Gender and age effects on dental and palatal arch dimensions among full siblings

Abstract

Purpose: This study was conducted to investigate the dental and palatal arch dimensions of male and female siblings in relation to gender and age, using three-dimensional (3D) digital casts.

Methods: This study involved 54 subjects (27 pairs) of male-female siblings aged 15 to 45 years. Dental casts were digitized and analyzed for tooth size (TS), arch width (AW), arch length (AL), arch length discrepancy (ALD), and palatal arch dimensions (PAD). The data obtained were subjected to t-tests, and the palatal curvature (PC) was modeled using a fourth-order polynomial.

Results: Significant differences (P < 0.05) between the sexes were found in the mesiodistal TS, particularly in all canines, as well as 16, 36, 46, and 41. Maxillary AW and AL were also significantly (P < 0.05) influenced by sexes. Most arch parameters were more prominent in male siblings, and the effect of age on PC differed between the sexes. In addition, the PC of adolescent females was mostly superimposed on adult females relative to males.

Conclusion: Among siblings, males were found to have significantly larger dental arch dimensions than females. Furthermore, PC showed some differences between the sexes in both the frontal and sagittal planes.

Introduction

Dental arch dimensions, including the width and length of the arch and palatal curvature (PC), are important values for diagnosis, treatment planning, and treatment outcome in patients of all age groups seeking orthodontic treatment. It is well known that dental arch dimensions continue to change throughout growth and development. However, information on members of the same family can be valuable to orthodontists for predicting the effects of facial growth on occlusion. It is well established that familial resemblances are intrinsically linked to the development of craniofacial structures [1,2].

Studies of siblings are of interest because of the shared nature of genetic inheritance in families, as siblings share 50% of their genes by descent, while the remaining variation is presumably attributable to environmental factors. Hence, because of such resemblances, there is a clinical perception that siblings will exhibit similar occlusal characteristics. Likewise, brothers and sisters within a typical family will share many common environmental factors, including maternal effects, dietary and nutritional patterns, socioeconomic status, and even illness patterns. This combined impact of nature and nurture places siblings on a comparable growth and developmental pathway [3].

The study of facial growth and occlusion becomes more interesting when gender and age-related effects are included. The actual direction and magnitude of growth in the dental arch are still being debated, and longitudinal studies have indicated that arch width (AW) increases and arch length (AL) decreases with age. This change leads to a shorter and broader dental arch over time, and the most significant changes are evident in the second and third decades of life, followed by a plateau [4]. Palatal growth in males continues even after the completion of full permanent dentition, whereas in females, signs of aging become apparent in late adolescence [5]. However, no similar data on dimensional changes in dental arch parameters have yet been available for siblings of the opposite sex.

Orthodontic treatment aims to stabilize the phenotype of an individual. The more significant the genetic component of any anomaly, the more challenging it becomes to achieve this aim. On the other hand, if the anomaly is due more to environmental factors, it becomes easier to intercept and prevent its further development [6]. The severity of any phenotype depends on not only genetic, epigenetic, and environmental factors but also their interaction over time. In any individual, the success of orthodontic treatment depends on the complex interaction of genetic and environmental factors at a specific stage of development [7]. Through familial research, it is possible to differentiate the effects of genetic and environmental factors in relation to gender and age.

Typically, previous studies of siblings have neglected to describe dental arch and palatal dimensions in terms of the complexity of size and shape in relation to gender and age. Identification of specific morphological differences and similarities among family members can provide valuable insights for enhancing the evaluation and predicted outcome of orthodontic/dentofacial orthopedic procedures, such as maxillary expansion and tooth extraction. Such additional information can improve the effectiveness of these treatments.

Direct analysis of the palate is commonly performed using stone casts and measurements obtained using calipers. More recent indirect techniques have involved 2D projections (radiographs, photographs, or photocopies). However, some landmarks on the palate have been identified as insufficient, prone to error, or hindering palatal morphology [8]. Advances in technology and software – not specifically for dentistry – such as the engineering software SprutCAM (Sprut Tech Ltd., Limassol, Cyprus) and Microsoft 365 Excel 2016 (Microsoft Corp., Redmond, WA, USA) now allow detailed measurement of the curvature and depth of the palate. This approach involves the use of 3D coordinates of identified landmarks, and has proven to be reliable. The curvature of the palatal surface can then be obtained using a fourth-order polynomial equation [5,9].

