Gingival Biotype Variations with Gender in Indian Population Using Direct Visual Inspection, Probe Transparency and Transgingival Probing Technique: A Cross -Sectional Study

Introduction

There are many variations observed in both the genders including physiological, anatomical, biological and biochemical variations. These changes are also observed in oral and dental tissues.¹

Gingiva (gums) is a part of oral mucosa that covers the alveolar process of jaws and surrounds the neck of tooth in a collar like fashion. Gingiva is a keratinized tissue. It is the primary barrier which protects teeth and underlying bone from different microorganisms.² The biotype of gingiva plays an important role in maintenance of oral health as well as planning for any regenerative or restorative treatment. Although functioning is important for long term success, esthetics is also essential.Clinical appearance of gingiva differs in both the genders. It is directly related to periodontal health and prognosis of many dental treatments.

The word “Gingival biotype” was first given by Ochsenbein and Ross.³ They used the term to describe different types of gingival contour. They also reported and suggested that flat gingiva is closely related to square tooth form, while scalloped gingiva is related to tooth form that is tapered.⁴ Then, Seibert and Lindhe introduced the term “periodontal biotype”; they divided the biotype into two categories, the “thick” and “thin”. This was categorized according to the appearance of gingiva on simple visual inspection method.⁵ In 1997, while analysing gingival biotype, Muller introduced some new parameters, such as tooth shape and gingival width.⁶ De Rouck suggested a new method for the classification of gingival biotype. He classified gingival biotype based on the four clinical parameters: gingival thickness, crown width/crown length ratio, gingival width and papilla height. Then, three biotypes were noticed: the thin-scalloped, thick-scalloped and thick-flat biotype.⁷ Claffey and Shanley defined the thin tissue biotype as gingival thickness of <1.5 mm, and the thick tissue biotype was referred to as having tissue thickness ≥2 mm.⁸

Gingival biotype is important in identifying and anticipating the prognosis of treatment outcome. For example, thin biotype may lead to postoperative gingival recession and exposure of the root surface,⁹ graft failure,¹⁰ unpredictable postoperative soft tissue healing, extensive bone resorption after tooth extraction, especially in apical and lingual directions,¹¹ exposure of restorative margins,¹² and mucogingival problems with various orthodontic treatments.¹³ Whereas nonsurgical periodontal therapies in patients with thin biotype are more successful.¹⁴

Various invasive and non-invasive methods have been proposed to measure tissue thickness. These methods include conventional histology on cadaver jaws, injection needles, transgingival probing, histologic sections, cephalometric radiographs, probe transparency, ultrasonic devices, and cone-beam computed tomography.

With this background, the present study was designed to assess the gingival biotype variation in males and females of Indian population by non-invasive visual inspection method and invasively by probe transparency, transgingival probing methosd.

Materials and Methods

This was a cross sectional study involving 200 subjects (100 males and 100 females) who were randomly selected from general population.

Inclusion criteria

• Subjects with healthy periodontium

• Subjects with absence of any attachment loss or gingival recession

Exclusion criteria

• Subjects who were on drugs such cyclosporin A, calcium channel blockers, and phenytoin (since they cause changes in periodontal tissues)

• Subjects who were diabetic or who were on antihypertensive drugs (since they cause changes in periodontal tissues)

• Subjects who were pregnant or lactating

First method for inspection of gingival biotype was visual method, that is by looking at the gingiva one determines whether the gingiva is thick or thin (Figure 1). Second method was probe transparency method. In this, a UNC‑15 periodontal probe was used to probe the gingival sulcus at the midbuccal aspect of the maxillary incisors to check whether the probe is visible through gingival tissues; then the result was drawn either as thick or thin (Figure 2). The third method performed was invasive method - Transgingival probing. After anesthetizing with lidocaine spray (Nummit 15%), endodontic spreader no. 15 was placed midbuccally with rubber stopper as demonstrated in figure 3 and then was measured on a ruler.

Results

The study sample consisted of 200 subjects which included 100 males and 100 females. Based on the analysis of results, the thick and thin were classified by visual inspection, probe transparency and transgingival probing.

The thick biotype was more prevalent in males, as observed on visual inspection as 67%, 76% with probe transparency method, and 70% with transgingival probing (Table 1, Graph 1). Contrary to this, female population showed thin gingival biotype with 71% on visual inspection, 65% with probe transparency method and 68% with transgingival probing. The p value of Chi square test was found to be significant as shown in table 1 and graph 2.

Discussion

The proportion and extent of both soft tissue and hard tissue plays an important role in predicting the outcome of disease. Gingival biotype is different in different individuals including various age groups, and in males & females. Gingival biotype is directly linked to the diagnosis and prognosis of treatment which includes periodontal flap, mucogingival surgery and implants. This is most importantly observed in the aesthetic region, that is the anteriors. In cases with thin biotype, the outcome of periodontal therapy may result in gingival recession. On the other hand, in cases with thick biotype, deep periodontal pockets may be noticed.¹⁵ Therefore, gingival biotype is a key factor for proper planning of dental and periodontal treatment and predicting the outcome of disease.

Thick and adequate periodontium is directly linked to periodontal health, with adequate attached gingiva. It is flat and suggestive of thick underlying bone.¹⁶ Thick gingival biotype favours better tissue manipulation, allows creeping attachment, reduces clinical inflammation, more resistant to trauma, prevents recession and better prognosis for implant esthetics with a proper biological seal. Whereas thin gingival biotype is translucent and very fragile suggesting thin bone, and therefore can be predictive of osseous defects.¹⁶

There are various methods for assessment of gingival biotype - direct visual assessment, probe transparency method, use of ultrasonic devices or radiographic methods. In this study, we used direct visual assessment method, probe transparency method involving use of periodontal probe within sulcus and transgingival probing using a file.

The results of the present study can be compared to the results of Kan et al.¹⁷ He performed the biotype assessment using periodontal probe transparency method and direct measurement technique and demonstrated that they are statistically same, being reliable and objective. However, the study conducted by Olsson et al.,¹⁶ observed no association between visual and measured gingival tissue forms. Eghbali et al.,¹⁸ also conducted similar study and concluded that only visual inspection cannot a good source for judging the type of biotype. Visual inspection alone is not reliable irrespective of the experience of the clinician.

The results obtained in our study are similar to the findings of De Rock et al.,⁷ and Muller et al.,⁶ who concluded that females had thinner biotype and males showed thicker. Another study by Eghbali et al.,¹⁸ also reported females with thin gingival form which was scalloped and males with broad band of keratinization, thick and flat biotype.

Conclusion

Within the limitations of this study, one can draw the following three conclusions:

1. Combination of methods used to evaluate the gingival biotype gives us a better understanding of the biotype and the results are almost similar.

2. The current study demonstrated the existence of two main gingival biotypes – thick and thin.

3. An objective test with visual examination, probe transparency method and transgingival probing technique has been shown in the current study.

However, long term studies with larger sample size must be undertaken for a definitive conclusion.

Conflict of Interest

None