Antibacterial efficacy and effect of Morinda citrifolia L. mixed with irreversible hydrocolloid for dental impressions: A randomized controlled trial.

AIM: This study aimed to evaluate whether the extract of Morinda citrifolia L. mixed with irreversible hydrocolloid powder decreases microbial contamination during impression making without affecting the resulting casts.
MATERIALS AND METHODS: Twenty volunteers were randomly divided into two groups (n = 10). Group A 30 ml extract of M. citrifolia L diluted in 30 ml of water was mixed to make the impression with irreversible hydrocolloid material. Group B 30 ml deionized water was mixed with irreversible hydrocolloid material to make the impressions following which the surface roughness and dimensional stability of casts were evaluated.
RESULTS: Extract of M. citrifolia L. mixed with irreversible hydrocolloid decreased the percentage of microorganisms when compared with water (P < 0.001) but did not affect the surface quality or dimensional stability of the casts.
CONCLUSION: Mixing the extract of M. citrifolia L. with irreversible hydrocolloid powder is an alternative method to prevent contamination without sacrificing impression quality.

RCT Entities:   Population Interventions Outcomes

The use of irreversible hydrocolloid has been the material of choice for making dental impressions. These impressions are disinfected either by spraying the disinfectant or by immersing the impression into the disinfectants.[1] Although these techniques have appreciable results on the impression surface; however there is an uncertainty regarding the presence of the microorganisms inside the body of the impressions.[2] Plants have always been among the common sources of medicines, either processed as traditional preparations or used to extract active principles. The large chemical diversity of secondary plant metabolites, which are mostly targeted to animal physiology, makes it a promising source for new therapeutic candidates for a great variety of diseases.

Morinda citrifolia L. (noni) is a common traditional medicinal plant of the native people of the South Pacific, who used all parts of the plant for the treatment of a broad variety of diseases, including gingivitis.[3456] In the last 15 years, various in vitro and in vivo investigations have been done about the biological activity of noni. In many situations, a juice prepared from ripe noni fruits was used for these investigations. Surrounded by various positive effects on health, current research results declare that noni juice has, antifungal effects,[7] antibacterial effects,[89] anti-inflammatory effects,[1011] immune enhancements,[1213] and analgesic effects.[14] The incorporation of this M. citrifolia L. extract into dental impressions may provide an alternative method for preventing contamination of impressions. Therefore, the aim of the study was to evaluate whether the extract of M. citrifolia L. mixed with irreversible hydrocolloid decreased the percentage of microorganisms when compared with water without affecting the accuracy of the resulting cast. The null hypothesis was that the addition of M. citrifolia L. would produce no significant differences regarding microbial contamination or dimensional accuracy of the resulting cast.

Materials and Methods

The following clinical study was performed as a triple-blinded inclusive of the patient, the operator and the microbiologist and a completely randomized design. The study was performed according to the CONSORT statement. The volunteers were assessed for oral health. Sample size calculation (n = 8) was performed using Mann–Whitney test with the study power of 80% (α =5%).[15] Twenty volunteers were selected for the study.

The patients were divided randomly into two different groups (n-10) based on the type of liquid used with the irreversible hydrocolloid, using a computer-generated random number table. Standard proportion based on the manufacturer instructions irreversible hydrocolloid was mixed either with deionized distilled water or 30 ml extract of M. citrifolia L diluted with 30 ml of water. The sequence of the treatment was concealed in sealed envelopes.

Samples of saliva were collected before and after impression making. Preferably maxillary impressions were made, and a piece was cut from the palatal area with 10 mm diameter and 2 mm thickness. Each sample was inoculated on specific media and was incubated at 37°C for 24–96 h. The colony forming units were counted and assessed as the percentage reduction of microorganisms following which the measurements were done by a blind examiner under the same condition.

The dimensional stability of the resultant cast was assessed using a metal master template containing two circular columns on a platform, which was used as control. Impressions were poured using type-4 gypsum products. The distance between the inner and the outer pillars of the casts were compared to the control using a digital caliper. The change in the surface roughness was evaluated using a profilometer (Surfcorder SE 1700 Kozaka industry, Kozaka, Tokyo, Japan) mean value of five readings was made, and the differences were evaluated.

The various microorganism counts, dimensional stability and the surface roughness (P < 0.05) was analyzed using Mann–Whitney U-test, two-way analysis of variance and Student–Newman-Keuls test.

Results

The impressions of irreversible hydrocolloid mixed with the extract of M. citrifolia L. [Table 1] showed less microorganisms in total (P < 0.001), Candida species (P = 0.10), and streptococcoi counts (P = 0.001). The samples of saliva which were taken after impression making with extract of M. citrifolia L in comparison with deionized distilled water were considerably less contaminated (P = 0.001). The surface characteristics and the dimensional stability of the resultant cast showed no statistically significant differences [Table 2].

Table 1

Mean (SD) counts of total microorganisms (total Streptococci and Candida colony forming units)

Table 2

Mean (SD), surface roughness (Ra, μm), and dimensional stability (mm)

Discussion

The study showed that there was a decrease in the total percentage of microorganisms in the irreversible hydrocolloid impressions made using the extract of M. citrifolia L in comparison with the impressions made using deionized distilled water. There was no change in the dimensional accuracy and the surface characteristics of the resultant cast, which were made following the impression with the extract of M. citrifolia L. Therefore, the null hypothesis was rejected. It should be noted that M. citrifolia L have already been proven to have antifungal[7] and antibacterial effects;[89] hence, when this was used with the impression material it showed to prove its ability to act on the microorganisms, which could cause contamination with no differences in dimensions and surface characteristics of the resultant casts. However, the cost of the extract of M. citrifolia L is expensive in comparison with deionized distilled water but the disinfection benefits of the extract, which was observed is worth the increased cost.

The concentration of the extract of M. citrifolia L used in the present study is equal to the concentration which is used to treat gingivitis/periodontitis[15] and adding on to the additional benefits of using this extract allows internal disinfection of the impression as well.

Conclusion

The use of the extract of M. citrifolia L with the irreversible hydrocolloid to make dental impressions proved to decrease the contamination of microorganisms with no negative changes on the resultant cast their by preventing any cross-contamination.