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.

Plaque removal enhances remineralization

White spot lesions can be remineralized and reversed, but the exact protocol for accomplishing this with various fluoride products has not yet been established. For this reason, researchers in Brazil compared white spot lesions in three groups of 7–12-year-old children who had high caries rate and poor oral hygiene. They wanted to determine the effect of weekly applications of fluoride gel on white-spot lesion activity. Two groups received weekly supervised toothbrushing, followed by a one-minute application of either 1.23% acidulated phosphate fluoride (APF) gel or a placebo gel. The control group received no treatment during the eight-week test period. Final evaluation was done at three months on a total of 258 children.

The supervised toothbrushing proved to be the key to reversing the white spot lesions. The study was short and the authors wondered if better results would have been seen had the fluoride been used over a longer time period. The two toothbrushing groups ended the study with 42% and 43% baseline lesions still active compared to the control group with 57% of baseline lesions still active. Plaque levels were significantly lower for those receiving supervised brushing, compared to the control group, which showed only a slight improvement in plaque levels.

Clinical Implications: “A clean tooth will not decay,” was said many years ago by Dr. Bass and is still true today. Without plaque, the caries process cannot progress. Fluoride may provide additional benefit, but keeping the tooth clean allows areas of demineralization to remineralize naturally with minerals from the saliva.

Ferreira, M., Latorre, M., Rodrigues, C., Lima, K.: Effect of Regular Fluoride Gel Applications on Incipient Carious Lesions. Oral Health Prev Dent 3: 141-149, 2005.

Quality of oral hygiene more important than frequency

Researchers at the Georg-August University in Göttingen, Germany reviewed the research to determine what evidence exists for brushing before or after eating and how frequently the teeth should be brushed. Researchers agree that bacterial biofilm is responsible for both caries and periodontal disease. Certain risk factors also play a part, for example: diabetes, tobacco and genetics. However, it is the effective, daily removal of bacterial biofilm from all surfaces of the teeth that will prevent disease.

Brushing longer than 60 seconds has shown little advantage, presumably because brushing was confined to the same surfaces, continually missing other areas. In one study, increasing the brushing from one minute to four minutes resulted in more plaque removal; however, posterior and lingual surfaces still had high plaque levels compared to anterior teeth and buccal surfaces. A systematic review of the research revealed that education and instruction has only a slight and temporary influence on plaque levels.

Traditionally, toothbrushing is recommended after meals to remove impacted food particles. Only one study, reported in 1950, supports this tradition. This study of 946 students compared brushing or rinsing with water within 10 minutes of eating compared to brushing upon awaking and before bed. Both groups showed evidence of new caries, 1.49 decayed surfaces (DS) versus 2.53 DS; however, there were several flaws in study design that challenge these results. Most importantly, this study has never been repeated to determine if these results are correct. Complete plaque removal before meals would prevent acid production by plaque bacteria from fermentable carbohydrates. This concept needs to be confirmed by science.

Research does support refraining from brushing for 60 minutes after ingesting foods or beverages with high-acid content. Softened enamel or dentin can be easily removed with toothbrushing.

Studies show that brushing once every 24-48 hours is sufficient to prevent gingivitis; however, when plaque is allowed to accumulate, gingivitis will occur in about 72 hours.

Toothbrushing frequency doesn’t always lead to reduced caries rates, as the brushing doesn’t always remove sufficient plaque. However, frequent brushing does apply fluoride-containing toothpaste to the teeth.

Clinical Implications: The quality of toothbrushing is still more important for oral health than the frequency.

Attin, T., Hornecker, E.: Tooth Brushing and Oral Health: How Frequently and When Should Tooth Brushing Be Performed? Oral Health Prev Dent 3: 135-140, 2005.

Listerine shows anti-inflammatory effects

The phenolic compounds used in Listerine and other comparable mouth-rinses have antibacterial properties and are used in antiseptics and disinfectants. The phenolic compounds display an inhibition of free oxygen radical activity. Previous research has shown that Listerine effectively reduced signs of inflammation, but did not reduce plaque scores.

Researchers at the University of Göteborg in Sweden compared Listerine, chlorhexidine, and saline for plaque, gingivitis and crevicular fluid reductions. The 21 test subjects participated in a cross-over study with a test period for each of the three products. Prior to the test period, subjects were given extensive oral hygiene instructions and professional cleanings twice a week for two weeks, to establish healthy oral tissues. Each subject underwent three test-periods, testing the assigned mouthrinse for two weeks without any other oral hygiene. A rinse-out period of two-weeks was set between mouthrinse tests to avoid any carry over of product effect. At the start and end of each test period, subjects received a professional tooth cleaning.

Those in the chlorhexidine group showed the lowest plaque scores, followed by the Listerine group and the highest scores were in the saline group. Gingivitis levels were lower when using Listerine, lowest with chlorhexidine and highest with saline. Some sites began the study with scores over zero. The totals for gingivitis scores of 2 at the end of testing were 11% for chlorhexidine, 14% for Listerine and 23% for saline. Gingivitis scores that shifted from 0 to 2 during the test periods were 7% of sites in the chlorhexidine group, 10% of sites in the Listerine group and 19% of sites in the saline group.

Gingival crevicular fluid flow showed similar results, with the greatest flow observed in the saline group, followed by the Listerine group and the chlorhexidine group.

Other studies also found that chlorhexidine controls plaque formation better than Listerine. However, the gingivitis scores were much closer between chlorhexidine and Listerine than the plaque scores, both in this study and in other studies. Researchers speculate that the effects of Listerine may be more profound when used after brushing as compared to using the rinse instead of brushing.

Clinical Implications: Patients using Listerine and other phenolic mourthrinses may exhibit reduced gingivitis due to the anti-inflammatory effects of the mouth-rinse ingredients.

Sekino, S., Ramberg, P.: The Effect of a Mouth Rinse Containing Phenolic Compounds on Plaque Formation and Developing Gingivitis. J Clin Perio 32: 1083-1088, 2005.