|Year : 2019 | Volume
| Issue : 5 | Page : 274-279
An update on the relative vulnerability of the first and second permanent molars to caries in urban Nigerians
Odogun A Loto1, Afolabi Oyapero2, Adenike O Awotile1, Olugbenga A Adenuga-Taiwo1, Lillian L Enone3, Ifeoma N Menakaya1
1 Department of Restorative Dentistry, Lagos State University College of Medicine, Ikeja, Lagos, Nigeria
2 Department of Preventive Dentistry, Lagos State University College of Medicine, Ikeja, Lagos, Nigeria
3 Department of Restorative Dentistry, Lagos State University Teaching Hospital, Ikeja, Lagos, Nigeria
|Date of Web Publication||24-Sep-2019|
Dr. Afolabi Oyapero
Department of Preventive Dentistry, Lagos State University College of Medicine, Ikeja 21266, Lagos.
Source of Support: None, Conflict of Interest: None
Aims and Objectives: Caries is a dynamic disease from an interaction between environmental, behavioral, and genetic elements. We aimed to determine if the changing dietary patterns of urban Nigerians have any effect on the relative susceptibility of the first and second permanent molars to caries. Materials and Methods: The case files of 7977 patients, who attended the Restorative Clinic at the Lagos State University Teaching Hospital Dental Centre, from 2012 to 2015, were reviewed for the occurrence of caries. Differences in the levels of occurrence of caries between the first and second permanent molars, with regard to age, gender, and the mandible and maxilla, were established by means of chi-square test, and the level of significance was determined at P ≤ 0.05. Results: The second permanent molars were more susceptible to caries at 4013 (58.8%) compared to first permanent molars at 3448 (46.2%). A higher proportion of second permanent molars were decayed or filled (3146, 42.2%) compared to that of the first molar (2348, 31.5%) (P< 0.001). However, a greater number of first molars (1100, 14.7%) were extracted due to caries compared to second molars (887, 11.6%). Males had more carious lesions (4422, 59.3%) compared to females (3039, 40.7%) (P > 0.05). The number of carious first and second molars was higher in the lower jaw (4498, 60.3%) compared to the upper jaw (2963, 39.7%) and the difference was statistically significant (P < 0.001). Conclusion: The second permanent molars were more vulnerable to caries indicating apparent changing dietary patterns of urban Nigerians. Further prospective studies, covering a wider age range, should be carried out to validate or refute the claim of this study.
Keywords: Caries Vulnerability, Dental Caries, First Molar, Patterns of Tooth Decay, Second, Molar
|How to cite this article:|
Loto OA, Oyapero A, Awotile AO, Adenuga-Taiwo OA, Enone LL, Menakaya IN. An update on the relative vulnerability of the first and second permanent molars to caries in urban Nigerians. J Int Oral Health 2019;11:274-9
|How to cite this URL:|
Loto OA, Oyapero A, Awotile AO, Adenuga-Taiwo OA, Enone LL, Menakaya IN. An update on the relative vulnerability of the first and second permanent molars to caries in urban Nigerians. J Int Oral Health [serial online] 2019 [cited 2021 Dec 3];11:274-9. Available from: https://www.jioh.org/text.asp?2019/11/5/274/267720
| Introduction|| |
Most oral diseases are progressive with cumulative effects, and they have lifelong consequences on quality of life. Dental caries, which is the primary reason for tooth mortality in both industrialized and emerging market countries, is a sugar-dependent infectious disease, caused by demineralization of the tooth surface as a result of the acid of metabolism of dietary carbohydrates by plaque bacteria. Caries is thus a dynamic process characterized by episodic demineralization and remineralization occurring over time. Dental caries is still a key health challenge in most developed countries because it affects 60%–90% of school-aged children and a high proportion of adults. Children’s performance in school and their success in life can be affected due to poor oral health, and caries also has an impact on their nutritional status.
Dental caries is more prevalent in several Asian and Latin American countries than that in most African countries. The mean number of decayed, missing, and filled teeth (DMFT) of 12-year olds in most of the developing countries has been reported to be less than two. A high proportion of caries in developing countries, however remain untreated and are subsequently extracted. Unrestored caries in permanent teeth was reported by Marcenes et al. as the most widespread health disorder the world over, whereas untreated caries in deciduous teeth was the 10th most common ailment in the Global Burden of Disease Study conducted in 2010. In contrast, caries experience has been on the decline in several Western countries, possibly due to the use of fluoride containing toothpaste, fluoridation of drinkable water and improved oral hygiene, widespread use of fissure sealants, and enhanced oral health education.
