"THE CORRELATION OF CRACK LINES AND DEFINITIVE RESTORATIONS WITH THE SURVIVAL AND SUCCESS RATES OF CRACKED TEETH: A LONG-TERM RETROSPECTIVE CLINICAL STUDY"

Validity of quantitative values of quantitative light-induced fluorescent (QLF) device for pulp diagnosis of teeth with cracks

INTRODUCTION

The Quantitative Light-Induced Fluorescence (QLF) device provides both the visual information of crack lines on tooth surfaces and quantitative values for fluorescence reactions. The aim of this study was to evaluate the correlation and assess the usefulness of QLF quantitative values in pulp diagnosis of teeth with cracks.

METHODS

Pulp diagnosis was performed on 76 teeth with cracks according to the American Association of Endodontics's guidelines, and their QLF images were captured. The crack lines of the QLF images were quantitatively analyzed using the QLF software CrazeLineWizard01. QLF quantitative values (ΔF: fluorescence loss unit, ΔFmax: maximum of fluorescence loss unit, ΔR: red fluorescence gain unit, ΔRmax: maximum of red fluorescence gain unit) according to the pulp diagnosis of teeth with cracks were analyzed using one-way ANOVA. Multinomial logistic regression analysis was conducted to calculate the prediction of pulp diagnosis on QLF quantitative values. The correlation between the predicted pulp diagnosis and the clinical pulp diagnosis was compared using Pearson's correlation coefficient.

RESULTS

ΔF and ΔF max decreased with the progression of pulp disease in cracked teeth, while ΔR and ΔR max increased. Significant differences were found between irreversible pulpitis and pulp necrosis (p < 0.05). Pearson correlation coefficients between predicted and clinical pulp diagnosis based on multinomial logistic regression analysis of QLF quantitative values ranged from 0.699 to 0.806. The accuracy of prediction​​was up to 82.1 % for reversible pulpitis, 73.1 % for irreversible pulpitis, and approximately 80.0 % for pulp necrosis.

CONCLUSIONS

The quantitative values from the QLF device demonstrate its potential for predicting the severity of pulp disease caused by tooth cracks.

CLINICAL SIGNIFICANCE

The quantitative values of QLF images acquired with a QLF device, which provide visual information on crack lines of teeth through fluorescence reactions on the tooth surface, showed a significant correlation and predictive value for pulp diagnosis as pulp disease progressed in teeth with cracks.

Position statement on longitudinal cracks and fractures of teeth

This position statement is a consensus view of an expert committee convened by the European Society of Endodontology (ESE). The statement is based on current clinical and scientific evidence as well as the collective reflective practice of the committee. The aim is to provide clinicians with evidence-based, authoritative information on the aetiology, clinical presentation, and management of cracks and fractures that typically manifest along the long axis of the crown and/or root.

Evaluation of mechanical and thermal stress in an endodontically treated cracked premolar with three restorative designs: 3D-finite element analysis

PURPOSE

We aimed to analyze the influence of different designs (inlay, onlay, and crown) on stress distribution and crack propagation in an endodontically treated cracked premolar.

METHODS

Three-dimensional (3D) finite element analysis (FEA) was employed to model an endodontically treated cracked premolar with three different restorations (inlay, onlay, and crown). Six types of loadings (vertical loading of 600 N; hot thermal-600 N vertical coupling loading; cold thermal-600 N vertical coupling loading; oblique loading of 200 N; hot thermal-200 N oblique coupling loading; cold thermal-200 N oblique coupling loading) were applied to simulate the hot and cold food/beverages intake. The Von-Mises Stress (VMS) on the lower margin of the crack surface was measured at 20 points in each model, and the position of the stress concentration on the crack surface was analyzed.

RESULTS

All three restoration types effectively improved stress distribution. The influence of different restorative modalities on the stress distribution at the crack tip exhibited different trends under different loading conditions. Lateral loading and/or hot thermal cycling increased the intensity of VMS, and crown restoration exhibited the highest stress concentration at the crack tip under lateral loading and hot thermal cycling.

CONCLUSIONS

From a mechanical perspective, the outcome of this study suggested that a full crown restoration is not the optimal choice for preventing further crack propagation. Additionally, it is recommended to reduce the consumption of excessively hot foods and beverages daily.

