1. Introduction: The “Unknown” Hidden Behind Routine Procedures

When a cavity becomes deep, many people undergo “root canal treatment” (removing the dental nerve). This is an extremely common procedure, performed thousands of times daily in modern dental clinics. However, behind the absolute trust we place in this treatment lies a vast “unknown” territory that remains scientifically unmapped. 

Note: This article is based on the report “Methods of Diagnosis and Treatment in Endodontics” published by the Swedish Agency for Health Technology Assessment and Assessment of Social Services (SBU).

This comprehensive review by the SBU sent shockwaves through the dental community. It highlighted a significant “knowledge gap” in modern endodontics, revealing that many of the diagnostic and treatment methods we consider “best practices” actually lack sufficient scientific evidence. From the perspective of a science communicator, this is not merely a lack of research; it is a serious situation where the very “certainty” upon which we build daily clinical practice is being questioned.

2. Shocking Fact 1: We Cannot Accurately Diagnose “Whether a Tooth Can Be Saved”

The most fundamental issue is that we lack the means to accurately predict the fate of a damaged dental pulp (the nerve). Specifically, we lack a decisive method to determine whether a “vital but injured pulp” can be preserved or if it must be removed and replaced with artificial materials.

Currently, dentists rely on clinical signs such as pain or bleeding to make this call, but these remain within the realm of “educated guesses.” 

“We lack diagnostic methods which can disclose whether a vital but injured pulp can be maintained, or whether it should be removed and replaced with a root filling.”

No biomarkers have been identified that objectively confirm a specific pathological state. We are still forced to rely on the interpretation of clinical signs—a process inherently influenced by subjectivity. This is a formidable diagnostic barrier, distinct from treating a “dead (or infected) pulp.”

3. Shocking Fact 2: Even Latest 3D Diagnostics (CBCT) Lack a Definitive “Correct Answer”

In recent years, the spread of Cone Beam Computed Tomography (CBCT) has allowed for detailed images that were invisible on traditional 2D X-rays. However, the “construct validity”—how accurately these high-precision images reflect the actual biological condition—is not yet fully established.

Does a change on an image truly correlate with actual bacterial infection or tissue destruction? Verifying this requires meticulous research, such as analyzing biopsy tissue taken during an “apicoectomy” (endodontic surgery) and comparing it with positive or negative signs on the images. 

Furthermore, we have yet to scientifically define the true nature of the “shadows” cast by latest technology—specifically, how they link to concrete risks such as the expansion of bone destruction, root resorption, pain, or the risk of systemic disease.

4. Shocking Fact 3: Treat or Observe? The Millions of Teeth with “Asymptomatic Lesions”

Epidemiological studies estimate that in Europe alone, millions of teeth harbor apical periodontitis (bone destruction around the root) without any symptoms. These are “asymptomatic lesions” discovered by chance on X-rays.

The “inconvenient truth” here is the medico-economic aspect. Re-treating all these lesions would impose an enormous financial burden on both individual patients and society. However, there is an overwhelming lack of evidence regarding the “natural history” of these lesions—whether they will eventually cause sudden acute pain or negatively impact systemic health. We are forced to make uncertain economic decisions: should we perform expensive re-treatments out of fear, or is observation enough? We simply don’t have the answer.

5. Shocking Fact 4: Is Success Driven by “Evidence” or the “Dentist’s Skill”?

While there are many choices for disinfecting instruments and filling materials in root canal treatment, there is a surprising lack of comparative studies showing which method is clearly superior.

The issue here lies in the research design. While Randomized Controlled Trials (RCTs)—the gold standard of medicine—are ideal for measuring “Efficacy” (performance under ideal, controlled conditions), they may not fit the reality of root canal treatment, where complex factors intertwine. Instead, to understand “Effectiveness” in real-world clinical practice, we need “prospective cohort studies” that track large populations over long periods.

This is because the outcome of root canal treatment is likely influenced more by the “experience, capability, attention to detail, and skill” of the dentist than by the type of instrument used. Results achieved in an ideal environment (Efficacy), such as a university hospital or a specialist’s office, are not guaranteed to be replicated in your local dental clinic (Effectiveness). This is the greatest uncertainty in endodontics.

Conclusion: Towards New Research Centered on Patient Well-being

Historically, dental research has defined “success” based on physical measurements, such as whether a shadow on the bone has disappeared. However, the true purpose of healthcare should be to alleviate patient pain and provide satisfaction and well-being.

Moving forward, we need research from a “patient-centered” perspective—focusing not just on which technology is superior, but on how a treatment improves Quality of Life (QOL) and ensures long-term tooth survival.

I want to ask the readers: “When you are recommended a new technology or an expensive treatment, are you prepared to discuss the evidence behind it and how it contributes to your own quality of life with your dentist?”

For example, try asking:

  • “How much specifically is this treatment expected to extend the lifespan of my tooth?”
  • “If re-treatment becomes necessary, what is the success rate?”
  • “There is a shadow on the image; how does that relate to my current lack of symptoms?”

Until the day scientific progress fills these current uncertainties, we should not merely be “consumers of technology,” but “proactive decision-makers” who walk alongside our dentists for the sake of our own well-being.

Glossary Supplement

  • Endodontology: The study of the internal parts of the tooth (nerves and root canals).
  • Construct Validity: A scientific indicator of whether a test or image correctly reflects the target it is intended to measure (the actual medical condition).

Ask question/ Send the Email to Mr. Root canal, Dr. Miyashita

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