by Trisha O'Hehir
Full-mouth disinfection (FMD) is a popular topic these days and a relatively new term in periodontics. Several authors have discussed it over the years, but research reported in the mid-1990s by Dr. Marc Quirynen and his research team at Catholic University in Belgium brought it to the forefront of discussions. The theory behind FMD is to effectively rid all subgingival areas of periodontal pathogens in as little as 24 hours, avoiding the reinfection of untreated sites that might be expected when quadrants are treated a week or two apart.
Dr. Quirynen's first reports suggested extensive use of chlorhexidine for effective disinfection in cases of advanced perio. In subsequent studies comparing full-mouth instrumentation to quadrant visits, it was the instrumentation and not the chlorhexidine that made the difference. Sites treated within 24 hours showed 1.5 mm more pocket depth reduction on average than sites treated at two-week intervals. The FMD group also had a greater reduction in subgingival bacteria at the end of the study.
These findings are contrary to the tradition of treating a quadrant every two weeks. Research coming from one source that challenges the status quo will not go unchallenged itself. Several studies have been undertaken to either confirm or disprove the results reported by the group in Belgium. As you might expect, none of the studies are exactly like the first one, so comparisons are always difficult.
Researchers in Scotland repeated the study with a few changes in the design. They didn't use chlorhexidine, and they used both hand and ultrasonic instruments. The FMD was completed in one day with a two-hour appointment in the morning for one side of the mouth and a two-hour appointment in the afternoon for the other side of the mouth. In the original study, instrumentation was completed in one arch on one day and on the other arch the following day, using only hand instruments.
The Scottish study included 40 subjects and lasted six months. Unlike the Belgian study, improvement was seen in both groups. Pocket depth reductions were 1.6 mm to 1.8 mm for both groups. At six months, the average pocket depth for each group was 2.6 mm. Gain in attachment was greater in the non-smokers of both treatment groups compared to smokers, a difference of 0.4 mm.
Additional clinical indices were recorded for the quadrant group. Treatment for this group began in the upper right quadrant and proceeded clockwise around the mouth. As each quadrant was treated, the remaining untreated quadrants were measured for plaque levels, pocket depths, attachment levels, and bleeding upon probing. Untreated sites showed improvement prior to treatment. This was likely due to high levels of oral hygiene practiced by the subjects. To some researchers, probing at each visit is a form of treatment as it stirs up the subgingival bacteria and the bleeding can trigger an immune response.
Subgingival bacterial samples were taken from the deepest pocket in each quadrant at baseline, six weeks, and six months. Unlike the Quirynen study that reported differences between groups for bacteria in the pockets, no significant differences were observed between the FMD and quadrant groups for the five bacterial species tested in the Scottish study.
Now we have a challenge to the concept that untreated sites tend to reinfect treated sites, since both groups were equally healthy at the end of six months. According to these authors, there is no difference between FMD and the traditional quadrant approach.
Another research team in Turkey compared their variation of FMD to the quadrant approach. All instrumentation was done using local anesthesia, hand instruments, and included intentional removal of pocket epithelium and granulation tissue. The 100 study participants all received oral hygiene instructions at the beginning of the study and were given chlorhexidine for twice daily rinsing. Half the subjects were treated once a week for quadrant scaling and root planing. The FMD group was treated daily for four days. Each day they received full-mouth instrumentation. It wasn't clear who performed the instrumentation and if it was the same clinician for all patients. It wasn't made clear why full-mouth instrumentation was done daily instead of a quadrant each day.
After three months, both groups showed improvement but no clinical differences were observed between the groups. It was interesting to note that pocket depth reductions were not as great in this study compared to the previous studies. Both groups averaged less than 1 mm of pocket depth reduction.
The Belgian studies found FMD produced greater pocket depth reduction than treating a quadrant every two weeks. The Scottish study found no difference between FMD and weekly visits for quadrant instrumentation. The Turkish study compared weekly quadrant instrumentation to four days of full-mouth instrumentation without any clinical differences long-term.
These findings point out the variations between different treatment approaches and the lack of hard evidence to support one way over another. If time and attention are given to the treatment, it shouldn't matter if the visits are scheduled on a single day, two days, weekly, or biweekly.
Use the scheduling option that best fits your schedule and each patient's preference. Some clinicians prefer long appointments. I know I do. Some patients prefer to come in for four separate visits while others prefer to "get it over with" and just come in for one or two long visits, thus avoiding taking more time off from work. Use these scientific findings to add more flexibility to your schedule. The jury is still out on the most appropriate interval for periodontal instrumentation.
Trisha E. O'Hehir, RDH, BS, is a senior consulting editor of RDH. She is also an international speaker, author, instrument designer, inventor, and oral health detective. Her Web sites are www.perioreports.com and www.toothpastesecret.com. She can be reached at (800) 374-4290 or at [email protected].
References available upon request.