Effect of over-the-counter whitening strips and toothpaste on shear bond strength of orthodontic brackets

To investigate: 1) the effects of over-the-counter white strip enamel bleaching and 2-Step whitening toothpaste application on the shear bond strength of orthodontic brackets at 24-hours and 7-days post-bleaching latent period; and 2) the correlation bet

Mechanical properties of the NiTi Memoria Leaf Spring Activated Expander (NiTi MLSAE) for maxillary transverse discrepancy correction : an in-vitro study

To determine the mechanical properties of the NiTi Memoria® Leaf Spring Activated Expander (NiTi MLSAE) in two forms, unaltered (unbent) and altered (bent) to mimic clinical use. This in-vitro pilot study was conducted using eight NiTi MLSAE expanders (American Tooth Industries, Oxnard, California) representing four force magnitudes: 10mm 500g, 10mm 900g, 6mm 450g and 6mm 900g models. Two experiments were performed: the first tested the expanders in their unbent form and the second tested them after they were bent by one experienced technician. All expanders were adapted to a standard three dimensional printed maxillary study model. A Dillion Quantrol 500N (110lbf) load cell and a custom-made fixturing apparatus was used to determine the amount of expansive forces delivered. Prior to testing, the ligation compressing the NiTi MLSAE leaves was cut to allow the appliances to expand to their original form. Emperor? (force) Software was used to measure the expansion forces. The average expansion forces generated by the expanders were: unaltered = 897.4g (8.8N) and bent = 877.0g (8.6N) for the 10mm 900g model, unaltered = 489.5g (4.8N) and bent = 479.3g (4.7N) for the 10mm 500g model, unaltered = 458.9g (4.5N) and bent = 438.5g (4.3N) for the 6mm 450g model, and unaltered = 805.6g (7.9N) and bent = 785.2g (7.7N) for the 6mm 900g model. Regardless of whether the expander was straight or bent, the forces generated by the 10mm 900g, 10mm 500g and 6mm 450g Ni-Ti MLSAEs correlated with the benchmark study conducted by the manufacturer. However, the forces generated by the 6mm 900g Ni-Ti MLSAE were less than the data published by the manufacturer. Binding was observed when the expanders were manipulated to mimic clinical use, and this may account for the reported lower expansion force

Relationship between mandibular symphysis dimensions and skeletal pattern in adults

Background: The knowledge of dimensions of the symphysis is important for morphological and orthodontic studies. This research evaluates the association between mandibular symphysis dimensions and anteroposterior and vertical skeletal patterns in adults. Materials and methods: This cross-sectional cephalometric study included 90 lateral cephalograms of untreated subjects presenting for orthodontic treatment. The inclusion criteria were adults with lateral cephalograms showing the symphyseal region and anterior cranial base. One investigator traced and analyzed all cephalograms. Symphyseal height, thickness, and ratio between height and thickness were measured in relation to seven anteroposterior and vertical skeletal measurements in females and males. Results: Symphyseal measurements were associated with SNAo (anteroposterior) in females and Gonial angle (vertical) in males. When analyzed by anteroposterior skeletal classification (ANBo), no significant differences in symphyseal dimensions were found. Multiple linear regression analyses showed that Gonion-Nerve (mm) and Gonial angle were significantly associated with symphyseal height. Gonion-Nerve (mm), basal bone width (mm), and alveolar bone height (mm) were associated with symphyseal thickness. Basal bone width (mm) and alveolar bone height (mm) were associated with symphyseal ratio. Conclusions: Symphyseal dimensions were significantly associated with vertical but not anteroposterior skeletal patterns. Future studies are warranted to evaluate the Gonion-nerve measurements concerning the symphysis in relation to vertical and anteroposterior skeletal patterns

Evaluating the effectiveness of a preclinical practice of tooth preparation using digital training system:A randomised controlled trial

