Daily Dental Journal Patient Article · March 2026 Edition · Clearly Explained
Which caries diagnostic methods are reliable and clinically relevant, and where do the limits of visual, tactile, and radiographic methods lie?
Clearly explained based on current scientific studies. This article helps you make informed decisions with your dentist.
This topic is about a diagnostic method and the question of how reliably it can detect certain problems.
Short and Clear
The key insights at a glance:
- The findings are mixed, with both supportive and cautionary signals.
- The scientific basis is solid, but not all questions are definitively answered.
- Bitewing radiographs detect approximal caries better than visual inspection alone.
- The best caries diagnostic method not only detects the lesion but also decides whether it needs to be treated immediately.
Why is this topic important for you?
You may have heard that there are differing opinions on this topic. This is because the science often involves more complexity than a simple yes or no answer suggests. In this article, we explain what current research actually shows — without using technical jargon and without omitting important details.
Caries detection sounds simple, but it is more diagnostic than often assumed. The question is which method provides the best decision-making basis for a given finding.
Why is this important for you? Because as a patient, understanding the background helps you make better decisions. This article does not replace your consultation with a dentist, but it gives you the knowledge to ask the right questions.
In research, key areas of focus include visual inspection vs. X-ray, early stages vs. cavitated lesions, and complementary methods such as FOTI, laser, and AI. We explain each area in detail below, what the studies say, and how this impacts your daily life.
Which is better: Visual Inspection or X-ray?
A common patient question is how to weigh visual inspection versus X-rays. The answer is not as straightforward as one might hope—but research now provides clear indications.
Visual inspection (VI) is the diagnostic baseline examination in caries detection. Kapor et al. (2021) showed that VI on occlusal surfaces in vivo has a sensitivity of 0.70 and a specificity of 0.47 at the caries detection threshold. At one-third dentin caries threshold, performance improved significantly: sensitivity 0.72 and specificity 0.77. The highest AUC of 0.89 was observed for VI at this exact threshold, indicating that visual inspection better detects advanced dentin caries than initial lesions.
Bitewing radiographs (BWR) show a complementary diagnostic strength: they detect approximal caries better than visual inspection alone. Janjic Rankovic et al. (2021) found in vitro AUC values ranging from 0.55 to 0.82 for BWR in caries detection and 0.81 to 0.92 for dentin caries detection. Digital BWR showed comparable or slightly better values. The specificity of BWR was consistently high in vitro (up to 0.97 for conventional BWR at dentin caries), indicating a low false-positive rate.
A central result of both meta-analyses is the significant variability in diagnostic performance between studies. Kapor et al. (2021) emphasized that sensitivity and specificity vary greatly depending on caries stage and examiner. The diagnostic odds ratio ranged from 1.94 to 37.77 for in vitro dentin caries threshold and from 2.14 to 60.37 for in vivo caries detection threshold. This heterogeneity limits the generalizability of individual thresholds.
Both meta-analyses identified a pronounced discrepancy between in vitro and in vivo conditions. Under laboratory conditions, the diagnostic performance of visual inspection tended to be higher than in clinical settings, while BWR and laser fluorescence sometimes showed better results than expected clinically. The authors emphasized that comparability is limited by the imbalance in study numbers and methodological differences.
Methodologically, it should be noted that included studies vary significantly in study design, follow-up period, and population selection. This heterogeneity limits the comparability of results and explains why pooled effect estimates must be interpreted with caution. Nonetheless, the direction of the effect is consistently observed across different study types.
For practical application in a German-speaking healthcare context, it is relevant that much of the scientific evidence comes from Anglo-American or Scandinavian healthcare systems. Differences in remuneration structure, treatment culture, and patient access may influence effect sizes without invalidating the underlying statement.
For practice, a synergistic diagnostic concept emerges: visual inspection is the necessary baseline examination, but it alone is not sufficient for detecting approximal and initial occlusal lesions. Bitewing radiographs complement VI systematically and are particularly superior in detecting interproximal dentin caries.
Clinicians should be aware that the diagnostic performance of all methods is stage-dependent: initial lesions are often overlooked compared to cavitated lesions. The combination of VI and BWR offers the best available diagnosis, with the indication for BWR individually based on caries risk.
In daily practice, this means that scientific evidence does not provide a unified answer but rather a framework for individualized decisions. Patient-specific factors such as general health, compliance, individual risk profiles, and treatment preferences must be considered in the decision-making process.
What does this mean for you? Bitewing radiographs detect approximal caries better than visual inspection alone.
As a patient, it's important to know: No examination method is perfect. Research shows under which conditions a method is most reliable and when you should seek a second opinion.
