Identifying an optimal approach for the placement of pterygoid implants: A 3D finite element analysis.

STATEMENT OF PROBLEM: A consensus on the optimal approach to the placement of pterygoid implants is lacking. PURPOSE: The purpose of this finite element analysis study was to determine the optimal approach to the placement of pterygoid implants by comparing biomechanical behavior. MATERIAL AND METHODS: An edentulous and moderately atrophic maxilla with the anatomic structure of the pterygomaxillary region was constructed. Complete arch restorations with 4 standard anterior implants and pterygoid implants in 3 approaches were simulated: L70, long pterygoid implants (4.1×18 mm) inclined at 70 degrees relative to the Frankfort horizontal plane with anchorage in the pterygoid process; L45, long pterygoid implants (4.1×20 mm) inclined at 45 degrees with anchorage in the pterygoid process; and S45, shorter pterygoid implants (4.1×13 mm) inclined 45 degrees without apical anchorage. The L70, L45, and S45 groups were classified as D or S depending on the bone quality: D3 (dense trabecular bone) or D4 (sparse trabecular bone). A total of 6 finite element models were built. The bone failure theory, based on the von Mises theory, was used to judge yielding of the trabecular bone. The von Mises stress (σVM) distribution was measured in the cortical bone, the trabecular bone, and on the implant surface. Deformation (DF) distribution was obtained for the entire bone (DFB) and bone surrounding the pterygoid implant (DFP). RESULTS: L70 showed a lower maximum σVM value (maxσVM), more uniform σVM distribution in the cortical bone, trabecular bone, and on the implant surface and a lower maximum DFp value (maxDFp), especially in the D4 bone. The biomechanical behaviors were similar in L45 and S45 with no stress distribution in the pterygoid process. In the D4 bone, L70, L45, and S45 exceeded the limited stress of the bone failure theory by 50%, 130%, and 130%, while all values were under the limit in D3 bone. CONCLUSIONS: The approach of pterygoid implants inclined at 70 degrees relative to the Frankfort plane with anchorage in the pterygoid process was optimal, providing improved biomechanical behavior. Clinically, in the case of D4 bone, the inclined angulation of pterygoid implants should be 70 degrees to minimize the risk of failure.

Long-term investigation of minimally invasive alcohol-based therapy as the treatment of odontogenic keratocyst:A retrospective cohort study.

The aim of this study was to evaluate the clinical efficacy of alcohol-based therapy for patients with large odontogenic keratocysts (OKCs). The study was implemented as a retrospective, single-center study. Patients treated with ethanol-based therapy for odontogenic keratocyst were retrospectively evaluated for baseline and postoperative data. The pre- and postoperative clinical situation and the extent of radiographic shrinkage were compared. The event is defined as the achievement of >50% reduction in cyst volume. The cyst reduction rate calculated on panoramic radiographs ranged from 7.4% to 99.9% (mean [standard deviation] 55.3% [27.9%]) and was statistically significant (P < 0.05). Specifically, it has been found that, radiographically, 47.6% of patients achieved >50% reduction in cyst volume within 12 months. The continuous cortical bone was rebuilt, and the cyst cavity was filled with regenerated trabecular bone. The 22 included patients presented with nonclinical problems, had no need for further intervention, and exhibited persistent impaction of the teeth. The results of this study demonstrated that ethanol-based therapy triggered marked radiographic reductions of large OKC, indicating that using this technique is efficient.

Glia-derived adenosine in the ventral hippocampus drives pain-related anxiodepression in a mouse model resembling trigeminal neuralgia.

