A novel technique to harvest bone autografts with mild local hyperthermia and enhanced osteogenic bone quality: a preclinical study in dogs.

BACKGROUND: Guided bone regeneration (GBR) involves collecting bone autografts with high bio-quality and efficiency. The current non-irrigated low-speed drilling has been limited for broader application in bone autograft harvest due to its low efficiency, inability to conduct buccal cortical perforation, and dependence on simultaneous implant placement. Increasing the drilling speed helps improve the efficiency but may incur thermal-mechanical bone damage. Most studies have addressed thermal reactions during bone drilling on non-vital models, which is irrelevant to clinical scenarios. Little has been known about bone's in vivo thermal profiles under non-irrigated higher-speed drilling and its influences on the resulting bone chips. AIM: A novel technique for bone harvest and cortical perforation via in-situ non-irrigated higher-speed drilling was proposed and investigated for the first time. METHODS: The third mandible premolars of eight beagles were extracted and healed for three months. Sixteen partial edentulous sites (left and right) were randomized into four groups for bone autograft harvest without irrigation: chisel, 50 rpm drilling, 500 rpm drilling, and 1000 rpm drilling. Bone chips were harvested on the buccal plates of the missing tooth. An infrared camera and an implantable thermocouple collaboratively monitored in vivo real-time bone temperature at the drilling sites. In vitro performances of cells from bone chips, including cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, mRNA transcriptional level of osteogenic genes and heat shock protein 70 (HSP-70), and HSP-70 expression at the protein level were also studied. RESULTS: 500 rpm produced mild local hyperthermia with a 2-6 °C temperature rise both on the cortical surface and inside the cortical bone. It also held comparable or enhanced cell performances such as cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, and osteogenic genes expression. CONCLUSIONS: In-situ non-irrigated higher-speed drilling at 500 rpm using a screw drill is versatile, efficient, and thermal friendly and improves the bio-quality of bone chips. Our novel technique holds clinical translational potential in GBR application.

The survival rates and risk factors of implants in the early stage: a retrospective study.

BACKGROUND: Few large-sample studies in China have focused on the early survival of dental implants. The present study aimed to report the early survival rates of implants and determine the related influencing factors. METHODS: All patients receiving dental implants at our institution between 2006 and 2017 were included. The endpoint of the study was early survival rates of implants, according to gender, age, maxilla/mandible, dental position, bone augmentation, bone augmentation category, immediate implant, submerged implant category, implant diameter, implant length, implant torque, and other related factors. Initially, SPSS22.0 was used for statistical analysis. The Chi-square test was used to screen all factors, and those with p < 0.05 were further introduced into a multiple logistic regression model to illustrate the risk factors for early survival rates of implants. RESULTS: In this study, we included 1078 cases (601 males and 477 females) with 2053 implants. After implantation, 1974 implants were retained, and the early survival rate was 96.15%. Patients aged 30-60 years (OR 2.392), with Class I bone quality (OR 3.689), bone augmentation (OR 1.742), immediate implantation (OR 3.509), and implant length < 10 mm (OR 2.972), were said to possess risk factors conducive to early survival rates. CONCLUSIONS: The early survival rate of implants in our cohort exceeded 96%, with risk factors including age, tooth position, bone quality, implant length, bone augmentation surgery, and immediate implantation. When the above factors coexist, implant placement should be treated carefully.

Differential expression of lncRNA/miRNA/mRNA and their related functional networks during the osteogenic/odontogenic differentiation of dental pulp stem cells.

