Xie-Qi Shi

• Professor
• Professor at University of Bergen

Objectives The aim of this study was to investigate whether a low‐dose cone‐beam computed tomography (CBCT) protocol provides diagnostically acceptable image quality for assessing bone healing after alveolar bone grafting. Material and Methods The study cohort comprised 11 patients (aged 7–14 years) with orofacial clefts who had undergone alveolar...

Objective: To elucidate cone-beam computed tomography (CBCT) referral profiles in Western Norway. Materials and methods: In all, 3,031 referrals to oral- and maxillofacial radiologist were reviewed. Patient data were retrieved retrospectively from electronic charts. The patient’s age, gender, and perceived clinical indication were noted, as well as...

Automated tooth segmentation and identification on dental radiographs are crucial steps in establishing digital dental workflows. While deep learning networks have been developed for these tasks, their performance has been inferior in partially edentulous individuals. This study proposes a novel semi-supervised Transformer-based framework (SemiTNet...

Background Osteoporosis is increasingly being recognized in children, mostly secondary to systemic underlying conditions or medication. However, no imaging modality currently provides a full evaluation of bone health in children. We compared DXA, a radiographic bone health index (BHI (BoneXpert) and cone-beam CT for the assessment of low bone mass...

Objectives To determine pre-operative cleft volume and evaluate cleft´s impact on surrounding anatomical structures in children and adolescents with orofacial clefts using cone bean computed tomography (CBCT) imaging. Methods The present retrospective study retrieved CBCT examinations of 68 patients from a previous study. The examinations had been...

Background Knowledge on oral health-related quality of life (OHRQoL) in children and adolescents with juvenile idiopathic arthritis (JIA) is limited, and longitudinal studies are lacking. We aimed to describe OHRQoL in children and adolescents with JIA compared to controls, and to explore the validity and internal consistency of the Early Childhood...

Objectives: We aimed to map the correlation between thermoluminescent dosimeters (TLDs) and Gafchromic film for measuring absorbed doses and to compare minimum, maximum, and mean absorbed doses over larger regions of interest and at various craniofacial organs and tissues during cone beam computed tomography (CBCT) exposure of the mandibular third...

Background: Children born with an alveolar cleft receive bone grafts for improved function and aesthetics. The cleft area is radiologically examined before and post bone graft. Optimizing x-ray examination protocols is essential to protect these patients from possible delayed radiation injury later in life. This study investigates whether image qu...

Snoring is a common condition in the general population, and the management of snoring requires a better understanding of its mechanism through a fluid-structure interaction (FSI) perspective. Despite the recent popularity of numerical FSI techniques, outstanding challenges are accurately predicting airway deformation and its vibration during snori...

Objective: Optimization of radiographic examinations is essential for radiation protection. The objective of the study was to investigate the clinical applicability of a low-dose CBCT protocol as compared to the default for pre-surgical evaluation of mandibular third molars. Material & methods: Forty-eight patients (62 teeth) referred for pre-su...

The uvula flapping is one of the most distinctive features of snoring and is critical in affecting airway aerodynamics and vibrations. This study aimed to elucidate the mechanism of pharyngeal vibration and pressure fluctuation due to uvula flapping employing fluid–structure interaction simulations. The followings are the methodology part: we const...

Background The temporomandibular joint (TMJ) is frequently involved in juvenile idiopathic arthritis (JIA). Diagnostic imaging is necessary to correctly diagnose and evaluate TMJ involvement, however, hitherto little has been published on the accuracy of the applied scoring systems and measurements. The present study aims to investigate the precisi...

Computational fluid dynamics (CFD) has the potential for use as a clinical tool to predict the aerodynamics and respiratory function in the upper airway (UA) of children; however, careful selection of validated computational models is necessary. This study constructed a 3D model of the pediatric UA based on cone beam computed tomography (CBCT) imag...

Background Preterm birth has been shown to cause various long-term health issues. Children who were born preterm have also been observed to have more dental behaviour management problems (DBMP) during dental examinations and treatment than children born full term. It is known that dental radiographic examinations can be uncomfortable and cause anxi...

