Correlation between symptoms and external characteristics of cracked teeth: Findings from The National Dental Practice-Based Research Network

Effect of different restorative design and materials on stress distribution in cracked teeth: a finite element analysis study

OBJECTIVES

To compare the stress distribution and crack propagation in cracked mandibular first molar restored with onlay, overlay, and two types of occlusal veneers using two different CAD/CAM materials by Finite Element Analysis (FEA).

MATERIALS AND METHODS

A mandibular first molar was digitized using a micro CT scanning system in 2023. Three-dimensional dynamic scan data were transformed, and a 3D model of a cracked tooth was generated. Finite element models of four different models (onlay, overlay, and two types of occlusal veneer restored teeth) were designed. Two different CAD/CAM materials, including Lava Ultimate (LU) and IPS e.max CAD (EMX), were specified for both models. Each model was subjected to three different force loads on the occlusal surfaces. Stress distribution patterns and the maximum von Mises (VM) stresses were calculated and compared.

RESULTS

Compared to the base model, all restorations showed that high-stress concentration moved from the lower margin of the crack area towards the top of the crack area. The EMX-restored onlay, overlay, and occlusal veneer 2 had the lower stress in the cracked area and the lower average von Mises stress levels at the lower margin along the cracked line, especially under the 225N lateral force (P < 0.05). The occlusal veneer 1 filled with resin had a poorer stress distribution and higher stress concentration of stress at the remaining crack than the occlusal veneer 2 without resin filled inside.

CONCLUSIONS

The EMX restorations with onlay, overlay, and occlusal veneer 2 showed lower stress concentration at the lower margin of crack surface compared to the LU-restored models. The occlusal veneer with internal resin filler exhibited higher stress on the end of the lower margin of the crack surface.

CLINICAL RELEVANCE

Our results suggest that onlay, overlay ceramic restorations and occlusal veneer (without resin filling inside) may be a favorable method to prevent further crack propagation.

TRIAL REGISTRATION

A protocol was specified and registered with the Chinese Clinical Trial Registry (ChiCTR) on 2022-04-12 (registration number: ChiCTR2200058630).

Method of understanding for investigation of crack propagation trajectory and fracture aspects in dental cracks on view of fracture mechanics theories

Current research introduces understanding of dental-cracks mechanistic with fundamental fracture behavior in natural-teeth and orthodontics including mode I crack under both tension and compression, mode II crack under both clockwise-shear and anticlockwise-shear and mixed-mode cracks under both compression-shear and tension-shear. It depends on experimental models of transparent-Plexiglas including pre-cracks of different orientations angle (b) based on fundamental theoretical fracture analysis with comparison. Problem-concept, cracking aspects of fracture-initiation, propagation-direction, fracture-increment length, critical external-load and fracture path are predicted experimentally and theoretically using directional fracture approach and directional strain-energy density theory. Tests are carried out for (36) samples for compression and tension in LEFM. Friction-resistance between crack-surfaces is considered with derivation of equations and charts. Negative stress-intensity factor (-KI) is developed for solving complicated problems of cracks under occlusal compression loads. The occlusal loads are compression and shear producing lateral tensile mixed mode cracks. The critical propagation angle (qc), critical propagation load (sc) and critical propagation envelope of stress intensity factors (KI-KII) are developed with respect to crack orientation angle (b) with comparisons. They are necessary to predict the fracture propagation early before teeth-failure. It helps for prevention and control of dental-cracks, correct-restoration, prosthodontics, orthodontics, and development of new dental-materials and technologies.

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.

A narrative review of cracks in teeth: Aetiology, microstructure and diagnostic challenges

OBJECTIVES

To summarize the available evidence of crack formation in teeth and to discuss the limitations of the current clinical diagnostic modalities for crack detection in teeth.

BACKGROUND

Cracks are a common clinical finding in teeth and yet clinicians still struggle to identify the full extent and orientation of cracks for their appropriate timely management. The biomechanics of crack development can be due to multiple factors and can differ from an unrestored tooth to a restored or endodontically treated tooth.

