|Year : 2019 | Volume
| Issue : 2 | Page : 51-58
A comparative evaluation of two contemporary cordless methods of gingival retraction – An In vivo study
Abhinav Agarwal, Manesh Lahori, Shilpa Arora
Department of Prosthodontics, KD Dental College and Hospital, Mathura, Uttar Pradesh, India
|Date of Web Publication||30-Sep-2019|
Dr. Abhinav Agarwal
Department of Prosthodontics, KD Dental College and Hospital, Mathura, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim: The aim of this study was to compare and evaluate two different cordless methods of gingival retraction. Materials and Methods: For this study, a total of 30 participants aged above 18 years were selected. Out of 30 patients, 15 patients required fixed prosthesis in the anterior arch and 15 patients required fixed prosthesis in the posterior arch with minimum of two abutments surrounded by healthy periodontium, respectively. Same abutments were used for both retraction systems. After tooth preparation, three impressions for each patient were made, one without retraction, second after application of less viscous syringeable retraction paste, and third after 7 days after application of more viscous retraction paste with applicator gun. This was followed by fabrication of definitive Type IV gypsum cast. Undamaged retrieved casts were sawed out, buccolingually with the help of die cutting saw followed by measurement of the width of the retracted gingival sulcus under a stereomicroscope. The width was measured as the distance from the abutment tooth to the crest of the free gingiva. Results: The mean horizontal retraction attained from the control and two gingival retraction systems was compared using one-way ANOVA with the level of significance (P) set at 0.05. Amount of mean horizontal gingival retraction attained by syringeable retraction system was higher than control but statistically not significant in the anterior segment, whereas in the posterior segment, it was statistically significant.
Keywords: Applicator gun, gingival retraction, syringeable retraction paste
|How to cite this article:|
Agarwal A, Lahori M, Arora S. A comparative evaluation of two contemporary cordless methods of gingival retraction – An In vivo study. J Interdiscip Dentistry 2019;9:51-8
|How to cite this URL:|
Agarwal A, Lahori M, Arora S. A comparative evaluation of two contemporary cordless methods of gingival retraction – An In vivo study. J Interdiscip Dentistry [serial online] 2019 [cited 2019 Dec 16];9:51-8. Available from: http://www.jidonline.com/text.asp?2019/9/2/51/268376
| Clinical Relevance to Interdisciplinary Dentistry|| |
Application of less viscous syringeable retraction system (dryz) was easier to place and found be more comfortable to the patients compared to more viscous expasyl retraction system; however, Selection of gingival retraction system should be based on the clinical situation and the individual clinician's preference.
| Introduction|| |
Marginal integrity is one of the important factors which contribute to the success of cast restorations. The restoration will survive in the biological environment of the oral cavity, only if the margins are closely adapted to the finish line of the preparation.
The prerequisite for making impressions for fixed prosthesis requires the gingival tissues to be displaced to expose the finish lines on the prepared teeth to achieve desirable emergence profile. The procedure to expose the subgingival finish lines of preparation may be termed as gingival displacement, also referred as gingival retraction and gingival deflection. Retraction is the temporary displacement of gingival tissue away from prepared teeth.
Among all the other elastomeric impression materials, the most commonly used impression material is polyvinyl siloxane. The popularity of polyvinyl siloxane impression material is attributed to several characteristics including the dimensional stability, dimensional accuracy, and excellent elastic recovery, ease of manipulation, superior electroplating qualities, and good shelf-life. Apart from the above-mentioned advantages, the polyvinyl siloxane impression materials have few serious limitations. Due to their extremely hydrophobic nature, there should not be any moisture in the gingival crevice, and it is most difficult to pour the cast.
An effective management of the sulcular environment is needed for successful subgingival impression. It involves two key aspects: the force that comes to bear the gingival tissues and contaminants that may be present or generated in the sulcus. Gingival retraction, hemostasis, and sulcular cleansing are frequently combined and closely related procedures. One of the most used methods to obtain gingival retraction is by means of cords packed into the sulcus. Nonmedicated cords placed in the gingival sulcus are safe but have limited effect in controlling hemorrhage. Medicated cords for retraction are effective; however, various studies in the past have shown local and systemic side effects induced by medicaments used for gingival retraction. Apart from being time-consuming, the use of traditional retraction cord may cause discomfort and potential damage to periodontium if used carelessly.
Due to shortcomings of conventional cord, the development of cordless retraction materials is becoming popular. A cordless retraction material is in the form of a paste-like material and is supplied with a specialized metal dispenser. It displaces gingiva by means of its high viscosity when injected into the sulcus. In this study, two cordless retraction systems (Dryz and Expasyl) are being used for gingival retraction.
