An abrupt regime shift of bacterioplankton community from weak to strong thermal pollution in a subtropical bay.

Thermal pollution from the cooling system of the nuclear power plants greatly changes the environmental and the ecological conditions of the receiving marine water body, but we know little about their impact on the steady-state transition of marine bacterioplankton communities. In this study, we used high-throughput sequencing based on the 16S rRNA gene to investigate the impact of the thermal pollution on the bacterioplankton communities in a subtropical bay (the Daya Bay). We observed that thermal pollution from the cooling system of the nuclear power plant caused a pronounced thermal gradient ranging from 19.6°C to 24.12°C over the whole Daya Bay. A temperature difference of 4.5°C between the northern and southern parts of the bay led to a regime shift in the bacterioplankton community structure. In the three typical scenarios of regime shifts, the steady-state transition of bacterioplankton community structure in response to temperature increasing was more likely consistent with an abrupt regime shift rather than a smooth regime or a discontinuous regime model. Water temperature was a decisive factor on the regime shift of bacterioplankton community structure. High temperature significantly decreased bacterioplankton diversity and shifted its community compositions. Cyanobium and Synechococcus of Cyanobacteria, NS5 marine group of Bacteroidota, and Vibrio of Gammaproteobacteria were found that favored high temperature environments. Furthermore, the increased water temperature significantly altered the community assembly of bacterioplankton in Daya Bay, with a substantial decrease in the proportion of drift and others, and a marked increase in the proportion of homogeneous selection. In summary, we proposed that seawater temperature increasing induced by the thermal pollution resulted in an abrupt regime shift of bacterioplankton community in winter subtropical bay. Our research might broad our understanding of marine microbial ecology under future conditions of global warming.

Biomechanical Considerations in the Orthodontic Treatment of a Patient with Stabilised Stage IV Grade C Generalised Periodontitis: A Case Report.

Orthodontic treatment of periodontally compromised patients presents unique challenges, including controlling periodontal inflammation, applying appropriate force, designing an effective dental anchorage, and maintaining treatment results. Deteriorated periodontal support leads to alterations in the biological responses of teeth to mechanical forces, and thus orthodontists must take greater care when treating patients with periodontal conditions than when treating those with a good periodontal status. In this article, we report the case of a 59-year-old woman with stabilised Stage IV grade C generalised periodontitis characterised by pathological tooth migration (PTM). The assessment, planning, and treatment of this patient with orthodontic fixed appliances is described. Moreover, the anchorage planning and biomechanical considerations are detailed. Specific orthodontic appliances were employed in this case to produce force systems for achieving precise tooth movement, which included a cantilever, mini-screws, and a box loop. Careful application of those appliances resulted in satisfactory aesthetic and functional orthodontic outcomes in the patient. This case highlights the importance of multidisciplinary collaboration in the treatment of patients with severe periodontitis and the potential for tailored biomechanical approaches in orthodontic treatment to furnish good outcomes.

Radiographic Imaging for the Diagnosis and Treatment of Patients with Skeletal Class III Malocclusion.

Skeletal Class III malocclusion is one type of dentofacial deformity that significantly affects patients' facial aesthetics and oral health. The orthodontic treatment of skeletal Class III malocclusion presents challenges due to uncertainties surrounding mandibular growth patterns and treatment outcomes. In recent years, disease-specific radiographic features have garnered interest from researchers in various fields including orthodontics, for their exceptional performance in enhancing diagnostic precision and treatment effect predictability. The aim of this narrative review is to provide an overview of the valuable radiographic features in the diagnosis and management of skeletal Class III malocclusion. Based on the existing literature, a series of analyses on lateral cephalograms have been concluded to identify the significant variables related to facial type classification, growth prediction, and decision-making for tooth extractions and orthognathic surgery in patients with skeletal Class III malocclusion. Furthermore, we summarize the parameters regarding the inter-maxillary relationship, as well as different anatomical structures including the maxilla, mandible, craniofacial base, and soft tissues from conventional and machine learning statistical models. Several distinct radiographic features for Class III malocclusion have also been preliminarily observed using cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI).

Association between occlusal features and masticatory function in Hong Kong preschool children: a survey with one-year longitudinal follow-up.

