Retro MTA and tricalcium phosphate/retro MTA for guided tissue regeneration of periodontal dehiscence defects in a dog model: a pilot study

Objectives: Retro MTA is a fast setting Calcium silicate cement used in endodontic regeneration procedures in recent years. Beta-tricalcium phosphate (β-TCP) is another common biomaterial used for bone augmentation procedures. The present pilot study was undertaken to evaluate and compare the efficacy of Retro MTA and a mixture of Retro MTA / β-TCP for periodontal tissue regeneration. Materials and methods: In 4 beagle dogs, periodontal dehiscence type defects were created. In each side, one dehiscence defect was left empty as a control site and three treatment modalities were randomly applied for the others: Retro MTA covered with a collagen membrane, Retro MTA + β-TCP covered with a membrane and covering the defect with a membrane without any bone augmentation. After 8 weeks Animals were sacrificed and Histomorphometric and histologic analysis were conducted. Results: Histologic analysis showed more cementum formation for both Retro MTA+ β-TCP (3.74 ± 0.34 mm) and Retro MTA group (3.24 ± 0.56 mm) compared to control group 1 (1. 15 ± 0.45 mm) and control group 2 (0.78 ± 0.65 mm). Formation of newly formed bone and cementum in the experimental groups were significantly higher as compared to the control groups (P < 0.0001). Conclusions: Retro MTA or Retro MTA+ β-TCP covered with a collagen membrane resulted in regeneration of periodontal tissues. However, Retro MTA+ β-TCP showed tendency towards better results than the use of Retro MTA alone. KEYWORDS: Bone regeneration; Calcium silicate cement; Guided tissue regeneration; MT

Evaluation of Covid-19 protection knowledge and practice of dentists in Isfahan in clinical environment

Background and Aims: The 2019 coronavirus pandemic has resulted in a lot of pressure on health systems around the world. The risk of transmission of infection in dentistry is significantly high. The aim of this study was to evaluate Covid-19 protection knowledge and practice of dentists in Isfahan in clinical environment. Materials and Methods: In this study which was performed in April 2021 by available sampling method, an online questionnaire was used as a data collection tool. Questions included demographic characteristics, knowledge of proper protective protocols, protection protocols taken against Covid-19, and the prevalence of Covid-19 infection. Descriptive and analytical analyzes were performed using SPSS26 software including frequency distribution tables, graphs, independent t-test, and Pearson and Spearman correlation coefficients. Results: 310 questionnaires were collected with complete answers. 87.4% of dentists had moderate and high knowledge of proper protective protocols against Covid-19. The mean knowledge score had no significant relationship with the demographic characteristics of age (P=0.59), gender (P=0.31 and r=0.05), work experience (P=0.16 and r=0.07) and degree (0.33=P). In the pandemic period, 87% of dentists treated dental emergencies and 40% delayed the dental treatment for patients with high risk of Covid-19. Dentists used personal protective equipment correctly. Among all the included dentists, 75% used high protection masks, 75% used face shields, 67% used hats, and 60% used sterile gowns in all of their treatment activities. The clinical environment was equipped well to prevent spreading of Covid-19. The results showed that 55.8% of the participants had one or more similar signs/symptoms of Covid-19 and 9% had a positive SARS-CoV-2 test during the last months. Conclusion: The majorities of dentists had enough knowledge of proper protective protocols against Covid-19 and efficiently used all protections while performing dental procedures

Comparison of bone regeneration using three demineralized freeze-dried bone allografts: A histological and histomorphometric study in rabbit calvaria

