The importance of upper first permanent molars position for the orthognatic occlusion

Development of the dental arches and occlusion in permanent dentition can be divided into several stages and has to be observed regularly. The first permanent molar eruption is related to the onset of significant changes in the developing occlusion. Although this tooth is seen as the `key to occlusion` its value as an anchorage is debatable.The aim of the article is to study the correct position of the upper first molars in the two planes of space - the sagittal and transverse planes.In this article the position of the first upper molar is examined with the aid of diagnostic records, such as study cast, orthopantomogram (OPG), and lateral cephalometrics. A literature review includes Bulgarian and foreigner authors.Angle, who in 1899 referred to the maxillary first permanent molars as the `key to occlusion`, was the first to mention their importance within the dentition. According to Angle, the line passing through the middle of the mesiobuccal cusp of the upper first molar coincides with the line passing through the buccal groove of the lower first molar. After Angle, other authors have discussed the position of upper molars from different point of view, such as their relation or position in the maxilla, anteroposterior axial inclination and rotation. As indicated by Lamons and Holmes molar rotations commonly exist in Class II malocclusions. The molars are usually rotated around an axis lingual to their central fossae. In an ideal occlusion the buccal surfaces of the upper first molars are usually parallel to each other.On the OPG Kurol and Bjerklin measured the axial mesial inclination of upper first molar. The tipping of the molars is measured by the angle formed between the tangent line to the mesial surfaces of the root and crown and the line through the lower margins of the left and right orbits.According to Sassouni, the mesial contour of upper first molar should to lie on the 4th arc - the temporal arc. If the molar is anterior to this arc, a treatment with distalization could be initiated. The temporal arcnasion distance measured on the radius is equal to the distance from point ANS to the upper first molar. The position of the upper first molar varies with the position of the upper central incisors. The basic hypothesis is that if the upper first molar has a fixed position in the face, any increase in the total upper dental arch length will be transferred to the incisor area. Any change in the anteroposterior position of the upper first molar could influence the position of the mandibular- leading to Class II malocclusion.Ricketts pointed out that the average distance from the pterygoid vertical (PTV) to the distal surface of upper first molar is the sum of the age of the patient + 3mm, in a growing patient. This diagnostic method can help the orthodontist to decide whether to extract teeth or to distalize the molars.Any loss of space in the arch is a justification for early orthodontic treatment. Mediopalatal rotation of the upper molar is an additional problem in the final phase as well. The rotation of upper first molars is measured by the angles formed by the intersection of lines going over the tips of the mesiopalatal and distobuccal cusps of each molar (Ricketts line) with a straight line marked over the palatine raphe.The problem of reduced arch length has an impact on the final treatment stage when the major orthodontic goal is establishing a tight teeth intercuspation. The molars influence the transfer of occlusal forces to the facial skeleton. The upper first molar tolerates more changes in the position than the lower one. The correct position of the upper molar ensures a stable occlusion with significantly low grade of relapse

Phytosanitary Status of Wheat Crops in Northeastern Bulgaria

In the present work, the results of a survey of wheat crops in the area of the IASS quot%253BObraztsov chiflikquot%253B ndash%253B Ruse are presented. The study was carried out during the period 2018-2021, at the experimental field of the institute, according to accepted methods for weed infestation, species composition of the entomofauna and economically important wheat diseases. The aim of the study is to determine the species composition of weeds, diseases and insect pest in wheat crops under the relevant agro-climatic conditions. Weed species composition differed by year, with a total of 15 weed species from 10 families recorded. Veronica agrestis L., Lamium purpureum L., Anthemis arvensis L., Convolvulus arvensis L. and Cirsium arvense L. are ubiquitous in surveyed crop. Insects belonging to the orders Coleoptera, Diptera, Hemiptera, Homoptera, Hymenoptera, Lepidoptera, Neuroptera and Orthoptera were identified. The proportion of the orders to which the species belonged in the three years of the study differed in culture. The total number of insects detected during the three years of the test varied on average (CV%253D15.63%25) ndash%253B 373 pcs. in 2019, 280 pcs. in 2020 and 372 pcs. in 2021. During the period, 3 fungal pathogens of the genera Puccinia, Erysiphe and Septoria were identified. The development of Puccinia and Erysiphe pathogens during the study period was within acceptable limits according to the SEV scale (from 10%25 to 25%25). Massive development of the pathogen Septoria sp. was observed, with the affected plant area reaching up to 65%25, according to the SEV scale

