Introduction to Oral & Dental Anatomy and Morphology 15 Dr Jamal Naim PhD in Orthodontics Introduction to Oral & Dental Anatomy and Morphology 15

Malocclusion

Definition Malocclusion is the deviation from ideal occlusion. J. Naim-Faculty of Dentistry-University of Palestine Definition Malocclusion is the deviation from ideal occlusion. It is the misalignment of teeth or incorrect relation between the teeth of the two dental arches. The term was coined by Edward Angle as a derivative of occlusion.

General Edward Angle was the first to classify malocclusion. J. Naim-Faculty of Dentistry-University of Palestine General Edward Angle was the first to classify malocclusion. He based his classifications on the relative position of the maxillary 1st molar in sagittal relationship to the mandibular 1st molar. The mesiobuccal cusp of the max. first molar should align with the buccal groove of the mandibular first molar.

J. Naim-Faculty of Dentistry-University of Palestine General Any variations from ideal occlusion cause one of the lower listed types of malocclusion: Class I Malocclusion = Neutrocclusion Class II Malocclusion = Distocclusion Class III = Mesiocclusion

Class III Malocclusion J. Naim-Faculty of Dentistry-University of Palestine Class I Malocclusion Class II Malocclusion Class III Malocclusion

Malocclusion

J. Naim-Faculty of Dentistry-University of Palestine Class I Malocclusion By Class I Malocclusion (Neutroocclusion) the molar relationship is normal but the other teeth have problems like spacing, crowding, over or under eruption, etc.

J. Naim-Faculty of Dentistry-University of Palestine Class II Malocclusion A class II malocclusion (or disto- occlusion) is type of malocclusion where the mandibular teeth are in a distal relationship with their normal maxillary opponents A person with class II occlusion may have a mandible that is too small, maxillae that are too large, or both.

J. Naim-Faculty of Dentistry-University of Palestine Class II Malocclusion The result is a mandible that appears behind (retruded from) where it should normally be located.

J. Naim-Faculty of Dentistry-University of Palestine Class II Malocclusion By Class II Malocclusion (Distocclusion) there are two subtypes: Class II Division 1 Class II Division 2 Class II Sub - Division

Class II/1 Malocclusion J. Naim-Faculty of Dentistry-University of Palestine Class II/1 Malocclusion By Class II division 1 the incisors are labial inclined. A severe overjet of maxillary incisors labial to mandibular incisors.

Class II/2 Malocclusion J. Naim-Faculty of Dentistry-University of Palestine Class II/2 Malocclusion By Class II division 2 the centrals are lingual inclined. A severe overbite of maxillary incisors over the mandibular incisors. The lateral teeth are seen overlapping the centrals.

Class II/2 Malocclusion J. Naim-Faculty of Dentistry-University of Palestine Class II/2 Malocclusion

Class II/2 Malocclusion/sub- division J. Naim-Faculty of Dentistry-University of Palestine Class II/2 Malocclusion/sub- division

Class III Malocclusion J. Naim-Faculty of Dentistry-University of Palestine Class III Malocclusion By Class III Malocclusion (Mesiocclusion) the upper molars are placed posteriorly to the mesiobuccal groove. The lower front teeth are more prominent than the upper front teeth. The patient has often a large mandible or a short maxillary bone.

Class III Malocclusion J. Naim-Faculty of Dentistry-University of Palestine Class III Malocclusion

Pseudo Class III Malocclusion J. Naim-Faculty of Dentistry-University of Palestine Pseudo Class III Malocclusion

Class III Sub-division J. Naim-Faculty of Dentistry-University of Palestine Class III Sub-division

J. Naim-Faculty of Dentistry-University of Palestine Dental malocclusions Dental malocclusion of individual teeth can be combined with class I, II, or III relationships. Cross bite

J. Naim-Faculty of Dentistry-University of Palestine Cross bite Cross bite occurs when mandibular teeth are positioned too far buccally or labially so that they overlap the maxillary teeth: Anterior cross bite Posterior cross bite: unilateral or bilateral

J. Naim-Faculty of Dentistry-University of Palestine Posterior cross bite lingual cusps of mandibular teeth are positioned in the central fossae of the maxillary teeth. Normal bite Cross bite

J. Naim-Faculty of Dentistry-University of Palestine Anterior cross bite Mandibular anterior teeth are facial/labial to maxillary anterior teeth.

J. Naim-Faculty of Dentistry-University of Palestine Scissor bite

Midline Shifting

J. Naim-Faculty of Dentistry-University of Palestine Dental malocclusions Dental malocclusion of individual teeth can be combined with class I, II, or III relationships. Open bite

J. Naim-Faculty of Dentistry-University of Palestine Deep bite An anterior overbite is considered to be a severe overbite/deep bite when maxillary incisors overlap mandibular incisors more than 1/3 of their length.

J. Naim-Faculty of Dentistry-University of Palestine Deep bite In severe overbite mandibular incisors may actually impinge upon the tissue of the roof of the mouth (hard palate) and result in an imprint in, or damage to, that tissue.

J. Naim-Faculty of Dentistry-University of Palestine Open bite An Open bite occurs when by centric occlusion opposing teeth do not touch each other. Anterior open bite Posterior open bite

J. Naim-Faculty of Dentistry-University of Palestine Anterior open bite Anterior open bite occurs when the posterior teeth occlude, but there is a space between opposing incisal edges.

J. Naim-Faculty of Dentistry-University of Palestine Posterior open bite Posterior open bite occurs when the anterior teeth occlude, but there is a space between opposing posterior teeth.

Edge-to=edge realationship J. Naim-Faculty of Dentistry-University of Palestine Edge-to=edge realationship If the posterior teeth are in maximum intercuspation and maxillary incisal edges line up touching mandibular incisal edges with no overlap, the result is an edge-to-edge relationship.