Malocclusion Lecture 4 PDF

 LECTURE 4: MALOCCLUSION DR. MANLANGIT...

 LECTURE 4: MALOCCLUSION DR. MANLANGIT INTRODUCTION NORMAL OVERBITE Malocclusion is a condition, not a disease, which describes the → incisal edge of maxillary tooth within the incisal third of the relationship of the maxillary and mandibular dentitions in relation to facial surface of the mandibular incisor the cranium (skull). EDGE-TO-EDGE BITE Malocclusion is now called an “orthodontic condition”. The new term → incisal surfaces occlude used for diagnosis is “orthodontic assessment”. ANTERIOR CROSSBITE The gold standard of orthodontic treatment is ideal occlusion. → maxillary anterior teeth are lingual to mandibular anterior teeth → occurs in Angle’s Class III malocclusion DEEP (SEVERE) ANTERIOR OVERBITE → incisal edge of the maxillary tooth is at the level of the cervical third of the facial surface of the mandibular anterior tooth OPEN BITE → lack of incisal contact → posterior teeth in normal occlusion END-TO-END BITE → molars in cusp-to-cusp occlusion as viewed from the facial OVERJET → horizontal relationship of anterior teeth → maxillary incisors are labial to the mandibular incisors UNDERJET → maxillary incisors are lingual to the mandibular incisors CROSSBITE → only half of the crown is misaligned → can be an anterior or posterior crossbite → can be unilateral or bilateral BUCCAL SCISSORS CROSSBITE → entire crown is malpositioned → complete buccalversion LINGUAL SCISSORS CROSSBITE Dr. Angle gave one of the best examples of a hypothesis–his “key to → entire crown is lingually displaced occlusion.” → most important teeth are the 1st permanent molars because they are the most constant in their positions Note! → specifically upper 1st permanent molars → retroclined is the opposite of proclined incisors → they are the very cornerstones and thus they became basis for → in cases of a missing tooth, look at the 2nd molar relationships his classification of malocclusion or canines to classify a malocclusion ARCH FORMS LINE OF OCCLUSION (BONWILL) → narrow → curve formed by buccal cusps of mandibular posterior teeth and → parabolic or average incisal edges of mandibular anterior teeth → wide → cannot be seen when maxillary and mandibular teeth are in contact OVERBITE → vertical relationship of anterior teeth Kirsten M. Abarquez | Cebu Doctors’ University | DMD-3B  LECTURE 4: MALOCCLUSION DR. MANLANGIT SMILE ARC → when a person smiles, the curve line following the incisal edges Type I edge to edge anteriors of maxillary teeth Type II crowded mandibular anteriors & they are in crossbite → “esthetic line of dentition” Type III crowded maxillary anteriors & they are in crossbite → the anterior portion of this esthetic line of dentition FACIAL PROFILES Class I straight Class II convex Class III convex concave CLASS I → normal (ideal) occlusion → molar relationship: o mesiobuccal cusp of maxillary first permanent molar occludes with the buccal groove of the mandibular first permanent molar Type I crowded incisors Type II labioverted/protruded maxillary incisors Type III pseudo-class III or anterior crossbite Type IV posterior cross-bite Type V mesial drifting of molars due to premature loss of tooth CLASS II → distoclusion → molar relationship: o buccal groove of the mandibular first permanent molar is distal to the mesiobuccal cusp of the maxillary first permanent molar by at least the width of a premolar Division I all anteriors protruded Division II 1 or more incisors retruded CLASS III → mesioclusion → molar relationship: o buccal groove of the mandibular first permanent molar is mesial to the mesiobuccal cusp of the maxillary first permanent molar by at least the width of a premolar Kirsten M. Abarquez | Cebu Doctors’ University | DMD-3B