DATA & SOURCES

This narrative review has been designed following the guidelines published by Green et al. 2006 [1] Published literature in the English language that addresses the objectives of this review up to July 2022 was sourced from online databases and reference lists. The relevance of the papers was assessed and discussed by two reviewers. A total of 101 publications were included in this narrative review.

CONCLUSIONS

The initiation and development of cracks in teeth are likely linked to an interplay between the masticatory forces and fracture resistance of the remaining tooth structure. From the identified literature, the quality and quantity of remaining tooth structure in a restored or endodontically-treated tooth affects the biomechanics of crack development compared to an unrestored tooth. The extent, orientation, and size of the cracks do affect a clinician's ability to detect cracks in teeth. There is still a need to develop reliable diagnostic tools that will accurately identify cracks in teeth beneath restorations to enable effective monitoring of their propagation and provide appropriate interventions.

CLINICAL SIGNIFICANCE

The development and propagation of cracks in an unrestored tooth differ greatly from a restored and endodontically treated tooth; mainly linked to the quantity and quality of the remaining tooth structure and the forces acting on them. Identifying the extent of cracks in teeth remains challenging for early clinical intervention.

Effects of Charcoal Toothpaste on the Surface Roughness, Color Stability, and Marginal Staining of Resin Composites

OBJECTIVE

This study was designed to evaluate the effects of charcoal toothpaste on the surface roughness, color stability, and marginal staining of resin composite restorations.

METHODS

A total of 100 bovine incisors was collected. The crowns were sectioned and randomly divided into 10 groups (n=10) according to two study factors: toothpaste groups and nanoparticle resin composite groups. Five toothpastes-Bianco Pro Clinical (Bianco Oral Care, Uberlândia, MG, Brazil) - Control group; Bianco Carbon (Bianco Oral Care); NAT, Natural Suavetex Carvão Ativado (Suavetex, Uberlândia, MG, Brazil); Nano Action Black Be Emotion (Polishop, Jundiaí, SP, Brazil); and BIW, Black is White (Curaprox, Curaden AG, Kriens, Switzerland)-and two resin composites-Z350XT, Filtek Z350XT (3M Oral Care) and Vittra, Vittra APS (FGM, Joinville, SC, Brazil)-were used. Circular cavities with a diameter of 4 mm and a depth of 1 mm were prepared on the buccal face of the tooth crowns and restored with resin composites. The specimens were subjected to three months of simulated toothbrushing. The surface roughness (right angle [Ra], in micrometers [μm]) of the resin composites was measured before and after toothbrushing in five areas per specimen. The resin composite color and luminosity changes (ΔE and ΔL, respectively) were measured using reflectance spectroscopy (Vita EasyShade). Macro photographs were taken before and after toothbrushing to qualitatively analyze the marginal staining (MSt) of the resin composite restorations. Scanning electron microscopy (SEM) was performed before and after the simulated toothbrushing. Ra data were analyzed using two-way analysis of variance with repeated measures and the Tukey HSD test; MSt was analyzed using Kruskal-Wallis and Dunn tests (α=0.05), and the resin composite color change was analyzed using the clinically unacceptable level of ΔE > 3.3.

RESULTS

Simulated brushing increased Ra irrespective of the resin composite or toothpaste used. No significant differences were found in Ra between the control group and all groups on which the charcoal toothpastes were tested. A clinically unacceptable level of resin composite color change (ΔE>3.3) was found after the use of most charcoal toothpastes. Use of Bianco Carbon resulted in marginal staining similar to that of the control group and was lower than that of the other charcoal toothpastes. Vittra brushed with black toothpaste showed the highest marginal staining.

CONCLUSION

Use of charcoal toothpaste resulted in Ra values of resin composites similar to those found with conventional toothpastes. Charcoal toothpaste generally resulted in clinical resin composite color changes (ΔE). All charcoal toothpastes, except Bianco Carbon, caused marginal staining of the resin composite restorations.

Onset and resolution of pain among treated and untreated posterior teeth with a visible crack: Three-year findings from the national dental practice-based research network

OBJECTIVE

Cracked teeth may be associated with pain, especially biting pain, and to a lesser degree cold and spontaneous pain.  Described are how commonly these pains remain constant, develop, or resolve over time, none of which have been well-described, especially among untreated cracked teeth.

