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  • 1.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    The temporomandibular joint: Tomopraphic and CT assesment of its bone demarcations with reference to adjacent organs1998Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The wall of the temporal bone separating the temporomandibular joint (TMJ) from surroundings organs, can be very thin and also have development defects. Distortion effects in the radiographic reproduction of these bone walls can result in misinterpretations when exanimating suspected pathologic changes in the region. These areas need to be radiographic identified prior to taking any invasive measures. Incorrect assessment of bone thickness may lead to serious sequelae due to the risk of penetration injury during invasive investigation or treatment of the TMJ or ear. The purpose of this project was to gain more detailed knowledge about the anatomy and topography of the TMJ with special reference to its bone demarcations regarding adjacent organs and to evaluate the tomographic and computed tomographic (CT) depiction of these bone walls. To obtain a basic analysis of the tissue anatomy and tomographic and CT reproduction of the TMJ region, autopsy specimens were studied. After CT and conventional tomography, the specimens were sectioned in a microtom. Three- dimensional orientation systems allowed identification of section depth in the radiograms and in the histologic sections, allowing the radiograms in turn to be correlated with the true anatomy. The angle of inclination relative to the perpendicular to established imaging planes the bone walls studied was examined in three projections in order to identify regions where the bone demarcation showed an unfavorable inclination regarding the possibility of valid radiographic representation. The thickness of the bone wall between the TMJ and the middle cranial fossa, measured in the thinnest part, varied between 0.08 and 3.62 mm, averaging 1.14 mm. The bone wall between the TMJ and the middle ear showed less variation in thickness ranging from 0.00 to 1.80 mm. The thickness of the bone wall separating the TMJ from the external auditory canal varied between  1.50 mm (lateral part) and 1.21 mm (central part), with a range of between 0.21 and 4.10 mm. Development defects of this bone wall were found in 5.2 % of the examined joints. The validity in tomographic depiction of these walls was highly dependent on an optimal orientation of the bone wall in relation to the image plane. The variations in the anatomy and sagittal dimension of the external auditory canal led to variations in tomographic blurring, and suggested the need for examinations after patient repositioning in cases of suspected bone resorbing lesions so that image aberration due to unfavorable inclination of the bone wall relative to the image plane may be excluded. CT of these bone walls was valid (± 10 %) for walls thicker than approximately 1 mm, forming an angle of less than 35® with the perpendicular to the scan plane when the bone wall thickness was determined as the full-width-at-half-maximum (FWHM). For bone walls thinner than 1 mm, and for those thicker than 1 mm and at an angle exceeding 35®, partial volume averaging effects resulted in a progressively increasing magnification of bone dimensions. Observer estimations of bone thickness from images obtained using conventional bone window settings (c=400, W=2000) showed good agreement for bone walls thicker than 1 mm and with an angle of inclination relative to the perpendicular to the image plane of less than approximately 25®. For bone walls thinner than 1 mm and for thicker than 1 mm with an inclination exceeding approximately 25®, the estimations resulted in a progressively increasing overestimation amounting 200% for gracile bone walls with an inclination of 45® to 50®. Determination of width or absence of the central white zone in images obtained with the described parameters could help to reduce the risk of overestimation of bone thickness. A considerable part of the bone walls separating the TMJ from the middle cranial fossa and the external auditory canal/middle ear, respectively, have dimensions and inclinations to established imaging planes used at TMJ examinations that make the depiction of these walls highly susceptible to image distortion. 

  • 2.
    Ahlqvist, Jan B
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Nilsson, Tore A
    Umeå University, Faculty of Medicine, Department of Odontology.
    Hedman, Leif R
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Desser, Terry S
    Dev, Parvati
    Johansson, Magnus
    Umeå University, Faculty of Medicine, Department of Odontology.
    Youngblood, Patricia L
    Cheng, Robert P
    Gold, Garry E
    A randomized controlled trial on 2 simulation-based training methods in radiology: effects on radiologic technology student skill in assessing image quality.2013In: Simulation in Healthcare: The Journal of the Society for Simulation in Healthcare, ISSN 1559-2332, E-ISSN 1559-713X, Vol. 8, no 6, p. 382-387Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: A simulator for virtual radiographic examinations was developed. In the virtual environment, the user can perform and analyze radiographic examinations of patient models without the use of ionizing radiation. We investigated if this simulation technique could improve education of radiology technology students. We compared student performance in the assessment of radiographic image quality after training with a conventional manikin or with the virtual radiography simulator.

    METHODS: A randomized controlled experimental study involving 31 first-year radiology technology students was performed. It was organized in 4 phases as follows: (I) randomization to control or experimental group based on the results of an anatomy examination; (II) proficiency testing before training; (III) intervention (control group, exposure and analysis of radiographic images of the cervical spine of a manikin; experimental group, exposure and analysis of the cervical spine images in the virtual radiography simulator); and (IV) proficiency testing after training.

    RESULTS: The experimental group showed significantly higher scores after training compared with those before training (P < 0.01). A linear mixed-effect analysis revealed a significant difference between the control and experimental groups regarding proficiency change (P = 0.01).

    CONCLUSIONS: Virtual radiographic simulation is an effective tool for learning image quality assessment. Simulation can therefore be a valuable adjunct to traditional educational methods and reduce exposure to x-rays and tutoring time.

  • 3.
    Ahlqvist, Jan
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Bryndahl, Frerik
    Umeå University, Faculty of Medicine, Department of Odontology.
    Eckerdal, Olof
    Isberg, Annika
    Sources of radiographic distortion in conventional and computed tomography of the temporal bone.1998In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 27, no 6, p. 351-7Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To identify those bony regions of the glenoid fossa where, due to the inclination, there is an increased risk of radiographic distortion in conventional and computed tomography (CT).

    METHODS: The inclination of the roof and posterior wall of the glenoid fossa was determined relative to established imaging planes. Measurements were performed on 50 corrected coronal MR and 50 axial CT images and 200 sagittal cryosections of 50 temporomandibular joints (TMJs). The location of regions with unfavourable bone wall inclination was identified using the condyle as a reference.

    RESULTS: The inclination of parts of the fossa roof exceeded the limit for reliable depiction in corrected sagittal and coronal planes in 40% and 8% of the joints respectively. The inclination of parts of the posterior wall of the fossa exceeded the limit for reliable depiction in corrected sagittal and in true sagittal planes in 100% and 84% of the joints respectively. In 84% of the joints the inclination exceeded the limit for reliable depiction in the axial plane. For both bone walls the regions with unfavourable inclination were in the medial part of the joint.