Background: It has been stated that the bone allografts from different tissue banks may lead to various amount of bone induction, so the aim of this study was to evaluate bone regeneration of three demineralized allografts both histologically and histomorphometrically in rabbits calvaria bone defects. Materials and Methods: In this double-blind randomized experimental animal study, 32 critical size defects (11-mm diameter) in the calvaria of 16 male New Zealand white rabbits were randomly filled with three demineralized freeze-dried bone allografts (DBM, CENOBONE, DEMBONE), while the nongrafted defect was regarded as control group. After 6 and 12 weeks of healing, the experimental animals were euthanized for specimen preparation. After histological evaluation, histomorphometric analysis was performed to quantify new bone formation and remained graft particles. The data were analyzed by one-way ANOVA with Tukey′s ad-hoc test and t-test. (P < 0.05 was considered to be statistically significant). Results: Mean percentage of bone formation increased between two healing time, but it was not statistically significant in all groups except DBM which the bone formation significantly decreased (P = 0.04). There were not statistically significant differences between three allografts in remained particles and bone formation in both healing times and they could not induce significantly more bone formation than control group. Conclusion: Both test and control groups resulted in successful new bone formation. No difference was noted in bone formation and remained particles between three commercial bone allografts. Further studies in this issue may be needed

Comparative Evaluation of IFNγ, IL4 and IL17 Cytokines in Healthy Gingiva and Moderate to Advanced Chronic Periodontitis

Background: Considering the role of T cells in the pathogenesis of periodontitis, the purpose of this study was to compare the amount of IFNγ, IL4 and IL17 in advanced periodontal lesions with healthy gum areas to determine each TH1, TH2 and TH17 cells activity in comparison with each other and finally, to compare the value and the role of humoral, cell mediate and autoimmune responses. Methods : In this descriptive analytical study, those with moderate to advanced periodontitis, having pocket with 4 to 7 mm in depth, were randomly selected. After preparing the healthy and affected sample tissues, the amount of the specific antibody in I IFNγ, IL4 and IL17 cytokines were measured using ELISA method and were compared between the two groups. The findings were analyzed using the software and descriptive statistical methods and Pearson correlation statistical analysis (α = 0.05). Results: This study was performed on 37 patients with moderate to severe periodontitis and 22 healthy individuals without any periodontal disease. IL4 and IFNγ levels in the patients with chronic periodontitis compared to those of healthy gingival samples showed a significant reduction (P > 0.05) whereas the amount of IL17 in tissue samples of chronic periodontitis compared to healthy gums had a significant increase (P < 0.05). Conclusion: It appears that in the periodontitis pathogenesis, as well as TH1 and TH2 responses, IL17 causes the host immunological response to the periodontal pathogenesis

Histological and histomorphometric analysis of animal experimental dehiscence defect treated with three bio absorbable GTR collagen membrane

Background: Guided tissue regeneration (GTR) allows mesenchymal cells to repopulate the defects. However, there is limited information regarding the efficacy of different membranes. The present study was designed to histologically and histomorphometrically compare three collagen membranes in regenerative treatment of dehiscence defects in dogs. Materials and Methods: This 8 weeks experimental animal study comprised 4 healthy dogs. 5 x 5 mm periodontal dehiscences were created in each side of the mandible (4 dehiscences in each side of dogs′ mandible). In each side, one dehiscence defect was left uncovered as a control site and three other sites were randomly covered with different collagen membranes (Biogide (BG), Biomend (BM), and Cytoplast (CYT)). Histomorphometric and histologic analysis were conducted at 4 and 8 weeks. Data were analyzed using ANOVA, Mann-Withney, Kruskal-Wallis and Fisher ′s exact tests (α = 0.05). Results: According to histomorphometric analysis there was a significant difference between treatment and control groups regarding the bone formation and the distance between the reference point and apical end of junctional epithelium (DJE) (P < 0.05). At 4 weeks, the maximum amount of bone thickness and height was observed in BG and CYT respectively, and this maximum rate was seen with the use of BG at 8 weeks. It was shown that DJE reached its highest rate in BM and CYT at 4 and 8 weeks, respectively. Organized PDL was formed in treatment groups. Conclusion: The membrane-treated groups had a statistically significant increase in bone formation and connective tissue attachment compared to control groups. However, there are some differences among experimental groups, which should be considered in GTR treatments

Serum, saliva, and GCF concentration of RANKL and osteoprotegerin in smokers versus nonsmokers with chronic periodontitis