METHODS

Cracked teeth from the Cracked Tooth Registry (CTR) study were followed for 3 years.  Assessments of cold, biting, and spontaneous pain and treatments performed were completed at enrollment (Y0) and at each annual recall visit.

RESULTS

209 practitioners enrolled 2,858 patients, each with a visible crack on a posterior tooth; 2601 (91%) patients attended at least one recall visit. Overall, 960 (37%) were treated, primarily with crowns. Among both treated and untreated cracked teeth with biting pain or spontaneous pain at Y0, the vast majority (92-99%) had their pain resolved by the time of a recall visit and 85-93% remained pain-free after initial resolution. The observations for cold pain were similar: 68% (untreated) and 78% (treated) became free of cold pain at some point during follow-up, and 84% of these stayed free of cold pain after initial resolution. Few teeth developed biting or spontaneous pain (4-8%) and 44-67% of these had pain resolution during the follow-up period.

CONCLUSION

In this study, treatment resolved a preponderance of pain associated with a cracked tooth.  Pain was also resolved for most untreated cracked teeth, especially biting pain, and to a lesser degree spontaneous and cold pain, although not to the same degree as with the treated cracked teeth.

Apical periodontitis after intense bruxism

BACKGROUND

Bruxism is known to cause masticatory muscle pain, temporomandibular joint pain, headaches, mechanical tooth wear, prosthodontic complications and cracked teeth. Less known to the practitioner, and described only experimentally in literature, is that bruxism can also damage the pulp. To our knowledge, this is the first known clinical case of a patient developing apical periodontitis due to bruxism.

CASE PRESENTATION

This article presents the case and successful treatment of a 28-year-old healthy male patient with apical periodontitis on teeth 36 and 46 requiring root canal treatment after an intense phase of bruxism. Due to an unclear diagnosis, treatment had been delayed.

CONCLUSIONS

Incomprehensible tooth pain can be the result of bruxism. Practitioners need to be informed that intense bruxism can possibly lead to apical periodontitis. It is important, therefore, that a thorough anamnesis is collected and taken into account during diagnostics.

Outcomes of treatment and monitoring of posterior teeth with cracks: three-year results from the National Dental Practice-Based Research Network

OBJECTIVES

To describe treatment and monitoring outcomes of posterior teeth with cracks at baseline followed in the National Dental Practice-Based Research Network for up to three years.

MATERIALS AND METHODS

Two hundred and nine dentists enrolled a convenience sample of 2,858 patients, each with a posterior tooth with at least one visible crack and followed them for three years. Characteristics at the patient, tooth, and crack level were recorded at baseline and at annual recall visits. Data on all teeth referred for extraction were reviewed. Data on all other teeth, treated or monitored, seen at one or more recall visits were reviewed for evidence of failure (subsequent extraction, endodontics, or recommendation for a re-treatment).

RESULTS

The survival rate for teeth with cracks at baseline exceeded 98% (only 37 extractions), and the failure rate for teeth that were treated restoratively was only 14%. Also, only about 14% of teeth recommended at baseline for monitoring were later recommended to be treated, and about 6.5% of teeth recommended for monitoring at baseline were later treated without a specific recommendation. Thus, about 80% of teeth recommended at baseline for monitoring continued with a monitoring recommendation throughout the entire three years of the study. Treatment failures were associated with intracoronal restorations (vs. full or partial coverage) and male patients.

CONCLUSIONS

In this large 3-year practice-based study conducted across the USA, the survival rate of posterior teeth with a visible crack exceeded 85%. Clinical relevance Dentists can effectively evaluate patient-, tooth-, and crack-level characteristics to determine which teeth with cracks warrant treatment and which only warrant monitoring.

Oral Functional Behaviors and Tooth Factors Associated with Cracked Teeth in Asymptomatic Patients

INTRODUCTION

A cracked tooth may occur due to excessive applied force or tooth weakness. However, there is scant information concerning the cracked tooth risk factors. This study aimed to explore the oral functional behaviors and tooth factors associated with posterior cracked teeth.

