Present status and future directions: Soft tissue management in prosthodontics

Abstract

During restorative dental procedures, complete control over the operative site is critical for patient comfort, safety, and the operator’s access and visibility. The success of a fixed prosthesis depends on accurate impression making of the prepared finish lines on the abutment teeth. To optimise long-term outcomes for the fixed restoration, gingival retraction techniques should be used to decrease the marginal discrepancy among the restoration and the prepared abutment. Accurate marginal positioning of the restoration along the prepared finish line of the abutment is essential for therapeutic, preventive, and aesthetic purposes.

Key Words: Soft tissue; Prosthodontics; Fixed prosthesis; Dentistry; Implants

Core Tip: The primary goal of soft tissue management in prosthodontics is to improve visibility and accessibility, particularly when working with complex or obscure microanatomy over an extended period. Effective manipulation of soft tissues facilitates highly accurate impressions, superior prosthesis adaptation, and enhanced long-term clinical outcomes. However, soft tissue management remains underutilised in general practice despite its significance. This is largely due to behavioural factors such as clinician hesitation, lack of specialised training, patient discomfort, and time constraints. Overcoming these challenges requires education, advanced techniques, and patient-centred approaches to improve clinical outcomes.

INTRODUCTION

The difficulties that arise from the labial, buccal mucosa and tongue, along with the challenges of accessing and operating instruments, and the positioning of treated teeth concerning the gingival tissues, which can bleed if not properly handled, render the oral cavity a complex area for treatment in prosthetic dentistry[1]. The dental dam usually serves a valuable purpose in operative dentistry and single-tooth restorations by providing field control and facilitating access to tooth preparation and restoration; however, its use is not universal in restorative dentistry. At times, caries or non-carious cervical lesions may be located at or beneath the free margins of the gingiva. In fixed prosthodontics, positioning crown or inlay/onlay margins at or below this margin can complicate preparation, impression, and cementation access. Additional techniques are often required to displace gingival tissues and manage gingival haemorrhages and sulcular fluids effectively[2]. One of the most discerning aspects of crown and bridge procedures is handling the gingival tissues during the impression process[3].

The process of impression making for fixed partial dentures is highly technique-sensitive, as it necessitates an accurate reproduction of the finish lines. Consequently, before obtaining an impression, it is essential to retract the gingival sulcus. Whether using a traditional impression material or a digital technique, the rationale for tissue management plays a crucial role in impression making. This ensures that the impression precisely replicates all margins of the tooth preparation, resulting in a superior marginal fit for a laboratory-made restoration. Once the final restoration aligns with the tooth preparation and undergoes cementation, it aids in preventing recurrent dental decay, tooth sensitivity, and gingival irritation[4]. The mechanical, surgical, or chemical widening of the gingival sulcus pushes gingival tissues surrounding the preparation edges, allowing enough low-viscosity impression material to fill the larger space and preserve the detail of the edges without compromising periodontal health[5].

The three primary goals to achieve an accurate impression are isolation, retraction, and accessibility. The operative site is isolated to ensure a dry and clean operating area, to ensure easy access and clear visibility, enhance properties of dental materials, protect both the patient and the operator, and promote operational efficiency[6]. The critical sulcular width seems to be around 0.2 mm. A width of less than 0.2 mm leads to impressions that are more likely to have voids in the marginal area, an increase in tearing of the impression material, and a decrease in marginal accuracy. Inadequate tissue management can result in enduring damage to soft tissue. The impression must be free of air bubbles, thin spots, and any other imperfections that could lead to inaccuracies[7].

Several studies have found specific factors that influence the outcome of an impression: Tissue health, fluid control, and exposure at the finish line. The purpose of gingival retraction is to gently make it easier for the impression material to reach beyond the edge of the abutment and to make room for enough thickness of impression material in the gingival sulcus area so that it can better withstand the forces used to remove impressions[8-10]. Mechanical, chemical, surgical, and various combinations of these methods are categories into which gingival displacement techniques fall. Most of the operator use a mix of mechanical and chemical methods to move the gingiva back into place. This is done by using gingival retraction cords along with certain hemostatic agents. Practitioners utilize soft tissue lasers and surgical methods, such as rotary gingival curettage and electrosurgery, as supplementary procedures alongside mechanical and chemical techniques[11-13].

