Digital Intraoral Radiography Research Articles

Comparing the Accuracy of Cone Beam Computed Tomography,Digital Intraoral Radiography and Conventional Intraoral Radiography in the Measurement of Periodontal Bone Defects

Comparing the Accuracy of Cone Beam Computed Tomography,Digital Intraoral Radiography and Conventional Intraoral Radiography in the Measurement of Periodontal Bone Defects

Age estimation using intraoral periapical radiographs.

Context:Changes in the size of dental pulp caused by the apposition of secondary dentin and occlusal wear are morphometric parameters for estimating age.Aim:To estimate the accuracy of age evaluation by Kvaal's method and the effect of occlusal wear on age using digital intraoral periapical radiographs in a subset of the Indian population.Materials and Methods:A total of 300 teeth were radiographically evaluated using intraoral periapical digital radiographs from 50 adult patients. A few modifications were made in the design of the study compared to the original Kvaal's method. The radiographs of three teeth from each jaw were taken and morphometric measurements in ratios were analyzed, which included the pulp length to tooth length (X1), pulp length to root length (X2), pulp width to root widths at three defined levels (X3), and tooth length to root length (X4).Statistical Analysis:The Pearson product-moment correlation coefficient (PCC) between age and the morphological variables showed that among them X1, X2, and X3 were statistically significant but not the tooth root length ratio (X4).Conclusions:The ratios X1, X2, and X3 were good indicators of age and hence a multiple linear regression model for age estimation was derived using these three variables. However, it was found that X4 was not a good indicator of age estimation in said population.

Brazilian young dental practitioners' use and acceptance of digital radiographic examinations.

PurposeThe aim of this study was to investigate the use and acceptance of digital radiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years.Materials and MethodsDental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digital radiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05).ResultsA total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digital radiographic examinations, while in 2015 this number increased significantly to 85.4% (p<.0001), out of which 71.4% preferred it to conventional images. Moreover, 21.4% of respondents reported having used digital radiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digital radiographic examinations.ConclusionThis study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digital radiographic examinations.

The influence of number of line pairs in digital intra-oral radiography on the detection accuracy of horizontal root fractures.

Line pairs are the unit for measurement of resolution and are related to the spatial quality of the system. Thus, the objective of this study was to evaluate the influence of number of line pairs in digital intra-oral radiography on the detection accuracy of horizontal root fractures. Sixty-four extracted single-root human teeth were used. Thirty-two had horizontal root fractures created and were mounted in dry human mandibles. The teeth were radiographed with two digital receptors: the Digora Optime (14.3 lp mm-1) and the Digora Toto (26.3 lp mm-1). Images were viewed under standardized conditions by 3 calibrated examiners using the respective dedicated software (Digora for Windows 2.6(®) and Scanora(®) ). Digora Toto(®) images were also evaluated through the Digora for Windows 2.6(®) software. The results were statistically analyzed based on the area under the ROC curve for each examiner. Pairing Digora Toto(®) with Scanora(®) allowed for greater accuracy in horizontal root fractures diagnosis, while images acquired with that same system seem to lose accuracy when visualized with Digora for Windows 2.6(®) . Pairing Digora Optime(®) with Digora for Windows 2.6(®) resulted in the lowest accuracy for horizontal root fractures diagnosis. The higher number of line pairs and the consequent higher image resolution provided by the Digora Toto(®) system and its dedicated software seem to enhance the accuracy of horizontal root fractures diagnostic imaging.

Radiographic Assessment of Peri-implant Bone Level – A Comparative Study of Digital Intraoral and Digital Panoramic Radiography

Abstract Introduction The objective of this study was to compare two radiographic methods - digital intraoral and digital panoramic radiography in assessing marginal bone level around dental implants. The study also evaluated inter-observer and intra-observer reliability during repeated assessments. Material and Methods Marginal bone around 29 implants in 17 patients was assessed using standardized digital intraoral and digital panoramic radiographs. Two observers evaluated bone level by noting the thread at which marginal bone seemed to be attached at distal and mesial surfaces of the implants. The assessments were repeated after one week. Kappa statistics was used to evaluate agreement between assessments, observers, and radiographical methods. Results The agreement rate between digital intraoral and digital panoramic radiography was fair. Intra-observer agreement was very good, while inter-observer agreement was moderate. Conclusion Digital panoramic radiographs can be used to evaluate marginal bone level in patients with multiple implants and also to supplement intraoral radiographs. However, observer variability should be considered when comparing values from follow up studies for implant maintenance.