The aim of the present study was to investigate the differences in dental arch dimensions between male and female siblings and to clarify the effects of age (adolescents and adults) and gender on the form (size and shape) of the hard tissue palate among siblings.

Materials and Methods

Ethical approval and sample size calculation

Ethical approval was obtained from the National University of Malaysia (UKM) Research Ethics Committee (JEP-2017-574). A sample size calculation was performed, with 80% estimated power at a 5% margin error and 95% confidence interval (CI). The mean difference (MD) was 1.6, and the standard deviation (SD) was 2.79 [10]. Hence, the target sample size was 27 pairs of male-female siblings (including an additional 20% to account for some potentially damaged casts).

Study design and participants

All participants were recruited from the Klinik Rawatan Utama (Primary Dental Clinic) of UKM through systematic convenience sampling. Prior to the study, the nature and purpose of the study were explained to each participant, and their consent was obtained. For subjects below age 18, permission was obtained from their guardians. The inclusion criteria were 1) age between 15 and 30 years; 2) first-degree siblings, as avowed by the parents (no serological or other test was used to confirm kinship); 3) all permanent dentition intact, excluding third molars or showing only minor restorations and no obvious attrition; 4) no history of orthodontic treatment; 5) no history of poor periodontal health or previous extraction; and 6) no chronic medical conditions or craniofacial anomalies.

After clinical examination, impressions of the maxillary and mandibular arches were made using fast-setting alginate (Lascod SpA, Florence, Italy). Dental stone (Dentona AG, Dortmund, German) was then immediately poured into the impression to obtain a dental cast. All dental casts were checked for any significant fractures or damage to the teeth that could affect the dimensions of the crown.

All the dental casts were scanned using a non-contact-type structured 3D light scanner, Rexcan CS+ (Solutionix, Seoul, RO Korea) and its supporting software, ezScan 2017 (Solutionix). Before every scanning process, the scanner was calibrated in accordance with the manufacturer’s guidelines. The dental casts were scanned at 39 predetermined angles (point clouds) for 10-15 min. Afterwards, the scanned images were aligned and merged to produce a 3D digital image of each dental cast. The digital images were then saved and exported into stereolithography (STL) file format. Finally, the digital casts were evaluated using Geomagic Studio software, version 2013 (3D Systems Inc., Rock Hill, SC, USA) and SprutCAM software (Sprut Tech Ltd.)

Measurements

Five parameters (Table 1) were measured as dental arch dimensions: mesiodistal TS (Fig. 1A), AL (Fig. 1B) [11], AW (Fig. 1C) [12,13], arch length discrepancy (ALD), and palatal arch dimensions (PAD; Fig. 1D) [14]. Under certain circumstances, with spacing or a median diastema, the AL was measured by omitting the spacing. In addition, no AW measurements were made if the teeth were rotated or excluded from the arch. All linear measurements were measured with Geomagic Studio software, version 2013 (3D Systems Inc.).

As for the PAD (Fig. 1D), the incisive papilla (IP), the posterior-most limit of the palatal raphe (PR), the palatal sulci of the first molars (16, 26), the gingival margins of the premolars (15, 25, 14, 24), and the gingival margins of the canines (13, 23) were identified and marked accordingly. The intermolar (16-26) line and its perpendicular line starting from IP were traced. The intersection point between these two lines was then marked as M.

