Oral presentation in the 25 Congress of the UNAS, Bucharest, october 2021
Abstract
There are few studies about eruption and caries experience of premolars in children and adolescents.Material and method. Cross-sectional retrospective observational study using dental files of patients aged 9 to 17 years examined and treated in Pedodontics Department during 2009-2020.Eruption status of premolars according to age and sex was assessed and their dental health statusaccording to age, sex, topography and severity of lesions was analyzed.Results. a)262 patients (134 boys) (mean age=13.13±2.48 years); b) at the age of 9, about 40% of patients had at least one firstpremolars erruptedand 7% – at least one of second PMs; c) 39.31% of children had caries lesions on at least one premolars (39.55% – boys, 39.84% – girls; NS, p>0.05); d) the percentage of children with decayed premolars raised from 12.5% at the age of 9 to 73.91 % at the age of 17; e) caries experience indices: DMF-TPM=0.95, DMF-SPM=1.29. Conclusions. 1)At the age of 9 about 1/3 of patients had already first premolars erupted and about 10% had at least one second premolar erupted; 2) The caries prevalence on premolars was high, especially on upper premolars, uncomplicated caries on one surface occured even at the age of 9; 3) It is necessary to supervise the eruption sequence of premolars and to detect those with caries vulnerability in order to early apply the local methods for caries prevention.
Key-words: eruption, caries experience, premolars, children, adolescents
Introduction
Premolars, by their eruption in the area of curvature of the dental arch, play a role both in establishing of proper occlusal relationship and in masticatory process [1].
Over the years, numerous studies have analyzed the chronology and sequence of the permanent teeth eruption according to a number of parameters, including sex of the individual, ethnicity, geographical localization etc. and pointed out that in the canine-premolar segment there are the largest variations [2]. In addition, the premolars eruption is also influenced by local factors, such as complicated caries of primary molars, their early loss leading to the space reduction, leading to the malpositions of the successors and favoring the dental crowding [3, 4].
Regarding the caries experience of premolars, it is known that their crown morphology with deep pits and fissures that favor plaque retention, as well as the immaturity of enamel in the first years after eruption lead to an increased caries vulnerability in children and adolescents [2]. Also, untreated caries in primary molars can have a long-term negative impact on successorstrough the possibility of occurence of structure abnormalities in premolars, areas with a high risk of caries attack [3]. Complicated caries in premolars are often followed by the gross destruction of the hard tissues, which can tead to their fracture and subsequent loss of the arch [5].
Given these aspects, the aim of the present study was to analyze the eruption sequence and carious experience in premolars in a group of children and adolescents aged 9 to 17 years.
Material and method
The research was performed ona sample of children and adolescents examined and treated in the Pedodontics Department, Faculty of Dentistry, Carol Davila University, Bucharest during 2009-2020. The inclusion criteria were: patients of Caucasian origin, clinically healthy, without any genetic syndrome, aged 9 to 17 years.
A cross-sectional retrospective study was performed, using dental files of patients examined and treated by one dentist (AM). Data about premolars eruption and their status (caries-free, decayed, filled or loss due to caries) at the moment of first dental visit were noted from the dental files. Age of eruption for upper and lower premolars was assessed acording to age and sex, and dental health status was assessed according to patient’ age and sex and topography and severity of the caries lesions.
Statistical analysis of data obtained was performed using SPSS 20.0 for Windows (SPSS Inc., Chicago, IL, SUA), at a level of statistical significance set at p=0.05.
Results
The study sample comprised 262 patients (134 boys) (mean age=13.13±2.48 years) (fig.1).
1) Age of premolars’ eruption
Regarding first premolars, at the age of 9 it was observed that approximately 40%of children had at least one of upper first premolars present on arch. In both boys and girls, in the 9-11 age group, the percentage of upper first premolars present on the arch was higher than the percentage of lower first premolars.
Regarding the second premolars, some of them were already erupted in the arch at the age of 9 in 7% of patients, and from the age of 11 in about 60% of patients.
In both girls and boys, all upper first premolars were found to be present in the arch at the age of 13, and upper second premolars and lower first premolars at the age of 14. Very small differences between the two sexes were noticed in the case of lower second premolars, all of them being erupted in girls at the age of 15 and in boys at the age of 16(table I).
2) Dental health status of premolars
39.31% of the examined children had caries on at least one of the premolars, the prevalence being 39.55% in boys and 39.84% in girls, with no statistically significant differences (p>0.05).Compared to each age group, the percentage of children with decayed premolars increased from 12.5% at the age of 9 at 73.91 % at the age of 17.
