Introduction

Tooth decay (dental caries) is a disease of multifactorial etiology. The essential factors include: the appropriate number and species of bacteria ,the type, quantity and frequency of consumption of fermentable carbohydrates, and susceptible tooth surfaces.(Loumans, etal; 1980) . Theoretically, tooth decay can be prevented by eliminating any one of these interacting factors. Water flouridation for example, has reduced caries by about (50%) without any additional therapeutic discipline. (yagot, 1981). The great deal of evidence has been accumulated which implicates Streptococcus mutans as a major etiological agent in the initiation of enamel caries.(Jagtap & Karkera, 2000; Hamilton & Svensater, 1998). It therefore seems reasonable that topical applications of chemotherapeutic agents may offer some promise for reducing the number of or completely eliminating Streptococcus mutans and perhaps other odontopathic bacteria from the infected tooth surfaces (Chen & Burne, 1996).Clinical studies have shown that teeth are most susceptible to tooth decay during the first 2 years after eruption. On the other hand, the greatest benefit of topical fluoride has been shown to occur in young persons who have newly erupted teeth and who reside in low fluoride areas (Tichy & Novak, 1998).

One of the most promising possibilities for the control of tooth decay involves the use of combined topical applications of fluoride with chemotherapeutic agents to increase the resistance of newly erupted teeth, enhance demineralization of hypomineralized enamel, and reduce microorganisms form infected teeth (Rupf, etal., 1999; Chen, etal., 1996).

This study aimed to evaluate antibacterial activity of extracts of Punica grantum (pomegranate) and comparison with various tooth pastes and commercial antibiotics against Streptococcus mutans on teeth surfaces with tooth decay.

Materials and Methods

Sampling and culturing

Antibacterial agents preparartions:

Tooth pastes :

Antibiotics:

Measuring of antibacterial activity:

Results

Form sixty samples of dental caries patients, the majority of bacterial types was for Streptococcus mutans which isolated from 79.3% of total sample, while other as follows:

E. coli 27.5%, Klebsiella 37.9%, Proteus 22.4%, Pseudomanas 41.3%, Stph. Aureus 17.2% and other Streptococcus spp. 51.7%. (Figure 1)

In Table (2) the mode of isolated bacterial types are shown, the biggest mode is for double pathogenes (34.48%), followed by third (27.58%), over than three pathogenes (24.13%), and single pathogene isolated from (13.79%) from total cases.

The total number of isolates is (161).

Table (3) summerized the results of antibacterial activity of plant extracts, tooth pastes, antibiotics determined by two methods Inhibition zone, MICs.

The nearest natural red pomegranate juice is effective more than the acidic and white natural and acidic white juice not effective.

The biggest diameter recorded for 1000 mcg/ml of fruit crust was (26 mm) than followed by other concentrations. Some of tooth pastes are not effective, however, in high concentration, but other such as signal-2 and close-up give 12,10 mm respectively of inhibition zones.

Concentration 100 mcg/ml of tooth pastes are not effective on growth of Streptococcus mutans .

In comparison – The standard antibiotics give the following inhibition zones:

16 mm of erythromycin, 10 mm of penicillin, 30 mm of vancomycin, 24 mm of cephalexin, 12 mm of tetracyclin and 22 mm of gentamycin.

The MICs for the plant extracts are as follow:

100-120 mcg/ml for pH 6.4 red juice and pH 6.2 white juice

200 mcg/ml for pH 4.6 red juice

400 mcg/ml for pH 4.3 white juice

80-90 mcg/ml for fruit crust

200-220 mcg/ml for signal-2 tooth paste

250-260 mcg/ml for close-up tooth paste

500 mcg/ml for sinan tooth paste

Figure 1

Table – 2: Infectious bacterial types isolated

Figure 2

Table (3): A comparison of susceptibility for antimicrobial agents, plant extract and antibiotics against isolated from dental caries

Discussion

Bacteria have been identified as the etiologic agents of many medically – important infections in man and animals.

Many studies demonstrated that teeth were demineralized when exposed to salivary bacteria and carbohydrates in vivo, he postulated that bacteria were the etiologic agents of dental caries, and rejected the concept that specific microorganisms could cause caries, holding instead that any and all of the acidogenic microorganisms in the mouth contributed to the process. Japtap & Karkera, 2000; (Rupf, et al., 1999)

Our results accompanied above study and results of other studies such as (Jagtap & Karkera, 2000; Schuber, et al., 1999; Chen & Burne, 1996) who evidenced that the Streptococcus mutans constitutes a majority of the total bacteria present in dental caries samples.

Other studies demonstrated that the initiation of a history of a previous Streptococcus mutans infection. In the absence of such a history, no caries occurred. The relationship of salivary concentration of Streptococcus mutans and the colonization of this microorganism on teeth has been studied in human, with an increase in Streptococcus mutans to levels of 5 X 10⁴ colony-forming units CFU / ml or higher most of the surfaces of the teeth were colonized (Rupf, et al., 1999).

The results of the present study revealed that pomegranate extracts- in especially- fruit crust extract is highly effective on growth of Streptococcus mutans in comparison with other extracts and various concentrations of tooth pastes, this fact may reflect efficiency of antibacterial activity of plant extracts, and ability of bacteria to resist other antibacterial agents such as pastes and antibiotics (Schubert, et al., 1999; Tichy & Novak, 1998).

Also these results may be correlated with the aspects involving the ecological balance and interaction of oral flora with the human host may appear to make prospects for chemotherapeutic management of dental caries a difficult task, and the mechanism of action of systemic fluorides not clearly understood.

Although clinical evidence suggested that at lest part of the action of systemic fluorides against caries must be a local action on or at the surface of erupted teeth (Yagot, 1981).

Conclusions & Recommendations

Streptococcus mutans constitutes a majority of the bacterial types associated with dental caries.

The high percentage of isolated more is for double mode (which yielded two bacterial types in same sample).

Studied tooth pastes give a lowest effects and some of it not effective on bacterial growth.

Plant extracts (pomegranate) varied in effects, the highest effect was for 1000 mcg/ml of fruit crust extract.

The limits of MICs for pomegranate extracts are between 80-400 mcg/ml and 200-500 mcg/ml for tooth paste concentrations.

The effects of plant extracts are within the range of effects of standard antibiotics studied in this investigation.

We conclude :

More care of oral cavity and teeth- in especially-.

Using a pomegranate extract or fruit crust after eating or before sleeping with combination to tooth paste.

Change the tooth paste in serial times within 2-3 months to prevent resistance of bacteria to tooth paste.