Accuracy of digital periapical radiography and cone-beam computed tomography in detecting external root resorption.

PurposeThe purpose of this study was to evaluate and compare the efficacy of cone-beam computed tomography (CBCT) and digital intraoral radiography in diagnosing simulated small external root resorption cavities.Materials and MethodsCavities were drilled in 159 roots using a small spherical bur at different root levels and on all surfaces. The teeth were imaged both with intraoral digital radiography using image plates and with CBCT. Two sets of intraoral images were acquired per tooth: orthogonal (PA) which was the conventional periapical radiograph and mesioangulated (SET). Four readers were asked to rate their confidence level in detecting and locating the lesions. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of each modality in detecting the presence of lesions, the affected surface, and the affected level. Analysis of variation was used to compare the results and kappa analysis was used to evaluate interobserver agreement.ResultsA significant difference in the area under the ROC curves was found among the three modalities (P=0.0002), with CBCT (0.81) having a significantly higher value than PA (0.71) or SET (0.71). PA was slightly more accurate than SET, but the difference was not statistically significant. CBCT was also superior in locating the affected surface and level.ConclusionCBCT has already proven its superiority in detecting multiple dental conditions, and this study shows it to likewise be superior in detecting and locating incipient external root resorption.

Pulp polyp - A periapical lesion: Radiographic observational study

Introduction: Pulp polyp (PP) is a chronic hyperplastic condition resulting in formation of granulation tissue and proliferative mass. The radiographic appearance of PP has innumerable presentations. Diagnosing and treatment planning of periapical lesions, heavily relies on the radiographic changes surrounding the root structures. Objective: To evaluate different radiographic periapical changes in clinically detected PP patients. Materials and Methods: Patients reporting to Department of Oral Medicine and Radiology and who were clinically diagnosed with PP by an oral diagnostician were subjected to radiographic examination. Digital intraoral periapical radiographs of 50 patients with PP were taken. Various periapical changes in the digital radiographs were recorded by a skilled oral radiologist. The data obtained was subjected to statistical analysis using SPSS ver 17.0 and P-value was set at <0.05 as significant. Result: Periapical changes like periodontal space widening (PDLW), loss of lamina dura, periapical abscess, periapical granuloma, hypercementosis, condensing osteitis and root resorption were noted. Periodontal space widening was seen in all patients (100%), loss of lamina dura was noted in 72%, periapical rarefying osteitis in 56%, condensing osteitis in 8%, hypercementosis, periapical granuloma, and root resorption were seen in 4% of PP patients. Majority of PP were asymptomatic (66%). Pulp polyp was commonly seen in mandibular first molar followed by mandibular second molar and maxillary first molar. Statistically significant difference was noticed between periapical changes in PP patients (P value <0.0001). All PP patients showed definite periapical changes suggesting it to be a periapical lesion. Conclusion: Pulp polyp is confined to the pulpal portion of the tooth which, may or may not cause changes in periapical region. The results of the present study showed that majority of the PP patients were associated with definite periapical changes. This observation suggests that clinically detected PP are radiographically associated with definite periapical changes suggesting it to be a periapical lesion.

The efficacy of the reverse contrast mode in digital radiography for the detection of proximal dentinal caries.

