Evaluation of dental caries, tooth crack, and age-related changes in tooth structure using optical coherence tomography

Assessing diagnostic accuracy and monitoring of caries progression using optical coherence tomography (OCT): A systematic review

OBJECTIVES

This systematic review analyzed studies concerning the effectiveness of Optical Coherence Tomography (OCT) in detecting and monitoring dental caries in enamel and dentin.

DATA

Studies comparing the diagnostic accuracy of OCT in diagnosing caries clinically or using extracted teeth were included.

SOURCES

Databases, including PubMed/MEDLINE, Web of Science, EMBASE, and Scopus were searched for clinical trials and studies conducted using human teeth between 2010 and 2024. The process of study selection and data extraction followed the PRISMA guidelines. The methodological quality of the included studies was evaluated using the Critical Appraisal Skills Programme (CASP) diagnostic study checklist.

STUDY SELECTION

Seven studies met the inclusion criteria out of 1,266 articles identified. OCT modalities used in these studies include Cross-polarization OCT (CP-OCT), Swept-source OCT (SS-OCT), and polarization-sensitive (PS-OCT), with wavelengths ranging between 1310 and 1330 nm; axial resolutions were between 7.5-22 μm. SS-OCT had a high sensitivity of 74.1 % and specificity of 95.7 % when applied to caries detection. CP-OCT was able to identify dentin-penetrating lesions with greater accuracy than conventional radiography. There were strong correlations in the OCT measurements with the established diagnostic gold standards: polarized light microscopy (PLM), r = 0.63, P < 0.01; transverse microradiography (TMR), r = 0.75, P < 0.001.

CONCLUSION

OCT has demonstrated better performance regarding early caries detection and its activity compared with traditional diagnostic methods. However, standardization of the imaging protocol and further larger clinical trials are required.

CLINICAL SIGNIFICANCE

OCT offers significant clinical advantages in the diagnosis of dental caries. This technology enables early detection of carious lesions, facilitating timely intervention and potentially preserving tooth integrity. Investigating the clinical effectiveness of OCT is crucial to validate its utility in dental practice and to establish standardized protocols for its implementation in caries diagnosis.

Expert consensus on the prevention and treatment of enamel demineralization in orthodontic treatment

Enamel demineralization, the formation of white spot lesions, is a common issue in clinical orthodontic treatment. The appearance of white spot lesions not only affects the texture and health of dental hard tissues but also impacts the health and aesthetics of teeth after orthodontic treatment. The prevention, diagnosis, and treatment of white spot lesions that occur throughout the orthodontic treatment process involve multiple dental specialties. This expert consensus will focus on providing guiding opinions on the management and prevention of white spot lesions during orthodontic treatment, advocating for proactive prevention, early detection, timely treatment, scientific follow-up, and multidisciplinary management of white spot lesions throughout the orthodontic process, thereby maintaining the dental health of patients during orthodontic treatment.

Marginal adaptation analysis of CAD/CAM resin crown with non-invasive methods

OBJECTIVES

This study compared the silicone replica method with swept-source optical coherence tomography (SS-OCT) to analyze marginal adaptation and investigated the effect of the light incidence angle of SS-OCT on measurement precision.

MATERIALS AND METHODS

A typodont-prepared mandibular right first molar was scanned using an intraoral scanner (Trios 3). Fourteen crowns were fabricated from CAD/CAM resin blocks (Katana Avencia P) using a 5-axis milling machine (DWX-50). Marginal adaptation at the buccal, lingual, mesial, and distal points was assessed using the silicone replica method and SS-OCT at light incidence angles of 60°, 75°, and 90°. Statistical comparisons were performed using two-way analysis of variance (ANOVA) and t-tests with Bonferroni correction, and t-tests at a significance level of 0.05.

RESULTS

At 60°, SS-OCT showed significantly larger marginal discrepancies than the silicone replica method at the buccal, lingual, and mesial points (p < 0.05). At 75°, only the lingual point showed a significantly larger value than the silicone replica method (p < 0.05). At 90°, no significant differences were observed between the SS-OCT and silicone replica methods (p > 0.05). Marginal discrepancy values increased as the angle changed from 90° to 75° to 60°, with significant differences between 60° and 75° and between 60° and 90° at the buccal and lingual points (p < 0.05).

