Investigation of validity and inter examiner agreement of quantitative light induced fluorescent images in diagnosing cracked teeth

Son S., Kim J., Park J.

The aim of this case report was to discuss the clinical application using a quantitative light-induced fluorescent (QLF) device for the diagnosis and treatment of a cracked tooth as visualizing the tooth's crack. A 39-year-old woman visited a dental hospital complaining of throbbing pain on tooth #36. Observation of the tooth with naked eyes showed that tooth had a ceramic restoration with no specific findings. QLF device's images around the restoration, and after removal of the restoration were taken. In the QLF image after removal of the restoration, clear red-fluorescent crack line was shown, indicating that microorganism had penetrated along the crack path. During root canal treatment, the QLF image of the inside of the pulp chamber showed a pattern in which the crack line progressed into the tooth. During the treatment of the cracked tooth, the crack line was removed as much as possible using the fluorescent information obtained by the QLF device, and crack lines of fluorescence images quantitatively analyzed using a QLF's software. Images acquired with the QLF device can provide useful information for detecting crack lines, recording the treatment process, and restorative management of cracked teeth.

Kakka A., Gavriil D., Whitworth J.

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

de Toubes K.M., Soares C.J., Soares R.V., Côrtes M.I., Tonelli S.Q., Bruzinga F.F., Silveira F.F.

Cracked teeth frequently require protective adhesive restorations. This long-term, longitudinal retrospective clinical study aimed to evaluate the factors influencing the success and survival rates of cracked teeth with crack lines (CLs) in different directions when restored early with onlays or full-coverage crowns.The dental records of 71 patients with a total of 86 cracked teeth with different pulpal and periapical diagnoses and with follow-ups spanning over 1-11 years were included. Data regarding the demographics; clinical symptoms and signs; bruxism; occlusal interferences; eating habits; pulpal and periapical diagnoses; number, direction, location, and extent of CLs; probing depth; and coronary condition before and after the placement of definitive restorations were collected. Univariate associations between tooth survival and explanatory variables were assessed. The long-term survival rate was estimated using Kaplan-Meier analysis and the log-rank test. A multivariate analysis was performed using Cox regression analysis.The overall success rate was 93.0%, and the overall survival estimates of cracked teeth restored early were 98.6%, 94.9%, and 55.9% at the 1-, 5-, and 11-year follow-ups, respectively. The direction of the CLs did not influence the survival of the tooth. No significant association was observed between the type of tooth, probing depth, root canal treatment, and tooth loss (P > .05). The multivariate analysis showed that previously treated cracked teeth (P < .05), the provision of onlay restorations (P < .05), and the placement of posts (P < .05) had higher correlations with tooth loss. Additionally, the placement of full-coverage crowns resulted in lower tooth loss compared with the placement of onlays (P < .05).Previous endodontic treatment in teeth that subsequently develop CLs has a negative impact on the survival rate of the teeth. Moreover, early placement of full-coverage crowns should be implemented for cracked teeth regardless of the direction or the number of CLs because it is associated with a higher cracked tooth survival rate.

Son S., Kim J., Park J.

Abstract Diagnosing a cracked tooth is a challenge for dental clinicians. This report describes the use of a quantitative light-induced fluorescent (QLF) device that detects fluorescence reactions with visible light (405 nm) to visually identify microscopic tooth cracks during the diagnosis and treatment of cracked teeth that caused pulp disease. Fluorescence images of the occlusal surface, before and after removal of the restoration, and inside of the access cavity for root canal treatment were obtained using an intraoral capture-type QLF device (Q-ray penC; AIOBIO, Seoul, Korea). The device provided visual information such as enhanced magnification and fluorescent images to identify cracks on the exterior of the tooth, around restorations, and inside the cavity after removal of the restoration by a simple image capture process. The device was able to demonstrate the existence of the crack line and to predict the depth of cracks during treatment.The QLF device showed a potential benefit in the diagnosis and characterization, including the location and depth, of tooth cracks.

Oh S.H., Lee S.R., Choi J.Y., Choi Y.S., Kim S.H., Yoon H.C., Nelson G.