Irrespective of prevalence values for caries in different countries, it has been observed that different tooth surfaces have variable vulnerability to dental caries attack, and this may also vary among populations and different age groups. The pattern of distribution of dental caries usually follows a specific pattern signifying that different tooth surfaces have dissimilarities in caries vulnerability. Variation in the caries susceptibility should be considered when preventive strategies for caries control are designed after risk assessment. Many research have been carried out on the prevalence of caries with specific reference to the first and second permanent molars.,,,,,,,,,,, In a comparative study of relative susceptibility of first and second permanent molars to caries in urban Nigerians by Akpata and Jackson in 1978, the most vulnerable permanent molar teeth to caries were the second permanent molars. In similar studies in Uganda, Tanzania, Zambia, South Africa, and Botswana, it was reported that the vulnerability of second permanent molars to caries was greater than the first permanent molars.,,,,, This was contrary to what had been reported in the Western world and Asian countries where the first permanent molars were found to be the most vulnerable teeth to caries.,,,,
In a more recent article, Akpata reported that caries, as an oral disease, is still a major public health problem in Nigeria, in the face of changing dietary patterns of Nigerians, dwindling financial fortunes, and infrastructural collapse in the health sector. As no recent study has explored the differences in susceptibility to caries between the first and second molar, the aim of this study was to assess the relative vulnerability of the first and second permanent molars to caries attack with a view to ascertaining any change in the previously established pattern of caries involving the two tooth types in the light of changing dietary patterns of Nigerians in recent times.
| Materials and Methods|| |
This was a retrospective and descriptive study on the relative susceptibility of the first and second permanent molars to caries attack using the dental records and case histories of patients. The study was performed at the clinical unit of the Faculty of Dentistry, Lagos State University College of Medicine, Lagos State University Teaching Hospital (LASUTH), Oba Akinjobi Road GRA Ikeja, Lagos State, Nigeria. The procedure for this study was presented to the Health Research and Ethics Committee, LASUTH, and written approval was acquired (LREC. 06/10/1163). In this study, 7977 case files of patients who attended the Restorative Clinic at the Dental Centre, LASUTH, Ikeja, Lagos, between 2012 and 2015, were reviewed, and only 2266 case files met the inclusion criteria. A formal written request, which was approved, was also obtained from the medical records department of LASUTH. Written informed consent was not obtained because the data were collected anonymously from the patients’ records and their confidentiality was guaranteed.
The inclusion criteria were (1) male and female subjects between 18 and 65 years with carious first and second permanent molars, (2) missing first and second permanent molars extracted due to caries as well as those replaced with fixed or removable prostheses, and (3) restored first and second permanent molars. The exclusion criteria included (1) case files with incomplete information with respect to age and gender of the subjects and the indications for previous extraction and (2) filled, missing, or replaced first and second permanent molars not due to caries.
The principal investigator and a second examiner were calibrated for data collection using some randomly selected dental records of patients at the oral diagnosis unit of the dental center. Inter-examiner reliability for both examiners was 0.92, whereas the inter-examiner reliability was 0.93 and 0.89 for the two examiners, respectively. The paper and electronic dental records of the patients were subsequently extracted by the dental record officers after they were given the written permission from the medical records department and the principal investigator obtained the date of birth, gender, the diagnosis of dental caries was made by the dental surgeon, pattern and distribution of the carious teeth in the mandible and maxilla, treatment plan, and the treatment details such as restorations and/or extractions of the patients. The chart review process was repeated by the other calibrated examiner and the data were compared for reproducibility and consistency. Other parameters such as socioeconomic status, religion, and occupation were not considered during the review of the patients’ case files.
Statistical analysis: Data were inputted and analyzed using the Statistical Package for the Social Sciences (SPSS) software, version 20 (IBM, Armonk, New York). Descriptive statistics was used to quantify variables such as age, gender, and carious teeth. Chi-square test was used to determine the relationship between categorical variables and as a means of comparing any variation in the vulnerability of the first and second permanent molars to caries attack. The confidence and significant levels for statistical analysis were set at 95% and 5% (P ≤ 0.05), respectively.
| Results|| |
With respect to the permanent molars reviewed in this study, 7451 decayed, missing, and filled first and second molars were recorded in 2266 case files of male and female patients. The highest proportions of respondents were aged between 28 and 38 years (601, 26.5%), whereas the least number of respondents were aged between 80 and 89 years (11, 0.5%). Overall, there were more males (1414, 62.4%) than females (852, 37.6%). There was a bimodal clustering of male subjects with a high prevalence of carious lesions in two age groups, 18–27 years (342, 15.1%) and 28–38 years (360, 15.9%), whereas the modal distribution of female subjects with the highest number of carious lesions was in the 28–38 years age group (241, 24.1%). The age group and gender distribution is presented in [Table 1].