The initial step involved establishing a protocol for the frontal and sagittal planes. In the frontal plane, the origin of the axes was set at 16 (x-axis corresponding to the 16-26 line; y-axis to its vertical perpendicular). Afterwards, the same protocol was implemented on the other frontal planes according to the corresponding tooth. In the sagittal plane, the origin of the axes was positioned at IP (x-axis corresponding to the horizontal projection of IP–M; y-axis to its vertical perpendicular). The same protocol was also applied to the IP-RP plane. Next, SprutCAM software (Sprut Tech Ltd.) was used to digitize approximately 12 to 20 equidistant landmark coordinates (x, y, z) on the curvatures of the palate for the frontal and sagittal (IP-M) plane [14]. The coordinates for RP were digitized on the IP-RP plane.

The 3D coordinates gathered were translated and modeled with a fourth-order polynomial (y = ax + bx² + cx³ + dx⁴) for the four frontal planes and one sagittal (IP-M) plane in Microsoft 365 Excel 2016 (Microsoft Corp.). The linear and angle parameters (Table 1) were measured using the trigonometry formula in the spreadsheet.

Table 1 Measurement parameters

Parameter	Measurement
Tooth width (Fig. 1A)	Mesiodistal tooth width anterior to first molars
Arch length (Fig. 1B)	Measured by the segmental arch approach anterior to the first molar [11]
Arch width (Fig. 1C)	Maximum distance between cuspal tips of upper and lower canines, first and second premolars, and first molars [12,13]
Tooth-size arch length discrepancy	Difference between arch length and the total mesiodistal width of the tooth anterior to first molars
Palatal arch dimension [14] (Fig. 1D)	Sagittal plane: palatal length (mm) - horizontal projection of IP–M line; palatal slope (°) - the slope of the maximum palatal height versus the horizontal axis; maximum palatal height (mm) Horizontal plane: angles between the IP-RP and the IP-M lines (°) Frontal plane: palatal width and mid-palatal height (distance; mm) at the first permanent molar (16-26), second premolars (15-25), first premolars (14-24), and canines (13-23)

IP, incisive papilla; PR, posterior-most limit of palatal raphe; M, intersection point between the intermolar and its perpendicular line starting from IP.

Fig. 1

Measurement parameter: (A) Tooth size; (B) Arch length; (C) Arch width; (D) Palatal arch dimensions. IC, intercanine; IPM1, interpremolar 1; IPM2, interpremolar 2; IM, intermolar; IP, incisive papilla; RP, the posterior-most limit of the palatal raphe; M, the intermolar 16-26 line intersects the perpendicular line

Error of method

The reliability of the measurements (intra- and inter-examiner reliability) was assessed on five random digital casts and by repeated landmark identification with digitization of the same casts. The casts were remeasured after a two-week interval. Subsequently, the data were analyzed using the intraclass correlation coefficient (ICC). Test-retest reliability was also evaluated by rescanning the same five dental casts. Statistical analysis of the measurements obtained from the first and second scans was done using ICC. The ICC scores varied from 0.922 to 1.000 for intra-examiner reliability, 0.890 to 1.000 for inter-examiner reliability, and 0.923 to 1.000 for test-retest reliability. Thus, the results of the reliability test demonstrated excellent agreement.

Statistical analysis

The data were analyzed using the Statistical Package for the Social Sciences (SPSS) Version 23 (International Business Machine Corp., New York, NY, USA). The means and SD were calculated for all parameters separately for each gender. The data distribution was analyzed using the Shapiro–Wilk normality test, and all data were normally distributed (P > 0.05). An independent t-test was used to compare the MD in the dental arch dimensions between the male-female sibling groups. The palatal arch form and shape were categorized into their respective age groups and illustrated in graph form.

Results

Demographic data

A total of 54 siblings (27 males and 27 females) with a mean age of 17.67 ± 4.29 years participated in this study. The participants were from different ethnicities: 28 (51.8%) Malay, 20 (37%) Chinese, and six (11.2%) Indian. There was no significant age difference (P > 0.05) between the sibling groups.

Dental arch dimensions

As shown in Table 2, there were statistically significant (P < 0.05) differences among male siblings with a larger mesiodistal TS of 41, all canines (13, 23, 33, and 43), and 26, 36, and 46.

