Y Yang

The role of vascular endothelial growth factor in ossification

Osteogenesis and angiogenesis are two closely correlated processes during bone growth, development, remodelling and repair. Vascular endothelial growth factor (VEGF) is an essential mediator during the process of angiogenesis. Based on an extensive literature search, which was carried out using the PubMed database and the keywords of osteogenesis, VEGF, endochondral ossification and intramembranous ossification, this manuscript reviews the role of VEGF in ossification, with emphasis on its effect in endochondral and intramembranous ossification. Osteogenesis and angiogenesis are closely correlated processes. VEGF acts as an essential mediator during these processes. It not only functions in bone angiogenesis but also in various aspects of bone development.

The effectiveness of low-level diode laser therapy on orthodontic pain management: a systematic review and meta-analysis

To assess the effectiveness of diode low-level laser therapy (LLLT) for orthodontic pain control, a systematic and extensive electronic search for randomised controlled trials (RCTs) investigating the effects of diode LLLT on orthodontic pain prior to November 2014 was performed using the Cochrane Library (Issue 9, 2014), PubMed (1997), EMBASE (1947) and Web of Science (1956). The Cochrane tool for risk of bias evaluation was used to assess the bias risk in the chosen data. A meta-analysis was conducted using RevMan 5.3. Of the 186 results, 14 RCTs, with a total of 659 participants from 11 countries, were included. Except for three studies assessed as having a ‘moderate risk of bias’, the RCTs were rated as having a ‘high risk of bias’. The methodological weaknesses were mainly due to ‘blinding’ and ‘allocation concealment’. The meta-analysis showed that diode LLLT significantly reduced orthodontic pain by 39xa0% in comparison with placebo groups (Pu2009=u20090.02). Diode LLLT was shown to significantly reduce the maximum pain intensity among parallel-design studies (Pu2009=u20090.003 versus placebo groups; Pu2009=u20090.000 versus control groups). However, no significant effects were shown for split-mouth-design studies (Pu2009=u20090.38 versus placebo groups). It was concluded that the use of diode LLLT for orthodontic pain appears promising. However, due to methodological weaknesses, there was insufficient evidence to support or refute LLLT’s effectiveness. RCTs with better designs and appropriate sample power are required to provide stronger evidence for diode LLLT’s clinical applications.

The relationship between the cranial base and jaw base in a Chinese population

IntroductionThe cranial base plays an important role in determining how the mandible and maxilla relate to each other. This study assessed the relationship between the cranial base and jaw base in a Chinese population.MethodsThis study involved 83 subjects (male: 27; female: 56; age: 18.4u2009±u20094.2 SD years) from Hong Kong, who were classified into 3 sagittal discrepancy groups on the basis of their ANB angle. A cephalometric analysis of the angular and linear measurements of their cranial and jaw bases was carried out. The morphological characteristics of the cranial and jaw bases in the three groups were compared and assessments were made as to whether a relationship existed between the cranial base and the jaw base discrepancy.ResultsSignificant differences were found in the cranial base angles of the three groups. Skeletal Class II cases presented with a larger NSBa, whereas skeletal Class III cases presented with a smaller NSBa (Pu2009<u20090.001). In the linear measurement, skeletal Class III cases presented with a shorter NBa than skeletal Class I and II cases (Pu2009<u20090.01). There was a correlation between the cranial base angle NSBa and the SNB for the whole sample, (ru2009=u2009-0.523, Pu2009<u20090.001). Furthermore, correlations between SBaFH and Wits (ru2009=u2009-0.594, Pu2009<u20090.001) and SBaFH and maxillary length (ru2009=u2009-0.616, Pu2009<u20090.001) were more obvious in the skeletal Class III cases.ConclusionsThe cranial base appears to have a certain correlation with the jaw base relationship in a southern Chinese population. The correlation between cranial base and jaw base tends to be closer in skeletal Class III cases.

The effectiveness of low-level laser therapy as an adjunct to non-surgical periodontal treatment: a meta-analysis.

Background and Objectives Although low‐level laser therapy (LLLT) has been demonstrated to have a biomodulatory effect on periodontal tissue, no systematic review has exclusively addressed its effectiveness as an adjunct to non‐surgical periodontal treatment. This study aimed to evaluate whether an additional benefit exists for the application of LLLT compared with scaling and root planing (SRP) alone. Material and Methods An extensive search was conducted in the Cochrane Library (Issue 8, 2015), PubMed (1997) and EMBASE (1947) before August 2015 for randomized controlled trials (RCTs). The bias risk was assessed with the Cochrane tool for risk of bias evaluation. A meta‐analysis was performed using REVMAN 5.3. Results After independent screening of 354 initial records, eight publications (seven RCTs) were included. However, six were rated as ‘having a high risk of bias’ as a result of major methodological weakness in ‘allocation concealment’ and ‘blinding of key personnel’. Meta‐analysis showed that LLLT‐mediated SRP demonstrated significant short‐term benefits over SRP monotherapy in the improvement of the probing pocket depth (p = 0.0009 at 1 mo; p = 0.03 at 2 mo) and the level of interleukin‐1β in the gingival crevicular fluid (p = 0.01 at 1 mo). Nevertheless, LLLT failed to show significant additional intermediate‐term (3 and 6 mo) effects in terms of clinical parameters and alveolar bone density. Conclusion These findings indicated that LLLT showed only short‐term additional benefits after conventional SRP. Its long‐term effects remain unclear due to substantial methodological weaknesses and an insufficient number of current studies. Future RCTs with better designs and longer follow‐up periods are required to assess the effectiveness of LLLT as an adjunctive treatment strategy in patients with periodontal disease.

