Keyes Technique: The Fallacy of The Usage of Hydrogen Peroxide in Periodontal Therapy
by Dinh X. Bui, D.D.S., M.S.

Keyes Technique: The Fallacy of the Usage of Hydrogen Peroxide in Periodontal Therapy
On January 1978, Paul H. Keyes, working for the National Institute of Dental Research, introduced the use of phase-contrast microscopy and chemotherapy in the diagnosis and treatment of periodontal lesion. This later is known as the Keyes technique in treatment of periodontal disease. The more accurate term is “microbiologically modulated periodontal therapy”. The treatment concept became so popular such that the usage of hydrogen peroxide for the treatment of periodontitis is still being used by various general dentists. The following paper is to break down the Keyes technique and the pros and cons of hydrogen peroxide adjunctive therapy. The paper also discusses about researches concerning the usage of systemic antibiotics as an adjunctive treatment to Periodontal therapy.


Overview of the Keyes technique

The Keyes technique has the two major components: monitoring and therapy.

1. The monitoring component consist of the use of the phase contrast microscopy to evaluate qualities and relative quantities of the bacterial population in subgingival plaque samples. These observations served as the guide to modulate the therapy. Periodic microscopic assessment of microflora in their gingival crevices and pockets should be provided to the patient.

2. The treatment phase consists of three components: the local mechanical therapy, the local chemical therapy, and the systemic antibiotic therapy (systemic chemotherapy).
a. The local mechanical therapy: achieved by scaling and root planing plus mechanical oral hygiene effort.
b. The local chemical therapy: achieved by patient oral hygiene with baking soda and peroxide. This application of saturated salt solution deep into the sulcus socket spaces will eliminate or reduce potentially periodontopathic bacterial population.
c. The systemic antibiotic therapy: achieved by followed up after mechanical therapy with a course of tetracycline HCl, 250mg q.i.d. for two weeks, except in the case of pregnant women nor drug allergy nor kidney disease patient. After two weeks of systemic chemotherapy, deposits from representative pockets or lesions are reexamined microscopically and at which time microscopic fields should be negative for motile forms and white blood cells.

Composite drawing depicting typical bacterial patterns found in destructive periodontitis, marginal gingivitis, and excellent gingival health.
1. Destructive periodontitis: brush formation, consisting of turbulent mass of spirochetes attached to branching chains of rods colonized by coccoidal forms; oral protozoa such as T tenax (trichomonads) and E. Gingivalis (ameba), large mass of accumulated crevicular leukocyte; large gliding rods swimming in the fluid environment, attached to static forms as palisading rods or organized into a rosette formations, spirochetes seen as small particles.
2. Marginal gingivitis: Low level of crevicular leukocytes, cluster of unorganized motile forms such as clocked arm rods, small spinning or corkscrew rods, low number of loosely or isolated spirochetes, and long spiral rods.
3. Excellent gingival health: Small motile cocci, no spirochetes or motile rod present. Crevicular leukocyte are scarce throughout a loose networks of thread forms colonized by coccoid cell. No spirochetes, brush formation, larger motile rods, amebae, or trichomonads were detected.

Keyes technique, Paul Keyes.
1. Goal
Our goal is “to help the patient keep bacteria and bacterial by product at nonpathogenic levels and thereby abate or arrest further destruction and allow natural healing to occur. Patient must be well informed about the role of bacteria and the benefit of reduce germ life on all accessible tooth surface.”

2. Rationale for the regimen
“Our diagnostic and therapeutic regimen is based on the following proposition:”
a. Certain bacterial complexes firmly or loosely attached to radicular surfaces are not compatible with periodontal health (this includes the variety of motile organism)
b. The motile bacteria and white blood cells residing in sulcus-pocket spaces can be sampled and readily examined chairside by phase contrast microscopy.
c. The prevalence of certain bacterial population can be used to predict potentially periodontopathic conditions.
d. The population in question can be prevented from accumulating or can be suppressed by appropriate therapy.
e. When microbiological population are controlled, progressive destruction of the periodontal tissue abates and diminished greatly.