Regarding the first premolars, 30.91% of the children from the study sample had caries on at least one of them, the prevalence being 34.32% in boys and 28.12% in girls. Analyzing by age groups, the percentage of children with caries on the first premolars increased from 9% at the age of 9 to 61% at the age of 17.
Regarding the second premolars, 26.71% of children already had caries lesions on at least one of second premolars. The caries prevalence indexin this tooth was 22.38% in boys and 27.24% in girls. By age groups, the percentage of children with caries on second premolars ranged from 3% at the age of 9 at 27% at the age of 17 (table II).
3) Distribution of caries lesions
In both boys and girls, upper premolars were more vulnerable to caries atack than their lower counterparts, with a upper:lower ratio of 1.8:1 (table III).
Related to midline, the percentage of caries damage on the left side was slightly higher (15.53% compared to 14.75%), with a left:right ratio of 1.05:1, but the diferences were not statistically significant (p>0.05).
Regarding the severity of carious lesions, it was noticed that the uncomplicated caries were diagnosed from the age of 9 for both first and second premolars, and the complicated caries – in a much smaller number from the age of 11 for second premolar and from the age of 12 for the first premolar. The most common uncomplicated caries affected a single surface – the occlusal one (tab. IV).
Related to age, the distribution of uncomplicated and complicated caries was in an exponential growth trend for the 9-14 age group, reaching the maximum value at the age of 17 (fig. 2).
4) Caries experience indices
Caries experience indices on premolars represent about 20% of the value of these indices for all permanent teeth (table V).
Analyzing the caries damage of premolars according to the presence of untreated caries on first permanent molar, it was found that 48.5% of patients with untreated caries on first permanent molars also had decayed premolars. In contrast, only 11.29% of patients with treated caries on first permanent molars had decayed premolars.
Discussions
The age of eruption of permanent teeth is an indicator of the physiological development of a child. The sequence and chronology of toot eruption are influenced by various physiological factors (eg: sex, race, regional differences, climate, socio-economic factors, urban/rural environment) or pathological – general (eg: genetic or endocrin diseases) or local (obstacles in the eruption path, lack of space) [2, 6].
Knowledge about the mean age of tooth eruption are useful to establish a correct diagnosis, to make an orthodontic treatment plan at the most favorable moment and to apply preventive therapeutic measures against the caries lesions evolution [1]. It is important to note that the primary molars pathology can influence the development and eruption of the premolars.
The phenomenon of permanent tooth eruption has been studied by many researchers, and the conclusion was that the canine-premolar segment has large variations in the sequence and chronology of eruption, which are differentiated by arches and sex [1, 2]. In the study sample it was noticed that premolars were aldready erupted on the arch from the age of 9 (in 30-40% of children for first premolars and in 3-7% for secondpremolars). For both sexes, in the 9-11 age group, the percentage of the first premolars erupted on the maxilla was higher than in the mandible. This is not the case with the second premolars, where there were greater variations in the age of the eruption depending on age and sex.
The study performed by Nassif et al. (2020) on a sample of 2317 children from Lebanon identified the eruption of first premolars from the age of 9-10 years and the eruption of second premolars from the age of 10. They have also reported that, for both sexes, premolars erupted first in the mandible, symmetrically for both hemiarches of a jaw [7]. Comparatively, in the study by Waghmode et al. (2020), the eruption of first premolar was noticed even from the age of 8 and the eruption of the second premolar from the age of 9, first in the mandible and in females [8]. In our country, in a study conducted on a sample of 2081 children from Bucharest aged 8 to 13 years, Feraru et al. (2011) found that premolars erupt between 9.55 years (lower first premolar in girls) and 11.15 ani (lower second premolar in girls) and that the first premolars erupt earlier in both archesin girls[9]. In addition, the study conducted by Munteanu et al. (2019) on a sample of 655 children aged 9 to 14 yearsreported that 32.86% of children aged 9 and 45.68% of children aged 10 already had at least one second premolar erupted on the arch [10]. Moslemi (2004) found that the mean age of eruption of permanent teeth, except for upper second premolars, was lower in girls compared to boys. It was also reported that there was a greater range of variability in second premolars in girls and in first premolars in boys [11]. Rajic et al. (2000) showed that premolar eruption was observed a little earlier in girls than in boys [6].
Regarding the dental health status, 30.91% of children aged 9 to 17 of our sample already had caries on at least one of the first premolars and 26.71% on at least one of second premolars. Caries prevalence was higher in boys for first premolars (34.32% versus 28.12%) and in girls for the second premolars (27.24% versus 22.38%). However, taking into account the impairment of both first and second premolars, although the prevalence value was higher in girls (39.84%) than in boys (39.55%), the differences were not statistcalyy significant (p>0.05).