CONCLUSIONS

SS-OCT is a viable alternative to the silicone replica method for assessing marginal adaptation at an incidence angle of 90 °.

CLINICAL RELEVANCE

SS-OCT, a non-invasive method, has the potential to be applied clinically for evaluating marginal fit in indirect restorations in vivo.

Effects of mixing of europium oxide in resin composites on the fluorescence characteristics and mechanical properties

OBJECTIVE

The objective of this study is to disperse europium oxide (Eu2O3) in a resin composite (RC) using a planetary centrifugal mixer and assess its effects on photoluminescence and mechanical properties.

MATERIALS AND METHODS

A commercially available RC was mixed with Eu2O3 at various concentrations using a planetary centrifugal mixer. The fabricated samples were evaluated using scanning electron microscopy and a spectrofluorometer to assess their crystal structures, particle sizes, and photoluminescence properties. Vickers microhardness measurements were performed, along with a three-point bending test. Statistical analyses were performed to assess the mechanical properties.

RESULTS

The intensity of red fluorescence increased with the increase of europium oxide concentration. The fluorescence spectra at 613 and 620 nm exhibited higher intensities under excitation at 254 nm. Eu2O3 was dispersed in RC regardless of the Eu2O3 concentration, and no aggregation was observed. Regarding the mechanical properties, there were no significant differences in the flexural strength or modulus, and the Vickers hardness gradually increased with increasing Eu2O3 concentration.

CONCLUSION

To mix Eu2O3 with RC, visible fluorescence emission was observed even with increasing the Eu2O3 concentration, and the mechanical properties of RC were unaffected. Based on our study, a 15 wt% concentration of Eu₂O₃ is the appropriate concentration, as it achieves strong fluorescence emission without compromising the mechanical properties or color tone of the RC.

Resin infiltration of trauma-induced enamel cracks - a proof-of-concept

OBJECTIVES

The aim of this in-vitro study was to investigate the masking efficacy of adhesively sealed enamel cracks with resin infiltration compared with the use of a universal adhesive.

METHODS

Enamel cracks were induced on the labial surfaces of bovine teeth using a pendulum impact tester. Specimens were treated adhesively by resin infiltration with ICON (DMG) or Scotchbond Universal Plus (3M). Standardized digital images were taken pre- and postoperatively by three methods: flashlight from the front, transmitted light from behind, and DiagnoCam (KaVo). Four calibrated raters performed the qualitative visual evaluation of all images of each type: severely visible enamel cracks (1), clearly visible enamel cracks (2), slightly visible/aesthetically acceptable enamel cracks (3) and no visible enamel cracks (4). Specimens were selected to measure infiltration depth by confocal microscopy.

RESULTS

Postoperatively, the masking efficacy in teeth with enamel cracks was significantly higher using ICON compared with Scotchbond Universal Plus in all groups (p < 0.001). Infiltration depths of ICON were significantly higher compared to those of Scotchbond Universal Plus (p < 0.002).

CONCLUSIONS

Resin infiltration offers a straightforward and effective treatment option for masking trauma-induced enamel cracks, demonstrating superior efficacy over adhesive sealing. Further studies are necessary to evaluate the long-term stability of the optical improvements achieved through resin infiltration.

CLINICAL SIGNIFICANCE

Resin infiltration might pose a therapeutic option for clinicians to enhance the aesthetic appearance of trauma-induced enamel cracks.

Three-Dimensional Assessment of Dental Enamel Microcrack Progression After Orthodontic Bracket Debonding Using Optical Coherence Tomography

The current study aimed to quantify the length progression of enamel microcracks (EMCs) after debonding metal and ceramic brackets, implementing OCT as a diagnostic tool. The secondary objectives included a three-dimensional assessment of EMC width and depth and the formation of new EMCs. OCT imaging was performed on 16 extracted human premolars before bonding and after debonding. Debonding was conducted with a universal Instron machine, with ARI values recorded. Additionally, 2D and 3D OCT images were employed to detect EMC formation and progression. Enface images quantified the length, width, and number of EMCs, and the length and width were analyzed using Image J (1.54f) and MATLAB (R2014b), respectively. Sagittal cross-sectional images were used for EMC depth analysis. A paired t-test showed significant differences in the length, width, and number of EMCs after debonding (p-value < 0.05), while the Wilcoxon non-parametric test indicated significant EMC depth changes (p-value < 0.05). No significant results were identified for the EMC number in ceramic brackets and EMC depth in metal brackets. Three-dimensional OCT imaging monitored existing EMCs at higher risk of progression and detected new EMCs following orthodontic bracket debonding. This study provides novel insights into EMC progression regarding the length, width, depth, and number after debonding.

