|Year : 2019 | Volume
| Issue : 4 | Page : 185-188
Recent advances on gingival tissue management in restorative dentistry
Pavitra Sampath1, Lavanya Varma1, Manoj Varma2, Aneesh Shabu1
1 Department of Conservative Dentistry and Endodontics, Srinivas Institute of Dental Sciences, Mangalore, Karnataka, India
2 Department of Prosthodontics, Srinivas Institute of Dental Sciences, Mangalore, Karnataka, India
|Date of Submission||23-May-2019|
|Date of Decision||22-Jul-2019|
|Date of Acceptance||22-Jul-2019|
|Date of Web Publication||1-Oct-2019|
Department of Conservative Dentistry and Endodontics, Srinivas Institute of Dental Sciences, Mangalore, Karnataka
Source of Support: None, Conflict of Interest: None
An increased emphasis on the perio–restorative interface in restorative dentistry is important to enable the utilization of the concept of biologic width in a practical manner. Regarding management of gingival tissues, the goal is to ensure that the peridontium is in a healthy state. As the oral cavity is a difficult-to-treat area because of the hindrance of lips, cheeks, and tongue, it becomes difficult to visualize and manipulate instruments in the area to be treated related to the gingival tissue which bleeds if improperly managed.The aim of this review is to describe the four categories of biological width and provide the clinician with an overview of gingival retraction techniques available for clinical situations that are frequently encountered.
Keywords: Biological width, hemostasis, retraction, tissue management
|How to cite this article:|
Sampath P, Varma L, Varma M, Shabu A. Recent advances on gingival tissue management in restorative dentistry. Indian J Dent Sci 2019;11:185-8
|How to cite this URL:|
Sampath P, Varma L, Varma M, Shabu A. Recent advances on gingival tissue management in restorative dentistry. Indian J Dent Sci [serial online] 2019 [cited 2019 Nov 19];11:185-8. Available from: http://www.ijds.in/text.asp?2019/11/4/185/268419
| Introduction|| |
The oral orifice being a partially confined space poses a number of challenges to the clinician, especially in the field of restorative dentistry. The lack of proper access and means to visualize the operating area is the foremost factor that hinders a wholesome restorative procedure. Hence, in order to tackle these physical limitations, a number of methods and practices have been brought about, over the years. The focus of this article would be on those techniques that concern the gingival isolation and retraction methods that would be advantageous (but not exclusive) to restorative dentistry keeping in mind the concept of biologic width.
Occasionally, a carious or noncarious, Class V lesion would be seen on the gingival third of the tooth, that is, below the free gingival margin. Similar situations arise in fixed prosthodontics, where inlays or onlays are at or below the level of the free gingival margin. Both the aforementioned situations require special gingival tissue management for preparation, impressioning, and restoration. These gingival management methods encompass ways to displace the gingival tissue and to control gingival hemorrhage.
During the 1970s, due to a misinterpretation of the definition of biological width, for over four decades, it was mistaken to be an absolute value rather than an arithmetic mean. Because of this, it was impossible to explain why different patients receiving crowns would have different gingival reactions.
| Categories of Biological Width|| |
Kois published his definitive articles on biological width in the mid-1990s. In these articles, he suggested that the restorative dentist must determine the total distance between the gingival crest and the alveolar crest. This procedure is called bone sounding. This procedure is carried out by anesthetizing the patient and placing a periodontal probe on the sulcus, and it is then pushed deeper into the attachment apparatus until the tip engages the alveolar bone. He proposed three categories of biological width based on the total dimension of attachment and the depth of the sulcus. Based on the measurement, the three categories of biological width are the normal crest, high crest, and low crest [Figure 1].,
|Figure 1: (a) The normal crest, (b) the high crest, (c) the low crest, and (d) the subclassifications of the low crest. Source: Courtesy of William J Robbins|
Click here to view
This category comprises those patients that have a midfacial measurement of 3.0 mm and a proximal measurement of 4.5 mm. It is theorized that a crown's margin is best placed no closer than 2.5 mm from the alveolar bone. Hence, accordingly, a crown margin placed 0.5 mm subgingivally will be tolerated well in the long run.
In this category, the midfacial measurement is <3.0 mm, whereas the proximal measurement is also <3.0 mm. This is a rare finding and occurs only in 2% of the population. Here, it is not possible to place an intracrevicular margin as it will be too close to the alveolar bone leading to chronic inflammation and biological width impingement. A high-crest situation can occur if the interproximal papilla is not supported, and it collapses following an extraction.
In this category, the midfacial measurement is >3.0 mm, whereas the proximal measurement is >4.5 mm. In such a situation, patients are more prone to recession following the placement of an intracrevicular crown margin.
