Retraction Materials Research Articles

COMPARITIVE EVALUATION OF HORIZONTAL GINGIVAL DISPLACMENT USING STAY-PUT RETRACTION CORD AND ASTRINGENT RETRACTION PASTE: AN IN VIVO STUDY

Introduction: Gingival retraction cord is the most commonly used gingival displacement material however, it causes discomfort and produces damage to the periodontium. Various new gingival retraction materials have been introduced to overcome these problems. Aim: Thisstudy aims at comparative evaluation of horizontal gingival displacement using Stay-put retraction cord and Astringent retraction paste. Materials and Methods: A total of 40 subjects were selected and 40 samples were made for the study. Samples were divided into two groups,20 subjects in each group) depending on the materials used for gingival displacement.The impressions obtained after placing retraction system were poured in type IV die stone.The amount of gingival displacement was then measured as a distance from the tooth to the crest of the gingiva in a horizontal plane using stereomicroscope &analysed in image analysis software. Results: Among the experimental groups, astringent gingival retraction paste showed the highest value for gingival displacement (0.518mm) and the stay‑put retraction cord (0.435mm ) showed the least value. Conclusion: Within the limitations of this in vivo study, astringent gingival retraction paste showed the highest value for gingival displacement whereas, stay‑put retraction cord showed the least value.

Comparative evaluation of gingival displacement produced by three different gingival retraction materials

Aim: To compare and evaluate the gingival displacement produced by three different gingival retraction materials. Materials and Methods: A study was conducted to evaluate the gingival displacement produced by three gingival retraction materials. 12 subjects were selected for the study. T-stat retraction paste system (Nexobio co.Ltd,Korea), 3M ESPE Retraction Paste (3M Deutschland GmbH, Germany), Roeko Stay- put retraction cord (Coltene Whaledent Pvt. Ltd.) were used in the study. Results: Out of the three materials used, lateral displacement was maximum with the Stay-put retraction cord followed by 3M retraction paste and least by T-Stat retraction paste. All the materials produced acceptable amount of vertical gingival retraction. When compared Stay-put retraction cord was found to be most effective among the three materials. On comparison of the cordless retraction materials, it was found that the material which was more viscous in consistency (3M retraction paste) was able to produce more lateral gingival displacement than the material having less viscosity (T-stat retraction paste) even though both the cordless materials provided almost similar amount of vertical gingival displacement. The overall gingival retraction produced by the Stay-put cord was the highest followed by 3M retraction paste and least by the T-stat retraction paste.

A Comparison of Force Decay between Coil Spring, Elastomeric Chain and Tie-backs in Various Alcohol Concentrations found in Mouth Rinse: An In-vitro Study

Background: The ability to close space efficiently in Orthodontics is of major clinical importance. Elastomeric power chain, coil spring, and tiebacks are commonly used in Orthodontics to achieve tooth movement during the closure of spaces. Many mouth rinses which are used by the patients to achieve good oral hygiene affect the properties of the material used during treatment resulting in force decay if they contain alcohol.
 Aim: To know the effect of mouth rinses containing different alcohol Concentrations on the force decay of retraction materials.
 Materials and Methods: A study was carried out to test the effect of alcohol exposure found in mouth rinses on orthodontic NiTi closing coils, elastomeric chains, and tie-back. A total of 135 specimens were divided into one control group and two test groups submerged in artificial saliva at 37⁰ C. Two test groups each of them exposed to different alcohol-containing mouthwashes (Listerine and Povidone-iodine) for 60 seconds twice a day and the control group were exposed only to deionized (DI) water for 28 days. Force measurements were taken at six-time points (initial, 7 days, 14 days, 21 days, and 28 days) using a digital force gauge.
 Results: The comparison between the tensile strength was made by digital force gauge and the p-value (≤ 0.05) for tensile strength was derived by ANOVA test, multiple comparisons, and Tukey’s correction. Significant force decay was seen in test groups when compared to the control group.
 Conclusion: Force degradation of retraction products used during orthodontic treatment was effected by mouth rinses containing alcohol.