The purpose of this study is to compare and evaluate the efficacy of these two cordless gingival retraction systems based on the amount of gingival retraction.
| Materials and Methods|| |
A total of 30 patients aged above 18 years were selected. Out of thirty patients, 15 patients required fixed prosthesis in the anterior arch and 15 patients required fixed prosthesis in the posterior arch with minimum of two abutments surrounded by healthy periodontium, respectively. Same abutments were used for both retraction systems after an interval of 7 days.
Patient aged >18 years with healthy gingiva and clinically and radiographically sound two abutments either in the anterior or posterior segment were included in the study.
Patients with unhealthy abutments, periodontitis, uncontrolled diabetes, hypertension, hyperthyroidism, and other cardiovascular disorders were not included in the study.
Preparation of patient
Patients were assessed clinically and radiographically for the sound condition of the abutment. Abutments were prepared for full veneer restoration with subgingival margins taking care to avoid damage to surrounding gingival tissues. After the preparation of teeth, the area was isolated thoroughly.
Two different methods of gingival displacement were used, namely, less viscous syringeable retraction paste (Dryz gingival retraction system, Parkell Inc., USA) [Figure 1] and more viscous retraction system with applicator gun (Expasyl gingival retraction system, Pierre Rolland, Acteon, France) [Figure 2].
Method of application
Syringeable retraction paste (Dryz)
After tooth preparation, the sulcus was rinsed with water and dried with compressed air at an angle. This was followed by expressing Dryz around the tooth into the gingival sulcus until it was covered with material [Figure 3]. Care was taken not to force needle tip into tissues. The material was placed in the sulcus for 2 min after which it was rinsed with water and remaining material was removed using a noncutting hand instrument or cotton pledget. The sulcus was rinsed and dried again, thus making it ready for impression.
Viscous retraction system (Expasyl)
The prepared tooth was rinsed and dried. The Expasyl retraction paste was injected slowly into the gingival sulcus, with the help of an applicator gun cannula in such a way that a closed space was maintained between the tooth and marginal edge of the gingiva. The paste was left in place for 1–2 min and was removed once it had a dry and compact appearance under air and water spray [Figure 4].
Making impressions and obtaining casts
Three impressions were made for each participant with soft putty and light body polyvinyl siloxane impression material (3M ESPE) [Figure 5]: One without gingival displacement and the two after gingival displacement at an interval of 7 days using two different retraction systems. During this interval, patient was given provisional prosthesis.
A total of 90 impressions were made which were divided into two categories: (1) Impressions obtained from anterior segment and (2) Impressions obtained from posterior segment. Each category was further divided into three groups: Group 1 – Impressions without retraction (control), Group 2 – Impressions after retraction with syringeable retraction paste, and Group 3 – Impressions after retraction with viscous retraction system [Figure 6].
Die stone (Kalabhai) models thus obtained during all these intervals were sectioned labiolingually [Figure 7] with the help of electronic die cutting saw (Averon lab cutting device).
Recording sulcular width
The amount of gingival displacement was measured as the distance from the tooth to the crest of gingiva in the horizontal plane under stereomicroscope (SZMCTV1/2 Spectro lab equipment) using an image analysis software (De Winter image analysis software). The image analysis measurements were in micrometer scale, which was later converted into millimeter grading. The amount of retraction was calculated by subtracting the measured width before retraction from the one which was obtained after retraction [Figure 8] and [Figure 9].
| Results|| |
The mean horizontal retraction attained from the control and two gingival retraction systems was compared using one-way ANOVA with the level of significance (P) set at 0.05. As two retraction systems were used on a patient, post hoc analysis was conducted to find out if there exists a significant difference between control and viscous retraction system; control and syringeable retraction paste or between syringeable retraction paste and viscous retraction system (P = 0.05).
Mean value obtained for control was 0.751 mm, and for syringeable retraction paste and viscous retraction system, gingival retraction systems were 0.804 mm and 0.857 mm, respectively, with relation to horizontal retraction in the anterior segment [Table 1] and [Graph 1].
|Table 1: Mean values obtained from control group and two gingival retraction systems after horizontal retraction in anterior segment|
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According to one-way ANOVA, there were no significant differences (P = 0.05) among two retraction systems in anterior segment for horizontal retraction. However, when set of two retraction systems or control and any retraction system were compared with each other using post hoc analysis test, no significant difference (P = 0.05) was found between control and syringeable retraction paste (0.316) and between syringeable retraction paste and viscous retraction system (0.322) in anterior segment. Significant differences (P = 0.05) were found between control and viscous retraction system (0.048) [Table 2] and [Table 3].