CLASSIFICATION OF GINGIVAL TISSUE RETRACTION

Figure 1A shows surgical retraction (gingivectomy and gingivoplasty, periodontal flap procedures, electrosurgery, and rotary gingival curettage), according to Barkmeier and Williams[14]; non-surgical retraction (rubber dam and clamps, retraction cord-impregnated/non-impregnated, retraction rings, and copper bands)[15]. Figure 1B shows the classification of gingival tissue retraction: Conventional and radical. According to Benson et al[16], Figure 1C shows the classification of gingival tissue retraction: (1) Mechanical method: Gingival protector, rubber dam, copper band (or) tube, anatomic retraction caps, retraction cords, and special cords; (2) Chemi-mechanical method: Vasoconstrictors, biological fluid coagulants, and surface layer tissue coagulants; (3) Rotary gingival curettage; and (4) Electrosurgical methods. The goal of gingival retraction is to gently make it easier for the impression material to reach beyond the edge of the abutment and to create space for enough thickness of impression material in the gingival sulcus area so that it can resist pulling forces better when impressions are taken out. The well-structured, fiber-rich periodontal complex around natural teeth supports these gingival tissues during retraction, which keeps these tissues from falling apart when the retraction agents are taken out before the impression is made[3,5].

Figure 1 Classification of gingival tissue retraction. A: The classification of surgical and non-surgical gingival tissue retraction; B: The classification of conventional and radical gingival tissue retraction; C: The classification of gingival tissue retraction methods.

The importance of finish line exposure in prosthodontics: (1) It is a line of demarcation; (2) The peripheral extension of a tooth preparation; (3) The planned junction of two materials; and (4) The terminal portion of the prepared tooth. Gingival tissue must be healthy and free of inflammation before fabricating cast restorations, and this impression must precisely replicate the final result. For optimal marginal fit and to avoid recurring cavities and gingival inflammation, temporarily expose the finish line to reproduce the entire preparation. Obtaining a complete impression is difficult when the preparation’s finish line is at or below the crest of the free gingiva. To ensure complete reproduction of the preparation, temporarily expose the preparation’s finish line. It is important to keep fluids under control in the sulcus, especially when using hydrophobic impression materials[7,8]. Advantages: (1) Provides maximal exposure to the operating site; (2) Better marginal fit; (3) Prevents tissue from trauma; and (4) Helps in better preparation and impression.

Gum protector

This tiny device has a crescent-shaped tip that can be positioned and adjusted to the contours of the gum tissue to protect the gums during procedures near the gum margins[16]. They are helpful for subgingival cavity removal, cavity preparation, finishing veneer margins, and verifying the proper seating of crowns with subgingival margins in Figure 2A[17].

Figure 2 Gum protector and copper band. A: The gingival protector; B: The copper band.

Copper band

This carries the impression material and displays the gingiva to expose the finish line. The band uses either impression compounds or elastomeric materials. The tube is carefully positioned, containing the modelling compound along the tooth preparation path to make an impression[17]. The copper bar is shaped into a tube corresponding to the size of the prepared tooth. One tube end is trimmed to match the profile of the gingival finish line, followed by the positioning and contouring of the tube over the prepared tooth before filling it with the modelling compound as shown in Figure 2B[18]. They are beneficial in situations in which several teeth have been prepared. The disadvantages include copper bands carrying incisional injuries to the gingiva and gingival recession.

Rubber dam

In 1864, New York City dentist S.C. Barnum introduced the rubber dam to dentistry. The rubber dam keeps teeth dry and enhances the quality of restorative dentistry. A rubber dam can also expose the necessary finish line. It is typically used when a few teeth in one quadrant are being restored and when preparations do not need to extend far subgingival. The advantages are a dry, clean operating field, maximum access and visibility of tooth and the margins, improved properties of dental materials, protection of the patient and operator, and operating efficiency. Time consumption and patient objection are the most frequently quoted disadvantages of the rubber dam[19]. The role of the rubber dam in fixed bridge isolation is shown in Figure 3A. Isolating one or more abutment teeth of a fixed bridge is sometimes necessary. The restoration of an adjacent proximal surface and the cervical restoration of an abutment tooth indicate the need for fixed bridge isolation[19,20].

Figure 3 Rubber dam and anatomic retraction cap. A: The role of the rubber dam in fixed bridge isolation; B: The anatomic retraction cap.

