Cervical soft tissue imaging using a mobile CBCT scanner with a flat panel detector in comparison with corresponding CT and MRI data sets

OBJECTIVE: The aim of this study was to evaluate soft tissue image quality of a mobile cone-beam computed tomography (CBCT) scanner with an integrated flat-panel detector. STUDY DESIGN: Eight fresh human cadavers were used in this study. For evaluation of soft tissue visualization, CBCT data sets and corresponding computed tomography (CT) and magnetic resonance imaging (MRI) data sets were acquired. Evaluation was performed with the help of 10 defined cervical anatomical structures. RESULTS: The statistical analysis of the scoring results of 3 examiners revealed the CBCT images to be of inferior quality regarding the visualization of most of the predefined structures. Visualization without a significant difference was found regarding the demarcation of the vertebral bodies and the pyramidal cartilages, the arteriosclerosis of the carotids (compared with CT), and the laryngeal skeleton (compared with MRI). Regarding arteriosclerosis of the carotids compared with MRI, CBCT proved to be superior. CONCLUSIONS: The integration of a flat-panel detector improves soft tissue visualization using a mobile CBCT scanner.

Loss of pulp sensitivity and pain as the first symptoms of a Ewing's sarcoma in the right maxillary sinus and alveolar process: report of a case

This case report describes the diagnosis and treatment of a Ewing's sarcoma in the right maxillary sinus and alveolar bone of a 19-year-old female patient. The first clinical symptoms were a loss of sensitivity of the premolars and first molar in the right maxilla and acute pain located in the area of these teeth. Initially, the referring dentist had treated these findings as an acute apical periodontitis with root canal medication. Because swellings on the palatal and buccal aspects of the teeth occurred and could not be treated with incision and drainage, the dentist referred the patient. Cone-beam computed tomography revealed a proliferation of soft tissue in the right maxillary sinus, with a radiopaque material at the tip of the mesiobuccal root of the first molar and resorptive signs of the mesiobuccal and distobuccal roots of the first molar. The palatal cortical bone of the right alveolar process seemed to be intact. After explorative surgery with biopsies from the buccal, palatal, and sinus proliferation areas, the pathologist diagnosed the lesion as a Ewing's sarcoma. Treatment of the patient consisted of initial chemotherapy, hemimaxillectomy, and postsurgical chemoradiotherapy.

Anterior Stafne's bone cavity mimicking a periapical lesion of endodontic origin: report of two cases

INTRODUCTION: This report of 2 cases describes the diagnostic procedures used to identify 2 Stafne's bone cavities (SBC) found in unusually anterior locations in the mandible, both mimicking periapical lesions of endodontic origin. METHODS: In the first patient, a 47-year-old man, an SBC was diagnosed in the area of teeth #27, 28, and 29. In the second patient, a 62-year-old man, the SBC was a fortuitous finding, because this patient was referred for dental implant therapy. RESULTS: In both cases, the final diagnosis was achieved by using limited cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI). In both patients, the lingual bone cavity was found to be occupied by accessory salivary gland tissue. CONCLUSIONS: The combination of CBCT and MRI as noninvasive diagnostic techniques seems ideal to avoid surgical explorations, incisional biopsies, or enucleations of the lesion for diagnostic purposes.

Long-term stability of early implant placement with contour augmentation

In this prospective case series study, 20 patients with an implant-borne single crown following early implant placement with simultaneous contour augmentation were followed for 6 years. Clinical, radiologic, and esthetic parameters were assessed. In addition, cone beam computed tomography (CBCT) was used at 6 years to examine the facial bone wall. During the study period, all 20 implants were successfully integrated, and the clinical parameters remained stable over time. Pleasing esthetic outcomes were noted, as assessed by the pink esthetic scores. None of the implants developed mucosal recession of 1 mm or more. The periapical radiographs yielded stable peri-implant bone levels, with a mean DIB of 0.44 mm at 6 years. The CBCT scans showed that all 20 implants had a detectable facial bone wall at 6 years, with a mean thickness of around 1.9 mm. In summary, this prospective case series study demonstrated stable peri-implant hard and soft tissues for all 20 implants, and pleasing esthetic outcomes overall. The follow-up of 6 years confirmed that the risk for mucosal recession is low with early implant placement. In addition, contour augmentation with guided bone regeneration (GBR) was able to establish and maintain a facial bone wall in all 20 patients.