    CONCLUSIONS: The angulation of parts of the roof and posterior wall of the glenoid fossa in relation to established imaging planes makes them highly susceptible to distortion. The oblique coronal projection is well suited for depiction of the roof of the fossa and preferable to a sagittal projection. An oblique axial projection is required for the posterior wall.

  • 4. Ahlqvist, Jan
    et al.
    Eliasson, S
    Welander, U
    The effect of projection errors on cephalometric length measurements1986In: European Journal of Orthodontics, ISSN 0141-5387, E-ISSN 1460-2210, Vol. 8, no 3, p. 141-148Article in journal (Refereed)
    Abstract [en]

    The magnitude of projection errors, calculated theoretically on length measurements in cephalometry was studied. Rotation of the object by up to 5° from the proper position, resulted in errors in length measurements that were usually less than one percent. Rotations of more than 5° may increase the error but imply misalignments of the head that should be evident when positioning the patient. The advantage of extremely long focus film distances seems doubtful.

  • 5. Ahlqvist, Jan
    et al.
    Eliasson, S
    Welander, Ulf
    The cephalometric projection. Part II. Principles of image distortion in cephalography.1983In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 12, no 2, p. 101-8Article in journal (Refereed)
  • 6. Ahlqvist, Jan
    et al.
    Eliasson, S
    Welander, Ulf
    The effect of projection errors on angular measurements in cephalometry.1988In: European Journal of Orthodontics, ISSN 0141-5387, E-ISSN 1460-2210, Vol. 10, no 4, p. 353-61Article in journal (Refereed)
  • 7.
    Ahlqvist, Jan
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Isberg, A M
    Umeå University, Faculty of Medicine, Department of Odontology.
    Bone demarcation of the temporomandibular joint. Validity of clinical assessment of bone thickness by means of CT.1998In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 39, no 6, p. 649-55Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To study the CT depiction of bone demarcations in the temporomandibular joint, using conventional window level and window width; and to evaluate observer performance in estimating bone thickness in these images.

    MATERIAL AND METHODS: Seven joint specimens were imaged by CT and then cryosectioned. The measurements of bone wall thickness in the images were compared to the true bone thickness at each cutting level. In addition, 4 experienced radiologists estimated the thickness of the bone walls in the images.

    RESULTS: The relative difference between the CT reproduction and the true bone thickness was small for bone walls thicker than 2 mm. This difference increased with the decrease in bone thickness and the increase in the inclination of the bone wall from the perpendicular to the image plane. Bone walls thinner than 1 mm were reproduced as considerably thicker than their true thickness. This resulted in a clinical overestimation of bone thickness.

    CONCLUSION: Both the CT representation and the interpretation of bone demarcation in the temporomandibular joint may constitute a problem. Partial volume averaging effects can result in an overestimation of bone dimensions amounting to 200% for thin bones. The central white zone in images of thin bone walls obtained with the parameters described here could serve as an indicator that could help to reduce the risk of overestimating bone thickness.

  • 8.
    Ahlqvist, Jan
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Isberg, Annika
    Umeå University, Faculty of Medicine, Department of Odontology.
    Validity of computed tomography in imaging thin walls of the temporal bone1999In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 28, no 1, p. 13-19Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To evaluate the validity of computed tomography (CT) for reproduction of the bone margins of the temporomandibular joint (TMJ).

    METHODS: Seven TMJ specimens were examined with a CT and then cryosectioned. The bone separating the TMJ from the middle cranial fossa, middle ear and external auditory canal was measured as the full width at half maximum (FWHM). Measurements were compared with the true thickness of the bone wall.

    RESULTS: There was good agreement when the bone walls were thicker than 1 mm: accuracy was influenced only by the angle of the bone wall to the scanning plane. Conversely, bone walls thinner than 1 mm were reproduced with a magnification that increased with decreasing bone thickness. The difference increased further as the inclination of the bone wall became greater.

    CONCLUSION: Measurements performed at FWHM are reliable within +/- 10% for bone walls more than approximately 1 mm thick which form an angle of less than 35 degrees to the perpendicular of the scanning plane. For bone walls thinner than 1 mm and for those thicker than 1 mm with an inclination exceeding approximately 35 degrees, partial volume effects result in a progressively increasing magnification of bone thickness.

  • 9. Ahlqvist, Jan
    et al.
    Legrell, Per Erik
    A technique for the accurate administration of corticosteroids in the temporomandibular joint.1993In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 22, no 4, p. 211-3Article in journal (Refereed)
    Abstract [en]

    A new technique for intra-articular injection of a corticosteroid in the temporomandibular joint (TMJ) is presented. The corticosteroid is mixed with contrast medium and the administration visualized and controlled using fluoroscopy. When superior and inferior joint spaces have been filled and the soft tissues of the joint have been identified in the fluoroscopic image, additional corticosteroid can be administered to selected sites within the TMJ.

  • 10. Eckerdal, O
    et al.
    Ahlqvist, Jan
    External bony auditory canal and the tympanic bone. Morphologic properties and influences on the tomographic reproduction.1980In: Acta radiologica: diagnosis, ISSN 0567-8056, Vol. 21, no 3, p. 425-31Article in journal (Refereed)
    Abstract [en]

    The external bony auditory canal is morphologically defined as concerns the shape and calibre in successive plane parallel histologic sections of the petrous bone. The sagittal dimensions and structural appearances of the tympanic bone are demonstrated. The morphologic properties defined constitute a basis for the evaluation of the tomographic image formation in this region.

  • 11. Eckerdal, Olof
    et al.
    Ahlqvist, Jan
    Thin bony walls of the temporomandibular joint. Morphologic properties and tomographic reproduction.1979In: Acta radiologica: diagnosis, ISSN 0567-8056, Vol. 20, no 2, p. 385-92Article in journal (Refereed)
    Abstract [en]

    The morphology of two thin bony walls in the medial third of the mandibular fossa is described on the basis of successive microtome sections of undecalcified temporomandibular joint specimens. The requirements for reproduction on thin bony walls at tomography with hypocycloidal movement are defined and discussed.