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

The images of the Quantitative Light induced Fluorescent (QLF) device, which provides both natural color images similar to those from intraoral cameras and fluorescent images using 405 nm light in a single shot, were evaluated for the validity and inter examiner reliability in detecting tooth cracks. QLF images of 26 cracked teeth before and after removing crack lines were taken. Two examiners assessed the QLF images before removing the crack line with natural color images, fluorescent images, and combination images showing both images simultaneously, and recorded the crack's location after observing images. The reference standard of the crack's location was established by a trained dentist based on QLF images after removing the crack line. The agreement between examiners and the reference standard of the crack line was calculated by kappa value. Inter examiner agreement of natural color images showed at 0.394, while fluorescent and combination images showed at 0.449 and 0.493. Compared with the reference standard, the combination and fluorescent images showed higher agreement at 0.742 and 0.662, while the natural color images showed the lowest agreement, at 0.164. Determining crack location using only natural colored QLF images is challenging, but fluorescent and combination images improved agreement between examiners and the reference standard.

Managing Cracked Teeth with Root Extension: A Prospective Preliminary Study Using Biodentine™ Material

Purpose

The authors of this study proposed an innovative approach involving the use of Biodentine™ material as an intraorifice barrier in cracked teeth with root extension to promote internal crack sealing, preventing the possibility of microinfiltration and apical crack propagation.

Materials and Methods

The dental records of 11 patients with 12 posterior cracked teeth with root extension were included with a precise protocol performed by a senior endodontist. The treatment protocol included pulp diagnosis, crack identification using a dental operating microscope (DOM), endodontic treatment, placing a Biodentine™ as an intraorifice barrier, and immediate full-coverage restoration. The effectiveness of the treatment was assessed at two intervals, 6 months, and 1-3 years posttreatment, evaluating clinical, radiographic, and tomographic aspects. The treatment was deemed successful if there were no indications of radiolucency, sinus tracts, edema, or periodontal pockets associated with the crack line.

Results

The study observed remarkably positive outcomes during the follow-up period, which spanned from 1 to 3 years. All the cracked teeth (100%) remained asymptomatic, meaning they were free of pain or discomfort. Furthermore, these teeth were in occlusal function. Both radiographic and tomographic assessments revealed the absence of bone loss along the crack line. This outcome signifies that the treatment effectively prevented further deterioration of the surrounding bone.

Conclusions

Integrating advanced biomaterials and conservative restorative techniques has paved the way for innovative approaches in dental care. This protocol suggests a proactive step for managing cracked teeth with root extension. It addresses both biological aspects by sealing internal cracks and mechanical aspects by preventing crack progression, thereby improving these teeth' prognosis and long-term survival.

The treatment outcomes of cracked teeth: A systematic review and meta-analysis

OBJECTIVES

The aim of this review was to analyze the clinical treatment outcomes of cracked teeth (CT) retaining vital dental pulp (CT-VDP) or undergoing root canal treatment (CT-RCT).

SOURCES

A systematic search was conducted in Medline, Embase, PubMed, and Cochrane Library databases.

STUDY SELECTION

Studies evaluating tooth survival rate (TSR), pulp survival rate (PSR), and success rate (SR) with at least a one-year follow-up were included. The risk of bias was evaluated with the Newcastle-Ottawa scale.

DATA

Twenty-seven studies underwent qualitative analysis, 26 of which were included in the meta-analysis. SR of monitoring without restorative treatments was 80 % at three years. TSR of CT-VDP was 92.8-97.8 % at 1‒6 years, PSR of CT-VDP was 85.6‒90.4 % at 1‒3 years, and SR of CT-VDP was 80.6‒89.9 % at 1‒3 years; TSR of CT-RCT was 90.5‒91.1 % at 1‒2 years, and SR of CT-RCT was 83.0‒91.2 % at 1‒4 years. Direct restorations without cuspal coverage for CT-VDP increased the risk ratio (RR) of pulpal complications (RR=3.2, 95 % CI: 1.51-6.82, p = 0.002) and tooth extraction (RR=8.1, 95 % CI: 1.05-62.5, p = 0.045) compared with full-crown restorations. The CT-RCT without full-crown restorations had an 11.3-fold higher risk of tooth extraction than the CT-RCT with full-crown restorations (p < 0.001).

CONCLUSIONS

Monitoring without restorative treatments might be an option for the CT without any symptoms. Direct restorations without cuspal coverage for the CT-VDP could significantly increase the RR of pulpal complications and tooth extraction compared with full-crown restorations. Full-crown restorations are strongly recommended for the CT-RCT.

CLINICAL SIGNIFICANCE

Monitoring without restorative treatments could be a viable option for the CT without any symptoms. Full-crown restorations are strongly recommended for the CT with any symptoms and the CT-RCT.

