Role of TNF-α and Its Receptors in Pericoronitis

The Significance of Oral Inflammation in Elite Sports: A Narrative Review

Recently, there has been intense discussion about sports dentistry and potential interactions between oral health and athletes' performance. This narrative review aims to provide a comprehensive overview of the available literature about oral inflammation in sports. For this purpose, it presents the most common types of oral inflammation (gingivitis, periodontitis, pericoronitis, apical periodontitis), and their prevalence in athletes. Both the impact of oral inflammation on performance and causes for oral inflammation in athletes are discussed by presenting current literature. Finally, international recommendations for dental care in sports are presented. Several studies stated a high prevalence of oral inflammation in athletes, especially of gingivitis (58-97%) and periodontitis (41%). Also, many athletes report oral pain (17-30%) and a negative impact of oral health on training (3-9%). Besides this, a systemic impact of oral inflammation is discussed: In periodontitis patients, blood parameters and physical fitness are changed. In athletes, associations between muscle injuries and poor oral health are reported. There are deficits in oral health behavior. Furthermore, systemic changes due to physical stress could influence oral tissues. Overall, complex bidirectional interactions between competitive sports and oral inflammation are possible. Regular dental examinations and prevention strategies should be implemented in sports.

The Correlation between Impacted Third Molar and Blood Group

Background

Blood type is among the most important genetical characteristics of any individual and is shown to be correlated with the development of a variety of illnesses including dental diseases. Finding the association of ABO and Rh blood groups and impacted tooth is important in order to predict which population is more vulnerable to grow impacted third molars that could lead to making better intervention. The present investigation tried to take a small step in that regard, by evaluating the correlation between ABO and Rh blood groups and the most commonly impacted tooth, bony impacted third molars among Iranian individuals.

Methods

The investigation was done retrospectively on patients who were referred to the Department of Oral Radiology, Shiraz University of Medical Science, Shiraz, Iran. The patients were classified according to their blood groups, and 40 patients were randomly selected for each blood type. Therefore, the impaction of their third molars was evaluated, and statistical analyses were done in order to find any association.

Results

A total of 320 participants contributed to the study; 136 (42%) were males and 184 (57%) were females. The mean age was 29 ± 6 years. Among all participants, 205 (64%) had no impacted third molar, 26 (8%) had one impacted third molar, 43 (13%) had 2 impacted third molars, 5 (1%) had 3 impacted third molars, and 41 (12%) had 4 impacted molars.

Conclusion

According to the results of the present study, nearly one out of three individuals has at least an impacted third molar in the Iranian population, being more prevalent in individuals between 20 and 30 years old. The evaluation of the relationship between the blood group and impacted third molar revealed that blood groups have no association with the impacted third molars. However, more studies with higher and diversified participants should be done to find comprehensive results.

Evaluation of photodynamic therapy in pericoronitis: Protocol of randomized, controlled, double-blind study

INTRODUCTION

Pericoronitis is a common disease in the eruption phase of third molars, sometimes debilitating, with an impact on the quality of life. The most indicated treatment in the initial phase is the irrigation for cleanliness of the region. In order to reduce the chances of systemic dissemination of the infection and antibiotics use, it is mandatory to test effective treatments in the initial phase of pericoronitis avoiding the evolution of the infectious disease. Photodynamic therapy (PDT) is an interesting alternative because it is an effective antimicrobial treatment that is easy to perform and does not select bacterial resistance. The methylene blue (MB) used in PDT has been studied in an oral formulation, which optimizes the formation of monomers increasing its antimicrobial action.

OBJECTIVE

The aim of this study is to evaluate the effectiveness of PDT with MB in an astringent vehicle in pericoronitis on the initial phase in healthy patients through microbiological, clinical, and immune response. The impact of pericoronitis on oral health-related quality of life (OHRQoL) of these patients will also be evaluated.

METHOD

In this randomized, controlled, double-blind clinical bioequivalence protocol, 64 healthy patients with pericoronitis will be evaluated. Patients will be randomized into the positive control group (G1) (n = 32): irrigation with sterile saline and PDT (conventional MB at 0.005% concentration and irradiation with low intensity laser λ = 660 nm, 9J per point and radiant exposure of 318 J/cm), and the experimental group (G2) (n = 32): treatment identical to G1, however, MB will be delivered in a new formulation for oral use. Microbiological analysis will be performed by RT-PCR for the bacterium Tannerella forsythia. Gingival crevicular fluid and saliva will be collected to evaluate cytokines by Luminex assay (Luminex Corporation, Austin, TX). The pain (visual analogue scale), swelling and buccal opening (digital caliper), and OHRQoL will also be evaluated through the OHIP-14 questionnaire. The variables will be evaluated in T1 (baseline), T2 (immediately after PDT), and T3 (4th day after PDT). Registration: clinicaltrials.gov NCT03576105. Registered in July 2018.

