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OBJECTIVE: Conventional use of retraction cord in soft tissue management is effective only when the non-resilient nature of material does not jeopardize gingival health. Therefore this study aims to clinically evaluate the gingival displacement, ease of application and bleeding from polytetrafluoroethylene (PTFE) retraction cord. PATIENTS AND METHODS: This study is a single-center, parallel-group, randomized controlled clinical trial (1:1). Sixty patients indicated for full coverage metal-ceramic restoration for first molars were enrolled and randomly allocated to experimental (PTFE Cord) and control (conventional plain retraction cord) groups. After crown preparation and isolation, a pre-displacement impression was made. Assigned gingival displacement material was applied for 5 minutes, followed by post-displacement impression. Casts were prepared and used for assessment of mean horizontal gingival displacement by measuring displacement using a stereomicroscope (20 x). Post-displacement gingival bleeding and ease of application were also assessed clinically. t-test and Chi-square tests were used for statistical assessment of gingival displacement, gingival bleeding and ease of application. RESULTS: Gingival displacement, bleeding and ease of application were similar among study groups (p > 0.05). Mean gingival displacement in the experimental group was 197.1 µm, and 167.7 µm in the control group. Bleeding was observed in 30% and 20% of cases of experimental and control group, respectively. Ease of application was 'difficult' in 53.3% and 43.3% of cases of experimental and control group, respectively. Non-impregnated gingival retraction cord and PTFE cord displayed similar outcomes of gingival displacement, ease of placement and bleeding after cord removal. CONCLUSIONS: Post-displacement bleeding and discomfort for PTFE cord placement suggest that this technique needs improvement. Therefore further studies are warranted to improve and investigate the physical and biological response to PTFE retraction cord. [ABSTRACT FROM AUTHOR]

Objective: To assess the self-perceived pain perception (PP) and whole salivary cortisol levels (CL) among adolescents with and without temporomandibular disorders (TMD)., Methods: Adolescents between 15 and 17 years were included. Participants were categorized into three groups: Group 1: patients with TMD; Group 2: nocturnalbruxers without TMD; and Group 3: controls. Demographic data CL and self-rated PP were assessed. A p -value < 0.05 was proposed as statistically significant., Results: Fifty-four patients (18 per group) were included. Scores of self-rated PP in the affected TMJ were higher in Group 1 than Group 2 ( p < 0.001). Whole salivary CL were higher in groups 1 and 2 ( p < 0.01) than in Group 3. Whole salivary CL were higher in Group 2 than Group 3 ( p < 0.05)., Conclusion: Whole salivary CL are higher in adolescents with TMD, and there is a direct relationship between self-rated PP in the TMJ area and salivary CL.

Background and Objective: This study aimed to compare the surface finish of milled leucite-reinforced ceramics polished with ceramic and composite polishing systems based on the manufacturers' recommendations. Materials and Methods: Sixty subtractive computer-aided manufactured (s-CAM) leucite-reinforced glass-ceramic specimens (IPS-Empress-CAD) were assigned into six groups: no polishing, a ceramic polishing kit, and four composite kit groups. The roughness average (Ra) was evaluated in microns using a profilometer, and scanning electron micrographs were obtained for qualitative analysis. A Tukey HSD posthoc test (α = 0.05) was used to determine significant intergroup differences. Results: After surface evaluation of the ceramics, the Ra values of the polishing systems ranked OptraFine (0.41 ± 0.26) < Enhance (1.60 ± 0.54) < Shofu (2.14 ± 0.44) < Astropol (4.05 ± 0.72) < DiaComp (5.66 ± 0.62) < No Polishing (5.66 ± 0.74). Discussion: Composite polishing systems did not provide as smooth surfaces as the ceramic polishing kit for CAD-CAM leucite-reinforced ceramics. Thus, using ceramic polishing systems, polishing leucite ceramics is recommended, whereas composite polishing systems should not be considered as an alternative for use in minimally invasive dentistry.

