Effect of slice thickness of 3D printer in fabrication of surgical guide on the accuracy of dental implant placement.

Introduction This study aimed to assess the effect of slice thickness of 3D printer in fabrication of surgical guide (SG) on the accuracy of dental implant placement. Materials and Methods After preparation of two dry human mandibles, Cone-beam computed tomography (CBCT) scans were obtained, and the location and direction of implants in the edentulous ridge of the mandible were identified using Romexis software. Data in STL format were transferred to a 3D printer and two SGs with 50 µm and 100 µm thicknesses were fabricated for each mandible. Drilling was performed using two SGs. The pre- and post-intervention CBCT scans were superimposed to measure the magnitude of differences. The two groups were compared using the Mann-Whitney U test. Results No significant difference was noted in SGs with 50 and 100 µm thicknesses in the coronal and apical regions of the implants or the depth of drilling. However, the difference in angular deviation was statistically significant. Conclusion Considering the higher accuracy of SGs with 50 µm thickness (despite the presence of a significant difference in AD between the SGs with different thicknesses), it is recommended to use a SG with 50 µm thickness in cases where anatomical limitations exist.

COVID-19-associated mucormycosis involving the maxilla.

It is important to increase the awareness and knowledge of head and neck surgeons about the recent surge of craniofacial mucormycosis in COVID-19 patients because early diagnosis and appropriate treatment are essential to improve the outcomes. Here, we describe clinical features, treatment protocols, and outcomes of treatment in eight patients with COVID-19-associated mucormycosis in the maxilla. Consistent with the findings of previous studies, our experience in the management of these eight patients shows that early administration of amphotericin B and prompt aggressive surgery are essential for optimal control of the disease.

Source apportionment and health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the coastal ecosystem of the Brunei Bay, Brunei.

Pollution characteristics and associated ecological risks of PAHs in sediments from Brunei Bay, Brunei were investigated. The concentrations of ∑16 PAHs ranged from 826.7 to 2955.3 µg kg-1, indicating moderate to high level of pollution. Source apportionment of PAHs by molecular isomeric ratios and positive matrix factorization model indicated impact of potential anthropogenic PAH sources including combustion of biomass and fossil fuels. The data indicated relatively no significant ecotoxicological risk for most of PAH compounds. To estimate the individual c-PAH toxicity, the toxic equivalent quantity (c-TEQ) was calculated. Results of the TEQ analysis showed that BaP followed by DBA and BaA are the most carcinogenic of PAHs examined in the study area. The evaluation of human health risk of PAHs revealed that the cancer risk of PAHs for adults and children was higher than the USEPA threshold (<1E-06) and lower than 1E-3, implying low to moderate risk.

Bone mineral density and muscle mass in adults with developmental skeletal discrepancies.

BACKGROUND: It was aimed to investigate the musculoskeletal status in individuals diagnosed with skeletal discrepancies. METHODS: This case-control study was performed on 35 patients with developmental skeletal discrepancies listed for orthognathic surgery as a case group and 33 patients who were nominated for wisdom tooth removal as a control group. All participants were aged 18-40 years and the research was carried out in the period between May 2018 and May 2019. Dual X-ray absorptiometry (DEXA) was used to assess bone mass density at three bone sites: total hip, femoral neck, and the spinal lumbar vertebrae (L1-L4). The appendicular muscle mass index (ASMI) was measured based on the four limbs from the DEXA scan. RESULTS: Our data showed that 45.7% (16) of the case group were osteopenic or osteoporotic while in the control group only 21.2% (7) were osteopenic in at least one region (total hip, femoral neck, or lumbar) (p-value = 0.03). Regarding muscle mass, there was significantly lower SMI in subjects with skeletal discrepancies (case group) compared with the control group (median (IQR) 5.9 (2.5) vs. 6.8 (2.9) (kg/m2), respectively, p = 0.04). CONCLUSIONS: There is an essential need for more studies to understand the exact interrelationship between musculoskeletal status and skeletal jaw discrepancies.

Dietary vitamin C in pre-parturient dairy cows and their calves: blood metabolites, copper, zinc, iron, and vitamin C concentrations, and calves growth performance.