BACKGROUND: Mastication is important for breaking down food, aiding swallowing and nutrients absorption, and is therefore fundamental to a child's development. Studies have shown poor masticatory function to be associated with younger age and presence of caries. However, studies of the association between masticatory function and malocclusion yielded contradictory results. The aim of this study is therefore to investigate the association between three-dimensional occlusal features with masticatory function, among preschool children in Hong Kong. METHODS: Self-administered questionnaires on masticatory function in three domains, namely general chewing difficulty, requiring help when eating different food types and increased preference for soft food were completed by parents. Information on non-nutritive sucking habits and basic demographics were also collected in the questionnaire. Clinical examinations were conducted to record three-dimensional occlusal features and presence of caries. Baseline investigations and one-year follow-ups were undertaken for 1,566 and 996 preschool children. Association of poor masticatory function with occlusal features, sucking habits and caries was investigated using chi-squared tests. Binomial logistic regressions were then carried out incorporating any significant factors identified. Longitudinal analysis of the one-year follow-up data was carried out to investigate whether improved occlusal features, sucking habits and caries resulted in better masticatory function. RESULTS: In the cross-sectional study, the first domain of general chewing difficulty was associated with caries and thumb/digit sucking. The second domain of requiring help when eating different food types was associated with the male sex, younger age, caries and pacifier use. The last domain of increased preference for soft foods was associated with caries and thumb/digit sucking. Occlusal features, including abnormal overjet and unilateral permanent molars not in contact, were significantly associated with poor masticatory function in the bivariate analyses, but were not significant in the logistic regressions. In the longitudinal analysis, general chewing difficulty was found to improve in those of older age and those with resolved anterior crossbite. Less help was required to eat meat in those with fewer caries. Similarly, less help was required to eat food containing bones in those with reduced pacifier use. Preferences for eating soft foods was reduced in those who developed a normal overjet. CONCLUSIONS: The study identified significant relationships between masticatory difficulties and factors associated with age, gender, active caries, and non-nutritive oral habits such as thumb/digit sucking and pacifier use. Younger children and males required more assistance with certain food types. Active caries and thumb/digit sucking habits contributed to general masticatory difficulties and preference for soft foods. The one-year follow-up indicated that improvement in masticatory function varies across age cohorts and were associated with improved occlusal features, such as resolution of anterior crossbite and normalized overjet, reduced pacifier use, and a decrease in the number of decayed teeth.

Improvement of parents' oral health knowledge by a school-based oral health promotion for parents of preschool children: a prospective observational study.

BACKGROUND: Parents of preschool children have inadequate oral health knowledge in Hong Kong. Parents play a critical role in preschool children's dietary patterns and oral health behaviors. A school-based oral health promotion (OHP) for parents of preschoolers was developed and investigated. OBJECTIVES: The objective of this study was to evaluate effects of the school-based OHP for parents of preschool children on parents' oral health knowledge and preschool children's early childhood caries (ECC). MATERIALS AND METHODS: This was a quasi-experimental study. Parents of preschool children were divided into the intervention group (IG) and the control group (CG) according to their own selection. Parents in the IG participated in a structured school-based OHP workshop, while those in the CG did not attend the OHP workshop. Parents in both groups were invited to complete a questionnaire assessing their oral health knowledge before (T0), one month after (T1), and twelve months after (T2) the OHP workshop. Preschool children's caries was examined via dmft score at T0 and T2. RESULTS: Parents' oral health knowledge was negatively correlated with preschool children's dmft scores (R = -0.200, P < 0.001). Oral health knowledge was significantly improved in IG (P < 0.001) but not in CG (P = 0.392) at T1. Both groups experienced a significant improvement in oral health knowledge from T0 to T2 (P < 0.001). Parents' oral health knowledge in the IG was significantly higher compared to the CG at T1 (P < 0.001), but difference in the scores at T2 between the two groups showed no significant difference (P = 0.727). No significant difference was found in changes in children's dmft score from T0 to T2 between the IG and CG (p = 0.545). CONCLUSION: Preschool children's high ECC is associated with the limited oral health knowledge of their parents. The school-based OHP workshop for parents increased parents' oral health knowledge within one month. This positive effect was maintained for twelve months and can be extended to a larger scale in the school setting.

Application of Artificial Intelligence in Orthodontics: Current State and Future Perspectives.

