Strategic treatment for a patient with missing lateral incisor and first molar accompanied by posterior scissor bite and an impacted premolar.

Managing orthodontic treatment for adults with missing permanent teeth can be intricate, especially when dealing with a posterior scissor bite and an impacted tooth. This case report presents successful treatment of a female patient with dental and skeletal Class II malocclusion, high mandibular plane angle, missing maxillary left lateral incisor and mandibular right first molar, as well as right posterior scissor bite, and a deeply impacted mandibular left second premolar. In the maxilla, the right second molar and right lateral incisor were strategically extracted to eliminate the scissor bite and enhance frontal esthetic balance. In the mandible, the edentulous space caused by early loss of the first molar was successfully closed and the impacted second premolar was guided into its proper position after surgical exposure. Finally, symmetric frontal esthetics, well-aligned dentition with ideal intercuspation and an improved profile were achieved, which remained stable in the 17 month follow-up.

Effects of Dose and Injection Site on Gingival Smile Treatment with Botulinum Toxin Type A: A Prospective Study.

BACKGROUND: Botulinum toxin type A is an easy and efficacious treatment for gingival smile. However, the optimal dose and injection site are controversial. The authors compared the reduction in gingival exposure using two methods with different doses and injection sites. METHODS: In this prospective self-controlled study, healthy participants with gingival smile (anterior gingival exposure of >3 mm) underwent two treatment methods. First, participants received a single-point injection of 2 U of botulinum toxin type A per side (simplified method). After 8 months, the individualized method was performed with 2 to 5 U of botulinum toxin type A (total, 4 to 10 U), which was injected at one or two sites according to pretreatment severity. Data were collected at baseline and at 4, 12, and 32 weeks of follow-up. RESULTS: Fifty-five participants were enrolled. Anterior gingival exposure and bilateral posterior gingival exposure were significantly reduced 4 and 12 weeks after botulinum toxin type A injection ( P ≤ 0.05) with both methods. These parameters returned to baseline by 32 weeks ( P > 0.05). Posttreatment anterior gingival exposure at 4 weeks and 12 weeks with the individualized method was significantly lower compared with the simplified method (both P ≤ 0.05). Patient satisfaction with the individualized method was preferred compared with the simplified method ( P ≤ 0.05). Few adverse events were observed with both methods without statistical significance. CONCLUSION: It is necessary to increase the injection dose and tailor the injection site according to the pretreatment severity of anterior gingival smile.

Effects of the multifunctional hormone leptin on orthodontic tooth movement in rats.

This study aims to investigate the effects of leptin, which is a multifunctional hormone, on orthodontic tooth movement (OTM) and the underlying mechanism. Sprague-Dawley rat OTM models were established and divided into two groups with the administration of vehicle or leptin respectively. Stereomicroscope and microcomputed tomography were used to evaluate the amount of OTM. TRAP staining, immunohistochemical and immunofluorescence staining were used to detect osteoclasts and relative protein expressions. After treated with compression force, human periodontal ligament cells (hPDLCs) were co-cultured with human peripheral blood mononuclear cells (hPBMCs) with the presence or absence of leptin. Small interfering RNA (siRNA) was transfected to knock down the leptin receptor (LepR). The mRNA expressions of the targeted genes were evaluated by quantitative real-time polymerase chain reaction. We found that leptin receptors were expressed on both rat periodontal ligament cells and hPDLCs. OTM was significantly attenuated in the leptin-treated group comparing to the control group. The number of osteoclasts was reduced in the periodontal ligament tissues in vivo and in vitro co-cultured system when treated with leptin. The expression of RANKL was inhibited by leptin administration either in vivo and in vitro. Leptin administration also inhibited the force-induced up-regulation of RANKL expression in hPDLCs, which was rescued by LepR siRNA transfection. The osteoclastogenesis was attenuated by leptin administration which was reversed by the LepR siRNA transfection. Taken together, leptin was able to attenuate OTM by inhibiting osteoclastogenesis which can be attributed to the reduced expression of RANKL in the periodontal ligament. Leptin may possess the potential for reinforcing anchorage clinically.

Acetylsalicylic acid rescues the immunomodulation of inflamed gingiva-derived mesenchymal stem cells via upregulating FasL in mice.