Glial activation and dysregulation of adenosine triphosphate (ATP)/adenosine are involved in the neuropathology of several neuropsychiatric illnesses. The ventral hippocampus (vHPC) has attracted considerable attention in relation to its role in emotional regulation. However, it is not yet clear how vHPC glia and their derived adenosine regulate the anxiodepressive-like consequences of chronic pain. Here, we report that chronic cheek pain elevates vHPC extracellular ATP/adenosine in a mouse model resembling trigeminal neuralgia (rTN), which mediates pain-related anxiodepression, through a mechanism that involves synergistic effects of astrocytes and microglia. We found that rTN resulted in robust activation of astrocytes and microglia in the CA1 area of the vHPC (vCA1). Genetic or pharmacological inhibition of astrocytes and connexin 43, a hemichannel mainly distributed in astrocytes, completely attenuated rTN-induced extracellular ATP/adenosine elevation and anxiodepressive-like behaviors. Moreover, inhibiting microglia and CD39, an enzyme primarily expressed in microglia that degrades ATP into adenosine, significantly suppressed the increase in extracellular adenosine and anxiodepressive-like behaviors. Blockade of the adenosine A2A receptor (A2AR) alleviated rTN-induced anxiodepressive-like behaviors. Furthermore, interleukin (IL)-17A, a pro-inflammatory cytokine probably released by activated microglia, markedly increased intracellular calcium in vCA1 astrocytes and triggered ATP/adenosine release. The astrocytic metabolic inhibitor fluorocitrate and the CD39 inhibitor ARL 67156, attenuated IL-17A-induced increases in extracellular ATP and adenosine, respectively. In addition, astrocytes, microglia, CD39, and A2AR inhibitors all reversed rTN-induced hyperexcitability of pyramidal neurons in the vCA1. Taken together, these findings suggest that activation of astrocytes and microglia in the vCA1 increases extracellular adenosine, which leads to pain-related anxiodepression via A2AR activation. Approaches targeting astrocytes, microglia, and adenosine signaling may serve as novel therapies for pain-related anxiety and depression.

Engineered Extracellular Vesicles Driven by Erythrocytes Ameliorate Bacterial Sepsis by Iron Recycling, Toxin Clearing and Inflammation Regulation.

Sepsis poses a significant challenge in clinical management. Effective strategies targeting iron restriction, toxin neutralization, and inflammation regulation are crucial in combating sepsis. However, a comprehensive approach simultaneously targeting these multiple processes has not been established. Here, an engineered apoptotic extracellular vesicles (apoEVs) derived from macrophages is developed and their potential as multifunctional agents for sepsis treatment is investigated. The extensive macrophage apoptosis in a Staphylococcus aureus-induced sepsis model is discovered, unexpectedly revealing a protective role for the host. Mechanistically, the protective effects are mediated by apoptotic macrophage-released apoEVs, which bound iron-containing proteins and neutralized α-toxin through interaction with membrane receptors (transferrin receptor and A disintegrin and metalloprotease 10). To further enhance therapeutic efficiency, apoEVs are engineered by incorporating mesoporous silica nanoparticles preloaded with anti-inflammatory agents (microRNA-146a). These engineered apoEVs can capture iron and neutralize α-toxin with their natural membrane while also regulating inflammation by releasing microRNA-146a in phagocytes. Moreover, to exploit the microcosmic movement and rotation capabilities, erythrocytes are utilized to drive the engineered apoEVs. The erythrocytes-driven engineered apoEVs demonstrate a high capacity for toxin and iron capture, ultimately providing protection against sepsis associated with high iron-loaded conditions. The findings establish a multifunctional agent that combines natural and engineered antibacterial strategies.

A Study of Two Novel Techniques for One-stage Closure of Chronic Oroantral Fistula and Sinus Floor Lift.

PURPOSE: This study aimed to compare two novel techniques for chronic oroantral fistula (OAF) closure combined with maxillary sinus floor elevation. MATERIALS AND METHODS: Ten patients who had implant installation needs but suffered from a chronic OAF were enrolled in the study from January 2016 to June 2021. The technique applied involved OAF closure and simultaneous sinus floor elevation by either a transalveolar or lateral window approach. Bone graft material evaluation results, postoperative clinical symptoms and complications were compared between the two groups. Student's t -test and χ 2 test were used to analyze the results. RESULTS: In this study, 5 patients with a chronic OAF were treated with the transalveolar approach (group I), and 5 were treated with the lateral window approach (group II). The alveolar bone height was significantly higher in group II than in group I ( P ＜0.001). The pain at 1 day ( P =0.018) and 3 days ( P =0.029) postoperatively and facial swelling at 7 days ( P =0.016) postoperatively were obviously greater in group II than in group I. There were no severe complications in either group. CONCLUSIONS: The techniques combined OAF closure with sinus lifting to reduce surgical frequency and risks. The transalveolar approach resulted in milder postoperative reactions, but the lateral approach could provide more bone volume.

3D GelMA ICC Scaffolds Combined with SW033291 for Bone Regeneration by Modulating Macrophage Polarization.