In recent years, there has been the notable emergency of artificial intelligence (AI) as a transformative force in multiple domains, including orthodontics. This review aims to provide a comprehensive overview of the present state of AI applications in orthodontics, which can be categorized into the following domains: (1) diagnosis, including cephalometric analysis, dental analysis, facial analysis, skeletal-maturation-stage determination and upper-airway obstruction assessment; (2) treatment planning, including decision making for extractions and orthognathic surgery, and treatment outcome prediction; and (3) clinical practice, including practice guidance, remote care, and clinical documentation. We have witnessed a broadening of the application of AI in orthodontics, accompanied by advancements in its performance. Additionally, this review outlines the existing limitations within the field and offers future perspectives.

Radiomics Analysis in Characterization of Salivary Gland Tumors on MRI: A Systematic Review.

Radiomics analysis can potentially characterize salivary gland tumors (SGTs) on magnetic resonance imaging (MRI). The procedures for radiomics analysis were various, and no consistent performances were reported. This review evaluated the methodologies and performances of studies using radiomics analysis to characterize SGTs on MRI. We systematically reviewed studies published until July 2023, which employed radiomics analysis to characterize SGTs on MRI. In total, 14 of 98 studies were eligible. Each study examined 23-334 benign and 8-56 malignant SGTs. Least absolute shrinkage and selection operator (LASSO) was the most common feature selection method (in eight studies). Eleven studies confirmed the stability of selected features using cross-validation or bootstrap. Nine classifiers were used to build models that achieved area under the curves (AUCs) of 0.74 to 1.00 for characterizing benign and malignant SGTs and 0.80 to 0.96 for characterizing pleomorphic adenomas and Warthin's tumors. Performances were validated using cross-validation, internal, and external datasets in four, six, and two studies, respectively. No single feature consistently appeared in the final models across the studies. No standardized procedure was used for radiomics analysis in characterizing SGTs on MRIs, and various models were proposed. The need for a standard procedure for radiomics analysis is emphasized.

Effects of Low-Level Laser Therapy on Dentin Hypersensitivity in Periodontally Compromised Patients Undergoing Orthodontic Treatment: A Randomised Controlled Trial.

OBJECTIVES: This study aimed to assess the effects of low-level laser therapy (LLLT) on dentin hypersensitivity (DH) in periodontally compromised patients undergoing orthodontic treatment. METHODS: This triple-blinded randomised controlled trial included 143 teeth with DH from 23 periodontally compromised patients. Teeth on one side of the dental arch were randomly assigned to the LLLT group (LG), while those on the contralateral side were allocated to the non-LLLT group (NG). After orthodontic treatment commenced, patients' orthodontic pain (OP) perceptions were documented in pain diaries. DH was assessed chairside by a visual analogue scale (VASDH) at fifteen timepoints across the orthodontic treatment and retention. VASDH scores were compared among timepoints by the Friedman test, among patients with varying OP perceptions using the Kruskal-Wallis tests, and between the LG and NG with the Mann-Whitney U test. RESULTS: DH generally decreased over the observation (p < 0.001). The VASDH scores differed among patients with varying OP perceptions at multiple timepoints (p < 0.05). The generalized estimating equation model showed teeth in the LG had a significantly lower VASDH score than the NG at the 3rd month of treatment (p = 0.011). CONCLUSION: LLLT could be potentially beneficial in managing DH in periodontally compromised patients undergoing orthodontic treatment.

Dynamic alternations of RANKL/OPG ratio expressed by cementocytes in response to orthodontic­induced external apical root resorption in a rat model.

The aim of the present study was to investigate the alterations in the formation of cementocytes in response to orthodontic forces and to evaluate the contribution of these cells in the biological changes of tooth movement and associated root resorption. A total of 90 Sprague Dawley rats were randomly assigned to the control, high force, and low force groups. Intrusion forces of 10 and 50 g were applied on the rat molar to induce tooth intrusion. The tooth movement was observed from 0 to 14 days by micro­computed tomography, bone histometric analysis, tartrate­resistant acid phosphatase staining, as well as reverse transcription­quantitative PCR and immunofluorescence staining assays. The results suggested that under low force conditions, osteoclasts were distributed at a higher frequency on the bone side than on the root side. Under high force conditions, both sides suffered osteoclast infiltration. In the low force group, the cementocytes exhibited downregulated sclerostin (SOST) and osteoprotegerin (OPG) mRNA levels and a lower receptor activator of nuclear factor­κB ligand (RANKL)/OPG ratio over a certain period of time. The expression levels of these genes were lower compared with those of the osteocytes at each time­point. In the high force group, both cementocytes and osteocytes upregulated the SOST and RANKL/OPG ratio on days 7 and 14, while the cementocytes expressed higher levels of SOST mRNA than those noted in the osteocytes. These data suggested that cementocytes responded to the orthodontic force via modulation of the RANKL/OPG ratio and SOST expression. The biological response of cementocytes contributed to the mechanotransduction and homoeostasis of the roots under compression. Excessive forces may act as a negative factor of this regulatory role. These results expand our knowledge on the function of cementocytes.

