Exam Functional Anat PDF

Chapter 6 Occlusion What affects the alignment of teeth? Also affected by eruption patterns, facial development, absence of diastema, leeway spaces and mesial drift What muscle forces affect teeth alignment? Horizontal alignment of teeth is affected by the balance of forces from the tongue pushing...

Chapter 6 Occlusion What affects the alignment of teeth? Also affected by eruption patterns, facial development, absence of diastema, leeway spaces and mesial drift What muscle forces affect teeth alignment? Horizontal alignment of teeth is affected by the balance of forces from the tongue pushing the teeth out of the mouth. Along with the cheek and lips holding the teeth in. What is the difference between curve of spee and a flat-planed occlusion? Slight curve of spee is seen in most normal occlusions. Curve is higher in the anterior and posterior and dips in the middle. The curve allows for more room for eruption of the teeth. Flat plane would not allow as much room for teeth. Open bite: When anterior teeth do not touch but are widely separated when in centric occlusion. Open contact between the arches. Overbite: Extension of the incisal edges of the maxillary anterior teeth below the incisal edges of the mandibular anterior teeth. Average in kids is 2.5mm Overjet: Amount of facial horizontal overlap of the max teeth over the man teeth. Average in kids 3mm Centric occlusion: Position when jaws are closed teeth are in max intercuspation Class 2 canine relationship occurs when the man canine’s distal is distal to the max canine by one premolar width. What is mesial step? Perm man first molar is mesial to the perm max first molar Which factors influence occlusion? Hereditary, unrestored baby teeth, decayed molars, impacted baby teeth, missing teeth,growth of condyles , leeway space, primate space. Ideal occlusion: ​ Occlusal plane is flat with slight curve of spee ( deepens with age) ​ Good tight proximal contacts ​ No rotated teeth are evident. ​ Upper and lower arches are symmetric and well formed ​ Crowns of teeth are tipped slightly mesially ( except max 3rd molar, it is straight up and down with slight distal inclination) ​ Incisors flare labially and rest of the teeth flare lingually. ​ Max 1st molar is tipped mesially so that it touches the mandibular first and second molars. (stolarized molar) What marks the beginning of occlusion? Begins with eruption of the primary teeth What determines the height of primary occlusion? Primary molars establish the vertical height of the primary occlusion Intercuspation:” Refers to the mesial-distal and buccal-lingual relationships that determine how the max teeth will touch,hit, and interlock with the mand teeth. Relationship of the cusps of premolars and molars in the jaw to the opposing arch during any occlusal relationship Which molar relationship is more common in children, the flush terminal plane or distal step? The flush terminal plane is more common among children than distal step. But meisal step is the most common. Mesial step (Primary occlusion has three anterior molar relationships) ​ Early forward growth of the mandible ​ Distal surface of the mand primary second molar more mesial ​ Perm molars erupt directly into class 1 ​ Can lead to class 3 Flush terminal plane ​ Distal of primary second molars are even with each other ​ Can lead to class 1 ​ End to end Distal step ​ Second mandibular is distal to the maxillary second molar ​ Can lead to class 2 or end to end Primary spaces ​ Diastemas- spaces created when the arches grow but teeth stay same size ​ Normal ​ Primate spaces- large spaces sometimes found mesial to the max primary canines and distal to man canines Leeway space ​ Space that is gained by the difference in the size of the primary molars and premolars Deep bite: ​ Condyle head is displaced distally in the glenoid fossa ​ Posterior teeth do not erupt enough ​ Muscle of mastication are so hyperactive that they prevent the eruption of posterior teeth ​ The condyle grows at an angle causing the jaw to develop in a less mesial direction ​ Over Closing of the jaw to the extent that the occluding teeth do not erupt far enough ​ Less of the mandibular incisors can be seen Clinical considerations ​ Infants that thumb suck and tongue thrust will leave permanent incisors protruded.  ​ Can push incisors too anteriorly causing protrusion. ​ Some cases pushing the alveolar ridge forward along with the rest of the bone. Will make it impossible to change after the child is 5-6 years old. Development of occlusion begins with eruption of primary teeth ​ First are central incisors mandibular, then laterals ​ At 16 months first molars erupt. Molars establish the vertical height of the primary occlusion. Also establish intercuspation (relationship between cusps while biting/chewing, when the cusps of upper teeth fit into the grooves of the lower teeth. mesial-distal , buccal- lingual relationship) also will help establish how other teeth form. ​ Primary dentition is done by 2.5 years of age ​ Average overbite is 2.5mm in children Horizontal alignment ​ Tongue acts as a huge internal force that pushes the teeth toward the lips and cheeks. ​ Forces from the cheek and lip control how far the teeth move facially. ​ If mandibular lip is overdeveloped, can cause retrusion of the mandibular teeth. ​ Intercuspation also helps prevent tooth buccally and labially Vertical alignment ​ A flat plane of occlusion is considered more stable. ​ Mandibular posterior teeth tend to tip the crowns lingually and roots laterally ​ Maxillary teeth keep the crown straighter but with slight buccal inclanation and lingual inclination of the root. ​ When viewed laterally, all teeth show a slight mesial inclination Centric relation ​ position of the mandible relative to the maxillae and is determined by the max contraction of the muscle in the jaw. ​ Bone to bone relationship guided by the TMJ Occlusion ​ Relationship of the upper jaw to the lower jaw ​ A relationship of the max teeth to the mandibular teeth. Centric occlusion ​ When jaws are closed, habitual way teeth come together normally. ​ Acquired centric occlusion ​ Habitual occlusion ​ Convenience occlusion ​ Intercuspal position ​ Tooth guided relationship Cross bite ​ When one or more teeth in the mandibular arch are located facially to their max conterparts ​ Can exist between any number of teeth  ​ Loss of space in the primary arch, being blocked out of its normal position and moved more lingual ​ If disease causes the mandible but not maxilla to grow. Acromegaly Occlusal classification ​ Skeletal classification ○​ Class 1 orthognathic : maxilla and mandible are normal ○​ Class 2 retrognathic : mandible is retruded. Distal relationship with max ​ Division 1: severe overjet,deep bite ​ Division 2: deep overbite no overjet ○​ Class 3 prognathic: mandible is protruded. Mesial relationship with maxilla. Edge to edge. ​ Dental classification- relationship of teeth ○​ Canines and first molars used to class ○​ E.H. angles classification system is most popular ○​ Class 1 occlusal relationship or a neutroclusion ○​ Class 2 distoclusion ○​ Class 3 mesioclusion ○​ Class 2 div.2 occurs when ​ Deep overbite ​ Crowded max anteriors ​ Normal overjet ​ Excessive masseter muscle development ​ In lateral excursion, last two teeth should be touching is canine right ​ Canine rise- when only the canine are in contact as the jaw moves into its working side ​ Group function- when premolars also occlude during lateral excursion. Premature contact ​ If one tooth comes into contact before the rest. It interferes and bears more force than others. ​ Can cause the tmj joint to be stretched and/or abnormal position. ​ If anteriors do not hit in centric occlusion, it is called anterior coupling. Stolarized molar- Maxillary first molar is tipped mesially so that it touches the first and second mand molars. Prehistoric people had alot of class 2 div.2 resulting in attrition Open bite: When anterior teeth do not touch but are widely separated when in centric occlusion. Open contact between the arches. Overbite: Extension of the incisal edges of the maxillary anterior teeth below the incisal edges of the mandibular anterior teeth. Average in kids is 2.5mm Overjet: Amount of facial horizontal overlap of the max teeth over the man teeth. Average in kids 3mm Centric occlusion: Position when jaws are closed teeth are in max intercuspation Interdigitation- how max and mand teeth fit together when jaw is closed, aka contact points Chapter 8 supporting structures Divided into gingival unit ​ Free gingiva ​ Attached gingiva ​ Alveolar mucosa attachment unit ​ Cementum ​ Alveolar process ​ Periodontal ligament ​ Begins at the base of the gingival sulcus attachment apparatus Gingival unit: ​ masticatory mucosa ○​ Dense mucosa ○​ Thick epithelial covering and keratinized cells. ○​ Withstands trauma, subjected while grinding food ​ Underlying mucosa ○​ Composed of dense collagen fibers. ○​ Found on the hard palate Free (marginal) gingiva Attached gingiva Alveolar mucosa Masticatory mucosa Masticatory mucosa Lining mucosa Slight mobility Tightly bound Moveable and elastic epithelium Thick epithelium layer Thinner epithelial layer Slight keratinization Keratinized Nonkerantinized No rete peg formation Rete peg formation No rete peg formation smooth Stippled surface smooth Light pink Light red to dark pink Pink to red Collagenous fibers Collagenous fibers Collagenous fibers and some muscle fibers Alveolar mucosa ( lining mucosa) ​ Found apical of the mucogingival junction ​ Continuous with the rest of the mucous membrane. ​ Thin freely moveable, tears easily ​ Loose connective tissue and muscle fibers ​ Not considered part of the periodontium, does not surround or support teeth ​ Help aid the well being of other gingival tissues that do support teeth Free gingiva (marginal gingiva) ​ Extends from gingival margin to base of gingival sulcus. ​ Attached gingiva extends from the base of the sulcus to the mucogingival junction ​ 0.5-2mm in depth ​ Gingival sulcus is the space between the free gingiva and the tooth ​ Healthy gingival sulcus is 3mm or less in depth and doesnt bleed when probed or brushed. ​ Gingival papilla ( interdental papilla) is free gingiva in between teeth. ​ Blunter in posterior teeth. ​ Shape is affected by location of contact area ​ Connective tissue fibers within the marginal and attached gingiva are called lamina propria ​ Lamina propria, periodontal ligament, attached gingiva circular fibers surround teeth keeping free gingiva firm. Attached gingiva ​ Not mobile because lamina propria is attached to the bone underneath ​ Covered by stratified squamous epithelium in which rete peg formation(causes dimples) is evident ​ Connected by collagenous fibers, formed by fibroblasts ​ Embedded fibers in the cementum or alveolar bone are known as sharpey’s fibers ​ Prevent apical migration and epithelial attachment and resist gingival recession ​ Blood supply is from supraperiosteal vessels. Alveolar mucosa ​ Apical to the attached gingiva ​ Continuous with the rest of the tissue of the vestibule. ​ Composed of lining mucosa and submucosa contains connective tissue,fat and some muscle fibers. ​ Covers buccal and lingual on maxillary but only on buccal in mand Attachment unit: periodontium ​ Made of hard and soft tissue ​ Nutrition , formative and sensory. Fulfilled by blood vessels ​ Cementoblasts,fibroblasts and osteoblasts Cementum ​ Cellular ○​ Cementoblasts embedded in the cementum  ○​ Covers the apical portion ○​ Sometimes overlap the acellular cementum ○​ Like bone, grows by apposition(addition) of new layers on top of each other ○​ Changes in function and pressure change growth ​ Acellular ○​ Clear without structure and cementoblasts ○​ Covers cervical third of the root and sometimes extends over almost all of the root Alveolar bone ​ The alveolar bone that forms the inner bone is called bundle bone. ○​ When numerous layers of bone are added to the socket wall ○​ Forms the attachment of PDL with sharpey’s fibers ○​ Between teeth is called interdental septum ○​ Attachment lining of the bone area of the tooth is called lamina dura. ​ Consists of organic matrix and inorganic matter ○​ Organic matrix comprises collagen and intercellular substance ○​ Inorganic comprises apatite crystals (calcium, phosphorus, carb) ​ Cortical bone ○​ Dense surrounding outside, buccal and lingual of alveolar process ​ Trabecular bone ○​ Forms inside the alveolar process ○​ Made of soft cancellous bone (spongy bone) ○​ Fills inside alveolar process with bone between, around teeth and between roots ○​ Crisscross of bone with holes ○​ Looks like a sponge ○​ Between the teeth is called interdental bone ○​ Bone between the multirooted teeth is interradicular bone that forms the interradicular septum Periodontal ligament ​ Attaches bone and tooth and suspends it like a hammock ​ Collagenous connective tissue fibers that run from bone to tooth. ​ Transseptal group- the transseptal group refers to a group of periodontal ligament fibers that run between the proximal surfaces (sides) of adjacent teeth, crossing the interdental septum (the bone between the teeth). These fibers help stabilize the position of the teeth relative to one another, preventing them from drifting apart or shifting position​ ​ Alveolar crest group ​ Horizontal ​ Oblique ​ Apical ​ Interradicular group ​ Fluids within the PDL act as a hydraulic pressure system on the walls of alveolous Class 3 8 class 1 9a