| 1. |
- Andrén, Anders, et al.
(författare)
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Pattern and Amount of Change after Orthodontic Correction of Upper Front Teeth 7 Years Postretention.
- 2010
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Ingår i: The Angle Orthodontists. - : The Angle Orthodontist (EH Angle Education & Research Foundation). - 0003-3219 .- 1945-7103. ; 80:4, s. 432-437
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the amount and pattern of changes of maxillary front teeth 7 years postretention, which previously were retained with a bonded retainer. Materials and Methods: The study group consisted of 27 patients. Study models before treatment (T1), at debonding (T2), 1 year after removal of the upper bonded retainer (T3), and 7 years postretention (T4) were present. The irregularity index (sum of contact point displacements) and the rotations of front teeth toward the raphe line were calculated. Results: The irregularity index of the maxillary front teeth changes very little or not at all during the first year postretention. Further change long term resulted in an irregularity index of mean 2.0 (range 0.0–5.8). The contact relationship between the laterals and centrals seems to be the most critical. Forty rotated teeth in 21 patients were corrected more than 20°. Mean relapse during the first year postretention was 6.7° (range 0.0°–14.7°). Mean changes during 7 years was 8.2° (range 0.0°–19.3°). Conclusions: Relapse of upper front teeth retained with a bonded retainer is minor in both the short and long term. If permanent retention is required after 3 years of retention, it is enough to retain the incisors.
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| 2. |
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| 3. |
- Bayat, J. T., et al.
(författare)
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Daily life impact of malocclusion in Swedish adolescents: A grounded theory study
- 2013
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Ingår i: Acta Odontologica Scandinavica. - : Informa UK Limited. - 0001-6357 .- 1502-3850. ; 71:3-4, s. 792-798
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To explore how malocclusions affect daily life in adolescents and how adolescents cope with malocclusion-related distress. Materials and methods. Twelve strategically selected teenagers, seven girls and five boys aged 13-14 years, participated in this study. Open, tape-recorded in-depth interviews based on Focus Group Discussions (FGD) were performed using a theme guide and analyzed according to the qualitative method of classic grounded theory (GT). Results. A core category was identified and named 'Repeatedly reminded of the malocclusion'. Associated to the core category, five categories were generated and labeled 'Being directed by the media's ideal image', 'Monitoring others' teeth', 'Struggling with low self-esteem', 'Hiding one's teeth' and 'Striving for cure'. Low self-esteem appeared to be frequently reinforced through the concerns for the malocclusion and handled via different coping strategies, such as hiding the teeth and striving to receive orthodontic treatment. Such processes were further enforced through the influence of media. Low self-esteem could be associated to a visible malposition of teeth, according to the informants. Having to wait for orthodontic treatment was frustrating the adolescents. Conclusions. Adolescents with malocclusion are often reminded of their condition, which can lead to avoiding strategies to minimize the negative feelings associated with the teeth and low self-esteem. Clinicians may therefore need to be aware of potential irrational behaviors when interacting with adolescents with malocclusions. The findings also suggest that there might be a discrepancy of attitudes between professionals focusing on oral health aspects of malocclusions and the adolescents focusing on esthetic aspects.
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| 4. |
- Bayat, J. T., et al.
(författare)
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Determinants of orthodontic treatment need and demand: a cross-sectional path model study
- 2017
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Ingår i: European Journal of Orthodontics. - : Oxford University Press (OUP). - 0141-5387 .- 1460-2210. ; 39:1, s. 85-91
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To put forward a model predicting orthodontic treatment need and demand. Furthermore, to explore how much of the variance in treatment demand could be explained by a set of self-assessed measures, and how these measures relate to professionally assessed treatment need. Subjects and methods: One hundred and fifty adolescents, aged 13 years, completed a questionnaire which included a set of self-assessed measures dealing with self-esteem, such as dental and global self-esteem, various aspects of malocclusion, such as perceived malocclusion and perceived functional limitation, and treatment demand. Treatment need was assessed by Dental Health Component of the Index of Orthodontic Treatment Need grading. Path analysis was used to examine the relations between the measures and if they could predict treatment need and demand. Results: The measures proved to be reliable and inter-correlated. Path analysis revealed that the proposed model had good fit to the data, providing a test of the unique effect of all included measures on treatment need and demand. The model explained 33% of the variance in treatment demand and 22% of the variance in treatment need. Limitations: The specific age group could affect the generalizability of the findings. Moreover, although showing good fit to data, the final model is based on a combination of theoretical reasoning and semi-explorative approach. Conclusions: The proposed model displays the unique effect of each included measure on treatment need and demand, explaining a large proportion of the variance in perceived treatment demand and professionally assessed treatment need. The model would hopefully lead to improved and more cost-efficient predictions of treatment need and demand.
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| 5. |
- Bayat, J. T., et al.
