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Publications (10 of 57) Show all publications
Trbakovic, A., Toljnic, J., Kumar, V. V. & Thor, A. (2018). 8-11-year follow-up of immediately loaded implants placed in edentulous maxillae with compromised bone volume and poor bone quality: A prospective cohort study.
Open this publication in new window or tab >>8-11-year follow-up of immediately loaded implants placed in edentulous maxillae with compromised bone volume and poor bone quality: A prospective cohort study
2018 (English)In: Article in journal (Refereed) Submitted
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-364439 (URN)
Available from: 2018-10-28 Created: 2018-10-28 Last updated: 2018-10-28
Trbakovic, A., Bongenhielm, U. & Thor, A. (2018). A clinical and radiological long-term follow-up study of narrow diameter implants in the aesthetic area. Clinical Implant Dentistry and Related Research, 20(4), 598-605
Open this publication in new window or tab >>A clinical and radiological long-term follow-up study of narrow diameter implants in the aesthetic area
2018 (English)In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 20, no 4, p. 598-605Article in journal (Refereed) Published
Abstract [en]

Purpose

To study long-term function of narrow diameter implants (NDI:s) and if reduced implant-tooth distance negatively impacts adjacent teeth.

Materials and Methods

A clinical and radiological follow-up of NDI:s replacing maxillary laterals and mandibular incisors was performed. Subjects that received 3.0-3.3 mm-diameter single implants from 3 units in Uppsala and Vasteras, Sweden, between 2002 and 2011 were offered to participate in this retrospective study.

Results

Twenty-seven patients (30 implants) underwent clinical and CBCT examination, mean follow-up time was 63.3 months. On average, the implant-tooth distance was 1.6 mm at the cervical region and 17 implants were placed 1 mm or less to the adjacent root. Additionally, 2 patients (3 implants) underwent clinical examination (I). Twenty-seven patients (36 implants) declined the examination but agreed to an interview (II). At the time of the follow-up, all implants had good function, and implant survival of group I and II together was 97.2%. In both groups, the 2 main patient concerns were discoloration and regression of the buccal gingiva.

Conclusion

Survival of implants is in accordance to standard diameter studies and although most implants were placed very close to the adjacent teeth, no pathologies could be linked to this except aesthetic concerns.

Place, publisher, year, edition, pages
WILEY, 2018
Keywords
cbct imaging, implant survival, long-term survival, narrow implants
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-363062 (URN)10.1111/cid.12627 (DOI)000440988300022 ()29920935 (PubMedID)
Available from: 2018-10-18 Created: 2018-10-18 Last updated: 2018-10-28Bibliographically approved
Trbakovic, A., Hedenqvist, P., Mellgren, T., Ley, C., Hilborn, J., Ossipov, D. A., . . . Thor, A. (2018). A new synthetic granular calcium phosphate compound induces new bone in a sinus lift rabbit model. Journal of Dentistry, 70, 31-39
Open this publication in new window or tab >>A new synthetic granular calcium phosphate compound induces new bone in a sinus lift rabbit model
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2018 (English)In: Journal of Dentistry, ISSN 0300-5712, E-ISSN 1879-176X, Vol. 70, p. 31-39Article in journal (Refereed) Published
Abstract [en]

OBJECTIVES: The aim of this study was to investigate if a synthetic granular calcium phosphate compound (CPC) and a composite bisphosphonate-linked hyaluronic acid-calcium phosphate hydrogel (HABP·CaP) induced similar or more amount of bone as bovine mineral in a modified sinus lift rabbit model.

MATERIAL AND METHODS: Eighteen adult male New Zeeland White rabbits, received randomly one of the two test materials on a random side of the face, and bovine mineral as control on the contralateral side. In a sinus lift, the sinus mucosa was elevated and a titanium mini-implant was placed in the alveolar bone. Augmentation material (CPC, HABP·CaP or bovine bone) was applied in the space around the implant. The rabbits were euthanized three months after surgery and qualitative and histomorphometric evaluation were conducted. Histomorphometric evaluation included three different regions of interest (ROIs) and the bone to implant contact on each installed implant.

RESULTS: Qualitative assessment (p = <.05), histomorphometric evaluations (p = < .01), and implant incorporation (p = <.05) showed that CPC and bovine mineral induced similar amount of bone and more than the HABP·CaP hydrogel.

CONCLUSION: CPC induced similar amount of bone as bovine mineral and both materials induced more bone than HABP·CaP hydrogel.

