Comparison of conventional imaging techniques and CBCT for periodontal evaluation: A systematic review

Nonionizing diagnostic imaging modalities for visualizing health and pathology of periodontal and peri-implant tissues

Radiographic examination has been an essential part of the diagnostic workflow in periodontology and implant dentistry. However, radiographic examination unavoidably involves ionizing radiation and its associated risks. Clinicians and researchers have invested considerable efforts in assessing the feasibility and capability of utilizing nonionizing imaging modalities to replace traditional radiographic imaging. Two such modalities have been extensively evaluated in clinical settings, namely, ultrasonography (USG) and magnetic resonance imaging (MRI). Another modality, optical coherence tomography (OCT), has been under investigation more recently. This review aims to provide an overview of the literature and summarize the usage of USG, MRI, and OCT in evaluating health and pathology of periodontal and peri-implant tissues. Clinical studies have shown that USG could accurately measure gingival height and crestal bone level, and classify furcation involvement. Due to physical constraints, USG may be more applicable to the buccal surfaces of the dentition even with an intra-oral probe. Clinical studies have also shown that MRI could visualize the degree of soft-tissue inflammation and osseous edema, the extent of bone loss at furcation involvement sites, and periodontal bone level. However, there was a lack of clinical studies on the evaluation of peri-implant tissues by MRI. Moreover, an MRI machine is very expensive, occupies much space, and requires more time than cone-beam computed tomography (CBCT) or intraoral radiographs to complete a scan. The feasibility of OCT to evaluate periodontal and peri-implant tissues remains to be elucidated, as there are only preclinical studies at the moment. A major shortcoming of OCT is that it may not reach the bottom of the periodontal pocket, particularly for inflammatory conditions, due to the absorption of near-infrared light by hemoglobin. Until future technological breakthroughs finally overcome the limitations of USG, MRI and OCT, the practical imaging modalities for routine diagnostics of periodontal and peri-implant tissues remain to be plain radiographs and CBCTs.

Convolutional-neural-network-based radiographs evaluation assisting in early diagnosis of the periodontal bone loss via periapical radiograph

Background/Purpose

The preciseness of detecting periodontal bone loss is examiners dependent, and this leads to low reliability. The need for automated assistance systems on dental radiographic images has been increased. To the best of our knowledge, no studies have quantitatively and automatically staged periodontitis using dental periapical radiographs. The purpose of this study was to evaluate periodontal bone loss and periodontitis stage on dental periapical radiographs using deep convolutional neural networks (CNNs).

Materials and methods

336 periapical radiographic images (teeth: 390) between January 2017 and December 2019 were collected and de-identified. All periapical radiographic image datasets were divided into training dataset (n = 82, teeth: 123) and test dataset (n = 336, teeth: 390). For creating an optimal deep CNN algorithm model, the training datasets were directly used for the segmentation and individual tooth detection. To evaluate the diagnostic power, we calculated the degree of alveolar bone loss deviation between our proposed method and ground truth, the Pearson correlation coefficients (PCC), and the diagnostic accuracy of the proposed method in the test datasets.

Results

The periodontal bone loss degree deviation between our proposed method and the ground truth drawn by the three periodontists was 6.5 %. In addition, the overall PCC value of our proposed system and the periodontists' diagnoses was 0.828 (P < 0.01). The total diagnostic accuracy of our proposed method was 72.8 %. The diagnostic accuracy was highest for stage III (97.0 %).

Conclusion

This tool helps with diagnosis and prevents omission, and this may be especially helpful for inexperienced younger doctors and doctors in underdeveloped countries. It could also dramatically reduce the workload of clinicians and timely access to periodontist care for people requiring advanced periodontal treatment.

Influence of the presence of dental implants on the accuracy and difficulty level of diagnosis of furcation involvement in molars: An in vitro CBCT study

OBJECTIVE

The aim of this study was to investigate the possible interference of image artifacts (IA) generated by dental implants in the evaluation of furcation involvement (FI) in molars.

METHODS

Tomographic scans of first molars (1M) were performed in dry skulls in the absence and presence of titanium (TI) and zirconia (ZI) dental implants. FI grades were simulated in the alveoli of the 1Ms. Diagnostic accuracy of FI and level of difficulty were verified. Chi-squared test and logistic regression analysis were used.

