Consensus Guideline on the Management of Epilepsy in Egypt: A National Delphi Consensus Study.

OBJECTIVE: In epilepsy, early diagnosis, accurate determination of epilepsy type, proper selection of antiseizure medication, and monitoring are all essential. However, despite recent therapeutic advances and conceptual reconsiderations in the classification and management of epilepsy, serious gaps are still encountered in day-to-day practice in Egypt as well as several other resource-limited countries. Premature mortality, poor quality of life, socio-economic burden, cognitive problems, poor treatment outcomes, and comorbidities are major challenges that require urgent actions to be implemented at all levels. In recognition of this, a group of Egyptian epilepsy experts met through a series of consecutive meetings to specify the main concepts concerning the diagnosis and management of epilepsy, with the ultimate goal of establishing a nationwide Egyptian consensus. METHODS: The consensus was developed through a modified Delphi methodology. A thorough review of the most recent relevant literature and international guidelines was performed to evaluate their applicability to the Egyptian situation. Afterward, several remote and live rounds were scheduled to reach a final agreement for all listed statements. RESULTS: Of 278 statements reviewed in the first round, 256 achieved ≥80% agreement. Live discussion and refinement of the 22 statements that did not reach consensus during the first round took place, followed by final live voting then consensus was achieved for all remaining statements. SIGNIFICANCE: With the implementation of these unified recommendations, we believe this will bring about substantial improvements in both the quality of care and treatment outcomes for persons with epilepsy in Egypt. PLAIN LANGUAGE SUMMARY: This work represents the efforts of a group of medical experts to reach an agreement on the best medical practice related to people with epilepsy based on previously published recommendations while taking into consideration applicable options in resource-limited countries. The publication of this document is expected to minimize many malpractice issues and pave the way for better healthcare services on both individual and governmental levels.

Securing Internet-of-Medical-Things networks using cancellable ECG recognition.

Reinforcement of the Internet of Medical Things (IoMT) network security has become extremely significant as these networks enable both patients and healthcare providers to communicate with each other by exchanging medical signals, data, and vital reports in a safe way. To ensure the safe transmission of sensitive information, robust and secure access mechanisms are paramount. Vulnerabilities in these networks, particularly at the access points, could expose patients to significant risks. Among the possible security measures, biometric authentication is becoming a more feasible choice, with a focus on leveraging regularly-monitored biomedical signals like Electrocardiogram (ECG) signals due to their unique characteristics. A notable challenge within all biometric authentication systems is the risk of losing original biometric traits, if hackers successfully compromise the biometric template storage space. Current research endorses replacement of the original biometrics used in access control with cancellable templates. These are produced using encryption or non-invertible transformation, which improves security by enabling the biometric templates to be changed in case an unwanted access is detected. This study presents a comprehensive framework for ECG-based recognition with cancellable templates. This framework may be used for accessing IoMT networks. An innovative methodology is introduced through non-invertible modification of ECG signals using blind signal separation and lightweight encryption. The basic idea here depends on the assumption that if the ECG signal and an auxiliary audio signal for the same person are subjected to a separation algorithm, the algorithm will yield two uncorrelated components through the minimization of a correlation cost function. Hence, the obtained outputs from the separation algorithm will be distorted versions of the ECG as well as the audio signals. The distorted versions of the ECG signals can be treated with a lightweight encryption stage and used as cancellable templates. Security enhancement is achieved through the utilization of the lightweight encryption stage based on a user-specific pattern and XOR operation, thereby reducing the processing burden associated with conventional encryption methods. The proposed framework efficacy is demonstrated through its application on the ECG-ID and MIT-BIH datasets, yielding promising results. The experimental evaluation reveals an Equal Error Rate (EER) of 0.134 on the ECG-ID dataset and 0.4 on the MIT-BIH dataset, alongside an exceptionally large Area under the Receiver Operating Characteristic curve (AROC) of 99.96% for both datasets. These results underscore the framework potential in securing IoMT networks through cancellable biometrics, offering a hybrid security model that combines the strengths of non-invertible transformations and lightweight encryption.

