Updates on ultrasound research in implant dentistry: a systematic review of potential clinical indications

Ridge augmentation planning, wound healing evaluation, and peri-implant tissue phenotype assessment with ultrasonography: A case report

BACKGROUND

Ridge regeneration for implant therapy requires comprehensive site evaluation and wound healing monitoring. This case report aimed to demonstrate ultrasound (US) can image soft and hard tissues for surgical planning and assess longitudinal outcomes.

METHODS AND RESULTS

US was used in a patient planned for ridge augmentation to evaluate soft tissue thickness, location of muscle attachment, and hard tissue defect features presurgically. US were obtained at 1, 2.5, and 5 months afterward to assess tissue healing. Preoperatively, US showed ∼2.5 mm and ∼0.8 mm soft tissue thickness on the facial and lingual sides, respectively. The crestal bone width was ∼2 mm, with severe facial bone deficiency and high muscle attachment. US showed wound approximation and ridge width gain to 4.5 and 4.0 mm at 1 and 5 months, respectively. US tissue perfusion increased to ∼two-fold and ∼4-fold at 1 and 2.5 months and reduced below the baseline at 5 months. An implant with simultaneous bone augmentation was performed accordingly. Tissue phenotype around the implant was measured on US images at 1-year visit.

CONCLUSIONS

This case report demonstrated that US parameters could be valuable for planning and wound healing outcome assessment of ridge augmentation in clinical as well as research settings.

KEY POINTS

Why is this case new information? Novel high-resolution, chairside ultrasound was proposed to facilitate treatment planning and wound healing outcome assessment of ridge augmentation in clinical as well as research settings. What are the keys to successful use of this technology? Proper training in imaging acquisition and interpretation Adhere to high-level disinfection protocol Patient education and explanation What are the primary limitations to success in using this technology? Investment in this technology Learning curve in imaging acquisition and reading Insurance reimbursement strategy.

Influencing factors and evaluation methods for early stability of immediate implant

At present, implant restoration has become a hot research topic in the field of prosthodontics. The in-depth studies of new materials and new technologies enable immediate implantation, immediate and early loading to be realized, which meets the needs of patients for shortening the course of implant restoration and obtaining better aesthetic effects. However, compared with the traditional delayed implantation technology, it is equally challenging for clinicians how to achieve and even improve the initial and long-term stability of implants in order to raise the success rate of implant restoration. The initial stability of the implant is influenced by a combination of factors, including the implant, the patient's condition, and the surgical procedure. Recently, there have been a lot of studies on the influencing factors and common research methods for immediate implant stability and bone healing. Summarizing and analyzing them can provide reference for preoperative evaluation, surgical plan and loading timing of immediate implant restoration in the later stage.

The use of digital technologies in peri-implant soft tissue augmentation - A narrative review on planning, measurements, monitoring and aesthetics

OBJECTIVE

To identify the different uses and modalities of digital technologies to diagnose, plan and monitor peri-implant soft tissue conditions and aesthetics.

METHODS

A comprehensive narrative review of pertinent literature was conducted, critically appraising key digital technologies that may assist peri-implant soft tissue augmentation and assessment. An electronic search on four databases including studies published prior to 1st July 2023 was performed and supplemented by a manual search.

RESULTS

Predominantly, tools such as cone beam computed tomography (CBCT), intraoral scanning (iOS), intraoral ultrasonography and digital spectrophotometry were commonly to assess and monitor peri-implant soft tissues. The main clinical and research applications included: (i) initial assessment of mucosal thickness, supra-crestal tissue height and keratinized mucosa width, (ii) evaluation of peri-implant soft tissue health and inflammation, (iii) monitoring profilometric changes and midfacial mucosal margin stability over time and (iv) aesthetic evaluation through colour assessment. While evidence for some digital tools may be limited, the integration of digital technologies into peri-implant soft tissue management holds great promise. These technologies offer improved precision, comfort and speed in assessment, benefiting both patients and clinicians.