The aim of this study was to evaluate the effects of dietary vitamin C supplementation on blood parameters of pre-parturient (PP) dairy cows and growth performance and immune system of their newborn calves. Forty PP cows (at approximately 21 days before calving and an average weight 791 ± 50 kg) were allocated into two experimental treatments: (1) basal diet without vitamin C supplementation (CO) and (2) basal diet with 20 g of vitamin C supplementation from 21 days before calving to parturition (VC). After parturition, the experiment continued by grouping the calves into four dietary treatments with 8 calves in each treatment. The experimental treatments were (1) control calves with no vitamin C supplementation and from cows that received no vitamin C supplement (CON), (2) calves supplemented with 600 mg of vitamin C per day and from cows that received no vitamin C supplement (CVC), (3) calves supplemented with no vitamin C and from cows that received 20 g of vitamin C per day (MVC), and (4) calves supplemented with 600 mg of vitamin C per day and from cows that received 20 g of vitamin C per day (CMVC). Serum concentrations of glucose, HDL and LDL, cholesterol, triglycerides, total protein, and albumin of cows were not affected by vitamin C supplementation during pre-parturient period. However, cows that received VC diet had lower (P < 0.05) malondialdehyde (MDA) and aspartate aminotransferase (AST) concentrations, higher total antioxidant capacity (TAC), and vitamin C concentration in their blood compared to CO cows. Vitamin C supplementation had no effect on plasma iron, copper, and zinc concentrations of PP cows. Similarly, vitamin C supplementation had no effect on total feed intake and feed conversion ratio (FCR) of suckling calves. However, calves in the CMVC group had higher (P < 0.05) overall daily weight gain compared to the other groups. Calves in the CVC and CMVC groups had lower (P < 0.05) blood MDA concentration on days 7 and 21. The highest (P < 0.05) blood TAC level was recorded in CMVC calves. Control group calves had lower (P < 0.05) blood superoxide dismutase activity compared to the other calves. Blood levels of alanine aminotransferase on days 7 and 21 and aspartate aminotransferase on day 7 were higher (P < 0.05) for calves in the CON and MVC groups. Based on the results, vitamin C supplementation had positive health effects on the oxidative parameters of PP dairy cows and also improved the performance and health status of the calves.

Intraoral transnasal approach for surgical extraction of bilateral deeply impacted mesiodens: A case report.

We describe a novel modified intranasal approach to minimize the complications of the impacted mesiodens surgical extraction. Also, it can be performed under local anesthesia with proper preoperative workup.

Non-traumatic myositis ossificans of the Right masseter muscle: a case report and review of the literature.

Myositis ossificans (MO) is a rare disease in which ossification develops in the muscle or soft tissue. MO traumatica is recognized by ossification of the soft tissues after acute or repetitive trauma, burns, or surgical procedures. It usually involves the extremity muscles. In the head and neck region, the masseter is most commonly involved in MO traumatica. Surgical resection of the ossified tissue has been the most commonly used treatment for this disorder, with a high postoperative recurrence rate. We report a case of non-traumatic MO of the Masseter muscle with different size round calcifications and to review the literature reported data about MO traumatica involving the masseter muscle.

Bioavailability, distribution and health risk assessment of arsenic and heavy metals (HMs) in agricultural soils of Kermanshah Province, west of Iran.