Background Few studies have investigated oral health-related quality of life (OHRQoL) in young individuals with juvenile idiopathic arthritis ( JIA). Aims were to investigate whether OHRQoL differs between children and adolescents with JIA compared to controls without JIA, while adjusting for socio-demographic-, behavioral- and oral health-related...

Objective : To investigate how cone beam computed tomography (CBCT) affects the therapeutic planning of impacted maxillary canines. Study Design : A total of 132 impacted canines from 89 pediatric patients were collected from three specialist clinics in Stockholm, Sweden. An interdisciplinary therapy-planning team consisting of five dental special...

Objective: To explore whether plaque and gingival bleeding are more frequently experienced by adolescents with juvenile idiopathic arthritis (JIA) compared to matched controls without JIA; explore whether surface- and site-specific periodontal outcomes vary between the two groups; and for participants with JIA, investigate associations between dis...

Objectives To examine the precision of imaging measures commonly used to assess mandibular morphology in children and adolescents with juvenile idiopathic arthritis (JIA). Secondly, to compare cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) in the measurement of condylar height. Methods Those included were children diagno...

Background: Preterm birth has been shown to cause various long-term health issues. Children who were born preterm have also been observed to have more behaviour management problems (BMP) during dental examinations and treatment than children born full term. It is known that dental radiographic examinations can be uncomfortable and cause anxiety in...

Objectives To query the experience of oral surgeons concerning referral routines and preferences for radiographic imaging modality before surgical removal of mandibular third molars and investigate factors that influence imaging modality preferences. Materials and methods Members of the Swedish Association of Oral and Maxillofacial Surgeons ( n =...

Background Children and adolescents with juvenile idiopathic arthritis (JIA) may suffer from temporomandibular disorder (TMD). Due to this, imaging diagnosis is crucial in JIA with non-symptomatic TM joint (TMJ) involvement. The aim of the study was to examine the association between clinical TMD signs/symptoms and cone-beam computed tomography (CB...

Objectives To evaluate overall image quality and visibility of anatomic structures on low-dose cone beam computed tomography (CBCT) scans and the effect of a noise reduction filter for assessment of the anterior maxilla. Methods We obtained 48 CBCT volumes on eight skull-phantoms using six protocols: two clinical default protocols [standard defini...

Background Optimal utilization of dental caries data is crucial in epidemiological research of individuals with juvenile idiopathic arthritis (JIA). The aims were to: explore whether caries is more prevalent among children and adolescents with JIA compared to controls; examine presence of caries according to JIA group, socio-behavioral and intraora...

Background Adenoid hypertrophy among orthodontic patients may be detected in lateral cephalograms. The study investigates the aerodynamic characteristics within the upper airway (UA) by means of computational fluid dynamics (CFD) simulation. Furthermore, airflow features are compared between subgroups according to the adenoidal nasopharyngeal (AN)...

Objectives: This retrospective observational study aimed to evaluate the diagnostic accuracy of two-dimensional radiographs on canine-induced root resorption (CIRR) in lateral incisors and identify predictors of CIRR in patients with impacted maxillary canines (IMC). Methods: Ninety-nine patients aged 9-17 years, with 156 IMCs, were included in...

Objectives The present study evaluated the effect of rapid maxillary expansion (RME) on the morphology of the upper airway (UA) by calculating cross-sectional areas and volumes and comparing the effect in patients with a normal-sized adenoid with the effect in patients with an enlarged adenoid. Study design: Seventeen patients met the inclusion cri...

Background: The lateral cephalogram is a common imaging diagnostic test for adenoid hypertrophy (AH) in clinics. The study aims to investigate the aerodynamic characteristics within the upper airway (UA) by employing a computational fluid dynamics (CFD) simulation. Furthermore, airflow features are compared between subgroups according to the adenoi...

Objectives This study aimed to identify potential clinical and radiological predictors associated with the outcome of discectomies. Methods In this retrospective observational study, the material comprised preoperative CBCT images and medical records of 62 patients with disc derangement disorders, who had undergone discectomy because of disc displ...

