Other

OBJECTIVES:

The purpose of this in vitro study was by using quantitative real-time PCR and culturing to determine the effectiveness of two irrigation and cleaning systems in removing multispecies oral biofilms from root canals.

MATERIAL AND METHODS:

Twenty extracted human molars were instrumented to size #15/.02 and then cleaned with the GentleWave (GW) System. The teeth were autoclaved to provide the same sterile baseline. The molars were filled with mixed plaque suspended in BHI and centrifuged to inoculate the biofilms. After 2 weeks of incubation, the teeth were randomly divided into two treatment groups. In GW group (26 canals), the teeth were further instrumented to size #15/04, and in PiezoFlow (PF) group (30 canals) to #35/.04. The teeth were then cleaned either with GW System or ProUltra PiezoFlow Active Ultrasonic System using 3% sodium hypochlorite NaOCl, 8% EDTA, and sterile water as irrigants. Samples (S1, S2, and S3) for bacterial cultures were taken from 13 canals before and after instrumentation and after final cleaning. Quantitative real-time PCR was performed from all 56 canals, and universal bacterial, one genus, and one species-specific primers were used to determine the presence of microorganisms in samples from root canals before and after instrumentation and after final cleaning. Statistical analyses were performed using the Mann-Whitney U test with the significance level set at P < 0.05.

RESULTS:

Bacterial culturing from the canal samples revealed strong reduction of bacteria from S1 to S2 in both groups after instrumentation and irrigation with water only. No growth was detected in any of the S3 samples after cleaning in either group. A highly significant reduction in bacterial DNA was recorded by qPCR for both groups (P < 0.001). GW System showed more constant and a significantly higher reduction of total microbial DNA (P = 0.007), Enterococcus faecalis DNA (P = 0.011) and Streptococcus spp. DNA (P = 0.029) than the Ultrasonic System. The amount of residual microbial DNA calculated as an average of residual DNA in each individual canal in PF group was 1.99% and in GW group 0.09%.

CONCLUSIONS:

While both systems demonstrated a highly effective reduction of intracanal bacterial DNA, the final total amount and variation in the number of residual bacterial DNA was significantly smaller in the GW group.

CLINICAL RELEVANCE:

Elimination of microbes from the infected root canal system is regarded as the key for long-term clinical success. While both GentleWave and Ultrasonic Systems used with NaOCl and EDTA demonstrated a highly effective reduction of intracanal bacterial DNA; GW produced higher reduction and better predictability.

Dendritic cells are an important link between innate and adaptive immune response. The role of dendritic cells in bone homeostasis, however, is not understood. Osteoporosis medications that inhibit osteoclasts have been associated with osteonecrosis, a condition limited to the jawbone, thus called medication-related osteonecrosis of the jaw. We propose that disruption of the local immune response renders the oral microenvironment conducive to osteonecrosis. We tested whether zoledronate (Zol) treatment impaired dendritic cell (DC) functions and increased bacterial load in alveolar bone in vivo and whether DC inhibition alone predisposed the animals to osteonecrosis. We also analyzed the role of Zol in impairment of differentiation and function of migratory and tissue-resident DCs, promoting disruption of T-cell activation in vitro. Results demonstrated a Zol induced impairment in DC functions and an increased bacterial load in the oral cavity. DC-deficient mice were predisposed to osteonecrosis following dental extraction. Zol treatment of DCs in vitro caused an impairment in immune functions including differentiation, maturation, migration, antigen presentation, and T-cell activation. We conclude that the mechanism of Zol-induced osteonecrosis of the jaw involves disruption of DC immune functions required to clear bacterial infection and activate T cell effector response.

OBJECTIVES:
In this study, the effects of ozonetherapy on secondary wound healing were evaluated histologically and immuno-histochemically.

MATERIAL AND METHODS:
Material and Methods: 8 healthy pigs were used in this study. Six wounds with 10 mm in diameter were created through the punch technique on the palatinal gingiva of each pig. Ozone gas was applied on only 3 wounds (test group) and the remaining 3 were left to natural healing (control group). Biopsy samples were taken from one of the wounds in each group on the third day, from another wound of each group on the seventh day, and from another one on the tenth day. Routine histological analysis and immuno-histochemical staining were performed to investigate transforming growth factor-beta (TGF-β) and (VEGF) expressions.

RESULTS:
Results: No statistical difference was found between the test and control groups in terms of collagen fibers, epithelial formation and inflammation scores. A VEGF expression found in the test group was statistically higher than control group samples taken on the 3rd and 7th day. There was no statistical difference between the test and control groups in terms of TGF-β expression on any of the sampling days.

CONCLUSIONS:
Conclusion: The topical application of ozone gas could be effective in the early stages of wound healing by increasing the amount of VEGF expression. Clinical Relevance: Topical application of ozone gas may be effective in the early stages of oral wound healing.

Management of teeth with inflamed pulp has been always a challenge. Revascularization and vital pulp therapy are suggested as procedures for successful treatment of immature molars diagnosed with pulp necrosis and irreversible pulpitis, respectively.

