Sage Journals: Discover world-class research

Abstract

Objective

To describe the existing knowledge on the efficacy of the different gingival retraction systems (GRSs) in gingival displacement, to know their effects on biological functions of human gingival fibroblasts (HGFs), and on the expression of inflammatory mediators (TNF-α and MCP-1) in gingival crevicular fluid (GCF), and saliva.

Methods

The protocol used for this systematic review was registered in INPLASY: 202410005. A digital search was performed in the databases PubMed/MEDLINE, Scopus, Science Direct, Web of Science, and Google Scholar of the literature published in the English language in the last 17 years (from December 10th, 2006, to May 15th, 2023), and included retrospective randomized clinical studies, prospective, and in vitro experimental studies. In addition, PRISMA criteria were followed. The methodological validity of the selected articles was assessed using Joanna Briggs Institute (JBI) critical appraisal tool, and the modified Consolidated Standards of Reporting Trials checklist (CONSORT).

Results

27 articles published between 2006 and 2023 were evaluated. Six hundred 32 subjects, aged between 18 and 65, participated in the clinical studies. 93.7% of the studies assessed periodontally healthy patients, and only 6.3% evaluated patients with mild gingivitis. Also, 882 teeth were samples, of which the majority were posterior teeth (54%). The most commonly used GRSs was aluminum chloride gingival retraction paste (74%). The GCF samples were taken in 67% of the studies, and ELISA was used in all studies (100%) to determine inflammatory mediators. The most frequently analyzed marker was TNF-α (67%).

Conclusion

The system Merocel Strips (Mystic, conn, USA) achieved the highest level of gingival displacement (1.66 ± 3.7 mm). In addition, the braided cords produced the lowest TNF-α levels (0.43 ± 0.08pg/mL). Astringent systems such as ferric sulfate had higher toxicity in HGFs.

Keywords

Gingival retraction methods gingival fibroblasts cytokines astringents cordless methods vasoconstrictors

Introduction

The main purpose of prosthetic restorations in addition to meeting the requirements of function, esthetics, and biocompatibility with the supporting tissues of the teeth is to preserve the remaining tooth structure^1,2 and not just to make the decision to extract the tooth involved for the sake of replacing what is missing.³ Periodontal health before, during and after prosthetic treatment is an important aspect of successful rehabilitation in the patient with this type of problem.⁴ The formation of dentobacterial plaque in an inadequately placed prosthesis is an important etiological factor in the inflammation and consequent destruction of periodontal tissues. It has been shown that deep subgingival (below gingival) prosthetic margins that alter the biological thickness are associated with an increase in clinical parameters such as gingival index (GI), plaque index (PI), bleeding on probing (BP), probing depth (PD) and clinical attachment loss (CAL), which often tends to increase periodontal problems and complications such as gingival recession.^5,6 However, with good training regarding maintenance of thorough oral hygiene by the patient, and good management of restorative and soft tissue procedures, periodontal health can be preserved.^7–10 Notably, the prosthetic margin should be 0.5 mm from the healthy marginal ridge or 3-4 mm from the alveolar bone gingiva and follow the natural scalloping of the gingiva and alveolar process.^11,12

Prosthetic restorations that are well contoured and have tight margins on the finishing line of the tooth preparation, especially when they are juxtagingival (same gingival level) or subgingival, are achieved thanks to an adequate impression taking^13,14 preceded by the use of an excellent gingival retraction system (GRSs).^15,16 The objective of using GRSs is: (1)The displacement of the marginal gingiva, that is, they allow the folding of the gingival margin at a considerable distance from the tooth surface, providing a virtual vertical and horizontal space between the tooth surface and the junctional epithelium where the impression material is to be applied. (2) At least 0.2 mm width in the sulcus is needed to decrease the risk of tearing of the impression material and a reduction in marginal accuracy. 3)In addition, it is important that a small amount of impression material flows past the preparation, this in turn will allow precise trimming of the recovered die.¹⁷ In the face of failure to use GRSs, this would lead to compromised marginal integrity (failure to adequately reproduce the finishing line of the previously prepared teeth), recurrent caries, inflammation and destruction of the supporting tissues of the teeth.¹⁸

Currently, there are two methods of gingival retraction, which include surgical procedures using electrosurgery, rotary curettage and lasers,¹⁹ and non-surgical procedures, which include mechanical and chemo-mechanical methods that can be used individually or in combination.²⁰ In relation to chemo-mechanical methods, that is the use of retraction cords and medications, the chemical substances used are classified into vasoconstrictors such as α- and β-adrenergics,²¹ astringents such as ferric sulfate, chloride, aluminum sulfate and potassium,²² as well as wireless retraction methods, which include the use of biomaterials such as magic foam cord, retraction paste, retraction capsule, among others.²³ Depending on the case and the clinical scenario, a wide variety of gingival retraction techniques are required; however, scientific evidence suggests that the most commonly used displacement method is the chemomechanical technique.^24,25 Presumably, the dentist and prosthodontist are familiar with the workflow of the clinical steps for determining the degree of lateral gingival displacement. In addition, several studies have compared the clinical efficacy of different GRSs as a function of the biomaterials and techniques used.^26–41

Ideally, GRSs should be easy to apply and manipulate, should be mostly inexpensive and easily accessible, as well as should have antimicrobial activities and show less negative effects on the periodontium, that is, more biocompatible with the cells that constitute periodontal tissues.²⁵ In this regard, several in vitro studies have evaluated the biological effects of human gingival fibroblasts (HGFs) exposed to different GRSs, including activities such as cell viability and proliferation, cytoskeleton organization and reactive oxygen species (ROS) determination. This by applying chemicals such as α- and β-adrenergic vasoconstrictors, astringents and wireless.⁴⁰ Researchers are trying to find new drugs with less cytotoxic effects on these cells,^42–49 and for the most part, it has been shown that, experimental gels based on 0.05% HCI-tetrahydrozoline in different dilutions (1:10 and 1:20) are biocompatible with periodontal tissues and can be considered as new chemical gingival retraction vasocontrictor agents.^42–44,46

Therefore, this systematic review aimed:

• To describe the clinical aspects of different GRSs on the effectiveness of gingival displacement.

• To evaluate the effects of different GRSs on the biological functions of human gingival fibroblasts.

• To evaluate the influence of different GRSs on the levels of inflammatory mediators TNF-α, and MCP-1 in GCF and saliva.

Materials and methods

The present study followed the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analysis).⁵⁰ The protocol used for this systematic review was registered in the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY) (202410005).

Review question

The protocol aimed to answer the following three questions: “Which GRSs have the greatest effectiveness on the degree of gingival displacement?” “Do GRSs affect the biological responses of gingival fibroblasts in vitro studies?” “What are the effects of GRSs on the levels of inflammatory mediators?” The questions followed the guidelines according to the PICOS strategy:

• Population: Gingival tissues around teeth to receive fixed dental prostheses from adult subjects and gingival fibroblasts.

• Intervention: GRSs; retraction cords, pastes, strips, lasers, and other chemicals.

• Comparison: The previously mentioned methods served for comparisons. Also, teeth without pre-displacement.

• Outcomes: Degree of clinical gingival displacement, the response of gingival fibroblasts to pre-displacement GRSs exposure, and levels of inflammatory mediators.

Eligibility criteria

The research focused on which type of GRSs are ideal for gingival sulcus impressions and those that measure the degree of gingival displacement; in vitro research studying the effects of different GRSs on the biological functions of fibroblasts such as cell morphology, viability, and cytotoxicity; and research on the influence of GRSs on the levels of different inflammatory mediators were included. Articles had to be published in English and have full text available. Original research, such as retrospective and prospective randomized clinical trials and in vitro experimental studies, were included in the present investigation. Studies that evaluated the response of cells other than gingival fibroblasts were eliminated. Case reports, editorials, short communications, and research conducted in a language other than English were excluded.

Electronic search

A digital search was performed in the databases PubMed/MEDLINE, Scopus, Science Direct, Web of Science, and Google Scholar for literature published in the English language in the last 17 years (from December 10th, 2006, to May 15th, 2023). The search was limited to humans and cells (gingival fibroblasts).

Manual search

The reference lists of the selected articles were checked for cross-references. In addition, additional hand searches were performed in the following journals from 2006 to 2023: Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry, Journal of Prosthodontic Research, Journal of Advanced Prosthodontics, International Journal of Prosthodontics, European Journal of Prosthodontics and Restorative Dentistry, Journal of Esthetic and Restorative Dentistry, Journal of Prosthetic Dentistry, Journal of Indian Prosthodontics Society and Journal of Prosthodontics.

Search strategy

The search strategy included reviewing titles and abstracts to select articles that met the inclusion criteria and excluding those that did not. Keywords related to “gingival retraction agents/methods” were combined with keywords such as “gingival displacement,” “gingival fibroblasts,” or “inflammatory biomarkers.” Boolean operators “OR” and “AND” were used to combine the searches. The following MeSH terms and their combinations were used: (Gingival Retraction Systems, agents, methods) OR (Gingival Fibroblast) OR (Degree of displacement) OR (Vertical) OR (Horizontal) OR (Inflammatory Biomarkers) OR (Gingival Crevicular Fluid) OR (Salivary) OR (Vasoconstrictive Agents) OR (Oral Rehabilitation) OR (Hemostatics) OR (Astringents) OR (Cordless Retraction Methods) OR (Periodontal Health) OR (Gingivitis). Table 1 provides the complete electronic search strategy used in PubMed.

Table 1.

The full search strategy used in the PubMed database.

