Orthodontic Treatment Need and the Psychosocial Impact of Malocclusion in 12-Year-Old Hong Kong Children.

OBJECTIVES: To determine the prevalence of orthodontic treatment need in 12-year-old children in Hong Kong and its relationship with the psychosocial impact of malocclusion and to assess their associations with sociodemographic factors. MATERIALS AND METHODS: A random sample of 687 12-year-old children was recruited from 45 secondary schools in Hong Kong. Orthodontic treatment need was assessed on study models by five indices: the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC), the Aesthetic Component of the IOTN (IOTN-AC), the Dental Aesthetic Index (DAI), the Index of Complexity Outcome and Need (ICON), and the Peer Assessment Rating (PAR). The psychosocial impact of malocclusion on participants and sociodemographic factors were obtained from a questionnaire. Logistic regression was used to examine the correlations between treatment need and the psychosocial impact of malocclusion as well as their associations with sociodemographic factors. RESULTS: The final number of participants was 667 (339 boys and 328 girls, participation rate 667/687 = 97.1%). The prevalence of orthodontic treatment need varied depending on the indices used (10.9-47.8%), but significant correlations were found among the five indices (p < 0.01). The uptake of treatment among the cohort was 2.3%. Boys had higher IOTN-DHC (p < 0.05), DAI (p < 0.05), and PAR (p = 0.05) scores than girls. IOTN-AC was significantly associated with the psychosocial impact of malocclusion (p < 0.05). Parents' level of education and household income were not significantly associated with either treatment need or the psychosocial impact of malocclusion (p > 0.05). CONCLUSION: The need for orthodontic treatment in 12-year-old children in Hong Kong remained high, and the uptake of treatment was low. Boys had a higher normative treatment need than girls. Among the five indices, IOTN-AC appears to be the best indicator of the psychosocial impact of malocclusion.

Mechanical and biological evaluations of novel electrospun PLLA composite scaffolds doped with oxide ceramics.

The objective of this study is to evaluate the in vitro performance of the novel electrospun composite scaffolds that are made of 10% PLLA in binary solvents (75 vol% dichloromethane: 25 vol% acetone) doped with 0.1 wt% of oxide ceramic powders (Hafnium dioxide (HfO2), titanium dioxide (TiO2), zirconium dioxide (ZrO2) and silicon dioxide (SiO2)). These composite scaffolds were characterized microscopically (SEM, TEM and EDX), mechanically (Vickers hardness and tensile strength) and in in vitro cell studies (biomineralization, protein absorption, and cytocompatibility) with MC3T3 pre-osteoblasts. The combination of PLLA polymer with oxide ceramics was indicated to be able to provide osteogenic properties that can enhance osteoblastic cell proliferation. In particular, results from the study demonstrated that the presence of zirconia and hafnia in the PLLA/ZrO2 and PLLA/HfO2 composite scaffolds could increase cell proliferation, protein adsorption and biomineralization properties significantly more than other two groups' scaffolds. PLLA/TiO2 provided the best mechanical strength than others (p < 0.05). To conclude, the novel composite scaffolds, which are promising biomaterials for tissue engineering, could be manufactured easily by electrospinning techniques.

A Comparative Analysis of Tooth Size Discrepancy between Male and Female Subjects Presenting with a Class I Malocclusion.

OBJECTIVES: To evaluate the tooth size discrepancy and Bolton's ratios between male and female subjects with a Class I malocclusion. MATERIALS AND METHODS: The digital e-models of 100 male and 100 female 12-year-old southern Chinese children with a Class I malocclusion were selected. The mesiodistal widths from permanent first molar to the contralateral side first molar of the upper and lower dentitions were measured. Differences between the tooth size discrepancy, together with the anterior and overall Bolton's ratios between male and female subjects, were assessed using a two-sample t-test. A paired t-test was used to determine differences between antimetric pairs of teeth within the same arch. RESULTS: Females had statistically significant smaller teeth than males (P < 0.05) except the upper left and lower left lateral incisor and lower left and right central incisors. The mean values of anterior Bolton's ratios for males and females were 77.04 and 77.03, respectively (P > 0.05), while the mean values of overall Bolton's ratios of male and female are 90.48 and 90.65, respectively (P < 0.05). The clinical significant differences (Cohen's d > 0.2) for contralateral tooth size were shown on the maxillary canines, lateral incisors, and central incisors of males; and mandibular canines and lateral incisors of females. CONCLUSIONS: Southern Chinese females presenting with Class I malocclusions have smaller mesiodistal tooth dimensions compared to males. Both males and females presented several tooth size asymmetries. There are no statistical differences in anterior and overall Bolton's ratios between the genders.

Digital Models as an Alternative to Plaster Casts in Assessment of Orthodontic Treatment Outcomes.

