Perio Reports

Photodynamic therapy treats periodontal disease

Photodynamic therapy (Periowave from Ondine Biopharma) involves delivering a 0.01% methylene blue-light-activated substance to the subgingival area and then exposing it to a non-thermal diode laser that activates the substance and kills periodontal pathogens. Researchers at the Wenzhou Medical College in China tested this technology on periodontal patients following scaling and root planing (SRP). Test Group One received a single Periowave treatment after SRP. Test Group Two received the Periowave treatment after SRP and again at week six. Test Group Three, the control group, received SRP only. Clinical indices were measured at baseline, and again at six and 12 weeks.

Nearly 2,000 sites were treated. Both test and control groups showed healing. Those receiving two photodynamic treatments showed an additional increase in clinical attachment of 0.44 mm. Men receiving two Periowave treatments showed a gain in clinical attachment of 2.06 mm compared to 1.61 mm for women who received two treatments.

Two Periowave treatments resulted in the resolution of more pockets than one treatment or no treatments. Fifty-six percent of probing depths 5 mm or greater were reduced to 3 mm compared to 37% for both the one treatment group and the control group. Eighty-five percent of 4 mm pockets were reduced to 3 mm in the Periowave group compared to 67% in the one treatment group and 63% in the control group.

Clinical Implications: The Ondine Periowave system is an effective method for disinfecting periodontal pockets. It is now available in Canada and may soon be available in the United States.

Wang, Y., Lin, Z., Zhang, X., Ding, X., Chen, H., Zhu, X., Wang, J., Lee, S., Kim, J., Li, Y.: Comparative Efficacy of Photodynamic Periodontal Treatment Between Genders, Clinical Efficacy of a New Photodynamic Treatment for Periodontal Diseases, Recovery Rates of Periodontal Pockets Treated Photodynamic Disinfection. J of Dent Research, Abstract Numbers: 1197,1196, and 1199, 2007.

Periowave kills 99% of subgingival bacteria

Periowave from Ondine Biopharma is a photodynamic therapy system. This approach uses a non-thermal diode laser to activate a 0.01% methylene blue substance placed into periodontal pockets. The dye has an affinity for bacteria and is activated by the laser light, thus killing the periodontal pathogens.

In a laboratory study done by Ondine Bio-pharma, the Periowave system was tested on both planktonic and biofilm bacteria in culture. By testing several non-thermal producing diode laser settings, it was found that a laser setting of six Joules achieved a 99% kill rate for three bacterial pathogens: P. gingivalis, F. nucleatum, and A. actinomycetemocomitans in both biofilm and planktonic cultures. Reducing the energy dose resulted in a dose-dependent killing effect on the bacteria. The lower the energy setting, the fewer bacteria were killed. Changes in sample temperature did not exceed 3-degrees Celsius during these experiments.

Clinical Implications: The Periowave photodynamic therapy system provides a new option for eradicating periodontal pathogens. Clinical studies are now needed to confirm this kill rate in the mouth.

Street, C., Pedigo, L., Loebel, N.: In Vitro Photodynamic Eradication of Periopathogens Using the Periowave System. J Dent Research Abstract Number 3015, 2007.

Povidone-iodine effective pretreatment rinse

The American Heart Association recommends systemic antibiotics prior to dental treatment for those at risk of bacterial endocarditis. Antimicrobial pretreatment rinsing is also recommended over subgingival irrigation, as irrigation itself may cause a bacteremia.

Researchers at Westmead Hospital in Australia compared two consecutive one-minute pretreatment rinses with either 7.5% povidone-iodine (PI) or sterile saline (SS). Statistical calculations determined that the test and control groups should each include 30 subjects with plaque-induced gingivitis. Blood samples were taken immediately after rinsing. Samples were taken again, 30 seconds after the start of ultrasonic scaling and again after completing two-minutes of scaling in the lower left quadrant.

Bacteremia was identified for one person in the test group and four people in the control group at 30 seconds. At two- minutes, nine in the control group and two in the test group exhibited bacteremia. This translates to a bacteremia incidence of 33% in the SS rinse group and 10% in the PI group. Statistical analysis showed that rinsing with PI was approximately 80% more effective than rinsing with SS in reducing the incidence of bacteremia.

Twenty-four oral bacteria were identified in the SS group and only three in the PI group. Viridans streptococci are common pathogens found in cases of infective endocarditis. These pathogens comprised 11 of the 24 isolates found in the SS group. None were found in the PI group.

Clinical Implications: A two-minute pretreatment rinse with 7.5% povidone-iodine will significantly reduce the incidence of bacteremia and kill Viridans streptococci when using an ultrasonic scaler in the treatment of patients with plaque induced gingivitis.

Cherry, M., Daly, C., Mitchell, D., Highfield, J.: Effect of Rinsing With Povidone-Iodine on Bacteraemia Due to Scaling: A Randomized-Controlled Trial. J Clin Perio 34: 148-155, 2007.

