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.

Classic Study
Free-floating bacterial plaque more toxic than attached plaque

Bacterial plaque attached to tooth surfaces is generally accepted as an important factor in periodontal disease, but little is known about the role of bacterial plaque that is free-floating within the pocket. These two forms of bacterial plaque are termed adherent plaque (AP) and loosely adherent plaque (LAP). Researchers at Columbia University in New York designed techniques for the collection of each of these two types of bacterial plaques. Once collected, the volume and the potential for pathological activity for each type could then be determined.

Supragingival samples were collected from the facial surfaces of maxillary incisors. Five subjects refrained from all brushing and interproximal cleaning for two weeks. At that time, a custom mouthguard with windows cut for the facial surfaces of the incisors was inserted, a funnel and test tube were placed below the incisors, and the surfaces were gently rinsed with a stream of water. The water sample with the LAP was collected in the test tube. Supragingival AP was collected with a curet.

Subgingival samples were collected on Mylar strips placed in 7 mm pockets for one week. The strips were carefully removed and gently rinsed with pyrogen-free water for 30 seconds.

AP collected subgingivally after one week was half as much as collected supragingivally after two weeks. In contrast, the LAP mass subgingivally after one week was six times that collected supragingivally after two weeks.

The pathogenic potential of loosely adherent plaque was consistently higher than that of adherent plaque. The figures for loosely adherent plaque were two to 60 times higher for both supragingival and subgingival samples. These findings point to a significant role played by loosely adherent plaque in the destruction of periodontal tissues, especially since these bacteria are in direct contact with sulcular epithelium.

Clinical Implications: Periodontal therapy must focus not only on the root surface, but also on the pocket space where the loosely adherent bacteria can be found. The clinical effectiveness of water irrigation, without removal of adherent plaque, becomes clear with these facts about loosely adherent plaque.

Fine, D., Tabak, L., Oshrain, H., Salkind, A., Siegel, K.: Studies in Plaque Pathogenicity, I. Plaque Collection and Limulus Lysate Screening of Adherent and Loosely Adherent Plaque. J of Perio Research 13: 17, 1978.

Chemicals don’t keep bacteria from adhering to enamel

Plaque control is achieved through mechanical disruption and with chemicals that prevent or reduce bacterial replication. Researchers have been looking for a chemical that would prevent bacteria from adhering to enamel surfaces, but as yet, have found none. Some proved effective in the lab, but were not effective clinically.

Researchers at the University of Bristol in the United Kingdom have found two chemicals that coat the surface of hydroxyapatite and prevent Streptococcus sanguis from adhering. If it works in the lab, will it work in the mouth? To find out, they added each of these two chemicals to a mouthrinse and toothpaste, creating four products to test. A positive control was added with a chlorhexidine rinse and a negative control with water. Standard fluoride toothpaste was also included. Seven products were tested in a group of 18 subjects with a crossover design, allowing each subject to test each product. A washout period of 10 days followed each test. During the washout period, subjects brushed with the traditional fluoride toothpaste.

Subjects reported to the clinic on Mondays for each test. Their teeth were stained with disclosing solution and all plaque was removed. They were then given one of the seven substances to swish for one minute. The rinses were given as prepared. A dose of toothpaste was mixed with water to make a slurry to rinse. Subjects returned to the clinic twice daily to perform the assigned one-minute rinses. On the following Fridays, their teeth were again stained with disclosing solution and plaque scores were recorded.

The traditional toothpaste was slightly more effective in controlling plaque than any of the new formulations or water. Perhaps ingredients in the toothpaste formulation interfered with the test chemicals. However, if the new chemicals were simply ineffective, the plaque scores for the test toothpaste would have been similar to the traditional toothpaste, not higher. It appears the chemicals added to the toothpaste formulation prevented what little effect the toothpaste had by itself.

Clinical Implications: It is unlikely there will soon be a toothpaste or mouthrinse on the market that claims to prevent bacteria from adhering to enamel. However, researchers are still looking for a way to prevent bacteria from adhering to tooth surfaces.

