Gender-based evaluation of positional variations of gingival papilla and its proportions: A clinicoradiographic study.

Background: The proportionate presence of natural teeth, gingival tissues along with the interdental papilla (IDP) is critical components of an esthetic smile. Hence, the present study examined the IDP height (PH), its position clinically and radiographically as papilla proportion (PP) and crestal PP (CPP). Materials and
Methods: The study included 120 patients with healthy periodontium with an age group of 20-40 years, equally divided as males and females. The maxillary anterior interdental sites from canine to contralateral canine were examined for PH, PP, crestal PH (CPH), and CPP.
Results: The mean values of PH, PP, CPH, and CPP were found to be greater on the mesial aspects of all the teeth as compared to the distal aspects. The females exhibited overall higher values than males for all the parameters. Majority of the teeth exhibited statistically significant differences for PP on mesial aspect when compared based on gender with mean values of 44.58% ±3.35% (males) and 47.17% ±3.23% (females) (P < 0.0001) for central incisor (CI). The CPP on mesial aspect for CI was 50.57% ±3.51% (males) and 54.21% ±3.76% (females) with P < 0.0001. A similar trend was followed in other teeth.
Conclusion: The maxillary anterior teeth exhibit greater values on mesial aspects for parameters such as PH, PP, and CPP in both the gender thereby indicating an apical positioning of the IDP tip on distal aspect when compared to mesial. Furthermore, the values and differences were more pronounced in females than the males. Copyright:

INTRODUCTION

One of the critical components considered for restoration and rehabilitation of periodontal apparatus and the natural teeth includes the interdental zone, which comprises of teeth contact area, interproximal embrasures, and the interdental papilla (IDP). Among these, the IDP acts as a natural barrier that protects the underlying periodontal structures and is a key element in influencing esthetics in an individual.[12] Although attempts have been made to restore the proximal soft-tissue defects through regeneration, the IDP presents realistic challenges in attaining its original dimensions, especially in terms of its height, width, and color. These characteristics of the soft tissues in the interdental areas are influenced by crown forms, tooth contact areas, and vertical and horizontal distance between the proximal surfaces.[34]

With an enhanced understanding, awareness and expectations of patients demanding an esthetic smile, the clinicians have been dependent on the principles of golden proportions and mathematics for designing smiles for their patients. Proportionate existence of the clinical crown with the IDP has been emphasized as a key consideration in periodontal and restorative procedures. The apico-coronal appearance of papilla along with the midfacial gingiva are critical parameters while smiling and constitute a positive soft-tissue architecture esthetics.[56] It has been estimated that the IDP height (PH) reduced from anterior to posterior teeth in maxillary anterior sextant.[7]

The papilla proportion (PP) and the crestal PP (CPP) have been evaluated independent to each other previously and are proposed to be considered as guidelines for smile designing in the anterior sextant.[89]

The literature search revealed that the above two parameters, i.e., PP and CPP have not been evaluated together to assess if any relationship exists between the two. Furthermore, their combined assessment in either of the gender is thought to provide a meaningful parameter in guiding the clinician toward successful periodontal and restorative procedures. Hence, the present study was undertaken to assess the IDP position clinically and radiographically measured as mathematical percentage ratio with respective crown length (CL) as PP and CPP in periodontally healthy males and females. Along with the above aim, it was also thought necessary to evaluate and correlate the mesial and distal PP (MPP and DPP) and CPP of the maxillary anterior teeth.

MATERIALS AND METHODS

A total of 120 periodontally healthy patients were recruited for the present cross-sectional comparative study equally segregated into males and females with age ranging from 20 to 40 years, visiting the Department of Periodontology and Implant Dentistry of our institute formed the study sample population. After presentation of the study protocol which adhered to provisions of Helsinki Declaration, the approval of Institutional Ethics Committee was procured, and the study was registered with the Clinical Trials Registry of India (CTRI/2020/03/024282). The participants were informed about the nature of the clinical trial and a written informed consent was obtained from them thereby facilitating their recruitment in the study. In the absence of any gender-specific data showing comparison of mesial and distal PH and proportions for any tooth, an effect size of 0.5 (medium as per Cohen) was targeted in the proposed study. To detect this effect size of parameters between males and females on mesial and distal sides, with 95% confidence and 80% power, a sample of 62 males and 62 females was required. Accordingly, a sample of 60 patients in each gender group was considered.