CLINICAL SIGNIFICANCE: The CPC is suggested as a synthetic alternative for augmentations in the maxillofacial area.

Keywords
Animal experiments, Bone implant interactions, Bone regeneration, Bone substitutes, Ceramic granules
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-341457 (URN)10.1016/j.jdent.2017.12.009 (DOI)000425888900004 ()29258851 (PubMedID)
Available from: 2018-02-09 Created: 2018-02-09 Last updated: 2018-10-28Bibliographically approved
Nedelcu, R., Olsson, P., Nyström, I., Rydén, J. & Thor, A. (2018). Accuracy and precision of 3 intraoral scanners and accuracy of conventional impressions: A novel in vivo analysis method. Journal of Dentistry, 69, 110-118
Open this publication in new window or tab >>Accuracy and precision of 3 intraoral scanners and accuracy of conventional impressions: A novel in vivo analysis method
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2018 (English)In: Journal of Dentistry, ISSN 0300-5712, E-ISSN 1879-176X, Vol. 69, p. 110-118Article in journal (Refereed) Published
Abstract [en]

Objective: To evaluate a novel methodology using industrial scanners as a reference, and assess in vivo accuracy of 3 intraoral scanners (IOS) and conventional impressions. Further, to evaluate IOS precision in vivo.

Methods: Four reference-bodies were bonded to the buccal surfaces of upper premolars and incisors in five subjects. After three reference-scans, ATOS Core 80 (ATOS), subjects were scanned three times with three IOS systems: 3M True Definition (3M), CEREC Omnicam (OMNI) and Trios 3 (TRIOS). One conventional impression (IMPR) was taken, 3M Impregum Penta Soft, and poured models were digitized with laboratory scanner 3shape D1000 (D1000). Best-fit alignment of reference-bodies and 3D Compare Analysis was performed. Precision of ATOS and D1000 was assessed for quantitative evaluation and comparison. Accuracy of IOS and IMPR were analyzed using ATOS as reference. Precision of IOS was evaluated through intra-system comparison.

Results: Precision of ATOS reference scanner (mean 0.6 mu m) and D1000 (mean 0.5 mu m) was high. Pairwise multiple comparisons of reference-bodies located in different tooth positions displayed a statistically significant difference of accuracy between two scanner-groups: 3M and TRIOS, over OMNI (p value range 0.0001 to 0.0006). IMPR did not show any statistically significant difference to IOS. However, deviations of IOS and IMPR were within a similar magnitude. No statistical difference was found for IOS precision.

Conclusion: The methodology can be used for assessing accuracy of IOS and IMPR in vivo in up to five units bilaterally from midline. 3M and TRIOS had a higher accuracy than OMNI. IMPR overlapped both groups. Clinical significance: Intraoral scanners can be used as a replacement for conventional impressions when restoring up to ten units without extended edentulous spans.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2018
Keywords
Digital impression, Intraoral scanner, Polyether impression, Accuracy, Precision, In vivo
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-349829 (URN)10.1016/j.jdent.2017.12.006 (DOI)000425888000014 ()29246490 (PubMedID)
Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2018-05-07Bibliographically approved
Nilsson, J., Nysjö, J., Carlsson, A.-P. & Thor, A. (2018). Comparison analysis of orbital shape and volume in unilateral fractured orbits. Journal of Cranio-Maxillofacial Surgery, 46(3), 381-387
Open this publication in new window or tab >>Comparison analysis of orbital shape and volume in unilateral fractured orbits
2018 (English)In: Journal of Cranio-Maxillofacial Surgery, ISSN 1010-5182, E-ISSN 1878-4119, Vol. 46, no 3, p. 381-387Article in journal (Refereed) Published
Abstract [en]

Facial fractures often result in changes of the orbital volume. These changes can be measured in three-dimensional (3D) computed tomography (CT) scans for preoperative planning and postoperative evaluation. The aim of this study was to analyze the orbital volume and shape before and after surgical treatment of unilateral orbital fractures using semi-automatic image segmentation and registration techniques. The orbital volume in 21 patients was assessed by a semi-automatic model-based segmentation method. The fractured orbit was compared relative to the contralateral orbit. The same procedure was performed for the postoperative evaluation. Two observers performed the segmentation procedure, and the inter- and intraobserver variability was evaluated. The interobserver variability (mean volume difference ± 1.96 SD) was −0.6 ± 1.0 ml in the first trial and 0.7 ± 0.8 ml in the second trial. The intra-observer variability was −0.2 ± 0.7 ml for the first observer and 1.1 ± 0.9 ml for the second observer. The average volume overlap (Dice similarity coefficient) between the fractured and contralateral side increased after surgery, while the mean and maximum surface distance decreased, indicating that the surgery contributed to a re-establishment of size and shape. In conclusion, our study shows that the semi-automatic segmentation method has precision for detecting volume differences down to 1.0 ml. The combination of semi-automatic segmentation and 3D shape analysis provides a powerful tool for planning and evaluating treatment of orbital fractures.

