Association between the severity of periodontitis, COVID-19, C-reactive protein and interleukin-6 levels in hospitalized patients: a case‒control study.

BACKGROUND: The COVID-19 pandemic is perhaps one of the most important events of the 21st century. Periodontitis is one of the most prevalent diseases of the oral cavity. Due to possible pathways of interaction between these two diseases, we investigated their association. METHODS: The study population consisted of hospitalized patients with established COVID-19 diagnoses. Patients with mild to moderate COVID-19 were considered controls, while cases had severe to critical COVID-19. Periodontal examination and serum and saliva sampling were performed for each patient. Relevant medical data were extracted from patients' hospital files. RESULTS: Of the enrolled patients, 122 were included in the statistical analyses. The severity of periodontitis was directly and significantly correlated with the severity of COVID-19 (P < 0.001). Patients with generalized stage III or IV periodontitis displayed an adjusted odds ratio of 4.24 for severe to critical COVID-19. Salivary and serum interleukin-6 levels were significantly associated with COVID-19 severity (P values: 0.002 and 0.004, respectively). Hospitalization length was significantly associated with the severity of periodontitis (P = 0.004). Clinical attachment level and gingival index were associated with increased odds for adverse events (P values: 0.004 and 0.035, respectively), while number of remaining teeth was associated with decreased odds for adverse events (P = 0.023). CONCLUSIONS: This study showed that the severity of periodontitis is associated with the severity of COVID-19. This association might manifest as increased odds of adverse events. COVID-19 severity was associated with higher levels of salivary and serum interleukin-6 levels.

Hematologic tests and their association with the severity of COVID-19 and periodontitis in hospitalized patients: a case-control study.

BACKGROUND: The presence of comorbidities, especially those with a chronic inflammatory nature such as periodontitis, can facilitate COVID-19 progression toward more severe forms. Both of these diseases can affect systemic health and alter hematological test results. In this study, we decided to investigate COVID-19 and periodontitis' possible interaction with these alterations. METHODS: Hospitalized patients with a definitive diagnosis of COVID-19 were included. Controls had mild to moderate COVID-19, while cases had severe to critical COVID-19. Periodontal examination was done for each patient. Relevant medical and hematological data were extracted from patient's hospital files. RESULTS: A total of 122 patients entered the final analysis. The minimum white blood cell counts were associated with the severity of periodontitis. The interaction between periodontitis and COVID-19 was associated with increased minimum white blood cell counts and decreased platelet counts. COVID-19 severity was associated with increased venous oxygen saturation, prothrombin time, the maximum partial thromboplastin time, the maximum and average urea, the maximum creatinine, the maximum potassium, and lactate dehydrogenase, and decreased sodium levels. CONCLUSIONS: Results of this study showed that several blood parameters were associated with periodontitis, COVID-19, or the interaction between them.

Comparison of Pulsed and Continuous Wave Diode Laser at 940 nm on the Viability and Migration of Gingival Fibroblasts.

Gingival fibroblasts have critical roles in oral wound healing. Photobiomodulation (PBM) has been shown to promote mucosal healing and is now recommended for managing oncotherapy-associated oral mucositis. This study examined the effects of the emission mode of a 940 nm diode laser on the viability and migration of human gingival fibroblasts. Cells were cultured in a routine growth media and treated with PBM (average power 0.1 W cm-2 , average fluence 3 J cm-2 , every 12 h for six sessions) in one continuous wave and two pulsing settings with 20% and 50% duty cycles. Cell viability was assessed using MTT, and digital imaging quantified cell migration. After 48 and 72 h, all treatment groups had significantly higher viability (n = 6, P < 0.05) compared with the control. The highest viability was seen in the pulsed (20% duty cycle) group at the 72-h time point. PBM improved fibroblast migration in all PBM-treated groups, but differences were not statistically significant (n = 2, P > 0.05). PBM treatments can promote cell viability in both continuous and pulsed modes. Further studies are needed to elucidate the optimal setting for PBM-evoked responses for its rationalized use in promoting specific phases of oral wound healing.

