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.

Therapeutic strategy for cracked teeth

The management of cracked teeth represents a difficulty because their diagnosis is complex and there is no consensus concerning their treatment. The present article explains this pathology within enamel and dentin and also focuses on the clinical consequences of crack development in dental tissue. As cracks have both biologic and mechanical implications, a complete review of the literature on the subject has enabled the development of a comprehensive diagnostic approach to identify cracked teeth and optimize their management. The elements of diagnosis are the bite test, transillumination, the pulp sensitivity test, the periodontal test, radiologic examinations, removal of existing restorations, and the use of quantitative light-induced fluorescence. Finally, the management of biologic and mechanical imperatives relating to the treatment of cracked teeth has allowed the proposal of a reliable and reproducible therapeutic strategy based on two pillars: the arrest of bacterial infiltration using immediate dentin sealing, and the limitation of crack propagation using relative cuspal coverage. In this article, the proposed clinical protocol is explained through the use of a decision map and is illustrated by a clinical case example.

A perspective on the diagnosis of cracked tooth: imaging modalities evolve to AI-based analysis

Despite numerous clinical trials and pre-clinical developments, the diagnosis of cracked tooth, especially in the early stages, remains a challenge. Cracked tooth syndrome is often accompanied by dramatic painful responses from occlusion and temperature stimulation, which has become one of the leading causes for tooth loss in adults. Current clinical diagnostical approaches for cracked tooth have been widely investigated based on X-rays, optical light, ultrasound wave, etc. Advances in artificial intelligence (AI) development have unlocked the possibility of detecting the crack in a more intellectual and automotive way. This may lead to the possibility of further enhancement of the diagnostic accuracy for cracked tooth disease. In this review, various medical imaging technologies for diagnosing cracked tooth are overviewed. In particular, the imaging modality, effect and the advantages of each diagnostic technique are discussed. What's more, AI-based crack detection and classification methods, especially the convolutional neural network (CNN)-based algorithms, including image classification (AlexNet), object detection (YOLO, Faster-RCNN), semantic segmentation (U-Net, Segnet) are comprehensively reviewed. Finally, the future perspectives and challenges in the diagnosis of the cracked tooth are lighted.

Cracked Tooth Syndrome: Assessment, Prognosis and Predictable Management Strategies

Cracked tooth syndrome (CTS) is a common presentation in general practice. The diagnosis and management of teeth with CTS may be difficult due to the unknown extent of the crack. This article reviews the aetiology, diagnosis, management and prognosis of teeth with CTS. A thorough examination is required to effectively assess CTS. Intervention should aim to relieve symptoms and brace the remaining tooth structure effectively against further flexion. Restored teeth with CTS have a guarded prognosis due to the risk of further crack propagation, but the chances of survival at 5-years is acceptable (74.1-96.8%).

Biting pain reproduced by the Tooth Slooth: an aid for early diagnosis of cracked tooth

OBJECTIVE

The purpose of this study was to find a reliable method to reproduce biting pain to facilitate an early diagnosis of cracked tooth and to verify the feasibility of the Tooth Slooth in diagnosing a cracked tooth.

METHOD AND MATERIALS

In this study, 46 intact teeth diagnosed as cracked teeth were selected. Patients were asked to bite wet cotton rolls and the Tooth Slooth, and clinical findings were recorded. The difference in the relevance ratio between these two bite test methods was determined.

RESULTS

The relevance ratio of biting pain by the Tooth Slooth and wet cotton rolls was 91.3% and 32.6%, respectively. There was a statistically significant difference between these two bite tests (P < .001).

CONCLUSIONS

Within the limitations of this study, the relevance ratio of biting pain by the Tooth Slooth was significantly higher than that of the wet cotton rolls. The Tooth Slooth was a reliable method to reproduce biting pain and was useful for early diagnosis of cracked teeth.