Association of ACE1 I/D polymorphism and susceptibility to COVID-19 in Egyptian children and adolescents.

BACKGROUND: Given the sparse data on the renin-angiotensin system (RAS) and its biological effector molecules ACE1 and ACE2 in pediatric COVID-19 cases, we investigated whether the ACE1 insertion/deletion (I/D) polymorphism could be a genetic marker for susceptibility to COVID-19 in Egyptian children and adolescents. METHODS: This was a case-control study included four hundred sixty patients diagnosed with COVID-19, and 460 well-matched healthy control children and adolescents. The I/D polymorphism (rs1799752) in the ACE1 gene was genotyped by polymerase chain reaction (PCR), meanwhile the ACE serum concentrations were assessed by ELISA. RESULTS: The ACE1 D/D genotype and Deletion allele were significantly more represented in patients with COVID-19 compared to the control group (55% vs. 28%; OR = 2.4; [95% CI: 1.46-3.95]; for the DD genotype; P = 0.002) and (68% vs. 52.5%; OR: 1.93; [95% CI: 1.49-2.5] for the D allele; P = 0.032). The presence of ACE1 D/D genotype was an independent risk factor for severe COVID-19 among studied patients (adjusted OR: 2.6; [95% CI: 1.6-9.7]; P < 0.001. CONCLUSIONS: The ACE1 insertion/deletion polymorphism may confer susceptibility to SARS-CoV-2 infection in Egyptian children and adolescents. IMPACT: Recent studies suggested a crucial role of renin-angiotensin system and its biological effector molecules ACE1 and ACE2 in the pathogenesis and progression of COVID-19. To our knowledge, ours is the first study to investigate the association of ACE1 I/D polymorphism and susceptibility to COVID-19 in Caucasian children and adolescents. The presence of the ACE1 D/D genotype or ACE1 Deletion allele may confer susceptibility to SARS-CoV-2 infection and being associated with higher ACE serum levels; may constitute independent risk factors for severe COVID-19. The ACE1 I/D genotyping help design further clinical trials reconsidering RAS-pathway antagonists to achieve more efficient targeted therapies.

Relationship between Subclinical Hypothyroidism and Uremic Pruritis in Hemodialysis Patients.

BACKGROUND AND AIM: Uremic pruritus (UP) is one of the most distressing symptoms in hemodialysis (HD) patients. Subclinical hypothyroidism (SCH) is a biochemical condition with high prevalence in HD patients. The present multicentric study aimed to assess the relationship between UP and SCH in HD patients. METHODS: The present cross-sectional study included 328 HD patients. All patients were submitted to careful history through clinical examination and standard laboratory assessment. Pruritis was evaluated using the pruritis visual analog scale (VAS). Patients were diagnosed with SCH if they had TSH levels above the upper limit of the normal reference range in association with normal free thyroxine (FT4) levels. RESULTS: Among the studied patients, there were 196 patients (59.8 %) with UP. Comparison between patients with UP and patients without revealed that patients in the former group had significantly longer HD duration (median (IQR): 47.5 (27.0-72.5) versus 36.0 (23.0-50.5) months, p < 0.001) and lower Kt/v (median (IQR): 1.4 (1.09-1.7) versus 1.54 (1.12-1.91), p = 0.009). Moreover, they had significantly higher ferritin (median (IQR): 653.0 (526.0-800.0) versus 628.0 (470.8- 716.0) ng/mL), hsCRP (median (IQR): 12.0 (8.0-14.0) versus 8.0 (6.0-9.0) mg/dL, p < 0.001) and TSH levels (median (IQR): 4.34 (1.98-5.2) versus 3.34 (1.9-4.85) µIU/ml) with a significantly higher frequency of SCH (45.9 % versus 28.8 %, p = 0.002). Logistic regression analysis identified hemodialysis duration (OR (95%) CI): 1.02 (1.009-1.028), p < 0.001), ferritin levels (OR (95% CI): 1.002 (1.001-1.003), p < 0.001), and SCH (OR (95% CI): 0.54 (0.32-0.89), p = 0.016) as significant predictors of UP. CONCLUSION: The present study suggested a possible link between SCH and the development of UP in HD patients.