Science has been intensively studying this topic in recent years. For this article, more than 9 scientific works were evaluated. It's important to understand: Not every study has the same strength of evidence. Large, well-controlled studies provide more reliable results than small observational studies. The overall view of these different studies forms the picture we present here.
💡 What does this mean for you?
Bitewing radiographs detect approximal caries better than visual inspection alone. Discuss this with your dentist at your next visit what this means specifically for your situation.
What matters more: Early lesions or cavitated lesions?
When it comes to early vs. cavitated lesions, the research landscape is clearer than many think. Here's what the current studies really show.
Detecting initial, non-cavitated carious lesions is more diagnostic demanding than detecting cavitated defects. Kapor et al. (2021) showed that the sensitivity of all methods at the caries detection threshold (including initial lesions) was systematically lower than at the dentin caries threshold. For in vivo visual inspection, the sensitivity was 0.70 at the caries detection threshold, but specificity dropped to 0.47 — meaning over half of healthy surfaces were incorrectly classified as carious.
The clinical relevance of non-cavitated lesions is controversial. Not every detectable initial lesion progresses to a treatable caries. Progression depends on patient factors like fluoride exposure, saliva flow, diet, and oral hygiene. Summaries of multiple studies do not provide data on the progression rate of detected initial lesions, limiting the therapeutic consequences of purely early diagnosis.
Laser fluorescence measurements (DIAGNOdent) showed in a summary of multiple studies by Kapor et al. (2021) in vitro higher AUC values than the VE for caries detection. Clinically, the data were limited, but existing in vivo results indicated excellent diagnostic performance for conventional BWR and laser fluorescence. The authors emphasized that these results should be interpreted with caution due to the small number of studies.
Janjic Rankovic et al. (2021) confirmed a similar pattern for approximal surfaces: Sensitivity for initial lesions was lower than for dentin caries. Laser fluorescence achieved the highest AUC of 0.91 in caries detection on approximal surfaces, indicating good potential for early detection — although based on limited in vitro data.
Methodologically, it's important to note that the included studies vary significantly in study design, follow-up time period, and population selection. This heterogeneity limits the comparability of results and explains why pooled effect estimates should be interpreted with caution. Nonetheless, the direction of the effect is consistently observed across different study types.
For transferability to the German-speaking healthcare context, it's also relevant that a significant portion of scientific evidence comes from Anglo-American or Scandinavian healthcare systems. Differences in reimbursement structure, treatment culture, and patient access may affect effect sizes without invalidating the basic conclusion.
The most important clinical message is the distinction between detection and treatability. Not every diagnosed initial lesion requires restorative intervention. The decision between monitoring, non-invasive therapy (fluoride, sealants), and operative treatment requires integrating diagnostic information with individual caries risk.
Overdiagnosis carries the risk of over-treatment: Low specificity at the initial lesion threshold can lead to unnecessary invasive measures. In practice, diagnostic thresholds should be consciously chosen and adapted to clinical management.
In everyday practice, this means that scientific evidence does not provide a single answer but rather sets the framework for personalized decisions. Patient-specific factors such as overall health, compliance, individual risk profiles, and treatment preferences must be considered in making these decisions.
What does this mean for you? Initial caries is often overlooked or over-treated.
As a patient, it's important to know that no single examination method is perfect. Research shows under what conditions a method can be most reliable and when you should seek a second opinion.
How do scientists arrive at these conclusions? They don't just evaluate one study but look at many studies simultaneously. This allows them to determine whether a result is due to chance or consistently repeats itself. In this case, the findings are based on 9 scientific works from different countries and research groups.
💡 What does this mean for you?
Initial caries is often overlooked or over-treated. Discuss this with your dentist at your next visit what this means specifically for your situation.
What does "Additional Methods: FOTI, Laser, AI" mean for me as a patient?
A point that often causes confusion is additional methods: FOTI, laser, AI. However, science has made important progress in recent years.
The Laser Fluorescence Measurement (DIAGNOdent) showed good diagnostic performance in several summary reviews, sometimes exceeding the VE threshold. Kapor et al. (2021) found higher AUC values for LF than for VE in vitro, while in vivo data confirmed excellent performance. Janjic Rankovic et al. (2021) reported an AUC of 0.91 for LF in vitro approximal caries detection — the highest value among all tested methods. However, clinical comparative data were sparse.
Fiber Optic Transillumination (FOTI) was represented by only a few studies in both summary reviews. Kapor et al. (2021) identified only two FOTI studies, and no quantitative light fluorescence (QLF) studies were included. This evidence gap prevents a reliable evaluation of the clinical relevance of both methods.
