Category: Dentistry

Bacteria in Severe Oral Infections Linked to Other Diseases

Dentist checking teeth
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To date, there has been little research into identifying the bacteria found in severe oral infections, despite long-suspected links to other diseases. Now, a study from Karolinska Institutet has characterised the microbial composition of these, with many known to be linked to other disease. The study is published in Microbiology Spectrum.

There is growing evidence linking oral health and common diseases, such as cancer, cardiovascular disease, diabetes and Alzheimer’s disease. However, there have been few longitudinal studies identifying which bacteria occur in infected oral- and maxillofacial regions.

Researchers at Karolinska Institutet have now analysed samples collected between 2010 and 2020 at the Karolinska University Hospital in Sweden from patients with severe oral infections and produced a list of the most common bacteria.

“We’re reporting here, for the first time, the microbial composition of bacterial infections from samples collected over a ten-year period in Stockholm County,” says Professor Margaret Sällberg Chen of the Department of Dental Medicine. “The results show that several bacterial infections with link to systemic diseases are constantly present and some have even increased over the past decade in Stockholm.”

A role in other diseases

The study shows that the most common bacterial phyla amongst the samples were Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria, while the most common genera were Streptococcus spp, Prevotella spp, and Staphylococcus spp.

“Our results provide new insight into the diversity and prevalence of harmful microbes in oral infections,” says Professor Sällberg Chen. “The finding isn’t only of importance to dental medicine, it also helps us understand the role of dental infection in patients with underlying diseases. If a certain bacterium infects and causes damage in the mouth, it’s very likely that it can be harmful to tissues elsewhere in the body as the infection spreads.”

The research group has previously shown that the occurrence of oral bacteria in the pancreas reflects the severity of pancreatic tumours.

Improve diagnostics and therapy

The study was conducted using 1014 samples from as many patients, of whom 469 were women and 545 men, and a mass-spectrometric method called MALDI-TOF that rapidly identifies individual living bacteria in a sample, but that is rarely used in dental care.

“Our study was a single centre epidemiology study and to ensure the validity of the results we need to make more and larger studies,” says adjunct Professor Volkan Özenci at the Department of Laboratory Medicine. “We now hope that dentists will collaborate with clinical microbiology laboratories more to gain a better understanding of the bacteria that cause dental infections, to improve diagnostics and therapeutic management of oral infections.”

The study is part of Khaled Al-Manei’s doctoral thesis, the next step of which is a similar epidemiological study of fungal infections in the mouth that aims to identify new fungi and microbes and understand what causes their possible malignancy. 

Source: Karolinska Institutet

Vaping Device Use Tied to Increased Risk of Developing Cavities

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Research published in The Journal of the American Dental Association found patients who said they used vaping devices were more likely to have a higher risk of developing cavities. The findings of this study on the association between vaping and risk of caries serve as an alert that this once seemingly harmless habit may be very detrimental, says Karina Irusa, assistant professor of comprehensive care at Tuftst University and lead author on the paper.

Over the last few years, public awareness has increased about the dangers of vaping to systemic health, particularly after the use of vaping devices was tied to lung disease. Some dental research has shown ties between e-cigarette use and increased markers for gum disease, and, separately, damage to the tooth’s enamel, its outer shell. But relatively little emphasis has been placed on the intersection between e-cigarette use and oral health, even by dentists, says Irusa.

Irusa says that the finding may be just a hint of the damage vaping causes to the mouth. “The extent of the effects on dental health, specifically on dental decay, are still relatively unknown,” she says. “At this point, I’m just trying to raise awareness,” among both dentists and patients.

This study, Irusa says, is the first known specifically to investigate the association of vaping and e-cigarettes with the increased risk for getting cavities. She and her colleagues analysed data from more than 13 000 patients older than 16 who were treated at Tufts dental clinics from 2019–2022.

Irusa found a significant difference in dental caries risk levels between the e-cigarette/vaping group and the control group. Some 79% of the vaping patients were categorised as having high-caries risk, compared to just about 60% of the control group. The vaping patients were not asked whether they used devices that contained nicotine or THC, although nicotine is more common.

“It’s important to understand this is preliminary data,” Irusa says. “This is not 100% conclusive, but people do need to be aware of what we’re seeing.” Further studies need to be done, and Irusa wants to take a closer look at how vaping affects the microbiology of saliva.

One reason why e-cigarette use could contribute to a high risk of cavities is the sugary content and viscosity of vaping liquid, which, when aerosolised and then inhaled through the mouth, sticks to the teeth. (A 2018 study published in the journal PLOS One likened the properties of sweet-flavoured e-cigarettes to gummy candies and acidic drinks.) Vaping aerosols have been shown to change the oral microbiome making it more hospitable to decay-causing bacteria. It’s also been observed that vaping seems to encourage decay in areas where it usually doesn’t occur – such as the bottom edges of front teeth. “It takes an aesthetic toll,” Irusa says.

