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I DENTI
Quiz by Chiara Di Benedetto
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Comportamenti Sostenibili Insegnare ai bambini l'importanza della sostenibilità è fondamentale per garantire un futuro migliore per il nostro pianeta. Ecco alcuni comportamenti sostenibili che i bambini possono adottare nella vita quotidiana. Ridurre, Riutilizzare, Riciclare Ridurre Consumo di energia: Spegnere le luci quando si esce da una stanza e scollegare i dispositivi elettronici quando non sono in uso. Uso dell'acqua: Chiudere il rubinetto mentre si lavano i denti e fare docce più brevi. Riutilizzare Materiali creativi: Utilizzare scatole di cartone, bottiglie di plastica e altri materiali per progetti artistici. Abbigliamento e giocattoli: Scambiare vestiti e giocattoli con amici o donarli a chi ne ha bisogno. Riciclare Raccolta differenziata: Imparare a separare correttamente i rifiuti e a riciclare carta, plastica e vetro. Compostaggio: Creare un piccolo compost in giardino per scarti di cibo e foglie. Rispetto per la Natura Educazione Ambientale Escursioni: Partecipare a passeggiate nella natura per conoscere flora e fauna locali. Giardinaggio: Coltivare un piccolo orto per comprendere il ciclo di crescita delle piante. Protezione degli Animali Osservazione: Imparare a osservare gli animali senza disturbarli. Alimentazione corretta: Non alimentare gli animali selvatici con cibi inappropriati. Consumo Responsabile Alimentazione Cibo locale e stagionale: Scegliere frutta e verdura di stagione e di produzione locale. Riduzione degli sprechi: Imparare a non sprecare cibo, utilizzando gli avanzi per nuove ricette. Acquisti Prodotti ecologici: Preferire prodotti con imballaggi riciclabili e a basso impatto ambientale. Seconda mano: Acquistare abbigliamento e giocattoli usati. Trasporto Sostenibile Camminare o andare in bicicletta: Scegliere di camminare o andare in bicicletta per brevi distanze invece di utilizzare l'auto. Trasporti pubblici: Utilizzare autobus o treni per ridurre l'impatto ambientale del trasporto privato. Promuovere questi comportamenti sostenibili nei bambini non solo aiuta l'ambiente, ma educa anche le nuove generazioni a prendersi cura del nostro pianeta.Going to the dentist I’m going to the dentist. I’m a little scared. A friendly woman named Jamie asks me to wait. She says I can read, play with toys, or watch a movie. After a few minutes, Dana calls my name. Dana is the dentist’s helper. Dana shows me around the office. She teaches me how to clean my teeth at home. Dana says she will make my teeth super clean. She shows me the tools she will use. Some of the tools look scary, but the cleaning doesn’t hurt. Next, Dana takes special pictures of my teeth. The dentist comes to check my teeth. She looks at the pictures of my teeth. The dentist says I need a filling. I will have to come back another day. I ask if getting the filling will hurt. The dentist says it won’t hurt much because it will be small. The dentist says it’s good we found the problem early. I’m not happy I need a filling, but I’m glad I went to the dentist! Write simple RCQ for beginners: Terrible Toothache NURSE: Good morning, Mr. Croft. MR. CROFT: Good morning, nurse. I want to see the dentist, please. NURSE: Do you have an appointment? MR. CROFT: No, I don't. NURSE: Is it urgent? MR. CROFT: Yes, it is. It's very urgent. I feel awful. I have a terrible toothache. NURSE: Can you come at 10 a.m. on Monday, April 24th? MR. CROFT: I must see the dentist now, nurse. NURSE: The dentist is very busy at the moment. Can you come at 2 p.m.? MR. CROFT: That's very late. Can the dentist see me now? NURSE: I'm afraid that he can't, Mr. Croft. Can't you wait till this afternoon? MR. CROFT: I can wait, but my toothache can't!Sai cosa sono le microplastiche? Quando si parla di microplastiche si fa riferimento a particelle di materiale plastico più piccole di 5 mm, ci sono due tipi di microplastiche ci sono le microplastiche primarie che sono fabbricate di proposito per essere aggiunte ad alcuni prodotti e modificarne le proprie proprietà, per esempio sono presenti in alcuni dentifrici e saponi liquidi sotto forma di granuli abrasivi, ma le ritroviamo anche in diverse prodotti di bellezza dove contribuiscono a creare una sensazione delicata sulla pelle, così come nei bagnoschiuma