Numerous studies on caries prevalence have been performed special to first permanent molars. Although premolars occupy the second place, after molars, in the mastication process, less atention has been paid to the study of caries frequency at this level. As a percentage of caries damage to molars and premolars, Akpata and Jackson (1978) showed that out of a total of 1031 decayed permanent teeth, only 13.77% were premolars and 81.66% were molars [12]. Strictly related to premolars involvement, in a retrospective study performed on 655 patients aged 9 to 14 years (mean age=11.62±1.61 years), Munteanu et al. (2019) found that 31.28% of patients had caries on second premolars, with no statistically significant differences between the two sexes [10].Crown morphology of premolars (pits and fissures that favor plaque retention), incomplete enamel maturity in the first years after eruption, especially in case of early eruption and co-existence with decayed primary teeth make premolars more vulnerable to acid attack. In these teeth a very important aspect is that once complicated caries occur, if the proper and complete treatment is not performed quickly, often by prosthetic methods, there is a risk of crown-root fractures, with early loss of the arch. Thus, a study conducted by Ion et al. (2019) showed that in a sample of 147 young patients, aged 18 to 35(mean age=27.01±5.09 years), who were examined in two private dental offices, 27.67% had upper first premolars extracted, 18.75% – upper second premolar, 7.87% – lower second premolar and 3.14% – lower first premolar [13].
From the point of view of caries topography, our study showed a predominant damage of upper premolars (maxilla:mandible ratio of 1.8:1), with a symmetrical left-right distribution (ratio 1.05:1). Out the total of 262 children analyzed, 81 had caries on first premolars and 70 on second premolars (ratio 1.15:1). Our results are partially confirmed by the study conducted by Loto (1998) on a sample of patients aged 16 to 60. This study showed that the upper premolars are twices as vulnerable to caries attack as their lower counterparts (maxilla: mandibleratio of 2.4:1) and that, in term of symmetry of distribution on hemiarches, there is a right:left ratio of 1.24:1. In contrast, in these subjects with the mean age of 25 years, much older than in our study, carious lesions were more frequent in second premolars than in first premolars (ratio of 1.6:1) [14]. As in out study, Demirci et al. (2010) found that the occurence of caries lesions was higher in maxilla (62.4%) than the mandible (37.6%) (maxilla:mandible ratio of 1.6:1) and that sex din not influence the caries prevalence in analyzed teeth [15].
Following the analysis of the caries distribution according to age, in both premolars it was observat that the percentage increased from 11 to 14 years (from 9% at the age of 9 to 50% at the age of 14 for first premolars and from 2% at the age of 9 to 44% at the age of 14 for second premolars). Hence the importance that should be given to preventive dental treatments, especially fissure sealing. The high degree of tooth decay vulnerability in the first two years after the eruption is known. It is likely that the adolescent will perform a superficial brushing on the erupted teeth, due to gingival bleeding and discomfort, and the mastication will be performed unilaterally (on the opposite side of the tooth eruption). In this way, the tooth is prone to the accumulation of microbial plaque, followed in a short time by the onset of carious lesions, which could explain the existence of tooth decay in barely erupted teeth [5, 14]. Fissure sealing as close as possible to the moment of the eruption can reduce the risk of carious lesions. This is supported by numerous studies, which show the increased effectiveness of sealants in preventing caries in pits and fissures in both dentition, even with a 70% reduction [16, 17].An argument for the establishment as soon as possible of local prevention methods (eg: sealants, applications of fluoride varnishes) is brought in our study by the finding that in the age group 9-11 years, with very rare exceptions, the most common caries were located on a single surface, usually on the occlusal surface, and caries on two or three surfaces and complicated caries apearing after the age of 11.
Adolescence, which is representative of premolar eruption, is marked by an increase in the prevalence of tooth decay. For example, NHANES (National Health and Nutrition Survey) studyconducted in SUA in 1999-2004 showed that the prevalence of caries increased from 10.16% in children aged 6 to 8 ani to 36% at the age group 9-11 years, reaching at 51% in adolescents aged 15 years [18]. This fact is supported by the present study, where the mean value of DMF-Tindex in children aged 9 to 17 yearswas 4.82 and about 20% of this value was given by premolar damage. Similar results were presented in the study by Eslamipour et al. (2010), where the mean avalue of DMF-Tindex for permanent teeth at the age of 11-17 was 4 [19].
Conclusions
- At the age of 9 about 1/3 of patients had already first premolars erupted and about 10% had at least one second premolar erupted;
- The caries prevalence on premolars was high, especially on upper premolars, uncomplicated caries on one surface occured even at the age of 9;
- It is necessary to supervise the eruption sequence of premolars and to detect those with caries vulnerability in order to timely apply the local methods for caries prevention.
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