Introduction Microbiome from a “healthy cohort” is used as a reference for comparison to cases and intervention. However, the studies with cohort‐based clinical research have not sufficiently accounted for the multistability in oral microbial community. The screening is limited to phenotypic features with marked variations in microbial genomic markers. Herein, we aimed to assess the stability of the oral microbiome across time from an intervention‐free “healthy” cohort. Methods We obtained 33 supragingival samples of 11 healthy participants from the biobank. For each participant, we processed one sample as baseline (T0) and two samples spaced at 1‐month (T1) and 3‐month (T2) intervals for 16S ribosomal RNA gene sequencing analysis. Results We observed that taxonomic profiling had a similar pattern of dominant genera, namely, Rothia, Prevotella, and Hemophilus, at all time points. Shannon diversity revealed a significant increase from T0 (p < .05). Bray Curtis dissimilarity was significant (R = −.02, p < .01) within the cohort at each time point. Community stability had negative correlation to synchrony (r = −.739; p = .009) and variance (r = −.605; p = .048) of the species. Clustering revealed marked differences in the grouping patterns between the three time points. For all time points, the clusters presented a substantially dissimilar set of differentially abundant taxonomic and functional biomarkers. Conclusion Our observations indicate towards the presence of multistable states within the oral microbiome in an intervention‐free healthy cohort. For a conclusive and meaningful long‐term reference, dental clinical research should account for multistability in the personalized therapy approach to improve the identification and classification of reliable markers.

Low dose and accessibility have increased the application of cone beam computed tomography (CBCT). Often serial images are captured for patients to diagnose and plan treatment in the craniofacial region. However, CBCT images are highly variable and lack harmonious reproduction, especially in the head’s orientation. Though user-defined orientation methods have been suggested, the reproducibility remains controversial. Here, we propose a landmark-free reorientation methodology based on principal component analysis (PCA) for harmonious orientation of serially captured CBCTs. We analyzed three serial CBCT scans collected for 29 individuals who underwent orthognathic surgery. We first defined a region of interest with the proposed protocol by combining 2D rendering and 3D convex hull method, and identified an intermediary arrangement point. PCA identified the y-axis (anterioposterior) followed by the secondary x-axis (transverse). Finally, by defining the perpendicular z-axis, a new global orientation was assigned. The goodness of alignment (Hausdorff distance) showed a marked improvement (> 50%). Furthermore, we clustered cases based on clinical asymmetry and validated that the protocol was unaffected by the severity of the skeletal deformity. Therefore, it could be suggested that integrating the proposed algorithm as the preliminary step in CBCT evaluation will address a fundamental step towards harmonizing the craniofacial imaging records.

ObjectivesThe use of 16S ribosomal RNA gene sequencing analyses has rapidly increased in clinical oral studies. However, cohort-based clinical research has not sufficiently accounted for the periodic stability in oral microbiota. Herein, we aimed to assess the stability of the oral microbiome across time from an intervention-free “healthy” cohort. Materials and MethodsWe obtained 33 supragingival samples of 11 healthy participants from the biobank. For each participant, we processed one sample as baseline (T0) and two samples spaced at monthly (T1) and quarterly (T2) intervals for 16S ribosomal RNA gene sequencing analysis. ResultsWe observed that taxonomic profiling had a similar pattern of dominant genera, namely Rothia, Prevotella, and Hemophilus, at all-time points. Shannon diversity revealed a significant increase from T0 (p<0.05). Bray Curtis dissimilarity was significant (R=-0.02, p<0.01) within the cohort at each time point. Clustering revealed marked differences in the grouping patterns between the three-time points. For all time points, the clusters presented a substantially dissimilar set of differentially abundant taxonomic and functional biomarkers. ConclusionOur observations confirmed presence of periodically different stable states within the oral microbiome in an intervention-free healthy cohort. Accounting for multi-stability will improve the understanding of future research and facilitate identifying and classifying the reliable markers of diseased, healing, healed, and healthy states.Clinical relevanceThe high periodic variation within a healthy cohort demonstrated the presence of multiple stable states within an individual. Clinical research using RNA gene sequencing for comparison should adopt microbiome specific selection criteria for careful classification of a health-associated group.

Low dose and accessibility have increased the application of cone beam computed tomography (CBCT). Often serial images are captured for patients to diagnose and plan treatment in the craniofacial region. However, CBCT images are highly variable and lack harmonious reproduction, especially in the head's orientation. Though user-defined orientation methods have been suggested, the reproducibility remains controversial. Here, we propose a landmark-free reorientation methodology based on principal component analysis (PCA) for harmonious orientation of serially captured CBCTs. We analyzed three serial CBCT scans collected for 29 individuals who underwent orthognathic surgery. We first defined a region of interest with the proposed protocol by combining 2D rendering and 3D convex hull method, and identified an intermediary arrangement point. PCA identified the y-axis (anterioposterior) followed by the secondary x-axis (transverse). Finally, by defining the perpendicular z-axis, a new global orientation was assigned. The goodness of alignment (Hausdorff distance) showed a marked improvement (> 50%). Furthermore, we clustered cases based on clinical asymmetry and validated that the protocol was unaffected by the severity of the skeletal deformity. Therefore, it could be suggested that integrating the proposed algorithm as the preliminary step in CBCT evaluation will address a fundamental step towards harmonizing the craniofacial imaging records.

This case report describes a successful orthodontic treatment with maxillary expansion by using miniscrew-assisted rapid palatal expander (MARPE) and molar intrusion with mini-implants. A 22-year-old woman had an anterior open bite. It was a big complaint that she couldn't chew with her anterior teeth. After maxillary expansion, active maxillary molar intrusion was performed for bite closure. Due to anterior spacing and edge bite, space closure was done by using mini-implants, though she had a prominent chin. The total treatment period was 28 months. Active molar intrusion can guarantee bite closure, stable anterior overbite, and occlusion in skeletal Class I patients. However, the clinician must beware of the counter-clockwise rotation of the mandible and following facial change.