University of Babylon



Lec: Treatment of class I malocclusion286639083883500Class I occlusion can be defined by Angles, classification as the mesiobuccal cusp of the upper 1st permanent molar occlude with the developmental groove of the lower 1st molar. According to certain criteria, class I occlusion can be subdivided into:1))Normal class I occlusion: Meaning the molar relation is class I and there is no tilted and/or malposed tooth or teeth. Also the antero-posterior occlusal relationship is (normal) class I and there is normal overbite and overjet. Moreover, there is normal transverse as well as vertical relationship between the archs, adding to that the lower incisor,s edges occlude at the (cingulum) middle third of the palatal surface of the upper incisors and the upper canine located between the lower canine and 1st permanent premolar.2)) Class I malocclusion: here the molar relation, similar to the 1st type, also is class I (the antero-posterior occlusal relationship is normal) but there is a discrepancy either within the arches and/or in the transverse or vertical relationship between the arches.289877542926000Crowding and irregularities of teeth. Spacing of teeth.Localized malposition.Discrepancy in the transverse relation (crossbite).Increase overbite and anterior openbite.Aims of class I malocclusion treatment:To improve esthetic of the patient.To improve function of the teeth and the jaw.To improve good oral hygiene and subsequently less carious lesion.3398520-889000Etiology of class I malocclusionSkeletal factor. (usually Class I)Soft tissue factor. (favourable)Dental factor. (main aetiological influences) Treatment of class I malocclusion:1))) crowding and irregularities of teeth: It is associated with increased tooth size and decrease in arch length (hereditary cause), but can also associated with premature loss or delay shedding of the predecessor teeth which later on will lead to tilting; displacement or drifting of teeth into space created (environmental cause).185488937782crowding020000crowdingTreatment of crowding usually is depend on the: 3420110952500Site of the Degree of thePosition of theThe common site of crowding in the upper arch:Lateral incisors which crowded labially or palatally.Canines which is either buccaly or palatally displaced.2nd premolars crowded palatally.2nd and 3rd molars may be buccally displaced.The common site of crowding in the lower arch:Lateral incisors mostly are crowded lingually.Canines buccaly crowded.2nd premolars lingually crowded.2nd and 3rd molars may be displaced mesioangular or impacted.Treatment of crowding: In growing subject, spontaneous relief of crowding after the extraction of deciduous dentition neighboring to the displaced tooth like in case of upper and lower incisors crowding by extraction of the primary canines and spontaneous improvement occurs in the 1st six months after the extraction. If not occurs; otherwise, after 1 year active tooth movement by removable or fixed orthodontic appliances. Or we can relief the crowding by creation of space by any method of space creation according to the degree of crowding, which are: Interproximal strippingArch expansionMolar distalizationProclination of incisorsExtractionAll of the above314388565976500In case of buccally or palatally displced canine by the extraction of upper or lower 1st premolar according to the position of the canine in the arch and use either fixed or removable appliance. While in case of 2nd premolar crowding, by alignment into the arch if its mildly displaced or by extraction of 1st premolar (if it is badly carious) using active orthodontic appliances; otherwise, specially if the 2nd premolar is completely excluded from the dental arch, by extraction of it. Clinical note: extraction of teeth in very mild crowding may result in residual spacing of the arches unless fixed appliances can be used for tooth movement. In more sever crowding, however, spontaneous space closure may be beneficial but may not allow relief of irregularity without the use of passive or active appliances. Whether adequate spontaneous movement occurs will depend on the position of individual teeth particularly their apical position and rotation.3350895134937500 The simple irregularities of the upper arch can be treated with removable appliances, malposition of teeth requiring apical or bodily (controlled) movement needs to be carried out with fixed appliances. While special attention should be given in treatment of lower arch crowding since removable appliances are generally less satisfactory in the lower arch and we have to plan treatment in the lower arch 1st then build the upper arch accordingly. Late lower incisor crowding:In most individuals intercanine width increases up to around 12 to 13 years of age, and this is followed by a very gradual diminution throughout adult life. This reduction in intercanine width results in an increase of any pre-existing lower labial crowding.The aetiology of late lower incisor crowding is recognized as being multifactorial:Forward growth of the mandible when maxillary growth has slowed, together with soft tissue pressures, which result in a reduction in lower arch perimeter and labial segment crowding. Soft tissue maturation.Mesial migration of the posterior teeth owing to forces of occlusion. The presence of an erupting third molar pushes the