Effectiveness of using platelet-rich fibrin to increase keratinized tissue around the tooth in the modified apical reposition flap method: A split-mouth, randomized controlled trial.

OBJECTIVES: One of the simplest methods to increase keratinized gingiva is the modified apically repositioned flap (MARF) technique. In this method, the periosteum remains exposed, which may lead to postoperative pain and discomfort. In the presence of bone dehiscence, bone resorption and gingival recession may occur. Hence, this study aims to use platelet-rich fibrin (PRF) to promote wound healing in the MARF technique and overcome its disadvantages. MATERIAL AND METHODS: In this randomized controlled trial study, 10 patients (six males and four females with a mean age of 33.9 ± 11.13) with less than 2 mm of attached gingiva bilaterally were treated by the MARF + PRF membrane (test group), on the one hand, whereas, on the other hand, it was treated only by MARF (control group). Clinical parameters of keratinized gingiva include thickness, width, and vestibule depth before and 8 weeks after the intervention were measured. RESULTS: The attached gingival width increased significantly in both groups (1.7 mm in the MARF and 2.3 mm in the PRF) and this was greater in the PRF group (p < .05). Gingival thickness in the PRF method was significantly higher than in the control group (p < .05). Probe depth, vestibular depth, and postoperative pain were not different in both groups. Wound shrinkage in the MARF group (51%) was significantly higher than in the PRF group (30%) (p < .05). CONCLUSION: Using PRF with the MARF method significantly increased the width and thickness of the gingiva and reduced shrinkage compared to MARF only. Postoperative pain and vestibular depth changes were similar in both groups.

Clinical evaluation of chitosan/polycaprolactone nanofibrous scaffolds releasing tetracycline hydrochloride in periodontal pockets of patients with chronic periodontitis.

Background: The role of bacteria in the initiation and progression of periodontitis has led to a great interest in using antibiotics to suppress pathogenic microbiota. Considering the drawbacks of systemic antibiotics' application, local delivery systems directly in the periodontal pocket can be helpful. Therefore, the effect of an efficient tetracycline-loaded delivery system was investigated on the clinical parameters of periodontitis. Methods: In this clinical trial with a split-mouth design, 10 patients with periodontitis with pocket depths≥5 mm were included. After scaling and root planing (SRP) for all the patients, one side of the mouth was randomly considered as the control group, and on the other side, chitosan/polycaprolactone (PCL) nanofibrous films containing tetracycline (5%) were placed in pockets of 5 mm and deeper. Clinical measurements of pocket probing depth (PPD), clinical attachment loss (CAL), and bleeding on probing (BOP) indices were made at the beginning and after 8 weeks of intervention. PPD, CAL, and BOP parameters were compared between the control and test groups before and after the intervention with paired t tests using SPSS 24. The significance level of the tests was considered at P<0.05. Results: The mean PPD, CAL, and BOP in both the control (SRP) and test (LDDs) groups decreased after 8 weeks. A significant difference was detected in reducing PPD, BOP, and CAL after 8 weeks in 5-mm pockets, and the mean values were higher in the test group than in the control (P<0.05). Conclusion: The local drug delivery system using chitosan/PCL nanofibrous films containing tetracycline can effectively control periodontal diseases by reducing pocket depth and inflammation and improving CAL without offering side effects, although further evaluations are needed.

Efficacy of the Er,Cr:YSGG Laser Application Versus the Conventional Method in Periodontal Flap Surgery: A Split-Mouth Randomized Control Trial.

