|Year : 2017 | Volume
| Issue : 1 | Page : 22-27
Innovative technology for caries detection and validation histologically to support restorative dentists and researchers' decision-making in vitro
Manal Rahma Alammari
Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
|Date of Web Publication||14-Feb-2017|
Manal Rahma Alammari
Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, King Abdulaziz University, P.O. Box 80209, Jeddah 21589
Source of Support: None, Conflict of Interest: None
Background and Aim: The most common gold standard used for caries research is a histological evaluation of dental hard tissues. Intraoral camera (quantitative light-induced fluorescence [QLF]) is one of the newer technologies. It is one way of assessing light interactions with dental tissues that require measuring and recording of emitted light and evaluate the quantity of mineral loss. The aim of this study was to evaluate, validate, and utilize this intraoral device to identify more efficient and objective procedures for the histological examination and diagnosis.
Materials and Methods: Freshly extracted human teeth (n = 50), covering various caries' lesions range, were collected. Radiograph was taken, and the International Caries Detection and Assessment System II was used. Each tooth was sectioned into halves which was examined with a stereomicroscope and scored using a five-point ranked histological scoring system. Image of each half was then taken by digital microscopy camera. Then, two halves were imaged and analyzed using QLF camera.
Results: Average fluorescence loss (ΔF) correlated positively with histology. The correlation was 0.781 and significant at the 1% level. QLF images provide a superior picture regarding caries progression into dental tissues with advantages of enhanced visual appearance. It is clear to differentiate whether the lesion is limited to enamel or extends into dentine and the degree of proximity to pulp. In some images, red fluorescence observed which might indicate bacterial invasion.
Conclusion: QLF is a useful instrument to support the level of dental caries involvement into histological sections of dental tissue, and hence, it will help in clinical diagnosis. Moreover, it can be used as an educational tool for undergraduate dental students as well as in future research.
Keywords: Caries, diagnosis, histological sections, intraoral camera, lesion, light
|How to cite this article:|
Alammari MR. Innovative technology for caries detection and validation histologically to support restorative dentists and researchers' decision-making in vitro. Saudi J Oral Sci 2017;4:22-7
|How to cite this URL:|
Alammari MR. Innovative technology for caries detection and validation histologically to support restorative dentists and researchers' decision-making in vitro. Saudi J Oral Sci [serial online] 2017 [cited 2021 Jul 24];4:22-7. Available from: https://www.saudijos.org/text.asp?2017/4/1/22/200144
| Introduction|| |
The treatment philosophies for caries lesions progressively moved toward the preventive treatment of enamel lesions where the lesions can have an opportunity to reverse.,, To apply the preventive treatment, caries lesions need to be detected at their early phase precisely. Teeth have many perceived to be of chief importance. Nowadays, many patients are unwilling to accept the loss of their teeth.
Adult dental health continues to improve in a number of industrially developed countries.,, From a prosthodontic perspective, patterns of tooth loss are changing, with steady reductions in the numbers of edentulous individuals , and associated increases between older age groups who are partially dentate and susceptible to dental caries accordingly., Since these people would have experienced higher disease levels historically, many of the retained teeth would already have been restored. Against this background, changing dental demographic outlines, there are also changes in population demographics.
Nevertheless, being dentate is an advantage in terms of oral functional benefits only if the inherent risks of a few poorly distributed, perhaps structurally and/or biologically compromised teeth, can be minimized to do the prosthodontic treatment. The prevention of demineralization, the promotion of remineralization of the early phases of dental caries together with minimal restorative intervention, have become the mainstay of contemporary dentistry  that help in the field of dentistry and particularly prosthodontics.
However, these goals can only be achieved if caries is detected at an early stage, perhaps with an instrument capable of supporting the dentists in their decision-making objectively.
It is important to proceed in dental caries diagnosis research to develop a diagnostic method and tool that gives the best outcome for dental patients. One recent development proposed to decrease the subjectivity, increase the sensitivity when evaluating caries activity is The International Caries Detection and Assessment System (ICDAS). Caries activity criteria used as part of ICDAS depend on the physical characteristics of tooth surfaces examined.