RESULTS

There was no difference in the diagnostic accuracy of FI between the arches (p = .117). The highest diagnostic accuracy value for the implant variable was found in the absence of implants (88.3%) and the lowest in the presence of two ZI implants (66.7%). The highest diagnostic accuracy value for FI was observed in grade 0 (G0). There was no significant difference between the arches regarding the evaluators' perception of difficulty (p > .05). Assessments were considered difficult in 12.7% of the TI implants and in 29% of the ZI implants. Regarding the number of dental implants, assessments were considered difficult in 24.4% cases including one implant and 17.4% cases including two implants. The logistic regression model showed a significant p-value only for one and two ZI implants (p = .0061 and p = .0096, respectively).

CONCLUSION

The presence of dental implants in the region adjacent to the area of investigation of FI decreased the diagnostic accuracy while increasing the perception of difficulty by the examiners, especially in cases with ZI implants.

Comparative Assessment of Reliability and Accuracy of Cone-Beam Computed Tomography (CBCT) Over Direct Surgical Measurement for Periodontal Bone Loss: A Prospective, Cross-Sectional Study

INTRODUCTION

Assessing bone condition holds significant value in the diagnosis, treatment planning, and prognosing the periodontal disease; its importance is undeniable. The main aim of the present study was to evaluate the accuracy of alveolar bone measurements due to periodontal disease using cone-beam computed tomography (CBCT), by comparing with surgical measurements, considered as the gold standard.

MATERIALS AND METHODS

A prospective cross-sectional study included a sample of 40 individuals diagnosed with chronic periodontitis who required periodontal surgery. A total of 202 sites were assessed for vertical and horizontal bone loss in the anterior (76 sites) and posterior (126 sites) teeth. Bone loss was measured using CBCT and a UNC 15 periodontal probe during the surgical intervention, and then compared. The statistical analysis involved employing a Student's t-test to compare measurements. Unpaired t-tests and correlation analyses were conducted using Pearson's correlation coefficient test. To establish statistical significance, a threshold of p<0.05 was considered appropriate.

RESULTS

The statistical analysis carried out on the mean values of CBCT and direct surgical measurements for vertical bone loss demonstrated a significant difference (p<0.01). However, the values obtained for horizontal bone loss did not display statistical significance. A strong correlation of 0.94-0.99 existed between surgical and CBCT measurements. A statistically significant distinction was observed between the two methods in measuring bone loss at the distal and palatal sites of the anterior teeth.

CONCLUSION

Both CBCT and direct surgical measurement exhibit comparable accuracy potential in assessing alveolar bone loss. CBCT provides an accessibility advantage by enhancing visual access to challenging sites during surgical interventions, including palatal and distal areas of the teeth.

Clinical success of guided tissue regeneration for treating vertical bone and furcation defects in dogs

This study evaluated the clinical success rate of guided tissue regeneration (GTR) for treating advanced periodontal disease in a large canine cohort. A total of 112 GTR procedures performed from 2003-2021 were retrospectively evaluated, including pre- and post-treatment (3-12 months) periodontal probing depths of 104 treated teeth, dental radiographs of 73 treated teeth, and both diagnostic modalities in 64 treated teeth. Probing depth, radiographically apparent bone height, bone graft material, barrier membrane material, and tooth extraction adjacent to the GTR site were investigated as factors affecting success. Vertical bone defects were evaluated separately from furcation defects. GTR was clinically successful, defined as objective improvement in probing depth, objective decrease in radiographic vertical bone defect, and subjective radiographic gain in bone height in 90.3% of vertical bone defects. Success was significantly associated with the magnitude of initial probing depth and the type of barrier membrane used. GTR was clinically successful, defined as objective improvement in furcation probing and subjective radiographic improvement of the bone in the furcation in 22.2% of furcation defects. When F3 lesions were excluded, GTR was successful in 64.3% of furcation defects. GTR is an appropriate treatment to maintain teeth in the oral cavity of dogs with proper client counseling and patient selection, but it is most likely to be successful in vertical defects.

Correlation of Serum Vitamin D with Crestal Bone Level in Dental Implant Patients Using CBCT: A Clinical Retrospective Study

AIM

The purpose of this study is to correlate the role of serum vitamin D levels associated with crestal bone in dental implant patients using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

This retrospective study enrolled patients among whom implants were placed after a detailed planning using CBCT and the delayed loading protocol was followed. After 3 months and 6 months of loading, CBCT evaluations were carried out, serum vitamin D levels were also tested at the end of 6 months of loading. A total of 30 patients were recruited with 15 patients in each group based on normal and deficient levels of vitamin D to correlate with crestal bone levels using CBCT.