  • 12. Eckerdal, Olof
    et al.
    Ahlqvist, Jan
    Alehagen, U
    Wing, K
    Length dimensions and morphologic variations of the external bony auditory canal. A radiographic and histologic investigation.1978In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 7, no 1, p. 43-50Article in journal (Refereed)
  • 13. Eliasson, S
    et al.
    Welander, U
    Ahlqvist, Jan
    The cephalographic projection. Part I: General considerations.1982In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 11, no 2, p. 117-22Article in journal (Refereed)
  • 14.
    Fridell, Sara
    et al.
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology.
    The use of dental radiographs for identification of children with unrestored dentitions.2006In: The Journal of Forensic Odonto-Stomatology, Vol. 24, no 2, p. 42-46Article in journal (Refereed)
    Abstract [en]

    The success of dental identification is often dependent on the extent of previous dental care and the location of detailed dental records. However, several factors limit available comparable data among children. There are often no clinical indications for dental radiography before the age of five and many children and adolescents have no restorative care. This reduces the amount of individualizing information suitable for comparative identification. The aim of this study was to investigate matching of dental x-rays from children without fillings at different ages, and to see if radiographic expertise facilitated radiographic comparison. Five general dental practitioners (GDP) and five oral and maxillofacial radiologists (OMR) attempted to match bitewing examinations from 30 children. The results showed that dentists are likely to match bitewing radiographs in these conditions. This likelihood is further enhanced when oral and maxillofacial radiologists compare images. This suggests that manual comparison of bitewings from children allow sufficient concordant visible points for identification to occur.

  • 15.
    Garoff, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology.
    Johansson, Elias
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Wester, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Department of Clinical Sciences, Karolinska Insititutet, Danderyds hospital, Stockholm.
    Carotid calcification in panoramic radiographs: radiographic appearance and the degree of carotid stenosis2016In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 45, no 6, article id 20160147Article in journal (Refereed)
    Abstract [en]

    Objectives: Approximately 7% of patients examined with panoramic radiographs (PRs) for odontological reasons, and with incidental findings of carotid artery calcification (CAC), have significant (≥50%) carotid stenosis (SCS). The aim of this study was to determine if the radiographic appearance of CACs in PRs could be categorized such that we could improve the positive-predictive value (PPV) for SCS detection.

    Methods: This cross-sectional study included 278 patients with CACs identified by PRs, 127 with SCS and 151 without SCS. CACs were categorized based on the following appearances: (1) single, (2) scattered or (3) vessel-outlining. Correlates were derived for each category according to positivity or not for SCS in the corresponding neck sides. For a representative adult population (in dentistry) presenting with CACs in PRs, PPVs for SCS prediction were then calculated for three subgroups based on different combinations of appearances (2) and/or (3).

    Results: Vessel-outlining CACs corresponded to 65% of neck sides with SCS vs 47% without SCS (p < 0.001). Single CACs corresponded to 15% of neck sides with SCS vs 27% without SCS (p = 0.006). Scattered CACs corresponded to 20% of neck sides with SCS vs 26% without SCS (p  = 0.127). In the representative population, the PPVs for SCS detection were comparable (7.2–7.8%) for all three subgroups and when the presence of a CAC is the sole criterion (7.4%).

    Conclusions: Stratifying the radiographic appearance of CACs in PRs does not improve the PPV for SCS detection. Whether different radiographic appearances are associated with future risk of stroke, or other cardiovascular events, remains unknown.

  • 16.
    Garoff, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Johansson, Elias
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Arnerlöv, Conny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology.
    Wester, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Calcium quantity in carotid plaques: detection in panoramic radiographs and association with degree of stenosis2015In: Oral surgery, oral medicine, oral pathology and oral radiology, ISSN 2212-4403, E-ISSN 2212-4411, Vol. 120, no 2, p. 269-274Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To determine calcium volume in extirpated carotid plaques, analyze correlations between calcium volume and degree of stenosis, and analyze whether calcium volume influences the possibility of detecting stenosis in panoramic radiographs.

    STUDY DESIGN: Ninety-seven consecutive patients with ultrasonography-verified carotid stenosis were examined with panoramic radiography before surgery. Extirpated carotid plaques (n = 103) were analyzed for calcium volume by cone beam computed tomography (CBCT). Panoramic radiographs were analyzed for carotid calcifications.

    RESULTS: The median calcium volume was 45 mm(3) (first quartile subtracted from the third quartile [IQR], 14-98 mm(3)). We observed no correlation between calcium volume and degree of stenosis. Seventy-eight stenoses were situated within the region included in the panoramic radiographs, and their volumes ranged from 0 to 509 mm(3). Of these, 99% revealed carotid calcifications on panoramic radiographs.

    CONCLUSIONS: We found no association between calcium volume and degree of carotid stenosis. Calcium volume did not influence the possibility of detecting carotid calcifications in panoramic radiographs.

  • 17.
    Garoff, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Johansson, Elias
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology.
    Arnerlöv, Conny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Wester, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Detection of calcifications in panoramic radiographs in patients with carotid stenoses ≥50%2014In: Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics, ISSN 1079-2104, E-ISSN 1528-395X, Vol. 117, no 3, p. 385-391Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: Carotid stenoses ≥50% are associated with increased risk for stroke that can be reduced by prophylactic carotid endarterectomy (CEA). Calcifications in arteries can be detected in panoramic radiographs (PRs). In a cross-sectional study, we analyzed (1) extirpated plaques for calcification, (2) how often PRs disclosed calcified plaques, (3) how often patients with stenoses ≥50% presented calcifications in PRs, and (4) the additional value of frontal radiographs (FRs).

    STUDY DESIGN: Patients (n = 100) with carotid stenosis ≥50% were examined with PRs and FRs before CEA. Extirpated carotid plaques were radiographically examined (n = 101).

    RESULTS: It was found that 100 of 101 (99%) extirpated plaques were calcified, of which 75 of 100 (75%) were detected in PRs; 84 of 100 (84%) patients presented carotid calcifications in the PRs, in 9.5% contralateral to the stenosis ≥50%.

    CONCLUSIONS: Carotid calcifications are seen in PRs in 84% of patients with carotid stenosis ≥50%, independent of gender. FRs do not contribute significantly to this identification.