Do onlays and crowns offer similar outcomes to posterior teeth with mesial-occlusal-distal preparations? A systematic review

OBJECTIVE

Teeth prepared for mesial-occlusal-distal (MOD) restorations have a significant risk of cusp fracture. Crowns and onlays can provide cusp coverage to reinforce posterior teeth at risk. Onlays are often more conservative of tooth structure which may be an advantage for teeth with large MOD preparations. It remains uncertain how onlays and crowns compare for posterior teeth with MOD tooth structure loss. The purpose of this systematic review was to compare the resistance to fracture, success rate, survival rate, and failure rate of teeth with MOD preparations restored with onlays or crowns.

MATERIALS AND METHODS

An electronic search queried Medline (PubMed), Embase (Ovid), Scopus, the Cochrane Library, and grey literature (OpenGrey) from database inception through April 29, 2023.

RESULTS

After eliminating duplicates and irrelevant records, 32 manuscripts were assessed. Only three publications met the criteria for inclusion. Most exclusions were due to poor reporting of restorative design and the amount of tooth structure remaining, or due to combining various restorative designs. Due to the limited sample size and high heterogeneity, no meta-analysis was conducted. One study observed a better outcome for onlays and two observed no difference. All three studies reported the mode of failure for crowns as more catastrophic whereas teeth with onlays could be salvaged.

CONCLUSIONS

Onlays may be an advantageous alternative to crowns for teeth with MOD preparations, but the level of evidence is insufficient to draw meaningful conclusions.

CLINICAL SIGNIFICANCE

Current evidence is insufficient to determine whether onlays or crowns are providing a different outcome when used to restore posterior teeth with MOD tooth structure loss. However, the fracture of teeth with MOD tooth structure loss restored with onlays appears to be less catastrophic than when restored with crowns.

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.

Survivability of endodontically treated cracked tooth: A systematic review

BACKGROUND

Literature evidence describes various treatment protocols that have been employed for the effectiveness in improving survival and addressing associated symptoms of cracked teeth.

OBJECTIVE

This systematic review investigates the survivability of endodontically treated cracked teeth and associated assessments, focusing on various treatment protocols.

METHODS

The PRISMA guidelines were utilised for guiding the article selection framework of this review. A comprehensive search of relevant literature was conducted in May 2023 across various databases, and studies meeting the inclusion criteria were selected. Data extraction, guided by a standardized form, captured crucial details, including study characteristics, treatment protocols, and treatment outcomes, enhancing the consistency and accuracy of information collection. Data extraction and synthesis was done by two reviewers independently. The Newcastle Ottawa tool was used to measure the methodological quality of the study. Six observational studies were eventually included.

RESULTS

Mandibular molars are particularly prone to developing cracks, with research indicating a heightened susceptibility to this dental issue. Studies reveal that endodontically treated cracked teeth boast robust overall survival rates ranging from 75.8% to 100%. The risk of bias assessment, utilizing the Newcastle Ottawa scale, indicated a moderate risk across studies, highlighting the necessity for careful interpretation of findings.

CONCLUSION

Endodontically treated cracked teeth show marked success in survival, with the incorporation of crowns post-endodontic treatment significantly enhancing longevity and resilience.

Biting and thermal sensitivity relief of cracked tooth restored by occlusal veneer: A 12-to 24 months prospective clinical study

OBJECTIVES

To analyze the relief time and risk factors of biting/thermal sensitivity in cracked tooth (CT) restored using occlusal veneer.

METHODS

63 CT were analyzed, and their demographic and clinical data and medical history were collected. Patients were followed-up to examine the relief of thermal/biting sensitivity.

RESULTS

The maxillary first molar was the most prevalent (N = 25, 40%). The number of crack lines on the finish line ranged from 1 to 6 while the number of crack lines through preparation on the finish line from 0 to 4. Pain relief achieved steadily to 52% for thermal and 62% for biting at 1 week to over 90% for each by 3 months and was completely resolved (no pain) for each by 12 months. Painful of lateral percussion was related to a long period of thermal sensitivity (≥1 month) after restoration with occlusal veneer. The number of crack lines through preparation on the finish line >2 was correlated with biting sensitivity (≥1 month) post-treatment.

CONCLUSIONS

Most patients (>90%) became asymptomatic of biting and thermal sensitivity within 3 months of CT restored by occlusal veneer. Lateral percussion and the number of crack lines through preparation on the finish line could be significant factors affecting postoperative symptoms.

CLINICAL SIGNIFICANCE

Occlusal veneer is an ultrathin restoration and had no need for restricting clinical crown height, which could protect and relief the biting/thermal sensitivity of CT without preventive root canal therapy.

