Feasibility of a combination of intraoral UHFUS and CBCT in the study of peri-implantitis

Ultrasound-based jawbone surface quality evaluation after alveolar ridge preservation

BACKGROUND

Bone readiness for implant placement is typically evaluated by bone quality/density on 2-dimensional radiographs and cone beam computed tomography at an arbitrary time between 3 and 6 months after tooth extraction and alveolar ridge preservation (ARP). The aim of this study is to investigate if high-frequency ultrasound (US) can classify bone readiness in humans, using micro-CT as a reference standard to obtain bone mineral density (BMD) and bone volume fraction (BVTV) of healed sockets receiving ARP in humans.

METHODS

A total of 27 bone cores were harvested during the implant surgery from 24 patients who received prior extraction with ARP. US images were taken immediately before the implant surgery at a site co-registered with the tissue biopsy collection location, made possible with a specially designed guide, and then classified into 3 tiers using B-mode image criteria (1) favorable, (2) questionable, and (3) unfavorable. Bone mineral density (hydroxyapatite) and BVTV were obtained from micro-CT as the gold standard.

RESULTS

Hydroxyapatite and BVTV were evaluated within the projected US slice plane and thresholded to favorable (>2200 mg/cm3; >0.45 mm3/mm3), questionable (1500-2200 mg/cm3; 0.4-0.45 mm3/mm3), and unfavorable (<1500 mg/cm3; <0.4 mm3/mm3). The present US B-mode classification inversely scales with BMD. Regression analysis showed a significant relation between US classification and BMD as well as BVTV. T-test analysis demonstrated a significant correlation between US reader scores and the gold standard. When comparing Tier 1 with the combination of Tier 2 and 3, US achieved a significant group differentiation relative to mean BMD (p = 0.004, true positive 66.7%, false positive 0%, true negative 100%, false negative 33.3%, specificity 100%, sensitivity 66.7%, receiver operating characteristics area under the curve 0.86). Similar results were found between US-derived tiers and BVTV.

CONCLUSION

Preliminary data suggest US could classify jawbone surface quality that correlates with BMD/BVTV and serve as the basis for future development of US-based socket healing evaluation after ARP.

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.

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.

Ultra-High-Frequency Ultrasound: A Modern Diagnostic Technique for Studying Melanoma

The development of new ultra-high-frequency devices with a resolution of 30 μm makes it possible to use ultrasound in the study of new small anatomical units and to apply this tool to new fields of pathology. Cutaneous melanoma is a severe skin disease with an incidence of approximately 160 000 new cases each year and 48 000 deaths. In this paper, we evaluate the role of HFUS in the diagnosis of cutaneous melanoma, describe the sonographic appearance of skin layers in the pre-excision phase as well as of lesion features, and correlate the characteristics with pathological examination.

Noninvasive Digital Method for Determining Inflammation after Dental Implantation

This study shows that the luminescent diagnostic of oral fluid allows the determination of the severity of inflammatory markers after implantation. The noninvasive diagnostic method, which is used, allows the rapid detection of the stages of development of the inflammatory process after intraosseous implantation and prevents the development of complications in the postoperative period.

Clinical Application of Ultra-High-Frequency Ultrasound

Musculoskeletal ultrasound involves the study of many superficial targets, especially in the hands, wrists, and feet. Many of these areas are within the first 3 cm of the skin surface and are ideal targets for ultra-high-frequency ultrasound. The high spatial resolution and the superb image quality achievable allow foreseeing a wider use of this novel technique, which has the potential to bring innovation to diagnostic imaging.

Clinical application of ultra-high frequency ultrasound: Discovering a new imaging frontier

The ultra-high frequency ultrasound (UHFUS) is characterized by the use of probes between 30 and 100 MHz. This technology has recently been introduced in clinical practice and represents an opportunity for the diagnosis of numerous pathologies. The high spatial resolution of UHFUS, up to 30 μ in pixel size, allows to study the pathological modifications and to guide microsurgery treatments in anatomical body structures not evaluable by conventional HFUS. The aim of this work is to provide a review of the literature on the current clinical applications of UHFUS and to discuss its added role in different clinical settings.

