BackgroundOrthodontic treatment can result in root resorption (RR). Traditional two-dimensional (2D) data exhibit magnification, deformation and positioning problems. Cone beam computed tomography (CBCT) contains more accurate three-dimensional (3D) information. This study identified and qualified the extent and location of root resorption using cone beam computed tomography (CBCT) after comprehensive orthodontic treatment.MethodsStudies comparing the RR before and after comprehensive orthodontic treatment using CBCT were identified using electronic searches of databases, including Cochrane, PubMed, EMBASE, China National Knowledge Infrastructure (CNKI) and Web of Science, and manual searches in relevant journals and the reference lists of the included studies until Oct 25, 2017. The extraction of data and the risk of bias evaluation were conducted by two investigators independently. The methodological quality of the included studies was assessed using the methodological index for non-randomized studies (MINORS). Studies that reported the length and volume of teeth were used for quantitative analyses.ResultsTwelve studies were included in the meta-analysis. The length of all teeth after intervention was significantly shorter than that before treatment (MD = 0.80, 95% CI 0.56, 1.03, P < 0.00001). The sequence of RR from heaviest to lightest was maxillary lateral incisors, maxillary central incisors, mandibular anterior teeth, and maxillary canines. Studies were divided into two subgroups based on the use of tooth extraction. Root shortening after treatment was observed in both groups, and extraction caused more root resorption than was observed in the non-extraction group.ConclusionsThere were different degrees of root resorption after orthodontics, but it was clinically acceptable. Root resorption established in CBCT research was less serious and more accurate than that observed in the two-dimensional research. Current evidence suggests that root length and volume were reduced after orthodontic treatment. The order of the amount of RR was maxillary lateral incisors, maxillary central incisors and mandibular anterior teeth. Most of the articles were complicated by different confounding factors. Therefore, more high-quality clinical trials are needed to determine the risk factors of root resorption and optimal protocols for treatment and to draw more reliable conclusions.

The objective of this study was to assess the effects of omega-3 fatty acid supplementation on various kidney transplantrelated outcomes. A systematic review and meta-analysis was performed of published randomized, controlled trials (RCT). There were 16 kidney transplant RCT with a total of 812 patients. All trials evaluated fish oil with dosages that ranged from 1.2 to 5.4 g/d. No consistent benefits were observed for any outcome with the exception of a modest benefit on triglycerides. A meta-analysis of rejection episodes found no significant benefit on either early (<6 mo posttransplantation) or late episodes. The overall relative risk of having at least one rejection episode in those who received fish oil was 0.91 (95% confidence interval 0.74 to 1.10) in four studies with a follow-up of 1 yr. A meta-analysis of eight RCT of graft survival found no significant benefit (relative risk 1.00, 95% confidence interval 0.96 to 1.05). The available data (mostly derived from older studies with important methodologic limitations) do not demonstrate a consistent, clinically important benefit of fish oil in kidney transplantation.

M andibular or maxillary continuity defects due to tumor resection, traumatic injuries, severe atrophy, or congenital anomalies can lead to significant facial deformity; altered oral function affecting mastication, speech, swallowing, and/or saliva retention; and subsequent psychologic problems. Aimed to achieve restoration of function and esthetics, oral rehabilitation of patients with bony defects of the jaws remains an important and challenging problem. 1,2 Free vascularized bone flaps have become a reliable procedure in the reconstruction of jaws and the adjacent soft tissue during the last few decades, especially for cases with large and complex defects. 3,4 Survival rates of 92% or higher for free vascularized bone flaps for the reconstruction of the jaws have been reported. 3-5 On the other hand, dental restoration is most important for function and esthetics after jaw resection. 6 Conventional prostheses are often difficult or unsuitable for rehabilitation of masticatory function because of the abnormal condition of hard and soft tissues postreconstruction. Placement of implants in reconstructed jaws permits fabrication of dental prostheses with improved stability and retention, 7-9 which facilitates the support of soft tissues and provides a stable platform for mastication and speech. 1 Rehabilitation of oral function and esthetics has been shown to be achievable by use of vascularized free flaps with the placement of endosseous implants. 2,3

The tail dependence of multivariate distributions is frequently studied via the tool of copulas. This paper develops a general method, which is based on multivariate regular variation, to evaluate the tail dependence of heavy-tailed scale mixtures of multivariate distributions, whose copulas are not explicitly accessible. Tractable formulas for tail dependence parameters are derived, and a sufficient condition under which the parameters are monotone with respect to the heavy-tail index is obtained. The multivariate elliptical distributions are discussed to illustrate the results.

