Tserakhava T.N., Chernjavskaja N.D. The eruption of the first permanent molars in children in Minsk / Tserehava T.N., Chernjavskaja N.D. // 8 Kongres Stomatologa Vojvodine. Zbornik Radova, Novi Sad, Serbija 13-14 Maj 2017. – Novi Sad, 2016. – P. 79-81.

The eruption of the first permanent molars in children in Minsk Tserakhava T.N., Chernjavskaja N.D. Belarusian State Medical University, Department of Pediatric Dentistry, Minsk, Belarus

Introduction. Eruption of permanent teeth is one of the indicators of physiological development of the child. Dental caries is the most common dental disease among adults as well as children [2]. The first permanent molars soon after eruption are affected by caries, because hard tissues of the tooth at that time are immature and have low resistance to decay [1,2]. To speed up the mineralization of hard tissues of these teeth and prevent caries various methods of medical prevention are used. Implementation of preventive measures right after teething improves their efficiency [3]. According to the literature, the first permanent molars appear in children aged 5-7 years (Schroeder 1991, R. Kronfeld, W.H.G.Logan) [3,4]. However, information about the timing of the eruption of the first permanent molars in children accommodated in the Republic of Belarus are absent in the scientific literature. The aim of the study. To examine the terms of eruption of the first permanent molars in children aged 5-7 years. Materials and methods. To achieve the goal a dental examination of 220 children aged 5 to 7 years was held. The children were divided into three groups: I group consisted of 50 children (26 girls and 24 boys) at the age of 5 years, II group - 50 children (22 boys and 28 girls) 6 years of age; III group - 120 children (63 boys and 57 girls) aged 7 years. The survey was conducted in the dental office with a set of dental instruments (Dental probe, mirror). We used conventional methods of examination of dental patients. Survey data was recorded in the modified WHO map. Results of the study. The study found that in the mouth of 41out of 50 five-year old examined children (82 ± 3,84%) all of the first permanent molars were missing. So, tooth 1.6 was detected in 8,0 ± 3,84% of children, tooth 2.6 - at 4,0 ± 2,77% and teeth 3.6 and 4.6 - in 12,0 ± 4,59% and 14.0 ± 4 91% of children, respectively (table 1). Only two (4,0 ± 2,77%) of all children in this age group had all four first permanent molars erupted. There were no statistically significant differences in the frequency of eruption of the first permanent molars depending on the quadrant (p> 0.05) and gender of the five-year olds (χ² = 1,5; p1> 0,05; χ² = 0,1; p2> 0, 05; χ² = 1,0, p3> 0,05; χ² = 1,8, P4>

0.05). Table 1.- Frequency of eruption of the first permanent molars in children aged 5-7 years living in Minsk

Age Number Frequency of eruption of teeth: of kids 1.6 2.6 3.6 4.6

abs % abs % abs % abs %

5 50 4 8,0 ±3,8 2 4,0 ±2,8 6 12,0± 4,6 7 14,0±4,9

6 50 40 80,0±5,7 38 76,0±6,0 44 88,0± 4,6 43 84,0 ± 5,2

7 120 112 93,3±2,3 111 92,5±2,5 117 97,5± 1,6 115 95,8± 1,9

In a study of six – year old children, the presence of the first permanent molars in the mouth in most children was registered (43 persons or 86,0 ± 4,9%), which indicates an active dentition. 80,0 ± 5,7% 6-year olds had tooth 1.6, 76,0 ± 6,0% - tooth 2.6, 88,0 ± 4,6% - tooth 3.6 and 84,0 ± 5,2% - tooth 4.6. Only in 7 patients (2 males and 5 females), which amounted to 14,0 ± 4,9% of the number of examinees no permanent molars were observed in the oral cavity. There were no statistically significant differences in the frequency of eruption of the first permanent molars, depending on quadrant (p> 0.05) and gender of 6-year olds (χ² = 1,0; p1> 0,05; χ² = 0, p2> 0.05; χ² = 1,4, p3> 0,05; χ² = 3,78, P4> 0.05). Statistically significant was more frequent presence of the first permanent molars in all quadrants of 6-year olds compared to the five-year old children (χ² = 52,6, p1 <0,001; χ² = 54,0, p2 <0,001; χ² = 57,8, p3 <0,001; χ² = 49.0, P4 <0.001). At the age of 7 years, only 3 (2,50 ± 1,42%) kids did not have any of the first permanent molars in their dentition. In children at seven years of age first permanent molars erupted as follows: 1.6 tooth - in 93,3 ± 2,3%, 2.6 tooth - in 92,5 ± 2,5%, 3.6 tooth - in 97,5 ± 1,6% and a tooth 4.6 - at 95,8 ± 1,9% of children. Statistically significant differences in the frequency of eruption of the first permanent molars, depending on the quadrant (p> 0.05) in seven-year old children were not established, but the teeth 2.6 and 4.6. statistically significant were more likely to erupt in girls than in boys (χ² = 5,2, p1 <0,05; χ² = 4,7, p2 <0.05). In addition, significant more likely was the presence of the first permanent molars in all quadrants in children at seven years of age compared to the five-year old kids (χ² = 118,6, p1 <0,001; χ² = 124,0, p2 <0,001; χ² = 129,0, p3 < 0,001; χ² = 116,6, P4 <0.001) and a six-year old children (χ² = 6,6, p1 <0,01; χ² = 8,6, p2 <0,01; χ² = 6,4, p3 <0.01 ; χ² = 7,1, P4 <0.01). Conclusion Thus, the results of the study showed that the eruption of the first permanent molars in children begins at the age of 5 years, actively continues at the age of six and is almost completed by the age of seven.

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