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RESEARCH III SECOND QUARTER SUMMATIVE TEST
Quiz by Mary Ann N. Taway
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â1. Which is NOT considered a characteristic of a good statement of the problem?
A. concise
C. measurable
B. comprehensive
D. well-defined
â2. The following are considerations when writing a research rationale EXCEPT_____
A. discuss the reason for pursuing the study
B. identifies the setting or scenario that leads to pursuing a study
C. determines the gaps and challenges that motivate to continue a study
D. gives conclusions on the observable conditions and problems of community
1. Which is NOT considered a characteristic of a good statement of the problem?
2. The following are considerations when writing a research rationale EXCEPT_____
3. Why is it important to consider the variables when writing the statement of the problem?
4. Rationale is considered important part of research paper because it ________.
5. The following are factors to consider when writing statement of the problem EXCEPT_____.
6. Among the following, which factor does NOT fit to a good research problem?
7. Which of the following explains the statements below?
I. In stating the research problem, formulate an interrogative form of statements that outline and recognize the variables that may influence the result of the study
II. The rationale is the writing of the description and not the justification of the study.
8. Which of the following should NOT be included in the research rationale?
9. Which does not pertain to the background of the study to be included in research rationale?
11. TRUE or FALSE. The statement of the problem can be written with a Yes- No question granted that it is an inferential form.
12. A statement of the problem is written in what form of statement?
13. The research rationale includes the following factors EXCEPT ____________.
14. Research question pertains to the following EXCEPT _________.
15. The other term for statement of the problem is ___________.
16. Which of the following is NOT a characteristic of research question?
17. TRUE or FALSE. The ultimate goal in writing statement of the problem is to transform main problem to a specific questions.
18. TRUE or FALSE. Rationale of the study is an integral part of the Research Introduction.
19. Which of the following is NOT a focus when writing the research questions?
20. The following are considerations when writing rationale EXCEPT ________________.
21. Among the following which factor does NOT fit to a good source of research topic of a Science Investigatory Project?
22. The following are guideline in the selection of research topic EXCEPT _______.
23. Which of the following is NOT true about research topic
24. Why is it important to consider the interest of learners when choosing a research problem or topic?
25. The following are factors to consider when writing feasibility report of a research study EXCEPT___
26. Which is NOT considered when identifying the variables before writing a research title?
27. Which does not pertain to the research study that is doable and time bound?
28. Which of the following does NOT express a factor to consider for a Science Investigatory Project research proposal?
29. Feasibility report is considered important because it _______
30. Which of the following explains the statements below?
I. Your skill also pay a major part in determining what kind of study you will be working on.
II. Assess whether the proposal research title is doable and time bound
Can you make me a 40 question quiz from the following information? he story of coffee has all the elements of a bestselling novel, such as chance happenings, luck, political intrigue, the high seas and great wealth. With research, you will find many stories and dates when this happened and dates when that happened. Often these stories and dates will conflict with each other. Whatever the history, coffee has become one of the most important trading commodities in the world. Being second only to oil and being one of the most popular beverages, behind tea, beer and of course, water. Coffee growing is a very labour-intensive operation and it provides important trading income for many nations and people throughout the world. The most famous story about the origin of coffee is the story of Kaldi a goat herder from Ethiopia. It is said he noticed that his goats became very active after eating the red berries of a certain plant. He tried a few himself and noticed the stimulating effect of the berries. It is then said that monks started drinking a beverage made from the berries to help stay awake for the prayers; this would have been around 1000 AD. Over the next few hundred years the Arab world started to use the berries as a beverage and coffee was born. In those early years, coffee was mostly confined to the Muslim world with the export of coffee plants and seeds banned. But coffee could not be hidden forever so eventually coffee was introduced to Constantinople and coffee houses were opened in 1475. European traders then brought coffee back to Europe by approximately 1600. At first, coffee was met with a hostile reaction, with some Christians calling it the âDevilâs Drinkâ and asking Pope Vincent III to ban the beverage. He tried coffee and liked it so much that he is claimed to have said âThis beverage is so delicious that it would be a sin to let only misbelievers drink it! Letâs defeat Satan by blessing this beverage, which contains nothing objectionable to a Christian!