TY - THES ID - 134864483 TI - Occlusal stability after orthodontic treatment in patients with hypodontia AU - Jafari, Azadeh AU - Cadenas de Llano Perula, Maria AU - KU Leuven. Faculteit Geneeskunde. Opleiding Master in de tandheelkunde (Leuven) PY - 2023 PB - Leuven KU Leuven. Faculteit Geneeskunde DB - UniCat UR - https://www.unicat.be/uniCat?func=search&query=sysid:134864483 AB - Introduction and aim: The terms hypodontia or agenesis, refer to congenitally missing teeth. Hypodontia of one or two teeth is relatively prevalent, while the most severe forms are rather rare and often combined with a syndrome. The second lower premolar and the upper lateral incisors are the most common agenetic teeth. Agenesis can be caused by genetic, epigenetic and environmental factors that disrupt the initial stages of tooth development. Since mutations in a particular gene have multiple phenotypes, hypodontia often correlates with other dental abnormalities. The ideal treatment is still a matter of debate, and information on the long term stability is rather scarce, which is an important matter since agenesis can prolong treatment time and compromise its outcome. The aim of this retrospective study is to investigate the occlusal stability of orthodontically treated patients with at least 1 agenetic tooth. Material and methods: Patients with at least one agenetic tooth (excluding third molars), treated orthodontically at Department of Orthodontics of the Service of Dentistry of UZ Leuven and with orthodontic models available before (BB) and after treatment (BR) and at a follow up time point (AB) were retrospectively selected from the archive of said Department. Patients with syndromes affecting the craniofacial region were excluded. The following occlusal traits were measured on the digital models by two observers: intercanine and intermolar distance, irregularity index, overjet, overbite, mandibular midline shift and sagittal molar occlusion, by using the software Ortho Analyzer. The occlusal traits were statistically compared along the timepoints by using one- and two-way ANOVA, Tukey’s, Dunn’s and Šídák's multiple comparisons and Kruskal-Wallis test. ICC was calculated for both observers. Results: A final sample of 18 patients could be included (11 female, 7 male, mean age 11.75 years at BB, 14.50 years at BR and 15.91 years at AB, which was on average 3 years). 13 patients presented 1 or 2 agenetic teeth (G1, mean age 12.22 years at BB, 15 years at BR and 16.44 years at AB) and 5 patients presented 3 or more agenetic teeth (G2, mean age 10,33 years at BB, 13 years at BR, 15 years at AB). A significant decrease in irregularity index was found between BB and BR, which remained stable at follow up. Significant decrease of overbite was found at BR, which slightly increased again at follow – up, remaining within a normal range. Comparing groups, there was a significant difference at AB for the irregularity index (p=0,035), which increased less in G2 and overbite (p=0,035), which increased more in G2. Conclusion: This study shows that patients with hypodontia maintain occlusal stability on average 3 years after orthodontic treatment. However, crowding in the lower jaw and overbite tend to increase slightly at follow up. Patients with 3 or more agenetic teeth have less tendency for instability regarding irregularity index and present more tendency to deep bite at follow up compared to patients with 1 or 2 agenetic teeth. The results of this study need to be taken with caution due to the limited sample size and its retrospective nature. ER -