Diagnosis of cracked tooth: Clinical status and research progress

Diagnostic Accuracy of Methods Used to Detect Cracked Teeth

OBJECTIVES

Cracked tooth diagnosis is challenging due to the unknown diagnostic accuracy of tools, resulting in misdiagnosis and suboptimal treatment outcomes. The primary objective of this study was to determine the diagnostic accuracy of four commonly used visual tests in diagnosing cracked teeth based on clinical appearance, independent of patient symptoms. The secondary objective was to assess if clinical experience influences the ability to accurately identify the presence of a crack. The tertiary objective was to assess the ability of the index tests to accurately determine the location of the crack.

MATERIAL AND METHODS

The test sample included 30 teeth extracted due to a suspected crack. Index tests included macrophotography, surgical microscope, transillumination, and DIAGNOcam. Microcomputed tomography (micro-CT) served as the gold standard. Four examiners of varying experience assessed images of each tooth paired with each index test. The examiner's findings were compared against micro-CT to determine the diagnostic accuracy of index tests. The relationship between clinical experience and diagnostic accuracy was explored.

RESULTS

Transillumination demonstrated the highest accuracy (65.3%) and sensitivity (68.8%) for diagnosing cracks. Macrophotography and high-magnification microscope had the highest specificity of 92.9%. Positive predictive value (PPV) was greatest with high-magnification microscope (96.7%). The low-magnification microscope demonstrated the lowest accuracy (52.2%). Intra-rater reliability was moderate to substantial, and inter-rater reliability was fair. Experienced dentists were more accurate in detecting cracked teeth.

CONCLUSIONS

Visual diagnostic methods cannot definitively diagnose cracks. Further studies are required to explore the impact of a combination of tools in diagnosing cracked teeth.

Trueness and depth discrepancy of post-space scans using an intraoral scanner: influence of preparation dimensions: an in vitro study

BACKGROUND

Intraoral scanning of post spaces offers a potential alternative to conventional impressions, but its effectiveness depends on overcoming limitations influenced by post space dimensions.

AIM OF THE STUDY

This study aimed to evaluate the trueness and depth discrepancy percentage of scanned post spaces with different dimensions using an intraoral scanner.

MATERIALS AND METHODS

Twenty single-rooted human maxillary canines were endodontically treated. Teeth were assigned to two post space preparation width groups: N (Ø1.5 mm) and W (Ø1.7 mm) (n = 10 per group). Each width group was further subdivided into two depth subgroups: S (6 mm) and L (10 mm) (n = 5 per subgroup). This resulted in four experimental subgroups: NS (Ø1.5 mm, 6 mm), NL (Ø1.5 mm, 10 mm), WS (Ø1.7 mm, 6 mm), and WL (Ø1.7 mm, 10 mm). Specimens were scanned using the Panda P2 intraoral scanner (IOS), and the obtained STL files were aligned and compared with those from traditional impressions scanned with the InEos X5. Trueness and depth discrepancy percentage were evaluated using reverse engineering software. The data were statistically analysed using a Two-Way ANOVA, followed by multiple pairwise comparisons using Tukey's HSD for each individual factor.

RESULTS

Preparation width had no significant effect on trueness (p > 0.05), whereas increasing preparation depth significantly reduced it. Additionally, a greater preparation width significantly decreased the depth discrepancy percentage, while increasing preparation depth led to a significant increase. A statistically significant, very strong positive correlation was observed between RMS and depth discrepancy percentage (r = 0.898), indicating that greater deviations in trueness were associated with increased depth discrepancies.

CONCLUSIONS

Within the study's limitations, trueness improved by reducing post space depth and remained clinically acceptable for all subgroups. However, increasing depth to 10 mm raised the depth discrepancy beyond the clinically acceptable range, while decreasing width also increased discrepancy.

CLINICAL TRIAL NUMBER

Not applicable.

Characteristics of cracks in posterior teeth and factors associated with symptoms: a cross-sectional practice-based observational study

BACKGROUND

Cracks in teeth are the third most common reason for tooth loss. The primary aim of this study was to identify the patient-specific and tooth-specific characteristics of individuals who presented to a private general dental practice with cracked posterior teeth. The secondary aim was to explore the relationship between the above characteristics and investigate their influence on signs and symptoms.

MATERIALS AND METHODS

A total of 147 records were analysed in terms of patient-specific, tooth-specific and crack-specific characteristics. Initial data analysis involved the use of descriptive statistics and chi-square tests. Stepwise logistic regression was used for model building, and further data analysis was performed using binomial and multinomial logistic regression.

