Perio Reports

Perio Reports provides easy to read research summaries on topics of specific interest to clinicians. Perio Reports research summaries will be included each month to keep you on the cutting edge of dental hygiene science.

Perio infection can increase cytokines in amniotic fluid

Studies both support and refute the claim that periodontal disease predisposes women to preterm delivery. Dental school researchers at the University of Vienna, Austria wanted to know how periodontal infection could trigger preterm delivery. To find the answer, they worked with a gynecologist working in the medical school at the same university who was performing amniocentesis on women with high-risk pregnancies. The women agreed to have an additional 2 ml of fluid removed for analysis of bacteria and cytokines associated with periodontal infection and to undergo a complete periodontal examination. These procedures were done between weeks 15 and 20 of the pregnancies in a total of 36 women. Six of these women did deliver preterm, despite no apparent medical cause revealed through amniocentesis.

Subgingival plaque samples revealed both bacterial type and quantity. All the women who delivered preterm had signs of periodontal disease, yet not all the women with periodontal disease delivered preterm.

Smoking was not considered a risk factor, as only one woman smoked, and she had no signs of periodontitis and delivered full term.

No bacteria were found in the amniotic fluid. The high molecular weight of bacteria prevents their passage through the placental barrier. However, proteins and cytokines are of a lower molecular weight and were found in the amniotic fluid. Prostaglandin E₂ (PGE₂) was 1.8 times higher and IL-6 was 1.5 times higher in amniotic fluid of subjects with periodontitis. Both of these cytokines can induce membrane rupture and begin the birth process. These cytokines were elevated in the women who delivered preterm. Five of the six women who delivered preterm also had high counts of subgingival bacteria, compared to four out of 30 women who delivered full term.

The upregulation of PGE₂ and IL-6 associated with periodontal infection was evident in the 15-20 week period of the pregnancies of those who later delivered preterm.

Clinical Implications: Periodontal infection in a pregnant woman can trigger a host response in the amniotic fluid which can potentially lead to preterm delivery.

Dörtbudak, O., Eberhardt, R., Ulm, M., Persson, G.: Periodontitis, A Marker of Risk in Pregnancy for Preterm Birth. J Clin Perio 32: 45-52, 2005.

British researchers find no link between perio disease and preterm birth

A study conducted at Kings College in London, England included 154 subjects, 93 delivered before 37 weeks and 61 delivered full-term babies. The women were recruited within five days postpartum. Periodontal examinations were done in the hospital at the mother’s bedside using a portable light, mirror and probe. Probings were done on facial and mesial-facial sites on upper teeth as well as lingual and mesial-lingual sites on lower teeth. Partial probings can underestimate the level of disease, but researchers wanted to keep the examination time short and the discomfort to a minimum. The partial probing technique they selected is considered more reflective of disease than other screening techniques, but this may still have introduced bias into the study design.

No differences were observed between the full-term and pre-term groups for probing depths, plaque, bleeding or attachment levels. However, those delivering preterm included 39% smokers, compared to the UK national average among pregnant women of 27% smokers. The pre-term group also reported a higher incidence of antibiotic usage, especially in the time right before delivery.

Conclusions reached in this study differ from several previously published reports. Study population differences may explain this. The Kings College study population had much less periodontal disease than reported in other studies. For example, the average probing depth in this study was 2.23 mm, compared to an average probing depth of 3.17 mm reported in the University of North Carolina study for those delivering pre-term and 2.87 mm for those with the healthiest periodontium.

Clinical Implications: Preterm delivery and low birth weight are associated with factors other than periodontal disease, such as smoking prior to and during the pregnancy and antibiotic usage prior to delivery.

Moore, S., Randhawa, M., Ide, M.: A Case-Control Study to Investigate an Association Between Adverse Pregnancy Outcome and Periodontal Disease. J Clin Perio 32: 1-5, 2005

Dietary Omega-3 fatty acids reduce cytokines

Periodontal destruction is caused indirectly by bacteria and more directly by complex immune responses to bacteria and their toxins. Lipopolysaccharide (LPS), found in cell walls of Gram-negative bacteria, triggers the release of arachidonic acid metabolites, cytokines and enzymes that destroy bone and connective tissue. Arachidonic acid metabolites are released along two pathways COX (cyclooxygenase) and LOX (lipoxygenase). COX-2 inhibitors are drugs that block the COX pathway, reducing the production of arachidonic acid. COX2 inhibitors do not block the LOX pathway. Omega-3 fatty acids compete with arachidonic acid along both the COX and LOX pathways. Omega-3 fatty acids have already been shown to reduce cytokines associated with gingivitis. Researchers at Ege University in Izmir, Turkey designed a laboratory study with rats to determine if omega-3 fatty acids would provide the same benefits in treating periodontitis.

Following an established experimental periodontitis model, bacterial toxins were injected into interdental papilla to induce disease. Toxin injections were repeated three times, every other day over a six-day period. As a control, one group received saline instead of toxin injections. The control group was tube fed saline on a daily basis. The first experimental periodontitis group was tube fed saline. The second experimental periodontitis group was tube fed omega-3 fatty acids on a daily basis. To test preventive capabilities of omega-3 fatty acid as well as therapeutic, the third experimental periodontitis group began receiving omega-3 fatty acids 15 days before the endotoxin injections and continued receiving omega-3 fatty acids for the next 15 days of the study.