glitterati. Poi ci sono le microplastiche secondarie, formate dalla frammentazione di materiali di plastica più grande che può venire per effetto degli agenti atmosferici oppure per erosione meccanica, la loro diffusione naturale è provocata dal littering ma anche dall’abrasione degli pneumatici o dei tessuti sintetici come ad esempio i vestiti da sport. Un terzo delle microplastiche presenti nei mari proviene proprio da quest'ultima fonte, si staccano dai vestiti sintetici lavaggio dopo lavaggio; le microplastiche non sono biodegradabili al contrario si accumulano nell'ambiente nel corso del tempo e costituiscono una delle più recenti e pericolose forme di inquinamento ambientale. Le microplastiche primarie insieme frammenti più piccoli delle secondarie finiscono prima o poi nelle stazioni di depurazione delle acque ma non vengono filtrate perché troppo piccole, risultato, finiscono nei laghi negli di oceani, nel mare e anche nel suolo uno studio recente ha dimostrato che le microplastiche sono presenti un po' ovunque e possono anche essere trasportate dalle gocce di pioggia oppure dall'aria e raggiungere così le vette delle montagne oppure le calotte polari. Solo settant'anni fa la plastica non esisteva e ora sta contaminando ogni angolo del pianeta in Europa si stima che più di 40.000 tonnellate di microplastiche inquinano direttamente il mare. Ogni anno lo zooplancton marino può ingerire queste particelle che risalgono così la catena alimentare fino ad arrivare ai mammiferi marini, ai grossi pesci e infine all'uomo. Anche se gli effetti sugli organismi e sulla nostra salute non sono ancora del tutto noti, i primi risultati indicano che potrebbero esserci dei rischi, il fenomeno va quindi trattato con molta attenzione nell’attesa che si trovino delle soluzioni più sostenibili per sostituire le microplastiche ognuno di noi può agire per limitare il fenomeno: 1- smaltimento: smaltire rifiuti di plastica nella maniera giusta consegnandoli nei centri di raccolta e ovviamente non lasciarli in natura dove possono frammentarsi e diventare elementi più piccoli ovvero microclimatiche. 2- usarne meno, ricordate che la plastica migliore è quella che non si usa, evitate di usarla tutte le volte che potete e sostituitela con gli oggetti e materiale riutilizzabili. 3- bucato: cercate di usare detersivi naturali per il bucato, in modo da preservare più a lungo i vestiti sintetici come quelli da sport che altrimenti si degradano più in fretta disperdendo le microplastiche che la lavatrice non è in grado di filtrare. Bene, e ora sai cosa sono le microplastiche?Bonk, the Healthy Monster A candy store has just opened. Bonk has been waiting. He runs inside with money from his piggy bank. "Wow!" he says. "There's cotton candy!" Bonk says. He sees chocolate eggs and rainbow taffy, too. Bonk buys and eats the candy. The next day, Bonk goes to the candy store. "There's root beer!" Bonk says. He sees bubble gum and jelly beans, too. Bonk drinks the soda and blows big bubbles. Day after day, Bonk eats junk food. His piggy bank gets lighter and lighter. But Bonk does not. The candy store owner gives Bonk a balloon. "You are my number one customer," says the owner. Later, Bonk visits the dentist. The dentist looks at Bonk's teeth. "Candy and soda are not healthy for you or your teeth," he says. The weeks pass by with more trips to the candy store. Soon, Bonk can't ride his bike as fast as he did before. Jumping rope is hard work, too. Sometimes, Bonk's tummy hurts. "What should I do?" Bonk asks Lurk and Uzzle. "I know," says Lurk. "Me, too," says Uzzle. Lurk, Uzzle, and Bonk go for a long walk. "You need exercise to be healthy,' says Lurk. They have a picnic of apples, cheese, and fresh brown bread. "You need good food to be healthy, too," says Uzzle. "But what about rainbow taffy and cotton candy?" Bonk asks. "You can have a piece or two," says Uzzle. "I can't have the whole bag?" asks Bonk. "No, never have the whole bag," says Lurk. Bonk's tummy begins to feel better. Soon, he can race his bike and jump rope again. Now, Bonk is not the number one customer at the candy store. But, Bonk is number one at being healthy!Make mcq quiz with 4 option in which one is correct -'10 Basis of Material Science • .....;;;";;;"~~;;,,;;,,,,;.;.,,;;,,,;,,;.;,.,------------ 6. Temporary materials: Some materials are meant to be placed in