PurposeThis study evaluated the diagnostic accuracy of the reverse contrast mode in intraoral digital radiography for the detection of proximal dentinal caries, in comparison with the original digital radiographs.Materials and MethodsEighty extracted premolars with no clinically apparent caries were selected, and digital radiographs of them were taken separately in standard conditions. Four observers examined the original radiographs and the same radiographs in the reverse contrast mode with the goal of identifying proximal dentinal caries. Microscopic sections 5 µm in thickness were prepared from the teeth in the mesiodistal direction. Four slides prepared from each sample used as the diagnostic gold standard. The data were analyzed using SPSS (α=0.05).ResultsOur results showed that the original radiographs in order to identify proximal dentinal caries had the following values for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, respectively: 72.5%, 90%, 87.2%, 76.5%, and 80.9%. For the reverse contrast mode, however, the corresponding values were 63.1%, 89.4%, 87.1%, 73.5%, and 78.8%, respectively. The sensitivity of original digital radiograph for detecting proximal dentinal caries was significantly higher than that of reverse contrast mode (p<0.05). However, no statistically significant differences were found regarding specificity, positive predictive value, negative predictive value, or accuracy (p>0.05).ConclusionThe sensitivity of the original digital radiograph for detecting proximal dentinal caries was significantly higher than that of the reversed contrast images. However, no statistically significant differences were found between these techniques regarding specificity, positive predictive value, negative predictive value, or accuracy.

Detection of root perforations using conventional and digital intraoral radiography, multidetector computed tomography and cone beam computed tomography.

ObjectivesThis study aimed to compare the accuracy of conventional intraoral (CI) radiography, photostimulable phosphor (PSP) radiography, cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) for detection of strip and root perforations in endodontically treated teeth.Materials and MethodsMesial and distal roots of 72 recently extracted molar were endodontically prepared. Perforations were created in 0.2, 0.3, or 0.4 mm diameter around the furcation of 48 roots (strip perforation) and at the external surface of 48 roots (root perforation); 48 roots were not perforated (control group). After root obturation, intraoral radiography, CBCT and MDCT were taken. Discontinuity in the root structure was interpreted as perforation. Two observers examined the images. Data were analyzed using Stata software and Chi-square test.ResultsThe sensitivity and specificity of CI, PSP, CBCT and MDCT in detection of strip perforations were 81.25% and 93.75%, 85.42% and 91.67%, 97.92% and 85.42%, and 72.92% and 87.50%, respectively. For diagnosis of root perforation, the sensitivity and specificity were 87.50% and 93.75%, 89.58% and 91.67%, 97.92% and 85.42%, and 81.25% and 87.50%, respectively. For detection of strip perforation, the difference between CBCT and all other methods including CI, PSP and MDCT was significant (p < 0.05). For detection of root perforation, only the difference between CBCT and MDCT was significant, and for all the other methods no statistically significant difference was observed.ConclusionsIf it is not possible to diagnose the root perforations by periapical radiographs, CBCT is the best radiographic technique while MDCT is not recommended.

A comparative study of the conventional and digital intraoral radiography methods for root canal length measurement

Objective: Measurement of root canal length is one of the most important stages of endodentic treatment, and any error at this stage can lead to the failure. This study aimed to compare conventional and digital intraoral radiography in measurement of root canal length. Material and Methods: In this study, 35 single-canal maxillary teeth were collected. Access cavities were prepared. An endodontic number 10#K- file was introduced into the canal, until the tip was visible at the apical foramen and the actual canal length (gold standard) was determined. After acquisition conventional radiographs using E-Ektaspeed and F-Insight film (Eastman-Kodak Co. Rochester, NY, USA) and digital radiographs using Photostimulable Phosphor Plates(PSP) (Soredex, Helsinki, Finland) and Charge Coupled Devices (CCD)(RVG, Trophy,NY,USA). they were examined separately with a two-week interval by two oral and maxillofacial radiologists. The data were analyzed with ANOVA and Tukey’s tests using SPSS-19 software (SPSS Inc., Chicago, IL, USA). Result: No statistically significant difference was observed between different radiographies, and different observers (P &gt; 0.05). Nevertheless, in comparison with the gold standard, in all cases, the F-speed conventional radiography and the digital CCD radiography showed the highest and the lowest accuracy, respectively. Also, the PSP and the E-speed conventional radiography were in the second and third order of accuracy, respectively. Conclusion: The use of digital radiography does not improve the accuracy of the root canal length measurement,but the digital technique has advantages,such as the reduced patient exposure ,eliminating the time consuming processing stages, and producing fast images.