Expression of matrix metalloproteinases-2, -9 and reversion-inducing cysteine-rich protein with Kazal motifs in gingiva in periodontal health and disease

BACKGROUND AND OBJECTIVE

Periodontitis is characterized by pathological destruction of extracellular matrix (ECM) of periodontal tissues. Matrix metalloproteinases (MMPs) promote the occurrence and development of periodontitis by degrading almost all proteins of ECM. RECK (reversion-inducing-cysteine-rich protein with kazal motifs), a novel membrane-anchored inhibitor of MMPs, could regulate the expression of MMP-2 and MMP-9 at post-transcriptional level. The study was to investigate the expression of RECK in healthy and diseased human gingival tissues and to correlate it with the production of MMP-2 and MMP-9.

MATERIAL AND METHODS

Gingival biopsies were collected from chronic periodontitis patients and periodontally healthy control individuals. The protein and mRNA of RECK, MMP-2 and MMP-9 was determined by immunohistochemistry and semi-quantitative polymerase chain reaction analysis.

RESULTS

The expression of RECK protein was mainly confined to the gingival epithelium in inflamed and non-inflamed gingival tissues. Expression of RECK was significantly lower in tissues from chronic periodontitis patients, while the positive expression levels of MMP-2 and MMP-9 in periodontitis specimens were significantly higher. RECK protein expression was negatively correlated to the expressions of MMP-2 and MMP-9 in periodontitis. Moreover, RECK mRNA was significanly lower in diseased gingiva than in healthy samples(P<0.05), while MMP-2 and MMP-9 mRNAs were observed overexpressed in periodontal lesions, with no significant correlation between RECK and MMP-2/MMP-9 mRNA shown in periodontally diseased group.

CONCLUSION

The expression of RECK in human healthy and diseased gingiva may contribute to periodontal physiological and pathological processes; low RECK expression may be associated with the enhanced MMP-2 and MMP-9 production in inflamed gingiva.

Common Matrix Metalloproteinases (MMP-8, -9, -25, and -26) Cannot Explain Dentigerous Cyst Expansion

OBJECTIVE

Mechanisms of the dentigerous cyst formation from the normal eruption follicle is unknown but disturbances in the proteolytic activity have been suspected, since the growth of these cysts is accompanied by local bone destruction. The aim of the present study was to evaluate the expression of matrix metalloproteinases (MMP) in human dental dentigerous cysts and healthy dental follicles.

MATERIALS AND METHODS

We studied 10 patients with dentigerous cysts and 10 healthy dental follicles from the lower jaw in respect to their immunoexpression of MMPs -8, -9, -25, and -26 and tissue inhibitor of metalloproteinases -1 (TIMP-1).

RESULTS

MMP-8 was expressed slightly more in cyst epithelium than in odontogenic epithelium of healthy controls dental follicle but the difference lacked statistical difference. Other MMPs and TIMP-1 did not differ regarding the studied specimens.

CONCLUSION

Differences in MMP expression cannot solely explain the cyst expansion suggesting the potential involvement of other osteolytic mechanisms.

A comparative histological and immunohistochemical study of wound healing following incision with a scalpel, CO2 laser or Er,Cr:YSGG laser in the guinea pig oral mucosa

PURPOSE

This study was undertaken to compare wound healing following incisions with either a scalpel, CO(2) laser or Er,Cr:YSGG laser in Guinea pig oral mucosa.

MATERIALS AND METHODS

Three types of wounds were randomly introduced with either a stainless steel scalpel, CO(2) laser or Er,Cr:YSGG laser in the buccal mucosa of each of 22 Guinea pigs. Four Guinea pigs were sacrificed on day 1, day 3 and day 5 post-surgery. Five Guinea pigs were sacrificed on day 7 and day 14 post-surgery. Biopsy samples from each oral mucosa wound were examined and the expression of TNF-α and TGF-ß1 was determined by immunohistochemical staining.

RESULTS

At day 3 post-surgery, the histological pattern of the healing process was similar in the scalpel and Er,Cr:YSGG laser wounds and there were more ulcerations present in the CO(2) laser wounds than in the scalpel and Er,Cr:YSGG laser wounds. The level of TNF-α expression was twice in the laser wounds that in the scalpel wounds. A higher level of TGF-β1 expression was seen at day 7 post-surgery and a lower level at day 14 post-surgery in the CO(2) laser wounds than in the scalpel and Er,Cr:YSGG laser wounds.

CONCLUSIONS

The Er,Cr:YSGG laser has many advantages for oral surgery due to a low inflammatory response and minimal damage of the tissue. Although a CO(2) laser has better hemostatic ability, its use causes greater tissue damage than a scalpel and Er,Cr:YSGG laser. However, further larger studies would be needed before fully endorsing its widespread use.

Azithromycin may inhibit interleukin-8 through suppression of Rac1 and a nuclear factor-kappa B pathway in KB cells stimulated with lipopolysaccharide

BACKGROUND

Recent studies have shown that the 15-member macrolide antibiotic azithromycin (AZM) not only has antibacterial activity, but also results in the role of immunomodulator. Interleukin (IL)-8 is an important inflammatory mediator in periodontal disease. However, there have been no reports on the effects of AZM on IL-8 production from human oral epithelium. Therefore, we investigated the effects of AZM on IL-8 production in an oral epithelial cell line.

