Tooth Eruption - USC
Dr Sameshima CBY 579 lecture notes ChronologyBiologyAnkylosisInfraocclusion or submerged teethPrimary Failure of EruptionTooth MigrationClassic ADA North American Standards for Tooth DevelopmentEruption sequence Maxillary teeth: 6 1 2 4 5 3 7 Mandibular teeth: 6 1 2 3 4 5 7 Females develop slightly earlier than malesStandards on based on data several decades old in theUS using Caucasian populations of Northern Europeanancestry1
Dr Sameshima CBY 579 lecture notesHAVE THERE BEEN ANY CHANGESREPORTED IN THE LAST FEW DECADES?Emergence of permanent teeth and dental age in a series ofFinns – Nystrom et al. Acta Odontologica Scandinavia April2001. 68% of children – lower 1s erupted before 6s – shiftin emergence order in last 30 yearsNew standards for emergence of permanent teeth inAustralians – Diamanti and Townsend. Australian Dental J.2008. Eruption rate of all permanent teeth delayedcompared to data from previous years.Expected location of neonatal lineThe Consideration of Dental Development In Serial extraction- Moorrees CA, Fanning EA, Gron AM. AJO 1963. OLD BUT STILLUSEFUL2
Dr Sameshima CBY 579 lecture notesThe Consideration of Dental Development In Serial extraction Moorrees CA, Fanning EA, Gron AM. AJO 1963.The Consideration of Dental Development In Serial extraction Moorrees CA, Fanning EA, Gron AM. AJO 1963.The Consideration of Dental Development In Serial extraction Moorrees CA, Fanning EA, Gron AM. AJO 1963.3
Dr Sameshima CBY 579 lecture notesThe Consideration of Dental Development In Serial extraction Moorrees CA, Fanning EA, Gron AM. AJO 1963.BIOLOGY OF TOOTH ERUPTION Definition:movement of a tooth from its site ofdevelopment within the alveolar process. Research has shownthat eruption of teeth continues well into the fourth and fifthdecades of life albeit on a smaller scale.Theories of tooth eruption Discounted1. Pulpal pressure2. Pulpal growth3. PDL fibroblasttraction4. Vascularpressure Newer1. Rootelongation2. Alveolar boneremodeling3. Periodontalligamentformation4. Dental follicle4
Dr Sameshima CBY 579 lecture notes1. Root elongation theory Basis : Not biological Does not explain movement in threedimensional space Teeth without roots erupt (Dentin dysplasiaType I) May account for eruption acceleration5
Dr Sameshima CBY 579 lecture notes2. Periodontal ligament theory Basis : Fibers in PDL Presence of PDL does not assure eruption Osteopetrotic mutations - PDL present but noeruption Dentinal dysplasia - no PDL but teeth erupt Previous research was done on rodents with teeththat erupt continuously3. Alveolar bone remodeling theory Basis : Alveolar bone growth, toothdevelopment and tooth eruption are closelyrelated Bone formation per se is not sufficient fortooth eruption (cleidocranial dysplasia)6
Dr Sameshima CBY 579 lecture notes4. Dental Follicle Theory Basis : Clastic cells in DF Eruption begins only after crown formation is complete– Clastic cells surrounding crown not activated until enamel formation iscomplete (Proffit) Root formation occurs initially at the expense of basal bonewithout movement of the crown Most root growth occurs during the stage of preocclusaleruption Root completion is at the expense of basal bone Tooth eruption and bone formation depend on the dentalfollicle - Marks, CahillCahill and Marks Famous ExperimentBeagle Dog Teeth7
Dr Sameshima CBY 579 lecture notesNature’s Evidence that the dental follicle creates theeruption pathwayFrom Proffit’s articleFive stages of tooth eruption:1.2.3.4.5.Preeruptive movementsIntraosseous eruptionMucosal penetrationPreocclusal eruptionPostocclusal eruptionFive stages of tooth eruption:8
Dr Sameshima CBY 579 lecture notesStage 1: Preeruptive movements Random, very short movements Cause unknown - development of dental follicle orregional growth of the jaws Gubernacular canals - small remnants of the originalinvagination of oral ectodermStage 2: Intraosseous stage Rate limiting step in early eruption is formation of an eruptionpathway by osteoclasts - shown by Cahill in dogs No osteoclasts - no eruption - by Sundquist 1994 Bony deposition occurs at apical end of dental follicle If crown is removed but not DF eruption still takes place Marks 1985Stage 2 continued NO DF - no eruptionRemoval of coronal half - no eruptionRemoval of apical half - no eruptionRemoval of crown & replacement with a metal tooth- eruption Early experiments removed enamel epithelium Enamel organ alone insufficient for eruption - Larson19959