3. Diagnostic method
a. microscopic assessment of motile organism: plaque samples from several representative root surface were collected by mean of a curet or periodontal file, mount on the glass slide, then view by the practitioner and/or patient.
i. healthy or stable individual: very small motile cocci, occasional white blood cell and none of the larger motile rod and spirochetes - nonperiodontopathic microscopic finding.
ii. lesions: larger motile rods, spirochetes, and numberous white blood cells.
b. Gingival bleeding point: assessing tissue condition by gently passing a perio probe in the sulcus pocket spaces. Representative bleeding point, shown to the patient, demonstrated evidence of capillary fragility associated with erythemogenic bacterial by-products and/or ulceration within the gingival crevice or pockets. Other assessments can be pocket depth, tooth mobility, radiographs, oral photograph, plaque disclosing green food color. Plaque and inflammation score or other indices, according to Keyes, does not provide appropriate sensitive diagnostic data.

4. Mechanical therapy
a. Tooth brushing
b. Flossing
c. Irrigation: water irrigation whenever possible after eating.

5. Chemical therapy
a. Dentifrice: a mixture of baking soda, few drops of water, 3% hydrogen peroxide is worked between teeth with tooth brush, dental floss, or toothpicks. The teeth are brushed with the mix which is left in place for one minute. Table salt also can be used, or Epsom salt on patient with low sodium diet.
b. Fluoride treatment: for treatment of root sensitivity and root caries. Tray can be made.
c. The rationale for salt therapy: motile bacteria comes in contact with salt solution will cease their motility. Many bacteria become shriveled, distorted, almost all rods show segmented contractions of their intracellular contents. This reaction is lethal for many organism.

6. Systemic tetracycline
a. Dosage: Tetracycline HCl, 250mg, q.i.d., two week duration, then stopped or reduced to two capsules per day for ten weeks if the microscopic field are negative for motile and WBC.
b. Anticipated result: negative microscopic field for motile forms and WBC. If not, patient is reinstructed and continue on antibiotics for another week. Patient are reexamined microscopically and pockets are scaled every two to three months.

7. Expected result of the therapy
a. Populations of spirochetes and larger motile rods have fallen to nondetectable levels. The WBC counts may decline to less than five cells per field.
b. Rapid reduction in gingival inflammation, bleeding, and suppuration should occur. Gradual improvement of gingival tissue accompanied the recession, and disfiguration appears to be minimal.
c. Reduction of tooth mobility with tighter feeling on the teeth.
d. Bone resorption ceased, or abated to imperceptible degree. Bone recontour and change in density may occur slightly.
e. Sulcus pocket depth either reduced or stay the same in six or twelveth month follow up.

Long term effects
of antimicrobial therapy
Thomas E. Rams et al., 1985.

Subjects: 47 adults with advanced periodontitis were treated and followed for at least 3 yrs and up to 6.5 yrs. Within this group, 10 patients were refractory cases following conventional periodontal therapy provided by periodontist. All patient has good general health and at least 22 teeth. No systemic medical disorders. None of the subjects had received any type of antibiotic therapy for the previous 6 months.

Results:

Bleeding assessment:

 

 

 

Frequency distribution of sulcular bleeding score

 

 

No of patient

0

1

2

Baseline

47

56.2%

2.7%

41.2%

3-4yrs after

17

63.3%

16.2%

.5%

4-5 yrs after

14

85.3%

11.8%

2.9%

5-6.5yrs after

16

88.4%

11.1%

.5%

Total (3-6yrs)

47

85.5%

13.2%

1.3%


No adverse or side effect seen.

