|Year : 2016 | Volume
| Issue : 2 | Page : 174-177
Comparative evaluation of soft and hard tissue dimensions in the anterior maxilla using radiovisiography and cone beam computed tomography: A pilot study
Savita Mallikarjun, Harsha Mysore Babu, Sreedevi Das, Abhilash Neelakanti, Charu Dawra, Sachin Vaijnathrao Shinde
Department of Periodontology, Dayananda Sagar College of Dental Sciences, Bengaluru, Karnataka, India
|Date of Submission||24-Sep-2014|
|Date of Acceptance||24-Oct-2015|
|Date of Web Publication||11-Apr-2016|
Dr. Abhilash Neelakanti
#1373, 15th Cross, Kumaraswamy Layout, Bengaluru - 560 078, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aims: To assess and compare the thickness of gingiva in the anterior maxilla using radiovisiography (RVG) and cone beam computed tomography (CBCT) and its correlation with the thickness of underlying alveolar bone. Settings and Design: This cross-sectional study included 10 male subjects in the age group of 20–45 years. Materials and Methods: After analyzing the width of keratinized gingiva of the maxillary right central incisor, the radiographic assessment was done using a modified technique for RVG and CBCT, to measure the thickness of both the labial gingiva and labial plate of alveolar bone at 4 predetermined locations along the length of the root in each case. Statistical Analysis Used: Statistical analysis was performed using Student's t-test and Pearson's correlation test, with the help of statistical software (SPSS V13). Results: No statistically significant differences were obtained in the measurement made using RVG and CBCT. The results of the present study also failed to reveal any significant correlation between the width of gingiva and the alveolar bone in the maxillary anterior region. Conclusions: Within the limitations of this study, it can be concluded that both CBCT and RVG can be used as valuable tools in the assessment of the soft and hard tissue dimensions.
Keywords: Alveolar bone thickness, esthetics, gingival thickness, radiographic interpretation
|How to cite this article:|
Mallikarjun S, Babu HM, Das S, Neelakanti A, Dawra C, Shinde SV. Comparative evaluation of soft and hard tissue dimensions in the anterior maxilla using radiovisiography and cone beam computed tomography: A pilot study. J Indian Soc Periodontol 2016;20:174-7
|How to cite this URL:|
Mallikarjun S, Babu HM, Das S, Neelakanti A, Dawra C, Shinde SV. Comparative evaluation of soft and hard tissue dimensions in the anterior maxilla using radiovisiography and cone beam computed tomography: A pilot study. J Indian Soc Periodontol [serial online] 2016 [cited 2019 Dec 16];20:174-7. Available from: http://www.jisponline.com/text.asp?2016/20/2/174/170813
| Introduction|| |
Esthetics is one of the major focuses in dentistry today. It is influenced mainly by gingival morphology and biotype, which in turn is dependent on the architecture of underlying alveolar bone.,,,, Proper treatment planning of an esthetic case, mandates careful evaluation of the thickness of gingiva and underlying alveolar bone. Cone beam computed tomography (CBCT) measurements were confirmed to be an accurate representation of the same. Hence, an attempt is made in this pilot study to assess and compare the thickness of gingiva in the anterior maxilla using radiovisiography (RVG) and CBCT, and to determine its correlation with the thickness of underlying alveolar bone.
| Materials and Methods|| |
Ten male volunteers aged 20–45 years, who reported to the Department of Periodontology, Dayananda Sagar College of Dental Sciences, were included in this study. Verbal and written informed consents were obtained from them. A proper alignment of dentition in the anterior maxilla without the presence of any caries, cervical abrasions or restorations was required for the subjects to be included in the study. Subjects, who underwent crown lengthening procedures and periodontal plastic surgery, in the anterior maxilla and orthodontic treatment, were excluded. Pregnant women and smokers were also excluded from the study. The selected subjects had to undergo both clinical and radiographic examination. The measurements were made for the maxillary right central incisor (index tooth). Clinical examination included the identification of mucogingival junction, and the assessment of the width of keratinized gingiva using UNC-15 (Hu-Friedy) probe. This was done by measuring the distance from the free gingival margin of the index tooth (on the mid-labial aspect) to the mucogingival junction. Radiographic examination included the use of both RVG by paralleling technique and CBCT.
Analysis by RVG included the placement of a lead film on the facial surface of the gingiva [Figure 1]. The lead film was customized for each patient, depending on the width of the keratinized gingiva. Therefore, only its length varied among each patient, whereas a constant width of 0.5 mm was maintained in all cases. After placing the lead film on the index tooth, lateral parallel profile radiographs were taken with the help of a position indicating device, which followed the principles of paralleling technique [Figure 2]. Simultaneously, CBCT scans were obtained from all the patients. To ensure the visibility of the labial gingiva in the anterior region, cheek retractors were used during projection to prevent any contact with the lips [Figure 3].
|Figure 3: Cone beam computed tomography taken with cheek retractors for soft tissue visualization|
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The thickness of gingiva was measured at 4 different levels: At the crest of alveolar bone (G1), 1 mm apical to the crest (G2), at midpoint between the alveolar crest and the mucogingival junction (G3), and at the mucogingival junction (G4) [Figure 4]. Similarly, the alveolar bone thickness was measured at the crest (A1), 1 mm apical to the crest (A2), at the midpoint between alveolar crest and mucogingival junction (A3), and at the mucogingival junction (A4) [Figure 4].