Dr Sameshima CBY 579 lecture notesStage 2 continued Fragmentation of a sialoprotein (DF-95) seems tomark the onset of preosseous eruption - Gorski 1994 Proposed pathway: activation of proteases from theenamel organ at the completion of crown formationinitiates eruption by release of metalloproteinasesfrom the dental follicle - Marks 1996 Root formation is a consequence not a cause oftooth eruption Enamel organ is involved CSF-a, EGF, TGF-B, and IL-1 are likely candidatesfor local molecular regulation Bone resorption is the rate-limiting step of thisstage Orientation of follicle – differential geneexpression linked to nuclear matrix – intermediatefilament proteins – see Bidwell et al, Arch OralBiology 1995. Primate experiments - transplantation failures due todamage follicle Root growth is usually fast enough to keep up witheruption Marks’ summary: Primary determinant of both thedirection and rate of tooth eruption is the rate offormation of the eruption pathway and itscoordination with bone formation in selected areasof the crypt and alveolar bone10
Dr Sameshima CBY 579 lecture notesStage 3: Mucosal penetration Enamel epithelium fuses with oral epithelium Rate of eruption increases when cusps reach alveolarcrest Clinical signs of hypersensitivity (“teething”) duringthis stage are thought to be from release of enamelmatrix proteinsStage 4: Preocclusal eruption Major event: Formation of junctional epithelium- notmuch known about this - Marks Rate of preocclusal eruption : 75 microns per day Proffit 1991 using a high resolution video microscopecustom madeStage 5: Eruption at the Occlusal Plane Tooth eruption slowsAlveolar bone becomes denser around teeth (lamina dura)Maturation/organization of fibers of periodontal ligamentProffitt: Shrinkage of collagen fibers; also claims majorfactor is blood pressure from pulp (Old study showedvasodilator increasesed eruption rate) Determinants of final positioning not known - possiblyEnlow’s drift11
Dr Sameshima CBY 579 lecture notesEctopic EruptionDefinition: Eruption occurring in an abnormal position orplace-1.2% of children in North AmericaUnknown causes but probably geneticCan cause:-A) Resorption of a primary tooth other than the one it is supposed to replace orB) Resorption of an adjacent primary or permanent toothOver-retained teeth Defined as a primary tooth still present when 3/4 ofroot of permanent successor has formed Possibly some root of primary tooth present Should extract if not much mobility Also extract if major part of root present (e.g. distalof primary first or second molar)Note: If appliances are placed on primary teeth and forcesapplied, the primary tooth root will usually resorb – urbanmyth?12
Dr Sameshima CBY 579 lecture notesDelayed eruption Children whose primary or permanent teeth eruptsix months or later than normal, or who haveasymmetric eruption, should be evaluated forabnormal dental eruption or congenitally missingteeth. Delays in dental eruption can be familial or can occurwith conditions such as:––––Down syndromeHypothyroidism, hypopituitarismAchondroplastic dwarfismOsteopetrosis, rickets, or chondroectodermal dysplasia.ANKYLOSIS of primary teeth Causes:– Genetics (inherited)– Trauma Diagnosis:– Submergence Shorter tooth than permanent neighbors so watch bone level– could be normal if pdl levels are the same Serial BWXRs or PANs useful if not sure Sound not diagnostic (see permanent teeth) DOJun2002.pdfANKYLOSIS of primary teeth If succedaneous tooth present:– Use as a space maintainer as long as possible– Extract when over one half of successor root formed Why? Causes delay in eruption If no successor:– Extract ASAP– Move teeth into space for bone– Careful extraction - potential serious periodontalproblems - also if wait too long to OJun2002.pdf13
Dr Sameshima CBY 579 lecture notesANKYLOSIS of permanent teeth Causes : Genetics or trauma - damage to PDL Diagnosis - history, percussion Treatment - none or extraction - subluxationrarely helps Ectopic canines (& other impacted teeth) occasionally ankylosed - probably iatrogenic inmost cases (Becker)PERIO, ENDO, AND RESTORATIVE RESIDENTSPLEASE KNOW HOW TO DO THIS !!!11 y.o. boy traumatic injury. Left central incisor reimplanted 12hours later. One year after trauma – note replacementresorption14
