Learning disabilities in dental education: trends,management, and concerns in U.S. dental schools

The prevalence of learning disabilities (LD) in higher education has drawn significant attention at the undergraduate level. College freshmen reporting learning disabilities have increased significantly in the past twenty years. Although anecdotal evidence suggests an increase in the number of dental students with learning disabilities, nothing has been published regarding how dental education is affected by this general trend. The purpose of this study was to obtain information from U.S. dental school administrators regarding the incidence and prevalence of learning disabilities in dental education. We hypothesized that there has been an increase in diagnosed cases of learning disabilities in dental education. Following a pilot study to identify individuals responsible for working with students with learning disabilities in U.S. dental schools (response rate 91 percent, n = 49), a eighteen-item survey instrument was distributed to specific contact individuals (response rate 81 percent, n = 44). Mean cumulative incidence of diagnosed cases of learning disabilities was 0.3 percent; mean prevalence of identified diagnosed cases of LD 0.7 percent. Pearson analysis revealed a statistically significant weak positive correlation between mean prevalence and year, suggesting an increase in identified diagnosed cases of LD in U.S. dental schools over the past seven years (r = 0.24, p = 0.002). We conclude that the presence of learning disabilities in dental education is silent, pervasive, and deserves increased attention.     

用自适应血管边缘检测方法自动跟踪测量血管自律运动

为实现以视频速度实时测量，建立一条与血管轴向垂直且在血管径向覆盖血管边缘的测量线作为采样窗口。通过对该测量线光密度分布的分析得到一个可逐帧自适应光密度变化的动态阈值，根据血管边缘区域内光密度曲线的形态特征和管径动态变化的可能范围来判定微血管边缘。建立多项判定规则提高边缘测定的精度并跳过非边缘区以加快处理速度。为进一步提高这种边缘测定的可靠性，在原图像上叠加一个与被测血管边缘位置相一致的动态图形指示。实用结果发现：即使在微血管图像背景复杂和反差较弱的情况下，这种采用自适应阈值和多项判别规则的微血管边缘动态检测方法仍能完成对微血管自律运动的自动跟踪测量     

Scaling and Root Planing Treatment for Periodontitis to Reduce Preterm Birth and Low Birth Weight: A Systematic Review and Meta‐Analysis of Randomized Controlled Trials

Background: The aim of this study is to perform an updated systematic review and meta‐analysis of randomized controlled trials (RCTs) evaluating the efficacy of scaling and root planing (SRP) in reducing the preterm‐birth and low‐birth‐weight risks to analyze important subgroups and to further explore heterogeneity and bias risks in the pooled studies. Methods: The entire Cochrane Library was searched (from 1990 to September 2011), MEDLINE (from 1950 to September 2011), CINAHL (from 1980 to September 2011), University of Michigan School of Dentistry “Dentistry and Oral Sciences” database (from 1990 to September 2011), conference proceedings, and the ClinicalTrials.gov database. Authors were contacted when clarification was needed. Selection criteria included the following: 1) RCTs that reported preterm‐birth risk (<37 weeks) outcomes, 2) compared SRP treatment to either placebo or no treatment in pregnant patients with periodontitis, and 3) had a probing depth >4 mm or clinical attachment loss >2 mm for ≥1 site. Reviewers independently extracted data from each included study using a standardized, piloted form and assessed quality using a risk‐of‐bias tool modeled after Cochrane, and discrepancies were resolved. A random‐effects model was used to calculate relative risks and 95% confidence intervals (CIs) for pooled data. For subgroup analysis with heterogeneity <50%, a fixed‐effects model was used. Results: After abstract review, 12 studies were identified by the search, and 11 were included in the main meta‐analysis (preterm birth <37 weeks). Overall quality and design of included studies was fair or good. For the main meta‐analysis, results ranged from risk ratio with periodontal treatment 0.14 (95% CI = 0.01, 2.55) to 1.24 (95% CI = 0.93, 1.67) for an overall risk ratio of 0.81 (95% CI = 0.64, 1.02). When analyzed separately by subgroup for excess prematurity risk, the high‐risk group (overall prematurity of 22.2% to 62.8%) showed combined risk ratios of 0.66 (95% CI = 0.54, 0.80). Remaining studies (overall prematurity of 4.0% to 10.4%) showed combined risk ratio of 0.97 (95% CI = 0.75, 1.24). Conclusions: This systematic review and meta‐analysis indicates statistically significant effect in reducing risk of preterm birth for SRP in pregnant women with periodontitis for groups with high risks of preterm birth only. Future research should attempt to confirm these findings and further define groups in which risk reduction may be effective.     