The aim of the study was to estimate and to compare effective doses in the elbow region resulting from four different x‐ray imaging modalities. Absorbed organ doses were measured using 11 metal oxide field effect transistor (MOSFET) dosimeters that were placed in a custom‐made anthropomorphic elbow RANDO phantom. Examinations were performed using S...

Background The effect of rapid maxillary expansion (RME) on the upper airway (UA) has been studied earlier but without a consistent conclusion. This study aims to evaluate the outcome of RME on the UA function in terms of aerodynamic characteristics by applying a computational fluid dynamics (CFD) simulation. Methods This retrospective cohort stud...

Objectives The aim was to evaluate the characteristics of the mandibular third molars, especially in relation to the inferior alveolar nerve. Further aims were to investigate incidental findings in panoramic radiographs in an adult population, and to investigate image quality related to patient positioning. Materials and Methods From a previous stu...

Background: The effect of rapid maxillary expansion (RME) on the upper airway (UA) has been studied earlier but without a consistent conclusion. This study aims to evaluate the outcome of RME on the upper airway function in terms of airflow resistance by applying a computational fluid dynamics (CFD) simulation. Methods: This retrospective cohort st...

International Association for the Study of Pain (IASP) world congress on pain in Amsterdam 2020. This year a virtual poster.

Abstract Background Children and adolescents with juvenile idiopathic arthritis (JIA) may suffer pain from temporomandibular disorder (TMD). Still, routines for the assessment of temporomandibular joint (TMJ) pain in health and dental care are lacking. The aims of this study were to examine the prevalence of TMD in children and adolescents with JIA...

Objectives To develop and evaluate an educational web‐based program for temporomandibular joint (TMJ) assessment using cone‐beam computed tomography (CBCT). Methods A web‐based educational program was designed for TMJ assessment using CBCT images. Fifteen CBCT cases of the TMJ (three‐dimensional reconstructed volumes) and an assessment module base...

Background. Children and adolescents with JIA may suffer pain from temporomandibular disorder (TMD) and routines for the assessment of temporomandibular joint (TMJ) pain for the health and dental care are lacking. The aims were to examine the prevalence of TMD in children and adolescents with juvenile idiopathic arthritis (JIA) as compared to their...

Background. Children and adolescents with juvenile idiopathic arthritis (JIA) may suffer pain from temporomandibular disorder (TMD). Still, routines for the assessment of temporomandibular joint (TMJ) pain in health and dental care are lacking. The aims of this study were to examine the prevalence of TMD in children and adolescents with JIA compare...

Objective Evaluation of cone-beam computed tomography (CBCT) examination with a low-dose scanning protocol for assessment of the temporomandibular joint (TMJ). Methods 34 adult patients referred for CBCT imaging of the TMJ underwent two examinations with two scanning protocols, a manufacturer-recommended protocol (default) and a low-dose protocol...

Cone-beam computed tomography (CBCT) examination of the tem-poromandibular joint (TMJ) has become a recognised tool in case of suspicion for the presence of osseous changes, after a thorough history and clinical examination of the patient. CBCT images provide high spatial resolution in three-dimensional (3D) images, which is desirable in diagnostic...

Background: Observational studies examining the association between oral health and juvenile idiopathic arthritis (JIA) among children and adolescents have reported inconsistent findings. The aims of this systematic review and meta-analysis were to ascertain a potential difference in oral health and oral health-related quality of life (OHRQoL) amo...

Objectives: The aims of this study were to evaluate the subjective image quality and reliability of two digital sensors. In addition, the image quality of the two sensors evaluated by specialists and general dentists were compared. Methods: Thirty intraoral bitewings from five patients were included in the study, 15 were exposed with a Dixi sens...

Objectives The aim of this study was to evaluate the reliability of bitewing and panoramic radiographs in marginal bone level measurements in terms of inter- and intra-observer agreement. Methods Fifty paired bitewing and panoramic images were used. Eight observers measured marginal bone level at the mesial and distal surfaces of tooth 25 and toot...

Background: Autologous grafting, despite some disadvantages, is still considered the gold standard for reconstruction of maxillofacial bone defects. The aim of this study was to evaluate bone regeneration using bone marrow-derived mesenchymal stromal cells (MSCs) in a clinical trial, a less invasive approach than autologous bone grafting. This com...