The Tufts researchers recommend that dentists should routinely ask about e-cigarette use as part of a patient’s medical history, including paediatric dentists who see adolescents. According to the FDA/CDC, 7.6% of middle- and high-school students said they used e-cigarettes in 2021.

The researchers also suggest patients who use e-cigarettes should be considered for a “more rigorous caries management protocol,” which could include prescription-strength fluoride toothpaste and fluoride rinse, in-office fluoride applications, and checkups more often than twice a year.

“It takes a lot of investment of time and money to manage dental caries, depending on how bad it gets,” Irusa says. “Once you’ve started the habit, even if you get fillings, as long as you continue, you’re still at risk of secondary caries. It’s a vicious cycle that will not stop.”

Source: Tufts University

Study Gives Water Fluoridation a Green Thumbs Up

Teeth and toothbrush
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For the first time, researchers have demonstrated the low environmental footprint of water fluoridation compared to other preventive measures for tooth decay while still retaining effectiveness. The study is published in the British Dental Journal.

Water fluoridation is regarded as one of the most significant public health interventions of the twentieth century. But as the climate crisis worsens, the contribution of healthcare and the prevention of disease to the crisis must be considered.

Influenced by this urgency, Trinity College Dublin researchers collaborating with University College London quantified the environmental impact of water fluoridation for an individual five year-old child over a one-year period and compared this to the traditional use of fluoride varnish and toothbrushing programmes, which take place in selected schools across the UK, and internationally.

Over 35% of the world’s population has access to water fluoridation, with studies showing significant reductions in dental caries. Whilst data on the clinical effectiveness and cost analysis of water fluoridation are available, there has been no data regarding its environmental impact up to now.

To quantify this impact, the research team performed a Life Cycle Assessment by carefully measuring the combined travel, the weight and amounts of all products and the processes involved in all three preventive programmes (toothbrushing, fluoride varnish programmes and water fluoridation). Data was inputted into specialised environmental software and the team used the Ecoinvent database, enabling them to calculate environmental outputs, including the carbon footprint, the amount of water used for each product and the amount of land use.

The results of the study, led by Brett Duane, Associate Professor in Dental Public Health at Trinity College, concluded that water fluoridation had the lowest environmental impact in all categories studied, and had the lowest disability-adjusted life years impact when compared to all other community-level caries prevention programmes. The study also found that water fluoridation gives the greatest return on investment.

Considering the balance between clinical effectiveness, cost effectiveness and environmental sustainability, researchers believe that water fluoridation should be the preventive intervention of choice.

This research strengthens the case internationally for water fluoridation programmes to reduce dental decay, especially in the most vulnerable populations.

Assoc Prof Duane said: “As the climate crisis starts to worsen, we need to find ways of preventing disease to reduce the environmental impact of our health systems. This research clearly demonstrates the low carbon impact of water fluoridation as an effective prevention tool.”

Source: Trinity College Dublin

Nocturnal Teeth Grinding is Damaging for Temporomandibular Joints

Woman showing her teeth
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Sleep bruxism, nocturnal teeth grinding and clenching of the upper and lower jaw, can have a number of health impacts. A new study published in the Journal of Advanced Research found that certain tooth shapes and tooth locations could well lead to temporomandibular joint problems as a result of bruxism.

About 15% of the population grind their teeth while they are asleep, a condition which is more common among younger people. The\ pressure exerted on tooth surfaces and on the jaws can be immense and is thought to cause various dental health problems. It can also result in pain in the jaw muscles and headaches. Specific combinations of tooth shape and tooth location during grinding are theorised to have an influence on the mechanical load on the temporomandibular joint and can thus be considered a risk factor for temporomandibular joint (TMJ) disorders.

To investigate whether sleep bruxism has a negative impact on the TMJ structures, researchers used a state-of-the-art computer model of the masticatory region, which includes bone, cartilage and muscular structures. Such computer models can be used to investigate research questions when direct studies on patients are not feasible on ethical grounds.

The study investigated two factors thought to be involved: tooth shape and location, The study simulated the effects of lateral grinding on the first molar and on the canine with six different wear facet inclinations, resulting in a total of twelve simulated scenarios.

