Clinical and Microbiological Efficacy of Pyrophosphate Containing Toothpaste: A Double-Blinded Placebo-Controlled Randomized Clinical Trial

(1) Background: Dental calculus works as a niche wherein pathogenic bacteria proliferate in the oral cavity. Previous studies revealed the anticalculus activity of pyrophosphates, however there was no clinical study that evaluated microbiome changes associated with calculus inhibition. Therefore, the aim of this randomized clinical trial was to evaluate the calculus inhibition of pyrophosphate-containing toothpaste and its effect on oral microbiome changes. (2) Methods: Eighty subjects with a calculus index ≥2 on the lingual of the mandibular anterior tooth were randomly allocated to the test group that pyrophosphate-containing toothpaste was given to or the placebo control group. Full mouth debridement and standardized tooth brushing instruction were given before the allocation. Plaque index, gingival index, calculus index, probing depth, and bleeding on probing were measured at the baseline, and at 4, 8 and 12 weeks. Genomic DNA was extracted from the plaque samples collected at the baseline and at 12 weeks, and 16S ribosomal RNA gene amplicon sequencing was applied for microbiome analysis. (3) Results: None of the clinical parameters showed significant differences by visits or groups, except the plaque index of the test group, which reduced significantly between 4 and 12 weeks. A significant difference of microbiome between the baseline and 12 weeks was observed in the test group. Between baseline and 12 weeks, the proportion of Spirochetes decreased in the control group, and the proportions of Proteobacteria, Fusobacteria and Spirochetes in the phylum level and the proportions of Haemophilus, Fusobacterium and Capnocytophaga in the genus level decreased in the test group. In the test group, as plaque index decreased, Streptococcus increased, and Fusobacterium and Haemophilus parainfluenza decreased. (4) Conclusion: The use of pyrophosphate-containing toothpaste effectively inhibited the dysbiosis of the oral microbiome and the proliferation of pathogenic species in periodontal disease. Clinically, plaque formation in the pyrophosphate-containing toothpaste group was effectively decreased, however there was no significant change in calculus deposition.

A randomized controlled clinical study of the effect of daily intake of Ascophyllum nodosum alga on calculus, plaque, and gingivitis

OBJECTIVE

The aim of this study is to evaluate, in a randomized controlled cross-over study, the effect of daily intake of the alga Ascophyllum nodosum on supragingival calculus, plaque formation, and gingival health over a 6-month period.

MATERIAL AND METHODS

Sixty-one adults with moderate to heavy calculus formation since their last yearly recall visit participated. In a randomized order over two 6-month periods, they swallowed two capsules daily, comprising a total of 500 mg dried marine alga powder (Ascophyllum nodosum, ProDen PlaqueOff®) or two negative control tablets. During the study, the participants maintained their regular oral habits. Their teeth were professionally cleaned at the start of each period and after the 6-month registrations. A wash out period of 1 month separated the two 6-month periods. Supragingival calculus (Volpe Manhold), gingivitis (Löe and Silness), gingival bleeding (Ainamo and Bay), and plaque (Quigley-Hein) were registered at screening and at the end of the two periods. Differences in oral health between the test and control periods were analyzed using a paired t test and Wilcoxon signed rank test.

RESULTS

Fifty-five participants completed the study. After the alga intake, the mean calculus reduction was 52% compared to the control (p < 0.0001). Fifty-two participants showed less calculus formation in the alga group than in the control group. Plaque (p = 0.008) and gingival bleeding (p = 0.02) were also significantly less in the alga group. However, no significant difference was found between the groups for gingivitis (p = 0.13).

CONCLUSIONS

The alga intake significantly reduced the formation of supragingival calculus and plaque and occurrence of gingival bleeding. The alga has a systemic effect on oral health.

CLINICAL RELEVANCE

Daily intake of the alga Ascophyllum nodosum as an adjunct to customary oral hygiene showed a major reduction of supragingival calculus formation and reduced plaque formation. In addition, the calculus in the alga group was characterized by a more porous and less solid structure and was easier to remove than the calculus in the control group.