Claydon, N., Addy, M., Newcombe, R., Moran, J.: The Prevention of Plaque Re-Growth by Toothpastes and Solutions Containing Block Copolymers With and Without Polypeptide. J Clin Perio 35: 545-548, 2005.

Improve compliance with patient involvement in the process

Dental disease is preventable with effective daily oral hygiene. It’s simple, really. If people would just brush and floss, disease could be prevented. However, that is not the case. Most people brush for 37 seconds, and only 2-10% of the population flosses daily. Sadly, compliance with daily oral hygiene measures is very poor.

Some research has been done suggesting that psychological variables play a role in compliance. These variables include people identifying with the disease, understanding and discussing disease outcomes with the healthcare professional, consequences and risk factors of non-compliance, and the potential for individual control.

Researchers at the University of Louvain in Belgium compared technique-based oral hygiene instruction to a behavioral approach involving the patient in the discussion, plan, and evaluation of progress. In Belgium, oral hygiene instructions are done by the dentist as the national laws forbid the practice of dental hygiene. Perhaps that is why these researchers decided to evaluate an oral hygiene approach that involves more than simply demonstrating brushing and flossing technique.

The study involved 30 patients from the periodontal clinic, 15 in the traditional group and 15 in the behavioral group. All the subjects were asked to complete a questionnaire assessing their knowledge of periodontal disease and asking if they were willing to change their daily oral hygiene routine. The traditional group received instructions and feedback on technique and a booklet of instructions.

Besides traditional instructions, the test group discussed the questionnaire with the dentist so that they understood all the information. They were asked to fill in a short diary of their compliance indicating which oral hygiene procedures they completed each day. Specific questions in the diary asked how they felt about it, how it felt physically, and, if they didn’t follow the prescribed routine, why they didn’t and what alterations they could make to better follow the plan.

At the end of four weeks, both groups showed significant reductions in plaque levels. The behavioral group was more successful in removing plaque than the traditional group, especially interproximally. Since this was a short-term study, it isn’t known if these results will be sustained long term.

Clinical Implications: Engaging patients in dialog about causes, outcome and treatments of gum disease, asking them to be accountable for their daily oral hygiene routine, setting goals, measuring those goals, and developing alternative strategies when necessary leads to better plaque removal than simply teaching brushing and flossing.

Philippot, P., Lenoir, N., D’Hoore, W., Bercy, P.: Improving Patients’ Compliance With the Treatment of Periodontitis: A Controlled Study of Behavioral Intervention. J Clin Perio 32: 653-659, 2005.

Fifteen-second rinse reaches plaque

Sixty seconds seems to be the recommended rinsing time with many mouthrinse products, especially chlorhexidine-containing solutions. A study in the April 2005 issue of Perio Reports/Hygienetown Magazine found rinsing for just 15 seconds with chlorhexidine controlled three-day plaque re-growth just as well as longer rinsing times. This same research team in the Netherlands have since performed a follow-up study evaluating the spread of mouthrinses in the mouth following various rinsing times.

To measure the spread, they added disclosing solution to the rinse and then measured stained plaque. (Disclosing solution received FDA approval in 1963 for use in staining bacterial plaque deposits on the teeth.)

Thirty periodontally healthy subjects participated, refraining from all oral hygiene for 48 hours prior to the testing. Half the group rinsed with the erythrosine mouthrinse for two 15-second intervals followed by one 30-second interval, adding up to a total of 60 seconds. Between each rinsing interval, plaque scores were recorded. The second group rinsed for three 30-second intervals, with plaque scores recorded between intervals. Both groups received a final disclosing with full strength erythrosine using a cotton swab.

The difference between 15 seconds and 30 seconds was considered statistically significant, but was so small, clinical significance is doubtful. The difference was 0.07 on a plaque score scale of 1 to 5––not different enough to require an additional 15 seconds of rinsing. Although this was not being tested for, researchers were surprised to find more plaque accumulation generally on facial surfaces than lingual surfaces. They speculated that this was probably due to the action of the tongue.

