Aim
To investigate the prevalence, location and pattern of pre‐existing microcracks in non‐endodontically treated teeth from fresh cadavers. Micro‐computed tomography (micro‐CT) technology was used ...as the analytical tool enabling full screening of the root dentine with the teeth retained in their original alveolar socket.
Methodology
As a pilot study and to validate the present method, a series of 4 high‐resolution scans were performed on one bone‐block specimen with teeth collected post‐mortem: (i) entire bone‐block including the teeth, (ii) second molar tooth extracted atraumatically from the bone‐block, (iii) extracted tooth dehydrated to induce dentinal defects and (iv) entire bone‐block following reinsertion of the extracted tooth into its matching alveolar socket. In the main study, forty‐two dentoalveolar maxillary and mandibular bone‐blocks each containing 3–5 adjacent teeth (a total of 178 teeth) were collected post‐mortem and scanned in a micro‐CT device. All cross‐section images of the 178 teeth (n = 65 530) were screened from the cementoenamel junction to the apex to identify the presence of dentinal defects.
Results
In the pilot study, the microcracks observable when the dehydrated tooth was outside the bone‐block remained detectable when the entire bone‐block plus reinserted tooth was scanned. This means that the screening process revealed the presence of the same microcracks in both experimental situations (the tooth outside and inside the maxillary bone‐block). From a total of 178 teeth in the bone‐blocks removed from cadavers, 65 530 cross‐sectional images were analysed and no dentinal microcracks were detected.
Conclusions
This in situ cadaveric model revealed the lack of pre‐existing dentinal microcracks in non‐endodontically treated teeth. Thus, the finding of dentinal microcracks observed in previous cross‐sectional images of stored extracted teeth is unsound and not valid. It should be assumed that microcracks observed in stored extracted teeth subjected to root canal procedures are a result of the extraction process and/or the post‐extraction storage conditions. Therefore, as a consequence, the presence of such dentinal microcracks in stored extracted teeth – observable in cross‐sectional images of the roots – should be referred to as experimental dentinal microcracks.
Methods of anatomical education have, as with many facets of normal life, been forced to evolve rapidly due to the Covid-19 pandemic. Whilst some authors claim that cadaver dissection is now under ...threat, we believe the centuries-old practice can and must be upheld.
We previously reported
the presence of amyloid-β protein (Aβ) deposits in individuals with Creutzfeldt-Jakob disease (CJD) who had been treated during childhood with human cadaveric pituitary-derived ...growth hormone (c-hGH) contaminated with prions. The marked deposition of parenchymal and vascular Aβ in these relatively young individuals with treatment-induced (iatrogenic) CJD (iCJD), in contrast to other prion-disease patients and population controls, allied with the ability of Alzheimer's disease brain homogenates to seed Aβ deposition in laboratory animals, led us to argue that the implicated c-hGH batches might have been contaminated with Aβ seeds as well as with prions. However, this was necessarily an association, and not an experimental, study in humans and causality could not be concluded. Given the public health importance of our hypothesis, we proceeded to identify and biochemically analyse archived vials of c-hGH. Here we show that certain c-hGH batches to which patients with iCJD and Aβ pathology were exposed have substantial levels of Aβ
, Aβ
and tau proteins, and that this material can seed the formation of Aβ plaques and cerebral Aβ-amyloid angiopathy in intracerebrally inoculated mice expressing a mutant, humanized amyloid precursor protein. These results confirm the presence of Aβ seeds in archived c-hGH vials and are consistent with the hypothesized iatrogenic human transmission of Aβ pathology. This experimental confirmation has implications for both the prevention and the treatment of Alzheimer's disease, and should prompt a review of the risk of iatrogenic transmission of Aβ seeds by medical and surgical procedures long recognized to pose a risk of accidental prion transmission
.
Human cadaveric dissection has been utilized as the major teaching method for human anatomy since ancient Greece in the 3rd century Before Christ (BC). Globally, despite the advancement of modern ...technology and changing teaching methods, human cadaveric dissection has remained the major platform for teaching gross anatomy to medical and health science students. Cadaveric dissection provides for a comprehensive understanding of the three-dimensional relationships that are so important in comprehending human anatomy for clinical practice. Though many scattered studies have been published so far, worldwide research that represents a global level of knowledge and attitude towards ethical cadaver dissection is lacking, and their results have been contradictory and inconclusive. Therefore, this systematic review and meta-analysis aimed to estimate the pooled prevalence of knowledge and attitude towards ethical cadaver dissection among medical and health sciences students.