Patients included in the study exhibited (1) males and females within the age range of 20–40 years, (2) fully erupted well aligned teeth without any orthodontic anomaly, (3) maxillary anterior sextant (central incisors [CIs], lateral incisors [LIs], and canines [CA]) teeth without any restorations, (4) periodontally healthy patients, characterized by an absence or minimal levels of clinical inflammation in a periodontium with normal support (no attachment or bone loss)[10] which was further substantiated by recording of plaque index (PI)[11] and gingival index (GI)[12] wherein the scores were ≤1. Patients with a history or evidence of (1) being under medications for systemic conditions affecting gingival health, (2) periodontal surgery, (3) orthodontic treatment, and (4) presence of artificial crowns or restorations were excluded from the study.

All the included patients were required to undergo Phase I therapy comprising of scaling and root planing along with oral hygiene instructions so as to ensure the clinical condition to be devoid of inflammation if any. After 15 days, on recall, a detailed clinical examination for recording of parameters of PI, GI and presence/absence of papillae was performed.[1314] Study models using alginate irreversible hydrocolloid impression material (Marieflex; Septodont) were prepared for every patient and poured immediately with stone plaster (Neelkanth India Pvt. Ltd.) [Figure 1]. Measurements of the following parameters with digital calliper consisting of liquid crystal display of a size of 6 inch/150 mm and using magnification loupes of 2.5× (SurgiTel; General Scientific) were recorded on study models.

Figure 1

Study model showing the CL, GZP, MPH, DPH. CL - Crown length; GZP - Gingival zenith position; MPH - Mesial papilla height; DPH - Distal papilla height

Crown length and gingival zenith position

CL was recorded as distance from apical most point of free gingival margin to the incisal edge parallel to the long axis. Gingival zenith position (GZP) was the most apical point on scallop of gingival margin.

Papilla height and papilla proportion

The PH on mesial and distal sides of each tooth was recorded as distance from GZP to the tip of papilla [Figure 2]. The mathematical percentage ratio used for calculating PP was PP = PH/CL × 100. This enabled the calculation of MPP and DPP.

Figure 2

Clinical photograph showing CL, GZP, MPH, DPH. CL - Crown length; GZP - Gingival zenith position; MPH - Mesial papilla height; DPH - Distal papilla height

Crestal papilla height and crestal papilla proportion

The crestal PH (CPH) was measured radiographically after the application of radiopaque material on the tip of papilla, similar to the method by Lee et al.[1] The intraoral periapical radiographs with XCP holder (Rinn) using paralleling technique with radiovisiography were taken, and the image was obtained on computer screen. With the computer-aided software device, the CPH was measured as the distance between the radiopaque point and crest of alveolar bone. The mathematical percentage ratio was used to calculate the CPP, i.e., CPP = CPH/CL × 100. On similar lines, the mesial and distal CPPs were calculated [Figure 3]. All the parameters were recorded by the same examiner (AI) who was calibrated prior to the commencement of the clinical trial in a pilot study. A single examiner measured all the clinical and radiographic parameters and was calibrated by repeating the respective measurements to perform intra-observer reproducibility analysis. Intraclass correlation (ICC) coefficient with a two-way mixed-effects model was obtained for each parameter. The ICC ranged between 0.92 and 0.99 in the groups (P < 0.0001), indicating excellent intraobserver reliability.

Figure 3

Radiovisiographic image used with paralleling technique of CI and LI. Arrows indicate the measurements of the distance from alveolar crest to papilla tip between right LI-CI, CI-CI, and left CI-LI. CI - Central incisor; LI - Lateral incisors

Statistical analysis

Descriptive statistics like mean, standard deviation were obtained for the parameters PH, PP, CPH and CPP according to tooth type, mesial and distal sides and for each gender type. The assumption of normality of above parameters was ascertained using Shapiro–Wilk's lambda test. The paired t-test was used to compare the mean difference of parameters between mesial and distal sides for each tooth type. The analysis was performed independently for males and females. Moreover, the comparison of parameters was also performed between males and females according to side using independent sample t-test. All the analyses were performed using SPSS version 20.0 (IBM Corp., Armonk, NY, USA) software, and the statistical significance was tested at 5% level.