Quantifiable design and comparative evaluation of straight-line minimally invasive endodontic cavity based on the anatomical features of the coronal part of root canal

Background/purpose

Minimally invasive endodontics has recently become popular in research. This study aimed to develop a new quantifiable straight-line minimally invasive endodontic cavity (SMIEC) for 3-rooted maxillary first molar based on the anatomical features of the coronal part of root canal.

Materials and methods

Cone-beam computed tomography (CBCT) images of 80 teeth were converted into models in Mimics Research software. Anatomical features of the coronal part of root canal were measured to develop SMIECs with straight-line accesses to root canals in 3-matic Research software. Twenty models were randomly sampled and each was duplicated for 8 simulation groups: non-treated (NT), traditional endodontic cavity (TEC), ninja endodontic cavity (NEC) and 5 SMIECs. Post-simulation models were subjected to finite element analysis to detect von-Mises stresses in ABAQUS software.

Results

Distributions of straight-line accesses to protogenetic root canals had certain manners, hence we developed 5 SMIECs. NEC and SMIECs had less hard tissue loss than TEC and presented different numerical rankings in different structures (P < 0.05). NEC had a less narrow surgery field than SMIECs except SMIEC2/4 (P < 0.05). The peak pericervical stresses of SMIECs were similar, lower than TEC and higher than NEC and NT (P < 0.05). The stress distributions of the 8 groups had certain manners.

Conclusion

Five SMIECs with straight-line accesses to root canals were developed, whose biomechanical properties were worse than NEC but better than TEC. Having appropriate structure preservation and surgery field, SMIEC2/4 was a preferred SMIEC.

Effects on different full-coverage designs and materials of crack propagation in first mandibular molar: an extended finite element method study

Objectives: This study aims to investigate the biomechanical properties of fracture resistance in cracked teeth using five different full-coverage restorations made of three different materials. Materials and Methods: A 3D model of a mandibular first molar was created to design five different full-coverage repair models: crown, crown with composite resin filling inside, occlusal veneer, occlusal veneer with composite resin filling inside and onlay. These repair models were fabricated using three different materials, namely, zirconia, lithium disilicate (LDS), and a hybrid polymer-infiltrated ceramic network material (PIC). In total, 15 repair models were tested using the extended finite element method (XFEM), with an occlusal load of 5000 N applied slowly to the occlusal surface of the restoration. The analysis of stress distribution in the restoration and dentin crack line was conducted to measure and record the crack initial load on the restoration and dentin. Results: The results showed that restorations on the occlusal surface significantly improved crack resistance, with zirconia exhibiting superior fracture resistance among the materials tested. Restorations of crown with composite resin filling inside demonstrated the highest resistance to fracture, while occlusal veneers showed the lowest. MPS concentration was observed at the interface between the restoration and dentin and at the root bifurcation, with the highest values at the top of crack development. Dentin covered by oxidized restorations had the highest displacement, while PIC restorations exhibited the lowest. Pulp analysis revealed selective MPS concentration and strain patterns in models with zirconia restorations and onlay, with pronounced pulp displacement in zirconia restorations and onlay. Enamel analysis indicated larger MPS values and displacements in zirconia restoration models and onlay, with higher strain in onlay. Restoration played a crucial role in protecting the tooth, with crack propagation initial loads in dentin surpassing restorations in experimental groups. Conclusion: This study confirms that full-coverage restorations significantly increased the fracture resistance of cracked teeth, with zirconia restorations significantly protecting the underlying cracked tooth. Elimination of fracture lines in the restoration design can improve fracture resistance in cracked teeth. The findings have implications for dental prosthetic design and clinical practice.

Milled Crown on Post Crack Tooth Syndrome as the Denture Abutment Tooth: A Case Report

This clinical case describes using a milled crown on a cracked tooth as the abutment for a removable partial denture. A 63-year-old male patient diagnosed with lipoma undergoing chemotherapy and radiotherapy presented with symptomatic crack tooth syndrome on tooth 36 and partial edentulism. Conservative treatment using a molar band to extracoronally splint the tooth was conducted to determine the prognosis of the crack line. A lower partial cobalt-chromium denture was constructed by incorporating the milled crown of tooth 36 as the abutment. After six months of follow-up, there were no crack tooth symptoms, and regular review was adopted to monitor the tooth. The construction of a milled crown of a cracked tooth presented good and promising clinical outcomes in preserving tooth vitality and preventing crack propagation in partially dentate dentition for the long term.