The techniques suggested for this procedure are as follows: Punch the rubber dam as usual, but create one large hole for each unit in the bridge. Once the dam is complete, the fixed bridge isolates itself. A curved suture needle with dental floss is threaded from the front through the anterior abutment hole, under the anterior connector, and back through the same hole on the backside[19]. The needle is reversed and passed from the lingual side through the hole of the second bridge unit, under the anterior connector, and through the hole of the second bridge unit on the facial side. A square knot is tied with the floss ends, pulling the dam material tightly around the connector and into the gingival embrasure. Cut the free ends of the floss closely to avoid interfering with access and visibility or getting entangled in a rotating instrument. This method isolates each terminal abutment of the bridge.

If the floss knot on the front interferes with the cervical restoration of an abutment tooth, the operator can tie the septum from the back. To remove the rubber dam from a fixed bridge, cut the interseptal rubber over these connectors with scissors and take out the floss ties[20]. After dam removal, the operator must ensure that no dam segments are missing and should gently manipulate the adjacent gingival tissue. The retainer’s jaws often hinder the correct positioning and wedging of the matrix band on the posterior anchor tooth. The successful application of the matrix can be achieved by replacing the retainer with the matrix[20,21]. The operator’s index finger pushes the rubber dam down on the facial jaw, while the assistant does the same on the lingual side. When the band is placed, the dam inverts around it due to the released tension. The matrix lacks jaws and a bow, which can cause the dam to slip occlusally and over the matrix if dryness is not maintained. The operator gains access and visibility for alloy insertion by using a mirror to reflect the dam distally and occlusally. Care must be taken not to stretch the dam excessively, as this can cause it to detach from the matrix, leading to leakage around the tooth or slippage over the matrix. After condensation, carve the occlusal portion before removing the matrix. The operator can complete the procedure by either: (1) Removing the matrix, replacing the retainer, and finishing the carving; and (2) Removing the matrix and rubber dam and then completing the carving. Replace the retainer before finishing the carving to ensure isolation during this procedure[19-21]. The anatomic retraction cap is shown in Figure 3B. The traction cap works similarly to a copper band, but its shape is pre-designed to simply be placed between the teeth. Once positioned, the patient bites down on the cap. Physical pressure stops the bleeding and opens the groove for the final impression[22].

Retraction cords

Gingival tissue displacement is most commonly achieved using retraction cords, which are available in various forms, including knitted, twisted, and braided. These cords can be impregnated with medicaments or hemostatic agents or left non-impregnated. Since there is no standardised sizing system, clinicians can choose the configuration that best suits their needs. Retraction cords are colour-coded and available in different diameters, typically numbered from 000 to 3, to accommodate various clinical situations and sulcus depths. They can be dispensed in pre-cut lengths corresponding to tooth diameters or from a container or clicker.

Ideal properties of retraction cord

An ideal retraction cord should: (1) Be biocompatible and non-toxic; (2) Absorb blood, crevicular fluids, and medicaments effectively; (3) Be easy to insert and remove; (4) Have a color that contrasts with surrounding tissue; and (5) Avoid causing damage to supporting tissues[23]. Figure 4 shows the types of retraction cords. The indications for different thickness cords are shown in Table 1.

Figure 4  The types of retraction cord.

Table 1 Indications for different thickness cords.

Cord	Indications
000	Anterior teeth
	Double packing
	Substitute for black silk suture as lower cord in the “two-cord”
	technique
00	Preparing and cementing veneers
	Restorative procedures dealing with thin, friable tissues
0	Lower anteriors
	When luting near gingival and subgingival veneers
	Class III, IV and V restorations
	Second cord for “two-cord” technique
1	Tissue control and/or displacement when soaked in coagulative hemostatic solution prior to and/or after crown preparations
	Protective “pre-preparation” cord on anteriors
2	Upper cord for “two-cord” technique
	Tissue control and/or displacement when soaked in coagulative
	Hemostatic solution prior to and/or after crown preparations
	Protective “pre-preparation” cord on anteriors
3	Areas that have fairly thick gingival tissues where a significant amount of force is required
	Upper cord for those desiring the “two-cord” technique