  • 18.
    Gustafsson, Nils
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ahlqvist, Jan B.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Näslund, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Wester, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Department of Clinical Sciences, Karolinska Institutet Danderyds Hospital, Stockholm, Sweden..
    Buhlin, Kare
    Gustafsson, Anders
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology.
    Calcified carotid artery atheromas in panoramic radiographs are associated with a first myocardial infarction: a case-control study2018In: Oral surgery, oral medicine, oral pathology and oral radiology, ISSN 2212-4403, E-ISSN 2212-4411, Vol. 125, no 2, p. 199-205Article in journal (Refereed)
    Abstract [en]

    Objective. The aim of this case-control study was to investigate whether patients with a first myocardial infarction (MI) had a higher prevalence of calcified carotid artery atheromas (CCAAs) on panoramic radiographs (PRs) than age-, gender-, and residential area-matched controls without MI. Study Design. Six hundred ninety-six cases with a first MI and 696 controls were included in this substudy of the Swedish multicentre PAROKRANK study. All participants underwent panoramic radiography, and the PRs were evaluated for CCAAs. Results. The prevalence of CCAAs detected by PR was 33.8% (235 of 696) in cases and 27.6% (192 of 696) in controls (odds ratio [OR] 1.24; 95% confidence interval [CI] 1.04-1.44; P = .012). Among males, 32.7% of cases (184 of 562) and 26.5% of controls (149 of 562) displayed CCAAs on PRs (OR 1.24; 95% CI 1.03-1.48; P = .022). Among both genders, bilateral CCAAs were significantly more common among cases than among controls (P = .002). Conclusions. Cases with recent MIs had a significantly higher prevalence of CCAAs on PRs compared with controls without MIs. This difference between groups was more pronounced for bilateral CCAAs. These findings supported the hypothesis that CCAA detection could serve as a risk indicator for future MIs.

  • 19.
    Gustafsson, Nils
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology.
    Long-term skill improvement among general dental practitioners after a short training programme in diagnosing calcified carotid artery atheromas on panoramic radiographs2019In: European journal of dental education, ISSN 1396-5883, E-ISSN 1600-0579, Vol. 23, p. 54-61Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To study general dental practitioners (GDPs) ability to detect calcified carotid artery atheromas (CCAAs) in panoramic radiographs (PRs) and if their diagnostic accuracy in long term is improved after a short training programme.

    METHODS: Fourteen GDPs had their diagnostic accuracy regarding CCAA in PR assessed at baseline, 2 weeks and 1 year after training. Comparison was made with a reference standard based on consensus results from two experienced oral and maxillofacial radiologists. At each session, 100 radiographs were assessed individually by the GDPs. After the baseline assessment, the GDPs participated in a 2-hour training programme comprising a lecture and diagnostic training by calibration. The GDPs results before and after training were compared, as well as between follow-up sessions.

    RESULTS: A significant improvement in diagnostic accuracy was observed with increased sensitivity (from 41.8% to 55.7%, P = 0.02) without a significant decrease in specificity (from 87.2% to 86.7%, P = 0.87). The Kappa values also increased (from 0.66 to 0.71, P = 0.04). At 1-year follow-up, the improvement compared to baseline remained significant. There were no significant changes between the 2-week and 1-year follow-up assessment.

    CONCLUSION: A short training programme can significantly and sustainable improve GDPs diagnostic accuracy regarding CCAA.

  • 20.
    Häll, Lars O
    et al.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Söderström, Tor
    Umeå University, Faculty of Social Sciences, Department of Education.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Nilsson, Tore
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Collaborative learning with screen-based simulation in health care education: an empirical study of collaborative patterns and proficiency development2011In: Journal of Computer Assisted Learning, ISSN 0266-4909, E-ISSN 1365-2729, Vol. 27, no 5, p. 448-461Article in journal (Refereed)
    Abstract [en]

    This article is about collaborative learning with educational computer-assisted simulation(ECAS) in health care education. Previous research on training with a radiological virtual reality simulator has indicated positive effects on learning when compared to a more conventional alternative. Drawing upon the field of Computer-Supported Collaborative Learning, we investigate collaborative patterns, their causes, and their implications for learning. We investigate why the extent of application of subject-specific terminology differs between simulation training and more conventional training. We also investigate how the student-simulator interaction affordances produce collaborative patterns and impact learning. Proficiency tests before and after training, observations during training, and interviews after training constitute the empirical foundation. Thirty-six dentistry students volunteered for participation. The results showed that not only the task but also the medium of feedback impacts the application of subject-specific terminology. However, no relation to proficiency development was revealed.We identified turn-taking as well as dominance patterns of student-simulator interaction but again found no relation to proficiency development. Further research may give us deeper insights into if and how these collaborative patterns, in other respects, impact collaborative learning with ECAS in health care education.

  • 21.
    Häll, Lars-Olof
    et al.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Söderström, Tor
    Umeå University, Faculty of Social Sciences, Department of Education.
    Nilsson, Tore
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Integrating computer based simulation training into curriculum: complicated and time consuming?2009In: Readings in Technology and Education: Proceedings of ICICTE 2009 / [ed] Fernstrom Ken, University of the Fraser Valley Press , 2009, p. 90-98Conference paper (Refereed)
  • 22.
    Ibrahimi, Pranvera
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Jashari, Fisnik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Arnerlöv, Conny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Garoff, Maria
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Johansson, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology.
    Wester, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Henein, Michael Y
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Carotid ultrasound accurately detects arterial calcification quantified by cone beam computed tomography2014In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 35, no Supplement 1, Meeting abstract P3519, p. 636-636Article in journal (Other academic)
  • 23.
    Jashari, Fisnik
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Ibrahimi, Pranvera
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Johansson, Elias
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Arnerlöv, Conny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Garoff, Maria
    Umeå University, Faculty of Medicine, Department of Odontology.
    Jäghagen, Eva Levring
    Umeå University, Faculty of Medicine, Department of Odontology.
    Wester, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Henein, Michael Y
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Atherosclerotic Calcification Detection: A Comparative Study of Carotid Ultrasound and Cone Beam CT2015In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 16, no 8, p. 19978-19988Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND AIM: Arterial calcification is often detected on ultrasound examination but its diagnostic accuracy is not well validated. The aim of this study was to determine the accuracy of carotid ultrasound B mode findings in detecting atherosclerotic calcification quantified by cone beam computed tomography (CBCT).

    METHODS: We analyzed 94 carotid arteries, from 88 patients (mean age 70 ± 7 years, 33% females), who underwent pre-endarterectomy ultrasound examination. Plaques with high echogenic nodules and posterior shadowing were considered calcified. After surgery, the excised plaques were examined using CBCT, from which the calcification volume (mm3) was calculated. In cases with multiple calcifications the largest calcification nodule volume was used to represent the plaque. Carotid artery calcification by the two imaging techniques was compared using conventional correlations.