Database	Search strategy
PubMed	((((((((((((“Gingival retraction Techniques” [Mesh]) OR (“Fibroblasts/immunology” [Mesh] OR “Fibroblasts/microbiology” [Mesh])) OR “Biomarkers” [Mesh]) OR “gingival crevicular Fluid” [Mesh]) OR “Saliva” [Mesh]) OR (“vasoconstrictor agents/antagonists and inhibitors” [Mesh] OR “vasoconstrictor Agents/toxicity” [Mesh])) OR “Mouth Rehabilitation” [Mesh]) OR “dental Prosthesis” [Mesh]) OR (“Hemostatics/classification” [Mesh] OR “Hemostatics/immunology” [Mesh] OR “Hemostatics/toxicity” [Mesh])) OR (“Astringents/classification” [Mesh] OR “Astringents/immunology” [Mesh] OR “Astringents/toxicity” [Mesh])) OR “Periodontitis/immunology” [Mesh]) OR “Gingivitis” [Mesh]) AND “periodontal Prosthesis” [Mesh]

Database

Search strategy

PubMed

((((((((((((“Gingival retraction Techniques” [Mesh]) OR (“Fibroblasts/immunology” [Mesh] OR “Fibroblasts/microbiology” [Mesh])) OR “Biomarkers” [Mesh]) OR “gingival crevicular Fluid” [Mesh]) OR “Saliva” [Mesh]) OR (“vasoconstrictor agents/antagonists and inhibitors” [Mesh] OR “vasoconstrictor Agents/toxicity” [Mesh])) OR “Mouth Rehabilitation” [Mesh]) OR “dental Prosthesis” [Mesh]) OR (“Hemostatics/classification” [Mesh] OR “Hemostatics/immunology” [Mesh] OR “Hemostatics/toxicity” [Mesh])) OR (“Astringents/classification” [Mesh] OR “Astringents/immunology” [Mesh] OR “Astringents/toxicity” [Mesh])) OR “Periodontitis/immunology” [Mesh]) OR “Gingivitis” [Mesh]) AND “periodontal Prosthesis” [Mesh]

Methods of detection and data extraction

Two independent researchers (M.A.A.S and A.H) primarily screened the articles by reading the title and abstract. Subsequently, the content of each paper was summarized. The validity of the studies was assessed, and duplications were identified. The same investigators selected the articles that met the eligibility criteria or those with insufficient data. If any disagreement arose between the principal investigator, it was resolved by discussion with an independent third investigator. The following information was extracted for each article included:

• First author, year, and country.

• Type of study.

• Journal.

• Study population.

• Age.

• Gender.

• Gingival retraction system used.

• Location and number of teeth.

• Periodontal status.

• Cell type.

• Technique used.

• Oral fluid.

• Method of detection.

• Biomarkers.

Outcome measures

To evaluate the effects or influence of the different GRSs, the primary outcome was to determine the degree of gingival displacement and its possible impact on the condition of the periodontium. As a secondary outcome, articles evidencing the biological effects of gingival fibroblasts in response to GRS exposure were selected. As a tertiary outcome, articles that quantified the levels of different inflammatory mediators in response to the presence of GRSs on gingival margins were chosen.

Inclusion of evidence sources

Table 2 summarizes the membership of the studies selected for the objectives of this systematic review.

Table 2.

Contribution of the selected studies to the outcome.

	Primary Outcome	Secondary Outcome	Tertiary Outcome
Author/Year	To describe the clinical aspects of the different GRSs on the effectiveness of gingival displacement and periodontal health	To evaluate the effects of GRSs on the biological functions of gingival fibroblasts	To evaluate the influence of GRSs on the levels of inflammatory mediators
Nasim et al., 2023²⁶	✔
Kuhn et al., 2022²⁷	✔
Madaan et al., 2022²⁸	✔
Fernandes de Carvalho et al., 2021²⁹	✔
Kumari et al., 2021³⁰	✔
Değirmenci et al., 2021³¹	✔
Kuhn et al., 2021³²	✔
Rathod et al., 2021³³	✔
Qureshi et al., 2020³⁴	✔
Kavita et al., 2020³⁵	✔
Bennani et al., 2020³⁶	✔
Rayyan et al., 2019³⁷	✔
Mehta et al., 2019³⁸	✔
Gajbhiye et al., 2019³⁹	✔
Thimmappa et al., 2018⁴⁰	✔
Goutham et al., 2018⁴¹	✔
Nowakowska et al., 2021⁴²		✔
Nowakowska et al., 2020⁴³		✔
Nowakowska et al., 2014⁴⁴		✔
Cooper et al., 2013⁴⁵		✔
Nowakowska et al., 2011⁴⁶		✔
Nowakowska et al., 2010⁴⁷		✔
Liu et al., 2004⁴⁸		✔
Kopac et al., 2002⁴⁹		✔
Mathew et al., 2022⁵²			✔
Igic et al., 2019⁵³			✔
Feng et al., 2006⁵⁴			✔

Quality assessment of the selected studies

The methodological validity of the selected articles was assessed independently by two investigators (M.A.A.S and A.H). For randomized clinical trials and longitudinal studies, the critical appraisal tool of the Joanna Briggs Institute (https://jbi.global/critical-appraisal-tools) was used. This tool is based on a series of questions grouped according to the type of studies included in the systematic review that can be rated as “Yes”, “No”, “Unclear” or “Not applicable”. The selected articles were ordered by their design and a specific instrument was used for each group. Whereas, for studies with an experimental design (in vitro studies), the modified Consolidated Standards of Reporting Trials (CONSORT) ⁵¹ checklist was used.

For practical purposes and according to the assessment instrument, the risk of bias was classified as high when the study reached up to 49% of the “Yes” scores, moderate from 50% to 69% and low when it reached scores above 70%.

Result

Study selection and characteristics

Initially, 2,081 articles were identified. After eliminating duplicate studies and studies with abstracts unrelated to the review’s three objectives, 81 potentially eligible articles were selected. Applying the eligibility criteria, 61 articles were selected, and 20 were excluded. After removing duplicates, a full-text analysis of the studies was performed, and 27 articles were finally obtained for qualitative research (Figure 1). Tables 3, 4, and 5 summarize the salient details of the studies.^{26–49,52–54}

Figure 1.

PRISMA flow diagram. PRISMA: Preferred Reporting Items for Systematic and Meta-Analyses.

Table 3.

Summary of articles evaluating different GRSs on the level of lateral displacement and periodontal health.