Data so collected was subjected to statistical analysis with the help of statistical software statistical package for soial sciences 13.0 (SPSS Inc., Chicago, USA). Mean values and standard deviations were calculated for all continuous variables. An independent samples t-test was used to test for significant difference between RVG and CBCT measurements of gingival thickness as well as the alveolar bone thickness at different points. Karl Pearson's correlation coefficient (r) was used to find out the relationship between alveolar bone thickness and gingival thickness in each method. A P < 0.05 was considered as the cut-off for determining statistical significance.
| Results|| |
[Table 1] shows the measurements of gingival thickness at various levels using RVG and CBCT. On comparison between the gingival thickness using both methods, no significant difference was observed with respect to the mean values recorded at G1, G2, G3, and G4 points (P > 0.05).
|Table 1: Comparison of gingiva thickness between the two methods using Student's t-test|
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[Table 2] shows the measurements of alveolar bone thickness at various levels using RVG and CBCT. On comparison between the alveolar bone thickness using both methods, no significant difference was observed with respect to the mean values recorded at A1, A2, A3, and A4 points (P > 0.05).
|Table 2: Comparison of alveolar bone thickness between the two methods using Student's t-test|
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[Table 3] shows the correlation between alveolar bone and gingiva thicknesses using RVG. It was observed that the correlation between alveolar bone thickness and gingiva thickness was weak and negative at points A1 and G1(r = −0.136), as well as at points A4 and G4 (r = −0.019). The correlation was found to be negative, but moderate at points A2 and G2 (r = −0.397) and at points A3 and G3, it was found to be positive, but weak (r = 0.276). However, the correlation at any of the points was not statistically significant (P > 0.05).
|Table 3: Correlation between alveolar bone thickness and gingiva thickness in RVG method using Pearson's correlation test|
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[Table 4] shows the correlation between alveolar bone thickness and gingival thickness using CBCT. The results show that the correlation between alveolar bone thickness and gingiva thickness was found to be moderate and negative at points A1 and G1 (r = −0.342) as well as at points A2 and G2 (r = −0.394). The correlation was found to be negative, but weak at points A3 and G3 (r = −0.155) and at points A4 and G4, it was found to be positive, but very weak (r = 0.088). However, the correlation at any of the points was not statistically significant (P > 0.05).
|Table 4: Correlation between alveolar bone thickness and gingiva thickness in CBCT method using Pearson's correlation test|
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| Discussion|| |
Knowledge about the gingival thickness and the alveolar bone thickness has been critical for the long-term success of the various therapeutic approaches in esthetic dentistry. Numerous techniques were proposed to analyze these structures, which include direct technique ,, and indirect methods using radiographic analysis.
Despite being more pertinent in assessing the thickness of the gingiva and alveolar bone, direct measurements using surgical approach and studies on cadavers are not feasible in our routine dental practice. Hence, gingival thickness had been determined traditionally by transgingival probing, probe transparency, ultrasound technique, and also radiographic techniques such as modified technique using RVG  and CBCT. Although hard tissues can be visualized, the soft tissues cannot be clearly distinguished radiographically. Hence, the reliability of these techniques in analyzing the soft tissue dimensions is still dubious.
In this study, there was no statistically significant difference in the thicknesses of gingiva and alveolar bone determined by both RVG and CBCT. This suggests that both these techniques can be used in assessing the soft and hard tissue dimensions.
In this study, a modified radiographic technique proposed by Alpiste-Illueca  was used. Efforts were made to maintain parallelism; however, it was difficult to maintain it all along the length of the plate. This would have led to some errors in the projection and the images were obtained.
Evidence suggests that CBCT imaging has better diagnostic and quantitative accuracy, but the measurements are prone to observational errors. CBCT image, in this study was found to have absence of a reference, which could have also influenced the results. In addition to that the variations in measurements could also be due to the selection of levels, at which the measurements were made.
The thickness of the gingiva is also influenced by the papillary height, crown width and height ratio, and the width of keratinized gingiva. The gingival thickness in this study was found to increase from G1 to G4. The thickness is measured for the attached gingiva only, which has a decreased thickness compared to the free gingiva. Hence, the results of this study were hardly comparable with other studies.
The alveolar bone is mainly a tooth-dependent tissue. In this study, it was noticed that the thickness of the alveolar bone is less toward the crest. This finding is supported by the study by Mol and Balasundaram.
The results obtained in this study are different from those obtained by Olsson et al., who have considered the variations in clinical crown forms. They did not observe any significant different between the study groups with respect to the thickness of free gingiva. Whereas, in our study, there was a positive correlation between the thickness of the alveolar bone and gingiva at the points A3 and G3, while negative correlation was observed at A1 and G1, A2 and G2, and A4 and G4. As such, the findings of our study are also different from Seibert and Lindhe, who concluded that the relationship between gingiva and the underlying bone is mostly unpredictable.
A limitation of this study is that the crown morphologies (tooth forms) and periodontal biotypes  were not taken into consideration while selecting the subjects for this study.
Further research, including a larger sample size with emphasis on tooth forms and periodontal biotypes is warranted, to ensure that the analysis of soft and hard tissue dimensions in the anterior maxilla could become much easier and simpler with RVG, rather than subjecting the individuals to higher radiation doses of CBCT.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]