Edentulism and associated factors among community-dwelling middle-aged and elderly adults in China

OBJECTIVEnTo investigate the prevalence of self-reported edentulism and its associated risk factors among community-dwelling adults aged 45xa0years and older in China.nnnMATERIALS AND METHODSnData from the national baseline survey (2011-2012) of the China Health and Retirement Longitudinal Study (CHARLS) were used for this study (Nxa0=xa017xa0167). Bivariate and multivariate logistic regressions were conducted to assess the predictors of edentulism. Models 1 and 2 were based on the whole sample. Models 3 and 4 were based on the subsample (Nxa0=xa09933) from whom anthropometric and blood biomarker data were available.nnnRESULTSnThe prevalence of edentulism was 8.64% among Chinese adults aged 45 and above. As shown by Model 1, older age was a robust predictor for edentulism (odds ratio [OR]xa0=xa03.81 for people aged 55-64; ORxa0=xa011.22 for people aged 65-74; ORxa0=xa024.05 for people aged 75 and above). Other factors positively associated with edentulism included being female (ORxa0=xa01.25), rural residence (ORxa0=xa01.30), asthma (ORxa0=xa01.48), depression (ORxa0=xa01.20), reduced physical function (ORxa0=xa01.37) and current smoking status (ORxa0=xa01.36). People with higher educational levels (ORxa0=xa00.75 for people who can read and write; ORxa0=xa00.64 for people who obtained a junior high school education or above) and better-off economic status (ORxa0=xa00.80) were less likely to be edentate. The association between edentulism and age, educational level, economic status and physical function remained significant in Model 3, and in addition, being underweight appeared as another strong predictor (ORxa0=xa01.93).nnnCONCLUSIONSnThe estimated prevalence of edentulism and the identified associated factors will provide epidemiologic evidence for future research and interventions in the target population in China.

A Comparison of Three Viewing Media for Assessing Dental Arch Relationships in Patients With Unilateral Cleft Lip and Palate.

Objective To determine the repeatability and reproducibility of using three different viewing media to assess the outcomes of the dental arch relationships of patients with unilateral cleft lip and palate (UCLP) using the GOSLON Yardstick. Design The GOSLON Yardstick was used to rate the dental arch relationships of 29 patients with UCLP. Three experienced calibrated orthodontists rated the plaster study models, digital study models, and stereoscopic projected three-dimensional (3D) study models separately. There was a minimum of a 1-week interval between each rating session. All three rating sessions were repeated 1 month later. A linear weighted kappa statistic was performed to assess intrarater repeatability and inter-rater reproducibility, as well as the comparison between different viewing media using Kendalls Coefficient of Concordance (Kendalls W) statistic. Results Intra-rater repeatability was very good for all three viewing media (kappa = 0.83-0.92). Inter-rater reproducibility was good to very good across the three viewing media (kappa = 0.63-0.88). Agreements between plaster study models and digital study models or stereoscopic projected 3D study models were good to very good (kappa = 0.78-0.97 and kappa = 0.72-0.97, respectively), and a Kendalls W ranging from 0.86 to 0.92 (P < .001). Conclusions Stereoscopic projected 3D is an alternative method to assess the outcomes of dental arch relationships in patients with cleft lip and palate using the GOSLON Yardstick. It could also be used for viewing patient records, as it recovers the full 3D information captured at the time of the clinical examination.

