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| 2. |
- Lund, Henrik, 1975, et al.
(författare)
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Apical root resorption during orthodontic treatment: A prospective study using cone beam CT
- 2012
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Ingår i: The Angle Orthodontist. - : The Angle Orthodontist (EH Angle Education & Research Foundation). - 0003-3219 .- 1945-7103. ; 82:3, s. 480-487
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Objective: To investigate the incidence and severity of root resorption during orthodontic treatment by means of cone beam computed tomography (CBCT) and to explore factors affecting orthodontically induced inflammatory root resorption (OIIRR). Materials and Methods: CBCT examinations were performed on 152 patients with Class I malocclusion. All roots from incisors to first molars were assessed on two or three occasions. Results: At treatment end, 94% of patients had ≥1 root with shortening >1 mm, and 6.6% had ≥1 tooth where it exceeded 4 mm. Among teeth, 56.3% of upper lateral incisors had root shortening >1 mm. Of upper incisors and the palatal root of upper premolars, 2.6% showed root shortenings >4 mm. Slanted surface resorptions of buccal and palatal surfaces were found in 15.1% of upper central and 11.5% of lateral incisors. Monthly root shortening was greater after 6-month control than before. Upper jaw teeth and anterior teeth were significantly associated with the degree of root shortening. Gender, root length at baseline, and treatment duration were not. Conclusion: Practically all patients and up to 91% of all teeth showed some degree of root shortening, but few patients and teeth had root shortenings >4 mm. Slanted root resorption was found on root surfaces that could be evaluated only by a tomographic technique. A CBCT technique can provide more valid and accurate information about root resorption.
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| 3. |
- Lund, Henrik, 1975, et al.
(författare)
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Cone beam computed tomography evaluations of marginal alveolar bone before and after orthodontic treatment combined with premolar extractions
- 2012
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Ingår i: European Journal of Oral Sciences. - : Wiley. - 0909-8836. ; 120:3, s. 201-211
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Tidskriftsartikel (refereegranskat)abstract
- Using cone beam computed tomography (CBCT) we investigated the distance between the cementoenamel junction (CEJ) and the marginal bone crest (MBC) at buccal, lingual, mesial, and distal surfaces of incisors to first molars in adolescents before (baseline) and after extractive orthodontic treatment (study end point). Patients with Class I malocclusion, crowding and an overjet of =5mm were examined with a CBCT unit using a 60x60-mm field of view and a 0.125-mm voxel size. Large differences in marginal bone height were found at baseline, particularly between tooth surfaces. There was a slight correlation between age and CEJMBC distance. From baseline to the study end point, large bone-height changes among teeth and tooth surfaces could be seen. Lingual surfaces, followed by buccal surfaces, showed the largest changes. Eighty-four per cent of lingual surfaces of mandibular central incisors exhibited a bone-height decrease of >2 similar to mm. The bone-height decrease was larger at lingual surfaces in the mandible than in the maxilla, and larger in girls (mean=1.8mm) than in boys (mean=1.5mm). Fewer than 1% of proximal surfaces exhibited changes of >2mm. It is unknown whether the changes in marginal bone height are transitory. A high-quality CBCT technique may help to determine this by providing a deeper insight into the long-term side effects of orthodontic treatment.
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- Lund, Henrik, 1975, et al.
(författare)
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Cone beam computed tomography for assessment of root length and marginal bone level during orthodontic treatment
- 2010
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Ingår i: Angle Orthodontist. - : The Angle Orthodontist (EH Angle Education & Research Foundation). - 0003-3219 .- 1945-7103. ; 80:3, s. 466-473
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate the accuracy and precision of cone beam computed tomography (CBCT) with regard to measurements of root length and marginal bone level in vitro and in vivo during the course of orthodontic treatment. MATERIALS AND METHODS: Thirteen patients (aged 12-18 years) from an ongoing study and a dry skull were examined with CBCT using multiplanar reformatting for measurements of root length and marginal bone level. For in vivo evaluation of changes in root length, an index according to Malmgren et al was used, along with a modification of this method. RESULTS: The in vitro mean difference between physical and radiographic measurements was 0.05 mm (SD 0.75) for root length and -0.04 mm (SD 0.54) for marginal bone level. In vivo the error was <0.35 mm for root length determinations and <0.40 mm for marginal bone level assessments. CONCLUSION: Despite changes in tooth positions, the CBCT technique yields a high level of reproducibility, enhancing its usefulness in orthodontic research.
