Alveolar ridge preservation with guided bone regeneration or socket seal technique. A randomised, single-blind controlled clinical trial

OBJECTIVES: To compare radiographic bone changes, following alveolar ridge preservation (ARP) using Guided Bone Regeneration (GBR), a Socket Seal (SS) technique or unassisted socket healing (Control). MATERIAL AND METHODS: Patients requiring a single rooted tooth extraction in the anterior maxilla, were randomly allocated into: GBR, SS and Control groups (n= 14/). Cone Beam Computed Tomography (CBCT) images were recorded post‐extraction and at 4 months, the mid‐buccal and mid‐palatal alveolar ridge heights (BARH/PARH) were measured. The alveolar ridge width, cross‐sectional socket and alveolar‐process area changes, implant placement feasibility, requirement for bone augmentation and post‐surgical complications were also recorded. RESULTS: BARH and PARH was found to increase with the SS (0.65 mm ± 1.1/0.65 mm ± 1.42) techniques, stabilise with GBR (0.07 mm ± 0.83/0.86 mm ±1.37) and decrease in the Control (−0.52 mm ± 0.8/−0.43 mm ± 0.83). Statistically significance was found when comparing the GBR and SS BARH (p = .04/.005) and GBR PARH (p = .02) against the Control. GBR recorded the smallest reduction in alveolar ridge width (−2.17 mm ± 0.84), when compared to the Control (−2.3 mm ± 1.11) (p = .89). A mid‐socket cross‐sectional area reduction of 4% (−2.27 mm(2) ± 11.89), 1% (−0.88 mm(2) ± 15.48) and 13% (−6.93 mm(2) ± 8.22) was found with GBR, SS and Control groups (GBR vs. Control p = .01). The equivalent alveolar process area reduction was 8% (−7.36 mm(2) ± 10.45), 6% (−7 mm(2) ± 18.97) and 11% (−11.32 mm(2) ± 10.92). All groups supported implant placement, with bone dehiscence noted in 57% (n = 4), 64%(n = 7) and 85%(n = 12) of GBR, SS and Control cases (GBR vs. Control p = .03). GBR had a higher risk of swelling and mucosal colour change, with SS associated with graft sequestration and matrix breakdown. CONCLUSION: GBR ARP was found to be more effective at reducing radiographic bone dimensional changes following tooth extraction

Is alveolar ridge preservation an overtreatment?

The morphology and dimensions of the postextraction alveolar ridge are important for the surgical and restorative phases of implant treatment. Adequate new bone formation and preservation of alveolar ridge dimensions following extraction will facilitate installation of the implant in a restorative position, while preservation of soft tissue contour and volume is essential for an aesthetic and implant-supported restoration with healthy peri-implant tissues. Alveolar ridge preservation (ARP) refers to any procedure that aims to: (i) limit dimensional changes in the alveolar ridge after extraction facilitating implant placement without additional extensive bone and soft tissue augmentation procedures (ii) promote new bone formation in the healing alveolus, and (iii) promote soft tissue healing at the entrance of the alveolus and preserve the alveolar ridge contour. Although ARP is a clinically validated and safe approach, in certain clinical scenarios, the additional clinical benefit of ARP over unassisted socket healing has been debated and it appears that for some clinicians may represent an overtreatment. The aim of this critical review was to discuss the evidence pertaining to the four key objectives of ARP and to determine where ARP can lead to favorable outcomes when compared to unassisted socket healing

The efficacy of supplementary sonic irrigation using the EndoActivator® system determined by removal of a collagen film from an ex vivo model

Aim: To evaluate the efficacy of sonic irrigation (EndoActivator®) using various polymer tips and power-settings in a stained collagen ex-vivo model. / Methodology: Fifty human, straight single-rooted extracted teeth were prepared to size 40,.08 taper. The roots were split longitudinally; stained collagen applied to the canal surfaces, photographed and re-assembled. The canals were subjected to syringe without supplementary (Group 1, n = 10), or with supplementary sonic (groups 2–5, n = 10) irrigation. EndoActivator® tip sizes (size 15, .02 taper for groups 2 & 3, size 35,.04 taper for groups 4 & 5) and power-settings (Low for groups 2 & 4, high for groups 3 & 5) were tested. After irrigation, the canals were re-photographed and the area of residual stained-collagen was quantified using the UTHSCA Image Tool program (Version 3.0). The data were analysed using Wilcoxon signed rank test and General Linear Mixed Models. / Results: Supplementary sonic irrigation using EndoActivator® resulted in significantly (P 0.5). / Conclusions: Supplementary sonic irrigation using the EndoActivator® system was significantly more effective in removing stained collagen from the canal surface than syringe irrigation alone. EndoActivator® used with large-tip (size 35, .04 taper) and high power-setting in size 40,.08 taper canals was more effective than other combinations