Age-related effects on osteoclastic activities after orthodontic tooth movement

Objectives To elucidate the effects of age on the expression levels of the receptor activator of the nuclear factor-κB ligand (RANKL) and osteoclasts in the periodontal ligament during orthodontic mechanical loading and post-orthodontic retention. Materials and Methods The study included 20 male Sprague-Dawley rats, ten in the young group (aged four to five weeks) and ten in the adult group (aged 18 to 20 weeks). In each rat, the upper-left first molar was subjected to a seven-day orthodontic force loading followed by a seven-day retention period. The upper-right first molar served as a control. The amount of orthodontic tooth movement was measured after seven-day force application and seven-day post-orthodontic retention. The expression levels of RANKL and the tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts were evaluated on day 7 (end of mechanical force loading) and day 14 (after seven days of post-orthodontic retention). Statistical analysis was performed using the t-test, and significance was set at p < 0.05. Results There was no significant difference between the amount of tooth movement in the young group (0.96, standard deviation (sd) 0.30mm) and that in the adult group (0.80mm, sd 0.28) (p > 0.05) after the seven-day force application. On the compression side, the expression of RANKL and TRAP-positive osteoclasts in both the young and the adult groups increased after the application of force for seven days, and then decreased at the end of the seven-day retention period. However, by the end of the period, the expression of RANKL on the compression side dropped to the control level in the young group (p > 0.05), while it was still higher than that on the control side in the adult group (p < 0.05). The expression of RANKL on the compression side did not show significant difference between the young and the adult groups after seven-day force application (p > 0.05), but it was significantly higher in the adult group than that in the young group after seven-day post-orthodontic retention (p < 0.05). Similarly, the decreasing trend of TRAP-positive osteoclasts during the retention period in the adult group was less obvious than that in the young group. Conclusions The bone-resorptive activity in the young rats was more dynamic than that in the adult rats. The expression of RANKL and the number of osteoclasts in adult rats did not drop to the control level during the post-orthodontic retention period while RANKL expression and the number of osteoclasts in young rats had returned to the baseline. Cite this article: X. Li, M. Li, J. Lu, Y. Hu, L. Cui, D. Zhang, Y. Yang. Age-related effects on osteoclastic activities after orthodontic tooth movement. Bone Joint Res 2016;5:492–499. DOI: 10.1302/2046-3758.510.BJR-2016-0004.R2.

What are patients’ expectations of orthodontic treatment: a systematic review

BackgroundWhat patients expect to happen during treatment or benefit from the treatment might influence the subsequent factors such as treatment outcome, patient satisfaction, patient’s cooperation as well as compliance. The aim of this systematic review is to assess the role of patients’ expectations from orthodontic treatment.MethodsA systematic literature search of four databases Pubmed, Cochrane, Web of Science and PsychINFO was conducted following PRISMA guidelines. Studies reporting expectations regarding orthodontic treatment were selected and a narrative review was conducted. The quality of study was rated according to STROBE statements and the methodology as well as key findings were summarized.ResultsThirteen studies (14 papers) were finally included for analysis. Among them, only one was a randomized control trial, while the rest included one cohort study, two questionnaire-developments and ten cross-sectional studies. The STROBE quality of reporting scores of the studies ranged from 12 to 18. Seven papers described expectations of the treatment experiences, along with seven talking about benefit expectations from the treatment. Dental appearance and function improvement were most expected in studies relate to the treatment benefits.ConclusionsOrthodontics appears to have adopted various standardized questionnaires. However, most of them are poor in the quality of methodology and results analyses, which prohibit synthesizing sufficient evidence to help identify which factors influence patient expectations. The evidence of “expectations” affecting treatment outcomes is not found in current research. Future studies are needed to better understand the impact of “expectation” on the treatment both theoretically and experimentally.

Association of breastfeeding and three-dimensional dental arch relationships in primary dentition

BackgroundThe benefits of breastfeeding on oral health are still inconclusive, especially the association on occlusion. This study aimed to investigate the association of breastfeeding and the development of primary dentition.MethodsA cross-sectional study was conducted with 851 Asian children aged 2–5 years old in Hong Kong. Questionnaires were completed by the parents to collect information on breastfeeding and the non-nutritive sucking habits. The children’s dental arch relationships were examined in the sagittal, vertical, and transverse dimensions by an experienced examiner.ResultsChildren who experienced pure breastfeeding for more than 6xa0months had a lower chance of developing a class II incisal relationship (Pu2009<u20090.05) or an increased overjet (Pu2009<u20090.05), and had wider intercanine (Pu2009<u20090.05) and intermolar widths (Pu2009<u20090.05). Vertically, no association on the extent of overbite or openbite was found (P >0.05).ConclusionsPure breastfeeding for more than 6xa0months is positively associated with primary dental arch development in the anterior sagittal dental segment and on the horizontal arch width in primary dentition. Therefore, pure breastfeeding for more than 6xa0months is recommended, as it is associated with lower chance of the development of abnormal dental relationships. The results will be valuable for education and promotion of maternal breastfeeding.

A protocol for improved stability with Herbst Appliance Treatment for adults

OBJECTIVEnTo present a treatment protocol for improved stability with Herbst appliance treatment in Class II adult cases.nnnMATERIALS AND METHODSnSixteen Class II adults were treated at the University of Hong Kong with two phase treatment. The treatment protocol which leads to good stability was presented.nnnRESULTSnThe protocol leading to stable correction of overjet, molar relationship and enhanced forward positioning of the mandible involved 12 months Herbst appliance treatment with stepwise advancement followed by fixed appliance.nnnCONCLUSIONSnThe long term stability of Herbst appliance treatment is influenced by the treatment protocol employed. Based on the stability of the adult group in the present study, it is recommended to treat for 12 months in a step-wise manner for mandibular advancement with over correction.