RESULTS

The mean mesial and distal PH (MPH and DPH) and CPH sorted as per individual tooth position are presented in Table 1. On comparison of the PH on mesial and distal surfaces, the MPH was found to be consistently greater than DPH in both the genders. Though the differences in MPH and DPH for all teeth have not attained statistical significance, however, teeth numbers 13, 23 in males and 13, 12, 11, and 21 in females showed statistically significant differences. Similar observation was noted for mesial CPH (MCPH) and distal CPH (DCPH) indicating greater values for MCPH over DCPH.

Table 1

Comparison for papilla height and crestal papilla height between two sides of tooth according to gender (n=60)

Tooth number	Males						Females
	PH			CPH			PH			CPH
	Mesial, mean±SD (mm)	Distal, mean±SD (mm)	P*	Mesial, mean±SD (mm)	Distal, mean±SD (mm)	P*	Mesial, mean±SD (mm)	Distal, mean±SD (mm)	P*	Mesial, mean±SD (mm)	Distal, mean±SD (mm)	P*
13	4.38±0.31	4.22±0.24	0.001 (S)	4.93±0.32	4.67±0.24	<0.0001 (S)	4.62±0.29	4.49±0.32	0.007 (S)	5.27±0.29	5.08±0.32	<0.0001 (S)
12	3.93±0.44	3.86±0.60	0.327 (NS)	4.23±0.44	4.21±0.59	0.759 (NS)	4.02±0.40	3.94±0.41	0.038 (S)	4.32±0.38	4.28±0.40	0.264 (NS)
11	4.84±0.35	4.72±0.39	0.084 (NS)	5.49±0.35	5.37±0.38	0.083 (NS)	4.91±0.28	4.80±0.26	<0.0001 (S)	5.64±0.31	5.41±0.34	<0.0001 (S)
21	4.81±0.42	4.71±0.39	0.233 (NS)	5.46±0.41	5.36±0.39	0.233 (NS)	4.92±0.37	4.81±0.31	0.001 (S)	5.65±0.37	5.38±0.30	<0.0001 (S)
22	3.84±0.63	3.73±0.57	0.226 (NS)	4.14±0.63	4.08±0.56	0.509 (NS)	3.95±0.30	3.89±0.38	0.273 (NS)	4.37±0.31	4.29±0.38	0.114 (NS)
23	4.35±0.29	4.25±0.21	0.017 (S)	4.85±0.29	4.70±0.22	0.001 (S)	4.57±0.31	4.56±0.26	0.826 (NS)	5.27±0.31	5.16±0.28	<0.0001 (S)

*Obtained using paired t-test. P ˂ 0.05 is considered as statistically significant. NS – Not significant; S – Significant; SD – Standard Deviation; n – Number of males/females; mm – Millimeters; P – Probability of occurrence; PH – Papilla height; CPH – Crestal pailla height

Gender-based comparison of MPH and DPH revealed that for 13 and 23 the differences in PH were statistically significant. The MPH for males in 13 and 23 teeth was 4.38 ± 0.31 mm and 4.35 ± 0.29 mm, while these values for females were 4.62 ± 0.29 mm and 4.57 ± 0.31 mm, respectively. Similar trend was seen for the LI and CI teeth. For DPH, the mean values were 4.22 ± 0.24 mm and 4.25 ± 0.21 mm for males while for females these were 4.49 ± 0.32 mm and 4.56 ± 0.26 mm respectively and the differences were statistically significant. CPH indicated more significant differences for MPCH between male and female participants with the latter exhibiting greater values in almost all teeth types except 12. For DCPH, the overall mean values for females were greater than male counterparts, but statistical significance was achieved for 13 and 23 teeth only [Table 2].