RESULTS

Clinically acceptable crestal bone loss (CBL) was visible with all the implants at different time intervals. Statistical analysis was done for intergroup and intragroup comparisons which showed significant p-value (< 0.05) for CBL at the time of loading, at 3 months, and at 6 months follow-up for both normal and deficient serum values. In the deficient group, the mean value at baseline was 9.69 mm ± 1.10 and the CBL at 6 months follow-up was 8.80 mm ± 1.10 whereas for the normal group at baseline, the mean was 9.08 mm ± 1.21 and at 6 months follow-up was 8.12 mm ± 1.25 which showed meaningful difference.

CONCLUSION

There is a positive correlation seen between CBL on CBCT and vitamin D serum levels. The success of the implant is significantly affected by vitamin D as it regulates the bone physiology and has systemic effects on accelerating bone formation around titanium implants.

CLINICAL SIGNIFICANCE

Vitamin D is essential in maintaining the balance of bone minerals and assists to preserve the crestal bone level making the implant treatment more predictable and successful.

Automatic exposure compensation of digital radiographic technologies does not affect alveolar bone-level measurement

OBJECTIVE

To evaluate whether the automatic exposure compensation in the presence of high-density materials can affect the measurement of alveolar bone level.

METHODS

Thirty regions of seven dry skulls and six mandibles were radiographed with and without a high-density material, using two digital radiographic technologies: photostimulable phosphor plate (PSP, Digora Optime) and sensor (CMOS, Digora Toto), totaling 120 images. The distances from the cement-enamel junction to the alveolar bone crest were measured using cone-beam computed tomography (CBCT) images to represent the reference standard. The same measurements of alveolar bone level and the average of the pixel values of the image were evaluated on the radiographs. Paired t test compared the average pixel values and alveolar bone-level measurements between images with and without high-density material. One-way analysis of variance compared the difference between radiographic and CBCT measurements (α = 0.05).

RESULTS

The high-density material reduced the pixel values in PSP (p = 0.002) and CMOS (p < 0.001) technologies, demonstrating the AEC functioning in both technologies. There was no difference in bone-level measurements between the images without and with the high-density material for both technologies (p ≥ 0.091), or between the tomographic and radiographic measurements (p ≥ 0.319).

CONCLUSION

In the presence of high-density material, the automatic exposure compensation reduces the average pixel values of the images (i.e., images get darker), but does not influence the radiographic measurements of alveolar bone level.

Is the efficacy of cone beam computed tomography in the diagnosis of tooth ankylosis influenced by dose reduction protocols?

OBJECTIVE

To evaluate the diagnostic efficacy of cone beam computed tomography (CBCT) examinations acquired with varying dose protocols in the diagnosis of simulated tooth ankylosis (TA).

STUDY DESIGN

Tooth ankylosis was simulated in 15 of 30 teeth, and CBCT examinations were acquired at 3 mA levels (8, 6.3, and 5) and 3 voxel sizes (0.08, 0.125, and 0.2 mm). Four radiologists independently assessed the presence of TA using a 5-point scale. Sensitivity, specificity, and area under the curve (AUC) obtained through receiver operating characteristic analysis were compared among mA levels and voxel sizes using two-way analysis of variance (α = 0.05). Intra- and interexaminer reliability levels were assessed with the weighted kappa examination.

RESULTS

Sensitivity was low (0.32-0.49), and specificity was reasonably high (0.71-0.83). Mean values of AUC were low, ranging between 0.54 and 0.67, which reveals poor overall discrimination between health and disease. The detection of TA was not significantly influenced by mA level or voxel size (P > .05). Intra- and interexaminer agreements ranged from slight to moderate (0.160-0.535) and from fair to substantial (0.236-0.697), respectively.

CONCLUSIONS

Despite the limited efficacy of CBCT for TA detection, when indicated as a complementary examination, mA reduction should be considered for dose optimization purposes.

Radiographic Examination before Dental Extraction from Dentists' Perspective

Background

It is generally agreed that radiographic examination is important before dental extraction. It provides information about the roots and the surrounding tissues. In terms of practice, it does not seem to be a universally implemented protocol regarding the use of dental radiology before dental extraction. Besides, the type of radiographic technique is not specified. Some references prefer periapical dental radiographs. Others prefer orthopantomography), or even cone beam computed tomography Delpachitra et al. (2021) [1]. In terms of the dental practice, it is not clear whether there is a universally adopted protocol regarding the use of dental radiographs before dental extraction. Aim of the study. To assess dental professionals' perspective toward radiographic examination before conventional dental extraction.

Materials and Methods

A Google form questionnaire was circulated to different dental professionals using mainly ResearchGate, in addition to different social media platforms.