A Multicenter Experience of Inducible Clindamycin Resistance in Staphylococcus aureus Infection among 800 Egyptian Patients with or without Diabetes Mellitus.

Staphylococcus aureus causes a wide range of illnesses, from skin infections and persistent bone infections to life-threatening septicemia and endocarditis. Methicillin-resistant S. aureus (MRSA) is one of the most common bacteria that cause nosocomial and community-acquired infections. Clindamycin is one of the most effective treatments for several bacterial infections. Despite this, these infections may develop inducible clindamycin resistance during treatment, leading to treatment failure. This study determined the incidence of inducible clindamycin resistance among S. aureus clinical isolates. A total of 800 S. aureus strains were identified from clinical samples collected from several university hospitals in Egypt. All isolates were examined for the presence of MRSA using cefoxitin (30 µg) and the Kirby Bauer disk diffusion technique. The induction phenotypes of all 800 S. aureus strains were evaluated using the disk approximation test (D test), as recommended by the Clinical and Laboratory Standard Institute. Of the 800 strains of S. aureus, 540 (67.5%) were identified as MRSA and 260 (32.5%) were classified as methicillin-sensitive S. aureus (MSSA). In MRSA infections, clindamycin constitutive and inducible resistance was more frequent than in MSSA infections (27.8% versus 11.5% and 38.9% versus 15.4%, respectively). Clindamycin-sensitive strains were more prevalent in MSSA (53.8%) than in MRSA (20.4%) infections. In conclusion, the frequency of constitutive and inducible clindamycin resistance in MRSA isolates emphasizes the need to use the D test in routine antimicrobial susceptibility testing to evaluate clindamycin susceptibility, as the inducible resistance phenotype can inhibit the action of clindamycin and thus affect treatment efficacy.

Response of varied rice genotypes on cell membrane stability, defense system, physio-morphological traits and yield under transplanting and aerobic cultivation.

Aerobic rice cultivation progresses water productivity, and it can save almost 50% of irrigation water compared to lowland rice with the appropriate development of genotypes and management practices. Two field trials were conducted during 2020, and 2021 seasons to determine the validation of different rice varieties under aerobic cultivation based on their plant defense system, physio-morphological traits, stress indices, grain yield, and water productivity. The experiments were designed in a split-plot design with four replications. Two planting methods, transplanting and aerobic cultivation, were denoted as the main plots, and ten rice genotypes were distributed in the subplots. The results revealed that the planting method varied significantly in all measured parameters. The transplanting method with well watering had the highest value of all measured parameters except leaf rolling, membrane stability index, antioxidant, proline, and the number of unfilled grains. EHR1, Giza179 and GZ9399 as well as A22 genotypes a chief more antioxidant defense system that operated under aerobic conditions. Giza179, EHR1, GZ9399, and Giza178 showed high cell membrane stability and subsequently high validation under such conditions, and also showed efficiency in decreasing water consumption and improving water use efficiency. In conclusion, this study proves that Giza179, EHR1, GZ9399, Giza178, and A22 are valid genotypes for aerobic conditions.

Relation between Soluble CD14 Levels, Inflammation, Subclinical Atherosclerosis and Mortality in Hemodialysis Patients.