There are large variations on this matter and at its simplest; the teeth are hemisectioned at the area that is going to be inspected. When examining histological sections of teeth, a high resolution of fine structures is vital. Research into the hard tissues of enamel and dentine requires a histological technique that conserves this mineralized tissue and takes into justification the hardness and brittleness of the tissues.,
Quantitative light-induced fluorescence (QLF) is a visible light system that offers the opportunity to detect early caries using two forms of fluorescent detection (green and red); it may also be able to determine if a lesion is active or not. QLF uses the intrinsic fluorescence of the teeth. The resultant autofluorescence of human enamel is then detected by filtering out by a small intraoral camera. This produces an image that comprised only green and red channels and the enamel predominate color is green.,
Many in vitro studies and some in vivo studies had been conducted and published , and it has been possible to quantify the mineral loss and gain. QLF technology would be a useful clinical tool for diagnosing, especially given that this is a nondestructive method. In addition, histological studies proved that loss of fluorescence measured by QLF is an excellent parameter for mineral loss expression in carious lesions., To the best of author's knowledge, no one uses it as a histological examination tool to detect and quantify the mineral loss in teeth histological sections. This provides us with a quick and objective way until the work of Alammari et al. in 2013 proved that. It can be concluded that QLF provides additional chair-side information and quantification, not currently available using conventional clinical methods.,,
That is, the aim of this study was to evaluate, validate, and utilize the new intraoral camera to identify more efficient and objective measures for the histological examination for clinical use, research investigation, and dental education.
| Materials and Methods|| |
The Research Ethics Committee at King Abdulaziz Dental Hospital approved this study. The study focused on the testing of various diagnostic methods to compare them, as well as to validate them histologically, commonly use stereomicroscopy to develop applications for teaching and basic research purposes. Validation studies have been performed and reviewed recently by Pretty et al. In this study, the QLF analysis compared together with stereomicroscopy in vitro. Freshly extracted human teeth (n = 50), covering various caries range, were collected from patients undergoing extractions from the dental hospital after patients read the information sheet and sign the consent. Each tooth was thoroughly cleaned. The teeth were stored in distilled water with thymol crystals (0.1% w/v) (GPR™, Poole, England) and kept in a dark, cold room at 6°C until analyzed. Requirements of the Human Tissue Act (HTA) were met in HTA, 2004.
ICDAS II visual scoring system was used for every surface for each tooth. In this study, a visual code system (VCS) was developed by the use of ICDAS II; visual assessment resulted in a five-digit score of VCS for each tooth consisting of the single-digit ICDAS II scores for each surface. As the number increases, the severity of dental caries increases.
Periapical radiographs were taken for each. A radiographic index (Ekstrand et al., 1997) was used. Next, the root component was removed at (enamel-cement junction) using a handpiece with a diamond disk (Skillbond, UK). Subsequently, each crown was sectioned using a diamond wire saw (Well Wire Saw, The Precision Diamond Wire Saw Series 3, Switzerland) from mesial to distal through the crown of the tooth into two halves. Each half was examined with a stereomicroscope (SMZ 10, Nikon) and scored using a five-point ranked histological scoring system developed by Ekstrand, Ricketts, and Kidd (ERK). An image of the half of the tooth indicating deeper carious involvement was then taken using a digital microscopy camera (Moticam 2300, 3.0 M Pixel, China). Again, each section was scored twice.
The data were statistically analyzed using SPSS for Windows software (version 184.108.40.206, Chicago, IL). After the descriptive analysis of the data, ΔF, ΔQ, they were compared with ICDAS II for the whole values and for the mean of each parameter for each tooth surface by the use of box plots. Quantitative data were described by means, median, and standard deviation.
Spearman's correlation coefficient was employed to compare QLF values, ICDAS II scores, and histology scores on the tooth surface. On all the surfaces of the teeth, for each ICDAS II score, the confidence intervals for green fluorescence loss and red fluorescence (RF) level were determined and translated into a QLF average green fluorescence loss and RF level index. Specificity and sensitivity were calculated as well as the quality of the intra-examiner reproducibility using a kappa statistic.
| Results|| |
Each image was analyzed by a single examiner after comprehensive calibration for white spot (WS) and RF. Analysis of the tooth surfaces was conducted. The lesion was marked on the screen to ensure analysis of the areas determined as caries. For every lesion, the ΔF (%), the area of the lesion (mm 2), and ΔQ (the product of these two parameters, % mm 2) were calculated by the software. For green fluorescence loss, a border was drawn around the lesion and from this, the sound tissue fluorescence values were determined. The comparison of sound tissue fluorescence levels with the actual fluorescence values at a threshold of 5% level was done. The software automatically calculated the average fluorescence loss.
