What are perikymata and imbrication lines?
Brownish lines, the striae of Retzius, develop as a result of a change in the growth process. Macroscopically, these lines can be seen on the labial surface or lip side of anterior or front teeth as horizontal lines on the tooth crown, also known as perikymata or “imbrication lines” .
What causes perikymata?
The appositional secretion process of the enamel during its histogenesis creates a series of striations on the surface of the dental crown in the form of grooves known as Perikymata (Simmer & Hu, 2001).
What is the process of amelogenesis?
The process of amelogenesis is divided into five stages: the presecretory stage, the secretory stage, the transition stage, the maturation stage, and the reduced ameloblast stage. The presecretory stage is referred to the enamel organ, before the enamel matrix is created.
At which of the following locations are perikymata usually found?
Perikymata are the expression of striae of Retzius at the surface of enamel. They can be found on all teeth, but are usually the easiest to notice on anterior teeth (incisors and canines).
What causes striae of Retzius?
Striae of Retzius occur due to the slowing down of ameloblastic activity at regular intervals (Bromage et al., 2009). Striae periodicity refers to the number of daily increments, represented by cross-striations, between two adjacent striae of Retzius.
What is a perikymata in dentistry?
Perikymata are wavelike features that are normally found in the surface enamel of teeth. These structures are known to undergo regressive changes due to gradual attrition, mechanical abrasion, or chemical erosion.
What is the meaning of amelogenesis?
the formation of enamel
Amelogenesis is the formation of enamel by ameloblasts of epithelial origin facing the odontoblast layer (Figure 26.3). Differentiation of ameloblasts is initiated by more advanced odontoblasts and the cells of stratum intermedium via molecular signals, such as BMP and FGF.
What do ameloblasts produce?
1 Origins of Tooth Cells Ameloblasts secrete enamel matrix and are derived from oral ectodermal cells. Odontoblasts produce dentine and develop from CNC cells, as do all other supporting dental cells. Ameloblasts are the only cells remaining in teeth at birth that are derived from the ectoderm.
What is a Perikymata in dentistry?