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Hellén-Halme, Kristina
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Publications (10 of 53) Show all publications
Cederhag, J., Kadesjö, N., Nilsson, M., Alstergren, P., Shi, X.-Q. & Hellén-Halme, K. (2023). Comparison of absorbed doses and organ doses measured with thermoluminescent dosimeters and Gafchromic film for cone beam computed tomography examination of the posterior mandibular region in a head phantom. Oral surgery, oral medicine, oral pathology and oral radiology, 136(6), 769-776
Open this publication in new window or tab >>Comparison of absorbed doses and organ doses measured with thermoluminescent dosimeters and Gafchromic film for cone beam computed tomography examination of the posterior mandibular region in a head phantom
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2023 (English)In: Oral surgery, oral medicine, oral pathology and oral radiology, ISSN 2212-4403, E-ISSN 2212-4411, Vol. 136, no 6, p. 769-776Article in journal (Refereed) Published
Abstract [en]

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 molar region.

Study design: We positioned TLDs at 75 measurement points in a head phantom. Gafchromic film was cut to the same shape as the 5 levels of the phantom and was placed on top of the TLDs. Both dosimetry methods thus included the surface of each level simultaneously. CBCT scans were made using a 5 × 5 cm field of view and a rotation angle of 200°. Measurements included absorbed dose distributions, doses at all 75 points, and minimum, maximum, and mean doses within organs and tissues.

Results: The correlation of point-dose measurements at all TLD sites with doses measured on film was strong (R2 = 0.9687), with greatest correlation at lower doses (<2 mGy). Large deviations between TLD and film measurements of minimum and maximum doses and absorbed doses to the organs occurred at all 5 levels. TLD positioning failed to cover several organ sites; for these, only absorbed dose measurements from the film were available.

Conclusions: TLDs were unable to sample dose distributions and gradients accurately. The characteristics of Gafchromic LD-V1 film make it a favorable alternative in dental CBCT dosimetry.

Place, publisher, year, edition, pages
Elsevier, 2023
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-62210 (URN)10.1016/j.oooo.2023.07.006 (DOI)001133164600001 ()37625926 (PubMedID)2-s2.0-85168847369 (Scopus ID)
Available from: 2023-08-30 Created: 2023-08-30 Last updated: 2024-02-01Bibliographically approved
Ekstam, M., Sonesson, M. & Hellén-Halme, K. (2023). Effects of premolar extraction and orthodontic treatment in adolescents - a retrospective cephalometric study. Acta Odontologica Scandinavica
Open this publication in new window or tab >>Effects of premolar extraction and orthodontic treatment in adolescents - a retrospective cephalometric study
2023 (English)In: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850Article in journal (Refereed) Epub ahead of print
Abstract [en]

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 patients treated with fixed appliances were retrieved (groups: extraction, n = 19; non-extraction, n = 60). Pre- and post-treatment statuses of skeletal, dentoalveolar, and soft tissue variables were analyzed on lateral cephalograms to determine change. Periapical radiographs of the maxillary incisors were assessed for external apical root resorption using the Levander & Malmgren index. The t-test, Mann-Whitney U test, chi-squared test, and Kruskal-Wallis test were used to analyze the data. Significance was set at p < .05.Results: Changes in the protrusion and proclination of the incisors and in lip position were significantly different between the groups. Prevalence of external apical root resorption in the two groups was similar.Conclusions: Our findings suggest that extraction therapy affects dentoalveolar traits but not jaw position, nor the risk of root resorption, in patients treated with fixed appliances

Place, publisher, year, edition, pages
Taylor & Francis, 2023
Keywords
Cephalometry, extraction treatment, external apical root resorption, malocclusion, orthodontics
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-63500 (URN)10.1080/00016357.2023.2267145 (DOI)001084861300001 ()37830312 (PubMedID)2-s2.0-85174024461 (Scopus ID)
Available from: 2023-11-07 Created: 2023-11-07 Last updated: 2023-11-10Bibliographically approved
Cederhag, J., Iskanderani, D., Alstergren, P., Shi, X.-Q. & Hellén-Halme, K. (2023). Visibility of anatomical landmarks in the region of the mandibular third molar, a comparison between a low-dose and default protocol of CBCT. Acta Odontologica Scandinavica, 81(6), 449-455
Open this publication in new window or tab >>Visibility of anatomical landmarks in the region of the mandibular third molar, a comparison between a low-dose and default protocol of CBCT
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2023 (English)In: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 81, no 6, p. 449-455Article in journal (Refereed) Published
Abstract [en]