CONCLUSION

As digital technologies progress, their full potential in peri-implant soft tissue augmentation and their value will become more evident with ongoing research. Embracing these innovations and their potential benefits is recommended to ensure that during progress in implant dentistry, patient care is not hindered.

Use of ultrasound imaging for assessment of the periodontium: A systematic review

The objective of this study was to systematically review the literature regarding diagnostic applications of ultrasound imaging for evaluation of the periodontium in humans. The search was conducted on Medline, EMBASE, Web of Science, Scopus, Cochrane, and PubMed up to April 3, 2023. The studies included were exclusively human studies that assessed the periodontium with ultrasound (US) imaging (b-mode). Outcomes measured included alveolar bone level, alveolar bone thickness, gingival thickness, and blood flow quantification. References were imported to Covidence. Two reviewers conducted phases 1 and 2. The JBI risk assessment tool for cross-sectional studies was used. Extracted data included the transducer and measurements used and the study's outcomes. The search yielded 4892 studies after removing duplicates. From these, 25 studies were included and selected for extraction. Included studies retrieved outcomes from US examinations of the periodontal tissues. From the selected studies, 15 used US on natural teeth, 4 used US on implants, 2 used US on edentulous ridges, and 4 used color flow/power in US to evaluate the blood flow. The results of the present systematic review suggest that US might be a feasible and valuable diagnostic tool for the periodontium, with the potential to complement shortfalls of current radiographic technologies.

The feasibility of ultrasonography for the measurement of periodontal and peri-implant phenotype: A systematic review and meta-analysis

BACKGROUND

Screening ultrasonography was proposed for monitoring periodontal soft tissues in the early 1960s, owing to its nonionizing, real-time, and cost-effective properties. Studies have provided convincing preliminary evidence for the use of ultrasound (US) in implant dentistry.

PURPOSE

To assess the feasibility of ultrasonography (US) for measuring the buccal thickness of periodontal and peri-implant tissues. The secondary objective was to evaluate the reliability of US measurements compared to classic techniques, such as CBCT and directly measurements.

MATERIALS AND METHODS

An electronic literature search was conducted by three independent reviewers through February 2023. The inclusion criteria were articles investigating at least five patients/cadavers with US measurements in periodontal or peri-implant buccal tissues. Compliance with methodological reporting standards and risk of bias was assessed using EULAR and QUADAS-C tools, respectively. Random-effects meta-analysis was conducted, using Bland-Altman analysis. Certainty of the evidence was assessed using GRADE.

RESULTS

The final selection included 12 studies examining 458 patients and 13 cadavers, with a total of 226 implants, 1958 teeth and 60 edentulous sites. The body of evidence was assessed as partially compliant with methodological reporting standards for US studies and had an unclear to high risk of bias. Meta-analysis of five comparative studies showed no evidence of clinically significant bias between US and direct measurements (very low certainty), and between US and CBCT (very low certainty) for soft-tissue thickness. Likewise, for bone thickness, there is no evidence of clinically significant bias between US and CBCT (low certainty).

CONCLUSIONS

Compared to the CBCT and direct measurements, ultrasonography might be a reliable approach for monitoring on periodontal and peri-implant phenotype. However, there is uncertainty about estimates of the actual effect, so further standardized and larger sample size of clinical research is needed.

Diagnostic application of intraoral ultrasonography to assess furcation involvement in mandibular first molars

OBJECTIVES

The objectives were to clarify if intraoral ultrasonography (USG) is: (1) more accurate than conventional periodontal examinations in detection of furcation involvement, and (2) comparable to conventional periodontal examinations in accurate horizontal classification of furcation involvement in comparison to cone beam computed tomography (CBCT).

METHODS

The buccal furcation in 61 lower first molars were evaluated with conventional periodontal examinations, intraoral USG and CBCT. The presence and classification of the horizontal depth of furcation involvement were defined clinically by assessment with a Nabers periodontal probe and a periapical radiograph with reference to the bone loss under the fornix. The horizontal depth of furcation involvement was measured in intraoral USG and CBCT images. Based on the measurements, presence diagnosis and horizontal classification were performed. Results from conventional periodontal examinationsand intraoral USG were compared with those from CBCT.