the oral cavity for a short period of time for different reasons. • Temporary crowns: While a permanent crown is prepared in the dental laboratory, the patient must wait for few days before it can be fabricated and cemented into place. Does patient experience any problems during this time period? If the tooth is vital (the pulp is alive), the patient is likely to experience pain and sensitivity while eating and drinking, also it looks unesthetic. What can be done to solve this problem? A temporary crown is placed before the patient leaves the clinic. It is constructed and luted in the same appointment in which the crown preparation is done. Temporary crowns are not very strong or esthetic but they serve adequately till the permanent crown is ready to be cemented. • Temporary restorations: Sometimes it is difficult to decide immediately the best line of treatment for a particular tooth. The exact condition of the pulp may not be obvious to the dentist from the patient's symptoms. A dentist removes all or part of the decay and then places a temporary restoration to have time to observe the behaviour of the pulp or to give the pilip time to heal before deciding the further treatment required. Classification based on Location of Fabrication 4,9 Materials can be classified based on the location of fabrication into: • Direct restorative materials. • Indirect restorative materials Direct restorative materials: They include those materials which are used to restore cavity preparations directly in the oral cavity (Box 1.5). Box 1.5: Examples of direct restorative materials Amalgam, composites, glass ionomer and other materials, which set by chemical reactions in the mouth. Indirect restorative materials: It includes those restorations which must be fabricated outside the mouth, indirectly on a cast/ model/ die, because their processing condition would harm oral tissues. Materials used in the construction of such prosthesis are called indirect restorative materials (Box 1.6). Box 1.6: Examples of indirect restorative materials Gold inlays, crowns of metal, ceramic and polymers, which are processed at elevated temperatures. Some indirect composite restorations can be processed under specific wavelength of light, e.g. Ceramage. Classification based on Longevity of Use 1. Permanent restorations: These restorations are not planned to be replaced for a particular time period. Though they are referred to as permanent, actually they are not, e.g. fillings, crowns, bridges and dentures do not last forever (Fig. 1.5). 2. Temporary restorations: These restorations are planned to be replaced in a short period of time, such as few days to weeks. For ~ Permanent C/) c c -.2 0 c- :;::; Cll co Interim ~ Q; 0 .8ll::1iJ C/) o~ Cll a:: c:=:J Temporary Time period Fig. 1.5: Diagram depicting the time period of use of a restoration. (Arrow in permanent restoration depicts that such restorations are not planned to be replaced for a long period of time.) Introducton to Dental Materials Dental materials Box 1.7: Characteristics of metals 1. High thermal and electrical conductivity 2. Ductility (pure metals are very soft and they can be bent without breaking) 3. Opacity (they do not transmit light) 4. Luster (they have a surface that strongly reflects light and appears bright and shiny) 5. They tend to dissolve to some extent in water or other aqueous solutions, producing cations. 6. All metals are white (actually gray) except for gold, which is yellow, and copper, which is reddish. 7. All metals are solid at room temperature except mercury, which is liquid at room temperature and is used with silver alloys as amalgam. 8. All metals have high melting temperatures because of high strength of the metallic bond that holds the atoms together. 3. Polymers 4. Composites Composites are mixtures of two or more of the first three classes in which the different components remain distinct from one another in the final structure. A common example is composite resin. Fig. 1.7a: Three-dimensional structure of iron (metal) Metals Metals are the oldest of the three classes of materials that have been used as dental materials. Metals are characterized by metallic bonds (Box 1.7) which will be discussed in the next chapter. Metals solidify with their atoms in a regular or crystalline arrangement (see Chapter 2), often in the form of a cube (Fig. 1.7a). example, temporary fillings done in a tooth during root canal treatment, which have to be replaced within 2-4 days during subsequent visits. They are used to protect the tooth and provide function till the final restoration is done. 3. Interim restoration: At times, dental treatment requires "long-term" definite temporary restorations or "interim" restorations. For examle, a 7-year-old child, met with trauma and fractured one of his central incisors. A large composite build- up may serve his immediate requirement until the root formation is completed and a permanent crown is placed. 