Permanent retention from the long-term perspective

Contains fulltext : 120583.pdf (Publisher’s version ) (Open Access)Radboud Universiteit Nijmegen, 13 december 2013Promotores : Katsaros, C., Kuijpers-Jagtman, A.M. Co-promotor : Fudalej, P.S

An Evaluation of Conventional Cephalometric Appraisals

Although lateral cephalographic diagnosis is central to craniofacial skeletal assessment, their classification (categorization) remains largely empiric. In this study, pre- and post-treatment lateral cephalographic dimensional arrays were subjected to the classic numerical taxonomic technique of cluster analysis. The resultant patient groupings (clusters) were not only inconsistent with respect to their Angle malocclusion categories, but also the composition of each cluster group varies depending upon the dimensional arrays analyzed. These findings demonstrate that lateral cephalometric categorization remains largely subjective.Bien que le diagnostic céphalométrique latéral soit essentiel pour l’évaluation du squelette craniofacial, les classifications (catégorisation) restent largement empiriques. Dans le présent travail, les mesures céphalométriques latérales prises avant et après traitement ont été soumises à la technique taxonomique numérique classique de l’analyse de groupe. Les groupes de patients obtenus n’étaient pas compatibles avec leur situation dans la classification des malocclusions d’Angle. De plus, la composition de chaque groupe variait en fonction de l’ordre des dimensions analysées, ces résultats prouvent que la catégorisation céphalométrique latérale reste tout à fait subjective

Ultrastructural changes of collagen and elastin in human gingiva during orthodontic tooth movement

After 15 days of mesializing or distalizing orthodontic treatment, 10 permanent premolars of young patients were extracted with the interdental gingiva. The connective tissues of the compressed or stretched interdental papillae were compared to that of untreated samples by light and transmission electron microscope.Large collagen fibres bundles represented by fibrils with a banding pattern of 64 nm and a mean diameter of 75 nm were observed in compressed interdental gingiva. Several elastic fibres with a mean diameter of 950 nm were also present. In some central areas of compressed gingiva collagen fibrils longitudinally split into widely spaced microfibrils were often observed in proximity to the elastic fibres.In stretched and untreated interdental papillae the collagen fibrils presented a mean diameter of 66 nm and 57 nm respectively. In both groups, few elastic fibres ranging in diameter 600 nm were seen. The increased size of the gingival collagen fibrils undergoing pressure and tension is indicative of remodelling of the fibrous collagen system.The fair increase in number and size of elastic fibres in compressed gingiva suggests that the elastic fibre system takes over the place whenever a collapse of the collagenous framework occurs.Après 15 jours de traitement orthodontique par mésialisation ou distalisation, 10 prémolaires permanentes ont été extraites chez de jeunes patients, ainsi que la gencive interdentaire adjacente. Le tissu conjonctif des papilles interdentaires comprimées ou étirées a été comparé avec celui d’échantillons de dents n’ayant pas subi de traitement. L’observation a été faite en microscopie classique et en microscopie électronique à transmission. Dans la gencive interdentaire comprimée, on observe de longs faisceaux de fibres de collagène faits de fibrilles qui présentent une périodicité de 64 nm et un diamètre inférieur à 75 nm. Ont été observées également de fibres élastiques d’une diamètre inférieur à 950 nm. Dans certaines zones centrales de gencive comprimée, on peut voir, à proximité dess fibres élastiques, des fibrilles de collagène réparties longitudinalement en microfibrilles très espacées.Dans la gencive interdentaire étirée et dans celle non soumise au traitement orthodontique, les fibrilles de collagène présentent un diamètre de 66 nm et 57 nm respectivement. Dans ces deux groupes, on note un très petit nombre de fibres élastiques de 600 nm de diamètre. L’augmentation du nombre et de la taille des fibres élastiques dans la gencive comprimée indique que le système de fibres élastiques remplace la trame collagène qui a subi un collapsus

Comparison of soft tissue changes following orthodontie treatment with two different extraction patterns: Four first premolars vs. four second premolars

The purpose of this study was to compare the soft tissue changes in subjects with orthodontie treatment involving two different extraction patterns: four first premolars or four second premolars. Pretreatment and posttreatment orthodontie treatment records of 81 four premolar extraction patients were obtained and divided into two groups: (PM1) four first premolar extraction group (n= 48) and, (PM2) four second premolar extraction group (n=33). A comparison was made of the changes between the pre- and posttreatment measurements of nasolabial angle (NLA), upper and lower lips to E-plane(mm) using age, sex, upper lip thickness, convexity, and facial axis as variables. Correlation tests were also performed between changes in dental and soft tissue outcomes. The results showed that the NLA increased in both treatment groups indicating a reduction in soft tissue lip protrusion. However, there was no statistically significant difference between the two groups (p=0.99). The average change in lip position between the two groups was not statistically significantly different (p=0.68 and p=0.27 for the upper and lower lip to E-plane, respectively). The upper lip position was strongly correlated with the position of the upper incisor and the lower lip. Conclusion: There was no statistically significant difference between the change in the nasolabial angle or the retraction of the upper and lower lips between four first and four second premolar extraction orthodontie treatments. Furthermore, the change in the nasolabial angle was not significantly correlated with any dental or skeletal changes in either group. Clinically significant difference was found between the groups in some dental and soft tissue outcomes. Extraction pattern alone was not a significant predictor of the changes in soft tissues

