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.

Tongue coating, bad breath, and periodontal disease

How are these three related, asked Dr. Mel Rosenberg in a guest editorial in the Journal of Clinical Periodontology. Dr. Rosenberg is an expert in oral malodor, and has published research on this topic. He is a founding member, and currently president of the International Society for Breath Odor Research.

Bad breath is primarily an oral problem that is awkward and embarrassing for millions worldwide. It can be a warning sign of medical and dental disease, however research is inconclusive as to the connection between periodontal disease and bad breath. The most likely explanation for the differences reported between various research studies is the impact of the tongue on malodor. As far back as 1930, Dr. Grapp reported the connection between bad breath and tongue coating. Dr. Tonzetich and his coworkers also reported a greater impact on bad breath from the tongue, than the periodontium. The surface size of the tongue and its exposure to air complicates measurements of oral malodor, as it relates to periodontal disease.

Periodontal pockets are relatively sealed as compared to the tongue’s surface, reducing their impact on bad breath. A similar argument is made for foul smelling tonsilloliths (tonsil stones) that may or may not cause bad breath, depending how exposed they are to air.

One theory suggests that odor associated with periodontal disease emanates from exposed interdental plaque. This is confirmed in studies showing that flossers have significantly less mouth odor than non-flossers. Perhaps the malodor from un-flossed interdental areas today will predict future periodontal problems––a useful point for patient motivation. Dr. Rosenberg theorizes that the bacteria coating the tongue play a role in the initiation and progression of periodontal disease.

Clinical Implications: Deep and gentle cleaning of the tongue is recommended to eliminate bad breath. More research studies are needed to determine the extent to which tongue cleaning impacts periodontal health.

Rosenberg, M.: Bad Breath and Periodontal Disease: How Related Are They? Guest Editorial J Clin Perio 33: 29-30, 2006.

Looking at the evidence for stannous fluoride

Evidence based care takes into consideration the research, the clinician’s skills and knowledge, and the patient’s desires. To evaluate the research, a question is asked and then studies that meet certain criteria are evaluated. Chemical agents are often used to compensate for poor mechanical plaque removal; stannous fluoride is an example. Stannous fluoride combined with tin has been available for several decades in rinses, pastes, and gels for reducing gingivitis. Two researchers from the Department of Periodontology at the Academic Center for Dentistry in Amsterdam undertook a review of published research on this subject. The question they asked was what effects do stannous fluoride products have on plaque and gingivitis in patients with gingivitis.

Searches through PubMed and the Cochrane Registry produced a total of 746 articles on the topics of stannous fluoride and gingivitis. Eliminating duplicates brought the number of articles to 542. A set of criteria established by this paper’s authors for study length, randomization, and study subject characteristics further reduced the list to 36 articles. These studies were read and it was determined that only 15 studies fulfilled the established criteria for inclusion in this review. Studies needed to be at least six months in length, randomized, and data presented in figures that could be compared, not simply a graph. Despite the number of studies on this subject, not many follow these basic criteria and therefore can not be compared.

In only 15 studies, comparisons were still difficult, as more variations were evident between studies: different indices used, adequate to poor compliance of subjects, and incomplete reporting are a few. Some studies showed that stannous fluoride products were superior to sodium fluoride products for reducing plaque and gingivitis. Other studies showed no difference. The plaque and gingivitis reductions reported for stannous fluoride products were slight. The only thing that all studies agreed upon was stain. Use of stannous fluoride products results in stain formation to various degrees.

Clinical Implications: Stannous fluoride pastes/gels may cause slight reductions in plaque and gingivitis, and they will stain the teeth.

Paraskevas, S., van der Weijden, G.: A Review of the Effects of Stannous Fluoride on Gingivitis. J Clin Perio 33: 1-13, 2006.

Subgingival instrumentation changes pocket environment

We know that subgingival instrumentation reduces the number of bacteria, but just how quickly do they return? Researchers in the Departments of Periodontology and Oral Microbiology at the Academic Center for Dentistry in Amsterdam monitored 22 treated pockets to find out. Twenty-two volunteers, half smokers, half non-smokers participated in the study. One interdental periodontal site on a single rooted teeth was identified for each subject as the test site.