The aim of this study was to present an optimal diagnostic protocol by comparing and analyzing a conventional examination and the quantitative light-induced fluorescence (QLF) technique. Selected were 297 teeth of 153 patients to take QLF images and bitewing radiographs. Occlusal dental caries, proximal dental caries and cracks were evaluated and scored using QLF, X-ray and/or visual criteria. The sensitivity, specificity, and area under the curve (AUC) of a receiver operating characteristic analysis were calculated. Two fluorescence parameters (|ΔFmax| and ΔRmax) were utilized to evaluate the fluorescence pattern according to the severity of lesions based on QLF or X-ray criteria. QLF showed higher scores for detecting occlusal dental caries and cracks than the conventional method. ΔRmax increased more clearly than ΔFmax did with occlusal dental caries. The |ΔFmax| values of occlusal dental caries, proximal dental caries and cracks showed good AUC levels (0.84, 0.81 and 0.83, respectively). The ΔRmax of occlusal dental caries showed the highest AUC (0.91) and the ΔRmax of proximal dental caries showed a fail level (0.59) compared to bitewing radiographs. The QLF image could visualize and estimate the degree of occlusal dental caries or cracks. Consequently, the QLF technique may be an adjunct tool to conventional methods for the detection of occlusal caries and peripheral cracks.

Gao A., Cao D., Lin Z.

Cone-beam computed tomography (CBCT) has been widely used in diagnosis of vertical root fractures (VRFs) in recent years. According to the American Association of Endodontists (AAE) classification, there are five types of cracked teeth and VRF is one of them. Due to the variability and overlapping of the cracks and fractures, some narrow fractures on the roots of VRFs could not be detected by CBCT, and some wide cracks on the crown of cracked teeth could be detected by CBCT. In this review, we firstly discussed the value of CBCT in the diagnosis of the AAE five types of cracked teeth and presented CBCT manifestations of some typical cases. Secondly, we summarized the factors influencing the diagnosis of cracks/fractures using CBCT, namely, CBCT device-related factors, patient-related factors, and evaluator-related factors. The possible strategies to improve the diagnostic accuracy in the clinic practice are also discussed in this part. Finally, we compared the differences of root fractures with lateral canals and external root resorption on CBCT images.

Rosen E., Volmark Y., Beitlitum I., Nissan J., Nemcovsky C.E., Tsesis I.

The objective of this study was to evaluate potential risk factors, including the placement of dental implants, for the development of tooth cracks. A series of 212-patients, who were referred for endodontic treatment, were retrospectively screened, of which 72 (34%) patients had been diagnosed with 80-cracked teeth confirmed with an operating microscope. These patients had an average age of 53-years and were equally distributed between genders. Forty-one percent of the cracked teeth were diagnosed after the placement of dental implants, with an average of 3-implants per patient. Seventy percent of the cracks were diagnosed more than 1-year after implant loading. Implant placement was associated with higher odds of having multiple cracks (OR = 9.78, CI:2.320, 41.216)(p < 0.05). The proportion of cracked premolars was relatively high (30%), and most cracked teeth (79%) were vital and with a normal periapical diagnosis (86%). Most cracked teeth (71%) had an amalgam restoration, and teeth restored with amalgam were at a higher risk of having multiple cracks (p < 0.05). Clinicians should be aware of a common profile of endodontic patients with multiple cracks in a non-endodontically treated premolar, restored with an amalgam restoration, which was diagnosed with the cracks more than 1-year after reconstruction utilizing multiple implants.

SUESE K.

Jun M., Park S., Lee E., Kim B., Kim B.

The aim of this case report was to describe the process of diagnosis and treatment of a cracked tooth using quantitative light-induced fluorescence (QLF).A 43-year-old male presented at our dental clinic with a complaint of cold pain in #17 tooth. A routine oral examination with radiography was performed for evaluation of the oral condition and treatment planning. Additionally, QLF image capture was performed using Qraycam and Qraypen (AIOBIO, Seoul, Republic of Korea), to collect white-light and fluorescence images. The #17 tooth was observed to have a crack line, showing red fluorescence, from the distal to mesial aspect on the occlusal surface. Even though there was no visible root fracture in the radiographic image, bone loss was observed. Therefore, we performed periodontal treatment. One month later, a root canal treatment was performed because the patient still complained of pain in the #17 tooth. During this treatment, one fluorescent image and one white light image set was captured with the Qraypen. A crack line showing red fluorescence was observed, while the line was not visible to the naked eye. After treatment, the patient has had no complaint related to this tooth for 3 years until today.Clinically, use of QLF confirmed the presence of a crack before and during a root canal treatment. Therefore, it is postulated that the QLF technology could objectively facilitate the diagnosis and treatment of a cracked tooth.

Coelho M.S., Card S.J., Tawil P.Z.

