JVD 2020 #3 Morphology of the Cementoenamel Junction in Permanent Teeth of Dogs: A Scanning Electron Microscopic Study; Hernandez Flashcards
What are Choquet cases of cementoenamel junction morphologies
Types of human CEJ morphology (4 types)
What is type 1 CEJ morphology
The cementum overlaps the enamel
What is type 2 CEJ morphology
The enamel overlaps the cementum
What is type 3 CEJ morphology
Cementum and enamel are edge-to-edge
What is type 4 CEJ morphology
Gap between the enamel and cementum with exposed dentin
What was the most prevalent type of CEJ morphology in dogs?
Type 3, either alone or in combination, 90.7% of samples
What was the 2nd most prevalent type of CEJ morphology in dogs?
Type 4, gap with exposed dentin. Present in 31.58% of samples
How many teeth samples showed only one type
65.13%
How many teeth samples showed a combination of types?
34.87%
The CEJ of dogs evaluated showed a high degree of variability in:
different types of teeth
within a same tooth
within the dentition of a single individual
and among individuals
Which type of CEJ morphology?
Type 1- Cementum overlapping the enamel
Which type of CEJ morphology?
Type 2- Enamel overlapping cementum
Which type of CEJ morphology?
Type 3- Edge-to-edge relationship between the cementum and enamel
The most common type in dogs (alone or in combo) 90.79% of samples
Which type of CEJ morphology?
Type 4- Gap between the enamel and cementum with exposed dentin.
Second most common type in dogs- 31.58% (alone or in combo)
What causes an irregular limit of cervical enamel in its marginal edge and an irregular onset of the formation and deposition of cementum?
Non-uniform fragmentation of Hertwig’s epithelial root sheath.
What is Hertwig’s epithelial root sheath?
The enamel organ gives rise to Hertwig’s epithelial root sheath which is 2 epithelial layers: inner and outer epithelium. After enamel formation, the sheath irregularly fragments in time and space promoting deposition of cementum onto the newly formed dentin. After fragmentation, it participates in cementogeneis and formation of the periodontal ligament, giving rise to epithelial rests of Malassez.
CEJ type 2 (enamel covering cementum) should not be embryologically possible, why?
Because development of the enamel ceases before that of the cementum. Those seen in the study were only in small segments or some kind of enamel strips on the cementum. These regions may be explained by existence of a hyperactive Hertwig’s sheath as it happens in formation of enamel pearls.
In DeLaurier et.al. Analysis of the characteristics and mineralization status of feline teeth using scanning elecron microscopy. J Anat. 2006 , what type of CEJ was most common in cats and how does this relate to pathology?
Type 4 CEJ (gap between E &C) was most common followed by type 3 (edge-to-edge).
Suggested a possible relationship between the presence of exposed dentin and development of resorptive lesions.