“Our results show that both the inclination and location of the wear facets have an influence on the strength of the mechanical load on the temporomandibular joint,” explained study leader Benedikt Sagl. “However, it would appear that the decisive factor is the steepness of the grinding facet. The flatter the tooth, the higher the loading on the joint and therefore the higher the risk of a TMJ disorder.” Conversely, if the dental cusps involved in bruxism have a steeper angle of inclination, the calculated joint loading was lower, even with the same “grinding force” (bruxing force). Further research, coupled with clinical investigations, will seek to establish whether this finding can be incorporated into the development of therapeutic interventions for sleep bruxism.

Source: Medical University of Vienna

Obesity Found to Fuel Periodontal Disease

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Chronic inflammation resulting from obesity may trigger osteoclast production and bone tissue breakdown, including the alveolar bone that holds teeth in place, according to a new animal model study.

The study, reported in the Journal of Dental Research, found that excessive inflammation caused by obesity raises the number of myeloid-derived suppressor cells (MDSC), a group of immune cells that increase during illness to regulate immune function. MDSCs, which originate in the bone marrow, develop into a range of different cell types, including osteoclasts.

Bone loss is a major symptom of periodontal disease which may ultimately lead to tooth loss. Periodontal disease affects more than 47% of adults 30 years and older, according to the Centers for Disease Control and Prevention.

“Although there is a clear relationship between the degree of obesity and periodontal disease, the mechanisms that underpin the links between these conditions were not completely understood,” said Keith Kirkwood, DDS, PhD, professor of oral biology in the UB School of Dental Medicine.

“This research promotes the concept that MDSC expansion during obesity to become osteoclasts during periodontitis is tied to increased alveolar bone destruction. Taken together, this data supports the view that obesity raises the risk of periodontal bone loss,” said Kyuhwan Kwack, PhD, postdoctoral associate in the UB Department of Oral Biology.

In the study, two groups of mice were fed different diets over the course of 16 weeks: one group a low-fat diet that derived 10% of energy from fat, the other group a high-fat diet getting 45% of energy from fat.

The high-fat diet group developed obesity, had more inflammation and a greater increase of MDSCs in the bone marrow and spleen compared to the low-fat diet group. The high-fat diet group also developed a significantly larger number of osteoclasts and lost more alveolar bone, which holds teeth in place.

Additionally, in the group fed a high-fat diet, the expression was significantly elevated for 27 genes tied to osteoclast formation.
The findings may help reveal the mechanisms behind other chronic inflammatory, bone-related diseases that develop concurrently with obesity, such as arthritis and osteoporosis, Prof Kirkwood said.

Source: University at Buffalo

Root Canals Still Preferred Over Tooth Extraction

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Few patients regret having a severely damaged tooth saved by a root canal filling, with a PhD thesis finding that 87% would choose the same treatment again if needed, despite the pain and discomfort.

Root fillings are often required because the soft tissue inside the tooth, the dental pulp, is inflamed or infected. The root canal treatment is carried out in stages, on several occasions, where the dentine and other parts are removed and the root canals are finally filled with a combination of a natural, rubberlike material (gutta-percha) and a cement.

Root canal treatment is still a common and necessary measure despite good oral health. In Sweden, as in most countries, most root canal treatments are performed by general dental practitioners in the public or private sector.

In dentist Emma Wigsten of the Institute of Odontology’s thesis, several studies analysed data on a patient group of 243. All of them had started root canal treatment at one of the 20 public dental clinics in the region, and the patients were then followed up for one to three years.

Most of the root canal treatments were prompted by toothache in teeth with caries and large restorations, which culminated in root fillings within a year. Molars were an exception: only just over half of the root fillings met their purpose and, as a result, many molars had to be extracted.

“It seems harder to get a good result in treating the molars, despite time and resources invested. Root canal treatment is complicated: You’re working inside the tooth where you can’t see anything, and the further back you go in the mouth, the more difficult it becomes,” Wigsten said.

“Root canal treatments of molars involve significantly bigger challenges than other tooth groups. So it may be important to investigate whether root canal treatments of molars should be performed to a greater extent by dentists specialising in root canal treatment.”

During the follow-up period of up to three years, half of the patients stated that they had mild pain or discomfort from their root-filled tooth. Nevertheless, most (87%) were satisfied and did not regret opting for root canal treatment over a tooth extraction.

Another component study, at six public dental clinics in Region Västra Götaland, covered 85 patients in whom either root canal treatment was initiated or a tooth was extracted. An improved health-related quality of life was observed in the patients who started root canal treatment, but not in those who underwent a tooth extraction.

“The studies show that the patients’ quality of life benefited from root canal treatment. On the other hand, it’s unclear whether the treatment is cost-effective compared with tooth removal, especially where molars are concerned,” Wigsten concluded.

Source: University of Gothenburg