|Table 2: Summary of ANOVA tests to determine significant differences between two gingival retraction systems in anterior segment|
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|Table 3: Summary of multiple comparisons tests (honestly significantly different) to determine significant differences between any two gingival retraction systems in anterior segment|
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Mean value obtained for control was 0.888 mm, and for syringeable retraction paste and viscous retraction systems were 0.949 mm and 0.979 mm, respectively, with relation to horizontal retraction in posterior segment [Table 4], [Table 5],[Table 6] and [Graph 2].
|Table 4: Mean values obtained from different gingival retraction systems after horizontal retraction in posterior segment|
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|Table 5: Summary of ANOVA tests to determine significant differences between two different gingival retraction systems in posterior segment|
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|Table 6: Summary of multiple comparisons tests (honestly significantly different) to determine significant differences between any two gingival retraction systems in posterior segment|
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| Discussion|| |
Success of fixed partial dentures is largely dependent on the long-term health and stability of the surrounding periodontal structures. Full coverage preparations often require subgingival margins because of caries, existing restorations, esthetic demands, or the need for additional retention. Marginal integrity is one of the most basic criteria of the principles of tooth preparation. The placement of margin or finish line in relation to the gingival margin has direct bearing on fabrication of restoration and health of the periodontal tissue of the prepared abutment teeth. From the periodontal point of view, it is preferable to place the gingival finish lines of restoration supragingivally or equigingivally. For esthetics or other reason such as caries, existing restoration, and need for additional retention, the dentist may place them subgingivally.
In such situations, the clinician must make impressions that accurately capture the prepared cervical finish lines and permit the fabrication of accurate dies on which the restorations are fabricated. The elastomeric impression materials are popular due to their high degree of accuracy in registering details. However, there may be clinical situations when the cervical finish lines captured by the clinicians may be inadequate, as most of them have an inherent lack of wettability that may prevent adequate registration of soft- and hard-tissue details. The inability of the impression materials to adequately displace soft tissues, fluids, or debris mandates adequate isolation. The gingival displacement procedure allows the impression material to flow apical to the subgingival finish line, thereby registering it and an area apical to it. These procedures lead to easy instrumentation, clear visualization, and good impression, resulting in a quality prosthesis having a marginal fidelity and a sound emergence profile.
Gingival displacement is defined as the deflection of the marginal gingiva away from the tooth (Glossary of prosthodontics; The Academy of Prosthodontics, 2005). According to studies done by Nemetz et al., Weir and Williams, Benson et al., and Cassidy and Gutteridge, gingival displacement is performed to create sufficient lateral and vertical space between the preparation finish line and the gingival tissue to allow the injection of adequate bulk of impression material into the expanded gingival crevice.,, According to the studies conducted by Laufer et al., Donovan, and Chee, the critical sulcular width has been reported to be approximately 0.15–0.2 mm at the level of the finish line. Impressions which record less sulcular width have higher incidences of voids and reduced marginal accuracy.,
Exposing the gingival margins of a preparation prior to making impression may be one of the most difficult procedures for the dentist to perform. This difficulty is further complicated by variations in the sulcular depth, distendability of gingival tissues, degree of gingival inflammation, level of margin placement, and tissue laceration.
Several clinical methods are available for adequate gingival displacement, including mechanical displacement, chemicomechanical displacement, electrosurgery, and rotary gingival curettage. The mechanical method of gingival displacement using retraction cord has been a standard for several years. It acts by physically pushing the gingiva away from finish line, but its effectiveness is limited because of its inability to control the sulcular fluid seepage.
The chemicomechanical methods using cords impregnated in hemostatic agents are the most commonly advocated. Enlargement of gingival sulcus as well as control of fluids seeping from the walls of gingival sulcus is readily accomplished by combining chemical action with pressure packing. The retraction cord mechanically displaces the gingival tissue and absorbs moisture contamination in the gingival sulcus, while the chemical agents control hemorrhage and shrink the gingival tissue, but the placement of the cords into the gingival crevice may cause slight trauma to the sulcular epithelium and is time-consuming as well.,
A complete paradigm shift has been made with the introduction of a very novel idea to achieve retraction and hemostasis at the same time. Due to shortcomings of conventional cord, cordless retraction materials have evolved and are becoming popular. A cordless retraction material is in the form of a paste-like material and is supplied with a specialized dispenser. It displaces gingiva by means of its high viscosity when injected into the sulcus. It has improved the ability to achieve tissue management with less trauma to gingival tissues even under the most difficult clinical situation and is less time-consuming.