Multi-channel delay sampling to extend imaging depth in high-speed swept-source OCT systems

We present a multi-channel delay sampling method to extend imaging depth in high-speed swept-source optical coherence tomography (SS-OCT). A balanced detector captures interference signals, converting them into electrical signals, which are then split into N channels, each with fixed time delays determined by the length of electrical cables. Then, they are digitized by an N-channel acquisition card. A calibration procedure is utilized to compensate for non-uniform phase shifts resulting from fixed time delays. The N-channel signals are merged in k-space and resampled to obtain a linearized spectrum, which increases the sampling rate by a factor of N, thereby extending the ranging distance by N times, all without altering k-clock triggering or sacrificing other imaging performance. The signal-to-noise ratio and sensitivity within the original depth range also have been enhanced. This advancement contributes to the improvement of the overall performance of SS-OCT systems.

Optical clearing agents based on metallic and dielectric nanoparticles for caries diagnostic by optical coherence tomography

OBJECTIVE

This study aimed to assess the effect of titanium dioxide (TiO2) and silver (Ag) nanoparticles dispersed in glycerol or water, serving as optical clearing agents nanocolloids (OCAs-NC), for improving optical coherence tomography (OCT) images and highlighting incipient lesions in ex vivo human teeth.

MATERIALS AND METHODS

Twelve human teeth with incipient lesions were divided into seven groups according to the OCA-NC; they were subjected to G1 (air), G2 (glycerol), G3 (TiO2 0.1%), G4 (TiO2 0.01%), G5 (TiO2 0.001%), G6 (AgNO3 10%), and G7 (AgNO3 100%). The OCA-NC was applied to the occlusal surface, and two-dimensional images of the specimens were analyzed using OCT (930 nm central wavelength; 100 nm bandwidth; 5 mW output power; axial resolution of 7/5.3 μm in water and air, respectively; lateral resolution of 8 μm; and light penetration depth of 1.6 mm inside the sample).

RESULTS

The findings demonstrated that the utilization of OCAs-NC containing metallic or dielectric nanoparticles (AgNO3 and TiO2) led to improved differentiation between sound and demineralized enamel on occlusal surfaces. Additionally, it enhanced the depth of image penetration when analyzing this hard tissue with OCT.

CLINICAL RELEVANCE

In the current context of minimally invasive dentistry, the use of OCAs-NC in conjunction with OCT can provide clinicians with early diagnosis, allowing for the determination of less/more invasive therapies and consequently halting the disease before cavitation of dental tissues occurs.

A Drosophila heart optical coherence microscopy dataset for automatic video segmentation

The heart of the fruit fly, Drosophila melanogaster, is a particularly suitable model for cardiac studies. Optical coherence microscopy (OCM) captures in vivo cross-sectional videos of the beating Drosophila heart for cardiac function quantification. To analyze those large-size multi-frame OCM recordings, human labelling has been employed, leading to low efficiency and poor reproducibility. Here, we introduce a robust and accurate automated Drosophila heart segmentation algorithm, called FlyNet 2.0+, which utilizes a long short-term memory (LSTM) convolutional neural network to leverage time series information in the videos, ensuring consistent, high-quality segmentation. We present a dataset of 213 Drosophila heart videos, equivalent to 604,000 cross-sectional images, containing all developmental stages and a wide range of beating patterns, including faster and slower than normal beating, arrhythmic beating, and periods of heart stop to capture these heart dynamics. Each video contains a corresponding ground truth mask. We expect this unique large dataset of the beating Drosophila heart in vivo will enable new deep learning approaches to efficiently characterize heart function to advance cardiac research.