Comparison the Accuracy of the Cone-Beam Computed Tomography With Digital Direct Intraoral Radiography, in Assessment of Periodontal Osseous Lesions

La Ciotat-France) was taken, and then CBCT (Newtom 3G, Verona. Italy) was carried out. Periodontal flap surgery was done to achieve the gold standard. The distance between cementoenamel junction (CEJ) and the bottom of the vertical pattern of bone loss or the most coronal level of bone in horizontal pattern was measured. These measurements were analyzed by paired t test. The intraclass correlation coefficient (ICC) was used to evaluate the degree of agreement between observers. Results: Accuracy is higher with CBCT in evaluating vertical dimension of periodontal bony defects (0.53 ± 0.59 to 0.56 ± 0.45) (P < 0.001). ICC shows high level of agreement between observers in two image modality. Conclusions: We conclude that CBCT and digital images can be used in periodontal bone assessments; each modality should be chosen based on defect type and patient's specific characteristics.

Imaging of occlusal dentine caries: a comparison among conventional radiographs, digital radiographs, and cone-beam computed tomography images

To compare conventional radiographs, digital radiographs, equalized images of digital radiographs, and cone-beam computed tomography (CBCT) images for in vitro imaging of occlusal dentine caries. A total of 160 extracted human posterior teeth were evaluated in the study. All teeth were free of restorations and proximal caries. The clinical appearances of the occlusal surfaces of the teeth ranged from sound to discolored, with no macroscopic cavitation. Conventional intraoral radiographs, digital intraoral radiographs, and CBCT images of the teeth were taken. The images were evaluated independently by three observers for the presence of occlusal dentine caries. The teeth were then sectioned and computerized images were obtained for the histological sections using a digital camera linked to a stereomicroscope at 10× magnification. The histological images were assessed for the presence or absence of dentinal caries. The sensitivity, specificity, accuracy, and area under the receiver-operating characteristic curve (Az value) were calculated for each diagnostic method. Sensitivity was greatest for CBCT images (mean = 0.63) and lowest for digital radiographs (mean = 0.38). Specificity was greatest for digital radiographs (mean = 0.76) and lowest for CBCT images (mean = 0.64). The mean Az values ranged from 0.56 to 0.60 (P > 0.05). The interobserver and intraobserver agreements were greatest for CBCT images (mean kappa = 0.66 and 0.73, respectively). There were no differences in the accuracy of detection of non-cavitated occlusal dentine caries among the diagnostic modalities used. Cone-beam computed tomography images were more sensitive, while digital radiographs were more specific.

Accuracy of digital radiography and cone beam computed tomography on periapical radiolucency detection in endodontically treated teeth.

ABSTRACTObjectivesThe aim of the present study was to compare the accuracy of intraoral digital periapical radiography and cone beam computed tomography in the detection of periapical radiolucencies in endodontically treated teeth.Material and MethodsRadiographic images (cone beam computed tomography [CBCT] scans and digital periapical radiography [PR] images) from 60 patients, achieved from September 2008 to July 2013, were retrieved from databases of the Department of Oral Diseases, Lithuanian University of Health Sciences. Twenty patients met inclusion criteria and were selected for further evaluation.ResultsIn 20 patients (42.4 [SD 12.1] years, 65% men and 35% women) a total of 35 endodontically treated teeth (1.75 [SD 0.91]; 27 in maxilla and 8 in mandible) were evaluated. Overall, it was observed a statistical significant difference between the number of periapical lesions observed in the CBCT (n = 42) and radiographic (n = 24) examinations (P < 0.05). In molar teeth, CBCT identify a significantly higher amount of periapical lesions than with the radiographic method (P < 0.05). There were significant differences between CBCT and PR in the mean number of lesions identified per tooth (1.2 vs 0.66, P = 0.03), number of teeth with lesions (0.71 vs 0.46, P = 0.03) and number of lesions identified per canal (0.57 vs 0.33, P = 0.005). Considering CBCT as “gold standard” in lesion detection with the sensitivity, specificity and accuracy considering as score 1, then the same parameters of PR were 0.57, 1 and 0.76 respectively.ConclusionsWithin the limitations of the present study, it can be concluded that cone beam computed tomography scans were more accurate compared to digital periapical radiographs for detecting periapical radiolucencies in endodontically treated teeth. The difference was more pronounced in molar teeth.

