Chapter 3: Listening to the Old Stories – The Literature Review

Before we can start testing our SuperPaste (our new story), we need to read every single story, article, and textbook written about toothpaste and dental caries (cavities) that came before us. This huge reading and sorting process is called the Literature Review.

1. Why We Read Old Stories (What is Known vs. Not Known)

The main reason for doing a Literature Review is to find the important link between what is known and what is not known.

• Saves Work: Imagine we need a special checklist (questionnaire) to measure how often kids brush. If we read the literature, we might find an already existing, standardized questionnaire we can use, saving us months of time!
• Know the Subject Better: Reading helps us understand why the old toothpaste failed.
• Find the Gaps (Lacunae): This is the most important part. When we finish reading everything, we look for the missing pieces (lacunae) in the knowledge. For example, maybe every study was done on teenagers, but no one has tested a new toothpaste on 6-year-olds. That is our new research topic!

2. Is it Just Reading and Summarizing? (Critical Appraisal)

No! It’s not just a simple summary. We have to be smart detectives:

• Information Seeking: First, we use special computer tools (computerized methods) to search huge online libraries called databases (like PubMed or Google Scholar). We use key words (like SuperPaste, Caries, Children) to find potentially useful articles or manuscripts.
• Critical Appraisal: This is the detective work. We don’t just read the articles; we judge them. We ask: Is this article useful for my specific question? Was the experiment done correctly? We need a scholarly appraisal—meaning we look for weaknesses (lacunae) from a research point of view, not just to find fault.

3. How We Find the Stories (The Database Search)

Finding the right dental articles in a massive database requires special search words (queries).

• The Database: Think of a database like PubMed (the biggest library of biomedical citations) as a giant digital filing cabinet. The search system uses special names for diseases and dental terms called MeSH (Medical Subject Headings).
• The Boolean Query (And, Or, Not): We connect our search words using three powerful tools:
  • AND: Used to make the search smaller and more specific. (e.g., “SuperPaste AND Children” will only show articles that mention both terms).
  • OR: Used to make the search bigger. (e.g., “Dental Caries OR Cavities” will show articles that mention either term).
  • NOT: Used to remove something we don’t want. (e.g., “SuperPaste NOT Adults” removes all articles about adults).

4. How We Organize the Stories (The Steps)

After using the Boolean Query to find all the relevant articles, we sort them:

1. Select the Studies: We read the titles and abstracts to pick the highest quality studies (e.g., we only want Randomized Controlled Trials (RCTs) if possible).
2. Scholarly Critical Appraisal: We read the full articles and note down the strengths and weaknesses. (Example: “Study X had a good design, but only tested the toothpaste for 3 months, which isn’t enough time to see the full effect on caries.”)
3. Compare Methods and Findings: We look for differences. Did Study A use a mouthwash while Study B did not? This helps us see the different approaches (methodologies).
4. Tabulate the Information: We create a table (organized chronologically, usually from recent to past) to easily compare every study side-by-side:

Study Citation	Design	Study Population	Main Finding	Lacunae/Weakness
Smith, 2024	RCT	Teenagers (15-18)	SuperPaste reduced plaque by 20%.	Only tested teenagers, not our target 6-year-olds.
Jones, 2019	Quasi-experimental	Adults	SuperPaste had no effect on recession.	Low-quality design, irrelevant population.

5. Writing the Summary (Ethical Concerns)

The final step is writing our Literature Review section.

• Introduction: Explain why we did the review (to find the lacunae).
• Empirical Literature: Write about the articles we found. We must present the content honestly and accurately. We cannot change or distort the original results.
• Conclusion/Summary: Clearly state: What is known (SuperPaste works for plaque in teens), What is not known (It’s never been tested on 6-year-olds for caries), and This is our research gap.
• Citing the Source: We must always give credit to the original authors using proper citation styles (like Vancouver style). This is an essential ethical concern—we must document our sources accurately.