Composite Class V Restorations

Lesion-Specific Approaches

Introduction

A disappointing and all too common finding with class V composite restorations is discolored or leaking margins, gingival overhangs, and complete loss of retention.  These unfortunate failures often occur soon after placement.  Class V composite restoration failures lie in overconfidence with dentin bonding, a complete lack of standardized preparation designs, poorly understood materials properties, inadequate force management, and other intrinsic and extrinsic patient factors, including abfraction, abrasion, erosion, and plaque control.  This paper strives to associate etiological findings with appropriate preparation designs for each situation and restoration protocols that match the specific needs of the lesion in question.

The True Class V Lesion

Over 100 years ago, G.V. Black established the cavity classification system and based the nomenclature on the frequency of the etiology, with Class I lesions being more prevalent than Class II lesions, all the way to the least common, the Class V Lesion.  Very little has changed today, as the G.V. Black cavity was always explained to be the result of poor brushing and the accumulation of plaque along the facial and lingual surfaces of teeth.  The lesions were clearly defined as enamel lesions and were attributed to patients with the most compromised oral health.

Today, we use Class V Lesion to describe the various “gumline” preparations and restorations with (in most cases) composite resin.  This use of the dental nomenclature may result in less-than-optimal dental outcomes if it is not fully understood.

The true Class V Lesion is caused by a bacterial infection and originates in enamel due to poor plaque control.  These lesions are uncommon in healthy patients with a reasonable ability to perform routine brushing.

Keys to Sucess

  1. Confirm diagnosis, establish risk assessment, develop an approach for longevity
  2. Isolate with rubber dam, when possible, otherwise consider retraction cords with an isolation system (Isolite etc.)
  3. Understand that caries risk and need for retention will determine the preparation shape
  4. Use butt-joint cavosurface margins when in dentin
  5. Bevel the enamel when present for increased retention
  6. Place retention grooves or undercuts in dentin
  7. Use RMGI liner only on dentin surfaces and to flow into retention areas
  8. GI/RMGI restorations may be veneered with composite if esthetics is a factor

The 3 Types of Class V Cavities

Each Type of Lesion Requires a Different Treatment Approach

Class V G.V. Black enamel only lesion Stevenson Type EE
Entirely in ENAMEL [Stevenson Type EE], a true GV Black lesion
Enamel caries
Primary cause: bacterial infection due to poor plaque control
NOTE: May extend onto root (treat like Stevenson Type ED)
Class V NCCL lesion Stevenson Type ED
Occlusal/Incisal Wall in ENAMEL, Gingival Wall in DENTIN [Stevenson Type ED], an NCCL
Primary Causes: abfraction, abrasion, erosion
Class V root caries lesion Stevenson Type DD
Entirely in DENTIN [Stevenson Type DD], Root Caries
Primary cause: bacterial infection due to xerostomia and/or poor plaque control

Type-Specific Preparation Designs

Class V composite enamel only preparation design
Caries driven
Concave Beveled enamel

In this lesion, the decay starts in the enamel due to bacterial infection (a true G. V. Black Class V). The margins may spread onto the root surface in advanced lesions. The key to understanding this Stevenson Type EE is that both the occlusal/incisal and gingival margins are contained within the enamel. The caries will often penetrate deeply into dentin; however, the root surface is typically not impacted. The preparation will use the surrounding enamel as the primary contributor to restoration retention. The dentin area will be prepared simply to remove the caries, with no further box form required. The final shape may be concave with no retention grooves. Please note that when the root is involved, the lesion would be treated like the ED lesion in the next section.
Class V composite NCCL preparation design
Caries driven
Concave Beveled enamel

In the ED lesion (also termed an “NCCL”), the initial cause of the tooth structure loss is either abrasion, erosion, abfraction, or a combination of two or three of these. This is by far the most prevalent lesion types (EE, ED, and DD). The exact etiology may not be easy to determine, as overlying conditions such as GERD and aggressive tooth brushing may co-occur or be the cause but have different disease occurrences and trajectories. The key to understanding the Stevenson Type ED is that the occlusal/incisal margin is in enamel and the gingival margin is in dentin. Since the greatest threat to the long-term survival of this type of restoration is non-carious events (like occlusal forces, brushing habits, and intrinsic and extrinsic acid exposure), retention is of paramount importance. Dentin bonding alone is not able to seal the gingival margin of the NCCL restoration with any degree of certainty. Retention grooves and box forms are indicated in high-stress areas when margins are in dentin. The occlusal/incisal margin is in enamel in the Stevenson Type ED lesion, which would be beveled like in the EE lesion. Combining the dentin box form and grooves at the gingival and the enamel bevel at the occlusal/incisal creates a robustly retentive preparation design.
Class V composite root caries preparation design for RMGI/GI
Protection driven
Retentive in dentin
Beveled enamel
In the DD lesion, the terminology would be better stated as “Root Caries” and not a Class V lesion. Although caries is the primary cause of the root caries lesion, patients who have experienced relatively early recession may have an NCCL type of lesion with no caries. In both situations, the preparation design will be entirely located within dentin and will require definite macro-retention features to obtain the best results. Using a box form preparation with retention grooves would be one predictable way to achieve retention, when bonding alone would not provide a long-term result.
It is important to note that retention today is afforded by both macro and micromechanical methods, which simply means that the restorative materials themselves will participate in the overall retention form.

Three Different Restoration Protocals

Each Type of Lesion Requires a Different Treatment Approach

Class V G.V. Black composite restoration
Composite Resin

Class V composite NCCL restoration with RMGI liner
Dentin RMGI Liner
Composite Resin

Class V composite root caries restoration with RMGI liner and RGMGI/GI restorative
GI/RMGI Restoration

True Class V Enamel-initiated Lesions Stevenson Type EE

The greatest threat to this type of restoration is recurrent decay, and the enamel seal of the composite will provide an excellent barrier, especially when combined with caries management strategies.

STEPS

    1. Complete the caries driven preparation
    2. Bevel the enamel periphery
    3. Place RMGI on deep dentin (D2, or over 1 mm into dentin)
    4. Etch the enamel, mitigate MMPs with Chlorhexidine 2% for 120 seconds
    5. Place adhesive
    6. Place composite resin of choice in layers when indicated

References

Matis B, Cochran M, Carlson T, Longevity of glass-ionomer restorative materials: Results of a 10-year evaluation, Quin International, Vol 27, No 6, 1996

Collares, Opdam et al., Longevity of Anterior Composite Restorations in a General Dental Practice-Based Network J Dent Res 2017 Sep;96(10):1092-1099

Demarco et al., Anterior composite restorations: A systematic review on long-term survival and reasons for failureDent Mat, v 31:10, Oct 2015, 1214-1224