RESULTS

Most cracked teeth were asymptomatic (55.1%) and were not visible before removal of restoration. Unrestored marginal ridges (OR2.89), cracks visible before restoration removal (OR3.04) and cracks involving both the body and cusps of teeth (OR3.11) were associated with cold sensitivity. Not all cracked teeth were positive for the bite test. Molar teeth (OR8.79) and those with amalgam restoration (OR4.81) were associated with intersecting cracks.

CONCLUSION

The presentation of teeth with cracks in general dental practice seems to differ from that reported in the literature from specialist practice.

Human Tooth Crack Image Analysis with Multiple Deep Learning Approaches

Tooth cracks, one of the most common dental diseases, can result in the tooth falling apart without prompt treatment; dentists also have difficulty locating cracks, even with X-ray imaging. Indocyanine green (ICG) assisted near-infrared fluorescence (NIRF) dental imaging technique can solve this problem due to the deep penetration of NIR light and the excellent fluorescence characteristics of ICG. This study extracted 593 human cracked tooth images and 601 non-cracked tooth images from NIR imaging videos. Multiple imaging analysis methods such as classification, object detection, and super-resolution were applied to the dataset for cracked image analysis. Our results showed that machine learning methods could help analyze tooth crack efficiently: the tooth images with cracks and without cracks could be well classified with the pre-trained residual network and squeezenet1_1 models, with a classification accuracy of 88.2% and 94.25%, respectively; the single shot multi-box detector (SSD) was able to recognize cracks, even if the input image was at a different size from the original cracked image; the super-resolution (SR) model, SR-generative adversarial network demonstrated enhanced resolution of crack images using high-resolution concrete crack images as the training dataset. Overall, deep learning model-assisted human crack analysis improves crack identification; the combination of our NIR dental imaging system and deep learning models has the potential to assist dentists in crack diagnosis.

Fracture resistance and failure mode of three esthetic CAD-CAM post and core restorations

BACKGROUND

The rising demand for improved aesthetics has driven the utilization of recently introduced aesthetic materials for creating custom post and core restorations. However, information regarding the fracture resistance of these materials remains unclear, which limits their practical use as custom post and core restorations in clinical applications. AIM OF THE STUDY: This study aimed to evaluate the fracture resistance of three non-metallic esthetic post and core restorations and their modes of failure.

MATERIALS AND METHODS

Thirty-nine single-rooted human maxillary central incisors were endodontically treated. A standardized post space preparation of 9mm length was performed to all teeth to receive custom-made post and core restorations. The prepared teeth were randomly allocated to receive a post and core restoration made of one of the following materials (n=13): glass fiber-reinforced composite (FRC), polyetheretherketone (PEEK) and polymer-infiltrated ceramic-network (PICN). An intraoral scanner was used to scan all teeth including the post spaces. Computer-aided design and computer-aided manufacturing (CAD-CAM) was used to fabricate post and core restorations. Post and core restorations were cemented using self-adhesive resin cement. All specimens were subjected to fracture resistance testing using a universal testing machine. Failure mode analysis was assessed using a stereomicroscope and SEM. The data was statistically analyzed using One-Way ANOVA test followed by multiple pairwise comparisons using Bonferroni adjusted significance level.

RESULTS

Custom PEEK post and core restorations displayed the least fracture load values at 286.16 ± 67.09 N. In contrast, FRC exhibited the highest average fracture load at 452.60 ± 105.90 N, closely followed by PICN at 426.76 ± 77.99 N. In terms of failure modes, 46.2% of specimens with PICN were deemed non-restorable, while for PEEK and FRC, these percentages were 58.8% and 61.5%, respectively.

CONCLUSIONS

Within the limitation of this study, both FRC and PICN demonstrated good performance regarding fracture resistance, surpassing that of PEEK.

Influence of restorative materials on the mechanical properties of maxillary first molars with different degrees of cryptic fractures and defects: A finite element analysis

This study aimed to apply finite element analysis to evaluate the effects of pile materials with different elastic moduli and cement materials on the stress distribution between the remaining tooth tissue and cryptic fracture defects. A three-dimensional finite element model was established for 20 maxillary first molars with hidden fissures and mesial tongue-tip defects. Two levels of hidden cracks and three types of pile and adhesive materials were used in the design. The stress distribution and maximum stress peak in the remaining tooth tissue and crack defects were determined by simulating the normal bite, maximum bite, and lateral movement forces. When titanium posts, zinc phosphate binders, and porcelain crowns were used to repair the two types of deep cracked teeth, the maximum principal stress at the crack and dentin was the smallest. As the crack depth increased, the maximum principal stress of the residual dentin and crack defects increased.