Evaluating the Relationship between Mandibular Third Molar and Mandibular Canal with Semiautomatic Segmentation: A Pilot Study on CBCT Datasets

Inferior alveolar nerve injury is the main complication in mandibular third molar surgery. In this context, cone-beam computed tomography (CBCT) has become of crucial importance in evaluating the relationship between mandibular third molar and inferior alveolar nerve. Due to the growing interest in preoperative planning in oral surgery, several post-processing techniques have been implemented to obtain three-dimensional reconstructions of a volume of interest. In the present study, segmentation techniques were retrospectively applied to CBCT images in order to evaluate whether post-processing could offer better visualization of the structures of interest. Forty CBCT examinations performed for inferior third molar impaction were analyzed. Segmentation and volumetric reconstructions were performed. A dataset composed of multiplanar reconstructions for each study case, including segmented images, was submitted for evaluation to two oral surgeons, two general practitioners and four residents in oral surgery. The visualization of root morphology, canal course, and the relationship with mandibular cortical bone on both native CBCT and segmented images were assessed. Inter-rater agreement showed values of intraclass correlation coefficient (ICC) above 0.8 for all the examined parameters. Oral surgeons presented higher ICC values (p < 0.05). Segmented images can improve preoperative evaluation of the third molar and its relationship with the surrounding anatomical structures compared to native CBCT images. Further evaluation is needed to validate these preliminary results.

Using Cone-Beam Computed Tomography to Assess Changes in Alveolar Bone Width around Dental Implants at Native and Reconstructed Bone Sites: A Retrospective Cohort Study

The aim of this study was to use a cone-beam computed tomography (CBCT) to assess changes in alveolar bone width around dental implants at native and reconstructed bone sites before and after implant surgery. A total of 99 implant sites from 54 patients with at least two CBCT scans before and after implant surgery during 2010–2019 were assessed in this study. Demographic data, dental treatments and CBCT scans were collected. Horizontal alveolar bone widths around implants at three levels (subcrestal width 1 mm (CW1), subcrestal width 4 mm (CW4), and subcrestal width 7 mm (CW7)) were measured. A p-value of < 0.05 indicated statistically significant differences. The initial bone widths (mean ± standard deviation (SD)) at CW1, CW4, and CW7 were 6.98 ± 2.24, 9.97 ± 2.64, and 11.33 ± 3.00 mm, respectively, and the postsurgery widths were 6.83 ± 2.02, 9.58 ± 2.55, and 11.19 ± 2.90 mm, respectively. The change in bone width was 0.15 ± 1.74 mm at CW1, 0.39 ± 1.12 mm at CW4 (p = 0.0008), and 0.14 ± 1.05 mm at CW7. A statistically significant change in bone width was observed at only the CW4 level. Compared with those at the native bone sites, the changes in bone width around implants at reconstructed sites did not differ significantly. A significant alveolar bone width resorption was found only at the middle third on CBCT scans. No significant changes in bone width around implants were detected between native and reconstructed bone sites.

Evaluation of Depth of Invasion in Oral Squamous Cell Carcinoma with Ultra-High Frequency Ultrasound: A Preliminary Study

Intraoral ultrasonography has been widely employed for the preoperative assessment of tumor margins due to its capability to evaluate depth of invasion (DOI) and tumor thickness (TT). Recently, a novel ultrasonographic technique, ultra-high frequency ultrasound (UHFUS) has been increasingly applied to the study of oral lesions. This study evaluates the potential application of intraoral UHFUS to assess DOI and TT parameters of oral squamous cell carcinoma (OSCC) lesions. Patients clinically suspected of OSCC lesions were enrolled and underwent an intraoral UHFUS examination preoperatively. The parameters of TT, DOI, echogenicity, and vascularization were assessed. The parameters of TT and DOI as evaluated by means of UHFUS were compared to histology, which was set as the benchmark. Ten patients in total were enrolled. UHFUS-based DOI and TT measurements were found to positively correlate with histology (p < 0.05), although UHFUS provided a slight overestimation of DOI. No differences were found in terms of echogenicity or vascularization depending on the site of the lesion. According to these preliminary results, UHFUS could support the preoperative assessment of TT and DOI, potentially enhancing the clinical evaluation of OSCC.

Ultra-high frequency ultrasonography (UHFUS)-guided minor salivary gland biopsy: A promising procedure to optimize labial salivary gland biopsy in Sjögren's syndrome

BACKGROUND

Sjögren's syndrome (SS) is an autoimmune disease characterized by an inflammatory infiltrate of exocrine salivary and lachrymal glands. Diagnosis is complex, and minor salivary gland biopsy and subsequent focus score (FS) calculation appear of extreme importance in the diagnostic work-up of the disease. Ultra-high frequency ultrasonography (UHFUS) is a recently introduced diagnostic technique, which is gaining an increasingly important role in intraoral imaging. This study aims at exploring the usefulness of UHFUS for obtaining valuable labial salivary gland samples to assess the histopathological features of SS patients.

METHODS

Patients with clinical suspect of SS and eligible for minor salivary gland biopsy were enrolled. UHFUS scan of the lower lip was performed. Glandular echostructure was classified according to Outcome Measures in Rheumatology (OMERACT) scoring system. The glands to be sampled were selected on the basis of UHFUS evaluation and biopsied. The areas of the samples were recorded and compared with those obtained without UHFUS guidance. The correlation between UHFUS grade and labial gland FS was also assessed.