Author (s)/Year/Country	Study type/Journal	Subjects/Age/Gender/GRSs	No. of teeth/Tooth location	Periodontal status	Findings and conclusions
Nasim et al., 2023/Pakistan²⁶	Randomized clinical study, Retrospective/European review for Medical and Pharmacological Sciences	n = 60Age: 33.5 ± 11.7Male: 22Female: 38Retraction cord (Retreat® K Henry Schei, Melville, NY, USA)PTFE cord (Minshoo®, Linan Linfeng Fluorine, Plastics, co. Ltd., Hangzhou, Zhejiang, China) polytetrafluoroethylene	n = 60Mandibular molars	Periodontally healthy	Compared to the retraction cord, a greater gingival displacement was achieved with the PTFE cord. In addition, there was a higher prevalence of bleeding and greater difficulty in applying the PTFE system compared to the conventional cordPTFE cord: 197.1 ± 34.2 µmRetraction cord: 167.7 ± 31.7 µm
Kuhn et al., 2022/Germany²⁷	Randomized clinical study, Prospective/Journal of clinical Medicine	n = 40Group A: Double cord technique (Retracto, Roeko, Langenau, Germany)Age: 24.0 ± 2.5Sex (m:f): 10:8Group B: Astringent retraction paste (3M oral Care, Seefeld, Germany)- aluminum chlorideAge: 24.2 ± 2.9Sex (m:f): 10:12	n = 80Both premolars	Mild gingivitis	Higher displacement was obtained in both horizontal and vertical directions using the double cord technique: p < .05Absolute sulcus depth after gingival displacementGroup A: 0.79 ± 0.19 mmGroup B: 0.70 ± 0.17 mmVertical gingival displacementGroup A: −0.39±0.19 mmGroup B: −0.31±0.15 mm
Madaan et al., 2022/India²⁸	Controlled clinical study, Prospective/Cureus	n = 20Both Sexes18 and 30 yearsN/EPre-displacement3M capsule (3M ESPE)Retraction cord (SURE-cord ® plus; Sure dent Corporation, Jungwon-gu, South Korea)Gingival retraction paste (Traxodent)Polyvinyl acetateStrips (Merocel; Merocel co., Mystic, CT)	n = 100Anterior teethN/E	Periodontally healthy	Polyvinyl acetate strips (Merocel) provided the maximum lateral gingival retraction among the four materials studied: p < .05Merocel strips: 706.35 ± 50.76 µmRetraction cord: 670.08 ± 46.30 µm3M capsule: 498.28 ± 43.37 µmTraxodent paste: 395.34 ± 23.40 µmPre-displacement: 164.70 ± 12.01 µm
Fernandes de Carvalho et al., 2021/Brazil²⁹	Randomized clinical study, Retrospective/European Journal of Prosthodontics and restorative Dentistry	n = 24Both SexesN/EGroup 1: Cords Impregnated with aluminum chloride (Hemostop ®)Group 1: Cords Impregnated with naphazoline hydrochloride (Legrand Collirium®)Group 3: Cords without any chemical substance	n = 72Upper Right and Left canine and Upper Left central incisor	Periodontally healthy	The aluminum chloride-impregnated cord showed higher gingival displacement, followed by the cord without chemical substance and the cord impregnated with naphazoline hydrochlorideGroup 1: 0.235 ± 0.0929 mmGroup 3: 0.212 ± 0.0809 mmGroup 2: 0.198 ± 0.0611 mm
Kumari et al., 2021/India³⁰	Randomized clinical study, Prospective/The Journal of Contemporary dental practice	n = 2018 yearsN/EGroup WR: Impression without retractionGroup A: Impression after retraction with gingival retraction cordGroup B: Impression after retraction with expanding polyvinyl siloxaneGroup C: Impression after retraction with aluminum chloride-containing paste	N/E	Periodontally healthy	The mean gingival retraction was highest for group C (0.43±0.09 mm), followed by group A (0.36±0.11 mm), B (0.33±0.08 mm) and WR (0.25±0.07 mm) p < .05
Değirmenci et al., 2021/Turkey³¹	Randomized clinical study, Prospective/Lasers in Medical Science	n = 5232.12 years20 males32 femalesRetraction cord group (Ultrapak retraction cord, Ultradent products Inc.)Cordless past System group (Traxodent; Premier dental products co)Er, Cr: YSGG laser Troughing	n = 60Mandibular 1° molars	Periodontally healthy	Er, Cr: YSGG laser Troughing procedure was found to be more advantageous as compared to the other two techniques, owing to the lower probing depth, gingival index, and bleeding on probing scores in the 1-year time frame
Kuhn et al., 2021/Germany³²	Randomized clinical study, Prospective/Journal of clinical Medicine	n = 40Gender distribution in both groups: 50% female, 50% maleGroup A: Double cord techniqueAge: 25.85 ± 6.82Group B: Kaolin paste containing Aluminium chlorideAge: 27.40 ± 9.91	n = 40Both premolars	Gingivally healthyArtificial gingivitis	For healthy gingiva, the cord technique achieved a better gingival displacement in the vertical direction than the paste techniqueMild gingivitis worsened the sulcus representation when using the cord technique but did not influence the sulcus representation of the paste technique. This means that the advantage of the cord technique concerning a better sulcus representation was lost to a great extent under the condition of mild gingivitis
Rathod et al., 2021/India³³	Randomized clinical study, Retrospective/The Journal of Contemporary dental practice	n = 60Both Sexes18 and moreN/EGroup 1: Expasyl (Kerr Corp., Orange, California, USA)Group 2: Magic foam cord (Coltene Waldent AG, Altstatten, Switzerland)Group III: Traxodent (Premier dental, Pennsylvania, USA)	n = 60N/E	Periodontally healthy	A more significant gingival displacement was observed in Group 3, followed by groups 1 and 2, with p < .05Group III: 0.644 ± 0.22 mmGroup I: 0.590 ± 0.11 mmGroup II: 0.528 ± 0.01 mm
Qureshi et al., 2020/India³⁴	Randomized clinical study, Prospective/Contemporary clinical Dentistry	n = 10Both Sexes18 and 25 yearsN/EGroup 1: Without any gingival displacementGroup 2: Stay-put gingival retraction cord (Roeko, Coltene/Whaledent, US)Group 3: Expasyl paste (Kerr, US)Group 4: Astringent paste (3M ESPE, Germany)	n = 40Maxillary Right central incisor	Periodontally healthy	The astringent paste produced the most significant amount of gingival displacement, followed by the stationary cord and Expasyl paste, p < .05Group 4: 500.530 ± 130.087 µmGroup 2: 483.810 ± 42-833 µmGroup 3: 346.540 ± 86.251 µmGroup 1: 156.540 ± 32.340 µm
Kavita et al., 2020/India³⁵	Randomized clinical study, Retrospective/Journal of Pharmacy & BioAllied Sciences	n = 60Both Sexes18 and 48 yearsN/EGroup I: Aluminium chloride retraction cordsGroup II: ExpasylGroup III: Tetrahydrozoline Soaked retraction cordGroup IV: No retraction cord	n = 60N/E	Periodontally healthy	The maximum gingival retraction was achieved with aluminum chloride retraction cords followed by tetrahydrozoline and Expasyl, p < .05Group I: 825.6 ± 34.2 µmGroup III: 742.3 ± 20.5 µmGroup II: 482.1 ± 26.9 µmGroup IV: 214.8 ± 13.5 µm
Bennani et al., 2020/New Zeland³⁶	Randomized clinical study, Retrospective/Journal of esthetic and restorative Dentistry	n = 10Both Sexes18 and 25 yearsN/ECord (KnitTrax, Pascal co., Inc. Bellevue, Washington) with aluminum chlorideRetraction paste (Expasyl, Pierre-Roland, Bordeux, France)	n = 40Premolars	Periodontally healthy	The cord impregnated with aluminum chloride produced a more significant gingival displacement compared to the retraction paste (Expasyl)Cord: 0.14 mmExpasyl: 0.04 mm
Rayyan et al., 2019/Egypt³⁷	Randomized clinical study, Prospective/The Journal of prosthetic Dentistry	n = 3018 males12 females25 and 35 yearsN/EGroup Tr (Traxodent; Premier dental products co)Group Es (Expasyl; Acteon UK)Group Ez (Expazen; Acteon UK)Group Mr (3M retraction; 3M ESPE)	n = 120Premolars	Periodontally healthy	Expasyl, Expazen, and 3M retraction displacement exceeded the 200 µm requirements for horizontal displacement, p < .05Group Tr resulted in the least vertical and horizontal displacementThe gingival index increased for all groups after 2 days
Mehta et al., 2019/India³⁸	Randomized clinical study, Retrospective/Contemporary clinical Dentistry	n = 45Both Sexes25 and 35 yearsN/EGroup I: Retraction cord Impregnated with 20% ferric sulfate (Stay-Put; Roeko)Group II: Magic foam (Coltene/Whaledent Inc)Group III: GingiTrac retraction System (GingiTrac; Centrix)	n = 45Maxillary/Mandibular 1° molar	Periodontally healthy	The maximum gingival retraction was produced by aluminum chloride-impregnated cord followed by magic foam and GingiTrac paste, p < .05Group I: 0.465627 mm ± 0.063066 mmGroup II: 0.294147 mm ± 0.056697 mmGroup III: 0.210993 mm ± 0.067358 mm
Gajbhiye et al., 2019/India³⁹	Randomized clinical study, Retrospective/Journal of Indian Prosthodontic Society	n = 10Both Sexes25 and 30 yearsN/EGroup 1: Retraction cord Impregnated with aluminum chlorideGroup 2: NoCord impression (polyvinyl siloxane)Group 3: Aquasil (polyvinyl siloxane)	n = 30Right Maxillary central incisor	Periodontally healthy	Retraction cord impregnated with aluminum chloride produces the maximum displacement followed by NoCord and Aquasil, p < .05Group 1: 0.27 mm ± 0.02 mmGroup 2: 0.26 mm ± 0.02 mmGroup 3: 0.22 mm ± 0,02 mm
Thimmappa et al., 2018/India⁴⁰	Randomized clinical study, Prospective/Journal of Indian Prosthodontic Society	n = 30N/ERetraction cord (Ultrapak, Ultradent products, USA) impregnated with 10% aluminum chloride (Roeko, Coltene Whaledent)Merocel strip (Mystic, conn USA)Magic foam cord (Coltene, Whaledent, Switzerland)	n = 30Mandibular first Molar	Periodontally healthy	Merocel strip provided the maximum amount of lateral and vertical gingival retraction than ultrapak cord and magic foam cord, p < .05Merocel strip: 1.66 mm ± 0.37 mmRetraction cord: 1.24 mm ± 0.19 mmMagic foam cord: 0.60 mm ± 1.9 mm
Goutham et al., 2018/India⁴¹	Randomized clinical study, Retrospective/The Journal of Contemporary dental practice	n = 45Both SexesThe average age was 28 yearsN/EGroup I: Retraction cord Impregnated with aluminum chloride SystemGroup II: Magic foam cord retraction SystemGroup III: Laser retraction system	n = 45Right or Left Maxillary central incisor	Periodontally healthy	More significant gingival displacement was observed with the use of a laser retraction system followed by aluminum chloride-impregnated retraction cord and magic foam cord retraction, p < .05Group III: 0.4800 ± 0.101 mmGroup I: 0.4400 ± 0.112 mmGroup II: 0.3133 ± 0.092 mm

Table 4.

