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J Gandhara Med Dent Sci
ORIGINAL ARTICLE
:
:
EVALUATION OF COINCIDENCE OF GINGIVAL ZENITH AND VERTICALLY BISECTED
MIDLINE IN ANTERIOR TEETH: A CROSS-SECTIONAL STUDY
Sharafat Abdullah
1
, Shafqat Hussain
2
, Sana Gul
1
, Sajid Ali
2
, Sana Murtaza
3
, Izazullah
1
ABSTRACT
OBJECTIVES
This study aimed to evaluate the coincidence and displacement of the gingival
zenith in relation to the VBM of maxillary anterior teeth and to examine
possible gender dierences.
METHODOLOGY
A cross-sectional study was conducted with a non-probability consecutive
sampling technique on 100 patients aged 18-30 at the outpatient department
of Rehman College of Dentistry. Maxillary impressions were taken and
poured in type IV dental stone. A digital caliper measured the gingival zenith
and VBM on the casts, along with a pico-coronal displacement of lateral
incisors. Data were analyzed using SPSS v22 with appropriate statistical
tests (Shapiro-Wilk, t-test/Mann-Whitney U, chi-square), with signicance set
at p < 0.05.
RESULTS
With mean shifts of 0.70-0.84 mm and no signicant gender dierences
(parametric eect size d = 0.25-0.35; 95% CI; p>0.05), gingival zenith
displacement was more prevalent in central incisors (>90%). Minor
nonparametric eects were observed in canines and lateral incisors (r <
0.081), with canines most aligned with VBM.
CONCLUSION
Displacement of the gingival zenith is common in maxillary anterior teeth,
particularly in central incisors, while canines show the greatest likelihood of
coincidence with the VBM. Gender did not inuence gingival zenith position.
Careful assessment of zenith position is recommended when planning esthetic
dental treatments.
KEYWORDS: Gingival Zenith, Vertically Bisected Midline, Apico-Coronal
Displacement.
How to cite this article
Abdullah S, Hussain S, Gul S, Ali S,
Murtaza S, Izazullah. Evaluation of
Coincidence of Gingival Zenith and
Vertically Bisected Midline in
Anterior Teeth: A Cross-Sectional
Study. J Gandhara Med Dent Sci.
2026;13(1): 44-48.
Date Submission: 30-09-2025
Date Revised: 09-12-2025
Date Acceptance: 15-12-2025
2
Associate Professor, Department of
Prosthodontics, Rehman College of
Dentistry
1
Post Graduate Resident, Department of
Prosthodontics, Rehman College of
Dentistry
3
Demonstrator, Department of
Prosthodontics, Rehman College of
Dentistry
Correspondence
Sharafat Abdullah,
Post Graduate
Resident, Department of Prosthodontics,
Rehman College of Dentistry
+92-316-9463386
shery.sharafat@gmail.com
INTRODUCTION
Beauty is often regarded as a harmonious integration of
features that evoke a sense of balance, admiration, and
aesthetic pleasure. Among the most signicant
contributors to rst impressions are facial appearance
and the quality of one’s smile, both of which can have a
lasting impact.
1
With the increasing emphasis on facial
and dental aesthetics in contemporary society, there has
been a substantial rise in the demand for restorative and
cosmetic dental procedures. An aesthetically pleasing
smile not only improves physical appearance but also
enhances self-esteem and social condence, reinforcing
the role of dental esthetics in overall well-being.
2
Restorations that enhance dental appearance have been
shown to inuence a patient’s self -image positively.
3
The gingiva’s morphology, contour, and health are
critical in determining smile attractiveness, and
irregular gingival form can signicantly aect esthetic
outcome.
4
Therefore, integrating functional and esthetic
elements requires careful consideration of the dento-
gingival interface.
5
Existing literature emphasizes the
significance of the gingival zenith in esthetics. The
gingival line, dened by the connection of zenith points
of the central incisors and canines, plays a pivotal role
in gingival morphology. The zenith, being the most
apical point of the gingival margin, directly aects
tooth inclination and emergence prole.
6
previous
studies have reported variability in the zenith positions
of maxillary anterior teeth. For example, Magne and
Belser identied the zenith of anterior teeth as
displaced from their long axes.
7
While Rufenacht noted
distal placement for central incisors and canines, but
alignment with the tooth axis for lateral incisors.
Studies have further shown that in most cases, the
gingival zenith of central incisors lies distal to the
vertical bisector, with minor gender-related
dierences.
8,9
Other investigations by Chu et al.,
https://doi.org/10.37762/jgmds.13-1.793
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J Gandhara Med Dent Sci
Evaluation of Coincidence of Gingival Zenith and Vertically
Mattos, and Santana reported distal displacement of the
gingival zeniths in canines, with relatively less
displacement in lateral incisors.
