Stuart Campbell assesses the effectiveness of variety of different clinical techniques in the management of soft tissues, highlighting potential pitfalls along the way

Management of the soft tissues is a frequent challenge for the restoring dentist. An effective marginal seal is essential so that a restored tooth is protected from recurrent caries and gingival irritation. Overgrown gingival tissues must be effectively managed as they can create an obstacle to achieving marginal accuracy in direct and indirect restorations.

There are several clinical techniques to facilitate soft tissue management for direct and indirect restorations:

• Mechanical

• Surgical

• Chemico-mechanical.

Mechanical

Hovestad first described techniques to physically displace the gingivae in õ924. These techniques were based on the use of a copper band filled with impression compound which displaced the free gingival margin.

Contemporary versions of this technique make use of preformed cotton wool cones which are filled with a non-haemostatic polyvinylsiloxane impression material (Magic FoamCord – Coltene Whaledent) (Fig õ). Beier has reported that this technique may be a less traumatic means of gingival retraction compared with retraction cord.

Surgical

Gingival rotary curettage describes a technique where a rotary instrument is used to remove a limited amount of epithelial tissue creating a wider gingival sulcus. The technique is indicated for placement of subgingival preparation margins, and gaining access to deep cervical lesions. Ceramic burs (Tissue Trimmers, NTI) designed for use in the air rotor at 300,00-500,000 rpm without coolant have been marketed for this technique (Fig 2).

The technique has been associated with a greater incidence of gingival recession compared with other means of soft tissue control. For this reason rotary curettage should only be carried out on healthy, inflammation-free tissue because of the shrinkage that occurs when diseased tissue heals.

Electrosurgery can be used to remove inflamed, overgrown tissue, widen the gingival sulcus to facilitate impression taking, remove opercula and reshape inflamed tissue. A current is directed to a small cutting electrode, producing a rapid temperature rise at its point of contact with the tissue. Concerns have been raised about the potentially damaging effects of elevated temperatures created by this technique on the alveolar bone.

Furthermore, electrosurgery is contra-indicated in patients with cardiac pacemakers and additional training in the proper use of the technique-sensitive equipment is recommended.

The use of the CO2 laser has been described as being an extremely effective technique for the management of soft tissue. Compared with the previously mentioned surgical techniques, reduced inflammation, post-operative discomfort and a bloodless field have been reported as the main advantages of the CO2 laser. However, the relatively high cost, lack of tactile feedback during operation, further training requirements and the risk of eye injuries have been cited as barriers to the widespread use of lasers in general practice.

Chemico-mechanical

This technique has been described as the most commonly used form of soft tissue management and typically combines the use of a compound which induces haemostasis and temporary shrinkage of the tissues together with a retraction cord which physically displaces the tissues.

Several chemicals have been described for use with retraction cord:

• epinephrine (adrenaline)

• aluminium chloride

• aluminium sulphate

• ferric sulphate.

Although adrenaline has been used in conjunction with retraction cord for many years, concerns have been raised regarding the possible negative cardiovascular effects produced by adrenaline impregnated cords. For this reason, and the fact that adequate retraction can be achieved using alternative compounds, the use of adrenaline impregnated cords is no longer recommended.

Aluminium chloride (Alustat, QED) has been described as an extremely effective compound for retracting soft tissues and for controlling haemorrhage without the production of systemic side effects. An injectable paste form of aluminium chloride in a kaolin matrix (Expasyl, Kerr) has been marketed as an alternative to retraction cord and chemical retraction materials.

The advantages of this technique are as follows:

• painless control of soft tissues

• does not damage the healthy periodontium

• green coloured paste is easily seen and removed from the gingival sulcus.

However, it has been reported that Expasyl produces greater amounts of post-operative gingival inflammation and is not as effective at displacing the gingivae as compared to retraction cord and chemical retraction materials (Fig 3).

Aluminium sulphate (Gingi-Aid, Belport Co) and ferric sulphate (Viscostat, Ultradent) have both demonstrated excellent haemostatic ability, control of tissue fluids and temporary shrinkage of the soft tissues. However, recent research, has reported the cytotoxic effects of both of these materials. Wassell et al have observed severe gingival inflammation and tissue necrosis when aluminium sulphate astringents are used to aid tissue management.