Summary of articles evaluating different GRSs on the biological effects of HGFs

Author (s)/Year/Country	Study type/Journal	Cell type	Techniques	Gingival retraction systems	Findings and conclusions
Nowakowska et al., 2021/Poland⁴²	Experimental Study/Materials	HGFs	Cell Viability→ MTT AsayCell Proliferation→ BrdU assayCytoskeletal Organization→ Zyxin and F-actin Localization by confocal laser scanning microscopyOxidative Stress→ nitrite (NO2-) Concentration assayExpression of SOD1,SOD2,SOD3,HMOX1 and GPX1→ RT-PCR	Racegel Septodont (Cedex, France)ViscoStat clear (Ultradent products, Inc. South Jordan, UT, USA)Alustat gel (Cerkamed Nisko, Poland)Expasyl (KerrHawe SA Bioggio, Switzerland)Access FLO (Centrix Shelton, CT, USA)Astringent retraction past (3M ESPE St. Paul, MN, USA)Alustat foam (Cerkamed Nisko, Poland)Gel cord (Pascal International Bellevue Washington, USA)ViscoStat (Ultradent products, Inc. South Jordan, UT, USA)	The biological response of HGFs by injectable forms of astringents confirmed that these materials are safe for human periodontal tissues. Follow-up of this study by evaluating clinical effects is recommended to select the safest and most effective agents for the gingival displacement processIt is hoped that a better understanding of GRSs could achieve better clinical outcomes for the gingival retraction procedure
Nowakowska et al., 2020/Poland⁴³	Experimental Study/Experimental and Therapeutic Medicine	HGFs	Evaluation of collagen types I and III→ ImmunocytochemicalReactive oxygen Species→ dichlorofluorescein assayEvaluation of Fibronectin→ confocal laser scanning microscopy	Afrin (Schering-Plow)Visine classic (Pfizer)Starazolin (Polpharma)Neosynephrin POS 10% (Ursapharm)Injec. Adrenalini 0.05% (Self-prepared dilution of Injec. Adrenalini 0.01%, Polfa)Injec. Adrenalini 0.01% (Self-prepared dilution of Injec. Adrenalini 0.01%, Polfa)EG-1, EG-2 and EG-3 (Self-prepared)	The experimental gels are biocompatible with periodontal tissues and can be considered the new vasoconstrictive chemical retraction agents
Nowakowska et al., 2014/Poland⁴⁴	Experimental Study/Archives of oral Biology	HGFs	Cell preparation for lipid and protein oxidationMalondialdehyde Concentration→ Lipid peroxidation determinationProtein damage: Concentration of -SH groups→Ellman’s methodCells Survival→ Clonogenic assayExpression of manganese superoxide dismutase→ ImmunocytochemicalCytoskeletal Organization→ confocal laser scanning microscopy	Inject. Adrenalini 0.1% (Polfa, Warszawa, Poland)Inject. Adrenalini 0.01% (Self-made dilution of Injec. Adrenalini 0.1%)Inject. Adrenalini 0.05% (Self-made dilution of Injec. Adrenalini 0.1%)Visine® classic (Pfizer, Warsaw, Poland)Afrin® (Schering-Plough, Brussels, Belgium)Neosynephrin-POS® 10% (Ursaphamar, Saarbücken Germany)Starazolin® (Polpharma, Warsaw, Poland)Experimental gel 1 (self-made)Experimental gel 2 (self-made)Experimental gel 3 (self-made)	The classical retraction agents in the current concentration induce significant cytotoxic alterations in gingival fibroblast cells. The results indicate significantly lower cytotoxicity in gingival fibroblasts and less cellular damage after applying retraction agents in reduced concentrations and new formulas. The oxidative changes induced by the evaluated retraction agents were at the lowest safe level in the case of the experimental gels. The cytoskeleton observations suggest that the experimental agents did not degrade the cellular structure of HGFs
Cooper et al., 2013/New Zealand⁴⁵	Experimental Study/Brazilian oral Research	Fibroblast cell line (L929)	Surface chemistry of the titanium disks→ Energy-dispersive X-ray spectroscopy and laser ablation inductively coupled plasma mass spectrometryViability/Cytotoxicity→ confocal microscope	Gingival retraction paste (Expasyl®; Acteon, Bordeaux, France)	This in vitro study evaluated the effects of Expasyl paste on sterile titanium discs, simulating their interactions with dental implant surfacesIt was observed that discs previously exposed to this shrinkage agent showed fewer dead cells compared to non-exposed discs
Nowakowska et al., 2011/Poland⁴⁶	Experimental Study/Folia biologica	HGFs	Cell Viability→ MTT Asay	Inject. Adrenalini 0.1% (Polfa, Warszawa, Poland)Inject. Adrenalini 0.01% (Self-made dilution of Injec. Adrenalini 0.1%)Inject. Adrenalini 0.05% (Self-made dilution of Injec. Adrenalini 0.1%)Visine® classic (Pfizer, Warsaw, Poland)Afrin® (Schering-Plough, Brussels, Belgium)Neosynephrin-POS® 10% (Ursaphamar, Saarbücken Germany)Starazolin® (Polpharma, Warsaw, Poland)Experimental gel 1 (self-made)Experimental gel 2 (self-made)Experimental gel 3 (self-made)	High cell viability values of HGFs were observed after treatment with the self-fabricated gels based on 0.05% HCI-tetrahydrozoline. These agents can serve as a basis for future studies to select the best GRSs that are more biocompatible with the gingival margin tissues
Nowakowska et al., 2010/Poland⁴⁷	Experimental Study/Folia biologica	HGFs	Cell Viability→ MTT Asay	Aluminium chloridesGingiva Liquid (Roeko, Langenau, Germany)Alustin (Chema, Rzeszów, Poland)Alustat (Cerkamed, Nisko, Poland)Hemostat (Chema, Rzeszów, Poland)Racestypine (Septodont, Sain-Maur-des-fossés Cedex, France)Racécord (Septodont, Sain-Maur-des-fossés Cedex, France)Aluminium SulphatesOrbat sensitive (Lege artis, Germany)Gel cord (Pascal, Bellevue, WA)Ferric Sulphates: Astringedent® (Ultradent, South Jordan, UT)ViscoStat® (Ultradent, South Jordan, UT)	Ferric sulfate-based agents were the most cytotoxic, followed by aluminum chloride and aluminum sulfate. Under clinical conditions, the evaluated astringents may have cytotoxic potential for gingival margin tissues
Liu et al., 2004/Taiwan⁴⁸	Experimental Study/Journal of oral rehabilitation	HGFs	Cell Viability→ MTT Asay	Aluminum Sulphate (Gingi-Aid)DL-adrenaline HCI (Gingi-Pak)Non-drug-impregnated cord (Gingi-Plain*)	DL-adrenaline HCI-impregnated gingival retraction cord was the most toxic gingival retraction cord among the materials tested in all cultures
Kopac et al., 2002/Slovenia⁴⁹	Experimental Study/Journal of oral rehabilitation	HGFs	Cell Viability→ Colony forming ability test and MTT Asay	25% aluminium chloride, pH 0.8 (Racestyptine, Septodont, France)10% aluminum chloride, pH 1.8 (Gingiva Liquid, Roeko, Germany)20% aluminum sulfate, pH 2.6 (Rastringent, Pascal, USA)0.05% tetrahydrozoline, pH 5.6 (Visine, Pfizer, Canada)	The colony-forming capacity using the different GRSs tested revealed a higher number of colonies in samples treated with tetrahydrozoline. In addition, similar cytotoxic effects were observed for 25% aluminum sulfate and tetrahydrozoline

Table 5.

Summary of articles evaluating different gingival retraction systems on inflammatory cytokines levels.

Author (s)/Year/Country	Study type/Journal	Place/Subjects	Oral fluid/Detection method/Marker	Technique	Findings and conclusions
Mathew et al., 2022/India ⁵²	Clinical longitudinal Study/Journal of oral Biology and Craniofacial Research	Department of Prosthodontics at a dental School in KeralaTen male adults aged 20-40 years	60 teethGCFELISATNF-α	1.-Plain knitted gingival retraction cord2.-Expasyl retraction paste3.-Magic foam cordAt baseline, after 30 min, 7 days and 28 days	A maximum amount of inflammatory response was seen with the knitted gingival retraction cord. This was followed by Expasyl GRS, and the least amount of inflammatory cytokine was recorded with the magic foam retraction cord
Igic et al., 2019/Serbia ⁵³	Clinical longitudinal Study/Medical Principles and practice	Department of Prosthodontics at a dental School in BelgradeSixty adults of both sexes, aged 20-40 years	30 teethSalivaryELISAMCP-1	1.-25% AlCl3 (aluminium chloride)2.-15.5% Fe2(SO4)3 (ferric sulfate)Before (T0), 24 h (T1), and 72 h (T2) after the chemical-mechanical retraction procedure	The bleeding index values and the salivary concentration of MCP-1 increased statistically significantly after the chemical-mechanical GRS, with a tendency to decrease over time, which indicated the reversibility of the resulting changes. Higher values of the studied parameters were observed in the subjects with prepared teeth, and clinical changes were more pronounced after using ferric sulfate. However, no statistically significant difference was found
Feng et al., 2006/USA ⁵⁴	Clinical longitudinal Study/Journal of Prosthodontics	Institutional Research Board of the University of Medicine and Dentistry of New JerseySix adults of both sexes, aged 31-65	Ten teethGCFELISATNF-α	1.-Braided cords (Ultrapak knitted retraction cord, #0, Ultradent, Inc, South Jordan, UT)Baseline, day 1, 3, 7, 14 and 28	This study supports the previous research that GRS causes an acute injury that heals clinically in 2 weeks, as indicated by the GI. It also provides the first evidence that GRS results in an elevation of TNF-α levels in GCF.

Abbreviations: Gingival crevicular Fluid-GCF; enzyme-linked Inmmunosorbent Assay-ELISA; Tumor Necrosis factor Alpha-TNF-α; monocyte Chemotactic protein 1-MCP-1; Aluminium chloride- AlCl3; ferric sulfate- Fe2(SO4)3; gingival retraction systems- GRS.

Most of the studies were published in countries on the European continent (33.3%), and Asia (25%). The 37% of the articles were published in India, 18.5% in Poland, 7.4% in New Zealand and Germany, while the rest (3.7%) were from Pakistan, Brazil, Turkey, Egypt, Taiwan, Slovenia, Serbia and the United States.

The following were included in the studies presented: Sixteen (59.2%) correspond to studies evaluating the effects of different GRSs on the level of gingival displacement, eight (29.6%) correspond to studies evaluating the biological impact of HGFs exposed to various GRSs, and only three (11.1%) analyzed the influence of GRSs on the levels of inflammatory cytokines. Most studies were published after 2018 (20 studies: 74%). 11 articles (40.7%) were prospective randomized clinical studies, eight (29.6%) were retrospective randomized clinical studies, and another eight studies (29.6%) were in vitro experimental studies. The journals in which each of the studies included in the review were published are also summarized.

Synthesis of results

Few studies suffered from a lack of detail in their report, that is, they did not mention age, sex, number of teeth, and location. Concerning the clinical studies, it was found that 632 subjects participated in the 19 included articles, with an age range between 18 and 65 years.

Influence of the GRSs on the level of gingival displacement

Most studies (93.7%) evaluated periodontally healthy patients, and only one (6.3%) evaluated patients with mild gingivitis. Regarding the latter study,²⁷ the authors demonstrated that periodontal status did not influence gingival height for any of the gingival displacement methods employed. It was only found that the mild gingivitis model worsened the sulcus representation when the cord technique was used, but did not influence the sulcus representation of the paste technique. Also, a total of 882 teeth were sampled, of which the majority were posterior teeth including premolars and molars (54%), 33% were anterior teeth including central incisors, lateral incisors and canines, and 13% did not specify the type of tooth. The most commonly used GRSs was aluminum chloride gingival retraction paste (74%), followed by chemical-free gingival retraction cord (53%), polyvinyl siloxane (43.3%), polyvinyl acetate strips, Er, Cr: YSGG laser and ferric sulfate (11%), as well as polytetrafluoroethylene, naphazoline hydrochloride and tetrahydrozoline (5.3%). It was also found that the Merocel Strips system (Mystic, conn, USA) achieved the highest level of gingival displacement with a mean of 1.66 mm ,⁴⁰ while the Retraction Paste system (Expasyl, Pierre-Roland, Bordeaux, France) achieved the lowest level of gingival displacement with a mean of 0.4 mm.³⁶

Effect of GRSs on biological responses to HGFs

In this study, HGFs were the only cells evaluated (100%). The most commonly used technique was the MTT (3-(3,4 -dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) assay (50%) to measure cellular metabolic activity as an indicator of cell viability, proliferation, and cytotoxicity. This technique is followed by laser scanning confocal microscopy (37.5%) to assess the organization of the cytoskeleton. HGFs have been most frequently exposed to agents such as injection with 0.01 and 0.05% adrenaline (Self-made dilution of Injec. Adrenalini 0.1%), Visine® classic (Pfizer, Warsaw, Poland), Afrin® (Schering-Plough, Brussels, Belgium), Neosynephrin-POS® 10% (Ursaphamar, Saarbücken, Germany) and Starazolin® (Polpharma, Warsaw, Poland) (37.5%). In addition, astringent systems such as ferric sulfate produced higher toxicity in HGFs.

