INTRODUCTION:

The gingival morphology of the maxillary anterior region plays an important role in determining the final aesthetic outcome as it is associated with the outcomes of periodontal therapy, root coverage procedures and implant esthetics.¹Biotype defined as part of body having the same genotype. The identification of the gingival biotype may be important in clinical practice since difference in gingival and osseous architecture have been shown to exhibit a significant impact on the outcome of restorative therapy.²The stability of the osseous crest and soft tissue is directly proportional to the thickness of the bone and gingival tissue. The term gingival or periodontal phenotype has recently been coined by Seibert and Lindhe³to address a common clinical observation of great variation in thickness and width of facial keratinized tissue and they categorized the gingiva into thick and thin. The thick gingiva is characterized as bulky, slightly scalloped gingival margins with short wide teeth and the thin gingiva is characterized by highly scalloped gingival margins with slender teeth.^2,3Claffey and Shanley⁴ defined that the gingival tissue biotype is thin if gingival thickness is <1.5 mm and thick if its thickness is ≥ 2 mm. It is a widely accepted clinical impression that a thin, highly-scalloped gingiva tends to recede from source of irritation (artificial crown margin or microbial irritants) and gingival recession often occurs following traumatic or surgical injury.

Received on 23.04.2015 Modified on 05.05.2015

Research J. Pharm. and Tech. 8(5): May, 2015; Page 565-570

DOI: 10.5958/0974-360X.2015.00094.3

In literature, the thickness of masticatory mucosa is evaluated by both non-invasive and invasive methods. Non invasive methods are spiral computed tomography and transducer probe (ultrasonic probe). These methods have certain limitation like only low – resolution image is produced depending on the anatomic features and also they deliver high radiation dose to the patient. Another limitation of non - invasive procedure is that they are time consuming and expensive.⁵ Invasive method of assessing masticatory mucosa includes conventional histology on cadaver jaws, histological section or cephalometric radiographs, direct bone sounding using a periodontal probe, an endodontic reamer, or an injection needle after adequate local anesthesia.⁶ However such measurements can be affected by precision of the probe, the angulation of the probe and dimension of tissue during probing.⁷

Thus the present study was carried out with an aim to evaluate the thickness of facial gingiva in anterior teeth and palatal mucosa in posterior teeth by trans-gingival probing and determine the relation of thickness of gingiva with age, sex, crown width/crown length ratio and dental arch

MATERIALS AND METHODS:

Subjects selection

The review committee constituted by the Institute of dental studies and technologies approved the protocol for human subjects.Statistically significant number of systemically healthy volunteers will be selected from Department of Periodontics, Institute of Dental Studies and Technology, Modinagar, Ghaziabad, U.P.

Inclusion criteria

1. Healthy periodontal tissues with no loss of attachment. 2. Presence of all anterior teeth in both maxillary and mandibular arch.

Exclusion criteria

1. Pregnancy and lactation.

2. Gingival recession in the anterior teeth.

3. Systemic disease.

4. Extensive restorations.

5. Use of any medication possibly affecting the periodontal tissues such as cyclosporin A, calcium channel blockers and phenytoin.

6. History of any palatal surgery.

7. Wearing of any removable device in the upper jaw, such as removable partial dentures or orthodontics plate retainers.

8. Presence of any fixed partial denture in upper jaw. 9. Smoking habits. The selected subject will be explained about the study plan and will sign an informed consent regarding the study.

Pre hygienic phase In the first visit, oral hygiene instruction will be given followed by scaling and polishing.

Clinical Parameters

Full mouth Plaque index (PI) Silness and Loe 1964 and Gingival Bleeding Index (GBI) Ainamo and Bay 1975 will be recorded. Probing depth (PD) will be measured at all 4 sites (ie. Mesio labial, Mid labial, Disto labial, Mid lingual) of both maxillary and mandibular anterior teeth with UNC-15 probe.Crown width/crown length ratio (CW/CL) of the central incisor will be determined according to Olsson and Lindhe. The crown length will be measured between the incisal edge of the crown and the free gingival margin. The length of crown will be divided into three equal portion of equal height. Crown width i.e. the distance between the approximal tooth surfaces, will be recorded at the border between the middle and cervical portion. Gingival width (GW) will be measured midfacially in both maxillary and mandibular anterior teeth with a periodontal probe (UNC-15, Hu-Freidy) as the distance from the free gingival margin to the mucogingival junction.

