Gingival Biotype Assessment in relation to varying tooth form – A Cross Sectional Study

 

Swapna B V¹, Sheetal Shetty², Smitha S Shetty³

¹Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Melaka Manipal Medical College, Manipal-576104, Karnataka.

²Assistant Professor, Department of Conservative Dentistry and Endodontics, Faculty of Dentistry, Melaka Manipal Medical College, Manipal-576104, Karnataka.

³Associate Professor, Department of Oral Pathology, Faculty of Dentistry, Melaka Manipal Medical College, Manipal-576104, Karnataka.

 

ABSTRACT:

The role of gingival tissue in restorative dentistry is important in harmonizing esthetics and biological function. Gingival biotypes have been stated to be thick or thin. Patients with thin biotype are more susceptible to recession, inflammation, and compromised soft tissue response. The correct identification of gingival biotypes is important for the treatment of planning process in restorative and implant dentistry. The purpose of the study was to evaluate the prevalence of different biotypes in individuals with varying forms of maxillary central incisors. A total of 150 students with age range of 18-21 years participated in the study.  Clinical parameters including the papillary height, crown width/length ratio of the central incisors and gingival thickness were recorded by one examiner. The measurements were tabulated and evaluated. Females had thinner biotypes and short, wider form of maxillary central incisors. and males exhibited thicker biotype with long, narrower forms of maxillary central incisors.

 

 

 

INTRODUCTION:

Current trend in aesthetic dentistry is emphasizing more on the gingival perspective for harmonizing aesthetics along with function. Identification of the gingival morphology is considered necessary because alterations in soft and hard tissue architecture have shown to exhibit a major impact on the final esthetic outcome of restorative and periodontal procedures and implant esthetics.¹ Periodontal biotype assessment is an important component in the diagnostic and prognostic phase of treatment.²

 

 

The influence of gingival thickness has been documented in various applications including non-surgical periodontal therapy, mucogingival therapy, guided tissue regeneration, crown lengthening and implant dentistry.^3-8

 

The term gingival biotype is used to describe the thickness of the gingiva in the labiolingual dimension.⁹ Gingival biotypes have been previously classified into two or three categories. Ochsenbien and Ross classified gingival biotypes into two types i.e. either scalloped and thin or flat and thick. They also stated that the underlying bone explains the contour of the gingiva above.¹⁰ Siebert and Lindhe categorized the gingiva into ‘‘thick - flat’’ and ‘‘thin – scalloped’’ biotypes. A gingival thickness of ≥ 2 mm was considered as thick tissue biotype and a gingival thickness of <1.5 mm was referred as thin tissue biotype.

 

 

Thick gingival biotype is also called as flat‑thick gingiva, associated to tooth with squared facial form and has distinct cervical convexity, more apically located contact area which is fibrotic and resistant to surgical procedures with a tendency for pocket formation.¹¹ Thick gingival biotype generally depicts broad zone of keratinized tissue with flat gingival contour which indicates thick underlying bony architecture and is more resilient to any inflammation or trauma.¹²

 

Thin gingival tissue is also called as scalloped‑thin gingiva usually associated with tapered crown form, subtle cervical convexity and minute proximal contact areas located near the incisal edge of the tooth.¹¹ Thin gingival margins usually allow visibility of a metal substructure, thus compromising esthetics of the anterior teeth. Thin gingival biotype has thin band of the keratinized tissue and scalloped gingival contour which suggest thin bony architecture and is more sensitive to any inflammation or trauma. Inflammation of the periodontium results in increased pocket formation in thick biotype and gingival recession in thin tissues.¹²

 

Several methodologies have been documented for measurement of the gingival tissue form. This includes visual inspection, ultrasonic devices, Trans gingival probing, and cone beam computerized tomography imaging. The use of trans gingival probing assists as a simple method but requires local anesthesia. The ultrasonic devices although are non‑invasive fail to determine minor differences in gingival tissues.¹³ The use of Cone beam computerized tomography requires technical expertise and becomes expensive with higher radiographic exposure.¹

 

Hence, the simplest method proposed to differentiate thin from thick gingiva is based on the transparency of the periodontal probe through the gingival margin which can help clinician in treatment planning as stated by Kanetal¹⁴ Hence this study was to evaluate the prevalence of gingival biotypes in a Malaysian population and the distribution of the gingival biotypes with varying tooth shapes.