Low crest, stable or unstable
The low-crest attachment is more complex as not every patient responds the same to an injury to the attachment apparatus. The difference lies in the depth of the sulcus which can have a wider range. Hence, the low-crest attachment is further divided into stable and unstable attachments. To diagnose a patient as stable or unstable, sulcus probing as well as bone sounding has to be done.
| Techniques for Soft-Tissue Management, Displacement, Retraction, and Hemorrhage Control|| |
Mechanical displacement techniques are one of the earliest gingival retraction techniques, particularly for crown and bridge impressions. This method refers to the process of physically keeping the gingival tissue away from the preparation site for improved access and visualization. Among the first mechanical retraction methods was the use of rubber dam. Gingival clamps specifically made for this purpose were used to allow better access and visualization by displacing the tissues.
Using gingival cords is one of the most popularly used mechanical retraction methods. There are different types of gingival retraction cords available such as those that are woven, braided, or twisted in various configurations suitable for different diameters and thicknesses. They are usually dispensed from containers, out of which the required length is cut out. There are also containers with self-cutting dispensing boxes. However, none of these containers address the problem of cutting out excess or a little less than what is actually needed of the gingival cord. This can make it harder to manage the retraction process. Hence, to tackle this problem, Short Cut by DUX Dental System came up with a dispensing unit that has a wheel that pushes out a specific length of the cord with each click. In general, 3–4 clicks provide a length of a braided cord for an anterior tooth, whereas it is 4–5 for premolars and 5–6 clicks for molars. It is available as nonimpregnated so that the clinician can choose the type of astringent or hemostatic agent to be used. A lot of clinicians choose braided over other cord types as they are tighter and have a more consistent weave pattern.
Knitted cords have the benefit of minimizing fraying and unraveling during cord placement. They expand when wet and open up the sulcus to a size more than the actual diameter of the cord. While using knitted cords, a smooth, nonserrated placement instrument can be used for better placement of the cord without displacing it out of the sulcus. An important point to remember while placing the cord is that the end of the packer should be thin enough to be placed in the sulcus while not causing any damage to the gingival tissue or induce bleeding. The angle of the instrument should allow for orientation so that the cord can be placed around all surfaces of the tooth. A recent breakthrough in cord placement instruments was the introduction of a dual-packing blade (TN010 Double Cord Packer, Garrison Dental Solutions, Spring Lake, Michigan, USA).
For knitted cords, smooth cord-packing instruments are less likely to displace the cord from the sulcus while placing, whereas for twisted and braided cords, both serrated and smooth cord packers work well. For improved gingival retraction using cords, the use of a double-cord technique would be advisable, wherein a thin diameter cord is placed at the base of the gingival sulcus without any overlap. The cord is maintained during the impression to control gingival bleeding. A second wider diameter cord is placed on the top of the first cord to accomplish tissue displacement. However, before recording the impression, the cord needs to be made wet so as to avoid gingival damage. The cord is removed, and the impression is made while the first cord is intact.
Another mechanical displacement method is the use of copper tubes. They serve as a means of recording the impression as well as displacing the gingival tissue in order to ensure that the gingival finish line is captured in the impression. In this method, the impression is taken at the same time. First of all, the copper band needs to be cut to shape, contoured, and fitted beyond the crown preparation margin. Now, this is filled with an elastomeric impression material, compound, or a combination of acrylic resin, and then relined with a rubber base in order to displace the gingival tissue and record the impression at the same time. It is particularly useful in the cases of multiple preparations recorded in an elastomeric impression and a localized impression defect has occurred. The use of copper tubes can nullify the need to make an entire full-arch impression for a single-tooth preparation.
Because the importance of astringents and hemostats on gingival retraction agents has not been lost on the clinician, a number of cords come coupled with gels or coatings. In most cases, the drugs used would be both astringents and hemostats as they work by causing contraction–retraction of the gingival tissues and hemostasis by constricting blood flow through coagulation. The most commonly used astringent–hemostatic agents are ferric sulfate, aluminum chloride, and racemic epinephrine. Chemically impregnated cords have the advantage of offering greater sulcus displacement with combined physical and chemical effects. A 20%–25% aluminum chloride and 15.5%–20% ferric sulfate are the most commonly used chemical reagents. For minimal damage, they should not be used for more than 10 min. It has been reported that epinephrine-impregnated cords need to be used with care as they can elevate blood pressure and cause tachycardia, especially if the gingival tissue is bleeding due to a laceration. There is also a concern that if the use of these solutions goes beyond the crown preparation, then it can lead to postoperative sensitivity. This is because the solutions used in these astringents and hemostats are acidic in nature and cause the removal of the smear layer, which eventually results in sensitivity.