Table 2

Comparison for papilla height and crestal papilla height between gender according to two side of tooth (n=60)

Tooth number	PH						CPH
	Mesial			Distal			Mesial			Distal
	Males, mean±SD (mm)	Females, mean±SD (mm)	P Ŧ	Males, mean±SD (mm)	Females, mean±SD (mm)	P Ŧ	Males, mean±SD (mm)	Females, mean±SD (mm)	P Ŧ	Males, mean±SD (mm)	Females, mean±SD (mm)	P Ŧ
13	4.38±0.31	4.62±0.29	<0.0001 (S)	4.22±0.24	4.49±0.32	<0.0001 (S)	4.93±0.32	5.27±0.29	<0.0001 (S)	4.67±0.24	5.08±0.32	<0.0001 (S)
12	3.93±0.44	4.02±0.40	0.258 (NS)	3.86±0.60	3.94±0.41	0.412	4.23±0.44	4.32±0.38	0.235 (NS)	4.21±0.59	4.28±0.40	0.496 (NS)
11	4.84±0.35	4.91±0.28	0.257 (NS)	4.72±0.39	4.80±0.26	0.174	5.49±0.35	5.64±0.31	0.016 (S)	5.37±0.38	5.41±0.34	0.526 (NS)
21	4.81±0.42	4.92±0.37	0.125 (NS)	4.71±0.39	4.81±0.31	0.138	5.46±0.41	5.65±0.37	0.006 (S)	5.36±0.39	5.38±0.30	0.829 (NS)
22	3.84±0.63	3.95±0.30	0.220 (NS)	3.73±0.57	3.89±0.38	0.074	4.14±0.63	4.37±0.31	0.011 (S)	4.08±0.56	4.29±0.38	0.018 (S)
23	4.35±0.29	4.57±0.31	<0.0001 (S)	4.25±0.21	4.56±0.26	<0.0001 (S)	4.85±0.29	5.27±0.31	<0.0001 (S)	4.70±0.22	5.16±0.28	<0.0001 (S)

Ŧ Obtained using independent t-test. P ˂ 0.05 is considered as statistically significant. NS – Not significant; S – Significant; SD – Standard deviation; n – Number of males/females; mm – Millimeters; P – Probability of occurrence; PH – Papilla height; CPH – Crestal pailla height

The descriptive statistics for PP according to tooth number and sides for both genders are given in Table 3. In males, the mean difference of PP between mesial and distal sides was found to be statistically significant for 13 and 23 with corresponding values of P = 0.001 and P = 0.022. In females, mean differences was significant for 13, 12, 11, and 21 with corresponding P = 0.007, P = 0.045, P < 0.0001, and P = 0.001, respectively. The mean PP for mesial side was higher than distal in both genders. With regards to CPP in males, the difference in mean values between mesial and distal sides was significant for 13 and 23 displaying P < 0.0001 and P = 0.001, respectively. In females, the mean difference for 13, 11, 21, and 23 was statistically significant. The overall observation indicated higher values for mesial CPP (MCPP) than distal CPP (DCPP) for both the gender [Table 3].

Table 3

Comparison for papilla proportion and crestal papilla proportion between two sides of tooth according to gender (n=60)

Tooth number	Males						Females
	PP			CPP			PP			CPP
	Mesial, mean±SD (mm)	Distal, mean±SD (mm)	P*	Mesial, mean±SD (mm)	Distal, mean±SD (mm)	P*	Mesial, mean±SD (mm)	Distal, mean±SD (mm)	P*	Mesial, mean±SD (mm)	Distal, mean±SD (mm)	P*
13	43.21±4.10	41.66±4.28	0.001 (S)	48.64±4.44	46.10±4.61	<0.0001 (S)	44.96±3.90	43.68±4.09	0.007 (S)	51.27±4.15	49.41±4.36	<0.0001 (S)
12	42.41±5.07	41.75±7.08	0.368 (NS)	45.70±5.19	45.54±7.08	0.817 (NS)	44.01±3.38	43.19±3.83	0.045 (S)	47.44±3.70	46.96±4.56	0.303 (NS)
11	44.58±3.35	43.46±4.35	0.090 (NS)	50.57±3.51	49.45±4.57	0.090 (NS)	47.17±3.22	46.10±3.17	<0.0001 (S)	54.21±3.76	51.97±4.02	<0.0001 (S)
21	44.79±5.12	43.88±4.33	0.197 (NS)	50.85±5.33	49.94±4.64	0.197 (NS)	47.39±4.84	46.35±4.41	0.001 (S)	54.63±6.81	51.97±6.18	<0.0001 (S)
22	42.64±8.11	41.38±7.30	0.211 (NS)	45.96±8.25	45.27±7.35	0.483 (NS)	43.47±3.71	42.77±4.08	0.229 (NS)	48.14±3.97	47.18±4.26	0.089 (NS)
23	43.44±5.14	42.52±4.85	0.022 (S)	48.44±5.58	47.02±5.33	0.001 (S)	44.44±3.76	44.33±3.35	0.828 (NS)	51.27±3.98	50.17±3.71	0.025 (S)

