Biomechanical analysis of the maxillary sinus floor membrane during internal sinus floor elevation with implants at different angles of the maxillary sinus angles.

OBJECTIVE: This study analyzed and compared the biomechanical properties of maxillary sinus floor mucosa with implants at three different maxillary sinus angles during a modified internal sinus floor elevation procedure. METHODS: 3D reconstruction of the implant, maxillary sinus bone, and membrane were performed. The maxillary sinus model was set at three different angles. Two internal maxillary sinus elevation models were established, and finite element analysis was used to simulate the modified maxillary sinus elevation process. The implant was elevated to 10 mm at three maxillary sinus angles when the maxillary sinus floor membrane was separated by 0 and 4 mm. The stress of the maxillary sinus floor membrane was analyzed and compared. RESULTS: When the maxillary sinus floor membrane was separated by 0 mm and elevated to 10 mm, the peak stress values of the implant on the maxillary sinus floor membrane at three different angles were as follows: maxillary sinus I: 5.14-78.32 MPa; maxillary sinus II: 2.81-73.89 MPa; and maxillary sinus III: 2.82-51.87 MPa. When the maxillary sinus floor membrane was separated by 4 mm and elevated to 10 mm, the corresponding values were as follows: maxillary sinus I: 0.50-7.25 MPa; maxillary sinus II: 0.81-16.55 MPa; and maxillary sinus III: 0.49-22.74 MPa. CONCLUSION: The risk of sinus floor membrane rupture is greatly reduced after adequate dissection of the maxillary sinus floor membrane when performing modified internal sinus elevation in a narrow maxillary sinus. In a wide maxillary sinus, the risk of rupture or perforation of the wider maxillary sinus floor is reduced, regardless of whether traditional or modified internal sinus elevation is performed at the same height.

Amino acid formula induces microbiota dysbiosis and depressive-like behavior in mice.

Amino acid formula (AAF) is increasingly consumed in infants with cow's milk protein allergy; however, the long-term influences on health are less described. In this study, we established a mouse model by subjecting neonatal mice to an amino acid diet (AAD) to mimic the feeding regimen of infants on AAF. Surprisingly, AAD-fed mice exhibited dysbiotic microbiota and increased neuronal activity in both the intestine and brain, as well as gastrointestinal peristalsis disorders and depressive-like behavior. Furthermore, fecal microbiota transplantation from AAD-fed mice or AAF-fed infants to recipient mice led to elevated neuronal activations and exacerbated depressive-like behaviors compared to that from normal chow-fed mice or cow's-milk-formula-fed infants, respectively. Our findings highlight the necessity to avoid the excessive use of AAF, which may influence the neuronal development and mental health of children.

Modified internal sinus elevation for patients with low residual bone height: A retrospective clinical study.

BACKGROUND: We have modified the internal sinus elevation by combining it with the sinus mucoperiosteum stripping procedure, which further increases the indications for the internal lift. Similar long-term clinical follow-up studies and three-dimensional finite element analyses are rare. OBJECTIVE: This study aimed to investigate the feasibility of the modified internal sinus floor elevation method in patients with low residual bone height using a three-dimensional (3D) finite element model and report on the long-term outcomes. MATERIALS AND METHODS: Overall, 99 implants were placed in 86 patients. All patients were followed-up for 3-24 months. The modified internal sinus floor elevation was dynamically simulated using a 3D finite element model, and the stress of the sinus membrane was measured. RESULTS: In trial group A (modified internal sinus floor elevation group), 57 implants were placed in 52 patients. The sinus floor height was lifted by 6.5 mm (95%confidence interval (CI): 6.2-6.8). The perforation rate was 8.8%, and the implant survival rate was 96.5%. In control group B (external sinus floor elevation group), 42 implants were placed in 34 patients. The sinus floor height was lifted by 8.8 mm (95%CI: 8.4-9.3). The perforation rate was 14.3%, and the implant survival rate was 100%. In trial group A, compared with the control group B, perforation decreased by 5.5% (odds ratio = 0.50 and 95%CI: 0.14-1.78; p = 0.282), and the sinus floor lift height was 2.3 mm lower (95%CI, 1.8-2.9; p < 0.001). The finite element analysis showed that the peak stress of the sinus membrane increased with an increase in height elevation and degree of membrane separation. CONCLUSION: Our findings indicate the positive clinical outcomes in patients with low RBH associated with the modified internal sinus elevation procedure.

Research hotspots and trends of microRNA in periodontology and dental implantology: a bibliometric analysis.

BACKGROUND: Periodontal disease is a leading cause of tooth loss, and microRNA (miRNA) has been shown to regulate various biological processes. This study aimed to quantitatively analyze the literature related to miRNA in periodontology and dental implantology and summarize the research hotspots and trends in this field. METHODS: Literature records from 1985 to 2020 were obtained from the Web of Science Core Collection database. After manual selection, the data was used for cooperative network analysis, keyword co-occurrence analysis, and reference co-citation analysis and visualized by CiteSpace. RESULTS: A total of 287 papers were analyzed between 2007 and 2020, and more than 95% of them were published in the past decade. The largest number of publications were from China, followed by the USA and Japan. The direct cooperation among the productive institutions was not close. At present, most of the research belongs to the discipline of dentistry, oral surgery, cell biology, and molecular biology. Literature clusters generated by reference co-citation analysis and keyword co-occurrence network showed that previous studies mainly focused on four hotspots: periodontal ligament stem cells (PDLSCs), the pathological process of periodontitis, osteogenic differentiation/bone regeneration, and the competing endogenous RNA (ceRNA) network. CONCLUSIONS: The therapeutic potential of miRNA in promoting bone formation and how the ceRNA network contributes to miRNA regulation at a deeper level have become the two main research trends of this field.

A meta-analysis and multisite time-series analysis of the differential toxicity of major fine particulate matter constituents.

Health risk assessments of particulate matter less than 2.5 µm in diameter (PM(2.5)) often assume that all constituents of PM(2.5) are equally toxic. While investigators in previous epidemiologic studies have evaluated health risks from various PM(2.5) constituents, few have conducted the analyses needed to directly inform risk assessments. In this study, the authors performed a literature review and conducted a multisite time-series analysis of hospital admissions and exposure to PM(2.5) constituents (elemental carbon, organic carbon matter, sulfate, and nitrate) in a population of 12 million US Medicare enrollees for the period 2000-2008. The literature review illustrated a general lack of multiconstituent models or insight about probabilities of differential impacts per unit of concentration change. Consistent with previous results, the multisite time-series analysis found statistically significant associations between short-term changes in elemental carbon and cardiovascular hospital admissions. Posterior probabilities from multiconstituent models provided evidence that some individual constituents were more toxic than others, and posterior parameter estimates coupled with correlations among these estimates provided necessary information for risk assessment. Ratios of constituent toxicities, commonly used in risk assessment to describe differential toxicity, were extremely uncertain for all comparisons. These analyses emphasize the subtlety of the statistical techniques and epidemiologic studies necessary to inform risk assessments of particle constituents.