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Nilsson, J., Hindocha, N. & Thor, A. (2020). Time matters - Differences between computer-assisted surgery and conventional planning in cranio-maxillofacial surgery: A systematic review and meta-analysis. Journal of Cranio-Maxillofacial Surgery, 48(2), 132-140
Open this publication in new window or tab >>Time matters - Differences between computer-assisted surgery and conventional planning in cranio-maxillofacial surgery: A systematic review and meta-analysis
2020 (English)In: Journal of Cranio-Maxillofacial Surgery, ISSN 1010-5182, E-ISSN 1878-4119, Vol. 48, no 2, p. 132-140Article, review/survey (Refereed) Published
Abstract [en]

The aim of the study was to assess if there is a time difference (operative time, ischemia time, planning time and hospitalization) between computer-assisted surgery (CAS) and conventional planning in cranio-maxillofacial surgery. An electronic search was performed in June 2018. Studies comparing time difference between CAS and traditional planning were included. 28 publications were included, with 536 patients in the CAS group and 784 in the control group. 18 studies reported on mandibular/maxillary reconstruction and a meta-analysis was conducted on 15 of these studies. This meta-analysis was undertaken to demonstrate the difference between the groups regarding operative time, ischemia time and hospitalization for mandibular/maxillary reconstruction and showed a decreased operative time for the CAS group with a mean difference of -84.61 min, 95% confidence interval [-106.77, -62,45], p <0.001. Ischemia time was also decreased, with a mean difference of -36.14 min, 95% confidence interval [-50.57, -21.71], p < 0.001. This systematic review and meta-analysis suggests that CAS is shortening the operative time and ischemia time for mandibular/maxillary reconstruction. It also leads to a reduction in hospitalization. Additionally, CAS seems to shorten the preoperative planning time for orthognathic surgery.

Keywords
Virtual surgical planning, Computer assisted surgery, Reconstructive surgery, Operative time, Ischemia time, Surgical time
National Category
Surgery
Identifiers
urn:nbn:se:uu:diva-407483 (URN)10.1016/j.jcms.2019.11.024 (DOI)000513969000002 ()31955991 (PubMedID)
Available from: 2020-03-25 Created: 2020-03-25 Last updated: 2020-03-25Bibliographically approved
Temmerman, A., Rasmusson, L., Kübler, A., Thor, A., Merheb, J. & Quirynen, M. (2019). A Prospective, Controlled, Multicenter Study to Evaluate the Clinical Outcome of Implant Treatment in Women with Osteoporosis/Osteopenia: 5-Year Results. Journal of Dental Research, 98(1), 84-90
Open this publication in new window or tab >>A Prospective, Controlled, Multicenter Study to Evaluate the Clinical Outcome of Implant Treatment in Women with Osteoporosis/Osteopenia: 5-Year Results
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2019 (English)In: Journal of Dental Research, ISSN 0022-0345, E-ISSN 1544-0591, Vol. 98, no 1, p. 84-90Article in journal (Refereed) Published
Abstract [en]

The impact of osteoporosis on implant treatment is still a matter of debate in the scientific community, as it may possibly lead to higher failure rates. As long-term controlled trials are missing, the aim of this study was to verify the long-term outcome of implants placed in patients with systemic osteoporosis. Postmenopausal women in need of implants underwent bone mineral density measurements in hip and spine, using dual X-ray absorptiometry scans. Based on T-scores, they were divided into 2 groups: group O (osteoporosis group) with a T-score <=-2 or group C (control group) with a T-score of >=-1. Implants were placed in a 2-stage manner and loaded 4 to 8 wk after abutment surgery. Six months after loading and thereafter yearly, clinical and radiographical parameters were assessed. In total, 148 implants were placed in 48 patients (mean age: 67 y [range, 59-83]). Sixty-three implants were placed in 20 patients (group O) and 85 implants in 28 patients (group C). After 5 y, 117 implants (38 in group O and 79 in the group C) in 37 patients were assessed. Cumulative survival rate on an implant level was 96.5% (group O: 91.5%; group C: 100.0% [P < 0.05]) and 95.7% (group O: 89.2%; group C: 100.0% [P > 0.05]) on a patient level. The overall marginal bone-level alterations, after 5 y of loading, were -0.09 +/- 0.78 mm (group O: -0.15 +/- 0.50 mm; group C: -0.06 +/- 0.89 mm) on an implant level and -0.09 +/- 0.54 mm (group O: -0.18 +/- 0.43 mm; group C: 0.06 +/- 0.58 mm) on a patient level (P > 0.05). Oral implant therapy in osteoporotic patients is a reliable treatment option with comparable osseointegration rates, implant survival, and marginal bone-level alterations after 5 y of functional loading (ClinicalTrials.gov NCT00745121).