Biting pain reproduced by the Tooth Slooth: an aid for early diagnosis of cracked tooth

OBJECTIVE

The purpose of this study was to find a reliable method to reproduce biting pain to facilitate an early diagnosis of cracked tooth and to verify the feasibility of the Tooth Slooth in diagnosing a cracked tooth.

METHOD AND MATERIALS

In this study, 46 intact teeth diagnosed as cracked teeth were selected. Patients were asked to bite wet cotton rolls and the Tooth Slooth, and clinical findings were recorded. The difference in the relevance ratio between these two bite test methods was determined.

RESULTS

The relevance ratio of biting pain by the Tooth Slooth and wet cotton rolls was 91.3% and 32.6%, respectively. There was a statistically significant difference between these two bite tests (P < .001).

CONCLUSIONS

Within the limitations of this study, the relevance ratio of biting pain by the Tooth Slooth was significantly higher than that of the wet cotton rolls. The Tooth Slooth was a reliable method to reproduce biting pain and was useful for early diagnosis of cracked teeth.

Cracked tooth syndrome mimicking trigeminal autonomic cephalalgia: A report of four cases

BACKGROUND

This report describes four cases of cracked tooth syndrome secondary to traumatic occlusion that mimicked trigeminal autonomic cephalalgias. All patients were referred by general practitioners to the Orofacial Pain Clinic at Nihon University Dental School for assessment of atypical facial pain.

CLINICAL PRESENTATION

Case 1: A 51-year-old woman presented with severe pain in the maxillary and mandibular left molars. Case 2: A 47-year-old woman presented with sharp, shooting pain in the maxillary left molars, which radiated to the temple and periorbital region. Case 3: A 49-year-old man presented with sharp, shooting, and stabbing pain in the maxillary left molars. Case 4: A 38-year-old man presented with intense facial pain in the left supraorbital and infraorbital areas, which radiated to the temporoparietal and maxillary regions. All cases mimicked trigeminal autonomic cephalalgias, a group of primary headache disorders characterized by unilateral facial pain and ipsilateral cranial autonomic symptoms. Trigeminal autonomic cephalalgias include cluster headache, paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing/short-lasting neuralgiform headache attacks with cranial autonomic features. Pulpal necrosis, when caused by cracked tooth syndrome, can manifest with pain frequencies and durations that are unusual for pulpitis, as was seen in these cases.

CONCLUSION

Although challenging, differentiation of cracked tooth syndrome from trigeminal autonomic cephalalgias is a necessary skill for dentists.

Detection and Analysis of Enamel Cracks by Quantitative Light-induced Fluorescence Technology

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

These results indicate that QLF technology would be a useful clinical tool for diagnosing enamel cracks, especially given that this is a nondestructive method.

Pain Part 4: Odontogenic Pain

Pain is one of the major reasons that lead patients to seek dental care. For the majority of patients, the pain is of odontogenic origin, as a consequence of dental disease. The timely diagnosis and management of dental pain is an essential component of dental care, and this article reminds readers of the common presenting symptoms of simple dental pain, diagnoses and pragmatic management.

CLINICAL RELEVANCE

Pain of odontogenic origin is common, and distressing. However, the pathology is consistent, as are the symptoms, and an understanding of this underpins the careful history-taking that will lead the clinician to the diagnosis.

Diagnosing, managing, and preventing cracked tooth syndrome

Cracked tooth syndrome (CTS) can be a perplexing disorder to diagnose and manage. Many practitioners wonder whether the latest dental materials and adhesives can or should be used when restoring these teeth. The authors reviewed the literature and developed recommendations for how to diagnose and manage CTS and prevent it in susceptible teeth. As the population continues to age and people retain their teeth longer, it is anticipated that patients will present even more frequently with symptoms of CTS.