RESULTS

κ value (κ) for agreement of presence diagnosis of furcation involvement between intraoral USG and CBCT was 0.792, while agreement with conventional periodontal examinations was 0.225. Diagnostic accuracy of intraoral USG exhibited higher values (sensitivity: 98.3%, accuracy: 98.4 %) than conventional periodontal examinations (81.4% and 81.9 %). Weighted κ statistics showed substantial agreement in the classification between intraoral USG and CBCT (κ = 0.674). High agreement (ICC: 0.914) for the measurement of horizontal depth of furcation involvement was found between intraoral USG and CBCT.

CONCLUSIONS

Intraoral USG may be a reliable diagnostic tool for assessment of furcation involvement of mandibular molars with a similar performance to CBCT, but without ionizing radiation.

Overview of Ultrasound in Dentistry for Advancing Research Methodology and Patient Care Quality with Emphasis on Periodontal/Peri-implant Applications

BACKGROUND

Ultrasound is a non-invasive, cross-sectional imaging technique emerging in dentistry. It is an adjunct tool for diagnosing pathologies in the oral cavity that overcomes some limitations of current methodologies, including direct clinical examination, 2D radiographs, and cone beam computerized tomography. Increasing demand for soft tissue imaging has led to continuous improvements on transducer miniaturization and spatial resolution. The aims of this study are (1) to create a comprehensive overview of the current literature of ultrasonic imaging relating to dentistry, and (2) to provide a view onto investigations with immediate, intermediate, and long-term impact in periodontology and implantology.

METHODS

A rapid literature review was performed using two broad searches conducted in the PubMed database, yielding 576 and 757 citations, respectively. A rating was established within a citation software (EndNote) using a 5-star classification. The broad search with 757 citations allowed for high sensitivity whereas the subsequent rating added specificity.

RESULTS

A critical review of the clinical applications of ultrasound in dentistry was provided with a focus on applications in periodontology and implantology. The role of ultrasound as a developing dental diagnostic tool was reviewed. Specific uses such as soft and hard tissue imaging, longitudinal monitoring, as well as anatomic and physiological evaluation were discussed.

CONCLUSIONS

Future efforts should be directed towards the transition of ultrasonography from a research tool to a clinical tool. Moreover, a dedicated effort is needed to introduce ultrasonic imaging to dental education and the dental community to ultimately improve the quality of patient care.

[Measuring methods of volumetric changes of soft tissues at dental implants site and tooth recessions site]

The article is a review of literature on various methods for measuring gingival thickness at implant site and tooth recession. The purpose of the study was to analyze existing methods for assessing volumetric changes in soft tissues based on literature data and give recommendations on the choice of methods. The authors analyzed available methods and identified limitations and recommendations for the use of different methods. The literature review is also helpful to identify promising methods for assessing changes in soft tissue volume, which may help authors of future studies with method selection.

Ultrasound insonation angle and scanning imaging modes for imaging dental implant structures: A benchtop study

INTRODUCTION

High frequency ultrasound has shown as a promising imaging modality to evaluate peri-implant tissues. It is not known if the ultrasound imaging settings might influence ultrasound's ability to differentiate implant structures. The aim of this benchtop study was to evaluate the dependence of ultrasound on imaging angles and modes to measure implant geometry-related parameters.

METHODS

A clinical ultrasound scanner (ZS3, Mindray) with an intraoral probe (L30-8) offering combinations of harmonic and compound imaging modes was employed for imaging 16 abutments and 4 implants. The samples were mounted to a micro-positioning system in a water tank, which allowed a range of -30 to 30-degree imaging angles in 5-degree increment between the probe and samples. The abutment angle, implant thread pitch and depth were measured on ultrasound, compared to the reference readings. The errors were computed as a function of the image angles and modes. All samples were replicated 3 times for 3 image modes and 11 image angles, thus resulting in 2,340 images.