    RESULTS: Carotid ultrasound was highly accurate in detecting the presence of calcification; with a sensitivity of 88.2%. Based on the quartile ranges of calcification volumes measured by CBCT we have divided plaque calcification into four groups: <8; 8-35; 36-70 and >70 mm3. Calcification volumes ≥8 were accurately detectable by ultrasound with a sensitivity of 96%. Of the 21 plaques with <8 mm3 calcification volume; only 13 were detected by ultrasound; resulting in a sensitivity of 62%. There was no difference in the volume of calcification between symptomatic and asymptomatic patients.

    CONCLUSION: Carotid ultrasound is highly accurate in detecting the presence of calcified atherosclerotic lesions of volume ≥8 mm3; but less accurate in detecting smaller volume calcified plaques. Further development of ultrasound techniques should allow better detection of early arterial calcification.

  • 24.
    Johansson, Elias
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Garoff, Maria
    Umeå University, Faculty of Medicine, Department of Odontology.
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology.
    Meimermondt, Amanda
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Wester, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Carotid calcifications on panoramic radiographs: a 5-year follow-up study2015In: Oral surgery, oral medicine, oral pathology and oral radiology, ISSN 2212-4403, E-ISSN 2212-4411, Vol. 120, no 4, p. 513-520Article in journal (Refereed)
    Abstract [en]

    Objective. The aim of this study was to determine whether people with calcifications in the area of the carotid arteries on panoramic radiographs (CALPANs) have an increased prevalence of vascular risk factors or an increased risk of future vascular events. Materials and Methods. We included 113 consecutive patients with CALPANs and 116 gender- and age-matched controls without CALPANs. Vascular risk factors were generally known in the study population, since it was recorded in a population-based community-screening program. Results. Patients with CALPANs had a higher prevalence of vascular risk factors than controls independent of previous vascular events. During the 5.4-year follow-up, patients with CALPANs had a higher risk of a combined endpoint of vascular events (5.6%/yr) compared with the controls (2.4%/yr) (P = .004 by log rank test; unadjusted hazard ratio (HR) 2.4; 95% CI 1.3-4.3). This difference was not significant when previous vascular events and risk factors were taken into account (adjusted HR; 1.2; 95% CI 0.6-2.3; P = .62; Cox regression). Conclusions. People with CALPANs are very likely to have vascular risk factors, but these factors might be unknown when CALPANs are detected. Accordingly, patients with CALPANs should be advised to have their vascular risk factors regularly checked in order to receive advice on preventive lifestyle modifications and medical treatment when indicated. However, it remains unknown whether CALPANs add information about the independent risk of future vascular events. Therefore, further studies are warranted to investigate whether the detection of CALPANs indicates a need for additional or more intense vascular treatment.

  • 25.
    Johansson, Elias P
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Garoff, Maria
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Karp, Kjell
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Wester, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ultrasound screening for asymptomatic carotid stenosis in subjects with calcifications in the area of the carotid arteries on panoramic radiographs: a cross-sectional study2011In: BMC Cardiovascular Disorders, ISSN 1471-2261, E-ISSN 1471-2261, Vol. 11, no 44, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Background: Directed ultrasonic screening for carotid stenosis is cost-effective in populations with > 5% prevalence of the diagnosis. Occasionally, calcifications in the area of the carotid arteries are incidentally detected on odontological panoramic radiographs. We aimed to determine if directed screening for carotid stenosis with ultrasound is indicated in individuals with such calcifications. Methods: This was a cross-sectional study. Carotid ultrasound examinations were performed on consecutive persons, with findings of calcifications in the area of the carotid arteries on panoramic radiography that were otherwise eligible for asymptomatic carotid endarterectomy. Results: Calcification in the area of the carotid arteries was seen in 176 of 1182 persons undergoing panoramic radiography. Of these, 117 fulfilled the inclusion criterion and were examined with carotid ultrasound. Eight persons (6.8%; 95% CI 2.2-11.5%) had a carotid stenosis - not significant over the 5% pre-specified threshold (p = 0.232, Binomial test). However, there was a significant sex difference (p = 0.008), as all stenoses were found in men. Among men, 12.5% (95% CI 4.2-20.8%) had carotid stenosis - significantly over the 5% pre-specified threshold (p = 0.014, Binomial test). Conclusions: The incidental finding of calcification in the area of the carotid arteries on panoramic radiographs should be followed up with carotid screening in men that are otherwise eligible for asymptomatic carotid endarterectomy.

  • 26.
    Johansson, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Bladh, Magnus
    Umeå University, Faculty of Medicine, Department of Odontology.
    Sjöström, Mats
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    The use of intraoral radiographs for identification of edentulous patients rehabilitated with implants2016In: Journal of Forensic Odonto-Stomatology, ISSN 0258-414X, E-ISSN 2219-6749, Vol. 34, no 1, p. 1-9Article in journal (Refereed)
    Abstract [en]

    The aims of this study were; i) to determine the accuracy by which two intra-oral radiographic examinations performed on patients with edentulous mandibles treated with dental implants can be matched. ii) to determine whether prosthodontic supra-construction is important for matching. iii) to investigate whether there is a difference between oral and maxilla-facial radiologists (OMR) and dental practitioners, not specialized in oral and maxillofacial radiology (NOMR), regarding their ability to match. The specific features of the radiographs used by the operators to acquire a match were also investigated. Intra-oral radiographic examinations from 59 patients were utilized. Radiographic examinations from 47 patients carried out at placement of the supra-construction and at subsequent follow-up examinations were used as "ante-mortem" and "post-mortem" records respectively. Examinations from 12 patients were added to the "post-mortem" records without "ante-mortem" records being available. The study was divided into two parts. In Part One all "ante"- and "post-mortem" records had the supra-construction masked and in Part Two it was visible. Seven dentists (4 OMR, 3 NOMR) were instructed to specify on what basis each matching was made on the confidence of a three-graded scale OMR had 93.2 % and 98.5 % accuracy in Parts One and Two respectively. NOMR had 63.8 % and 87.9 %. Bone anatomy was the most commonly used feature by OMR to obtain a match. For NOMR it was the appearance of the fixtures. OMR reported higher confidence in their ability to match the examinations. This study indicates that OMR could be a valuable resource in cases of identification where dental implants are a feature of the post-mortem dental records.

