Salivary Metalloproteinase-8 and Metalloproteinase-9 Evaluation in Patients Undergoing Fixed Orthodontic Treatment before and after Periodontal Therapy

Integrating network pharmacology and experimental evaluation to explore the complementary therapeutic effect and mechanism of melatonin in periodontitis

Objective

To explore the potential targets for melatonin in the treatment of periodontitis through network pharmacologic analysis and experimental validation via in vivo animal models and in vitro cellular experiments.

Materials and methods

In this study, we first screened melatonin targets from Pharm Mapper for putative targets, Drug Bank, and TCMSP databases for known targets. Then, disease database was searched and screened for differential expressed genes associated with periodontitis. The intersection of disease and melatonin-related genes yielded potential target genes of melatonin treatment for periodontitis. These target genes were further investigated by protein-protein interaction network and GO/KEGG enrichment analysis. In addition, the interactions between melatonin and key target genes were interrogated by molecular docking simulations. Then, we performed animal studies to validate the therapeutic effect of melatonin by injecting melatonin into the peritoneal cavity of ligation-induced periodontitis (LIP) mice. The effects of melatonin on the predicted target proteins were also analyzed using Western blot and immunofluorescence techniques. Finally, we constructed an in vitro cellular model and validated the direct effect of melatonin on the predicted targets by using qPCR.

Results

We identified 8 potential target genes by network pharmacology analysis. Enrichment analysis suggests that melatonin may treat periodontitis by inhibiting the expression of three potential targets (MPO, MMP8, and MMP9). Molecular docking results showed that melatonin could effectively bind to MMP8 and MMP9. Subsequently, melatonin was further validated in a mouse LIP model to inhibit the expression of MPO, MMP8, and MMP9 in the periodontal tissue. Finally, we verified the direct effect of melatonin on the mRNA expression of MPO, MMP8, and MMP9 in an in vitro cellular model.

Conclusions

Through a combination of network pharmacology and experimental validation, this study provides a more comprehensive understanding of the mechanism of melatonin to treat periodontitis. Our study suggests that MPO, MMP8, and MMP9 as key target genes of melatonin to treat periodontitis. These findings present a more comprehensive basis for further investigation into the mechanisms of pharmacological treatment of periodontitis by melatonin.

Clinical parameters and inflammatory biomarkers among patients with multibracket appliances: a prospective clinical trial

BACKGROUND

Aim of the presented study was to investigate changes in clinical parameters and active matrix metalloproteinase-8 (aMMP-8) levels in gingival crevicular fluid of patients before and during treatment with multibrackets appliances.

METHODS

Fifty-five adolescents scheduled for the treatment were included. Clinical parameters and subgingival samples were obtained at six time points: 1 week before appliance insertion (T0), 3 (T1), 6 (T2) weeks, 3 (T3), 6 (T4) months, and 1 year (T5) after that. Gingival index and plaque index were assessed to evaluated changes on the clinical status. Subgingival samples were collected to analyze changes in aMMP-8.

RESULTS

Scores for gingival and plaque index increased after bracket insertion. The gingival index increased from T2 (p < 0.05) until T5 (p < 0.0001). Plaque index also increased, reaching its maximum peak at T3 (p < 0.05). Moreover, an increase of aMMP-8 levels (p < 0.05) was noted. There was no significant between upper and lower jaws.

CONCLUSIONS

Treatment with multibracket appliances in adolescents favors dental plaque accumulation and may transitionally increase gingival and plaque index and aMMP-8 levels leading to gingival inflammation, even 1 year after therapy began.

TRIAL REGISTRATION

This study was approved by the Ethics Committee of the dental medical association Rheiland-Pfalz, Germany (process no. 837.340.12 (8441-F)), and followed the guidelines of Good Clinical Practices.

Accuracy of aMMP-8 point-of-care test in indicating periodontal treatment outcomes in stage III/IV periodontitis: A 24-week follow-up study

OBJECTIVE

To analyse the correspondence between aMMP-8 PoC test results and the clinical endpoints of non-surgical periodontal treatment in stage III/IV periodontitis.

BACKGROUND

The diagnostic success of the active-matrix metalloproteinase-8 (aMMP-8) point-of-care (PoC) test has been demonstrated in various studies, but the evidence of its accuracy following periodontal treatment is limited.

