Non-carious cervical lesions on an incisor

Non-carious cervical lesions (NCCLs) are a group of lesions that are characterised by a loss of hard dental tissue at the cementoenamel junction (CEJ) region at the neck of the tooth, without the action of

microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

s or inflammatory processes. These lesions vary in shape from regular depressions that look like a dome or a cup, to deep wedge-shaped defects with the apex pointing inwards. NCCLs can occur either above or below the level of the gum, at any of the surfaces of the teeth.
$Abfraction$

Aetiology

NCCL is a complex multifactorial condition and it is believed that multiple factors contribute to the formation of such lesions. Traditionally, the believed aetiological causes for NCCL have been

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

and abrasion. However, in the past few decades,

abfraction Abfraction is a theoretical concept explaining a loss of tooth structure not caused by tooth decay (non-carious cervical lesions). It is suggested that these lesions are caused by forces placed on the teeth during biting, eating, chewing and grin ...

has been implicated as a possible contributing factor of NCCLs as well. Bartlett and Shah propose that NCCLs arise from a combination of all three factors:

, abrasion and possibly

as well.Bartlett D., Shah P. A Critical Review of Non-carious Cervical (Wear) Lesions and the Role of Abfraction, Erosion, and Abrasion. Journal of Dental Research. 2006;85(4):306–12. While the role of

and abrasion in NCCLs is well proven, more research still needs to be done to prove the

theory.

Erosion and Abrasion

Erosion is the “non-

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

l loss of tooth substance due to chemical agents”Ireland R. Dictionary of Dentistry. Oxford: Oxford University Press; 2010. with the most common form being

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

s. There are two form of acids that contribute to erosive tooth wear: intrinsic and extrinsic. Intrinsic acids are from

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...

and regurgitation. Individuals suffering from medical conditions associated with

and regurgitation such as

gastroesophageal reflux Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases where stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/ ...

(GERD),

bulimia nervosa Bulimia nervosa, also known as simply bulimia, is an eating disorder characterized by binge eating followed by purging or fasting, and excessive concern with body shape and weight. The aim of this activity is to expel the body of calories eate ...

chronic alcoholism Alcoholism is, broadly, any drinking of alcohol that results in significant mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognized diagnostic entity. Predomina ...

, and hyperemesis gravidum in pregnancy are hence at higher risk of developing erosive NCCLs. On the other hand, extrinsic acids include dietary

s in soft drinks, sports energy drinks, fruit juices, chewable vitamin C tablets, sweet-sour candies, herbal teas, dry wine and vinegar-containing foods. Abrasion is defined as the “non-bacterial loss of tooth tissue due to

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of t ...

al wear by extrinsic agents”. It is well documented in literature that

and abrasion act together

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...

to create NCCLs.Rees JS. The biomechanics of abfraction. Proceedings of the Institution of Mechanical Engineers Part H, Journal of engineering in medicine. 2006;220(1):69–80. Abrasion is believed to arise from toothbrushing, due to the tooth surface coming into contact with “hard abrasive particles in the toothpaste”. Acids within the mouth soften and weaken the cervical tooth surface, making the tooth surface susceptible to the effects of abrasion, leading to the formation of NCCLs. This usually arises when patients brush their teeth after a meal of fruits or fruit juices.

Abfraction

In the last twenty years, an alternative hypothesis has been proposed for the formation of NCCLs. Numerous studies have suggested that

, a term coined by Grippo might contribute to the formation of NCCLs. Abfraction has been reported to be the loss of tooth substance due to the “biomechanical loading forces that result in flexure and failure” of tooth structure “at a location away from the loading”.Sarode GS, Sarode SC. Abfraction: A review. Journal of oral and maxillofacial pathology : JOMFP. 2013;17(2):222–7. Numerous studies have suggested that occlusal loading results in the deformation and flexure of the tooth, creating a large amount of stress in the cervical region of the tooth. The persistent stress exerted on the tooth surface creates microfractures on the tooth structure, resulting in tooth breakdown and hence formation of NCCLs. However, despite many

literature review A literature review is an overview of the previously published works on a topic. The term can refer to a full scholarly paper or a section of a scholarly work such as a book, or an article. Either way, a literature review is supposed to provid ...

