Introduction

Gingival black triangle (GBT) results from loss of interdental papilla and it is a very important component in an aesthetic and ideal smile (Burke, Burch, & Tetz, 1994; Cho, 2006; Takei, Yamada, & Hau, 1989). GBT does not only play a role in aesthetic concerns but also may cause plaque accumulation and phonetic problems (Takei, 1980).

It was found in a study done by (Kokich, 1999) that people with GBT more than 3mm were found to be less attractive (Cho, 2006; Tarnow, 2003). According to a survey done, it was found that GBT is the most disliked aesthetic concern after caries and exposed crown margins. There are many studies showing the occurrence of GBT post orthodontic treatment in the upper anterior teeth, mainly central incisions (Houston, 1984; Newman, 2011).

Also previously published studies state that prevalence of black triangle amongst adults over 20 years of age was found to be 67% and that of the individuals below 20% of age was 18% (Ahmad, 2005; Ko-Kimura, 2003; Zetu & Wang, 2005).

Major difficulties in the management of GBT's are because of the limited blood supply to the papilla. (Cunliffe & Pretty, 2009; Ramesh, Ravi, & Kaarthikeyan, 2017; Ravi, 2017) This is the reason for inconsistencies in the management of GBT's in clinicians.

The outcome of the GBT management is highly unpredictable due to the limited blood supply; also, the procedure requires a high skill set; there is also a high chance of recession post-treatment. (Mahendran, 2017; Varghese, 2015).

The aim of the study was to calculate the prevalence of Gingival Black Triangles (GBT’s) in Young Adults in the Chennai Population and correlating with the other causative factors.

Materials and Methods

This is a single university based assessment study which was carried out in saveetha dental college and hospital Chennai. Patient records were reviewed for the period between June 2019 to March 2020, and 149 case records were randomly selected. A retrospective analysis was done for the randomly collected data records. Inclusion exclusion criteria were strictly followed during data selection. Inclusion and exclusion criteria were as follows.

Inclusion criteria

• Complete dias record/case history

• Patient with informed consent

• Patients with HD photographic records

• Systematically healthy patients

• Patients with no history of any procedure which might cause gingival recession, e.g. periodontal flap surgery

• Patients without any history of GBT correction procedures.

• Patients with periodontal chart and records

Exclusion criteria

• Incomplete photographic record.

• Patients on medications mentioned above.

• Patients with the systemic condition.

Parameters Assessed

Primary parameter

Gingival Black triangle (Presence or absence)

Secondary parameters

• Morphology of the tooth

• Labial frenal attachment

• Probing depth

Aetiology of GBT’s

Detailed and well-documented studies are available to prove that aetiology of GBT is multifactorial rather than being caused by a single abnormality. Some of the factors are as follows, (Chang, 2007; Nemcovsky, 2001; Velden, 1984)

• Morphology of teeth. (Alani, Maglad, & Nohl, 2011; Lee, 2016; Sharma & Park, 2010)

• Patients age

• Gingival biotype

• Improper tissue handling

• Bone loss

• Divergent roots which follow orthodontic treatment.

• Inter proximal space etc. (Arellano & Buendía, 2018)

Amount of interproximal space is directly related to viability and blood supply of the papilla. On the one hand, wider space may facilitate increased blood supply, but it can also cause GBT due to stretching out the papilla. Martegani et al. (2007) studied the measurement of interproximal width with periapical radiographs; (Ramesh, 2019) The statistical analysis concluded that when inter radicular distance is more than 2.4 mm the presence of a complete viable papilla without a GBT becomes less likely. (Kavarthapu & Thamaraiselvan, 2018; Priyanka, 2017; Ramamurthy & MG, 2018)

Classification

GBT's Classifications were given by 1) Nordland and Tanrow et al. 2) Nemcousky (a) Photographic data of all the patients who were included in the study was acquired and only the intraoral frontal photos (high definition clicked with DSLR) were assessed for the presence of gingival black triangle this study was done after getting approval from ethical comily of SDC.

STATISTICAL ANALYSIS

IBM SPSS version 20 was used to statistically analyse the collected data for the prevalence of Gingival black triangles (GBT's). Chi-square test and Pearson correlations for tooth morphology, labial frenal attachment and probing depth in the occurrence of GBT's were also analysed in the study population.

Results and Discussion

After assessment of 149 selected samples, it was found that prevalence of gingival black triangles (GBT's) in the young population (18-30 yrs) in the selected study population is 20.8% 31 out of 149 selected subjects had gingival black triangle (Figure 1). No statistical significance was found between the subsets of the tooth morphology, labial frenal attachment and probing depth in the occurrence of GBT’s in the study population.

From Figure 2, The X-axis represents groups where the gingival black triangle is Present and Absent. Y-axis represents the number of individuals falling into each group based on tooth morphology. The subsets of Tooth Morphology categories whose proportions do not differ significantly from each other at the .05 level (Pearson Chi-Square Value - 62.283).