Inflammatory mediators production in GCF and saliva as a consequence of GRSs use

Two studies (67%) sampled gingival crevicular fluid (GCF), and only one study (33%) sampled saliva for the determination of inflammatory markers. In the three previously mentioned articles, the enzyme-linked immunosorbent assay (ELISA) was performed. In addition, the most frequently analyzed marker in GCF was TNF-α (67%), followed by MCP-1 (33%) which was only measured in saliva. Smooth knitted gingival retraction cord was found to maintain increased levels of TNF-α (16.08 ± 3.13 pg/mL) in GCF 28 days after the gingival displacement process; so far, the highest levels reported in the literature,⁵² whereas braided cords (Ultrapak knitted retraction cord, #0, Ultradent, Inc, South Jordan, UT) produced the lowest levels of this cytokine (0.43 ± 0.08pg/mL).⁵⁴ Figure 2 shows a summary of the main characteristics of the clinical studies.

Figure 2.

Periodontal condition, inflammatory mediators and gingival retractions systems evaluated in the present systematic review. Abbreviations: No information: NI, Gingival Crevicular Fluid: GCF; Enzyme-linked immunosorbent assay: ELISA; Tumor Necrosis Factor Alpha: TNF-α; Monocyte Chemotactic Protein 1: MCP-1; Aluminium Chloride: AlCl₃; Gingival Retraction Cord: GRC; Polyvinyl Siloxane: VPS; Polyvinyl Acetate Strips: PVA; láser Er,Cr: YSGG; Ferric Sulfate: Fe₂(SO₄)₃; Polytetrafluoroethylene: PTFE; naphazoline hydrochloride: NH.

Quality assessment of the selected studies

Tables 6, 7 and 8 show the data on the risk of bias in the selected studies according to the JBI and CONSORT tools. In general, randomized clinical trials had a low risk of bias,^23–41 whereas longitudinal and in vitro clinical studies ^{42–49,52–54} had a moderate risk of bias.

Table 6.

Results of the quality assessment of randomized controlled trials.

	Q1	Q2	Q3	Q4	Q5	Q6	Q7	Q8	Q9	Q10	Q11	Q12	Q13	%Y
Nasim et al²⁶	Y	Y	Y	Y	U	U	Y	Y	Y	Y	U	Y	Y	76
Kuhn et al²⁷	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Madaan et al²⁸	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Fernandes de Carvalho et al²⁹	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Kumari et al³⁰	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Değirmenci et al³¹	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Kuhn et al³²	Y	Y	Y	Y	Y	U	Y	Y	Y	Y	U	Y	Y	84
Rathod et al³³	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Qureshi et al³⁴	Y	Y	Y	Y	Y	U	Y	Y	Y	Y	U	Y	Y	84
Kavita et al³⁵	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Bennani et al³⁶	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Rayyan et al³⁷	Y	Y	Y	Y	U	Y	Y	Y	Y	Y	Y	Y	Y	92
Mehta et al³⁸	Y	Y	Y	Y	U	U	Y	Y	Y	Y	U	Y	Y	76
Gajbhiye et al³⁹	Y	Y	Y	Y	U	U	Y	Y	Y	Y	U	Y	Y	76
Thimmappa et al⁴⁰	Y	Y	Y	Y	U	U	Y	Y	Y	Y	Y	Y	Y	84
Goutham et al⁴¹	Y	Y	Y	Y	N	U	Y	Y	Y	Y	Y	Y	Y	92 Low

Question (Q); Y, yes; N, no; U, unclear N/A, not aplicable.

Q1:Was true randomization used for assigment of participants to treatment groups?

Q2: Was allocation to treatment groups concealed?

Q3: Were treatment groups similar at the baseline?

Q4: Were participants blind to treatment assignment?

Q5: Were those delivering treatment blind to treatment assigment?

Q6: Were outcomes assessors blind to treatment assignment?

Q7: Were treatment groups treated identically other than the intervention of interest?

Q8: Was follow up complete and if not, were differences between groups in terms of their follow up adequately described and analyzed?

Q9: Were participants analyzed in the groups to wich they were randomized?

Q10: Were outcomes measured in the same way for the treatment groups?

Q11: Were outcomes measured in a realible way?

Q12: Was appropriate statistical analysis used?

Q13: Was the trial design appropiate, and any deviations from the standard RCT design (individual randomization, parallel groups) accounted for in the conduct and analysis of the trial?

Table 7.

Results of the quality assessment of longitudinal studies.

	Q1	Q2	Q3	Q4	Q5	Q6	Q7	Q8	Q9	Q10	Q11	%Y
Mathew et al⁵²	Y	Y	U	Y	N	Y	Y	Y	N	N	Y	63
Igic et al⁵³	Y	Y	U	Y	N	Y	Y	N	N	N	Y	54
Feng et al⁵⁴	Y	Y	U	Y	N	Y	Y	Y	N	N	Y	63

Question (Q); Y, yes; N, no; U, unclear N/A, not aplicable.

Q1: Were two groups similar and recruited from the same population?

Q2: Were the exposures measured similary to assign people to both exposed and unexposed groups?

Q3: Was the exposure measured in a valid and reliable way?Q4: Were confounding factors identified?

Q5: Were strategies to deal with confounding factors stated?

Q6: Were the groups/participants free of the outcome at the start of the study (or at the momento of exposure)?

Q7: Were the outcomes measured in a valid and reliable?

Q8: Was the follow up time reported and sufficient to be long enough for outcomes to occur?

Q9: Was follow up complete, and if not, were the reasons to loss to follow up described and explored?

Q10: Were strategies to address incomplete follow up utilized?

Q11: Was appropriate statistical analysis used?

Table 8.

Results of the quality assessment of experimental studies.

Item	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	%Y
Nowakowska et al⁴²	Y	Y	Y	Y	N	N/A	N/A	N/A	N/A	Y	Y	Y	Y	Y	Y	67
Nowakowska et al⁴³	Y	Y	Y	Y	N	N/A	N/A	N/A	N/A	Y	Y	Y	Y	Y	Y	67
Nowakowska et al⁴⁴	Y	Y	Y	Y	N	N/A	N/A	N/A	N/A	Y	Y	Y	Y	Y	Y	67
Cooper et al⁴⁵	Y	Y	Y	Y	N	N/A	N/A	N/A	N/A	Y	Y	Y	Y	Y	Y	67
Nowakowska et al⁴⁶	Y	Y	Y	Y	N	N/A	N/A	N/A	N/A	Y	Y	Y	Y	Y	Y	67
Nowakowska et al⁴⁷	Y	Y	Y	Y	N	N/A	N/A	N/A	N/A	Y	Y	Y	Y	Y	Y	60
Liu et al⁴⁸	Y	Y	Y	Y	N	N/A	N/A	N/A	N/A	Y	Y	Y	Y	Y	Y	67
Kopac et al⁴⁹	Y	Y	Y	Y	N	N/A	N/A	N/A	N/A	Y	Y	Y	Y	Y	Y	67

Answer; Y, yes; N, no; U, unclear N/A, not aplicable.Items

1: Abstract

2: Introduction

3: Methods (Intervention)

4: Methods (Outcomes)

5: Methods (sample size)

6: Methods (Randomisation: Sequence generation)

7: Methods (Randomisation: Allocation concealment mechanism)

8: Methods (Randomisation: implementation)

9: Methods (Randomisation: blinding)

10: Statistical methods

11: Results (outcomes and estimation)

12: Discussion (limitations)

13: Other information (funding)

14: Other information (protocol)

Discussion

Periodontitis is an inflammatory and destructive disease affecting the teeth’ supporting tissues.⁵⁵ It is multifactorial and has a high prevalence worldwide, estimated at 62.3%.⁵⁶ One of the factors leading to its development is the use of prosthetic restorations with poor marginal and internal fit,⁵⁷ whose influence is preceded, in addition to other factors, by the use of a poor gingival displacement technique.¹⁷

In the clinic, it is not uncommon to find periodontal disease in the tooth at the time of gingival retraction and impression-taking.⁵⁸ This is the case in patients with poor oral hygiene or those who received a temporary fixed prosthesis before definitive prosthetic restoration and accumulated more dental bacterial plaque than usual, producing an inflammatory response.^59,60 A study²⁷ proved that, under the influence of mild gingivitis, better gingival displacement in the vertical direction was achieved when the aluminum chloride double cord technique was used before the conventional impression. On the other hand, Thimmappa et al., 2018 in their study showed that employing chemomechanical methods using Merocel Strips (Mystic, conn, USA) achieved a gingival displacement of 1.66 mm, optimal for excellent reproduction of the post-impression tooth preparation line. The Merocel strips system is a synthetic material chemically extracted from the polymer hydroxylated polyvinyl acetate. This biomaterial expands with the absorption of the GCF, exerting moderate pressure on the adjacent gingival tissue, thus ensuring gingival displacement. On the other hand, in our study we found that, according to the results of Bennani et al., 2020, the use of gingival retraction paste (Expasyl, Pierre-Roland, Bordeux, France) achieved the lowest level of displacement with a medium of 0.4 mm. These results are similar to those reported by Kazemi and Loran,⁶¹ who found greater gingival displacement with the use of cords presatured with AICI3, compared to Expasyl paste, however the latter caused less damage to the gingival tissues. In this sense, it has been shown that the GRS Expasyl, and Magic Foam Cord are two of the most biocompatible systems, as evaluated histologically, with respect to the periodontium.⁶² Furthermore, contrary to these results, another study showed that good gingival displacement can be achieved with the use of Expasyl paste.⁶³ The Expasyl system is effective, and atraumatic, its viscosity has been calculated to open the gingival sulcus effectively, without damaging the epithelial insertion. Additionally, it is an excellent tool for CAD/CAM, ensuring a clearer aperture for taking digital impressions. It has a fast, simple, and affordable protocol, without the need for additional anesthesia or homeostasis, and guarantees good performance, that is, it generates a pressure 1.7 to 9.2 times higher than other retraction compounds avaibles on the market, sufficiente to allow the opening of the sulcus .⁶⁴

Therefore, it remains a controversial topic, which is why it deserves more research. It is important to choose a biomaterial that can offer adequate displacement, but at the same time is not so harmful to periodontal tissues. The findings of the present systematic review will further help to identify retraction biomaterials that are viable, can be used safely, and guarantee minimal impact on the periodontal health of the tooth.⁶⁵

The antimicrobial properties of GRSs have been little investigated compared with the degree of gingival displacement and their effects on the periodontium.⁶⁶ During placement of different GRSs in the gingival sulcus, laceration with consequent tissue inflammation may occur, facilitating the penetration of microorganisms (bacteria, viruses, fungi, protozoa) through the junctional epithelium and then reaching deeper gingival tissues.^4,6,67 Therefore, a practical antimicrobial effect could reduce these complications.⁶⁸ It has been shown that systems such as Racestyptine, Retrax, Astringedent, and Astringedent X showed inhibitory activity against bacterial species such as Escherichia coli, Pseudomonas aeruginosa, Streptococcus gordonii, Streptococcus mitis and Streptococcus mutans, at the first and third minute of exposure, whereas, other agents (Hemodent) showed variable effects after 10 minutes. In addition, the most active systems reduced, but did not completely prevent, the metabolic activity of a monospecific biofilm. This study concluded that biofilm bacteria are less sensitive to the antimicrobial effects of the tested systems; however, more research is needed to clarify these observations in clinical practice.^69,70 It would be interesting to evaluate the effects of other GRSs on putative and recognized periodontopathogenic (Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) species (Campylobacter, Prevotella, and Fusobacterium species), as part of the bacterial species representative of gingivitis and periodontitis. For now, the clinician should be aware of the possible antimicrobial effects of some GRSs for use after tooth preparation and before conventional impression taking.