Use of Digital Diagnostic Aids for Initial Caries Detection: A Review

The advance in digital diagnostic technologies has significantly facilitated the detection of dental caries. Despite the increase in clinically available digital diagnostic aids for dental caries, there is yet to be a comprehensive summary of all available technology. This review aims to provide an overview of digital diagnostic aids for the clinical detection of dental caries, particularly those at an initial stage. Currently available digital diagnostic aids for caries detection can be classified into four categories according to the initial source of energy, including radiation-based aids, light-based aids, ultrasound-based aids, and electric-based aids. Radiation-based aids use ionizing radiation, normally X-ray, to produce images of dental structures. Radiation-based aids encompass digital bitewing radiography and cone beam computed tomography. Light-based aids employ light or laser to induce signals for the detection of the changes in the carious dental hard tissue. Common light-based aids include digital transillumination and light/laser-induced fluorescence. Ultrasound-based aids detect the signal of ultrasound waves to assess the acoustic impedance of the carious teeth. The ultrasound caries detector is an available ultrasound-based aid. Electric-based aids assess the changes in the electric current conductance or impedance of the teeth with caries. Available electric-based aids include electrical conductance measurement and alternating current impedance spectroscopy. Except for these clinically available digital diagnostic aids, many digital diagnostic aids for caries detection are still under development with promising results in laboratory settings.

Quantitative analysis of the degree of demineralization for bleached enamel by optical coherence tomography

BACKGROUND

Tooth bleaching imparts whitening effects along with adverse effects such as increased tooth sensitivity and enamel surface changes. Herein, we employed optical coherence tomography (OCT), a nondestructive optical detection technique, for evaluation of tooth enamel after treatment with peroxide-based bleaching agents.

METHODS

Fifteen enamel samples were bleached using 38% acidic hydrogen peroxide-based bleach, subjected to OCT scanning, and then cross-sectioned and imaged under polarized light microscopy (PLM) and transverse microradiography (TMR). OCT cross-sectional images were compared with PLM and TMR. The depth and severity of demineralization produced in the bleached enamel were measured by OCT, PLM, and TMR. Comparison between the three techniques was performed using Kruskal-Wallis H non-parametric test and Pearson correlation.

RESULTS

In comparison with PLM and TMR, OCT clearly detected the changes in the enamel surface after hydrogen peroxide bleaching. Significant correlations (p<0.05) were observed in lesion depth between OCT and PLM (r=0.820), OCT and TMR (r=0.822), and TMR and PLM (r=0.861). There was no statistically significant difference in demineralization depth values measured by OCT, PLM, and TMR (p>0.05).

CONCLUSION

OCT can allow real-time, non-invasive imaging of artificially bleached tooth models and automatically measure the early changes in the enamel lesion structure upon exposure to hydrogen peroxide-based bleaching agents.

Noninvasive diagnostic method using optical coherence tomography detected a vulnerable dentin enamel junction created by phosphoric acid etching

To investigate the influence of phosphoric acid etching on the dentin enamel junction (DEJ) using optical coherence tomography (OCT). Human teeth were assigned to four groups: 1. control, no additional treatment (CT); 2. The primer of "SE Bond2" was applied (SE), 3. "Enamel Conditioner" was applied (EC), 4. "K-etchant syringe" was applied (KE). After treatment, the DEJ was observed using a laser microscope (CLSM), OCT, and scanning electron microscopy (SEM). Additionally, an ultimate tensile strength (UTS) test at the DEJ was performed. No cracks were observed by CLSM. In contrast, cracks were observed all samples by SEM. Additionally, OCT revealed a white line along the DEJ in all KE specimens and some EC specimens. The UTS test showed a significant difference between CT and KE. This study found that phosphoric acid etching may cause excessive demineralization and weaken the DEJ. This fragility was observed using a non-invasive diagnostic method using OCT.

A pilot study comparing optical coherence tomography, radiography, clinical photography, and polarisation microscopy for studies of hypomineralisation disturbances in enamel

Aim

To investigate the use of optical coherence tomography (OCT) as a tool to assess general and localised hypomineralisation defects in the enamel.

Design and Materials

Ten extracted permanent teeth (four teeth with localised hypomineralisation, four teeth with general hypomineralisation, and two healthy controls) were used in this study. In addition, four participants who underwent OCT served as living controls for the extracted teeth.