Masticatory mucosa thickness

Assessment in the attached gingiva

The gingival thickness will be assessed midbuccally in the attached gingiva, half way between the mucogingival junction and the free gingival groove and at the base of the inter dental papilla.The gingival thickness will be assessed by anaesthetizing the facial gingiva with xylonar spray (15mg) and if required, infiltration will be conducted using 2% lignocaine HCL with 1:80,000 adrenalin injection; Using UNC-15 probe, the gingival thickness will be assessed 20 min. after injection.(fig. 1)

Figure:1

Assessment in the hard palate

The masticatory mucosal thickness will be measured in the hard palate by "bone sounding" with a UNC-15 periodontal probe. Different lines parallel to the gingival margin between the canine and second molar will be defined to determine 18 standard measurement points in the hard palate. 3 different lines (a, b and c) running parallel to the gingival margin will be established starting at the mid-palatal aspect of the canine and ending over the palatal root of the second molar. The distances from the gingival margin to lines a, b and c will be 3 mm, 8 mm and 12 mm, respectively. Therefore, the gingival width between line a and c will be 9 mm. Six points will be defined on each of the lines, constituting 6 positions, each located at the level of a tooth. Position Ca will be determined at the mid-palatal aspect of the canine, position P1 at the mid-palatal aspect of the first premolar, position P2 at the mid-palatal aspect of the second premolar, position M1 over the palatal root of the first molar, position Mi at the interproximal aspect between the first and second molar, and position M2 over the palatal root of the second molar.(fig. 2, 3, 4, 5)

RESULTS:

The present study consisted of forty systemically healthy subjects (20 males, 20 females) in the age range of 16–38 years selected from the Out Patient Department of Periodontics, Institute of Dental Studies and Technologies, Modinagar on the basis of the screening criteria. Demographic details along with crown width and crown length ratio, thickness of gingiva in maxillary and mandibular anterior teeth (interdental and midbuccal areas – total of 24 points) and posterior palatal mucosa (total of 18 points) were recorded in all the patients by transgingival probing after giving adequate anaesthesia with the help of UNC -15 periodontal probe. Crown width / crown length ratio was calculated for the entire study population through the study casts in the maxillary and mandibular anterior region. All the recordings were recorded in tabulated form and The data collected was statistically analysed by using the software SPSS (Statistical Package For Social Sciences) version 16.0. with application of two test Unpaired t-test and Mann–Whitney U test.

In anterior maxillary mandibular region

1. The younger age group had significantly thicker gingiva than that of the older age group. (Table.I)

2. The gingiva was found to be thinner in females than males. (Table.II)

3. The gingiva was found to be thicker in mandibular arch than the maxillary arch. (Table.I)

4. The crown width/crown length ratio was found to be more in maxillery arch than mandibular arch. (Table.VI)

In posterior palatal mucosa

1. In the hard palate, soft tissue thickness progressively increased in sites further from the gingival margin. (Table.IV,V)

2. The palatal mucosal thickness adjacent to the palatal root of the first molar was significantly thinner compared to other positions in the hard palate, presenting an anatomical barrier in graft harvesting(Table.IV,V)

3. Younger age group has thiner mucosa than older age group ( Table.IV)

4. Male had the thicker posterior mucosa than females (Table.V)

Table I - Dental arch wise comparison of thickness of gingiva in anterior region

TYPE OF ARCH	INTERDENTAL PAPILLA (MEAN±S.D.)	MIDBUCCAL (MEAN±S.D.)	MIDBUCCAL V/S INTERDENTAL (p value)
Maxilla	1.30±0.30	1.10±0.15	0.0004*
Mandible	1.44±0.44	1.16±0.21	0.0001*
Maxilla v/s mandible (p value)	0.0095*	0.6849	---

Table II - Age wise distribution of thickness of gingiva in anterior region

AGE GROUP	INTERDENTAL PAPILLA (MEAN±S.D.)			MIDBUCCAL (MEAN±S.D.)		Mandible (MEAN±S.D.) (p value)
AGE GROUP	Maxilla (MEAN±S.D.)	Mandible (MEAN±S.D.)	(p value)	Maxilla (MEAN±S.D.)	Mandible (MEAN±S.D.)	Mandible (MEAN±S.D.) (p value)
16-24 YRS	1.49±0.30	1.59±0.47	0.1268	1.15±0.20	1.22±0.29	0.3868
25-38 YRS	1.15±0.24	1.29±0.30	0.3870	1.02±0.08	1.04±0.11	0.6396
INTER AGE GROUP COMPARISON	0.0018*	0.0056*	-	0.0029*	0.0034*	-

