What is Critical Thinking?

Many researchers, including Facione, Simpson and Courtneay, Banning, Brookfield, Ornstein and Hunkins, Sternberg, Ennis, and Lipman, have defined critical thinking (CT). Researchers debate whether critical thinking can be learned or if it’s a developmental process regulated by motivations, dispositions, and personality traits. Despite differences of opinion, many researchers agree that critical thinking is "Purposeful, self-regulatory judgment which results in interpretation, analysis, evaluation, and inference, as well as explanation of the evidential, conceptual, methodological, criteriological or contextual considerations upon which judgment is based ¹¹.
Critical thinking is also regarded as intellectually engaged, skillful, and responsible thinking that facilitates good judgment because it requires the application of assumptions, knowledge, competence, and the ability to challenge one’s own thinking. Critical thinking requires the use of self-correction and monitoring to judge the rationality of thinking as well as reflexivity. When using critical thinking, individuals step back and reflect on the quality of that thinking. Simpson and Courtneay point out that critical thinking processes require active argumentation, initiative, reasoning, envisioning and analyzing complex alternatives, and making contingency-related value judgments ¹².

According to Banning, critical thinking involves scrutinizing, differentiating, and appraising information as well as reflecting on information to make judgments that will inform clinical decisions ¹³. Brookfield asserts that identifying and challenging assumptions and analyzing assumptions for validity are essential to critical thinking skills. He also suggested that because critical thinkers possess curiosity and skepticism, they are more likely to be motivated to provide solutions that resolve contradictions ¹⁴.

Others such as Ornstein and Hunkins suggest that critical thinking and thinking skills refer to problem-solving and other related behaviors ¹⁵. For a number of years, dental educators thought teaching problem-solving skills was akin to teaching critical thinking skills. While teaching problem-solving skills is important to the process of learning how to use critical thinking skills, in the absence of other learning activities it may not be enough.

Sternberg, Ennis, and Lipman assert that critical thinking skills are not a fixed entity but a form of intelligence that can be taught ^16-19. The ability to develop critical thinking skills may be likened to Piaget’s concrete and formal operations. If students have not yet reached the formal operations stage, their ability to use critical thinking skills may be limited by an inability to handle abstract ideas. It is important to remember that Piaget’s stages of cognitive development are also linked to intellectual potential and environmental experiences. If the learning environment is crucial to the development of critical thinking skills, what instructional strategies can be used to promote critical thinking?
 
Sternberg asserts that critical thinking involves complex mental operations that cannot be broken into discrete styles of thinking. He claims that CT involves students’ total intellectual functioning, not a narrowly defined set of skills. He postulates that there are three mental processes fostering critical thinking: meta-components, performance components, and knowledge-acquisition strategies ²⁰. Meta-components refer to higher-order mental processes that individuals use to plan, monitor, and evaluate what they do. Performance components refer to the actual steps taken or strategies used, while knowledge-acquisition strategies refer to the ways in which individuals relate old to new material and apply new material. Sternberg does not specify a “how” approach to teaching and learning critical thinking skills. Instead, he provides general guidelines for developing or selecting a program or curriculum that will foster CTS. Interestingly, although not surprisingly, Sternberg states that students are not adequately prepared for the problems and critical thinking tasks they will face in everyday life because they are not taught these skills in their formative years ²¹. Tasks that stress right answers or truth telling or use objectively scored tests are generally removed from real-world relevance. Thus, it is particularly important that all aspects of dental educational curriculum stress real-world practice, the importance of oral health care, and the relationship of overall oral health care to systemic health by teaching students how to use critical thinking skills.