Influence of Photodynamic therapy and different gingival retraction agents on bond integrity of composite to dentin

The present study was undertaken to evaluate the influence of gingival retraction agents (Expasyl and Viscostat) and different conditioning methods (Total-etch, Self-etch, and PDT) on bond integrity of composite to dentin. One hundred and eighty, third molars were collected cleaned and disinfected in thymol solution. The specimens were rooted vertically up to cementoenamel junction within polyvinyl cylinders (PVC). Based on gingival retraction materials samples were divided into three groups (n = 60). Group A: dentin applied with Expasyl; Group B: Viscostat was applied on dentin and Group C: Control. Dentin surface was treated with different surface conditioners. Etch and rinse, PDT MBP, and Two-step self-etch. A bonding agent was applied and composite buildup was done. Samples were placed in the universal testing machine for SBS. Bond failure was assessed using a stereomicroscope. Analysis of variance (ANOVA) and Tukey's post hoc test compared the means and standard deviations (SD) after SBS testing (p = 0.05). The highest score of bond strength was exhibited by group C1 (21.14 ± 1.05 MPa-Etch & rinse + Tetric-N- Bond) whereas group C2 (12.15 ± 0.28 -PDT MBPS + Tetric-N-Bond, No treatment group) demonstrated the lowest SBS. Based on the application of haemostatic agent, bond values among subgroups A1 (18.75 ± 1.05 MPa - Expasyl + Etch & rinse + Tetric-N-bond) and B1 (17.84 ± 0.11 MPa -Viscostat + Etch & rinse + Tetric-N-Bond) was comparable (p>0.05). Based on the conditioning methods, bond scores among groups C1 (21.14 ± 1.05 MPa -Etch & rinse + Tetric-N- Bond) and C3 (19.05 ± 1.28 MPa -Clearfill SE) were comparable (p >0.05). Viscostat and Expasyl result in compromised bond integrity of composite restoration to dentin in etch and rinse and self-etch group compared to no treatment group. However, the pre-application of Viscostat and Expasyl on dentin conditioned with PDT improved bond integrity of composite resin.

RECENT ADVANCES ON GINGIVAL TISSUE MANAGEMENT IN RESTORATIVE DENTISTRY

Marginal integrity is one of the main factors that contribute to the outcome of a restoration and longevity of the restoration and cast restorations. An increased significance on the perio–restorative interface in restorative dentistry is essential to enable the utilization of the concept of biologic width in a practical manner. The goal, regarding the management of gingival tissues, is to ensure that the peridontium is in a healthy state. The oral cavity is a difficult to treat because of lips, cheeks, and tongue that hinders and makes it difficult to visualize and manipulate instruments in the area to be treated related. Gingival retraction is essential to perform better when the finish lines of the restoration is below the gingival margin. There are various gingival retractions that have been employed previously like mechanical, chemical, surgical and chemomechanical procedures. These methods not only provide an ideal working environment and ample vision, but also maintain hemostasis to certain extent. The choice of a retraction method depends on clinical situation and accessibility. The purpose of this review is to demonstrate the recent retraction materials and techniques.

The Influence of Hemostatic Agents and Cordless Gingival Retraction Materials on Smear Layer: An Ex vivo Scanning Electron Microscope Analysis.

Context:Cordless gingival retraction materials are now routinely used method for gingival retraction. Although evidence-based information is available on the effect of gingival displacement cord and cordless system on the effectiveness of displacement and the periodontal health, there is a lack of literature regarding the effect of cordless retraction agents on enamel and dentin substrates.Aim:The purpose of this investigation was to analyze the changes on the smear layer induced by the hemostatic agent and cordless retraction material at scanning electron microscopic level.Materials and Methods:Ferric sulfate (15.5% m/v), expasyl, and magic foam cord were evaluated. Buccal surfaces of 16 recently extracted mandibular premolars were prepared for metal-ceramic crowns, and four teeth each were exposed to ferric sulfate solution, expasyl, and magic foam cord, respectively, for 5 min. Teeth in the control group were exposed to distilled water. The assessment of changes was performed using a scanning electron microscope (SEM).Results:SEM exhibited smear layer covering the dentin and occluding the dentinal tubules in the control group. Exposure to ferric sulfate caused the opening of few of the dentinal tubules whereas expasyl caused the partial removal of smear layer with dentinal plugs partially occluding the openings of most of the dentinal tubules. The specimens treated with magic foam exhibited a smear layer similar to the control group.Conclusions:The smear layer was affected most with ferric sulfate solution, followed by expasyl and magic foam cord. Magic foam cord did not affect the smear layer.

