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

DentalSegmentator: Robust open source deep learning-based CT and CBCT image segmentation

OBJECTIVES

Segmentation of anatomical structures on dento-maxillo-facial (DMF) computed tomography (CT) or cone beam computed tomography (CBCT) scans is increasingly needed in digital dentistry. The main aim of this research was to propose and evaluate a novel open source tool called DentalSegmentator for fully automatic segmentation of five anatomical structures on DMF CT and CBCT scans: maxilla/upper skull, mandible, upper teeth, lower teeth, and the mandibular canal.

METHODS

A retrospective sample of 470 CT and CBCT scans was used as a training/validation set. The performance and generalizability of the tool was evaluated by comparing segmentations provided by experts and automatic segmentations in two hold-out test datasets: an internal dataset of 133 CT and CBCT scans acquired before orthognathic surgery and an external dataset of 123 CBCT scans randomly sampled from routine examinations in 5 institutions.

RESULTS

The mean overall results in the internal test dataset (n = 133) were a Dice similarity coefficient (DSC) of 92.2 ± 6.3 % and a normalised surface distance (NSD) of 98.2 ± 2.2 %. The mean overall results on the external test dataset (n = 123) were a DSC of 94.2 ± 7.4 % and a NSD of 98.4 ± 3.6 %.

CONCLUSIONS

The results obtained from this highly diverse dataset demonstrate that this tool can provide fully automatic and robust multiclass segmentation for DMF CT and CBCT scans. To encourage the clinical deployment of DentalSegmentator, the pre-trained nnU-Net model has been made publicly available along with an extension for the 3D Slicer software.

CLINICAL SIGNIFICANCE

DentalSegmentator open source 3D Slicer extension provides a free, robust, and easy-to-use approach to obtaining patient-specific three-dimensional models from CT and CBCT scans. These models serve various purposes in a digital dentistry workflow, such as visualization, treatment planning, intervention, and follow-up.

A large animal model of periodontal defects in bisphosphonate-related osteonecrosis of the jaw: a comparison of clinical and radiological findings

PURPOSE

The objective of this study was to demonstrate the suitability of cone-beam computed tomography (CBCT) for in vivo research in periodontology, with implications for oral implantology, facial traumatology, and all disciplines involved in treating patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ).

METHODS

Halves of the jaws of 9 Swiss mountain sheep, assigned to a control group (n=3), an osteoporosis group (n=3) and a zoledronate-exposed group (n=3), were examined. Clinical and radiological evaluations were conducted using CBCT imaging to assess whether periodontitis and bone defects were observed to a significant extent after surgical tooth extraction.

RESULTS

In contrast to the control and osteoporosis groups, the zoledronate group exhibited significant residual bone defects following tooth extraction (P<0.05). CBCT more objectively revealed these effects and enabled a numerical evaluation (in mm3).

CONCLUSIONS

Evaluating residual defects in bone blocks from sheep using CBCT analysis was found to be as effective as a clinical examination conducted by specialists in oral and maxillofacial surgery. The strong correlation between radiological findings and clinical conditions suggests that CBCT may become increasingly important in the future, particularly in periodontological research related to BRONJ.

Multidimensional 3D-Printed Scaffolds and Regeneration of Intrabony Periodontal Defects: A Systematic Review

BACKGROUND

The utilization of regenerative techniques in periodontology involves tailoring tissue engineering principles to suit the oral cavity's unique environment. Advancements in computer-assisted technology, specifically utilizing cone beam computed tomography (CBCT), enabled the fabrication of 3D-printed scaffolds. The current review aims to explore whether 3D-printed scaffolds are effective in promoting osteogenesis in patients with periodontal defects.

METHODS

A thorough exploration was undertaken across seven electronic databases (PubMed, Scopus, ScienceDirect, Google Scholar, Cochrane, Web of Science, Ovid) to detect pertinent research in accordance with specified eligibility criteria, aligning with the PRISMA guidelines. Two independent reviewers undertook the screening and selection of manuscripts, executed data extraction, and evaluated the bias risk using the Newcastle-Ottawa Scale for non-randomized clinical trials and SYRCLE's risk of bias tool for animal studies.

RESULTS

Initially, 799 articles were identified, refined by removing duplicates. After evaluating 471 articles based on title and abstract, 18 studies remained for full-text assessment. Eventually, merely two manuscripts fulfilled all the eligibility criteria concerning human trials. Both studies were prospective non-randomized clinical trials. Moreover, 11 animal studies were also included.

