EDTA-S: A novel root conditioning agent

Abstract

Background:

To evaluate the efficacy of 15% ethylenediaminetetraacetic acid (EDTA)-S (EDTA with soft soap) preparation for the removal of smear layer at human root surfaces.

Materials and Methods:

Twenty teeth indicated for extraction due to periodontal disease were sectioned using high speed cylindrical bur under copious irrigation. The root surfaces were instrumented with Gracey 7-8 curette (Hu-Friedy), 12 times to induce an “experimental smear layer”. Following root planning, the root surface was cut using diamond disc and separated from the crown. Samples were randomly distributed into five groups. One group was control, saline and test groups were EDTA 15% alone, by active and passive applications (groups 2 and 3), and EDTA 15%+soft soap, by active and passive applications (groups 4 and 5). Specimens were then subjected to scanning electron microscope study. Smear layer removal was evaluated according to Sampaio et al., index.

Results:

EDTA-S removed the smear layer better than plain EDTA and the control group, while active application of the root conditioning agent had significant difference than the passive application of the agent.

Conclusion:

EDTA-S has favorable benefits over EDTA alone, and active application is better in comparison with passive application of root conditioning agent.

Clinical Relevance:

Removal of smear layer has been considered as an important step in periodontal regenerative therapy. Scaling and root planning alone with saline irrigation does not remove the smear layer. EDTA is a commonly used root conditioning agent in periodontal therapy. The addition of a detergent to EDTA proved to remove smear layer more efficiently than EDTA alone.

INTRODUCTION

Traditional surgical and non-surgical periodontal therapies aim at arresting periodontal disease by removal of plaque from disease affected roots. However, complete removal with only mechanical debridement is not feasible.[1] Thus, etching has been recommended as an adjunct to mechanical root surface debridement to remove smear layers and root-associated endotoxins,[2–4] and to expose collagen fibers on the dentin surface.[2] However, concerns have been expressed regarding the possible necrotizing effect on surrounding vital periodontal tissues of etching agents operating at low pH,[5] and thus, etching at neutral pH with calcium chelating agents such as ethylenediaminetetraacetic acid (EDTA) have been explored giving favorable results with respect to less flap failure and more connective tissue attachment.[6]

Several studies have shown that contaminated cementum as well as the smear layer inhibit cell migration and attachment leading to impaired marginal periodontal healing.[7,8] However, both histological and clinical surgical studies have presented contradictory results regarding the success of marginal periodontal healing following etching, and thus, the rationale for routine use of etching in conventional periodontal therapy has been questioned.[9] Nevertheless, in regenerative procedures where recolonization of large areas of the root surface by periodontal connective tissue is a necessity, removal of the smear layer is of singular importance.[9] In addition, etching has been reported to expose collagen fibers on the root surface.[10,11] Etching at neutral pH was shown to preserve tissue vitality, while etching at low pH induced an immediate necrosis. It was concluded that etching at neutral pH appeared in the short-term perspective to produce a more biocompatible surface compared to etching at low pH.[5]

Etching of such a surface may yield variable results compared to the more homogenous dentin exposed after scaling and root planning.[12] Cell and fiber attachment to healthy cementum surfaces in vitro is facilitated by citric acid etching.[13] Although the same is not seen after etching of periodontitis affected cementum surfaces, cementum bound endotoxin is capable of both cell death and decrease cell proliferation.[14] Smear layer is resistant to saline irrigation and the effect of EDTA alone has already been proven. The addition of texapon, a derivative of sodium lauryl sulfate (SLS) with EDTA, has shown to provide better smear layer removal than EDTA alone.[15] Soft soap, a detergent, belongs to the SLS family and is cost effective. Hence, the aim of the present in vitro study is to evaluate the efficacy of 15% EDTA-S (EDTA with soft soap) preparation for the removal of smear layer at human root surfaces.

MATERIALS AND METHODS

Twenty teeth (molars) indicated for extraction, due to periodontal disease were obtained from the Department of Diagnosis and Oral surgery at the S.D.M.C.D.S, Dharwad. After extraction, the teeth were stored in a container with saline solution to avoid dehydration of the specimens. Using high speed cylindrical bur under copious irrigation, two parallel retention grooves were made on the root surface, one at Cemento-enamel junction (CEJ) and other 4 mm apical to the first groove. The CEJ was taken as the reference. Cervical cementum was removed by the same bur. An experimental smear layer was induced by instrumenting the root surfaces 12 times with Gracey 7-8 curette (Hu-Friedy). Following root planning, the root surface was cut using diamond disc and crown was separated from the root. All root conditioning agents were drawn in a 5 ml syringe (15% EDTA, saline control, and 15% EDTA with soft soap 1:1 concentrate). Samples were then randomly divided into five groups; one sample from each group was randomly selected for the application of root conditioning agent. The efficacy of two different methods of application –active application with brush and passive with cotton pellet was also assessed.