Introduction: the Er,Cr:YSGG laser has a suitable wavelength for the ablation of both hard and soft tissues of the periodontium and can be considered as a potential tool in periodontal surgeries. The current study aimed at evaluating the application of this laser versus conventional instruments in periodontal pocket reduction flap surgery. Methods: Eight patients (16 dental arches) requiring periodontal surgery were included (Trial registration number: IRCT201711129014N199). Using a split-mouth study design, two posterior sextants of a dental arch were randomly allocated into either a test group, open flap debridement periodontal surgery using the Er,Cr:YSGG laser or a control group using the conventional method. Laser parameter settings of a 2780 nm wavelength, H mode (60 µs pulse duration), 25-50 Hz, 2-3.5 W output powers and Air-20%, Water-60-80% were applied and adjusted individually for each step of the flap surgery procedure. Baseline, 1 and 3-month measurements of plaque index (PI), Gingival Index (GI), gingival recession (GR), probing depth (PD) and clinical attachment level (CAL) were recorded for comparisons. Data were analyzed by a linear model for correlated data using the generalized estimating equations (GEE) method and the least significant difference (LSD). Results: In both treatment groups, reductions in PI and GI were observed in the 3-month follow-up period. These indices were significantly lower in the laser-treated sides compared to the conventional group (P<0.05). The Mean PD and CAL were lower at 1 month and 3 months compared to the baseline in both groups (P<0.05). However, these parameters were not statistically different in the treatment groups during these follow-up timelines. An increase in GR was observed from the baseline to 1 month and 3 months with less recession in the laser-treated sides (P=0.016). Conclusion: Based on the results of the present study, the Er,Cr:YSGG laser assisted periodontal flap surgery resulted in similar treatment outcomes to the conventional method and may be considered as a safe and effective treatment modality.

A decision support system based on support vector machine for diagnosis of periodontal disease.

OBJECTIVE: Early diagnosis of many diseases is essential for their treatment. Furthermore, the existence of abundant and unknown variables makes more complicated decision making. For this reason, the diagnosis and classification of diseases using machine learning algorithms have attracted a lot of attention. Therefore, this study aimed to design a support vector machine (SVM) based decision-making support system to diagnosis various periodontal diseases. Data were collected from 300 patients referring to Periodontics department of Hamadan University of Medical Sciences, west of Iran. Among these patients, 160 were Gingivitis, 60 were localized periodontitis and 80 were generalized periodontitis. In the designed classification model, 11 variables such as age, sex, smoking, gingival index, plaque index and so on used as input and output variable show the individual's status as a periodontal disease. RESULTS: Using different kernel functions in the design of the SVM classification model showed that the radial kernel function with an overall correct classification accuracy of 88.7% and the overall hypervolume under the manifold (HUM) value was to 0.912 has the best performance. The results of the present study show that the designed classification model has an acceptable performance in predicting periodontitis.

Relationship between dental plaque formation and salivary cortisol level in pregnant women.

PURPOSE: Understanding how increased level of salivary cortisol contributes to the development of dental biofilm during pregnancy can help inthe prevention of dental caries and periodontal diseases. This study aims to evaluate the relationship between salivary cortisol level and dental biofilm formation in pregnant women. PATIENTS AND METHODS: This descriptive-analytic study was conducted in Hamadan, Iran in 2011. Forty consecutive pregnant women with no history of abortion, stillbirth, or any known physical or psychological disorders at weeks 25 and 33 of gestation were included. Salivary samples were collected for measurement of cortisol levels by Enzyme Linked Immunoabsorbent Assay (ELISA) method. The amount and extension of dental biofilms were determined by using a disclosing agent. Data were analyzed using descriptive and analytical statistics in SPSS version 16. RESULTS: The mean levels of salivary cortisol at weeks 25 and 33 of gestation were respectively, 2.45 ± 1.56 µg/dl and 5.24 ± 4.07 µg/dl which demonstrates a significant difference (P<0.001). Evaluation of dental biofilm at two time intervals revealed a significant increase in amount of dental biofilm at week 33 of gestational period (34.65 ± 10.9% vs. 42.45 ± 12.35%, P<0.001). Elevated levels of dental biofilm were significantly correlated with salivary cortisol levels at week 33 (r=0.494, P=0.001),however, it was not significant at week 25 of gestation (r=0.148, P=0.361). CONCLUSION: The findings suggested that increased levels of salivary cortisol can predict dental biofilm formation and accumulation in pregnant women in the last weeks of gestation.

Effect of Implant-Abutment Connection Type on Stress Distribution in Peri-Implant Bone and Abutment Micromovement: A Three-Dimensional Finite Element Analysis.