Background: The role of host response in periodontitis pathogenesis is confirmed, and it is well established that immune response plays a major role in the alveolar bone destruction. In the investigation of these responses, the role of receptor activator of the nuclear factor-kB ligand (RANKL)-osteoprotegerin (OPG) system is the most promising. Smoking can affect the RANKL-OPG system in a manner that will further enhance bone loss in periodontitis. The aim of this study is to assess the serum, saliva, and gingival crevicular fluid (GCF) concentration of RANKL and OPG in smoker versus nonsmoker untreated chronic periodontitis (CP) patients. Materials and Methods: Thirty-nine subjects were included in the present cross-sectional study: 29 systemically healthy CP male patients (15 smokers, 14 nonsmokers) and 10 systemically and periodontally healthy nonsmoker male subjects. Serum, GCF, and whole saliva samples were obtained from the subjects. The enzyme-linked immunosorbent assay (ELISA) kits were used for assaying the concentrations of RANKL and OPG in the samples. The one-way analysis of variance (ANOVA) test and the least significant difference (LSD) post hoc test were utilized to compare differences between the groups. Results: RANKL and OPG concentrations in saliva, serum, and GCF did not show any significant difference among all groups (P > 0.05). Salivary RANKL/OPG ratios were significantly higher in the nonsmoker CP group than in the healthy control group (P > 0.05) but they were not statistically significant among smoker periodontitis patients. Conclusions: The salivary RANKL/OPG ratio was higher in nonsmokers with periodontitis in comparison with smoker periodontitis patients

Retro MTA and tricalcium phosphate/retro MTA for guided tissue regeneration of periodontal dehiscence defects in a dog model: a pilot study

Abstract Objectives Retro MTA is a fast setting Calcium silicate cement used in endodontic regeneration procedures in recent years. Beta-tricalcium phosphate (β-TCP) is another common biomaterial used for bone augmentation procedures. The present pilot study was undertaken to evaluate and compare the efficacy of Retro MTA and a mixture of Retro MTA / β-TCP for periodontal tissue regeneration. Materials and methods In 4 beagle dogs, periodontal dehiscence type defects were created. In each side, one dehiscence defect was left empty as a control site and three treatment modalities were randomly applied for the others: Retro MTA covered with a collagen membrane, Retro MTA + β-TCP covered with a membrane and covering the defect with a membrane without any bone augmentation. After 8 weeks Animals were sacrificed and Histomorphometric and histologic analysis were conducted. Results Histologic analysis showed more cementum formation for both Retro MTA+ β-TCP (3.74 ± 0.34 mm) and Retro MTA group (3.24 ± 0.56 mm) compared to control group 1 (1. 15 ± 0.45 mm) and control group 2 (0.78 ± 0.65 mm). Formation of newly formed bone and cementum in the experimental groups were significantly higher as compared to the control groups (P < 0.0001). Conclusions Retro MTA or Retro MTA+ β-TCP covered with a collagen membrane resulted in regeneration of periodontal tissues. However, Retro MTA+ β-TCP showed tendency towards better results than the use of Retro MTA alone

Isolation and characterization of human periodontal ligament stem cells under the terms of use in clinical application: A pilot study