BACKGROUND AND AIM: Chronic kidney disease (CKD) is characterized by persistent lowgrade inflammation. Soluble CD14 (sCD14) is involved in many pathological conditions, including inflammation and atherosclerosis. The present study aimed to assess the relationship between sCD14 levels, subclinical atherosclerosis (SCA), inflammation and mortality in Egyptian hemodialysis (HD) patients. PATIENTS AND METHODS: The present longitudinal study included 62 HD patients. All patients were submitted to careful history taking, thorough clinical examination and laboratory assessment for high-sensitivity C-reactive protein (hsCRP) and sCD14. Carotid intima-media thickness (CIMT) was also assessed. Patients were followed for a maximum of 18 months. The primary outcome is patients' mortality. Data were statistically analyzed using standard descriptive, comparative, correlative and regression methods. RESULTS: The present study was conducted on 62 HD patients. They comprised 34 males and 28 females with an age of 54.6 ± 9.0 years. At the end of follow-up, 12 patients (19.4 %) died. It was shown that survivors had significantly lower hsCRP levels (104.2 ± 38.2 versus 134.1 ± 15.3 mg/dL, p < 0.001), lower sCD14 levels (32.7 ± 10.3 versus 47.4 ± 18.4 µg/mL, p = 0.02) and lower CIMT (1.32 ± 0.5 versus 1.5 ± 0.2 mm, p = 0.049). sCD14 levels were significantly correlated with hsCRP (r = 0.4, p = 0.001) and CIMT (r = 0.31, p = 0.013). Multivariate analysis identified HD duration [HR (95% CI): 1.02 (1.0-1.04), p = 0.021] and sCD14 levels [HR (95% CI): 1.06 (1.0-1.12), p = 0.026] as significant predictors of patients' survival. CONCLUSIONS: sCD14 levels in this cohort of HD patients are well-correlated with hsCRP levels and CIMT. In addition, they are significant predictors of patients' mortality.

Vitamin D deficiency and vitamin D receptor FokI polymorphism as risk factors for COVID-19.

BACKGROUND: Given the sparse data on vitamin D status in pediatric COVID-19, we investigated whether vitamin D deficiency could be a risk factor for susceptibility to COVID-19 in Egyptian children and adolescents. We also investigated whether vitamin D receptor (VDR) FokI polymorphism could be a genetic marker for COVID-19 susceptibility. METHODS: One hundred and eighty patients diagnosed to have COVID-19 and 200 matched control children and adolescents were recruited. Patients were laboratory confirmed as SARS-CoV-2 positive by real-time RT-PCR. All participants were genotyped for VDR Fok1 polymorphism by RT-PCR. Vitamin D status was defined as sufficient for serum 25(OH) D at least 30 ng/mL, insufficient at 21-29 ng/mL, deficient at <20 ng/mL. RESULTS: Ninety-four patients (52%) had low vitamin D levels with 74 (41%) being deficient and 20 (11%) had vitamin D insufficiency. Vitamin D deficiency was associated with 2.6-fold increased risk for COVID-19 (OR = 2.6; [95% CI 1.96-4.9]; P = 0.002. The FokI FF genotype was significantly more represented in patients compared to control group (OR = 4.05; [95% CI: 1.95-8.55]; P < 0.001). CONCLUSIONS: Vitamin D deficiency and VDR Fok I polymorphism may constitute independent risk factors for susceptibility to COVID-19 in Egyptian children and adolescents. IMPACT: Vitamin D deficiency could be a modifiable risk factor for COVID-19 in children and adolescents because of its immune-modulatory action. To our knowledge, ours is the first such study to investigate the VDR Fok I polymorphism in Caucasian children and adolescents with COVID-19. Vitamin D deficiency and the VDR Fok I polymorphism may constitute independent risk factors for susceptibility to COVID-19 in Egyptian children and adolescents. Clinical trials should be urgently conducted to test for causality and to evaluate the efficacy of vitamin D supplementation for prophylaxis and treatment of COVID-19 taking into account the VDR polymorphisms.

COVID-19 associated mucormycosis in Assiut University Hospitals: a multidisciplinary dilemma.