METHODS

Fifty-six patients underwent their oral functional behavior assessment via a questionnaire. The intraoral parameters at the patient level (remaining teeth, occluding tooth pairs, overbite, overjet, and occlusal guidance type) and tooth level (remaining marginal ridge number, restored surface number, restorative materials, and cuspal inclination) were examined. The posterior teeth were stained with methylene blue dye and inspected for cracks using a microscope. The correlations between each patient-level parameter and the cracked tooth number/subject were determined using linear regression analysis. The cracked teeth were matched with their contralateral noncracked teeth, and binary regression analysis was used to analyze the association between tooth-level parameters and a cracked tooth. Multivariate regression analysis was performed if more than 1 parameter had a P value ≤.1.

RESULTS

One hundred thirty-five cracked teeth were found. Eating hard food was significantly related to the cracked tooth number (P < .05). In molars, the occlusal surface restoration and cuspal inclination were significantly related to a cracked tooth, except the mesiobuccal cusp. In the multivariate analysis, the distolingual cusp inclination significantly predicted a cracked tooth (P < .05). In premolars, the lingual cusp inclination was associated with a cracked tooth (P < .05).

CONCLUSIONS

Eating hard food, occlusal surface restoration, and steep cuspal inclination were associated with posterior cracked teeth.

Survival rate after endodontic treatment in general dentistry for cracked teeth with different coronal restorations

OBJECTIVE

The aim of this study was to analyse the survival rate of cracked teeth after endodontic treatment. The secondary aim was to compare the survival rate of cracked teeth restored with composite filling/crown and those restored with a full crown.

MATERIALS AND METHODS

The study was conducted retrospectively from three general dental clinics in Stockholm, which are all part of the national dental service organisation. Two-hundred patients with teeth receiving endodontic treatment due to symptomatic cracks were included. The patient data range from year 2001 to 2016.

RESULTS

The mean age of the patients was 48 years (range 29-69). Fifty-five per cent had cracks located above the pulpal cavity, 11% within the pulpal cavity and 3% located in the root canal. The cracks were located most commonly on the proximal surfaces. The survival rate for teeth with cracks was 68% and 54% after 5 and 10 years, respectively. The survival rate was significantly higher (97%) for cracked teeth receiving a full crown after endodontic treatment compared to teeth restored with either a composite filling or composite crown.

CONCLUSION

The overall survival rate for cracked teeth was 68% after 5 years, while it was significantly higher for cracked teeth restored with a full crown. The results suggest within the limitations of this study that cracked teeth should be restored with a full crown after endodontic treatment.

Cracked teeth: Distribution and survival at 6 months, 1 year and 2 years after treatment

BACKGROUND/PURPOSE

The unpredictable condition of cracked teeth warrants further investigation and clinical experiences. The purpose of this study was to collect and record data on demographics, clinical characteristics, different treatment modalities and survival of cracked teeth at 6-month, 1-year and 2-year recalls.

METHODS

77 cracked teeth from 65 patients were included. Data on demographics, clinical parameters, treatment modalities and recall were collected. Binomial, multinomial and chi square tests were used for statistical analysis.

RESULTS

Most cracked teeth occurred in patients greater than 40 years old (p < 0.01). Cracked teeth themselves were most often molars (79.22%; p < 0.01), a non-terminal tooth in the arch (62.34%; p < 0.05) and nonendodontically-treated teeth (94.81%; p < 0.01). Cracked teeth exhibited pain to percussion (63.64%, p < 0.05) or biting (74.03%; p < 0.01), and no or only positive mobility (76.62%; p < 0.01). Cracks were most often oriented in the mesiodistal direction (68.83%; p < 0.01). Higher survival rates were noted in cracked teeth lacking pre-operative pain to palpation or spontaneous pain, and with no or only positive mobility at 6-month and 1-year recalls. In vital cracked teeth, higher survival rates were noted in teeth lacking pre-operative pain to palpation and with no or only positive mobility at 2-year recalls.

