Comparison of natural and artificial root caries lesions using microcomputed tomography and microhardness test.

BACKGROUND: This study compared natural root caries lesions with artificial root caries lesions prepared with one of the two demineralising solutions. METHODS: Twelve natural root caries lesions on upper incisors and 24 artificial root lesions were prepared on sound root surfaces using 50 mM acetic acid, 1.5 mM CaCl2 , 0.9 mM KH2 PO4 at pH 5.0 or 80 mL/L Noverite K-702 polyacrylate solution, 500 mg/L hydroxyapatite, 0.1 mol/L lactic acid at pH 4.8 (n = 12/group) for 96 hours. Lesions were scanned using micro-CT. Inciso-gingival oriented images were analysed and mineral density calculated at 7.5 µm increments from the surface to 225-µm deep. Sectioned lesions were analysed by Knoop microhardness up to 250 µm from the lesion surface. Data were analysed by the Dunn's test with Bonferroni correction. RESULTS: Natural and artificial lesion mean mineral densities were not statistically different (P > 0.05). Mineral density from the surface to 75 µm was greater in natural lesions and from 150 to 225 µm was greater in artificial lesions (P < 0.05). Microhardness values were statistically higher in artificial lesions (P < 0.05); no difference was found among artificial lesions produced by the two solutions (P > 0.05). Mineral density and microhardness of natural and artificial root caries are different from each other. A greater mineralized surface layer existed on natural lesions.

Dentinal microcracks and cemental tears related to chemo-mechanical root canal instrumentation: a micro-CT Cadaver Study.

BACKGROUND: The prevalence of radicular defects after root canal instrumentation is unresolved. This study used micro-CT to assess the relationship between the formation of radicular defects and chemo-mechanical instrumentation in a cadaver model. METHODS: Maxillary and mandibular molars (n = 24) were sectioned from cadaver specimens as a tissue block containing the teeth, alveolar bone and attached mucogingival tissues. After a baseline micro-CT scan (13.45 µm), the specimens were distributed into 3 groups (n = 8 molars): Reciproc® , ProTaper Next™ and Mtwo® . Micro-CT scans of each specimen were obtained after access, glide path and preparation with each instrument. The pre-operative and final post-operative micro-CT cross-sectional images of the roots were screened by two blinded examiners to identify any pre-existing and new radicular defects. Pre-existing and new radicular defects were examined histologically. RESULTS: Overall, 16 pre-existing radicular defects were identified in 12 of the 24 molars (50%). Most of these were cemental tears (87.5%), and not true dentinal microcracks. New dentinal microcracks were observed in the post-operative micro-CT scans of only 3 canals (3.9%; 3/77). However, only one of these defects was found to be present histologically. CONCLUSIONS: Within the limitations of the study, chemo-mechanical instrumentation did not routinely promote the formation of radicular defects.

Root canal instrumentation efficacy of non-fused and fused primary molar roots: a micro-computed tomography study.

PURPOSE: Pulpectomy may be indicated in restorable primary teeth exhibiting irreversible pulpitis or pulpal necrosis. The purpose of this study was to compare the cleaning and shaping efficacy of NiTi systems (Reciproc® Blue and MTwo®) with manual stainless-steel instrumentation in primary molars using micro-CT analysis. METHODS: Fifty-seven maxillary second primary molars were scanned using micro-CT. Teeth with three divergent roots were divided randomly (n = 15) according to instrument type (K file, MTwo®, and Reciproc® Blue). Teeth with root fusion were instrumented manually as a separate group (n = 12). Pre- and post-instrumentation micro-CT images were superimposed, and the instrumentation area (IA) and procedural complications were recorded. RESULTS: No statistically significant differences in IA between file systems was observed in the non-fused teeth. The mean IA of fused roots was significantly lower than in the non-fused distobuccal (p = 0.003) and palatal (p < 0.001) roots. The root segment had a significant effect on IA (p < 0.001) and the highest mean IA was observed in the apical third. Manual instrumentation had fewer procedural complications compared with rotary systems. CONCLUSION: No differences were determined in the cleaning and shaping effectiveness of all systems in non-fused teeth. Uninstrumented areas (> 60%) occurred in both non-fused and fused primary teeth with fewer procedural complications observed after manual instrumentation.

Root canal morphology of primary maxillary second molars: a micro-computed tomography analysis.

AIM: Successful endodontic treatment of primary teeth requires comprehensive knowledge and understanding of root canal morphology. The purpose of this study was to investigate the root canal configurations of primary maxillary second molars using micro-computed tomography. METHODS: Extracted human primary maxillary second molars (n = 57) were scanned using micro-computed tomography and reconstructed to produce three-dimensional models. Each root canal system was analysed qualitatively according to Vertucci's classification. RESULTS: 22.8% (n = 13) of the sample presented with the fusion of the disto-buccal and palatal roots; of these, Type V was the most prevalent classification. For teeth with three separate roots (n = 44), the most common root canal type was Type 1 for the palatal canal (100%) and disto-buccal canal (77.3%) and Type V for the mesio-buccal canal (36.4%). Overall, 7% (n = 4) of mesio-buccal canals were 'unclassifiable'. CONCLUSION: The root canal systems of primary maxillary second molars were not only complex but had a range of configurations that may contribute to unfavourable clinical outcomes after endodontic treatment.

MEPROCS framework for Craniofacial Superimposition: Validation study.