MATERIALS AND METHODS

Altogether 42 stage III/IV grade C periodontitis patients were included in this prospective diagnostic study. Clinical periodontal indices were recorded, aMMP-8 PoC test was applied and mouthrinse was collected before and at 6, 12 and 24 weeks after non-surgical periodontal treatment. Quantitative aMMP-8 levels were determined with immunofluorometric assay (IFMA) for the verification of the PoC test results. The accuracy of the aMMP-8 PoC test was assessed using previously established clinical endpoints as references.

RESULTS

Sensitivity and specificity of aMMP-8 PoC test to indicate clinical endpoints were ranged as follows: Sensitivity 71.4% at baseline, 39.3%-42.4% at week 6, 28.6%-32.4% at week 12 and 35.3%-42.9% at week 24; specificity 64.3%-80% at week 6, 40%-57.1% at week 12 and 56%-64.3% at week 24.

CONCLUSIONS

The accuracy of aMMP-8 PoC test in identifying clinical endpoints after non-surgical periodontal treatment is reduced in relation to baseline. Individual healing patterns of each diseased pocket eventually limit the accuracy of the dichotomous aMMP-8 oral rinse test during the post-treatment period.

The Influence of Chlorhexidine Gluconate Dentine Pre-Treatment on Adhesive Interface and Marginal Sealing

Background and Objectives: The aim of this in vitro study was to evaluate the combined effect of a 2% chlorhexidine aqueous solution and a universal adhesive system applied in self-etch and etch-and-rinse strategies on the composite resin-dentin interface. Materials and Methods: Class V cavities were prepared on the facial and lingual surfaces of forty caries-free molars extracted for orthodontic reasons. The samples were randomly divided into two groups corresponding to the used etching protocol: I-etch-and-rinse; II-self-etch. In each tooth, one cavity was assigned for the control subgroups -IA (n = 20) and IIA (n = 20)-adhesive only, and the opposite cavity was pretreated with a 2% chlorhexidine solution-Gluco CHeX Cerkamed-subgroups IB (n = 20) and IIB (n = 20). Both sets of groups were restored using a universal adhesive system (Single Bond Universal Adhesive, 3M-ESPE) and a bulk-fill composite resin (Filtek One Bulk Fill Restorative, 3M-ESPE). The roots and the pulp tissue were then removed, and a needle connected to a perfusor with 100 mL saline solution was used for pulp pressure simulation with a hydrostatic pressure of 20 cm H₂O. Cariogenic attack was simulated using a demineralizing solution for 3 days at a constant temperature of 25 °C. The teeth were then sectioned in a facial-lingual direction and the microleakages at the occlusal and cervical margins were registered and scored using an optical Carl-Zeiss AXIO Imager A1m microscope (Carl-Zeiss). The composite resin-dentin interface was analyzed using a SEM Vega Tescan LMH II. Statistical analysis was performed using the Kruskal-Wallis test with a significance level of p < 0.05. Results: Microleakage evaluation showed no significant differences among the study groups (p > 0.05). In subgroup IA, significant differences were recorded between occlusal and cervical margins (p < 0.05). Conclusions: Application of chlorhexidine on tooth substrate before using a universal bonding system in total etch or self-etch mode has no influence on the adhesive interface in the condition of cariogenic attack. The thickness of the adhesive resin layer seems to be less uniform when using chlorhexidine, but the morphological differences at the adhesive interface have no influence on the sealing capacity of the universal bonding system, regardless of the etching strategy.

Salivary peptidome analysis and protease prediction during orthodontic treatment with fixed appliances

Orthodontic tooth movement (OTM) occurs through proteolytic remodelling within the periodontium following the application of external force to the tooth. This study describes the first characterization of the salivary peptidome and protease profile during the alignment stage of fixed appliance orthodontic treatment. Unstimulated whole mouth saliva from 16 orthodontic patients (10 males, 6 females, mean (SD) age 15.2 (1.6) years) was collected prior to fixed appliance placement (T1), 1-h (T2), 1-week (T3) following fixed appliance placement and on completion of mandibular arch alignment (T4). Salivary peptides were extracted using filtration followed by mass spectrometry to identify amino acid sequences. Protease prediction was carried out in silico using Proteasix and validated with gelatin zymography and enzyme-linked immunosorbent assay. A total of 2852 naturally-occurring peptides were detected, originating from 436 different proteins. Both collagen and statherin-derived peptide levels were increased at T2. Proteasix predicted 73 proteases potentially involved in generating these peptides, including metalloproteinases, calpains and cathepsins. Changes in predicted activity of proteases over time were also observed, with most metalloproteinases showing increased predicted activity at T2-T3. Increased gelatinolytic activity and MMP8/MMP9 levels were detected at T3. Collectively, multiple protein targets and changes in protease-predicted activity during OTM have been identified.

