Association between volatile organic compounds exposure and periodontitis: A representative cross-sectional study.

AIM: Periodontitis is one of the most common oral diseases and a major cause of tooth loss in adults. Environmental pollution is closely associated with the prevalence of periodontitis. However, few studies have focused on the association between volatile organic compounds (VOCs) and periodontitis. This cross-sectional study aims to examine whether exposure to VOCs is associated with periodontitis, based on data from the National Health and Nutrition Examination Survey (NHANES, 2011-2014). MATERIALS AND METHODS: We analysed data on blood VOC levels, periodontitis and related covariates from 2772 participants of the NHANES. The association between the blood VOCs and periodontitis was analysed using weighted logistic regression analysis, the restricted cubic spline (RCS) model and the weighted quantile sum (WQS) regression model. Interaction tests and mediation analysis were also conducted. RESULTS: After adjusting for covariates, for each natural constant-fold increase in 1,4-dichlorobenzene, the odds of having periodontitis increased by 16% (odds ratio = 1.16; 95% confidence interval: 1.08-1.24, p < .001). WQS regression model indicated that 1,4-dichlorobenzene contributed the most to the association between VOC co-exposure and periodontitis. Mediation analysis further revealed that total bilirubin levels mediated the association between 1,4-dichlorobenzene and the prevalence of periodontitis, accounting for 4.32%. In addition, the positive association between o-xylene and periodontitis was more pronounced in the <65-year-old group. CONCLUSIONS: This study has provided relatively little evidence to demonstrate a specific link between VOCs and periodontitis. Nonetheless, exposure to VOCs remains a non-negligible public health concern, and further research is required to investigate the association and potential mechanisms of action between VOCs and periodontitis.

Application of a modified osteotomy and positioning integrative template system (MOPITS) based on a truncatable reconstruction model in the precise mandibular reconstruction with fibula free flap: a pilot clinical study.

BACKGROUND: Mandibular defects can greatly affect patients' appearance and functionality. The preferred method to address this issue is reconstructive surgery using a fibular flap. The current personalized guide plate can improve the accuracy of osteotomy and reconstruction, but there are still some problems such as complex design process and time-consuming. Therefore, we modified the conventional template to serve the dual purpose of guiding the mandible and fibula osteotomy and facilitating the placement of the pre-bent titanium. METHODS: The surgery was simulated preoperatively using Computer-Aided Design (CAD) technology. The template and truncatable reconstruction model were produced in the laboratory using 3D printing. After pre-bending the titanium plate according to the contour, the reconstruction model was truncated and the screw trajectory was transferred to form a modified osteotomy and positioning integrative template system (MOPITS). Next, the patient underwent a composite template-guided vascularized fibula flap reconstruction of the mandible. All cases were reviewed for the total operative time and accuracy of surgery. RESULTS: The procedures involved 2-4 fibular segments in 15 patients, averaging 3 fibular segments per procedure. The osteotomy error is 1.01 ± 1.02 mm, while the reconstruction angular error is 1.85 ± 1.69°. The preoperative and postoperative data were compared, and both p > 0.05. During the same operation, implant placement was performed on four patients, with an average operative time of 487.25 ± 60.84 min. The remaining malignant tumor patients had an average operative time of 397.18 ± 73.09 min. The average postoperative hospital stay was 12.95 ± 3.29 days. CONCLUSIONS: This study demonstrates the effectiveness of MOPITS in facilitating precise preoperative planning and intraoperative execution of fibula flap reconstruction. MOPITS represents a promising and reliable tool for reconstructive surgery, particularly for inexperienced surgeons navigating the challenges of mandible defect reconstruction.

Associations of low level of fluoride exposure with dental fluorosis among U.S. children and adolescents, NHANES 2015-2016.

Drinking water fluoridation was a mid-twentieth century innovation based on the medical hypothesis that consuming low doses of fluoride at the teeth forming years provided protection against dental decays. Numerous studies showed that high level exposure to fluoride could cause dental and skeleton fluorosis. However, there was limited study focusing on the fluorosis effect of low levels of exposure to fluoride. Therefore, our study aimed to examine whether the low level of fluoride exposure (measured in blood plasma and household tap water) was associated with the risk of dental fluorosis based on data of the National Health and Nutrition Examination Survey (NHANES) 2015-2016. We analyzed data in 2098 children and adolescents who had Dean's Index scores, and water and plasma fluoride measures. The Dean's Index score was measured by calibrated dental examiners using the modified Dean's fluorosis classification system. Fluoride was measured in plasma and household tap water. In this study, we found that the rate of fluoride concentration in water above the recommended level of 0.7 mg/L was 25%, but the prevalence of dental fluorosis was 70%. Binary logistic regression adjusted for covariates showed that higher water fluoride concentrations (0.31-0.50, 0.51-0.70, > 0.70 compared 0.00-0.30) were associated with higher odds of dental fluorosis (OR = 1.48, 95% CI: 1.13-1.96, p = 0.005; OR = 1.92, 95% CI: 1.44-2.58, p < 0.001, and OR = 2.30, 95% CI: 1.75-3.07, p < 0.001, respectively). The pattern of regression between plasma fluoride and dental fluorosis was similar. Inclusion, our study showed that even low level of water or plasma fluoride exposure was associated with increased the risk of dental fluorosis. The safety of public health approach of drinking water fluoridation for global dental caries reduction are urgently needed further research.