OBJECTIVE: This study aimed to compare the use of digital models and plaster casts in assessing the improvement in occlusion following orthodontic treatment. MATERIALS AND METHODS: Digital models and plaster casts of 39 consecutive patients at pre- and posttreatment stages were obtained and assessed using the Peer Assessment Rating (PAR) index and the Index of Complexity and Treatment Need (ICON). PAR and ICON scores were compared at individual and group levels. Categorization of improvement level was compared using Kappa (κ) statistics. RESULTS: There was no significant difference in neither PAR scores (p > 0.05) nor ICON scores (p > 0.05) between digital and plaster cast assessments. The Intraclass Correlation Coefficient (ICC) values for changes in PAR and ICON scores were excellent (ICC > 0.80). Agreement of ratings of occlusal improvement level between digital and plaster model assessments was 0.83 (κ) for PAR and 0.59 (κ) for ICON, respectively. CONCLUSION: The study supported the use of digital models as an alternative to plaster casts when assessing changes in occlusion at the 'individual patient' level using ICON or PAR. However, it could not fully support digital models as an alternate to plaster casts at 'the group level' (as in the case of clinical audit/research).

Dental Arch Relationships and Reverse Headgear Effects in Southern Chinese Patients with Unilateral Cleft Lip and Palate: A Retrospective Study.

OBJECTIVE: To evaluate the severity of the dental arch relationships and the treatment outcomes of reverse headgear (RHG) in southern Chinese patients with unilateral cleft lip and palate (UCLP). DESIGN: A retrospective study. SETTING: Faculty of Dentistry, The University of Hong Kong. PATIENTS: Thirty-eight UCLP patients with complete records. Among them, 14 were later treated with RHG (RHG group) and 24 were under review (non-RHG group) before definitive orthodontic or in conjunction with orthognathic surgery. INTERVENTIONS: Study models at T1 (aged 9.4 ± 0.4 years old), prebone grafting and before any orthodontic treatment started; T2 (aged 11.3 ± 0.6 years old), after bone grafting, and RHG treatment (RHG group) or under review (non-RHG group); and T3 (aged 15.3 ± 3.2 years old), pretreatment of definitive orthodontic or in conjunction with orthognathic surgery. MAIN OUTCOME MEASURES: With satisfactory intra- and interexaminer agreement proven by the kappa value, the dental arch relationships of the study models at T1, T2, and T3 were assessed by a solo calibrated examiner using the GOSLON Yardstick. RESULTS: The median GOSLON score for southern Chinese patients with UCLP at T1 was 4.0. Sixty percent of the patients were categorized as "poor" at T1. RHG significantly improved dental arch relationships from T1 to T2, and the improvement was maintained until T3 assessed by the GOSLON Yardstick. CONCLUSIONS: The dental arch relationships in southern Chinese UCLP patients at 8 to 10 years old are unfavorable. RHG treatment shows positive effects in improving the dental arch relationships in UCLP patients, as assessed by the GOSLON Yardstick.

Frontal facial proportions of 12-year-old southern Chinese: a photogrammetric study.

This study aimed to establish norm values for facial proportion indices among 12-year-old southern Chinese children, to determine lower facial proportion, and to identify gender differences in facial proportions.A random population sample of 514 children was recruited. Fifteen facial landmarks were plotted with ImageJ (V1.45) on standardized photos and 22 Facial proportion index values were obtained. Gender differences were analyzed by 2-sample t-test with 95% confidence interval. Repeated measurements were conducted on approximately 10% of the cases.The rate of adopted subjects was 52.5% (270/514). Intraclass correlation coefficient values (ICC) for intra- examiner reliability were >0.87. Population facial proportion index values were derived. Gender differences in 11 of the facial proportion indices were evident (P < 0.05).Upper face-face height (N- Sto/ N- Gn), vermilion height (Ls-Sto/Sto-Li), upper face height-biocular width (N-Sto/ExR-ExL) and nose -face height (N-Sn/N-Gn) indices were found to be larger among girls (P < 0.01). Males had larger lower face-face height (Sn -Gn/ N-Gn), mandibulo-face height (Sto-Gn/N-Gn), mandibulo-upper face height (Sto-Gn/N-Sto), nasal (AlR-AlL/N-Sn), upper lip height-mouth width (Sn-Sto/ChR-ChL), upper lip-upper face height (Sn-Sto/N-Sto) and upper lip-nose height (Sn-Sto/N-Sn) indices (P < 0.05).Population norm of facial proportion indices for 12-year-old Southern Chinese were derived and mean lower facial proportion were obtained. Sexual dimorphism is apparent.

Change of mandibular position during two-phase orthodontic treatment of skeletal class II in the Chinese population.