HGFs are essential cells in the periodontium⁷¹ because they are responsible, on the one hand, for modulating the immune response against periodontopathogenic bacteria that invade the gingival tissue by producing a wide variety of inflammatory mediators leading to inflammation and destruction, as occurs in periodontitis⁷² and on the other hand, the maintenance of tissue structure and integrity, since they produce most of the extracellular matrix, which is an essential aspect in the processes of repair, regeneration and wound healing.⁷³ Due to these properties, the biological response of HGFs after exposure to different GRSs is an essential scientific topic that requires detailed investigation.⁷⁴

It has been shown that different hemostatic agents based on aluminum chloride, aluminum sulfate, and ferric sulfate did not down-regulate HGF viability or proliferation and also did not show changes in cytoskeleton reorganization, except for Expasyl, which induced oxidative stress, demonstrated by increased nitrite level. Incubation with the previously mentioned agents significantly increased the RNA expression of some antioxidant enzymes such as SOD1, SOD3, and GPX1; however, no significant influence on the expression of SOD2 and HMOX1 was detected. The authors demonstrated that injectable forms of chemical retraction agents revealed biocompatibility with HGFs, suggesting their potential usefulness in the clinic for pre-impression gingival margin retraction.⁴² Another study demonstrated by MTT assay that ferric sulfate-based GRSs were the most cytotoxic, followed by aluminum chloride and aluminum sulfate.^45,48

On the other hand, vasoconstrictor-type agents such as α- and β-adrenergic solutions 0.05 and 0.01 epinephrine-HCI, 0.05% tetrahydrozoline-HCI, 0.05% oxymetazoline-HCI, 10% phenylephrine-HCI and three experimental gel formulations (EG-1, two and 3) based on 0.05% tetrahydrozoline-HCI, were used to treat HGFs. The experimental shrinkage gels did not limit the expression of type I and III collagen. GE-3 induced the synthesis of both types of collagen. An assay using the dichlorofluorescein fluorescent probe indicated oxidative stress similar to control cells for most of the selected retraction agents.⁴³ Another study published by the same working group found that the highest protein damage when using different chemical agents was observed in cells incubated with 0.1%, 0.01%, and 0.05% adrenaline. Also, they found a higher percentage of viable cells for HGFs incubated with the experimental gel n° 2, an increase in the expression of manganese dismutase superoxide enzymes in fibroblasts incubated with all GRSs and phenylephrine-HCI at 10% reduced the number of cells and abnormal rough actin appeared. Finally, they propose that the new 0.05% tetrahydrozoline-HCI-based gels are more biocompatible with periodontal tissues and can be applied as new chemo-mechanical vasoconstrictor-type GRSs.^44–49

Gingival retraction procedures can cause direct damage to keratinocytes and fibroblasts of the gingival tissue with consequent production of inflammatory cytokines and chemokines and immunoglobulins in oral fluids (GCF, saliva and serum), as well as an increase in the number of immune cells such as; neutrophils, macrophages, dendritic cells and B and T cells, which leads to structural changes in the tissue, that is, the inflammatory and destructive process is initiated.^6,75,76 It has been shown that using a single-point cord as a method of gingival retraction could modify some periodontal and inflammatory clinical parameters. On the one hand, it transiently increased the gingival index 1 day after its placement; however, it recovered to baseline at 14 days. On the other hand, TNF-α levels in GCF peaked on day one and then decreased in subsequent days; however, they were still elevated to 58% above baseline at day 28, suggesting persistence of the inflammatory state or a subclinical level of inflammation.⁵⁴ Similarly, in a clinical study published by Mathew et al., 2022 they compared the levels of TNF-α in GCF at three different times (30 min, 7 days, and 28 days) after gingival retraction by three methods by placing Expasyl retraction paste, Magic foam, and smooth point cord for identification of the least damaging system, they found that the minimum amount of inflammatory response was achieved with the Magic foam gingival retraction cord, where the levels of this cytokine reached almost baseline values in 28 days. The Expasyl retraction system, mainly through the use of the single stitch cord, increased TNF-α levels, nearly doubling at 28 days compared to baseline levels of this cytokine.

TNF-α is a proinflammatory and pleiotropic cytokine that serves different functions,⁶ including promotion of myeloid cells and suppression of osteoblastic activity through negative regulation of osteocalcin, alkaline phosphatase, and the transcription factor RUNX2, which prevents osteoblast differentiation. However, it can also inhibit the wnt signaling pathway, downregulating osteoblast function and increasing apoptosis. Also, TNF-α increases osteoclastic activity by up-regulating the expression of RANKL or by RANKL-independent autocrine/paracrine signaling, mechanisms that result in bone resorption.^72–74 Another vital function is the production of cytokines and chemokines, such as MCP-1/CCL2, a chemokine that attracts other immune cells to the site of injury, producing an inflammatory infiltrate that further perpetuates the inflammatory-destructive state of the periodontium.^75–77 In fact, it has been shown that the rate of gingival bleeding and MCP-1 levels increase after chemical-mechanical gingival retraction procedures, with a tendency to decrease over time. In this case, clinical and immunologic changes were more evident after using ferric sulfate, although these changes were not significant.⁵³

It is worth mentioning that, in fixed dental prostheses, 18 different inflammatory mediators have been identified to date, such as IL-1α, IL-1β, IL-6, IL-8, TNF-α, IL1ra, CRP, PGE2, MIP-1, IgG, CX3CL1, resistin, aspartate aminotransferase, alkaline phosphatase and matrix metalloproteases such as MMP-2, MMP-8, aMMP-8 and MMP-9 in GCF and blood serum with the primary purpose of knowing and evaluating the inflammatory response as a consequence of their use and thus, to determine which biomaterials produce a less harmful effect on the supporting tissues of the teeth, a fact that is very relevant to improve the success of prosthetic therapy. Therefore, these molecules induce and maintain the inflammatory response in the periodontium, creating a vicious circle that accelerates the pathogenesis of the disease.^6,78,79

To date, only three studies have been published that comparatively evaluate the effects produced by different gingival retraction systems (chemical-mechanical methods: Expasyl retraction paste, Magic foam, smooth point cord, single point, aluminum chloride, and ferric sulfate) on the amount of inflammation produced in response to TNF-α and MCP-1 levels in GCF and saliva. It would be fascinating to carry out future studies on the long-term effects of gingival retraction, with the use of other biomaterials and inflammatory mediators that show the dynamics of inflammation at the local level, that exert less damage to the periodontium and allow obtaining good results at the time of impression taking, all of the above to achieve the success of the prosthetic treatment.^80,81

Limitations

The present systematic review shows some limitations that reflect the high heterogeneity observed. With respect to the primary outcomes, it is important to highlight that some studies did not take into account clinically relevant factors such as the type of tooth where the GRS is used, ease of application, retraction time, costs, and possible complications such as the existence of tissue trauma, and gingival recessions. These factors must be taken into account when it comes to the selection of biomaterials or gingival retraction methods, therefore more controlled studies are needed where such comparisons can be made. With respect to the secondary outcomes, the biological activities of other cell types such as gingival keratinocytes, which also constitute an important part of the cells of the gingival sulcus, were not taken into account. Finally, with respect to the tertiary outcomes, the small sample sixe, the period of time recorded, the biological samples collectes, and the lack os analysis of other inflammatory mediators that reflect the dynamics of infla,,ation upon exposure to different GRSs must be taken into account in future studies to achieve more consistent and representative results.

Conclusions

With the limitations of the present study, three primary outcomes were evaluated: The amount of gingival displacement, the biological effects of HGFs, and the levels of inflammatory cytokines in response to the use of the different GRSs. Despite the heterogeneity of the results, the following conclusions were

• Molars and premolars were the teeth most frequently used to test GRSs.

• The GRS most used by the authors was a gingival retraction paste with aluminum chloride.

• The system: Merocel Strips (Mystic, conn, USA) achieved the highest level of gingival displacement (1.66 ± 3.7 mm), while the retraction paste system (Expasyl, Pierre-Roland, Bordeaux, France) achieved the lowest level of gingival displacement with a mean of 0.4 mm.

• Astringent systems such as ferric sulfate produce more significant toxicity in HGFs. The experimental gels based on 0.05% HCI-tetrahydrozoline in different dilutions (1:10 and 1:20) are biocompatible with periodontal tissues and can be considered as new chemical gingival retraction vasocontrictor agents.

• The most frequently analyzed biomarker was TNF-α in GCF. In addition, smooth knitted gingival retraction cord was found to maintain increased levels of TNF-α (16.08 ± 3.13 pg/mL) in GCF 28 days after the gingival displacement process, while braided cords (Ultrapak Knitted retraction cord, #0, Ultradent, Inc, South Jordan, UT) produce the lowest levels of this cytokine (0.43 ± 0.08pg/mL).

We encourage continuing to carry out randomized controlled trials of high-quality in vivo and in vitro studies to generate sufficient data to find the appropriate GRSs with less harmful effects on the periodontium but at the same time achieving good levels of gingival displacement, which will allow a better impression of the dental preparation line. An exact reproduction of this anatomical structure, in combination with the use of CAD/CAM technology, will generate better prosthetic devices.