 

MATERIAL AND METHODS:

A total of 150 dental and medical students of Manipal University in the age range of 18-21 years having all maxillary anterior teeth and healthy periodontium were included in the study.

 

Subjects with crown or restorations on maxillary anterior teeth, those on medications with any known effect on the periodontal soft tissue, or presenting with periodontal pockets >3 mm or clinical attachment loss, rotations, cross bite, Mouth breathing habit and trauma from occlusion will be excluded from the study. A duly signed written consent was taken from all the students before periodontal examination. One examiner   recorded all three clinical parameters to avoid bias.

 

Recording of length and width of central incisor, papillary height

 

Papilla height (PH) was   recorded as the distance from the top of the papilla to a line connecting the mid-facial soft tissue margin of the two adjacent teeth. It was assessed to the nearest 0.5 mm using the periodontal probe at the mesial and distal aspect of both central incisors. (figure 1)

 

 

Figure 1. Measurement of papillary height.

 

Gingival thickness (GT) was evaluated and categorized into thick or thin. The thickness was based on the transparency of the periodontal probe through the gingival margin while probing the sulcus at the mid-facial aspect of both central maxillary incisors. If the periodontal probe could be seen through the gingiva, then categorized as thin, if not as thick. (Figure 2)

 

 

Figure 2. Evaluation of gingival thickness.

 

Crown width/crown length ratio (CW/CL) of the right and the left central incisor was measured using digital calipers. The crown length was measured as the distance between the incisal length of the crown and the free gingival margin or cemento enamel junction (CEJ) on the central incisors (figure 3), while the crown width was measured as the border between the middle and the cervical portion. (Figure 3a)

The measurements were tabulated.

 

 

Figure 3. Measurement of crown height.

 

Figure 3a. Measurement of crown width.

 

RESULTS:

For W/L ratio of crown, the mean of 0.88 was taken as cut-off value. That means any ratio falling below 0.88 indicates, longer and narrow CI, and values greater than 0.88 has shorter and broad CI.

 

1.To assess the gingival biotype

Table 1: Distribution of participants according to gender, ethnicity and gingival biotype

RCI - Right Central Incisor; LCI- Left Central Incisor

2.To study the prevalence and correlation of gingival biotypes in relation to gender, ethnicity   and different sizes of maxillary central incisors.

 

Table 2: Mean values of gingival biotype with respect to gender, ethnicity and forms of central incisors

		Gingival Biotype		χ2 value	.sig
Gender		Thick	Thin
	Male	64 (64)	22 (11)	23.52	p < 0.001*
	Female	36 (36)	78 (39)
Ethnicity	Malay	14 (14)	8 (4)	3.17	0.362
	Chinese	61 (61)	54 (27)
	Indian	21 (21)	32 (16)
	Others	4 (4)	6 (3)
Form of Left CI	Long/narrow	53 (53)	46 (23)	0.635	0.419
	Short/Wide	47 (47)	54 (27)
Form of Right CI	Long/narrow	53 (53)	50 (25)	0.12	0.729
	Short/Wide	47 (47)	50 (25)

 

A significant proportion of males had thicker biotypes and females had thinner gingival biotypes. Ethnicity and forms of central incisor had no significant role in gingival biotypes. In addition, Chinese and Malay participants had thicker gingival biotypes when compared to Indians who had thinner gingival biotype. Those with thicker biotypes had long and narrow central incisor and thinner biotypes had shorter and wider left central incisor.

 

3. To determine the prevalence and correlation of gingival biotype in relation to papillary height.

 

Table 3: Mean scores of papillary height in relation to gingival biotypes, gender and ethnicity

 

Papillary height was found to be significantly higher among male participants and those with thick gingival biotypes. Ethnic origin had no significant role, though Malay participants had highest papillary height.

