Relationship between Dental Archform and Dermtoglyphics.

AIM: To study the associations of dermatoglyphic pattern and the dental archform among the young adult population.
MATERIALS AND METHODS: The sample consisted of 150 randomly selected patients, within the age ranging from 15 to 25 years. The fingerprint patterns of the study subjects were recorded with a rolling impression technique using blue printer ink and the archform was assessed from the cast prepared from the impression of their lower dental arches. The data obtained were subjected to statistical analysis using SPSS software. The fingerprint patterns for each digit were analyzed and correlated with archform using appropriate statistical tests (chi-square test).
RESULTS: Although no fingerprint pattern was found to be specific for a particular dental archform, increased frequencies of whorls in subjects with square or ovoid archform, high frequencies of ulnar loop pattern with ovoid or tapered archform, and radial loop finger ridge pattern in those with tapered archform were observed.
CONCLUSION: Dermatoglyphic analysis can be used as an indicator for determining the dental archform at an early stage, thereby aiding in the orthodontic treatment of malocclusion aiming to establish favorable occlusion and long-term stability.

INTRODUCTION

In orthodontics, the archform is considered to be important mainly for stability, occlusion, and esthetics.[1] Archform tends to return toward the pretreatment shape after retention. The patient’s pretreatment archform appeared to be the best guide to future archform stability.[2] Archform is the unique expression of individual development and probably no universal design will ever be able to account for the small, but significant, variations in the arch shape of individuals.[3] Recently, there is a widespread use of preformed archwires with varied archforms in orthodontic practice. So it is imperative to select the most suitable archforms according to the patient’s pretreatment archforms, ethnicity, and type of malocclusion.

The epidermal ridges on the finger tips, palms, soles, and toes form distinct and intricate patterns that are unique to each individual. The study of these patterns is termed as “Dermatoglyphics.”[4] The ridge patterns first appear as bulges at about sixth week of intrauterine life and once established, do not change during the rest of prenatal and postnatal life. Since the development of the human dentition, alveolus and palate are also known to occur during the first few months of intrauterine life; it is believed that similar hereditary and environmental factors may govern the establishment of dermal patterns as well as dental tissues.[5] Studies have been performed to determine the association between dermatoglyphics and malocclusion, craniofacial skeletal pattern, and cleft lip and palate.[6] It is speculated that individuals with distinctive dental archforms may also possess peculiar dermatoglyphic patterns. This study was undertaken to evaluate any significant association between the dental archform and finger ridge pattern in young adult population. This study will play an important role in selection of the archwires during the course of orthodontic treatment for establishing a stable occlusion.

MATERIALS AND METHODS

The sample consisted of 150 randomly selected patients from the outpatient department, within the age ranging from 15 to 25 years. Ethical clearance was obtained from the Institutional Ethical Review Committee (No: 137/IHEC/06-18). Informed consent was obtained from all the patients participating in the study. The selected sample possess the following inclusion criteria: (1) full complement of permanent teeth (with exception of third molars), (2) normal tooth size and shape, (3) 5 mm or less arch length discrepancy, (4) Angle Class I malocclusion, and (5) no missing, deciduous, ectopically erupted teeth. Exclusion criteria included the following: (1) prior orthodontic treatment of any type, (2) asymmetric mandibular arches, and (3) Angle Class II/III malocclusion.

Assessment of archform

The impressions of the lower dental arches were taken in alginate impression material and casts were prepared in dental stone. Routine trimming, shaping, and finishing of the cast was done. The archforms were recorded by the procedure followed by Gupta et al.[7] A plain sheet of paper (6 cm × 10 cm) is kept over the occlusal surface of lower cast and stabilized from posterior region with fingers. Index finger of the other hand is moved over the sheet of paper to facilitate transfer of the pencil marks on the sheet. Pencil marks get transferred on the under surface of the sheet of paper and archform is obtained [Figure 1]. The archform thus obtained is compared with the archform template for determining one of the three types (square, tapered, or ovoid).

Figure 1

Recording of the archform of the study subject

Assessment of finger ridge pattern

Recording of fingerprint patterns of the study subjects was achieved with a rolling impression technique using blue printer ink, described by Cummins and Midlo.[8] The fingers were numbered from 1 to 5 for left little finger to the thumb, and from 6 to 10 for right thumb to right little finger of the hand. Duplicating ink was applied with the use of cotton applicator to all the distal phalanges of the fingers and the fingerprint impressions were taken on a white proforma sheet with blocks for each finger [Figure 2]. The fingerprints thus obtained were assessed for plain arch, whorl, or loop (radial/ulnar).

Figure 2

Fingerprints of the study subject, numbered from 1 to 5 for left little finger to the thumb

Statistical analysis

The data obtained were subjected to statistical analysis using SPSS (Statistical Package for Social Sciences, version 16.0) software. The fingerprint patterns for each digit were analyzed and correlated with dental archform groups using appropriate statistical tests (Pearson’s chi-square tests). The level of significance was P < 0.05.

RESULT

The study sample was composed of 150 subjects with square archform (42 subjects), ovoid archform (47 subjects), and tapered archform (61 subjects). Table 1 shows the distribution of fingertip patterns according to digit and archform types. Analysis of the fingerprints obtained revealed that the subjects with whorl pattern had square or ovoid archform, the subjects with ulnar loop had tapered archform, and the subjects with ulnar loop had ovoid or tapered archform. The plain arch finger ridge patterns on the whole were less frequent among the study subjects.