Low dose x-ray sources and high quantum efficiency sensors: the next challenge in dental digital imaging?

Objective(s). The major challenge encountered to decrease the milliamperes (mA) level in X-ray imaging systems is the quantum noise phenomena. This investigation evaluated dose exposure and image resolution of a low dose X-ray imaging (LDXI) prototype comprising a low mA X-ray source and a novel microlens-based sensor relative to current imaging technologies. Study Design. A LDXI in static (group 1) and dynamic (group 2) modes was compared to medical fluoroscopy (group 3), digital intraoral radiography (group 4), and CBCT scan (group 5) using a dental phantom. Results. The Mann-Whitney test showed no statistical significance (α = 0.01) in dose exposure between groups 1 and 3 and 1 and 4 and timing exposure (seconds) between groups 1 and 5 and 2 and 3. Image resolution test showed group 1 > group 4 > group 2 > group 3 > group 5. Conclusions. The LDXI proved the concept for obtaining a high definition image resolution for static and dynamic radiography at lower or similar dose exposure and smaller pixel size, respectively, when compared to current imaging technologies. Lower mA at the X-ray source and high QE at the detector level principles with microlens could be applied to current imaging technologies to considerably reduce dose exposure without compromising image resolution in the near future.

Image enhancement of digital periapical radiographs according to diagnostic tasks

PurposeThis study was performed to investigate the effect of image enhancement of periapical radiographs according to the diagnostic task.Materials and MethodsEighty digital intraoral radiographs were obtained from patients and classified into four groups according to the diagnostic tasks of dental caries, periodontal diseases, periapical lesions, and endodontic files. All images were enhanced differently by using five processing techniques. Three radiologists blindly compared the subjective image quality of the original images and the processed images using a 5-point scale.ResultsThere were significant differences between the image quality of the processed images and that of the original images (P<0.01) in all the diagnostic task groups. Processing techniques showed significantly different efficacy according to the diagnostic task (P<0.01).ConclusionImage enhancement affects the image quality differently depending on the diagnostic task. And the use of optimal parameters is important for each diagnostic task.

COMPARISON OF DIGITAL RADIOGRAPHY WITH CONVENTIONAL METHOD IN ROOT LENGTH DETERMINATION OF PRIMARY TEETH

ABSTRACT AIM Working length determination in primary teeth endodontics using intra oral digital radiovisiography, and compare it with conventional method for accuracy. METHODOLOGY This in vivo study was conducted on 30 primary teeth which were indicated for pulpectomy in the patients of the age group of 5-11 years All experimental teeth had adequate remaining tooth structure for rubber dam isolation and radiographicaly visible canals. Endodontic treatment was required due to irreversible pulpitis or pulp necrosis. A standardized intraoral periapical radiograph of the tooth was taken using conventional method by paralleling technique. The distance between the source and the tooth, tooth and the films were standardized using X-ray positioning device. RESULT From the results obtained we can conclude that intraoral digital radiography methods of determining the root canal length in primary teeth can be considered reliable and safe in endodontic treatment of children. CONCLUSION The following conclusions were drawn from this present study Intraoral digital radiography also proved to be safest method in determining working length with significant reduction in radiation dosage. Hence this techniques can be safely used as an alternate to conventional radiographic method in determining working length in primary teeth.

In vitro Comparison of Conventional Film and Direct Digital Radiography in Proximal Caries Detection

Introduction: Various systems for intraoral digital radiography have been available as an alternative to film-based radiography. In consideration of several advantages of digital radiography such as less patient absorbed dose, manipulation of im- age quality and elimination of processing, it has been extensively used in different fields of denti- stry in recent years. The purpose of this study was comparison of conventional film and digital radiography in the proximal caries diagnosis. Materials and Methods: In this in vitro study, 60 extracted premolar teeth were selected and mounted in acrylic blocks. The teeth were radio- graphed using F-speed film and a complementary metal oxide semiconductor digital sensor (CMOS). Two observers evaluated interproximal surfaces for detection of presence and extent of caries. True caries depth was determined by his- tological examination. The diagnostic accuracy of each radiographic system were assessed by means of receiver operating characteristic curve (ROC) analysis. Results: There was no significant difference be- tween two imaging modalities. The AZ values in cases without caries and dentinal caries were greater than caries restricted to enamel and Den- tino Enamel Junction (DEJ). The differences among observers also were not statistically sig- nificant. Conclusion: Both imaging modalities were com- parable in the detection of proximal carious le- sions.