Effects of laser debonding treatment on the optical and mechanical properties of all-ceramic restorations.

The objective of this study was to evaluate how erbium-doped yttrium aluminium garnet (Er:YAG) laser debonding treatment affects the optical and mechanical properties of dental ceramics. In total, 120 rectangular (22*5*1.2 mm) IPS E.max Press specimens were fabricated and divided into 4 groups: the control group, 3 W laser group, 4 W laser group, and 5 W laser group. For each group, 10 specimens were used for the colour test (colour difference (△E) and transparency parameter (TP)), 10 specimens were used for the flexural strength test, and 10 were used for the Vickers hardness test. One random sample from each colour test specimens was observed by scanning electron microscopy (SEM). The L*, a*, b*, △E, TP, flexural strength, and Vickers hardness values were measured and calculated. According to the Kruskal-Wallis test, the L*, a*, and b* values showed no significant variations (P > 0.05), except for the b* value in the 5 W laser group (P < 0.05). The △E, TP, flexural strength, and Vickers hardness values were analysed by one-way analysis of variance (ANOVA). The 5 W laser group exhibited a higher △E value, which exceeded the perceptible threshold and significantly lower TP values than the other groups (P < 0.05). The mean flexural strength and Vickers hardness values after Er:YAG laser debonding revealed no significant changes (P > 0.05). Microcracks were detected during the SEM analysis of the 5 W laser group. Er:YAG laser debonding treatment did not affect the mechanical properties, but changed the optical properties of dental ceramics.

The Early Adhesion Effects of Human Gingival Fibroblasts on Bovine Serum Albumin Loaded Hydrogenated Titanium Nanotube Surface.

The soft tissue sealing at the transmucal portion of implants is vital for the long-term stability of implants. Hydrogenated titanium nanotubes (H2-TNTs) as implant surface treatments were proved to promote the adhesion of human gingival fibroblasts (HGFs) and have broad usage as drug delivery systems. Bovine serum albumin (BSA) as the most abundant albumin in body fluid was crucial for cell adhesion and was demonstrated as a normal loading protein. As the first protein arriving on the surface of the implant, albumin plays an important role in initial adhesion of soft tissue cells, it is also a common carrier, transferring and loading different endogenous and exogenous substances, ions, drugs, and other small molecules. The aim of the present work was to investigate whether BSA-loaded H2-TNTs could promote the early adhesion of HGFs; H2-TNTs were obtained by hydrogenated anodized titanium dioxide nanotubes (TNTs) in thermal treatment, and BSA was loaded in the nanotubes by vacuum drying; our results showed that the superhydrophilicity of H2-TNTs is conducive to the loading of BSA. In both hydrogenated titanium nanotubes and non-hydrogenated titanium nanotubes, a high rate of release was observed over the first hour, followed by a period of slow and sustained release; however, BSA-loading inhibits the early adhesion of human gingival fibroblasts, and H2-TNTs has the best promoting effect on cell adhesion. With the release of BSA after 4 h, the inhibitory effect of BSA on cell adhesion was weakened.

Decompression-first or direct enucleation: The choice of treatment for medium-sized odontogenic jaw cysts.