â Coffee shops sprung up in every city and became an important social and networking place to meet. This tradition continues today with the French word for coffee being âCafĂŠâ. Coffee is said to have changed the social fabric of society by providing a popular non-alcoholic alternative to beer and wine. For the first time in recorded history people were not drunk all the time. Coffee today is grown and enjoyed worldwide and is one of the few crops that small farmers in third-world countries can profitably export. The coffee plant is a tree that is pruned to grow to a height of approximately three metres. This makes cultivating the beans easier as most of the beans are handpicked. The plant has white flowers similar to jasmine that grow in clusters and set to become red cherry-like fruit; beneath the red skin are two pips which are the coffee beans. Because the berries ripen at varying times the fruit must be handpicked to select only those beans ripe for harvest. This requires the picker to pick from the same plant many times and is very labour intensive. This is why coffee is grown in developing countries where labour is cheaper and foreign income is needed. Coffee plants grow best in a mountain tropical climate between the Tropic of Capricorn and the Tropic of Cancer. This mountainous land is another reason why machine picking is very difficult and hand picking is preferred. There are two main species of coffee grown today: Coffee Arabica. Coffee Robusta. Robusta grows at lower altitudes and produces a larger crop than Arabica; therefore, it is cheaper to produce Arabica is the most popular and generally considered to give superior flavour. Most Robusta is grown in Asia and Africa. About 75% of coffee grown is Arabica and 25% Robusta. Robusta is more often used as a blend with Arabica rather than a standalone coffee; used as a filler coffee in the production of instant or to add extra caffeine to an Arabica coffee for the European markets. Robusta is higher in caffeine than Arabica, but the flavour is not as palatable as the more popular Arabica bean. Coffee is produced in about 60 countries throughout the world but production is dominated by three countries producing approximately half the crop: Brazil, Vietnam and Colombia.Research IIIGRADE 9 QUARTER 2 - Research III - Quarter 1 â Module 3: Research Rationale and IntroductionEnglish III Research Guide QuizAbstract The main focus of this research is to discuss the perspective of the teamwork and its impaction organizational performance and success. Also highlight the Meanings of Team and its work sprit towards batter organizational performance and specific to its impact on the success of organization that provided the basis for this research study. In this research study a thoroughly focus was on organization and teamwork. The aim of this research is to deliver a participative view of teamwork in the organization, and also discourses the major issues and emphases on the recent work that opens the basis to move research onward. There is much worth in taking a more focus on the essential areas of teamwork. The team signifies the spirit and working capacity of the employees as team to bring organization to the success. The various explanations, definitions, processes, dimensions, team size and benefits etc. regarding the above topic teamwork and organizational success is highlighted. Keywords: Teamwork, Success, Organization, Performance, Work Groups, Employees Introduction It is indeed human beings have learned in their beginning of life to work together as (Team) that have made such a remarkable developments as unique specie. Human beings have experience throughout their social history, lived, loved, grow younger to older and worked together in groups said West M.A. (2012).The mutual social knowledge of living and functioning together creates connection among people, society and families. When work is done cooperatively as a team it can achieve extremely extra work than individually. Team can be defined as in the human society to live, to work and to play and to cooperate with others for particular task. According to John W. Newstrom et al (1993) âteam is the process of assessing performance of workers, passing information and exploring methods to increase performanceâ. If observe closely, one can discover the instances of The Government: Research Journal of Political Science Supplementary Edition Vol. III 88 The Government social (teams) they are functioning either effectively or ineffectively everywhere; organizations, schools, work place, home etc. âCoordinating the events of people is like sand house, making by using a sole particles of sandâ expressed Belbin, R. M.(2010). Moreover it is one of the general myths that the skill of team member is more important than their vigor, attention and determination for the tasks. Another widespread myth is that the team members are not alone accountable for the achievements or failures of their tasks the truth is that the members are the small parts in the teams and their individual abilities effect on the various results in team. The working relationships exist among team that might sight these relationships at different levels of involvement or relationships among the members as they move towards the degree of communication, integration and commitment increases. Terry L.G. et al (1980) expressed that âThe skills are essential if members have to work together efficiently in complex situations, only development of skills and relationships, involvement on the task regarding the particular task might be selected for reaching at target that is considered as a definition of a teamâ. Team often perform higher when they work together with sprit that enable them to achieve a collective goal at the workplace, it is not only benefits to the organization also affects the workers confidence and