Lipman, like Sternberg, does not specify a “how to” approach. However, he makes clear distinctions between ordinary thinking and critical thinking. He explains that ordinary thinking is simplistic thinking because it does not rely upon the use of standards or criteria. Examples of ordinary thinking are guessing, believing, and supposing. Lipman describes critical thinking as a complex process based on standards of objectivity, utility, or consistency in which students can reflect upon the certainty of their thinking because critical thinking is self-correcting ²². In order words, students can defend their thinking with evidence. Ennis asserts that to help students develop critical thinking skills, teachers must understand the cognitive processes that constitute critical thinking and use instructional activities that will develop these processes. He recommends instructors teach students how to define and clarify information, ask appropriate questions to clarify or challenge statements or beliefs, judge the credibility of sources, and solve problems by predicting probable outcomes through logic or deduction. Ennis also suggests that critical thinkers demonstrate particular attributes. Critical thinkers tend to:
(1) Be capable of taking a position or changing a position as evidence dictates
(2) Remain relevant to the point
(3) Seek information as well as precision in information
(4) Be open minded
(5) Take the entire situation into account
(6) Keep the original problem in mind
(7) Search for reasons
(8) Deal with the components of a complex problem in an orderly manner
(9) Seek a clear statement of the problem
(10) Look for options
(11) Exhibit sensitivity to others’ feelings and depth of knowledge
(12) Use credible sources ²³
Critical thinkers use these skills appropriately and usually without prompting. They are generally predisposed to think critically and to evaluate the outcome of their thought processes ²⁴.
Instructional Strategies and Critical Thinking
Researchers have asserted that how educators teach has a direct influence on what is learned ²⁵. Thus, the instructional strategies selected must be appropriate to the desired outcomes. For example, strategies of inquiry are contingent upon the problem being investigated and the targeted concepts, so it is essential that they be integrated with the associated processes of inquiry in order for students to see how new knowledge evolves ²⁶. Researchers have also recommended eliminating superfluous activities and repetitious content and expanding learner-centered active forms of experiences to promote critical thinking skills ²⁷. If the goal is for students to use critical thinking skills, then the following opportunities should constitute the majority of learning activities:
a) Engaging in problem-based learning
b) Analyzing case-based scenarios
c) Engaging in debates, role-play, argument mapping, thinking aloud, and simulation among others ²⁸
The benefit of engaging students in learning experiences that utilize critical thinking skills is the public nature of their thinking. When students engage in CTS, they have an opportunity to examine tacitly held knowledge of one another, make knowledge and think explicitly, respond to questions and comments, and clarify their thinking processes ²⁹.
Several researchers stated the types of instructional strategies that may be used to promote students’ critical thinking skills. Weerts suggested that working in groups might reduce students’ stress while trying to answer difficult questions. She points out that working together may result in better answers than working alone ³⁰. Many dental educators might eschew the notion of using groups. However, it is important to acknowledge that even in classes of 80 to 100 dental students, groups of six to eight students could be developed to facilitate learning and inquiry. These groups could be responsible for answering questions about readings by being called upon randomly during class time. For example, instructors can consider writing three to four focus questions that accompany the readings to guide student comprehension. Instructors could also tell students that they should to be able to answer those questions in class. In this way, students can be held responsible for learning some of this discrete information before class. Rather than having the instructor feel responsible for “telling” students what they should know, the instructor can elicit the key concepts from students. Class time can then be used to present a case where the concept is illustrated, and students can work in groups to analyze how that concept is operationalized rather than receiving discrete knowledge through a lecture. Weerts also suggests that student groups can work together and develop critical thinking skills by:
• Identifying issues
• Gathering authoritative sources
• Identifying potential treatments
• Presenting competing points of view
• Weighing modalities in light of the presenting case and then agreeing upon the treatment plan³¹
To ensure that students are developing appropriate skills, the instructor and students can use a Likert scale to rate each other on the following criteria:
• Accuracy and relevancy of supporting evidence
• Credibility of authoritative knowledge
• Depth and breadth of thought
• Clarity and soundness of responses
Hendricson et al. suggest several active learning strategies that can be used to develop students’ critical thinking skills.

Table 2. Strategies to Enhance Critical Thinking Skills

• Use questions that require students to analyze problem etiology, compare alternative treatment modalities, provide rationales for plans of action, and predict outcomes.

• Critique cases and review decisions to identify excellent practices and to identify errors.

• Write assignments that require students to analyze problem etiology, compare alternative treatment modalities, provide rationales for plans of action, and predict outcomes.