s supporting

as a contributing factor to the formation of NCCLs, one key clinical finding has significantly put into question the evidence used to support the

theory. The evidence used to back the abfraction theory were primarily obtained from finite element analyses. The

finite element The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, heat t ...

studies conducted suggest that based on the

theory, lingual surfaces of teeth should be equally susceptible to

cervical In anatomy, cervical is an adjective that has two meanings: # of or pertaining to any neck. # of or pertaining to the female cervix: i.e., the ''neck'' of the uterus. *Commonly used medical phrases involving the neck are **cervical collar **cerv ...

wear as the buccal surfaces. However clinical findings reveal lingual NCCLs are much rarer than buccal NCCLs, this means that there is little clinical evidence showing the causal relationship between occlusal stress and NCCLs. More research on this subject matter has to be conducted before the

theory can be recognised as a cause of NCCLs. ----

Archaeological non-carious cervical lesions

When NCCLs are present in

archaeological Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...

samples they can provide insight into behaviour and diet. Abrasion is the most common mechanism of NCCLs observed in archaeological samples, and results from non-

masticatory Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, th ...

contact of an object with teeth, often through cultural or therapeutic behaviour. Most NCCLs in archaeological examples are attributed to abrasion, with ‘toothpick grooves’ particularly common. Less commonly

acid erosion Acid erosion is a type of tooth wear. It is defined as the irreversible loss of tooth structure due to chemical dissolution by acids not of bacterial origin. Dental erosion is the most common chronic condition of children ages 5–17, althou ...

can cause NCCLs, and is caused by the chemical dissolution of dental tissues by acids of non-bacterial origin, most commonly low pH diets.

Abfraction Abfraction is a theoretical concept explaining a loss of tooth structure not caused by tooth decay (non-carious cervical lesions). It is suggested that these lesions are caused by forces placed on the teeth during biting, eating, chewing and grin ...

, is almost never seen in the pre-modern samples, leading some researchers to suggest it is a uniquely modern issue caused by recent dietary and behavioural changes.

Epidemiology

There is wide variation in the reported worldwide prevalence rates of NCCLs. According to the literature, the NCCL prevalence ranges from 9.1% to 93% in adults aged 16–75 years. The worldwide weighted average prevalence of NCCLs among adults is 46.7%. When geographical regions are compared,

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

has the highest reported prevalence of NCCLs, whilst the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

has the lowest. Studies show a tendency for prevalence to increase with age. The older the population studied, the greater the percentage of

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classifi ...

s found, the greater the number of

s per individual and the larger the

s. Many studies also show a link between good

oral hygiene Oral hygiene is the practice of keeping one's mouth clean and free of disease and other problems (e.g. bad breath) by regular brushing of the teeth (dental hygiene) and cleaning between the teeth. It is important that oral hygiene be carried out ...

and a higher frequency of NCCLs. People who brush twice daily have a statistically significant higher prevalence of NCCLs than those who brush less frequently.

Diagnosis

Due to the multi-factorial aetiology of NCCL, a comprehensive medical and dental history is imperative in ensuring an accurate clinical

diagnosis Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engin ...

. This includes obtaining information about the patient’s diet, social history, lifestyle and brushing habits. A systematic review by Teixeira et al. reported that most diagnoses of NCCL are derived from a combination of visual and tactile clinical examinations under adequate illumination. This is depicted as a clinical loss of mineralized dental tissue at the

cementoenamel junction The cementoenamel junction, frequently abbreviated as the CEJ, is a slightly visible anatomical border identified on a tooth. It is the location where the enamel, which covers the anatomical crown of a tooth, and the cementum, which covers the ...

(CEJ) in the buccal or lingual dental surfaces. There is also a consensus that visual dentine exposure is a reliable indicator of loss of tooth tissue. Tactile clinical examination involves running an exploratory probe laterally against the cervical surfaces of the tooth at the location of the suspected lesion. The lesion should feel smooth and non-cavitated.