*Obtained using paired t-test. P ˂ 0.05 is considered as statistically significant. NS – Not significant; S – Significant; SD – Standard deviation; n – Number of males/females; mm – Millimeters; P – Probability of occurrence; PP – Papilla proportion; CPP – Crestal pailla proportion

Comparison of MPP, DPP, MCPP, and DCPP between genders, values for the parameters were greater for females than males on both the mesial and distal aspects [Table 4]. The difference amongst the gender for these parameters was seen to be more robust as compared to the PH or CPH.

Table 4

Comparison for papilla proportion and crestal papilla proportion between gender according to two side of tooth (n=60)

Tooth number	PP						CPP
	Mesial			Distal			Mesial			Distal
	Males, mean±SD (mm)	Females, mean±SD (mm)	P Ŧ	Males, mean±SD (mm)	Females, mean±SD (mm)	P Ŧ	Males, mean±SD (mm)	Females, mean±SD (mm)	P Ŧ	Males, mean±SD (mm)	Females, mean±SD (mm)	P Ŧ
13	43.21±4.10	44.96±3.90	0.018 (S)	41.66±4.28	43.68±4.09	0.009 (S)	48.64±4.44	51.27±4.15	0.001 (S)	46.10±4.61	49.41±4.36	<0.0001 (S)
12	42.41±5.07	44.01±3.38	0.044 (S)	41.75±7.08	43.19±3.83	0.170 (NS)	45.70±5.19	47.44±3.70	0.037 (S)	45.54±7.08	46.96±4.56	0.191 NS)
11	44.58±3.35	47.17±3.22	<0.0001 (S)	43.46±4.35	46.10±3.17	<0.0001 (S)	50.57±3.51	54.21±3.76	<0.0001 (S)	49.45±4.57	51.97±4.02	0.002 (S)
21	44.79±5.12	47.39±4.82	0.005 (S)	43.88±4.33	46.35±4.41	0.003 (S)	50.85±5.33	54.63±6.81	0.001 (S)	49.94±4.64	51.97±6.18	0.044 (S)
22	42.64±8.11	43.47±3.71	0.470 (NS)	41.38±7.30	42.77±4.08	0.202 (NS)	45.96±8.25	48.14±3.97	0.067 (NS)	45.27±7.35	47.18±4.26	0.084 (NS)
23	43.44±5.14	44.44±3.76	0.229 (NS)	42.52±4.85	44.33±3.35	0.019 (S)	48.44±5.58	51.27±3.98	0.002 (S)	47.02±5.33	50.17±3.71	<0.0001 (S)

Ŧ Obtained using Independent t-test. P ˂ 0.05 is considered as statistically significant. NS – Not significant; S – Significant; SD – Standard deviation; n – Number of males/females; mm – Millimeters; P – Probability of occurrence; PP – Papilla proportion; CPP – Crestal pailla proportion

DISCUSSION

A pleasing smile is considered an inseparable component of facial esthetics and is gaining increased importance in the practice of contemporary times, specifically in patients seeking treatment to augment their smiles.[315] The IDP, their presence or absence are of great concern for the clinician and have been influenced by form, size, and position of clinical crown, contact point/area, and embrasure space dimensions. Investigators have proposed several guidelines in order to establish appropriate contours and papilla forms in their pursuit toward designing esthetic smiles.[161718]

