Nevin Manimala

J Contemp Dent Pract. 2020 Nov 1;21(11):1233-1237.

ABSTRACT

AIM AND OBJECTIVE: The present study aimed to assess the formation of microcracks in root dentin post-instrumentation with nickel-titanium (NiTi) hand and rotary file system.

MATERIALS AND METHODS: Totally, 80 freshly extracted mandibular premolar teeth with single roots were chosen for this study. Access opening was performed and #10 K-file was used to attain patency of canal. All specimens were divided into four groups (each group having 20 specimens), i.e., Group I: Unprepared, Group II: NiTi hand K-files, Group III: Self-adjusting file, and Group IV: XP-Shaper single file. Complete irrigation of all the canals was performed after instrumentation. All roots were cut horizontally at three levels [apical third (3 mm), middle third (6 mm), and cervical third (9 mm)] from the apex with diamond disc. A stereomicroscope was used to view the sections under 20× magnification.

RESULTS: Self-adjusting file showed least number of defects with a percentage of 75% followed by XP-Shaper and NiTi hand K-files with a values of 65 and 60%, respectively. Use of hand K-files resulted in greater number of incomplete cracks (30%) and use of XP-Shaper demonstrated greater number of craze lines (15%). A statistically significant difference was found between the experimental groups in the formation of dentinal defects of root at apical third (3 mm) (p < 0.031) and middle third (6 mm) (p < 0.001), whereas the sections at cervical third (9 mm) did not show any statistically significant difference (p > 0.312).

CONCLUSION: The present study concluded that the self-adjusting file system gives promising better results in cleaning ability with minimal incidence of radicular dentin microcracks than XP-Shaper and NiTi hand K-files system.

CLINICAL SIGNIFICANCE: The root dentin may unavoidably get damaged during instrumentation resulting in the formation of dentinal cracks and tiny complicated fractures, thus leading to endodontic failures. Various factors cause dentinal cracks, but the flexibility of file due to heat treatment, kinematics of the file, and the basic architecture of the file are the most significant ones. Self-adjusting file system represented satisfactory results with minimal microcracks defects.

PMID:33850068

J Contemp Dent Pract. 2020 Nov 1;21(11):1201-1204.

ABSTRACT

AIM: This study aims to evaluate the difference in fracture resistance of the short fiber-reinforced composite (SFRC) thickness as intermediate layer of class II composite restoration.

MATERIALS AND METHODS: Thirty human maxillary premolars were selected and divided into three groups. In groups I, II, and III, class II cavities were prepared. Groups I and II were restored with 2 mm and 4 mm thickness of SRFC as intermediate layer. Group III as control group was restored with nanohybrid composite. Thermocycling procedure was performed manually 250 times. Fracture resistance was measured by using Universal Testing Machine. Data were analyzed statistically using One-way Analysis of Variance (ANOVA) and post hoc least significant difference (LSD) test.

RESULTS: The result showed that group II had the highest fracture resistance and group III had the lowest fracture resistance. The difference between groups was statistically significant (p value < 0.05).

CONCLUSION: The conclusion showed that adding 4 mm of SFRC as an intermediate layer increased the fracture resistance.

CLINICAL SIGNIFICANCE: The use of SFRC as intermediate layer enhanced the fracture resistance of class II composite restoration.

PMID:33850063

Proc Natl Acad Sci U S A. 2021 Apr 27;118(17):e2100365118. doi: 10.1073/pnas.2100365118.

NO ABSTRACT

PMID:33850050 | DOI:10.1073/pnas.2100365118

Proc Natl Acad Sci U S A. 2021 Apr 20;118(16):e2015188118. doi: 10.1073/pnas.2015188118.

ABSTRACT

Many social and biological systems are characterized by enduring hierarchies, including those organized around prestige in academia, dominance in animal groups, and desirability in online dating. Despite their ubiquity, the general mechanisms that explain the creation and endurance of such hierarchies are not well understood. We introduce a generative model for the dynamics of hierarchies using time-varying networks, in which new links are formed based on the preferences of nodes in the current network and old links are forgotten over time. The model produces a range of hierarchical structures, ranging from egalitarianism to bistable hierarchies, and we derive critical points that separate these regimes in the limit of long system memory. Importantly, our model supports statistical inference, allowing for a principled comparison of generative mechanisms using data. We apply the model to study hierarchical structures in empirical data on hiring patterns among mathematicians, dominance relations among parakeets, and friendships among members of a fraternity, observing several persistent patterns as well as interpretable differences in the generative mechanisms favored by each. Our work contributes to the growing literature on statistically grounded models of time-varying networks.

