Non-carious dental lesions, such as abrasion, erosion and abfraction, are frequently found in the cervical area of the teeth. The etiologic factors are multiple and frequently the mechanisms which lead to their appearance and progression are complex, therefore an accurate diagnosis is mandatory and often a multidisciplinary collaboration is needed. This implies a thorough anamnesis and detailed clinical examination which includes periodontal examination and occlusion analysis. A proper and complete diagnosis of cervical non-carious lesions is absolutely essential for a correct therapeutic approach, which is conditioned by the identification and removal of etiologic factors, followed by restorative treatment.
Leziunile dentare necarioase, cum ar fi abraziunea, eroziunea şi abfracţia, sunt întâlnite frecvent în regiunea cervicală a dinţilor. Factorii etiologici sunt multipli şi mecanismele care determină apariţia şi progresia acestora sunt deseori complexe, astfel încât un diagnostic de acurateţe al acestor leziuni este obligatoriu, putând necesita o colaborare multidisciplinară. Aceasta implică o anamneză amănunţită şi un examen clinic detaliat, care include examenul parodontal şi analiza ocluzală. Pentru o abordare terapeutică adecvată, un diagnostic corespunzător şi complet al leziunilor cervicale necarioase este absolut esenţial, acesta fiind condiţionat de identificarea şi înlăturarea, în primul rând, a factorilor etiologici, urmate de tratamentul restaurator.
Non-carious cervical lesions represent the loss of cervical tooth structure without an associated carious lesion, being located around the line where enamel covering the crown and the cementum covering the root meet (cement-enamel junction). In this area, the hard dental tissues have less resistance and thickness, with a maximum frequency of these lesions encountered on the vestibular surface, especially at the level of the front teeth and premolars. These are among the most difficult to treat types of lesions that affect dental surfaces, due to the various and often multifactorial etiology that underlies their occurrence, as well as due to the morphological and functional complexity of the involved area. Non-carious dental lesions, such as abrasion, erosion and abfraction, are frequently found in the cervical area of the teeth. In all these types of lesions, the disappearance of hard dental tissues, both enamel and dentine, is caused by mechanical wear or friction (in case of abrasion), acid dissolution (in case of erosion) or by the fragmentation of enamel prisms and dentin loss (in cases of abfraction)(1).
Also, the occlusal stress, especially nonfunctional or excessive occlusal forces, impacts this area, with multiple implications: on one hand, they determine a specific pattern of lesion and, on the other hand, in this case, the therapeutic management requires a complex, global approach regarding the patient’s locoregional conditions and dental education, in order to increase the restoration longevity in the oral cavity and to prevent relapses(2).
This paper reviews the clinical particularities and the importance of a proper diagnosis in order to raise awareness among physicians about the frequency and specific treatment of choice for non-carious cervical lesions. Thus, very often, these cervical lesions are an expression of other general or locoregional condition of the body, like various systemic pathologies, improper diet habits, and every step – whether it is prevention, patient education or restorative treatment – should be based on a rigorous diagnosis.
Diagnosis of non-carious cervical lesions
A proper and complete diagnosis of cervical non-carious lesions is absolutely essential for a correct therapeutic approach, often a multidisciplinary collaboration being mandatory. This implies a detailed clinical examination and the identification and removal of the etiological factors.
I. Anamnesis. The first step is to acknowledge the dental and medical health history of the patient, which is vital since it’s providing valuable information for the dentist prior to starting treatment. This is obtained during a thorough anamnesis. Given that the first sign suggesting the existence of a non-carious cervical lesion is dentine hypersensitivity – thus, a subjective clinical sign –, the patient is first given the opportunity to present all the symptoms he has experienced. If he is not very precise in providing accurate information regarding his medical history, the doctor is obliged to ask him questions about the time of the appearance of the dentine hypersensitivity, the factor that triggered its appearance, the intensity of the pain, its duration and other characteristics that may be useful in the correct detection of the respective lesion. It is essential to draw up a medical report in which the entire dental and medical history of the patient is noted, in order to determine if there is any pathology that could contribute to the occurrence of non-carious cervical lesions.
The patient must be questioned about the general health status, but also about the eating habits or other relevant aspects, such as:
changing the diet in favor of predominantly acidic foods;
the administration of certain drugs for other systemic diseases;
dental hygiene habits;
carrying out the daily activity in an environment that involves exposure to toxic agents that contribute to exogenous biocorrosion;
endogenous biocorrosion, as a consequence of gastroesophageal reflux, bulimia, anorexia, or in patients with alcoholism or drug addiction(3).
Biomechanical occlusal forces can cause under certain conditions specific non-carious cervical lesions called abfraction. For example, interferences that occur during the functions of the dentomaxillary system, parafunctions, dysfunctions of the temporomandibular joint, the need to adapt muscle structures to excessive occlusal contacts (sometimes as a result of iatrogenic dental treatments), all of these producing tensile and compressive forces that cause microscopic cracks among the hydroxyapatite crystals of enamel and dentin.
As such, especially in the case of suspected abfraction lesions, the following set of questions regarding parafunctions and disorders of the temporomandibular joint is essential to be included in the form that the patient fills out. It consists of the following(4):
Do you tend to grind your teeth?
Have you ever had clenched jaws?
Do you tend to bite your tongue, cheeks or lips?
Do you have the habit of gnawing/chewing various objects such as pens, pencils/nails etc.?
Temporomandibular joint dysfunctions
Do you have difficulty opening your mouth?
Is it difficult for you to make lateral movements of the mandible?
Do you feel muscle fatigue during chewing?
Do you have frequent headaches?
