China experts' consensus on preventive and interceptive orthodontic treatments of malocclusions of children.

Malocclusion is one of the three most common oral diseases reported by World Health Organization(WHO). In China, its incidence rate is rising. Malocclusion seriously affects the dental and maxillofacial function, facial appearance and growth development of nearly 260 million children in China, and what is more, it affects their physical and mental health development. Malocclusion occurrence is related to genetic and environmental factors. Early treatment of malocclusion can create a good dental and maxillofacial development environment, correct abnormal growth and control the adverse effects of abnormal genetic factors. It can effectively reduce the prevalence of children's malocclusion and enhance their physical and mental health. This is an urgent need from the economic perspective of our society, so it has great practical and social significance. Experts from the project group "standard diagnose and treatment protocols for early orthodontic intervention of malocclusions of children" which initiated by China National Health Institute of Hospital Administration wrote the "China Experts' Consensus on Preventive and Interceptive Orthodontic Treatments of Malocclusions of Children", which aims to guide and popularize the clinical practice, improve the clinical theory and practice level, and accelerate the disciplinary development of early treatment of children's malocclusion in China. The consensus elaborates the harmfulness of malocclusion and the necessity of early treatment, and brings up the principles and fundamental contents. Based on the law of dental and maxillofacial development, this paper puts forward the guiding suggestions of preventive and interceptive treatments in different stages of dental development ranging from fetus to early permanent dentition. It is a systematic project to promote and standardize the early treatment of malocclusion. Through scientific and comprehensive stratified clinical practice and professional training, the clinical system of early treatment of malocclusion in China will eventually be perfected, so as to comprehensively care for children's dental and maxillofacial health, and improve their oral and physical health in China.

Analysis of correlation of 3-dimensional lip vermilion morphology and dentoskeletal forms in young Chinese adults on the basis of sex and skeletal patterns.

INTRODUCTION: The objective of this research was to evaluate the correlation between 3-dimensional (3D) lip vermilion (LV) morphology and skeletal patterns as well as incisor measurements in young Chinese adults. METHODS: In all, 240 young adults were enrolled; these included 80 patients each with skeletal Class I, Class II, and Class III malocclusions, respectively. Each sagittal skeletal pattern included 40 male and 40 female subjects. Twenty-two 3D LV measurements were obtained from 3D facial scans. Skeletal and incisor measurements were evaluated on lateral cephalograms. Correlation and regression analysis were performed between soft and hard tissue measurements. RESULTS: Six of 22 LV measurements showed significant differences between male and female subjects. The 3D LV morphology showed significant differences with respect to different skeletal patterns and sex. Adults with skeletal Class III malocclusion tended to have thinner upper vermilion and fuller lower vermilion than subjects with skeletal Class II and III malocclusion. The mandibular plane angle negatively correlated with the upper-lower vermilion midsagittal curve length and surface area ratio in adults with skeletal Class I and II malocclusion, yet the vertical facial skeletal type showed no correlation in adults with skeletal Class III malocclusion. The vermilion angle, central bow angle, vermilion height, vermilion midsagittal curve length, vermilion height and width ratio, and vermilion surface area showed a significant correlation with incisor measurements. Regression analysis found that the ANB angle was an important factor affecting the upper and lower vermilion midsagittal curve length and surface area ratio. Further, the vermilion height and height and width ratio were closely correlated with the interincisal (U1/L1) angle, whereas the central bow angle was closely correlated with the maxillary incisor torque. CONCLUSIONS: Most LV morphology variables were correlated to skeletal patterns and incisor measurements. Skeletal Class III malocclusion showed significant differences in vermilion morphology. Both the sagittal and vertical skeletal pattern have effects on vermilion proportion. The incisor torque was closely correlated to vermilion shape and central bow angle and might influence the vermilion esthetics. However, the proportion of the upper and lower vermilion was mainly affected by the ANB angle.

Measurement of three-dimensional changes in lip vermilion in adult female patients after orthodontic extraction: a retrospective longitudinal study.