Characteristics of different retraction cords

Braided cords have a tightly woven structure, making them easy to place without fraying, as shown in Figure 5A. They offer excellent absorption when used with medications. However, applying pressure to one section may cause another segment to dislodge from the sulcus. Knitted cords are designed with interlocking loops, which provide flexibility and passive adaptation during placement (Figure 5B). This feature prevents movement when another section is inserted into the sulcus. Knitted cords tend to compress upon insertion, so a slightly thicker size is recommended for optimal stability and tissue displacement. To prevent unravelling, a smooth, non-serrated instrument should be used during placement[24]. Twisted cords have a higher tendency to fray and untwist during placement, making them less commonly used compared to braided and knitted cords in Figure 5C. The Stay-Put retraction cord features a fine central wire, available in both plain and pre-impregnated versions (Figure 5D). Its key advantage is that it maintains its shape after placement. The pliability of the cord allows for easy insertion and pre-shaping. The pre-impregnated version contains aluminium chloride, which minimises cardiovascular risks. Available in four sizes (0-3), it can be used with compression caps in both standard and anatomical shapes. The anatomical compression cap has a semicircular design on the facial and lingual sides that can be placed over neighbouring teeth to enhance traction. After inserting the cord, the compression cap is placed over the tooth, and the patient is then instructed to bite down. This technique further promotes gingival sulcus traction[25].

Figure 5 Characteristics of different retraction cords. A: The braided cord; B: The knitted cord; C: The twisted cord; D: The stay-put retraction cord.

Chemo-mechanical methods

This method uses a traction cord and chemicals or medications. There is a wide variety of materials used with gum retractors. These chemicals can be pre-impregnated into the gingival retractor or soaked into a traditional gingival retractor before insertion[26]. The primary effect of all these chemicals is to stop bleeding and reduce crevicular fluid leakage while physically displacing the gingival tissue[27]. They can be vasoconstrictors that force blood vessels to constrict, astringents that shrink gum tissue, or substances that stop bleeding by hemostasis and clotting. Some of the therapeutic agents are gel or liquid formulations that can be injected directly into the gingival sulcus to stop bleeding and gingival fluid[28-30]. Chemicals used for this purpose can be classified by their actions (Figure 6). The advantages and disadvantages of these chemical agents are shown in Table 2[30].

Figure 6  The chemicals used for tissue retraction.

Table 2 The advantages and disadvantages of different chemical agents.

Chemicals	Advantages	Disadvantages
Epinephrine	Good tissue displacement	Systemic reactions
	Minimal tissue loss	Epinephrine syndrome
	Good hemostasis	Risk of inflammation of the gingival cuff
		Rebound hyperemia
		Risk of tissue necrosis
Alum	Minimal tissue loss	Less hemostasis and tissue displacement
	Extended working time	Offensive taste
		Risk of necrosis if in high concentration
Aluminum chloride	Minimal tissue loss	Local tissue destruction
	Good hemostasis	Less vasoconstriction than epinephrine
	No systemic effects	Risk of sulcus contamination
	Least irritating of all chemicals	Modifies surface detail reproduction
	Hemostasis	Inhibits set of polyvinyl siloxane and polyether impressions
	Little sulcus collapse after cord removal
Ferric sulfate	Compatible with aluminum chloride	Non compatible with epinephrine
		Tissue discoloration
	Good displacement	Acidic taste
		Risk of sulcus contamination Inhibits set of polyvinyl siloxane and polyether impressions
Tannic acid	Good tissue response	Less displacement
		Minimal hemostasis

Cord packing instrument

The retractable cord filler is designed to insert the retractable cord into the gingival sulcus (Figure 7A)[31]. Nevertheless, many medical professionals use a variety of tools for this purpose. It is important that whichever tool is used, its working end must be narrow enough to effectively wind the cord into the sulcus but not so sharp as to cause bleeding or perforation of the wall of the sulcus[32]. The instrument can also be double-ended, with multiple orientations of the working edge, which makes it easier to insert the cable around the tooth without having to change hand positions or tools. This design also eliminates obstructions in the field of view[33,34]. Depending on the operator’s requirements, the working end can be either smooth or serrated. Smooth, rounded end devices are mainly used for packing stranded wire, while serrated end devices are used for braided wire[35]. The serrated ends prevent this cord from slipping during deployment; however, this might cause fraying if not utilised carefully. A periodontal probe can be utilised to pack interproximal cords, as gingival tissues in this location are thin and sensitive. For thin gingival biotypes, a flat plastic instrument can be used to place the retraction cord without injuring the sensitive tissue[36-39].

Figure 7 Instruments. A: The cord-packing instruments; B: The magic foam cord; C: The Expasyl; D: The Merocel; E: The GingiTrac; F: The retraction capsule.