RESULTS

The mean errors of ultrasound to estimate 16 abutment angles, compared to the reference values, were between -1.8 to 2.7 degrees. The root mean squared error (RMSE) ranged from 1.5 to 4.6 degrees. Ultrasound significantly overestimated the thread pitch by 26.1 μm to 36.2 μm. The error in thread depth measurements were in a range of -50.5 μm to 39.6 μm, respectively. The RMSE of thread pitch and depth of the tested 4 implants was in a range of 34.7 to 56.9 μm and 51.0 to 101.8 μm, respectively. In most samples, these errors were independent of the image angle and modes.

CONCLUSIONS

Within the limitations of this study, high-frequency ultrasound was feasible in imaging abutments and implant fixtures independent of scanning angle within ±30° of normal incidence and for compounding and non-compounding-based imaging modes.

High-resolution ultrasonography of gingival biomarkers for periodontal diagnosis in healthy and diseased subjects

OBJECTIVE

To determine the capacity of ultrasonographic image-based measurements of gingival height and alveolar bone level for monitoring periodontal health and disease.

METHODS

Sixteen subjects were recruited from patients scheduled to receive dental care and classified as periodontally healthy (n = 10) or diseased (n = 6) according to clinical guidelines. A 40-MHz ultrasound system was used to measure gingival recession, gingival height, alveolar bone level, and gingival thickness from 66 teeth for comparison to probing measurements of pocket depth and clinical attachment level. Interexaminer variability and comparison between ultrasound measurements and probing measurements was performed via Bland-Altman analysis.

RESULTS

Gingival recession and its risk in non-recessed patients could be determined via measurement of the supra- and subgingival cementoenamel junction relative to the gingival margin. Interexaminer bias for ultrasound image analysis was negligible (<0.10 mm) for imaged gingival height (iGH) and 0.45 mm for imaged alveolar bone level (iABL). Diseased subjects had significantly higher imaging measurements (iGH, iABL) and clinical measurements (probing pocket depth, clinical attachment level) than healthy subjects (p < 0.05). Subtraction of the average biologic width from iGH resulted in 83% agreement (≤1 mm difference) between iGH and probing pocket depth measurements.

CONCLUSIONS

Ultrasonography has an equivalent diagnostic capacity as gold-standard physical probing for periodontal metrics while offering more detailed anatomical information.

Ultrasonographic evaluation of edentulous crestal bone topography: A proof-of-principle retrospective study

OBJECTIVE

Edentulous crestal bone ridge assessment, an essential task for planning of implant and bone regenerative procedures, is performed through radiographs. Ultrasonography, providing point of care and cross-sectional images without radiation, could be an adjunct for this purpose. The aim was to investigate the feasibility of ultrasound (US) in assessing bone ridge width (BRW) and crestal bone surface quality (CBSQ) compared with cone beam computed tomography (CBCT).

STUDY DESIGN

Records of patients who were planned for implant placement in at least 1 healed edentulous ridge space with available CBCT and US images were included. The BRWs at 1, 2, and 3 mm from the crest were measured and compared. The CBSQ agreement evaluated using a 3-tier grading system was calculated.

RESULTS

A total of 45 sites were included. The mean correlation of BRW was 0.97. The mean BRW differences ranged from 0.048 mm (95% confidence interval, -0.69 to 0.78 mm) at the 1-mm level to 0.18 mm (95% confidence interval, -0.92 to 1.3 mm) at the 3-mm level. There was a 91% agreement in CBSQ between the 2 methods.

CONCLUSIONS

Preliminary data with a limited clinical sample size suggested that US is feasible in evaluating crestal BRW and surface quality assessment compared with CBCT.