Control of supragingival calculus. Scaling and polishing and anticalculus toothpastes: an opinion

The removal of supragingival calculus by scaling and polishing of the teeth is only one aspect of a dental prophylaxis. However in many countries, a large number of individuals only require and receive, at regular intervals, a supragingival scale and polish. The association of supragingival calculus to gingival and periodontal disease is unclear, however, it is logical to assume a plaque retention role. Moreover, for the individual, supragingival calculus may pose cosmetic problems. Regular calculus removal is both time consuming and exacting for dental professionals and has important financial implications to patients and/or health schemes. The benefits of regular supragingival calculus removal are not established, yet potential detrimental effects for the patient are known, and certain groups are susceptible to systemic disease consequent on scaling and polishing of the teeth. The oral hygiene habits of most individuals appear insufficient to prevent the reformation of supragingival calculus once removed and for this reason chemical inhibition is an attractive proposition. Most success to date has been with agents which inhibit crystal growth, notably pyrophosphates, and toothpaste products are available containing such agents. Clinical studies support efficacy for some products and indicate that the magnitude of calculus inhibition would reduce the need for or frequency of scaling and polishing of teeth in a proportion of individuals. Anticalculus toothpastes would appear to be proven worthy of recommendation for those individuals in whom supragingival calculus formation is a problem.

Evaluation of anti-calculus efficacy. An SEM method of evaluating the effectiveness of pyrophosphate dentifrice on calculus formation

A double-blind, cross-over study was carried out to assess the anti-calculus effectiveness of a pyrophosphate containing cleaning gel. 2 groups of 30 heavy calculus formers were followed up comparing conventional clinical scoring systems (Volpe-Manhold-Index and Marginal-Line-Calculus-Index) and micromorphologic SEM criteria of calculus formation and inhibition. The results indicated that after a 3-month period, there was a significant reduction of calculus formation compared to a placebo gel. The proposed SEM calculus index (SEMCI) objectively reflects the reduction of supragingival calculus formation.

Pyrophosphate inhibition of Proteus mirabilis-induced struvite crystallization in vitro

Struvite (MgNH4PO4.6H2O) crystals, the major mineral component of infectious urinary calculi, were produced in vitro by growth of a clinical isolate of Proteus mirabilis in artificial urine. P. mirabilis growth and urease-induced struvite production were monitored by phase contrast light microscopy and measurements of urease activity, pH, ammonia concentrations, turbidity, and culture viability. In the absence of pyrophosphate, struvite crystals appeared within 3-5 h due to the urease-induced elevation of pH and initially assumed a planar or 'X-shaped' crystal habit (morphology) characteristic of rapid growth. When pyrophosphate was present, initial precipitation and crystal appearance were significantly impaired and precipitates were largely amorphous. When crystals did appear (usually after 7 or 8 h) they were misshapen or octahedral in shape indicative of very slow growth. X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) identified all crystals as struvite. Trace contaminates of carbonate-apatite (Ca10(PO4)6CO3) or newberyite (MgHPO4.H2O) were produced only in the absence of pyrophosphate. P. mirabilis viability and culture pH elevation were unaffected by the addition of pyrophosphate, whereas urease activity and ammonia concentrations were marginally reduced. Struvite could also be produced chemically by titration of the artificial urine with NH4OH. If pyrophosphate was present during titration, the same inhibitory effect on crystal growth occurred, so it is unlikely that urease inhibition is important. Lowering of pyrophosphate concentration from 13-0.45 mumol/l did not reduce its inhibitory activity so it is unlikely to act by chelating free Mg2+. We propose that pyrophosphate inhibits struvite growth principally through direct interference with the chemical mechanisms involved in crystal nucleation and growth, because of its effectiveness at very low concentrations.

Report of Committee on Scientific Investigation of the American Academy of Restorative Dentistry

A few personal points seem appropriate in summary. It is axiomatic that while research solves problems, it also creates them. As an example, it is an accepted fact that dentistry more than any other profession has made serious inroads into putting itself out of business through research. Each year this report takes note of the reduction in dental caries in children, which has thus triggered a change in the nature of general practice. Be this as it may, it is well to acknowledge that major dental diseases are not disappearing, but their patterns in the population are changing, accompanied by an expansion of other services. Despite the optimistic picture painted earlier in this report, it is grossly premature to acclaim the elimination of caries, and thereby a significant segment of restorative dentistry. Of course the younger age groups have been the major beneficiaries of caries reduction. As the child ages from 9 to 16 years, the percentage of mouths free of caries drops by one half. In addition, the disease pattern in the adult population is being altered because of a longer life span and loss of fewer teeth. Unquestionably what we will, and are already seeing, is not an elimination of restorative dentistry but a different target and changes in procedures because of new materials, therapy, and expanded scope of services. There is yet another subtle change in the trend of dental research and it deals with the reduction in the number of dental schools worldwide and smaller class sizes in those schools. Dental research thereby suffers because of the traditional link between education and research. Thus the potential pool of researchers becomes smaller and research monies for training programs for dental investigators, particularly in clinical research, decreases. This year a surprising number of articles are concerned with manpower as it relates to research priorities. So, it is indeed a time that both the profession and the scientific community find filled with controversy and frustration. Yet never has there been a time that offers more in challenges and rewards.