Purpose: This study aimed to evaluate the effectiveness of preclinical training on ceramic crown preparation using digital training system compared with traditional training method.Materials and methods: A sample of 66 participating fourth-year undergraduate dental students were randomly assigned to one of two groups for ceramic crown preparation: experimental group as trained using digital method with Online Peer-Review System (OPRS) and Real-time Dental Training and Evaluation System (RDTES); control group as trained using traditional method with instructor demonstration and evaluation. At the completion of training periods, both groups performed the preparation of ceramic crown of upper left central incisor, which were blindly scored by the experienced instructors under the pre-defined assessment criteria. The results of both were compared using Student's t-test or Wilcoxon signed rank test. The level of significance was P &lt; .05. The questionnaires regarding the benefits or drawbacks of digital training system were answered by the students of experimental group.Results: Five of 15 items in the assessment outcome of the digital group were significantly better than the traditional group. The questionnaire results from the students of the experimental group indicated 96.97% of the students agreed or strongly agreed that using digital training system could better improve the practical ability than traditional method. The total scores of practical results were significantly positively correlated with the points of the questionnaires.Conclusion: The digital training system with OPRS and RDTES might be a good alternative to the traditional training method in the preclinical course of dental practice.</p

Evaluation of Faculty Mentoring Practices in Seven U.S. Dental Schools

The aim of this cross‐sectional study was to examine the faculty mentoring practices in seven dental schools in the U.S. A 34‐item survey was administered electronically to dental faculty members of all ranks, tracks, and job categories in seven dental schools using faculty listservs. Survey questions addressed current mentoring practices in which the faculty members were involved; their perceptions of those mentoring practices; their perceived characteristics of an ideal mentoring program, mentor, and mentee; perceived best practices; and respondents’ demographics. The survey was conducted from October 2017 to February 2018. A total of 154 surveys were completed (response rate 22%). Over 58% (90/154) of the respondents reported receiving no mentoring; 31.9% (49/154) said they received informal mentoring; and 9.7% (15/154) received formal mentoring. Of the 64 respondents who received mentoring, both formal and informal, 92.2% (59/64) were full‐time faculty, and 7.8% (5/64) were part‐time faculty (p=0.001). Approximately 39% of the respondents indicated that their mentoring program was not overseen by anyone and that participation was voluntary. The top three perceived benefits of mentoring were increased overall professional development, development of a career plan, and increased professional networks. The three most important characteristics of an ideal mentoring program for the respondents were a program based on the needs of the mentee, a mentor who has the desire to help the mentee, and a mentee who is eager to learn. The results of this study showed a very low level of formal or informal faculty mentoring programs in the dental schools surveyed. Future studies are needed to determine best practices and strategies to expand and enhance mentoring of faculty members

The Porphyromonas gingivalis/host interactome shows enrichment in GWASdb genes related to Alzheimer’s disease, diabetes and cardiovascular diseases

Periodontal disease is of established aetiology in which polymicrobial synergistic ecology has become dysbiotic under the influence of Porphyromonas gingivalis. Following breakdown of the host’s protective oral tissue barriers, P. gingivalis migrates to developing inflammatory pathologies that associate with Alzheimer’s disease (AD). Periodontal disease is a risk factor for cardiovascular disorders (CVD), type II diabetes mellitus (T2DM), AD and other chronic diseases, whilst T2DM exacerbates periodontitis. This study analysed the relationship between the P. gingivalis/host interactome and the genes identified in genome-wide association studies (GWAS) for the aforementioned conditions using data from GWASdb (P<1E-03) and, in some cases, from the NCBI/EBI GWAS database (P< 1E-05). Gene expression data from periodontitis or P. gingivalis microarray was compared to microarray datasets from the AD hippocampus and/or from carotid artery plaques. The results demonstrated that the host genes of the P. gingivalis interactome were significantly enriched in genes deposited in GWASdb genes related to cognitive disorders, AD and dementia, and its co-morbid conditions T2DM, obesity, and CVD. The P. gingivalis/host interactome was also enriched in GWAS genes from the more stringent NCBI-EBI database for AD, atherosclerosis and T2DM. The misregulated genes in periodontitis tissue or P. gingivalis infected macrophages also matched those in the AD hippocampus or atherosclerotic plaques. Together, these data suggest important gene/environment interactions between P. gingivalis and susceptibility genes or gene expression changes in conditions where periodontal disease is a contributory factor