The omega-3 fatty acids effectively controlled levels of arachidonic acid and other cytokines in the periodontal tissues. Omega-3 fatty acids seem to inhibit arachidonic acid along both the COX and LOX pathways, something COX2 inhibitor drugs cannot do.

Clinical Implications: Don’t start recommending Omega-3 fatty acid supplementation to treat periodontal disease just yet. More research is needed before Omega 3 fatty acids become part of the treatment and prevention of periodontal disease. However, a diet rich in Omega 3 fatty acid containing foods does make sense for good general health.

Vardar, S., Buduneli, E., Tüko glu, O., Berdeli, A., Baylas, H., Baskesen, A., Atilla, G.: Therapeutic Versus Prophylactic Plus Therapeutic Administration of Omega-3 Fatty Acid on Endotoxin-Induced Periodontitis in Rats. J Perio 75: 1640-1646, 2004.

Treating periodontal disease improves blood vessel function

Several researchers suggest a link between periodontal disease and heart disease. Localized infections may cause chronic systemic inflammation resulting in changes in blood vessel walls, thus explaining the link between periodontal disease and heart disease.

Vascular endothelium or the cells lining blood vessels synthesize substances that regulate many aspects of vessels, including vascular tone, permeability, cell growth, vasodilation and vasoconstriction. Endothelial dysfunction is the inability of blood vessels to dilate and is a precursor of atherosclerosis. It can be measured in the brachial artery of the arm at the antecubital fossa (inside the elbow) with ultrasound.

Researchers at Istanbul University in Turkey wanted to know if endothelial dysfunction was associated with periodontal disease and if periodontal treatment would reverse dysfunction. They compared 26 periodontally healthy control patients with 28 periodontal patients. None of the subjects had any signs or history of heart disease based on interviews and extensive testing. Endothelial dysfunction was measured on the arm after inflating a blood pressure cuff to 200mm/Hg for five minutes. This test demonstrates flow-mediated vasodilation of the endothelial cells. A second test involved placing nitroglycerine under the tongue and monitoring vessel changes.

Baseline endothelial scans showed normal function for controls and inhibited function for those with periodontal infections. The test group then received treatment including oral hygiene instructions and five hours of subgingival instrumentation over several visits. The control group with healthy periodontal tissues received only oral hygiene instructions. After six weeks, the blood vessel scans were repeated. This time, both groups had similar readings. The control group showed no change, and the group that received periodontal treatment showed significant improvement.

Clinical Implications: This study suggests that non-surgical therapy may be important in preventing vascular complications triggered by chronic periodontal infections. More and larger studies are needed to confirm these preliminary findings.

Mercanoglu, F., Oflaz, H., Öz, O., Gökbuget, A., Genchellac, H., Sezer, M., Nisanci, Y., Umman, S.: Endothelial Dysfunction in Patients With Chronic Periodontitis and Its Improvement After Initial Periodontal Therapy. J Perio 75: 1694-1700, 2004.

Daily Fosamax® shows improved alveolar bone density

The onset of menopause usually occurs between the ages of 48 and 51 years. Ovarian function diminishes and estrogen levels drop, often leading to many physical and oral manifestations. Some women experience xerostomia, taste alterations, burning mouth, caries, periodontal disease and osteoporosis of the alveolar bone. Fosamax (alendronate) is a bisphosphonate drug that inhibits osteoclastic activity at sites of bone resorption and is therefore recommended for those at risk of osteoporosis.

Dental researchers at the University of Guanajuato in Leon, Mexico have measured the effects of Fosamax in patients with type 2 diabetes and found definite evidence of reduced osteoclastic activity. In this study, the same research team compared the effects of daily Fosamax and a placebo in post-menopausal women undergoing non-surgical periodontal therapy and oral hygiene instructions. The two groups’ 20 subjects were further delineated as obese or not. From the osteoporosis perspective, body fat can protect against bone loss by producing and storing estrogen. Conversely, obesity is considered a risk factor for periodontal disease. Because of this information, the researchers evaluated the data, based on test and control groups and also for the subgroups, obese or not.

Women in the test group took a 10 mg daily dose of Fosamax and the controls took a look-alike placebo. Patients received four sessions of subgingival instrumentation and follow-up visits every two weeks for six months to measure plaque and bleeding, and to review flossing. Digital radiographs were taken at baseline and six months. Full-mouth radiographs were used to evaluate alveolar bone levels and a standardized film of the foot was used to evaluate changes to the calcaneus bone.

Both test and control groups showed improved clinical health as a result of mechanical therapy and improved oral hygiene. Differences were evident between the groups, although slight. The Fosamax group did show evidence of an increase in bone density, while the control group showed loss of bone density. The Fosamax group also showed a greater reduction in systemic markers of bone breakdown compared to the control group. The subgroup of obese women fared better than the non-obese women for measures of improved bone density.

Clinical Implications: Evaluate patients currently taking Fosamax to see if periodontal bone health is improving more than normally expected with traditional mechanical therapy and oral hygiene instructions. Larger, long-term studies are needed before Fosamax is recommended as an adjunct to non-surgical periodontal therapy.

Rocha, M., Malacara, J., Sánchez-Marin, F., Vazquez de la Torre, C., Fajardo, M.: Effect of Alendronate on Periodontal Disease in Postmenopausal Women: A Randomized Placebo-Controlled Trial . J Clin Perio 75: 1579-1585, 2004