BACKGROUND: 3D facial scanning has changed the way facial aesthetic is evaluated and has numerous advantages for facial analysis. The specific relationship between lip vermilion morphological changes after orthodontic extraction treatment has not been fully explained. The objective of this study was to evaluate 3D morphological changes after orthodontic extraction treatment in lip vermilion of adult females with dentoalveolar protrusion using a structured light-based scanner. METHODS: Forty-two female subjects (25.2 ± 1.9 years) were recruited as the treatment group; these patients had undergone extraction treatment and achieved better sagittal profiles. Twenty female subjects (25.5 ± 2.1 years) were enrolled in the non-treatment group; these patients did not require any orthodontic treatment. The follow up time for the treatment group was more than 24 months and for the non-treatment group was more than 12 months. 3D facial scans were captured using 3D CaMega. Six landmarks (Ls, Li, R.Chp, L.Chp, R.Ch, and L.Ch), three linear measurements (mouth height, philtrum width, and mouth width), and three area measurements (upper, lower, and total vermilion area) were measured. The spatial deviations of three volumetric measurements (upper, lower, and total vermilion) were constructed for quantitative analysis. Color-coded displacement map were constructed for visualization of the soft-tissue displacement as qualitative evaluation. RESULTS: Mouth height and philtrum width decreased (-0.93 mm and - 1.08 mm, respectively) significantly (p = 0.008 and p = 0.027, respectively), and no significant (p = 0.488) change in mouth width was observed in the treatment group. The lower and total vermilion surface areas decreased (-51.00mm2 and - 69.82mm2, respectively) significantly (p = 0.003 and p = 0.031, respectively) in the treatment group, but no statistically significant (p = 0.752) change was detected in the upper vermilion. In the treatment group, significant retractions were observed in the color-coded displacement map, and three volumetric measurements of vermilion changed significantly (p = 0.012, p = 0.001 and p = 0.004, respectively). Significant differences were found between the treatment group and the non-treatment group in the linear, area and volumetric measurements. CONCLUSIONS: This study established a method for qualitative and quantitative evaluation of the lip vermilion. Significant 3D retraction of the lip vermilion after the extraction treatment was found, with morphological variation between upper and lower vermilion.

Three-dimensional analysis of the physiologic drift of adjacent teeth following maxillary first premolar extractions.

We assessed the three-dimensional (3D) pattern of the physiologic drift of the remaining adjacent teeth after premolar extraction due to orthodontic reasons and the associated factors. Data were collected from 45 patients aged 17.04 ± 5.14 years who were scheduled to receive a fixed appliance after maxillary premolar extraction. Seventy-five drift models were obtained and digitalized via 3D scanning. The average physiologic drift duration was 81.66 ± 70.03 days. Angular and linear changes in the first molars, second premolars, and canines were measured using the 3D method. All the examined teeth had tipped and moved towards the extraction space, leading to space decreases. Posterior teeth primarily exhibited significant mesial tipping and displacement, without rotation or vertical changes. All canine variables changed, including distal inward rotation and extrusion. The physiologic drift tended to slow over time. Age had a limited negative effect on the mesial drift of posterior teeth, whereas crowding had a limited positive effect on canine drift. Thus, the mesial drift of molars after premolar extraction may lead to molar anchorage loss, particularly among younger patients. The pattern of the physiologic drift of maxillary canines can help relieve crowding and facilitate labially ectopic canine alignment, whereas canine drift is accelerated by more severe crowding.

Three-dimensional changes in lip vermilion morphology of adult female patients after extraction and non-extraction orthodontic treatment.