The prevalence of carious teeth showed that second permanent molars were more susceptible to caries at (4013, 58.8%) compared to that of first permanent molars at (3448, 46.2%). A greater number of second permanent molars were decayed or filled (3146, 42.2%) because of caries compared to the first molar (2348, 31.5%) and the difference was statistically significant (P < 0.001). Thus, most of the cavitated dentine lesions and filled teeth due to dental caries recorded were in the second permanent molar. However, a greater number of first molars (1100, 14.7%) were missing (extracted due to caries) compared to second molars (887, 11.6%). From the dental records, teeth that had pulpal involvement, dentoalveolar abscess, became retained roots, and had to be extracted due to caries were found to be more prevalent in first than that in the second permanent molars [Table 2].
|Table 2: Prevalence of caries in first and second molar teeth based on gender, decayed/filled, missing, and jaw quadrants|
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The mandible (60.3%) was more affected than the maxilla (39.7%). A greater number of carious lesions involving both first and second molar was observed in males (4422, 59.3%) compared to females (3039, 40.7%), although the difference was not statistically significant (P> 0.05). The number of carious first and second permanent molars in the right sides of both jaws (3814, 52.1%) was higher than the left sides of both jaws (3647, 48.9%), and the difference was statistically significant (P < 0.001) The number of carious first and second molars was higher in the mandible (4498, 60.3%) compared to that in the maxilla (2963, 39.7%) and the difference was statistically significant (P < 0.001) [Table 2].
| Discussion|| |
The epidemiology of dental caries has been widely studied,,,,,,,,,,,, but there is always need for further research because of the changing patterns of the disease with respect to its incidence, geographical spread, gender and age distribution, socioeconomic factors, and treatment plans in addition to the financial burden that it has on the health system. This need for unceasing research is imperative to develop plans and strategies for the prevention of dental diseases, identification of vulnerable groups, and tooth types as well as modification of existing treatment modalities.
Our primary outcome variable was the dental caries susceptibility of the first and second molar teeth, and this was identified by the DMFT due to dental caries as observed in the dental records of the patients. The main predictor variables were the age and gender of the respondents. The key finding of this study was the observation of a greater vulnerability of second permanent molars to caries compared with that of first permanent molars. The results of our study further validate the findings of a previous Nigerian study conducted by Akpata and Jackson and other similar African and Indian studies carried out in Uganda, Tanzania, Zambia, South Africa, and Botswana.,,,,, The period of eruption of second permanent molars, which are adjudged to be immature at this period corresponds to period of increased cariogenic challenge. Therefore, second permanent molars are more prone to caries attack than the first permanent molars, which had matured over 6 years before the eruption of the second permanent molars. Therefore, the pattern of greater vulnerability of second permanent molars to caries compared to first permanent molars, established by the previous study of Akpata and Jackson was confirmed by this study.
In contrast to our observation, a study conducted by Stenlund et al. validated the findings of previous studies that the first permanent molar had a higher susceptibility to caries than the second permanent molar. Similarly, Umesi-Koleoso conducted a study on the vulnerability of first and second permanent molars to caries on 600 secondary school students (aged 11–16 years) in Lagos and found that the first permanent molars were more prone to caries compared to second permanent molars. She concluded that a change in lifestyle and diet toward consumption of refined sugars might be responsible for this shift. The difference between our study and Umesi-Koleoso could be explained on the basis of the difference in sample sizes and the age brackets of the sampled patients in these compared studies. Our study was conducted on a sample of 2226 patients aged 18–89 years, whereas former studied on 600 school children aged 11–16 years. It should be noted that caries is a time-dependent disease, which increases with age up until 28–30 years when its rate of occurrence begins to slow down.,,
The secondary findings of this study were that most of the cavitated dentinal carious lesions and filled teeth due to dental caries recorded were in the second permanent molar. However, a greater number of first molars were missing (extracted due to caries) compared to second molars. Thus, teeth that had pulpal involvement, dentoalveolar abscess, became retained roots, and had to be extracted due to caries were found to be more prevalent in the first than that in the second permanent molars. The first molar takes a longer time to be in full eruption of its crown and it is exposed to an accumulation of dental plaque much longer, due to its length of stay in the mouth, hence carious first molars tend to be extracted more often if care is not sought.