Dr Sameshima CBY 579 lecture notes“Decoronation “ procedure : crown is removed and tissuesutured over to cover the resorbing rootThe goal is to preserveperiosteum across theextraction site. Alveolar bonegrowth will occur under ahealthy periosteum.Beware of : Infraocclusion or submergedteeth Primary dentitionEtiology unknownTeeth are not ankylosedKurol - 9% of primary molars so affectedNo treatment required unless teeth are tipped intospace or there is no permanent successor15
Dr Sameshima CBY 579 lecture notesPrimary failure of tooth eruption Primary and secondary dentitions fail to erupt Surgical exposure and orthodontic treatmentdo not work No other systemic problems Skeletal/facial growth normalPRIMARY FAILURE OF ERUPTION16
Dr Sameshima CBY 579 lecture notesPFE Summary Rare, familial Must distinguish between mechanicalobstruction, isolated ankylosis, and PFE Occurs at post-emergent stage Almost always posterior permanent teeth Cannot treat with conventional orthodonticmechanotherapyABO READING LISTTooth agenesis: some common terms: oligodontia, anodontia,partial anodontia, hypodontia17
Dr Sameshima CBY 579 lecture notesUnopposed tooth eruption Craddock HL, Youngson CC. A study of the incidence ofovereruption and occlusal interferences in unopposedposterior teeth. Br Dent J. 2004 Mar 27;196(6):341-8.– 86% of 155 unopposed teeth overerupted– 52% caused occusal interferences in function18
Basis : Fibers in PDL Presence of PDL does not assure eruption Osteopetrotic mutations - PDL present but no eruption Dentinal dysplasia - no PDL but teeth erupt Previous research was done on rodents with teeth that erupt continuously 3. Alveolar bone remodeling theory Basis : Alveolar
USC Thornton School of Music Elizabeth M. Daley USC School of Cinematic Arts Gerald C. Davison USC Davis School of Gerontology James G. Ellis USC Marshall School of Business Marilyn L. Flynn USC School of Social Work Karen Symms Gallagher USC Rossier School of Education Howard Gillman USC Dor
jcbrown@usc.edu 213-740-7121. emeriti.usc.edu Office of the Vice Provost for Faculty Affairs Debbie Jones. Faculty Retirement Navigator. jonesdeb@usc.edu 213-740-7641. faculty.usc.edu USC Office of Benefits Administration Keri Marroquin. Benefits Retirement Navigator. kerimarr@usc.edu 213-821-8100.
Third molar (wisdom tooth) 17-21 yrs. Lower Teeth Erupt Third molar (wisdom tooth) 17-21 yrs. Second molar 12-13 yrs. First molar 6-7 yrs. Second premolar (second bicuspid) 10-12 yrs. First premolar (first bicuspid) 10-11 yrs. Canine (cuspid) 11-12 yrs. Lateral incisor 8-9 yrs. Central incisor 7-8 yrs. 210610_Dentition Guide 7/17/01 6:39 PM Page 3
account @ https://you.usc.edu/login/ This service gives you access to your: a) University Decision Letter b) Welcome to USC brochure c) If admitted, Certification of Enrollment Contact Information Office of Graduate Admission gradadm@usc.edu MSF Program ms.fin@marshall.usc.edu Immigration (I-20 and visa questions) usci20@usc.edu .
Revise 524.3 Anomalies of tooth position of fully erupted teeth Add Excludes: impacted or embedded teeth with abnormal position of such teeth or adjacent teeth (520.6) Delete Crowding of tooth, teeth Diastema of tooth, teeth Displacement of tooth, teeth Rotation of tooth, teeth Spacing, abnormal, of tooth
The Wisdom Tooth, first climbed in 1980 by Ken Nichols and Al Rubin, showing the line of Infinite Jest and its two starting options (IV 5.11 A2, right, or IV 5.10 A2, left). The craggy east face of Dog Tooth Peak, showing the steep Dog Tooth Spire (left) and the Wisdom Tooth. The right start of Infinite Jest climbs the obvious shaded dihedral.
F, Clinical crown ap-pearance into the oral cavity (pre-functional stage). G, Tooth erupting into functional occlusion. First-formed fibers Tooth below alveolar crest Tooth above alveolar crest a a b c c b a A B C Fig. 6.20 Principal fiber development during tooth eruption. A, Origin of fibers at the cervical root area of crown. B, Fiber .
1 1 Novel engineered high performance sugar beetroot 2D nanoplatelet-cementitious 2 composites 3. 4. Hasan Hasan. 1, Bo Huang , Mohamed Saafi. 1 *, Jiawei Sun. 2, Yin .