OBJECTIVE: To investigate the three-dimensional lip vermilion changes after extraction and non-extraction orthodontic treatment in female adult patients and explore the correlation between lip vermilion changes and incisor changes. METHODS: Forty-seven young female adult patients were enrolled in this study (skeletal Class III patients were excluded), including 34 lip-protruding patients treated by extraction of four first premolars (18 patients requiring mini-implants for maximum anchorage control and 16 patients without mini-implants) and 13 patients requiring non-extraction treatment. Nine angles, seven distances, and the surface area of the lip vermilion were measured by using pre- and post-treatment three-dimensional facial scans. Linear and angular measurements of incisors were performed on lateral cephalograms. RESULTS: There were no significant changes in the vermilion measurements in the non-extraction group. The vermilion angle, vermilion height, central bow angle, height/width ratio, and vermilion surface area decreased significantly after the orthodontic treatment in the extraction groups, but the upper/lower vermilion proportion remained unchanged. Significant correlations were found between the changes in incisor position and those in vermilion angles, vermilion height, and surface area. CONCLUSIONS: Extraction of the four first premolars probably produced an aesthetic improvement in lip vermilion morphology. However, the upper/lower vermilion proportion remained unchanged. The variations in the vermilion were closely related to incisor changes, especially the upper incisor inclination changes.

Correlation Between Cephalometric Measures and End-of-Treatment Facial Attractiveness.

Sixty-nine experienced Chinese orthodontists evaluated 108 Chinese patients' facial attractiveness from set of photographs (frontal, lateral, and frontal smiling photos) taken at the end of orthodontic treatment. These 108 patients, which contained an equal number of patients with Class I, II, and III malocclusion, were randomly selected from 6 orthodontic treatment centers throughout China. Spearman rank-order correlation coefficients (rs) analyses were performed to examine agreement in ranking between all judge pairs. Pearson correlation and multivariate regression were performed to examine the correlation between cephalometric measures and end-of-treatment Photo Attractiveness Rank.96.68% judge pairs showed moderate correlated (+0.4 ≤ rs < +0.7) subjective rankings. Cephalometric measures significantly correlated with end-of-treatment Photo Attractiveness Rank included interincisal angle (r = 0.330, P < 0.05), L1/MP° (r = 0.386, P < 0.05), L1-NBmm (r = 0.451, P < 0.01), L1/NB° (r = 0.374, P < 0.05), and profile angle (r = 0.353, P < 0.05) in Class I patients with an explained variance of 32.8%, and ANB angle (r = 0.432, P < 0.01), angle of convexity (r = 0.448, P < 0.01), profile angle (r = 0.488, P < 0.01), Li to E-line (r = 0.374, P < 0.05), Li to B-line (r = 0.543, P < 0.01), and Z angle (r = 0.543, P < 0.01) in Class II patient with an explained variance of 43.3%.There was less association than expected between objective measurements on the lateral cephalograms and clinicians' rankings of facial attractiveness on clinical photography in Chinese patients. Straight-stand lower incisor was desired for facial attractiveness of Class I malocclusion; and sagittal relationship and lip prominence influence the esthetics of Class II malocclusion in Chinese population.

[Validation of subjective and objective evaluation methods for orthodontic treatment outcome].

OBJECTIVE: To assess the correlations between objective measurements of 108 finished orthodontic cases and subjective assessments made by 69 orthodontic specialists, to explore the statistically significant measuring categories of cast and cephalogram and to validate the regression model. METHODS: A stratified random sample of 108 cases was drawn from the large sample of 2 383 patients who finished orthodontic treatment between July 2006 and August 2008 in six orthodontic treatment centers around China. For each patient, the post-treatment information sources evaluated in this study included standardized plaster study casts and a lateral cephalometric X-ray image. These information sources were evaluated both singly and in combination by a panel of 69 orthodontic specialists. The average subjective grading scores of 69 orthodontists were regarded as the gold standard. Six examiners used the peer assessment rating (PAR) index and American board of orthodontics-objective grading system (ABO-OGS) to measure all the study casts respectively and three other examiners measured all the lateral cephalometric X-ray images by using customized software. The objective measuring data were correlated with the gold standard. The correlations between the objective measurement and the subjective evaluation were assessed, the statistically significant measuring categories of cast and cephalogram were explored and the regression model was validated. RESULTS: The ABO-OGS scores of "occlusal relationship" correlated most strongly with the subjective scores of cast (r=0.655, P<0.01), and the secondarily correlated category with those were the PAR scores of "overjet" (r=0.525, P<0.01). The proclination of the lower incisors correlated most strongly with the subjective scores of cephalogram (r=0.446, P<0.01), and the secondarily correlated category with those was the protrusion of the lower lips (r=0.436, P<0.01). Nine components were predictive for the post-treatment model and lateral ephalometric film (Post-M+C) outcome: alignment (ABO-OGS), occlusal relationship (ABO-OGS), interproximal contact(ABO-OGS), L1/NB°, overjet (PAR), SNB°, occlusal contacts (ABO-OGS), U1/SN2° and centerline (PAR). These 9 components accounted for 72% of the variability in the average subjective grading scores. CONCLUSION: The objective regression model could replace the averaged opinion of Chinese orthodontic experts effectively, making objective assessment of orthodontic treatment outcome for Chinese patients.