Objective: Conventional use of retraction cord in soft tissue management is effective only when the non-resilient nature of material does not jeopardize gingival health. Therefore this study aims to clinically evaluate the gingival displacement, ease of application and bleeding from polytetrafluoroethylene (PTFE) retraction cord., Patients and Methods: This study is a single-center, parallel-group, randomized controlled clinical trial (1:1). Sixty patients indicated for full coverage metal-ceramic restoration for first molars were enrolled and randomly allocated to experimental (PTFE Cord) and control (conventional plain retraction cord) groups. After crown preparation and isolation, a pre-displacement impression was made. Assigned gingival displacement material was applied for 5 minutes, followed by post-displacement impression. Casts were prepared and used for assessment of mean horizontal gingival displacement by measuring displacement using a stereomicroscope (20 x). Post-displacement gingival bleeding and ease of application were also assessed clinically. t-test and Chi-square tests were used for statistical assessment of gingival displacement, gingival bleeding and ease of application., Results: Gingival displacement, bleeding and ease of application were similar among study groups (p > 0.05). Mean gingival displacement in the experimental group was 197.1 µm, and 167.7 µm in the control group. Bleeding was observed in 30% and 20% of cases of experimental and control group, respectively. Ease of application was 'difficult' in 53.3% and 43.3% of cases of experimental and control group, respectively. Non-impregnated gingival retraction cord and PTFE cord displayed similar outcomes of gingival displacement, ease of placement and bleeding after cord removal., Conclusions: Post-displacement bleeding and discomfort for PTFE cord placement suggest that this technique needs improvement. Therefore further studies are warranted to improve and investigate the physical and biological response to PTFE retraction cord.

Objective: To investigate the efficacy of three specially designed polishing kits for provisional restorations made from three chairside computer-aided design and computer-aided manufacturing (CAD/CAM) provisional resin blocks., Method: Ninety-six chairside CAD/CAM provisional restorations were milled out of three chairside CAD/CAM provisional resin blocks: (1) ArtBloc Temp (Merz Dental); (2) Telio CAD (Ivoclar Vivadent); and (3) Vita CAD-Temp (VITA Zahnfabrik). The provisional restorations for each material were allocated into the following groups: (1) milled restorations (no polish); (2) polished with CADMaster CAD/CAM Adjustment & Polishing Kit (CM, Shofu); (3) polished with KUT Ultimate Bisacryl (Temporaries) Polishing Kit (KU, Dental Savings Club); and (4) polished with K0330 PMMA Adjusting, Finishing & Polishing (KP, Brasseler USA). Optical profilometry and atomic force microscopy (AFM) were used to assess the surface roughness (Ra) of each provisional restoration at the microscale and nanoscale, respectively, and obtain topographical images. In addition, the milled and polished restorations were visually evaluated by 16 dentists., Results: There was a strong positive correlation with Ra values between optical profilometry and AFM. Only KP significantly improved the surface roughness of CAD/CAM provisional restorations compared to the milled equivalent, regardless of material type or measurement modality (ie, lateral length scale). Although surface topography imaging with AFM revealed some shallow scratches, even for KP polished specimens, all KP polished restorations were categorized as clinically acceptable for provisional restorations in visual inspections from dentists., Conclusion: Specially designed polishing kits for provisional restorations did not all improve the surface roughness of chairside CAD/CAM provisional restorations, regardless of the measurement method. KP was more consistently effective in polishing milled chairside CAD/CAM provisional restorations than CM and KU., (©Operative Dentistry, 2022.)

It is hypothesized that under optimal glycemic control (GC), there is no difference in the survival of implants placed in the zygomatic bone of edentulous patient with and without type 2 diabetes mellitus (T2DM). The aim was to assess the influence of GC on survival of implants placed in the zygomatic bone of an edentulous patient with and without T2DM at the 10-year follow-up. Twenty patients with T2DM (10 with poorly controlled T2DM and 10 with well-controlled T2DM) and 12 patients without T2DM were included. Hemoglobin A1c (HbA1c) levels were recorded, and demographic data were collected from all participants. Peri-implant inflammatory parameters (plaque index [PI], probing depth [PD], crestal bone loss [BL], and gingival index [GI]) were measured in all patients. Group comparisons were done, and P values, which were less than .01, were indicative of statistical significance. Twenty and 12 male patients with and without T2DM, respectively, were included. Among patients with T2DM, 10 and 10 individuals had poorly and well-controlled T2DM, respectively. The mean HbA1c levels were significantly higher in patients with poorly controlled T2DM (9.2 ± 0.7%) compared with well-controlled T2DM (4.8 ± 0.3%; P < .01) and nondiabetic individuals (4.6 ± 0.3%; P < .01). The crestal BL on the mesial (P < .01) and distal (P < .01) surfaces, PD (P < .01), PI (P < .01), and GI (P < .01) were significantly higher around all zygoma implants placed in patients with poorly controlled T2DM compared with patients with well-controlled T2DM and patients without T2DM. These clinicoradiographic parameters were comparable around zygoma implants placed in patient with well-controlled T2DM and in subjects without T2DM. Optimal GC is essential for the long-term stability of zygomatic plants in patients with T2DM.