As shown in Table 3, there were significant differences (P < 0.05) in all the variables of the AW (IC, IPM1, IPM2, IM) and AL between the groups. In addition, males exhibited a significantly (P < 0.05) larger maxillary AW and AL in comparison to females. However, both males and females showed similar levels of crowding in the ALD (MD maxillary arch = 1.796 mm; mandibular arch = 0.177 mm).

Analysis of the PAD (Table 4) showed that it was approximately 3-5% larger in males than in females across all three planes (sagittal, horizontal, and frontal). However, measurement of height involving the first molar demonstrated a significant difference (P < 0.05). Additionally, females exhibited a slightly higher MD of the palatal raphe inclination (0.502 mm) than males. However, this difference was not considered clinically significant (P > 0.05).

Table 2 Comparison of tooth size among siblings by means of independent t-test

Variables	Male (mm)		Female (mm)		Independent t-test
	mean	SD	mean	SD	MD	SED	95% CI
							lower	upper
Maxillary teeth
16	10.656	0.523	10.382	0.640	0.274	0.159	-0.046	0.593
15	6.888	0.458	6.795	0.468	0.093	0.126	-0.160	0.346
14	7.223	0.482	7.085	0.542	0.137	0.140	-0.143	0.418
13	8.182	0.545	7.819	0.538	0.363*	0.147	0.067	0.659
12	7.330	0.556	7.057	0.577	0.273	0.154	-0.036	0.582
11	8.797	0.503	8.608	0.598	0.188	0.150	-0.113	0.490
21	8.653	0.564	8.473	0.548	0.180	0.151	-0.124	0.483
22	7.209	0.626	6.985	0.631	0.224	0.171	-0.120	0.567
23	8.169	0.525	7.832	0.455	0.336*	0.134	0.068	0.605
24	7.222	0.452	7.056	0.543	0.166	0.136	-0.107	0.438
25	6.772	0.443	6.744	0.465	0.028	0.124	-0.220	0.276
26	10.635	0.615	10.198	0.669	0.438*	0.175	0.087	0.789
Mandibular teeth
36	11.185	0.543	10.789	0.680	0.396*	0.168	0.060	0.733
35	7.379	0.519	7.290	0.766	0.089	0.178	-0.268	0.447
34	7.329	0.500	7.055	0.565	0.274	0.145	-0.017	0.565
33	7.188	0.499	6.685	0.400	0.503**	0.123	0.256	0.750
32	6.106	0.406	5.977	0.384	0.128	0.108	-0.088	0.344
31	5.569	0.288	5.429	0.352	0.141	0.088	-0.035	0.316
41	5.580	0.288	5.407	0.326	0.173*	0.084	0.005	0.341
42	6.088	0.372	5.991	0.366	0.097	0.100	-0.105	0.298
43	7.142	0.535	6.704	0.394	0.438*	0.128	0.182	0.695
44	7.256	0.531	7.054	0.582	0.201	0.152	-0.103	0.506
45	7.318	0.506	7.062	0.495	0.255	0.136	-0.018	0.528
46	11.125	0.551	10.715	0.585	0.410*	0.155	0.100	0.721

SD, standard deviation; MD, mean difference; SED, standard error difference; CI, confidence interval; IC, intercanine; IPM1, interpremolar 1; IPM2, interpremolar 2; IM, intermolar; IP-M, incisive papilla-molar distance; statistical significance; *P < 0.05, **P < 0.001

Table 3 Comparison of dental arch dimensions among siblings by means of independent t-test

Variables	Male		Female		Independent t-test
	mean	SD	mean	SD	MD	SED	95% CI
							lower	upper
Maxillary arch width (AW)
IC	36.000	2.160	34.288	2.760	1.712*	0.675	0.359	3.066
IPM1	42.866	2.568	40.272	2.618	2.594*	0.706	1.178	4.010
IPM2	47.112	3.417	45.046	3.097	2.066*	0.887	0.285	3.847
IM	52.595	2.879	49.710	2.942	2.885*	0.792	1.296	4.475
Arch length (AL)
Maxillary	74.778	4.991	71.516	4.664	3.263*	1.315	0.625	5.900
Mandibular	64.055	3.686	61.327	5.010	2.728*	1.197	0.326	5.130
Arch length discrepancy (ALD)
Maxillary	-1.144	4.878	-2.941	4.838	1.797	1.322	-0.856	4.450
Mandibular	-3.167	5.075	-3.345	4.963	0.178	1.366	-2.563	2.920