Several recent studies have evaluated the presence of dentinal defects after root canal preparation in extracted human teeth by using the root sectioning methodology. The objective of this research was to investigate whether light-emitting diode (LED) transillumination enhances the visualization of dentinal defects by using a root sectioning methodology.Forty mesial roots of mandibular molars were sectioned at 3, 6, and 9 mm from the apex with a low-speed saw under water cooling. Microscopic pictures of the specimens were taken by using ×19.2 magnification for the 3-mm slice and ×12.8 magnification for the 6- and 9-mm slices. The LED transillumination was done by positioning an LED probe at 4 different locations (mesial, distal, buccal, and lingual). The root canal lumen was masked, and 2 independent evaluators assessed the presence of dentinal defects on the non-LED and LED images. The number of dentinal defects was recorded, and χ(2) test was used for statistical analysis (P < .05).The number of slices presenting dentinal defects at 3, 6, and 9 mm were 2 (5%), 1 (2.5%), and 1 (2.5%), respectively, for the non-LED assessment and 8 (20%), 10 (25%), and 9 (22.5%), respectively, for the LED assessment. Overall, 4 of the specimens (10%) presented dentinal defects without LED evaluation, and 19 of the specimens (47.5%) presented dentinal defects with LED evaluation. This difference was statistically significant (P < .05).LED transillumination enhanced the visualization of dentinal defects in uninstrumented roots. The results from previous studies that used the traditional non-LED sectioning methodology should be evaluated with caution.

Jun M., Ku H., Kim E., Kim H., Kwon H., Kim B.

The ability to accurately detect tooth cracks and quantify their depth would allow the prediction of crack progression and treatment success. The aim of this in vitro study was to determine the capabilities of quantitative light-induced fluorescence (QLF) technology in the detection of enamel cracks.Ninety-six extracted human teeth were selected for examining naturally existing or suspected cracked teeth surfaces using a photocuring unit. QLF performed with a digital camera (QLF-D) images were used to assess the ability to detect enamel cracks based on the maximum fluorescence loss value (ΔFmax, %), which was then analyzed using the QLF-D software. A histologic evaluation was then performed in which the samples were sectioned and observed with the aid of a polarized light microscope. The relationship between ΔFmax and the histology findings was assessed based on the Spearman rank correlation. The sensitivity and specificity were calculated to evaluate the validity of using QLF-D to analyze enamel inner-half cracks and cracks extending to the dentin-enamel junction.There was a strong correlation between the results of histologic evaluations of enamel cracks and the ΔFmax value, with a correlation coefficient of 0.84. The diagnostic accuracy of QLF-D had a sensitivity of 0.87 and a specificity of 0.98 for enamel inner-half cracks and a sensitivity of 0.90 and a specificity of 1.0 for cracks extending to the dentin-enamel junction.These results indicate that QLF technology would be a useful clinical tool for diagnosing enamel cracks, especially given that this is a nondestructive method.

Han S., Kim B., Ko H., Kwon H., Kim B.

The aim of this study was to evaluate validity and reliability of autofluorescence-based plaque quantification (APQ) method.The facial surfaces of 600 sound anterior teeth of 50 subjects were examined. The subjects received dental plaque examination using Turesky modified Quigley Hein plaque index (QHI) and Silness & Löe plaque index (SLI). The autofluorescence images were taken before the plaque examination with Quantitative Light-induced Fluorescence-Digital, and plaque percent index (PPI) was calculated. Correlation between two existing plaque indices and the PPI of the APQ method was evaluated to find which level of plaque redness on tooth (ΔR) by the APQ method shows the highest correlation. The area under the ROC curve (AUC) analysis and intra- and inter-examiner reliability tests were performed.The PPIΔR20 of the APQ method showed a moderate correlation with two existing plaque indices (rho of QHI=0.48, SLI=0.51). This methodology fell in the fair category and it had an excellent reliability. The APQ method also showed possibility to detect heavy plaque with fair validity.The APQ method demonstrated excellent reliability, and fair validity, compared with 2 conventional indices. The plaque quantification described has the potential to be used in clinical evaluation of oral hygiene procedures.

Ricucci D., Siqueira J.F., Loghin S., Berman L.H.