Despite the interaction between bone marrow mesenchymal stem cells (BMSCs) and macrophages has been found to play a critical role in repairing bone defects, it remains a challenge to develop a desirable tissue engineering scaffold for synchronous regulation of osteogenic differentiation and macrophage polarization. Herein, this study proposed a novel strategy to treat bone defects based on three-dimensional Gelatin Methacryloyl Inverted Colloidal Crystal (3D GelMA ICC) scaffold and an active 15-hydroxyprostaglandin dehydrogenase (15-PGDH) inhibitor SW033291. Specifically, the 3D GelMA ICC scaffolds were firstly prepared by colloidal templating method, which displayed good cell attachment and promoted intercellular interaction among macrophage and BMSCs due to its uniform pore interconnectivity. By combined use of SW033291, the release of Prostaglandin E2 (PGE2) from BMSCs on the GelMA ICC scaffold was significantly upregulated and macrophages M2 polarization was markedly increased. In turn, BMSCs proliferation and osteogenic differentiation was further enhanced by paracrine regulation of M2 macrophage, and thus finally caused more in vivo new bone formation by shaping up a pro-regenerative local immune microenvironment surrounding GelMA ICC scaffold. Our findings demonstrate the potential of 3D GelMA ICC scaffolds combined with SW033291 to become an effective tissue engineering strategy for bone regeneration.

Progression of squamous cell carcinoma is regulated by miR-139-5p/CXCR4.

miR-139-5p has a tumor suppressor effect in some cancers and negatively regulates CXCR4. To this end, we examined the expression and mechanism of of action of miR-139-5p and CXCR4 in oral squamous cell carcinoma (OSCC). miRNA-139-5p was down-regulated whereas CXCR4 was increased in tissues and cells of OSCC. Moreover, low expression of miR-139-5p was associated with a low survival. Overexpression of miR-139-5p in OSCC inhibited in vitro and in vivo cell proliferation and in vitro mobility of OSCC and inhibited the expression of WNT responsive c-myc, cyclinD1, and Bcl-2, and such effects were all reversible by an inhibitor of miR-139-5p or over-expression of CXCR4. The inverse relation between expression of miR-139-5p and CXCR4 might be related to the fact that miR-139-5p negatively regulates CXCR4 expression by virtue of direct binding. These findings underscore the importance of miR-139-5p and CXCR4 in regulation of OSCC.

Unconventional gas-based bottom-up, meter-area-scale fabrication of hydrogen-bond free g-CN nanorod arrays and coupling layers with TiO2 toward high-efficiency photoelectrochemical performance.

Meter-scale uniform g-CN nanorod (NR) arrays were directly grown on an FTO glass using an unprecedented vacuum magnetic filtered arc ion plating system for enhanced photoelectrochemical (PEC) performance. The construction of the g-CN film is based on the substrate deposition of the direct reaction of ionized carbon and nitrogen species, a gas-based bottom-up approach, distinctly different from the traditional powder deposition and thermal vapor pathways. The g-CN film exhibits obvious advantages over conventional ones in the application of PEC: (1) direct reaction of C and N species allows the formation of the g-CN without intralayer hydrogen bonds, which significantly reduces intralayer photogenerated charge carriers transfer resistance; (2) the g-CN exhibits the NR array structure and comprises considerably numerous layers stacking by stacking and vertically standing on the FTO substrate, which facilitates the photogenerated charges transfer and increases the contact area with electrolyte; (3) the robust mechanical strength of the g-CN NR film with the FTO substrate not only favors the effective charge transport but also allows long-term practical application against abrasion; (4) the gas-based bottom-up approach enables the g-CN to easily couple with, including but not limited to, TiO2 NR array to form heterostructures to further improve charge separation.

Interface Manipulation to Improve Plasmon-Coupled Photoelectrochemical Water Splitting on α-Fe2 O3 Photoanodes.

The plasmon resonance effect of metal nanoparticles (NPs) offers a promising route to improve the solar energy conversion efficiency of semiconductors. In this study, it is revealed that hot electrons generated by the plasmon resonance effect of Au NPs tend to inject into the surface states instead of the conduction band of Fe2 O3 photoanodes, and then severe surface recombination occurs. Such an electron-transfer process seems to be independent of external applied potentials, but is sensitive to metal-semiconductor interface properties. Passivating the surface states of Fe2 O3 with a noncatalytic Al2 O3 layer can construct an effective resonant energy-transfer interface between Ti-doped Fe2 O3 (Ti-Fe2 O3 ) and Au NPs. In such a Ti-Fe2 O3 /Al2 O3 /Au electrode configuration, the enhanced photoelectrochemical (PEC) water-splitting performance can be attributed to the following two factors: 1) in the non-light-responsive wavelength range of Au NPs, both the relaxing Fermi pinning effect of the Al2 O3 passivation layer and the higher work function of Au enlarge band bending; thus promoting the charge separation; and 2) in the light-responsive wavelength range of Au NPs, the effective resonant energy transfer contributes to light harvesting and conversion. The interface manipulation proposed herein may provide a new route to design efficient plasmonic PEC devices for energy conversion.