 

DISCUSSION:

Excellent esthetic outcome of a restoration requires healthy periodontium and its compatibility with the surrounding hard and soft tissues. Therefore, during treatment it is essential to recognize gingival biotypes. Gingival biotype helps in better assessment of the treatment outcome in various branches of dentistry and is important in clinical practice.¹⁵ The objective of the present study is to identify the existence of gingival biotypes in a sample of healthy Malaysian students and to correlate their prevalence in accordance with gender, ethnicity and   tooth morphology. The study was carried on 150 students with in the age range of 18-21 years having all maxillary anterior teeth and healthy periodontium.

 

Various method of assessment of gingival biotype includes use of periodontal probe, or visual examination, ultrasonic devices or radiographic methods.^13,1 The transparency of a periodontal probe was used as it is considered atraumatic, rapid and relatively low cost. This method was also found to be an easy, reproducible, reliable and an objective method.⁸

 

The frequency distribution of GT states thicker biotype in males (64%) as compared to females. Females have more number of thin biotype (78%) while 36% have a thick biotype. The results stated are in agreeable to those with De Rock et al¹⁶, Vinayaetal¹⁷, Barakatetal¹⁸ who stated 1/3rd of the sample to be females with a thinner biotype. De rock et al. in their study stated that male participants had thicker gingiva to conceal the periodontal probe when compared to female.  Eghbalietal¹⁹   recorded 1/3rd of female samples with thin scalloped gingival form while 2/3rd of the male samples with broad band of keratinized tissue and thick flat biotype. They also found that the thin biotype in females was associated with long slender teeth while males showed quadratic teeth with thicker biotype. Ethnicity and forms of central incisor had no significant role in gingival biotypes. In addition, Chinese and Malay participants had thicker gingival biotypes when compared to Indians who had thinner gingival biotype.

 

The frequency distribution of prevalence of GT in relation to groups of subjects with varying forms of central maxillary incisors states that short, wider teeth are associated with thin biotype while long slender teeth are associated with thick biotype. Oschbein and Ross ²⁰   were the first to mention the relation of flat thick gingiva with square tooth form and thin gingival biotype with tapered tooth form.  Seo et al²¹ in their study did not find any statistically significant differences between the longer and shorter teeth in relation to gingival biotype.

 

Sanavi et al²² in their review article described that the inter root bone is more in the thinner biotype and can cause more recession. They also stated that the interproximal papilla does not cover the spaces between two teeth in thinner biotype as compared to thick biotype. This could be related to increased amount of recession and also the presence of thin biotype in older age group.  Ranga P etal²³ in their study found that gingival thickness in the anterior region was thicker in the mandibular arch as compared to the maxillary arch. The thickness of mandibular midbuccal and papillary gingiva was thicker than the maxillary gingiva. Chow etal²⁴ evaluated various factors associated with the appearance of gingival papillae and found significant relation with age and the crown form and GT. Warasswapatietal²⁵ explained that racial and genetic factors contributed significantly for the same.

 

 

CONCLUSION:

Within the limitations of the present study, following conclusions were drawn:

1.    The female population consists of thin, scalloped gingival biotype andthicker biotype is more dominant in male population. Chinese and Malay participants had thicker gingival biotypes when compared to Indians who had thinner gingival biotype.

2.    The thicker gingival biotype is associated with long, narrow form of teeth while thinner scalloped biotype is associated with short, wider tooth form. Ethnicity and forms of central incisor had no significant role in gingival biotypes.

3.    Papillary height was found to be significantly higher among male participants and those with thick gingival biotypes. Ethnic origin had no significant role, though Malay participants had highest papillary height.

 

These findings can be utilized for determining the gingival biotype and response of gingiva to dental operative procedures since the gingival tissue’s ability to cover the underlying prosthesis and restoration is necessary for achieving esthetic results, especially in cases of restorative dentistry and in implants, where subgingival restorations are used widely.

 

CONFLICT OF INTEREST: Nil

 

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Accepted on 20.10.2018        © RJPT All right reserved

Research J. Pharm. and Tech 2018; 11(12): 5469-5473.