Footnotes

Author contributions

Mario Alberto Alarcón-Sánchez: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Resources, Data Curation, Writing - Original Draft, Writing - Review and editing, Visualization, Supervision, Project administration. Artak Heboyan: Formal analysis, Writing - Review & Editing, Project administration. Giuseppe Minervini: Formal analysis, Writing - Review & Editing, Project administration.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Artak Heboyan

Data availability statement

The data supporting this study’s findings are available from the corresponding author upon reasonable request.

Appendix

References

Avetisyan

Markaryan

Rokaya

, et al. Characteristics of periodontal tissues in prosthetic treatment with fixed dental prostheses. Molecules 2021; 2: 1331.

Sailer

Karasan

Todorovic

, et al. Prosthetic failures in dental implant therapy. Periodontol 2000; 88(1): 130–144. DOI: 10.1111/prd.12416

Verma

Singh

Arya

, et al. Mechanical failures of dental implants and supported prostheses: a systematic review. J Oral Biol Craniofac Res. 2023; 13(2): 306–314. DOI: 10.1016/j.jobcr.2023.02.009

Heboyan

Zafar

Khurshid

, et al. Fixed prosthetic restorations and periodontal health: a narrative review. J Funct Biomater 2022; 13: 15.

Eggmann

Ayub

Conejo

, et al. Deep margin elevation-Present status and future directions. J Esthetic Restor Dent 2023; 35(1): 26–47. DOI: 10.1111/jerd.13008

Alarcón-Sánchez

Heboyan

Fernandes

GVO

, et al. Potential impact of prosthetic biomaterials on the periodontium: a comprehensive review. Molecules 2023; 28: 1075.

Ercoli

Tarnow

Poggio

, et al. The relationships between tooth supported fixed dental prostheses and restorations and the periodontium. J Prosthodont 2021; 30: 305–317.

Ashtiani

Alam

Tavakolizadeh

, et al. The role of biomaterials and biocompatible materials in implant-supported dental prosthesis. Evidence-based complement. Alternative Med; 202: 3349433.

Afshari

Mosaddad

Alam

, et al. Biomaterials and biological parameters for fixed-prosthetic implant-supported restorations: a review study. Adv Mater Sci Eng 2022; 22: 1–16.

10.

D'Ambrosio

Santella

Di Palo

, et al. Characterization of the oral microbiome in wearers of fixed and removable implant or non-implant-supported prostheses in healthy and pathological oral conditions: a narrative review. Microorganisms 2023;11(4):1041. DOI: 10.3390/microorganisms11041041

11.

Huang

Somar

, et al. Efficiency of cordless versus cord techniques of gingival retraction: a systematic review. J Prosthodont 2017; 26(3): 177–185. DOI: 10.1111/jopr.12352

12.

Sorrentino

Ruggiero

Zarone

. Laser systems for gingival retraction in fixed prosthodontics: a narrative review. J Osseointegr 2022; 14(1): 1–5.

13.

Heboyan

Muradyan

. Impression material selection and SoftTissue management in contemporary fixed prosthodontics. International Academy Journal Web of Scholar 2019; 5(35). DOI: 10.31435/rsglobal_wos/31052019/6499

14.

Rokaya

Bohara

Srimaneepong

, et al. Metallic biomaterials for medical and dental prosthetic applications. In: Jana

(ed). Functional Biomaterials. Singapore: Springer, 2022.

15.

Nowakowska

Saczko

Kulbacka

, et al. Chemical retraction agents - in vivo and in vitro studies into their physico-chemical properties, biocompatibility with gingival margin tissues and compatibility with elastomer impression materials. Mini Rev Med Chem 2017; 17(5): 435–444. DOI: 10.2174/1389557516666160418122701

16.

Kazakova

Vlahova

Tomov

, et al. A comparative analysis of post-retraction changes in gingival height after conventional and surgical gingival displacement: rotary curettage, diode and Er:YAG laser troughing. Healthcare (Basel) 2023;11(16):2262. DOI: 10.3390/healthcare11162262

17.

Martins

Santana

Fonseca

. Efficacy of conventional cord versus cordless techniques for gingival displacement: a systematic review and meta-analysis. J Prosthet Dent 2021; 125(1): 46–55. DOI: 10.1016/j.prosdent.2019.09.009

18.

Sarafidou

Chatziparaskeva

Chatzikamagiannis

, et al. Evaluation of marginal/internal fit of fixed dental prostheses after digital, conventional, and combination impression techniques: a systematic review. Eur J Oral Sci 2022; 130(6): e12902. DOI: 10.1111/eos.12902

19.

. Gingival retraction methods for fabrication of fixed partial denture: literature review. J Dent Biomater 2016; 3(2): 205–213.

20.

Dederichs

Fahmy

Kuepper

, et al. Comparison of gingival retraction materials using a new gingival sulcus model. J Prosthodont 2019; 28(7): 784–789. DOI: 10.1111/jopr.13093

21.

Donovan

Gandara

Nemetz

. Review and survey of medicaments used with gingival retraction cords. J Prosthet Dent 1985; 53(4): 525–531. DOI: 10.1016/0022-3913(85)90640-7

22.

Ahmed

Donovan

. Gingival displacement: survey results of dentists' practice procedures. J Prosthet Dent 2015; 114(1): 81–85. DOI: 10.1016/j.prosdent.2014.11.015

23.

Phatale

Marawar

Byakod

, et al. Effect of retraction materials on gingival health: a histopathological study. J Indian Soc Periodontol 2010; 14(1): 35–39. DOI: 10.4103/0972-124X.65436

24.

Shivasakthy

Asharaf Ali

. Comparative study on the efficacy of gingival retraction using polyvinyl acetate strips and conventional retraction cord - an in vivo study. J Clin Diagn Res 2013; 7(10): 2368–2371. DOI: 10.7860/JCDR/2013/6980.3526

25.

Chaudhari

Prajapati

Patel

, et al. Comparative evaluation of the amount of gingival displacement produced by three different gingival retraction systems: an in vivo study. Contemp Clin Dent 2015; 6(2): 189–195. DOI: 10.4103/0976-237X.156043

26.

Nasim

Lone

Kumar

, et al. Evaluation of gingival displacement, bleeding and ease of application for polytetrafluoroethylene (PTFE) and conventional retraction cord - a clinical trial. Eur Rev Med Pharmacol Sci 2023; 27(6): 2222–2231. DOI: 10.26355/eurrev_202303_31756

27.

Kuhn

Zügel

Korbay

, et al. Gingival displacement in the vertical and horizontal dimension under the condition of mild gingivitis-A randomized clinical study. J Clin Med 2022; 11(2): 437. DOI: 10.3390/jcm11020437

28.

Madaan

Paliwal

Sharma

, et al. Comparative evaluation of the clinical efficacy of four different gingival retraction systems: an in vivo study. Cureus 2022; 14(4): e23923. DOI: 10.7759/cureus.23923

29.

de Carvalho

Junior

LCV

Junior

HFB

, et al. Evaluation of gingival displacement with aluminum chloride and naphazoline hydrochloride: a randomized controlled trial. Eur J Prosthodont Restor Dent 2021; 29(1): 47–53. DOI: 10.1922/EJPRD_2066Junior10

30.

Kumari

Singh

Parmar

, et al. Evaluation of effectiveness of three new gingival retraction systems: a comparative study. J Contemp Dent Pract 2021; 22(8): 922–927.

31.

Ünalan Değirmenci

Karadağ Naldemir

Değirmenci

. Evaluation of gingival displacement methods in terms of periodontal health at crown restorations produced by digital scan: 1-year clinical follow-up. Laser Med Sci 2021; 36(6): 1323–1335. DOI: 10.1007/s10103-021-03266-5

32.

Kuhn

Rudolph

Zügel

, et al. Influence of the gingival condition on the performance of different gingival displacement methods-A randomized clinical study. J Clin Med 2021; 10(13): 2747. DOI: 10.3390/jcm10132747

33.

Rathod

Jacob

Malqahtani

, et al. Efficacy of different gingival displacement materials in the management of gingival sulcus width: a comparative study. J Contemp Dent Pract 2021; 22(6): 703–706.

34.

Qureshi

Anasane

Kakade

. Comparative evaluation of the amount of gingival displacement using three recent gingival retraction systems - In vivo study. Contemp Clin Dent 2020; 11(1): 28–33. DOI: 10.4103/ccd.ccd_311_19

35.

Kavita

Sinha

Singh

, et al. Assessment of aluminum chloride retraction cords, Expasyl, and tetrahydrozoline-soaked retraction systems in gingival retraction. J Pharm BioAllied Sci 2020; 12(Suppl 1): S440–S443. DOI: 10.4103/jpbs.JPBS_131_20

36.

Bennani

Aarts

Brunton

. A randomized controlled clinical trial comparing the use of displacement cords and aluminum chloride paste. J Esthetic Restor Dent 2020; 32(4): 410–415. DOI: 10.1111/jerd.12581

37.

Rayyan

Hussien

ANM

Sayed

, et al. Comparison of four cordless gingival displacement systems: a clinical study. J Prosthet Dent 2019; 121(2): 265–270. DOI: 10.1016/j.prosdent.2018.05.010

38.

Mehta

Virani

Memon

, et al. A comparative evaluation of efficacy of gingival retraction using polyvinyl siloxane foam retraction system, vinyl polysiloxane paste retraction system, and copper wire reinforced retraction cord in endodontically treated teeth: an in vivo study. Contemp Clin Dent 2019; 10(3): 428–432. DOI: 10.4103/ccd.ccd_708_18

39.

Gajbhiye

Banerjee

Jaiswal

, et al. Comparative evaluation of three gingival displacement materials for efficacy in tissue management and dimensional accuracy. J Indian Prosthodont Soc 2019; 19(2): 173–179. DOI: 10.4103/jips.jips_285_18

40.

Thimmappa

Bhatia

Somani

, et al. Comparative evaluation of three noninvasive gingival displacement systems: an in vivo study. J Indian Prosthodont Soc 2018; 18(2): 122–130. DOI: 10.4103/jips.jips_225_17

41.

Goutham

Jayanti

Jalaluddin

, et al. Clinical assessment of gingival sulcus width using various gingival displacement materials. J Contemp Dent Pract 2018; 19(5): 502–506.

42.

Nowakowska

Kulbacka

Wezgowiec

, et al. Biological response induced in primary human gingival fibroblasts upon exposure to various types of injectable astringent retraction agents. Materials 2021;14(8):2081. DOI: 10.3390/ma14082081

43.