Implantanchorage continues to receive much attention as an important orthodontic anchorage. Since the development of orthodontic implants, the scope of applications has continued to increase. Although multiple reviews detailing implants have been published, no comprehensive evaluations have been performed. Thus, the purpose of this study was to comprehensively evaluate the effects of implants based on data published in review articles.An electronic search of the Cochrane Library, Medline, Embase, Ebsco and Sicencedirect for reviews with “orthodontic” and “systematic review or meta analysis” in the title, abstract, keywords, or full text was performed. A subsequent manual search was then performed to identify reviews concerning orthodontic implants. A manual search of the orthodontic journals American Journal of Orthodontics and Dentofacial Orthopedics (AJODO), European Journal of Orthodontics (EJO), and Angle Othodontist was also performed. Such systematic reviews that evaluated the efficacy and safety of orthodontic implants were used to indicate success rates and molar movements.A total of 23 reviews were included in the analysis. The quality of each review was assessed using a measurement tool for Assessment of Multiple Systematic Reviews (AMSTAR), and the review chosen to summarize outcomes had a quality score of >6. Most reviews were less than moderate quality. Success rates of implants ranged in a broad scope, and movement of the maxillary first molar was superior with implants compared with traditional anchorage.

The tail dependence of multivariate distributions is frequently studied via the tool of copulas. This paper develops a general method, which is based on multivariate regular variation, to evaluate the tail dependence of heavy-tailed scale mixtures of multivariate distributions, whose copulas are not explicitly accessible. Tractable formulas for tail dependence parameters are derived, and a sufficient condition under which the parameters are monotone with respect to the heavy-tail index is obtained. The multivariate elliptical distributions are discussed to illustrate the results.

Objective To investigate the correlations between objective measurements and subjective evaluations of post-treatment facial attractiveness. Methods Ten orthodontists rated the subjective visual analog scale (VAS) scores of the facial profiles of 95 patients who had undergone orthodontic treatment. Post-treatment cephalograms and photographs were used. Eleven soft tissue measurements and eight maxillary incisor measurements were constructed and analyzed. Correlations between objective measurements and subjective VAS scores were evaluated using Pearson correlation and quadratic regression analysis. Results The VAS scores of different facial proportions were all correlated with the total VAS score. Among soft tissue measurements, the distances from the upper and lower lips to the E line, H angle, forehead inclination, distance from lower lip to the H line, and pogonion-menton angle were negatively correlated with the VAS scores. The Z angle, with a parabolic distribution, was also correlated with the VAS scores. Among maxillary incisor measurements, the distance from the maxillary incisors to the forehead’s anterior limit line and the angulation of the maxillary incisors to the APo line were negatively correlated with the VAS scores. Conclusions Several soft tissue and maxillary incisor position measurements were correlated with facial profile evaluation and therefore might be used to evaluate facial attractiveness.

Objective To examine whether facial reference lines could be used to evaluate the anteroposterior position of the maxillary incisors in patients that had undergone extraction treatment. Methods The study enrolled Angle Class I patients who had favourable facial profiles after extraction treatment. Superimposition of post-treatment lateral photographs and cephalograms were constructed and anatomical landmarks on the forehead were identified. Reference lines of the forehead’s anterior limit line (FALL) and the vertical line through the soft-tissue glabella (G line) were constructed. The distance between the maxillary incisors and the FALL and G line were measured. Regression analyses were performed between the maxillary incisor position and forehead inclination. Results Forty-one patients (31 females and 10 males) were included in the study. The mean ± SD distances of the facial-axis point of the maxillary incisors (FA)–FALL and FA–G line were 1.8 ± 1.9 mm and –2.4 ± 1.8 mm, respectively. The distance of the maxillary incisors to FALL and the relative position of the maxillary incisors were both significantly correlated with forehead inclination. Conclusions The mean position of the maxillary incisors in patients with extraction was approximately in the middle of the G line and the FALL. Correct maxillary incisor position was correlated with forehead inclination.