Learning to trust: trust and attachment in early psychosis

Background Distrust and social dysfunction are characteristic in psychosis and may arise from attachment insecurity, which is elevated in the disorder. The relationship between trust and attachment in the early stages of psychosis is unknown, yet could help to understand interpersonal difficulties and disease progression. This study aimed to investigate whether trust is reduced in patients with early psychosis and whether this is accounted for by attachment avoidance and attachment anxiety. Method We used two trust games with a cooperative and unfair partner in a sample of 39 adolescents with early psychosis and 100 healthy controls. Results Patients had higher levels of attachment anxiety, but the groups did not differ in attachment avoidance. Basic trust was lower in patients than controls, as indicated by lower initial investments. During cooperation patients increased their trust towards levels of controls, i.e. they were able to learn and to override initial suspiciousness. Patients decreased their trust less than controls during unfair interactions. Anxious attachment was associated with higher basic trust and higher trust during unfair interactions and predicted trust independent of group status. Discussion Patients showed decreased basic trust but were able to learn from the trustworthy behaviour of their counterpart. Worries about the acceptance by others and low self-esteem are associated with psychosis and attachment anxiety and may explain behaviour that is focused on conciliation, rather than self-protection

A Comparison of Azacitidine and Decitabine Activities in Acute Myeloid Leukemia Cell Lines

Background: The cytidine nucleoside analogs azacitidine (AZA) and decitabine (DAC) are used for the treatment of patients with myelodysplastic syndromes and acute myeloid leukemia (AML). Few non-clinical studies have directly compared the mechanisms of action of these agents in a head-to-head fashion, and the agents are often viewed as mechanistically similar DNA hypomethylating agents. To better understand the similarities and differences in mechanisms of these drugs, we compared their in vitro effects on several end points in human AML cell lines. Methodology/Principal Findings: Both drugs effected DNA methyltransferase 1 depletion, DNA hypomethylation, and DNA damage induction, with DAC showing equivalent activity at concentrations 2- to 10-fold lower than AZA. At concentrations above 1 mM, AZA had a greater effect than DAC on reducing cell viability. Both drugs increased the sub-G1 fraction and apoptosis markers, with AZA decreasing all cell cycle phases and DAC causing an increase in G2-M. Total protein synthesis was reduced only by AZA, and drug-modulated gene expression profiles were largely non-overlapping. Conclusions/Significance: These data demonstrate shared mechanisms of action of AZA and DAC on DNA-mediated markers of activity, but distinctly different effects in their actions on cell viability, protein synthesis, cell cycle, and gene expression. The differential effects of AZA may be mediated by RNA incorporation, as the distribution of AZA in nucleic aci

Long Type I X-ray Bursts and Neutron Star Interior Physics

Superbursts are very energetic Type I X-ray bursts discovered in recent years by long term monitoring of X-ray bursters, believed to be due to unstable ignition of carbon in the deep ocean of the neutron star. A number of "intermediate duration" bursts have also been observed, probably associated with ignition of a thick helium layer. We investigate the sensitivity of these long X-ray bursts to the thermal profile of the neutron star crust and core. We first compare cooling models of superburst lightcurves with observations, and derive constraints on the ignition mass and energy release, and then calculate ignition models for superbursts and pure helium bursts, and compare to observations. The superburst lightcurves and ignition models imply that the carbon mass fraction is approximately 20% or greater in the fuel layer, constraining models of carbon production. However, the most important result is that when Cooper pairing neutrino emission is included in the crust, the temperature is too low to support unstable carbon ignition at the observed column depths. Some additional heating mechanism is required in the accumulating fuel layer to explain the observed properties of superbursts. If Cooper pair emission is less efficient than currently thought, the observed ignition depths for superbursts imply that the crust is a poor conductor, and the core neutrino emission is not more efficient than modified URCA. The observed properties of helium bursts support these conclusions, requiring inefficient crust conductivity and core neutrino emission.Comment: submitted to ApJ (22 pages, 26 figures

How not to attack intelligent design creationism: philosophical misconceptions about methodological naturalism

In recent controversies about Intelligent Design Creationism (IDC), the principle of methodological naturalism (MN) has played an important role. In this paper, an often neglected distinction is made between two different conceptions of MN, each with its respective rationale and with a different view on the proper role of MN in science. According to one popular conception, MN is a self-imposed or intrinsic limitation of science, which means that science is simply not equipped to deal with claims of the supernatural (Intrinsic MN or IMN). Alternatively, we will defend MN as a provisory and empirically grounded attitude of scientists, which is justified in virtue of the consistent success of naturalistic explanations and the lack of success of supernatural explanations in the history of science (Provisory MN or PMN). Science does have a bearing on supernatural hypotheses, and its verdict is uniformly negative. We will discuss five arguments that have been proposed in support of IMN: the argument from the definition of science, the argument from lawful regularity, the science stopper argument, the argument from procedural necessity, and the testability argument. We conclude that IMN, because of its philosophical flaws, proves to be an ill-advised strategy to counter the claims of IDC. Evolutionary scientists are on firmer ground if they discard supernatural explanations on purely evidential grounds, instead of ruling them out by philosophical fiat

Theorizing compassion and empathy in educational contexts: what are compassion and empathy and why are they important?

The world is in constant change with growing inequality and access. When you watch the news, you are confronted with national disasters, wars/conflicts, waves of refugees and other crimes against humanity. At a national level, many countries have a changing political landscape that has seen a rise in fundamentalist nationalist parties leading to a discourse of 'problematic immigrants'. We also witness the decline of democratic ideals and the ethos of supporting people in society as politicians are influenced by capitalist ideals and individual gain. In essence, the world appears to be becoming meaner, with little understanding shown to others. When did values change