Kristina Hellén-Halme

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• Professor
• Professor at Malmö University

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...

This study evaluated radiographic graft changes following maxillary sinus floor augmentation with (A) autogenous bone, (B) 1:1 autogenous bone and deproteinized porcine bone mineral, or (C) 1:1 autogenous bone and biphasic bone graft material. Sixty patients were randomly allocated to groups A, B, and C (20 in each). CBCT scans were obtained at enr...

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...

Objectives: To evaluate the cephalometric effects of premolar extraction on skeletal and dental parameters, and on the soft tissues, in patients subsequently treated with fixed appliances. Prevalence and severity of external apical root resorption due to premolar extraction were also examined. Materials and methods: The dental records of 79 pati...

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...

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...

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 and Objectives: There is limited information regarding comparison of long-term dynamics of periapical bone destruction estimated by digital periapical radiography (DPR) and by cone-beam computed tomography (CBCT). This study aimed to compare the radiographically assessed periapical changes of endodontically treated teeth over 2 years of...

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 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)...

Background Endodontic treatment planning and treatment success evaluation are largely based on radiographic assessment of anatomical and treatment-related parameters of teeth with apical periodontitis (AP). This prospective clinical study aimed to assess radiographically the 2-year endodontic treatment outcomes for teeth with AP, and to evaluate pr...

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 aim of this study was to investigate whether a complementary Cone-Beam Computed Tomography (CBCT) in patients with Cleft Lip and Palate (CLP) after alveolar bone-grafting to clefts gave substantial additional information, and particularly whether such new information had any implications for the further care of the patients. Methods...

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...

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...

Purpose: The aim of this study was to assess the artefacts of 12 fixed orthodontic appliances in magnetic resonance images obtained using 1.5-T and 3-T scanners, and to evaluate different imaging sequences designed to suppress metal artefacts. Materials and methods: In vitro, study casts of 1 adult with normal occlusion were used. Twelve orthodo...

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...

Background: To evaluate whether buccal bone thickness (BBT), implant diameter, and abutment/crown material influence the accuracy of cone beam computed tomography (CBCT) to determine the buccal bone level at titanium implants. Methods: Two implant beds (i.e., narrow and standard diameter) were prepared in each of 36 porcine bone blocks. The impl...

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...

Objectives: To compare selected anatomical and treatment-related diagnostic parameters estimated by cone-beam computed tomography and by digital periapical radiography in teeth with apical periodontitis, and to evaluate reliability of different examiners in interpretation of images obtained by both methods. Material and Methods: Teeth with apical...

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...

Objectives: The aim of this study was to map and compare the distributions of absorbed doses with Gafchromic film for panoramic radiography and cone beam computed tomography (CBCT) examinations of the temporomandibular joint (TMJ) by using adult and child phantoms. Study design: Gafchromic films were placed at 5 selected levels of anthropomorphi...

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...

Objectives: This retrospective study investigated requests and indications for cone-beam computed tomography (CBCT) in children and adolescents over a 3-year period at one oral and maxillofacial radiology department. Specific aims were to determine what technical settings were used, which caregivers write the referrals, and how often and for what r...

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...

Objectives: Osseous changes in temporomandibular joint disorders (TMD) are common indications for cone beam computed tomography (CBCT). The number of such cases is increasing while number of qualified oral radiologists is limited. The present study investigated usefulness of a training program for general dental practitioners (GDPs) regarding temp...

Background There is rising concern about how preterm birth affects long-term health later in life. The various effects that preterm birth have on developmental outcomes, cognitive profiles and medical health may also affect levels of cooperation in the dental care situation in addition to general oral health and other oral health-related habits. Or...

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...

Objective: This study investigated the diagnostic accuracy of digital dental radiography for detecting carious lesions on approximal surfaces before and after optimization of the environ - ment, and after joint training on evaluation and review of x-rays. A further aim was to evaluate differences in diagnostic accuracy between general dental prac...

Objectives: Radiographic images suffer from varying amounts of noise. The most studied and discussed of these is random noise. However, recent research has shown that projected anatomy contributes substantially to noise, especially when detecting low-contrast objects in the images. Our aim, therefore, was to evaluate the extent to which over-proje...

Objectives: Cone-beam computed tomography in dentistry can be used in some countries by other dentists than specialists in radiology. The frequency of buying cone-beam computed tomography to examine patients is rapidly growing, thus knowledge of how to use it is very important. The aim was to compare the outcome of an investigation on the use of c...