This review was reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P) guidelines. International databases like PubMed, SCOPUS, Google Scholar, and Science Direct were systematically searched on knowledge and attitude towards ethical cadaver dissection among medical and health sciences students from 1997 to 2020. To analyze the data, STATA™ Version 14.1 was used. To determine heterogeneity and publication bias, the Cochrane Q and I2 test, and both Egger's and Begger's tests were used, respectively. The pooled prevalence and odds ratios were estimated with confidence intervals of 95%. Finally, a random-effects meta-analysis model was calculated to estimate the pooled prevalence of knowledge and attitude towards ethical cadaver dissection.
We screened a total of 460 articles. Of these, 15 studies were included in the final systematic review and meta-analysis. The pooled prevalence of knowledge and attitude towards ethical cadaver dissection among medical and health sciences students were 66.78% (95% CI: 45.62, 87.94; I2 = 98.6%, p-value <0.001) and 67.49% (95% CI: 56.07, 78.91; I2 = 98.7%, p-value <0.001) respectively. The subgroup analysis was conducted on 3 Ethiopian studies (59.87% 95% CI: 15.33, 104.41), 5 researches in India (73.24% 95% CI: 56.07, 90.42), 5 on the African continent (64.4% 95% CI: 37.85, 90.95) and 9 in Asia (68.34% 95% 31 CI: 55.35, 81.33).
Overall, two-thirds of the participants had adequate knowledge and a favorable attitude towards ethical cadaver dissection, whereas one-third had inadequate knowledge and an unfavorable attitude. The dissection room should be environmentally friendly and conducive to overcome the obstacles that students face when practicing cadaveric dissection. Furthermore, instructors must psychologically and emotionally prepare students before they enter the dissecting room so that they may become more active participants in cadaver dissection, improving anatomical knowledge and future surgical skill. Moreover, medical curriculum developers and policymakers should understand the implications of dissection in clinical practice. Further research is also needed to see if factors impacting knowledge and attitudes towards ethical cadaver dissection are consistently distributed worldwide, nationally, and regionally, so that appropriate interventional strategy may be implemented.
•The pooled prevalence of knowledge and attitude towards ethical cadaver dissection were 66.78% and 67.49% respectively.•Favorable attitude towards ethical cadaver dissection in Ethiopia and India were 59.87% and 73.24% respectively.•Favorable attitude towards ethical cadaver dissection in Africa and Asia were 64.4% and 68.34% respectively.
A new approach is taken to estimating the time of death based on cadaver temperatures. The predictions are obtained by using numerical simulation that can be performed in a case‐by‐case scenario. ...Such a method enables time‐of‐death predictions for persons of any size and weight and in any thermal environment. An added advantage of the method is that it is not dependent upon an identification of the individual tissue layers and regions. Rather, a homogeneous tissue model is used, and the results that are obtained agree closely with the results of prior estimation methods and also with a prior published case study. Among the results presented in this study are various convective environments in both air and water (or a combination for a partially submerged body). The orientation of the body (face down vs face up) is investigated. It is found that when a body is face up, its body core temperature is more responsive to the ambient conditions, compared with a face‐down orientation, at least for some partial‐submergence depths. The method disclosed here can also be used to handle situations, where the environmental conditions are changing (such as diurnal temperature variations, variation in cloudy or sunny skies, etc.). Current nomogram methods are not able to handle such timewise variations.
Purpose
10% Formalin (F10)-fixed cadavers have disadvantages such as disturbing smell, mucosal irritation, discoloration and rigidity. We aimed to determine a suitable, simple and cost-effective ...embalming method that preserves color, texture, pliability and flexibility of the tissues for a long time without a disturbing smell and mucosal irritation. The embalmed cadavers were expected to be durable against environmental effects, utilizable for multiple and repetitive surgical trainings and instrumentations.
Methods
Eight male (six intact, two autopsied bodies) and four female (three intact and one imported trunk) human cadavers were preserved with modified Larssen solution (MLS). Preserved bodies were kept in the deep freezers at −18/−20 °C. Bodies were allowed to thaw at room temperature 3 days prior to use. They were used in postgraduate hands-on courses for several medical disciplines. Each course lasted at least 1 day and during this period the bodies were stayed at room temperature. Assessments of 30 trainers and 252 trainees were collected during the courses. Additionally, the organoleptic characteristics of the fresh frozen (FF), preserved with MLS and F10-fixed cadavers were compared.
Results
The colors of muscles, fasciae, fatty tissue, nerves and vessels were evaluated and life-like tissues of MLS cadavers were impressive. There were no obvious or disturbing smell and sign of putrefaction of the MLS cadavers.
Conclusions
MLS is a sustainable and relatively affordable soft cadaver embalming method. Its application is same as in other conventional methods and does not need new equipment. This article indicates the success of the MLS method in human cadavers.
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