Mucormycosis is a life-threatening opportunistic angioinvasive fungal infection. We aimed to describe the frequency, presentations, predictors, and in-hospital outcome of mucormycosis patients in the scope of CoronaVirusDisease-19 (COVID-19) during the third viral pandemic wave. This cross-sectional retrospective study included all patients who fulfilled the criteria of mucormycosis with concurrent confirmed covid19 infection admitted to Assuit University Hospital between March 2021 and July 2021. Overall, 433 patients with definite covid-19 infection, of which 33 (7.63%) participants were infected with mucormycosis. Mucormycosis was predominantly seen in males (21 vs. 12; p = 0.01). Diabetes mellitus (35% vs. 63.6%; p < 0.001), hypertension (2% vs.45.5%; p 0.04), and Smoking (26.5% vs. 54.5%; p < 0.001) were all significantly higher in mucormycosis patients. Inflammatory markers, especially E.S.R., were significantly higher in those with mucormycosis (p < 0.001). The dose of steroid intake was significantly higher among patients with mucormycosis (160 mg vs. 40 mg; p < 0.001). Except for only three patients alive by residual infection, 30 patients died. The majority (62%) of patients without mucormycosis were alive. Male sex; Steroid misuse; D.M.; Sustained inflammation; Severe infection were significant risk factors for mucormycosis by univariate analysis; however, D.M.; smoking and raised E.S.R. were predictors for attaining mucormycosis by multivariate analysis.

Efficient implementation of optical scanning holography in cancelable biometrics.

This paper presents a new trend in biometric security systems, which is cancelable multi-biometrics. In general, traditional biometric systems depend on a single biometric for identification. These traditional systems are subject to different types of attacks. In addition, a biometric signature may be lost in hacking scenarios; for example, in the case of intrusion, biometric signatures can be stolen forever. To reduce the risk of losing biometric signatures, the trend of cancelable biometrics has evolved by using either deformed or encrypted versions of biometrics for verification. In this paper, several biometric traits for the same person are treated to obtain a single cancelable template. First, optical scanning holography (OSH) is applied during the acquisition of each biometric. The resulting outputs are then compressed simultaneously to generate a unified template based on the energy compaction property of the discrete cosine transform (DCT). Hence, the OSH is used in the proposed approach as a tool to generate deformed versions of human biometrics in order to get the unified biometric template through DCT compression. With this approach, we guarantee the possibility of using multiple biometrics of the same user to increase security, as well as privacy of the new biometric template through utilization of the OSH. Simulation results prove the robustness of the proposed cancelable multi-biometric approach in noisy environments.

Construction and Standardization of Dementia Arabic Scale.

PURPOSE: Validated diagnostic scales for dementia in Arabic are still scarce. The aim of this study is to construct a standardized dementia scale for dementia diagnosis among the Arabic-speaking population. PATIENTS AND METHODS: Construction of the Dementia Arabic Scale (DAS) was done, followed by evaluation of content validity. A pilot study was done to ascertain feasibility and language clarity used in the scale. Patients diagnosed to have major neurocognitive disorder according to DSM-V criteria and control group were subjected to DAS, mini-mental state examination (MMSE) and Cognitive Abilities Screening Instrument (CASI). Finally, standardization of the scale and estimation of cutoff point, sensitivity, specificity, positive predictive value and negative predictive value of the newly constructed scale (DAS) were done. RESULTS: There is significant correlation between DAS and both MMSE and CASI on Pearson's correlation study. The internal consistency of the DAS scale was good, with Cronbach's alpha correlation coefficient of 0.88. At cut-off ≤95 for literate, and ≤68 for illiterate, the sensitivity of the DAS scale was 100%, 87% for literate and illiterate, respectively, while specificity was 84%, 96% respectively, with an area under the receiver operating characteristic curve of (AUC) 0.96. CONCLUSION: The DAS scale is an acceptable, reliable and valid scale for the diagnosis of dementia in Arabic-speaking countries.

Conventional peritoneal cytology lacks the prognostic significance of detecting local or peritoneal recurrence in colorectal cancer: An Egyptian experience.