CONCLUSIONS

The use of multidimensional, 3D-printed, customized scaffolds appears to stimulate periodontal regeneration. While the reported results are encouraging, additional studies are required to identify the ideal characteristics of the 3D scaffold to be used in the regeneration of periodontal tissue.

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.

A Cone Beam CT Study on the Correlation between Crestal Bone Loss and Periapical Disease

The aim of this study was to determine whether the degree of bone loss around teeth can be linked to the loss of vitality of adjacent teeth and periapical disease, which necessitates root canal treatments. Three hundred and twenty-one full maxilla cone-beam computed tomography scans were examined. The parameters investigated included the degree of crestal bone loss in relation to the cementoenamel junction, the presence/absence of apical periodontitis, and the presence/absence of root canal treatments. Out of the 2001 teeth examined, 696 (34.8%) showed evidence of crestal bone loss. The degree of crestal bone loss was classified as mild, moderate, or severe. A significant association (p < 0.001) was found between the presence of crestal bone loss around a tooth and root canal treatment of that tooth. It was found that it is more likely for teeth with crestal bone loss to be root canal treated compared to teeth with existing root canal treatment and healthy crestal bone levels. Furthermore, teeth with buccal or lingual crestal bone loss were significantly associated with a higher rate of periapical disease than teeth without crestal bone loss (p < 0.001). CBCT identified the severity of bone loss on all surfaces of the teeth, and the most common presentation was bone loss to the mid-root level. Teeth with crestal bone loss were significantly more likely to be associated with a higher rate of periapical disease. Teeth with crestal bone loss were more likely to be root treated than teeth with healthy crestal bone levels.

Comparison between Conventional Modality Versus Cone-Beam Computer Tomography on the Assessment of Vertical Furcation in Molars

This study aimed to assess the accuracy of diagnosis of vertical furcation subclass in molars using periapical radiographs (PAs) and clinical chartings compared against cone-beam computer tomography (CBCT) as the gold standard. The protocol involved examiners with different levels of experience. This retrospective radiographic study retrieved 40 molar teeth with full periodontal chartings, PAs, and CBCT records. Fifteen examiners with different levels of experience evaluated the PAs and periodontal chartings to assess the vertical depth of furcation and, thus, the vertical subclassification. CBCT was used as the gold standard for comparison. The accuracy of vertical furcal depth measured was assessed together with the accuracy of vertical subclassification assignment. The reliability of the conventional diagnostic modality among the examiners was also evaluated. A linear mixed model adjusted for the CBCT vertical furcal depth measurement was constructed to determine if tooth position, horizontal furcation distribution, and examiner experience level affect the bias in the vertical depth of furcation measurement. The reliability of the conventional periodontal diagnostic method in measuring vertical furcal depth was found to be fair, while vertical subclass assignment was moderate. Significantly better reliability during subclass assignment was found with mandibular molars (p < 0.001) and in maxillary molars with isolated buccal class II furcation. Within the study’s limitations, conventional periodontal diagnostics based on periapical radiographs and clinical periodontal chartings appear to be in poor to fair agreement with CBCT (gold standard) when measuring the vertical depth of furcation. Examiners with the least experience were more prone to bias when estimating the vertical furcal depth.

Accuracy and Reliability of CBCT Compared to Clinical Probing in Detection of Trifurcation Defects: An In Vivo Study

Background

Furcation defects are areas of pathological bone resorption in multirooted teeth. The aim of the study was to compare the measurements of trifurcation bone loss, measured using CBCT, versus clinical measurements in order to evaluate the efficacy of CBCT as an adjunctive diagnostic tool. Material and Methods. The included patients had both CBCT scans for maxillary molars and completed periodontal charts. Clinical examination consisted of probing and detection of vertical and horizontal furcation defects. These were measured and recorded. CBCT measurements were then evaluated using the linear measuring tool in Carestream imaging software (Carestream, Rochester, USA) and iCAT (Imaging Sciences, Hatfield, USA). These measurements of the CBCT images were then documented and compared to clinical findings. The two examiners were blinded to each other's measurements.

Results

The most common tooth with a detected furcation defect was tooth #2 (31.7%), followed by tooth #15 (26.8%) and #3 (21.9%). The least common tooth with a detected furcation defect was #14 (19.5%). The mean values of buccal furcation for clinical and CBCT measurements were 3.01 mm and 2.6 mm, respectively. The measurements of mesial furcation were 2.5 mm and 2.2 mm for CBCT. The distal measurement of clinical examination was 2.7 mm and for CBCT was 2.44 mm.

Conclusion

CBCT can be used as an adjunct to clinical furcation measurements and adds useful diagnostic information to assess trifurcation defects. In addition, CBCT limited field of view (FOV) can provide relatively high-resolution images at a reduced dose that is comparable to two-dimensional imaging.