dentition anteriorly, i.e. the third molar plays an active role.2))) Spacing of teeth: 3506638334393Generalized spacing: Generalized spacing is rare and is due to either hypodontia or small teeth in well-developed arches. Orthodontic management of generalized spacing is frequently difficult as there is usually a tendency for the spaces to re-open unless permanently retained. In milder cases it may be wiser to encourage the patient to accept the spacing, or if the teeth are narrower than average, acid-etch composite additions or porcelain veneers can be used to widen them and thus improve aesthetics. In severe cases of hypodontia a combined orthodontic–restorative approach to localize a space for the provision of prostheses, or implants, may be required.Localized spacing: May be due to hypodontia (mild, moderate, sever); or loss of a tooth as a result of trauma; or because extraction was indicated because of displacement, morphology, or pathology. Whatever the reason for their absence, there are two treatment options:? closure of the space (and camouflage the adjacent teeth).? opening of the space and placement of a fixed or removable prosthesis The choice for a particular patient will depend upon a number of factors:? Skeletal relationship.? Presence of crowding or spacing.? Colour and form of adjacent teeth.? The inclination of adjacent teeth.? The patient’s wishes and ability to co-operate with complex treatment.? The desired buccal segment occlusion at the end of treatment. 332486088138000Diastema: A median diastema is a space between the central incisors, which is more common in the upper arch. A diastema is a normal physiological stage in the early mixed dentition when the fraenal attachment passes between the upper central incisors to attach to the incisive papilla. Before eruption of the permanent canines intervention is only necessary if the diastema is greater than 3 mm and there is a lack of space for the lateral incisors to erupt. After eruption of the permanent canines space closure is usually straightforward. Fixed appliances and Frenectomy if necessary (before, during, after)are required to achieve uprighting of the incisors after space closure. Prolonged retention is usually necessary as diastemas exhibit a great tendency to re-open, particularly if there is a familial tendency, the upper arch is spaced or the initial diastema was greater than 2 mm. Fixed appliance+. 3))) Localized malposition: Diverse contributing factors could be result in the development of tooth displacement. It can be occurs as a result of abnormal position of the tooth germ: canines and 2nd premolars are the most commonly affected teeth or as a result of crowding (lack of space): Appear to affect those teeth that erupt last in a segment? Treatment depend on the general state of the dental arch whether it is crowded or spaced and the etiological factor. 364045517780004))) Crossbite: It is a discrepancy in the transverse (buccolingual ) relationship between the arches. It described in terms of the position of the lower teeth relative to the upper teeth. It can be unilateral or bilateral crossbite which can be corrected by arch expansion using either removable or fixed appliance (hyrex) to open the midpalatal suture.5))) Increased overbite (deepbite): It is a discrepancy in the verical relationship of the dental arches which is mostly associated with reduction in the vertical dimension. It have different types according to the bite depth and gingival trauma. It can be corrected by using simple anterior bite planes (removable appliance) to disclude buccal segment teeth and encourage their overeruption subsequently. While in case of incisors, angulation needs to be corrected to achieve optimal interincisal angle, a fixed appliance is required to produce torquing movement.6))) Open bite:364426565722500 Most of the openbite cases resulted from bad habit are resolved spontaneously as the habit stop during the early stages of growth, otherwise it can persist to adult time. However, when vertical movement of the incisors and/or molars is required, Fixed appliance is the best choice in most cases.Bimaxillary proclination Bimaxillary proclination is the term used to describe occlusions where both the upper and lower incisors are proclined. Bimaxillary proclination is seen more commonly (considered normal) in some racial groups (Negroid). It is Mostly associated with class I malocclusion (i.e. the incisor relation is class I). As aresult, the overjet is increased due to the angulation of the incisors. Also it is mostly associated with lip (seperation, strain, protrusion). The treatment is very difficult due to the action of the tongue and it give a high risk of relapse ( poor prognosis) unless prolong retention is required. It is necessary to treat such malocclusion by a specialist and the patient have a good muscle tone with competent lips which likely to retain the corrected incisor position after the appliance removal.Post treatment retention:318544920139100 Relapse encompasses the return following treatment of the original features of the malocclusion as well as long-term growth and soft tissue changes.This depend on:Severity of the case. Type of tooth movement.Type of treatment.Types of retention: 1)) Removable retention. 2)) Fixed retention. ................
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