Change in mean PD and CAL of pocket initially 1-3mm

Years

No. Patient

No. Of sites

Pretreat

(mm)

Post treat

(mm)

Reduction

(mm)

Mean CAL gain

3-4

17

722

2.38

2.54

-.16+-.03

-.54+-.05

4-5

14

675

2.52

2.50

.02+-.03

-.32+-.04

5-6.5

16

733

2.43

2.57

-.14+-.03

-.56+-.05

total

47

2130

2.44

2.54

-.10+-.03

-.48+-.03

 

Change in mean PD and CAL of pocket initially 4-6mm

Years

No. Patient

No. Of sites

Pretreat

(mm)

Post treat

(mm)

Reduction

(mm)

Mean CAL gain

3-4

17

407

4.88

3.92

.96+-.05

.42+-.07

4-5

14

350

4.80

3.80

1.00+-.06

.55+-.06

5-6.5

16

375

4.93

3.74

1.19+-.06

.68+-.07

total

47

1132

4.87

3.83

1.04+-.03

.54+-.04

 

Change in mean PD and CAL of pocket initially >=7mm

Years

No. Patient

No. Of sites

Pretreat

(mm)

Post treat

(mm)

Reduction

(mm)

Mean CAL gain

3-4

17

132

8.01

5.36

2.65+-.13

1.70+-.14

4-5

14

86

8.29

5.01

3.28+-.20

2.36+-.22

5-6.5

16

137

7.81

4.62

3.19+-.14

2.06+-.17

total

47

355

8.00

4.99

3.01+-.09

2.23+-.10

 The antimicrobial treatment regimen appeared to halt successfully the progressive, destructive disease activity in ten patients with refractory periodontal conditions who had responded poorly to the conventional mechanical/surgical therapy they had received earlier.
Sustained suppression of disease associated microscopic morphotypes with nonsurgical treatment modalities may be difficult to attain in advanced periodontal sites without adjunctive systemic antibiotic therapy.
Doses of NaHCO3, NaCl, MgSO4, and Chloramine T were introduced repeatedly into periodontal pockets at therapeutically significant levels known to be bactericidal to many suspected periodontopathic microorganism.
Patient with advanced periodontitis can be treated and maintained successfully on a long term basis without periodontal surgery when appropriate antimicrobial therapeutic interventions are targeted against the subgingival disease associated bacterial flora.

Comparative study between conventional regimen and Keyes regimen
Larry Wolf et al. 1989. Four year investigation of salt and peroxide regimen compared with conventional oral hygiene.

171 subjects divided into two groups: conventional OH (n=87) and salt and peroxide regimen (n=84). Salt and peroxide regimen: 3 drop of hydrogen peroxide and 3 drop of water and sodium bicarbonate for brushing, and saturated solution of sodium chloride for irrigating.
Duration: 48 months (4 yrs).
Parameters measured: Plaque index of Silness and Loe, GI of Loe and Silness, PD, CAL, compliance and acceptance of treatment survey.
Data collection: 8, 16, 24, and 48 months.
Protocol: base line data record, perio instrumentation, data record at interval specified, acceptance and compliance measured at 24 and 48 months.

Result:
1. Both regimens, when combined with professional care, were effective in changing clinical measures of periodontal disease to a state favoring periodontal health. No statistical difference were detected between each oral hygiene regimen at each time point.
2. 80% like the conventional regimen, thus a higher level of compliance and acceptance in the conventional.
3. Higher percentage of salt peroxide regimen experience irritation within their mouth at 24 months.

Effect of Keyes method of oral hygiene on the subgingival microflora compared to the effect of scaling and/or surgery.
(Greenwell, Bakr, Bissada, Debanne, Rowland, 1985).

There is no statistically difference between the Keyes method of oral hygiene and conventional oral hygiene in patients treated with single session of SCRP. When scaling was not employed, Keyes method was more effective than conventional oral hygiene. Surgery was most effective in reducing clinical indicators and established control of subgingival microflora. Oral hygiene alone had only a minimal effects on subgingival microbial proportions. SCRP produced a shift in subgingival morphotype proportion, and this effect was enhanced with surgical access and debridement.

