Tooth Eruption and Movement

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Tooth eruption and movement

Dr. Krisztián Nagy

CÍM beírása!!! DÁTUM Diphydont dentition

Deciduous dentition – primary dentition

CÍM beírása!!! DÁTUM Diphydont dentition

Permanent dentition – secondary dentition

CÍM beírása!!! DÁTUM Mixed Dentition: Presence of both dentitions

CÍM beírása!!! DÁTUM Tooth eruption

CÍM beírása!!! DÁTUM • Teeth are formed in relation to the alveolar process. • Epithelial thickening: Dental lamina • Enamel organs: Series of 10 local thickenings on dental lamina in each alveolar process. • Each thickening forms one milk tooth.

CÍM beírása!!! DÁTUM Stages in the formation of a tooth germ

CÍM beírása!!! DÁTUM Formation of enamel organs

CÍM beírása!!! DÁTUM Stages

Bud stage : • Characterized by formation of a tooth bud. • The epithelial cells begin to proliferate into the ectomesenchyme of the jaw.

CÍM beírása!!! DÁTUM Cap stage :

• Formation of dental papilla. • The enamel organ & dental papilla forms the tooth germ. • Formation of ameloblasts. • Formation of odontoblasts.

CÍM beírása!!! DÁTUM Bell stage:

The cells on the periphery of the enamel organ separate into three important layers: • Cuboidal cells on the periphery of the dental organ form the outer enamel epithelium. • The cells of the enamel organ adjacent to the dental papilla form the inner enamel epithelium. • The cells between the inner enamel epithelium and the stellate reticulum form a layer known as the stratum intermedium. The dental lamina begin to disintegrates, leaving the developing teeth completely separated from the epithelium of the oral cavity.

CÍM beírása!!! DÁTUM Crown stage :

1. Mineralization of hard tissues occur.

2. The inner enamel epithelial cells change in shape from cuboidal to columnar. The nuclei of these cells move closer to the stratum intermedium and away from the dental papilla.

3. The adjacent layer of cells in the dental papilla suddenly increases in size and differentiates into odontoblasts, which form dentin.

4. The inner enamel epithelium and the formation of odontoblasts continue from the tips of the cusps.

CÍM beírása!!! DÁTUM Preeruption phase- crown phase

CÍM beírása!!! DÁTUM Origin of germs of permanent teeth

CÍM beírása!!! DÁTUM Preeruption phase

CÍM beírása!!! DÁTUM Root formation

CÍM beírása!!! DÁTUM Eruption phase – movement

CÍM beírása!!! DÁTUM CÍM beírása!!! DÁTUM Eruption phase – movement

CÍM beírása!!! DÁTUM Eruption phase – breakthrough

CÍM beírása!!! DÁTUM Eruption phase – occlusal contact

CÍM beírása!!! DÁTUM Eruption cascade

CÍM beírása!!! DÁTUM Sequence of tooth eruption

CÍM beírása!!! DÁTUM

05/1985 04/1987

11/1989 04/1991

09/1996 02/1999

CÍM beírása!!! DÁTUM

Sequence of tooth eruption

Age Tooth Girls Boys 6 y 6 - 6 5,94 6,21 6 + 6 6,22 6,40 1 - 1 6,26 5,54 7 y 1 + 1 7,20 7,47 2 - 2 7,34 7,70 8 y 2 + 2 8,20 8,26 10 y 3 - 3 9,86 10,79 4 + 4 10,03 10,40 4 - 4 10,18 10,82 11 y 5 + 5 10,88 11,18 5 - 5 10,89 11,47 3 + 3 10,98 11,69 12 y 7 - 7 11,66 12,12 7 + 7 12,27 12,68 18 - 22 y 8 +/- 8

CÍM beírása!!! DÁTUM Eruption phase – occlusal contact

5 months At birth 1 year

CÍM beírása!!!2 years 3.5 years 4.5 years DÁTUM Posteruption phase

7 years-functional occlusion attained 15 years – incisal wear but root apex is still not fully formed

CÍM beírása!!! DÁTUM Some data

The rate of tooth eruption depends on the phase of movement

Intraosseous phase: 1 to 10 µm/day

Extraosseous phase: 75 μm/day

CÍM beírása!!! DÁTUM Presurgical naso-alvolear molding

CÍM beírása!!! DÁTUM Bilateral cleft lip, alveolus and palate

CÍM beírása!!! DÁTUM Secondary cases

18 months 2 years

CÍM beírása!!! DÁTUM Abnormalities

1. Dentitio tarda 2. External resorption 3. General resorption disorders 4. Ankylotic primary teeth 5. Aplasia, oligodontia, hypodontia 6. Remaining primary teeth 7. Eruption disorders

CÍM beírása!!! DÁTUM Dentitio tarda

6.5 year 9 year

10.5 year 12 year

CÍM beírása!!! DÁTUM External resorption

CÍM beírása!!! DÁTUM General resorption disorders

CÍM beírása!!! DÁTUM Eruption disorders – hormonal

Familial, nonsyndromic PFE is caused by heterozygous mutations in the gene encoding the G protein-coupled receptor for parathyroid hormone and parathyroid hormone-like hormone (PTHR1) - Decker et al., 2008

CÍM beírása!!! DÁTUM Submerged primary teeth

CÍM beírása!!! DÁTUM Ankylosis

CÍM beírása!!! DÁTUM Retained primary teeth

CÍM beírása!!! DÁTUM Aplasia / oligodontia

Anodontia = primary dental aplasia

Total anodontia ectodermal dysplasia Partial anodontia (oligodontia) Hypodontia (last missing) M3 10-25% P2 3-4% I2 2%

CÍM beírása!!! DÁTUM Congenitally Missing Teeth

CÍM beírása!!! DÁTUM Natal and Neonatal Teeth

CÍM beírása!!! DÁTUM Eruption disoders

Frontal region

Canine region

Premolar region

Molar region

Wisdom tooth region

CÍM beírása!!! DÁTUM Supporting zone

CÍM beírása!!! DÁTUM Lost of support

CÍM beírása!!! DÁTUM Maintain space!

