The application of a new clear removable appliance with an occlusal splint in early anterior crossbite.

BACKGROUND: The effectiveness of anterior crossbite treatment in preschool-aged children depends on the treatment design and patient compliance. Common early treatment appliances with steel wires and acrylic resin can bring about numerous problems, such as toothache, sore gums and mucous membrane injury. The aim of this study was to propose a new clear removable appliance to provide preschool-age children with an improved experience of early occlusal interference treatment. METHODS: Appliances were designed with the help of 3-dimensional (3D) digital reconstruction oral models and fabricated using 3D printing technology and the pressed film method. Then, the mechanical properties of the original dental coping sheet and thermoformed aligners were assessed in a simulated intraoral environment. Preschool-age participants who displayed anterior crossbite were recruited in this study. Records (photographs and impressions) were taken before the treatment (T1), during the treatment (T2) and at the end of the treatment (T3). The effects of treatment were evaluated by clinical examination and questionnaires. RESULTS: Normal degrees of overbite and overjet in the primary dentition were achieved using this new appliance. Dental and soft tissue relationships were improved. Questionnaires showed that the safety evaluation, degree of comfort and convenience grades of the appliance were all relatively high. CONCLUSION: This explorative study demonstrates that our new clear removable appliance is able to correct early-stage anterior crossbite in a safe, comfortable, convenient and efficient way. Thus, it is a promising method to correct a certain type of malocclusion, and its clinical use should be promoted in the future.

A Full-Digital Technique to Mount a Maxillary Arch Scan on a Virtual Articulator.

Mounting casts accurately on an articulator is a prerequisite for the treatment planning/execution of complex dental cases that require occlusal rehabilitation. A full digital approach to transfer the position of maxillary dentition to a virtual articulator, by using intraoral scans and cone beam computed tomography (CBCT) files is presented. This technique offers reduced chairside time and the flexibility of choosing the orientation plane. It can be used in orthognathic surgeries, complex interdisciplinary treatments requiring a CBCT scan with a large field of view, or treatments that already have the head CT or CBCT scans from previous diagnosis/treatment.

Chin remodeling in a patient with bimaxillary protrusion and open bite by using mini-implants for temporary anchorage.

Patients with bimaxillary protrusion may have an unattractive profile with a retruded chin contour. Correction of the severely protrusive anterior alveolar bone and teeth combined with a moderate open bite without orthognathic surgery can be challenging. This case report describes the orthodontic treatment of a woman with severe bimaxillary protrusion and a moderate open bite. Excellent chin morphology and facial appearance were obtained with the extraction of 4 first premolars and 4 third molars, and total distalization of both arches with 4 mini-implants, one in each quadrant between the second premolar and the first molar. The total treatment time was 30 months.

PPAR-γ activation promotes xenogenic bioroot regeneration by attenuating the xenograft induced-oxidative stress.

Xenogenic organ transplantation has been considered the most promising strategy in providing possible substitutes with the physiological function of the failing organs as well as solving the problem of insufficient donor sources. However, the xenograft, suffered from immune rejection and ischemia-reperfusion injury (IRI), causes massive reactive oxygen species (ROS) expression and the subsequent cell apoptosis, leading to the xenograft failure. Our previous study found a positive role of PPAR-γ in anti-inflammation through its immunomodulation effects, which inspires us to apply PPAR-γ agonist rosiglitazone (RSG) to address survival issue of xenograft with the potential to eliminate the excessive ROS. In this study, xenogenic bioroot was constructed by wrapping the dental follicle cells (DFC) with porcine extracellular matrix (pECM). The hydrogen peroxide (H2O2)-induced DFC was pretreated with RSG to observe its protection on the damaged biological function. Immunoflourescence staining and transmission electron microscope were used to detect the intracellular ROS level. SD rat orthotopic transplantation model and superoxide dismutase 1 (SOD1) knockout mice subcutaneous transplantation model were applied to explore the regenerative outcome of the xenograft. It showed that RSG pretreatment significantly reduced the adverse effects of H2O2 on DFC with decreased intracellular ROS expression and alleviated mitochondrial damage. In vivo results confirmed RSG administration substantially enhanced the host's antioxidant capacity with reduced osteoclasts formation and increased periodontal ligament-like tissue regeneration efficiency, maximumly maintaining the xenograft function. We considered that RSG preconditioning could preserve the biological properties of the transplanted stem cells under oxidative stress (OS) microenvironment and promote organ regeneration by attenuating the inflammatory reaction and OS injury.

