Titanium and its alloys are the most widely used biomedical materials for the manufacture of dental implants and prosthetic devices because of their physicochemical properties, in particular good corrosion resistance and biocompatibility [1] [2] [3]. Its high resistance to corrosion is due to its passivation layer, which has chemical stability allowing it to be protected in contact with fluids in the oral cavity [4] [5] [6] [7].

The oral cavity is a chemically aggressive environment for materials; the pH value varies continuously depending on the food, the presence of dental plaque or the acidity of the stomach [8]. Only electrochemical corrosion occurs in the living environment, it results from the reaction exerted by a reagent on a material [8] [9].

Metal ions released in the oral cavity diffuse: in hard tissues (bones, teeth), in soft tissues, in fluids (saliva through the digestive tract, blood by diffusion in the body) on cathodic metal (tarnishing). The local and general effects in the body correspond to the action of the released metals [8] [10].

The presence of microorganisms in the oral cavity influences the corrosive behavior of titanium dental implants; it tends to reduce the corrosion resistance of titanium dental implants [11]. Some authors report that eating habits are among the determinants of certain cardiovascular pathologies [12] [13]. In 2007 and 2015, toxicity and allergy to titanium were also reported by some authors [14] [15].

With the aim of preventing, if necessary, certain pathologies which could be linked to the presence of titanium in the body are devoted to the study of the reactivity of titanium dental implants in the salivary environment in the presence of certain foods usually consumed in our country and in the sub-region.

ICP-MS was used for the determination of traces of titanium in liquid samples.

The materials used in this study were:

- 24 test tubes with colored identification tablets;

- 24 solid titanium dental implant samples placed in test tubes with colored identification tablets containing artificial saliva in the presence of food for up to eight (08) weeks;

- Pharmaceutical artificial saliva (Artisial).

The foods used were:

- Lemon;

- The leaves of ground cassava and prepared with sodium bicarbonate (saka-saka);

- Salted fish.

Four (04) sets of experiments were performed over eight (08) weeks.

For each series, the test tubes were used with a numbering corresponding to each week. The titanium samples are removed from the solution at the end of each week. The following information was read from each test tube: the corresponding solution, the number corresponding to the week and the color assigned to the series of experiments (Table 1).

Cassava leaves (saka-saka) are prepared according to local habits, with sodium bicarbonate NaHCO₃ (sodium hydrogen carbonate) to keep its green color and to vary the taste.

We therefore obtained after eight (08) weeks a batch of twenty-four (24) liquid samples that we used to perform the analyzes, the search for traces of titanium in the liquid samples.

Before proceeding with analyzes, the samples were mineralized in a closed system in a microwave oven. About 0.25 g of the sample was used for mineralization 2 ml of 15% hydrogen peroxide and 1 ml of 65% nitric acid. After mineralization, the samples were diluted to 30 ml. Dilutions were made by weight. A small precipitate remained after mineralization; samples were filtered before analyzes.

An ICP-MS mass spectrometer was used to determine the content of titanium released after corrosion [16]. The calibration curve method with an external standard that had been prepared using 1% nitric (V) acid and a dental implant sample were used.

The procedural limit of determination for titanium using the ICP-MS technique is GO = 0.180 mg/kg.

In this work, we studied the corrosion of titanium dental implants in artificial saliva in the presence of certain foods (lemon, salted fish, cassava leaves ground and prepared with sodium bicarbonate).

The results obtained show extremely high corrosion with the leaves of ground cassava which is characterized by extremely high contents. We have noticed that the reactivity of titanium on salted fish is greater than that observed with lemon in artificial saliva. These results agree with those found by other authors.

In perspective, we will suggest a study on the correlation between the presence of titanium in the body and the state of health of the populations concerned.

The authors thank the center of biological and chemical sciences of the University of Warsaw for the use of their facilities for analyses by ICP-MS.

The authors declare no conflicts of interest regarding the publication of this paper.

Eboungabeka, A.D., Trigo, E.R.M.E. and Nsongo, T. (2021) Reactivity of Titanium Dental Implants in Salivary Environment in the Presence of Foods Consumed in the Republic of the Congo. Advances in Materials Physics and Chemistry, 11, 93-99. https://doi.org/10.4236/ampc.2021.115009