Stirring the Gumbug Pot

Sept. 1, 2007
Dental hygienists often ask me if there is any value in professional irrigation.

by Lynne H. Slim, RDH, BSDH, MSDH

Dental hygienists often ask me if there is any value in professional irrigation. In particular, they want to know if the fee they charge to perform this procedure is justified. I’ve often struggled with the answer, but this is actually one of the intraoral procedures that has strong evidence against it. Does this statement shock you or not surprise you?

Let’s take a close look at the evidence so you can decide for yourself.

Clinicians have been using locally delivered anti-infective pharmacological agents for well over two decades.1 We are fortunate to have systematic reviews of a large number of clinical trials that determined the efficacy of anti-infective agents used on their own or combined with SRP. Sometimes when clinical trials are reviewed collectively, some studies are thrown out due to poor quality. After appropriate studies are collected and reviewed, a meta-analysis (special statistical technique) is performed and the results are interpreted by a panel of reviewers. Then a recommendation is made based on the strength of the evidence, and the evidence can be applied to clinical decision-making as well as the patient’s circumstances and preferences.

In 2003, the American Academy of Periodontology (AAP) conducted a systematic review of a large collection of studies on professional adjunctive irrigation. The studies that were included in the meta-analysis compared chlorhexidine (CHX) irrigation plus SRP to SRP alone. The reviewers concluded that no evidence was found for an adjunctive effect on reduction of probing depth or bleeding on probing.

So, what should you do if you find yourself in a practice that still charges for professional adjuctive irrigation? This is a really tough question to answer but I’ll take a stab at it. When I look at this issue and other questionable therapies (especially those that promote increased practice profitability and not what’s best for the patient), I think about qualifications for the practice of dental hygiene and dentistry. Laws and rules for practice seem to uphold the lowest minimum standard for practice, but they do not hold professionals accountable to a skill level that promotes quality. To ensure competency by a practicing clinician, a true professional needs to comply with external competence measures such as continuing education courses. The other important component is for the professional to reflect ethically about his/her choice of therapies and whether or not an acceptable standard of care is being met. Anti-infective nonsurgical periodontal therapy does not include adjunctive professional irrigation as part of the standard of care. Does this mean that you should forego this step after debridement? Not if you feel you are flushing out debris and that it has some therapeutic value.

If you choose to irrigate before and after SRP, a better choice of a topical antimicrobial is povidone iodine. There is some evidence that unlike CHX (which does not work), povidone iodine works much better and is inexpensive to deliver in a pocket. Slots recommends 10 percent povidone iodine applied repeatedly by an endodontic syringe to obtain a contact time of at least five minutes. If you are delivering povidone iodine in an ultrasonic unit, 10 percent povidone iodine is diluted by mixing one part solution with nine parts of water.2

I urge all practicing hygienists to challenge each other in determining the best standard of care when delivering non-surgical periodontal therapy. Members of the periotherapist yahoo group that I own and manage e-mail and share information because they want to provide the best care to their patients. I greatly admire those members of the group who take the time to post and discuss various issues that relate to periodontal therapy, and there are even international members who share yet another perspective on therapeutic decision making.

Nonsurgical mechanical therapy is the gold standard of care in reducing supra- and subgingival bacteria. Chronic periodontitis is indeed a bacterial infection, as well as a mixed infection in which the subgingival microbiota is organized in such a way that the biofilms are in continual flux.3 In debriding pockets, we break up partnerships, “stir the gumbug pot,” and thoroughly confuse the little buggers. When I explain debriding a pocket to patients, I compare the subgingival biofilm to cobwebs. I tell patients I am disorganizing the different cobwebs that spiders create and forcing the spider(s) to start over from scratch. I also emphasize that it takes only three to seven days for the majority of subgingival gumbugs to repopulate a periodontal pocket!4

I recently read a new study on the microbiological findings after nonsurgical therapy using curettes, Er:YAG laser, and sonic and ultrasonic scalers, and I’m eager to share the findings with my dedicated readers. In “stirring the gumbug pot” with these instruments, researchers wanted to find out how well each instrument reduced the total number of certain selected periodontopathogens in treated pockets three and six months after therapy. In addition, the researchers collected information that documented patients’ perceptions of each treatment modality and asked questions about pain, unpleasantness, and inconvenience during therapy.3

A total of 288 subgingival biofilm samples were collected before instrumentation, and again at three and six months post-therapy. Target microorganisms were identified with a PCR/DNA probe test which analyzes regions of DNA within bacterial cells. Red/orange complex bacteria including P. gingivalis (Pg), P. intermedia (Pi), T. forsythensis (Tf) and T. denticola (Td) were counted, as was A. actinomycetemcomitans (Aa), which is associated with localized aggressive periodontitis.