METHODS

KB cells were stimulated by Escherichia coli or Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) lipopolysaccharide (LPS) with or without AZM. IL-8 mRNA and protein expression and production in response to LPS were analyzed by quantitative polymerase chain reaction, flow cytometry, and enzyme-linked immunosorbent assay. The activation of nuclear factor-kappa B (NF-κB) and Rac1, which is important for IL-8 expression, was analyzed by enzyme-linked immunosorbent assay and Western blotting, respectively.

RESULTS

IL-8 mRNA expression, IL-8 production, and NF-κB activation in LPS-stimulated KB cells were inhibited by the addition of AZM. LPS-induced Rac1 activation was also suppressed by AZM.

CONCLUSIONS

This study suggests that AZM inhibits LPS-induced IL-8 production in an oral epithelial cell line, in part caused by the suppression of Rac1 and NF-κB activation. The use of AZM might provide possible benefits in periodontal therapy, with respect to both its antibacterial action and apparent anti-inflammatory effect.

Comparison of periodontal inflammatory disease in young adults with and without pericoronitis involving mandibular third molars

PURPOSE

To compare the prevalence and severity of periodontal inflammatory disease in subjects with pericoronitis involving a mandibular third molar and those without pericoronitis.

PATIENTS AND METHODS

Data obtained from healthy adults consecutively enrolled in an institutional review board-approved trial with pericoronitis affecting at least 1 mandibular third molar (study group) were compared with data obtained during the same time frame from subjects without pericoronitis enrolled in a longitudinal third molar monitoring study (comparison group). The periodontal status of each subject was classified based on periodontal probing depths (PD): all PD <4 mm, no disease; 1 to 3 PD >or=4 mm, incipient disease; at least 4 PD >or=4 mm, early disease. Full mouth periodontal probing data were obtained as clinical measures of periodontal status. Data were aggregated to the subject level for the third molar region, the 6 third molar probing sites and the 2 second molar distal probing sites, the non-third molar region, and all remaining probing sites. The prevalence of disease in the study and comparison groups were compared with the Fisher's exact test. As an indicator of disease severity, the number of PD >or=4 mm in the 2 groups were compared by the Kruskal-Wallis test. Level of significance was set at P values less than .05.

RESULTS

Median age of the 56 subjects with pericoronitis was 23.3 years (IQR 21.3-26.0 years). Fifty-five percent were Caucasian, 16% African American, and 22% Asian. Males and females were almost equally represented in the study group and in the comparison group. The 194 subjects enrolled without pericoronitis were significantly older (32.8 years; IQR 27.2-40.0 years; P < .001). Eighty-four percent were Caucasian, 10% African American, and 4% Asian. The proportion of subjects with periodontal inflammatory disease in the third molar region was significantly different between the study and comparison groups. Thirty-one percent of the subjects with pericoronitis had incipient and 55% early disease in the third molar region compared with 25% with incipient and 38% with early disease among subjects without pericoronitis (P = .003). The pattern was similar, but the proportion of subjects was not significantly different between the groups for the non-third molar region. In the study group, 32% had incipient disease and 32% early disease compared with 27% with incipient disease and 22% with early disease in the comparison group (P = .09). The median number of PD >or=4 mm for all teeth differed significantly for subjects with and without pericoronitis (median 5 [IQR 3-9] vs 3 [IQR 0-8], respectively; P = .03).

CONCLUSION

Pericoronitis involving mandibular third molars may reflect more underlying periodontal inflammatory disease in affected young adults than might be found in young adults with retained third molars and no pericoronitis.

Matrix metalloproteinases: contribution to pathogenesis, diagnosis and treatment of periodontal inflammation

Matrix metalloproteinases (MMPs) form a family of enzymes that mediate multiple functions both in the tissue destruction and immune responses related to periodontal inflammation. The expression and activity of MMPs in non-inflamed periodontium is low but is drastically enhanced to pathologically elevated levels due to the dental plaque and infection-induced periodontal inflammation. Soft and hard tissue destruction during periodontitis and peri-implantitis are thought to reflect a cascade of events involving bacterial virulence factors/enzymes, pro-inflammatory cytokines, reactive oxygen species and MMPs. However, recent studies suggest that MMPs can also exert anti-inflammatory effects in defence of the host by processing anti-inflammatory cytokines and chemokines, as well as by regulating apoptotic and immune responses. MMP-inhibitor (MMPI)-drugs, such as doxycycline, can be used as adjunctive medication to augment both the scaling and root planing-treatment of periodontitis locally and to reduce inflammation systematically. Furthermore, MMPs present in oral fluids (gingival crevicular fluid (GCF), peri-implant sulcular fluid (PISF), mouth-rinses and saliva) can be utilized to develop new non-invasive, chair/bed-side, point-of-care diagnostics for periodontitis and dental peri-implantitis.