3-Dimensional simulations and student learning in orthodontic education.

INTRODUCTION: The electronic dental model (e-model) is an example of a digital 3-dimensional technology to support inquiry-based learning in undergraduate dental education. As student perceptions of and engagement with e-models vary, it is uncertain whether these perceptions have implications for their learning processes and outcomes. MATERIALS AND METHODS: Third-year dental students (N = 40) completed a questionnaire to identify their perceptions of and preferences for model modalities. They were divided into three groups based on their preference: Preferring plaster models (Group 1); Preferring e-models (Group 2); No preference (Group 3). Students from three groups (N = 9) attended a hands-on digital occlusion evaluation workshop, and then completed a case-based diagnostic evaluation test using digital occlusion evaluation software. Camtasia Studio™ recorded real-time and on-screen data of the number of mouse-clicks and time spent. RESULTS: Students reported positive feedbacks on the use of e-models, and 72.5% of the students preferred combination use of e-models and plaster models. After attending the hands-on digital dental occlusion evaluation workshop, Group 2 scored higher on the diagnostic evaluation test (p < .05) and registered more mouse-clicks than Group 1 when evaluating the arch symmetry (p < .05). Group 2 registered fewer mouse-clicks than Group 3 during tooth size measurement (p < .05). There was no significant difference regarding the time used to answer the knowledge questions amongst the three groups. CONCLUSION: Undergraduate dental students indicated a generally high acceptance of e-models for their learning in orthodontics, and more prefer a blended approach. Students preferring e-models presented higher performance outcomes, which supports cognitive load theory regarding prior exposure to simulation-based environments.

Nasal asymmetry changes during growth and development in 6- to 12-year-old children with repaired unilateral cleft lip and palate: A 3D computed tomography analysis.

Repaired unilateral cleft lip and palate (UCLP) is often accompanied by the deformity and asymmetry of the nasal region. Three-dimensional analysis was performed to investigate the relationship between nasal soft- and hard-tissue asymmetries, as well as the changes in nasal asymmetry with age, among children with repaired UCLP (age: 6-12 years). Forty-seven patients were included in this study. Their computed tomography records were retrieved for analysis of the 3D asymmetry of 10 landmarks of the nasal soft and hard tissues. We observed that asymmetry was more severe in nasal hard tissues than in soft tissues, particularly in the sagittal dimension. Compared with patients aged 6-9 years old, patients aged 10 to 12 years old had significantly increased vertical asymmetry at the base of the alar groove (Gbase, p = 0.027) and the lateral point of the piriform aperture (LPA), (p < 0.001). The correlation between the LPA and the alar region was weak to moderate (r = 0.290 to 0.488). In conclusion, we found no evidence of growth and development in nasal hard-tissue asymmetry among 6- to 12-year-old children with repaired UCLP, except for the vertical dimension. Nasal soft tissue exhibited a more preferable symmetry than hard tissue, and this could be attributed to the compensatory growth of nasal soft tissue, particularly in the vertical and sagittal dimensions. The weak to moderate correlations between nasal soft-tissue asymmetry and hard-tissue asymmetry were observed in the three dimensions. Surgeons should consider these factors when repositioning the nasal alar and controlling the size of the nostrils.

Effects of low-level light therapy on dentin hypersensitivity: a systematic review and meta-analysis.