• Analyze work products and compare how outcomes compare to best practices and compare student reasoning about problems to those of an expert panel 32

Van Gelder concurs with Hendricson et al. that critical thinking must be deliberately practiced with the intent to improve performance; however, he states that CT is hard and human beings are not naturally critical ³³. Shermer agrees and describes human beings as “pattern-seeking, story-telling animals … [who] like things to make sense, and the kinds of sense we grasp most easily are simple familiar patterns or narratives” (p. 42) ³⁴. This penchant for the familiar affects how curriculum is designed and implemented. As a type of thinking that eschews the uncritical acceptance of information, critical thinking should be a deliberate part of the curriculum. Moreover, exposing students to good examples is insufficient to developing critical thinking skills. Students must demonstrate the ability to transfer critical thinking skills from one situation to another. As Kuhn writes:
The best approach . . . may be to work from both ends at once-from a bottom-up anchoring in the regular practice [of what is being taught] so that skills are exercised, strengthened and consolidated as well as from a top-down fostering of understanding and intellectual values that play a major role in whether these skills will be used (p. 24) ³⁵.
Kuhn’s point has implications for teaching critical thinking skills in the basic science courses as well. Even though students are heavily immersed in learning a tremendous amount of information, they should still be presented with critical thinking learning experiences that embed concepts in actual practice-based scenarios ³⁶.             

Argument mapping
Van Gelder suggests that students’ critical thinking skills improve faster when instruction is based upon argument mapping. He asserts that when arguments are presented in diagrammatic form, students are more capable of following critical thinking procedures. Because argument maps are visual and more transparent, they make the core operations of critical thinking more straightforward. Van Gelder cautions, however, that belief preservation is a human tendency. He states that individuals tend to make evidence secondary to beliefs. Thus, critical thinking runs counter to human tendencies. Humans tend to seek evidence that supports beliefs and ignore evidence that goes against beliefs. Ideally, critical thinkers will recognize this, put extra effort into searching for evidence that contradicts their own beliefs and cultivate a willingness to change when evidence to the contrary begins to mount³⁷

To apply argument mapping to clinical reasoning, consider Case #1.
Case #1—Differing Views on Patient Treatment
A 60-year-old woman has internal resorption of the left maxillary lateral incisor. Radiographic exams reveal that saving the tooth is questionable. The student dentist recommends to Professor Marlin that the patient receive a fixed partial denture (FPD). Marlin confers with Professor James, and James recommends a removable partial denture (RPD).
1. The students are instructed to use argument mapping to explain the phenomenon.
2. Next, students are asked to write about the contradictions that differentiate viewpoints about FPD and RPD and to write about the counterarguments.
3. Finally, students are to identify their treatment decisions and provide evidence that supports or justifies their assertions.
Think-aloud seminar
Lee and Ryan-Wenger recommend the use of the “think-aloud seminar” as a teaching tool. Students are presented with a case and asked relevant questions regarding symptoms and presenting signs. Using this approach, students can exclude underlying pathologies based upon the presentation. This process of excluding potential diagnoses aids students’ critical thinking by encouraging them to openly verbalize the rationales behind their opinions ³⁸.
Simulation
Wong and Chung used simulation to develop diagnostic reasoning skills among nursing students. Students were asked to consider the etiological factors, presenting symptoms, and clinical signs of a patient who presented with a particular condition. As they examined the underlying patholophysiology, the CTS they developed were “assessing duration” and “frequency of symptoms and additional triggers.” They also were expected to review their understanding of the possible pathophysiological significance. The next set of CTS they focused on was “considering the pros and cons of treatments” and “drug actions and the possible side effects on the patient.” Finally they explored the efficacy of the outcomes. CTS developed in this phase were “determining the success of the treatment,” “determining complications,” “considering the time it took to resolve the clinical signs and symptoms,” and “considering reasons for the development of symptoms.”³⁹
Other strategies
Other strategies that can promote critical thinking include particular behaviors, especially asking questions.
Table 3. Strategies that Promote Critical Thinking

• Reflecting on the use of critical thinking

• Creating a climate of inquiry

• Making the teaching of thinking explicit

• Rewarding good critical thinking and challenging poor critical thinking

• Providing diverse problem contexts that are likely to engage students in critical thinking (essential) (40)

Asking particular types of questions also promotes critical thinking.  Also, Facione and Facione (1996) recommend that students begin analyzing their own thinking. For example, “If you were teaching a colleague about this situation, how would you lead him or her through the issues?” (41) Table 4. Questions that Promote Critical Thinking

• What other treatment options have you considered? Why have you chosen this approach?