Methods

The OCT results were compared with clinical photographs, digital radiographs, and polarising microscopy images of tooth sections (considered the gold standard) to determine the method with the most accurate information regarding the extent of enamel disturbances: 1) visibility of enamel disturbance (visible yes/no); if yes, 2) extent of the disturbance in the enamel; and 3) determination of the plausible involvement of the underlying dentin.

Results

OCT was more accurate than digital radiography and visual assessment. OCT could provide information about the extent of localised hypomineralised disturbances in the enamel that was comparable to that with polarisation microscopy of the tooth sections.

Conclusion

Within the limitations of this pilot study, it can be concluded that OCT is suitable for investigating and evaluating localised hypomineralisation disturbances; however, it is less useful in cases with generalised hypomineralisation of the enamel. In addition, OCT complements radiographic examination of enamel; however, more studies are necessary to elucidate the full extent of the use of OCT in case of hypomineralisation.

Effect of cigarettes smoke on bonded polymeric restorations: OCT study

Background

Up to date, the effect of cigarette smoke (CS) on the adhesive properties of the restorative materials bonded to tooth structure is still unclear. It is still questionable if it interferes with the durability and clinical success of these restorations. Few numbers of studies reported the assessment of microgaps of dental composite using cross-polarization optical coherence tomography (CP-OCT). The aim of this study was to evaluate the presence of interfacial microgaps between composite resin restoration and the tooth structure with or without exposure to CS under the CP-OCT.

Materials and methods

In this in-vitro study, a standardized round class-V cavities were prepared in twenty extracted, caries-free human molar teeth, and they were divided randomly into two groups (n = 10). Adhesive system (Gluma universal, Kulzer GmbH) was applied followed by filing the prepared cavities with flowable composite restoration (Charisma, Kulzer GmbH). Then, exposure to CS (40 cigarettes/day) was carried out for 14 days and the samples were stored in normal saline solution after each smoke exposure cycle. Next, all samples were immersed in ammoniac silver nitrate for 24 h, followed by immersion in a photo-developing solution for 8 h. Optical comparison was carried out by CP-OCT to assess microgaps percentage between smoke (SG) and non-smoke groups (NSG) at the axial walls (AW) and cavity floor (CF).

Results

Independent T-test showed that there was a significant difference between the two groups (SG, NSG) in AW microgaps percentage (p = 0.008), while there was no difference in CF (p = 0.15).

Conclusion

It can be inferred from the current finding that OCT can be used to predict the adaptability of the bonded restoration under the thermochemical influence. CS has a negative effect on the marginal integrity of the bonded polymeric restorations.

Treatment of cracked teeth: A comprehensive narrative review

OBJECTIVES

The term "cracked tooth" is used to describe an incomplete fracture initiated from the crown and progressing towards a subgingival direction. Despite the high prevalence of cracked teeth and their frequent association with symptoms and pulpal or periapical pathoses, there is still no consensus in the literature with regard to their restorative and endodontic management. Therefore, the aim of this narrative review was to evaluate the most relevant research and provide an up-to-date comprehensive overview regarding the treatment of cracked teeth.

MATERIALS AND METHODS

An electronic literature search was carried out in MEDLINE (via Ovid), Embase (via Ovid), Scopus, and Web of Science as well as several "Grey literature" sources up to February 22nd 2022 using a combination of pre-specified 'free-text' terms (keywords) and "subject headings." The search process was supplemented by handsearching in relevant dental journals and reference lists. This narrative review focused on clinical follow-up studies (observational or interventional studies, case series/reports), laboratory studies and systematic reviews written in English language that reported data on treatment of permanent cracked teeth. The selection of relevant studies was carried out by two reviewers (AK and DG) working independently in two consecutive stages: title/abstract screening and full-text retrieval. Any discrepancies in the study selection were resolved by discussion between the reviewers.

RESULTS

In total, 64 articles were selected for inclusion in this narrative review.

CONCLUSIONS

Cracked teeth with normal pulp or reversible pulpitis have exhibited high pulp and tooth survival rates by the provision of direct or indirect composite restorations. Besides, recent data favour monitoring, especially in the absence of symptoms or compromised tooth structure. When endodontic intervention is required, current evidence suggests that along with appropriate restorative management, outcomes of cracked teeth may be comparable to those of non-cracked root filled teeth.