The sound fluorescence values inside the patch were reconstructed; thus, the decrease in fluorescence was determined by calculating the percentage difference between real and reconstructed fluorescence surface. The ΔQ, ΔF, and WSs values were recorded.
Regarding transverse microradiography (TMR) analysis, the microradiograph plates were examined with a Leica microscope (Leica, Brighton, England) with images captured by means of a CCD video camera (Sony, Tokyo, Japan) linked to a computer at a magnification of ×20/0.40. The sections were analyzed by means of a software package (TMRW version 1.22, Inspektor Research System BV, Amsterdam, The Netherlands) after specimen preparation. All data gathered from different indices, systems, and techniques employed in this study and exported into word files for each tooth.
ICDAS II with ΔF showed that ΔF at the 5% threshold level correlated positively with ICDAS II visual index. It can be clearly gotten that as the ICDAS II increased, the average green fluorescence loss increased; therefore, as the severity of dental caries increases, the fluorescence loss increases. The data presented show a positive relation between ICDAS II and maximum fluorescence loss which correlated more with ICDAS II (0.795) than average ΔF (0.772). This was significant at the 1% level. ICDAS II with ΔQ (area ×ΔF) correlated positively with ICDAS II visual index, with a correlation of 0.710, which was significant at the 1% level.
Concerning the histology, there was a correlation of 0.753 between histology (gold standard) and ΔF values obtained from the analysis of the occlusal surfaces of the teeth as shown in [Figure 1]; the correlation was significant at the 1% level. Moreover, there was a correlation of 0.696 between histology and maximum fluorescence loss on the occlusal surfaces of the teeth, which was significant at the 1% level. [Figure 2] shows the amount of demineralization extension into dental tissues and some RF which is not be identified by the dentist's clinical examination.
|Figure 2: Overview of quantitative light-induced fluorescence occlusal with corresponding clinical and histological appearance. (a) Natural tooth surface. (b) Tooth under quantitative light-induced fluorescence Camera. (c) Histological classification under a microscope (d) Tooth's histological section under QLFconditions|
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ICDAS II with histology on the occlusal surfaces, the correlation in which histological depths corresponded to the visual scores ICDAS II was significant. On the occlusal surfaces, radiographs correlated less perfectly with ICDAS II (0.670), ΔF (0.601), and histology (0.591).
About the TMR, the method has been used for the confirmation of the presence of demineralization as shown in [Figure 3].
|Figure 3: Transverse microradiography for the confirmation of the presence of demineralization|
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| Discussion|| |
To guide researchers and clinicians in the appropriate selection and use of new technologies, latest methods need validation and evaluation with established techniques and have to be feasible for clinical application and use in addition to facilitate its practice by the dental clinician and students to understand the information and numbers produced by its software. It is particularly important to improve and enhance the detection of dental caries in its early stages to allow intervention of preventive regimes to reduce the degree of invasive restorative treatment. Since caries diagnostic research is ultimately aimed at maintaining and improving oral health care, it is the researchers' aim that knowledge and tools are transferred and applied for clinical dentistry. Therefore, there should be an equilibrium between the effort in caries diagnostic research and the application of research results in dental health care.
Conventional clinical visual methods of caries detection of macroscopically integral occlusal surfaces have been shown to have relatively poor sensitivity values, well below 30%. The ICDAS II was developed recently.
The previous studies have shown that the Spearman's correlation coefficient for five-point visual examination was ranged between 0.78 and 0.93. In this study, Spearman's correlation coefficient for ICDAS II with ERK histological scores was 0.800, and it was generally excellent representing a strong relationship between two variables. Intra-examiner reproducibility for the visual ICDAS II examination in this study was kappa = 0.81. To date, little has been published on the visual ICDASII system; on the other hand, a recent study which also used the ICDAS II system found kappa values of 0.79 and 0.78, which were quite similar. Using a five-point scoring system, 0.81 for the intra-examiner agreement was observed.
In other studies, using the same system, kappa values of 0.62 for intra-examiner reproducibility  and 0.69 were achieved. The sensitivity and specificity of ICDAS II with the histological score were high. Using the ICDAS II and ERK histological threshold allowed comparison with previous work, where higher sensitivity (0.94) and specificity (0.89) were obtained. In the most recent study, where ICDAS II and ERK histological threshold used,, a mean sensitivity of 0.60 and a mean specificity of 0.90 were obtained. Intrareproducibility of histology scores in this study was of kappa = 0.79 which was a substantial agreement.