Aim: To evaluate light transmission in a novel chairside CAD/CAM lithium disilicate ceramic with different thicknesses and with and without polishing., Materials and Methods: Sixty flat samples (10 specimens/group) were fabricated from novel chairside CAD/CAM lithium disilicate ceramic blocks (Amber Mill, Hass Bio) with different thicknesses and with and without polishing as follows: (1) 1.0 mm thickness without polishing (1.0NoP); (2) 1.0 mm thickness with polishing (1.0Po); (3) 1.5 mm thickness without polishing (1.5NoP); (4) 1.5 mm thickness with polishing (1.5Po); (5) 2.0 mm thickness without polishing (2.0NoP); and (6) 2.0 mm thickness with polishing (2.0Po). Specimens were polished with a polishing system for lithium disilicate restorations following the manufacturer's recommendations. Light transmission was evaluated with a curing radiometer. Obtained data were subjected to two-way ANOVA followed by Tukey's post hoc tests (α = 0.05). SEM observations were conducted to evaluate surface microstructure., Results: The light intensity through the lithium disilicate blocks with and without polishing was 200.9 mW/cm 2 (16.1%) and 194.4 mW/cm 2 (15.6%) for 1.0 mm specimens, 119.3 mW/cm 2 (9.5%) and 111.9 mW/cm 2 (9.0%) for 1.5 mm specimens, and 102.3 mW/cm 2 (8.2%) and 96.0 mW/cm 2 (7.7%) for 2.0 mm specimens. SEM images showed a smoother surface with polishing compared to nonpolished specimens., Conclusion: The thickness and polishing of the restorations were both significant influential factors in light transmission., Clinical Significance: The range of light transmission percentage through the novel chairside CAD/CAM lithium disilicate blocks was 7.7-16.1%, suggesting that light attenuation through the material may influence the polymerization reaction of resin luting cement in the bonding process.

Objective: Optimal tooth reduction is a key requirement for aesthetics, function, and the longevity of fixed restorations. Research has demonstrated that controlled and conservative tooth preparation is crucial for the long-term success of adhesive restorations. Different techniques of fabricating reduction guides have been previously reported in literature. The present technical note describes the fabrication technique and clinical application of a customized metal preparation reduction guide., Material and Method: Patient presented with tilted maxillary left central incisor. The flared-out part of the tooth was modified prior to veneer restoration preparation. Resin pattern reduction guide was fabricated on the diagnostic cast with a window on the tilted mesial portion of the tooth. After intraoral evaluation, resin pattern guide was casted. Metal reduction guide was place intraorally and reduction was provided on the exposed surface of the tooth. After the removal of the tilted portion, a harmonious arch form allowed the clinician to provide adequate evaluation and preparation for veneer restorations., Results: The device demonstrated good practical value, allowing for selective and controlled reduction of tooth structure, and definitive protection of adjacent tooth surfaces from iatrogenic damage. The clinical outcome successfully addressed the patient's restorative and aesthetic needs, and the veneer was stable 2 years postoperatively., Conclusion: Use of a metal guide assists clinicians to provide a more predictable reduction of a desired tooth surface, while decreasing the risk of compromising the other/adjacent tooth surfaces., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 King Saud University.)