Results

One hundred and forty-five dentists participated in the questionnaire. The respondents were divided according to the country of current practice: national (Iraqi), regional (Middle Eastern), and international participants. Out of 144 respondents, 51.4% percent of the participants were international, while 40.3% were Iraqis, and 8.3% were from the Middle East. The need for dental radiography in all dental extraction procedures was reported in the majority of responses (n = 86). Only 11 dentists think there is no necessity for radiographic examination before conventional extraction. The chi-square test showed a highly significant relationship between the country of current practice and the need for X-ray examination for conventional dental extraction (P < 0.01). Seventy-six dentists prefer periapical radiographs. Thirty-five preferred orthopantomography. A highly significant relationship was found between the country of practice and the X-ray technique (P < 0.01).

Conclusion

The study showed that there is no universally adopted protocol regarding the use of dental radiography before dental extraction. The country of practice appears to govern the dentists' decisions regarding the need for an X-ray and the type of radiography prior to dental extraction. Periapical radiographs for posterior teeth seem to be the preferable choice before dental extraction.

A novel method of objectively detecting tooth ankylosis using cone-beam computed tomography: A laboratory study

Purpose

The aim of this study was to objectively detect simulated tooth ankylosis using a novel method involving cone-beam computed tomography (CBCT).

Materials and Methods

Tooth ankylosis was simulated in single-rooted human permanent teeth, and CBCT scans were acquired at different current levels (5, 6.3, and 8 mA) and voxel sizes (0.08, 0.125, and 0.2). In axial reconstructions, a line of interest was perpendicularly placed over the periodontal ligament space of 21 ankylosed and 21 non-ankylosed regions, and the CBCT grey values of all voxels along the line of interest were plotted against their corresponding X-coordinates through a line graph to generate a profile. The image contrast was increased by 30% and 60% and the profile assessment was repeated. The internal area of the resulting parabolas was obtained from all images and compared between ankylosed and non-ankylosed regions under different contrast enhancement conditions, voxel sizes, and mA levels using multi-way analysis of variance with the Tukey post hoc test (α=0.05).

Results

The internal area of the parabolas of all non-ankylosed regions was significantly higher than that of the ankylosed regions (P<0.05). Contrast enhancement led to a significantly greater internal area of the parabolas of non-ankylosed regions (P<0.05). Overall, voxel size and mA did not significantly influence the internal area of the parabolas (P>0.05).

Conclusion

The proposed novel method revealed a relevant degree of applicability in the detection of simulated tooth ankylosis; increased image contrast led to greater detectability.

Three-Dimensional Distance Mapping Method to Evaluate Mandibular Symmetry and Morphology of Adults with Unilateral Premolar Scissors Bite

(1) Objective: This study aimed to evaluate the association between unilateral premolar scissors bite and mandibular symmetry of adults via the 3D distance mapping method. (2) Methods: A total of 53 cone-beam computed tomography (CBCT) images of adults with unilateral premolar scissors bite were set as study samples. A total of 53 age- and sex-matched samples without scissors bite were in the control group. Three-dimensional mandibular models and seven mandibular functional units, including condylar process (Co), coronoid process (Cr), mandibular ramus (Ra), mandibular angle (Ma), alveolar process (Ap), mandibular body (Mb), and chin process (Ch) were constructed and mirrored. After superimposition of the original and the mirrored models, 3D distance maps and deviation analysis were performed to evaluate the mandibular symmetry and morphology. (3) Results: In the study group, the matching percentages of the entire mandible (50.79 ± 10.38%), Ap (67.00 ± 12.68%), Mb (66.62 ± 9.44%), Ra (62.52 ± 11.00%), Ch (80.75 ± 9.86%), and Co (62.78 ± 13.56) were lower than that of the entire mandible (58.60 ± 5.52) (p < 0.01), Ap (73.83 ± 8.88%) (p < 0.01), Mb (72.37 ± 8.69%) (p < 0.01), Ra (68.60 ± 7.56%) (p < 0.01), Ch (85.23 ± 6.80%) (p < 0.01), and Co (67.58 ± 10.32%) (p < 0.05) in the control group. However, Cr and Ma showed no significant difference (p > 0.05). (4) Conclusions: The 3D distance mapping method provided a qualitative and quantitative mandibular symmetry and morphology assessment. Mandibular asymmetry was found in adults with unilateral premolar scissors bites. Mandibular functional units, including the alveolar process, mandibular body, mandibular ramus, chin process, and condylar process, showed significant differences, while no significant difference was observed in the coronoid process and mandibular angle.

Evaluation of the association between osteoporosis and periodontitis in postmenopausal women: A clinical and radiographic study

Background

This study aimed to assess the relationship between the osteoporotic condition and periodontitis in postmenopausal women.