  • 27.
    Nilsson, Tore A
    et al.
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology.
    Hedman, Leif
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Ahlqvist, Jan B
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology.
    A Randomized Trial of Simulation-Based Versus Conventional Training of Dental Student Skill at Interpreting Spatial Information in Radiographs.2007In: The Journal of the Society for Simulation in Healthcare.: Simulation in Healthcare:, ISSN 1559-2332, Vol. 2, no 3, p. 164-169Article in journal (Refereed)
    Abstract [en]

    Abstract Introduction: A radiology simulator has been developed. We tested the simulator with students in an oral radiology program for training interpretation of spatial relations in radiographs utilizing parallax. The aim of the study was to compare learning outcome regarding interpretative skill after training in the simulator vs. after conventional training.

    Methods: Fifty-seven dental students voluntarily participated in a randomized experimental study. The participants' proficiency in interpretation of spatial information in radiographs and their visual-spatial ability was assessed. Proficiency was assessed by a test instrument designed by the authors and visual-spatial ability with the Mental Rotations Test, version A (MRT-A). Randomization to training group was based on pre-training proficiency test results. The experimental group trained in the simulator and the control group received conventional training. Training lasted for 90 minutes for both groups. Immediately after training a second proficiency test was performed.

    Results: The proficiency test results were significantly higher after training for the experimental group (P <= 0.01), but not for the control group. Univariate variance analysis of difference in proficiency test score revealed a significant interaction effect (P = 0.03) between training group and MRT-A category; in the experimental group there was a stronger training effect among students with low level of MRT-A.

    Conclusions: Training in the simulator improved skill in interpreting spatial information in radiographs when evaluated immediately after training. For individuals with low visual-spatial ability simulator based training seems to be more beneficial than conventional training.

  • 28.
    Nilsson, Tore A.
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology. Univ Hosp, Oral & Maxillofacial Radiol Clin, SE-90185 Umea, Sweden.
    Hedman, Leif R
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Ahlqvist, Jan B
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Dental student skill retention eight months after simulator-supported training in oral radiology2011In: Journal of dental education, ISSN 1930-7837, Vol. 75, no 5, p. 679-684Article in journal (Refereed)
    Abstract [en]

    The purpose of this project was to investigate the long-term effects on skill to interpret spatial information in radiographs after conventional and simulator-supported training. The study was a follow-up of a previously reported randomized experimental study. The original study population was comprised of fifty-seven dental students. Forty-five individuals agreed to participate in a follow-up study eight months after completion of the original study. During the time interval between completion of the previous study and the follow-up study, the participants underwent an examination in oral radiology and had theoretical and clinical training in other topics than oral radiology. Skill at interpreting spatial information in radiographs was assessed with a previously used test instrument. The test instrument was identical with the instrument used for baseline assessment in the original study. The results showed that the skill to interpret spatial relations in radiographs eight months after completion of simulator-supported training was significantly better (p=0.01) than before training. The conventional training showed almost the same pattern, but the difference was smaller and not statistically significant (p=0.11). It is concluded that simulator-supported training is a valuable adjunct to conventional educational methods in oral radiology.

  • 29.
    Nilsson, Tore
    et al.
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology.
    Ahlqvist, Jan
    Johansson, Magnus
    Isberg, Annika
    Virtual reality for simulation of radiographic projections: validation of projection geometry2004In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 33, no 1, p. 44-50Article in journal (Refereed)
    Abstract [en]

    Objective: To develop a software for virtual reality (VR) simulation of X-ray images based on perspective projections through a patient model derived from data from a CT examination and to evaluate the accuracy in the projection geometry obtained by the software.

    Methods: A VR software was developed on a personal computer, with models of a patient, an X-ray machine and a detector. The model of the patient was derived from data from a CT examination of a dry skull. Simulated radiographic images of the patient model could be rendered as perspective projections based on the relative positions between the models. The projection geometry of the software was validated by developing an artificial CT data set containing high attenuation points as objects to be imaged. The accuracy in projection geometry was evaluated in a systematic way. The distances between two dots, representing the projected test points in the simulated radiographic images, were measured. They were compared with theoretical calculations of the corresponding distances using traditional mathematical tools.

    Results: The difference between the simulated and calculated projected distances never exceeded 0.5 mm. The error in simulated projected distances was in most cases within 1%. No systematic errors were revealed.

    Conclusion: The software, developed for personal computers, can produce simulated X-ray images with high geometric accuracy based on perspective projections through a CT data set. The software can be used for simulation of radiographic examinations.

  • 30.
    Nilsson, Tore
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Hedman, Leif
    Ahlqvist, Jan
    Retention of dental student skill at interpreting spatial information in radiographs after radiology simulator trainingManuscript (preprint) (Other (popular science, discussion, etc.))
  • 31.
    Nilsson, Tore
    et al.
    Umeå University, Faculty of Medicine, Odontology.
    Hedman, Leif
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology. Oral diagnostisk radiologi.
    Visual-spatial ability and interpretation of three-dimensional information in radiographs2007In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 36, p. 86-91Article in journal (Refereed)
    Abstract [en]

    Objectives: To investigate whether skill in the interpretation of three-dimensional (3D) information in radiographs utilizing the parallax phenomenon is associated with visual-spatial ability and whether development of this skill is related to visual-spatial ability.

    Methods: Eighty-six individuals with a median age of 25 years participated in the study. It was organized into three parts: (1) assessment before training, (2) training in object depth localization utilizing parallax and (3) assessment after training. Before training, visual-spatial ability was assessed with a mental rotation test, MRT-A; skill in interpreting 3D information was assessed with two specifically designed proficiency tests: a radiography test, which assessed the ability to interpret 3D information in radiographs utilizing motion parallax and a principle test which assessed understanding of the principles of motion parallax. After training, skill in interpreting 3D information was reassessed. Improvement was defined as the difference between test scores after training and before training. Multiple linear regression was used to analyse the effect of student and training characteristics on proficiency test results and improvement.

    Results: Radiography test results after training and improvement of radiography test results were significantly associated with MRT-A scores (P<0.001 and P=0.020, respectively). Principle test results were high before training and did not improve after training. The test results were associated with MRT-A both before (P=0.009) and after training (P=0.003).