Dental caries, although preventable, remains one of the most prevalent chronic disease worldwide. Most studies focused on the relationship between sugar intake and caries. However, examining multidimensional dietary patterns is becoming increasingly important. Here, we examined the relationship between dietary patterns from ages 6 to 12 months and early childhood caries (ECC) at age 2 to 3-years. Infant dietary data was collected from caregivers and dietary pattern trajectories from 6 to 12 months derived. Oral examinations were carried out by trained calibrated dentists at ages 2 and 3 years. Associations between dietary pattern and ECC were estimated using generalized estimating equation. We found a 3.9 fold lower prevalence of decayed surfaces among children with high Guidelines dietary pattern scores at 6-months (IRR 0.26; CI [0.12-0.53]; p-value < 0.001) and 100% reduction of decayed surfaces with increased intakes of Guidelines dietary pattern foods from 6 to 12-month (IRR 2.4 × 10-4; CI [4.2 × 10-7-0.13]; p-value = 0.01). Suggesting that following the Guideline dietary pattern, which corresponds most closely to current World Health Organization weaning guidelines, at 6 months and an increase in pattern score between 6 and 12 months were protective against ECC development compared to Predominantly breastmilk, Easy-to-prepare foods and Noodles (in soup) and seafood dietary patterns.

Introduction: The etiology of irritable bowel syndrome (IBS) remains elusive even though several genetic and environmental pathogenic factors have been reported. IBS is considered to be a functional disorder without any detectable lesions in the patient’s bowel. However, many studies have demonstrated that a subset of IBS patients have low-grade inflammation and aberrant T-cell activation in their intestinal mucosa. To elucidate the immune mechanism underlying the mucosal inflammation in IBS, we focused on dental metal hypersensitivity, a T cell-mediated, delayed-type allergic reaction that causes oral contact mucositis and systemic cutaneous inflammation.

Methods: We recruited 147 Japanese IBS patients and 22 healthy controls (HCs). The subjects underwent the in vitro lymphocyte stimulation test to quantify their sensitivity to zinc, gold, nickel, and palladium, the metals that have been commonly used in dentistry.

Results: A total of 56.5% of the IBS patients were hypersensitive to at least one metal species, whereas 31.8% of HC were hypersensitive to only a single metal species. The overall incidence of metal hypersensitivity was significantly higher for IBS patients than for HC. Furthermore, a significantly higher proportion of IBS patients were hypersensitive to zinc and/or nickel. The severity of the sensitivity to zinc and nickel was also significantly greater for IBS patients than for HC. There was no significant difference in the sensitization rates and the sensitivity among the IBS subtypes.

Conclusions: This pilot study demonstrates that IBS patients have a significantly higher prevalence of hypersensitivity to zinc and nickel, suggesting the possible involvement of dental metal hypersensitivity in IBS pathogenesis in a subset of patients.

Systemic lupus erythematosus (SLE) is an autoimmune multisystem disease with numerous clinical manifestations. There is no consensus about the ideal oral management for this group of patients to date. This review aimed to describe the broad spectrum of orofacial and clinical manifestations and their therapeutic approaches. Studies concerning orofacial manifestations of SLE and dental treatment modalities were selected by a literature search (1978-2019) using Google Scholar, PubMed/MEDLINE electronic databases. The initial search strategy provided a total of 129 articles, and of these, 30 were included for qualitative synthesis. The reviewed studies revealed that SLE patients are more at risk of compromised oral and dental health exhibiting increased risk of periodontal diseases and temporomandibular joint disorders. The use of systemic drugs especially immunosuppressive and anticoagulants in SLE patients may also influence their oral management. Results emphasize the need to carry out, at an early stage of the disease, an appropriate oral management of these patients to improve oral health-related quality of life and to prevent the need of more invasive therapeutics. A multidisciplinary approach is needed for dental and medical management of such patients.

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of consumer products for their water- and grease-resistant properties, but few studies have explored this exposure route. We used multiple regression to investigate associations between six self-reported behaviors hypothesized to influence PFAS exposure and serum concentrations of six PFAS chemicals in 178 middle-aged women enrolled in the Child Health and Development Studies, about half of whom are African American. Blood samples were collected in 2010-2013, and participants were interviewed about behavior in 2015-2016. Results showed that African American women had lower levels of perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS) compared with non-Hispanic white women. In African Americans, but not others, frequent consumption of prepared food in coated cardboard containers was associated with higher levels of four PFASs. Flossing with Oral-B Glide, having stain-resistant carpet or furniture, and living in a city served by a PFAS-contaminated water supply were also associated with higher levels of some PFASs. Product testing using particle-induced γ-ray emission (PIGE) spectroscopy confirmed that Oral-B Glide and competitor flosses contained detectable fluorine. Despite the delay between blood collection and interview, these results strengthen the evidence for exposure to PFASs from food packaging and implicate exposure from polytetrafluoroethylene (PTFE)-based dental floss for the first time.

Historically, titanium (Ti) has maintained the reputation of being an inert and relatively biocompatible metal, suitable for use in both medical and dental prosthesis. There are many published articles supporting these views, but there is recent scientificevidence that Ti, or its corrosive by-products,
may cause harmful reactions in humans. It is important for all medical and dental professionals to understand the implications, complexities, and all potential pathways of exposure to this metal. These exposures are not only from the environment but also through various commonly used products in medicine that are often completely overlooked. These external (intermittent) and internal (constant) exposures have an impact on whole-body
health. This review examines possible harmful effects, risks, and often ignored potential complications of Ti exposure to human health.

Molecular clocks help organisms to adapt important physiological functions to periodically changing conditions in the environment. These include the adaption of the 24 h sleep-wake rhythm to changes of day and night. The circadian clock is known to act as a key regulator in processes of health and disease in different organs. The knowledge on the circadian clock led to the development of chronopharmacology and chronotherapy. These fields aim to investigate how efficiency of medication and therapies can be improved based on circadian clock mechanisms. In this review we aim to highlight the role of the circadian clock in oral tissues and its potential in the different fields of dentistry including oral and maxillofacial surgery, restorative dentistry, endodontics, periodontics and orthodontics to trigger the evolving field of chronodentistry.