Table 1

Distribution of dermatoglyphic patterns on each fingertip in each type of dental archform

Type of pattern	Hand	Plain arch			Radial loop			Ulnar loop			Whorl
Archform		Square	Tapered	Ovoid	Square	Tapered	Ovoid	Square	Tapered	Ovoid	Square	Tapered	Ovoid
Digit 1	Right**	5	10	7	5	14	5	5	19	21	27	9	23
	Left*	8	5	6	3	12	3	11	26	23	0	9	24
Digit 2	Right	3	5	6	5	13	5	6	18	24	28	16	21
	Left	6	6	8	1	16	2	13	22	23	22	8	23
Digit 3	Right**	3	4	4	8	16	11	7	18	23	24	14	18
	Left**	3	3	5	2	15	4	16	27	29	21	7	18
Digit 4	right	3	1	3	4	12	12	9	17	23	26	22	18
	Left*	3	2	3	2	17	2	10	20	20	27	14	30
Digit 5	Right*	4	3	8	7	14	16	11	18	15	20	17	17
	Left**	4	3	5	4	19	7	9	28	29	25	2	15

*P < 0.05; **P < 0.01.

Dermatoglyphic pattern frequencies differed significantly according to archform types (P < 0.01; Table 2). In the square archform group, ulnar loops were present in 23% of subjects, radial loop in 10%, whorls in 57%, and arches in 10%. In tapered archform group, 40% of the subjects demonstrated whorls, 35% had ulnar loops, 24% had radial loop, while the remainder presented with arches. Ovoid archform subjects presented with predominance of ulnar loops (49%) followed by whorls (25%), radial loop (14%), and arches (12%) [Figure 3].

Table 2

Distribution of dermatoglyphic patterns in each type of dental archform

	No. of subjects (n)	No: of finger prints studied (n × 10)	No. of whorl patterns	No. of plain arches	No. of ulnar loops	No. of radial loops
Square archform	42	420	240 (57.1%)	42 (10%)	97 (23.09%)	41 (9.7%)
Ovoid archform	47	470	118 (25.1%)	55 (11.7%)	230 (48.9%)	67 (14.2%)
Tapered archform	61	610	207 (33.9%)	42 (6.88%)	213 (34.9%)	148 (24.2%)

P < 0.01 (chi-square analysis).

Figure 3

Distribution of fingertip patterns in the three archform groups

DISCUSSION

One of the most significant steps in the success of orthodontic treatment of the patient is the selection of archwire with appropriate archform. The size and shape of the dental arches have considerable implications for orthodontic diagnosis and treatment planning.[9] There are various methods proposed for selecting the archwire with the suitable archform, but these remain to be topics of controversy. Archforms were first classified as square, ovoid, and tapered by Chuck in 1932. Such a three-archform approach allows for greater individualization than the single archform approach, especially in the early archwire stages.[10]

Othman et al. compared the archforms (square, tapered, and ovoid) according to different classes, the most common archform in class I was the ovoid followed by tapered; however, in class II and class III subjects, the most common arch forms were tapered.[11] Several studies used archform templates for the evaluation of photocopies of dental models. Paranhos et al. noted the prevalence of dental arch shape to be oval (41%), followed by square (39%), and tapered (20%) shapes.[12] As far as esthetics is concerned, tapered archform presents a better smile arc than square archform.[13]

In the present study, dermatoglyphic patterns were assessed to determine the association, if any, between archform and finger ridge pattern. The aim of specification of the archform was to evaluate the final archform that will be obtained by the use of fixed orthodontic appliances in patients who have referred to orthodontic clinic due to orthodontic malocclusion.

There are several studies to estimate the association between the dermatoglyphics and different classes of malocclusion. Reddy et al.[14] conducted a study to compare the dermatoglyphic parameters of individuals with normal occlusions and various classes of malocclusions and concluded that significantly higher proportion of whorl pattern in class I compared to the class II and III. Significantly higher proportion of subjects from class II and III had loop pattern compared to the class I. Increased proportion of loops was found in class III compared to class II, but was not statistically significant.

In the present study, analysis of fingerprints so obtained revealed that the subjects with whorl pattern have square or ovoid archform, the subjects with ulnar loop have tapered archform, and the subjects with ulnar loop have ovoid or tapered arch form. The plain arch finger ridge pattern on the whole were less frequent among the study subjects. The information thus obtained from the present study can be used in the selection of the archwires used during the course of orthodontic treatment. Hence, square or ovoid archwire can be used for subjects with whorl finger ridge pattern, ovoid or tapered archwire can be used for subjects with ulnar loop pattern, and tapered archwire can be used in subjects with radial loop ridge pattern.

The previous study conducted to identify the association, if any, between type of dental archforms and type of dermatoglyphic patterns in 90 dentulous subjects for dermatoglyphic assessment of long-standing edentulous subjects may help to identify the patient’s preexisting dental archform and thus aid in proper tooth arrangement.[15] The result of this study confirms the findings of the present study.

The knowledge from the present study may help to identify the original dental archform the patient possess and thus aid in favorable archwire selection. Though a number of conclusive findings were observed, this is, by no means, the end to the establishment of dermal and dental arch relationships. This study is only a preliminary observational study in which individuals from just one particular geographic area and similar ethnicity have been examined. The results obtained can be further corroborated through more conclusive studies on individuals of varying ethnic and geographical backgrounds. Similar results in studies on a larger, more stratified sample may further establish the role of dermatoglyphics as an important guide to dental archform selection to improve the treatment outcome and stability.

CONCLUSION

Subjects with whorl pattern have square or ovoid archform, the subjects with ulnar loop have tapered archform, and the subjects with ulnar loop have ovoid or tapered archform. Dermatoglyphic analysis can be used as an indicator for determining the dental archform at an early stage, thereby aiding in the orthodontic treatment of malocclusion aiming to establish favorable occlusion and long-term stability. Specific dermal patterns relating to an individual’s identity may also help instill new interest in the field of forensic odontology.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.