Effects of Laser Therapy on Periodontal Status in Adult Patients Undergoing Orthodontic Treatment

Orthodontic treatment with fixed devices should only be indicated in case of a stable, non-active periodontal disease status. Throughout orthodontic treatment, a careful assessment of the periodontal status is advised. Due to its anti-inflammatory and antimicrobial effects, laser therapy is frequently used as an adjunct to classic periodontal therapy. The aim of this study was to evaluate the advantages and limitations of the use of laser therapy on periodontal status during orthodontic treatment. Throughout the 9 months during which this placebo-controlled, single-blind clinical trial was conducted, 32 patients were included in the study, divided into two groups: microscope “+” (patients who observed the bacteria within the dental plaque-sample examination on the screen of a dark-field microscope in real time) and microscope “−” (patients who did not see the oral pathogens using a dark-field microscope). For all patients, using the split-mouth study design, laser therapy was applied to one hemiarch (HL), whereas the other hemiarch received treatment without active light (HC). After one month, by analyzing the main indicators of periodontal health status, we found that the plaque index (PI) and bleeding on probing (BOP) values were significantly decreased after receiving treatment (for PI: HL-p = 0.0005, HC-p = 0.0297; for BOP: HL-p = 0.0121, HC-p = 0.0236), whereas the probing-depth (PD) values remained almost the same as before treatment (HL-p = 1.5143; HC-p = 1.4762). Conclusions: The use of the dark-field microscope proved to be beneficial in sensitizing patients to the presence of bacteria in the oral cavity and motivated them to strictly follow the rules of oral hygiene. Laser treatment can be a valuable aid in periodontal therapy, but only in adjunction with mechanical therapy.

Long-Term CBCT Evaluation of Mandibular Third Molar Changes after Distalization in Adolescents

Introduction: This study aimed to evaluate mandibular molar changes after distalization using Class III elastics and modified C-palatal plates (MCPPs) in the maxilla and to use CBCT to specifically analyze the third-molar position after long-term retention in adolescents. Methods: The sample consisted of 65 mandibular third molars from 35 subjects, divided into two groups. Twenty-six of the third molars were from fourteen adolescent patients with Class I bimaxillary protrusion (mean age, 12.8 years) who had undergone bilateral maxillary distalization using an MCPP and mandibular distalization with Class III elastics with non-extraction treatment. For the control group, 39 third molars from 21 Class I normal-occlusion subjects were used. In the treated group, CBCT images were taken before distalization (T1), after molar distalization (T2), and at a long-term observation point (6.1 ± 2.7 years) (T3). Repeated measures ANOVA and a post hoc test with Bonferroni correction were used to analyze significant differences in the positions at the three points in time. Results: There were 2.3 and 1.7 mm of distal movement at the crown of the mandibular first and second molars, with distal tipping of 5.2° and 5.3°, respectively, and 3.0° of distal tipping of the third molars. Comparing the treated group with the control group at T3, there was a significant change in the angulation of the third molars (p < 0.001). In the long-term, the third molars from the treated group showed a downward and buccal position after distalization. Conclusions: In the long term, the developing mandibular third molar buds had downward and buccal positional changes after total arch distalization. These findings suggest the need for clinicians to consider the possibility of the impaction of developing third molars after mandibular total arch distalization in adolescents.