A randomized controlled clinical trial comparing the use of displacement cords and aluminum chloride paste.

This clinical study measured the change in opening and height of the displaced gingiva using paste and cord retraction materials for definitive impression making of natural teeth and assessed if they were comparable and clinically acceptable. Impressions of 4 maxilla premolars from 10 participants were taken using a split-mouth protocol. All participants were free of periodontal disease, had a thick biotype, a minimal of 3 mm height of keratinized gingival tissue and gingival sulci depths of 2 mm. The bleeding index (BI), gingival index (GI) plaque index (PI), sulcular depth, level of attachment and tooth sensitivity were recorded at baseline, just after retraction, at 24 hours and at 2 weeks. Impressions were poured in stone and then after initial analysis were cross-sectioned to allow measurements of the gingival height change and gap size to be recorded. The paste produced a slightly smaller gap compared to the cord (0.041 mm less, P = .014) whilst the mean displacement for the cord was 0.282 mm and paste was 0.241 mm respectively. Gingival height with the paste was 0.047 mm lower than that achieved by the cord (P = .208). Cord and paste retraction produced comparable clinically acceptable gingival gaps, with the cord producing statistically larger gap size. The cord and paste retraction materials produced comparable clinically acceptable gingival retraction.

Effect of contemporary retraction agents and cleaning with hydrogen peroxide on the polymerization of elastomeric impression materials.

The aim of the study is to investigate the polymerization inhibition of elastomeric impression materials vinylpoly siloxane (VPS) and polyether (PE) when used in combination with retraction materials with and without subsequent cleaning with hydrogen peroxide (H2O2). Methods: Seven stainless steel specimens were fabricated. Four hundred and twenty impressions were made with three different elastomeric materials (140 each) as follows: group 1: VPS-Panasil; group 2: VPS-Express; group 3: PE-Monophase. Each material group was further subdivided into seven subgroups, based on use of no retraction material (control), three different retraction materials [Retraction capsule (RC3M), Dryz, Expasyl], and two cleaning techniques (water and H2O2). All subgroups included 20 impressions, which were made by a single operator using an automix gun. Evaluations were made using a visual scale by three calibrated examiners blindly and independently. Subjective categorization of the impressions were made as inhibited and uninhibited. Data were analyzed using Fisher's exact test and significance was set at p < 0.05. Results: Inhibited impressions were lower than uninhibited impressions among VPS materials (Panasil and Express); Panasil and Express showed comparable (p > 0.05) impression retardation. PE showed significantly higher inhibition compared to VPS materials (p < 0.05). Expasyl showed significantly higher polymerization inhibition than other retraction materials (p < 0.05). The use of H2O2 for cleaning showed significant reduction in polymerization inhibition than cleaning with water for Expasyl (p < 0.05). Conclusion: Overall contemporary retraction materials showed low potential for polymerization inhibition of elastomeric impression materials. Expasyl should be cleaned with H2O2 prior to impression making. However, Dryz and RC3M can show accurate impressions with water cleaning alone.

Comparative Evaluation of the Amount of Gingival Displacement Using Three Recent Gingival Retraction Systems - In vivo Study.