Background and Objective: Cortisol levels remain uninvestigated in peri-implant sulcular fluid (PISF) of patients with and without peri-implantitis. The present investigation investigated levels of cortisol in PISF among controls (individuals without peri-implantitis) and patients with peri-implantitis., Methods: The patient population comprised of participants with and without peri-implantitis (groups 1 and 2, respectively). Demographic information and data related to implant characteristics was recorded. Peri-implant radiographic (crestal bone loss [CBL]) and clinical (modified plaque and bleeding on probing indices [PI and BOP], and probing depth [PD]) and parameters were assessed. In all patients, levels of cortisol were measured in the PISF, which was collected using standard methods. Data normality and group comparisons were assessed, and multiple logistic regression was performed. Probability values less than 0.01 were nominated as being significant., Results: Eighty-eight individuals (44 and 44 in groups 1 and 2, correspondingly) were included. In group 1, 24 and 20 participants were males and females, and there were 22 and 22 males and females in group 2. Mean ages were analogous in both groups. Peri-implant BOP (p < .001); CBL (p < .001); PI (p < .001); and PD (p < .001) were higher among patients in group 1 compared with group 2. The volume of PISF (p < .001) collected and its concentrations of cortisol (p < .001) were significantly higher among patients in group 1 compared with group 2. Regression analysis showed that CBL and PD directly correlated with increased PISF levels of cortisol among participants with peri-implantitis., Conclusion: Within the limits of the present study, it remains debatable whether or not PISF cortisol levels vary among patients with and without peri-implantitis. Further studies are needed to evaluate the role of PISF levels of cortisol in the diagnosis of peri-implantitis., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: To evaluate the effect of time and hydration (ageing) on flexural strength of yttrium-stabilized zirconia polycrystals (Y-TZP) zirconia fabricated from three different materials., Methods: This in-vitro study was performed from June to September 2019. Y-TZP bars, measuring 2 x 3 x 20 mm were prepared and sintered from three different materials, Group-1: LAVA™ Zirconia (3M ESPE, US) (control) Group-2: Vita In-Ceram YZ (VITA, Germany) and Group-3: Aadva™ Zirconia (Zr) (GC Advanced technologies Inc.). 30 zirconia bars per group were prepared using sectioning of blocks with isomet saw. Followed by sintering in furnaces for recommended temperature cycles. One side of bars were polished and beveled for flexural testing. Groups of specimens were divided into subgroups of 3 (n=10) based on the ageing (distilled water in the incubator at 37ºC) durations (48 Hrs and two and half years). Ten specimens in each material groups were not aged (controls). Samples were exposed to a static force in a three-point bend test using a universal instron-testing machine until fracture. Scanning electron microscopic assessment was performed for fractured specimens for ageing. Data was analyzed using ANOVA and Tukey post hoc test., Results: The mean flexural strength at baseline for Group-1: LAVA™ Zirconia, group (632.7 ± 136.5 MPa) 2: Vita In-Ceram YZ (1036.3 ± 229.6 MPa), and Group-3: Aadva™ Zirconia (1171.3 ± 266.3 MPa) were significantly different. Group-2 and Group-3 specimens showed higher strength compared to Group-1 specimens, irrespective of the ageing duration (p<0.05). Analysis of pooled data for flexural strength for materials by aging period (baseline, after 48 hours and after 2 and ½ years) showed that there was significant reduction of strength with increasing duration (p<0.05)., Conclusions: Y-TZP showed variations in flexural strength depending on the material type. Ageing duration exhibited significant influence on the flexural strength of Y-TZP when comparing no ageing to two and half years. Vita In-Ceram YZ and Aadva Zirconia (Zr) showed higher and clinically acceptable flexural strength outcomes., Competing Interests: Conflicting interests: The authors declare that they have no conflict of interest., (Copyright: © Pakistan Journal of Medical Sciences.)

Objective: A comparison of the initial stability of narrow- and standard-diameter implants (SDIs) placed in Type-I and Type-IV bone-blocks is not yet reported. The aim was to evaluate in-vitro the influence of implant diameter on the initial stability of narrow- and standard-diameter implants (SDIs) placed in simulated Type-I and Type-IV bone-blocks., Methods: The present experimental in-vitro study was performed between July and September 2020 at the Specialist Dental Practice, Riyadh, Saudi Arabia. Narrow- and standard-diameter implants were placed 3-mm apart in simulated soft (Type-IV) and dense (Type-I) bone blocks by a trained and calibrated investigator. In groups A (Type-IV bone blocks) and B (Type-I bone blocks), implants were inserted using an insertion-torque and drilling-speed of 15-30 Ncm and 1000-1500 rpm, respectively with the implant collar at the crest of simulated bone blocks. In all samples, initial-stability was recorded using resonance frequency analysis (RFA). Sample-size estimation was done and group-comparisons were carried out. A P-value of 0.01 or less reflected statistical significance., Results: In Groups-A and -B, 44 (22 NDIs and 22 SDIs) and 44 (22 NDIs and 22 SDIs) were placed. In group-A, the mean RFA values for NDIs and SDIs were 68.5 ± 3.5 and 69.1 ± 2.4, respectively. In Group-B, the mean RFA values for NDIs and SDIs were 78.06 ± 9.6 and 75.3 ± 5.2. RFA values among NDIs and SDIs in groups A and B were similar., Conclusion: The NDIs and SDIs show comparable initial-stability when positioned in simulated Type-I and Type-IV bone blocks., (Copyright: © Pakistan Journal of Medical Sciences.)