AI-based caries detection on bite-wing images was examined in five studies by Ammar and Kühnisch (2024) in a summary of several studies. The pooled sensitivity was 0.87 (95% CI 0.76–0.94) with a specificity of 0.89 (95% CI 0.75–0.96), and a diagnostic odds ratio of 55.8 (95% CI 28.8–108.3). For dentinal caries, the sensitivity was 0.84 (95% CI 0.80–0.87), for smear layer caries 0.71 (95% CI 0.66–0.75). Three studies compared AI performance with dentists and found consistently higher average sensitivity of the AI models.
However, the quality of scientific evidence is limited: Of the 14 included studies, only one showed low risk of bias across all domains. Dataset sizes ranged from 112 to 3,686 bite-wing images, and 86% of the studies reported a model with at least 80% accuracy. External validation studies were largely missing, limiting generalizability.
Methodologically, it's important to note that the included studies vary significantly in study design, follow-up period, and population selection. This heterogeneity limits comparability of results and explains why pooled effect estimates must be interpreted with caution. Nonetheless, the direction of the effect is consistently observed across different study types.
For transferability to the German-speaking healthcare context, it's also relevant that a significant portion of scientific evidence comes from Anglo-American or Scandinavian healthcare systems. Differences in remuneration structure, treatment culture, and patient access may affect effect sizes without invalidating the basic conclusion.
Additional diagnostic methods can increase sensitivity but must prove their added value over the visual-radiological standard. Laser fluorescence has the strongest evidence base among additional methods, but it is not yet widely established in clinical routine.
AI-assisted caries detection is a promising field for the future, but current scientific evidence does not support recommending its routine use in clinical practice. The lack of external validation and methodological weaknesses of primary studies require further high-quality research before AI tools can be recommended as clinical decision aids.
In practice, this means that scientific evidence does not provide a single answer but rather a framework for individualized decisions. Patient-specific factors such as general health, compliance, individual risk profiles, and treatment preferences must be considered in the decision-making process.
What does this mean for you? Supplemental methods can increase sensitivity.
As a patient, it is important to know that no examination method is perfect. Research shows under which conditions a method is most reliable and when you should seek a second opinion.
What makes these results reliable? In medical research, it holds true that the more independent studies confirm the same result, the stronger the statement. The type of study and the number of participants also play a crucial role. Large controlled studies with many participants provide more reliable results than small surveys.
💡 What does this mean for you?
Supplemental methods can increase sensitivity. Discuss this with your dentist at your next visit what this means specifically for your situation.
Frequently Asked Questions
Here we answer the questions most commonly asked by patients on this topic:
❓ Is visual inspection better than X-ray?
Bitewing radiographs detect interproximal caries better than visual inspection alone.
❓ Is early-stage or cavitated lesion better?
Initial caries is often overlooked or over-treated.
❓ What does "Supplemental methods: FOTI, laser, AI" mean for me as a patient?
Supplemental methods can increase sensitivity.
❓ How reliable are the results?
The scientific basis is solid, but not all questions have been conclusively answered.
❓ Should I change my behavior based on this information?
Discuss with your dentist before making changes. This article informs you about the state of research, but every situation is individual. Your dentist knows your personal health situation best.
❓ Where can I learn more?
The detailed professional version of this article with all study details is available on Daily Dental Journal. For a personal consultation, contact your dentist.
❓ What is the main message of this article?
Caries diagnosis is method-dependent and has clinical relevance limits.
❓ Why are there different opinions on this topic?
The conflict lies between the desire for perfect early diagnosis and the reality that many initial lesions remain clinically unproblematic.
🦷 When should you see a dentist?
Schedule an appointment with your dentist if:
- You notice something unusual and want to have it checked
- You want a second opinion on a diagnosis
- You are unsure whether a recommended examination is necessary
- You have questions about the topics described in this article
- Your last dental visit was more than a year ago
Important: This article does not replace a dental visit. It helps you to be informed and engaged in the conversation.
What you can do yourself
Here are concrete steps you, as a patient, can take:
The most important in one sentence
The best caries diagnosis not only identifies the lesion but also determines whether it needs to be treated at this stage.
Note on source basis
This article is based on current scientific evidence and the DDJ editorial classification. All statements are supported by studies and presented in a patient-friendly manner.
The content has been prepared by the DDJ editorial team for patients. Medical decisions should always be made in consultation with your dentist.
Version: March 2026 · Language: American English (en-US) · Audience: Patients and interested laypeople