BACKGROUND: The treatment of medium-sized odontogenic jaw cysts is inconsistent at present. Two main treatments, namely decompression and enucleation, are used overlappingly. This retrospective analysis aims to provide useful references for technique selection for future management of medium-sized odontogenic jaw cysts. METHODS: Odontogenic cysts with lesion sizes ranging 2-4 cm were included. The clinical and radiological data of the patients were reviewed. Decompression-first and direct enucleation treatments were the two main surgical techniques. The preoperative parameters and postoperative outcomes were compared between the two groups. RESULTS: Out of 69 patients included, 40 (58 %) were in the decompression group and 29 (42 %) in direct enucleation group. The logistic regression analysis of preoperative parameters demonstrated that the maximum lesion size and the chief surgeon's preference could affect the selection of surgical techniques for medium-sized cysts (P < 0.05). Receiver operating characteristic curve analyses demonstrated that a lesion size >2.5 cm was the best cutoff value for predicting a decompression selection. Most postoperative outcomes differed significantly between the two groups (P < 0.05). Lower-risk anesthesia, shorter hospitalization, tooth function protection, and fewer neurosensory impairments were decompression-favoring outcomes. However, more follow-up visits, more postoperative X-rays, and longer postoperative care were outcomes against decompression. The recurrence rate was low and did not differ significantly between the two groups (P > 0.05). CONCLUSIONS: There is no apparent preference for treating medium-sized jaw cysts. The maximum lesion size is a moderate-impact factor for treatment selection. A tendency to prefer decompression-first with larger lesion size was found in medium-sized jaw cysts. The advantages of teeth preservation and low neurosensory impairment of decompression were verified in the medium-size jaw cysts. The burden of postoperative care should be considered when selecting decompression.

Composite bioink incorporating cell-laden liver decellularized extracellular matrix for bioprinting of scaffolds for bone tissue engineering.

The field of bone tissue engineering (BTE) has witnessed a revolutionary breakthrough with the advent of three-dimensional (3D) bioprinting technology, which is considered an ideal choice for constructing scaffolds for bone regeneration. The key to realizing scaffold biofunctions is the selection and design of an appropriate bioink, and existing bioinks have significant limitations. In this study, a composite bioink based on natural polymers (gelatin and alginate) and liver decellularized extracellular matrix (LdECM) was developed and used to fabricate scaffolds for BTE using 3D bioprinting. Through in vitro studies, the concentration of LdECM incorporated into the bioink was optimized to achieve printability and stability and to improve the proliferation and osteogenic differentiation of loaded rat bone mesenchymal stem cells (rBMSCs). Furthermore, in vivo experiments were conducted using a Sprague Dawley rat model of critical-sized calvarial defects. The proposed rBMSC-laden LdECM-gelatin-alginate scaffold, bioprinted layer-by-layer, was implanted in the rat calvarial defect and the development of new bone growth was studied for four weeks. The findings showed that the proposed bioactive scaffolds facilitated angiogenesis and osteogenesis at the defect site. The findings of this study suggest that the developed rBMSC-laden LdECM-gelatin-alginate bioink has great potential for clinical translation and application in solving bone regeneration problems.

Long-term bone remodeling after definitive decompression for jaw cysts based on a three-dimensional analysis.

BACKGROUND: Decompression is an effective treatment for jaw cysts. Many studies have reported its effectiveness as a preliminary treatment followed by secondary enucleation. This study aimed to explore long-term bone remodeling after definitive decompression for jaw cysts based on a three-dimensional (3D) analysis. METHODS: This was a retrospective study. The clinical and radiological data of patients with jaw cysts who underwent decompression and were followed up for two years or more at Peking Union Medical College Hospital between January 2015 and December 2020 were reviewed. The 3D radiological data before and after decompression were analyzed to study the long-term reduction in cysts, especially after one year of decompression. RESULTS: A total of 17 patients with jaw cysts were included in this study. The radiological data showed a mean reduction rate of 78% one year after decompression. At the final examination, which was 36.1 months after decompression on average, the mean reduction rate was 86%. The unossified lesions could still ossify slowly after one year of decompression. The recurrence rate was 5.9% (1/17). CONCLUSIONS: Bone remodeling continued for a long time after decompression. Definitive decompression could be an option for most patients with jaw cysts. Long-term follow-up is required.

Evaluation of Er:YAG laser energy transmitted through novel dental zirconia ceramics.

Erbium:yttrium-aluminum-garnet (Er:YAG) laser debonding is a promising removal method in prosthodontics. This study aimed to assess Er:YAG laser energy transmission through novel zirconia ceramics. Five types of ceramic samples: lithium disilicate ceramic (LDC), self-glazed zirconia (SGZ), 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP), 4Y-TZP and 5Y-TZP with 5 thicknesses (0.5, 1.0, 1.5, 2.0, 2.5 mm) and 2 shades (A1, A3), 50 specimens total, were made. Fourier transformation infrared absorption spectra were obtained for each ceramic type, and Er:YAG laser energy transmission tests were conducted for each specimen. The novel zirconia ceramic (SGZ, 4Y-TZP, 5Y-TZP) transmission ranged from 40%-60%. The transmitted laser energy decreased with increasing ceramic thickness, and the differences between different shades were significant (p<0.05). The novel zirconias had a higher translucency than 3Y-TZP at any given thickness and shade, and when the thickness was >1.5 mm, the novel zirconias had a higher translucency than LDC.