This study assessed the effect of implant-abutment connection type on stress distribution in peri-implant bone and abutment micromovement using finite-element analysis (FEA). Dimensions of three implant-abutment designs were measured by a three-dimensional scanner and transferred to SOLIDWORKS. An elemental model was designed using ABAQUS. Each implant was placed in bone at the crestal level. A 100-N load was applied at a 45° angle relative to the longitudinal axis of the implant in the buccolingual direction from the palatal toward the buccal and coronal parts of the abutment. Shear stress, von Mises stress, and micromovement of the abutment relative to the fixture were analyzed. Data were reported qualitatively and quantitatively using ABAQUS. The von Mises stress in all three samples decreased from the crest toward the apical area and was distributed homogenously. Maximum stress concentration was at the most coronal part of the implant body in the midbuccal area. In cancellous and cortical bone, stress decreased from the crest toward the palate and was at its maximum at the midbuccal point in the bone crest. Stress in cortical bone was more homogenous and in cancellous bone was higher. Shear stress was higher in the buccal than in the palatal area, and at its maximum shear stress and equal in the mesiobuccal and distobuccal areas. Micromovement was 4.25 µm in an Astra implant, 5.42 µm in a Intra-Lock implant, and 6.63 µm in an SPI implant. The distribution of von Mises and shear stress was the same in bone around the three implant connection types; however, abutment micomovement differed.

Effect of Er,Cr (YSGG Laser Root Conditioning on the Success of Root Coverage with Subepithelial Connective Tissue Graft): A Randomized Clinical Trial with a 6-Month Follow-Up.

OBJECTIVES: Finding predictable approaches for root surface biomodification is an important challenge in the treatment of gingival recession. This study sought to assess the root coverage percentage by subepithelial connective tissue graft (SCTG) following root surface conditioning with erbium, chromium: yttrium scandium gallium garnet (Er,Cr:YSGG) laser. MATERIALS AND METHODS: In this split-mouth, randomized clinical trial, 30 teeth with Miller's Class I and II gingival recession were treated with SCTG (the Langer and Langer technique) with (case group) or without (control group) root surface conditioning with Er,Cr:YSGG laser (wavelength=2780 nm, power=0.75 W, H mode, repetition rate=20 Hz). Recession depth (RD), recession width (RW), clinical attachment level (CAL), and probing depth (PD) were assessed at the baseline (one week before surgery) and at 2 and 6 months postoperatively. The amount of root coverage was quantified in the two groups. Data were analyzed using Friedman test and Wilcoxon signed-rank test. RESULTS: No significant difference was noted between the case and control groups in any parameter (P>0.05). Significant improvement occurred in all the measured parameters in the two groups after surgery (P<0.05). The mean root coverage at the end of the study period was 87% and 80% in the case and control groups, respectively (P=0.244), and complete root coverage was achieved in 66% and 60% of the samples in the case and control groups, respectively. CONCLUSIONS: Root surface conditioning by Er,Cr:YSGG laser improved the mean root coverage and the percentage of complete root coverage. However, these changes were not statistically significant.

Low-level laser therapy with 940 nm diode laser on stability of dental implants: a randomized controlled clinical trial.

Low-level laser therapy (LLLT) is a non-invasive modality to promote osteoblastic activity and tissue healing. The aim of this study was to evaluate the efficacy of LLLT for improvement of dental implant stability. This randomized controlled clinical trial was performed on 80 dental implants placed in 19 patients. Implants were randomly divided into two groups (n = 40). Seven sessions of LLLT (940 nm diode laser) were scheduled for the test group implants during 2 weeks. Laser was irradiated to the buccal and palatal sides. The same procedure was performed for the control group implants with laser hand piece in "off" mode. Implant stability was measured by Osstell Mentor device in implant stability quotient (ISQ) value immediately after surgery and 10 days and 3, 6, and 12 weeks later. Repeated measures ANOVA was used to compare the mean ISQ values (implant stability) in the test and control groups. Statistical test revealed no significant difference in the mean values of implant stability between the test and control groups over time (P = 0.557). Although the mean values of implant stability changed significantly in both groups over time (P < 0.05). Although the trend of reduction in stability was slower in the laser group in the first weeks and increased from the 6th to 12th week, LLLT had no significant effect on dental implant stability.