5 Classification based on the Chemical Nature of the Material These are the atoms that make up a material and the way they are bonded together determine the properties of that materiaLS Weak bonds make for weak materials and vice versa (Table 1.4). Materials can be classified into different categories based on their primary atomic bonds (Fig. 1.6): 1. Metals 2. Ceramics Fig. 1.6: Classification of dental materials based on chemical nature 12 Basis of Material Science Box 1.9: Benefits of ceramics in dentistry 1. Many ceramic oxides are used as pigmenting agents. These oxides produce good range of colors. Due to this characteristic, we are able to match almost any tooth color with good esthetic results. 2. They are inert, i.e. not chemically reactive. This quality provides ceramics with good bio- compatibility. 3. Ceramic materials are translucent, like natural teeth. This translucency gives the ceramic crown a more natural appearance than any other dental material. Fig. 1.7b: Internal arrangement of tetrahedral structure of ceramic (silica) four large oxygen atoms surround smaller silicon atom Ceramics A ceramic is a compound formed by the union of a metallic and a non-metallic element (Box 1.8). Most of these materials are oxides, formed by the union of oxygen with metals such as silicon, aluminum, calcium and magnesium (Fig.1.7b). Ceramics may be simple or complex. Examples of simple ceramics are alumina and silica. Examples of complex ceramics are feldspar (potassium aluminum silicate) and kaolin (hydrated aluminum silicate). Ceramics may be crystalline or non- crystalline (i.e. amorphous). Porcelain is a specific type of ceramic used extensively in dentistry (Box 1.9). Box 1.8: Characteristics of ceramics 1. High melting points. 2. Brittleness, which means they cannot be bent or deformed (no sliding) to any extent without actually cracking and breaking. 3. They are poor conductor of heat and electricity. 4. They are chemically inert. 5. They have excellent esthetic result in terms of matching natural teeth. Fig. 1.8: Stucture of synthetic polymer Polymers They are the latest addition (early to mid- 1900s) to dental materials. Most of the polymers are nowadays synthesized by humans. Polymers are giant, long-chain organic molecules (Fig. 1.8). Polymers are characterized by covalent bonds within each molecule, giving them tremendous strength in a single direction. Try to break a nylon rope by pulling it! They are poor conductors of heat and electri- city. Most polymers have a structure containing thousands of carbon atoms linked together like beads on a string. Others, such as silicone polymers are formed with silicon-oxygen bonds. Introducton to Dental Materials Table 1.4: Characteristics of different materials 13 Characteristics Bond Properties Crystal structure Metals Metallic bonding High strength and hardness, high electrical and thermal conductivity BCC, FCC, or HCP unit cells Ceramics Ionic or covalent bonding, or both High hardness and stiffness, electrically insulating, refractory, and chemically inert Crystalline or amorphous Polymers Covalent bonding Low sensitivity, high electrical resistivity, and low thermal conductivity, strength and stiffness vary widely Amorphous and crystalline Composites Composites are combinations of any of the basic ceramic, metallic and polymeric materials (Box 1.10). Each material that makes up composites is called a phase. Their properties tend to be somewhere between those of their basic constituents and are used to enhance their performance, longevity and handling chracterstics. Box 1.10: Types of composites in dentistry 1. Ceramic - metallic composite: Tungsten carbide bur. 2. Metal - polymer composite: Die materials in dental laboratory. 