Numerical Modeling of a New Type of Prosthetic Restoration for Non-Carious Cervical Lesions

The paper considers a new technology for the treatment of non-carious cervical lesions (NCCLs). The three parameterized numerical models of teeth are constructed: without defect, with a V-shaped defect, and after treatment. A new treatment for NCCL has been proposed. Tooth tissues near the NCCLs are subject to degradation. The main idea of the technology is to increase the cavity for the restoration of NCCLs with removal of the affected tissues. The new treatment method also allows the creation of a playground for attaching the gingival margin. The impact of three biomaterials as restorations is studied: CEREC Blocs; Herculite XRV; and Charisma. The models are deformed by a vertical load from the antagonist tooth from 100 to 1000 N. The tooth-inlay system is considered, taking into account the contact interaction. Qualitative patterns of tooth deformation before and after restoration were established for three variants of the inlay material.

Tooth Wear and Tribological Investigations in Dentistry

Dental or tooth wear is a physiological process in the life cycle of teeth. Loss of the occlusal surface may cause excessive tooth wear. Several factors may contribute to tooth wear with different intensities and duration in the oral cavity. The oral cavity is generally compared to a tribological system to determine the various types of wear between teeth and restorative materials and assess the amount of dental wear. However, it is challenging to investigate in vitro and in vivo wear owing to the complexity of tooth wear; thus, a clear correlation between in vitro and in vivo data could not be established. This review is aimed at providing an insight into the etiology of tooth wear and tribological investigations in dentistry.

Intraoral optical coherence tomography and angiography combined with autofluorescence for dental assessment

There remains a clinical need for an accurate and non-invasive imaging tool for intraoral evaluation of dental conditions. Optical coherence tomography (OCT) is a potential candidate to meet this need, but the design of current OCT systems limits their utility in the intraoral examinations. The inclusion of light-induced autofluorescence (LIAF) can expedite the image collection process and provides a large field of view for viewing the condition of oral tissues. This study describes a novel LIAF-OCT system equipped with a handheld probe designed for intraoral examination of microstructural (via OCT) and microvascular information (via OCT angiography, OCTA). The handheld probe is optimized for use in clinical studies, maintaining the ability to detect and image changes in the condition of oral tissue (e.g., hard tissue damage, presence of dental restorations, plaque, and tooth stains). The real-time LIAF provides guidance for OCT imaging to achieve a field of view of approximately 6.9 mm × 7.8 mm, and a penetration depth of 1.5 mm to 3 mm depending on the scattering property of the target oral tissue. We demonstrate that the proposed system is successful in capturing reliable depth-resolved images from occlusal and palatal surfaces and offers added design features that can enhance its usability in clinical settings.

Modifications of the Dental Hard Tissues in the Cervical Area of Occlusally Overloaded Teeth Identified Using Optical Coherence Tomography

Background and objectives: Occlusal overloads produce a series of manifestations in teeth, especially attrition and non-carious cervical lesions (NCCL). Optical Coherence Tomography (OCT) can highlight and evaluate tooth lesions. The aim of this study was to examine the changes of dental hard tissues in the cervical area because of occlusal overload by macroscopic examination and using in vitro Swept Source OCT examination. Materials and Methods: The study was performed on 21 extracted teeth with occlusal trauma. After macroscopic and OCT examination, the 2D OCT images were transformed into 3D images using ImageJ software. Statistical analysis of macroscopic and OCT images was performed with Statistical Package for Social Sciences. Results: On 21 teeth, 88 cervical lesions (cracks) were identified. Upper premolars with an occlusal Smith and Knight tooth wear score of 2 had the most NCCL. Statistical analysis revealed significant differences in the median widths of cervical lesions between teeth with score 1 and score 3. Additionally, we obtained statistically significant differences in median widths between the buccal and oral surfaces. Conclusions: These cracks can be considered precursors of NCCL. NCCL can be located on dental surfaces in the cervical area other than the buccal one. A 3D reconstruction of OCT images emphasized that cracks are located especially at enamel level, evolving towards the enamel-dentin junction, with multiple ramifications.

