Evaluating The Relationship Between Dermatoglyphics and Mandibular Third Molar Impaction - A Cross-Sectional study


 Introduction:

Dermatoglyphics may be of clinical significance to segregate those individuals who are at an increased risk for the presence of an impacted tooth. Dermatoglyphics seems to be promising as a non-invasive diagnostic tool to forecast the presence/absence of an impacted tooth.
Objective

The study aimed to analyze the most common pattern of dermatoglyphics present in an individual with/without impacted tooth and find a dermatoglyphic marker if any.
Methods

A cross-sectional study comprising of 180 subjects (90 cases and 90 control) was conducted. Blue duplicating ink was applied on the fingertips using the rolling impression technique and recorded.
Results

In individuals predisposed to the presence of impacted teeth, there was an increase in the frequency of WHORL-PLAIN pattern in right hand ring finger (60%) and left hand little finger (33.3%) with a p-value of 0.028 and 0.009 respectively, and LOOP-ULNAR in the right hand middle finger (74.4%) with a p-value of 0.024. Forward stepwise binary logistic regression analysis showed the left hand little finger to be the most predictive for impaction.
Conclusion

Dermatoglyphics could serve as a non-invasive marker to forecast the presence/absence of an impacted tooth. Its utility lies in early diagnosis to curtail the surgical complications associated with symptomatic removal of an impacted tooth.

Intrauterine incongruity such as foetus position, teratogens may in uence the developmental processes and also the ngerprint patterns. Therefore, dermatoglyphics can be a tool to detect any environmental insults during the development period of the foetus. Few studies have demonstrated the role of environmental factors in modifying the symmetry and size of the volar pads and subsequently affecting the dermatoglyphic pattern. [9] Like all physical features of the body, dermatoglyphic patterns are the product of an individual's genes and are transmitted to the offspring.
This was evidenced in a study conducted by Wieslaw Buchwald which concluded that a greater degree of morphological diversity was found in males, and on the ngers of the right hand in both the genders; and a statistically signi cant relation between parents and offspring, and between the siblings. [10] No two prints are identical and remain unchanged from one birth to the next. [11] Dermatoglyphic patterns are easy to record and interpret. Without much expense and paraphernalia, they can be recorded permanently. With the help of a forensic expert, they can be easily interpreted by using a magnifying lens. Overall, the total cost compares appreciatively with those of other investigation methods. [12] Dermatoglyphics can be used as a template to detect various diseases that are directly or indirectly in uenced by genes. [13] A study by Shapira Y et al con rmed that an autosomal genetic trait is linked to mandibular second molar impaction with a greater association in the Chinese American population. [14] Therefore, strengthening the genetic basis, dermatoglyphics can be implemented as a marker for the prediction of various disorders having a genetic predisposition.
The question, now, is to test the predictive possibilities of dermatoglyphics in search of the various inherited diseases known for their occult etiopathogenesis, decode the typographical skin carvings, and its inclination to certain diseases. This would augment preventive measures that would appear feasible to control morbidity and mortality at a larger scale.
Often impacted mandibular third molars are a causative factor to the development of distal caries, periodontal disease of mandibular second molar and hence need to extracted if they cause such issues. [1] Treatment of dental impaction sometimes becomes challenging for the clinicians due to a wide range of the cases encountered and complexity in the treatment. This necessitates the need for an investigation procedure that is quick, economic, and accurate. In concern to this, it would bene t clinicians to anticipate the presence of impaction and take measures at an early age.
There has been a relative dearth of research in the eld of dermatoglyphics which delves into the prediction of an individual towards the development of impaction. The present study was designed to analyze the most common pattern of dermatoglyphics present in an individual with an impacted tooth and nd a dermatoglyphic marker if any.

Materials And Method: Study Design
Comparative cross-sectional study

Study Settings
The study was carried out in the college premises. The duration of the study was 1.5 years with data collected using a study proforma sheet.

Study Population
Individuals greater than 20 years in age with/without impaction of tooth/teeth were the respondents for the study.

Inclusion And Exclusion Criteria:
Inclusion criteria: Individuals aged more than 20 years and willing to participate in the study were included in the study.
Exclusion criteria: Individuals who were differently-abled / had amputated forelimbs/scar on phalanges of hands/ having impacted tooth other than the third molars/ impacted third molar with pathology,were excluded from the study.

