Quiz 2 Flashcards
Combining Terms of orientation
A. MESIAL, DISTAL
B. BUCCAL, LINGUAL, FACIAL, LABIAL
C. INCISAL, OCCLUSAL, GINGIVAL
Eruption (emerging)
will be used here to denote the emergence of the tooth through the gingival;
Also means the continued movement until the tooth makes contact with the opposite ones
Primary teeth
Occur at different rates; may have some with root resorption while others are being formed; all of these rates may differ from child to child; usually completely formed by about 3 yrs; permanent dentition is usually completed by about age 25 if 3rd molars are counted; calcification begins in utero 13-16 weeks, and 18-20weeks all have begun to calcify; calcification of permanents is postnatal with formation 8-12 years to complete; primary crown formation continues after birth for the centrals for 3 months, 4 months for the laterals, 7 months for the first molars, 8 1/2 months for canine, 10 1/2 months for 2nd molar
Clinical consideration
malformations; chronologies sometimes play role in form, color, arrangements; anomolies most often seen in maxillary laterals, third molars, and mandibular 2nd premolars, enamel hypoplasia (defect in thickness) develops during enamel formation, clefts, knowing characteristics of some malformations may help to find cause
Crown and Root Development (2 components)
formation of crown and roots, eruption of teeth
Root formation begins after the crown has formed
cementum forms as a covering on the root, is similar to bone, and is a thin layer, cementum of permanent teeth is much thicker than primary teeth, continued root formation aids in the tooth erupting and contacting opposites;
Root resorption
In the absence of a permanent successor, the root may only partially resorb; failure to resorb may result in prolonged retention of primary tooth
Dentition
classes (primary, mixed, permanent); prenatal begins as early as the 6th week, mandibular jaw is larger than maxilla, very little vertical dimension, primary development, no teeth visible at brith (rare exceptions), alveolar bone height increases to accommodate the increasing length of teeth
Sequence of eruption
Central incisors, lateral incisors, first molars, canine, second molar (some variation may occur) tooth size, morphology, and formation are highly inheritable characteristics
Emergence of Primary teeth
Mandibular central 8 mo (6-10)
At about 13-16 mo all 8 of primary central incisors have erupted; 1st primary molars (16 mo), usually the maxillary emerge first; primary maxillary canines 19 mo (16-22), primary mandibular canines 20 mo (17-23); primary 2nd mandibular molars 27 mo (23-31); primary 2nd maxillary molars 29 mo (25-33) Primary dentition is completed by 30 months
Mixed dentition
Begins with the emergence of mandibular 1st permanent molar and ends with the loss of the last primary tooth about 11-12 yrs. Permanent teeth do not begin eruptive movement until crown is completed; mandibular 1st molar is guided by the distal surface of the primary 2nd molar (molars are not succedaneous)
Loss of primary teeth
Premature loss due to caries affect the development of permanent dentition; lack of dental knowledge, poor attitudes of parents leads to same attitudes and habits with adult dentition, leads to a lack of space for permanent teeth, “going to lose them anyway” mentality, don’t realize may be in use from 6mo-12 yrs; contribute to the health during the important developing years; may lead to abnormal occlusion, loss of arch length, and crowding
Permanent dentition
All 32 teeth completed 18-25 years of age; 4 centers of formation (developmental lobes); injuries during dentinogenesis leads to anomalies ; sites of fusion can show developmental grooves; follicles of developing incisors and canines are lingual to deciduous roots (it will eventually move forward); follicles of premolars are in bifurcation of deciduous roots; incisors, canines, and premolars are succedaneous- they take the place of their primary predecessors
Emerging sequence of permanent teeth
1st molars, central incisors (6-7) mandibular before maxillary, may erupt at same time as the mandibular 1st molar; mandibular lateral may erupt along with central incisor, before central incisors can take their place, the primary must be exfoliated, maxillary centrals, maxillary laterals about a year after centrals, first premolars at about 10 years, mandibular canines at about same time as first premolars, and second premolars during next year, maxillary canines, 2nd molars at about 12 yr, third molars about 17 or later
size of teeth
genetically determined for the most part, also has to do with racial differences (Lapp-small, aborigines-large)
dental pulp
CT with arteries, veins, lymphatic system, nerves; is large in primary teeth and young permanent, hence these teeth are more sensitive than teeth in older people, pulp gets smaller with age due to deposition of secondary dentin
Cementoenamel Junction Types
- Enamel overlaps cementum (excess enamel)- happens in posterior teeth in bifurcation (fibers can’t attach) 2. end to end 3. gap exposing dentin (sensitive to decay) 4. cementum overlapping enamel 5. enamel extending into bifurcation of molars creates periodontal risks 6. periodontal fibers can’t embed into enamel; epithelium attachment
Dental age
General rules is that when the last tooth has been completed, skeleton is near maturation; while teeth are forming, very little environmental influences will affect teeth; tetracycline is one exception- brown to bluish color; fluoride will make enamel less susceptible to caries; excess fluoride will result in fluorosis- white to brownish spots or bands; children should only be given a pea sized amount of fluoride paste under age 3
Permanent Mandibular Incisors Intro
Smallest mesiodistal dimensions; central somewhat smaller than lateral- opposite with maxillary; mamelons worn away early, contact areas are near the incisal ridges (incisal third area) near the same level for all; very few anomalies; labial surfaces are inclined lingually so that ridges are lingual to bisecting line of root
Permanent Mandibular central
is smallest tooth, crown has slightly more than half the mesiodistal diameter of maxillary central incisor; labiolingual dimension is 1mm less than maxillary central; masticatory stress is in a labio-lingual direction (reinforcement); root is narrow mesiodistal, wide labiolingual, length of root is as great if not longer than maxillary central incisors