A Minimally Invasive Approach to Treating Non-Cavitated Carious Lesions
We find seemingly intact enamel surfaces in the examination of our pit and fissure teeth every day (Fig. 1 at left). These areas come in a variety of depths and colors. Without a positive stick from an explorer, most of us dismiss them in our adult patients as asymptomatic stains.
Does that mean they are really just that—deep crevices that easily stain? Or are they the ongoing disease process known as the non-cavitated carious lesion? A non-cavitated carious lesion is a carious lesion that is commonly found beneath the fissures and pits of posterior teeth.
Diagnostic challenge
The non-cavitated carious lesion is not a new problem. Originally documented by J Knapp in 1868 (Hidden dental caries. Am Dent Assoc Trans 8:108–112), and later published by GV Black in a series of papers from 1880-1924, this problem has been well known for more than a century. The problem is further compounded because decay is difficult to detect in radiographs unless larger than 2 mm to 3 mm deep into dentin, or 1/3 the bucco-lingual distance. They cannot be diagnosed by mirror, probe or radiographic examination.
Tools of the trade
Currently, there are two reliable methods for determining the presence of these hidden lesions: caries dye and laser detection unit. Fusayama discovered that caries detection dye works by filling the voids in enamel and dentin that are created by acid attack. More recently, the DIAGNOdent pen has been used with great success. It reads the fluorescence of tooth structure and other materials. A 655 nm diode laser, the DIAGNOdent pen can diagnose this zone in the fissure by reading 2 mm into the tooth (Fig. 2 above). By detecting the fluorescence of decay, an audible alarm and numerical display give a reading for the positive presence of decay.
Caries removal
Once the presence of decay has been diagnosed, caries can be removed conservatively with air abrasion, which minimally opens the pits and fissures (Fig. 3 at left).
This prevents the greater loss of healthy enamel and dentin compared to initial bur access. Air abrasion units can be purchased as a fixed unit such as the RONDOflex plus 360 or as the highly affordable PrepMaster®.
Cavity prep
Once access has been made, the lesion can be further widened (Fig. 4 above left) using a conservative rotary bur—in this case, the Fissurotomy Carbide Burs. The prep is stained with caries detection dye (Fig. 5 above right) and remaining caries is conservatively removed with a stainless steel round bur set at 300 rpm (Fig. 6 below left). This process is repeated until the caries detection dye no longer stains tooth structure (Fig. 7 below right).
Surface conditioning
The restoration of these lesions is just as important as their discovery and removal. A combination of etching agents and restorative materials will secure a future for a healthy tooth and your peace of mind. All areas of tooth structure beside the outer rim of enamel are etched with Cavity Conditioner (Fig. 8 at right). This mild etchant has many features and benefits that include:
- 20% Polyacrylic Acid
- Removes smear layer and debris for improved bonding
- Eliminates Sensitivity
- Aluminum chloride hexahydrate component seals tubules
- Deep Blue Tint for easy Visibility
- 10 Second Application Rinse Away Thoroughly
- Blot Dry Before Using Glass Ionomer
While the Cavity Conditioner is etching, any 35%, 37% or 40% phosphoric acid etch can be applied to the outer rim of enamel only. Both etchants are rinsed away simultaneously and the prep is gently dried.
Cavity lining
Fuji IX GP EXTRA, a resin modified glass ionomer, is placed as a base into the cavity preparation (Fig. 9 above). Compared to its predecessors, this material offers many advantages including shade matching capability, higher translucency, high fluoride release, good handling, high physical properties and rapid setting time. This material can be manipulated and pressed into the floor of the cavity preparation using a ball or round shaped composite instrument dipped into G-Bond, a self-etching-primer-bonding agent specifically designed for situations such as this (Fig. 10 above).
Bonding
The G-Bond is further brushed against the remaining surfaces of the cavity preparation, dried and light cured. It is the G-Bond that offers a dual purpose. It forms the bond that will allow composite resin to adhere to the glass ionomer base and becomes the resin bonding agent in the remainder of the cavity preparation as well.
Filling
A flowable composite resin is injected against the Fuji IX GP EXTRA (Fig. 11 below left) and cured followed by the placement and curing of 2 mm increments of composite resin paste. One of my favorites is GRADIA™ DIRECT. Its increased radiopacity and enamel translucency make it a true biomimetic material.
Figure 12 (above right) illustrates the cured composite being finished. Figure 13 (below left) shows before and after radiographs. Figure 14 (below right) is the final result. These techniques offer you a method for early intervention, help you avoid sensitivity and create a very grateful patient.