• Can you give me more details?

• Can you provide some evidence that supports your recommendation?

• How could we check that?

• Is there another way to look at this problem?

Logical Fallacies
While faculty strive to develop students’ abilities to use critical thinking, it is also important to communicate the logical fallacies students may demonstrate in their writing or speaking. Engel provides an overview that illustrates the common fallacies.42 Three common types of fallacies are shown in Table 5.
Table 5. Common Logical Fallacies (Adapted from Engel, 1990)

Types of Fallacies	Examples
Fallacies of ambiguity—Argument is not sound because the words used can be understood in more than one sense • Poor sentence structure	• Using words that endow human attributes (e.g., “the organization made people…” • Using the same word to mean different things (e.g., using “man” to mean humankind and later to mean man as opposed to “woman”)
Fallacies of presumption—Argument is not sound because of unproven assumptions or overlooking, evading, or distorting facts	• Using sweeping generalizations • Premature closure (using insufficient evidence or an isolated example to make a generalization) • Begging the question (when a conclusion restates the premise using different words) • Applying either/or classifications and ignoring other alternatives
Fallacies of relevance—Argument relies on irrelevant premises or attempts to obscure issues by stirring up emotions	• Appealing to pity (rather than presenting evidence) • Appealing to ignorance (trying to prove a claim by focusing on the lack of evidence against it) • Appealing to fear • Appealing to authority (trying to persuade by citing authorities, opinion, and tradition, rather than evidence) • Ad hominem arguments (avoiding discussion of the issues by describing attributes of the people involved)

Allowing Time for Reflection Teaching students how to use critical thinking skills shifts teaching from a model that largely ignores thinking to an approach that renders it pervasive⁴³ When content is didactically taught, it is treated as static and students are unlikely to question or think it through. They tend to rely on rote memorization without grasping the logic, supporting evidence and application of what they are trying to memorize. Students who learn through a critical thinking process truly learn content. At every level, students need to learn how to:
Ask questions precisely, define contexts and purposes, pursue relevant information, analyze key concepts, derive sound inferences, generate good reasons, recognize questionable assumptions, trace important implications, and think empathetically within different points of view (p. 20) ⁴⁴.
Critical thinking is difficult and requires overt practice using a variety of learning activities across the dental curriculum. It is also important to recognize the role that reflection plays in its development. Students need time to think about what they are learning and reflect upon that information. However, what they are learning must have an impact on their feelings in order for critical thinking to occur.
Emotions and Critical Thinking
The role of emotion in learning to use critical thinking skills is yet another area that necessitates research inquiry. As Zull suggests, if we want students to retain concepts we must allow them to put things into their own words, verbally and in writing ⁴⁵. Give students time to think before speaking and better construct ideas in their own words. Processing information takes time; stating one’s thinking correctly also takes time. If a student cannot do this alone, we can give him or her the opportunity to discuss questions with others. Giving students time to reflect is giving them time to make connections.
Zull explains the process that takes place within the brain. First, the sensory cortex receives sensory input or concrete experiences. Next, the back integrative cortex tries to create meaning and images during the human process of reflection. The frontal integrative cortex is responsible for short-term memory and problem solving, making decisions and language, and making judgments and evaluations. This activity is akin to how learners handle abstractions—manipulating images and language to create new mental arrangements. The motor cortex triggers all coordinated and voluntary muscle contractions. This matches with the action that completes the learning cycle—actively testing abstractions and converting ideas into physical actions. The brain visualizes items in small amounts and all information arrives at the same time, producing an outline of objects and features in the visual field⁴⁶ Thus, the brain can fully see great detail and nuance. Converting ideas into images helps students learn. Images enhance recall and aid in discovery. Sometimes the best teaching is just showing the student how.
To ensure that students learn, educators need to limit the amount of information they give. Instructors should limit or condense to three or four pieces the amount of information they want students to process.
The amygdala is responsible for screening experiences ⁴⁷. If something is recognized as dangerous, the amygdale will instinctively cause the body to “freeze.” When a student first encounters something new, he or she may have a somewhat negative reaction. The instructor needs to find a way for the student to move into a more positive emotional territory ⁴⁸. Making suggestions or showing examples can remind the student what he or she already knows, and then the student can hang newly acquired knowledge on that “scaffolding.” The support given by the instructor allows the student some level of success. Recognizing his or her success helps the student feel more hope, interest, and curiosity. At this point, the student is able to assume more control of the learning process. Boyd (2002) concurs and states, “emotions … constantly regulate what we experience as reality.” She also points out, “The limbic system plays an important role in processing emotion and memory and therefore appears to be important in the transfer of short-term memory into long-term memory" ⁴⁹. Engaging students emotionally and actively strengthens memory.
Teaching students to use CTS during instruction