We also secondarily observed that the lower first and second permanent molars were more susceptible to caries compared to upper first and second permanent molars. This finding was consistent with previous epidemiological studies.,,, The greater occurrence of caries involving permanent molars in the mandible compared to that in the maxilla has been attributed to greater number and deeper fissures, groves, and pits on lower permanent molars as well as force of gravity, which enhance greater accumulation of biofilm on permanent molars in the mandible compared to that in the maxilla. We furthermore observed that the upper and lower right first and second permanent molars were more prone to caries compared to upper and lower left first and second molars. This finding was also consistent with the previous epidemiological studies.,,,, The preponderance of caries of first and second permanent molars on the right sides of maxilla and mandible over the left sides of both jaws has been attributed to the tendency of people to chew on the left side more than the right side as well as more consideration being given to the left sides of the mandible and maxilla during prophylactic procedures. The most frequently used sides of the jaws, which might also enjoy greater attention during prophylactic procedures, have been found to accumulate less biofilm owing to shearing forces of masticatory processes and tooth brushing.,
In addition, we observed in our study that males appeared to be more susceptible to dental caries than females. This finding was akin to some previous epidemiological studies., However, some studies have shown greater caries affection in females than that in males., The greater caries experience of males compared to females in our own study may be ascribed to a better awareness of oral hygiene, more visits to the dentists, and aesthetic consciousness on the part of females compared to that of males., The most affected age group was 28–38 years and this was consistent with previous studies, which had shown that caries experience increased with age until early middle age when it would begin to slow down.,,
The strength of our investigation lies in our large sample size and that it is one of the few Nigerian studies of this kind, which had a broad age distribution. This investigation, however, had a number of limitations. We recognize that these results are based on a group of hospital patients possibly with a high caries risk rather than in the general population, hence the results many not be generalizable for the whole population. The study design was also of retrospective and descriptive nature, and this investigation did not provide explanation of other factors that could affect relative susceptibility such as exposure to fluoride, access to dental care, oral hygiene habits, diet, education, income, and lifestyle. However, within the limits of the design of this study, the data still provide useful information for further exploratory study. This information obtained about the pattern of caries susceptibility of permanent molars among Nigerians can aid in the design of strategies for prevention and treatment. Thus, the inclusion of recommended preventive measures in the most susceptible groups of sites should result in a considerable caries reduction. On the basis of our data, the immediate implication of our research is that sealant placement, which is strongly recommended in the high-risk populations, is highly indicated on second molars in Nigerians. We also propose that regular screening should be carried out for patients in their second and third decade in addition to that, which is usually carried out for children and that every opportunity should be sought to incorporate oral health education into every preventive program.
Lastly, the scope of our study was simply to assess the influence of age and gender differences in dental caries susceptibility of molars without determining the specific factors responsible for these differences. Thus, additional research is needed to identify the factors contributing to these disparities. Therefore, additional exploration is necessary to elucidate these factors through a longitudinal cohort study rather than a retrospective study design. In addition, the World Health Organization measures of tooth decay such as DMFT and decayed missing filled surfaces indices may not detect the whole spectrum of the caries process from incipient, arrested, non-cavitated, and cavitated lesions. DMFT is also not optimal for studying genetic and environmental influences that affect the patterns of caries across the dentition. Thus, in addition to the DMFT, the International Caries Detection and Assessment System, the significant caries index, and the Pulp, Ulceration, Fistula, Abscess index will be used in these longitudinal studies.
Study showed that the second permanent molars were more susceptible to caries attack than the first permanent molars in urban Nigerians even in the face of apparent changing dietary patterns of urban Nigerians toward western diets. It is suggested that a wide age range of subjects, say 5–65 years, should be studied prospectively so as to reconfirm or refute the claim of this study. The clinical significance of this finding is that a selective use of pits and fissure sealants should be considered on permanent second molars as it is being carried out on first permanent molars so as to reduce the vulnerability, morbidity, and mortality of second permanent molars.
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Conflicts of interests
There are no conflicts of interest.
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[Table 1], [Table 2]