Ultrasound Imaging in Dentistry: A Literature Overview

(1) Background: the frequency with which diagnostic tests are prescribed with exposure to ionizing radiation, a cause of biological damage, has been studied, and with much more attention, patients are subjected to these diagnostic tests for diagnosis and follow-up. This review aimed, given the recent developments of this technology, to evaluate the possible use of ultrasound in different branches of dentistry. The possibility of applying ionizing-radiation-free diagnostic exams in dentistry, overcoming the limits of this application, has led scientific research in this area to obtain interesting results that bode well for the future. (2) Methods: a search for articles on the application of ultrasounds in dentistry was performed using the PubMed electronic database. (3) Results: only 32 studies were included, and these clearly stated that this examination is widely usable and in great progress. (4) Conclusions: regarding the modern application techniques of this diagnostic test, it is essential to consider technological evolution as an objective to reduce the damage and side effects of necessary diagnostic tests. The use of ultrasound in dentistry can represent a valid radiation-free alternative, in certain contexts, to the other most used exams.

Ultrasonography for noninvasive and real-time evaluation of peri-implant soft and hard tissue: a case series

BACKGROUND

The diagnosis of soft and hard tissue at dental implants will be challenging in the future, as high prevalence of mucositis and peri-implantitis were described in the population. Ultrasonography is a promising non-invasive, inexpensive, painless, and radiation-free method for imaging hard and soft tissue at implants, especially an ultrasound device with a 25-MHz probe demonstrating a high correlation between ultrasound, clinical, and radiological measurements.

CASE PRESENTATION

The following case series demonstrates the use of ultrasonography with high spatial resolution probe in patients with dental implants affected by soft tissue recession and/or crestal bone loss.

CONCLUSION

These ultrasound images can provide valuable additional information for the assessment of peri-implant soft and hard tissue.

Localization of cementoenamel junction in intraoral ultrasonographs with machine learning

OBJECTIVE

Our goal was to automatically identify the cementoenamel junction (CEJ) location in ultrasound images using deep convolution neural networks (CNNs).

METHODS

Three CNNs were evaluated using 1400 images and data augmentation. The training and validation were performed by an experienced nonclinical rater with 1000 and 200 images, respectively. Four clinical raters with different levels of experience with ultrasound tested the networks using the other 200 images. In addition to the comparison of the best approach with each rater, we also employed the simultaneous truth and performance level estimation (STAPLE) algorithm to estimate a ground truth based on all labelings by four clinical raters. The final CEJ location estimate was obtained by taking the first moment of the posterior probability computed using the STAPLE algorithm. The study also computed the machine learning-measured CEJ-alveolar bone crest distance.

RESULTS

Quantitative evaluations of the 200 images showed that the comparison of the best approach with the STAPLE-estimate yielded a mean difference (MD) of 0.26 mm, which is close to the comparison with the most experienced nonclinical rater (MD=0.25 mm) but far better than the comparison with clinical raters (MD=0.27-0.33 mm). The machine learning-measured CEJ-alveolar bone crest distances correlated strongly (R = 0.933, p < 0.001) with the manual clinical labeling and the measurements were in good agreement with the 95% Bland-Altman's lines of agreement between -0.68 and 0.57 mm.

CONCLUSIONS

The study demonstrated the feasible use of machine learning methodology to localize CEJ in ultrasound images with clinically acceptable accuracy and reliability. Likelihood-weighted ground truth by combining multiple labels by the clinical experts compared favorably with the predictions by the best deep CNN approach.

CLINICAL SIGNIFICANCE

Identification of CEJ and its distance from the alveolar bone crest play an important role in the evaluation of periodontal status. Machine learning algorithms can learn from complex features in ultrasound images and have potential to provide a reliable and accurate identification in subsecond. This will greatly assist dental practitioners to provide better point-of-care to patients and enhance the throughput of dental care.