From Figure 3, The X-axis represents groups where the gingival black triangle is Present and Absent. Y-axis represents the number of individuals falling into each group based on the level of frenal attachment. The subsets of Frenal Attachment Level categories whose proportions do not differ significantly from each other at the .05 level (Pearson Chi-Square Value - 29.263).

From Figure 4, The X-axis represents groups where the gingival black triangle is Present and Absent. Y-axis represents the number of individuals falling into each group based on probing depth at the mesial line angle of central incisors (tooth numbers -11, 21). The subsets of Probing Depth categories whose proportions do not differ significantly from each other at the .05 level (Pearson Chi-Square Value - 2.332).

Gingiva follows the underlying bone level to maintain the biological width of the structure. Reduction in the bone level is followed by the gingival recession, which in turn results in an open embrasure space. In periodontal conditions where the bone level is lost in at the line angles of anterior teeth the interdental papilla tends to recede to the new bone level this can be related to increased probing depth causing open embrasure space. No significance was found in the present study between probing depth and presence of gingival black triangle as most of the screened patients were found to be periodontally healthy as there was no increased probing depth.

Loss of interdental papilla causes the condition known as Gingival black triangle. It is one of the most important features which patients and clinicians should pay attention specially because it plays an important role in aesthetics and ideal smile. The labial frenum is the ligament found it attached to the gingiva between two upper central incisors, and its attachment level can be variable. Even though not a prompt causative factor but labial frenum when attached at a lower lever (papillary and papilla penetrating) definitely worsens the condition due to continuous pressure on the papilla. (McCoy, 1935) Level of frenal attachment is not considered as an absolute cause for the condition, results of the correlation between gingival frenal attachment and present of the gingival black triangle were found non-significant (Figure 3). Tooth morphology plays an important role in the presence of probing depth. Central incisors falling into the category of tapering morphological form have a higher prevalence of gingival black triangle as the contact point is more coronal and embrasure space is wider. (Dibiase, 2006)

The gingival black triangle is a multifactorial condition. The use of molecular biomarkers to diagnose periodontal disease is evident in periodontal research; however, there is a lack of evidence pertaining to the role of the prevalence of gingival black triangles and periodontal disease. Tooth morphology was also one of the causative agents of the gingival black triangles. Square, tapering or Ovoid shaped teeth result in a shift of the contact area towards the incisal or occlusal surface which results in broadening of the contact area and can be a cause for the black triangle occurrence. These cases are treated orthodontically along with IPR- interproximal stripping (Khalid, 2017; Mootha, Malaiappan, Jayakumar, Varghese, & Thomas, 2016; W Khalid et al., 2016). There was no statistically significant difference found in the results of the distribution of different tooth morphology in the cause of black triangles (Figure 2). (Avinash, Malaippan, & Dooraiswamy, 2017; Panda, 2014; Thamaraiselvan, Elavarasu, Thangakumaran, Gadagi, & Arthie, 2015).

When assessing a case of GBT's for papillary reconstruction procedure, it is very important to not only to assess the etiology of the GBT but also to observe crest of the bone and apical point of the immediate contact area, along with soft tissue height in the contact area. (Hawkins, Virani, & Ceconi, 2013).

A study done by tanrow has become the gold standard to calculate the distance between the crestal bone contact point. His study based on 288 patients showed that when the contact area was within 5mm from the crest of the alveolar bone, the papilla was present in 100% of the patients. However, when the distance was 7mm, the papilla was only present in 27% of the patients. Wa YJ et al. also found similar results in his study. (Jesylne, Soundarajan, Murthykumar, & Meenakshi, 2016; Murthykumar, 2015; Singh, Uppoor, & Nayak, 2013)

According to a study done by Kurth and Kokich et al., the prevalence of gingival black triangles was found to be one-third of the selected population. Findings of the current study show similar results. (Kurth & Kokich, 2001; Ramesh, Varghese, Jayakumar, & Malaiappan, 2016)

Very few studies have been done to calculate the prevalence of gingival black triangles in any selected population, hence this study enables us to calculate the prevalence of GBT'S in the selected population and will allow us to spread awareness of possible treatment modalities in the areas of high density. (A Ramesh et al., 2016)

LIMITATIONS

Limitations of the study are as follows:

• As it is a single university based sampling study setting infers that patients from only specific regions in Chennai.

• It was a convenience sampling also selection and assessment bias had to be taken into consideration as it.

• All the samples were assessed by a single operator.

FUTURE SCOPE OF THE STUDY

As proven in many of the studies, GBT is one of the most important criteria in gingival aesthetics, and most of the patients are unaware of its causes, presence or possible treatment modalities to treat them. With the help of such studies, we can find out areas of a high prevalence of the GBTS's and spread awareness in such areas.

Conclusion

Within the limits of this study, it was found that prevalence of gingival black triangles in a young adult population in Chennai population is 20.8 % further studies with higher sample size and wider screening zones have to be done.

Conflict of Interest

The authors declare that they have no conflict of interest for this study.

Funding Support

The authors declare that they have no funding support for this study.