An Intraoral Periapical Radiographic Study of Mandibular Nutrient Canals with Conventional and Digital Radiography in Hypertensive Patients: A Comparative Study

Background: Hypertension is one of the most common medical problems seen in our dental profession. Nutrient canals are spaces in bones and are considered to be channels that transmit blood vessels and nerves. They are observed more frequently in the mandibular anterior region as radiolucent lines in intraoral periapical radiographs. The radiographically observable nutrient canals have been shown to have an association with various systemic diseases like hypertension. This can be used as an evidence for the detection of hypertensive patients for better diagnosis and treatment decisions. Aim and objectives: The aim of the present study was to evaluate if any correlation exists between nutrient canals and hypertension. Materials and methods: Two hundred patients with hypertension for 1 to 10 years (groups I and II) and 100 age matched controls (group III) were included in the study. The prevalence of nutrient canals in all the groups and with reference to age and gender was observed along with the comparison between intraoral conventional and digital radiography.

Intraoral Digital Radiography for Adult Age Estimation: A Reliable Technique

Aims and objectives: This study aimed at estimating the age of an individual from mandibular premolars using the pulp to tooth area ratio (AR) measured from the digital intraoral radiographic images or radiovisuographic images (RVGs). Materials and methods: The study comprised of 120 patients divided into two subsets of 30 test subjects and 90 study subjects. The RVG images of mandibular premolars were acquired and the pulp to tooth area ratio was measured using the software Jenoptic ProgRess Version 2.7. Pearson’s correlation test and regression analysis was employed. Intraobserver variation was evaluated with paired t-test. Results: The AR was a significant (p-value <0.001) predictor of age with a mean absolute error (MAE) of 5.38 years using the formula, Age = 89.778-379.020 (AR). This equation when applied on the test subset revealed no statistically significant difference (p = 0. 256) between estimated and chronological ages with no gender differences. The age estimated from the RVG images were more accurate in 36 to 50 year patients. Conclusion: Considering that the acceptable error limits for forensic age estimation is being less than ±10 years, this method of age estimation provides a fairly accurate and reliable noninvasive method.

Alveolar bone density changes around miniscrews: A prospective clinical study

Our objective was to assess the effects of miniscrews on interproximal alveolar bone density and adjacent gingival tissue health. Forty-four titanium miniscrews were inserted between maxillary second premolars and first molars on both sides of the dentition in 22 consecutive patients (15 female, 7 male; ages, 14-24 years). A control area (between the maxillary first and second premolars) was also assessed. Both miniscrew (study) and control areas were monitored clinically and radiographically at different time points: before insertion of the miniscrews and at 1 month, 3 months, and 6 months after insertion. Software associated with a digital intraoral radiography machine was used to assess changes in alveolar bone density. Clinical gingival parameters of the study and control areas were also recorded. A repeated-measures analysis of variance and the Bonferroni post-hoc pairwise comparison tests were used to assess the changes at the different time points. Thirty-nine miniscrews were successful for the study duration. Male subjects had significantly (P <0.001) higher alveolar bone density than did the females at baseline. Alveolar bone density around the miniscrews increased significantly (P <0.001) between 3 and 6 months after insertion upon loading. Alveolar bone density of the control area did not change significantly during the experiment (P >0.05). The width of keratinized gingiva increased significantly (P <0.001) in the study and control areas after insertion of miniscrews and remained with no significant change throughout the study. Miniscrews increased the alveolar bone density significantly after 3 months of insertion and were not associated with detrimental effects on the adjacent gingival tissues.