(författare)
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Predicting orthodontic treatment need: reliability and validity of the Demand for Orthodontic Treatment Questionnaire
- 2017
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Ingår i: European Journal of Orthodontics. - : Oxford University Press (OUP). - 0141-5387 .- 1460-2210. ; 39:3, s. 326-333
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To identify key measures in predicting orthodontic treatment need and to propose a self-assessment instrument that improves treatment need assessment. Subjects and methods: The study included 150 randomly selected 13-year-olds. A set of measures linked to a previous study on daily life impact of malocclusion was processed, resulting in an instrument, the Demand for Orthodontic Treatment Questionnaire (DOTQ), which was analysed regarding dimensionality, reliability and validity. Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC) grading, representing professionally assessed treatment need, were collected from dental records. The instrument's ability to predict treatment need was tested by randomly splitting the dataset into two subgroups, using multiple regression to predict DHC in one of the groups and the prediction equation to calculate predicted DHC in the other. The outcomes were then correlated to detect the predictive power of the DOTQ, and thereby the validity of the prediction. Results: The DOTQ-measures were reliable and highly inter-correlated. A high, significant correlation was found between assessed and predicted treatment need for the subgroups (r = 0.59 and 0.49), confirming the validity of the prediction. Independent variables (the measures) explained 47 per cent (R = 0.69) of the variance in treatment need. Four measures contributed significantly to the prediction, with Treatment Demand being the most powerful predictor. Limitations: The age group and response rate may raise some questions regarding the generalizability of the findings. Conclusions: The DOTQ is able to predict treatment need as assessed by orthodontic consultants. Its incorporation in the treatment need assessment process will acknowledge patients' self-perceived impact of malocclusion.
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| 7. |
- Bergius, Marianne, et al.
(författare)
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Ortodonti i relation till oral funktion
- 2007
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Ingår i: Tandläkartidningen. ; 99:2, s. 52-59
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Forskningsöversikt (populärvet., debatt m.m.)abstract
- The association between the activity of masticatory muscles and craniofacial development has been studied in man as well as in animals. The common finding of these investigations is that the muscles closing the mandible influence the transversal closing the mandible inflkuence the transversal and the vertical dimensions of the craniofacial skeleton. The loading of the facial bones due to masticatory muscle function may stimulate sutural growth and increase bone apposition, leading in turn to an increase of the transversal growth of the maxilla and broader bone bases for the dental arches. The big functional demands of the masticatory muscles are often associated with anterior growth rotation pattern and well-developed angular, coronoid, and condylar processes in the mandible. Individuals with disabilities have an increased prevalence of malocclusion and poor oral function. Behavioural problems and deviating orofacial growth and function will complicate the orthodontic treatment. But with behavioural and various treatment modifications, we can give those patients a well adopted orthodontic treatment. That may favour the facial appearance, achieving a better mouth closure and improve the posibilities to eat and speak. The development and critical evaluation of treatment methods aiming towards normalizing craniofacial and occlusal development is essential. Modified functional appliances such as the ”mandibular repositioning appliance” (MRA) has in placebo controlled studies been shown to reduce periods of respiratory arrest and snoring in patients with mild apnea. This method may also be an alternative in more severe cases where patients do not accept treatment with continous overpressured air (CPAP). Sucessful treatment of sleep apnea must be based on a close cooperation of dentists with knowledge in this field and doctors at sleep apnea clinics. Effects and side effects of treatment must be supervised during long periods.
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| 8. |
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| 9. |
- Cabanettes, Frederic, 1982, et al.
(författare)
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Evaluation of cam and roller surfaces and their manufacturing process by functional characterisation
- 2008
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Ingår i: Proceedings of the Swedish Production Symposium 2008, Stockholm, Sweden. ; , s. 7-
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Konferensbidrag (refereegranskat)abstract
- Friction and wear are constant problems encountered in camshaft development. Thecontact between roller and cam is a mix of sliding and rolling which leads to a wide rangeof failure modes. The uniqueness of this contact is also due to variations all around thecam of a multitude of parameters. A previous study described surface topography as afunction of cam shape. The different types of wear mechanisms are strongly linked tocontact pressures which are also dependent on roughness. The aim of the paper is toevaluate the quality of camshafts and rollers produced with different manufacturinghistories. The evaluation utilises standard roughness parameters as well as rough contactparameters. The surfaces measurements are made by a non-contact light interferometerand a set of 3D roughness parameters is evaluated for each measure. The Greenwood-Williamson contact model has been developed and also applied to the measurements inorder to collect characteristics of the microscopic pressures. The results of the study showthe significant effect of topography variations on the tribological behaviour of the camroller contact and rank the different manufacturing processes according to functionalcharacterization. The verification of the ranking using experiments is the continuity of thisstudy.
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| 10. |
- Cabanettes, Frederic, 1982, et al.
(författare)
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Evaluation of cam and roller surfaces by wear testing and functional characterisation
- 2008
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Ingår i: Proceedings of the 35th Leeds Lyon Symposium on Tribology. ; , s. 8-
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Konferensbidrag (refereegranskat)abstract
- Friction and wear are constant problems encountered in camshaft development. The contact between roller and camis a mix of sliding and rolling which leads to a wide range of failure modes. The uniqueness of this contact is also dueto variations all around the cam of a multitude of parameters such as load and radius. A previous study describedsurface topography as a function of cam shape. The different types of wear mechanisms are strongly linked to contactpressures which are also dependent on roughness. The aim of the paper is to develop a rough contact model which willbe utilized as a tool to rank surfaces and their ability to face wear problems. In order to verify the tool, rough contactresults are compared to roughness parameter variations due to wear produced in a cam roller rig test. The surfacemeasurements used for this study are made by a non-contact light interferometer. The Greenwood-Williamson contactmodel has been developed in a deterministic way and the elasto-plastic behaviour of the material has been integratedto the model. The outputs of the simulation give a ranking of surfaces which is compared to their roughness variationsdue to wear. The study shows that the model developed is a reliable tool to rank and define surface quality since theresults are correlated to wear. However, the results show as well some discrepancies which could be corrected in thefuture by integrating to the model two new features: a rough to rough contact including sliding between surfaces. Thisnew model should be verified by an accurate experimentation using relocation between unworn and worn surfaces.
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