Anatomical characteristics and dimensions of edentulous sites in the posterior maxillae of patients referred for implant therapy

The purpose of this study was to analyze the width and height of edentulous sites in the posterior maxilla using cone beam computed tomography (CBCT) images from patients referred for implant therapy. A total of 122 CBCT scans were included in the analysis, resulting in a sample size of 252 edentulous sites. The orofacial crest width was measured in coronal slices, perpendicular to the alveolar ridge. The bone height was analyzed in the respective sagittal slices. Additionally, the following secondary outcome parameters were evaluated: the morphology of the sinus floor, the presence of septa in the maxillary sinus, and the thickness of the sinus membrane. The mean crest width for all analyzed sites was 8.28 mm, and the mean bone height was 7.22 mm. The percentage of patients with a crest width of less than 6 mm was 27% in premolar sites and 7.8% in molar sites. The bone height decreased from premolar to molar areas, with a high percentage of first and second molar sites exhibiting a bone height of less than 5 mm (54.12% and 44.64%, respectively). Regarding the morphology of the sinus floor, 53% of the edentulous sites exhibited a flat configuration. A septum was present in 67 edentulous sites (26.59%). Analysis of the sinus membrane revealed 88 sites (34.9%) with increased mucosal thickness (> 2 mm). For the crest width, the location of the edentulous site and the morphology of the sinus floor were both statistically significant variables. For the crest width and mean bone height, the location of the edentulous site and the morphology of the sinus floor were both statistically significant variables. The study confirmed that a high percentage of edentulous sites in the posterior maxilla do require sinus floor elevation to allow the placement of dental implants. Therefore, a detailed three-dimensional radiograph using CBCT is indicated in most patients for proper treatment planning.

[The mental foramen or "the crossroads of the mandible." An anatomic and clinical observation]

This paper presents a clinical and anatomical review of the mental foramen (MF) based on recent publications (since 1990). Usually, the MF is located below the 2nd premolar or between the two premolars, but it may also be positioned below the 1st premolar or below the mesial root of the 1st molar. At the level of the MF, lingual canals may join the mandibular canal (hence the term "crossroads"). Accessory MF are frequently described in the literature with large ethnic variations in incidence. The emergence pattern of the mental canal usually has an upward and posterior direction. The presence and extent of an "anterior loop" of the mental canal may be overestimated with panoramic radiography. Limited cone-beam computed tomography currently appears to be the most precise radiographic technique for assessment of the "anterior loop". The mental nerve exiting the MF usually has three to four branches for innervation of the soft tissues of the chin, lower lip, facial gingiva and mucosa in the anterior mandible. The clinician is advised to observe a safety distance when performing incisions and osteotomies in the vicinity of the MF.

A bone-thickness map as a guide for bone-anchored port implantation surgery in the temporal bone

The bone-anchored port (BAP) is an investigational implant, which is intended to be fixed on the temporal bone and provide vascular access. There are a number of implants taking advantage of the stability and available room in the temporal bone. These devices range from implantable hearing aids to percutaneous ports. During temporal bone surgery, injuring critical anatomical structures must be avoided. Several methods for computer-assisted temporal bone surgery are reported, which typically add an additional procedure for the patient. We propose a surgical guide in the form of a bone-thickness map displaying anatomical landmarks that can be used for planning of the surgery, and for the intra-operative decision of the implant’s location. The retro-auricular region of the temporal and parietal bone was marked on cone-beam computed tomography scans and tridimensional surfaces displaying the bone thickness were created from this space. We compared this method using a thickness map (n = 10) with conventional surgery without assistance (n = 5) in isolated human anatomical whole head specimens. The use of the thickness map reduced the rate of Dura Mater exposition from 100% to 20% and OPEN ACCESS Materials 2013, 6 5292 suppressed sigmoid sinus exposures. The study shows that a bone-thickness map can be used as a low-complexity method to improve patient’s safety during BAP surgery in the temporal bone.