In Vivo Imaging of Biodegradable Implants and Related Tissue Biomarkers

Non-invasive longitudinal imaging of osseointegration of bone implants is essential to ensure a comprehensive, physical and biochemical understanding of the processes related to a successful implant integration and its long-term clinical outcome. This study critically reviews the present imaging techniques that may play a role to assess the initial stability, bone quality and quantity, associated tissue remodelling dependent on implanted material, implantation site (surrounding tissues and placement depth), and biomarkers that may be targeted. An updated list of biodegradable implant materials that have been reported in the literature, from metal, polymer and ceramic categories, is provided with reference to the use of specific imaging modalities (computed tomography, positron emission tomography, ultrasound, photoacoustic and magnetic resonance imaging) suitable for longitudinal and non-invasive imaging in humans. The advantages and disadvantages of the single imaging modality are discussed with a special focus on preclinical imaging for biodegradable implant research. Indeed, the investigation of a new implant commonly requires histological examination, which is invasive and does not allow longitudinal studies, thus requiring a large number of animals for preclinical testing. For this reason, an update of the multimodal and multi-parametric imaging capabilities will be here presented with a specific focus on modern biomaterial research.

PRISMA-S: an extension to the PRISMA statement for reporting literature searches in systematic reviews. J Med Libr Assoc 2021;109:174-200. [PMID: 34285662 PMCID: PMC8270366 DOI: 10.5195/jmla.2021.962]

BACKGROUND

Literature searches underlie the foundations of systematic reviews and related review types. Yet, the literature searching component of systematic reviews and related review types is often poorly reported. Guidance for literature search reporting has been diverse and, in many cases, does not offer enough detail to authors who need more specific information about reporting search methods and information sources in a clear, reproducible way. This document presents the PRISMA-S (Preferred Reporting Items for Systematic reviews and Meta-Analyses literature search extension) checklist, and explanation and elaboration.

METHODS

The checklist was developed using a three-stage Delphi survey process, followed by a consensus conference and public review process.

RESULTS

The final checklist includes sixteen reporting items, each of which is detailed with exemplar reporting and rationale.

CONCLUSIONS

The intent of PRISMA-S is to complement the PRISMA Statement and its extensions by providing a checklist that could be used by interdisciplinary authors, editors, and peer reviewers to verify that each component of a search is completely reported and, therefore, reproducible.

Ultrasonographic tissue perfusion analysis at implant and palatal donor sites following soft tissue augmentation: A clinical pilot study

AIM

To describe the application of power Doppler Ultrasonography (US) for evaluating blood flow at implant and palatal donor sites following soft tissue augmentation with the connective tissue graft (CTG).

MATERIALS AND METHODS

Five patients exhibiting a peri-implant soft tissue dehiscence received treatment with a coronally advanced flap and corresponding CTG. Power Doppler US was used for assessing blood volume at baseline, 1 week, 1 month, 6 months and 12 months post-surgery for assessing blood-flow dynamics at the implant and palatal donor sites. The speed-weighted and power-weighted colour pixel density (CPPD) were computed from colour velocity (CV) and colour power (CP), respectively.

RESULTS

A mean increase in CV of 199.25% was observed at the midfacial region of the implant sites after 1 week compared to baseline. CV and CP were increased in all sites at 1 week and 1 month. At 6 and 12 months, the mean CV appeared lower than baseline at the implant sites. CCPD was increased at the palatal donor sites and at the great palatine foramen areas at the 1-week and 1-month post-operative evaluations.

CONCLUSIONS

Power Doppler US is a non-invasive and valuable tool for estimating tissue perfusion and CPPD variation during different phases of intra-oral soft tissue graft healing.

PRISMA-S: an extension to the PRISMA Statement for Reporting Literature Searches in Systematic Reviews

BACKGROUND

Literature searches underlie the foundations of systematic reviews and related review types. Yet, the literature searching component of systematic reviews and related review types is often poorly reported. Guidance for literature search reporting has been diverse, and, in many cases, does not offer enough detail to authors who need more specific information about reporting search methods and information sources in a clear, reproducible way. This document presents the PRISMA-S (Preferred Reporting Items for Systematic reviews and Meta-Analyses literature search extension) checklist, and explanation and elaboration.

METHODS

The checklist was developed using a 3-stage Delphi survey process, followed by a consensus conference and public review process.

RESULTS

The final checklist includes 16 reporting items, each of which is detailed with exemplar reporting and rationale.