Giant calcifying epithelial odontogenic tumor after I-125 seed implantation: A case report.

Calcifying Epithelial Odontogenic Tumor (CEOT), also known as Pindborg tumor, is a rare odontogenic benign tumor. It was first reported by Thoma and Goldman in 1946 and defined as an independent tumor by Pindborg in 1957. Herein, we reported a CEOT case involving most of the mandible after I-125 implantation in a 53-year-old man. We cooperated with governmental and hospital departments to resect the tumors, reconstruct the mandible with a fibular flap graft, and properly dispose of the radioactive particles.

Effectiveness of case-based learning in Chinese dental education: a systematic review and meta-analysis.

OBJECTIVE: The application of case-based learning (CBL) pedagogy has been emerging as an improved and more practical learning method across the Chinese dental education system. This article provides a critical overview of CBL pedagogy and further assesses the effectiveness of this teaching model in Chinese dental education. DESIGN: A systematic review and meta-analysis. METHODS: Studies published up to December 2019 were searched in the following electronic databases: China National Knowledge Infrastructure, China Science Periodical Database, Chinese Biomedical documental database, Wanfang data, PubMed, EMBASE and Cochrane Central Register of Control Trials. All randomised controlled trials (RCTs) that compared the effectiveness of the CBL teaching model and the traditional lecture-based learning (LBL) model in all dental disciplines were included. The assessment of methodological quality was based on the guidelines described in the Cochrane Handbook for Systematic Reviews, and the meta-analysis was performed using the software RevMan V.5.3 RESULTS: A total of 30 RCTs were finally included, with a total sample size of 2356 dental students. The CBL pedagogy significantly increased knowledge scores (standardised mean difference (SMD)=1.58, 95% CI: 0.95 to 2.20, p<0.0001), skill scores (SMD=1.22, 95% CI: 0.34 to 2.11, p<0.0001), comprehensive ability scores (SMD=1.91, 95% CI: 1.74 to 4.07, p<0.0001) and teaching satisfaction (risk ratio=1.38; 95% CI: 1.15 to 1.65; p=0.01) compared with the LBL teaching model among the dental students. Additionally, a subgroup analysis showed significant differences in the effects of CBL on knowledge scores, skill scores and comprehensive ability scores when comparing theoretical and practical courses. CONCLUSIONS: The meta-analysis and systematic review of the eligible literature showed that the CBL pedagogy in Chinese dental education is an effective way to increase knowledge scores, skill scores, comprehensive ability scores and teaching satisfaction. Successful adaptation of this teaching model could solve the scarcity of highly skilled and professional dentists in dental schools and hospitals across China.

Evaluation of the degradation, biocompatibility and osteogenesis behavior of lithium-doped calcium polyphosphate for bone tissue engineering.

BACKGROUND: Calcium polyphosphate (CPP) is a commonly used biomaterial in bone tissue engineering, but CPP is insufficient in osteoinduction. This study aimed to fabricate lithium doped CPP (LiCPP) scaffolds and assess their characterization, degradation, biocompatibility and osteogenesis behavior for bone tissue engineering. METHODS: The novel scaffold was characterized by XRD, FTIR and SEM. The porosity, cell mediated degradation behavior and mechanical properties were also investigated. Meanwhile, cell proliferation activity and adhesion in vitro was exploited. Finally, osteogenesis the LiCPP scaffolds in vitro and in vivo was researched. RESULTS: The outcomes revealed that low-content Li doping had no significant influence on the structure of CPP. The results of cells mediated degradation experiments from the weight loss and the release of ions indicated that Li doped CPP improved biological degradation. The compressive strength of CPP with 66% porosity was improved to 7 MPa. Cells proliferation experiment and adhesion experiment demonstrated 2.0%LiCPP scaffold was most beneficial to cell growth and attachment. Furthermore, Li doped CPP up-regulated Wnt signal pathway when co-cultured with MG63 and increased osteogenic marker ALP expression and calcium phosphate deposition in vitro. At the same time, new bone formation in vivo was also enhanced by using LiCPP scaffolds and the 2.0%LiCPP scaffolds obtained best osteogenesis outcomes. CONCLUSION: The results obtained in our study suggest that 2.0%LiCPP scaffold could benefit from improving the osteogenesis behavior and is a promising biomaterial for bone repairing applications.