Localized idiopathic apical root resorption: a report of five cases with emphasis on differential diagnosis

Seeking to describe the clinical and radiologic features of localized idiopathic apical root resorption (LIAR), the authors conducted a dental literature review of idiopathic external root resorption and performed a retrospective study of LIAR among the identified cases retrieved from a private general practice. Cases involved five patients--one female and four males--ranging in age from 15 to 48 years. The authors concluded that LIAR appears to be a distinct but uncommon clinicopathologic condition that is self-limiting, and therefore warrants no definitive treatment. However, the condition, which can present asymptomatically on routine radiographs or is sometimes associated with clinical symptoms, warrants differentiation from periapical replacement resorption as a result of orthodontics or trauma.

Incomplete cusp fractures: early diagnosis and communication with patients using fiber-optic transillumination and intraoral photography

The diagnosis of incomplete cusp fractures has primarily relied on patient symptoms, which sometimes results in late treatment approaches. The transillumination of tooth structure by a fiber-optic light source can be considered an important adjunct tool in the diagnosis of incomplete cusp fractures before they reach their end stages. Furthermore, transilluminated teeth can be documented by intraoral photography, using a two-handed technique by holding a transillumination device and an intraoral camera simultaneously, with the resulting images shared with the patient. This simple, painless, and noninvasive technique can be incorporated easily into daily practice to evaluate high-risk sites, regardless of patient symptoms. This article reviews incomplete cusp fractures, explains how to detect them using transillumination and intraoral photography, and addresses how to discuss the results with patients.

Solving tooth sensitivity

Solving tooth sensitivity requires both you and the patients to be resilient and to understand that if one approach doesn't work, you can try another one that is non-invasive or, at worst, minimally invasive. Much like the clinician who posted the original question, I strongly believe that it is our responsibility to convince patients that jumping to a radical solution could be totally unnecessary--and expensive-- and still might not solve the problem.

The cracked tooth conundrum: terminology, classification, diagnosis, and management

PURPOSE

To provide an overview of the clinical features, diagnosis, classification and management of cracked teeth which may be a diagnostic challenge in clinical practice.

RESULTS

Cracks may initiate from coronal tooth structure or from within the root and affect healthy or root treated teeth. There are many terminologies and classifications in the literature for cracked teeth that can be as confusing as the array of clinical symptoms which are associated with this condition. The term "cracked tooth syndrome" is misleading as there are a range of symptoms that do not form a distinct and reliable pattern. Symptoms will vary with teeth that have healthy pulps, for teeth with inflamed or necrotic pulps, and for teeth that have been root treated. The American Association of Endodontists have classified five specific variations of cracked teeth; craze line, fractured cusp, cracked tooth, split tooth, and vertical root fracture. The importance of differentiating dentin, pulpal and periodontal pain for diagnosis and treatment for these specific entities will be elaborated. A decision flow chart indicating the treatment options available is presented.

Cracked and broken teeth--definitions, differential diagnosis and treatment

Cracked and broken teeth present a diagnostic dilemma to the dentist and the sooner a correct diagnosis is made the greater are the chances to save the tooth. As the location, direction and size of the crack or fracture dictates the choice of treatment, it is important to first define the types of cracks and fractures in the coronal and radicular tooth structure. Cracks and fractures can be classified as follows: 1. craze lines 2. fractured cusps 3. cracked teeth 4. split teeth 5. vertical root fractures. The vertical root fracture has been described recently in two articles in this publication, and therefore will not be discussed here. Diagnosis of a cracked tooth is not always initially obvious. The patient's response to clinical testing is the primary diagnostic tool along with the dental history provided by the patient. Radiographs are secondary in making a diagnosis. Clinical aids for reproducing the patient's symptoms such as occlusal bite devices, observing occlusal wear facets and the application of cold water to one tooth at a time may isolate the offending tooth. In situations where an irreversible pulpitis is diagnosed, endodontic treatment is indicated. In the case of a questionable diagnosis, or one in which a potential reversible pulpitis is made, a provisional restoration can be placed for an unspecified time as a diagnostic aid. If endodontic therapy were indicated, consultation with the patient as to the compromised prognosis and the alternatives to endodontic treatment is essential.