CONCLUSION

The absence of pre-operative palpation discomfort, spontaneous pain and minimal mobility, as well as the presence of pulp vitality were associated with higher survival rates of cracked teeth at all recall times. Results are useful for diagnosis and outcomes-based treatment planning of cracked teeth.

A Retrospective Evaluation of the Prevalence of Cracked Teeth Among an Adult Population in Nevada

OBJECTIVE

To identify the distribution and characteristics of cracked teeth in a Southern Nevada population attending the dental clinics of the School of Dental Medicine, University of Nevada, Las Vegas (SDM, UNLV).

METHODS

A retrospective keyword search of the clinical notes of SDM, UNLV patient charts in AxiUm™ was performed using the search terms 'crack' and 'fracture' to discern the number of patients that had clinically identifiable teeth with cracks, and which teeth (if any) had documented symptoms consistent with the cracks. The inclusion criteria for the record search were individuals ≥18 years old, seen at the dental clinic between 2010 and 2018. Demographic data were analyzed using a Chi-square test against the demographics for Clark County's population.

RESULTS

893 patients presented with cracked teeth, of which 41% had documented symptoms. Patients in the 45-54 age range had the highest number of teeth with cracks (P<0.001). Males comprised 49% of the cases. Caucasians (58.9%) and African Americans (21.1%) represented a majority of the population with cracked teeth (P<0.0001). 1st and 2nd molars had the highest predilection for fractures (59.8%).

CONCLUSION

Mandibular and maxillary first and second molars were amongst the highest teeth affected with cracks.

Factors Related to the Outcomes of Cracked Teeth after Endodontic Treatment

INTRODUCTION

Cracked teeth are a common clinical finding; however, their presence renders diagnosis and prognosis unreliable. The purpose of this research was to assess the correlations of multiple factors on the prognosis of cracked teeth that had undergone endodontic treatment.

METHODS

A total of 3680 patients who received endodontic treatment by an advanced postdoctoral education program in endodontics with follow-up records of at least 1 year were assessed. From this sample, 62 patients met the inclusion criteria and were included in the final analysis. The factors being evaluated included demographics, clinical symptoms and signs, radiographic findings, and restoration type. Statistical analysis was then completed using the chi-square and Fisher exact tests.

RESULTS

The mean follow-up period was 23.3 months, with an overall tooth success rate of 75.8%. The success rates differed significantly when the patient had an existing preoperative periapical lesion, lacked a proper permanent restoration on the treated tooth, or had a post placed after root canal treatment. Data analysis showed that restoring the tooth after endodontic treatment was the single most important factor for prognosis. In fact, the endodontically treated teeth with definitive full-coverage restorations had a 2-year success rate of 93.6%.

CONCLUSION

Full-coverage restorations should be considered an important part of the treatment plan for cracked teeth treated endodontically.

Symptom changes and crack progression in untreated cracked teeth: One-year findings from the National Dental Practice-Based Research Network

OBJECTIVES

The study objective was to: (1) quantify symptom (pain) and crack changes during one year of follow-up, among teeth that had at least one visible crack at baseline but which did not receive treatment for those cracks; (2) identify any patient traits/behaviors and external tooth/crack characteristics correlated with these changes.

METHODS

In this observational study, 209 National Dental Practice-Based Research Network dentists enrolled a convenience sample of 2858 subjects, each with a single, vital posterior tooth with at least one observed external crack; 1850 teeth remained untreated after one year of follow-up and were the cohort for analyses. Data were collected at the patient-, tooth-, and crack-level at baseline, one-year follow up (Y1), and interim visits. Associations between changes in symptoms and cracks were identified, as were changes in symptoms associated with baseline treatment recommendations.

RESULTS

Changes in pain symptoms were observed in 32% of patients; decreases were twice as common as increases (23% vs. 10%). More changes were observed in cold pain than in biting pain and spontaneous pain combined; 2% had increases in biting pain and 2% in spontaneous pain. Only 6% had an increase in the number of cracks. Changes in pain symptoms were not associated with an increase in the number of cracks, but were associated with baseline treatment recommendations. Specifically, pain symptom changes (especially decreases) were more common when the tooth was recommended for treatment at baseline.