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-surgical mandibular third molar investigation were recruited after justification for CBCT. Two CBCT scans of each site were made using a default protocol and a low-dose protocol (Veraviewepocs 3D F40, J Morita Corp, Kyoto, Japan). The low-dose protocol had the same tube potential (90 kV) and exposure time (9.4 s) as the default, but with reduced tube current, from 5 mA to 2 mA. Four observers evaluated the visibility of five relevant anatomical variables. Image quality was ranked on a 3-point scale as diagnostically acceptable, doubtful, or unacceptable. The Wilcoxon signed-rank test compared differences between the two protocols. The significance level was set at p ≤ .05.

RESULTS: No significant differences were found between the two protocols for any observer regarding the visibility of the relationship and proximity between the roots and the mandibular canal; root morphology; and possible root resorption of the second molar. The periodontal ligament differed significantly in visibility between the two protocols (p ≤ .05).

CONCLUSIONS: This study indicates that a low-dose CBCT protocol with a 60% reduction of the tube current provides, in most cases, acceptable image quality for pre-surgical assessment of mandibular third molars. Optimization of CBCT protocols should be a priority according to recommended guidelines.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2023
Keywords
Molar third, cone-beam computed tomography (CBCT), radiation
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-58540 (URN)10.1080/00016357.2023.2170462 (DOI)000928538300001 ()36748228 (PubMedID)2-s2.0-85147663038 (Scopus ID)
Available from: 2023-03-03 Created: 2023-03-03 Last updated: 2023-11-07Bibliographically approved
Vicente, A., Alward, L., Wiedel, A.-P., Becker, M., Shi, X.-Q., Hellén-Halme, K. & Brogårdh-Roth, S. (2022). Do preterm-born children and adolescents have greater need for dental care as compared to full term-born controls?. BMC Oral Health, 22(1), Article ID 479.
Open this publication in new window or tab >>Do preterm-born children and adolescents have greater need for dental care as compared to full term-born controls?
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2022 (English)In: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 22, no 1, article id 479Article in journal (Refereed) Published
Abstract [en]

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 anxiety in paediatric patients. Thus, our aims were to retrospectively compare dental care related examinations and treatments carried out in three different age intervals (3-6 years, 7-12 years, and 13-19 years) among preterm- and full-term born children and adolescents.

METHODS: The present study included 311 patient files: 122 very preterm-born and 33 extremely preterm-born children and adolescents (&lt; 32 gestational weeks). A matched control group of 156 full term-born children and adolescents (≥ 37 gestational weeks) was analysed for comparison. Various factors, including DBMP, missed appointments, dental caries, and radiographic examinations, were retrieved from the dental records for three age intervals: 3-6 years, 7-12 years, and 13-19 years.

RESULTS: Extremely preterm-born children missed significantly more dental appointments and presented with more DBMP during dental examinations and treatment than full term-born children in the 3-6-year age group; the same was observed for the very preterm-born in the 7-12-year age group. No significant differences in DBMP during bitewing and periapical examinations or in number of bitewing, periapical and panoramic radiographs occurred between the groups in any age interval.

CONCLUSION: Preterm-born children and adolescents may need more flexibility in booking and receive reminders for scheduled visits with the general dental team. Due to the non-significant differences in dental care related oral examinations and treatments, the same dental care service may be applied to the preterm- and full-term born children and adolescents.