Silicon Photoanodes Partially Covered by Ni@Ni(OH)2 Core-Shell Particles for Photoelectrochemical Water Oxidation.

Two obstacles hindering solar energy conversion by photoelectrochemical (PEC) water-splitting devices are the charge separation and the transport efficiency at the photoanode-electrolyte interface region. Herein, core-shell-structured Ni@Ni(OH)2 nanoparticles were electrodeposited on the surface of an n-type Si photoanode. The Schottky barrier between Ni and Si is sensitive to the thickness of the Ni(OH)2 shell. The photovoltage output of the photoanode increases with increasing thickness of the Ni(OH)2 shell, and is influenced by interactions between Ni and Ni(OH)2 , the electrolyte screening effect, and the p-type nature of the Ni(OH)2 layer. Ni@Ni(OH)2 core-shell nanoparticles with appropriate shell thicknesses coupled to n-type Si photoanodes promote the separation of photogenerated carriers and improve the charge-injection efficiency to nearly 100 %. An onset potential of 1.03 V versus reversible hydrogen electrode (RHE) and a saturated current density of 36.4 mA cm-2 was obtained for the assembly.

Efficacy of the technique of piezoelectric corticotomy for orthodontic traction of impacted mandibular third molars.

Our aim was to assess the efficacy of piezoelectric corticotomy for orthodontic traction of mandibular third molars close to the inferior alveolar nerve. Thirty patients with impacted third molars close to the nerve were included in the study, 15 of whom were treated with conventional orthodontic traction and 15 with piezoelectric corticotomy. We recorded duration of treatment including exposure and orthodontic traction, and time to the final extraction. Postoperative complications including trismus, swelling, and pain were also noted. Alveolar bone levels mesial and distal to the second molars were evaluated on cone-beam computed tomographic (CT) images. Student's t test was used to assess the significance of differences between the groups. After orthodontic treatments all impacted third molars were successfully removed from the inferior alveolar nerve without neurological damage. The mean (SD) duration of surgical exposure in the piezoelectric corticotomy group was significantly longer than that in the conventional group (p=0.01). The mean (SD) duration of traction was 4 (2.3) months after piezoelectric corticotomy, much shorter than the 7.5 (1.3) months in the conventional group (p=0.03). There were no significant differences in postoperative complications between the groups. There was a significant increase in the distal alveolar height of second molars after treatment in both groups (p<0.01). We conclude that the use of piezoelectric corticotomy allows more efficient and faster traction of third molars with a close relation between the root and the inferior alveolar nerve, although it took longer than the traditional technique.

Functional surgery for the treatment of dentigerous cyst in the maxillary sinus.

BACKGROUND: Dentigerous cyst (DC) in the maxillary sinus is rarely seen. Several complications are observed after the Caldwell-Luc operation, which is combined with endoscopy. Still, a more perfect treatment method is yet to be discovered. OBJECTIVES: The purpose of this study was to explore and assess a new functional surgical treatment with fewer complications, which not only insured normal maxillary sinus cilia restoration and bony integrity but also did little damage to maxillary sinus natural ostium. METHODS: Dentigerous cyst in the maxillary sinuses of 20 patients had conditions diagnosed through radiographic imaging and the locating of bone windows' positions according to preoperative 3-dimensional computed tomography (CT) (3D CT). All the patients underwent a functional surgery in which a bony lid was created anteriolaterally of maxillary sinus with piezosurgery and reimplanted by titanium plates after enucleating the cyst, leaving the maxillary sinus mucosa in place with or without endoscope's assistance. Therapeutic efficacy was evaluated by clinical examination and radiographic imaging at regular intervals; the longest follow-up was 24 months. RESULTS: All the patients recovered except for one, who underwent plate removal and radical maxillary sinusotomy owing to infection. Patients were asymptomatic, and CT images showed integrated maxillary bone. Extrusion deformation of the sinus was improved to different extents after 6 to 24 months of follow-up. CONCLUSIONS: Functional surgery for the treatment of DC in the maxillary sinus is a new approach and has the advantages of less surgical trauma, restoration of mucosa and bony wall, and more satisfactory results.

An orthodontic technique for minimally invasive extraction of impacted lower third molar.