Analysis of 154 cases of teeth with cracks

It is well known that cracked teeth occur most frequently in the mandibular molars with large or poor restorations, in those over 50 years of age. However, with increasing knowledge and experience with cracks of teeth, cracks appear to be found frequently in intact teeth without restorations. The aim of this study is to analyze the cases of tooth cracks in a dental hospital in a year, and to find out the characteristic features of cracks of teeth. For 1 year, each tooth that were identified as a cracked tooth was recorded and analyzed in terms of the classification of cavity and restorative material, the nature of opposing tooth, the location in the arch, the age and gender, and the clinical signs and symptoms, and treatment result. Cracked teeth were observed most frequently in the teeth with no restorations (60.4%) and with class I restorations (29.2%). The most prevalent age was in those over 40 years of age (31.2% in their 40s, 26.6% in their 50s) and the prevalence was similar in men (53.9%) and women (46.1%). Cracked teeth were found most frequently in the maxillary molars (33.8% in first molar, 23.4% in second molar) than in the mandibular molars (20.1% in first molar, 16.2% in second molar). 96.1% of the cracked teeth responded to the bite test, and 81.1% of the cracked teeth were observed in the mesiodistal direction. The prevalence of cracked tooth was highest in the intact teeth with no restoration, in maxillary molars, and in those over 40 years of age. When examining a intact maxillary posterior tooth that is sensitive to a bite and thermal change, crack in the mesiodistal direction need to be considered one of the causes.

Efficient, conservative treatment of symptomatic cracked teeth

Every practice has patients who complain of cold sensitivity and pain on biting while showing no obvious signs of irreversible pulpitis. After loading each cusp and fossa in a symptomatic quadrant and ruling out pulp and periodontal pathology, definitive treatment can be performed to alleviate the patient's symptoms in a consistent, conservative manner using esthetic computer-aided design/computer-aided manufacturing porcelain restorations. Single-appointment definitive restorations can be advantageous for the patient because of the elimination of many steps involved in laboratory fabrication of porcelain or metal restorations.

Identification of Resected Root-End Dentinal Cracks: A Comparative Study of Transillumination and Dyes

The dilemma of diagnosing and possibly treating dentinal cracks continues to present a challenge in endodontics. The purpose of this in vitro study was to compare the effectiveness of transillumination and dyes in identifying root-end dentinal cracks. Fifty maxillary central incisors were decoronated, and the canals were instrumented to an ISO size 50 at the working length. The apical 3 mm of the roots was resected, and cracks were artificially created in the apical dentin. Four independent examiners evaluated the root ends at x8 magnification with a surgical operating microscope using transillumination (group 1), sodium fluorescein dye (group 2), caries detect dye (group 3), methylene blue dye (group 4), and methylene blue plus transillumination (group 5). The examiners' ability to identify root ends correctly with and without cracks was analyzed by comparing the data with the predetermined standard (cracked and noncracked) using logistic regression analysis. All techniques used were shown to be more effective than random chance at diagnosing cracks. The areas under the curve of the different techniques were as follows: transillumination, 0.81 (95% confidence interval [CI], 0.69-0.93); sodium fluorescein, 0.72 (95% CI, 0.58-0.86); caries detector, 0.76 (95% CI, 0.63-0.89); methylene blue, 0.70 (95% CI, 0.55-0.84); and methylene blue plus transillumination, 0.82 (95% CI, 0.70-0.94). Thus, the crack assessment techniques that gave the best discrimination between cracked and noncracked specimens, regardless of rater, was methylene blue plus transillumination. This study emphasizes the usefulness of transillumination along with magnification in detecting dentinal cracks.

