# Analysis of Natural Clinical Crown Height Changes in Central Incisors and First Molars from Age 8 to 18: A Retrospective Digital Study

## TL;DR

This study tracks how the visible part of certain teeth grows in children aged 8 to 18, finding that they keep growing past 18 years.

## Contribution

The study provides new longitudinal data on clinical crown height changes in specific teeth beyond the age of 18.

## Key findings

- Clinical crown height of central incisors and first molars increased significantly with age (p-value < 0.001).
- Upper central incisors increased by 1.5 mm, while lower ones increased by 0.8 mm on average.
- Upper first molars increased by 2.7 mm and lower first molars by 2.1 mm on average.

## Abstract

Objective: This thesis aims to digitally study the natural longitudinal evolution of clinical crown height in maxillary and mandibular central incisors and first molars between 8 and 18 years of age. Methods: A total of 31 subjects (17 females and 14 males) were selected for the study. Their plaster study models were converted to digital format using a three-dimensional scanner. Digital anatomical landmarks were placed on the central incisors and first molars of all dental arches. The clinical crown height of the central incisors and first molars was then analyzed digitally and longitudinally, based on the position of the marginal gingiva on the vestibular surface of the teeth in question. Results: The clinical crown height of maxillary and mandibular central incisors and first molars increased significantly with age (p-value < 0.001) from 8 to 18 years. On average, the clinical crown height increased by 1.5 mm for the upper central incisors and 0.8 mm for the mandibular central incisors. The clinical crown height of the upper first molar increased on average by 2.7 mm and 2.1 mm for mandibular first molars. Conclusions: The clinical crown height of maxillary and mandibular central incisors and first molars appears to continue increasing beyond 18 years of age. These results suggest that the position of the marginal gingiva on the buccal surface of the teeth is not stable at 18 years of age.