Phase I of the study included a maximum of six weeks for oral hygiene instructions and supra and subgingival instrumentation of all teeth except the identified test sites. Both ultrasonic and hand instruments were used. Subjects were instructed on appropriate interdental cleaning, from floss to interdental brushes.

Phase II started one week after Phase I. A single session of subgingival instrumentation was carried out at the test sites, using only hand instruments. Subjects were instructed to continue daily oral hygiene, including twice daily rinsing with chlorhexidine and cleaning the interdental test site with an interproximal brush dipped in chlorhexidine. This approach prevented supragingival plaque or bacteria in the saliva from influencing subgingival bacterial counts.

Bacterial samples were taken with paper points from the test site four times: before instrumentation in Phase II, immediately after instrumentation, one week later, and two weeks later. Mechanical instrumentation of the subgingival area did not eliminate a single bacterial species, but did reduce the total number by 42 fold. The balance of one species to another did change, as some pathogens did not colonize to the level they had in the untreated pocket. Perhaps disruption of the biofilm resulted in more free floating bacteria that were easily phagocytosed by PMNs in the pocket. This suggests that the host response plays an important role in controlling bacterial growth after treatment.

Clinical Implications: Subgingival instrumentation with hand instruments reduces the number, but not the presence of bacteria, however, the treated pocket seems to provide a barrier to proliferation of the pathogenic species. I wonder if these data would vary if an ultrasonic scaler had been used to flush out the pocket?

Rhemrev, G., Timmerman, M., Veldkamp, I., Van Winkelhoff, A., Van der Velden, U.: Immediate Effect on Instrumentation on the Subgingival Microflora in Deep Inflamed Pockets Under Strict Plaque Control. J Clin Perio 33: 42-48, 2006.

Ultrasonic tip wear reduces effect

Ultrasonic scaler use is increasing and research has demonstrated comparable effectiveness when compared to hand instruments. Normal use leads to wear and reduced tip length. It was assumed that such wear would compromise tip displacement. Until this study, no one had measured the effect of wear on ultrasonic tip displacement. Ultrasonic scaler power settings control the number of stokes per second and the displacement amplitude is the width of the ossilating tip stroke.

Researchers at the University of Birmingham in the UK designed a study to measure the effect of wear on the performance of several ultrasonic scaler tips when held in the air or against a tooth surface at varying pressures. Three Dentsply focused spray inserts (FSI) were selected for testing: FSI-100, FSI-1,000, and FSI- SLI-10S. Five inserts of each design were tested, for a total of 15 inserts. The inserts were all tested in a Dentsply Cavitron SPS 30K unit.

Each insert was tested when it was new, and then with 1 mm of tip removed, and again with 2 mm of tip removed. Tip wear was created using a rotating stone. Tip displacement amplitude was measured with a scanning laser vibrometer making 10 scans at each of the three settings. The tip was tested in the air before touching the extracted tooth, and then touching the tooth with 0.5 N of pressure, and then with 1.0 N of pressure.

Each set of five tips of the same design showed some variations from one to another. Most of the tips showed a significant reduction in displacement amplitude with wear. Clinicians using a worn tip may experience reduced effectiveness and turn the power up. This is not likely to help as previously reported research showed that the displacement amplitude is not altered with increased power.

This study was funded by Dentsply International.

Clinical Implications: Excessive wear shortens an ultrasonic scaler tip and is likely to change the displacement amplitude, and therefore the effectiveness of the tip for calculus removal.

Lea, S., Landini, G., Walmsley, A.: The Effect of Wear on Ultrasonic Scaler Tip Displacement Ampitude. J Clin Perio 33: 37-41, 2006.

