Summary Objective: The aim of this study was to evaluate the components of over

Summary Objective: The aim of this study was to evaluate the components of overbite correction with the lingual Incognito technique. Materials and methods: The study was based on 45 files of patients with overbite treated with the Incognito technique. The evaluation of overbite correction is assessed by comparing lateral cephalograms before and after treatment using QuickCeph 2000 software. All the statistical calculations were performed using Statview II software for Mac. Results: The results revealed the efficiency of the Incognito technique in overbite correction despite the absence of bite planes in the majority of cases. The components of this correction are, in order: intrusion of mandibular incisors, extrusion of man- dibular molars, weak extrusion of maxillary molars and stabil- ity of the maxillary incisors. These were the results commonly found in previous studies on small samples. The study also demonstrated an increase of lower face height in extraction and non-extraction cases. R esum e Objectifs : Le but de cette  etude  etait d’ evaluer les compo- santes de la correction de la supraclusion en technique lin- guale Incognito. Mat eriels et m ethodes : L’ etude  etait bas ee sur 45 dossiers de patients pr esentant une supraclusion trait es en technique Incognito. L’ evaluation de la correction de la supraclusion a  et e r ealis ee en comparant des t el eradiographies de profil du cr^ ane avant et apr es traitement en utilisant le logiciel QuickCeph 2000. Les calculs statistiques ont  et e effectu es gr^ ace au logiciel Statview II for Mac. R esultats : Les r esultats ont r ev el e l’efficacit e de la technique Incognito dans la correction de la supraclusion en d epit de l’absence de plans de sur el evation (bite-planes) dans la majorit e des cas. Les composantes de la correction sont dans l’ordre : une ingression de l’incisive mandibulaire, une  egression de la molaire mandibulaire, une faible  egression de la molaire maxillaire et une stabilit e de l’incisive maxillaire. Ces r esultats sont conformes a ` ceux trouv es dans des  etudes pr ec edentes sur de faibles  echantillons. Les r esultats ont  egalement montr e une augmentation de la hauteur faciale inf erieure dans les cas avec et sans extractions. Original article Article original  2014 CEO Published by / E ´ dite ´ par Elsevier Masson SAS All rights reserved / Tous droits re ´serve ´s Components of overbite correction in lingual orthodontics: Molar extrusion or incisor intrusion? Composantes de la correction de la supraclusion en technique linguale :  egression molaire ou ingression incisive ? St ephane BARTHELEMIa,*, Marie-Pascale HYPPOLITEb, Chrsitian PALOTc, Dirk WIECHMANNd a8 bis, place de l’Ancien H^ opital, 60200 Compi egne, France bParc de Ballius, 34670 Baillargues, France cFacult e d’odontologie, 2, rue du G en eral-Koenig, 51100 Reims, France dDepartment of Orthodontics Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany Available online: 13 November 2014 / Disponible en ligne : 13 novembre 2014 *Correspondence and reprints / Correspondance et tir es a ` part. e-mail address / Adresse e-mail : steph.barthelemi@wanadoo.fr (St ephane Barthelemi) International Orthodontics 2014 ; 12 : 395-412 395 http://dx.doi.org/10.1016/j.ortho.2014.10.007 Conclusion: The Incognito technique is very efficient in over- bite correction. As the main component of overbite correction is mandibular incisor intrusion, it seems crucial from the esthetic point of view to evaluate the smile line when overbite correction is needed.  2014 CEO. Published by Elsevier Masson SAS. All rights reserved Key-words ·Overbite. ·Lingual technique. ·Extractions. Introduction Incisor overbite is defined as an excess overlap between man- dibular and maxillary incisors of more than 3 to 4 mm [1]. Overbite correction during orthodontic treatment is often tricky, and relapse may occur in some cases. The action of the orthodontic appliance in overbite correction is based on incisor (maxillary and/or mandibular) intrusion and/or molar extrusion [2–6]. Several studies have attempted to quantify these two different approaches [3,4]. Lingual orthodontics is known for its efficient ability to open the bite and to correct overbite. The creation in 1984 of the Kurz bracket with a bite plane marked a revolution in lingual orthodontics and bite opening [7]. In overbite situations, mandibular incisors are in contact with the bite planes, which ungear the lateral occlu- sion and immediately correct the overbite. Since 2002, the Incognito technique has proposed an individualized CAD- CAM