Definitive diagnosis of early enamel and dentin cracks based on microscopic evaluation

The diagnoses of cracked teeth and incomplete coronal fracture have historically been symptom based. The dental operating microscope at 16x magnification can fundamentally change a clinician's ability to diagnose such conditions. Clinicians have been observing cracks under extreme magnification for nearly a decade. Patterns have become clear that can lead to appropriate treatment prior to symptoms or to devastation to tooth structure. Conversely, many cracks are not structural and can lead to misdiagnosis and overtreatment. Methodic microscopic examination, an understanding of crack progression, and an appreciation of the types of cracks will guide a doctor to make appropriate decisions. Teeth can have structural cracks in various stages. To date, diagnosis and treatment are very often at end stage of crack development.

CLINICAL SIGNIFICANCE

This article gives new guidelines for recognition, visualization, classification, and treatment of cracked teeth based on the routine use of 16x magnification. The significance of enamel cracks as they relate to dentinal cracks is detailed.

Introduction to Magnification in Endodontics

Dentistry has recently recognized the practicality and benefits of treating damaged and diseased oral tissues under high magnification levels. Initially, enhanced vision was more-or-less restricted to the use of prescription bifocals, awkward magnifying loops, and heavy cumbersome telephoto glasses; the microscope drew little interest and was quickly viewed as another useless and expensive dental gadget. However, owing to the very nature and demands of the therapy, endodontists were quick to accept and adopt this technology, and the manufacturers were quick to adapt and market their surgical microscopes to the endodontic office. Since acceptance leads to progression, we are currently witnessing manufacturers adapting the microscopic and other magnifying lenses to other areas of dentistry. However, choosing and purchasing a microscope involves a great number of issues, including the adequacy of one's present vision, the type of practice conducted, the demands one places on the quality of his or her dentistry, and the amount of time and expense one wishes to devote to becoming competent in using magnification. In addition, one must become familiar with what the different levels of magnification offer, what different depths and widths of field meet their normal practice needs, the amount of space required for the equipment, and whether the investment is cost effective. This article details all of the benefits as well as the difficulties encountered when embarking on a magnification journey.

CLINICAL SIGNIFICANCE

The art of dentistry is based on precision. The human naked eye is capable of distinguishing fine detail, but it is no match for what can be accomplished when an image is sharpened and enlarged. The microscope and other forms of magnification fill that need, especially for accomplishing endodontic procedures.

Diagnosis, therapy, and prevention of the cracked tooth syndrome

Many morphologic, physical, and iatrogenic factors, such as deep grooves, pronounced intraoral temperature fluctuation, poor cavity preparation design, and wrong selection of restorative materials, may predispose posterior teeth to an incomplete fracture. The resulting cracked tooth syndrome is frequently associated with bizarre symptoms that may complicate diagnosis and can persist for many years. Epidemiologic data reveal that splits or fractures are the third most common cause of tooth loss in industrialized countries, primarily affecting maxillary molars and premolars and mandibular molars. This finding indicates that the cracked tooth syndrome is of high clinical importance. Thus, at-risk teeth should be reinforced early, for instance by castings with cusp coverage or by internal splinting with adhesive ceramic restorations.

Diagnosis and treatment planning: cracked tooth

This article discusses the cracked tooth, one of the five major classifications of longitudinal tooth fractures: 1) craze line; 2) cuspal fracture; 3) cracked tooth; 4) split tooth; and 5) vertical root fracture. The term "longitudinal tooth fracture" was first introduced by Rivera (Personal Communication, Iowa City, IA, 1996) and has two meanings. The first implies distance (length), particularly in the vertical (occlusal-cervical) plane, as illustrated by longitudinal lines on a map. The second indicates that these fractures occur over a period of time. Therefore, the term longitudinal tooth fracture applies to fractures that have both a distance and a time component. Thus, fractures are described that are not related to impact trauma (which occurs primarily in incisors), in which the distance (length) component may be similar, but is immediate instead of over a period of time.