Dentin-pulp regeneration requires dental pulp stem cells (DPSCs), but the role of long noncoding RNAs (lncRNAs) during this process remains unclear. Here, we cultured human DPSCs in osteogenic/odontogenic medium for 14 days and analyzed cells via RNA-sequencing. The data were validated by quantitative reverse transcription-polymerase chain reaction and lncRNA-microRNA (miRNA)-messenger RNA (mRNA) networks were constructed to reveal the potential competing endogenous RNA regulatory role of lncRNAs. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analysis were performed. One lncRNA, SNHG7, was identified and validated by genetic shRNA silencing. A total of 89 lncRNAs, 1,636 mRNAs, and 113 miRNAs were differentially expressed after differentiation. Bioinformatics identified an array of affected signaling pathways including phosphoinositide-3-kinase-protein kinase B, transforming growth factor-ß, and Wnt. mRNAs were enriched in cell migration, cell differentiation, stem cell development, ossification, and skeletal development. One lncRNA, SNHG7, was indentified to inhibit the odonto/osteogenic differentiation of DPSCs when silenced. In summary, we reveal several lncRNAs that significantly change during DPSC differentiation, including SNHG7. This reveals new targets for dentin-pulp complex regeneration and tissue engineering.

Pathogenic factors of maxillary sinus mucosal thickening observed by cone-beam computed tomography (CBCT).

OBJECTIVE: To explore the pathogenic factors associated with maxillary sinus mucosal thickening with Cone-beam computed Tomography (CBCT). METHODS: From 2016 through 2020, 93 patients with periapical periodontitis or periodontitis in the maxillary posterior dental region were selected. RESULTS: The preoperative thickness of the periodontitis group was significantly higher than that of the periapical periodontitis group (P < 0.05). The difference achieves statistical significance for the comparison of the thickness change with various severity of inflammation (F = 54.824, P = 0.000), the change with time (F = 312.741, P = 0.000). and the change with the interaction severity of inflammation and time（F = 86.132, P = 0.000). CONCLUSIONS: Patients with maxillary sinus mucosa thickening caused by periodontitis and periapical periodontitis should be extracted their infectious teeth and get thoroughly debridement. Maxillary sinus augmentation can perform favorable efforts 3-6 months after extracting teeth.

Effect of hydroxyapatite bioceramics on the growth of osteoblasts and HIF-α/VEGF signal axis in partial hypoxia environment in vitro.

BACKGROUND: Hydroxyapatite bioceramic is a kind of bone implant commonly used in oral clinic treatment. In the early stage of tissue repair, cells will suffer hypoxic due to the interruption of blood supply. OBJECTIVE: Studying the expression of osteoblasts in hypoxic environment will help us to understand the expression and response mechanism of osteoblasts at the implantation site of hydroxyapatite in the early stage of hypoxia. METHODS: MG63 osteoblast cell line was used in this study. The cells of normal group were incubated under normal oxygen and hydroxyapatite ceramics condition. The cells of hypoxia group were incubated under hypoxia (37∘C, 8% CO2, 8% O2, 86% N2) and hydroxyapatite ceramics condition. Cell proliferation was measured by CCK8 assay. Apoptosis was measured by flow cytometry. Serum alkaline phosphatase (ALP) activity was measured by ALP kit. Hypoxia inducible factor (HIF-α) and vascular endothelial growth factor (VEGF) were detected by Western blot. RESULTS: Compared to the normal group, the cells of hypoxia group showed a dramatically higher proliferation ability, especially at 48 h (P< 0.05). Due to hypoxia, cell apoptosis was induced, but there is no difference between these two groups. Interestingly, the ALP activity of hypoxia group was higher than that of normal group at 24 h and 48 h (P< 0.05). Mechanically, western blot result showed that the protein level of both HIF-α and VEGF were up-regulated in hypoxia group. CONCLUSIONS: Under hypoxia condition, hydroxyapatite bioceramics can promote the proliferation of MG63 osteoblasts, elevate the activity of alkaline phosphatase and upregulate HIF-α and VEGF expression without effect on apoptosis.

Clinical Outcomes of Alveolar Ridge Augmentation with In Situ Autogenous Block Bone: A Retrospective Review.