Background: Clinicoradiographic status of narrow-diameter implants (NDIs) among patients with prediabetes and type 2 diabetes mellitus (DM) is scarce. The aim was to address the clinicoradiographic status of NDIs placed prediabetic, type 2 diabetic, and non-diabetic individuals. In this retrospective cohort study, patients having undergone oral rehabilitation with NDI were included. The participants were divided into the following: (a) patients with prediabetes; (b) patients with poorly controlled type 2 DM; (c) patients with well-controlled type 2 DM; and (d) normoglycemic individuals. Demographic data was collected. In all groups, peri-implant plaque index (PI), gingival index (GI), probing depth (PD), and mesiodistal CBL were measured in all groups. Information related to implant dimensions, surface characteristics, insertion torque, implant geometry, duration of NDI in function, and jaw location of NDI was also recorded. Data normality was assessed and group comparisons were performed. A probability value under 0.01 was considered statistically significant., Results: Eighty-three patients (20 patients had prediabetes, 22 with poorly controlled type 2 DM, 20 with well-controlled type 2 DM, and 20 self-reported non-diabetic individuals) were included. The mean HbA1c levels were significantly higher among patients with prediabetes (P < 0.01) and poorly controlled type 2 DM (P < 0.01) than patients with well-controlled type 2 DM and non-diabetic controls. Peri-implant PI, GI, PD, and mesiodistal CBL levels were significantly higher among patients with pre-diabetes (P < 0.01) and poorly controlled type 2 DM (P < 0.01) than patients with well-controlled type 2 DM and non-diabetic controls. Peri-implant PI, GI, PD, and mesiodistal CBL levels were significantly higher among patients with poorly controlled type 2 DM (P < 0.01) than patients with prediabetes., Conclusion: Chronic hyperglycemia increases the risk of peri-implant diseases around NDIs.

Background: Obesity appears to govern peri-implant hard and soft tissue health. We hypothesized that adjunctive photodynamic therapy (aPDT), improves clinical peri-implant perimeters and alleviates peri-implant crevicular fluid (PICF) levels of tumour necrosis factor (TNF)-α, interleukin (IL)-6 and high sensitivity C-reactive protein (hsCRP) in obese with moderate peri-implantitis. The current clinic-laboratory study aimed to determine whether obesity influences the outcomes of aPDT in patients with moderate peri-implantitis., Methods: A total of 49 patients (24 obese and 25 non-obese) with moderate periodontitis receiving aPDT were included. Clinical characteristics including peri-implant probing depth (PIPD), peri-implant bleeding on probing (PIBOP), and peri-implant plaque index (PIPI) were measured. PICF levels of TNF-a, IL-6 and hsCRP were assessed using enzyme-linked immunosorbent assay (ELISA). Both clinical and cytokine assessments were performed at baseline, three months and six months, respectively. Intra-group comparisons of changes in clinical parameters pre and post PDT was performed using Friedman test. Comparison of changes of TNF-a, IL-6 and hsCRP levels within group was performed using Kruskal-Wallis test., Results: When compared with the baseline, a considerable reduction in PIPI, PIBOP and PIPD was observed in obese as well as non-obese patients at three- and six-months follow-up. At three months follow-up, a statistically significant difference was observed in PIPI (p < 0.05), PIBOP (p < 0.05) and PIPD (p < 0.05) among obese and non-obese individuals. Additionally, when compared with the baseline, a statistically significant difference was noticed in PICF volume (p < 0.05) and levels of TNF-α (p < 0.05) and IL-6 (p < 0.05) in non-obese as well as obese at three- and six-months follow-up., Conclusion: With the application of aPDT, considerable improvement was observed in peri-implant inflammatory parameters among obese and non-obese patients with moderate peri-implantitis. Obesity did not appear to influence aPDT outcome in patients with moderate peri-implantitis., (Copyright © 2020. Published by Elsevier B.V.)