Complication sévère d’une contention collée linguale mandibulaire

Le collage d’un fil torsadé souple sur les faces linguales des six dents antérieures mandibulaires est une modalité de contention couramment utilisée. Les complications sont rares mais peuvent être assez sérieuses pour provoquer des dégâts biologiques. Cet article présente une complication sérieuse d’un fil de contention torsadé souple, collé en lingual. Quatre ans après son traitement orthodontique, un homme de 20 ans a consulté pour la rupture d’un fil de contention torsadé souple. L’examen clinique a montré un torque radiculo-vestibulaire d’environ 35° d’une dent. Une image en tomographie volumique à faisceau conique (Cone-Beam Computed Tomography ou CBCT) a montré que la racine et l’apex de la dent étaient presque totalement hors de l’os du côté vestibulaire. Étonnamment, la vitalité de la dent était préservée. La dent a été ramenée presque jusqu’à sa position initiale; cliniquement, seule une récession gingivale a persisté. Les orthodontistes et les dentistes devraient être conscients des complications possibles des contentions collées. Les patients devraient être clairement informés de la manière dont les problèmes peuvent être détectés à un stade précoce.

Localization of impacted maxillary canines and root resorption of neighbouring teeth: a study assessing the diagnostic value of panoramic radiographs in two groups of observers.

OBJECTIVES To assess the diagnostic value of panoramic views (2D) of patients with impacted maxillary canines by a group of trained orthodontists and oral surgeons, and to quantify the subjective need and reasons for further three-dimensional (3D) imaging. MATERIALS AND METHODS The study comprises 60 patients with panoramic radiographs (2D) and cone beam computed tomography (CBCT) scans (3D), and a total of 72 impacted canines. Data from a standardized questionnaire were compared within (intragroup) and between (intergroup) a group of orthodontists and oral surgeons to assess possible correlations and differences. Furthermore, the questionnaire data were compared with the findings from the CBCT scans to estimate the correlation within and between the two specialties. Finally, the need and reasons for further 3D imaging was analysed for both groups. RESULTS When comparing questionnaire data with the analysis of the respective CBCT scans, orthodontists showed probability (Pr) values ranging from 0.443 to 0.943. Oral surgeons exhibited Pr values from 0.191 to 0.946. Statistically significant differences were found for the labiopalatal location of the impacted maxillary canine (P = 0.04), indicating a higher correlation in the orthodontist group. The most frequent reason mentioned for the further need of 3D analysis was the labiopalatal location of the impacted canines. Oral surgeons were more in favour of performing further 3D imaging (P = 0.04). CONCLUSIONS Orthodontists were more likely to diagnose the exact labiopalatal position of impacted maxillary canines when using panoramic views only. Generally, oral surgeons more often indicated the need for further 3D imaging.

Long-term stability of contour augmentation in the esthetic zone: histologic and histomorphometric evaluation of 12 human biopsies 14 to 80 months after augmentation.

BACKGROUND Contour augmentation around early-placed implants (Type 2 placement) using autogenous bone chips combined with deproteinized bovine bone mineral (DBBM) and a collagen barrier membrane has been documented to predictably provide esthetically satisfactory clinical outcomes. In addition, recent data from cone beam computed tomography studies have shown the augmented volume to be stable long-term. However, no human histologic data are available to document the tissue reactions to this bone augmentation procedure. METHODS Over an 8-year period, 12 biopsies were harvested 14 to 80 months after implant placement with simultaneous contour augmentation in 10 patients. The biopsies were subjected to histologic and histomorphometric analysis. RESULTS The biopsies consisted of 32.0% ± 9.6% DBBM particles and 40.6% ± 14.6% mature bone. 70.3% ± 14.5% of the DBBM particle surfaces were covered with bone. On the remaining surface, multinucleated giant cells with varying intensity of tartrate-resistant acid phosphatase staining were regularly present. No signs of inflammation were visible, and no tendency toward a decreasing volume fraction of DBBM over time was observed. CONCLUSIONS The present study confirms previous findings that osseointegrated DBBM particles do not tend to undergo substitution over time. This low substitution rate may be the reason behind the clinically and radiographically documented long-term stability of contour augmentation using a combination of autogenous bone chips, DBBM particles, and a collagen membrane.