The diagnosis and treatment planning of cracked teeth depend on the understanding of how cracks affect the surrounding tissues. This study evaluated the dentin and pulp conditions in teeth affected by cracks and attrition.Specimens under investigation included 12 cracked posterior teeth and 8 teeth with severe attrition. These teeth were obtained consecutively in a private practice and were extracted for reasons not related to this study. Teeth were processed for histopathologic and histobacteriologic analyses.Cracks were histologically detected in all specimens, including the teeth with severe attrition. The cracks in all teeth were colonized by bacterial biofilms. One tooth showed several craze lines in the enamel, one of which reached dentin to a shallow depth. In some teeth, the crack ended in the dentin. Dentinal tubules were invaded by bacteria, especially when the crack extended perpendicularly into the dentin. Severe accumulations of inflammatory cells were present in the pulp zone subjacent to tubules involved with the crack. In many cases, the crack extended to the pulp, leading to reactions with intensities ranging from acute inflammation to total pulpal necrosis. Symptoms occurred in most cases in which the pulp was affected. In some cases, polymorphonuclear neutrophils were seen migrating from the pulp into the crack space and facing the bacterial biofilm located therein. Severe pulp reactions were also observed when the crack extended to the pulp chamber floor.Cracks are always colonized with bacterial biofilms. The pulp tissue response varies according to the location, direction, and extent of the crack.

Lee E., Kang S., Ko H., Kwon H., Kim B.

This study evaluated whether Quantitative Light-induced Fluorescence-Digital (QLF-D) can detect the levels of cariogenicity of dental microcosm biofilms by assessing the red fluorescence intensity. Dental microcosm biofilms were initiated from human saliva on bovine enamel discs. Biofilms with various levels of cariogenicity were then grown in artificial saliva supplemented with sucrose at different concentrations (0.05%, 0.1%, 0.2%, and 0.5%) in 24-well microplates. After 10 days, fluorescence images of the biofilms were captured by the QLF-D to analyse the red fluorescence intensity, which was quantified as the red/green ratio ( R / G value). The supernatant pH was also measured, as well as the total and aciduric bacteria counts of the collected biofilms. Mineral loss in enamel was also evaluated by calculating the percentage of surface microhardness changes (%SHC). The R / G values of the biofilms differed significantly with the sucrose concentration ( p < 0.0001), increasing consistently as the sucrose concentration increased from 0.05% (=0.91) to 0.5% (=2.56). Strong correlation was identified between the R/G value and the number of aciduric bacteria ( r = 0.83, p < 0.0001), supernatant pH ( r = −0.95, p < 0.0001), and %SHC ( r = 0.90, p < 0.0001). The red fluorescence as observed by the QLF-D was correlated with the cariogenic properties of dental microcosm biofilms in vitro , which indicates that this device can be used to detect the levels of cariogenicity of a dental biofilm. The QLF-D is able to assess the cariogenic levels of dental plaque based on the intensity of red fluorescence.

Seo D., Yi Y., Shin S., Park J.

AbstractIntroduction The purpose of this study was to analyze the characteristics, distribution, and associated factors of longitudinal fractured teeth according to the well-defined criteria of the American Association of Endodontists (AAE). Methods One hundred seven teeth with longitudinal fracture from 103 patients were diagnosed and analyzed. The patients' signs, symptoms, age, and sex were noted as well as the tooth number, dental arch, filling materials, size/classification of restoration, crack direction, pulp vitality, whether the patient had undergone endodontic treatment, bite test results, percussion test results, wear facet, and periodontal pocket depth. Results Eighty-seven teeth were diagnosed with a cracked tooth (81.3%), 14 were diagnosed with vertical root fracture (VRF, 13.1%), 4 had a split tooth (3.7%), and 2 had a fractured cusp (1.9%); 82.2% showed a sensitive reaction on the bite test. Longitudinal tooth fractures were observed most frequently in patient in their 40s. The upper first molar (28.0%) was most frequently cracked, followed by the lower first molar (25.2%), the lower second molar (20.6%), and the upper second molar (16.8%). Most longitudinal tooth fractures (72.0%) occurred mainly in restored teeth, whereas only 28.0% were found in intact teeth. Compared with resin (4.7%) or porcelain (0.9%), the use of nonbonded inlay restoration materials such as gold (20.5%) or amalgam (18.7%) increased the occurrence of longitudinal tooth fractures. Out of 107 of longitudinal fractured teeth, 33 (30.8%) were treated endodontically and 74 (69.2%) were not. VRF was associated with endodontic treatment. Conclusions The bite test is most reliable for reproducing symptoms. The combined use of various examination methods is recommended for detecting cracks and minutely inspecting all directions of a tooth.