Personalized 3D-Printed Scaffolds with Multiple Bioactivities for Bioroot Regeneration.

Recent advances in 3D printing offer a prospective avenue for producing transplantable human tissues with complex geometries; however, the appropriate 3D-printed scaffolds possessing the biological compatibility for tooth regeneration remain unidentified. This study proposes a personalized scaffold of multiple bioactivities, including induction of stem cell proliferation and differentiation, biomimetic mineralization, and angiogenesis. A brand-new bioink system comprising a biocompatible and biodegradable polymer is developed and reinforced with extracellular matrix generated from dentin tissue (treated dentin matrix, TDM). Adding TDM optimizes physical properties including microstructure, hydrophilicity, and mechanical strength of the scaffolds. Proteomics analysis reveals that the released proteins of the 3D-printed TDM scaffolds relate to multiple biological processes and interact closely with each other. Additionally, 3D-printed TDM scaffolds establish a favorable microenvironment for cell attachment, proliferation, and differentiation in vitro. The 3D-printed TDM scaffolds are proangiogenic and facilitate whole-thickness vascularization of the graft in a subcutaneous model. Notably, the personalized TDM scaffold combined with dental follicle cells mimics the anatomy and physiology of the native tooth root three months after in situ transplantation in beagles. The remarkable in vitro and in vivo outcomes suggest that the 3D-printed TDM scaffolds have multiple bioactivities and immense clinical potential for tooth-loss therapy.

Peroxisome proliferator-activated receptor gamma preserves intracellular homeostasis of insulin-resistant periodontal ligament stem cells.

Background: Diabetes and periodontitis develop and influence each other. The peroxisome proliferator-activated receptor gamma (PPARγ) agonist rosiglitazone (RSG) controls blood glucose and hence the systemic diseases associated with diabetes by increasing the sensitivity of tissues to insulin. However, whether and how RSG can treat diabetic periodontitis is poorly understood. Methods: Insulin-resistant periodontal ligament stem cells (IR-PDLSCs) were induced by glucosamine (18 mM, 24 h) in the presence or absence of RSG or GW9662 (a PPARγ antagonist). The glucose uptake rate was tested to evaluate insulin sensitivity. A scratch test was carried out to measure cell proliferation and motility. We used 2,7-dichlorodihydrofluorescein diacetate (DFCH-DA) and JC-1 kits to detect oxidative stress (OS), and cytoskeleton staining and Calcein-AM/PI kits were used to determine cell viability. Interferon-gamma (IFN-γ) and interleukin-10 (IL-10) ELISA kits were used to evaluate inflammation levels. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot (WB) analysis were used to assess the expression of osteogenic/odontogenic differentiation-related genes or proteins. Results: Our results showed that RSG exhibited a protective effect on IR-PDLSCs, with increased insulin sensitivity and migration efficiency, an alleviation of glucosamine-induced OS, and a downregulated pro-inflammatory cytokine secretion through activation of PPARγ receptors. Moreover, RSG alleviated the suppressed odontogenic differentiation ability of IR-PDLSCs. Conclusions: RSG preserves the biological functions of IR-PDLSCs in maintaining intracellular homeostasis by increasing insulin sensitivity, reducing OS, and suppressing inflammation.

Camouflage treatment guided by facial improvement in hyperdivergent skeletal class II malocclusion.

Background: To detect parameters associated with the craniomaxillofacial system that could be altered during hyperdivergent skeletal class II malocclusion camouflage treatment for better profile improvement. Methods: Forty-two subjects with hyperdivergent skeletal class II malocclusion who had finished their orthodontic treatments and achieved good soft tissue responses were included in this study. Cephalometric analyses of these patients were taken before (T1) and after (T2) treatment. Measurements were made at each treatment stage and analyzed within and between groups. Results: No obvious decrease in the cant of occlusal plane (OP) (the line of point L1 and point L7) and mandibular plane (MP) was observed. However, an obvious decrease in the cant of the posterior occlusal plane (POP) and the angle of plane NA and plane NB (ANB) and a significant increase in the distance from the condylar center (Dc) to OP (DPO) were observed in the subjects (P<0.05). Conclusions: Decreased POP canting and increased DPO values play a vital role in profile improvement. Sagittal discrepancies might be considerably alleviated by a decreasing ANB angle [especially the sella nasion A point (SNA) angle]. Therefore, to attain a successful camouflage treatment of hyperdivergent skeletal class II malocclusion, treatment should be targeted towards finding an alternative to control POP canting, including reducing crowding in the posterior arch, as well as modifying and intruding molars to an upright and lower position.