Full-mouth disinfection (FMD) should be an option

Studies by various research groups present different findings when comparing FMD to the traditional quadrant approach to periodontal instrumentation. Differences are due primarily to variations in study design, and therefore comparisons between studies are not valid. Is FMD better than the traditional quadrant approach? The answer depends on how you measure “better.”

According to research published in 1991, the bacterial load within the pocket is reduced to 0.1% of the starting level following subgingival instrumentation. Within a week, the number of subgingival bacteria is back to pretreatment levels. Fortunately, the bacterial makeup is less pathogenic than before. Other areas of the mouth may also harbor bacteria and be a potential source of re-colonization.

The studies reported ten years ago by Dr. Quirynen and his team in Belgium looked at the transmission of bacteria from untreated sites to treated sites, focusing on the concept of re-colonization and translocation of bacteria.

Interdental oral hygiene was not introduced for the quadrant group until instrumentation was completed in each quadrant. This means that daily interdental oral hygiene was delayed six weeks for the last quadrant in this group. Those in the FMD group received all instrumentation and oral hygiene instructions within 24 hours. They also used chlorhexidine in every form and for every niche within the oral cavity to reduce the bacterial count.

When other researchers introduced daily interdental oral hygiene from the start of their studies, no outcome differences were observed between the two treatment approaches. The interdental oral hygiene appears to reduce the translocation of bacteria from untreated sites to treated sites. Other study design variations include time between visits, antimicrobial uses, and hand vs. power scaling.

We do know that both quadrant and FMD approaches to periodontal instrumentation reduced infection, pocket depths, and bleeding and in some cases result in a gain of clinical attachment. Rather than forcing a choice between the two approaches, both are available.

Clinical Implications: Both approaches work. One camp will favor the traditional quadrant, four visit approach, while the other camp will suggest the FMD approach should be the treatment of choice. In addition to the scientific evidence supporting one or the other, patient preference and economic benefits must also be taken into consideration. Select the treatment approach that best fits the patient, the clinician, and the practice.

Quirynen, M., Teughels, W., van Steenberghe, D.: Impact of Antiseptics on One-State, Full-Mouth Disinfection. J Clin Perio 33: 49-52, 2006.

Molar loss in periodontally treated patients

Molars with furcation involvement respond less favorably following treatment than molars with no furcation involvement. Furcation involvements are sites of recurrent disease for several reasons. Accessory pulpal canals, anatomy that impedes accessibility for daily cleaning as well as professional instrumentation, and sometimes morphological features like enamel pearls contribute to disease progression.

Retrospecitve studies published in 1978 and 1982 reported molar tooth loss of 7% and 10%. In the current study, researchers at the University Hospital in Heidelberg, Germany evaluated the records of patients in their clinic who received periodontal therapy between 1992 and 1995, and also received five years of periodontal maintenance therapy. They evaluated data on 505 molar teeth in 71 patients. Nine patients had aggressive periodontitis and 62 had chronic periodontitis.

Subjects were classified as smokers or non-smokers. Anyone who reported smoking 10 cigarettes per day or less was categorized as a non-smoker. Plaque levels were also evaluated. All patients received non-surgical therapy and oral hygiene instructions. Surgical procedures were provided as needed, including access flap surgery, GTR, tunnel preparations, resective procedures, and extractions.

Furcations were classified as Degree 0, not probable (200 molars); Degree I, up to 3 mm of horizontal loss (116); Degree II, more than 3 mm of horizontal loss, but not through and through (122); and Degree III, through and through destruction of bone (67).

A total of 71 molars were lost (14%), 33 during active therapy and 38 during the five years of supportive maintenance therapy.

Clinical Implications: Molar survival after periodontal therapy, including surgical and non-surgical, is very good. More maxillary molars are lost than mandibular molars. Smoking and the severity of the furcation involvement are predictors of molar loss.

Dannewitz, B, Krieger, J., Hüsling, J., Eickholz, P.: Loss of Molars in Periodotnally Treated Patients: A Retrospective Analysis Five Years or More After Active Periodontal Treatment. J Clin Perio 33: 53-61, 2006.