Place, publisher, year, edition, pages
SAGE PUBLICATIONS INC, 2019
Keywords
dental implants, marginal bone loss, postmenopausal, long-term outcome, survival rates, bone mineral density
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-373311 (URN)10.1177/0022034518798804 (DOI)000454149700012 ()30205020 (PubMedID)
Available from: 2019-01-16 Created: 2019-01-16 Last updated: 2019-01-16Bibliographically approved
Lewin, S., Riben, C., Thor, A. & Öhman, C. (2019). Bone Volume Assessment Around Dental Implants After Open Maxillary Sinus Elevation Surgery: A Quantitative Approach to CBCT Images. International Journal of Oral & Maxillofacial Implants, 34(2), 489-498, Article ID 30716145.
Open this publication in new window or tab >>Bone Volume Assessment Around Dental Implants After Open Maxillary Sinus Elevation Surgery: A Quantitative Approach to CBCT Images
2019 (English)In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 34, no 2, p. 489-498, article id 30716145Article in journal (Refereed) Published
Abstract [en]

Purpose: Cone beam computed tomography (CBCT) is an important imaging technique in maxillofacial evaluations. However, application-specific image analysis methods aimed at extracting quantitative information from these images need to be further developed. The aim of this study was to provide a robust and objective method that could assess radiologic changes around dental implants after sinus elevation surgery with simultaneous implant placement.

Materials and Methods: The study was performed retrospectively on patients fulfilling the inclusion criteria. The included patients had been CBCT scanned preoperatively, at baseline (early after surgery), and 6 months postoperatively. In order to quantify the radiologic changes, an image analysis workflow was developed based on the postoperative baseline and 6-month scans. The workflow included metal artifact reduction, registration, and a standardized protocol for semiautomatic segmentation. Validation of different steps of the method was conducted by comparing scans from all time points. Comparison of constant volumes (eg, screws and bony parts not subjected to change) was used. Additionally, the Dice similarity coefficient (DSC) was used to measure the overlap of the segmentations.

Results: The study included nine maxillary sinuses from six patients. The bone formation was quantified and visualized in 3D. In the validation, no significant differences were found for the constant volumes at the different scanning time points. The DSC showed accurate results with values > 0.92.

Conclusion: The method presented in this study provides an objective and robust evaluation of bone formation around dental implants. The same methodologies can be applied in other studies of dental CBCT images, eg, for comparison of grafting materials or surgical strategies.

Place, publisher, year, edition, pages
QUINTESSENCE PUBLISHING CO INC, 2019
Keywords
3D, bone volume, cone beam computed tomography, radiology, sinus elevation
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-403242 (URN)10.11607/jomi.7150 (DOI)000506575300023 ()30716145 (PubMedID)
Available from: 2020-01-28 Created: 2020-01-28 Last updated: 2020-01-28Bibliographically approved
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: 2019-12-18Bibliographically 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: 2019-02-25Bibliographically 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: 2019-12-18Bibliographically 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
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ORCID iD: ORCID iD iconorcid.org/0000-0001-9590-2039

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