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
Root Surface Smoothness

Root surface smoothness has long been a tradition of dental hygiene and periodontal education. Various instruments and therapies have been evaluated over the years regarding smoothness as measured on both extracted teeth and those scheduled for extraction. A small study was conducted in the early 1980s that evaluated the clinical effects of intentionally roughened root surfaces. A group of 12 patients provided a total of 18 test teeth. Scaling, root planing, and plaque control instructions were provided two weeks prior to surgery. The surgical procedure used for all patients was the modified Widman flap. During surgery, more root planing was performed to produce smooth hard root surfaces. A No. 2 round bur was used to roughen the test surfaces, and several shallow horizontal grooves were then cut into those surfaces. The control surfaces were left as smooth as possible. Some bone recontouring was done to allow better adaptation of the tissue flap. Following surgery, both the test and control groups were seen for dental hygiene services every three weeks.

Results were measured at four months. Although both groups demonstrated good healing, there were no significant differences between them. The test teeth that were roughened with a bur showed a 5 mm reduction in pocket depth and a 4 mm gain in attachment. Pocket reduction in the control group that was root planed to a hard smooth surface was 4 mm and the gain in attachment was 3 mm. Since these figures vary by only one millimeter, the difference is not clinically significant.

Clinical Implications: It is clear from this study that rough root surfaces showed healing similar to smooth hard root surfaces. This study dispels the tradition of requiring smooth surfaces for healing.

Khatiblou, F., Ghodssi, A.: Root Surface Smoothness or Roughness in Periodontal Treatment. J Perio 54: 365, 1983.

The role of bubbles in bacterial biofilm removal

Biofilm is a sticky mass of bacteria, polysaccharide slime and water that is best removed by mechanical means – toothbrush, floss, and other tools. Power toothbrushes often generate a fluid stream containing bubbles that flow over tooth surfaces. Studies published in engineering journals have shown that bubbles entrapped in a liquid are capable of removing particles and adherent bacteria from surfaces. These findings suggest that increasing fluid velocity and decreasing bubble size could results in greater bacterial removal, and that slow streams of bubbles might be more efficient than fast streams at removing bacteria.

Engineers at Brigham Young University in Provo, Utah evaluated various fluid speeds and bubble sizes for the removal of Streptococcus mutans biofilm grown in a laboratory. The bacteria were grown on a glass slide suspended in a Plexiglas® container under 6 mm of fluid. Each biofilm container had 10 mm of air space above the fluid and a rubber septum at the bottom to allow penetration of a needle. Through this needle, artificial saliva was forced in at different velocities with varying sizes of bubbles. Glass slides were removed and placed on an image scanner to capture a picture of the remaining biofilm for analysis. Tests were undertaken after 16 hours of biofilm formation. Slower velocity with larger bubbles was more effective for biofilm removal than slow velocity with no bubbles. However, with increased velocity, sheer forces were greater and the bubbles became a hindrance and slowed biofilm removal.

This was a laboratory study with a single species bacterial biofilm on a flat surface. Both fluid dynamics and surface tension are important aspects to be considered when designing products for biofilm removal.

This study was funded by Philips Oral Healthcare, makers of Sonicare®.

Clinical Implications: These laboratory findings provide information for power toothbrush and oral irrigator companies to consider when developing new products.

Parini, M., Eggett, D., Pitt, W.: Removal of Streptococcus Mutans Biofilm By Bubbles. J Clin Perio: 32: 1151-1156, 2005.

Periostat® doesn’t change intestinal flora

Subantimicrobial dose doxycycline or Periostat, is taken twice daily for no more than nine months to add benefit to scaling and root planing. Periostat works not by killing bacteria but by anti-inflammatory and anticollagenase effects. Its use has not been shown to change the oral flora in any detrimental way. Despite these findings, questions have been raised concerning its effect on intestinal and vaginal flora.

CollaGenex Pharmaceuticals, Inc. provided funding to determine the effects of Periostat on intestinal and vaginal flora. This multicenter study involved researchers in periodontal clinics at the University of Pittsburgh, Ohio State University and the University of Florida. A total of 55 patients completed all the visits over the nine-month study period.

Subjects were all diagnosed with moderate to severe, chronic periodontitis, and all received subgingival scaling and root planing at the start of the study. Subjects were instructed to take their assigned pills twice daily for nine months. Half the group was given Periostat and half received an identical looking placebo.

At baseline, three- and nine-month visits, both male and female subjects were instructed to bring a stool sample to the clinic, using the kits provided. Female subjects were asked to provide a vaginal flora sample. Not as many volunteered as the researchers had hoped for, and problems with the sampling kits resulted in some samples being contaminated by air. However, basic comparisons were made regarding vaginal flora. No tests were done to determine resistance to various antibiotics.

Nine months of Periostat usage did not result in a shift in the normal flora of either the intestine or vagina. There was no overgrowth of opportunistic bacteria. Cultures of the intestinal bacteria were tested with doxycycline and several other antibiotics, but no resistance was evident.

