An observational study in Cracked Tooth Syndrome, sponsored by Fujian Medical University. Completed at 1 site in China. Open to participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-24.
Sponsored by Fujian Medical University · Observational
Cracked teeth are a common dental problem where tiny cracks form in the teeth. These cracks can be hard to find early, and if not treated, they may cause the tooth to break. This study aims to see if a new, non-invasive imaging method called Near-Infrared Imaging (NIRI) can help us find these cracks better in young adults aged 18 to 30 years. Participants will attend a single dental visit where they will receive a standard dental examination, including checks for pain when biting or when the tooth is tapped or exposed to cold. Additionally, pictures of their teeth will be taken using a special NIRI camera that uses a safe, painless light, and their teeth will be examined closely using a dental operating microscope, which is the current standard method for comparison. The main goals are to evaluate how accurate the NIRI method is compared to the microscope, to determine if NIRI can serve as a reliable alternative or helpful supplement for dentists, and to identify patterns and factors such as tooth position, wear, and bite that may be linked to cracked teeth, helping dentists recognize patients at higher risk. The study enrolled participants from September 2025 to March 2026 at the School and Hospital of Stomatology, Fujian Medical University.
The diagnosis of cracked teeth relies heavily on subjective clinical findings, including patient-reported pain upon biting, cold sensitivity, and visual inspection under magnification. However, these methods lack objective quantifiable measures, often leading to delayed or missed diagnoses. Near-Infrared Imaging (NIRI) has emerged as a promising non-invasive imaging modality that can detect subtle structural changes in tooth hard tissues. This study is designed to systematically evaluate the diagnostic utility of NIRI in detecting cracked teeth among young adults, using the dental operating microscope (OM) combined with clinical examination as the reference standard. This study was designed as a prospective, self-controlled, diagnostic accuracy trial. All participants underwent both diagnostic examinations: the index test was near-infrared imaging (NIRI) and the reference standard was operating microscope (OM) combined with conventional clinical examination.
62 studies on the registry are indexed under Tooth Wear; 12 are open to participants now.
This study's enrollment of 161 is above the median of 71 across 21 observational studies indexed under Tooth Wear.
Browse Tooth Wear studies →Fujian Medical University is the lead sponsor of 148 studies on the registry; 52 are open to participants now.
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This study enrolled volunteer students aged 18 to 30 years from Fujian Medical University, recruited via on-site presentations during class meetings between September 2025 and March 2026. A total of 161 participants were included in the final analysis. The study population included both males and females, with no restriction on gender. Healthy volunteers were accepted as long as they met the inclusion criteria.
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Adults aged 18 to 30 years old Presence of ≥20 natural teeth that are either unrestored or have minor restorations Willingness to provide written Capability to cooperate with clinical oral examination and NIRI scanning
Exclusion Criteria:
Presence of \<20 natural teeth History of radiotherapy or surgery in the maxillofacial region Inability to cooperate with clinical examinations or questionnaire surveys History of facial trauma Undergoing orthodontic treatment
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
This group includes young adults aged 18 to 30 years who are enrolled in this diagnostic study. All participants will undergo a comprehensive baseline oral examination, including assessment of occlusion, tooth wear, restoration status, and clinical symptoms such as biting pain, cold-stimulus pain, and percussion pain. Each participant's teeth will be examined sequentially using Near-Infrared Imaging (NIRI) and a dental operating microscope (OM), with examiners blinded to each other's results. No intervention is administered; all assessments are observational and non-invasive.
Other: Observational Assessment Only
This is an observational diagnostic study with no therapeutic intervention administered. Participants undergo a single baseline oral examination, including clinical assessment of occlusion, tooth wear, restoration status, and symptoms (biting pain, cold-stimulus pain, percussion pain), followed by two diagnostic imaging procedures: Near-Infrared Imaging (NIRI) and operating microscope (OM) examination. All procedures are non-invasive and performed for diagnostic data collection purposes only. No drug, device, or therapeutic procedure is administered as part of the study protocol.
Sensitivity and Specificity of NIRI for Detecting Cracked Teeth
Sensitivity and specificity of Near-Infrared Imaging (NIRI) for detecting cracked teeth, using dental operating microscope (OM) examination as the reference standard. Calculated at both the tooth level and the patient level with 95% confidence intervals.
Time frame: At baseline upon completion of oral examinations
Positive and Negative Predictive Values of NIRI for Detecting Cracked Teeth
Positive predictive value (PPV) and negative predictive value (NPV) of Near-Infrared Imaging (NIRI) for detecting cracked teeth, using dental operating microscope (OM) examination as the reference standard. Calculated at both the tooth level and the patient level with 95% confidence intervals.
Time frame: At baseline upon completion of oral examinations
Area Under the ROC Curve (AUC) of NIRI for Detecting Cracked Teeth
Overall discriminative ability of Near-Infrared Imaging (NIRI) assessed by the area under the receiver operating characteristic curve (AUC), with 95% confidence intervals at both the tooth and patient levels.