One sample acted as the control (saline). The samples were treated with the test and the control agents and allowed to dry for three min. After lapse of the allotted time interval, the specimen was thoroughly irrigated with copious amount of saline. The specimens were dried overnight using silica gel crystals. The specimens were then mounted on metallic stubs, coated with 20 nm of gold (ion sputtering) for observation and photography by Scanning Electron Microscopy (JEOL JSM 840A) at 3500 for the presence or absence of smear layer.

Data analysis

Smear layer removal was evaluated according to Sampaio et al., index.[15]

1. Root surface without smear layer, with the dentinal tubules completely opened without evidence of smear layer in the dentinal tubules

2. Root surface without smear layer, with the dentinal tubules completely opened, but with some evidence of smear layer in the dentinal tubules entrance

3. Root surface without smear layer with the dentinal tubules partially opened

4. Root surface covered by a uniform smear layer with evidence of dentinal tubule opening

5. Root surface covered by a uniform smear layer without evidence of opening of the dentinal tubules

6. Root surface covered by an irregular smear layer, with the presence of grooves and or scattered debris

RESULTS

Scanning electron microscope of the control group revealed a root surface covered by an irregular smear layer, with the presence of grooves and or scattered debris. The EDTA groups, both passive and active applications, revealed open dentinal tubules with evidence of smear layer present. The EDTA-S groups with active application revealed completely open dentinal tubules with no evidence of smear layer, whereas EDTA-S passive application revealed open dentinal tubules with evidence of smear layer present [Figures 1–5].

Figure 1.

Control group (saline) for three minutes. Presence of heavy smear layer (score-6)

Figure 5.

15% EDTA-S group: Active application for three minutes. Root surface devoid of smear layer with evidence of dentinal tubules opening, but no evidence of smear layer at dentinal tubule opening (score-1)

Figure 2.

15% EDTA group: Passive application for three minutes. Root surface covered by smear layer with evidence of dentinal tubules opening (score-4)

Figure 3.

15% EDTA-S group: Passive application for three minutes. Root surface covered by smear layer with evidence of dentinal tubules opening (score-4)

Figure 4.

15% EDTA group: Active application for three minutes. Root surface devoid of smear layer with evidence of dentinal tubules opening, but some evidence of smear layer at dentinal tubule opening (score-2)

DISCUSSION

The purpose of this study was to assess the efficacy of EDTA preparation with soft soap, a detergent in removing the smear layer on the root surface of human teeth. Several authors have shown that three minute etching with EDTA is sufficient for the removal of smear layer compared to 10, 20, 30, 40 sec, and 1 and 2 minutes.[5]

On the other hand, soft soap is widely used in the medical field to remove incrustation in scaly skin diseases; it is also used in solution form with warm water as an enema and this signifies its reaction with the mucous membranes and degree of safety. Hence, an attempt was made to incorporate the advantages of EDTA and detergent like soft soap.

The addition of soft soap, a tense active detergent, decreases the surface strain.[15] Batista et al., 2005 achieved better results with 15% EDTA-T (texapon) in comparison with EDTA alone and found it to be statistically similar at 20% and 24% EDTA-T. Hence, in this pilot study, we used 15% EDTA-S; further studies are required to evaluate removal of smear at varying concentrations and time of application.

The optimal pH for vital fibroblast cell function varies between 7.2-7.4, though some cells may tolerate pH of 6.6-7.8. EDTA provides a biocompatible cell surface for cell and tissue attachment. Demineralized root surfaces serve as a reservoir of biologically active extracellular matrix proteins and growth factors which are essential for bone and cementum formation.[16]

We also found that smear layer removal by active application was better than passive application, which was in conjunction with the study by Pilatti et al. (2005). The application with the brush seems to provide a larger surface area compared to application by cotton pellet. Thus, the method of application also plays an important role in determining the success of root conditioning.

CONCLUSIONS

1. The etching of surface with EDTA is more effective than saline solution (control group).

2. EDTA 15% is more effective, when mixed with soft soap than when used alone.

3. Active application of 15% EDTA-S was more efficacious than passive application.