SD, standard deviation; MD, mean difference; SED, standard error difference; CI, confidence interval; IC, intercanine; IPM1, interpremolar 1; IPM2, interpremolar 2; IM, intermolar; statistical significant; *P < 0.05, **P < 0.001

Table 4 Comparison of palatal arch dimension among siblings by means of independent t-test

Variables		Male		Female		Independent t-test
		mean	SD	mean	SD	MD	SED	95% CI
								lower	upper
Sagittal	IP-M (mm)	32.580	2.314	30.716	2.452	1.863*	0.649	0.561	3.165
	slope (º)	24.110	3.946	22.820	5.018	1.291	1.228	-1.174	3.756
	height (mm)	13.291	2.314	11.878	2.604	1.413*	0.670	0.068	2.759
Horizontal	raphe (º)	2.387	1.884	2.965	3.306	-0.578	0.732	-2.047	0.892
Frontal
IC	width (mm)	31.294	2.639	0.283	2.077	1.011	0.646	-0.286	2.308
	height (mm)	3.059	1.503	3.010	2.021	0.050	0.485	-0.923	1.022
IPM1	width (mm)	32.443	2.829	30.442	2.460	2.001*	0.721	0.553	3.448
	height (mm)	7.833	1.889	8.336	1.505	-0.502	0.465	-1.435	0.431
IPM2	width (mm)	35.400	3.089	33.156	2.553	2.244*	0.771	0.697	3.792
	height (mm)	12.590	1.955	12.129	1.842	0.462	0.517	-0.575	1.499
IM	width (mm)	37.415	3.076	34.772	2.342	2.643*	0.744	1.149	4.136
	height (mm)	13.972	1.872	12.572	2.458	1.400*	0.595	0.207	2.593

SD, standard deviation; MD, mean difference; SED, standard error difference; CI, confidence interval; IC, intercanine; IPM1, interpremolar 1; IPM2, interpremolar 2; IM, intermolar; statistical significant; *P < 0.05, **P < 0.001.

Palatal curvature

The effect of age on PC differed between the sexes, as assessed by the fourth-order polynomial, y = ax + bx² + cx³ + dx⁴ (Fig. 2). Comparison of the curves for IM in the frontal plane showed that among males, the adolescent group displayed a lower curve than the adult group (Fig. 2-1A). The curves for IPM2 and IPM1 in males (Fig. 2-2A, 3A) and for IPM2 in females (Fig. 2-3B) showed a similar pattern. Conversely, the curves for IM in females were mostly superimposed between the adolescent and adult groups (Fig. 2-1B).

On the other hand, the curves for IC in the frontal plane showed a reverse pattern in both sexes, the curves for the adolescent group being more dominant and having a steeper curve than those for the adult group (Fig. 2-4A, 4B). In addition, there was a noticeable decrease in the height and width of the curves in the adult group among male-female siblings (Fig. 2-4A, 4B).

The curve for males showed a consistent increase in size and shape in the adult group relative to the adolescent group in the sagittal plane (Fig. 3A). This pattern was also observed in females (Fig. 3B). The curve in adults closely matched that of adolescents, with only a minor difference in increment. However, as the curve approached the terminal end of the adult group, it showed a decrease.

Generally, the palatal form (size and shape) in adolescent females was similar to that in adults. In males, there was a significant and asymmetrical increase in both palatal height and width when adolescents were compared to adults. However, there was still potential for modifications in the PC for adolescents and young adults, in terms of both linear and angular dimensions.