Efficacy of Application of Platelet-Rich Fibrin for Improvement of Implant Stability: A Clinical Trial.

Use of platelet concentrates to increase implant stability, due to their regenerative potential, has recently attracted the attention of researchers. This study aimed to assess the effect of platelet-rich fibrin (PRF) on dental implant stability. This clinical trial evaluated 10 patients who received 50 dental implants. Each patient received at least two implants. Half of the implants were placed in the sockets along with PRF while the remaining half were inserted conventionally without PRF. Implant stability was measured by resonance frequency analysis on the day of surgery (T1), at one week (T2), and at one month (T3). At the end of the first week (T2), the mean implant stability quotient (ISQ) was 59.85 ± 5.32 in the PRF group and 55.99 ± 3.39 in the non-PRF group. Compared to baseline, the ISQ increased in the PRF group by 0.12 ± 0.47 (P = 1.000) and decreased in the non-PRF group by 2.42 ± 0.36 (P < 0.001). At one month postoperatively, ISQ significantly increased by 6.89 ± 0.96 in the PRF group and by 4.82 ± 0.92 in the non-PRF group compared to baseline (P < 0.001). Application of PRF in the implant osteotomy site can prevent or minimize primary reductions in implant stability and seems to enhance the process of osseointegration.

CO2 laser surface treatment of failed dental implants for re-implantation: an animal study.

The aim of the present study was to evaluate the success rate of failed implants re-implanted after surface treatment with CO2 laser. Despite the widespread use of dental implants, there are many incidents of failures. It is believed that lasers can be applied to decontaminate the implant surface without damaging the implant. Ten dental implants that had failed for various reasons other than fracture or surface abrasion were subjected to CO2 laser surface treatment and randomly placed in the maxillae of dogs. Three failed implants were also placed as the negative controls after irrigation with saline solution without laser surface treatment. The stability of the implants was evaluated by the use of the Periotest values (PTVs) on the first day after surgery and at 1, 3, and 6 months post-operatively. The mean PTVs of treated implants increased at the first month interval, indicating a decrease in implant stability due to inflammation followed by healing of the tissue. At 3 and 6 months, the mean PTVs decreased compared to the 1-month interval (P < 0.05), indicating improved implant stability. The mean PTVs increased in the negative control group compared to baseline (P < 0.05). Independent t-test showed that the mean PTVs of treated implants were significantly lower than control group at 3 and 6 months after implant placement (P < 0.05). Based on the PTVs, re-implantation of failed implants in Jack Russell Terrier dogs after CO2 laser surface debridement is associated with a high success rate in terms of implant stability.

A Comparative Study of Clinical Parameters in Submerged and Non submerged Implants.

AIM: The aim of this study was to evaluate and compare the radiographic bone loss and soft tissue parameters around one stage and two stage implants. MATERIALS AND METHODS: Twenty four patients with submerged implants and twenty four patients with non submerged implants at the time of loading were assessed in this prospective cohort study. The soft tissue assessment included probing depth (PD), papilla index (PI), mucosal thickness (MT) and keratinized tissue (KG); another parameter assessed was the radiographic distance between the shoulder of the implant and alveolar crest evaluated at baseline (loading time) and 3,6 and 12 months after loading in both groups.Data were analysed using repeated measures analysis of variance (ANOVA) and multiple comparisons were done using LSD method. RESULTS: The changes in the soft tissues including PD, KG, MT and PI had no significant differences in either group. The amount of bone loss 3 and 6 months after loading was significantly greater in one stage implants (0.93±0.45 mm at 3months and1.45±0.58 mm at 6months, for one stage and 0.32±0.21 mm at 3months and 0.74±0.43 mm at 6 months for two stage group). But the change of this index 12 months later was not significantly different between the two groups (1.87±0.76mm for one stage and 1.65±0.59mm for two stage group). CONCLUSION: Based on the results of this study there is no difference in hard and soft tissue changes one year after loading of one or two stage implants.