Oral Cancer Screening by Artificial Intelligence-Oriented Interpretation of Optical Coherence Tomography Images

Early diagnosis of oral cancer is critical to improve the survival rate of patients. The current strategies for screening of patients for oral premalignant and malignant lesions unfortunately miss a significant number of involved patients. Optical coherence tomography (OCT) is an optical imaging modality that has been widely investigated in the field of oncology for identification of cancerous entities. Since the interpretation of OCT images requires professional training and OCT images contain information that cannot be inferred visually, artificial intelligence (AI) with trained algorithms has the ability to quantify visually undetectable variations, thus overcoming the barriers that have postponed the involvement of OCT in the process of screening of oral neoplastic lesions. This literature review aimed to highlight the features of precancerous and cancerous oral lesions on OCT images and specify how AI can assist in screening and diagnosis of such pathologies.

Applications of Optical Coherence Tomography in the Diagnosis of Enamel Defects

Developmental defects of enamel (DDEs) are deviations from the normal appearance in terms of the quantity and quality of tooth enamel. They may be genetic or acquired. The most important DDEs are hypomineralization and hypoplasia. The aim of this study was to produce “in vivo” DDE in Wistar rats by administering amoxicillin to pregnant females and to highlight these lesions after sacrifice of the pups by macroscopic and microscopic examination and optical coherence tomography (OCT). Amoxicillin (100 mg/kg) was administered to two pregnant Wistar female rats for the production of DDEs. When the pups were 2 months old, they were sacrificed, and their jaws were harvested together with their teeth. The jaws were examined macroscopically, microscopically, and by OCT. Following the macroscopic and microscopic examination, it was established that four pups had a total of 42 DDE lesions. At the OCT examination, the hypomineralization was characterized by an intense, inhomogeneous OCT signal, and the hypoplasia was characterized by the absence of the signal. Administration of amoxicillin to pregnant females of Wistar rats resulted in DDEs in their offspring. The OCT examination confirmed the presence of these lesions in the teeth of rat pups.

Review of Cracked Tooth Syndrome: Etiology, Diagnosis, Management, and Prevention

Cracked tooth syndrome refers to a series of symptoms caused by cracked teeth. This article reviews the current literature on cracked tooth syndrome from four aspects, etiology, diagnosis, management, and prevention, to provide readers integrated information about this. The article begins with an introduction to the odontiatrogenic factors and then covers the noniatrogenic factors that induce cracked tooth syndrome. While the former discusses inappropriate root canal therapy and improper restorative procedures, the latter covers the topics such as the developmental and functional status of cracked tooth syndrome. This is then followed by the description of common clinical diagnosis methods, the prospects of new technologies, and summaries of current clinical management methods, including immediate management and direct and indirect restoration. In the final section, preventive methods and their importance are proposed, with the aim of educating the common population.

Present status and future directions: Endodontic management of traumatic injuries to permanent teeth

The prognosis of traumatized teeth depends largely on the fate of the pulp and its treatment. This review aims to update the present status on the endodontic management of traumatic injuries to permanent teeth and to identify relevant research areas that could contribute to an improvement in diagnosis and treatment of traumatized permanent teeth. Future research should pay greater attention to (1) diagnostic methods to assess the perfusion of the pulp and enhance detection of tooth cracks and initial signs of root resorption; (2) improved materials for vital pulp treatment; (3) studies focusing on type and duration of splinting after root fractures; (4) antiresorptive intracanal medication in case of posttraumatic pulp necrosis and infection-related resorption and (5) long-term data on the apical barrier technique compared to revitalization.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2020 professional literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to this work to cover this broad topic. Specific subject areas addressed include prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders (TMDs); sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence day-to-day dental treatment decisions with a keen eye on future trends in the profession. With the tremendous volume of dentistry and related literature being published today, this review cannot possibly be comprehensive. The purpose is to update interested readers and provide important resource material for those interested in pursuing greater detail. It remains our intent to assist colleagues in navigating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the dental patients they encounter.