Clinical Implications: Rinsing for 15 seconds will effectively reach nearly all the plaque in the mouth. An additional 15 seconds provides only a very small additional benefit. If you now have your patients use a 60-second pre-treatment rinsing time, consider saving 45 seconds by having them cut down to 15 seconds. Compliance with rinsing may be better with shorter rinsing times.

Paraskevas, S., Danser, M., Timmerman, M., Van der Velden, U., Van der Wejiden, G.: Optimal Rinsing Time for Intra-oral Distribution (spread) of Mouthwashes. J of Clin Perio 32: 665-669, 2005.

Transmucosal lidocaine patch provided effective anesthesia for SRP

The DentiPatch was introduced to the dental hygiene market about 10 years ago. This transmucosal lidocaine patch provides topical anesthesia that penetrates the attached gingiva. These small bandage-sized patches can be used prior to injections to reduce the pain of needle penetration, or they can be used in place of local anesthetic injections for scaling and root planing. Onset of anesthesia occurs within five minutes.

Researchers at the University of California at San Francisco compared the DentiPatch to a placebo patch for controlling pain during quadrant scaling and root planing. Forty subjects with moderate periodontal disease (5 to 8 mm probing depths) participated. Instrumentation was done by quadrants, with visits a week apart. Four hygienists provided all the instrumentation. Neither hygienist nor patient knew if the patches used were test or placebo. Each patient was assigned two test quadrants and two placebo quadrants. Patients were informed that if they wanted rescue anesthesia in the form of an injection, it could be requested at any time.

Patients were asked verbally to describe the pain level experienced, and also asked to fill out a visual analog scale, marking their pain level on a 100 mm line from “no pain” to “extreme pain.” Clinical healing was evaluated one month after the last quadrant was completed.

Seven subjects with a total of nine quadrants requested rescue injections. The majority of subjects were comfortable with both the test and placebo patches. The DentiPatch reduces pain, making the scaling and root planing procedures more comfortable. When asked, 85% of the subjects correctly guessed which patches were test and which were placebo. Nearly 90% of the subjects reported they would request the transmucosal patches over injections in the future.

Clinical Implications: If you want to avoid injections, lidocaine patches provide an alternative for local anesthesia during scaling and root planing.

Perry, D., Gansky, S., Loomer, P.: Effectiveness of a Transmucosal Lidocaine Delivery System for Local Anesthesia During Scaling and Root Planing. J Clin Perio 35: 590-594, 2005.

Depression and focusing on adverse events may influence inflammation

Some research suggests a link between depression and periodontal disease, while other research shows no connection. The most significant problem with this type of research is linking present levels of stress with a history of disease, rather than with current infection. Attachment levels represent disease history and as such, the presence or absence of recent life stresses cannot be linked to attachment loss.

To avoid using historical markers of disease, researchers at the University of Mainz in Germany compared plaque and gingival bleeding to stressful events, depression, and perception of stress. The test group consisted of 140 patients in a private dental practice. Each subject was examined for interproximal plaque and gingival bleeding. Also recorded were missing teeth and filled teeth. Subjects were asked to complete several evaluations measuring life changes in the past six months, the impact of those events, depression, and potentially psychosomatic symptoms. Dental history and last dental visit were also recorded.

Plaque levels did not relate to any of the stress or depression measures. This may be due to the fact that people tend to clean their teeth a bit better than usual before a dental appointment. Sulcular bleeding was linked to depression, worry, and the number of psychosomatic symptoms reported. People who reported a tendency to cancel or avoid dental visits had higher levels of disease and more missing teeth.

Clinical Implications: Discussing stress reduction techniques may become part of the hygienist’s interaction with patients along with oral hygiene instructions and emphasizing the importance of regular dental hygiene visits.

Klages, U., Weber, A., Wehrbein, H.: Approximal Plaque and Gingival Sulcus Bleeding in Routine Dental Care Patients: Relations to Life Stress, Somatization and Depression. J Clin Perio 32: 575-582, 2005.