Table III - gender wise distribution of thickness of gingiva in anterior region

GENDER GROUP	INTERDENTAL PAPILLA (MEAN±S.D.)			MID BUCCAL (MEAN±S.D.)
GENDER GROUP	Male (MEAN±S.D.)	Female (MEAN±S.D.)	(p value)	Male (MEAN±S.D.)	Female (MEAN±S.D.)	(p value)
MAXILLA	1.55±0.20	1.06±0.14	0.000*	1.23±0.16	1.00±0.00	0.000*
MANDIBLE	1.80 ±0.31	1.08±0.15	0.000*	1.27±0.23	1.02±0.07	0.000*
INTER GROUP COMPARISON	0.0047	0.007	-	0.5979	0.9834	-

Table IV - Age wise intergroup comparison of thickness of posterior palatal mucosa in different notified areas

TYPES OF TOOTH	Aa1 vs Aa2 (p value)	Ab1 vs Ab2 (p value)	Ac1 vs Ac2 (p value)
Ca	0.122	0.162	0.506
P1	0.161	0.805	0.177
P2	0.212	0.083	0.004*
M1	0.403	0.188	0.319
Mi	0.621	0.809	0.808
M2	0.169	0.917	0.002*

Aa1, Ab1, Ac1 = Average of mean gingival thickness of posterior palatal mucosa at 3,8,12 mm from gingival margin in younger age group respectively. Aa2 Ab2 Ac2= Average of mean gingival thickness of posterior palatal mucosa at 3,8,12 mm from gingival margin in older age group respectively.

Table no. V - Gender wise intergroup comparison of thickness of palatal mucosa in different areas

TYPES OF TOOTH	Ga1 vs Ga2	Gb1 vs Gb2	Gc1 vs Gc2
Ca	0.16	0.56	1.00
P1	0.13	0.33	1.00
P2	0.36	1.00	0.27
M1	0.56	0.41	0.47
Mi	0.26	0.08	0.56
M2	0.27	0.10	0.79

Ga1 Gb1 Gc1= Average of mean gingival thickness of posterior palatal mucosa at 3,8,12 mm from gingival margin in male patients

Ga2 Gb2 Gc2= Average of mean gingival thickness of posterior palatal mucosa at 3 mm from gingival margin in female patients

TABLE VI- Dental arch wise comparsion of crown width/crown length ratio of teeth in anterior region

ARCH LOCATION	CW/CL RATIO (MEAN±S.D.)	p VALUE
MAXILLA	0.68±0.10	0.000*
MANDIBLE	0.62±0.94	0.000*

DISCUSSION:

Gingival morphology of the gingiva specially in the maxillary anterior region plays an important role in determining the final esthetic outcome after any periodontal treatment.¹Thick gingival tissue is probably the image most associated with periodontal health. Surgical evaluation often reveals thin labial bone with the possible presence of fenestration and dehiscence.⁸ Difference in the biotype has often been associated with the difference in clinical outcome, with the outcome being unpredictable in the thin biotype. Previous studies have-confirmed that shallower pockets may be expected in patients with a thin - scalloped biotype and that deeper pockets coincide with thick and flat biotype.^3,9Various studies have also found that gingival thickness is related with patients age, gender and dental arch location was a significant predictor of the clinical outcome of certain procedures in periodontal surgery and esthetic outcomes.^{10,1,4,7,11-13}

Hence, this cross sectional study was conducted in the Department of Periodontics, Institute of Dental Studies and Technologies, Modinagar, U.P. with the aim to
evaluate the thickness of facial anterior gingiva and posterior palatal mucosa by transgingival probing and to determine the relation of gingival thickness / biotype with age, gender, dental arch location and crown width/crown length ratio. Fourty subjects consisting of twenty males and twenty females in the age range of 16 - 38 years were included in the study. In the present study, the study population was divided into two groups based on the age criteria, (a) Younger age group (16-24 years) and (b) Older age group (25-38 years). This was in accordance to the study groups in the study done by Vandana KL and Savita B.¹⁰