Objectives: The primary aim was to evaluate the effective dose for a full size panoramic image and nine different panoramic protocols using collimation. The secondary aim was to estimate possible reduction of effective dose in clinical situations. Methods: Effective dose, according to International Commission on Radiological Protection (ICRP) 20...

Objectives: To compare the radiation dose to children examined for impacted canines, using two-dimensional examinations (panoramic and periapical radiographs) and cone-beam computed tomography (CBCT). Methods: Organ doses were determined using an anthropomorphic 10-year child phantom. Two CBCT devices, a ProMax3D and a NewTom5G, were examined us...

Purpose: To evaluate the ultra-low dose scanning protocols of a newly developed CBCT for pre-implant radiographic assessment. Materials and methods: A total number of 32 CBCT scans were exposed at 90 kV using ProMax 3D's standard (GS) and three ultra-low dose scanning protocols: high, mid and low definition (UL-HD, UL-MD and UL-LD) on eight huma...

The objective of the present study was to assess and compare the effective doses in the wrist region resulting from conventional radiography device, multislice computed tomography (MSCT) device and two cone beam computed tomography (CBCT) devices using MOSFET dosemeters and a custom made anthropomorphic RANDO phantom according to the ICRP 103 recom...

Background Nerve injury may induce neuropathic pain. In studying the mechanisms of orofacial neuropathic pain, attention has been paid to the plastic changes that occur in the trigeminal ganglia (TGs) and nucleus in response to an injury of the trigeminal nerve branches. Previous studies have explored the impact of sciatic nerve injury on dorsal ro...

Objectives: The objectives of this study were to present the subjective knowledge level and the use of image processing on digital intraoral radiographs amongst general dental practitioners at Distriktståndvrden AB, Stockholm. Material and methods: A questionnaire, consisting of12 questions, was sent to 12 dental prac- tices in Stockholm. Additi...

To compare the effective dose to patients from temporomandibular joint examinations using a dental cone-beam CT device and a multi-slice CT device, both before and after dose optimization. A Promax3D (Planmeca, Helsinki, Finland) dental cone-beam CT and a Lightspeed VCT (GE, Fairfield, USA) multi-slice CT were used. Organ doses and effective doses...

The aim of this study was to assess and compare the effective doses (ICRP 103) in the ankle region of X-ray imaging resulting from a multi slice computed tomography (MSCT) device, two cone beam CT (CBCT) devices and one conventional x-ray device. Organ dose measurements were performed using 20 metal oxide field effect transistor (MOSFET) dosimeters...

In this study, we aimed to evaluate the adenoidal nasopharyngeal ratio (ANR) on lateral cephalograms by assessing upper airway volumes using cone-beam computed tomography (CBCT) images as the validation method. Fifty-five patients were included in the study, and it was essential that the lateral cephalograms and CBCT images taken at their examinati...

To assess the impact of spatial resolution and CBCT unit on cone beam computed tomography (CBCT) images for the detection accuracy of condylar defects. Forty-two temporomandibular joints (TMJs) were scanned respectively with the CBCT units Promax 3D and DCT Pro at normal and high resolutions. Seven dentists evaluated all the test images with respec...

The psychophysical properties of a new complementary metal oxide semi-conductor-based detector, ProSensor® (Planmeca Oy, Helsinki, Finland), in terms of dose response function and perceptibility curve test were performed and compared with those of a charged couple device-based sensor, Dixi® (Planmeca Oy). Dose response functions at 66 kVp for a Dix...

The objective was to investigate diagnostic performance on approximal caries detection among Swedish and Chinese dental students using analogue and digital radiographs in vitro. Additionally, to compare the diagnostic accuracy of two image modalities for approximal caries detection. 46 extracted premolars and molars were mounted in blocks and expos...

Effective dose assessment of NewTom5G in different dentalprotocols

Objectives: To investigate and compare the detection accuracy of bony defects on the condylar surface of the temporomandibular joint (TMJ) in cone beam CT (CBCT) images scanned with standard and large view protocols on the same machine. Methods: 21 dry human skulls with 42 TMJs were scanned with the large view and standard view protocols of the...