Utilisation des plaques d’ancrage en orthodontie

La notion d’ancrage est primordiale lors de l’élaboration d’un plan de traitement orthodontique, car de sa détermination découle l’atteinte des objectifs de fin de traitement. Le développement des plaques d’ancrage en orthodontie, grâce à l’obtention d’un ancrage absolu, a permis d’élargir les possibilités de prise en charge orthodontique. Ces mini-plaques d’ancrage squelettique, notamment utilisées par De Clerck et Sugawara, permettent d’obtenir des mouvements orthodontiques autrefois considérés comme quasi impossibles, repoussant, dans certains cas, les indications de chirurgie orthognatique ou d’avulsions. Bien que l’insertion et la dépose soient plus complexes que celle des minivis, les nombreux avantages liés à leur utilisation, comme une valeur d’ancrage plus importante, en font un allié thérapeutique non négligeable. Les mini-plaques constituent ainsi un système innovant et efficace dans la prise en charge de patients chez lesquels les limites de l’orthodontie classique sont atteintes. Leur utilisation doit toutefois répondre à des indications très précises associées à un rapport bénéfice-risque favorable, chez l’adulte comme chez l’enfant

Non-invasive removal of sandblasted and acid-etched titanium palatal implants, a retrospective study

BACKGROUND Short, rough-surfaced palatal implants are an established and reliable anchor for orthodontic treatment. Until recently, removal was only possible surgically using a hollow cylinder trephine. This standard method retrieves the implant combined with a larger bone volume and is therefore considered invasive and has known complications. Lately, an explantation tool which allows a sufficient force application to break the bone-implant-connection and unscrew the palatal implant was developed and, since its introduction, has been used as the method of choice in several orthodontic offices. OBJECTIVES The aim of this study was to assess the complications caused by removing rough-surfaced palatal implants simply by unscrewing them with an explantation tool in contrast to standard protocol by surgical removal with a trephine. MATERIAL AND METHODS The removal of 73 palatal implants using a customized explantation tool has been evaluated retrospectively and was compared to an existing sample of 44 conventional surgical explantations. RESULTS The new clinical procedure resulted in successful removal of 71 (97.3 per cent) palatal implants. In two cases, the new method failed but removal with the established surgical method was still possible with no further complications. The non-invasive palatal implant removal with a customized explantation tool had less medical complications compared to an existing sample of surgical explantations. CONCLUSIONS User's opinion was that the new method is more easily executed, less invasive, and also applicable without local anaesthesia. Therefore, it is considered to be beneficial for patients and the treatment approach of choice. However, further research is needed for verificatio

Cervical Vertebral Maturation Stage as a Growth Predictor

I would like to express my sincere appreciation to the members of my thesis committee: Dr Stuart Hunter, Dr Antonios Mamandras, Dr Lesley Short, Dr David Banting, Dr John Murray and Dr Brian Tompson. In particular, thank you to my thesis supervisor, Dr Stuart Hunter, for your help and support during my thesis project. You are an inspiration and a role model to me. A special thank to Dr Antonios Mamandras and to Dr Lesley Short for their help and support through the whole program. You made my experience at Western unforgettable. For all the support provided to me in completing this thesis and this program, thank you Barb Merner, Joanne Pfaff, Leesa Couper, Evelyn Larios, PJ Blake, Justina Hovarth, Jackie Geneau and Cynthia Mugimba. You made my experience at Western memorable. I want to say thanks to all of my co-residents: Nadia, Mitch, Dolly, Ali, Mark, Mike, Mariela, Manisha, Neville, Dana, Phil and Julia. Thank you for your comradery, support and humour. To my classmates Ziad and Julia, the past three years have been a true learning experience. Thank you for being such good classmates. I will never forget all the special moments we shared together. Most importantly, I dedicate this thesis to my entire family. To my husband Jalal, thank you for your love, patience and support. Thank you for believing in me and for supporting me in every step of the way. I couldn’t have done it without you. To Mom and Dad, thank you for believing in me every day of my life. Your love and support over the last three years allowed me to follow my dream. I am eternally grateful. To my adorable daughter Mayali, I know we will be able to make up for lost time together but know you are my raison d’être and the sunshine in my life

Retención postortodóncica fija y estética

Hemos efectuado una revisión clínica de 30 casos de retención postortodóncica con férula rígida de resina, de canino a canino en ambas arcadas. Se describe la construcción de la férula, la colocación, los posibles incidentes o problemas clínicos aparecidos (adhesión deficiente, gingivitis ...) y los aspectos psicológicos o subjetivos del paciente