All subjects received oral hygiene instructions three to five weeks before the study started, and a total of three to five appointments were scheduled, which included supragingival scaling and polishing. To reduce pathogens on all other intraoral surfaces, subjects rinsed twice a day with 0.1 percent CHX. All other pathology, including dental caries, defective pulpal restorations, and pulpal pathology, were eliminated to prevent bacterial seeding.

Therapeutic Procedures

Hand instrumentation was performed with Hu-Friedy standard and Mini-FiveTM Gracey curettes. An Er:YAG laser device from KaVo (Germany), combined with a calculus detection system, was selected for laser treatment with an energy level of 160 mJ/pulse and a repetition rate of 10 Hz with water irrigation. Sonic instrumentation was conducted with a SONICflex® system by KaVo with constant water irrigation. The ultrasonic instrument selected was the piezoelectric device Piezon Master 400 (EMS, Switzerland). Three different ceramic tips were used at a frequency of 28,000 Hz with constant water cooling. All mechanical debridement was performed under local anesthesia. Laser therapy was terminated when the calculus detection device indicated the absence of calculus deposits on the root surface. Sonic and ultrasonic instrumentation was performed blind, meaning that a periodontal endoscope was not included in the research design.


All subjects completed active therapy, including the three- and six-month follow-up visits. Of the 288 periodontal pockets, 72 received hand instrumentation, 72 laser therapy, 72 sonic scaling, and 72 piezo ultrasonic. Each one of the five periodontopathogens was reduced at three months following therapy, but increased in prevalence at six months. At six months postoperatively, the pockets were infected with periodontopathogens at the same values (numbers) as those obtained at baseline! This emphasizes the importance of periodontal maintenance for periodontal patients because maintenance debridement is critical for continued bacterial suppression!

Patients reported that hand instrumentation was significantly more painful, unpleasant, or inconvenient than sonic and ultrasonic instrumentation, and they preferred sonic debridement to laser instrumentation. All patients received adequate local anesthesia, so there must have been something about hand instrumentation or laser therapy that created an unpleasant perception. The researchers theorized that stress on jaws or neighboring teeth, an open mouth, or turned head were factors that might influence patients’ perceptions. In addition, patients preferred ultrasonic instrumentation to laser instrumentation, which researchers concluded was due to the unpleasant smells.

In discussing the antimicrobial effects of the four treatment modalities -curettes, laser, piezo ultrasonic and sonic - the authors emphasized that specific microbial associations have been observed in pockets. It is extremely uncommon to find red complex gumbugs (Pg, Tf, Td) in the absence of orange complex gumbugs. After initial debridement of a periodontal pocket, bacteria regrow and repopulate to pretreatment values only three to seven days after treatment, but (and this is a big but) with an altered composition.3 Since it takes approximately six months or more for the original red/orange complex partnerships to become reestablished, it’s imperative that periodontal patients maintain a consistent recare schedule with optimum home oral hygiene to keep these partnerships broken. In other words, prevent complex communities from reestablishing themselves. I guess we could compare the pathogenic bacteria community to one that keeps getting hit with a tornado every three to six months! Don’t hesitate to use this simple analogy when talking to periodontal patients about the importance of three-month recare.

It was clear that all four nonsurgical treatment modalities - curettes, Er:YAG laser with a deposit detection device, sonic, and ultrasonic scalers - resulted in a significant reduction in the amounts and prevalence of the five periodontopathogens for up to three months. No treatment modality was superior to the other except when considering patient perception, as mentioned above.

Research studies such as the one described here are very important for hygienists to review. Not only do our patients need to understand what we are doing when we debride pockets, we need to support research that compares and contrasts instrumentation techniques. In “stirring the gumbug pot” nonsurgically, it’s essential for us to focus on antimicrobial effects and ultimately on overall health outcomes.

About the Author

Lynne H. Slim, RDH, BSDH, MSDH, is a practicing hygienist/periodontal therapist who has more than 20 years’ experience in both clinical and educational settings. She is also president of Perio C Dent Inc. (Perio-Centered Dentistry), a practice-management consulting firm that specializes in creating outstanding dental hygiene teams. Lynne is a member of the Speaking and Consulting Network (SCN) that was founded by Linda Miles, and has won two first-place journalism awards from ADHA. Lynne is also owner/moderator of a periodontal therapist yahoo group: She can be contacted at [email protected].


1. Hanes PJ, Purvis JP. Local anti-infective therapy: pharmacological agents. A systematic review. Ann Periodontol 2003; 8(1): 80.

2. Slots J. Selection of antimicrobial agents in periodontal therapy. J Periodont Res 2002; 37: 389-398.

3. Derdilopoulou FV, Nonhoff J, Neumann K, et al. Microbiological findings after periodontal therapy using curettes, Er:YAG laser, sonic and ultrasonic scalers. J Clin Periodontol 2007; 34: 588-598.

4. Socransky SS, Haffajee AD. Periodontal microbial ecology. Periodontology 2000 2005; 38: 135-187.