Patient-Reported Outcome Measures on Oral Hygiene, Periodontal Health, and Treatment Satisfaction of Orthodontic Retention Patients up to Ten Years after Treatment-A Cross-Sectional Study

Background: This cross-sectional study evaluated patient-reported outcome measures (PROMs) on (1) oral hygiene, (2) periodontal health, (3) retainer failure, (4) orthodontic treatment satisfaction, and (5) outcome satisfaction in orthodontic retention patients. The purpose of the study was to evaluate whether orthodontic retention treatment is associated with patient-reported outcome measures on oral hygiene, periodontal health, and treatment satisfaction. Methods: A ten-item questionnaire on the five PROMs was conducted among 211 consecutive retention patients up to ten years following orthodontic treatment. Linear regression models were computed to detect possible associations between the PROMs and retention treatment or patient characteristics. Results: The presence of a fixed lingual retainer was not associated with the reduced ability to perform oral hygiene, self-perceived periodontal health, or orthodontic outcome satisfaction. Older patients were more content with the orthodontic treatment result (p < 0.05). Patients with fixed lingual retainers in the mandible were less satisfied with the course of orthodontic treatment (p < 0.05). Smokers more often reported gingival bleeding (p < 0.05). Females reported increased gingival recessions (p < 0.05) and perceived their teeth as longer than before treatment (p < 0.05). Longer orthodontic treatment duration corresponded to retainer failure (p < 0.05). Conclusions: In general, long-term orthodontic retention patients were satisfied with orthodontic treatment. These patients reported the satisfactory ability to perform adequate oral hygiene and periodontal health, and they communicated a high degree of treatment and outcome contentment. However, patients with a retainer in the mandible were less satisfied with orthodontic treatment.

The Effects of Periodontal Laser Therapy on Pain in Adult Patients with Orthodontic Treatment: A Randomized Clinical Trial

(1) Background: Pain is the most common complaint of patients with fixed orthodontic treatment, especially when applying and activating the orthodontic device. The effectiveness of low-level laser therapy (LLLT) in reducing pain caused by the orthodontic treatment has been frequently studied over the last few years. In this study, we aim to evaluate the influence of laser therapy on pain caused by orthodontic forces acting on periodontal tissues during fixed orthodontic treatment. (2) Methods: A total of 36 patients who met the inclusion criteria were submitted to laser therapy after beginning a fixed orthodontic treatment. For each patient, one half-arch was treated with laser (HL), the opposite one being the control half-arch (HC). The evaluation of pain was conducted by asking the patients to rate their pain on a VAS scale from 0 to 10. (3) Results: Analyzing the VAS score values reported after applying the orthodontic device, we noticed that the pain increased in the first few hours, it was the highest 24 h after application, and it decreased towards the 7th day. The pain reported by most patients was significantly reduced in the HL compared to the HC, in all three moments that were evaluated (p < 0.0001). (4) Conclusions: Repeated LLLT in patients with orthodontic treatment leads to a significant decrease in pain levels, as the comparison between the laser half-arch and the control half-arch showed.

Ability of matrix metalloproteinase-8 biosensor, IFMA, and ELISA immunoassays to differentiate between periodontal health, gingivitis, and periodontitis

Objective

The aim of this study was to determine the diagnostic utility of an MMP‐8 biosensor assay in differentiating periodontal health from gingivitis and periodontitis and compare it with an established time‐resolved immunofluorescence assay (IFMA) and enzyme‐linked immunosorbent assay (ELISA).

Background

Currently available antibody‐based assays display a wide variability in their ability to accurately measure matrix metalloproteinase‐8 (MMP‐8) levels in saliva.

Methods

Salivary MMP‐8 levels were analyzed in 189 systemically healthy participants using an antibody‐based biosensor prototype that operates using a surface acoustic wave technology and compared with IFMA and ELISA antibody assays. Participants were categorized into 3 groups: periodontal health (59), gingivitis (63), and periodontitis (67). A sub‐population of participants (n = 20) with periodontitis received periodontal treatment and were monitored for 6 months.

Results

All the assays demonstrated significantly higher salivary MMP‐8 concentrations in participants with periodontitis versus gingivitis, periodontitis versus health, and gingivitis versus health (all p < .05). The biosensor data demonstrated significant correlations with IFMA (r = .354, p < .001) and ELISA (r = .681, p < .001). Significant reductions in salivary MMP‐8 concentrations were detected by the biosensor (p = .030) and IFMA (p = .002) in participants with periodontitis 6 months after non‐surgical periodontal treatment. IFMA had the best sensitivity (89.2%) for detecting periodontitis and gingivitis versus health and 96.6% for detecting periodontitis versus health and gingivitis. The biosensor had an AUC value of 0.81 and diagnostic accuracy of 74.2% for differentiating periodontitis and gingivitis from health; an AUC value of 0.86 and diagnostic accuracy of 82.8% for periodontitis versus health and gingivitis.