CONCLUSIONS

Cracked teeth that have not received treatment one year after baseline do not show meaningful progression as measured by increased symptoms or number of cracks during follow-up.

CLINICAL SIGNIFICANCE

Untreated cracked teeth, most of which were recommended for monitoring at baseline and some of which were recommended for treatment but did not receive treatment, remained relatively stable for one year with little progression of cracks or symptoms.

Recommended treatment of cracked teeth: Results from the National Dental Practice-Based Research Network

STATEMENT OF PROBLEM

Despite the high prevalence of posterior cracked teeth, questions remain regarding the best course of action for managing these teeth.

PURPOSE

The purpose of this clinical study was to identify and quantify the characteristics of visible cracks in posterior teeth and their association with treatment recommendations among patients in the National Dental Practice-Based Research Network.

MATERIAL AND METHODS

Network dentists enrolled patients with a single, vital posterior tooth with at least 1 observable external crack. Data were collected at the patient, tooth, and crack levels, including the presence and type of pain and treatment recommendations for subject teeth. Frequencies according to treatment recommendation were obtained, and odds ratios (ORs) comparing recommendations for the tooth to be restored versus monitored were calculated. Stepwise regressions were performed using generalized models to adjust for clustering; characteristics with P<.05 were retained.

RESULTS

A total of 209 dentists enrolled 2858 patients with a posterior tooth with at least 1 crack. Mean ±standard deviation patient age was 54 ±12 years; 1813 (63%) were female, 2394 (85%) were non-Hispanic white, 2213 (77%) had some dental insurance, and 2432 (86%) had some college education. Overall, 1297 (46%) teeth caused 1 or more of the following types of pain: 1055 sensitivity to cold, 459 biting, and 367 spontaneous. A total of 1040 teeth were recommended for 1 or more treatments: restoration (n=1018; 98%), endodontics (n=29; 3%), endodontic treatment and restoration (n=20; 2%), extraction (n=2; 0.2%), and noninvasive treatment, for example, occlusal device, desensitizing (n=11; 1%). The presence of caries (OR=67.3), biting pain (OR=7.3), and evidence of a crack on radiographs (OR=5.0) were associated with over 5-fold odds of recommending restoration. Spontaneous pain was associated with nearly 3-fold odds; pain to cold, having dental insurance, a crack that was detectable with an explorer or blocked transilluminated light, or connected with a restoration were each weakly associated with increased odds of recommending a restoration (OR<2.0).

CONCLUSIONS

Approximately one-third of cracked teeth were recommended for restoration. The presence of caries, biting pain, and evidence of a crack on a radiograph were strong predictors of recommending a restoration, although the evidence of a crack on a radiograph only accounted for a 3% absolute difference (4% recommended treatment versus 1% recommended monitoring).

Observable characteristics coincident with internal cracks in teeth: Findings from The National Dental Practice-Based Research Network

BACKGROUND

This study determined if there are observable patient-, tooth- and crack-level characteristics markedly associated with whether a tooth with an external crack also has an internal crack.

METHODS

Two hundred nine dentists in The National Dental Practice-Based Research Network enrolled 2,858 adults with a vital permanent posterior tooth having at least 1 observed external crack. Presence and characteristics of internal cracks were recorded for 435 cracked teeth that were treated. Generalized estimating equations were used to identify significant (P < .05) independent odds ratios associated with the tooth having internal cracks.

RESULTS

Overall, 389 teeth (89%) had at least 1 internal crack, with 46% of these teeth having 2 or more internal cracks. Sixty-nine percent of treated cracked teeth were associated with 1 or more types of pain assessed before treatment; 53% were associated with cold testing, 37% with bite testing, and 26% with spontaneous pain. In the final model, biting pain, having an external crack that connected with a restoration, or an external crack that extended onto the root was each associated with more than a 2-fold increased odds of having an internal crack.

CONCLUSIONS

Essentially 9 of 10 teeth that had at least 1 external crack also had at least 1 internal crack.