Culture-Dependent Approach for Determining Microbial Diversity in Soils from KCM/AGRIA Region

Significant shifting of the microbial communities structure was detected in three metal-polluted soils collected around the Pb-Zn smelter KCM and the agrochemicals factory AGRIA, situated near the town of Plovdiv, Bulgaria. Industrial-, dumpsite- and agricultural soils were contaminated with As: 7.5-52.9 mg/kg; Hg: 0.086-0.404 mg/kg; Cd: 2.3-71.1 mg/kg; Mn: 742-1510 mg/kg; Pb: 138-2560 mg/kg; Cu: 32-268 mg/kg and Zn: 293-4490 mg/kg. Remarcable ecological disturbance was found in the agricultural soil using ecotoxicological test with type strain Pseudomonas putida DSM 50026 (ISO 10712). In order to assess ecologically relevant bacteria over twenty soil bacterial isolates were cultured. Six of them possess tolerance to one or more heavy metals. Four of the isolates demonstrated herbicide tolerance to 2,4-dichlorphenoxiacetic acid. Our results suggest that the microbial community responds to long-term metal- and pesticides contamination through changes in microbial community structure and selection for resistance. *** and.

The influence of socio-demographic characteristics on maxillary first molar derotation in children with mixed dentition

Естетиката и стабилният резултат са крайна цел на всяко ортодонтско лечение. В основата на стабилния резултат стои ортогнатната оклузия и идеалната зъбна дъга. Постигането на този резултат се влияе и от правилно проведената първична и вторична профилактика още от ранно смесено съзъбие.Целта на настоящото изследване е да се направи социодемографска характеристика на деца с изменения в ротацията на горен първи молар при смесено съзъбие.Материал и методи: Изследвани са общо 681 деца на възраст между 7 и 10 г. Ротацията на горния първи молар е измерена според методите на Frie, Henry и Vigano и резултатите са представени според пол, възраст и големината на ротация на горните първи молари според зъбния клас при молари. Резултатите са обработени статистически, като са използвани дескриптивен, вариационен и сравнителен анализ.Резултати и обсъждане: Статистически значима разлика беше намерена по отношение на показателя пол, като при момичетата се наблюдава по-съществено ротиране на горните първи молари в сравнение с ротацията при момчетата. И при десните, и при левите молари момичетата са с по-голяма ротация на моларите. Не беше намерена съществена разлика според възрастовия показател въпреки вариациите в ротацията. Най-често срещана е двустранната медиопалатинална ротация на горните първи молари.Заключение: Възрастта на децата не се явява фактор при ротирането на горните първи молари. От друга страна полът е показател при ротирането на горните първи молари, като при момичетата се констатира по-голямо ротиране в сравнение с момчетата.Esthetic facial appearance and long-term stability of normal occlusion are the major goals of orthodontic treatment. Meeting these goals is based on orthognathic occlusion and a well-aligned arch. The accomplishment of these goals depends on proper and well-timed prophylaxis performed in early mixed dentition.AIM: The purpose of this study was to evaluate the influence of socio-demographic characteristics on maxillary first molar rotation in mixed dentition.MATERIALS AND METHODS: The sample included 681 untreated patients aged 7-10 years who were evaluated with the aid of the Friel Henry and Vigano analysis methods for assessment of the magnitude of maxillary molar rotation. The results were summarized and presented by gender, age and dental class. Then they were processed statistically by using descriptive, variation and comparative analysis.RESULTS AND DISCUSSION: Statistically significant difference was observed in this study in two groups divided by gender - the incidence of upper first molar rotation is higher in girls than in boys regardless of the side - left or right. No significant impact of age on molar rotation was observed. The most frequently established malposition is bilateral mediolingual rotation of the upper permanent first molars.CONCLUSION: It appears that age is not a factor influencing maxillary permanent first molars but the gender is an important factor to be considered. The incidence of rotation is higher in girls than boys