Materials and Methods

Ninety-four women aged 50-80 years were studied in this cross-sectional study. Bone mineral density (BMD) of lumbar vertebra BMD (LBMD), total hip BMD (HBMD), and neck of femur BMD (NBMD) was assessed using standardized dual-energy X-ray absorptiometry (DXA) (normal: T-score ≥-1, osteopenic: -2.5 ≤ t-score <-1, osteoporotic: T-score <-2.5). Bleeding point index (BI), O'Leary plaque index (PI), and clinical attachment loss (CAL) were recorded. Cementoenamel junction, alveolar-crest distance (CEJ-AC) was measured from cone-beam computed tomography images. Periodontitis severity was represented by CAL and CEJ-AC distance. One-way analysis of variance followed by Post hoc Tukey was performed for examining differences among the groups for different variables. Pearson correlation coefficient® and backward regression analysis were used to investigate the effect of confounding variables on CEJ-AC as the dependent variable. Significance was considered at P < 0.05.

Results

Mean CEJ-AC was significantly higher in the osteoporotic and osteopenic groups compared to the normal group (P = 0.001). There was a significant positive correlation between CEJ-AC and NBMD and LBMD (P < 0.001). The associations between LBMD and CEJ-AC existed even after adjusting for confounding factors (P = 0.002). The differences in BI, PI, and CAL were not statistically different between the groups (P > 0.05).

Conclusion

Although osteoporosis is not the main cause of periodontitis, it can indirectly affect periodontal status by increasing CEJ-AC. Early diagnosis of osteoporosis followed by early referral to a dentist for the treatment of potential existing periodontal diseases is important to avoid complications among postmenopausal women.

A two-stage deep learning architecture for radiographic staging of periodontal bone loss

Background

Radiographic periodontal bone loss is one of the most important basis for periodontitis staging, with problems such as limited accuracy, inconsistency, and low efficiency in imaging diagnosis. Deep learning network may be a solution to improve the accuracy and efficiency of periodontitis imaging staging diagnosis. This study aims to establish a comprehensive and accurate radiological staging model of periodontal alveolar bone loss based on panoramic images.

Methods

A total of 640 panoramic images were included, and 3 experienced periodontal physicians marked the key points needed to calculate the degree of periodontal alveolar bone loss and the specific location and shape of the alveolar bone loss. A two-stage deep learning architecture based on UNet and YOLO-v4 was proposed to localize the tooth and key points, so that the percentage of periodontal alveolar bone loss was accurately calculated and periodontitis was staged. The ability of the model to recognize these features was evaluated and compared with that of general dental practitioners.

Results

The overall classification accuracy of the model was 0.77, and the performance of the model varied for different tooth positions and categories; model classification was generally more accurate than that of general practitioners.

Conclusions

It is feasible to establish deep learning model for assessment and staging radiographic periodontal alveolar bone loss using two-stage architecture based on UNet and YOLO-v4.

Effect of Low-Level Laser Therapy on Bone Formation in Rapid Palatal Expansion: A Systematic Review

Introduction: Crossbite is a common malocclusion with a 7-23% prevalence rate. Treatment is based on the expansion of the mid-palatal suture (MPS) with Rapid Palatal Expansion(RPE) followed by a retention period to reach new bone maturation, enough to maintain the results stable. This systematic review was conducted to evaluate the effectiveness of low-level laser therapy (LLLT) in increasing bone formation in MPS. Methods: This article was written by the PRISMA checklist. Electronically, 3 databases, namely PubMed, Scopus, and Embase, were searched with the keywords selected based on PICO. Time (2010-2021) and language restrictions were performed. Results: 528 articles, out of which 374 studies were screened, were found, and 9 full-text articles were subsequently included considering these inclusion criteria: randomized clinical trial (RCT) that examines the efficacy of LLLT in rapid palatal expansion (RPE), age under 15 years, non-surgical RPE with a tooth-supported appliance, and low-intensity laser application. Finally, 4 articles were appraised by Cochrane version 5.2.0 with 7 domains. 3 of 4 articles showed LLLT has a significant impact on bone formation. One of them showed no significant difference in pain perception and bone density between the laser and non-laser groups. Conclusion: While many studies have assessed the effect of LLLT on bone formation in animal models, high-quality clinical trials are missing in this regard. The available clinical trials suggest a positive effect of LLLT on sutural bone formation after RPE.