Biomechanical perspectives on dentine cracks and fractures: Implications in their clinical management

OBJECTIVES

The present review discussed the biomechanical properties of cracks and fractures in crown and root dentine and attempted to explain why cracked teeth and vertical root fractures are so frequent despite the existence of multiple crack toughening mechanisms in dentine. The implications of this knowledge were used to justify how these defects are managed clinically.

DATA, SOURCES AND STUDY SELECTION

Literature search was conducted on PubMed, Web of Science, and Scopus for a narrative review on fracture mechanics of crown and root dentine as well as the clinical management of cracked teeth and teeth with vertical root fracture.

CONCLUSIONS

Although dentine is tougher and less brittle than enamel, it's facture toughness is considerably lower than most ductile metals. Because the initiation toughness of dentine is very low, cracks initiate from incipient damage under low stress While crack toughening mechanisms exist that enable dentine to resist crack extension, these mechanisms are often inadequate for protecting dentine from crack propagation that ultimately leads to catastrophic failure. Additional factors such as ageing also reduces the resistance of dentine to crack growth. Because dentine cracks are eventually filled with bacteria biofilms upon exposure to oral fluids, they enable rapid bacteria ingress into the dental pulp via open dentinal tubules. To date, treatment options for cracked teeth are limited. While most teeth with vertical root fracture are recommended for extraction, new strategies have been reported that appeared to achieve short-term success in preserving these teeth.

CLINICAL SIGNIFICANCE

Current strategies for the management for dentine cracks and fractures are limited and their long-term effectiveness remain uncertain. Understanding the characteristics, toughening mechanism and weakening factors of tooth cracks is helpful in designing better treatment.

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.

Characteristics of Cracked teeth with Reversible Pulpitis after Orthodontic Banding - a Prospective Cohort Study

INTRODUCTION

Cracked teeth with reversible pulpitis can be managed with orthodontic bands in the interim before definitive restorations. The aim of this study was to determine short-term outcomes of these teeth following orthodontic band placement. The time taken for definitive pulp diagnoses after orthodontic band placement and associated prognostic factors was also analyzed.

METHODS

One hundred and twenty-five patients with a cracked tooth with reversible pulpitis each were recruited. Pre-operative data including patient and tooth factors were collected. Cracked teeth were banded and reviewed until symptoms resolved before referral for coronal coverage. Kaplan-Meier and Cox analyses were performed to analyze pulp survival of these teeth. Prognostic factors were investigated using Pearson's Chi-Square and Student's T-Test.

RESULTS

One hundred and twenty-two cracked teeth were analyzed. One hundred and thirteen (92.6%) teeth had the pulpitis resolved within two months (Median 40.0; IQR 28-61). The median time taken for progression to irreversible pulpitis or pulp necrosis for teeth that required root canal treatment was three months (Median 90.0; IQR 68-110). No prognostic factors were associated with the resolution of pulpal symptoms. However, higher pre-operative triggered pain scores (p<0.05, HR 1.547) and absence of a distal marginal ridge crack (p<0.05, HR 0.638) were correlated with a longer duration before definitive pulp diagnoses.

CONCLUSION

Following orthodontic band placement, a normal pulp diagnosis was achieved in 92.6% of cracked teeth with pre-operative reversible pulpitis. Definitive pulp diagnoses could be determined in approximately two months. Teeth with higher pre-operative triggered pain scores may require a longer review period.

The Restored Premolars Biomechanical Behavior: FEM and Experimental Moiré Analyses

This study applied the finite element method (FEM) and the moiré strip projection method to evaluate the biomechanical behavior of healthy and endodontic-treated premolar teeth. The finite element method and the moiré strip projection method were applied to evaluate the influence of restored materials in association with cervical lesions and were considered as strain estimates for a tooth sample with 21 units, under loads of 25, 50, 75, and 100 N, frontal and oblique applied. The focused cases were: tooth H healthy; tooth A-MOD amalgam; tooth AL-MOD amalgam + lesion; tooth ALR-MOD amalgam + injury restored; tooth R-MOD resin; tooth RL-MOD resin + lesion; tooth RLR-MOD resin + injury restored. The results obtained by FEM simulation can be considered perfectly validated by the results presented by the experimental moiré projection analysis, demonstrating that the FEM numerical analysis can be used to evaluate the biomechanical behavior of healthy and endodontically treated teeth. Developing an alternative protocol to generate FEM three-dimensional models will lead to a ready and inexpensive tool since there is no need for costly equipment for tooth extraction prognosis.