RESULTS

The areas of the samples obtained with UHFUS guidance were significantly higher (7.25 ± 3.98 mm² ) than those obtained by conventional procedures (5.79 ± 3.49 mm² , P = .02). UHFUS correlated significantly with the salivary gland FS (r = .532, P = .001).

CONCLUSION

UHFUS seems a promising tool in SS diagnostic algorithm, being able to provide a valuable support to the biopsy procedure. Further studies are mandatory to confirm the role of UHFUS in SS.

Ultra-high frequency ultrasound in the differential diagnosis of oral pemphigus and pemphigoid: An explorative study

OBJECTIVES

Intraoral ultra-high frequency ultrasound (UHFUS) is an emerging technique in oral medicine, due to its possibility to provide submillimeter resolution imaging of superficial mucosal structures. In this study, the potential role of UHFUS in the diagnosis of oral pemphigus vulgaris (PV) and mucous membrane pemphigoid (MMP) is assessed.

MATERIALS AND METHODS

Consecutive patients with suspected oral PV or MMP were enrolled. All patients underwent clinical examination, laboratory tests, intraoral UHFUS scan, and biopsy. Histology and direct immunofluorescence were set as benchmark for diagnosis confirmation. The sensitivity and specificity of UHFUS compared to histology were assessed. Mann-Whitney test was performed to evaluate the presence of differences in the echogenicity of PV and MMP. P-value was set at P < 0.05.

RESULTS

Twenty-five patients were included. Thirteen patients were diagnosed with PV, and twelve with MMP. The UHFUS features of PV and MMP lesions were described. Image analysis showed statistically significant differences between the echogenicity of PV and MMP lesions (P < 0.05). Good concordance between UHFUS and histology was found. UHFUS showed 75% sensitivity in the diagnosis of PV and 66.7% in the diagnosis of MMP.

CONCLUSIONS

UHFUS appears a valuable tool in the diagnosis of PV and MMP. Although histology and immunofluorescence remain the gold standard, UHFUS role in the diagnostic algorithm of PV and MMP seems promising as a chair-side tool consistently enhancing clinical evaluation of oral bullous lesions.

Ultra-high frequency ultrasound (UHFUS) applications in Sjogren syndrome: narrative review and current concepts

Primary Sjogren's syndrome (SS) is a systemic autoimmune chronic inflammatory disease with predominant involvement of the exocrine glands, particularly the salivary glands (SGs). The role of salivary glands ultrasound (SGUS) in the work-up of patients with primary Sjogren syndrome (SS) is progressively increasing due to its useful support in diagnosis and follow-up as a widely available, repeatable, non-invasive and safe technique. Although SGUS is not yet included in the dominant primary SS classification, several studies supported its inclusion in the American College of Rheumatology/European League Against Rheumatism criteria. In this context, a novel imaging technique, ultra-high frequency ultrasound (UHFUS), is being explored. Compared to the frequencies used in conventional ultrasound (US) (up to 22 MHz), UHFUS operates with higher frequencies (30-100 MHz) allowing for outstanding image resolution, up to 30 µm. UHFUS permits the scan of both major and minor SGs, opening new avenues for the integration of tissue and imaging biomarkers. Although further studies are needed to confirm its role, this novel imaging technique might lead to several potential improvements, including earlier diagnosis, reduction of unnecessary and inadequate biopsies and better management and follow-up of patients with primary SS.

Ultra-High Frequency Ultrasound, A Promising Diagnostic Technique: Review of the Literature and Single-Center Experience

OBJECTIVES

Ultra-high frequency ultrasonography (UHFUS) is a recently introduced diagnostic technique which finds several applications in diverse clinical fields. The range of frequencies between 30 and 100 MHz allows for high spatial resolution imaging of superficial structures, making this technique suitable for the imaging of skin, blood vessels, musculoskeletal anatomy, oral mucosa, and small parts. However, the current clinical applications of UHFUS have never been analyzed in a consistent multidisciplinary manner. The aim of this study is to revise and discuss the current applications of UHFUS in different aspects of research and clinical practice, as well as to provide some examples of the current work-in-progress carried out in our center.

MATERIALS AND METHODS

A literature search was performed in order to retrieve articles reporting the applications of UHFUS both in research and in clinical settings. Inclusion criteria were the use of frequencies above 30 MHz and study design conducted in vivo on human subjects.