BACKGROUND AND AIM: Colorectal cancer (CRC) accounts for over 8% of all deaths each year, with 1.2 million new cases diagnosed annually worldwide. It represents the seventh most common cancer in Egypt. Early detection of peritoneal metastasis is a major challenge in such cases. It helps with the decision of the immediate application of intraperitoneal chemotherapy after resection. Meta-analysis studies reported contrast evidence for a possible prognostic role of intraperitoneal free cancer cells (IPCCs) in peritoneal recurrence and survival after curative resection. In this work, we aim to evaluate the prevalence and impact of detecting free malignant cells in peritoneal fluid on survival and local recurrence and to estimate the incidence of peritoneal carcinomatosis (PC) during follow up. METHODS: Design: This was a prospective cohort study. Settings: From June 2016 to December 2018, samples were collected from 104 patients who underwent abdominal surgery for colorectal cancer in the Egyptian National Cancer Institute. A total of 96 Egyptian CRC patients who underwent curative resection were enrolled. Intraoperative peritoneal lavage was performed to detect IPCC by conventional cytology. Patients with no residual tumor after surgery and no evidence of PC were followed up for a median 14 months. The cumulative 12-month overall survival rate for patients with IPCC was 100% versus 86% for patients with negative cytology. RESULTS: Our results demonstrated that the prevalence of IPCC in the peritoneal lavage was 11.5%. Peritoneal and local recurrence occurred at a higher rate in patients with cytology positive lavage (9.1% vs 6.3% and 9.1% vs 3.8%, respectively), although this was statistically insignificant. Distant metastasis occurred significantly in patients with positive cytology (45.5% vs 8.9%) with P-value <0.001.The conventional cytology technique has a high specificity but less sensitivity. CONCLUSIONS: The presence of IPCC using conventional cytology was not an independent prognostic factor for the development of PC or survival.

Relation between left atrial strain and exercise tolerance in patients with mild mitral stenosis: An insight from 2D speckle-tracking echocardiography.

BACKGROUND: Mild mitral stenosis (MS) is a progressive disease but unfortunately, its clinical course is still unclearly studied. We aimed to study the left atrial (LA) deformation in such patients and how it is related to exercise intolerance. METHODS: Seventy-five patients with mitral valve area of 1.81 ± 0.13 cm2 and 40 healthy control subjects were enrolled. All participants had sinus rhythm, and they underwent conventional echocardiography and LA strain analysis with speckle-tracking study. The following parameters were obtained: left atrial reservoir strain (LAS-s), LA conduit strain (LAS-e), and LA contraction strain (LAS-a). All participants underwent symptoms limited stress ECG using modified Bruce protocol. RESULTS: Comparing with control subjects, patients with mild MS had significant lower LAS-s value (P < .01) and LAS-e (<0.03). Patients with exercise intolerance (METs < 8) had lower LAS-s (P < .001), LAS-e (P < .01), and LAS-a (P < .05) values compared to those with METs ≥ 8. We found that METs was significantly related to LAS-s (P < .001), brain natriuretic peptide (P < .001), and Δ TAPSE (P < .03). Multivariate analysis showed that LAS-s was an independent predictor of reduced exercise capacity. With ROC analysis, LAS-s ≤ 26.5% was the optimal value for prediction of exercise intolerance in patients with mild MS. CONCLUSION: A significant percentage of patients with mild mitral stenosis had exercise intolerance. We found that LAS-s was significantly associated with exercise capacity in patients with mild MS. Hence, we thought that LA deformation could be of great value in the follow-up of patients with mild MS.

Laparoscopic gastrectomy with D2 lymphadenectomy for gastric cancer: initial Egyptian experience at the National Cancer Institute.