PMID:33850012 | DOI:10.1073/pnas.2015188118

J Neurol Neurosurg Psychiatry. 2021 Apr 13:jnnp-2020-325141. doi: 10.1136/jnnp-2020-325141. Online ahead of print.

ABSTRACT

OBJECTIVE: To describe decline in muscle strength and physical function in patients with sporadic inclusion body myositis (IBM).

METHODS: Manual muscle testing (MMT), quantitative muscle testing (QMT) and disability scoring using the IBM Functional Rating Scale (IBMFRS) were undertaken for 181 patients for up to 7.3 years. The relationship between MMT, QMT and IBMFRS composite scores and time from onset were examined using linear mixed effects models adjusted for gender and age of disease onset. Adaptive LASSO regression analysis was used to identify muscle groups that best predicted the time elapsed from onset. Cox proportional hazards regression was used to evaluate time to use of a mobility aid.

RESULTS: Multilevel modelling of change in percentage MMT, QMT and IBMFRS score over time yielded an average decline of 3.7% (95% CI 3.1% to 4.3%), 3.8% (95% CI 2.7% to 4.9%) and 6.3% (95% CI 5.5% to 7.2%) per year, respectively. The decline, however, was not linear, with steeper decline in the initial years. Older age of onset was associated with a more rapid IBMFRS decline (p=0.007), but did not influence the rate of MMT/QMT decline. Combination of selected muscle groups allowed for generation of single measures of patient progress (MMT and QMT factors). Median (IQR) time to using a mobility aid was 5.4 (3.6-9.2) years, significantly affected by greater age of onset (HR 1.06, 95% CI 1.04 to 1.09, p<0.001).

CONCLUSION: This prospective observational study represents the largest IBM cohort to date. Measures of patient progress evaluated in this study accurately predict disease progression in a reliable and useful way to be used in trial design.

PMID:33849999 | DOI:10.1136/jnnp-2020-325141

Hosp Pediatr. 2021 Apr 13:hpeds.2020-001636. doi: 10.1542/hpeds.2020-001636. Online ahead of print.

ABSTRACT

BACKGROUND: Penicillin allergy is reported in up to 10% of the general population; however, >90% of patients reporting an allergy are tolerant. Patients labeled as penicillin allergic have longer hospital stays, increased exposure to suboptimal antibiotics, and an increased risk of methicillin-resistant Staphylococcus aureus and Clostridioides difficile. The primary aim with our quality improvement initiative was to increase penicillin allergy delabeling to at least 10% among all hospitalized pediatric patients reporting a penicillin allergy with efforts directed toward patients determined to be low risk for true allergic reaction.

METHODS: Our quality improvement project included several interventions: the development of a multidisciplinary clinical care pathway to identify eligible patients, workflow optimization to support delabeling, an educational intervention, and participation in our institution’s quality improvement incentive program. Our interventions were targeted to facilitate appropriate delabeling by the primary hospital medicine team. Statistical process control charts were used to assess the impact of this intervention pre- and postpathway implementation.

RESULTS: After implementation of the clinical pathway, the percentage of patients admitted to hospital medicine delabeled of their penicillin allergy by discharge increased to 11.7%. More than one-half of those delabeled (51.2%) received a penicillin-based antimicrobial at time of discharge. There have been no adverse events or allergic reactions requiring emergency medication administration since pathway implementation.

CONCLUSIONS: Our quality improvement initiative successfully increased the rate of penicillin allergy delabeling among low-risk hospitalized pediatric patients, allowing for increased use of optimal antibiotics.

PMID:33849960 | DOI:10.1542/hpeds.2020-001636

J Immunother Cancer. 2021 Apr;9(4):e002501. doi: 10.1136/jitc-2021-002501.

ABSTRACT

BACKGROUND: Immune checkpoint inhibitors (ICIs) are the new standard of care in microsatellite instability-high (MSI-H)/deficient mismatch repair (dMMR) metastatic colorectal cancer (mCRC). Since tumor response dynamic parameters already shown a strong association with survival outcomes in patients with mCRC treated with first-line therapy, we investigated the association of early tumor shrinkage (ETS) and depth of response (DoR) in patients with MSI-H/dMMR mCRC treated with ICIs.

METHODS: This is a retrospective, multicenter, cohort study in patients with dMMR and/or MSI-high mCRC treated with ICIs (anti-PD-1/PD-L1 with or without anti-CTLA-4 agents) with measurable disease and at least one post-baseline radiological disease reassessment. The Kaplan-Meier method and Cox proportional-hazards regression models were used for survival analyses. A maximally selected statistics method in a Cox regression model for progression-free survival (PFS) was used to determine the optimal cut-offs for ETS and DoR.