CONCLUSIONS

The intent of PRISMA-S is to complement the PRISMA Statement and its extensions by providing a checklist that could be used by interdisciplinary authors, editors, and peer reviewers to verify that each component of a search is completely reported and therefore reproducible.

Volumetric changes at implant sites: A systematic appraisal of traditional methods and optical scanning-based digital technologies

AIM

To evaluate techniques for assessing soft tissue alterations at implant sites and compare the traditionally utilized methods to the newer three-dimensional technologies emerging in the literature.

MATERIALS AND METHODS

A comprehensive search was performed to identify interventional studies reporting on volumetric changes at implant sites following different treatments.

RESULTS

Seventy-five articles were included the following: 30 used transgingival piercing alone, one utilized calliper, six with ultrasonography, six on cone-beam computed tomography, and 32 utilized optical scanning and digital technologies. Optical scanning-based digital technologies were the only approach that provided 'volumetric changes,' reported as volumetric variation in mm³ , or the mean distance between the surfaces/mean thickness of the reconstructed volume. High variability in the digital analysis and definition of the region of interest was observed. All the other methods reported volume variation as linear dimensional changes at different apico-coronal levels. No studies compared volumetric changes with different approaches.

CONCLUSIONS

Despite the emergence of optical scanning-based digital technologies for evaluating volumetric changes, a high degree of variation exists in the executed workflow, which renders the comparison of study results not feasible. Establishment of universal guidelines could allow for volumetric comparisons among different studies and treatments.

Alveolar Bone Segmentation in Intraoral Ultrasonographs with Machine Learning

The use of intraoral ultrasound imaging has received great attention recently due to the benefits of being a portable and low-cost imaging solution for initial and continuing care that is noninvasive and free of ionizing radiation. Alveolar bone is an important structure in the periodontal apparatus to support the tooth. Accurate assessment of alveolar bone level is essential for periodontal diagnosis. However, interpretation of alveolar bone structure in ultrasound images is a challenge for clinicians. This work is aimed at automatically segmenting alveolar bone and locating the alveolar crest via a machine learning (ML) approach for intraoral ultrasound images. Three convolutional neural network–based ML methods were trained, validated, and tested with 700, 200, and 200 images, respectively. To improve the robustness of the ML algorithms, a data augmentation approach was introduced, where 2100 additional images were synthesized through vertical and horizontal shifting as well as horizontal flipping during the training process. Quantitative evaluations of 200 images, as compared with an expert clinician, showed that the best ML approach yielded an average Dice score of 85.3%, sensitivity of 88.5%, and specificity of 99.8%, and identified the alveolar crest with a mean difference of 0.20 mm and excellent reliability (intraclass correlation coefficient ≥0.98) in less than a second. This work demonstrated the potential use of ML to assist general dentists and specialists in the visualization of alveolar bone in ultrasound images.

Ultrasonography for diagnosis of peri-implant diseases and conditions: a detailed scanning protocol and case demonstration

OBJECTIVES

Ultrasonography has shown its promising diagnostic value in dental implant imaging research in the three treatment phases, namely, planning, intraoperative, and postoperative phase. With increasing awareness of peri-implant diseases and a lack of an efficient diagnostic method, the aim is to propose ultrasound imaging as a potential solution by providing a detailed scanning protocol and case demonstration.

METHODS

Ultrasound device specification and the setup for optimizing peri-implant tissue imaging was described. Two useful imaging modes, viz. B-mode and color flow, were introduced. Important anatomical structures for accurate diagnosis of peri-implant diseases were illustrated. Finally, a detailed scanning sequence was proposed.

RESULTS

Ultrasound images were acquired on live humans to exemplify the four peri-implant diseases and conditions, endorsed by the 2017 World Workshop organized by the American Academy of Periodontology and the European Federation of Periodontology. Ultrasound can provide not only cross-sectional anatomical images but also functional images (color flow images) that may be useful for evaluating the degree of peri-implant tissue inflammation.