Fig. 2

Frontal plane of the palatal curvature in males (A) and females (B). X- and Y-Axis Unit in mm (not to scale). 1; intermolar; 2, interpremolar 2; 3, interpremolar 1; 4, intercanine; Green line, adolescents; Red line, adults

Fig. 3

Sagittal plane projections in males (A) and females (B). X- and Y-Axis Units in mm (not to scale). IP, incisive papilla; Green line, adolescents; Red line, adults

Discussion

This study focused on the influence of sexual dimorphism in opposite-sex siblings. Sexual dimorphism refers to the variations in physical characteristics between male and female individuals of the same species, primarily observable in their external appearance. At the phenotypic and molecular levels, such sexual dimorphism has important implications for disease onset, progression, and treatment. Recent research has provided novel insights into sex/gender medicine, focusing on sex/gender-related differences in disease [15].

Extensive research has adequately documented the significant variations in human dentition and arch size between males and females. For example, males have a larger TS than females [16,17]. Furthermore, the mesiodistal TS exhibits particular characteristics in the context of gender and race [18]. Hence, this area of study is of anthropological significance and can provide information on human evolution in relation to technological and dietary changes [19].

In this study, male siblings had a larger mesiodistal TS than females in all canines and first molars, except for 16. Studies have consistently found increased TS for males relative to females among African-American, Caucasian, and Japanese populations [18,19,20]. Furthermore, the main differences in mesiodistal tooth crown diameters observed between males and females have primarily been for the canine and molar teeth.

Although the biological basis for sex differences in the canines remains unknown, previous studies have suggested that the dimensions of canines may be influenced relatively independently by the sex chromosomes [21]. The development timing of canines may have an impact on sexual dimorphism through the genes involved. [22]. Although there are variations between males and females, the differences are inconsistent for all teeth [23,24]. Similar trends have been observed in other populations, including Filipinos, Nepalese, Southern Chinese, and Australian aborigines [25,26,27,28].

There are three prominent ethnic groups in Peninsular Malaysia: Malays, Chinese, and Indians. Malays and Chinese belong to the Mongoloid race, while Indians constitute the Indo-Dravidian (Indo-European) Caucasoid subgroup. Generally, Mongoloids have a parabolic arch with large incisors, canines, small premolars, and large molars. Caucasoids, on the other hand, usually have narrow V-shaped arches with smaller anterior teeth and tend to present with more anterior crowding [29]. The mean values for mesiodistal TS in the present study were closely related to the values reported for Southern Chinese [27]. On average, the TS was more prominent than in Caucasians but smaller than in Australian aborigines.

The present study showed that AW and AL were significantly more prominent in males than in females. A previous study found that male arches are wider and grow longer than those in females [4]. However, these sex differences were interpreted in terms of the onset of the adolescent growth spurt [10]. In addition, evolutionary studies of sexual dimorphism in human dentition support the contention that larger jaws in men provide a mating advantage since women consider an apparently dominant and masculine facial profile attractive [30].

The palatal arch is a useful variable for ethnic and sex identification. The palate has been used to classify major racial groups in America, and it has been concluded that AW of the canine and premolar regions is a racial discriminator, while that in the molar region is a sex discriminator [31]. It has also been shown that the canine and premolar regions are broader in Afro-Americans than in Euro-Americans [20]. While subtle changes occur with aging in individuals, inter-individual variations are much too significant for detection of any age effects among cross-sectional data. Racial discriminators are mainly in the mid arch (canine and premolar region), while the molar region provides sex discriminators.

The present study found significant sex differences in ALD for the maxillary arch. In addition, a study that analyzed the heritability of Bolton’s discrepancy in siblings demonstrated significant differences in the mesiodistal TS of males relative to females because of sexual dimorphic differences [32].

Classification of the age ranges for adolescents (mean age = 14.60 ± 1.19) and adults (mean age = 21.12 ± 3.97) may seem arbitrary. This is because the timing of the pubertal growth spurt differs in both sexes, and most of the adolescent females analyzed were probably already beyond their pubertal growth spurt. However, no assessment of pubertal status was made in the present subjects. Therefore, conclusions were made on the basis of dental and chronological ages. These two age groups correspond to the start of complete permanent dentition (adolescents) and the possible steady stage of dentition before any significant effects of aging become apparent (adults).