Nowakowska

Saczko

Szewczyk

, et al. In vitro effects of vasoconstrictive retraction agents on primary human gingival fibroblasts. Exp Ther Med 2020; 19(3): 2037–2044. DOI: 10.3892/etm.2020.8462

44.

Nowakowska

Saczko

Bieżuńska-Kusiak

, et al. The influence of retraction agents on cytoskeleton reorganization and oxidative stress in primary human gingival fibroblasts (HGFs). Arch Oral Biol 2014; 59(3): 341–348. DOI: 10.1016/j.archoralbio.2013.12.011

45.

Cooper

Bennani

Tawse-Smith

, et al. Effect of a cordless retraction paste on titanium surface: a topographic, chemical and biocompatibility evaluation. Braz Oral Res 2013; 27(3): 211–217. DOI: 10.1590/S1806-83242013000300002

46.

Nowakowska

Saczko

Kulbacka

, et al. Cytotoxic potential of vasoconstrictor experimental gingival retraction agents: in vitro study on primary human gingival fibroblasts. Folia Biol 2012; 58(1): 37–43.

47.

Nowakowska

Saczko

Kulbacka

, et al. Dynamic oxidoreductive potential of astringent retraction agents. Folia Biol 2010; 56(6): 263–268.

48.

Liu

Huang

Yang

, et al. Cytotoxic effects of gingival retraction cords on human gingival fibroblasts in vitro. J Oral Rehabil 2004; 31(4): 368–372. DOI: 10.1046/j.1365-2842.2003.01237.x

49.

Feng

Aboyoussef

Weiner

, et al. The effect of gingival retraction procedures on periodontal indices and crevicular fluid cytokine levels: a pilot study. J Prosthodont 2006; 15(2): 108–112. DOI: 10.1111/j.1532-849X.2006.00083.x

50.

Page

McKenzie

Bossuyt

, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021; n71.

51.

Kopac

Batista

Cvetko

Marion

. Viability of fibroblasts in cell culture after treatment with different chemical retraction agents. J Oral Rehabil 2002; 29(1): 98–104. DOI: 10.1046/j.1365-2842.2002.00790.x

52.

Mathew

Saranya

Mohan

. Estimation of cytokine levels in gingival crevicular fluid following the use of different gingival retraction systems in patients requiring fixed partial dentures - an original research. J Oral Biol Craniofac Res 2022; 12(5): 709–712. DOI: 10.1016/j.jobcr.2022.08.014

53.

Igic

Kostic

Basic

Krunic

Pejcic

Gligorijevic

Milic Lemic

. Bleeding index and monocyte chemoattractant protein 1 as gingival inflammation parameters after chemical-mechanical retraction procedure. Med Princ Pract 2020;29(5):492–498. DOI: 10.1159/000506878

54.

Nuñez-Belmar

Morales-Olavarria

Vicencio

, et al. Contribution of −Omics technologies in the study of porphyromonas gingivalis during periodontitis pathogenesis: a minireview. Int J Mol Sci 2023; 24: 620.

55.

Faggion

. Guidelines for reporting pre-clinical in vitro studies on dental materials. J Evid Base Dent Pract 2012; 12(4): 182–189. DOI: 10.1016/j.jebdp.2012.10.001

56.

Trindade

Carvalho

Machado

Chambrone

Mendes

Botelho

. Prevalence of periodontitis in dentate people between 2011 and 2020: a systematic review and meta-analysis of epidemiological studies. J Clin Periodontol 2023; 50(5): 604–626.

57.

Heboyan

. Marginal and internal fit of fixed prosthodontic constructions: a literature review. IJDRR 2019; 2: 19.

58.

Kumar

Mattoo

Jain

Khalid

Kota

Baig

FAH

Ibrahim

Javali

Khader

Kanji

. A clinical study of 50 partially edentulous patients with fixed partial denture restorations to compare clinical parameters and changes in gingival sulcus width after displacement with 2 different gingival retraction cord materials (cotton and polymer). Med Sci Mon Int Med J Exp Clin Res2023; 29: e940098. DOI: 10.12659/MSM.940098

59.

Passariello

Puttini

Virga

, et al. Microbiological and host factors are involved in promoting the periodontal failure of metaloceramic crowns. Clin Oral Invest 2012; 16: 987–995.

60.

Kazemi

MMM

Loran

. Comparing the effectiveness of two gingival retraction procedures on gingival recession and tissue displacement: clinical study. Aust J Biol Sci 2009; 4: 335–339.

61.

Prasanna

Reddy

Kumar

, et al. Evaluation of effi cacy of different gingival displacement materials on gingival sulcus width. J Contemp Dent Pract 2013; 14: 217–221.

62.

Alraheam

Hattar

Al-Asmar

, et al. Dentists' knowledge and preference regarding gingival displacement methods. BMC Oral Health 2023; 23(1): 574. DOI: 10.1186/s12903-023-03218-1

63.

Heboyan

Manrikyan

Zafar

, et al. Bacteriological evaluation of gingival crevicular fluid in teeth restored using fixed dental prostheses: an in vivo study. Int J Mol Sci 2021; 22: 5463.

64.

Rice

Dykstra

Gier

. Bacterial contamination in irreversible hydrocolloid impression material and gingival retraction cord. J Prosthet Dent 1991; 65(4): 496–499. DOI: 10.1016/0022-3913(91)90287-7

65.

Esparbès

Legrand

Bandiaky

, et al. Subgingival microbiota and cytokines profile changes in patients with periodontitis: a pilot study comparing healthy and diseased sites in the same oral cavities. Microorganisms 2021; 9: 2364.

66.

Herrera

Alonso

León

, et al. Antimicrobial therapy in periodontitis: the use of systemic antimicrobials against the subgingival biofilm. J Clin Periodontol 2008; 35(8 Suppl): 45–66. DOI: 10.1111/j.1600-051X.2008.01260.x

67.

Hsu

Lee

Schwass

, et al. Antimicrobial activity of chemomechanical gingival retraction products. J Am Dent Assoc 2017; 148(7): 493–499. DOI: 10.1016/j.adaj.2017.03.006

68.

Serrano-Lopez

Morandini

. Fibroblasts at the curtain call: from ensemble to principal dancers in immunometabolism and inflammaging. J Appl Oral Sci 2023; 31: e20230050. DOI: 10.1590/1678-7757-2023-0050

69.

Zhao

Quan

Lei

, et al. The role of inflammasome NLPR3 in the development and therapy of periodontitis. Int J Med Sci 2022; 19(10): 1603–1614. DOI: 10.7150/ijms.74575

70.

Talbott

Mascharak

Griffin

, et al. Wound healing, fibroblast heterogeneity, and fibrosis. Cell Stem Cell 2022; 29(8): 1161–1180. DOI: 10.1016/j.stem.2022.07.006

71.

Wielento

Lagosz-Cwik

Potempa

, et al. The role of gingival fibroblasts in the pathogenesis of periodontitis. J Dent Res 2023; 102(5): 489–496. DOI: 10.1177/00220345231151921

72.

Becerra-Ruiz

Guerrero-Velázquez

Martínez-Esquivias

, et al. Innate and adaptative immunity of periodontal disease. From etiology to alveolar bone loss. Oral Dis 2021; 6: 1441–1447.

73.

Pan

Wang

Chen

. The cytokine network involved in the host immune response to periodontitis. Int J Oral Sci 2019; 3: 30.

74.

AlQranei

Chellaiah

. Osteoclastogenesis in periodontal diseases: possible mediators and mechanisms. J Oral Biosci 2020; 62(2): 123–130. DOI: 10.1016/j.job.2020.02.002

75.

Sadek

El Moshy

Radwan

, et al. Molecular basis beyond interrelated bone resorption/regeneration in periodontal diseases: a concise review. Int J Mol Sci 2023; 24(5): 4599. DOI: 10.3390/ijms24054599

76.

Zhang

Song

Kwon

, et al. Pirfenidone inhibits alveolar bone loss in ligature-induced periodontitis by suppressing the NF-κB signaling pathway in mice. Int J Mol Sci 2023; 24(10): 8682. DOI: 10.3390/ijms24108682

77.

Boström

Kindstedt

Sulniute

, et al. Increased eotaxin and MCP-1 levels in serum from individuals with periodontitis and in human gingival fibroblasts exposed to pro-inflammatory cytokines. PLoS One 2015; 10(8): e0134608. DOI: 10.1371/journal.pone.0134608

78.

Nisha

Suresh

Anilkumar

, et al. MIP-1α and MCP-1 as salivary biomarkers in periodontal disease. Saudi Dent J 2018; 30(4): 292–298. DOI: 10.1016/j.sdentj.2018.07.002

79.

Gupta

Chaturvedi

Jain

. Role of monocyte chemoattractant protein-1 (MCP-1) as an immune-diagnostic biomarker in the pathogenesis of chronic periodontal disease. Cytokine 2013; 61(3): 892–897. DOI: 10.1016/j.cyto.2012.12.012

80.

Rajagopal

Chander

Anitha

, et al. Evaluation of psychological stress marker in partially edentulous Indian adults restored with fixed dental prosthesis - a prospective cohort study. Contemp Clin Dent 2020; 11(2): 116–120. DOI: 10.4103/ccd.ccd_63_20

81.

Dragomir

Nicolae

Gheorghe

, et al. The influence of fixed dental prostheses on the expression of inflammatory markers and periodontal status-narrative review. Medicina 2023;59(5):941. DOI: 10.3390/medicina59050941

Clinical and immunological aspects of gingival retraction systems in fixed dental prostheses: A systematic review

Abstract

Objective

Methods

Results

Conclusion

Keywords

Introduction

Materials and methods

Review question

Eligibility criteria

Electronic search

Manual search

Search strategy

Methods of detection and data extraction

Outcome measures

Inclusion of evidence sources

Quality assessment of the selected studies

Result

Study selection and characteristics

Synthesis of results

Influence of the GRSs on the level of gingival displacement

Effect of GRSs on biological responses to HGFs

Inflammatory mediators production in GCF and saliva as a consequence of GRSs use

Quality assessment of the selected studies

Discussion

Limitations

Conclusions

Footnotes

Author contributions

Declaration of conflicting interests

Funding

ORCID iD

Data availability statement

Appendix

References