The cracked tooth syndrome

The purpose of this article is to review the clinical features, diagnosis and management of the cracked tooth syndrome (CTS). The condition refers to an incomplete fracture of a vital posterior tooth that occasionally extends into the pulp. A lack of awareness of the condition coupled with its varied clinical features can make diagnosis of CTS difficult. Common symptoms include an uncomfortable sensation or pain from a tooth that occurs while chewing hard foods and which ceases when the pressure is withdrawn. The patient is often unable to identify the offending tooth or quadrant involved, and may report a history of numerous dental procedures with unsatisfactory results. Successful diagnosis and management requires an awareness of the existence of CTS and the appropriate diagnostic tests. Management options depend on the nature of the symptoms and extent of the lesion. These options include routine monitoring, occlusal adjustments, placement of a cast restoration and endodontic treatment. A decision flowchart indicating the treatment options available to the dental practitioner is presented.

Diagnosis and treatment of cracked teeth

The incidence of cracked teeth appears to be increasing as we keep our teeth longer and the stresses of daily life result in crack-inducing habits, such as clenching and bruxism. This article deals with the clinical characteristics, diagnosis, treatment, and prognosis of cracked teeth. Clinical cases are presented emphasizing the importance of early detection and a unique treatment approach to enhance the successful management of cracked teeth.

Pulpal injury: pathology, diagnosis and periodontal reactions

Diagnosis of pulpal disease can be difficult due to the lack of diagnostic signs and symptoms available to the practitioner. An understanding of the possible underlying pathological processes, combined with an exact assessment of the pain history, and appropriate clinical tests, should aid the practitioner in determining the nature of pulpal inflammation, and differentiating it from dentine sensitivity and cracked teeth. The responses of the pulp to traumatic injury to the periodontal membrane (PDM) require special consideration, particularly with respect to the assessment of pulp vitality, and the determination of cases requiring pulp extirpation in order to avoid inflammatory root resorption. Although the pulp is relatively isolated from the rest of the dentoalveolar complex by a dentine/cementum barrier, it is important to remember that it can communicate with the PDM through apical and lateral foramina, and areas of damaged cementum. Hence, it is a priority to both preserve the integrity of the cemental layer in cases of traumatic injury and periodontal disease, and to prevent the inflammation and resorption associated with periapical lesions by accurate diagnosis of irreversible pulpitis and pulp necrosis, followed by appropriate endodontic debridement procedures.

The cracked tooth

Fractured molars and premolars are very common. Fractures usually result from cracks that develop and slowly extend until the tooth separates into buccal and lingual fragments. Sometimes, as these cracks expand, the patient exhibits symptoms of what is commonly referred to as "cracked tooth syndrome" (CTS). When CTS occurs, an opportunity exists to diagnose and treat these patients, to relieve their discomfort and prevent sequelae that would require more extensive treatment.

Coping with cracked tooth syndrome

Cracked tooth syndrome typically poses a diagnostic challenge for the dentist. Symptoms include tenderness to biting on certain foods, often poorly localized, and occasional thermal sensitivity. Knowing where to look for this entity, especially in the mandibular molar region, can be especially helpful. Treatment of the tooth depends on the degree of pulpal involvement and the extent of the crack. Cuspal coverage is required of all cracked posterior teeth that are retainable. Root canal therapy is included if symptoms persist or if pulpal pathosis exists at the outset. Cracks extending beyond the osseous crest indicate a poor prognosis. Armed with this knowledge, the dentist can overcome many cracked tooth dilemmas, resulting in satisfaction for both patient and practitioner alike.

Incomplete fractures in intact bilateral maxillary first molars: a case report

A case of incomplete fractures occurring bilaterally in intact maxillary first molars is described. The etiology, diagnosis, and treatment of incomplete tooth fractures are discussed. The clinical results in this case showed that early diagnosis and treatment can prevent further extension of the crack into the pulp and subsequent complete tooth fracture.