Kermanshah Province as an agricultural hub exports food crops to neighboring countries. In this study, contamination status, bioavailability, spatial distribution, and ecological and human health risk of arsenic and heavy metals (HMs) in soil were investigate. For this purpose, 121 agricultural soil samples were collected and analyzed using ICP-MS. The data were studied by calculating some geochemical indices, and using geographical information system and statistical analysis. Results showed that Cd has the highest bioavailability, following by Cu and As. Also, Cu was severely associated with organic matter. Enrichment factor (EF) followed the order of As > Cu > Pb > Se > Cd > Zn > Ni > Cr, and the soil pollution index (SPI) ranged from 0.82 to 2.65. Low potential ecological risk was measured for most of the samples. However, Kermanshah County and Eastern parts of the Province showed the highest HMs enrichment and ecological risk. Moreover, high carcinogenic risk of Cr and Ni threatens the children. Cr showed also high non-carcinogenic hazard index (HI) for children. Principal component analysis (PCA) indicated the anthropogenic origins for As, Cd, Cu, Pb, Se and Zn, while Cr and Ni originated mainly from a geogenic source. Furthermore, Kruskal-Wallis H test revealed that As, Cd, Cr, Cu, Ni, Pb, Se and Zn concentrations were significantly different (p < 0.05) between 16 Counties of the Kermanshah Province. Overall, the management of urban and industrial contamination sources is required to minimize the concentration of bioavailable portion of HMs and preventing residents of the area from being exposed to contaminants.

Displacement of the third molar bud to the sublingual space during open reduction and internal fixation of mandibular angle fracture: A case report.

This case could remind surgeons to consider the possibility of displacement of the impacted third molar in the fractured line to adjacent spaces, during open reduction and internal fixation of mandibular angle fracture.

Self-regeneration of an extensive bony defect following mandibular resection.

Spontaneous bone regeneration is a rapid and uncommon formation of new bone in a previous bone defect. Preservation of periosteum as the main source of osteogenesis, young age, and genetics are possible important factors related to this phenomenon.

Effect of Slow-Release Pellets of Selenium and Iodine on Performance and Some Blood Metabolites of Pregnant Moghani Ewes and Their Lambs.

The need for minerals during pregnancy in mammals increases by progress of gestation due to embryo development. Therefore, the supply of trace minerals for pregnant ewes in late pregnancy may be of vital importance. The present study was carried out to evaluate the effect of selenium and iodine release slowly on the performance and some blood parameters of pregnant ewes and their lambs. Experiments were performed on 40 pregnant ewes from 3 to 4 years old in the last month of pregnancy with a weighing average of 52 ± 5 kg and a factorial experiment (2 × 2) in a completely randomized design with 4 treatments and 10 replicates used for 120 days (30 days before and 90 days after parturition of ewes). Experimental treatments were containing the following: (1) control, (2) ewe receiving bolus containing iodine, (3) ewe receiving bolus containing iodine and selenium, and (4) ewe receiving bolus containing selenium. One month before the expected birth date, the pellets will be fed to each of the livestock by bolus gun. During the test period, ewes will not receive any other mineral supplements and will be kept in a group in a herd. Ewes were blood sampled at 10 days prepartum and 30 and 60 days postpartum. The results showed that body weight on birth and weaning of lambs and average daily gain of lambs were highest in bloused animals that were related to the slow-release selenium tablet lambs (P < 0.05). Lambs born to mothers receiving 0.3 mg day-1 of selenium per day had a keratin phosphokinase concentration of T4 concentration and T4 to T3 lower than that of zero selenium (P < 0.05). Daily gain, glutathione peroxidase activity, and T4 concentration at iodine 0.4 mg day-1 were significantly higher than iodine level (P < 0.05). The adding of slow- release pellets of iodine and selenium improved the immune system.

Molecular genetic study of glutaric aciduria, type I: Identification of a novel mutation.

Glutaric acidemia type I (GA-1) is an inborn error of metabolism due to deficiency of glutaryl-CoA dehydrogenase (GCDH), which catalyzes the conversion of glutaryl-CoA to crotonyl-CoA. GA-1 occurs in about 1 in 100 000 infants worldwide. The GCDH gene is on human chromosome 19p13.2, spans about 7 kb and comprises 11 exons and 10 introns. Tandem mass spectrometry (MS/MS) was used for clinical diagnosis in a proband from Iran with GA-1. Sanger sequencing was performed using primers specific for coding exons and exon-intron flanking regions of the GCDH gene in the proband. Cosegregation analysis and in silico assessment were performed to confirm the pathogenicity of the candidate variant. A novel homozygous missense variant c.1147C > A (p.Arg383Ser) in exon 11 of GCDH was identified. Examination of variant through in silico software tools determines its deleterious effect on protein in terms of function and stability. The variant cosegregates with the disease in family. In this study, the clinical and molecular aspects of GA-1 were investigated, which showed one novel mutation in the GCDH gene in an Iranian patient. The variant is categorized as pathogenic according to the the guideline of the American College of Medical Genetics and Genomics (ACMG) for variant interpretation. This mutation c.1147C > A (p.Arg383Ser) may also be prevalent among Iranian populations.