Background: Although studies have been done that evaluated the effect of photodynamic therapy (PDT) in cigarette smokers and vapers, however, literature on the impact of these types of smoking on peri-implant parameters lack. The present clinical trial assessed the effectiveness of PDT as an adjunctive therapeutic modality in the treatment of peri-implant mucositis (p-iM) in individuals vaping e-cigs and cigarette smokers., Methods: Individuals with p-iM were divided into three groups. (a) Group 1: Cigarette smokers with p-iM (b) Group 2: Vapers (e-cigarette smokers) with p-iM, (c) Group 3: Non-smokers with p-iM. Plaque index (PI), bleeding on probing (BOP) and probing depth (PD) were calculated. Pro-inflammatory biomarkers including matrix metalloproteinase (MMP)-8 and tumor necrosis factor-alpha (TNF-α) were quantified using enzyme linked immunosorbent assay. All assessments were performed at baseline (before treatment) and 12 weeks post treatment. Full mouth disinfection (FMD) was done with the ultrasonic scaler and copious irrigation. The photodynamic therapy (PDT) was done with a diode laser (wavelength: 670 nm, power: 150 mW, density: 1.1 W/cm2). Methylene blue photosensitizer (0.005% concentration) was incorporated inside the periimplant pockets (10 seconds at a depth of 3 mm), and the pockets were irradiated a flexible tip for one minute on the buccal and lingual surfaces. The session of PDT was performed only once at baseline., Results: Twenty-five cigarette-smokers (Group 1), 21 electronic cigarette smokers (Group 2) and 25 never-smokers (Group 3) participated in the study. The mean age of the selected participants in groups 1, 2 and 3 was 29.5, 27.8, and 30.2 years, respectively. Statistically significant reduction in PI and PD parameters was observed on baseline and at 12 weeks in all groups. BOP significantly increased in group 1 and 2 at 12 weeks. A statistically significant reduction from baseline to 12 weeks was reported in the biomarker levels for all the study groups., Conclusion: PDT with adjunctive mechanical debridement reduced the plaque index and probing depth, while increased bleeding on probing, in addition to reducing pro-inflammatory biomarkers in tobacco smokers., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: What impact does tobacco smoking have on photodynamic therapy (PDT) outcome is still unknown. The aim of the present clinical trial was to evaluate the clinical, radiographic, and biological bone markers after provision of PDT in cigarette, e-cigarette, and never-smokers with peri-implantitis (PI) at 6 months post treatment., Materials and Methods: Twenty-five healthy patients with PI were divided into three groups: Group I: cigarette smokers; Group II: e-cigarettes users; Group III: never-smokers. Full-mouth mechanical debridement with adjunctive methylene blue-mediated PDT was performed. Clinical recordings included peri-implant plaque index (Pi), bleeding on probing (BOP) and probing depth (PD). Peri-implant sulcular fluid was collected for the assessment of biological bone biomarkers including receptor activator of nuclear factor-ligand (RANK-L) and osteoprotegrin (OPG). All assessments were performed at baseline, 3 months and 6 months. P-value of <0.05 was considered significant., Results: BOP in Group II and III significantly reduced at 3 months (p < 0.05). Group I showed significant reduction only at 6 months (p < 0.05). Mean PD showed no statistically significant difference between the groups at any time-point. Inter-group comparison showed Group III demonstrating statistically significantly reduced mean RANK-L levels at both 3 and 6 months (p < 0.05). A slight increase in the OPG levels were observed at 3 months and followed by a slight decrease at 6 months for all the study groups when compared with baseline values, however, these values did not show statistical significance (p > 0.05)., Conclusion: Adjunctive PDT helped in reducing the clinical peri-implant inflammation. However, no significant change was observed for biological bone biomarkers among tobacco smokers., (Copyright © 2020 Elsevier B.V. All rights reserved.)