It will encourage the use of the ICDAS II system so that the dental professionals will look closely for thefirst visual changes on tooth surfaces as this system meets the requirements of validity and reliability.
Radiography is a well-accepted and fundamental part of diagnostic and management procedures. It is linked with the unavoidable risks of ionizing radiation. In this study, radiographs correlated with histology on occlusal surfaces (0.591) which are similar to the previous findings (0.54).
This confirms that this technique has been shown to perform poorly in the detection of caries, especially caries on the occlusal surfaces. On the other hand, the visual scoring index correlated well with radiographs (0.670 on occlusal, 0.510 on buccal, 0.590 on the lingual, 0.610 on mesial, and 0.510 on the distal surfaces).
A standard analysis technique was employed to reduce the subjectivity. QLF parameters which linked with histology are the most useful comparison if early detection of dental caries, early intervention, and minimal dental tissue destruction is to be achieved.
RF can be seen anywhere in the mouth but more often in plaque retention sites, and the absence of RF is an indicator of a clean cavity.
It has been suggested that lesions that show RF were active and have the potential to develop into more advanced lesions. Hence, RF should be used as a secondary measure only.
In this study, the correlation between the histology and ΔF was similar to that observed by Higham et al., 2003. The index developed by the group was not validated; however, in this study, the index developed which used a larger sample size, a greater variety of techniques, newer version of QLF software, and compared with other more recent indices such as ICDAS II.
To confirm the quantitative nature of QLF, measurements in relation to an accepted “gold standard” were made. A high sensitivity and specificity were found with histology. It can be seen that the QLF technique performed better in the early stages of dental caries. These findings suggest that the device is useful to distinguish and sort early lesions from sound tissues, where visual detection is difficult, and this reflects the clinical potential of this technology.
Difficulties arise when the TMR technique is used since there is often an irregular or interrupted surface layer on the specimen. The TMR technique is very sensitive and requires a lot of careful preparation and is time consuming, using this technique; it only provides a snapshot of the lesion at a particular stage in its dynamic development. and to illustrate that TMR images showed surface softening and subsurface lesion and helped to confirm the observation detected.
QLF images of tooth sections were found to provide a good general picture regarding the caries disease progression into the dental tissues with the advantages of the contrast and the enhanced visual appearance. It is clear to distinguish whether the lesion is limited to the enamel or extends into dentine and the degree of proximity to the pulp.
The current QLF system is adapted to be used in the clinic since it is compact, not difficult to master, easy to clean, portable, and maintain infection control between patients.
A challenging issue confusing dentists on a daily basis is deciding whether preventive intervention or a combination of preventive and restorative intervention is required. For this reason, a device such as QLF with its relatively high sensitivity and specificity is needed. However, it should not lead to the overdiagnosis of caries and possible overtreatment.
| Conclusion|| |
The results of this study suggest that QLF is appropriate for use in identifying dental caries and demineralization in early stages. The current practice in dentistry has evolved to offer a minimally invasive approach, in which caries is managed by deferring operative involvement for as long as possible. Therefore, QLF will have a significant future role in modern dental caries management. It can be concluded from the present investigation that QLF was able to identify caries on all tooth surfaces and differentiate between lesions of varying severity particularly during the early stages of the disease. It is used to examine the occlusal surfaces without the need for probing and avoid the risks associated using the dental explorer. It is anticipated that QLF will be a valuable tool in routine clinical practice and it may also reduce the patient's exposure to ionizing radiation, minimizing human error, allow follow-up comparisons, and greater reproducibility.
Likewise, quantification of depth is more practical in dental caries diagnosis for the reason that vision estimates contour and size much better than depth. Optical quantification methods have the advantage of simplicity, easy considerate, familiar acceptance, and reduced subjectivity.
QLF is nondestructive, noninvasive, nonionizing, uncomplicated to master, and offers the dental clinicians and researchers a quantifiable research tool which produces archivable data.
A list of in vitro caries diagnostic studies published between 1996 and 1999 shows that stereomicroscopic inspection of tooth sections (histology) is the most appropriate technique for a gold standard by Downer, 1975. This study examines novel technologies and the research supporting their use. Techniques based on visual, optical, radiographic, and some emerging technologies are discussed to aid histological examination.
To all the people who allow me to use the laboratory facilities and the devices during summer to run this interesting and challenging study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]