Clinical and Laboratory Grounds for the Rational Selection of Filling Material for the Restoration of Deciduous Teeth

Objective: To compare the use of two different restorative materials placed in deciduous teeth. Material and Methods: Clinical observations were formed in the number of 58 patients aged 3 to 12 years; 23 with deciduous dentition, 35 with mixed dentition. The total number of teeth was 266. The Index of destruction of the occlusal surface of the teeth (IROPZ) and the following materials were used: Ionofil Molar® (VOCO) and Twinky Star® (VOCO). Microphotographs of the sections selected for illustration were performed using a Biorex-3 VM-500T microscope with a digital DCM900 attached photo element using for interpretation of the results adapted data research software. The Spearman correlation coefficient [r] was used to examine the relationship between the parameters evaluated. The level of significance was set at 5%. Results: The Twinky Star® compomer has been found to be optimal for restoring the teeth with an IROPZ of less than 0.55, pH levels of <6.2 and any values of the degree of acidity of the enamel [r = 0.89]. Ionofil Molar® showed to be a material of choice with high and average degrees of acidity of the enamel [r = 0.65]. Conclusion: Choice and usage of different types of restorative materials depend on the period of bite, the condition of root formation, group membership of the teeth, depth and topography of the carious, the level of the pH of the saliva, the degree of acid resistance enamels and areas of destruction of the occlusive surface of the tooth.


Introduction
The prevalence of caries in deciduous teeth remains at a very high level, despite the considerable selection of restorative materials and the great interest of researchers to this problem.It is important to remind that the countries of Eastern Europe belong to the regions that has biogeochemical deficit of the essential elements, the balance of which during the period of laying, forming, mineralization and growth of deciduous teeth is extremely important [1][2][3][4][5][6][7][8].
In the conducted epidemiological studies among the children of the Transcarpathian region, it has been established that the prevalence of caries in deciduous teeth is 98.3% at an intensity of 14.9 [9,10].In the situation when we face absence of a General Nationwide Program for the prevention of caries among Ukrainian children, the most effective method is the individual approach in each case.A pediatric dentistry is the only one who contributes to the preservation of the health of children's teeth.
Today, there is a huge arsenal of dental materials for the restoration of primary teeth, indications and contraindications to their use are clearly defined by the firm manufacturers.
However, when choosing the restorative material for effective and long-term recovery, it is necessary to take into account a wide range of local and general factors, that are to be taken in consideration, to apply an during individual approach.
According with the literature, the cause of reoccurrence of patients after 24 months with primary diagnosis of caries of deciduous teeth in 41.7% cases the loss of the filling and in 20.8% cases the filling defect were mentioned as the key problems [11].This indicates a violation of the treatment protocol conduction and an ineffective selection of restorative material [12].
The choice of material for recovery in the treatment of caries among children is an extremely responsible and difficult task for the dentist.In modern literary sources, a large amount of information can be found on how restorative materials are interacting with tooth tissues, which of them have sufficient adhesion to enamel and dentin, how effective they are, their positive or negative influences on tooth tissues.But it is often difficult for a doctor to choose the best material for recovery in a specific clinical case.Therefore, the aim of the study is to compare the use of two different restorative materials placed in deciduous teeth.

Material and Methods
For the in-depth analysis of the criteria for the selection of restorative materials, a clinical target observation groups were formed in the number of 58 patients aged 3 to 12 years; 23 patients with a deciduous dentition, and 35 patients with mixed dentition.The total number of teeth taken for analysis was 266, among them the temporary teeth in the stage of stabilization of the root was performed 138 teeth, in the stage of resorption of the root -128 teeth (Table 1).
For the purpose of determining the optimal efficiency of the use of restorative materials, the following filling materials were used for analysis: glass ionomer cement Ionofil Molar ® (VOCO, Cuxhaven, Germany) and the Twinky Star ® compomer material (VOCO, Cuxhaven, Germany).Among the parameters to be analyzed, optimization of the choice of the restorative material were: the condition of the root formation, the group membership of the tooth, the depth and topography of the carious cavity, the level of the pH of the saliva, the degree of acidity of the enamel, taking into account the types of adhesion of the restorative materials to the hard tissues of the tooth.
Indicators are ranked as follows: 10 points -indicates the expediency of using this material with this criterion, 0 points -with this parameter the material is not recommended.The destruction index of the occlusal surface of the teeth (IROPZ) was determined according to the method proposed.
By the area of destruction of the occlusive surface, the teeth were randomized into 2 groups: a) Teeth that were damaged less than 0.55 by the index of IROPZ and b) those that were damaged or destroyed on more than 0.55 by the index of IROPZ.
The natural level of oral pH was determined using a strip-test (pH 6.2 is critical).To determine the caries resistance of the enamel of the teeth, a test of enamel resistance was performed (TER-test) [13].
In order to unify the criteria for the selection of restorative materials, a complex histological and histochemical research was carried out on aiming to detect the state of hard tissues of temporary teeth that were removed by orthodontic and surgical indications on the basis of the University dental clinic of the State Higher Educational Institution "Uzhhorod National University (Ukraine).
Histological examination of solid teeth was carried out on thick and thin slabs, in the manufacture of which, orienting on protruding and in-depth anatomical formation of occlusal surface, which gave the possibility of comprehensive and detailed morphological analysis of tissues.As a marker, the SHIK alcyanic blue was used to identify the enamel (blue) and dentin (red), since altium blue, due to the presence of copper salts in its composition, is fixed only on the surface of enamel prisms, which makes it possible to detail the surface picture.A line of adhesion of the material to tooth hard tissues was visualized using a polychrome dye (1% solution of methylene blue and 0.1% solution of toluidine blue) method by [14,15].
Microphotographs of the sections selected for illustration were performed using a Biorex-3 VM-500T microscope with a digital DCM-900 attached photo element using for interpretation of the results adapted data research software.

