts-based on the fundamental concepts of tissue engineering-are quickly evolving for wound healing and regeneration applications, mainly because they can be uniquely tailored to meet the requirements of specific injuries. Despite tremendous progress in tissue engineering, many challenges and uncertainties still face skin grafts in vivo, such as how to effectively coordinate the interaction between engineered biomaterials and the immune system to prevent graft rejection. Furthermore, in-depth studies on skin regeneration at the molecular level are still not fully understood; as a consequence, the development of novel biomaterial-based systems that interact with the skin at the core level has also been slow. This review will discuss (1) the biological aspects of wound healing and skin regeneration, (2) important characteristics and functions of biomaterials for skin regeneration applications, and (3) synthesis and applications of common biomaterials for skin regeneration. Finally, the current challenges and future directions of biomaterial-based skin regeneration will be addressed.

Evaluation of different materials used for sealing of implant abutment access channel and the peri-implant sulcus microbiota: A 6-month, randomized controlled trial.

OBJECTIVE: Peri-implantitis has been attributed to a myriad of factors, including microleakage at the abutment-implant interface. Implant abutment access channel sealing materials (IACSM) are readily used in implant dentistry, with little evidence on their effect on microleakage. This study aims to evaluate the effect of IACSM on the microbial composition in the implant access channel and the peri-implant sulcus. METHODS: A total of n = 8 patients (64 implants) were included in this single-blinded, randomized controlled trial, whereas four different materials (cotton, polytetrafluoroethylene [PTFE], synthetic foam, or polyvinyl siloxane [PVS]) were randomly placed as an IACSM. Following 6 months, microbial analysis was completed on the IACSM and samples from the peri-implant sulci via PCR and high-throughput sequencing. Bacterial samples on the IACSM and in the peri-implant sulci were classified according to Socransky's microbial complexes. RESULTS: There was a preponderance of early colonizing bacteria within the IACSM, while the peri-implant sulci were dominated by Orange complex bacteria. The proportion of Red and Orange complex members on the IACSM was significantly less than in the peri-implant sulci. The proportion of Green, Yellow, and Blue complex members found on the IACSM was significantly greater than in the peri-implant sulci. Atopobium, a diverse species not included in the microbial complexes, was frequently detected in the peri-implant sulcus samples. CONCLUSIONS: No detectable effects of IACSM on the microbial community in the peri-implant sulcus or on the IACSM were identified. Variation of bacterial species was most dependent on the individual patient. No significant differences were found in the periodontal parameters between the different treatment groups.

Bacteria take control of tolls and T cells to destruct jaw bone.

Bone undergoes a continuous cycle of remodeling for maintenance and healing. For almost a decade it has been appreciated that the immune system is intricately linked to bone homeostasis. Both acute and chronic inflammatory responses have been shown to impact bone health. A common form of inflammatory disease that causes bone destruction is the chronic infectious disease known as periodontitis (PD). PD is a bacteria-driven inflammation of the tooth-supporting apparatus that leads to resorption of the alveolar (jaw) bone, often leading to tooth loss. At the host-bacteria interface, Toll-like receptors (TLRs) play an instructive role in the development of innate and T cell adaptive responses to oral bacteria. Specifically, it is becoming apparent that TLR2-mediated inflammatory responses represent the major arm of the host immune response during periodontitis, and form an important link between periodontal infection and ensuing periodontal bone loss. This review summarizes the role of TLR2-mediated interplay between immune cells and bone cells in a periodontal disease setting.

TLR2 signaling and Th2 responses drive Tannerella forsythia-induced periodontal bone loss.

Periodontal disease (PD) is a chronic inflammation of the tooth-supporting soft tissue and alveolar bone due to infection by a select group of gram-negative microbes, which leads to tooth loss if untreated. Because mice deficient in CD4(+) cells are resistant to infection-induced alveolar bone loss, Th cells have been implicated in bone-destructive processes during PD. However, the extent to which different Th cell subtypes play roles in pathogenesis or host protection remains to be defined and is likely to vary depending on the dominant microorganism involved. By far, Porphyromonas gingivalis is the best-studied periodontal microbe in PD. Although the gram-negative anaerobe Tannerella forsythia is also a vital contributor to periodontal bone loss, almost nothing is known about immune responses to this organism. Previous studies from our laboratory revealed that T. forsythia induces periodontal bone loss in mice and that this bone loss depends on the bacterially expressed BspA protein. In this study, we showed that T. forsythia activates murine APCs primarily through TLR2-dependent signaling via BspA. Furthermore, T. forsythia infection causes a pronounced Th2 bias, evidenced by T cell expression of IL-5, but not IFN-γ or IL-17, in draining lymph nodes. Consistently, deficiencies in TLR2 or STAT6 result in resistance to T. forsythia-induced alveolar bone loss. Thus, TLR2 signaling and Th2 cells play pathogenic roles in T. forsythia-induced alveolar bone destruction.

Identification of a unique TLR2-interacting peptide motif in a microbial leucine-rich repeat protein.