Clinical Implications: Periostat is safe to use in combination with scaling and root planing for anti-inflammatory and anticollagenase effects and will not change the normal intestinal or vaginal flora.

Walker, C., Preshaw, P., Novak, J., Hefti, A., Bradshaw, M., Powala, C.: Long-Term Treatment With Sub-Antimicrobial Dose Doxycycline Has No Antibacterial Effect on Intestinal Flora. J Clin Perio 32: 1163-1169, 2005.

Less pain when treatment does not coincide with premenstruation

Pain perception varies between men and women due to hormonal differences. Over 50 years ago dental researchers reported hemorrhagic lesions associated with premenstruation. An increase in gingival exudate and increased tooth mobility have also been reported during the menstrual cycle.

Researchers at Ege University in Turkey measured pain experience following supra and subgingival instrumentation performed right before or within the first few days of the subject’s menstrual cycle against instrumentation performed after the menstrual cycle. A split-mouth study design was used, with one quadrant of instrumentation performed on one side of the mouth, and the second quadrant performed for the same appointment length with the same amount of anesthesia on the other side of the mouth. One quadrant was treated within a time frame of three to four days prior to menstruation up to the third day of menstruation. This was considered the premenstruation time frame. The other time frame was post-menstruation, the first week after menstruation.

Pain experience was measured on a 100 mm visual analog scale. Pain scores during premenstruation were 22 compared to post-menstruation scores of 15. One subject had an extremely wide range of pain, from 15 during post-menstruation to 69 during premenstruation.

Clinical Implications: Although this was a small study and findings should not be generalized, you might want to consider scheduling non-surgical visits after a woman’s menstrual cycle to provide a more comfortable experience.

Özçaka, Ö., Biçakç, N., Köse, T.: Effect of the Menstrual Cycle on Pain Experience Associated with Periodontal Therapy. Randomized, Pilot Study. J Clin Perio 32: 1170-1174, 2005.

Bleeding upon probing linked to disease progression

Periodontal disease left untreated can ultimately lead to tooth loss, which is a major public health problem facing a growing number of adults. Preventive strategies are needed for adults, especially the elderly as they are the population most at risk.

Bleeding upon probing (BOP) is associated with gingival inflammation and is a risk indicator for advancing disease. Based on research published in 1989, the presence of BOP was considered a poor predictor of attachment loss, although 30% of bleeding sites did show disease progression over time.

Researchers in Japan evaluated 229 non-smoking 70-year-olds to determine the relationship between BOP and disease progression. Subjects received an oral exam at baseline and each year during the three-year study.

More than 13,000 sites were evaluated. The frequency of BOP was related to attachment loss over the study period. Sites that bled at two of the four visits were 2.5 times more likely to show advancing disease than sites that didn’t bleed. Sites that bled at each of the four visits were 6.2 times more likely to show advancing disease.

Clinical Implications: Bleeding upon probing should be considered a predictor of periodontal disease progression in older adults. Since sites that do not bleed rarely show advancing periodontitis, zero bleeding upon probing should be a clinical goal of treatment.

Rahardjo, A., Yoshihara, A., Amarasena, N., Ogawa, H., Nakashima, K., Miyazaki, H.: Relationship Between Bleeding on Probing and Periodontal Disease Progression in Community-Dwelling Older Adults. J Clin Perio: 32: 1129-1133, 2005.

Magnesium deficiency linked to periodontitis

Magnesium has a strong relationship with the body’s immune response. Hypomagnesemia is associated with an exaggerated inflammatory response to a bacterial infection. Magnesium deficiency is also observed with low bone mass and may manifest itself in the oral cavity as loss of crestal bone and perhaps bone loss linked to tooth loss.

Researchers at the Ernst Moritz Arndt University in Greifswald, Germany evaluated subjects in a large study of residents of the Pomerania area of northeast Germany. Study subjects received a thorough periodontal examination on one side of their mouths, either the right or left, based on randomization. Serum magnesium and calcium levels were measured and subjects were asked about oral supplementation. Over 4,000 subjects were examined, but since chronic periodontal disease is seen more often in subjects over 40 years of age, the sample was limited to those 40 years and older – nearly 3,000.

Despite supplementation, magnesium blood levels remained constant. No differences were observed between those taking supplementation and those not. Magnesium influences the intercellular processes without elevating serum levels. Those who reported taking magnesium had less periodontal disease and more teeth than those who didn’t take supplements.

Clinical Implications: Magnesium supplementation may prove to prevent tooth loss and prevent periodontal disease. Controlled trials are needed to determine optimum levels and the best delivery system. Until then, ask patients if they are taking magnesium supplements to see if you can identify a healing benefit in those who take it.

Meisel, P., Schwahn, C., Luedemann, J., John, U., Kroemer, H., Kocher, T.: Magnesium Deficiency is Associated with Periodontal Disease. J Dent Research 84: 937-941, 2005.