This method is known to provide excellent hemostasis and gingival retraction. Retrac (Centrix Based on Shelton, Connecticut, USA) was the first-generation cordless retraction and tissue management material. Then came GingiTrac (Centrix) that was released as an improvement upon Retrac. In GingiTrac, a heavy viscosity matrix combined with a light body retraction and hemostat paste for single- and multiple-tooth preparations was used. Another material that provides excellent hemostasis is Expasyl (Kerr, Kraemer Blvd, Building E2 Brea, California, USA). Even though it provides excellent hemostasis, the gingival retraction is minimal even when placed directly into the gingival sulcus. Polyvinyl siloxane (Magic Foam Cord, Coltene-Whaledent, Cuyahoga Falls, Ohio, USA) not only provides hemostasis but also, when used with a compression cap, expands the gingival sulcus to allow for easy access for impression making. GingiTrac and Magic Foam are more commonly used impression techniques. Expasyl can be used during routine restorative procedures for impression making and hemostasis.
These cordless techniques ensure nontraumatic, noninvasive tissue management of the sulcus for fixed prosthodontics impressions. These materials and techniques can be used individually or in combination with the use of a gingival cord, electrosurgery, or laser tissue sculpting, when bleeding is difficult to control.
The surgical method for retraction and exposure of the margins of tooth preparation has been referred to as “troughing” or “tissue dilatation.” Currently, the trough, soft-tissue excision, extends from the height of the free margin of the gingiva to a point 0.3–0.4 mm apical to the finish line margin of the tooth preparation. Unlike other methods that provide gingival displacement, the surgical method removes gingival tissues and thus would require soft-tissue healing.
There are different types of surgical gingival tissue management. Rotary curettage is one of these methods. In this type of surgical gingival tissue management, burs are used to create a trough in the sulcus around the finish line. It requires local anesthesia to prevent patients from experiencing discomfort and can result in bleeding at the site. This method can be used for both direct and indirect types of restorations.
Another type of surgical involvement is the electrosurgery. It is a modified cautery technique, utilizing an electric current passed to fine wire contacts that removes soft tissue and creates a trough in the gingival sulcus adjacent to the finish line. This method also requires local anesthesia. However, one of the most important effects of this method is that after the procedure, there is no bleeding. With adequate clinical expertise, this method offers predictable troughing and tissue responses with good exposure of margins for recording impressions and for other restorative techniques.
The traditional surgical approach of using a surgical scalpel for the removal of gingiva has the disadvantage of eliciting bleeding, especially if it is to be followed by a restorative procedure. This is one of the major reasons why restorative dentists prefer electrosurgery over the traditional scalpel-based surgery. However, the heat generated in this type of surgery can cause irreversible damage to the alveolar crest, which can lead to recession and exposure of restorative margins, which, in turn, can compromise the esthetical quality of the preparation.
Just 2 years since their inception in 1958, lasers have been used in the medical field and soon enough in clinical dentistry too. Moreover, their use has increased over the years not only in the medical field but also in dentistry. There are different types of lasers used and based on power, they can be classified as:
- High-power lasers (hard, hot): These are too powerful and can cause necrosis, denaturation, and coagulation
- Intermediate-power lasers: They are far less hot than high-power lasers and thus can help in reducing the treatment time
- Low-power lasers (soft, cold): These have the least or no thermal effects on the tissues and work by the process of photobiostimulation.
Soft-tissue lasers can control moisture and facilitate hemostasis. These abilities are of particular interest to clinicians who have to deal with gingival tissue management, especially while performing esthetic crown lengthening, gingival tissue excision, and troughing. Even though soft-tissue lasers have not yet fully penetrated the entirety of the dental community, they do offer the potential to enhance gingival procedures while exhibiting decreased biological side effects.
Gingival tissue removal for restorative purposes is usually performed in order to gain access and visualization to areas below the free gingival margin. Soft-tissue lasers offer increased control and minimal tissue damage to the adjacent areas. Diode lasers operate at a wavelength that is easily absorbable by the gingiva but pose no harm to the tooth structure.
Diode lasers have the unique specialty of having little to almost no affinity to dental hard tissues, metal alloys, or porcelain, and thus they are suitable for use in close proximity to root surfaces or existing restorations and implants. The effects of laser on cementum are insignificant, and there needs no concern of electricity running through the tooth structure or existing metal restorations.
Exposure of subgingival finish lines while also providing adequate moisture control is a prerequisite for the achievement of precise impressions. Diode lasers provide clinicians with the potential of using a resective technique for gingival troughing which simplifies the impression procedure while also providing proper hemostasis and improved control of heat transfer to adjacent tissues. If done skillfully and alveolar injury is avoided, then the regeneration of the dento-gingival complex can lead to a preoperative or near-preoperative gingival margin levels.
| Conclusion|| |
Clinical success in restorative dentistry is based on the execution of a number of procedures, one of which is isolation, more specifically gingival tissue management. Building and maintaining periodontal health in the restorative-gingival region is very important for the health of the tooth as well as the prognosis of the treatment. Even though constant innovations have been brought about in the field of gingival tissue management over the years, need still arises for new advancements in gingival isolation as well as the betterment of the existing methods. Some of the new advancements mentioned in this article if properly and popularly used can greatly improve the overall quality of restorative procedures by improving the effectiveness of gingival isolation.
The author would like to thank Dr. J William Robbins, for the figures (used with prior permission).
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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