OBJECTIVE: To investigate the treatment efficacy of low-level light therapy on dentin hypersensitivity. MATERIALS AND METHODS: Following the PRISMA guideline, six electronic databases supplemented with bibliographies were searched till December 2020. Two reviewers performed the screenings independently with a reliability assessment. Studies fulfilling the pre-registered eligibility criteria were included for risk-of-bias assessment and data synthesis. RESULTS: Thirty-five articles ultimately informed this systematic review based on the eligibility criteria and underwent risk-of-bias assessment (ĸ = 0.86). Quantitative results were deduced by meta-analysis of 20 randomised controlled trials: LLLT showed favourable outcomes compared to placebos for immediate (SMD: 1.09, 95% CI: 0.47 to 1.70), interim (SMD: 1.32, 95% CI: 0.41 to 2.23), and persistent efficacies (SMD: 2.86, 95% CI: 1.98 to 3.74). However, substantial heterogeneity existed among included studies (I2: 64-95%). Regarding comparisons with other desensitising strategies, LLLT showed no significant benefits in DH alleviation over others except fluorides for interim efficacy (SMD: 0.31, 95% CI: 0.10 to 0.52) and persistent efficacy (SMD: 0.45, 95% CI: 0.03 to 0.86). CONCLUSIONS: This systematic review shows that LLLT has positive immediate, interim, and persistent DH-treatment efficacies compared with placebo. No superior treatment effects of LLLT were observed except fluoride agent use. Further studies are warranted-RCTs with low risk of bias, consistent technical settings, comprehensive assessments, and long follow-up periods. CLINICAL RELEVANCE: This systematic review bridges a critical research gap by analysing clinical evidence in the DH-alleviating efficacy of LLLT in comparison with placebo and other in-office desensitising strategies.

Anthropometric accuracy of three-dimensional average faces compared to conventional facial measurements.

This study aimed to evaluate and compare the accuracy of average faces constructed by different methods. Original three-dimensional facial images of 26 adults in Chinese ethnicity were imported into Di3DView and MorphAnalyser for image processing. Six average faces (Ave_D15, Ave_D24, Ave_MG15, Ave_MG24, Ave_MO15, Ave_MO24) were constructed using "surface-based registration" method with different number of landmarks and template meshes. Topographic analysis was performed, and the accuracy of six average faces was assessed by linear and angular parameters in correspondence with arithmetic means calculated from individual original images. Among the six average faces constructed by the two systems, Ave_MG15 had the highest accuracy in comparison with the conventional method, while Ave_D15 had the least accuracy. Other average faces were comparable regarding the number of discrepant parameters with clinical significance. However, marginal and non-registered areas were the most inaccurate regions using Di3DView. For MorphAnalyser, the type of template mesh had an effect on the accuracy of the final 3D average face, but additional landmarks did not improve the accuracy. This study highlights the importance of validating software packages and determining the degree of accuracy, as well as the variables which may affect the result.

Comprehensive Effects of Photobiomodulation Therapy as an Adjunct to Post-orthodontic Treatment Care: A Systematic Review.

PURPOSE: To evaluate the comprehensive effects of photobiomodulation (PBM) therapy on teeth after active orthodontic treatment. MATERIALS AND METHODS: This systematic review was conducted according to the PRISMA guidelines. Six databases were electronically searched and screened for eligible human and animal studies published up to August 2020. The risk of bias was assessed based on the Cochrane Handbook for Systematic Reviews of Interventions and Systematic Review Centre for Laboratory Experiment Tool. Two independent reviewers performed all procedures in duplicate. Any disagreement was resolved by discussion or consultation with a third reviewer. RESULTS: A total of 395 records were identified from the initial search up to August 2020. Following screening, 16 full-text articles were reviewed for eligibility (κ > 0.90), and ultimately 9 studies (3 clinical studies and 6 animal studies) were included in this review. The key outcomes observed were 'tooth position maintenance' and 'root resorption rehabilitation'. Two controlled clinical trials and two animal studies supported the preventive effects of PBM therapy on the relapse of post-orthodontic tooth positions, while the other two animal studies reported opposing findings. Regarding root resorption, all evidence supported the rehabilitation potential using PBM therapy for teeth that had undergone orthodontic tooth movement. There was a high risk of bias among studies, except for one randomised controlled trial. Due to the substantial heterogeneity among studies in terms of their types, participants, designs, PBM therapy settings and variables of interest, it was not possible to conduct a meta-analysis; therefore, a qualitative synthesis is presented. CONCLUSION: The quality of evidence for PBM therapy contributing to the maintenance of tooth position or improved dental health after orthodontic treatment remains low. There is considerable controversy over the effects of PBM therapy on orthodontic relapse. However, the use of PBM therapy after orthodontic treatment has promising effects for root resorption rehabilitation and is generally recommended.