Diagnostic Criteria

Aw TC et al. summarizes the diagnostic clinical characteristics of NCCLs based on an in vivo investigation carried out on 57 patients and 171 teeth. These are described in the table below: The Smith and Knight Tooth Wear Index (1984) can be used in combination with visual and tactile examination to grade extent of

tooth wear Tooth wear refers to loss of tooth substance by means other than dental caries. Tooth wear is a very common condition that occurs in approximately 97% of the population. This is a normal physiological process occurring throughout life; but with in ...

. It seeks to monitor and measure all types of tooth wear, regardless of how it occurred. Furthermore, it measures acceptable and pathological levels of wear by putting the results against threshold normal values of the particular age group studied. Teixeira et al.’s systematic review highlights that 19 out of 24 studies used visual and tactile examination as diagnostic assessment while 4 studies conducted in Asia used the Smith and Knight Index. After an initial diagnosis has been established, monitoring through intra-oral photographs, study casts, and tooth wear indices should be done regularly before formulating a definite diagnosis and appropriate management.

Treatment

In order for NCCLs to be treated effectively and to ensure longevity, the cause of the

should be deduced and this factor eliminated. Otherwise the treatment may be limited to only palliative care involving monitoring and efforts to minimise growth of the lesion. Primary indications for intervention in NCCLs include: poor aesthetics,

dentine hypersensitivity Dentin hypersensitivity (DH, DHS) is dental pain which is sharp in character and of short duration, arising from exposed dentin surfaces in response to stimuli, typically thermal, evaporative, tactile, osmotic, chemical or electrical; and which c ...

and food stagnation. There may also be a requirement for treatment if the

affects the design of a partial denture. Treatment of NCCLs to relieve symptoms of

involve either chemical or physical occlusion of the

dentinal tubules Bone canaliculi are microscopic canals between the lacunae of ossified bone. The radiating processes of the osteocytes (called filopodia) project into these canals. These cytoplasmic processes are joined together by gap junctions. Osteocytes do ...

.Moraschini V, da Costa L, dos Santos G. Effectiveness for dentin hypersensitivity treatment of non-carious cervical lesions: a meta-analysis. 2022. Direct resin composite restorations are used commonly in dentistry and are effective in treating aesthetic issues as they are tooth coloured.Chee B, Rickman L, Satterthwaite J. Adhesives for the restoration of non-carious cervical lesions: A systematic review. 2022. The success of a resin composite

restoration Restoration is the act of restoring something to its original state and may refer to: * Conservation and restoration of cultural heritage ** Audio restoration ** Film restoration ** Image restoration ** Textile restoration * Restoration ecology ...

does not rely greatly on traditional tooth preparation involving mechanical retention from the cavity. Instead adhesion to tooth structure is utilised. This makes

composite resin Dental composite resins (better referred to as "resin-based composites" or simply "filled resins") are dental cements made of synthetic resins. Synthetic resins evolved as restorative materials since they were insoluble, of good tooth-like appea ...

the treatment option of choice in the case of NCCLs as the lesions offer minimal retention or resistance form naturally and would require further tissue removal for this to be achieved. Choosing resin composite to treat NCCLs protects the teeth from further loss of healthy tooth structure.Rocha A, Da Rosa W, Cocco A, Da Silva A, Piva E, Lund R. Influence of Surface Treatment on Composite Adhesion in Noncarious Cervical Lesions: Systematic Review and Meta-analysis. Operative Dentistry. 2018;43(5):508-519 NCCLs are located mainly in

dentin Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by ena ...

e and most adhesive processes rely on adhesion to enamel. Sclerotic dentine compromises the

as it is difficult to bond

to this type of tissue. This has led to discussions around tooth surface treatments of NCCLs prior to the

being placed. Surface irrigation with

EDTA Ethylenediaminetetraacetic acid (EDTA) is an aminopolycarboxylic acid with the formula H2N(CH2CO2H)2sub>2. This white, water-soluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-soluble complexes eve ...

works to remove the

smear layer In dentistry, the smear layer is a layer found on root canal walls after root canal instrumentation. It consists of microcrystalline and organic particle debris. It was first described in 1975 and research has been performed since then to evaluate i ...

from the cavity to allow bonding of the

. Studies have shown that application of the adhesive with a frictional technique has also increased adhesion. Treatment of NCCLs can also be carried out with

glass ionomer Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...

References

{{reflist Acquired tooth disorders Osteology