Does craniofacial morphology affect third molars impaction? Results from a population-based study in northeastern Germany.

OBJECTIVES: It is still not clear why impaction of third molars occurs. Craniofacial morphology and facial parameters have been discussed to be strong predictors for third molar impaction. Thus, this study aimed to investigate the effect of craniofacial morphology on erupted or impacted third molars in a German population sample. MATERIALS AND METHODS: Erupted and impacted third molars in 2,484 participants from the Study of Health in Pomerania were assessed by whole-body magnetic resonance imaging. Markers of facial morphology were determined in 619 individuals of those participants in whose 421 participants (16.7%) had at least one impacted third molar. Craniofacial morphology was estimated as linear measurements and was associated in a cross-sectional study design with impacted and erupted third molars by multinomial logistic regression models. Erupted third molars were used as reference outcome category and regression models were adjusted for age and sex. RESULTS: Maximum Cranial Width (Eurion-Eurion distance) was significantly associated with impacted third molars (RR: 1.079; 95% confidence interval 1.028-1.132). This association was even more pronounced in the mandible. Individuals with a lower total anterior facial height (Nasion-Menton distance) and a lower facial index also have an increased risk for impacted third molars in the mandible (RR 0.953; 95% confidence interval 0.913-0.996 and RR: 0.943; 95% confidence interval 0.894-0.995). No significant associations of third molar status with facial width (Zygion-Zygion distance), and sagittal cranial dimension (Nasion-Sella distance; Sella-Basion distance) were observed. CONCLUSION: Individuals with an increased maximal cranial width have a higher risk for impaction of third molars in the mandible and in the maxilla. Individuals with a lower anterior total anterior facial height and lower facial index also have an increased risk for third molars impaction in the mandible. These findings could help orthodontic dentists, oral surgeons and oral and maxillofacial surgeons in decision-making for third molars removal in their treatment. These findings highlight the necessity of an additional analysis of the maximal cranial width by the Eurion- Eurion distance.

Fully digital workflow for presurgical orthodontic plate in cleft lip and palate patients.

OBJECTIVE: In most cases, according to our treatment concept, a presurgical orthodontic treatment (POT) is performed on patients with cleft lip and palate (CLP). The aim of this case report is to demonstrate a completely digital workflow for the production of a palate plate. MATERIALS AND METHODS: For the assessment of the maxillary arch, a digital impression of the jaw was made on two patients with an intraoral scanner (Cerec Omnicam Ortho). After reconstruction of a virtual model from the scan data, appropriate areas of the jaw could be blocked out and a plate constructed. This was printed with a DLP three-dimensional (3D) printer (SHERA EcoPrint D30) with class IIa biocompatible material. After minor surface finishing, the plates could be incorporated in the patients' mouths. RESULTS: The scans could be performed in a short time without affecting the very young patients. All clinically relevant areas for the production and digital measurement of the models could be recorded. The plates showed an extremely good fit, and there were no differences in wear compared with a conventionally manufactured plate. CONCLUSION: For the first time, a risk-free digital impression of the edentulous jaw in CLP babies with a subsequently completely digitally constructed and 3D-printed palatal plate could be shown.

Three-dimensional morphology of first molars in relation to ethnicity and the occurrence of cleft lip and palate.

OBJECTIVES: This study aims to describe morphological peculiarities of maxillary and mandibular first molars in Europeans, Asians and Europeans with cleft lip and palate. MATERIAL AND METHODS: Reflex microscopy was used to obtain three-dimensional morphometric landmarks from 40 models (11 Europeans and 13 Asians without cleft lip and palate, 16 Europeans with unilateral cleft lip and palate). The cases were examined using traditional morphometry and geometric morphometry, and visualized using thin-plate splines. RESULTS: Classic morphometry showed no right/left differences in the study groups and no significant differences with regard to the cleft side in patients with cleft lip and palate. In Asians, a significantly greater mesiodistal width was found. Geometric morphometry showed an enlarged centroid size in Asians (maxilla and mandible). In cleft patients, the cleft site did not appear to impact the morphology of first molars. CONCLUSION: Unilateral clefting did not affect the size and shape of molars; however, characteristic ethnicity-based differences were in fact identified. The results are relevant for orthodontic treatment with preadjusted appliances, and prosthetic CAD/CAM restorations.