Place, publisher, year, edition, pages
BioMed Central (BMC), 2022
Keywords
Children, Dental radiography, Intraoral imaging, Preterm birth
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-56098 (URN)10.1186/s12903-022-02504-8 (DOI)000885083600003 ()36352446 (PubMedID)2-s2.0-85141447605 (Scopus ID)
Available from: 2022-11-17 Created: 2022-11-17 Last updated: 2024-02-05Bibliographically approved
Cederhag, J., Truedsson, A., Alstergren, P., Shi, X.-Q. & Hellén-Halme, K. (2022). Radiographic imaging in relation to the mandibular third molar: a survey among oral surgeons in Sweden. Clinical Oral Investigations, 26, 2073-2083
Open this publication in new window or tab >>Radiographic imaging in relation to the mandibular third molar: a survey among oral surgeons in Sweden
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2022 (English)In: Clinical Oral Investigations, ISSN 1432-6981, E-ISSN 1436-3771, Vol. 26, p. 2073-2083Article in journal (Refereed) Published
Abstract [en]

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 = 280) were invited to participate in a web-based digital survey concerning their experiences and use of three imaging modalities in pre-surgical assessment of mandibular third molar removal. The survey comprised multiple-choice questions and four cases depicted in images; respondents reported whether they would supplement the cases with other images and, if so, from which modality.

RESULTS: The response rate was 64%. Panoramic radiographs were most commonly used in pre-surgical planning (response options: always or often), significant difference between professions (p = 0.039), and considered to facilitate treatment planning (87%), as was CBCT (82%); for 51%, CBCT reduced post-operative complications. Preferred modality for localizing the mandibular canal was fairly evenly distributed and for non-complex case, significant difference between subgroups of OMFS surgeons was found (p = 0.003) as to preference for intraoral radiographs.

CONCLUSIONS: A majority of respondents received a report within 2 weeks of their referral for CBCT and would read the report and view the images before surgery. Image modality preference differed depending on case complexity, with a greater perceived need for CBCT. Profession and practical experience affected choice.

CLINICAL RELEVANCE: Choice of imaging modality in mandibular third molar assessment is also important from dose delivery and social economy standpoints.

Place, publisher, year, edition, pages
Springer, 2022
Keywords
Clinical decision-making, Dental radiography, Oral surgical procedures, Third molar, Tooth extraction
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-46362 (URN)10.1007/s00784-021-04189-9 (DOI)000702617400003 ()34596771 (PubMedID)2-s2.0-85116101158 (Scopus ID)
Available from: 2021-10-15 Created: 2021-10-15 Last updated: 2024-02-05Bibliographically approved
Gudac, J., Hellén-Halme, K. & Maciulskiene, V. (2022). The Changes in Size of Periapical Lesions after Root Canal Treatments Assessed by Digital Periapical Radiography and Cone-Beam Computed Tomography: A 2-Years Prospective Clinical Study. Medicina, 58(10), Article ID 1437.
Open this publication in new window or tab >>The Changes in Size of Periapical Lesions after Root Canal Treatments Assessed by Digital Periapical Radiography and Cone-Beam Computed Tomography: A 2-Years Prospective Clinical Study
2022 (English)In: Medicina, ISSN 1010-660X, E-ISSN 1648-9144, Vol. 58, no 10, article id 1437Article in journal (Refereed) Published
Abstract [en]

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 follow-up and to analyse disagreements in periapical lesion size estimates around the same roots using DPR and CBCT. Materials and Methods: A total of 176 endodontically treated teeth, of 128 patients with apical periodontitis, were assessed by DPR and CBCT, at baseline and after 2 years. All periapical radiolucencies were categorised by severity (S0, S1, S2, S3) concerning their size. Descriptive statistics were used to report distribution of the radiolucencies at baseline and at follow-up, and their size transitions over 2 years. Site-specific comparison of the radiolucencies identified by two methods was performed using Z test and Pearson's chi-square test. Results: majority of the detected radiolucencies were scored as S0: 65% and 68% at baseline; 89% and 83% at follow-up, by DPR and CBCT, respectively. Site-specific score comparison showed that disagreements comprised 18% and 20% of the total number of radiolucencies detected by DPR and CBCT, respectively. There were more disagreements between DPR and CBCT within categories S1 and S2 + S3 compared to S0: at baseline, they comprised 17-33% and after two years 62-95% of all detected radiolucencies within the category. 65% of non-matching score transitions over two years occurred between S0 and S1. The CBCT-based evaluation resulted in negative treatment outcomes for 10 more root canals than the DPR-based result. Conclusions: Most remarkable disagreement between DPR and CBCT recordings was observed within the radiolucency categories S2 and S3. However, the diagnostic accuracy of both radiographic methods was questionable as it resulted in a high proportion of non-matching S0-S1 lesion transitions over 2 years.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
apical periodontitis, cone-beam computed tomography, digital periapical radiography, root canal treatment outcome
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-56006 (URN)10.3390/medicina58101437 (DOI)000872984000001 ()36295597 (PubMedID)2-s2.0-85140581188 (Scopus ID)
Available from: 2022-11-15 Created: 2022-11-15 Last updated: 2024-02-05Bibliographically approved
Domic, D., Bertl, K., Ahmad, S., Schropp, L., Hellén-Halme, K. & Stavropoulos, A. (2021). Accuracy of cone beam computed tomography is limited at implant sites with a thin buccal bone: A laboratory study. Journal of Periodontology, 92(4), 592-601
Open this publication in new window or tab >>Accuracy of cone beam computed tomography is limited at implant sites with a thin buccal bone: A laboratory study
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2021 (English)In: Journal of Periodontology, ISSN 0022-3492, E-ISSN 1943-3670, Vol. 92, no 4, p. 592-601Article in journal (Refereed) Published
Abstract [en]