Factors associated with dental implant survival: a 4-year retrospective analysis

Background: Dental implants are a predictable treatment option for replacing missing teeth and have strong survival and success outcomes. However, previous research showed a wide array of potential risk factors that may have contributed to dental implant failures. The objectives of this study are to study if implant survival rates were affected by known risk factors and risk indicators that may have contributed to implant failures. The secondary outcome measures were whether the level of expertise of the periodontal residents affected success rates and how the rate of implant success at the Harvard School of Dental Medicine (HSDM) compared to published standards. Methods: A retrospective chart review of patients at the HSDM who had one of two types of rough‐surface implants (group A or B) placed by periodontology residents from 2003 to 2006 was performed. Demographic, health, and implant data were collected and analyzed by multimodel analyses to determine failure rates and any factors that may have increased the likelihood of an implant failure. Results: The study cohort included 341 dental implants. The odds ratio for an implant failure was most clearly elevated for diabetes (2.59 implant surface group B (7.84), and male groups (4.01). There was no significant difference regarding the resident experience. The success rate for HSDM periodontology residents was 96.48% during the 4‐year study period. Conclusions: This study demonstrates that implant success rates at HSDM fell within accepted published standards, confirmed previously identified risk factors for a failure, and potentially suggested that other acknowledged risk factors could be controlled for. Furthermore, the level of experience of the periodontology resident did not have an impact on survival outcomes.     

Identification and regulation of tissue plasminogen activator activity in rat cumulus-oocyte complexes

Plasminogen activators convert plasminogen into plasmin, a serine protease that initiates extracellular proteolysis. Two types of plasminogen activator activities have recently been demonstrated in granulosa cells, and the proteolysis-inducing enzymes are believed to be involved in ovulation. However, little attention has been paid to the presence of these enzymes in oocytes. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by a fibrin overlay technique, we studied plasminogen activator activity in oocytes. Denuded oocytes collected from ovaries of hypophysectomized, estrogen-treated immature rats contained a tissue-type plasminogen activator (tPA), but not urokinase (uPA). In contrast, oocyte-free granulosa cells in these preantral follicles contained uPA, but not tPA. The tPA activity found in oocytes was plasminogen-dependent; incubation with increasing numbers (25-200) of denuded oocytes resulted in a dose-dependent increase in fibrinolysis only in the presence of plasminogen. Cellular localization of tPA was studied in the preantral follicles using an immuno-cytochemical method. Positive tPA staining was detected in the cytoplasm, but not in the germinal vesicle or zona pellucida of the oocytes. Furthermore, analysis using a reverse fibrin-overlay method did not reveal the presence of a plasminogen activator inhibitor. Culturing of denuded oocytes for 24 h increased the cellular content of tPA, but the enzyme activity was not further enhanced by treatment with FSH or forskolin. Also, no tPA activity was detected in the medium. We further studied plasminogen activator activities in the cumulus-oocyte complexes. Although only tPA activity was detected in freshly obtained cumulus-oocyte complexes, incubation for 24 h increased both tPA and uPA activity. Furthermore, tPA, but not uPA, activity was stimulated by treatment with FSH or forskolin. This was accompanied by the secretion of tPA into the medium. The identity of tPA and uPA in the cumulus-oocyte complexes was further confirmed by immunoprecipitation with specific antibodies. Isolation of denuded oocytes and cumulus cells after hormonal stimulation of the cumulus-oocyte complexes suggested that tPA activity was stimulated in both cell types and that the cumulus cells may mediate the action of FSH and forskolin on oocytes. In conclusion, the detection and regulation of tPA activity in cumulus-oocyte complexes suggest possible involvement of this enzyme in ovulation or the process of cumulus cell expansion and dispersion. Changes in oocyte tPA content may also serve as an indicator of oocyte development.     