PURPOSE: To present a novel orthodontic approach for minimally invasive extraction of impacted mandibular third molars (M3s) close to the inferior alveolar nerve (IAN). PATIENTS AND METHODS: Eight patients (8 M3s) requiring extraction of M3s were included in this study; there were 2 cases of horizontal impaction, 4 of mesioangular impaction, and 2 of vertical impaction. Cone-beam computed tomogram showed that the roots of impacted M3s in 2 cases interrupted the cortices of the mandibular canal, and those in the other 6 cases were very close to the IAN. Orthodontic treatment was performed in this study. The crowns of 5 impacted teeth were surgically exposed before the application of the orthodontic device, whereas bonding was performed directly to the occlusal surface of the other 3 M3s, which had partially erupted. The opposing maxillary M3s were removed in 3 cases. One-step orthodontic extraction was applied to vertically impacted M3s and 2-step treatment was applied to horizontally or mesioangularly impacted M3s. Success was defined as the separation of the impacted tooth from the IAN as visualized on cone-beam computed tomogram. RESULTS: After orthodontic treatment, all impacted M3s were extruded and separated from the IAN (mean, 6.6 months; range, 4 to 10 months), without any neurologic consequences. The average time of extraction was 5 minutes. In all 8 cases, new bone formation occurred distal to the adjacent second molar. CONCLUSION: This orthodontic technique may be a minimally invasive approach for the extraction of impacted M3s adjacent to the IAN, with a decreased risk of paresthesias and with osteoperiodontal advantages.

Anatomic relationship between impacted third mandibular molar and the mandibular canal as the risk factor of inferior alveolar nerve injury.

Our aim was to explore the relation between the site of the mandibular canal and neurosensory impairment after extraction of impacted mandibular third molars. We organised a retrospective study of 537 extractions in 318 patients in which the affected tooth was intersected by the mandibular canal. This was verified by cone-beam computed tomography (CBCT), and we analysed the relation between the site of the canal and the likelihood of injury to the inferior alveolar nerve (IAN) after extraction of the third molar. The relation between the position of the root of the tooth and the mandibular canal was categorised into 4 groups: I=root above the canal; II=on the buccal side; III=on the lingual side; and IV=between the roots. The overall rate of neurosensory impairment after extraction was 6% (33/537). It occurred in 9/272 patients (3%) in group 1, 16/86 (19%) in group II, and in 8/172 (5%) in group III. There was no neurosensory impairment in group IV where the canal was between the roots. There were significant differences between group II and groups I and III (p<0.01), but not between groups I and III (p=0.32). The risk of damage to the inferior alveolar nerve is increased if third molars intersect with the mandibular canal, particularly on its buccal side.

Clinicopathologic features of dentigerous cysts in the maxillary sinus.

Dentigerous cyst (DC) in the maxillary sinus is extremely rare. This study evaluated the clinical features, etiologic factors, imaging, treatment, and signs and symptoms of this type of DC. Clinical symptoms, radiographic findings, surgical methods, and histopathologic findings of 4 patients with DCs in the maxillary sinus were evaluated. In addition, we reviewed the literature reports of DCs in the maxillary sinus over the past 40 years. Our 4 patients with DC in the maxillary sinus showed the following results: (1) all the patients were males at first 3 decades of age, (2) swelling and/or yellow-green pus discharges from pharyngeal cavity were common symptoms, (3) the involved teeth in the DC were the maxillary third molar teeth and supernumerary teeth, and (4) Caldwell-Luc approach was performed in these 4 patients. The patients with DC in the maxillary sinus should be evaluated thoroughly by extraoral and intraoral examinations, proper diagnostic imaging procedures, and pathologic examination to avoid misdiagnosis of maxillary sinusitis. The standard treatment for DC in the maxillary sinus is often removed by Caldwell-Luc approach. Furthermore, marsupialization or functional endoscopic sinus surgery may be performed because of the size, location of the cysts, or the age of the patients.

Dentigerous cysts associated with impacted supernumerary teeth in the anterior maxilla.

Dentigerous cysts are thought to be caused by a developmental abnormality derived from the reduced enamel epithelium of the tooth forming organ. Most typical dentigerous cysts are those associated with the third molar teeth of the mandible, but rarely involve impacted supernumerary teeth in the anterior maxilla. Swelling and/or pain may be the major complaints of the patients. Herein, we review the literature spanning the past 22 years concerning dentigerous cysts associated with supernumerary teeth in the anterior maxilla, and present four additional cases with emphasis given to the clinicopathological characteristics of this type of dentigerous cyst.