The aim of this study was to evaluate the performance of the automatic exposure control (AEC) in an intraoral digital system. Three series of radiographs were captured with the activated AEC on seven dry mandibles adhered to different thicknesses of Plexiglas((R)), which represented soft tissue. Exposure times required for each radiograph of the sp...

The objective of this study was to compare detection of approximal caries in vitro by black-and-white and color-coded digital radiographs. The material comprised 2 groups of tooth sample. One group consisted of 40 premolars mounted in groups of 3 or 4 and the other group included 90 premolars mounted in groups of 5. Radiographs, respectively expose...

A new generation of the laser fluorescence device, DIAGNOdent, for caries detection and quantification has been introduced recently. It is the DIAGNOdent pen. The aim of this study was to compare the validity and reliability of both laser-based devices, DIAGNOdent and the DIAGNOdent pen, in quantifying smooth surface caries. The material comprised...

The aims of this study were to evaluate the effect of two caries-preventive programs, and to apply the laser fluorescence method, DIAGNOdent, for longitudinal quantification of changes in incipient carious lesions. Twelve subjects with 127 test teeth exhibiting white spot lesions on the buccal surfaces after completed orthodontic therapy were enrol...

The aim of this study was to evaluate the reliability of a laser-induced infrared fluorescence method, DIAGNOdent, for measuring orthodontically induced white spot lesions. The subjects comprised 13 orthodontic patients, aged 13-17 years, who had recently completed fixed appliance therapy: 137 test teeth were selected, with white spot lesions on th...

It is hypothesized that occlusal lesions are initiated on the fissure walls and can therefore be obscured by sound superficial tissue. Additionally, there is evidence that one effect of regular use of fluorides is greater opacity of enamel, which may obscure underlying lesions in dentin, the so-called 'hidden lesions'. Dental radiographs are inadeq...

The diagnostic value of DIAGNOdent in detecting primary occlusal caries has been investigated in many studies, although its use in in vivo detection of secondary caries remains unclear. The aim of this study was to investigate the ability of DIAGNOdent in in vivo detection of secondary caries on teeth with amalgam restorations. The material compris...

The aims of this in vitro study were 2-fold: 1) to evaluate two fluorescence methods (DIAGNOdent and QLF (quantitative light-induced fluorescence)) for quantification of white spot lesions adjacent to fixed orthodontic appliances; and 2) to determine the inter-observer agreement of the DIAGNOdent and QLF methods for quantification of incipient enam...

A colour scale has been developed as a complement to the grey scale in radiographs. The aim of the present study was to compare colour-coded with conventional black-and-white radiographs in terms of the perceptibility curve test. Twelve digital radiographs were exposed on a test object from low to high exposures and recorded using the DIXI system (...

Objective To determine technical properties for a direct digital intraoral radiographic system, F1iOX (Fimet Oy, Moninkylä, Finland). Methods A dose response function was calculated from seven radiographs exposed to a homogenous radiation field. The line spread function (LSF) and the modulation transfer function (MTF) were determined from a radiogr...

Objectives To construct and analyze perceptibility curves (PCs) according to two different approaches. Material and methods A test object was used to determine the exposures and exposure differences between the total thickness of the test object and details consisting of holes of increasing depth. Two digital systems were employed to predict PCs ac...

To compare psychophysical properties of two intraoral films and three digital systems using the perceptibility curve (PC) test. A test object was used to determine the exposures and exposure differences between the total thickness of the test object and details consisting of holes of increasing depth. The PCs for the two intraoral films, UltraSpeed...

DIAGNOdent is now well documented for detection of primary occlusal caries, but not as yet for secondary caries. The aim of this study was to investigate the application of DIAGNOdent for in vitro detection of secondary caries. The material comprised 66 extracted teeth: 48 with amalgam restorations and 18 with tooth-colored restorations. Digital im...

Two digital image processing methods, correction for X-ray attenuation and correction for attenuation and visual response, have been developed. The aim of the present study was to compare digital radiographs before and after correction for attenuation and correction for attenuation and visual response by means of a perceptibility curve test. Radiog...