The aim of this study was to evaluate the change in mandibular position during a two-phase orthodontic treatment of skeletal Class II malocclusion. Thirty consecutively treated Chinese male adolescents who had undergone two-phase treatment with Herbst appliance and fixed appliance and fulfilled the specific selection criteria were sampled. Cephalograms taken at T0 (before treatment), T1 (at the end of functional appliance treatment), and T2 (at the end of fixed appliance treatment) were analyzed. The change in sagittal positioning of the mandible was 6.8 ± 3.44 mm in phase I (T0-T1), 0.4 ± 2.79 mm in phase II (T1-T2), and 7.2 ± 4.61 mm in total. The mandible came forward in 100% of the patients at T1. In phase II, it came forward in one-third (positive group) remained unchanged in one-third (stable group) and went backward in one-third (negative group) of the patients. At T2, it came forward twice as much in the positive group compared to the negative group. Mandibular length was significantly increased in 100% of the patients in both phases. In conclusion, during the treatment with functional appliance, the mandibular prognathism increases in all patients, whereas during the treatment with fixed appliance there is no significant change in mandibular prognathism.

The role of traditional Chinese medicines in osteogenesis and angiogenesis.

The article aims to review various Traditional Chinese Medicines (TCMs) with both osteogenic and angiogenic effects, alone and in combination, and to consider whether these TCMs promote osteogenesis via angiogenesis and vascular endothelial growth factor (VEGF). Each of the TCMs involving in osteogenesis was searched through PubMed and CBMdisc using its Latin name and English name, and keywords such as 'osteogenesis', 'bone', 'osteoblast', 'angiogenesis', 'VEGF' were used. A total of 241 articles were screened from PubMed and CBMdisc. The articles were only chosen if they discussed the relationship of the TCMs with bone formation and/or angiogenesis. Twenty-seven articles were chosen, of which 16 were in English and 11 were in Chinese with English abstract. As a result, the TCMs (Danshen or Salvia miltiorrhiza Bunge, Danggui or Angelica sinensis, Astragalus membranaceus Bunge or Huangqi, and Ge Gan or Puerarin radix) that have a relationship with both osteogenesis and angiogenesis were screened out. It is found that the aforementioned TCMs enhance angiogenesis and osteogenesis. They show a positive effect on bone formation, and the possible mechanisms may be related to their ability to promote angiogenesis via an effect on substances such as VEGF.

Tratamento de más oclusões de Classe II graves com aparelhos funcionais removíveis e ortodônticos sequenciais: um caso para a avaliação do MOrthRCSEd / Management of severe Class II malocclusion with sequential removable functional and orthodontic appliances: a case for MOrthRCSEd examination

INTRODUÇÃO: o aparelho funcional é uma forma eficaz de tratar as más oclusões de Classe II esqueléticas em crianças e adolescentes. Um protocolo de avanço mandibular progressivo de 12 meses já demonstrou ser capaz de aumentar o crescimento condilar e melhorar o prognatismo mandibular utilizando o aparelho de Herbst. OBJETIVO: relatar o caso clínico (apresentado como um dos requisitos para aprovação no Exame de Ortodontia para Filiação ao Royal College of Surgeons de Edimburgo*) de uma menina chinesa de 11 anos de idade, com 11mm de sobressaliência, tratada na Fase I da terapia de modificação do crescimento, ao longo de 12 meses, utilizando o aparelho Twin Block com um expansor palatal Hyrax e um extrabucal de puxada alta, em um protocolo de avanço mandibular progressivo, seguido pela Fase II da terapia, com um aparelho Edgewise pré-ajustado.

INTRODUCTION: Functional appliances are an effective way of treating skeletal Class II malocclusion in children and adolescents. A 12 month step-wise mandibular advancement protocol has been proved to enhance the condylar growth and improve the mandibular prognathism using Herbst appliance. OBJECTIVES: The following case report documented a 11 year-old Chinese girl with 11 mm overjet treated by a Phase I 12-month growth modification therapy using Twin Block appliance with Hyrax palatal expander and high pull headgear in a step-wise mandibular advancement protocol followed by a Phase II preadjusted Edgewise appliance therapy. This is one of the cases submitted for the Membership of Orthodontics Examination of the Royal College of Surgeons of Edinburgh.

Analysis of genetic polymorphisms in skeletal Class I crowding.