Craniofacial Superimposition (CFS) involves the process of overlaying a skull with a number of ante-mortem images of an individual and the analysis of their morphological correspondence. The lack of unified working protocols and the absence of commonly accepted standards, led to contradictory consensus regarding its reliability. One of the more important aims of 'New Methodologies and Protocols of Forensic Identification by Craniofacial Superimposition (MEPROCS)' project was to propose a common framework for CFS, what can be considered the first international standard in the field. The framework aimed to serve as a roadmap for avoiding particular assumptions that could bias the process. At the same time, it provides some empirical support to certain practices, technological means, and morphological criteria expected to facilitate the application of the CFS task and to improve its reliability. In order to confirm the utility and potential benefits of the framework use, there is a need to empirically evaluate it in CFS identification scenarios as close as possible to the reality. Thus, the purpose of this study is to validate the CFS framework developed. For that aim 12 participants were asked to report about a variable number of CFS following all the recommendations of the framework. The results are analysed and discussed according to the framework understanding and fulfilment, the participants' performance, and the correlation between expected decisions and those given by the participants. In view of the quantitative results and qualitative examination criteria we can conclude that those who follow the MEPROCS recommendations improve their performance.

Study on the performance of different craniofacial superimposition approaches (I).

As part of the scientific tasks coordinated throughout The 'New Methodologies and Protocols of Forensic Identification by Craniofacial Superimposition (MEPROCS)' project, the current study aims to analyse the performance of a diverse set of CFS methodologies and the corresponding technical approaches when dealing with a common dataset of real-world cases. Thus, a multiple-lab study on craniofacial superimposition has been carried out for the first time. In particular, 26 participants from 17 different institutions in 13 countries were asked to deal with 14 identification scenarios, some of them involving the comparison of multiple candidates and unknown skulls. In total, 60 craniofacial superimposition problems divided in two set of females and males. Each participant follow her/his own methodology and employed her/his particular technological means. For each single case they were asked to report the final identification decision (either positive or negative) along with the rationale supporting the decision and at least one image illustrating the overlay/superimposition outcome. This study is expected to provide important insights to better understand the most convenient characteristics of every method included in this study.

Teachers' experiences of their role following the implementation of Project 2000: a qualitative approach.

This study focuses upon the experiences of a group of six nurse teachers who experienced change in their role following the implementation of Project 2000 at their place of work. The teachers were interviewed using the informal interview method which allowed the researcher to obtain detailed information and get to know them as people. Qualitative analysis based on a modified grounded theory approach revealed four recurrent themes which were discussed in terms of the context of the study and existing theories. The study highlights the feasibility of the grounded theory approach and the informal interviews as a means of collecting detailed data and eliciting in-depth understanding of the participants' experience of their changed role from their perspective. The informal interviews and the researcher's knowledge of the participants and the context in which the study was conducted have proved to be helpful in generating categories which describe the teachers' experiences of the changes in their role.

Endocarditis caused by Brucella melitensis.

OBJECTIVE: To describe the management of an uncommon but serious infection in Australia. CLINICAL FEATURES: A 25-year-old woman developed endocarditis after residence in Turkey and consumption of goat dairy products. Brucella melitensis was isolated from blood cultures. INTERVENTION AND OUTCOME: The valve remained infected after prolonged intravenous administration of trimethoprim-sulfamethoxazole, gentamicin and rifampicin. Uncontrolled sepsis and worsening haemodynamic function necessitated valve replacement. To date the patient remains well while taking trimethoprim-sulfamethoxazole and rifampicin. CONCLUSION: Endocarditis due to Brucella spp. is uncommon in Australia. This infection is difficult to cure with antimicrobial therapy alone and early surgical intervention is advisable.

Chronic liver disease in asymptomatic hepatitis C antibody positive blood donors.

The risks of acquisition of hepatitis C infection, the histological spectrum of liver disease, and the presence of viraemia were investigated in anti-hepatitis C virus (HCV) antibody positive blood donors. All 357 (0.64%) blood donors to the South Australian Red Cross Transfusion Service found to have anti-HCV antibody during the first seven months of testing in 1990 were assessed, and 70 (19.6%) were found to have elevated alanine transaminase levels. These subjects were referred for participation in the study; 31 presented for enrollment. Sixteen (52%) of the 31 patients had previously used intravenous drugs, four (13%) had been transfused, two (6%) had a history of occupational exposure to blood, and three (10%) had tattoos and ear-piercing as possible risk factors for acquisition of hepatitis C. There was no history of parenteral exposure in six (16%). None of these donors had clinical evidence of liver disease, but in all 24 of the 31 who had a liver biopsy there was histological evidence of significant liver damage. Twelve had evidence of chronic active hepatitis. All 24 subjects biopsied were viraemic as judged by the presence of HCV RNA in serum.

Isospora belli infection. A report of two cases in patients with AIDS.

OBJECTIVE: To present the findings of Isospora belli infection in two patients with the acquired immunodeficiency syndrome (AIDS). CLINICAL FEATURES: One patient was part Aboriginal, the other an immigrant recently arrived from Peru. Both men were infected with the human immunodeficiency virus (HIV). They presented with watery diarrhoea, one with severe weight loss. Isospora belli oocysts were detected in multiple faecal specimens from both patients. One patient had a concomitant infection with Cryptosporidium sp. INTERVENTION AND OUTCOME: There was a rapid response to treatment with cotrimoxazole (960 mg, four times a day for 10 days). A complete response was obtained in the patient with concurrent cryptosporidiosis. The diarrhoea recurred after cessation of treatment, necessitating maintenance therapy. CONCLUSION: Although Isospora belli is an uncommon cause of gastroenteritis in Australia, it is increasingly recognised as a cause of diarrhoea in travellers, immigrants from endemic areas and immunocompromised people. It has also been reported in the Aboriginal community; this article reports the first case of AIDS-related isosporiasis in an Aborigine. It is likely that both patients acquired Isospora belli before they become HIV seropositive.