    Conclusions: Understanding of the parallax phenomenon is associated with visual-spatial ability. Development of the skill to interpret 3D information in radiographs utilizing parallax is facilitated for individuals with high visual-spatial ability.

  • 32.
    Nyström, Elisabeth
    et al.
    Umeå University, Faculty of Medicine, Odontology. Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Surgery.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Odontology. Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology.
    Gunne, Johan
    Umeå University, Faculty of Medicine, Odontology.
    Kahnberg, KE
    10-year follow-up of onlay bone grafts and implants in severely resorbed maxillae.2004In: International Journal of Oral and Maxillofacial Surgery, Vol. 33, no 3, p. 258-62Article in journal (Refereed)
    Abstract [en]

    Thirty patients with extremely resorbed maxillae had reconstructive bone grafts from the ala iliaca and endosseous implants in a one-stage procedure. The first ten patients constituted a development group and the following 20 patients a routine group. The marginal bone level and implants success rate was evaluated in a prospective long-term follow-up for a minimum of 10 years (10-13 years). Clinical and radiographic examinations were performed at 6 months and then annually up to 5 years. The final examinations were performed at the 10-year follow-up. The bridges were removed at every clinical examination. Marginal bone loss was seen up to the 3-year examination, where it averaged 4.6 mm in the routine group. Between the 3- and 10-year follow-up no significant change was registered. The initial bone loss was probably due to the design of the 3.6 mm conical unthreaded marginal part of the implant. The implant success rate was 83.1% in the routine group. Failures mostly occurred during the first 2 years (14 out of 20). A substantial amount of bone can be gained in patients with extremely resorbed maxillae, when treated with bone graft according to the procedure described in this study.

  • 33.
    Nyström, Elisabeth
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery.
    Ahlqvist, Jan
    Kahnberg, K E
    Rosenquist, J B
    Autogenous onlay bone grafts fixed with screw implants for the treatment of severely resorbed maxillae. Radiographic evaluation of preoperative bone dimensions, postoperative bone loss, and changes in soft-tissue profile.1996In: International Journal of Oral and Maxillofacial Surgery, ISSN 0901-5027, E-ISSN 1399-0020, Vol. 25, no 5, p. 351-359Article in journal (Refereed)
    Abstract [en]

    Thirty patients with severely resorbed edentulous maxillae underwent combined treatment of iliac bone onlay graft and titanium implants. The patients were followed for 3 years. They were radiographically examined before surgery to evaluate the bone volume at the intended implant sites. Only 13/156 implant sites were suitable for implant insertion. The bone level at the implant surfaces was evaluated after 6 months and 1, 2, and 3 years, respectively. There was a continuing decrease of the bone level throughout the follow-up period with a mean loss of 4.9 mm after 3 years and with no difference between sexes. Twenty-six implants were radiographically examined before removal, and only three of these implant sites showed radiographic signs of failure. The soft-tissue profile was analyzed cephalometrically by the subtraction technique. The upper lip generally moved inward and the apex of the nose and the columella downward and inward. The anterior facial height increased in most of the patients, resulting in a downward and inward change of the lower lip, the mentolabial sulcus, the soft-tissue pogonion, and the soft-tissue gnathion.

  • 34.
    Nyström, Elisabeth
    et al.
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Surgery.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology.
    Legrell, Per Erik
    Umeå University, Faculty of Medicine, Odontology, Oral and Maxillofacial Radiology.
    Kahnberg, K E
    Bone graft remodelling and implant success rate in the treatment of the severely resorbed maxilla: a 5-year longitudinal study.2002In: International Journal of Oral and Maxillofacial Surgery, ISSN 0901-5027, E-ISSN 1399-0020, Vol. 31, no 2, p. 158-164Article in journal (Refereed)
    Abstract [en]

    A total of 30 patients, 10 in a developmental group and 20 in a routine group, with extremely resorbed maxillae were treated with bone grafting from the hip and implant placement in a one-stage procedure. All patients were followed for a minimum of 5 years and were examined regarding the long-term success rate of the implants and marginal bone level. The implant success rate was 74.6% for the whole patient group and 85.8% for the routine group, after 5 years. The marginal bone along the implant surface decreased continuously, up to 3 years and thereafter the bone level stabilized. In the routine group, changes in bone graft dimensions over time were also evaluated by computerized tomography. The mean height of the bone graft postoperatively at all implant sites was 8.3 mm. The total mean bone height, including bone graft and residual alveolar crest, was 12.4 mm. After 5 years the total bone height had decreased to a mean of 10 mm. The mean width of the bone graft was 12 mm postoperatively and 8.7 mm at the 5-year examination. A substantial amount of bone can be gained in patients with extremely resorbed maxillae, when treated with bone graft according to the procedure described in this study.

  • 35.
    Söderström, Tor
    et al.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Häll, Lars
    Umeå University, Faculty of Social Sciences, Department of Education.
    Nilsson, Tore
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    How does collaborative 3D screen-based computer simulation training influence diagnostic skills of radiographic images and peer communication?2012In: Contemporary Educational Technology, ISSN 1309-517X, Vol. 3, no 4, p. 293-307Article in journal (Refereed)
    Abstract [en]

    This study compares the influence of two learning conditions – a screen-based virtual reality radiology simulator and a conventional PowerPoint slide presentation – that teach radiographic interpretation to dental students working in small collaborative groups. The study focused on how the students communicated and how proficient they became at radiographic interpretation. The sample consisted of 36 participants – 20 women and 16 men – and used a pretest/posttest group design with the participants randomly assigned to either a simulation-training group (SIM) or conventional-training group (CON) with three students in each collaborative group. The proficiency tests administered before and after training assessed interpretations of spatial relations in radiographs using parallax. The training sessions were video-recorded. The results showed that SIM groups exhibited significant development between pretest and posttest results, whereas the CON groups did not. The collaboration in the CON groups involved inclusive peer discussions, thorough interpretations of the images, and extensive use of subject-specific terminology. The SIM group discussions were much more fragmented and included more action proposals based on their actions with the simulator. The different learning conditions produced different results with respect to acquiring understanding of radiographic principles.