The mean MPH values were greater than mean DPH values in both males and females. These findings are not in agreement in totality with those observed by Chu et al.[6] and our previous clinical trial,[17] as in the present trial, MPH was found to be uniformly greater in all the teeth. The differences in these observations could be because both the above-mentioned trials were conducted on a nonuniform study population. The former trial was conducted on only 20 patients with no age and sex segregation, while the latter trial had a study population which was heavily biased towards female participants. The present study taking into consideration these discrepancies, formulated uniformity in age and gender of the study population. Though the MPH was consistently greater than DPH, the differences in mean values reached statistical significance only with the bilateral CA in males, while for the female participants, the differences were significant in majority of the teeth.

This is perhaps the first trial incorporating gender-based evaluation of the respective study parameters. Both the MPH and DPH revealed higher values for female patients when compared to the male counterparts. The gender-based differences can be attributed to the fact that the female patients have a predominance of triangular crown morphology while the males exhibit more of square crown forms.[1419] The above observation indicates longer clinical crowns in females, and under normal periodontal conditions will reflect into greater heights of the papillae. Certain variations in the above findings are however possible due to varied anatomical profiles based on bone anatomy.[20] The PHs recorded in the present clinical trial confirm with the range of 4.5–5.5 mm as reported by Spear.[21]

For the evaluation of proportionate presence of soft-tissues and the clinical crown, the mathematical equation of PP takes into account the CL variability. In the present study, the MPP for all the teeth in both the gender was found to be greater than the DPP. The mean values of MPP were found to be maximum for CI, followed by CA, and the least were observed for the LI, thereby indicating a slight curvilinear presentation of the gingival tissues in the IDP tip region. Although the differences between MPP and DPP amongst males were evident, the mean values except for CA did not achieve statistical significance. On the contrary, and similar to the PH in females, all the teeth showed greater MPP than DPP, and the differences were statistically significant in majority of the teeth. These variations could again be considered for the greater tooth length and PH which is seen in female patients. Hence, these findings would logically imply a greater tendency toward gingival recession and periodontal disease which is associated in females as compared to the males.[2223]

The CPP is a comparatively new parameter which determines the length of IDP relative to the crest of alveolar bone. The CPH followed a similar trend to the PH in terms of exhibiting higher mean values on mesial aspect as compared to the distal aspect of each tooth. Though the DCPH was less than MCPH, the differences did not attain significance. However, when these parameters were compared based on gender, the MCPH and DCPH were more pronounced in females than in the males. This could be related to the pronounced scalloped bony and the corresponding soft-tissue architecture exhibited predominantly in females.[2425] Even though the range of MCPH and DCPH was a little higher than the previously reported investigation,[17] all the patients exhibited the presence of IDP as per the mandate of inclusion criteria. Furthermore, this value range was a little lesser than reported by Lee et al.[1] The differences in findings could be related to the differences in interradicular distances and tooth shapes. The findings of the present study appear to be comprehensive and appropriate as the participants included were periodontally healthy, equally segregated as per the age group and gender, thus reducing the chances of undue variations.

On comparison of the PPs with CPPs on the mesial and distal aspects in either of the gender, the CPP follows a similar pattern of the soft-tissue parameters. The present study being conducted in a population with specific age range, it could not address the age-related variations, racial and tooth form differences, which could induce minor variations in the observed values of parameters.

CONCLUSION

In attempt to create beautiful smiles, the intricate characteristics of the soft- and hard-tissues need to be considered as guidelines for periodontal, restorative, and implant procedures. It can be concluded from the findings of the present study that parameters such as MPH, DPH, MPP, DPP, MCPP, and DCPP can be of great importance in providing these guidelines. The MPH, MPP, and MCPP were observed to be greater than the distal counterparts, and the females exhibit higher values for all the evaluated parameters than the males. The apical positioning of the IDP tip on distal aspects as compared to mesial aspects uniformly from CI to CA would be a clinically relevant parameter in an idealistic beautiful smile.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.