Diagnosis and treatment of the cracked tooth

This review paper discusses the recognised factors which predispose to cracked-tooth syndrome. In addition, common presenting symptoms and the various methods to aid clinical diagnosis of this problem are examined. The incidence of the condition is reported and the prognosis of the various forms of fracture, as suggested by clinical presentation, are outlined with reference to the available literature. Benefits and relative demerits of traditional and more modern treatment options are presented and recommendations made for future research.

Hypersensitivity and pain induced by operative procedures and the "cracked tooth" syndrome

Various dental conditions are responsible for tooth hypersensitivity and pain. They include hypersensitive dentin; the "cracked tooth" syndrome; pulp and periapical irritation, inflammation and/or degeneration; barodontalgia (aerodontalgia); and periodontal pathoses, particularly the pulpal-periodontal syndrome. Each operative condition is reviewed with respect to its etiology, symptomatology, and diagnosis. Some treatment recommendations are made to prevent or reduce symptoms.

A 6-year clinical assessment of electronic facial thermography

OBJECTIVE

To report the findings a 6-year clinical application of ET on patients with orofacial pain.

METHODS

ET was conducted (in a blinded manner) using an Agema 870 unit at 0.1 degree C thermal accuracy. A newly devised thermal classification system was applied: 'normal' when zone delta T was from 0.0 to +/-0.25 degree C, "hot' when zone delta T was > +0.35 degree C, 'cold' when zone delta T was < -0.35 degree C, and 'equivocal' when zone delta T was +/-(0.26-0.35) degree C. Study populations consisted of 164 dental patients mainly with diagnostic problems and 164 matched (control) subjects.

RESULTS

Our prospective, matched study determined that subjects with 'hot' thermograms had the clinical diagnoses of sympathetically maintained pain, peripheral nerve mediated pain, TMJ arthropathy, and maxillary sinusitis. Subjects with 'cold' thermograms were found to have the clinical diagnoses of peripheral nerve-mediated pain and sympathetically independent pain. Subjects with 'normal' thermograms were found to have the clinical diagnosis of cracked tooth syndrome, trigeminal neuralgia, pretrigeminal neuralgia, or psychogenic facial pain. The new system of thermal classification resulted in 92% (301 of 328) agreement in classification of pain patients and matched controls.

CONCLUSION

These studies suggest that ET has promise in aiding the formation of a differential diagnosis of orofacial pain and may help in understanding mechanisms of pain as well as directing therapies.

The cracked tooth syndrome: an elusive diagnosis

The authors review the literature and present a case of cracked tooth syndrome. Special emphasis is placed on diagnostic problems associated with this syndrome. The case report demonstrates classic and atypical features of cracked tooth syndrome.

Cracked teeth--treatment rationale and case management: case reports

The treatment rationale for, and successful management of, six teeth with cracks in the form of incomplete vertical fractures are reported. Further crack propagation was prevented by placement of either stainless steel orthodontic bands or aluminum or acrylic resin provisional crowns, and endodontic treatment was subsequently carried out. The teeth were restored with intraradicular amalgam cores and complete veneer crowns. The teeth were reexamined periodically for up to 3.5 years after treatment. During the period of review, all teeth remained asymptomatic.

A report on two patients with vertical root fracture: a dilemma for the periodontist, endodontist, and patient

This paper describes two patients with vertically cracked roots. They illustrate the detailed attention which should be given to the signs, symptoms, and subsequent investigations which may lead to a diagnosis of vertical root fracture, and show the advantages of consultation between the periodontist, the endodontist, and the general dental practitioner.

Chronic focal sclerosing osteomyelitis associated with a cracked tooth. Report of a case

Chronic focal sclerosing osteomyelitis is a periapical lesion that involves reactive osteogenesis evoked by chronic inflammation of the dental pulp. In most cases, this lesion develops in the mandibular molar region in response to a low-grade infection of the pulp that results from a deep carious lesion. A case is presented in which incomplete tooth fracture was the apparent cause of this type of periapical pathosis.