3. Ceramic - polymer composite: Enamel, dentin, bone and restorative composites. A composite is a kind of "combination" of materials, which compliment each other. The properties lacking in one material are compensated by those of the other material. For example, restorative composite has two phases, namely resin and fillers. Teeth and bones are examples of natural composites. Enamel is a composite of hydroxyapatite (which is a ceramic material) and protein (which is a polymer). EVALUATION OF DENTAL MATERIALS Most manufacturers of dental materials maintain a quality assurance programme (As per international standard like ADA specifications) and materials are thoroughly tested before being released into the market for dental practitioner (Fig. 1.9). Laboratory Evaluations Most ADA/ ANSI specifications involve laboratory tests. The tests performed as per these specifications are useful but they all are performed in vitro, (carried out in the laboratory away from the clinical conditions) which have a lot of limitations in clinical practice.lO Clinical Notes 1. For example, most of the direct restorative materials are tested for their compressive strength but ultimately the material is subjected to a combination of compressive, tensile and shear stresses, which may decide the final success or failure of the material under masticatory load. 2. Similarly upper dentures mostly fracture along the midline because of bending. Hence a bending or transverse strength ~B-a-s-is-o-f-M-a-t-e-ria-I-S~c-ie-n-c-e-------------- ---------. test is far more meaningful for denture base materials than a compression test. Clinical Trials The majority of new materials are subjected to extensive clinical trials normally in co-operation with a dental college or hospital departments prior to their release. CONCLUSION As the number of available materials is going up, it is important that the dentist remains more aware about new products so that their judgement about the selection of material remains successful. Materials which have not been thoroughly evaluated should be avoided, specially with clinical dentistry falling under Consumer Protection Act (CPA). I Research and development I iI Manufacturer/analysis Ideal requirements for clinical use: Thermal, optical, mechanical, chemical, biological Available materials and their properties are evaluated Launch of new I product Choice and selection of material by the dentist Critical assessment based on clinical performance I I H feedback to IE.1.1.3.I.1 nouns denoting males and females within the family.I buchi neri, la teoria dell'informazione e la fissione nucleare sono concetti provenienti da diverse aree della fisica, ma è possibile esplorare le connessioni tra questi temi, specialmente nel contesto della fisica teorica, della meccanica quantistica e della termodinamica. Vediamo come questi argomenti si intersecano. 1. I buchi neri e la teoria dell'informazione I buchi neri sono oggetti cosmici incredibilmente densi con un campo gravitazionale talmente forte da impedire a qualsiasi cosa, anche alla luce, di sfuggire. La regione attorno a un buco nero oltrepassato l'orizzonte degli eventi è definita come quella zona da cui non è possibile tornare indietro. Secondo la relatività generale di Einstein, un oggetto che entra in un buco nero sembra "scomparire" dalla nostra visione dell'universo, sollevando uno dei più affascinanti paradossi della fisica moderna: il paradosso dell'informazione. Secondo le leggi della meccanica quantistica, l'informazione non può essere distrutta. Questo contrasta con la relatività generale, che sembra suggerire che, oltre l'orizzonte degli eventi, l'informazione sia perduta. Il dibattito sul destino di questa informazione ha portato alla formulazione del principio olografico e alla proposta della radiazione di Hawking, ideata da Stephen Hawking. Secondo Hawking, i buchi neri non sono "completamente neri", ma emettono radiazione a causa di effetti quantistici vicino all'orizzonte degli eventi, creando un potenziale "recupero" dell'informazione. Questo concetto di informazione nell'universo è cruciale anche nel contesto delle teorie termodinamiche. In particolare, la relazione tra entropia, informazione e gravità è stata esplorata in modo pionieristico dal fisico austriaco Ludwig Boltzmann, che, insieme a Rudolf Clausius, ha sviluppato la termodinamica statistica nel XIX secolo.