Single cord technique

Isolate prepared teeth with cotton rolls, use saliva evacuators as needed, and dry this field with air. Cut a string long enough to wrap around the tooth. Do not over-desiccate the tooth, as this may cause postoperative sensitivity. Soak the cord in an astringent solution and remove excess with a gauze pad. To prevent the thin sulcular epithelium from sticking and ripping during removal, a wet, impregnated cord should be in place. Twist the non-braided cords tightly for easy placement. Loop the cord around the prepared tooth, forming a “U” shape. Apply low pressure in the apical direction while holding the cord between your thumb and forefinger. Starting at the interproximal area allows for easier placement of the cord compared to the facial or lingual areas. Use a Fischer packing or DE plastic device to gently slip the cord between the tooth and the gingiva in the mesial interproximal area. After tucking the cord into the mesial, use this device to lightly fasten it in the distal interproximal area. Start with the lingual surface and work from the mesiolingual corner to the distolingual corner. Move the instrument slightly toward the cord-placed location (mesial). If the instrument tip is angled away from where the cord is put, it may be dislodged and pulled out. For a shallow sulcus or finish line with shifting shapes, use a Gregg 4-5 device in the left hand to keep the cord in place[40].

To place the cord, use the packing instrument in the right hand. Use the instrument to gently press the cord apically, directing the tip slightly towards the tooth. Gently slide the cord along the preparation to the finish line. Then, push the cord into the crevice. If the instrument is aimed completely apically, the cord will bounce off the gingiva and roll out of the sulcus. If the cord continues to rebound from a narrow location of the sulcus, do not apply more force. Instead, keep a mild force for a longer duration. If the cord still rebounds, use a smaller or more malleable cord (twisted rather than braided). Secure the cord at the mesial, where it was previously lightly tacked. Cut the length of the cord extending from the mesial sulcus as close as feasible to the interdental papilla. Pack the cord around the facial surface and overlay it in the mesial interproximal area. Overlap should always be in the proximal area, where the tissue can support the excess cord. If this overlap occurs on the facial or lingual surface where the gingival is tight, there will be a gap apical to the crossing, and the finish line may not be repeated in the impression. Pack everything except the last 2.0 mm or 3.0 mm of cord. The tag is left projecting so that it can be easily gripped and removed. Tissue retraction should be forceful but gentle, ensuring the cord rests at the finish line. Do not overpack. Place a generous amount of gauze in the patient’s mouth. This will make the patient more comfortable by providing something to close on while also keeping the area dry. After 10 minutes, cautiously remove the cord to prevent bleeding. Inject the impression material only if the sulcus is clean and dry. Gently remove any coagulum. Then, lightly blow air onto it. If bleeding persists, stop the impression-making procedure[40].

Double cord technique

First, a thin cord is put in and trimmed so that the ends do not overlap. A second, bigger cord is then put in and removed as usual. The thin first cord persists during the impression-making process. When incorporating this approach, clinicians should avoid damaging the epithelial connection[41].

Cord positioning force

Inserting the cord into the gingival sulcus requires non-damaging minimal force; otherwise, the displacement operation can result in bleeding and damage to the sulcular and junctional epithelium. Inadequate use of force during cord insertion might cause gingival recession later on due to disruption in blood flow and injury to the periodontal attachment fibres. When tucking the cord in the sulcus, considerable force may be used unintentionally, especially if the patient is anaesthetized. According to Phatale et al[22], the epithelial attachment sustains damage at 1 N/mm and ruptures at 2.5 N/mm, which is nearly the same force required to place the retraction cord[42].

Cord retraction time

The time the cord is placed in the gingival sulcus is also critical. If the cord is not inserted long enough, the gingival tissue may not be displaced sufficiently for the impression material to document the subgingival preparation margin. If the wire is left in place for only two minutes, the width of the gingival sulcus will be reduced to 0.1 mm within 20 seconds of removal. However, if the retractor is left in place for too long, it may lead to gum tissue damage and gingival recession. This is especially true for pre-impregnated retractors or retractors treated with hemostatic chemicals. Floss left in the gingival sulcus for an extended time may dry out. If this occurs, it can stick to the surface of the gingival sulcus and tear the surface of the gingival sulcus when removed. According to several studies, the optimal time is 1 minute to 30 minutes. The goal should be to secure the cord in the sulcus in as short a time as possible, minimising damage to the delicate soft tissues. This may be easy for single tooth preparations, but for multiple tooth preparations, it is critical to keep track of the amount of time the cord is placed on the previously prepared teeth. If it takes too long to prepare successive teeth, the cord should be removed and re-wrapped after treatment is complete. In addition, the gingival sulcus of all prepared teeth should be evaluated after the impression is taken to ensure that there are no accidental cord fragments left in the gingival sulcus[42,43].