To construct perceptibility curves (PCs) for given calibration settings in order to define psychophysical properties of the Digora storage phosphor system and to evaluate the effects of automatic exposure correction (AEC) on the PCs. The Digora system was calibrated at two exposures, 80 microC kg(-1) (high calibration) and 40 microC kg(-1) (low cal...

The Electronic Caries Monitor (ECM) and the recently introduced laser-based KaVo DIAGNOdent have been developed as clinical diagnostic aids in the detection and quantification of occlusal carious lesions. The aim of this in vitro study was to compare their reproducibility and validity. The ability of DIAGNOdent to retrieve sites of occlusal carious...

A color scale was designed with an approach that combined both human visual response to color and physical properties of color. The design was initiated with a subjective evaluation of a 16 step color scale running from dark blue via magenta, orange to light yellow. The CIELUV chromaticity diagram was employed to verify the subjectively generated s...

To evaluate if digital compensation for exponential attenuation and the characteristics of the human visual system improves the diagnosis of approximal caries from digital radiographs. Forty premolar teeth were mounted in plaster blocks. Radiographs of the teeth were exposed with the Dixi digital intraoral system employing a Prostyle Intra dental X...

In vivo repeatability and reproducibility of the quantitative light-induced fluorescence (QLF) method were tested with respect to three variables: lesion area, and average and maximum changes in lesion fluorescence. To test the image-capturing stages, three analysts each captured images of 15 incipient smooth surface lesions in vivo, and the images...

The aims of this study were to investigate the anti-inflammatory effect and the effect on bone regeneration of hyaluronan in surgical and non-surgical groups. In each of 15 individuals, 2 teeth with defects of similar character and magnitude in the upper or lower jaw were chosen. There were at least 2 teeth between the test and the control sites. I...

To construct Perceptibility Curves (PCs) for contrast-enhanced digital intraoral radiographs. Radiographs of a test object having holes of increasing depths were exposed using three digital systems, the CDR (Schick Technologies, Long Island, NY, USA), the Dixel (J Morita MFG, Kyoto, Japan) and the Sens-A-Ray (Regam Medical Systems, Sundsvall, Swede...

The aims were 1) to validate a laser-based device, KaVo DIAGNOdent, for quantification of caries lesions on smooth surfaces, using histopathologic and microradiographic analyses as the gold standard, and 2) to test inter- and intra-observer agreements. We also investigated the influence on DIAGNOdent readings of the storage medium used for extracte...

Eruption patterns and root growth were visualized with the use of a new technique, radiographic color-coding, for comparison of the development of autotransplanted premolars with contralateral control teeth. Rates of eruption and root growth were studied. The eruption pattern and rate was assessed relative to the first molar. Maximum rates were fou...

To evaluate the use of tuned-aperture computed tomography (TACT) for the detection of primary occlusal caries. The material comprised 76 extracted posterior teeth, 51 with caries. Radiographs were recorded both with the Sens-A-Ray (Regam Medical Systems Int. AB, Sundsvall, Sweden) digital radiographic system and with Kodak EktaSpeed Plus film (East...

The aim was to compare the detection and quantification of smooth surface caries by KaVo DIAGNOdent and quantitative laser/light-induced fluorescence (QLF) using a laser and a lamp as two different light sources. On 40 premolar teeth extracted from adolescents, 71 non-cavitated approximal surfaces were assessed. For QLF, both mean and maximum fluor...

A new laser fluorescence method, KaVo DIAGNOdent, was tested with respect to reproducibility and validity and compared with radiography regarding accuracy in the detection of occlusal caries. Seventy-six extracted premolar and molar teeth were measured twice with DIAGNOdent under both wet and dry conditions, at an interval of 2 weeks. Conventional...

A new method for detection and quantification of natural incipient caries lesions, the Quantitative Light-induced Fluorescence method (QLF), has recently been developed. The aim of this study was to test the repeatability and reproducibility of the analytical part of the method. In vivo captured images (CCD-video camera, Panasonic WV-KS 152, with a...