success. Cooperating on various tasks reduces workloads for all team members and enables them to share duties or ideas. Work as a team is the part of everyone's life, as one is a member of a family team, staff team, school team, and community teams etc., so as to understand how to work effectively as a team member. Especially there is a need when task is threatened with increasingly many problems for example; the energy problem has effects on organization, family life, and social development and the multi-dimensional nature of many problems require a scientific skill based problem solving approach. Terry L.G, et al (1980) expressed that âThe skills, competencies and efforts of team by setting priorities the team can have better impact on the problems solving such efforts can reduce work load, work duplication, and produce a result better than separate effortsâ. There are some processes of teamwork by adopting those the objectives can be achieved easily. Le Pine, et al, (2008) identified10 teamwork processes that fall in three categories following are those. TEAMWORK PROCESSES TRANSITION PROCESSES â˘Mission analysis â˘Goal specification â˘Strategy formulation ACTION PROCESSES â˘Monitoring progress toward goals â˘Systems monitoring â˘Team monitoring and backup behavior â˘Coordination INTERPERSONAL PROCESSES â˘Conflict management â˘Motivation and confidence building â˘Affect management Team Work 89 Teamwork process reduces the work stress on every member which permits members to complete given important task of organization; teamwork offers members an opening to pledge with each other. Also it develops relations between the members who start a teamwork they usually sense appreciated on productive accomplishment of task. It may be cited one of the best instances of surgical team; where surgeon is assisted by his team; nurses, anesthetist and experts etc., everyone knows that their success depends upon the teamwork. In addition they are devoted to the aim that is human life it is easy to succeed with best teamwork. The important role of manager is the team building, trust building, confidence building, in the team to achieve the task. In the Situation where all team members contribute the task, it develops the positive relationship in the team that improves the trust of team members.âFunctions effectively members of team must be flexible, committed, trusting each other and help to each otherâs in the progress and the achievement of goalsâ Expressed PlamĂnek (2008). The accountability of every member in the team must be increased so that they do not let each other down therefore they do their best for the achievements of their teams. In contrast, working alone on a task the pressure is generally high in team in those cases of small confidence impacts fewer on members. Team consists on members who always vary from each otherâs in skills, knowledge and abilities but working together that is an opportunity for them to gain skills and knowledge from each otherâs that they had never before. Working alone on a task is a challenge and using the ideas of each other brings them to come up with a mutual resolution and the achievement of the task. Nowadays theoretical development and research has rested largely a new trend that is emerging within the organizations as an essential process of teamwork. Teamwork has brought a new move in the research and development to the inputs and outputs that bound, constrain and impact on the team processes within organizations said Ilgen, D.R. (1999). The world is changes fast, any one set of instructions canât be sufficient, changes needs flexible members, teams and organizations so as to be effective on task. This paper suggests that in teams members must use the exclusive human abilities. Cannon B.et al (1995) has prĂŠcised dimensions of teams into three categories: Team dimensions 1-Cognitions: include associations, task team-mate characteristics, team mission, objectives, norms, and resources, team role interaction patterns, skills, roles, and team orientation. 2-Skills: consist on adaptability, shared situational awareness and mutual concept to conflict resolution. 90 The Government 3-Attitudes: symbolize motivation, collective potency, shared vision, team cohesion, mutual trust, collective orientation and importance of. Teamsize Researchers have given different approvals about the best size of team as Katzenbachetet al (1993) suggested that the teams should comprise on a dozen or so members which are enough to achieve a task. Although seven is the best size of the team in the organizational practices said Scharf, A. (1989). Several views of researchers are expressed in the literatures and it is difficult to decide which better is because their opinions are based on their own observations. The team size matters in the proper output and performance however from an empirical research it is also difficult to decide the suitable team size and what to accept. This study suggests that team size has a practical link with efficacy such as few or many member shave impact on the performance but size matters. Proper size of team improves the performance maximum stated Campion M. A et al (1996).These different results are expected due to the fact that appropriate team size is required for task, environment and situation where team works. However, larger teams can also experience coordination problems that delay performance. Sheppard, J. A. (1993) expressed that the question of best teamâs size is a complex one; more research is required on this topic to explain the impact of team size on given definite task. Literature Review Across many different organizations and industries teamwork is focused to increase