Infusion technique

After carefully preparing cervical margins at intra-crevicular placements, bleeding is controlled with a specially designed dento-infusor containing ferric sulfate. There are two concentrations of ferric sulfate available: 15% and 20%. The 20% material is preferred over the 15% solution because it is less acidic and does not remove the smeared layer of dentin from the prepared tooth. Using a burnishing motion, the infusor is manipulated around the gingival sulcus and carried from the syringe. Once hemostasis is confirmed, a knitted retraction cord is soaked in ferric sulfate solution and inserted into the sulcus. After removing the cord and rinsing the sulcus with water, an impression is created. When using the single cord approach, the dento-infusor and 20% ferric sulfate are useful supplementary techniques for haemorrhage management. Even with a cautious procedure, isolated pockets of bleeding may occur when the cord is removed from the sulcus. In such cases, the infusion and medicament can be applied to the sulcus with hard burnishing pressure for around 15 seconds. When incorporating ferric sulfate materials, patients should be aware that their tissues may temporarily discolor. The tissues take on a blue-black hue that normally fades within a few days[41-43].

Every other tooth technique

When taking an impression of anterior teeth preparation, no damage must be done to the gingival tissues, which may result in tooth recession with root proximity; placing a retraction cord simultaneously around all prepared teeth may result in strangulation of the gingival papillae and eventual loss of the papillae. This produces unappealing black triangles in gingival embrasures. This unpleasant effect can be avoided with the “every other tooth” approach. Retraction operations are performed on anterior teeth. If teeth 5-12 are prepared, cords will be inserted around teeth 5, 7, 9, and 11. The impression is made, gingival displacement is performed on teeth 6, 8, 10, and 12, and a broad impression is created. A further pick-up impression allows the creation of a master cast, including dies for all eight prepared teeth[43].

Magic foam cord

Developed by Professor Dr. Dumfahrt, Magic foam cord is a non-hemostatic gingival retraction system manufactured by Coltène/Whaledent (Figure 7B). Made from polyvinyl siloxane, this material expands within the gingival sulcus, aiding in tissue displacement. It is used alongside a compression cap, which the patient bites down on before removal. The degree of retraction is then assessed, and if satisfactory, the final impression is taken. The system includes components such as foam, cartridges, mixing tools, intraoral tips, and Comprecaps[44].

Expasyl

Introduced by Satelec Pierre Rolland and marketed as Cordless Gingival Retraction (SDS/Kerr Company), Expasyl is a viscous synthetic slurry containing 10% aluminium chloride, 80% kaolin, water and modifiers (Figure 7C). When injected into the sulcus, it exerts gentle pressure without causing damage to the gingival tissues. The small cannula tip allows for precise placement, making the process faster and less traumatic for the patient. However, the high aluminium chloride concentration has been linked to tissue necrosis and sensitivity[45].

Merocel

Developed in 1996 by Ferrari et al[30], Merocel is a synthetic polymer cut into 2 mm sponge-like strips (Figure 7D). It is derived from hydroxylated polyvinyl acetate, a biocompatible material that absorbs fluids and expands within the gingival sulcus. After removal, it exposes the finish line, allowing for impression-taking. Besides dental applications, Merocel is also used in ear, nose, and throat, gastric, and otoneurosurgical procedures[46].

GingiTrac

GingiTrac is a mild natural astringent gel (Figure 7E), used alongside foam cylinders, which are available in two sizes: Regular and Large. The procedure involves placing a polyvinyl siloxane paste into the gingival sulcus and instructing the patient to bite down for 3-5 minutes to allow the material to set. The assembly is then removed, and the retraction level is evaluated. If the sulcus is adequately retracted, the final impression is made; otherwise, the process is repeated. This technique is minimally invasive and gentle on gingival tissues[45,46].

Retraction capsule

The retraction capsule (Figure 7F) contains a high-viscosity astringent paste with 15% aluminium chloride, designed for use with a composite capsule dispenser. It features a long, slender nozzle with a soft edge, allowing precise delivery into the gingival sulcus. Additionally, a white orientation ring on the nozzle matches the size and position of a periodontal probe, preventing excessive insertion and ensuring controlled application[47].