There is some empirical evidence that a four-year undergraduate experience contributes to modest gains in overall CT. However, there is little scientific evidence that a single course, other than a critical thinking skills course makes a positive measurable difference ⁵⁰. Even in the case of a specific CTS course, the evidence is mixed ⁵¹.
Recent studies show that limited efforts to infuse critical thinking in instruction can lead to improved scores on the Cornell Critical Thinking Test Level Z, a test that is aimed at a sophisticated audience and measures six common critical thinking skills ⁵². Allegrettti and Frederick (1995) reported pre- to post-test gains on the Cornell Z for a group of college seniors (n = 24) who took a capstone integrated psychology and philosophy course ⁵³. Solon (2001) found that a partial treatment group of psychology students (n = 26) improved their scores on the Cornell Z compared to a group of untreated humanities students (n = 26). The results were statistically significant (beyond .001). In 2003, Solon studied three groups to compare coursework effects and reported that the full treatment group (n = 25) significantly outscored both the partial (n = 25) and non-treatment (n = 25) groups on the Cornell Z test ⁵⁴. Solon (2007) reported that a group of introductory psychology students (n = 25) received a moderate infusion of critical thinking skills (10 hours instruction and 20 hours homework). Compared to the non-treatment group (n= 26), the experimental group significantly improved their scores on the Cornell Z test ⁵⁵. These findings suggest that even a moderate infusion of critical thinking skills instruction can result in enhanced reasoning skills without requiring a significant investment from the instructor ⁵⁶.
Collins and Onwuegbuzie reported significant relationships between overall CTS and achievement in a graduate level research methodology course at the midterm (r = .34, p < .01) and final (r = .26, p < .01) stages ⁵⁷. Onwuegbuzie compared the CTS of master’s and doctoral level students. He reported that doctoral level students (n = 19) obtained statistically higher overall CTS using the California Critical Thinking Skills Test than the masters’ degree students (n = 101, t = -3.54, p < .01). The effect size (d = 0.92) associated with this difference was extremely large ⁵⁸.

Teaching CTS requires instruction that uses higher order taxonomic skills. These skills require student demonstration or teacher usage of behaviors classified as analysis, evaluation, and creation (levels 4, 5, and 6 on Bloom’s revised taxonomy). When teaching takes place at higher levels of learning, lower order behaviors such as remembering, understanding, and applying are subsumed within instruction. The following table lists behaviors common at each level of learning and examples of related dental education activities.
Table 6.
Revised Bloom’s Taxonomy, Sample Verbs, and Related Learning Activities ⁵⁹