Neurovascular disturbances after implant surgery

With a steadily increasing impact of oral implant placement in daily practice, the number of reported surgical complications has also been growing. Recent studies reveal significant variation in the occurrence and morphology of neurovascular canal structures in the jaw bone. All those structures contain a neurovascular bundle, the diameter of which may be large enough to cause clinically significant damage. Therefore, it has become obvious that presurgical radiographic planning of jaw-bone surgery should pay attention to the neurovascular structures and their likely variations, in addition to examining many other factors, such as jaw-bone morphology and volume, bone trabecular structure and the absence of bone or tooth pathology. A critical review is accomplished to explore the potential risks for neurovascular complications after implant placement, with evidence derived from histologic, anatomic, clinical and radiologic studies. In this respect, cross-sectional imaging can often be advocated, as it is obvious that the inherent three-dimensional nature of jaw-bone anatomy may clearly benefit from a detailed spatial image analysis. Although this could initially be realized by conventional computed tomography, in current practice, dentomaxillofacial cone beam computed tomography might be used, as it offers high-quality images at low radiation dose levels and costs.

Soft Tissue Alterations in Esthetic Postextraction Sites: A 3-Dimensional Analysis.

Dimensional alterations of the facial soft and bone tissues following tooth extraction in the esthetic zone play an essential role to achieve successful outcomes in implant therapy. This prospective study is the first to investigate the interplay between the soft tissue dimensions and the underlying bone anatomy during an 8-wk healing period. The analysis is based on sequential 3-dimensional digital surface model superimpositions of the soft and bone tissues using digital impressions and cone beam computed tomography during an 8-wk healing period. Soft tissue thickness in thin and thick bone phenotypes at extraction was similar, averaging 0.7 mm and 0.8 mm, respectively. Interestingly, thin bone phenotypes revealed a 7-fold increase in soft tissue thickness after an 8-wk healing period, whereas in thick bone phenotypes, the soft tissue dimensions remained unchanged. The observed spontaneous soft tissue thickening in thin bone phenotypes resulted in a vertical soft tissue loss of only 1.6 mm, which concealed the underlying vertical bone resorption of 7.5 mm. Because of spontaneous soft tissue thickening, no significant differences were detected in the total tissue loss between thin and thick bone phenotypes at 2, 4, 6, and 8 wk. More than 51% of these dimensional alterations occurred within 2 wk of healing. Even though the observed spontaneous soft tissue thickening in thin bone phenotypes following tooth extraction conceals the pronounced underlying bone resorption pattern by masking the true bone deficiency, spontaneous soft tissue thickening offers advantages for subsequent bone regeneration and implant therapies in sites with high esthetic demand (Clinicaltrials.gov NCT02403700).

Real-Time In Vivo Characterization of Primary Liver Tumors With Diffuse Optical Spectroscopy During Percutaneous Needle Interventions: Feasibility Study in Woodchucks

OBJECTIVE This study presents the first in vivo real-time optical tissue characterization during image-guided percutaneous intervention using near-infrared diffuse optical spectroscopy sensing at the tip of a needle. The goal of this study was to indicate transition boundaries from healthy tissue to tumors, namely, hepatic carcinoma, based on the real-time feedback derived from the optical measurements. MATERIALS AND METHODS Five woodchucks with hepatic carcinoma were used for this study. The woodchucks were imaged with contrast-enhanced cone beam computed tomography with a flat panel detector C-arm system to visualize the carcinoma in the liver. In each animal, 3 insertions were performed, starting from the skin surface toward the hepatic carcinoma under image guidance. In 2 woodchucks, each end point of the insertion was confirmed with pathologic examination of a biopsy sample. While advancing the needle in the animals under image guidance such as fluoroscopy overlaid with cone beam computed tomography slice and ultrasound, optical spectra were acquired at the distal end of the needles. Optical tissue characterization was determined by translating the acquired optical spectra into clinical parameters such as blood, water, lipid, and bile fractions; tissue oxygenation levels; and scattering amplitude related to tissue density. The Kruskal-Wallis test was used to study the difference in the derived clinical parameters from the measurements performed within the healthy tissue and the hepatic carcinoma. Kurtoses were calculated to assess the dispersion of these parameters within the healthy and carcinoma tissues. RESULTS Blood and lipid volume fractions as well as tissue oxygenation and reduced scattering amplitude showed to be significantly different between the healthy part of the liver and the hepatic carcinoma (P < 0.05) being higher in normal liver tissue. A decrease in blood and lipid volume fractions and tissue oxygenation as well as an increase in scattering amplitude were observed when the tip of the needle crossed the margin from the healthy liver tissue to the carcinoma. The kurtosis for each derived clinical parameter was high in the hepatic tumor as compared with that in the healthy liver indicating intracarcinoma variability. CONCLUSIONS Tissue blood content, oxygenation level, lipid content, and tissue density all showed significant differences when the needle tip was guided from the healthy tissue to the carcinoma and can therefore be used to identify tissue boundaries during percutaneous image-guided interventions.