Rotary curettage or gingettage

In 1954, Amsterdam described the idea of rotary curettage. A torpedo-tipped diamond forms a chamfer finish line while also removing the sulcus’ epithelial lining. It is a troughing procedure used to remove a minimal amount of epithelial tissue in the sulcus while creating a chamfer finish line in tooth size. The method known as “gingettage” is used for subgingival placement of restorative margins. Before rotary curettage, a shoulder is developed at the gingival crest. Rotational curettage should only be performed on healthy, inflammation-free tissue to minimise tissue shrinkage that occurs when diseased tissue heals. The following parameters must be met for gingettage: (1) The absence of blood when probing the gingiva; (2) The depth of the sulcus is less than 3 mm; and (3) The presence of sufficient keratinied gingiva[48].

Electro-cautery or electro-surgical retraction

Electrosurgery refers to the considerable reduction of sulcular epithelium achieved with the use of an electrode to cause gingival retraction. It is a high-frequency radio transmitter that employs a vacuum tube or a transmitter to produce an electrical current of at least 1.0 MHz (one million cycles per second). The surgery is also known as surgical diathermy[48,49].

Lasers in gingival retraction

Recent advancements in dentistry have facilitated the use of lasers for hemostasis and soft tissue removal before impression-taking. By eliminating tissue within the gingival sulcus, lasers allow for a clear view of the preparation margins, enabling highly accurate impressions. While diode lasers are the most commonly used for this purpose, neodymium-doped yttrium aluminium garnet (Nd: YAG) and erbium-doped yttrium aluminium garnet (Er: YAG) lasers are also effective. Studies indicate that laser-assisted gingival retraction is less painful and, in some cases, can even be performed without anaesthesia[48]. Additionally, lasers minimise postoperative pain, bleeding, and gingival recession. However, they come with higher operational costs and require more time for tissue removal compared to electrocautery or a scalpel. Despite these limitations, lasers are widely employed for tissue contouring procedures[49].

Retraction around implants

The soft tissue surrounding implants differs significantly from that around natural teeth. Peri-implant tissues have weaker adherence, greater permeability, and lower regenerative capacity. As a result, they are more prone to damage and recession when subjected to retraction techniques. Furthermore, these tissues naturally tend to retract even after retraction procedures, making impression-taking particularly challenging, especially for deeply placed implants. Comparing different retraction techniques, research suggests that retraction cords may cause excessive trauma to the delicate peri-implant tissues. Instead, chemical retraction agents - such as 15% aluminium chloride in an injectable kaolin matrix - are preferable, as they cause minimal damage to the junctional epithelium. However, their effectiveness decreases when working with subgingival margins[49]. From a surgical standpoint, Nd: YAG lasers are not recommended near implants since their wavelength can overheat the implant, leading to bone damage. In contrast, the Er: YAG laser is safer because its energy is reflected by metal surfaces, but it is less effective for hemostasis compared to the CO₂ laser. Electrosurgery is also unpopular due to the risk of osteonecrosis and arcing through metal implants. Additionally, rotary curettage should be avoided, as limited tactile control may result in unintentional damage to the implant’s surface. The absence of keratinized gingiva in peri-implant areas further increases the risk of tissue recession if rotary curettage is attempted[49,50].

Retraction for digital impressions

One major challenge with traditional visual impressions is the restricted line of sight, which can limit accuracy. In digital computer-aided design and computer-aided manufacturing impressions, maintaining a clear sulcus is crucial. Residual retraction cord fibres within the sulcus may compromise gingival retraction accuracy, leading to artifacts and errors in the digital impression. A 15% aluminium chloride injectable matrix is often preferred because it leaves the sulcus clean upon removal, reducing the risk of artifacts. While indirect data capture is generally considered more precise, its accuracy is influenced by the thickness of the impression material within the sulcus. If the impression margins are too narrow, especially if their radius is smaller than the contacting probe tip, this can result in significant inaccuracies[51].

CONCLUSION

As gingival traction is an essential element of clinical practice, clinicians should make every effort to use the many procedures and products of gingival tissue traction in a variety of clinical situations. Sometimes, a variety of methods is required, and certain things may work for a particular practitioner but not for another. The effort placed into proper gingival tissue retraction pays significantly in terms of restoration lifespan, margin improvement, and aesthetics.