Taxonomic Levels from Highest to Lowest	Sample Verbs	Dental Learning Activity
Level 6—Creating	Synthesize, organize, deduce, plan, present, arrange, blend, create, devise, rearrange, rewrite	A prosthodontics patient, age 62, has two fixed mandible bridges that have deteriorated over the last two years due to poor hygiene. These bridges now need replacement. You are a recent dental graduate in practice with two senior partners. The senior partners suggest taking impressions and replacing the fixed bridges. You have read the recent literature on dental implants and would offer the patient this option. You also recognize that implants are more appropriate to the patient’s needs and that over time they represent a cost savings. However, the senior partners are not really familiar with state of the art information about implants. Develop a plan for responding to the senior partners in which you provide an evidence-based rationale for suggesting the use of dental implants.
Level 5—Evaluating	Critique, defend, interpret, judge, measure, test, select, argue, award, verify	Two patients, aged 18 months and 10 years, have cleft palate. Neither patient has been seen by health professionals or treated for this condition until now. Based on a complete summary of the dental, medical, social, and psychological health of each child, develop a treatment plan using authoritative and credible sources.
Level 4—Analyzing	Determine, discriminate, form, generalize, categorize, illustrate, select, survey, take apart, transform, classify	A 32-year-old white male arrives at your office and presents with pain and swelling over the “upper right canine tooth” for the past three days. His medical history is remarkable for GERD, for which he takes Prilosec daily, and a penicillin allergy (rash over his torso and fever after taking Keflex). Your exam reveals intraoral and extra oral swelling over tooth #6. A radiograph reveals radiolucency with caries under the crestal bone (nonrestorable). What are your concerns? How would you treat and prescribe?
Level 3—Applying	Convert, demonstrate, differentiate between, examine, experiment, prepare, produce, record, discover, discuss, explain	After completing textbook readings about the basics of periodontology, explain with images the progression of periodontal disease from the perspective of pathogenesis. Choose lay terms appropriate for use with a patient.
Level 2—Understanding	Differentiate, fill in, find, group, outline, predict, represent, trace, compare, demonstrate, describe	State four or five reasons that rubber dam isolation is essential during endodontic procedures.
Level 1—Remembering	Define, distinguish, draw, find, match, read, record, acquire, label, list	From a list of 10 options, choose the five items associated with a periodontic pocket.

Making Critical Thinking Explicit Teaching for critical thinking is a rational and intentional act. Typically, instructors cannot suddenly decide to teach CTS and develop an appropriate learning activity. An instructor must have a clear understanding of what CTS is, how it is implemented during instruction, and what strategies should be used during particular classroom and predoctoral clinical learning activities. Developing a repertoire of well-honed CTS activities appropriate to your specific discipline is advisable.
Also crucial to the teaching of CTS is an educator announcing to students he or she will teach CTS, how he or she intends to do so, and what will be required of the students as learners. It is important to have an explicit conversation with students about what CTS is, what it looks like, and how educators will model it so students can differentiate the teaching of CTS from lower level learning. Effective teaching of university-age students is characterized by collegial and collaborative processes, not instruction that is ambiguous. In ambiguous instruction, the learner does not know what to expect next or have a clear understanding of what behavioral or skill changes he or she should demonstrate as a result of teacher-student interaction. Teaching explicitly helps ensure that less re-teaching will be necessary. Both teachers and students know their responsibilities as instructors and learners.
Stages of Critical Thinking
Paul and Elder claim that individuals progress through predictable stages of unreflective, challenged, beginning, practicing, advanced, and master thinking⁶⁰. They state that unless educators help students develop an intellectual vocabulary for discussing their thought processes and challenge them to identify the problems in their thinking, the students’ cognitive processes will remain invisible to them. The implication for curriculum development: If instructors want students to develop critical thinking skills, then critical thinking must be integrated into the foundations of instruction.
It is also important to recognize that when patient care is task focused, it can obscure the bigger picture and become a barrier to the development of critical thinking skills. Individual personality, background, and position might also limit one’s ability to think critically. Additionally, gender, age, religion, and socioeconomic status might influence the development of critical thinking skills. One of the biggest barriers to the development of CTS is our educational system. Although it is important to recognize these attributes as potential barriers, it is more important that dental educators establish the kind of learning environments that will foster the development of CTS.
Case #2—Why Are Mrs. Connor’s Teeth Yellow?
Mrs. Connor, a 74-year-old white female, comes to your office as a new patient. She presents you with a complaint that her teeth have become yellowed and unattractive. Her husband died one year prior, and since then she has been drinking 8-10 cups of coffee daily. Her internist diagnosed anemia and high blood cholesterol. She is taking iron and Lipitor. She feels better since she began taking Lipitor, but feels her teeth are too yellow. She recently met a widower who invited her to dinner next week. She is worried about the appearance of her teeth.
1. Working in groups of six, students are asked to write at least four hypotheses about why Mrs. Connor’s teeth are yellow.
2. Students must also determine if whiter teeth are important to the health and well being of geriatric patients.
3. Students must discuss if there a relationship between the need of care and the use of dental services by older patients.
4. A student group will then outline its recommendations and a rationale for the treatment plan to be presented to Mrs. Connor at her next dental appointment.
Teachers must recognize that not all students will apply critical thinking skills at the same rate they learn these skills. Thus, instructional methods and objectives need to match students’ cognitive and experiential abilities while trying to stretch students to their growing edge ⁶¹. Students’ capacity for self-directed learning (SDL), which is required to implement reflective judgment, underlies many of the critical thinking skill dispositions ⁶². There is evidence that the students who routinely use the “learn by doing” approach to explore problems develop more sophisticated SDL than students in lecture-based curricula ⁶³. The reflection element of critical thinking is considered essential to clinical judgment ⁶⁴. Tanner asserts that using the skills associated with reflective thinking prepares students for ill-structured or ambiguous problems that they are likely to encounter in clinical practice ⁶⁵.
Problem-based learning (PBL) is a popular instructional strategy for promoting collaboration and reflection and negotiating different and individual constructions of knowledge. Some researchers assert that PBL is best used when problems are unsolvable or when they generate many individual constructions of knowledge that appear valid⁶⁶. However, using only problem-based learning to teach critical thinking skills may not be enough. This instructional strategy does not necessarily equip students with the ability to analyze or critique a given situation or the information with which they are been provided. A variety of instructional strategies that give students the opportunity to think aloud, role play, prioritize alternatives, communicate conclusions effectively, simulate, or defend the logical basis of their thinking is recommended to foster students’ ability to use critical thinking.