Inferior Alveolar Nerve Medialization for Dental Implant Placement: Case Report with the Introduction of a New Technique.

Inferior alveolar nerve repositioning is an option for treating the edentulous posterior mandible with insufficient bone height above the inferior alveolar canal. This report presents a case in which inferior alveolar nerve medialization was performed for placing dental implants. In the second postoperative week, mandibular fracture occurred after biting on a relatively solid piece of food, which was treated conservatively.

Distribution, source apportionment and health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in intertidal sediment of Asaluyeh, Persian Gulf.

Surface sediment samples were collected from intertidal zone of Asaluyeh, Persian Gulf, to investigate distribution, sources and health risk of sixteen polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations ranged from 1.8 to 81.2 µg kg-1 dry weight, which can be categorized as low level of pollution. Qualitative and quantitative assessments showed that PAHs originated from both petrogenic and pyrogenic sources with slight pyrogenic dominance. Source apportionment using principal component analysis indicated that the main sources of PAHs were fossil fuel combustion (33.59%), traffic-related PAHs (32.77%), biomass and coal combustion (18.54%) and petrogenic PAHs (9.31%). According to the results from the sediment quality guidelines, mean effects range-median quotient (M-ERM-Q) and benzo[a]pyrene toxic equivalents (BaPeq), low negative ecological risks related to PAH compounds would occur in the intertidal zone of Asaluyeh. The total benzo[a]pyrene (BaP) toxic equivalent quotient (TEQcarc) for carcinogenic compounds ranged from 0.01 to 7 µg kg-1-BaPeq, indicating low carcinogenic risk. The human health risk assessment of PAH compounds via ingestion and dermal pathways suggests low and moderate potential risk to human health, respectively.

Polycyclic aromatic hydrocarbons (PAHs) in sediment and sea urchin (Echinometra mathaei) from the intertidal ecosystem of the northern Persian Gulf: Distribution, sources, and bioavailability.

The distribution, sources and bioavailability of polycyclic aromatic hydrocarbons (PAHs) in sediment and sea urchin (Echinometra mathaei) from the intertidal zone of the northern Persian Gulf were investigated. Total PAH concentrations varied from 12.8 to 81.25 and from 16.7 to 35 µgKg-1 dry weight in sediment and Echinometra mathaei, respectively. The PAH concentrations can be classified as low. Source identification and apportionment using diagnostic ratios and principal component analysis demonstrate that the combustion of fossil fuels, road traffic, combustion of natural gas and biomass, and oil spill could be considered as the main sources of PAH contamination. The first PAH biota-sediment accumulation factors (BSAF) data from sediment to Echinometra mathaei in the intertidal zone of the northern Persian Gulf were calculated, indicating accumulation of both lower and higher molecular weight PAHs, with a preferential accumulation of lower molecular weight PAHs.

Ecotoxicological and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Short-Neck Clam (Paphia undulata) and Contaminated Sediments in Malacca Strait, Malaysia.

The distribution, sources, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediment and the edible tissue of short-neck clam (Paphia undulata) from mudflat ecosystem in the west coast of Malaysia were investigated. The concentrations of ∑16 PAHs varied from 347.05 to 6207.5 and 179.32 to 1657.5 ng g-1 in sediment and short-neck clam samples, respectively. The calculations of mean PEL quotients (mean-PELQs) showed that the ecological risk of PAHs in the sediment samples was low to moderate-high level, whereas the total health risk through ingestion and dermal contact was considerably high. The PAHs biota sediment accumulation factors data for short-neck clam were obtained in this study, indicating a preferential accumulation of lower molecular weight PAHs. The source apportionment of PAHs in sediment using positive matrix factorization model indicated that the highest contribution to the PAHs was from diesel emissions (30.38%) followed by oil and oil derivate and incomplete coal combustion (23.06%), vehicular emissions (16.43%), wood combustion (15.93%), and natural gas combustion (14.2%). A preliminary evaluation of human health risk using chronic daily intake, hazard index, benzo[a]pyrene-equivalent (BaPeq) concentration, and the incremental lifetime cancer risk indicated that PAHs in short-neck clam would induce potential carcinogenic effects in the consumers.