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 implant beds were positioned at a variable distance from the buccal bone surface, thus resulting in 3 BBT groups (i.e., > 0.5-1.0; > 1.0-1.5; > 1.5-2.0 mm). In half of the blocks, a buccal bone dehiscence of random extent ("depth") was created and implants were mounted with different abutment/crown material (i.e., titanium abutments with a metal-ceramic crown and zirconia abutments with an all-ceramic zirconia crown). The distance from the implant shoulder to the buccal bone crest was measured on cross-sectional CBCT images and compared to the direct measurements at the bone blocks.

Results: While abutment/crown material and implant diameter had no effect on the detection accuracy of the buccal bone level at dental implants in CBCT scans, BBT had a significant effect. Specifically, when BBT was ≤ 1.0 mm, a dehiscence was often diagnosed although not present, i.e., the sensitivity was high (95.8%), but the specificity (12.5%) and the detection accuracy (54.2%) were low. Further, the average measurement error of the distance from the implant shoulder to the buccal bone crest was 1.6 mm.

Conclusions: Based on the present laboratory study, BBT has a major impact on the correct diagnosis of the buccal bone level at dental titanium implants in CBCT images; in cases where the buccal bone is ≤ 1 mm thick, detection of the buccal bone level is largely inaccurate. This article is protected by copyright. All rights reserved.

Place, publisher, year, edition, pages
John Wiley & Sons, 2021
Keywords
alveolar process, cone-beam computed tomography, dental implants, titanium, zirconium
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-18158 (URN)10.1002/JPER.20-0222 (DOI)000569443500001 ()32846005 (PubMedID)2-s2.0-85090991592 (Scopus ID)
Available from: 2020-08-31 Created: 2020-08-31 Last updated: 2024-02-05Bibliographically approved
Feng, X., Chen, Y., Cai, W., Lie, S. A., Hellén-Halme, K. & Shi, X.-Q. (2021). Aerodynamic characteristics in upper airways among orthodontic patients and its association with adenoid nasopharyngeal ratios in lateral cephalograms. BMC Medical Imaging, 21(1), Article ID 127.
Open this publication in new window or tab >>Aerodynamic characteristics in upper airways among orthodontic patients and its association with adenoid nasopharyngeal ratios in lateral cephalograms
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2021 (English)In: BMC Medical Imaging, ISSN 1471-2342, E-ISSN 1471-2342, Vol. 21, no 1, article id 127Article in journal (Refereed) Published
Abstract [en]

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) ratios. Methods This retrospective study included thirty-five patients aged 9-15 years having both lateral cephalogram and cone beam computed tomography (CBCT) imaging that covered the UA region. The cases were divided into two subgroups according to the AN ratios measured on the lateral cephalograms: Group 1 with an AN ratio < 0.6 and Group 2 with an AN ratio >= 0.6. Based on the CBCT images, segmented UA models were created and the aerodynamic characteristics at inspiration and expiration were simulated by the CFD method for the two groups. The studied aerodynamic parameters were pressure drop (Delta P), maximum midsagittal velocity (V-ms), maximum wall shear stress (P-ws), and minimum wall static pressure (P-w). Results The maximum V-ms exhibits nearly 30% increases in Group 2 at both inspiration (p = 0.013) and expiration (p = 0.045) compared to Group 1. For the other aerodynamic parameters such as Delta P, the maximum P-ws, and minimum P-w, no significant difference is found between the two groups. Conclusions The maximum V-ms seems to be the most sensitive aerodynamic parameter for the groups of cases. An AN ratio of more than 0.6 measured on a lateral cephalogram may associate with a noticeably increased maximum V-ms, which could assist clinicians in estimating the airflow features in the UA.