Sampling Procedure and Data Collection
The statistical formula was used to compute the sample size and a total of 180 participants were involved in the study, of which individuals with impacted third molar/ partially erupted third molar / missing third molars with no history of extraction were included in the case group comprising of 90 subjects; whereas individuals who had the full complement of erupted teeth (32 number) were taken as controls comprising of 90 subjects. The sampling technique used was quota sampling. Measures have been taken with interval matching. The participants were given the PATIENT INFORMATION SHEET [in Appendix] and the procedure was comprehensively explained in his/her vernacular language.
The ink method was used to record the impression of ngerprints with blue duplicating ink. The materials used were: Magnifying glass (5x), Cotton applicator, Soap, Water, Tissue paper, and study proforma sheet. [

in Appendix]
To ensure a good quality dermatoglyphic print, the hands of the participants were washed with soap and water followed by drying using tissue paper to remove sweat, oil, and dirt from the ngertips. Subsequently, a small daub of blue duplicating ink was applied on the cotton applicator and the ngertip was smeared evenly with a thin layer of ink. The rolling impression technique was preferred to record the impression on the study proforma sheet. This method enables to record complete imprints by rolling the nger from one side to the other (nail to nail). [15,16] To attain a high-quality impression, each digit was pressed rmly on the proforma sheet with stable and adequate pressure. To avoid duplication, blocks made on the proforma sheet were numbered from 1-5 for the right hand starting from thumb to the little nger and 6-10 for the left hand starting from the thumb to the little nger.
For participants with missing tooth/teeth without any history of surgery/extraction of the same, an Orthopantomogram (OPG) X-RAY [in Appendix] was taken to con rm the presence of impacted teeth or congenitally missing tooth/teeth Study Variables: Demographic variables were recorded. Impaction was taken as a dependant variable, along with that, all the versions of the ngerprints of all the ngers were taken as independent variables. All the ngerprints were taken as categorical variables which were divided iii. Plain-the wave in the centre is blunt/low in height iv. Tented-the wave in the centre is sharp/high in height [17] [ In Appendix ] Statistical analysis was done using SPSS 20.0 software at a 5% level of signi cance. The impaction with gender and the pattern of dermatoglyphics with each nger was compared using the chi-square test. The prediction of impaction was analyzed using forward stepwise binary regression analysis. Impaction was taken as the dependent variable and the patterns of each nger of the individual were taken as the independent variables for prediction.

Ethical Consideration
The clearance from the Ethics Committee of the institution (Ethical Clearance Reference number 18061) was taken before commencement. All the participants signed an Informed Consent Agreement [in Appendix] before taking part.
After the completion of the study, the study proforma sheets would be burnt to dispose of the imprints considering the safety and legal facets.

Results:
The study was conducted in the city -Mangalore, Dakshina Kannada District, located in the coastal region of South India. The participants were mostly the residents from the state of Karnataka and Kerala who came to the hospital for treatment.
A total of 180 respondents were involved in the study, 90 respondents were under cases and 90 respondents were under control. On the whole, the female respondents were more than the male respondents. [ Table 1] While comparing the frequency of the type of impaction with the jaws, it was seen that mesioangular impaction was more commonly seen in mandibular teeth (38:42%; 48:44.1%) whereas distoangular impaction was more common in maxillary teeth (18:31.7%; 28:46.4%). Absent tooth bud was seen to be in more frequency in the maxilla (18: 16.7%; 28: 16.1%) as compared to the mandible (38: 13%; 48: 10.3%). [ Fig. 1] Of the 90 individuals with impacted teeth, 42 individuals (46.7%) had all four teeth impacted followed by two impacted teeth in 21 individuals (23.3%)[ Table 2].
The most common pattern amongst the study participants was LOOP-ULNAR which had been observed more than 50% in 8 ngers (thumb, index, middle and little ngers of the right and the left hand); followed by Whorl-Plain which has been observed more than 50% in 2 ngers (ring nger of both right and left hand). The other patterns were observed in less than 10% of the respondents[ Table 3].
All the study variables were checked for the signi cance of the association with the impaction, and from the above table, it is observed that gender, right hand middle nger, right hand ring nger, and left hand little nger showed signi cant results with the impaction. With respect to gender, the female and impacted third molars with 76.7% were associated, where the p-value was 0.016. In the right hand middle nger, LOOP-ULNAR and impacted third molar with 74.4% were associated where the p-value was 0.024. In the right hand ring nger, WHORL-PLAIN and impacted third molar with 60% were associated where the p-value was 0.028. Similarly, with respect to the left hand little nger, LOOP-ULNAR is associated with both non-impacted and impacted third molar with 61.1%, however, the WHORL-PLAIN ngerprint was observed in the impacted third molar tooth group with 33.3%, the p-value observed was 0.009. However, all the other study variables were not associated with impaction.[ Table 1] Forward stepwise binary logistic regression analysis was performed to predict impaction. Impaction was taken as a dependant variable, along with that, all the versions of the ngerprints of all the ngers were taken as independent variables. All the ngerprints were taken as categorical variables which were divided into 5 categories: loop radial, loop-ulnar, Whorl-Plain, whorl-pocket, whorl-double loop, and arch-plain. The rst variable-LOOP RADIAL was taken as the indicator variable and all the others were compared with the indicator.
Logit equation showed that the dermatoglyphic pattern of the left hand little nger pattern is the single most relevant predictor of impaction with the Whorl-Plain and whorl-pocket pattern having higher odds of impaction. The whorl-pocket pattern had a high odds ratio but statistically was not signi cant but WHORL-PLAIN having an odds of 6.250 was more signi cant for predicting impaction compared to the loop radial group [ Table 4].