The Efficacy of Brushing and Flossing Sequence on Control of Plaque and Gingival Inflammation.

PURPOSE: To evaluate the efficacy of brushing and flossing order on control of plaque and gingival inflammation. MATERIALS AND METHODS: This cross-over clinical trial was conducted on 35 students recruited from the dental school at Hamadan University of Medical Sciences. The subjects were asked to use dental floss and then brush for a 2-week period (FB), followed by brushing and then using dental floss for another 2-week period (BF). For a 7-day washout interval between the two phases, the subjects practiced dental hygiene according to their habitual method. The participants received dental prophylaxis at the beginning and plaque control record (PCR), plaque index (PI) and bleeding point index (BPI) were measured at baseline and the end of both phases. The differences of indices between two phases were analysed with the Wilcoxon signed rank test; to assess the influence of sex and sequence on PCR, PI and BPI, analysis of covariance (ANCOVA) was used after adjustment of initial values. RESULTS: The PCR and PI indices in the FB method were significantly lower than with the BF method (P < 0.05). The PI and PCR index differences between the two phases were significant in men but nonsignificant in women. The effect of gender on PI and BPI and the interaction effect of sex and sequence of brushing and flossing on BPI were significant (P < 0.05). CONCLUSIONS: Flossing followed by brushing provides more statistically significant improvements over brushing followed by flossing with respect to plaque control.

Reduction of Melatonin Level in Patients with Type II Diabetes and Periodontal Diseases.

Background and aims. Melatonin is a circulating hormone that is mainly released from the pineal gland. It possesses antioxidant, free-radical scavenging, and immune-enhancing properties. A growing number of studies reveal a complex role for melatonin in influencing various diseases, including diabetes and periodontal diseases. The aim of this study was to examine the possible links between salivary melatonin levels and type II diabetes and periodontal diseases. Materials and methods. A total of 30 type II diabetic patients, 30 patients with periodontal diseases, 30 type II diabetic patients with periodontal disease and 30 age- and BMI-matched controls were studied. The periodontal status was evaluated by the Community Periodontal Index (CPI). Salivary melatonin levels were determined by a commercial enzyme-linked immunosorbent assay (ELISA) kit. Results. The mean of salivary melatonin level was significantly lower in patients with either periodontitis or diabetes compared to healthy subjects (P < 0.05). Salivary melatonin concentration decreased in type II diabetic patients and periodontitis patients, and then decreased reaching the lowest levels in type II diabetic patients with periodontal disease. Conclusion. Based on the results of this study, it can probably be concluded that salivary level of melatonin has an important role in the pathogenesis of diabetes and periodontal diseases. It is also worth noting that this factor could probably be used as a pivotal biological marker in the diagnosis and possible treatment of these diseases, although further research is required to validate this hypothesis.

Effect of rheumatoid arthritis on periodontitis: a historical cohort study.

PURPOSE: Rheumatoid arthritis (RA) is a chronic multi-systemic disease that causes damage to the bone and connective tissues. This study was conducted in order to accurately measure the correlation between RA and periodontitis, and to obtain an unbiased estimate of the effect of RA on periodontal indices. METHODS: In this historical cohort study, which was conducted from February to May 2011 in Hamadan city, Iran, 53 exposed people (with RA) were compared with 53 unexposed people (without RA) in terms of clinical periodontal indices (the outcomes of interest) including 1) plaque index (PI), 2) bleeding on probing (BOP), and 3) clinical attachment loss (CAL). RESULTS: A sample of 106 volunteers were evaluated, 53 rheumatoid versus 53 non-rheumatoid subjects. There was a statistically significant correlation between RA and BOP (P<0.001) and between RA and CAL (P<0.001). However, there was no statistically significant correlation between RA and any of the periodontal indices. No correlation was seen between gender and any of the indices either. There was a strong positive correlation between age and all three periodontal indices (P<0.001). CONCLUSIONS: The present study indicated a potential effect of RA on periodontal indices. However, much more evidence based on a prospective cohort study is needed to support the cause and effect relationship between RA and periodontal indices.