Abstract: CBCT Constancy Controls: How user friendly is the new Phantom? A pilot study (Oral Surg Oral Med Oral Pathol Oral Radiol. 2014 Nov; 118(5):603-11) Introduction and objectives A new inexpensive phantom for image quality control (IQA) on maxillofacial Cone Beam CT (CBCT) was presented in a recent paper. All important structures for the IQA...

Objectives: Cone beam computed tomography (CBCT) was introduced to Norwegian dental clinics in 2007. The aim of the study was to investigate how dental clinics use this imaging modality, including factors related to workflow and image quality, and to evaluate dentists' opinions on and experiences of using it. Materials and methods: A web-based 5...

The purpose of this work was to develop an inexpensive phantom for simplified image quality assurance (IQA) together with algorithms for objective evaluation of image quality parameters and to integrate these components into an easy-to-use software package. This should help make quality control of dental cone beam computed tomography (CBCT) units a...

The aim of this study was to evaluate the image quality of digital panoramic radiographs and its correlation with the detectability of normal anatomical structures. The effects of image enhancement on the detectability were also studied. A total of 500 panoramic images (DICOM format) obtained with a storage phosphor-based digital system were evalua...

Efforts are made in radiographic examinations to obtain the best image quality with the lowest possible absorbed dose to the patient. In dental radiography, the absorbed dose to patients is very low, but exposures are relatively frequent. It has been suggested that frequent low-dose exposures can pose a risk for development of future cancer. It has...

Objectives: This study investigated the effect of different monitor calibration modes under various ambient lighting conditions on the ability of observers to recognize proximal carious lesions of varying depths. Methods: 7 observers evaluated 100 teeth for proximal carious lesions on standardized digital radiographs using 3 set-ups: (1) pre-cal...

Objectives: Research diagnostic criteria for temporomandibular disorders (RDC/TMDs) were proposed in 1992 with the aim of standardizing and testing methods for diagnosing TMDs. RDC/TMDs have so far been lacking standardized methods for imaging and criteria for imaging diagnosis of disorders of the temporomandibular joint (TMJ). Criteria for disord...

This study investigated how ambient light affects the diagnostic accuracy of dental carious lesions on monitors used in dental practice. Specifically, the aim was to evaluate whether a monitor hood for blocking excess ambient light increases practitioners' ability to accurately diagnose carious lesions on digital radiographs under bright ambient li...

The aim of this study was to evaluate the luminance level of monitors as a function of the burning time of the lamp in the monitor and further to evaluate if different areas of the monitor varied in luminance levels at a specific time. Nine standard liquid crystal display (LCD) monitor models, in total 180 monitors, were evaluated. The monitors' ma...

This study evaluated the effect of two different tube voltages on clinicians' ability to diagnose approximal carious lesions in digital radiographs. One hundred extracted teeth were radiographed twice at two voltage settings, 60 and 70 kV, using a standardized procedure. Seven observers evaluated the radiographs on a standard color monitor pre-cali...

This study evaluated whether variations in education level and experience among dental staff influence the diagnostic accuracy of carious lesions on digital radiographs. Three student groups and a fourth group of general practitioners (Dentists) with more than five years of clinical experience participated in this study.The student groups were (i)...

The aim of this study was to evaluate if different ways of adjusting brightness and contrast of monitors with different technical standards influence the diagnosis of carious lesions in digital radiographs. One hundred extracted teeth (premolars and molars) were radiographed. Seven observers evaluated images for approximal carious lesions on 3 moni...

The aim of this study was to investigate how brightness and contrast settings of the display monitor and ambient light level (illuminance) in the viewing room affect the clinician's ability to diagnose carious lesions in digital radiographs. Standardized radiographs were taken of 100 extracted teeth. Seven observers evaluated the images for approxi...

The aim of this study was to conduct a field study to survey the performance of digital radiography and how it was used by dentists in general dental practice. 19 general dental practitioners were visited at their clinics. Ambient light (illuminance) was measured in the rooms where the monitors were placed. Different technical display parameters we...

The number of dentists who have converted from conventional film radiography to digital radiography continues to grow. A digital system has numerous advantages, but there are also many new aspects to consider. The overall aim of this thesis was to study how digital radiography was used in general dental practices. The specific aims were to study ho...

The aim was to evaluate the experiences of Swedish general dental practitioners (GDPs) with digital radiography and their opinion on the same, particularly regarding quality issues. A letter was sent to all GDPs in private care in Region Skåne, Sweden, asking whether they used digital radiography (n=513). The response rate was 79%. The number of pr...

In July 2002, a new dental insurance program was introduced in Sweden. For all patients over 65 years, prior approval for all prosthetic work would need to be obtained from the Dental Insurance Office. From October to December 2002, 540 cases were randomly selected for evaluation from the 14,624 applications that had been sent from throughout Swede...