Salt and Peroxide compared with conventional oral hygiene. I. Clinical results
(Bruce Pihlstrom, Larry Wolff, Bakdash, Schaffer, Jensen, Aeppli, and Bandt, 1986)
Four treatment regimens was compared: conventional oral hygiene(soft toothbrush, sensodyne paste, and floss), conventional OH and phase contrast demonstration, Salt/Peroxide oral hygiene, Salt/Peroxide oral hygiene plus phase contrast demonstration.
The result indicated that both conventional oral hygiene procedure and the salt peroxide regimen were effective in reducing clinical sign of disease when combined with professional care. There were no differences between the two regimens in clinical effectiveness and trends favoring microscopic viewing of subgingival plaque for motivational purposes were not statistically significant.

Salt and Peroxide compared with conventional oral hygiene. II. Microbial results
(Bruce Pihlstrom, Larry Wolff, Bakdash, Schaffer, Jensen, Aeppli, and Bandt, 1986)
For both hygiene group, cocci were increased and motile rods were decreased at 8 months and returned to baseline by 16 months. Spirochetes were decreased and remained low through 24 months in both oral hygiene groups. There is only 59.8% agreement in clincal and microbial criteria for instrumentation. A significant change in microbial signs associated with periodontal disease may be obtained with either a conventional oral hygiene or a salt and peroxide oral hygiene home care regimen. There is no evidence that a home care salt peroxide OH regimen will contribute more toward periodontal health than use of a commercial toothpaste, toothbrush, and floss. Microbiological criteria lead to fewer instrumentation (15%) than clinical criteria (34%).
Salt and Peroxide compared with conventional oral hygiene. III. Patient compliance and acceptance (Bruce Pihlstrom, Larry Wolff, Bakdash, Schaffer, Jensen, Aeppli, and Bandt, 1986)
80% patient in the conventional group like their regimen as compared to only 57% like their salt/peroxide regimen. Viewing of the bacteria microscopically significantly contribute to the patient understanding of the periodontal conditions and motivate the patient to better oral hygiene. Inconvenience was cited by 23% of conventional and 43% of the Salt/peroxide group as reason for not using their regimen.

Counter view on the Keyes technique
I. Monitoring
Phase contrast microscopy will not be able to distinguished or identified the bacterial species thought to be periodontal pathogen but only allow description on size, shape, and motility. In fact, most of these species look microscopically like health associated species. This is true with A.A. associated with early onset form of periodontitis such as JP and RPP. Microscopic monitoring does not discriminate among the pathogens that are associated with the early onset form of periodontitis.
The Keyes technique only give relative quantitative information of the bacterial appearance in a plaque mass. Thus plaque maturation plays a major role on deciding whether or not the organism will be present. In the case of gingivitis and AP, it is likely that many bacterial pathogen are not present until later stages of plaque maturation. Available current technology such as nucleic acid and antibody probe is the much better tool to assess specific bacterial population.

Advantage of microscopic monitoring: (AAP)
1. establish the bacterial etiology in periodontal disease
2. Assessing plaque control effectively in some types of periodontal disease
3. Useful patient motivational tool
4. Additional therapeutic endpoints can be emphasized beyond current clinical parameters.

Disadvantage: (AAP)
1. Does not assess the majority of suspected bacterial pathogen in perio dz.
2. Very sensitive to the quality of the equipment and expertise of user. Technique sensitive lead to frequent occurence of false negative result.
3. Cannot identified the most aggressive forms of periodontal disease such as the early onset periodontitis and RPP.
4. Does not have an added diagnostic value over conventional technique for assessment of disease or monitoring of the progress of a case.