CONCLUSIONS

High-frequency ultrasonography could be another cross-sectional imaging modality in adjunct to radiographs for diagnosing imminent peri-implant diseases and conditions that negatively influence quality of life of millions of patients with implants. This case study provides a framework for future related research work and clinical scanning guidelines.

Ultrasonographic characterization of lingual structures pertinent to oral, periodontal, and implant surgery

OBJECTIVES

Increased applications of ridge augmentation in the lingual posterior mandible call for an urgent need to study its anatomy. Therefore, our first aim was to validate ultrasound in measuring the mandibular lingual structures in human cadavers. Secondarily, to test its feasibility in imaging the lingual nerve in live humans.

MATERIALS AND METHODS

Nine fresh un-embalmed fully/partially edentulous cadaver heads were utilized for aim 1. Three areas in the lingual mandible were imaged (mandibular premolar, molar, and retromolar). Immediately after, biopsies were harvested from each site. The thickness of the mucosa, mylohyoid muscle, and lingual nerve diameter was measured via ultrasound and statistically compared to histology. Similarly, the lingual nerve in live humans was also imaged.

RESULTS

None of the differences between the ultrasound and histology measurements reached statistical significance (p > .05). The mean mucosal thickness via ultrasound and histology was 1.45 ± 0.49 and 1.39 ± 0.50 mm, 5 mm lingual to the mylohyoid muscle attachment. At 10 mm beyond the attachment, the ultrasound and histologic values were 1.54 ± 0.48 and 1.37 ± 0.49, respectively. The mean muscle thickness measured via ultrasound and histology was 2.31 ± 0.56 and 2.25 ± 0.47 mm, at the 5 mm distance. At the 10 mm distance, the measurements were 2.46 ± 0.56 and 2.36 ± 0.5 mm, respectively. The mean ultrasonic lingual nerve diameter was 2.38 ± 0.44 mm, versus 2.43 ± 0.42 mm, with histology. The lingual nerve diameter on 19 live humans averaged to 2.01 ± 0.35 mm (1.4-3.1 mm).

CONCLUSIONS

Within its limitations, ultrasound accurately measured mandibular lingual soft tissue structures on cadavers, and the lingual nerve on live humans.

Ultrasonography for chairside evaluation of periodontal structures: A pilot study

BACKGROUND

The crestal bone level and soft tissue dimension are essential for periodontal diagnosis and phenotype determination; yet, existing measurement methods have limitations. The aim of this clinical study was to evaluate the correlation and accuracy of ultrasound in measuring periodontal dimensions, compared to direct clinical and cone-beam computed tomography (CBCT) methods.

METHODS

A 24-MHz ultrasound probe prototype, specifically designed for intraoral use, was employed. Periodontal soft tissue dimensions and crestal bone levels were measured at 40 teeth and 20 single missing tooth gaps from 20 patients scheduled to receive a dental implant surgery. The ultrasound images were interpreted by two calibrated examiners. Inter-rater agreement was calculated by using inter-rater correlation coefficient (ICC). Ultrasound readings were compared with direct clinical and CBCT readings by using ICC and Bland-Altman analysis.

RESULTS

The following six parameters were measured: 1) interdental papilla height (tooth), 2) mid-facial soft tissue height (tooth), 3) mucosal thickness (tooth), 4) soft tissue height (edentulous ridge), 5) mucosal thickness (edentulous ridge), and 6) crestal bone level (tooth). Intra-examiner calibrations were exercised to achieve an agreement of at least 0.8. ICC between the two readers ranged from 0.482 to 0.881. ICC between ultrasound and direct readings ranged from 0.667 to 0.957. The mean difference in mucosal thickness (tooth) between the ultrasound and direct readings was -0.015 mm (95% CI: -0.655 to 0.624 mm) without statistical significance. ICC between ultrasound and CBCT ranged from 0.654 to 0.849 among the measured parameters. The mean differences between ultrasound and CBCT range from -0.213 to 0.455 mm, without statistical significance.

CONCLUSION

Ultrasonic imaging can be valuable for accurate and real-time periodontal diagnosis without concerns about ionizing radiation.