Place, publisher, year, edition, pages
BioMed Central, 2021
Keywords
Lateral cephalogram, CBCT, Adenoids, Upper airway, Computational fluid dynamics
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-45820 (URN)10.1186/s12880-021-00659-4 (DOI)000687668900001 ()34425762 (PubMedID)2-s2.0-85113793862 (Scopus ID)
Available from: 2021-09-15 Created: 2021-09-15 Last updated: 2024-02-05Bibliographically approved
Feng, X., Lie, S. A., Hellén-Halme, K. & Shi, X.-Q. (2021). Effect of Rapid Maxillary Expansion on Upper Airway Morphology: A Retrospective Comparison of Normal Patients versus Patients with Enlarged Adenoid Tissue. Journal of Clinical Pediatric Dentistry, 45(3), 208-215
Open this publication in new window or tab >>Effect of Rapid Maxillary Expansion on Upper Airway Morphology: A Retrospective Comparison of Normal Patients versus Patients with Enlarged Adenoid Tissue
2021 (English)In: Journal of Clinical Pediatric Dentistry, ISSN 1053-4628, E-ISSN 1557-5268, Vol. 45, no 3, p. 208-215Article in journal (Refereed) Published
Abstract [en]

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 criteria. We constructed 3D models of the UA on cone-beam computed tomography images to calculate cross-sectional areas and volumes at the levels of the nasopharyngeal, retropalatal, and retroglossal airways. Patients were divided into two groups: group 1 was comprised of patients with an adenoidal nasopharyngeal (AN) ratio < 0.6 and group 2 with an AN ratio >= 0.6. Paired samples t-tests assessed any area and volumetric changes of the UA after RME. Changes in degree of nasal obstruction, calculated as the AN ratio, was then compared for the two groups. An independent samples t-test compared volumetric changes in the nasopharynx between the two groups before and after RME. Results Changes in cross-sectional areas and volumes of the UA due to RME were not significant. The effects of RME on AN ratio (11 % vs 0 %) and nasopharyngeal volume (36.8 % vs 5.97%) were somewhat larger in group 2 patients who had adenoid-associated nasal obstruction compared with group 1 patients with a normal-sized adenoid; however, the differences were not significant. Conclusions After RME, the patients with an enlarged adenoid had more increases in nasopharyngeal volume compared with those with normal adenoid, despite there was no significant difference.

Place, publisher, year, edition, pages
JOURNAL PEDODONTICS INC, 2021
Keywords
Adenoid hypertrophy, Upper airway, Rapid maxillary expansion, 3D
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-44955 (URN)10.17796/1053-4625-45.3.11 (DOI)000669910700011 ()34192749 (PubMedID)2-s2.0-85109181927 (Scopus ID)
Available from: 2021-08-18 Created: 2021-08-18 Last updated: 2024-02-05Bibliographically approved
Iskanderani, D., Nilsson, M., Alstergren, P., Shi, X.-Q. & Hellén-Halme, K. (2021). Evaluation of a low-dose protocol for cone beam computed tomography of the temporomandibular joint [Letter to the editor]. Dento-Maxillo-Facial Radiology, 50(1)
Open this publication in new window or tab >>Evaluation of a low-dose protocol for cone beam computed tomography of the temporomandibular joint
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2021 (English)In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 50, no 1Article in journal, Letter (Other academic) Published
Place, publisher, year, edition, pages
British Institute of Radiology, 2021
National Category
Dentistry
Identifiers
urn:nbn:se:mau:diva-37746 (URN)10.1259/dmfr.20200424 (DOI)000598359100009 ()
Available from: 2021-01-04 Created: 2021-01-04 Last updated: 2022-06-27Bibliographically approved
Projects
Oral health related quality of life, temporomandibular disorders, malocclusions and oral treatment needs in preterm born Swedish children and adolescents; Malmö University
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