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| 5. |
- Lund, Henrik, 1975
(författare)
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Cone Beam Computed Tomography in Evaluations of Some Side Effects of Orthodontic Treatment
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the late 1990s a new imaging modality, Cone Beam CT (CBCT) that enables high quality three-dimensional imaging at lower doses than Computed Tomography (CT), was introduced in dento-maxillofacial imaging. In 2005 the Swedish Council on Health Technology Assessment (SBU), in a review of scientific articles on Malocclusions and Orthodontic Treatment in a Health Perspective, found low or contradictive evidence for an association between orthodontic treatment and risks for negative side effects. It was apparent that some of the issues raised only could be addressed by the use of a radiographic technique enabling three-dimensional imaging with high accuracy and reproducibility. A new medical technology needs to be evaluated before implemented in research. This was the aim of two initial studies that, in vitro, examined the accuracy and precision in CBCT imaging using a Plexglas® object and a dry human skull and, in vivo, assessed its reproducibility in 13 patients. The results showed small differences between actual values and those obtained from measurements in CBCT tomograms and high reproducibility in measurements of root lengths and marginal bone levels. A prospective radiographic study aimed to investigate root resorption and marginal bone level alterations during orthodontic treatment was conducted on 152 adolescent patients with a common type of malocclusion. CBCT examinations were made before (Baseline) and after treatment (Endpoint) and, in a randomly chosen group of 97 patients, six months after treatment initiation. Root lengths, from those of incisors to those of first molars, and the marginal bone height at root surfaces around the teeth were measured in multiplanar reconstructed tomograms. The results showed that 95% of the patients had at least one tooth with a root resorption >1mm. Maxillary lateral incisors and premolars were most often affected and showed the most severe resorptions. Resorptions were also found at buccal and palatal root surfaces, only accessible with a tomographic technique. Jaw, tooth group, and root length at the six-month examination were significantly associated with the degree of root resorption at Endpoint. Before treatment start, large differences in marginal bone height were found, particularly between tooth surfaces. At the end of treatment large changes in bone height among teeth and tooth surfaces could be seen. The largest changes were found at lingual and buccal surfaces, that is, surfaces that cannot be evaluated in conventional radiographs. In contrast, proximal surfaces at posterior teeth, hitherto subjected to most research, showed only small changes. The decrease of marginal bone height was larger in the mandible than in the maxilla and larger in girls than in boys, with respect to palatal/lingual surfaces. A high quality CBCT technique is well suited for research on root resorption and marginal bone level changes during orthodontic treatment as it provides access to anatomic structures that cannot be evaluated in conventional radiographs, high measurement accuracy and precision, and possibilities to reconstruct images to compensate for changes in tooth/root positions that occur during orthodontic treatment.
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| 6. |
- Makedonas, Dimitrios, et al.
(författare)
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Root resorption diagnosed with cone beam computed tomography after 6 months and at the end of orthodontic treatment with fixed appliances
- 2013
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Ingår i: Angle orthodontist. - : The Angle Orthodontist (EH Angle Education & Research Foundation). - 0003-3219 .- 1945-7103. ; 83:3, s. 389-393
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the prevalence of orthodontically induced root resorption after treatment and the correlation with resorption found after 6 months of treatment. Materials and Methods: One hundred fifty-six patients (11-18 years) treated with fixed appliances and extraction of four premolars were examined with cone beam computed tomography before treatment, after 6 months of treatment (n = 97), and at the end of active treatment. The Malmgren Index was used to describe the degree of root resorption. Results: Severe root resorption (>2 mm, score 3) was found in 25.6% of the patients at the end of treatment. Extreme root resorption was found in one patient. Root resorption was seen more frequently in the maxillary incisor region. There was no correlation between the severity of root resorption after 6 months and the amount observed at the end of treatment. Furthermore, no correlation was seen between treatment duration and the severity of root resorption. Conclusions: Clinically significant resorption was diagnosed in 25.6% of the patients, but no correlations, either with the resorption seen after 6 months or with the length of treatment, were found. Radiographic examination after 3 to 6 months of orthodontic treatment is too early and will not reduce the number of patients who will have teeth with severe root resorption.
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| 7. |
- Makedonas, Dimitrios, et al.
(författare)
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Root resorption diagnosed with cone beam computed tomography after 6 months of orthodontic treatment with fixed appliance and the relation to risk factors
- 2012
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Ingår i: The Angle Orthodontist. - : The Angle Orthodontist (EH Angle Education & Research Foundation). - 0003-3219 .- 1945-7103. ; 82:2, s. 196-201
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Objectives: To investigate root resorption after 6 months of active orthodontic treatment and its relation to possible risk factors. Materials and Methods: Ninety-seven patients (10-18 years) with a Class I malocclusion and crowding treated with fixed appliance and premolar extractions were examined with cone beam computed tomography before and after 6 months of active treatment. The exposure covered all teeth from first molar to first molar in both jaws. The Malmgren index was used to evaluate the degree of root resorption. Irregular root contour (score 1) was seen in most teeth already before active treatment, and therefore resorptions were registered only as score 2 (<2 mm, minor resorption) or higher. Results: Minor root resorption was noted in 10% of the patients and severe root resorption, >2 mm (score 3) was found in four patients. Root resorption was more frequently seen in the upper jaw, especially the incisors. There was no statistically significant correlation of root resorption with any of the selected risk factors. Conclusions: After 6 months of treatment, clinically significant resorption was diagnosed in 4% of the patients, ie, in 96% of the patients the radiographic examination did not reveal any significant information. The selected risk factors did not have any impact on the amount of resorption after 6 months of active treatment.
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