Most studies on cordless techniques are demonstrations of their clinical use; their effects on the gingival and periodontal tissues are not well documented (Poss 2002, Shannon 2002, Smelltzer 2003). Various studies investigated the effects of different retraction techniques on the gingival and periodontal health but did not test the effectiveness of gingival displacement. This study was focused on evaluation and comparison of the amount of displacement of free gingiva with the use of a new less viscous syringeable retraction paste and more viscous cordless retraction system. Both are cordless chemicomechanical method of gingival displacement wherein the material is placed into the gingival sulcus with no pressure.
Expasyl, a paste-like material containing aluminum chloride as the hemostatic agent and kaolin as the expanding material, is dispensed by means of catridge and applicator gun. According to studies done by Prasanna et al., Expasyl showed a better ability in achieving horizontal displacement of the gingival sulcus than the knitted impregnated retraction cord. According to studies done by Al Hamed, Donovan, and Polat, Expasyl contains 15% aluminum chloride, which has been reported to result in local tissue damage and transient ischemia in concentrations >10%. All groups showed tissue recovery after 7 days. Expasyl group showed slower healing. Al Hamed also stated that Expasyl caused slightly more inflammation than Magic Foam Cord and Ultra Pak knitted cord and had a higher rate of postoperative dentin hypersensitivity. It also caused less histologic damage than a retraction cord technique and was easy to place.
According to studies conducted by Baharav et al., sensitivity was induced by Expasyl in some patients. This might be attributed to its acidity, which may have affected the patency of the dentinal tubules. Yang JC et al. observed less bleeding and pain with the cordless techniques compared with the use of traditional retraction cord. According to Al Hamed, the Expasyl group had the highest gingival index compared with others and showed slower healing. Its use might cause sensitivity in a small number of cases.
To overcome the shortcomings of Expasyl, this study was conducted to compare it with newly introduced less viscous Dryz retraction system. Dryz gingival retraction paste varies in its composition comprises of aluminum chloride hexahydrate as a hemostatic agent and is dispensed by the syringe and applicator tip. Dryz was easier in application and less viscous as compared to Expasyl.
In this study, thirty patients were selected out of which 15 patients had two abutments in anterior region of jaw and other 15 patients had two abutments in posterior region of jaw. All the measurements in the study were made by single operator to avoid interoperator variability.
Both syringeable retraction paste and viscous retraction system were applied on the same prepared abutments at an interval of 7 days. During this interval, provisional restoration was placed to protect abutments. Same abutment ensured similar gingival biotype. To standardize, only the visible and accessible buccal aspects of teeth were evaluated.
According to studies done by Feng et al. and Ruel et al., interval of 7 days is given to ensure complete healing of gingival sulcus., Al Hamed also stated that after 7 days, the gingival index returned to a nonsignificant level compared with baseline except for Expasyl, which was still significant. Ruel et al. and Wassell et al. reported that gingival retraction with cord caused destruction of the junctional epithelium that took 8 days to heal and caused gingival recession of about 0.2–0.1 mm. A double-mix single-step putty wash technique of impression making was followed. The manufacturer's recommendations on working and polymerization times were strictly followed. After tooth preparation, three impressions for each patient were made, one without retraction, second after application of syringeable retraction paste, and third after application of viscous retraction system at an interval of 7 days. This was followed by fabrication of definitive type IV gypsum cast. Undamaged retrieved casts were sawed out, buccolingually from buccal to lingual at buccal ridge with the help of die cutting saw followed by measurement of the width of the retracted gingival sulcus under a stereomicroscope using an image analysis software De Winter image analysis software (Dewinter Optical, Inc., New delhi, India). The width was measured as the distance from the abutment tooth to the crest of the free gingiva.
From the results and clinical point of view, the viscous retraction system was found to be more effective in gingival retraction, whereas syringeable retraction paste was easier in placement and caused less sensitivity.
| Conclusion|| |
Within the limitation of this study, it can be concluded that:
- Amount of mean horizontal gingival retraction attained by less viscous syringeable retraction system was higher than control but statistically not significant in anterior segment, whereas in the posterior segment, it was statistically significant
- Amount of horizontal retraction attained by more viscous cordless method was statistically significant in both anterior and posterior segment compared to control
- Application of syringeable retraction system was easier to place and more comfortable to patients compared to more viscous cordless method
- Selection of gingival retraction system can be based on the clinical situation and the individual clinician's preference.
Further studies will be necessary to confirm the results of the presentin vivo study.
In this study, more viscous cordless method was found to be more effective in gingival retraction, whereas less viscous syringeable retraction system was easier in placement and caused less sensitivity. Finally, the choice of which gingival retraction system to be used still depends on the clinical condition and operator preference.
Suggestions for future study
Further studies are required on these two gingival retraction system based on variables which were not considered in this study like distendability of gingiva and gingival biotypes.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]