II. Treatment: Local therapy
Advantage:
Emphasis on importance of conventional periodontal therapy of local cleaning and
patient home care.
Disadvantage:
1. Patient energies in home care are directed toward oral hygiene practices that do not give added value over conventional techniques and abuse of the practices may lead to gingival injury. (AAP)
2. Poor compliance due to complexity of the regimen (salt/peroxide/baking soda) (Larry Wolf et al., 1989)
3. Short exposure to sodium bicarbonate or sodium chloride had no effect on bacterial survival (Nicholas Amigoni, et al., 1987) The release of oxygen in the presence of catalase and peroxidase by hydrogen peroxide is short lived and the presence of the organic matter decreases the effect. Sodium bicarbonate-hydrogen peroxide and salt water did not provide additional benefits to scaling and conventional home care procedures.
4. Study done on effects of sodium bicarbonate and hydrogen peroxide on the microbial flora of 4-7 mm pockets revealed no unusual benefits in reducing microbial flora of periodontal pocket. No statistical significant difference in the change of microflora and motility of organism were found between medicament (sodium bicarbonate and 3% H2O2) and control (fluoride paste brushing) (splitmouth design). (Margaret B. Cerra and William Killoy, 1982)
5. Intensive oral hygiene efforts without thorough scaling and root planing may yield a significant reduction of gingival inflammation and mask an underlying submarginal gingivitis. (Greenwell et al., 1983)
6. Hydrogen peroxide can produce superoxide radicals and reacts with other superoxide radicals to form hydroxyl radicals, which in turn can cause chromatid exchanges in mammalian cells and neoplastic changes.( Weitberg, et al, 1983).
7. ADA council on dental therapeutics has stated that hydrogen peroxide should not be used as mouth wash for long period because of the concern that its acid may cause tooth decalcification.
8. Sodium bicarbonate can cause desquamative gingival lesions in some patients.

III. Treatment: systemic antibiotics
a. In a well controlled studies, the use of systemic antibiotics alone or in conjunction with local therapy have shown of limited or no added value over local therapy in the treatment of adult periodontitis.
b. Bacterial resistance-Tetracycline significantly increase the number of bacteria resistnat to multiple important antibiotics.
c. Poor indication: poor plaque control and/or indadequate SCRP lead to bacterial persistence in AP cases. Systemic antibiotic prescribed in this case will produce a very transient and limited antimicrobial effect.
d. May be recommended for the more aggressive form of the disease; however, these forms were not identified by the Keyes technique.
e. Potential drug interaction of Tetracycline HCl.


Drug interactions of tetracyclines
Tetracyclines: Potentiates anticoagulant effects
Potentiates toxicity of lithium
Potentiate vasoconstrictive effects of ergot alkaloids
Potentiates nephrotoxicity of diuretics (especially in elderly or dehydrated
patients)
Decreases bacteriocidal effects of penicillins and ciprofloxacin.
Digestive absorption inhibited by antacids, antianemics, magnesium
containing drugs and milk products.


Is antibiotic therapy justified in the treatment of human chronic inflammatory periodontal disease?
1. Generally, in adult periodontitis, patient with undetermined disease activity, systemic antibiotics often do not seem to offer long term improvement in clincal status. (Slot and Rams, 1990).
2. Adult with periodontitis can successfully be treated by scaling and root planing, followed by plaque control during the maintenance phase. Access to the root surfaces can be facilitated by surgical procedures. Antibiotic treatment as an adjunt to scaling and root planing, applied systemically or topically by slow release device, has not been shown to offer advantages, possibly with the exception of adjunctive metronidazole treatment which may have some benefit, but the data from clinical trials with metranidazole are conflicting. (Helderman, 1986)
3. The use of antibiotics in the treatment of periodontal disease has failed with regard to the concept of suppressing suspected periodontal pathogen. So far, antibiotics have been used as a supplement to the nonspecific approach of root debridement by scaling and root planing and it can be doubted whether the antibiotic approach offers any benefits at all. (Helderman, 1986).
4. Today, with new research in host response modifiers in the treatment of Periodontal disease, the use of Periostat (doxycycline hyclate 20mg) may be instituted in those individual with known systemic compromised individual (diabetics and immunocompromised patient). The human studies have demonstrated the inibition of collagen degradation by subantimicrobial doses of doxycycline at a dose of 20mg twice daily, can have a significant benefit in enhancing the effects of scaling and root planing in patients with chronic periodontitis. (Caton, Ciancio SG, Blieden TM, et al., J Periodontology 2000;71(4):521-532)