  • 36.
    Söderström, Tor
    et al.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Häll, Lars O.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Nilsson, Tore
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Computer Simulation Training in Health Care Education: Fuelling Reflection-in-Action?2015In: Journal Simulation & Gaming, ISSN 1046-8781, E-ISSN 1552-826X, Vol. 45, no 6, p. 805-828Article in journal (Refereed)
    Abstract [en]

    Background Drawing on Donald Schön’s concepts, this article investigates the links between computer simulation training and the concepts of reflection-on-action and reflection-in-action while participating in dental and nursing trainingAim This article explores how collaborative simulation training and collaborative conventional training affect students’ reflection processes when learning to interpret radiographic images.Method This qualitative study uses interviews from 11 nursing and 18 dental students to compare the experiences of conventional training (CON-dental students) with intra-oral radiography simulation (SIM-dental students) and cervical spine simulation training (nursing students).Results The analysis showed that the simulation and conventional training influenced reflective thought processes in different ways. The SIM students concentrated on the visual information before and after they made their choices, whereas the CON students, in the absence of three-dimensional characters and reference points, focused on discussions and mutual agreements within the group to achieve a solution. The visual feedback and opportunities for manipulation provided by the simulation training encouraged the SIM-students to examine their assumptions and actions (to reflect-in-action) while solving the task. Prior knowledge served as a theoretical and methodological scheme guiding the learners’ actions and directed their reflection on their existing anatomical knowledge.Conclusions SIM and CON training provide different conditions for students’ reflective thought processes, and these differences influence how well the groups learn radiological principles.

  • 37.
    Söderström, Tor
    et al.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Häll, Lars Olof
    Umeå University, Faculty of Social Sciences, Department of Education.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Nilsson, Tore
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    How Group Size and Composition Influences the Effectiveness of Collaborative Screen-Based Simulation Training: A Study of Dental and Nursing University Students Learning Radiographic Techniques2012In: World Journal on Educational Technology, ISSN 1309-1506, E-ISSN 1309-0348, Vol. 4, no 3, p. 180-193Article in journal (Refereed)
    Abstract [en]

    This study analyses how changes in the design of screen-based computer simulation training influence the collaborative training process. Specifically, this study examine how the size of a group and a group’s composition influence the way these tools are used. One case study consisted of 18+18 dental students randomized into either collaborative 3D simulation training or conventional collaborative training. The students worked in groups of three. The other case consisted of 12 nursing students working in pairs (partners determined by the students) with a 3D simulator. The results showed that simulation training encouraged different types of dialogue compared to conventional training and that the communication patterns were enhanced in the nursing students ́ dyadic simulation training. The concrete changes concerning group size and the composition of the group influenced the nursing students’ engagement with the learning environment and consequently the communication patterns that emerged. These findings suggest that smaller groups will probably be more efficient than larger groups in a free collaboration setting that uses screen-based simulation training.

  • 38.
    Söderström, Tor
    et al.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Häll, Lars-Olof
    Umeå University, Faculty of Social Sciences, Department of Education.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Nilsson, Tore
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Patterns of interaction and dialogue in computer assisted simulation training2012In: Procedia - Social and Behavioral Sciences: vol. 46, 4th World Conference on Educational Sciences (WCES-2012) 2-5 February 2012 Barcelona, Spain / [ed] Gülsün A. Baskan, Fezile Ozdamli, Sezer Kanbul and Deniz Özcan, Elsevier, 2012, p. 2825-2831Conference paper (Refereed)
    Abstract [en]

    The aim with this study was to explore how computer assisted simulation training mediates dialogue and if there is a relationship between group size and the groups´ dialogue patterns. It is based on two cases, one consisted of 18+18 dental students randomized into either collaborative 3D simulation training or conventional collaborative training, performed in triads. The other case consisted of 12 nursing students working in self-made pairs with the 3D simulator. The results showed that simulation training encouraged different dialogue patterns in comparison to the conventional training and that these characteristics were enhanced in the nursing students´ dyadic simulation training.

  • 39.
    Söderström, Tor
    et al.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Häll, Lars-Olof
    Umeå University, Faculty of Social Sciences, Department of Education.
    Nilsson, Tore
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    How does computer based simulator-training impact on group interaction and proficiency development?2008In: Proceedings of ICICte 2008: Readings in Technology and Education, 2008, p. 650-659Conference paper (Refereed)
  • 40. Åstrand, Per
    et al.
    Ahlqvist, Jan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Gunne, Johan
    Umeå University, Faculty of Medicine, Department of Odontology, Prosthetic Dentistry.
    Nilsson, Hans
    Umeå University, Faculty of Medicine, Department of Odontology, Prosthetic Dentistry.
    Implant treatment of patients with edentulous jaws: a 20-year follow-up2008In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 10, no 4, p. 207-217Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Implant-supported prostheses are today often used in rehabilitation of partially or totally edentulous patients. Both patients and the dental profession often regard implant treatment as successful in a life perspective. Therefore, studies with a long-term follow-up are important.

    PURPOSE: The aim was to investigate the outcome of implant treatment with fixed prostheses in edentulous jaws after 20 years, with special reference to survival rate of implants and prostheses and frequency of peri-implantitis.

    MATERIALS AND METHODS: The patient material was a group of patients treated in the early 1980s. The original patient group comprised the first 48 consecutive patients treated with implant-supported prostheses at Umeå University. All patients were edentulous in one or two jaws. The patients had a mean age at the implant insertion of 54.3 years (range 40-74). At the planning of this study 20 years after treatment, 19 of the 48 patients were found to be deceased. Of the 29 patients still alive, 21 patients with altogether 23 implant-supported prostheses could be examined clinically and radiographically. All patients were treated ad modum Brånemark (Nobel Biocare AB, Göteborg, Sweden) with a two-stage surgical procedure. The implants had a turned surface. Abutment connections were performed 3 to 4 months after fixture insertion in the mandible, and after a minimum of 6 months in the maxilla. The prostheses were fabricated with a framework of gold alloy and acrylic artificial teeth.

    RESULTS: The 21 patients (with 23 implant prostheses) examined had at the time of treatment got 123 implants (27 in the upper jaw and 96 in the lower jaw) inserted. Only one of these implants had been lost (about 2 years after loading) giving a survival rate of 99.2%. Very small changes occurred in the marginal bone level. Between the 1 and 20-year examinations, the mean bone loss was 0.53 mm and the mean bone level at the final examination was 2.33 mm below the reference point.

    CONCLUSIONS: This follow-up over two decades of implant-supported prostheses demonstrates a very good prognosis for the treatment performed. The frequencies of peri-implantitis, implant failures, or other complications were very small, and the original treatment concept with a two-stage surgery and a turned surface of the implants will obviously give very good results.

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