Diagnosis and Management of Furcation Lesions in Dogs - A Review

The furcation is the anatomic area where the roots divide on a multirooted tooth. Periodontal disease causing alveolar bone loss can lead to furcation lesions of various stages. Once furcation involvement has occurred, the area can be more difficult to clean or treat due to the complex anatomy and morphology of furcations. Teeth with short root trunks, longer tooth roots, and roots with wide furcation entrance areas/degrees of separation and wide root divergence are considered better candidates for long term maintenance. Dog teeth possess many of these advantageous anatomic features compared to human teeth. Treatment options for teeth with furcation lesions include: closed debridement, open debridement, furcation plasty, tunneling, partial tooth or root resection, root separation (hemisection or trisection), regenerative therapies, or exodontia. There are many factors to consider in determining treatment options. The favorable and unfavorable characteristics for maintenance of teeth with furcation lesions are summarized. Home care and ongoing professional care are important aspects of periodontal disease control for any patient. Studies of systemic and local antibiotic therapies in human patients have not demonstrated reduction of furcation stages, and probiotic effects at furcation sites have not been specifically examined. Human review studies show that most molar teeth once deemed "hopeless" due to stage 3 furcation lesions can be maintained for at least 5 to 15 years with supportive periodontal therapy. Similar long term studies in dogs are needed to improve the evidence-based management of canine patients with furcation lesions.

Testing regression and mean model approaches to facial soft-tissue thickness estimation

Average facial soft-tissue thickness (FSTT) databanks are continuously developed and applied within craniofacial identification. This study considered and tested a subject-specific regression model alternative for estimating the FSTT values for oral midline landmarks using skeletal projection measurements. Measurements were taken from cone-beam computed tomography scans of 100 South African individuals (60 male, 40 female; M_age = 35 years). Regression equations incorporating sex categories were generated. This significantly improved the goodness-of-fit (r²-value). Validation tests compared the constructed regression models with mean FSTT data collected from this study, existing South African FSTT data, a universal total weighted mean approach with pooled demographic data and collection techniques and a regression model approach that uses bizygomatic width and maximum cranial breadth dimensions. The generated regression equations demonstrated individualised results, presenting a total mean inaccuracy (TMI) of 1.53 mm using dental projection measurements and 1.55 mm using cemento-enamel junction projection measurements. These slightly outperformed most tested mean models (TMI ranged from 1.42 to 4.43 mm), and substantially outperformed the pre-existing regression model approach (TMI = 5.12 mm). The newly devised regressions offer a subject-specific solution to FSTT estimation within a South African population. A continued development in sample size and validation testing may help substantiate its application within craniofacial identification.

Automating Periodontal bone loss measurement via dental landmark localisation

PURPOSE

Periodontitis is the sixth most prevalent disease worldwide and periodontal bone loss (PBL) detection is crucial for its early recognition and establishment of the correct diagnosis and prognosis. Current radiographic assessment by clinicians exhibits substantial interobserver variation. Computer-assisted radiographic assessment can calculate bone loss objectively and aid in early bone loss detection. Understanding the rate of disease progression can guide the choice of treatment and lead to early initiation of periodontal therapy.

METHODOLOGY

We propose an end-to-end system that includes a deep neural network with hourglass architecture to predict dental landmarks in single, double and triple rooted teeth using periapical radiographs. We then estimate the PBL and disease severity stage using the predicted landmarks. We also introduce a novel adaptation of MixUp data augmentation that improves the landmark localisation.

RESULTS

We evaluate the proposed system using cross-validation on 340 radiographs from 63 patient cases containing 463, 115 and 56 single, double and triple rooted teeth. The landmark localisation achieved Percentage Correct Keypoints (PCK) of 88.9%, 73.9% and 74.4%, respectively, and a combined PCK of 83.3% across all root morphologies, outperforming the next best architecture by 1.7%. When compared to clinicians' visual evaluations of full radiographs, the average PBL error was 10.69%, with a severity stage accuracy of 58%. This simulates current interobserver variation, implying that diverse data could improve accuracy.

CONCLUSIONS

The system showed a promising capability to localise landmarks and estimate periodontal bone loss on periapical radiographs. An agreement was found with other literature that non-CEJ (Cemento-Enamel Junction) landmarks are the hardest to localise. Honing the system's clinical pipeline will allow for its use in intervention applications.

Clinical and radiographic evaluation of 0.8% hyaluronic acid as an adjunct to open flap debridement in the treatment of periodontal intrabony defects: randomized controlled clinical trial

OBJECTIVES

Present study aimed to evaluate and compare the clinical and radiographic efficacy of 0.8% hyaluronic acid (HA) gel as an adjunct to open flap debridement (OFD) versus open flap debridement (OFD) alone in the treatment of periodontal intrabony defects.