10
Similarly, Zagar et al.
demonstrated distal displacement in varying
proportions across central, lateral, and canine teeth.
11
Given the importance of gingival zenith positioning in
achieving esthetic outcomes, further clinical guidelines
tailored to dierent populations are needed, particularly
for use in esthetic restorative procedures where gingival
contours are modied. A study of a Pakistani
population found that distal displacement is more
prevalent in central and lateral incisors.
19
Axial
inclination, emergence prole, and general harmony of
the smile are all inuenced by the gingival zenith,
which is a crucial factor in anterior dental aesthetics.
Significant population-specific dierences have been
documented among ethnic groups, even though the
distal displacement of the gingival zenith in maxillary
anterior teeth is frequently highlighted in international
literature. Gingival zenith behavior in the Khyber
Pakhtunkhwa (KP) region was not explicitly studied
until recently, and there remains a dearth of data in
Pakistan. Distal gingival zenith deviations were
primarily found in the central and lateral incisors, with
age-related increases in deviation, but no gender
dierences, according to the only national-level data
from Pakistan currently available. Although applicable,
this single study does not accurately reect the KP
population.
METHODOLOGY
This cross-sectional study was conducted at the
outpatient department of Rehman College of Dentistry,
RMI Peshawar, from 2022 to 2025, following approval
from RMI and the College of Physicians and Surgeons
Pakistan (CPSP). A sample size of 100 was calculated
using the WHO sample size calculator, with a 95%
confidence level and a 10% margin of error.
11
Participants were selected using a non-probability
consecutive sampling technique. Patients included in
the study were males and females aged 18 to 30 years
with well-aligned maxillary anterior sextants exhibiting
normal gingival contour and structure, who visited the
prosthodontics department of RCD for xed
restorations to improve esthetics and smile. Only
patients with no previous history of orthodontic or
periodontal treatment were included. Exclusion criteria
comprised individuals with evidence of tooth alterations
such as traumatic injury, occlusal wear, or cervical
abrasion, as assessed by history, clinical examination,
and radiographs. Patients with gingival alterations,
including hyperplasia, inammation, attachment loss,
gingival recession, or a history of periodontal surgery,
were also excluded. Further exclusions were applied to
those with missing anterior teeth, crowding, a history of
orthodontic or prosthodontic treatment, and diastema,
as determined clinically and radiographically. The
patients were informed of the study’s advantages and
goals, and verbal informed consent was obtained.
Participants were stratied by biological gender (male,
female) to assess potential gender-related dierences in
gingival zenith position; the sample included 50 males
and 50 females. Gender comparisons were treated as
secondary analyses; the study was primarily powered to
estimate the prevalence and magnitude of gingival
zenith displacement in the overall sample. Data were
analyzed in the statistical programme SPSS (version
22). A maxillary arch imprint was taken using cavex
cream alginate (CAVEX HOLLAND), and type IV
dental stone was poured into the impression to create a
stone cast. Inter-observer variability did not apply
because all measures were obtained by a single,
qualied examiner using a calibrated digital caliper and
a dened technique. Consistency was maintained
through repeated landmark verication, using the same
measurement methodologies throughout and according
to established protocols used in prior gingival zenith
morphometric research. The tooth width was measured
at two reference positions with a digital caliper to
determine the vertically bisected midline (VBM) of
each clinical crown on the cast. The reference positions
were the proximal incisal contact point and the apical
contact point. The center point of each width‘s division
into halves was noted. To determine the vertically
bisected midline, the center points were stretched along
a line toward the gingival side of the clinical crown.
The most apical point on the free gingival margin is
used to determine the gingival zenith for each tooth, as
shown in Figure 1. The gingival zenith, or its
displacement from midline, was noted. A tangent line
(gingival aesthetic line) was drawn on the diagnostic
castings from the gingival zenith positions of the central
incisor and canine on the ipsilateral sides, and the
distance of the lateral incisor zenith in an apical-coronal
direction was noted
as shown in Figure 2.