the performance of employeesâ their unity and also create work culture. Organizations those regularly develop new ideas or products using a project-based approach and assemble teams in order to focus responsibilities to achieve the object. Researchers have given dissimilar meanings of âteamsâ. Dyer W.G. (2007) said that âteams are groups of people who trust in cooperation, if members are expert the success of goal is more possibleâ. It is essential due to the problemsolving cooperation added from many minds of team members working on a resolution of problems. Team members contribute their thoughts together to make exclusive plans for dealing with problems and this unity enhance the result due to interaction, trust and teamwork. Teamwork means a "work done by several companions with each doing a part but all subordinating personal prominence to the efficiency of the whole" Merriam, (2012). In addition combined employees are expected less hostile to each other and accepting more of each otherâs decisions. Unity of employees can increase the flow of work in organization. When employeeâs working together as a team, they learn from each other that awareness is based on their personal experiences and from coworkers; Team Work 91 employees from different departments may acquire knowledge from each other. The main object for organizations is to hold the team effort to achieve output and quality; team is a key to achieve quality productivity. According to Maddux et al (2003) âsome of the organizations have major benefits from the use of teamwork which are showed in the following chart: Benefits of Teamwork 1 Improving quality of work life for employees 2 Reducing absenteeism and increasing turnover 3 Increasing innovation and change 4 Improving organizational adaptability and flexibility A real team is mostly one where members are allowed to take decisions that how to complete task. That authority enables them to control the work process, decreases the outside control and increases the sense of duty for work. Team always feels superiority on workplace and they rely on each otherâs being there. PlamĂnek (2008) said that âaffiliation with teamwork gives member a sense of belonging, interaction and recognition of successâ. These actions support to remove the sense of loneliness of team member in organization. Effective teams can also improve efficacy through communication and trust between the team members, quality of work and decrease in absenteeism contribute to positive impact on team. Involving employees in teamwork helps the organization remain open to new ideas.âThe world of organizations is shifting individualism is out and collectivism is in, power is out, empowerment is in.â stated G. M. Parker (1998). This study discovers the experiences and difficulties of teamwork that employees and organizations are facing nowadays due to big transformation and enlarged globalization. In recent years a remarkable amendment has been emerged in the belief of team working organizations. The modern study has explored that the scope of teamwork have been appeared in system rooted in belief, and employees accept changes that denoting a modern organizational system. The organizations which are responsive to the changes appear to achieve greater satisfaction. Although it may be suggested that, the managers should assess the values and beliefs of their employees to play more dedicated role in the development of organization by making sprit to face the modern challenges. Organizational cultural is much significant and it has the excessive impact on the performance of organization and employeesâ but it is quiet arguable topic that the culture of teamwork can be developed according to the requirement. It is difficult to specify the relationships and to assess the reliable set of values to use as they believed symbol across the entire organizations. This review study focus that 92 The Government there is a great influence of organizational culture on the assumptions, values, and beliefs on the individualsâ considerations, actions and performances and so is vice versa, through learning, and training process. However the researchers believe that the organizational setup aids to unite employees of diverse cultures and dissimilar social backgrounds, traditions and have their own beliefs to work. Creating a positive teamwork culture it has several diverse aspects are goal setting, conflict resolution, empowerment, ability to accomplish tasks, measuring output and consideration for other teamwork cultures stated Pack L, et al April 27, (2012). Team work in the organization delivers employees the wisdom of unity; understand to each otherâs, and reducing conflict. In addition teamwork in organization inspires employee for impartiality by affirming that no one is ignored in the organization and all treated equally. It is known that a team in organization is bound and sincere to work with dedication to bring the success. If the employees are committed and recognize the teamwork values and its benefits, as a part of the organization they can contribute a lot to the achievement of organization. One can finds the informal instances of team at these level, family, society, community, tribe and work groups etc., and formally team appears at the level of departments, functional groups, and other organizational units. The employees feel a greater sense of achievement for being a part of an organization, if they attain team work, having freedom to work not forced. The system gives best performance to achieve recognition and credit from their managers and it will increase their effort that helps them to contribute the organizational performance. Each team batter