Time frame: At baseline upon completion of oral examinations
Diagnostic Agreement Between NIRI and Operating Microscope（OM）
Cohen's Kappa statistic evaluating the inter-method agreement between Near-Infrared Imaging (NIRI) and operating microscope (OM) examination for cracked tooth diagnosis.
Time frame: At baseline upon completion of oral examinations
Patient-Level Prevalence of Cracked Teeth
Proportion of participants classified as crack-positive by operating microscope (OM) examination, reported as a descriptive prevalence estimate in the study population.
Time frame: At baseline upon completion of oral examinations
Crack Status and NIRI Diagnostic Performance by Tooth Position
Proportion of teeth classified as crack-positive by operating microscope (OM) examination, reported separately for anterior teeth, premolars, and molars as percentages of examined teeth in each tooth position category. Subgroup analyses of the primary outcomes (sensitivity, specificity, PPV, NPV, and AUC with 95% CIs) are reported separately for each tooth position, using OM as the reference standard.
Time frame: At baseline upon completion of oral examinations
Crack Status and NIRI Diagnostic Performance by Tooth Wear
Proportion of teeth classified as crack-positive by OM examination, reported for teeth with versus without wear based on the Smith and Knight Tooth Wear Index (grades 0-4). Subgroup analyses of the primary outcomes (sensitivity, specificity, PPV, NPV, and AUC with 95% CIs) are reported by wear grade, using OM as the reference standard.
Time frame: At baseline upon completion of oral examinations
Crack Status and NIRI Diagnostic Performance by Clinical Symptoms
Proportion of teeth classified as crack-positive by OM examination, reported separately for each clinical symptom (tenderness to percussion, pain on biting, and positive cold test). Subgroup analyses of the primary outcomes (sensitivity, specificity, PPV, NPV, and AUC with 95% CIs) are reported separately for teeth with versus without each symptom, using OM as the reference standard.
Time frame: At baseline upon completion of oral examinations
Crack Status and NIRI Diagnostic Performance by Caries and Restoration Status
Proportion of teeth classified as crack-positive by OM examination, reported separately by caries status, filling status, and prosthetic restoration status. Subgroup analyses of the primary outcomes (sensitivity, specificity, PPV, NPV, and AUC with 95% CIs) are reported separately for each condition, using OM as the reference standard.
Time frame: At baseline upon completion of oral examinations
Crack Status and NIRI Diagnostic Performance by Special Dental Conditions
Proportion of teeth classified as crack-positive by OM examination, reported separately for each special dental condition (enamel hypoplasia, lateral displacement, joint clicking, central cusp deformity, and fused tooth). Subgroup analyses of the primary outcomes (sensitivity, specificity, PPV, NPV, and AUC with 95% CIs) are reported separately for each condition, using OM as the reference standard.
Time frame: At baseline upon completion of oral examinations
Patient-Level Crack Status and NIRI Diagnostic Performance by Occlusal Factors
Proportion of participants classified as crack-positive by OM examination, reported separately by occlusal factors (sex, overbite, overjet, and molar relationship). Subgroup analyses of the primary outcomes (sensitivity, specificity, PPV, NPV, and AUC with 95% CIs) are reported at the patient level, stratified by each occlusal factor, using OM as the reference standard.
Time frame: At baseline upon completion of oral examinations
Positive and Negative Percent Agreement Between NIRI and OM
Positive percent agreement and negative percent agreement between Near-Infrared Imaging (NIRI) and operating microscope (OM) for cracked tooth detection, with 95% confidence intervals.
Time frame: At baseline upon completion of oral examinations
Patient-Level Prevalence of Cracked Teeth
Proportion of participants classified as crack-positive by operating microscope (OM) examination, reported as a descriptive prevalence estimate in the study population.
Time frame: At baseline upon completion of oral examinations
Prevalence of Clinical Symptoms in Crack-Positive Teeth
Descriptive prevalence of clinical symptoms (biting pain, cold-stimulus pain, and percussion pain) among crack-positive teeth identified by operating microscope examination.
Time frame: At baseline upon completion of oral examinations
Plan to share: Yes — De-identified individual participant data, including demographic information, clinical examination results (tooth position, occlusion, tooth wear, restoration status, and clinical symptoms), and imaging data from Near-Infrared Imaging (NIRI) and operating microscope examinations will be shared.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form
Time frame: IPD and supporting information will be available starting 6 months after study completion and will remain accessible for a period of 5 years.
Access criteria: Access to IPD and supporting information will be granted upon reasonable request via email to the Principal Investigator (jia.linghui@fjmu.edu.cn). Requestors will be required to submit a brief research proposal outlining their intended use of the data. Data will be shared for non-commercial research purposes only, and a data use agreement may be required to ensure data confidentiality and appropriate acknowledgment of the original research team.
Data sharing details ↗ · www.big.ac.cn
Ran from Sep 2025 to primary completion in Mar 2026, 6 months.
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