18
Figure 1: Determination of Vertically Bisected Midline (VBM)
and Gingival Zenith Point (GZ), Apical Contact Area Point
(ACAP), Incisal Contact Area Point (ICAP)
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J Gandhara Med Dent Sci
Evaluation of Coincidence of Gingival Zenith and Vertically
Figure 2: Determination of The Gingival Aesthetic Line
RESULTS
Normality of the data was assessed using the Shapiro-
Wilk test, which indicated that measurements of the
right and left central incisors were normally distributed
(p > 0.05). In contrast, measurements of the lateral
incisors and canines for both genders showed
significant deviation from normality (p < 0.001). Mean
and standard deviation were reported for data normally
distributed, and median [IQR] was reported for non-
distributed data. Comparison of outcomes was analyzed
by applying the Independent t-test/ Mann–Whitney U
test. The chi-square test analyzed the frequency of
coincidence. The analysis of gingival zenith positions at
a 95% condence interval in the anterior sextant
revealed no statistically signicant gender dierences
across all teeth (p > 0.05). Overall, gingival zenith
positions showed a tooth-dependent trend: central
incisors were the most displaced, with right and left
central incisors’ eect size (Cohen’s d ranging from
0.25 to 0.35) showing minimal to moderate gender-
based dierences, and canines showed the highest
tendency for coinciding zeniths. While lateral incisors
and canines showed nonparametric size eects of 0.081
and 0.02, respectively, supporting the conclusion that
gender dierences are negligible. Apico-coronal
displacement of the lateral incisors was minimal and
comparable between genders.
Table 1: Shapiro-Wilk Normality Test for Gingival Zenith
Measurements
Tooth Gender P-Value
Right Central Incisor Male 0.138
Female 0.090
Left Central Incisor Male 0.072
Female 0.007
Right Lateral Incisor Male 0.000
Female 0.000
Left Lateral Incisor Male 0.000
Female 0.000
Right Canine Male 0.000
Female 0.000
Left Canine Male 0.000
Female 0.000
Table 2: Descriptive Statistics for Gingival Zenith in Anterior
Sextant
Tooth Gender Mean±SD/Median
(IQR)(mm)
P-value
Right Central
Incisor (UR1)
Male 0.71 ± .40 mm 0.22
Female 0.81±.40 mm
Left Central
Incisor (UL1)
Male 0.70± .41 mm
0.08
Female 0.84± .41 mm
Right Lateral
Incisor (UR2)
Male 0.20 (.60) mm
0.41
Female 0.30 (.52) mm
Left Lateral
Incisor (UL2)
Male 0.700 (.50) mm
0.84
Female 0.80 (.40) mm
Right Canine
(UR3)
Male 0.10 (.42) mm
1.0
Female 0.05 (.32) mm
Left Canine
(UL3)
Male 0.10 (.22) mm
0.83
Female 0.05 (.33) mm
Table 3: Apico-Coronal Displacement of Lateral Incisors by
Gender
Tooth Gender Median (IQR)
(mm)
P- value
Right Lateral
Incisor (UR2)
Male 1.10 (0.20) mm 0.83
Female 1.10 (0.40) mm
Left Lateral
Incisor (UL2)
Male 1.20 (0.40) mm 0.52
Female 1.20 (0.32) mm
Table 4: Frequency of Coinciding vs Displaced Zenith Points by
Gender
Tooth Gender Coinciding
(n, %)
Displaced
(n, %)
P-
value
Right
Central
Incisor(UR1)
Male 3, 6 % 47, 94% 0.93
Female 3, 6% 47, 94%
Left Central
Incisor(UL1)
Male 2, 4% 48, 96% 0.76
Female 1, 2% 49, 98%
Right Lateral
Incisor(UR2)
Male 17, 34% 33, 66% 0.92
Female 12, 24% 38, 76%
Left Lateral
Incisor(UL2)
Male 13, 26% 37, 74% 0.89
Female 16, 32% 34, 68%
Right Canine
(UR3)
Male 22, 44% 28, 56% 0.97
Female 25, 50% 25, 50%
Left Canine
(UL3)
Male 20,40% 30, 60 % 0.72
Female 25, 50 % 25, 50 %
DISCUSSION
This study examined the positional association between
the gingival zenith and the vertically bisected midline
(VBM) in maxillary anterior teeth. The ndings
demonstrated that the gingival zenith did not align with
the VBM in most cases, though no statistically
significant gender dierences were identied (p >
0.05). These results reect the natural variability of soft
tissue and dental midline alignment, underscoring the
importance of individualized evaluation during esthetic
treatment planning, particularly in smile design and
anterior restorations. In this study, the gingival zenith
consistently showed distal positioning relative to the
anterior teeth, consistent with the results of Felipe V.
12
Central incisors exhibited the lowest rates of
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J Gandhara Med Dent Sci
coincidence (2-6%), whereas lateral incisors
demonstrated moderately higher coincidence (24-32%).
Canines displayed the highest coincidence rates (40-
50%), indicating a more balanced distribution of zenith
placement. These results are consistent with previous
studies, such as those by Mattos and Santana, who
reported distal zenith displacement across canines,
laterals, and centrals in varying proportions.
13
Despite
dierences among tooth types, tooth shapes, and
gingival biotypes, no statistically signicant gender
dierences were found, aligning with reports from
Appukuttan et al. and Chu et al., showing
displacements between 0.7 and 1.2 mm.