knows about their role and how to achieve tasks. The true spirit of teamwork gives benefit to organization in maintaining its standard by which it becomes identified. The team defines its specialty, and the way it is doing task that is perceived by the organization as well as its managers and it is secured by appreciation. Employees identify what they believe; that exist in their belief system and those understandings call them to change their views to develop and raise attention towards batter performance. The literature contains sufficient definitions of teamwork and the word team is used to denote a set of generally developed as to learn collective values, attitudes and cooperation to work. The study praises that the teamwork is mostly related with the team success for instance, Wagner (1995) described that âin the team individual is less valued and group is more valued, withâ. It is found in the study that individualismcollectivism both regulates the relationships between team size, standing, and cooperation that have better effects on the cooperation of individualists rather than the cooperation of collectivists. Team Work 93 Conclusion The main concentration of this research paper is to examine more in-depth the fundamental of teamwork and its effectiveness to achieve the organizational goals. Teamwork provides vast amounts of knowledge and information, cultural differences each of these building a culture of teamwork and the skill to make the valuable solutions of the problems. To work efficiently, team members need a good understanding of how to do their job, to achieve goal and for that a basic way to ensure understanding is training, then they have to be motivated to do a job. Team is a vital activity of organization, when organization desires to perform sound it has to be confident that team functions effectively. Consequently it is compulsory to know how team performs, what manners within a team happen, and how they make decisions. If there is knowhow of teamwork events, it can be effective for the tasks that they have to accomplish. Organizations build up their own culture through tradition, history and structure these values can be accepted by team workers of an organization. The values and assumptions are the vital tools of organizations and are used as guidance for team. These have to do mostly with the basic dignity and worth of all members of team and the ability, necessity for them to solve the problems and work for the positive change. Through this review study is concluded that there is a good impact of teamwork on the organizations doings and success. Subsequently in recently developed literature there is a great focus amongst the social scientists and scholarsâ in their discussion on the above topic teamwork. The above study is also an evidence of little effort to assess the significance of teamwork in organizations success. teams in organiz1.Which Part Of The Science Investigatory Project Report Provides A Concise Summary Of The Entire Study? A) Title Page B) Abstract C) Chapter 1: Introduction And Its Background D) Chapter II: Review Of Related Literature And Studies 2.In Which Chapter Of The Science Investigatory Project Report Is The Problem Being Investigated Stated? A) Chapter 1: Introduction And Its Background B) Chapter II: Review Of Related Literature And Studies C) Chapter III: Methodology D) Chapter V: Summary, Conclusion, And Recommendation 3.Where Can You Find The Formulation Of Hypothesis In The Science Investigatory Project Report? A) Chapter 1: Introduction And Its Background B) Chapter III: Methodology C) Chapter IV: Presentation, Analysis, And Interpretation Of Data D) Chapter V: Summary, Conclusion, And Recommendation 4.Which Part Of The Science Investigatory Project Report Explains The Significance And Relevance Of The Study? A) Title Page B) Abstract C) Chapter 1: Introduction And Its Background D) Chapter V: Summary, Conclusion, And Recommendation 5.Which Chapter Of The Science Investigatory Project Report Presents The Scope And Limitations Of The Study? A) Chapter 1: Introduction And Its Background B) Chapter II: Review Of Related Literature And Studies C) Chapter III: Methodology D) Chapter V: Summary, Conclusion, And Recommendation 6.Where Can You Find The Definition Of Terms Used In The Science Investigatory Project Report? A) Title Page B) Abstract C) Chapter 1: Introduction And Its Background D) Chapter III: Methodology 7.In Which Chapter Of The Science Investigatory Project Report Are The Related Literature And Studies Discussed? A) Chapter 1: Introduction And Its Background B) Chapter II: Review Of Related Literature And Studies C) Chapter III: Methodology D) Chapter V: Summary, Conclusion, And Recommendation 8.Where Can You Find The Subject Of The Study In The Science Investigatory Project Report? A) Chapter 1: Introduction And Its Background B) Chapter II: Review Of Related Literature And Studies C) Chapter III: Methodology D) Chapter IV: Presentation, Analysis, And Interpretation Of Data 9.Which Chapter Of The Science Investigatory Project Report Presents The Research Design And Procedure Used? A) Chapter 1: Introduction And Its Background B) Chapter II: Review Of Related Literature And Studies C) Chapter III: Methodology D) Chapter IV: Presentation, Analysis, And Interpretation Of Data 10.In Which Chapter Of The Science Investigatory Project Report Are The Results And Analysis Of The Gathered Data Presented? A) Chapter 1: Introduction And Its Background B) Chapter II: Review Of Related Literature And Studies C) Chapter III: Methodology D) Chapter IV: Presentation, Analysis, And Interpretation Of DataMake 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 IResearch