The polynomial function (fourth order) was a reasonable type of analysis for yielding a naturally smooth curve and differences in the curvature of the dental arch [33,34]. This curve is considerably flexible, can be fitted to any size or shape, and can include asymmetries. Hence, the mathematically produced curve does not become irregular and can represent any size or shape that fits an individual.

A potential effect of age, even after establishment of the permanent dentition, can occur through fusion of the craniofacial sutures [35]. In the present study, there were more age-related changes in males than in females. Increments in palatal dimensions and a ‘higher’ and ‘wider’ PC were found in adult males relative to adolescent males. In contrast, the palatal dimension did not differ much between adolescent and adult females, although some decrements were observed (signs of aging), especially for palatal height in adult females. This showed a general trend for craniofacial growth, with faster and earlier attainment of biological maturity in females than in males [5,36,37].

Overall, the PC of adolescent females suggests attainment of adult characteristics. However, in males, some palatal bone growth and remodeling did occur (with size increment and shape variations) between adolescence and young adulthood. In this study, the palatal gingiva of the canines, first and second premolars, and first molars were used as the reference points (coordinates 0,0,0). However, this may not accurately explain asymmetrical appearance of the PC in the frontal plane, as the reference points can be influenced by the characteristics of the related teeth, such as arch rotation and crowding of the arch. In addition, the PC varies significantly and is related to various factors of interest, including breathing pattern and occlusion [38,39].

Examination of an older sibling can assist clinicians in predicting the dental development and craniofacial growth of the younger sibling. In other words, clinicians can foresee any change leading to malocclusion and intercept and prevent it if necessary. This extra evidence can make clinical judgment more accurate and minimize any subjectivity related to diagnosis and the complexity of the assessment. In this way, clinicians can provide more appropriate treatment options tailored to the needs of individual patients.

The present findings also support the importance of odontometric and palatal metric profiling as adjunctive diagnostic elements in forensic situations. There is evidence that TS, PAD, and PC can be reliable sex and racial discriminators [22,23,34,38]. Furthermore, information about the sex of human individuals is essential for identification, especially in cases where the maxillary arch is the only diagnostic element available, or to assist forensic anthropologists in situations where the ethnicity is uncertain. Hence, the findings of familial research may be of help for creating a predictive model solely for Malaysian data.

A national familial registry is equivalent to a ‘people’s bank’. Such a registry can assist clinicians in recognizing the dental health challenges that individuals face and help to understand the progress of dental diseases for future prevention and treatment. Meanwhile, the government can optimize its budget and expenses more efficiently by focusing on the health needs of communities. This strategy aligns with the vision of improving oral healthcare status in conformity with the country’s socioeconomic development.

The primary limitation of this study was its cross-sectional design, as it did not determine any ‘cause-and-effect’ relationships. It is essential to acknowledge that sampling bias is inevitable, and it is possible that the sample may not have represented the entire population. Furthermore, subject selection was based on convenience sampling, and there were no sex-specified sibling groups (male-male and female-female) that could have served as controls. A larger sample size would have increased the sensitivity of the statistical analysis. However, as this was a pilot study, the goal at this stage was to obtain primary trend or normative sibship data. A large-scale, multi-center longitudinal familial research study would be appropriate in multiracial Malaysia. In addition to sex, race can also play a role in determining dental arch dimensions. More conclusive findings might be obtained by assessing the effect of racial differences in developing human dentition.

The findings of this study regarding the characteristics of teeth and the palate will provide valuable information for treatment planning, and may also encourage more interdisciplinary dentofacial therapy and orthodontic care. Palatal growth in patients should also be investigated to assist with treatment planning. Knowledge of alterations during development of the maxillary arch and palate at different ages is extremely valuable for deciding the correct timing of functional rehabilitation.

Conflict of Interest

The authors have no potential conflicts of interest to declare.

Acknowledgments

This study was supported by Geran Universiti Penyelidikan (GUP-2019-029), The National University of Malaysia.

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