Occlusion, Bites, Facial Types, and Profile Types PDF

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Professor Sharron Dierckens ...

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Occlusion, Bites, Facial Types, and Profile Types Facial Types 1. Mesognathic (Orthognathic)-slight jaw protrusion, flat facial outline, straight profile 2. Retrognathic- prominent maxilla, mandible posterior to normal, convex profile 3. Prognathic – prominent mandible, normal maxilla, concave profile Profile Types 1. Straight 2. Concave 3. Convex Frankfort Plane- from upper margin of inner ear opening (meatus) to lower margin of eye orbit

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imaginary line drawn form glabella (anterior of frontal bone) to the menton (tip of chin) if the line is straight up and down= straight profile (lips on line) if line slopes posteriorly= convex profile (lips anterior to line) if the line slopes anteriorly= concave profile (lips posterior to the line)

Crossbite - maxillary teeth positioned lingually to mandibular teeth - mandibular teeth can be lingual to maxillary teeth of mandible is small - anterior or posterior cross bites that can be bilateral or unilateral A. mandibular teeth lingual to normal position B. mandibular teeth facial to normal position C. unilateral cross bite (RS is normal, LS has mandibular teeth facial to normal

Edge to Edge (End to End) Bite - occurs when teeth occlude without maxillary teeth overlapping mandibular teeth - can occur anteriorly or posteriorly, bilaterally or unilaterally - some clinicians use edge to edge to refer to anteriors and end to end for posteriors Open Bite - lack of occlusion of inscisal contact - abnormal vertical space between maxillary and mandibular teeth - can occur anteriorly or posteriorly (mostly anterior) Overbite

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vertical distance where max incisors overlap mand incisors normal overbite is where inscisal edges of maxillary teeth are within inscisal 1/3 of mandibular teeth moderate overbite is where inscisal edges of max teeth are halfway down mandibular teeth severe overbite is where edge of maxillary tooth is at the cervical 1/3 of mandibular tooth

Overjet - horizontal distance between inscisal edge of max incisors and labial surfaces of mand incisors - at SCC use 41 and 11(2 readings taken and averaged if big diff in 41/11 and 31/21) - some clinicians measure from lingual surface of max incisors to labial surface of mand incisors - periodontal probe is used to measure the distance Underjet - max teeth lingual to mand teeth - horizontal distance between labial surface of max incisors and inscisal edges of mand - measurable distance is evident

Labioversion- tooth positioned labial to normal Linguoversion- tooth positioned lingual to normal Buccoversion- tooth positioned buccal to normal Supraversion- tooth is elongated above the line of occlusion (ex. over an erupted tooth) Torsiversion- tooth is turned or rotated Infraversion- tooth positioned below the line of occlusion (ex. primary tooth thats been submerged) Midline Shift - use a piece of floss to measure whether midlines of max and mand cereal incisors line up - have client retried their mandible as far as possible and close on posterior teeth - line floss up with midline, and determine whether it is even - some clinicians use the philtrum as a reference point, and use a probe to check shift - record length and width of face as part of skeletal relationship - length is long , short, or normal - width is broad, narrow, or normal

Occlusion - natural closure and fitting together of the teeth in the mandibular arch to those in max arch - malocclusion is abnormal occlusion of the teeth - centric occlusion is relation of opposing occlusal surfaces that provide most contact or intercuspation - also called habitual occlusion Static Occlusal Relationships - seen when jaws are closed in centric relation - most unstrained, retruded physiologic relation of mandible to maxilla where lateral movements made - static occlusion seen directly in the oral cavity when lips and cheeks are retracted (or on study models) Normal (Ideal) Occlusion- Class I - all teeth of max arch are in maximum contact with all teeth in mand arch in a definite pattern - max teeth slightly overlap mand teeth on facial surfaces - facial profile is mesognathic (orthognathic)

- molar relation= MB cusp of max 1st molar occludes with buccal groove of mand 1st molar - canine relation= max canine occluding with distal 1/2 of mand canine and mesial 1/2 of 1st mand premolar Class I Malocclusion or Neutroclusion

- malpositioning of individual teeth or groups of teeth - facial profile, molar relations, and canine relations are all the same as normal occlusion - common examples are crowded max or mand anteriors, protruded or retruded max incisors, anterior cross bite, posterior cross bite, and mesial drifting of the molars (premature loss of teeth) Class II Distoclusion - occurs when mand teeth are positioned posterior to the normal position in relation to maxillary teeth - profile type is retrognathic (maxilla protrudes and mandible appears retruded or weak) - lower lip is full and often rests between max and mand incisors - buccal groove of mand 1st molar distal to MB cusp of max 1st molar by width of 1+ premolar - when the distance is less than that of a premolar, relation is “class II tendency” Class II Div I- mandible retruded and max incisors protruded Class II Div II- mandible retruded and 1 or more max molars are retruded Class III Mesioclusion - occurs when mandibular teeth are anterior to normal position in relation to max teeth - Profile type is prognathic (lower lip and mandible are prominent) - buccal groove of mand 1st molar is mesial to MB cusp of max 1st molar by width of 1+ premolar - when the distance is less than that of a premolar, relation is “class III tendency” - frequently occurring conditions include… • true Class III is when max incisors are lingual to the mand incisors in anterior cross bite • max and mand arches are edge to edge • mand anteriors are crowded but lingual to max incisors Primary Occlusion - uses distal surfaces of primary max and mand second molars 1. Flush or Straight Terminal Plane - distal surfaces of max and mand 2nd molars align evenly - ideal relationship of that should develop into class I occlusion or class II malocclusion

2. Mesial Step - mand 2nd molar is positioned mesially to distal surfaces of max 2nd molar - should develop into a class I relationship - if present at an early age, mesial step can indicate excessive mandible development - this may develop into a class III in permanent 3. Distal Step - mand 2nd molar distal to distal surface of max 2nd molar - may be a sign of a deficiency in mandible development of mandible - will likely develop into a class II relationship in permanent - least frequent type of primary occlusion...