BACKGROUND: Gingiva-derived mesenchymal stem cells (GMSCs) obtained multipotent differentiation and immunomodulatory properties. However, collecting healthy gingival tissues may be challenging in the clinical situation. Thus, in our present study, we aim to evaluate whether the immunomodulatory capacity of gingiva-derived mesenchymal stem cells from inflamed gingival tissues (iGMSCs) is impaired and find a way to rescue their deficient properties. METHODS: We compared the immunomodulation capacity of GMSCs and iGMSCs using an in vitro co-culture system and a mouse colitis model. T cell apoptosis, T helper 17 (Th17), and regulatory T (Treg) cell differentiation were detected by flow cytometry analysis. RESULTS: We demonstrated that iGMSCs obtained a decreased immunomodulatory capacity compared with GMSCs. Acetylsalicylic acid (ASA) pretreatment was able to rescue iGMSCs' impaired immunomodulatory properties. Mechanistically, ASA was capable of upregulating the expression of Fas ligand (FasL) in iGMSCs, leading to an improvement in iGMSC-mediated T cell apoptosis and therapeutic efficacy in the treatment in colitis mice. CONCLUSIONS: This study indicates that the deficient immunomodulatory function of iGMSCs could be rescued by ASA pretreatment via upregulating of FasL in mice. This strategy might serve as a practical approach to rescue deficient MSC function for further therapeutic application.

Different sliding mechanics in space closure of lingual orthodontics: a translational study by three-dimensional finite element method.

Lingual orthodontics have become popular in modern society as they do not cause aesthetic impairment. From the translational medicine point of view, the use of biomechanical analysis to solve a clinical problem has rarely been reported. Here, we combined the clinical trial and 3-D finite element (FE) method to translate the clinical problem to the FE analysis and back to clinic. Twenty upper premolar extraction cases treated with customized lingual appliances were recruited in this study. Cephalometric films and cast records analysis showed that the "bowing effect", which is a major side effect in lingual orthodontics, occurred during the first treatment stage with single lingual cable retraction. In order to translate the problem to biomechanical research, we introduced the 3-D finite element (FE) model of a customized lingual orthodontic system. The 3-D FE model including the maxilla, periodontal ligament (PDL), and dentition was constructed from human computed tomography data. The tendency of tooth movements in three dimensions and stress distribution in the PDL were analyzed by different mechanical loading methods. 3-D FE analysis confirmed the "bowing effects" and unexpected tooth movements with application of single lingual retraction force. Interestingly, we found that applying forces on both buccal and lingual sides, called "double cable" mechanics, could prevent the "bowing effect". For the clinical trial, we applied the "double cable" force during space closure stage for 4 months, and confirmed "double cable" mechanics could correct and prevent the "bowing effect" clinically. Based on our results, both buccal and lingual forces should be used during space closure in lingual orthodontics to prevent and correct the "bowing effect". Moreover, the magnitude of buccal force should not be lower than the force on the lingual side.

Obesity attenuates force-induced tooth movement in mice with the elevation of leptin level: a preliminary translational study.

Increasing number of patients with high body-mass index (BMI) are encountered in the orthodontic clinic with the growing prevalence of obesity and overweight worldwide. Some clinical studies found that the rate of orthodontic tooth movement (OTM) in obese patients decreased. However, how obesity can impact OTM has not been determined yet. Here, we used the high-fat diet (HFD) induced obese mouse model to translate this clinical problem to the basic research, and back to exploring the potential clinical applications. C57BL/6J mice were fed with high-fat diet (HFD) for 5 weeks to induce obesity and orthodontic nickel-titanium springs were applied to the upper first molars to establish OTM model. The serum level of leptin was tested by ELISA. Mouse macrophage cell line RAW264.7 cells were used as osteoclast progenitor cells stimulated by sRANKL with the presence or absence of letpin in vitro. TRAP staining was used to detect osteoclasts. Leptin was administrated intraperitoneally in mice to determine whether it can affect OTM in vivo. In obese mice, we found that OTM was attenuated and the number of osteoclasts decreased with the elevated serum level of leptin. Mechanically, we confirmed that leptin inhibited osteoclastogenesis and osteoclast functional genes expression. To translate our findings back to potential applications, we then revealed the administration of leptin could decrease OTM in wild type mice along with the decreased number of TRAP-positive osteoclasts. Taken together, these results demonstrated that the elevated level of leptin in obese mice was able to inhibit osteoclastogenesis and decrease OTM. Administration of leptin could inhibit molar mesial movement and possessed the potential to be a clinical anchorage reinforcement method.

Bone regeneration in minipigs by intrafibrillarly-mineralized collagen loaded with autologous periodontal ligament stem cells.