bracket which is bonded close to the enamel surface; the bite planes are optional in this technique. One of the specific aspects of the Incognito technique is that the wires are placed ribbonwise and not edgewise [8–10]. Very few studies have focused on the components of overbite correction in orthodontics, and particularly in lingual ortho- dontics. In 1989, Fulmer and Kuftinec [11] showed in their study that overbite correction could be achieved by mandib- ular incisor intrusion. In 1995, Hellsing and Hellsing [12], and later, in 1996, Hellsing et al. [13] demonstrated on a small sample of 8 cases with severe overbite that the bite opening induced by the bite plane was achieved by a 2 to 1 ratio between the incisor and the molar movement, without any change in the position of the condyle in the glenoid fossa. These conclusions were close to those mentioned by the study of Dos Santos and De Rijk [5] in 1995. The authors presented a mathematical model of different bite planes, and demon- strated that, whatever the morphology, bite planes induce anterior positioning of the mandible, and that the forces Conclusion : La technique Incognito s’av ere tr es efficace dans la correction de la supraclusion. La principale compo- sante de la correction de la supraclusion  etant une ingression de l’incisive mandibulaire, il semble essentiel d’un point de vue esth etique d’ evaluer la ligne du sourire lorsqu’une correction de la supraclusion est envisag ee.  2014 CEO. E ´dite ´ par Elsevier Masson SAS. Tous droits re ´serve ´s Mots-cl es ·Supraclusion. ·Technique linguale. ·Extractions. Introduction La supraclusion incisive est d efinie par un exc es du recouvre- ment des incisives mandibulaires par leurs homologues max- illaires de plus de 3 a ` 4 mm [1]. La correction de la supraclu- sion au cours du traitement orthodontique s’av ere souvent d elicate et la r ecidive apparaı ˆt dans certains cas. L’action de l’appareillage orthodontique est bas ee sur l’ingression des incisives (maxillaires et/ou mandibulaires), et/ou l’ egression du secteur molaire [2–6]. Plusieurs  etudes ont tent e de quan- tifier l’efficacit e de ces deux approches, totalement diff erentes sur le plan conceptuel [3,4]. La technique linguale est r eput ee pour son efficacit e a ` ouvrir l’occlusion et corriger la supraclu- sion. En effet, la cr eation en 1984 des attaches de Kurz avec plans de sur el evation (bite-planes) a  et e une r evolution dans la technique linguale et l’ouverture de l’occlusion [7]. En pr esence d’une supraclusion, les incisives mandibulaires butent contre les bite-planes provoquant le d esengr enement lat eral et la correction de la supraclusion [10]. Depuis 2002 la technique Incognito propose une attache r ealis ee par CFAO coll ee le plus pr es possible de la face linguale de la dent ; les bite-planes sont optionnels dans cette technique. Une des sp ecificit es de la technique Incognito est que les arcs sont plac es en ribbonwise et non pas en edgewise[8–10]. Tr es peu d’ etudes traitent des composantes de la correction de la supraclusion en orthodontie en g en eral et en technique linguale en particulier. En 1989, Fulmer et Kuftinec [11] ne notaient qu’une ingression de l’incisive mandibulaire. En 1995, Hellsing et Hellsing [12], puis en 1996 Hellsing et al. [13],  etudiant un petit  echantillon de 8 cas pr esentant une forte supraclusion ont montr e que l’ouverture de l’occlusion provoqu ee par le contact sur le plan de morsure des attaches se faisait selon un ratio d’environ 2 a ` 1 entre mouvement incisif et mouvement molaire, sans changement de la position du condyle dans la fosse mandibulaire. Ces conclusions sont a ` rapprocher de celles qui sont  emises en 1995 par Dos Santos et De Rijk [5] : ces auteurs ont pr esent e un mod ele math ematique des effets de diff erents plans de sur el evation et ont montr e que quelle que soit sa conception, un plan de 396 International Orthodontics 2014 ; 12 : 395-412 St ephane BARTHELEMI et al. generated on the temporomandibular joint are approximately proportional to the degree of elevation. Hence, it seems rele- vant to study the mechanisms of overbite correction with the Incognito technique, as bite planes are optional and seldom used. All previous studies were conducted on a limited number of cases in which the “statistical truth” is not demonstrated. The aim of this study was to evaluate the efficiency of overbite correction using the Incognito technique, and including a larger number of cases (45) based on cephalometric evaluation. Materials and methods uploads/Ingenierie_Lourd/ barthelemi2014.pdf

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