The Hormonal Fingerprints and BMI: Implications for Risk Factors in Dental Caries and Malocclusion

Abstract

IntrOductIOnMalocclusion is an appreciable deviation from the ideal occlusion and may be considered aesthetically unsatisfactory [1] thus implying a condition of imbalance in the relative sizes and position of teeth, facial bones and soft tissues (lips, cheek and tongue). Malocclusion is neither an unhealthy nor normal condition which occurs in most [2] as at this state the teeth stay firm, function efficiently, do not change the position during and after their contact, do not cause pain and remain in good state of health [3]. The hormonal fingerprint which is the ratio of second and fourth digit lengths (2D:4D) is a new risk marker that has been used in the study to predict caries risk at a very early stage of life is found to be more stable, reproducible and consistent for each individual. Research confirms the impact of hormones on human physical and personality traits. The second to fourth digit ratio (2D:4D) is sexually differentiated in humans [4] as for humans, men tend to have lower 2D:4D than women, this sex effect is due to men's greater relative length of the ring finger, in comparison with their index finger. The first mechanism explaining this sexual dimorphism is that the development of digits and gonads occur by the common genes Hox A and Hox D. The timing of gene regulation results in formation of a digit ratio which is constant throughout the life and also reflects the amount of androgen produced [5]. The second proposed mechanism is that finger ratio is a function of androgen sensitivity rather than androgen concentration. That is the two digit ratio affected by exposure to androgens e.g., testosterone while in the uterus, and that this 2D:4D ratio can be considered a crude measure for prenatal androgen exposure, with lower 2D:4D ratios pointing to higher prenatal androgen exposure [5]. These sex and individual differences in 2D:4D emerge in-utero at the beginning of the second trimester and seems to be fairly stable during postnatal life. This ratio will be helpful for assessing the action of prenatal sex hormone retrospectively on the brain, body and behaviour and for the prediction of malocclusion and caries risk for the individual [5].Obesity and childhood overweight are becoming a major public health concern all over the world. Sedentary life style and altered dietary patterns have led to the development of obesity. Obesity appears to influence the general health as well as the oral health of an individual. Obesity is considered as a major risk factor in increased prevalence of hypertension, type 2 diabetes mellitus, accelerates dental development and decreases masticatory performance. Diet which is one of the etiological factors along with obesity which also has an equal importance in the caries process. There are conflicting reports in the literature regarding the association between BMI and dental caries [6].

Prevalence of malocclusion in Chinese schoolchildren from 1991 to 2018: A systematic review and meta‐analysis

“…The pooled results of 16 included studies showed that males had a slightly higher prevalence than females, which was consistent with the results reported in some previous studies but contradictory to the results reported in other studies . The differences in the prevalence between genders observed in this study may be attributed to the latest finding that the rates of obesity and overweight are greater for males than for females in China, and obesity has been shown to be a risk factor for malocclusion . In addition, the sexual dimorphism in skeletal maturity might have contributed to the variations in the reported results.…”

“…14,47 The differences in the prevalence between genders observed in this study may be attributed to the latest finding that the rates of obesity and overweight are greater for males than for females in China, 48 and obesity F I G U R E 4 Forest plot of malocclusion in mixed dentition among different genders in mainland China during has been shown to be a risk factor for malocclusion. 49 In addition, the sexual dimorphism in skeletal maturity might have contributed to the variations in the reported results. Generally, pubertal growth spurts occur at 11.8 years of age in females and 13.8 years of age in males 50 ; therefore, females in the mixed dentition period are closer to their pubertal growth spurt than males.…”

Assessment of 2D:4D ratio for the early diagnosis of caries and malocclusion in 7-15-year-old children

“…In the present study, most of the participants had low 2D:4D ratio for both the hands. Similar results were shown by Priyanka GNDet al (2016) 4 where the authors' conducted the study to focus on the role of hormonal fingerprints in the early detection of malocclusion, caries, the influence of Body Mass Index (BMI) on caries and malocclusion along with identifying the association of BMI with 2D:4D ratio. Overall, 300 children from both sexes of age group 10 and 15 years were selected and digital vernier caliper was used for the measurements.…”

“…These dissimilarities in the digit ratios are established by the 13th or 14th week of intrauterine life (second trimester) and exhibit substantial constancy over the lifetime. 4 This ratiotends to vary among different ethnic groups, and surprisingly,this variation is far larger than differences between the sexes as shown in the study conducted by Manning et alwhere in addition to the significant sexual dimorphism in 2D:4D, the mean ratios varied between the English, Scottish, Uygur, Han and Jamaican children. 5 Objectives Hence, this paper was undertakento study the correlation between 2D:4D ratio and dental caries and malocclusion prevalence inNorthern Province of Saudi Arabia, to identify caries and malocclusion prone individuals, so as to facilitate the prevention of these problems.…”

Association of hormonal fingerprints and dental caries: A pilot study

“…[ 8 ] Further research to inspect the impact of 2D:4D on caries with larger sample size is required to ascertain the relationship with hormonal fingerprints and practical application in dentistry. [ 28 ]…”