14,15
Apico-
coronal displacement of lateral incisors showed no
gender-specic dierences, with consistent median
values, comparable to ndings by Gaddale.
16,17
The
clinical relevance of understanding zenith positioning
lies in its impact on tooth proportion, gingival contour,
and overall smile harmony. Ideally, central incisors and
canines exhibit zeniths slightly distal to the VBM,
while lateral incisors typically align with it, creating
natural gingival curvature and symmetry. Deviations
from these norms may compromise esthetic outcomes
in smile design and restorative procedures. These
results are consistent with earlier research showing that
gingival architecture is subject to signicant inter-
individual variability even within the same
demographic group, suggesting that individual
anatomical factors may strongly inuence biological
variability in gingival form than by gender. The
gingival biotype, which varies in thickness, shape, and
recession susceptibility, may be a signicant biological
cause for this heterogeneity. While thinner biotypes are
associated with increased scalloping and apical
migration of the zenith, thicker, brotic biotypes often
exhibit more stable, less scalloped gingival edges. The
small magnitude of displacement dierences between
genders indicates that biotype distribution may be
relatively similar between male and female patients in
this population, even though biotype was not directly
measured in this study. Clinically, these results imply
that gender-based assumptions are not justied when
planning esthetic restorations or gingival recontouring
in the anterior maxilla. Additionally, localized anatomic
features, such as tooth prominence, root angulation, and
alveolar crest morphology, may be more important than
demographic variables in determining zenith location.
Ignoring patient-specic gingival zenith variability can
result in non-ideal emerging proles, asymmetric
gingival contours, or poor pink-white esthetics in
restorative and implant treatments, particularly in the
esthetic zone. This bolsters arguments for including
gingival zenith assessment into processes for digital
smile design and pre-operative planning.
LIMITATIONS
One of the main strengths of this study is that it
addresses an important aspect of dental esthetics by
systematically evaluating the relationship between the
gingival zenith and the vertically bisected midline in
maxillary anterior teeth. The use of well-defined
inclusion criteria and standardized measurement
methods provided clarity and consistency in data
collection. In addition, the study provides valuable
baseline information for clinicians, particularly for
treatment planning in restorative and esthetic dentistry.
However, several limitations should also be considered.
This was a single-center, cross-sectional study
conducted with a relatively small sample of young
adults aged 18-30 years, limiting the generalizability of
the results to broader populations. The use of
consecutive, non-random sampling may have
introduced selection bias. Measurements were made on
stone casts obtained from alginate impressions, which
are prone to minor dimensional changes, and examiner
calibration or reliability testing was not reported,
leaving room for operator-related variability. Important
clinical variables, such as gingival biotype, smile line,
arch form, and tooth shape, were not evaluated, which
could have inuenced the results. Finally, being cross-
sectional, the study does not provide insight into how
the gingival zenith position may change over time or
following dental treatment. Future studies with larger,
more diverse samples, digital intraoral scanning to
improve accuracy, and longitudinal follow-up are
recommended to build on these ndings and establish
more generalizable clinical guidelines.
CONCLUSIONS
With central incisors exhibiting the most signicant
displacement and canines exhibiting the positional
stability, the gingival zenith seldom aligns with the
vertically bisected midline. Since gender had no
discernible impact, these results highlight the need for
individualized evaluation rather than relying on broad
aesthetic standards. To achieve harmonious gingival
architecture, canines can serve as reliable reference
points in clinical settings. To improve aesthetic
standards, more research using bigger, digitally
evaluated samples is advised.
CONFLICT OF INTEREST: None
FUNDING SOURCES: None
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Sharafat Abdullah - Concept & Design; Data Acquisition;
Data Analysis/Interpretation; Drafting Manuscript; Final
Approval
Shafqat Hussain - Concept & Design; Data Acquisition; Data
Analysis/Interpretation; Drafting Manuscript; Critical
Revision; Supervision; Final Approval
Sana Gul- Concept & Design; Data Acquisition; Drafting
Manuscript; Final Approval
Sajid Ali - Concept & Design; Data Acquisition; Data
Analysis/Interpretation; Drafting Manuscript; Critical
Revision; Supervision; Final Approval
Sana Murtaza - Concept & Design; Data Acquisition; Data
Analysis/Interpretation; Drafting Manuscript; Final Approval
Izazullah - Concept & Design; Data Acquisition; Drafting
Manuscript; Final Approval
AUTHORS CONTRIBUTION
The authors accept responsibility for all aspects of the work
and will ensure that any concerns regarding the accuracy or
integrity of any part are properly investigated and resolved.
Evaluation of Coincidence of Gingival Zenith and Vertically
January - March 2026