Advanced imaging of dentin microstructure

This study aimed to demonstrate the feasibility of using optical coherence tomography (OCT) for locating the sectioning site of a specimen before characterizing the ultrastructural features of dentin surfaces as well as the inner wall of the dentinal tubules (DT) using a field emission scanning electron microscope (FESEM). Eight sound human molar teeth were extracted, examined via cross-polarization optical coherence tomography (CP-OCT), embedded, and hemisectioned using a low-speed diamond sawing machine. Next, each sectioned surface was further trimmed, polished, and examined under a confocal laser scanning microscope (CLSM) to locate the target area on the superficial dentin. Subsequently, each section was gold-coated and examined using FESEM. Backscattered reflection from the dentin layer was less than that from the enamel under CP-OCT. Distinct reflections from certain enamel and dentin microstructures were observed before sectioning the specimens. Areas with enamel cracks and dentin defects were identified and avoided during sectioning. At the micron level, the CLSM images exhibited a homogenous distribution of the DT orifices. Low magnification FESEM images showed intertubular dentin as a loosely condensed globular layer with shallow grooves in between, whereas peritubular dentin exhibited more organized condensation of apatite crystals surrounding the DT orifices. High magnification of the DT revealed a cross-linking layer of mineralized collagen network extending in the peri-intratubular lumen, with scattered globules of matrix vesicles. CP-OCT enabled the realization of rapid initial scanning and image acquisition with high contrast at the micron scale before profound insights into dentin ultrastructures at the nano scale were provided by FESEM. The variations in structural densities of the dental tissues significantly affected the image contrast and helped identify underlying structures.

Detection and analyzing plane of non-cavitated approximal caries by cross-polarized optical coherence tomography (CP-OCT)

OBJECTIVE

The objective was to assess the detection ability and the effect of analyzing plane of CP-OCT for non-cavitated approximal caries.

METHODS

Thirty human extracted premolars were selected based on micro-computed tomography [μ-CT: μ- CT = 0: sound (n = 12), μ-CT = 1/2: caries into outer-/inner-half of enamel (n = 6 each), μ-CT = 3: caries into outer one-third of dentine (n = 6)]. Teeth were mounted in a custommade device to simulate approximal contact, and scanned from the marginal ridge above the contact area. CP-OCT images were analyzed by deepest caries extension from horizontal and coronal planes, and repeated 48-hrs later. Sensitivity, specificity,percent correct, area under the ROC curve (Az), intra-examiner repeatability and correlation with μ-CT were determined.

RESULTS

Sensitivity/specificity/Az for Horizontalplane, Coronal-plane, and Deepest from both planes were 94percent/58percent/0.76,81percent/100percent/0.90, and 94 %/58 %/0.82. Coronal-plane had significantly higher specificity than Horizontal-plane and Deepest (p = 0.004) but Horizontal-plane and Deepest were not different (p = 1.00). Horizontal-plane had significantly lower Az than Deepest (p = 0.048), but Coronal-plane was not different than Horizontal-plane (p = 0.07) or Deepest (p = 0.20). Correlation coefficients were Horizontal-plane (0.53, p < 0.001), Coronal-plane (0.84, p < 0.001), and Deepest (0.66, p < 0.001).

CONCLUSION

Within the limitations of this study, CP-OCT could be used to detect non-cavitated approximal caries. Analysis using the Coronal-plane is superior to the Horizontal-plane.

CLINICAL SIGNIFICANCE

It is challenging to detect non-cavitated approximal caries clinically due to the adjacent tooth. CP-OCT is a nondestructive, no ionized-radiation caries detection technique. CP-OCT seems suitable to detect non-cavitated approximal caries and observing the Coronal-plane appears better than Horizontal-plane.

Optical coherence tomography's current clinical medical and dental applications: a review

Optical coherence tomography (OCT) is a non-invasive investigative technique that is used to obtain high-resolution three-dimensional (3D) images of biological structures. This method is useful in diagnosing diseases of specific organs like the eye, where a direct biopsy cannot be conducted. Since its inception, significant advancements have been made in its technology. Apart from its initial application in ophthalmology for retinal imaging, substantial technological innovations in OCT brought by the research community have enabled its utilization beyond its original scope and allowed its application in many new clinical areas. This review presents a summary of the clinical applications of OCT in the field of medicine (ophthalmology, cardiology, otology, and dermatology) and dentistry (tissue imaging, detection of caries, analysis of dental polymer composite restorations, imaging of root canals, and diagnosis of oral cancer). In addition, potential advantages and disadvantages of OCT are also discussed.