In the present study, 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 but the statistically significant difference was found only in interdental papillary region. Similar results were seen in the study was conducted by Vandana KL and Savita B¹⁰and our results were in contrast to the results of Muller et al¹⁴ who found the gingiva to be thicker in the maxilla than in the mandible, with the thinnest facial gingiva found at maxillary canines as well as mandibular first premolars. In the present study, gingiva in the anterior region was thicker in the younger age group than the older age group which was similar to study conducted by Vandana KL and Savita B.¹⁰ Gingiva in younger group might be thicker than the older group because of changes in the oral epithelium caused by age, related to thinning of the epithelium and diminished keratinization (Van der Velden).¹⁵

In our study, anterior gingiva was seen to be thinner in females than male which were similar to the findings of Vandana KL and Savita B,¹⁰De Rouck T et al²_, Muller et al,¹⁴ and Anand V et al.¹⁶ These results may be due to estrogen hormone in females which may be responsible for physiological changes at specific phases of life starting in puberty^1,4,7,15Many other factors may have contributed to these conflicting results, such as differences in the ethnicity of the subjects, reference structures, and measurement techniques, all indicating the need of future investigations with larger sample sizes.^15,16

In our study, the crown width / crown length ratio was more in maxillary arch than mandibular arch and it was also found that crown width / crown length ratio was significantly higher in thick biotype (14males and 1 female) as compared to thin biotype (19 females and 6 males).Similar studies were conducted by De Rouck T et al²and Anand V et al ¹⁶in which they concluded that thick gingival cluster had more crown width /crown length ratio and also found that females had thin gingiva than males and exhibited slenderic tooth form in thin biotype and quadratic tooth form in thick biotype respectively. In the present study, the mean thickness of the posterior palatal mucosa ranged between (over the palatal root of the first molar 3mm away from gingival margin) to (mid palatal aspect of the second premolar 12 mm away from gingival margin). Mucosa in the hard palate 12 mm away from the gingival margin revealed significantly thicker values than in distances of 3 mm or 8 mm. Hence, the palatal root of the first molar represents an anatomic barrier in graft harvesting in the hard palate but it is not advisable to harvest soft tissue grafts beyond this structure to avoid an increasing risk for accidental damage to the greater palatine artery or its branches and thicker palatal grafts may be harvested if obtained several millimetres away from the gingival margin of the teeth. Thus the area of the palate from the distal line angle of the canine to the mesial line angle of the palatal root of the first molar provides sufficient donor tissue for grafting procedures and also reduces the risk of violating the associated neurovascular structures.^15,17-21

In the present study, the younger age group had significantly thinner mucosa than the older age group in relation to posterior palatal mucosa. Younger age group had significantly thinner posterior palatal mucosa because the thickness of ortho-keratinized epithelial layer of the hard palate mucosa increases with age, resulting in the thicker palatal mucosa in the older subjects. In addition, the hard palate possesses a sub mucosal layer, which contains various amounts of adipose tissue and small mucous glands. There are other factors that influence the mucosal thickness such as racial, genetic factors and body weight.^16,19-21

In the present study, posterior palatal mucosal thickness was found to be more in males as compared to females; however, it was not statistically significant. The results were in accordance to the study done by Eger T et al,¹⁷ Kuriakose A,⁵Studer et al,¹⁸ Waraswapati N et al,²²Mullar HP,¹⁴and in contrast with the study done by Schacher B et al²³ who stated that females had thicker mucosa than males which basically depends on body mass. In general, the thickness of gingiva in both the anterior region of maxillary and mandibular arches and posterior palatal mucosa shows a varied degree of variation and the difference in the mean thickness might be due to age, gender, dental arch location, crown width/ crown length ratio, ethnicity, varying measurement methods and the placement of measurement.

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10. Vandana KL, Savitha B. Thickness of gingiva in association with age, gender and dental arch location. J Clin Periodontol 2005;32:828-830.

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18. Studer SP, Allen EP, Rees TC, Kouba A. The thickness of mucosa in the human hard palate and tuberosity as potential donor sites for ridge augmentation procedures. J Periodontol 1997;68:145–151

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20. Olsson M, Lindhe J, Marinello CP. On the relationship between crown form and clinical features of the gingiva in adolescents. J Clin Periodontol 1993;20(8):570-577.

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22. Waraswapati N, Pitiphat W, Chanderapho N, Rattanayatikul C, Ranimdux N. Thickness of mastricatory mucosa associated with age. J Periodontol 2001; 72:1407-1412.

23. Schacher B, Burklin T, Horodko M, Ratze P, Kruger PR, Eicholz P. Direct thickness measurement of the hard palate. Quintenssence Int 2010; 41:149-156.


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