National Category
Surgery Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-341456 (URN)10.1016/j.jcms.2017.12.012 (DOI)000425712500002 ()29325886 (PubMedID)
Available from: 2017-12-21 Created: 2018-02-09 Last updated: 2018-05-03Bibliographically approved
Nedelcu, R., Olsson, P., Nyström, I. & Thor, A. (2018). Finish line distinctness and accuracy in 7 intraoral scanners versus conventional impression: an in vitro descriptive comparison. BMC Oral Health, 18, Article ID 27.
Open this publication in new window or tab >>Finish line distinctness and accuracy in 7 intraoral scanners versus conventional impression: an in vitro descriptive comparison
2018 (English)In: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 18, article id 27Article in journal (Refereed) Published
National Category
Surgery Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-348983 (URN)10.1186/s12903-018-0489-3 (DOI)000426323900001 ()29471825 (PubMedID)
Available from: 2018-02-23 Created: 2018-04-26 Last updated: 2018-04-27Bibliographically approved
Toljanic, J. A., Ekstrand, K., Baer, R. A. & Thor, A. (2018). Immediate Loading of Tilted and Axial Posterior Implants in the Edentulous Maxillary Arch: A Retrospective Comparison of 5-Year Outcomes. International Journal of Oral & Maxillofacial Implants, 33(2), 433-438
Open this publication in new window or tab >>Immediate Loading of Tilted and Axial Posterior Implants in the Edentulous Maxillary Arch: A Retrospective Comparison of 5-Year Outcomes
2018 (English)In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 33, no 2, p. 433-438Article in journal (Refereed) Published
Abstract [en]

Purpose: The purpose of this study was to retrospectively compare long-term outcomes for immediately loaded tilted and axial implants placed in the posterior region of the edentulous maxillary arch.

Materials and Methods: Data obtained from a 5-year prospective study designed to assess clinical outcomes following immediate loading of implants with screw-retained fixed restorations in the edentulous maxillary arch were retrospectively reviewed. Where insufficient alveolar bone was available for axial placement of the posterior-most implant on each side of the arch, tilted placement was employed. Implant survival and marginal bone level changes for these tilted and axial posterior implants were compared.

Results: Fifty-one subjects received 64 tilted and 38 axial posterior implants. Forty subjects with 53 tilted and 34 axial posterior implants returned for follow-up after 5 years. Five tilted and seven axial implants failed, representing an 89% and 86% survival proportion, respectively. The mean marginal bone loss was 0.79 (SD: 1.42) mm for tilted implants and 0.14 (SD: 0.34) mm for axial implants. The differences in survival proportions and marginal bone loss between axial and tilted implants were not statistically significant.

Conclusion: Predictable long-term implant rehabilitation may be achieved in the edentulous maxillary arch using posterior tilted implants in combination with immediate loading.

Place, publisher, year, edition, pages
QUINTESSENCE PUBLISHING CO INC, 2018
Keywords
dental arch, dental implants, immediate dental implant loading, maxilla
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-350879 (URN)10.11607/jomi.6107 (DOI)000427282400025 ()29534132 (PubMedID)
Available from: 2018-05-23 Created: 2018-05-23 Last updated: 2018-05-25Bibliographically approved
Lewin, S., Riben, C., Thor, A. & Öhman-Mägi, C. (2018). Quantification of radiological changes around dental implants: a CBCT image analysis workflow. In: : . Paper presented at The 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and the 3rd Conference on Imaging and Visualization.
Open this publication in new window or tab >>Quantification of radiological changes around dental implants: a CBCT image analysis workflow
2018 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Engineering and Technology Medical Materials
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-368398 (URN)
Conference
The 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and the 3rd Conference on Imaging and Visualization
Available from: 2018-12-04 Created: 2018-12-04 Last updated: 2018-12-11
Jabbari, F., Wiklander, L., Reiser, E., Thor, A., Hakelius, M. & Nowinski, D. (2018). Secondary Alveolar Bone Grafting in Patients Born With Unilateral Cleft Lip and Palate: A 20-Year Follow-up. The Cleft Palate-Craniofacial Journal, 55(2), 173-179
Open this publication in new window or tab >>Secondary Alveolar Bone Grafting in Patients Born With Unilateral Cleft Lip and Palate: A 20-Year Follow-up
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2018 (English)In: The Cleft Palate-Craniofacial Journal, ISSN 1055-6656, E-ISSN 1545-1569, Vol. 55, no 2, p. 173-179Article in journal (Refereed) Published
Abstract [en]