RESULTS

In total 66 articles were retrieved. The majority of the articles focused on dermatological and vascular applications, although musculoskeletal and intraoral applications are emerging fields of use. We also describe our experience in the use of UHFUS as a valuable diagnostic support in the fields of dermatology, rheumatology, oral medicine, and musculoskeletal anatomy.

CONCLUSION

Ultra-high frequency ultrasonography application involves an increasing number of medical fields. The high spatial resolution and the superb image quality achievable allow to foresee a wider use of this novel technique, which has the potential to bring innovation in diagnostic imaging.

Discovering a new anatomy: exploration of oral mucosa with ultra-high frequency ultrasound

OBJECTIVES

Ultra-high frequency ultrasound (UHFUS) is a recently developed diagnostic technique involving the use of ultrasound frequencies up to 70 MHz, allowing to obtain 30 µm resolution of targets located within 1 cm from the surface. Oral mucosa can be affected by diverse pathological conditions, which are currently investigated by means of clinical examination. In this scenario, intraoral UHFUS can provide additional information and support clinical assessment of oral mucosa. In this preliminary study, typical features of normal oral mucosa are described, in order to set a benchmark for the future identification of oral soft tissue alterations.

METHODS

Twenty healthy subjects (10 males and 10 females, mean age 30 years) were enrolled and underwent intraoral UHFUS examination. In all the subjects, tongue, buccal mucosa, gingiva, lip mucosa, and palate were scanned, and images acquired. Intraoral UHFUS scan included Brightness-mode and Doppler mode acquisitions performed with a standardized protocol. UHFUS images were postprocessed and analyzed using a dedicated software. UHFUS-based biomarkers (epithelial thickness, echogenicity, and vascularization) were employed for image description.

RESULTS

Normal oral anatomy of the different sites analyzed was described. For all the sites, UHFUS biomarkers were characterized, and information on typical aspect of oral mucosa was retrieved.

CONCLUSIONS

In this explorative study, we suggest a potential role for intraoral UHFUS in the study of oral mucosa, giving insights into the possibility to improve the assessment, diagnosis, and management of the conditions involving oral mucosa. UHFUS seems a promising tool, which could potentially support clinical examination in daily oral medicine practice.

The efficacy of Ultra-High Frequency Ultrasonography in the diagnosis of intraoral lesions

OBJECTIVES

The aim of the present study was to evaluate the diagnostic efficacy of ultra-high frequency ultrasound (UHFUS) imaging of intraoral soft tissue lesions.

STUDY DESIGN

The study included 160 patients presenting with oral soft tissue lesions classified into 4 categories: autoimmune diseases, mucosal growths, potentially (pre)malignant lesions, and oral cancer. Each lesion was evaluated by means of intraoral UHFUS, through B-mode and C-mode acquisitions of the area of interest. The UHFUS findings were compared with the histopathologic findings.

RESULTS

All values for sensitivity, specificity, and negative predictive value exceeded 90%. Sensitivity was perfect (100%) for mucosal growths and oral cancer. Specificity was almost perfect for all 4 categories of lesions, ranging from 97% to 99%. Values for positive predictive value ranged from 83% to 99%.

CONCLUSIONS

UHFUS was beneficial in imaging the oral mucosa and the superficial aspects of the underlying soft tissue in detail because of the high spatial resolution of the technique. Consistent patterns were recognized for different categories of lesions. UHFUS holds the promise of being a valuable support to the clinician in terms of diagnosis, treatment, and follow-up of oral lesions.

Intraoral Ultra-High Frequency Ultrasound study of oral lichen planus: A pictorial review

BACKGROUND

Ultra-High Frequency Ultrasound (UHFUS) is a recently introduced diagnostic technique involving the use of higher frequencies compared to conventional ultrasound. Among the several fields of application, intraoral usage of UHFUS appears still limited. We report the intraoral evaluation of Oral Lichen Planus (OLP) by means of UHFUS and describe typical UHFUS aspect of different forms of presentation of OLP.

MATERIALS AND METHODS

Patients with clinical and histological diagnosis of OLP were enrolled in the study. OLP lesions were evaluated by means of intraoral UHFUS performed at 70 MHz, using B-mode and C-mode, in order to characterize the echostructure of each form of presentation.

RESULTS

Fifty patients in total were enrolled, and UHFUS features were described for different OLP forms. All the lesions showed a thick, hypoechoic superficial layer in the mucosal stratum, suggesting that such UHFUS alteration can be pathognomonic of OLP.

CONCLUSION

Ultra-High Frequency Ultrasound was able to differentiate superficial alterations of the oral mucosa, giving insight on possible applications of UHFUS in the study of OLP beyond clinical and histological investigations. Due to a limited study sample, we cannot draw firm conclusions. However, it is reasonable to think that UHFUS evaluation of OLP may provide useful information to the clinician.