The Conservative Treatment of Pediatric Mandible Fracture With External Nasal Splint.

INTRODUCTION: The frequency of mandible fractures is relatively less in children compared with adults, but their treatment is significantly more challenging due to the concerns regarding mandible growth and the developing dentition. The authors have introduced a new way of closed reduction by using external nasal splints. METHODS: In 3 patients aged between 4 and 6-year old with parasymphyseal and body fractures of mandible, fractures were reduced under general anesthesia and thermoplastic nasal splints were directly formed and trimmed to fit the lingual surface of mandible.Splints were fixed to mandible with circummandibular wiring and were retained in place for 3 weeks. RESULTS: All fractures healed uneventfully and the occlusion in all patients was satisfactory. All patients gained good masticatory efficiency. There was no need to use the intermaxillary fixation in any of the patients. CONCLUSION: Using thermoplastic external nasal splint for fracture stabilization in children is an easy, rapid, nonexpensive, and conservative way to treat mandible fractures in pediatric patients.

Mobility and chemical fate of arsenic and antimony in water and sediments of Sarouq River catchment, Takab geothermal field, northwest Iran.

Arsenic (As) and antimony (Sb) concentrations in water and sediments were determined along flow paths in the Sarouq River, Zarshuran and Agh Darreh streams. The results indicate high As and Sb concentrations in water and sediment samples. Raman spectroscopy shows hematite (α-Fe2O3), goethite [α-FeO(OH)] and lepidocrocite [γ-FeO(OH)] in sediment samples. Calculated saturation indices (SI) indicate oversaturation with respect to amorphous Fe(OH)3 for all samples, but undersaturation with respect to Al and Mn mineral and amorphous phases. Therefore, ferric oxides and hydroxides are assumed to be principal mineral phases for arsenic and antimony attenuation by adsorption/co-precipitation processes. The considerable difference between As and Sb concentration in sediment is due to strong adsorption of As(V) into the solid phase. Also, lower affinity of Sb(V) for mineral surfaces suggests a greater potential for aqueous transport. The adsorption of arsenic and antimony was examined using the Freundlich adsorption isotherm to determine their distribution model in water-sediment system and its compatibility with the existing theoretical model. The results showed that the adsorption behavior of both elements complies with the Freundlich adsorption isotherm.

Estimation of deepwater temperature and hydrogeochemistry of springs in the Takab geothermal field, West Azerbaijan, Iran.

Chemical analyses of water samples from 19 hot and cold springs are used to characterize Takab geothermal field, west of Iran. The springs are divided into two main groups based on temperature, host rock, total dissolved solids (TDS), and major and minor elements. TDS, electrical conductivity (EC), Cl(-), and SO4 (2-) concentrations of hot springs are all higher than in cold springs. Higher TDS in hot springs probably reflect longer circulation and residence time. The high Si, B, and Sr contents in thermal waters are probably the result of extended water-rock interaction and reflect flow paths and residence time. Binary, ternary, and Giggenbach diagrams were used to understand the deeper mixing conditions and locations of springs in the model system. It is believed that the springs are heated either by mixing of deep geothermal fluid with cold groundwater or low conductive heat flow. Mixing ratios are evaluated using Cl, Na, and B concentrations and a mass balance approach. Calculated quartz and chalcedony geothermometer give lower reservoir temperatures than cation geothermometers. The silica-enthalpy mixing model predicts a subsurface reservoir temperature between 62 and 90 °C. The δ(18)O and δD (δ(2)H) are used to trace and determine the origin and movement of water. Both hot and cold waters plot close to the local meteoric line, indicating local meteoric origin.