PRACTICAL IMPLICATIONS

The external cracks that a dental practitioner should be most concerned about, because they are most likely to be associated with internal cracks in the tooth, are those in which the patient experiences biting pain, is connected with a restoration of some type, or extends onto the root.

Associations of types of pain with crack-level, tooth-level and patient-level characteristics in posterior teeth with visible cracks: Findings from the National Dental Practice-Based Research Network

OBJECTIVES

The objective of this study was to determine which patient traits, behaviors, external tooth and/or crack characteristics correlate with the types of symptoms that teeth with visible cracks exhibit, namely pain on biting, pain due to cold stimuli, or spontaneous pain.

METHODS

Dentists in the National Dental Practice-Based Research Network enrolled a convenience sample of subjects each of whom had a single, vital posterior tooth with at least one observable external crack (cracked teeth); 2858 cracked teeth from 209 practitioners were enrolled. Data were collected at the patient-, tooth-, and crack-level. Generalized estimating equations were used to obtain significant (p < .05) independent odds ratios (OR) associated with teeth that were painful for 10 outcomes based on types of pain and combinations thereof.

RESULTS

Overall, 45% of cracked teeth had one or more symptoms. Pain to cold was the most common symptom, which occurred in 37% of cracked teeth. Pain on biting (16%) and spontaneous pain (11%) were less common. Sixty-five percent of symptomatic cracked teeth had only one type of symptom, of these 78% were painful only to cold. No patient-, tooth- or crack-level characteristic was significantly associated with pain to cold alone. Positive associations for various combinations of pain symptoms were present with cracks that: (1) were on molars; (2) were in occlusion; (3) had a wear facet through enamel; (4) had caries; (5) were evident on a radiograph; (6) ran in more than one direction; (7) blocked transilluminated light; (8) connected with another crack; (9) extended onto the root; (10) extended in more than one direction; or (11) were on the distal surface. Persons who were <65 yo or who clench, grind, or press their teeth together also were more likely to have pain symptoms. Pain was less likely in teeth with stained cracks or exposed roots, or in non-Hispanic whites.

CONCLUSIONS

Although pain to cold was the most commonly noted pain associated with symptomatic cracked teeth, no patient-, tooth- or crack-level characteristic was significantly associated with pain to cold alone. Characteristics were only associated with pain on biting and/or spontaneous pain with or without pain to cold.

CLINICAL SIGNIFICANCE

Although often considered the most reliable diagnosis for a cracked tooth, pain on biting is not the most common symptom of a tooth with a visible crack, but rather pain to cold.

Quantitative percussion diagnostics as an indicator of the level of the structural pathology of teeth: Retrospective follow-up investigation of high-risk sites that remained pathological after restorative treatment

STATEMENT OF PROBLEM

Structural damage may remain even after a tooth is restored. Conventional diagnostic aids do not quantify the severity of structural damage or allow the monitoring of structural changes after restoration.

PURPOSE

The purpose of this retrospective clinical study was to provide an in-depth analysis of 9 high-risk sites after restoration. The analysis followed structural defects found upon disassembly, restorative materials used, therapeutic procedures provided, current longevity, and long-term quantitative percussion diagnostics (QPD) to monitor results. The hypothesis was that QPD can be used to quantify positive and negative changes in structural stability.

MATERIAL AND METHODS

Sixty sites requiring restoration were part of an institutional review board-approved clinical study. Each participant was examined comprehensively, including QPD testing, at each follow-up. Long-term changes in normal fit error (NFE) values after restoration were evaluated according to a pathology rating system established in an earlier publication. Nine highly compromised sites were chosen for further analysis and monitored for an additional 6 years.

RESULTS

Of the 9 high-risk sites (NFE>0.04), 7 sites improved and 2 sites deteriorated. Potential causes for each trend were documented.

CONCLUSIONS

The data support the hypothesis that QPD can be used to monitor changes in structural stability after restoration. Knowledge of changes in advance of any symptoms allows further preventive or therapeutic intervention before serious structural damage can occur. Follow-up QPD indications of site improvement can also assure the clinician of the desired structural outcome.