PURPOSE: To present clinical outcomes of alveolar ridge augmentation using in situ autogenous block bone and to compare the outcomes with previous studies. MATERIALS AND METHODS: The medical records of patients with a severe horizontal bone defect in a partially edentulous alveolar ridge (width < 3.5 mm), who received bone augmentation using in situ autogenous block bone, were retrospectively reviewed. After a 6-month or longer healing period, the augmentation effect was examined before implant placement. Cone beam computed tomography (CBCT) was performed before and after surgeries. The alveolar width of the bone grafts was measured on the CBCT images. RESULTS: A total of 16 patients (22 grafts) were included. Graft exposure was seen in three grafts, which were classified as failed cases. The augmentation volume at implant placement in the failed cases was significantly lower than that of the successful cases. There were no significant differences in augmentation between anterior maxillary and mandibular implant sites. CONCLUSION: Autogenous bone grafting using in situ block bone is an effective and reliable approach for horizontal bone augmentation in the mandible and anterior maxilla that eliminates second donor site morbidity. Complete release of the buccal flap and tension-free suture is the key to avoiding wound dehiscence and ensuring the effectiveness of bone augmentation.

Impact of High-Altitude Hypoxia on Early Osseointegration With Bioactive Titanium.

Nowadays, the bone osseointegration in different environments is comparable, but the mechanism is unclear. This study aimed to investigate the osseointegration of different bioactive titanium surfaces under normoxic or high-altitude hypoxic environments. Titanium implants were subjected to one of two surface treatments: (1) sanding, blasting, and acid etching to obtain a rough surface, or (2) extensive polishing to obtain a smooth surface. Changes in the morphology, proliferation, and protein expression of osteoblasts on the rough and smooth surfaces were examined, and bone formation was studied through western blotting and animal-based experiments. Our findings found that a hypoxic environment and rough titanium implant surface promoted the osteogenic differentiation of osteoblasts and activated the JAK1/STAT1/HIF-1α pathway in vitro. The animal study revealed that following implant insertion in tibia of rabbit, bone repair at high altitudes was slower than that at low altitudes (i.e., in plains) after 2weeks; however, bone formation did not differ significantly after 4weeks. The results of our study showed that: (1) The altitude hypoxia environment would affect the early osseointegration of titanium implants while titanium implants with rough surfaces can mitigate the effects of this hypoxic environment on osseointegration, (2) the mechanism may be related to the activation of JAK1/STAT1/HIF-1α pathway, and (3) our results suggest the osteogenesis of titanium implants, such as oral implants, is closely related to the oxygen environment. Clinical doctors, especially dentists, should pay attention to the influence of hypoxia on early osseointegration in patients with high altitude. For example, it is better to choose an implant system with rough implant surface in the oral cavity of patients with tooth loss at high altitude.

LncRNA ELF3-AS1 is involved in the regulation of oral squamous cell carcinoma cell proliferation by reprogramming glucose metabolism.

PURPOSE: The present study aims to investigate the role of ELF3-AS1 in oral squamous cell carcinoma (OSCC). PATIENTS AND METHODS: A total of 112 patients with OSCC were admitted in Guangdong Provincial Stomatological Hospital from March 2016 to March 2019. RT-qPCR, cells and transient transfections, cell proliferation rate measurements and Western blots were carried out to analyze the samples. RESULTS: In the present study, we showed that ELF3-AS1 and glucose transporter 1 (GLUT1) were both upregulated in OSCC tissues, and those two factors were positively correlated. In OSCC cells, ELF3-AS1 overexpression resulted in upregulation, while ELF3-AS1 siRNA silencing caused downregulated expression of GLUT1 and glucose uptake. ELF3-AS1 and GLUT1 overexpression resulted in increased rate of OSCC cells, while ELF3-AS1 and GLUT1 siRNA silencing resulted in decreased proliferation rate of OSCC cells. In addition, GLUT1 siRNA silencing attenuated the effects of ELF3-AS1 overexpression. CONCLUSION: Therefore, ELF3-AS1 promotes the proliferation of OSCC cells by reprogramming glucose metabolism.