Evaluation of the maxillary sinus in panoramic radiography—a comparative study

Background: The aim of this study was to evaluate the validity and the inter- and intra-examiner reliability of panoramic-radiograph-driven findings of different maxillary sinus anatomic variations and pathologies, which had initially been prediagnosed by cone beam computed tomography (CBCT). Methods: After pairs of two-dimensional (2D) panoramic and three-dimensional (3D) CBCT images of patients having received treatment at the outpatient department had been screened, the predefinition of 54 selected maxillary sinus conditions was initially performed on CBCT images by two blinded consultants individually using a questionnaire that defined ten different clinically relevant findings. Using the identic questionnaire, these consultants performed the evaluation of the panoramic radiographs at a later time point. The results were analyzed for inter-imaging differences in the evaluation of the maxillary sinus between 2D and 3D imaging methods. Additionally, two resident groups (first year and last year of training) performed two diagnostic runs of the panoramic radiographs and results were analyzed for inter- and intra-observer reliability. Results: There is a moderate risk for false diagnosis of findings of the maxillary sinus if only panoramic radiography is used. Based on the ten predefined conditions, solely maxillary bone cysts penetrating into the sinus were frequently detected differently comparing 2D to 3D diagnostics. Additionally, on panoramic radiographs, the inter-observer comparison demonstrated that basal septa were significantly often rated differently and the intra-observer comparison showed a significant lack in reliability in detecting maxillary bone cysts penetrating into the sinus. Conclusions: Panoramic radiography provides the most information on the maxillary sinus, and it may be an adequate imaging method. However, particular findings of the maxillary sinus in panoramic imaging may be based on a rather examiner-dependent assessment. Therefore, a persistent and precise evaluation of specific conditions of the maxillary sinus may only be possible using CBCT because it provides additional information compared to panoramic radiography. This might be relevant for consecutive surgical procedures; consequently, we recommend CBCT if a precise preoperative evaluation is mandatory. However, higher radiation dose and costs of 3D imaging need to be considered. Keywords: Panoramic radiography; Cone beam computed tomography; Maxillary sinus; Inter-imaging method differences; Inter-examiner reliability; Intra-examiner reliability

The virtual patient in dental medicine

OBJECTIVES The aim of this Short Communication was to present a workflow for the superimposition of intraoral scan (IOS), cone-beam computed tomography (CBCT), and extraoral face scan (EOS) creating a 3D virtual dental patient. MATERIAL AND METHODS As a proof-of-principle, full arch IOS, preoperative CBCT, and mimic EOS were taken and superimposed to a unique 3D data pool. The connecting link between the different files was to detect existing teeth as constant landmarks in all three data sets. RESULTS This novel application technique successfully demonstrated the feasibility of building a craniofacial virtual model by image fusion of IOS, CBCT, and EOS under 3D static conditions. CONCLUSIONS The presented application is the first approach that realized the fusion of intraoral and facial surfaces combined with skeletal anatomy imaging. This novel 3D superimposition technique allowed the simulation of treatment planning, the exploration of the patients' expectations, and the implementation as an effective communication tool. The next step will be the development of a real-time 4D virtual patient in motion.