Using Evidence-Based Dentistry in the Clinical Management of Combined Periodontal Conditions

Objective

This report proposes a framework to integrate evidence-based dentistry (EBD) in a systematic approach in the clinical management of a patient diagnosed with drug-induced gingival hyperplasia combined with generalized aggressive periodontitis.This report illustrates the case of a 37-year-old female who presented to the Department of Periodontology at Tufts University School of Dental Medicine with enlarged, tender, bleeding gums, and loose teeth combined with a history of uncontrolled hypertension treated with calcium channel blockers.

Association between students' dental admission test scores and performance on comprehensive clinical exams

This study examined the association between Dental Admission Test (DAT) scores and the comprehensive exams conducted at Harvard School of Dental Medicine. The authors hypothesized that students who scored high on the DAT would also perform well on the comprehensive examinations. Sixty-six students from the graduating classes of 2005 and 2006 were included. The outcome variable of interest was the final composite grade obtained by the students in the three comprehensive examinations. The main independent variable of interest was the individual component scores on the DAT. Multivariable logistic regression analysis using the maximum likelihood methods was used to examine the association between comprehensive exam grades and DAT scores. Effects of age, gender, and race/ethnicity were adjusted in the regression models. On the first comprehensive examination, seventeen students obtained an Honors grade, while thirteen did so on the second comprehensive examination and fifteen on the third comprehensive examination. None of the DAT component scores were significantly associated with Honors grades on the first comprehensive examination. On the second comprehensive examination, quantitative reasoning scores (OR=2.48, 95 percent CI=1.09-5.68, p=0.03) and total science scores (OR=14.17, 95 percent CI=1.89-106.80, p=0.01) were significantly associated with Honors grades. Reading comprehension score was associated with increased odds of obtaining Honors grade on the third comprehensive examination (OR=1.81, 95 percent CI=1.13-2.92, p=0.01). Students who scored well on the quantitative reasoning, total science, and reading comprehension sections of the DAT had higher odds of receiving an Honors grade on the second and third comprehensive examinations. These factors may be associated with the problem-solving/critical thinking components in the school's PBL curriculum.     

An evaluation of bioactive glass in the treatment of periodontal defects: a meta-analysis of randomized controlled clinical trials

Background: The regenerative surgical treatment of intrabony defects caused by periodontal disease has been examined in several systematic reviews and meta‐analyses. The use of bioactive glass (BG) as a graft material to treat intrabony defects has been reported, but all data have not been synthesized and compiled. Our objective was to systematically review the literature on the use of BG for the treatment of intrabony defects and to perform a meta‐analysis of its efficacy. Methods: A search of PubMed, EMBASE, and Cochrane Database of Systematic Reviews, as well as a manual search of recently published periodontology journals, were conducted to identify randomized controlled trials of the use of BG in the treatment of intrabony and furcation defects. Criteria included publication in English, follow‐up duration of ≥6 months, baseline and follow‐up measures of probing depth (PD) and clinical attachment levels (CAL) with 95% confidence intervals (CIs), and an appropriate control arm. Twenty‐five citations were identified, 15 of which were included in the final analysis. Data, including study methods and results, as well as CONSORT (Consolidated Standards of Reporting Trials) criteria, were extracted from eligible studies and cross‐checked by at least two reviewers. Results: Meta‐analyses of eligible studies were performed to ascertain summary effects for changes in PD and CAL among experimental and control groups, using the mean change plus standard deviation for each study. Pooled analyses showed that BG was superior to control for both measures: the mean (95% CIs) difference from baseline to follow‐up between BG and controls was 0.52 mm (0.27, 0.78, P <0.0001) in reduction for PD and 0.60 mm (0.18, 1.01, P = 0.005) in gain for CAL. Analyses of CAL revealed heterogeneity across studies (I² = 60.5%), although studies reporting PD measures were homogeneous (I² = 0.00%). CAL heterogeneity appeared secondary to active controls versus open flap debridement (OFD) alone and to defect‐type modifying BG treatment success. Per subgroup analyses, the benefit of BG over control treatment was highly significant only in studies comparing BG to OFD (P <0.0001), with mean difference change in CAL being 1.18 mm (95% CI = 0.74, 1.62 mm) between the BG and OFD group. Conclusion: Treatment of intrabony defects with BG imparts a significant improvement in both PD and CAL compared to both active controls and OFD.