Background:Gingival retraction cord is the most commonly used gingival displacement material; however, it causes discomfort and produces damage to the periodontium. Various new gingival retraction materials have been introduced to overcome these problems. This in vivo study was conducted to compare the efficacy of three recent gingival displacement materials in achieving gingival tissue displacement.Materials and Methods:A total of 10 subjects was selected and 40 samples were made for the study. Samples were divided into four groups depending on the materials used for gingival displacement. The schedule for gingival displacement and impression making followed Latin block design. On day 1, baseline impression was made without gingival displacement. On day 2, day 22, and day 42 impressions were made after gingival displacement on intact maxillary right central incisor with any one of the three agents. The amount of gingival displacement was then measured as a distance from the tooth to the crest of the gingiva in a horizontal plane using stereomicroscope.Results:Statistical analysis was performed using one-way ANOVA test. The amount of gingival displacement obtained by all the experimental groups was more than the control group (P < 0.01). Among the experimental groups, astringent gingival retraction paste showed the highest value for gingival displacement (0.50 mm) followed by the stay-put retraction cord (0.48 mm), whereas expasyl (0.34 mm) showed the least value.Conclusion:Within the limitations of this in vivo study, astringent gingival retraction paste showed the highest value for gingival displacement followed by stay-put retraction cord whereas, expasyl showed the least value.

Comparison of Gingival Retraction Materials Using a New Gingival Sulcus Model.

To investigate the pressure generated by different retraction materials using a novel gingival sulcus model. A gingival sulcus model was made using a polymer frame filled with silicon. A pressure sensor and a sulcus-fluid simulation were embedded into the silicon chamber to evaluate the pressure generated by different retraction materials. Six sizes of Ultrapak retraction cords (Ultradent, sizes #000 - 3), 4 retraction pastes (Expazen, Expasyl, Acteon, Access Edge, Traxodent) and 2 retraction gels (Sulcus Blue, Racegel) were analyzed. The mean and median pressure, interquartile range, and standard deviation (SD) of n = 10 repeated measurements were calculated. Statistical analysis was conducted by Kruskal-Wallis test for differences between the main groups of retraction materials, and Mann-Whitney U-test was performed to analyze differences between the single retraction materials. Pressure (mean ± SD) generated by retraction cords increased with increasing size (48.26 ± 11.29 kPa, size #000 to 149.27 ± 28.75 kPa for #3). There was a significant difference between sizes (p < 0.01), except in #0 versus #1, and #2 versus #3. Retraction pastes generated pressures that ranged from 82.74 ± 29.29 kPa (Traxodent) to 524.35 ± 113.88 kPa (Expasyl). Retraction gels generated pressures from 38.96 ± 14.68 kPa (Racegel) to 95.15 ± 24.18 kPa (Sulcus Blue). Pressure generated by Expasyl was significantly higher than pressure generated by all other tested materials (p < 0.001). Pressure generated by retraction pastes and gels depends on the consistency of the retraction material, while pressure generated by retraction cords increased with increasing size of cords. Expasyl was found to generate the highest pressure compared to all other retraction materials.

The Effect of Gingival Retraction Cord on Periodontal Health Compared to Other Gingival Retraction Procedures: A Systematic Review

Background: An accurate impression is obtained for the fabrication of fixed restorations only when the gingival tissue is managed properly. And this is especially true when the location of the finish line is at, or within, the gingival sulcus. Gingival retraction is an important aspect of currant impression techniques in fixed prosthetic procedures. Effective gingival retraction prior to taking an impression without damaging periodontal tissues is very important in long-term success of cast restorations. Purpose: To collect and evaluate, in a systematic manner, data available on the post-operative effect of retraction cords on gingival tissue in patients with healthy gingiva compared to cordless techniques in respect to effect on gingival recession, parameters of gingival inflammation and patient comfort. Methods: PubMed/Medline, Science Direct, ISI Web of Science, the Cochrane library, EMBASE, and Google Scholar databases were searched. The studies were chosen according to the inclusion criteria followed by data extraction, and quality check. Results: 85 potentially eligible articles were identified, of which only 5 fulfilled the objective of the study and were included. Five studies reported that the gingival retraction techniques affected the gingival health with a variable degree level and this effect was temporary in nature taking in consideration the health of the gingival tissues. One study compared three different techniques of retraction materials and reported that temporary gingival inflammation was observed with all techniques and Expasyl had the greatest effect with slower recovery. Bleeding was induced by the cordless techniques neither during nor after retraction. One study investigated non-aluminum chloride-containing injection-type retraction material (Korlex-GR) compare it with 2 other commercial retraction materials (Ultrapak 1, a medicated retraction cord, and Expasyl), there results indicated that the non-aluminum chloride-containing injection-type retraction material is as effective as the other 2 materials for gingival retraction but produces less pain and limits injury to the gingival tissue during the procedure. Conclusions: It may be suggested that all tested gingival retraction technique will affect the gingiva negatively temporarily, however, well-fitted fixed dental prosthesis and its procedures performed to periodontaly healthy subjects will have a reversible effect on the periodontal tissue health.