Chemico-mechanical methods of tissue management are readily available, easily practiced and provide reliable results. However, there are risks of damage to the soft tissues with an improper technique.

A systematic approach to chemico-mechanical tissue management has been described.

The cord must first be prepared. I prefer Ultrapack cords (Ultradent) which are available in sizes 00,0,1 and 2 (Fig 4). These cotton cords are non-impregnated, easily inserted, colour coded, can be soaked as desired and are easily differentiated from the ginigivae.

Cords are cut into lengths appropriate to the tooth or teeth to be isolated. Suitable lengths have been recommended by Wise (see table below).

A double cord technique has been shown to be more effective for tissue management than using a single piece of cord. For this reason, two lengths of cord of different thickness are cut. A length of 00 cord is cut and laid aside, a length of either 0,1 or 2 cord is cut and soaked in a Dappens dish containing astringent solution for 10 minutes (Fig 5).

After this time, the cord is dabbed against a facial tissue to remove excess solution.

The clinician now takes the non-impregnated 00 cord and places it at the gingival margin. The cord is packed into the gingival sulcus using a Fischer UltraPak Packer. This instrument has a serrated edge allowing for effective cord placement (Fig 6).

The 00 cord is packed to its full thickness, starting from the mesial or distal surface so that the overlapping cord ends are not located on the buccal aspect of the tooth. The 00 cord can be left in place during impression-taking, the placement of direct restorations and when finalising preparation margins.

The thicker impregnated cord (0, 1 or 2) is then packed into the gingival sulcus to half of its thickness. The thicker cord is packed on top of the 00 cord and is left in place for no longer than five minutes. It is removed prior to impression taking or placement of direct restorations.

This technique facilitates the temporary retraction of overgrown gingivae, placement of subgingival marginal finishing lines, accurate impressions and haemostasis.

Case study

A 57-year-old gentleman presented in practice with a lost direct composite restoration from unit 13. The patient reported no symptoms from the tooth but was anxious for a cosmetic replacement as he had a job interview the next day.

The patient’s medical history was unremarkable. He had a medium lip-line but the lost restoration in 13 was clearly visible during conversation.

The intra-oral examination revealed a heavily restored but intact dentition. Unit õ3 was root filled and restoration of the tooth was complicated by localised gingival overgrowth (Figs 7 and 8).

To comply with the patient’s wishes of an expedient cosmetic restoration, a direct composite restoration was planned. Management of the soft tissues and haemostatic control were planned using a double retraction cord technique.

An adrenaline containing local anaesthetic was infiltrated around 13 and the defective restoration removed. The cavity was assessed for caries removal using caries indicator dye (Snoop, Pulpdent).

Once caries removal was complete, a shade was agreed with the patient. A 30mm length of 00 retraction cord was cut and packed to its full thickness in the gingival sulcus, using the technique described. A second 30mm length of size 1 cord was soaked in astringent (Viscostat) for 10 minutes, then packed to into the gingival sulcus as before (Fig 9).

Once control of the overgrown gingiva and localised bleeding was assured, a clear mylar strip was placed. The cavity was etched and rinsed, dentine was rehydrated and a fifth generation bonding agent was placed (Scotchbond, 3M Espe). A direct composite restoration (Filtek Supreme, 3M Espe) of the appropriate shade was placed using an incremental technique. A final cure was carried out after the appication of glycerin. Final finishing and polishing was completed using composite finishing burs, polishing discs, interproximal strips and silicone points (Figs 10-13).

The effective management of overgrown soft tissue is a prerequisite for direct and indirect restorative procedures. Several techniques are available to the clinician to achieve this aim. This case study demonstrates a systematic approach to the double retraction cord technique which provides an effective, economical and simple method of tissue management and haemostatic control for restorative procedures.

About the author

Stuart Campbell qualified from University of Dundee in 2001 and is a vocational trainer and partner at Loanhead Dental Practice in Midlothian. He is currently studying for an MSc in Implant Dentistry at the University of Central Lancashire.