Association between root taper and root proximity of single-rooted teeth with periodontitis: a cone-beam computed tomography based study

This study aimed to determine the association between the root taper and proximity of single-rooted teeth with periodontitis using cone-beam computed tomography (CBCT). CBCT images of 362 single-rooted teeth from 37 patients were evaluated. This case-control study analyzed 17 participants with stage II and III periodontitis, (n = 161 teeth, periodontitis group) and 20 participants with healthy periodontium (n = 201 teeth, control group). Multiplanar reconstructions were used for proximity measurements, and cross-sectional images for calculating the angle of the root tapers. Root proximity, root length, and root taper were measured. Multivariate binary logistic regression analysis was used to determine association with periodontitis. In the periodontitis group, the upper lateral root-taper was 18.33° ± 3.25° and was significantly higher when compared to the control group (p = 0.001). The root taper of the lateral incisor was associated with the diagnosis of periodontitis (p = 0.01) with an odds ratio of 1.541 according to regression analysis. Root length was also identified as a potential protective parameter. The risk of being diagnosed with periodontitis decreases when root length increases by 0.785 times (p = 0.043). Upper canines in the periodontitis group presented shorter root lengths (p = 0.039) and higher root tapers (p = 0.01). Also, mandibular canines were closer form adjacent teeth in the periodontitis group (p = 0.042). This study indicated that short-root and increased root-taper at specific teeth could be considered as risk indicators for periodontitis.

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.

Digital three-dimensional visualization of intrabony periodontal defects for regenerative surgical treatment planning

Background

In the regenerative treatment of intrabony periodontal defects, surgical strategies are primarily determined by defect morphologies. In certain cases, however, direct clinical measurements and intraoral radiographs do not provide sufficient information on defect morphologies. Therefore, the application of cone-beam computed tomography (CBCT) has been proposed in specific cases. 3D virtual models reconstructed with automatic thresholding algorithms have already been used for diagnostic purposes. The aim of this study was to utilize 3D virtual models, generated with a semi-automatic segmentation method, for the treatment planning of minimally invasive periodontal surgeries and to evaluate the accuracy of the virtual models, by comparing digital measurements to direct intrasurgical measurements.

Methods

Four patients with a total of six intrabony periodontal defects were enrolled in the present study. Two months following initial periodontal treatment, a CBCT scan was taken. The novel semi-automatic segmentation method was performed in an open-source medical image processing software (3D Slicer) to acquire virtual 3D models of alveolar and dental structures. Intrasurgical and digital measurements were taken, and results were compared to validate the accuracy of the digital models. Defect characteristics were determined prior to surgery with conventional diagnostic methods and 3D virtual models. Diagnostic assessments were compared to the actual defect morphology during surgery.

Results

Differences between intrasurgical and digital measurements in depth and width of intrabony components of periodontal defects averaged 0.31 ± 0.21 mm and 0.41 ± 0.44 mm, respectively. In five out of six cases, defect characteristics could not be assessed precisely with direct clinical measurements and intraoral radiographs. 3D models generated with the presented semi-automatic segmentation method depicted the defect characteristics correctly in all six cases.

Conclusion

It can be concluded that 3D virtual models acquired with the described semi-automatic segmentation method provide accurate information on intrabony periodontal defect morphologies, thus influencing the treatment strategy. Within the limitations of this study, models were found to be accurate; however, further investigation with a standardized validation process on a large number of participants has to be conducted.

Facial Flatness Indices: A Comparison of Two Methods of Assessment

OBJECTIVES

The objective of the study was to evaluate and compare facial flatness indices calculated from the trigonometric formula as opposed to those generated from the direct measurements on three-dimensional radiographs.

MATERIAL AND METHODS

A total of 322 cone-beam computed tomography radiographs were digitized and three facial indices (frontal, simotic, and zygomaxillary) were assessed in two different methods and compared between different groups.

RESULTS

There was a discrepancy between facial flatness indices generated from the two different approaches. The highest difference was seen in the findings of the simotic index and the lowest for the zygomaxillary index. No statistically significant difference was displayed in the three formula-generated flatness indices between males and females and between growing and non-growing subjects (P > 0.05). The zygomaxillary index was the only measurement revealing no statistically significant difference in Class III sagittal malocclusions (t = -0.5 P = 0.621). The orthodontic application would yield to the same interpretations for both ways of indices calculation.

CONCLUSION

The validity of the trigonometric formula used to appraise facial flatness indices might be questionable. The zygomaxillary index could be more clinically considered compared to the frontal and simotic indices.