Asking students to apply their understanding of dental and medical knowledge to treatment planning and diagnosis is not an example of CTS. However, asking students to determine differential diagnoses of caries and periodontal disease among patients at various stages of lung cancer requires the ability to reason and justify particular treatment plans or demonstrate critical thinking skills. Habits of the students who demonstrate critical thinking are:
(a) Making logical inferences
(b) Offering opinions with reasons
(c) Evaluating
(d) Grasping principles
(e) Classifying
(f) Making criteria-based judgments
(g) Making evidence-based decisions
(h) Reflexivity
Case #3—Female with Erythroplakia
Mrs. Jacklin, a 40-year-old female, presents you with a history of SLE and erythroplakia on the left lateral border of the tongue. She states she is experiencing a burning sensation on her tongue. She asks why she is having this discomfort and what she can do to make the sore on her tongue go away. The oral exam shows that Mrs. Jacklin has poor oral hygiene and mild dry mouth (xerostomia) but is otherwise not in danger for oral health concerns.
1. Working in groups of four, students are asked to locate the four most recent references on oral lesions.
2. Using those resources, they are asked to write five or six reasons that the patient is experiencing a tongue lesion and determine what questions they should ask the patient about her personal and social history.
3. Next, they identify questions to ask her about her medical history.
4. Using the information they have acquired, they are asked to generate a list of potential treatment plans and the benefits and limitations of each plan.
5. What should they tell the patient and why?
Critical thinking is not:
(a) Applying what you have learned in decisionmaking and treatment planning
(b) Keeping students awake, interested, and motivated
(c) Linear or step-by-step thinking
Critical thinking cannot be taught in a learning environment where the dental educator always lectures, tells students what ought to be undertaken during patient treatment, or shows students how to do a procedure correctly. Some habits of students who do not use critical thinking skills are:
(a) Disorganization (in thought processing, preparation, and behaviors)
(b) Overly simplistic thinking (“I had enough information. There was no need to ask for additional information.”)
(c) Use of unreasonable criteria (“If my belief is sincere, evidence to the contrary is irrelevant.”)
(d) Erratic use of facts (Looking only at the area of interest, he offered biased interpretations of the radiographs.)
Critical thinking skills can be developed with frequent practice and the use of ill-structured problems and situations that require the ability to recall useful knowledge quickly, use pattern recognition, discern pertinent information, think ahead, and anticipate outcomes and problems while remaining composed so that emotions do not hinder decisionmaking skills. However, it is important to recognize CTS do not develop spontaneously or with maturation. Since strong personality components underlie CT dispositions, what happens if students admitted to colleges of dentistry do not already possess these traits?