RESULTS: We included a total of 169 patients: 116 (68.6%) were treated with anti-PD-1 monotherapy, whereas 53 (31.4%) with anti-PD-1 plus anti-CTLA-4 agents. Patients with primary progressive disease (N=37, 21.9%), experienced an extremely poor overall survival (OS) and were evaluated separately. In patients with clinical benefit, we observed a significant association between ETS and DoR with both OS and PFS, and we identified a relative reduction of at least 1% as the optimal cut-off for ETS and a relative reduction of at least 50% as the optimal cut-off for DoR.

CONCLUSIONS: ETS and DoR are important prognostic factors in patients with MSI-high mCRC treated with ICIs that might be useful to design treatment intensification/deintensification strategies. A prospective validation of both is warranted.

PMID:33849927 | DOI:10.1136/jitc-2021-002501

Ann Rheum Dis. 2021 Apr 13:annrheumdis-2021-220142. doi: 10.1136/annrheumdis-2021-220142. Online ahead of print.

NO ABSTRACT

PMID:33849919 | DOI:10.1136/annrheumdis-2021-220142

Cancer Prev Res (Phila). 2021 Apr 13:canprevres.0581.2020. doi: 10.1158/1940-6207.CAPR-20-0581. Online ahead of print.

ABSTRACT

Current therapies for breast cancer prevention only prevent estrogen receptor positive (Er+) disease and toxicity limits use of these agents. Vitamin D is a potential prevention therapy for both Er+ and Er- disease and is safe with few side effects. This study evaluates the effect of one-year of vitamin D supplementation on mammographic density (MD), a biomarker of breast cancer risk in a multicenter randomized controlled trial. Premenopausal women with > 25% MD and no history of cancer, were randomly assigned to 2000IU of vitamin D or placebo orally daily for 1-year. Change in percent MD was evaluated using Cumulus software after all participants completed treatment. Three hundred women enrolled between 1/2011 and 12/2013 with a mean age of 43 and diverse ethnicity (14% Hispanic, 12% African American [AA]). Supplementation significantly increased vitamin D levels compared to placebo (14.5 ng/mL vs -1.6 ng/mL; p<0.0001) with all participants on the Vitamin D arm achieving vitamin D sufficiency at 12 months. Vitamin D was safe and well tolerated. After adjustment for baseline MD, the mean between-arm difference (vitamin D vs placebo) at 1 year was -0.75 [-.26, 1.76 p=0.56]. A greater effect was seen for women with >50% MD and AA women, although neither reached significance. This randomized controlled trial demonstrated significant improvement in vitamin D levels with 2000 IU for one year, with 100% of supplemented women achieving sufficiency. However, a null effect was seen regarding change in MD for premenopausal women (the primary outcome of the study).

PMID:33849913 | DOI:10.1158/1940-6207.CAPR-20-0581

BMJ Open. 2021 Apr 13;11(4):e047134. doi: 10.1136/bmjopen-2020-047134.

ABSTRACT

BACKGROUND: Cardiac rehabilitation (CR) decreases the morbidity and mortality risk among patients with cardiac diseases; however, the impact of CR on patients with diabetes remains underexplored. This is a protocol for a systematic review and meta-analysis methodology to explore if the effect of CR on mortality and morbidity is the same in patients with type 2 diabetes compared with patients without diabetes.

METHODS AND ANALYSIS: Interventional and non-interventional studies comparing the effect of CR, for at least 1 month, on all-cause mortality and cardiovascular outcomes including fatal and non-fatal myocardial infarction, revascularisation and rehospitalisation in adults with cardiac diseases will be deemed eligible for inclusion. Studies published between 1990 and 2020 will be searched in PubMed, Embase, Cochrane, CINAHL, Scopus and in registries for randomised controlled trials. Eligible studies will be selected using the Covidence software, and their salient details regarding the design, population, tested interventions and outcomes of interest will be gathered. The quality of studies to be deemed eligible and reviewed will be assessed using the Cochrane Collaboration and National Heart, Lung, and Blood Institute’s tools. The appraisal process will be based on the study design (interventional and non-interventional). In the meta-analysis step, the pooled effect of CR on the outcomes will be estimated. All meta-analyses will be done using the random-effects model approach (inverse-variance method). I ² and p value of χ² statistics will guide the heterogeneity assessment. Subgroup analyses will also be performed. The small study effect will be investigated by generating the funnel plots. The symmetry of the latter will be tested by performing Egger’s test.

ETHICS AND DISSEMINATION: The systematic review will use data from published literature; hence, no ethical approval will be required. Findings of the systematic review and meta-analysis will be published in peer-reviewed international journals and will be disseminated in local and international scientific meetings.

PROSPERO REGISTRATION NUMBER: CRD42020148832.

PMID:33849857 | DOI:10.1136/bmjopen-2020-047134