Space maintainer

Lip-bumper Transpalatinal-arch

Lingual-arch

CÍM beírása!!! DÁTUM Tooth movement

CÍM beírása!!! DÁTUM Eqilibrium theory

BITE

TONGUE LIP, BUCCAL TISSUES

ERUPTION

CÍM beírása!!! DÁTUM Dental movement

Physiological: Eruption Pathological: Early primary or secondary tooth extraction Tumor Thumb sucking Muscular dysfunction Therapeutical: Orthodontics

CÍM beírása!!! DÁTUM Guidance with functional apparatus

Fränkel III

CÍM beírása!!! DÁTUM Guidance with functional apparatus

Lip bumper

CÍM beírása!!! DÁTUM Basic principles of orthodontics

• Bony appositon by traction and resorption on pressure • Too much pressure will cause capillary compression and hyalinization • Effective orthodontic force correlates with root surface • Newton III. rule: Action=Reaction. It is impossible to move only one tooth, only with skeletal anchorage

CÍM beírása!!! DÁTUM Guided extrusion of impacted tooth

CÍM beírása!!! DÁTUM Box-loop

CÍM beírása!!! DÁTUM Skeletal anchorage

Headgear

CÍM beírása!!! DÁTUM Skeletal anchorage

Palatinal mini- implant Vestibular mini-implant

CÍM beírása!!! DÁTUM Forced extrusion in periodontally lost case

Only traction – bony apposition

CÍM beírása!!! DÁTUM Thank you very much for your kind attention!

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CÍM beírása!!! DÁTUM Histology – Surrounding tissues

The surrounding fibers change from being parallel to the tooth surface to bundles that are attached to the tooth surface and extending towards the periodontium (bone)

The periodontal ligament have contractile properties and changes drastically during eruption

During eruption, collagen fiber formation and turnover are rapid enabling fibers to attach and release and attach in rapid succession. Some fibers may attach and reattach later while the tooth moves occlusally as new bone forms around it and the fibers will organize and increase in number and density as the tooth erupts

rxdentistry.net CÍM beírása!!! DÁTUM Histology – Underlying tissues

As the tooth moves occlusally it creates space underneath the tooth to accommodate root formation

Fibroblasts around the root apex form collagen that attach to the newly formed cementum

Bone trabeculae fill in the space left behind as the tooth erupts in the pattern of a ladder which gets denser as the tooth erupts

After tooth reaches functional occlusion periodontal fibers attach to the apical cementum and extend into the adjacent alveolar bone

CÍM beírása!!! DÁTUM Mechanisms of Eruptive Tooth Movement

Eruption is a multifactorial process

The accepted theories of tooth eruption are: 1. Root Formation. Should be an obvious cause of tooth eruption. But studies have not provided evidence for this. If a tooth that is continuously erupting (rodent incisor and guinea pig molar) is prevented the root still forms by causing bone resorption. Rootless tooth still erupt, some teeth erupt more than the total length of the roots and the teeth still erupt after completion of root formation. Therefore root formation is accommodated during eruption and may not be the cause of tooth eruption.

One point of importance is that, the tissue beneath the growing root resists the apical movement of the developing root. This resistance results in the occlusal movement of the tooth crown as the root lengthens.

CÍM beírása!!! DÁTUM Mechanisms of Eruptive Tooth Movement

2. Bone Remodeling. Major proof is when a mand PM is removed without disturbing its follicle or you wire down the tooth germ, an eruptive pathway still forms within bone as osteoclasts widen the gubernacular canal. If the dental follicle is also removed no eruption path develops. So not sure if bone remodeling plays a significant role but is involved.

One point to remember: Bone formation also occurs apical to the developing tooth

• Dental Follicle. Studies have shown that the reduced dental epithelium initiates a cascade of intercellular signals that recruit osteoclasts to the follicle. By providing a signal and chemoattractant for osteoclasts, it is possible that the dental follicle can initiate bone remodeling which goes with tooth eruption. Teeth eruption is delayed or absent in animal models and human diseases that cause a defect in osteoclast differentiation.

CÍM beírása!!! DÁTUM Mechanisms of Eruptive Tooth Movement

4. Periodontal ligament. Formation and renewal of PDL can be a factor in tooth eruption because of the traction power of the fibroblasts. However, presence of PDL does not always correlate with tooth eruption. Other factors involved are vascular pressures within the PDL. Examples of PDL being present but tooth not erupting and rootless teeth erupting have been reported.

CÍM beírása!!! DÁTUM Post Eruptive Tooth Movement

1. Movements to accommodate the growing jaws. Mostly occurs between 14 and 18 years by formation of new bone at the alveolar crest and base of socket to keep pace wit increasing height of jaws.

2. Movements to compensate for continued occlusal wear. Compensation primarily occurs by continuous deposition of cementum around the apex of the tooth. However, this deposition occurs only after tooth moves. Similar to eruptive tooth movement.

3. Movements to accommodate interproximal wear. Compensated by mesial or approximal drift. Mesial drift is the lateral bodily movement of teeth on both sides of the mouth. Very important in orthodontics.

CÍM beírása!!! DÁTUM