Statistical Analysis
The Spearman correlation coefficient [r] was used to examine the relationship between the parameters evaluated.The level of significance was set at 5% [16].The value of the correlation coefficient characterizes the degree of dependence between the values to the linear functional, which corresponds to the value r ± 1 of the correlation coefficient.If rxy> 0, then the correlation is positive.This means that with the growth of one of the values, the second -also, on average, increases.In the case where rxy <0, the correlation is negative.In this case, with the growth of one of the variables, the second -on average, decreases.In the absence of a statistical relationship between the values, the correlation coefficient is zero.
The calculation of prognostic coefficients for each criteria was performed using mathematically processing the obtained values -method using Bayes formula.

Results
During the examination, the topography of the tooth damage was determined; defect presence within the enamel and dentine edge was diagnosed on 87 teeth, within the cloak dentin -137 teeth, and on the level around the pulp dentin -42 teeth (Table 2).The total number of those damaged by less than 0.55 was 191 teeth.The number of teeth that were damaged by more than 0.55 on the IROPZ index was 75 teeth.3).

Discussion
The saliva provides "maturation" of the enamel and forms the special properties of its surface layer.Thus, the period of "ripening" of enamel after teething is most important in the formation of their caries resistance or caries-susceptibility.Research showed that tooth resistance to tooth decay depends largely on properties of enamel and saliva [17,18].Particularly important in the period of mineralization of permanent teeth by children are the salivation rate, the characteristics of the mineral composition (calcium, phosphorus content), solubility of the enamel and remineralizing ability of saliva.Therefore, these indicators can be considered as a single system of mineralization of hard tissues of the tooth.
As a result of the complex clinical and morphological investigation of the properties of the restorative materials and their subsequent statistical justification, it has been established: the Twinky Star ® compomer is highly effective for use in the deciduous dentition of the chewing and frontal groups (10 points), regardless of the state of root formation (10 points), in the treatment of middle and deep caries (10 points), with the value of IROPZ> 0.55 (0 points), it is not appropriate to use the material.The degree of acidity of the enamel (10 points) does not affect the use of this material.
Adhesive properties are optimal for both enamel and dentin (10 points) [19].Also, the bite period and the peculiarities of the histological organization of dental tissues, topography and depth of damage, as well as the area of damage, were taken into account.The restoration of defects in the coronary part in the clinic was preceded by an experimental substantiation of the criteria for choosing a material for restoration.To this end, we studied the nature of the adhesion of the restorative materials to the hard tissues of the teeth by means of laboratory tests using selected materials, namely Ionofil Molar ® and the Twinky Star ® compomer.
Since the results of many writers indicate that the relationship between pH parameter 12-14 in the period of deciduous and mixed dentition, this parameter should be taken into account when choosing a restorative material.This parameter is entered into the parameters selected for the correlation analysis.

Conclusion
The Twinky Star ® compomer material is optimal for restoring the decidous teeth of any group.For the treatment of both acute and chronic, and middle and deep caries of temporary molars, irrespective of the state of root formation, at any values of the level of the pH of the oral fluid, with high and medium degrees of acidity of the enamel, it is recommended to restore glass ionomer cement Ionofil Molar ® .When restoring the chewing surfaces of the molars, despite the condition of the root, the depth of lesions by the carious process, the nature of the course of the caries and the degrees of acidity of the enamel, at pH> 6.2, it is recommended to use the Twinky Star ® compomer material.
reduced structural and functional resistance of the enamel and the maximum risk of caries and 4-6 points were noted in 59 (22.2%) cases.Such an indicator shows the average structural and functional resistance of the enamel and the average tooth strength to caries.The indicator in 1-3 points was noted in 41 (15.4%) cases.Such an indicator suggests that there is a significant structural and functional resistance of the enamel and high tooth firmness to tooth decay (Table Glass ionomer cement Ionofil Molar ® is expedient to use for the restorative manipulations with caries cavities of deciduous teeth of chewing group (10 points) with unformed (5.6 points) and mold (4.4 points) roots, for the treatment of middle and deep (10 points), taking into account the area of destruction of the occlusal surface up to 30% (5 points), irrespective to the level of the oral pH (10 points) with high (10 points) and average (8 points) degrees of acidity of the enamel (Figure1).

Figure 1 .
Figure 1.Gradation scale of indicators of optimal filling materials usage among children with deciduous dentition.