Biomimetic intrafibrillarly-mineralized collagen (IMC) is a promising scaffold for bone regeneration because of its structural and functional similarity to natural bone. The objective of this study was to evaluate the bone regeneration potential of IMC loaded with autologous periodontal ligament stem cells (PDLSCs) in large bone defects in minipigs. A macroporous IMC with a bone-like subfibrillar nanostructure was fabricated using a biomimetic bottom-up approach. Non-healing full thickness defects were established on the cranial bone in minipigs, and IMC and hydroxyapatite (HA) scaffolds seeded with autologous PDLSCs were implanted into these defects. Computed tomographic imaging, histology staining, and atomic force microscopy were applied to evaluate to the quantity, micro/nano structures, and mechanical performance of the neo-bone after 12 weeks of implantation. Compared with HA, IMC showed superior regeneration properties characterized by the profuse deposition of new bony structures with a normal architecture and vascularization. Immunohistochemistry showed that the runt-related transcription factor 2 and transcription factor Osterix were highly expressed in the neo-bone formed by IMC. Furthermore, the nanostructure and nanomechanics of the neo-bone formed by IMC were similar to that of natural bone. This study provides strong evidence for the future clinical applications of the IMC-based bone grafts.

Caffeine may enhance orthodontic tooth movement through increasing osteoclastogenesis induced by periodontal ligament cells under compression.

OBJECTIVE: Caffeine is the kernel component of coffee and has multiple effects on bone metabolism. Here we aimed to investigate the effects of caffeine intake on orthodontic tooth movement (OTM). DESIGN: (1) In the in vivo study, two groups comprising 15 randomly assigned rats each underwent orthodontic treatment. One group ingested caffeine at 25mg/kg body weight per day and the other, plain water. After 3 weeks, the degree of tooth movement and effect on the periodontium were assessed. (2) In the in vitro study, we established a model mimicking the essential bioprocess of OTM, which contained a periodontal ligament tissue model (PDLtm), and a co-culture system of osteoblasts (OBs) and osteoclast precursors (pre-OCs). After being subjected to static compressive force with or without caffeine administration, the conditioned media from the PDLtm were used for the OB/pre-OC co-cultures to induce osteoclastogenesis. RESULTS: (1) In vivo, the caffeine group displayed a significantly greater rate of tooth movement than the control. The alveolar bone mineral density and bone volume fraction were similar between the two groups; however, immunohistochemical staining showed that the caffeine group had significantly more TRAP(+) osteoclasts and higher RANKL expression in the compressed periodontium. (2) In vitro, caffeine at 0.01mM significantly enhanced the compression-induced expression of RANKL and COX-2, as well as prostaglandin E2 production in the PDLtm. Furthermore, the "caffeine+compression"-conditioned media induced significantly more TRAP(+) OC formation when compared with compression alone. CONCLUSIONS: Daily intake of caffeine, at least at some specific dosage, may enhance OTM through increasing osteoclastogenesis.

Systematic review of hypertension clinical practice guidelines based on the burden of disease: a global perspective.

OBJECTIVE: To perform a systematic review for the development, geographical distribution, and subject classification of clinical practice guidelines (CPGs) for hypertension worldwide. METHODS: CPGs for the management of hypertension were identified through the searching of Ovid, EMbase, and Chinese electronic databases. Major guidelines websites such as NGC (National Guideline Clearinghouse), GIN (Guidelines International Network), NICE (National Institute for Health and Clinical Excellence) and CPGN (Clinical Practice Guideline Network), as well as Google Scholar were also screened for additional information. EndNote X3 and Excel 2007 were used for extracting and analyzing the data of included CPGs. RESULTS: A total of 375 hypertension CPGs were included, involving 6 continents, 33 countries, 4 regions, and 3 international organizations. The publication date ranged from the year of 1971 to 2012, with the number of CPGs increased year by year. The CPGs were mainly developed by North America, Europe, and Asia. Their subjects covered 3 categories and 11 sub-classes, which mainly focused on the management of adult hypertension (44.53%). CONCLUSION: The number of CPGs varies in regions, countries, and academic organizations, with the development process differently. The regional disparity between the number CPGs and burden of hypertension were observed. The CPGs made a point of the management of adult hypertension.

High and specialty-related musculoskeletal disorders afflict dental professionals even since early training years.