Brush head still effective after three months

Researchers and product companies suggest replacing brushes every two to three months or when the bristles are splayed.

Researchers at the University of Sydney in Australia compared new and used power brush heads for plaque removal. A total of 35 subjects were each given a Braun Oral-B D9 oscillating power toothbrush and instructed to use only this power toothbrush.

After three months, brush heads were returned to the clinic to be photographed, analyzed and kept for plaque removal testing. Subjects returned for two plaque-removal tests, two weeks apart and refrained from all oral hygiene for 48 hours before these appointments. The teeth were disclosed, plaque levels recorded, and with the flip of a coin either the new brush head or their three-month old brush head was used for two minutes without a mirror. The next visit followed the same protocol with the other brush head.

Splayed bristles were evident by an increase in the total area the brush head covered. Images were evaluated and brush wear resulting in a larger circle for the bristles was observed, ranging from 0% to 135%.

No difference was found for plaque removal when comparing new and used brush heads. Brush heads with the most wear were just as effective as new brushes for plaque removal. Plaque removal on facial and lingual surfaces was 38% with new brush heads and 37% with worn brush heads. Approximal plaque removal was 31% for both brush head groups.

Clinical Implications: This challenges recommendations to replace brush heads every three months for better plaque removal. It seems the brushing technique needs changing rather than the brush head.

Hogan, L., Daly, C., Curtis, B.: Comparison of New and 3-Month-Old Brush Head in the Removal of Plaque Using a Powered Toothbrush. J Clin Perio 34: 130-136, 2007

Perio therapy linked to inflammatory response

Periodontal disease is a chronic low-grade infection with inflammation. Subgingival instrumentation can cause a bacteremia and trigger changes in the body related to inflammation. Some of these changes are detected in blood samples and measured in changes associated with endothelial cells, which are specialized epithelial cells lining blood vessels. Endothelial cells are involved in vasodilation and constriction (blood pressure), blood clotting, atherosclerosis, inflamation, edema, etc.

Researchers at the Eastman Dental Institute in London, England, evaluated changes following subgingival periodontal therapy. Subjects all showed signs of severe periodontal disease.

A total of 55 patients participated in this 30-day study. Subgingival instrumentation was carried out under local anesthesia and was completed within six hours. Blood samples were collected before treatment and again one, seven and 30 days after treatment. Several blood tests were completed to determine the presence of biomarkers of inflammation and clotting factors.

Periodontal therapy did increase levels of several cytokines in the week following therapy. This is the first study to demonstrate the influence of periodontal therapy on systemic inflammatory response and biomarkers associated with endothelial cells. As a preliminary study, the authors pointed out that a larger study is needed with measurements taken earlier than one day following treatment to determine exactly when the peak in inflammatory biomarkers occurs.

Clinical Implications: These findings add to our understanding of the relationship between periodontal treatment and the inflammatory process as measured by changes in the blood.

D’Aiuto F., Parkar M, Tonetti M.: Acute Effects Of Periodontal Therapy on Bio-Markers of Vascular Health. J Clin Perio 34: 124–129. 2007.

The previous authors and a larger research team treated 108 patients with advanced disease and evaluated blood samples for inflammatory biomarkers and clotting factors, as in the previous study. They also evaluated dilation of the brachial artery as related to blood flow. Blood samples were taken before treatment and one, seven, 30, 60 and 180 days after treatment. All patients had severe periodontitis, defined as probing depths greater than 6 mm and bone loss greater than 30% affecting 50% or more of the teeth. Subgingival instrumentation was completed for 55 patients and 53 patients comprised the control group receiving only supragingival treatment. Both groups received oral hygiene instructions. Arestin local delivery antibiotic was placed in the pockets of those receiving subgingival instrumentation.

Intensive periodontal therapy resulted in reduced probing depths, reduced bleeding and less plaque than supragingival therapy.

In the intensive group, a transient acute inflammatory response and impairment of the endothelial cells occurred. CRP levels were elevated on day one and dropped back to baseline levels on day seven. White blood cell counts spiked on day one and dropped below baseline levels and below the control group on day seven.

Ultrasound imaging was used on the brachial artery prior to and during after inflating a blood pressure cuff to 250 mm of HG for five minutes. Doppler flow measurements were also taken. After intensive periodontal treatment, blood flow was lower than the control group, but by two months it increased to higher levels than the control group. At six months, better endothelial function was measured in the test group.

Clinical Implications: This larger study demonstrates a relationship between periodontal therapy and the endothelial cells of the blood vessels.

Tonetti, M., D’Aiuto, F., Nibali, L., Donald, A., Storry, C., Parkar, M., Suvan, J., Hingorani, A., Vallance, P., Deanfield, J.: Treatment of Periodontitis and Endothelial Function. NEJM 356: 912-920, 2007.