The rabbit gingival tissue response to retraction liquids and tetrahydrozoline

BACKROUND/AIM: Retraction agents for temporary vertical and lateral suppression of gingival tissue as well as bleeding control and fluid flow in the gingival sulcus are expected to have maximal efficiency without irreversible damage of local tissue and adverse systemic effects. The research started from the assumption that tetrahydrozoline is a biologically more acceptable means of gingival retraction than commercially available preparations. The aim of the study was to comparatively analyse the inflammatory effects of different retraction materials and tetrahydrozoline. The effect of retraction liquid on the basis of aluminum chloride and epinephrine and tetrahydrozoline hydrochloride on gingival tissue of rabbits was investigated. The application time in the rabbit's gingival sulcus was 7 minutes. Tissue biopsy was performed after an hour, a day, and 7 and 30 days. Tissue preparations were analyzed under a microscope. The obtained results indicate a reversible damage of gingival tissues as a result of local application of aluminum chloride- and epinephrine-based retraction agents. Their use led to acute inflammatory response after an observation period of 1 and 7 days. After 30 days reparation of damaged tissue was observed. The use of tetrahydrozoline resulted in a visibly weaker inflammatory response. Retraction liquids insertion led to an acute inflammatory response of gingival tissue which in time assumed a chronic character. The inflammatory response to the administered tetrahydrozoline was significantly lower with complete reparation of gingival tissue. Taking this fact into account it is recommended as a potential retraction agent.

Effect of retraction materials on gingival health: A histopathological study

Background:Gingival retraction methods are used in dentistry for impressions of subgingival crown margins, such as, mechanical, chemical, chemicomechanical, and surgical. These methods may injure the gingival sulcular epithelium. Hence, the present study is carried out to evaluate the effect of different retraction materials, such as, Expasyl, Magic Foam Cord, and impregnated retraction cord on the gingival sulcular epithelium.Materials and Methods:This study included 30 cases of bilateral premolar extraction patients with Loe and Silness gingival index zero. Retraction materials were kept in the dry, isolated labial gingival sulcus for the required time. The retraction materials were removed by rinsing with water. Retracted gingiva of 2 – 3 mm from the gingival margin along with the tooth was extracted and the decalcified sections were microscopically studied. Data analysis: Data were analyzed by applying the chi-square test.Results:This study showed better results with retraction paste as compared to the retraction cord, and there was a significant association between retraction materials and the relative degree of injury to the sulcular epithelium.Conclusion:There is a significant association between retraction materials and gingival sulcular epithelium. It can be stated that impregnated retraction cord, may be used commonly but it needs proper tissue manipulation and is technique sensitive. Newly advanced material in the form of retraction paste like Expasyl or Magic Foam Cord was found to be better than cord as assessed histologically, it respects periodontium.

Tissue management with a new gingival retraction material: A preliminary clinical report

A new retraction material (Merocel) was evaluated in a clinical trial with 10 selected abutments. Each selected abutment required an anterior single unit. A comparison of probing attachment level, bleeding on probing, and plaque index demonstrated highly successful periodontal maintenance. The main advantage of merocel retraction material is that it is capable of innocuously expanding the gingival sulcus. This preliminary study suggested that a Merocel strip was a predictable retraction material in conjunction with impression procedures. The material was also evaluated by scanning electron microscopy and demonstrated promise in this investigation. The Merocel strip shows potential for other applications, but limitations of this material indicated that evolution of atraumatic gingival retraction should continue.