MATERIALS AND METHODS

This randomized, controlled, split-mouth, clinical trial included 20 chronic periodontitis (stage II or III (grades A to B)) patients, having at least two contralateral intrabony defects. Forty bilateral intrabony defects (20 in each group) were randomly divided into test (0.8% HA gel + OFD) and control (OFD + placebo) groups. Clinical parameters evaluated at baseline, 6-months, and 12-months were plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL), and gingival recession (GR). Using cone beam computed tomography (CBCT), radiographic parameters were evaluated at baseline and 12 months. This included bone defect fill (DF), alveolar crest changes (ACC), and defect resolution (DR). CAL served as the primary outcome variable.

RESULTS

After 12 months, the test group showed significantly greater CAL gain (5.1 ± 1.2 versus 4.05 ± 1.19 mm) and bone defect fill (DF) (5.67 ± 2.01 versus 4.49 ± 1.78 mm) compared to the control group. Mean PD reduction in the test group (5.3 ± 1.2 versus 4.35 ± 0.81 mm) was statistically significant compared to the control group at 12-month period. The control group showed statistically significant increase in GR (1.2 ± 0.76 versus 0.7 ± 0.73 mm) compared to the test group after 12 months.

CONCLUSION

Application of hyaluronic acid gel in conjunction with open flap debridement resulted in enhanced clinical and radiographic outcomes compared to open flap debridement alone.

CLINICAL RELEVANCE

Adjunctive application of HA gel in open flap debridement may improve clinical and radiographic outcomes.

CLINICAL TRIAL REGISTERED NUMBER

CTRI/2018/03/012334.

Two decades of research on CBCT imaging in DMFR - an appraisal of scientific evidence

OBJECTIVE

This article aims to appraise how scientific evidence related to CBCT has changed over the years, based on levels of evidence and diagnostic efficacy.

METHODS

A general search strategy was used in different databases (Pubmed, Embase, and Web of Science) to identify systematic reviews (SRs) on CBCT until November of 2020. The SRs included were divided according to different specialties of dentistry. A critical review of the articles was made, describing the level of evidence and efficacy.

RESULTS

In total, 75 articles were selected. There was an increase in the number of SRs on CBCT from 2014 onwards, as 83% of the SRs on this topic were published after 2013, and 72% between 2016 and to date. Twenty SRs (27%) performed meta-analysis. Only 28% of the SRs provided a detailed description of CBCT protocols. According to SR evidence, almost all specialties of dentistry have advanced concomitantly with the introduction of CBCT. The majority of SRs were related to clinical applications (level 2 of efficacy), followed by technical parameters (level 1 of efficacy). Only some CBCT models were mentioned in the SRs selected.

CONCLUSION

Over the course of 20 years, SRs related to CBCT applications for a broad range of dental specialties have been published, with the vast majority of studies at levels 1 and 2 of diagnostic efficacy. Not all CBCT models available on the market have been scientifically validated. At all times, one should remain cautious as such not to simply extrapolate in vitro results to the clinical setting. Also, considering the wide variety of CBCT devices and protocols, reported results should not be overstated or generalized, as outcomes often refer to specific CBCT devices and protocols.

Cone beam computed tomography (CBCT) in periodontal diseases: a Systematic review based on the efficacy model

Background

Periodontal diseases are prevalent among adult populations. Its diagnosis depends mainly on clinical findings supported by radiographic examinations. In previous decades, cone beam computed tomography has been introduced to the dental field. The aim of this study was to address the diagnostic efficacy of cone-beam computed tomographic (CBCT) imaging in periodontics based on a systematic search and analysis of the literature using the hierarchical efficacy model.

Methods

A systematic search of electronic databases such as PubMed, Scopus, Web of Science, and Cochrane was conducted in February 2019 to identify studies addressing the efficacy of CBCT imaging in Periodontics. The identified studies were subjected to pre-identified inclusion criteria followed by an analysis using a hierarchical model of efficacy (model) designed for an appraisal of the literature on diagnostic imaging modality. Four examiners performed the eligibility and quality assessment of relevant studies and consensus was reached in cases where disagreement occurred.

Results

The search resulted in 64 studies. Of these, 34 publications were allocated to the relevant level of efficacy and quality assessments wherever applicable. The overall diagnostic accuracy of the included studies showed a low or moderate risk of bias and applicability concerns in the use of CBCT. In addition, CBCT is accurate in identifying periodontal defects when compared to other modalities. The studies on the level of patient outcomes agreed that CBCT is a reliable tool for the assessment of outcomes after the treatment of periodontal defects.

Conclusion

CBCT was found to be beneficial and accurate in cases of infra-bony defects and furcation involvements.