INTRODUCTION: Dental crowding is a problem for both adolescents and adults in modern society. The purpose of this research was to identify single nucleotide polymorphisms (SNPs) responsible for crowding in subjects with skeletal Class I relationships. METHODS: The case subjects consisted of healthy Chinese people living in Hong Kong with skeletal Class I relationships and at least 5 mm of crowding in either arch. The control subjects met the same requirements but lacked crowding or spacing. SNP genotyping was performed on the MassARRAY platform. The chi-square test was used to compare genotype and allele type distributions between the case and the control groups. Logistic regression was used to calculate odds ratios with 95% confidence intervals, and the effects of age and sex for each SNP. Analyses of linkage disequilibrium and haplotype associations between SNPs were performed with software. RESULTS: Five SNPs were found to be significantly different in genotype or allele type distributions. SNP rs372024 was significantly associated with crowding (P = 0.004). Two SNPs, rs3764746 and rs3795170, on the EDA gene were found to be associated marginally. SNPs rs1005464 and rs15705 also exhibited marginal association with crowding. The effects of associated SNPs remained significant after adjustments for age and sex factors. CONCLUSIONS: This study suggests an association for the genes EDA and XEDAR in dental crowding in the Hong Kong Chinese population.

Sagittal and vertical occlusal cephalometric analyses of Pancherz: Norms for Chinese children.

INTRODUCTION: The aims of this research were to establish norms for the sagittal and vertical occlusal cephalometric analyses of Pancherz for Chinese children and compare them with those of a matched white sample. METHODS: The material comprised lateral cephalograms of a random sample of 405 southern Chinese children (age, 12 years; 200 boys, 205 girls) and an additional sample of 86 British white children (age, 12 years; 43 boys, 43 girls) in Hong Kong. The radiographs were digitized twice. RESULTS: Statistically significant sex differences were found for 9 of 11 parameters in the sagittal occlusal analysis, and 6 of 10 in the vertical occlusal analysis in the Chinese sample, whereas there were no sex differences in the sagittal occlusal analysis and only 2 differences in the vertical occlusal analysis in the white sample. Statistically significant ethnic differences were found for 5 parameters in boys and 8 in girls of the 11 parameters in the sagittal analysis. For the vertical analysis, 7 of 10 parameters in both sexes differed significantly. CONCLUSIONS: For the sagittal and vertical occlusal analyses of Pancherz, separate sex-specific standards are needed for Chinese and white children.

The Hybrid Orthodontic Treatment System (HOTS).

This paper describes the Hybrid Orthodontic Treatment System (HOTS), an innovative method used in first premolar extraction cases. It comprises the following three components: (1) a miniscrew, (2) dual-dimension wires, and (3) multiloop edgewise archwires. HOTS consists of four clearly defined treatment steps: (1) setup, (2) leveling, (3) separate but simultaneous anterior and canine teeth retraction, and (4) final adjustment. HOTS achieves a predictable treatment outcome with a shorter treatment time.

Identification of the chondrogenic pathway in the mandibular condylar cartilage.

To identify genetic expression of mandibular condylar cartilage during natural growth and under mechanical strain as a result of mandibular advancement. One hundred and forty four 35 days old female Sprague-Dawley rats were sacrificed on 8 different experimental days. Total RNA was extracted for oligonucleotide microarray gene chips containing 15,923 transcripts. Sixteen genes representing the chondrogenesis pathway were identified. Five of them were novel and have never been identified in mandibular condyles before. Quantitative analysis using real-time PCR revealed that these genes were involved in different stages in chondrogenesis and played an important role in condylar growth.

Versatility of skeletal anchorage in orthodontics.

The purpose of this article is to update clinicians on the current concepts and versatile uses and clinical applications of skeletal anchorage in orthodontics. Topics discussed include clinical indications, implant types, surgical sites, biomechanics, treatment time, and treatment outcomes.

Use of miniscrews and miniplates in orthodontics.

Paradigms have started to shift in the orthodontic world since the introduction of mini-implants in the anchorage armamentarium. For example, miniscrews have allowed the management of wider discrepancies than those treatable by conventional biomechanics because force can be applied directly from the bone-borne anchor unit. Therefore, miniscrews not only free orthodontists from anchorage-demanding cases, but they also enable clinicians to have good control over tooth movement in 3 dimensions. This review will illustrate the versatility of skeletal anchorage provided by mini-implants in the correction of malocclusion, focusing on orthodontic or orthopedic movements in the 3 spatial planes. Adjunctive orthodontic treatments in adult periodontal conditions and treatment for impacted teeth with the aid of miniscrews will also be discussed.

Maxillary second molar extractions in orthodontic treatment.

This article is a review of the rationales, indications, methods, and effects of orthodontic treatment with maxillary second molar extractions. In addition to the patient's malocclusion, specific considerations about the status and position of the maxillary second and third molars should be taken into account. In recent years, the development of temporary anchorage devices, in addition to extraoral traction and intraoral distalization appliances, has become another armamentarium in the distalization of the maxillary posterior teeth, which may affect the selection of teeth to be extracted from second to third molars. In conclusion, extraction of maxillary second molars is a viable option in selected cases at present, but it is important to understand the indications and limitations of this treatment choice.