Pathogenesis of many bacterially-induced inflammatory diseases is driven by Toll-like receptor (TLR) mediated immune responses following recognition of bacterial factors by different TLRs. Periodontitis is a chronic inflammation of the tooth supporting apparatus often leading to tooth loss, and is caused by a Gram-negative bacterial consortium that includes Tannerella forsythia. This bacterium expresses a virulence factor, the BspA, which drives periodontal inflammation by activating TLR2. The N-terminal portion of the BspA protein comprises a leucine-rich repeat (LRR) domain previously shown to be involved in the binding and activation of TLR2. The objective of the current study was to identify specific epitopes in the LRR domain of BspA that interact with TLR2. Our results demonstrate that a sequence motif GC(S/T)GLXSIT is involved in mediating the interaction of BspA with TLR2. Thus, our study has identified a peptide motif that mediates the binding of a bacterial protein to TLR2 and highlights the promiscuous nature of TLR2 with respect to ligand binding. This work could provide a structural basis for designing peptidomimetics to modulate the activity of TLR2 in order to block bacterially-induced inflammation.

Resolution of a Cystic Endodontic-Periodontal Lesion Utilizing Combined Apicoectomy and Guided Tissue Regeneration: A Case Report.

INTRODUCTION: Endodontic-periodontal combined lesions pose a treatment challenge for clinicians, especially when the lesion is persistent and does not show signs of healing after initial endodontic treatment. This case report describes interdisciplinary management of a non-healing combined endodontic-periodontal lesion related to a peri-apical cyst, through a combined approach of apicoectomy and guided tissue regeneration (GTR) with enamel matrix derivative (EMD). Most documented cases have been treated in a sequential manner, with minimal literature present on the effects of a combined approach utilizing EMD for the treatment of these lesions. CASE PRESENTATION: A 72-year-old male patient presented with an endodontic-periodontal lesion at tooth #31 initially treated with nonsurgical root canal therapy. The lesion was not responsive to initial endodontic treatment. The patient was informed of questionable prognosis, however wished to save the tooth. Tooth #31 was treated via a combination approach of apicoectomy with bioceramic putty retrograde filling, followed by GTR of the defect using allograft, EMD, and resorbable barrier membrane. The lesion was biopsied and diagnosed as a periapical cyst. Clinical and radiographic examination at 1 year showed resolution of lesion, reduction in probing depths, and good bone fill of the defect. CONCLUSION: Traditionally, endodontic-periodontal lesions, which were not responsive to initial therapy, would be given a questionable prognosis and be extracted. This case demonstrates that non-healing, peri-apical lesions may be cystic in nature and effectively managed utilizing a combined approach, with apicoectomy and GTR with EMD, to produce a stable outcome.

Effect of baking soda in dentifrices on plaque removal.

BACKGROUND: The prevention of dental caries and periodontal diseases targets control of dental plaque biofilm. In this context, chemical agents could represent a valuable complement to mechanical plaque control by reducing and controlling biofilm formation. METHODS: The literature on the effectiveness of different dentifrices has not, however, been carefully categorized. A lack of consensus exists among dental professionals on a recommendation for a universal dentifrice for plaque control. The authors reviewed the scientific data on the different properties of sodium bicarbonate (baking soda)-containing dentifrices and their effectiveness in plaque removal. RESULTS: The results of the literature search show that baking soda-containing dentifrices are ideal candidates to be considered as a universal dentifrice because baking soda is inexpensive, abundant in supply, highly biocompatible, exhibits specific antibacterial properties to oral microorganisms, has low abrasivity, and is effective in plaque biofilm removal. CONCLUSIONS: Although some patients may benefit from desensitizing or high fluoride-containing dentifrices, those with routine needs may find using dentifrices containing baking soda and fluoride effective. PRACTICAL IMPLICATIONS: Baking soda and fluoride dentifrices, therefore, may perhaps be considered as a criterion standard for patients with routine oral hygiene needs.

Comparison of 3 intranasal mists for anesthetizing maxillary teeth in adults: A randomized, double-masked, multicenter phase 3 clinical trial.

BACKGROUND: This double-masked, parallel-design, clinical trial assessed whether a combination nasal spray (K305; 3% tetracaine hydrochloride and 0.05% oxymetazoline hydrochloride) compared with a tetracaine-only spray and a placebo spray would be safer and superior in producing local anesthesia sufficient to complete a direct restorative procedure in maxillary nonmolar teeth. METHODS: The authors randomized eligible patients to receive K305 spray (n = 44), tetracaine hydrochloride spray (n = 44), or a placebo solution (n = 22). The authors compared the incidence of the primary efficacy end point-completion of the procedure without rescue local anesthetic-by means of a 1-tailed Fisher exact test. RESULTS: The end point incidence was 84.1% (95% confidence interval [CI], 69.9-93.4) with K305, 27.3% (95% CI, 15.0-42.8) with tetracaine only, and 27.3% (95% CI, 10.7-50.2) with placebo (P < .001 for K305 versus tetracaine only and versus placebo). Combination spray was associated with statistically significant but transient increases in blood pressure. The most frequent adverse events were rhinorrhea and nasal congestion, which resolved within 2 hours after treatment and occurred more often in the K305 group and tetracaine-only group. CONCLUSIONS: In this study population, the K305 combination nasal spray was safe and more effective in attaining pulpal anesthesia of maxillary teeth from premolar to premolar compared with tetracaine-only and placebo sprays. PRACTICAL IMPLICATIONS: The combination nasal spray might represent a valuable alternative to injected local anesthetic for patients undergoing invasive maxillary dental procedures. Clinicaltrials.gov: NCT01710787.