Do you often feel pain or tension in your neck?
Do you notice/feel a deviation of the mandible when opening/closing the mouth?
II. Clinical examination includes extraoral and intraoral examination, along with periodontal examination and occlusion analysis. The assessment of the degree of the hard dental tissue loss is essential in order to apply the appropriate restorative treatment, because not all lesions require immediate treatment. By eliminating the etiological factors, the balance in the oral cavity can be restored(5).
The extraoral examination must precede any other additional examination made for the diagnosis of non-carious cervical lesions. It is addressed especially to the masticatory muscles and evaluates the sensitivity upon palpation, the examiner being careful not to apply too much pressure to the investigated muscular structures. To assess whether there is muscle sensitivity or not, he must palpate with a force equal to 1 kgf.
The intraoral examination represents an overall evaluation of the oral cavity to assess the status of the oral tissues and structures, such as dental status, the aspect and quality of dental and prosthetic restorations, salivary glands and identifying non-carious cervical lesions. One of the most important aspects in their diagnosis is the surface of the enamel, dentin and also enamel-cementum junction, which indicates whether the tooth in question presents a cervical lesion of non-carious etiology or a carious process that has stopped in its evolution. Any enamel imperfections should be noted, photographed and added to the patient’s record in order to appreciate the evolution over time of these existing lesions on the tooth surfaces.
A specific and very important diagnostic element of the non-carious cervical hard substance losses is represented by their morphological characteristics. These can lead to conclusions regarding the etiological factors, as well as the mechanism responsible for their appearance and evolution, although we must bear in mind that very often the etiology of this type of lesions can be multifactorial. So, for an accurate and precise diagnosis, they will be analyzed both macroscopically and microscopically: macroscopic appearance, aspects related to shape (geometry), size, lesion’s texture (smooth or rough) and its topographical location in relation to the enamel-cementum junction, while the microscopic aspect focuses on the histological details of the involved dental hard tissues (e.g., dentin composition, with or without the presence of sclerotic dentin). In current practice, only macroscopic aspects can be taken into account in establishing the diagnosis, the microscopic study being dedicated to scientific research(6). Regarding the shape of non-carious cervical lesions, the classical surface contour described is oval, round, and in cross-sectional contour two types of characteristic aspects are described: wedge-shaped (“V” shaped, specific for abfraction lesions) and concave (“U” shaped). The geometric shape of the lesion has a high impact in its progression, while it is known that in “V” shaped lesions, the internal stress from occlusal load is higher than in “U” shaped lesions. Especially in case of abfraction lesions, if the triggering factor is not detected and removed, it can lead in a variable period of time even to the fracture of the respective tooth or to the loss of the dental restoration(7,8). However, there may also be lesions of irregular shape representing a combination between the two types, as an expression of the complex intrinsic and extrinsic mechanisms mentioned previously. Also, we can meet both forms of non-carious cervical lesions in the same tooth.
Some research identified three major types of non-carious cervical lesions: type 1, with a horizontal oval surface contour and a round cross sectional contour (mainly a result of abrasion mechanism), type 2, with a vertical oval surface contour and a round cross sectional contour (appeared to be related to chemical dissolution), and type 3, with a horizontal oval surface contour and a wedge shape cross sectional contour (as a result of occlusal stress)(9).
Considering the importance of classifying the depth of non-carious cervical lesions, which indicates the severity of the dental wear process, several methods have been developed by which it can be calculated. Researchers Smith and Knight developed an evaluation system – the TWI index (Tooth Wear Index) – to quantify this phenomenon by analyzing the extent of all tooth surfaces affected by the various wear mechanisms(10). This index was the first one designed to measure and monitor multifactorial tooth wear. Later, this although reliable method was simplified, so that Bardsley et al. established the following version of TWI, which can also be used for the diagnosis of non-carious cervical lesions (Table 1)(11).
Regarding the location of these lesions, they can involve the enamel-cement junction, being situated at its level or apical to it, on the radicular tooth surface. In relation to free gingival margin, they can appear clinically to be situated supra- or subgingival. This last aspect influences the isolation method, the choice of the necessary instruments, and the restoration approach and materials(12).
Referring to the texture of non-carious cervical lesions, two distinct types were highlighted, directly related to the etiologic mechanisms of biocorrosion or friction. The effects of biocorrosion characterize a lesion with smooth surfaces, with the enamel having the appearance of a honeycomb and the dentin with a wavy appearance. The presence of cracks-like lesions on the enamel and dentin are typical for the mechanical abrasion caused by the tooth brushing, especially by the hardness of the brush filaments and shape of the endings of the filaments or the type of toothpaste (acid toothpaste non-fluoridated)(13).
It is also very important to investigate the buffering capacity, composition, flow rate, pH and viscosity of saliva, knowing their roles in non-carious cervical lesions etiology.
The periodontal examination is always associated when establishing the diagnosis of cervical lesions in order to assess the presence of an associated gingival retraction and is done before the occlusal examination. The correct and rigorous analysis of the occlusion is essential, especially for the treatment of abfraction lesions(14).
A proper and complete diagnosis of non-carious cervical lesions is essential for a correct therapeutic approach and is based primarily on the identification and removal of the etiological factors, in association with detailed clinical examination. The dentist should have in mind that, frequently, these types of hard dental loss are multifactorial, with a complex etiology. For long-term success, the restorative treatment protocol is applied only after removing the general and local factors, as well as the vicious habits that caused the lesions to appear in the first place. n
Acknowledgements: For this article, all the authors have equal contributions.
Conflict of interest: none declared
Financial support: none declared
This work is permanently accessible online free of charge and published under the CC-BY
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