Comparison of cartilage and bone morphological models of the ankle joint derived from different medical imaging technologies

Background

Accurate geometrical models of bones and cartilage are necessary in biomechanical modelling of human joints, and in planning and designing of joint replacements. Image-based subject-specific model development requires image segmentation, spatial filtering and 3-dimensional rendering. This is usually based on computed tomography (CT) for bone models, on magnetic resonance imaging (MRI) for cartilage models. This process has been reported extensively in the past, but no studies have ever compared the accuracy and quality of these models when obtained also by merging different imaging modalities. The scope of the present work is to provide this comparative analysis in order to identify optimal imaging modality and registration techniques for producing 3-dimensional bone and cartilage models of the ankle joint.

Methods

One cadaveric leg was instrumented with multimodal markers and scanned using five different imaging modalities: a standard, a dual-energy and a cone-beam CT (CBCT) device, and a 1.5 and 3.0 Tesla MRI devices. Bone, cartilage, and combined bone and cartilage models were produced from each of these imaging modalities, and registered in space according to matching model surfaces or to corresponding marker centres. To assess the quality in overall model reconstruction, distance map analyses were performed and the difference between model surfaces obtained from the different imaging modalities and registration techniques was measured.

Results

The registration between models worked better with model surface matching than corresponding marker positions, particularly with MRI. The best bone models were obtained with the CBCT. Models with cartilage were defined better with the 3.0 Tesla than the 1.5 Tesla. For the combined bone and cartilage models, the colour maps and the numerical results from distance map analysis (DMA) showed that the smallest distances and the largest homogeneity were obtained from the CBCT and the 3.0 T MRI via model surface registration.

Conclusions

These observations are important in producing accurate bone and cartilage models from medical imaging and relevant for applications such as designing of custom-made ankle replacements or, more in general, of implants for total as well as focal joint replacements.

Deep Learning for the Radiographic Detection of Periodontal Bone Loss

We applied deep convolutional neural networks (CNNs) to detect periodontal bone loss (PBL) on panoramic dental radiographs. We synthesized a set of 2001 image segments from panoramic radiographs. Our reference test was the measured % of PBL. A deep feed-forward CNN was trained and validated via 10-times repeated group shuffling. Model architectures and hyperparameters were tuned using grid search. The final model was a seven-layer deep neural network, parameterized by a total number of 4,299,651 weights. For comparison, six dentists assessed the image segments for PBL. Averaged over 10 validation folds the mean (SD) classification accuracy of the CNN was 0.81 (0.02). Mean (SD) sensitivity and specificity were 0.81 (0.04), 0.81 (0.05), respectively. The mean (SD) accuracy of the dentists was 0.76 (0.06), but the CNN was not statistically significant superior compared to the examiners (p = 0.067/t-test). Mean sensitivity and specificity of the dentists was 0.92 (0.02) and 0.63 (0.14), respectively. A CNN trained on a limited amount of radiographic image segments showed at least similar discrimination ability as dentists for assessing PBL on panoramic radiographs. Dentists’ diagnostic efforts when using radiographs may be reduced by applying machine-learning based technologies.

Ex vivo comparison of CBCT and digital periapical radiographs for the quantitative assessment of periodontal defects

OBJECTIVES

Accurate imaging is essential for effective treatment planning in periodontology. The aim of this ex vivo study was to investigate the accuracy of cone beam computed tomography (CBCT) and digital periapical radiographs (PA) in imaging periodontal defects. Hypotheses are: 1. That CBCT is a more accurate method than PA concerning vertical measurements of periodontal bone defects2. That CBCT itself is an accurate method to describe vertical periodontal bone loss MATERIAL AND METHODS: In this study, 117 periodontal defects from 10 human cadavers were investigated radiographically by CBCT and PA by one calibrated observer. Afterwards the vertical bone loss was measured with a periodontal probe by the same calibrated observer. Differences between radiographic and clinical measurements were calculated and analyzed. Bland-Altmann plots including 95% limits of agreement were calculated.

RESULTS

The 95% limits of agreement ranged from 3.29 to -3.27 mm between clinical measurements and measurements in PAs, and from 2.13 to -1.97 mm in CBCTs. The mean difference between clinical and radiographic measurements was 0.0009 mm for PA and 0.0835 mm for CBCT.

CONCLUSIONS

When comparing the clinical measurements, CBCT had a higher agreement and less deviations than PAs, and CBCT seems to be an accurate method to describe vertical periodontal bone loss.

CLINICAL RELEVANCE

Accurate description of defects is helpful for accurate treatment planning.