Class V Caries: Causes, Diagnosis, and Management

Class V caries form along the gingival third of the tooth, often on both facial and lingual surfaces. These lesions are challenging to manage due to their location and contributing factors such as mechanical abrasion, chemical erosion, and bacterial activity.

Early identification and treatment are essential to prevent progression and structural compromise. Understanding the causes, diagnosis, and management of Class V caries is crucial for effective intervention and long-term oral health.

Anatomical Locations

Class V caries develop along the cervical third of the tooth, where enamel transitions to cementum near the gingival margin. This region is particularly susceptible to decay due to plaque accumulation and challenges in mechanical cleaning. Lesions frequently appear on the facial and lingual surfaces of anterior and posterior teeth, with a higher prevalence on premolars and canines due to their exposure to occlusal forces and oral hygiene challenges.

The cervical region’s structural composition contributes to lesion development. Enamel in this area is thinner, making it more vulnerable to acid dissolution and mechanical wear. As the lesion progresses, it may extend into the cementum and dentin, which are less mineralized and degrade more rapidly. Gingival recession further increases susceptibility by exposing root surfaces that lack enamel.

Salivary flow and oral biomechanics influence lesion distribution. Lower anterior teeth benefit from continual saliva exposure, which aids remineralization. In contrast, the buccal surfaces of maxillary premolars and molars are more exposed to dietary acids and abrasive forces from toothbrushing, increasing their risk for lesion formation. While less frequently affected, lingual surfaces can still develop caries in individuals with poor oral hygiene or reduced salivary flow.

Etiological Factors

Class V caries develop due to biological, mechanical, and chemical factors that compromise the cervical tooth structure. Unlike occlusal or proximal caries, which primarily result from bacterial activity in plaque-retentive areas, cervical lesions arise from a combination of demineralization, abrasion, and erosion.

Acidic environments contribute significantly to lesion initiation, particularly in individuals with high dietary acid intake or reduced salivary buffering capacity. Frequent consumption of citrus fruits, carbonated beverages, and acidic condiments lowers the pH, promoting demineralization. Saliva normally neutralizes acids and facilitates remineralization, but individuals with xerostomia or medication-induced dry mouth experience a higher prevalence of non-carious cervical lesions, which can predispose the area to bacterial colonization and caries formation.

Mechanical factors also play a role in susceptibility. Aggressive toothbrushing with abrasive toothpaste, especially with a horizontal scrubbing technique, leads to enamel and dentin wear. Medium- to hard-bristled toothbrushes used with excessive force accelerate mineral loss, creating an environment for plaque attachment and acid penetration. Gingival recession, whether due to periodontal disease or improper brushing, exposes the cementum, which is more vulnerable to acid dissolution and bacterial degradation.

Bacterial biofilms contribute to lesion progression, though differently from other caries. The gingival margin harbors microbial activity, where plaque accumulates due to reduced self-cleansing mechanisms. Acidogenic bacteria such as Streptococcus mutans and Lactobacillus metabolize carbohydrates into organic acids, further demineralizing the tooth. Unlike occlusal lesions that develop in deep fissures, cervical lesions progress through repeated cycles of demineralization and remineralization, with bacterial infiltration occurring once dentinal tubules are exposed.

Clinical Presentation

Class V caries appear as lesions along the cervical third of the tooth, often near the gingival margin. Early-stage lesions present as opaque, chalky white spots due to subsurface enamel demineralization. These lesions are more visible during routine examinations when air drying reveals mineral loss. Patients may report mild sensitivity to temperature changes or acidic foods, though symptoms are often subtle.

As the lesion progresses, cavitation occurs, and the affected area may appear yellowish or brown due to extrinsic staining and bacterial infiltration. The texture becomes roughened, and sensitivity to hot, cold, or sweet substances increases. This hypersensitivity arises from exposed dentin, where open tubules facilitate fluid movement, triggering nerve responses.

In advanced cases, cavitated lesions extend deeper into dentin, weakening the structure and increasing fracture risk. The affected area may develop a concave appearance, with softened dentin that can be easily probed. Patients often report persistent discomfort when brushing or eating, and gingival recession can further exacerbate sensitivity. If untreated, lesion progression can lead to pulpal involvement, increasing the risk of irreversible pulpitis or secondary infections.

Diagnostic Techniques

Diagnosing Class V caries requires visual inspection, tactile examination, and adjunctive diagnostic tools to differentiate them from non-carious cervical defects. Their location makes them readily visible, but early lesions can be subtle. A well-illuminated field and air drying help reveal initial white spot lesions that may not be apparent when the tooth is hydrated.

Tactile examination with an explorer provides information on lesion progression. Non-cavitated lesions may feel smooth or slightly rough, while cavitated areas exhibit surface loss. However, excessive pressure should be avoided to prevent further enamel breakdown or discomfort. Differentiating between carious and non-carious cervical defects requires evaluating lesion shape, surface texture, and patient history, including dietary habits and oral hygiene practices.

Adhesion Considerations

Restoring Class V caries presents challenges due to the cervical location and the nature of the involved tooth structure. Unlike occlusal or proximal restorations, which rely on enamel for bonding, the gingival third often includes dentin and cementum, both of which have lower mineral content and higher organic matrix. This affects adhesion, as traditional bonding techniques designed for enamel may not achieve the same retention on these substrates. Additionally, contamination from saliva and gingival crevicular fluid can compromise bond strength and lead to premature restoration failure.

To optimize adhesion, proper surface preparation and bonding strategy selection are essential. Etch-and-rinse systems provide strong enamel adhesion but may increase post-operative sensitivity when used on dentin. Self-etch adhesives incorporate mild acidic monomers that condition and prime dentin simultaneously, reducing sensitivity and improving bond durability. Two-step self-etch adhesives demonstrate better long-term performance in cervical restorations compared to one-step systems, which are more prone to hydrolytic degradation. Maintaining a dry field through isolation techniques, such as rubber dam placement or retraction cord use, enhances bond strength by minimizing contamination.

Material Options

Selecting the right restorative material is critical for durability and aesthetics. The choice depends on mechanical properties, biocompatibility, and the ability to withstand occlusal forces and environmental challenges in the cervical region. Since these lesions often occur in visible areas, particularly on anterior teeth, esthetics is also a key consideration.

Resin composites are widely used due to their ability to bond micromechanically to both enamel and dentin, providing durable and esthetically pleasing restorations. Advances in nanohybrid and microfilled composites have improved polishability and wear resistance, making them suitable for cervical restorations. However, polymerization shrinkage can lead to marginal gaps and secondary caries. Using incremental layering techniques and low-shrinkage composites can help mitigate this issue.

Glass ionomer cements (GICs) offer an alternative, particularly in cases where moisture control is difficult. These materials release fluoride, aiding remineralization and reducing recurrent decay risk. High-viscosity GICs exhibit improved wear resistance and are suitable for atraumatic restorative treatment (ART) approaches in high-caries-risk patients. Resin-modified glass ionomers (RMGIs) combine fluoride release with improved adhesion and esthetics, making them a versatile option. Their ability to bond chemically to dentin and lower technique sensitivity makes them beneficial for elderly patients or those with compromised oral hygiene.