In Dentinal dysplasia type 1, which of the following is consistently seen?

In Dentinal Dysplasia Type 1, the defining characteristic is the abnormal development and morphology of the teeth, particularly affecting the roots. One of the notable features of this condition is the absence of roots, which leads to a significant effect on the overall structure of the teeth. This condition results from a developmental issue where the dental pulp does not properly form or is absent altogether, leading to the characteristic lack of roots.

The other choices do not accurately represent the typical findings in Dentinal Dysplasia Type 1. For example, normal length roots or thistle-shaped pulp chambers are not consistent with this condition, as the dysplasia typically leads to very short or absent roots and abnormal root morphology. Similarly, while pulp necrosis can occur in various dental conditions, it is not a defining characteristic of Dentinal Dysplasia Type 1 and may not be present in all cases.

Therefore, the presence of no roots is consistently associated with Dentinal Dysplasia Type 1 and is a direct consequence of the dental development issues inherent in this condition.