OBJECTIVE: To determine how early musculoskeletal disorders (MSDs) develop in dental professionals and to explore the potential differences among distinct dental specialties. MATERIAL AND METHODS: 271 dental postgraduates majoring in five dental specialties were recruited, i.e., orthodontics, prosthodontics, endodontics, periodontics and alveolar surgery. 254 age-matched non-dental postgraduates served as the control. The standardized Nordic questionnaire on MSDs and a self-report questionnaire regarding correlative factors (only for dental postgraduates) were answered through emails. Reliability of responses was assessed applying test-retest method. RESULTS: The intraclass correlation coefficient of participants' answers ranged from 0.89 to 0.96. Dental postgraduates had significantly higher prevalence of MSDs than the control group, especially at neck, upper back and lower back. In all dental specialties included, high prevalence of MSDs was reported at neck (47.5%-69.8%), shoulders (50.8%-65.1%), lower back (27.1%-51.2%) and upper back (25.6%-46.5%), with lower prevalence at elbows (5.1%-18.6%), hips (3.4%-16.3%) and ankles (5.1%-11.6%). Periodontics students reported the worst MSDs in most body regions except wrists and knees, which were more prevalent for prosthodontic and alveolar surgery students, respectively. Furthermore, year of clinical work, clinical hours per week and desk hours per week were found as risk factors for MSDs, whereas physical exercise and rest between patients as protective factors. CONCLUSIONS: High and specialty-related MSDs afflict dental professionals even since very early stage of careers. Prevention aimed at the specialty-related characteristics and the risk/protective factors revealed in this study should be introduced to dental personnel as early as possible.

Arginine-containing toothpastes for dentin hypersensitivity: systematic review and meta-analysis.

OBJECTIVE: Arginine-containing toothpastes are a promising new treatment for dentin hypersensitivity (DH), which afflicts a considerable number of patients. However, there have to date been only individual studies. We aim to present an overview of the clinical evidence in order to determine trends and establish firmer conclusions regarding the use of arginine-containing toothpastes for management of DH. METHOD AND MATERIALS: A protocol was developed based on the Cochrane Handbook for Systematic Reviews of Interventions (version 5.1.0), including: search strategy, selection criteria, data extraction, and risk of bias assessment. We searched electronic databases (up to October 2012) without language limitation, and reference lists of relevant papers for randomized controlled trials that assessed the efficacy of arginine-containing toothpastes for DH treatment. Data extraction and domain-based risk of bias assessment were independently performed by two reviewers. The meta-analysis was performed in STATA (version 12.0). The GRADE analysis was conducted in GRADE profiler (version 3.6). RESULTS: Fourteen randomized controlled studies with different risk of bias were included in the meta-analysis, all evaluated by tactile and air blast assessment. The mean differences and standard deviations for each treatment group were pooled for analysis using a random-effect model. We found that arginine-containing toothpastes had better overall effects in comparison with placebo toothpastes (P < .05), potassium salt-containing toothpastes (P < .05), and strontium-containing toothpastes (P < .05). The GRADE analysis showed that quality of the evidence was moderate when arginine-containing toothpastes were compared to placebo and potassium salt-containing toothpastes, and quality of the evidence was low with comparison to strontium-containing toothpastes. CONCLUSION: Current available clinical evidence suggests that arginine-containing toothpastes are associated with the reduction of DH compared to both placebo and positive control toothpastes. However, there are limitations to the current studies, and more well-designed trials are needed to confirm the efficacy.

High and specialty-related musculoskeletal disorders afflict dental professionals even since early training years

OBJECTIVE: To determine how early musculoskeletal disorders (MSDs) develop in dental professionals and to explore the potential differences among distinct dental specialties. MATERIAL AND METHODS: 271 dental postgraduates majoring in five dental specialties were recruited, i.e., orthodontics, prosthodontics, endodontics, periodontics and alveolar surgery. 254 age-matched non-dental postgraduates served as the control. The standardized Nordic questionnaire on MSDs and a self-report questionnaire regarding correlative factors (only for dental postgraduates) were answered through emails. Reliability of responses was assessed applying test-retest method. RESULTS: The intraclass correlation coefficient of participants' answers ranged from 0.89 to 0.96. Dental postgraduates had significantly higher prevalence of MSDs than the control group, especially at neck, upper back and lower back. In all dental specialties included, high prevalence of MSDs was reported at neck (47.5%-69.8%), shoulders (50.8%-65.1%), lower back (27.1%-51.2%) and upper back (25.6%-46.5%), with lower prevalence at elbows (5.1%-18.6%), hips (3.4%-16.3%) and ankles (5.1%-11.6%). Periodontics students reported the worst MSDs in most body regions except wrists and knees, which were more prevalent for prosthodontic and alveolar surgery students, respectively. Furthermore, year of clinical work, clinical hours per week and desk hours per week were found as risk factors for MSDs, whereas physical exercise and rest between patients as protective factors. CONCLUSIONS: High and specialty-related MSDs afflict dental professionals even since very early stage of careers. Prevention aimed at the specialty-related characteristics and the risk/protective factors revealed in this study should be introduced to dental personnel as early as possible. .