BACKGROUND: Laparoscopic gastrectomy has been used as a superior alternative to open gastrectomy for the treatment of early gastric cancer. However, the application of laparoscopic D2 lymphadenectomy remains controversial. This study aimed to evaluate the feasibility and outcomes of laparoscopic gastrectomy with D2 lymphadenectomy for gastric cancer. RESULTS: Between May 2016 and May 2018, twenty-five consecutive patients with gastric cancer underwent laparoscopic D2 gastrectomy: eighteen patients (72%) underwent distal gastrectomy, four patients (16%) underwent total gastrectomy, and three patients (12%) underwent proximal gastrectomy. The median number of lymph nodes retrieved was 18 (5-35). A positive proximal margin was detected in 2 patients (8%). The median operative time and amount of blood loss were 240 min (200-330) and 250 ml (200-450), respectively. Conversion to an open procedure was performed in seven patients (28%). The median hospital stay period was 8 days (6-30), and the median time to start oral fluids was 4 days (3-30). Postoperative complications were detected in 4 patients (16%). There were two cases of mortality (8%) in the postoperative period, and two patients required reoperation (8%). CONCLUSIONS: Laparoscopic gastrectomy with D2 lymphadenectomy can be carried out safely and in accordance with oncologic principles.

Biallelic mutations in SORD cause a common and potentially treatable hereditary neuropathy with implications for diabetes.

Here we report biallelic mutations in the sorbitol dehydrogenase gene (SORD) as the most frequent recessive form of hereditary neuropathy. We identified 45 individuals from 38 families across multiple ancestries carrying the nonsense c.757delG (p.Ala253GlnfsTer27) variant in SORD, in either a homozygous or compound heterozygous state. SORD is an enzyme that converts sorbitol into fructose in the two-step polyol pathway previously implicated in diabetic neuropathy. In patient-derived fibroblasts, we found a complete loss of SORD protein and increased intracellular sorbitol. Furthermore, the serum fasting sorbitol levels in patients were dramatically increased. In Drosophila, loss of SORD orthologs caused synaptic degeneration and progressive motor impairment. Reducing the polyol influx by treatment with aldose reductase inhibitors normalized intracellular sorbitol levels in patient-derived fibroblasts and in Drosophila, and also dramatically ameliorated motor and eye phenotypes. Together, these findings establish a novel and potentially treatable cause of neuropathy and may contribute to a better understanding of the pathophysiology of diabetes.

Author Correction: Biallelic mutations in SORD cause a common and potentially treatable hereditary neuropathy with implications for diabetes.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A Comparison of Zirconia and Titanium Abutments for Microleakage.

BACKGROUND: Microleakage through the interface has been documented in implant systems with titanium (Ti) abutments. There is a current increase in the use of zirconia (Zi) abutments especially in esthetic zone in where higher risk of visible metal color through the peri-implant tissues exists. PURPOSE: The aim of the present in vitro study is to evaluate the leakage at the implant fixture-abutment interface with two different screw-retained abutment systems at different torque values in a nonloading condition. MATERIALS AND METHODS: In vitro study design included four groups (Ti and Zi torqued at 25 and 15 Ncm [N = 8/group]). Microcomputed tomography (micro-CT) was chosen to detect microgap. Microleakage from the implant chamber to the external milieu was evaluated using limulus amebocyte lysate (LAL) test, while microleakage from external milieu to the implant chamber was evaluated using toluidine blue dye (TBD) and colorimeter. RESULTS: Micro-CT images did not reveal any microgap. LAL test showed that there is a time-, abutment-, and torque-dependent increase in microleakage (p = .001) with Zi torqued at 15 Ncm having higher leakage with time compared with Ti torqued at 15 Ncm (p = .002), as well as Zi torqued at 15 Ncm having higher leakage with time compared with Zi torqued at 25 Ncm (p = .01). TBD test showed a nonsignificant increase in microleakage with higher leakage related to titanium abutment groups (p > .05). Repeated torque/antitorque handling differentially affected microleakage (p = .01). CONCLUSIONS: Within the limits of this study, there is a statistically significant difference in bidirectional microleakage with time, abutment type, and torque values being major players for leakage from internal implant chamber to external milieu, while the abutment type and time but not the torque value being important factors for leakage from external milieu into implant chamber in nonloading condition. Future studies are needed to determine peri-implant health around Zi abutments.