Background: The aim of the present study is to determine the possibility of isolation and characterization of the human periodontal ligament stem cells (hPDLSCs) using limited harvested periodontal ligament (PDL) tissue of only one patient's wisdom teeth (2–4 teeth) under the more compatible terms of use in clinical application without using the fetal bovine serum (FBS). Materials and Methods: In this pilot study, hPDLSCs were isolated from the impacted third molar, and tissue was scraped from the roots of the impacted third molar of 10 volunteers to enzymatically digest using collagenase. The cells were sub-cultured. The samples of the first seven patients and half of the eighth patient's sample were cultured in alpha modified of Eagle's medium (α-MEM) (−FBS) medium and the other part of the eighth patient's sample was cultured with prior medium supplemented with +FBS 15% as a control of the cultivation protocol. While for the past two patients (9th and 10th the α-MEM medium was supplemented with L-Glutamine, anti/anti 2X, and 20% knock-out serum replacement (KSR). Two more nutritious supplements (N2 and B27) were added to the medium of the tenth sample. Flow-cytometric analysis for the mesenchymal stem cell surface markers CD105, CD45, CD90, and CD73 was performed. Subsequent polymerase chain reaction was undertaken on three samples cultured with two growth media. Results: Cultivation failed in some of the samples because of the lack of cell adhesion to the culturing dish bottom (floating cells), but it was successful for the 9th and 10th patients, which were cultured in the α-MEM serum supplemented with KSR 20%. Flow cytometry analysis was positive for CD105, CD90, and CD73 and negative for CD45. The PDL stem cells (PDLSCs) expressed CD105, CD45, and CD90 but were poor for CD73. Conclusion: According to the limited number of sample tests in this study, isolation and characterization of PDLSCs from collected PDL tissue of one patient's wisdom teeth (2–4) may be possible by the proper setup in synthetic FBS-free serum

A histomorphometric study of the effect of doxycycline and erythromycin on bone formation in dental alveolar socket of rat

Background: The aim of the present study was to evaluate whether subantimicrobial doses of doxycycline (DOX) and erythromycin (EM) used for the treatment of peri-implant osteolysis due to their anti-osteoclastogenesis can interfere with the osseous wound healing process in rat alveolar socket. Materials and Methods: Forty-five male Wistar rats had their first maxillary right molar extracted and were divided into three groups. DOX and EM at the doses of 5 mg/kg/day orally (p.o.) and 2 mg/kg/day intraperitoneally (i.p.) were administered respectively to two separate groups for 7 days after operation. In the control group the animals received normal saline (5 ml/kg). Five rats were sacrificed at 7, 14 and 21 days post-extraction in each study group. A histomorphometric analysis was used to evaluate new bone formation inside the alveolar socket. Significant level was set at 0.05. Results: The findings showed that the percentage of new bone formation (NBF) enhanced significantly on days 7 and 14. There was no significant difference in the NBF between DOX and EM groups. Conclusion: Short-term treatment with both DOX and EM enhanced new bone formation without any advances in favor of each drug

Comparison of the Efficacy and Side Effects of Chlorhexidine Mouthrinses with (Hexidine) and without (Epimax) Alcohol

Introduction: Chlorhexidine mouthrinses have widely been recognized for their contribution in maintaining plaque control. Most of them contain alcohol that makes them impractical for many patients. Alcohol-free mouthwashes may have fewer side effects but may be less efficient. The current study was aimed to compare the effectiveness and side effects of chlorhexidine mouthrinses with and without alcohol. Materials and Methods: In this double-blind clinical trial, 32 patients with moderate and severe gingivitis were recruited. For all patients, full prophylactic procedures, such as removal of plaque, calculus, and stains on the teeth, were performed. Each patient was asked to use 15 mL of the mouthrinse for 60 s twice daily. The patients were divided into two groups, one group used Hexidine (0.12% chlorhexidine and 10% ethanol) mouthwash and the other group used Epimax (0.12% chlorhexidine and 0.05% sodium fluoride) mouthwash. After 14 days, plaque (PI), gingival (GI), and stain indices were analyzed. The obtained data were analyzed by using SPSS 16 using covariance [Analysis of covariance (ANCOVA)] and t-test. Results: Both mouthwashes significantly reduced the mean scores of plaque (P < 0.0001) and gingival (P < 0.032) indices after 2 weeks; however, Hexidine mouthrinse was shown to be more effective. The extent of stain was the comparable in both groups. While Epimax mouthrinse caused severe stains on the teeth, Hexidine mouthrinse caused burning mouth. Conclusion: Although Epimax mouthwash did not show any side effects, it was less suitable and caused more dental stain. Ethanol-free Hexidine mouthwash seems to be more proper for gingivitis, but its side effects are required to be taken into consideration