Conclusions

The biosensor, IFMA, and ELISA assays differentiated between periodontal health, gingivitis, and periodontitis based on salivary MMP‐8 levels. Only the biosensor and, particularly, IFMA identified an effect of periodontal treatment in the participants with periodontitis. Our findings support the potential utility of salivary oral fluid aMMP‐8‐based point‐of‐care technology in the future of periodontal diagnostics.

Study on the Mechanism of Capillary Leakage Caused by Hypoxia-Inducible Factor-1α through Inducing High Expression of Matrix Metalloproteinase-9

Purposes

This study mainly explored the mechanism of capillary leakage caused by hypoxia-inducible factor-1α through inducing high expression of matrix metalloproteinase-9. Method. We established a monolayer endothelial cell model by culturing human umbilical vein endothelial cells (HUVEC) in vitro, used tumor necrosis factor (TNFα) and HIF-1α inhibitor 2-methoxyestradiol (2ME2) to act on HUVEC, and at the same time constructed siRNA-transfected HUVEC to interfere with the expression of HIF-1α. The permeability of monolayer endothelial cells was measured by transwell chamber method, the concentration of MMP-9 in the supernatant was measured by ELISA method, the expression of key molecules related to permeability (HIF- 1α, MMP-9, claudin-5, and ZO-1) was measured by RT-PCR and Western blot method, and the localization and expression of claudin-5 and ZO-1 were measured by immunofluorescence method. We searched for 7 HIF-1α hypoxia response elements within 4000 bp before the transcription start site in the MMP-9 promoter region, constructed the MMP-9 promoter-luciferase reporter gene recombinant plasmid, transfected and stimulated HUVEC with TNFα, and detected the effect of 7 hypoxia response element plasmids on the transcription activity of MMP-9 promoter.

Results

Under the action of TNFα, the permeability of monolayer endothelial cells increased, and the concentration of MMP-9 in the cell supernatant increased. 2ME2 and HIF-1α-siRNA transfection can improve the above situation (P < 0.05). 2ME2 and HIF-1α-siRNA transfection can inhibit the high expression of HIF-1α and MMP-9 caused by TNFα, thereby increasing the expression of claudin-5 and ZO-1 (P < 0.05). 2ME2 and HIF-1α-siRNA transfection can reduce the inhibition of TNFα on the expression of cell membrane protein claudin-5 and tight junction protein ZO-1. Element 1, element 5, and element 7 are the sites where HIF-1α interacts with MMP-9 at the transcription level.

Conclusion

This study shows that HIF-1α can increase the permeability of monolayer epithelial cells by inducing the high expression of MMP-9, leading to capillary leakage. Its target is at the -3798 bp, -1878 bp, and -1489 bp points of the transcription initiation site in the MMP-9 promoter region.

Using FEM to Assess the Effect of Orthodontic Forces on Affected Periodontium

Orthodontic treatment in patients with no periodontal tissue breakdown vs. horizontal bone loss should be approached with caution even though it can bring significant benefits in terms of periodontal recovery and long-term success. We used the finite element method (FEM) to simulate various clinical scenarios regarding the periodontal involvement: healthy with no horizontal bone loss, moderate periodontal damage (33%) and severe horizontal bone loss (66%). Afterwards, forces of different magnitudes (0.25 N, 1 N, 3 N, and 5 N) were applied in order to observe the behavioral patterns. Through mathematical modeling, we recorded the maximum equivalent stresses (σ ech), the stresses on the direction of force application (σ c) and the displacements produced (f) in the whole tooth–periodontal ligament–alveolar bone complex with various degrees of periodontal damage. The magnitude of lingualization forces in the lower anterior teeth influences primarily the values of equivalent tension, then those of the tensions in the direction in which the force is applied, and lastly those of the displacement of the lower central incisor. However, in the case of the lower lateral incisor, it influences primarily the values of the tensions in the direction in which the force is applied, then those of equivalent tensions, and lastly those of displacement. Anatomical particularities should also be considered since they may contribute to increased periodontal risk in case of lingualization of the LLI compared to that of the LCI, with a potential emergence of the “wedge effect”. To minimize periodontal hazards, the orthodontic force applied on anterior teeth with affected periodontium should not exceed 1 N.