Discussion:
Several decades ago, palmistry was widely used by fortune tellers in India to predict the future. It soon dawned, that the hand may be used for the diagnosis of medical and genetic conditions. [18] Hence, dermatoglyphics -the study of ngerprints originated with the term being coined by Harold Cummins in 1926. [19] Fingerprints are ectodermal in origin and are formed during the second trimester of fetal life and remain constant subsequently. Their development is in uenced by genes and environmental factors. Therefore, any abnormality in the uterine environment gets re ected on the ngerprint. Hence, ngerprints can be considered as fossilized evidence of prenatal development. [20] Various methods to record ngerprints have been discussed in the literature. Few such methods are: 1. Ink method-most common method which uses ink and paper 2. Inkless method-use of biometric scan machine 3. Adhesive tape method-uses lead/graphite powder and a transparent tape 4. Photographic method -use of a digital camera [7,12,21] Ink method was prioritized over the other available methods due to its advantages of being an easy, cost effective, user friendly, reproducible, harmless and non-invasive method; while the other stated methods have their own advantages but the paraphernalia required is intensive and expensive.
Fingerprints are individualistic and are different for every individual including monozygotic twins. Dermatoglyphics can be a reasonably reliable tool for investigations with a suspected genetic basis. Their advantages such as ease of use, mass screening, and quick interpretation make it a prized diagnostic aid. From infants to adults, they can be recorded with ease. [12] Several studies have demonstrated a positive association between dermatoglyphics and various chromosomal anomalies. Few such examples are chromosomal disorders like Patau's syndrome, Edwards' syndrome, Down's syndrome, and Cri du Chat syndrome which display atypical dermatoglyphic patterns. The understanding of the relation of dermatoglyphics in dentistry is still in its infancy with little existing literature. Dental conditions like caries, cleft lip and cleft palate, bruxism, malocclusion, periodontal disease, oral submucous brosis, and squamous cell carcinomas of the head and neck region have validated a positive association with dermatoglyphics. [8,22,23,24,25] Decoding skin carvings with the predisposition of certain nger patterns to the presence of an impacted tooth may serve as a clinical cue. Predicting a distoangular impacted tooth known for its high Pederson di culty index based on the nger patterns and its early removal (Henry's abortion) may minimise complications associated with it during its symptomatic removal at a later stage.
This study aimed at nding a relationship between dermatoglyphics and impacted mandibular molars. It was observed that: WHORL-PLAIN pattern in the right hand ring nger, the LOOP-ULNAR pattern in the right hand middle nger, and the WHORL-PLAIN pattern in the left hand little nger were signi cantly related to the presence of impacted teeth as opposed to the control group. The left hand little nger is the single most relevant predictor with the WHORL-PLAIN pattern, validated by forward stepwise binary logistic regression. Similar results were observed in a study conducted by Ramesh et al which demonstrated an increased frequency of whorl pattern on the ring and the index ngers of the right hand in the individuals with impacted teeth whereas an increased frequency of ulnar loop was observed on the index and the little nger of the left hand in the individuals with no impaction. [18] However, contrasting results were observed in a study by Narang et al albeit with a limited sample size (20 subjects) to nd a relation between dermatoglyphics and tooth impaction. They concluded that the tented arch pattern in the index ngers of both hands was observed more frequently in the group with impacted teeth. [26] The limitations of our study include non-randomization of the sampling which resulted in an uneven gender distribution as a consequence of which females were higher in proportion in the impacted third molar group as compared to the males. The glitches encountered in this study are the compliance and patience of the individual during the procedure. Besides, while recording one has to be vigilant as overzealous use of ink or in contrast, insu cient ink makes it di cult to interpret the type of pattern. The predisposition of nger patterns to every individual is unknown. Carter and Matsunaga have hypothesized that the oddities in dermal ridges can only appear when the amalgamation of hereditary and environmental factors exceeds the threshold level. [27] Further large multi-racial, multi-geographical population studies should be carried out to minimize the variation seen in a heterogeneous population [28] , the exact mechanism of inheritance of the pattern of dermatoglyphics, and its predisposition to the type of impaction. This may help to re ne our understanding of variations and replicate these studies amongst various human races.
Dermatoglyphics studies as an adjunct to genetic studies hold promise for deeper insight into the genesis and agenesis of third molars. We believe our study may give an adequate thrust to the scienti c community and a more informed view of corroborating dental variations with the dermatoglyphic patterns.

Conclusion:
Clinical examination and a vivid radiograph are adequate for the diagnosis of an impacted tooth. The application of dermatoglyphics is not to clinch a diagnosis, but as a prophylactic technique employed for the prediction of disease.
An assessment of the Dermatoglyphic pattern is easy, economic, and yields quick results. Dermatoglyphics could serve as a non-invasive screening tool for predicting the presence of impaction, have applications in forensics, aid in early diagnosis that could facilitate streamlining surgical procedures with minimal complications in contrast to symptomatic removal of an impacted tooth.      Figure 1 Multiple Bar Diagram On The Type Of Impaction

Supplementary Files
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