Improvement of ECM-based bioroot regeneration via N-acetylcysteine-induced antioxidative effects.

BACKGROUND: The low survival rate or dysfunction of extracellular matrix (ECM)-based engineered organs caused by the adverse effects of unfavourable local microenvironments on seed cell viability and stemness, especially the effects of excessive reactive oxygen species (ROS), prompted us to examine the importance of controlling oxidative damage for tissue transplantation and regeneration. We sought to improve the tolerance of seed cells to the transplant microenvironment via antioxidant pathways, thus promoting transplant efficiency and achieving better tissue regeneration. METHODS: We improved the antioxidative properties of ECM-based bioroots with higher glutathione contents in dental follicle stem cells (DFCs) by pretreating cells or loading scaffolds with the antioxidant NAC. Additionally, we developed an in situ rat alveolar fossa implantation model to evaluate the long-term therapeutic effects of NAC in bioroot transplantation. RESULTS: The results showed that NAC decreased H2O2-induced cellular damage and maintained the differentiation potential of DFCs. The transplantation experiments further verified that NAC protected the biological properties of DFCs by repressing replacement resorption or ankylosis, thus facilitating bioroot regeneration. CONCLUSIONS: The following findings suggest that NAC could significantly protect stem cell viability and stemness during oxidative stress and exert better and prolonged effects in bioroot intragrafts.

Xenoextracellular matrix-rosiglitazone complex-mediated immune evasion promotes xenogenic bioengineered root regeneration by altering M1/M2 macrophage polarization.

Xenogenic extracellular matrix (xECM)-based organ transplantation will be a promising approach to address the problem of donor shortage for allotransplantation, which has achieved great success in organ regeneration. However, current approaches to utilize xECM-based organ have limited capacity to yield the host a biofriendly microenvironment for long-term immunity homeostasis, compromising the application of these xenografts for repairing and replacing damaged tissues. As the key innate immune cells, macrophages directly determine the prognosis of xenografts in long term. However, it has not been fully elucidated that how to modulate their biological behavior for microenvironment homeostasis in tissue reconstruction. In this study, we report a robust strategy to impart an immunosuppressive surface to naturally sponge-like porous xECM scaffolds by loading rosiglitazone (RSG) to activate peroxisome proliferators receptors-γ (PPAR-γ). The resultant xECM-RSG complex, enabling RSG to be delivered sequentially and continuously to cells without obvious systemic side effects, is recognized as "self" to escape immune monitoring in local immunoregulation by downregulating the expression of proinflammatory NOS2+ M1 macrophages and oxygen species (ROS) through suppressing NF-κB expression, greatly facilitating the regeneration of enthesis anchoring between the transplanted xenograft and host in both heterotopic and orthotopic models. The newly formed bio-root is morphologically and biomechanically equivalent to native tooth root with a significant expression of odontogenic differentiation-related critical proteins. Therefore, the PPAR-γ-NF-κB axis activated by the xECM-RSG complex enables the xenografts to converse towards M2 macrophages with a modest immunosuppressive capacity for facilitating in xECM-based tissue or organ regeneration.

Worn is born: The role of the maxillo-mandibular relation in management of worn dentition.

Worn dentition, often accompanied by occlusion changes such as reduced vertical dimension, poses a big challenge to both diagnosis and treatment. Current established causes fail to explain the observed tooth wearing patterns, and the treatments based on the documented pathogeneses are often unpredictable and require frequent maintenance. From the perspective of stomatognathic system, we postulate that the role of maxillo-mandibular relation is a crucial part in the tooth wear progression patterns, and should be well addressed in treatment planning. Incompatible occlusion with the inherent tendency of maxillo-mandibular relation has a profound effect on either wearing of natural teeth or failures of restorations. With the aid of cephalometrics and analysis of occlusion it is now possible to reduce this fallacy and achieve a harmony by re-designing the occlusion. According to our treated worn dentition cases, the restoring treatment guided by the tendency of maxillo-mandibular relation showed very promising results.