Objective: To identify factors of oral health important for the final outcome, after secondary alveolar bone grafting in patients born with unilateral cleft lip and palate and compare occlusal radiographs with cone beam computed tomography (CBCT) in assessment of alveolar bone height. Design: Observational follow-up study. Setting: Cleft Lip and Palate Team, Craniofacial Center, Uppsala University Hospital, Sweden. Patients: 40 nonsyndromic, Caucasian patients with unilateral complete cleft lip and palate. Interventions: Clinical examination, CBCT, and occlusal radiographs. Main Outcome Measurements: Alveolar bone height was evaluated according to Bergland index at a 20-year follow-up. Results: The alveolar bone height in the cleft area was significantly reduced compared to a previously reported 10-year follow-up in the same cohort by total (P = .045) and by subgroup with dental restoration (P = .0078). This was positively correlated with the gingival bleeding index (GBI) (r = 0.51, P = .0008) and presence of dental restorations in the cleft area (r = 0.45, P = .0170). There was no difference in the Bergland index generated from scoring the alveolar bone height on occlusal radiographs as with the equivalent index on CBCT. Conclusion: Patients rehabilitated with complex dental restoration seems to be at higher risk for progression of bone loss in the cleft area. Supportive periodontal therapy should be implemented after complex dental restorations in cleft patients. Conventional occlusal radiographs provide an adequate image for evaluating postoperative bone height in clinical follow-up.

Keywords
alveolar bone grafting, dental restoration, unilateral cleft lip and palate
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-348925 (URN)10.1177/1055665617726999 (DOI)000426011700003 ()29351042 (PubMedID)
Available from: 2018-04-26 Created: 2018-04-26 Last updated: 2018-04-26Bibliographically approved
Blache, L., Nysjö, F., Malmberg, F., Thor, A., Rodriguez-Lorenzo, A. & Nyström, I. (2018). SoftCut: A Virtual Planning Tool for Soft Tissue Resection on CT Images. In: Mark Nixon, Sasan Mahmoodi, and Reyer Zwiggelaar (Ed.), Medical Image Understanding and Analysis: . Paper presented at 22nd Medical Image Understanding and Analysis (MIUA) 2018 (pp. 299-310). Cham: Springer, 894
Open this publication in new window or tab >>SoftCut: A Virtual Planning Tool for Soft Tissue Resection on CT Images
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2018 (English)In: Medical Image Understanding and Analysis / [ed] Mark Nixon, Sasan Mahmoodi, and Reyer Zwiggelaar, Cham: Springer, 2018, Vol. 894, p. 299-310Conference paper, Published paper (Refereed)
Abstract [en]

With the increasing use of three-dimensional (3D) models and Computer Aided Design (CAD) in the medical domain, virtual surgical planning is now frequently used. Most of the current solutions focus on bone surgical operations. However, for head and neck oncologic resection, soft tissue ablation and reconstruction are common operations. In this paper, we propose a method to provide a fast and efficient estimation of shape and dimensions of soft tissue resections. Our approach takes advantage of a simple sketch-based interface which allows the user to paint the contour of the resection on a patient specific 3D model reconstructed from a computed tomography (CT) scan. The volume is then virtually cut and carved following this pattern. From the outline of the resection defined on the skin surface as a closed curve, we can identify which areas of the skin are inside or outside this shape. We then use distance transforms to identify the soft tissue voxels which are closer from the inside of this shape. Thus, we can propagate the shape of the resection inside the soft tissue layers of the volume. We demonstrate the usefulness of the method on patient specific CT data.

Place, publisher, year, edition, pages
Cham: Springer, 2018
Series
Communications in Computer and Information Science
National Category
Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-364351 (URN)10.1007/978-3-319-95921-4_28 (DOI)978-3-319-95920-7 (ISBN)
Conference
22nd Medical Image Understanding and Analysis (MIUA) 2018
Available from: 2018-10-25 Created: 2018-10-25 Last updated: 2018-10-25
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9590-2039

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