Investigation of Biological and Prooxidant Activity of Zinc Oxide Nanoclusters and Nanoparticles

Zinc oxide (ZnO) nanomaterials offer some promising antibacterial effects. In this study, a new form of ZnO is synthesized, named ZnO nanocluster bars (NCs). Herein, ZnO NCs, ZnO nanoparticles (NPs), ZnO coated with silica (ZnO-SiOA, ZnO-SiOB), and SiO2 NPs were prepared, characterized, and their antimicrobial and prooxidant activity were tested. The prooxidant activity of all nanomaterials was studied according to free-radical oxidation reactions (pH 7.4 and pH 8.5) in chemiluminescent model systems. Each form of new synthesized ZnO nanomaterials exhibited a unique behavior that varied from mild to strong prooxidant properties in the Fenton`s system. ZnO NPs and ZnO NCs showed strong antibacterial effects, ZnO-SiOA NPs did not show any antibacterial activity representing biocompatibility. All tested NMs also underwent oxidation by H2O2. ZnO NCs and ZnO NPs exhibited strong oxidation at pH 8.5 in the O2-. generating system. While, SiO2, ZnO-SiOA andZnO-SiOB possessed pronounced 60-80% antioxidant effects, SiO2 NPs acted as a definitive prooxidant which was not observed in other tests. ZnO NCs are strong oxidized, assuming that ZnO NCs provide a slower release of ZnO, which leads to having a stronger effect on bacterial strains.  Thus, ZnO NCs are an important antibacterial agent that could be an emergent replacement of traditional antibiotics

Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three genomic nomenclature systems to all sequence data from the World Health Organization European Region available until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation, compare the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2

Antibacterial activity of thin films TiO2 doped with Ag and Cu on Gracilicutes and Firmicutes bacteria

Antibacterial activity of thin films TiO2 doped with Ag and Cu on Gracilicutes and Firmicutes bacteri

Antibacterial activity of thin films TiO2 doped with Ag and Cu on Gracilicutes and Firmicutes bacteria

Antibacterial activity of thin films TiO2 doped with Ag and Cu on Gracilicutes and Firmicutes bacteri

MONITORING OF CMV INFECTION IN KIDNEY TRANSPLANT RECIPIENTS

Human cytomegalovirus is a ubiquitous herpesvirus that establishes lifelong latency after primary infection, but can cause life-threatening disease in immunosuppressed patients. CMV invasive disease leads to significant morbidity and mortality following kidney transplantation. We tested 2 groups of patients - Group A included 20 potential kidney recipients and 29 potential donors investigated by ELISA and Group B included 53 adult kidney transplant recipients all of them tested in ELISA and 24 of them tested in QRT-PCR for CMV-DNA from plasma samples. In group A 16 (80%) of 20 potential kidney recipients were anti-CMV IgG positive and 4 (20%) were anti-CMV IgG negative. Twenty eight of 29 potential donors were found seropositive, and only one was not infected. In group B overall 119 ELISA tests for specific anti-CMV antibodies were performed. Anti-CMV IgM negative was 68 (57%) of the tested samples, twelve (10%) showed anti-CMV IgM equivocal results and 39 samples (33%) were with anti-CMV IgM positive. Seven of them (13,2%) showed repeatedly anti CMV IgM positive results. All 119 (100%) displayed аnti-CMV IgG positive results. Overall 41 PCR analyses from plasma samples of 24 kidney transplant recipients (group B) were performed. CMV-DNA replication was detected in 5 plasma samples obtained from 3 patients (12.5%) at a different time - from 20 days till almost 8 years after the transplantation. Despite the high seroprevalence to CMV 20% of the potential recipients were at high risk of primary infection when receiving a kidney from a seropositive donor. Positive serological results during the regular post-transplantation monitoring complemented with or without clinical data are indicative and require further QRT-PCR analysis