Root resorption before and after orthodontic treatment: a clinical study of contributory factors.

This clinical study evaluated factors related to root resorption before (T1) and after (T2) orthodontic treatment. Ninety-six subjects between 9 and 34 years (34 males and 62 females) who had been treated using fixed appliances for at least 1 year and who had panoramic radiographs at T1 and T2 were selected. The relationship between root resorption at T1 and T2, with regard to gender, age, extraction versus non-extraction patterns, specific teeth and treatment duration was investigated. No statistically significant differences in root resorption were found in relation to gender. Significant differences in root resorption (P = 0.000, P < 0.01) and also in treatment duration (P = 0.036, P < 0.05) were noted between the extraction and non-extraction groups; extraction and treatment duration correlated with T2 mean root resorption. Patient age correlated with root resorption of the upper incisors at T1 and T2. Using multiple regression analysis, age and duration of treatment were found to be more associated with root resorption than with extractions; the presence of root resorption at T1 was associated with T2 root resorption, especially of the anterior teeth.

[Non-extraction treatment with self-ligating and conventional brackets].

OBJECTIVE: To compare the dental change and the mechanism after non-extraction treatment between passive self-ligating and conventional bracket systems. METHODS: Twenty-six non-extraction crowding cases were selected. Half of them were treated with Damon3 self-ligating brackets and the others were treated with conventional brackets. The results were compared. Stepwise regression analysis was performed for the two groups. RESULTS: There were no statistically significant differences in the changes of the intercanine and interpremolar widths and L1-MP angle (P > 0.1). In the self-ligating bracket group, the intermolar width increased by 1.42 mm and the L1-APo increased by 2.66 mm. In the conventional appliance group, the intermolar width increased by 0.65 mm and L1-APo increased by 1.57 mm. The differences were statistically significant between the two groups (P < 0.1). Stepwise regression analysis showed that in self-ligating bracket group, the coefficient of determination for the changes of L1-MP was 96.6%. CONCLUSIONS: In crowding cases treated with non-extraction, there were an overall increase in the proclination of the mandibular incisors and the arch width in both bracket groups. Compared with cases treated with conventional appliances, the cases treated with Damon3 brackets resulted in greater intermolar width increases; In Damon3 bracket group, the change of the lower incisor inclination was influenced not only by the mandibular crowding and the intermolar width before treatment but also by the patient's skeletal pattern and the changes of the arch width during treatment.

Reconstruction of a huge oral maxillofacial defect caused by necrotic fasciitis secondary to leukaemia.

SUMMARY: An 8-year-old boy who was diagnosed with 'acute non-lymphoblastic leukaemia (M2)', contracted secondary oral maxillofacial necrotic fasciitis. The wound was cleaned with 3% hypertonic saline, and then covered with iodoform gauze every day for about 3 weeks before and after necrotic tissue debridement. The local infection was controlled, and plenty of new healthy granular tissue had grown. The patient was left with a huge defect including the mouth floor, submental area, submandibular area and right cheek when the necrotic tissue was removed. Reconstruction of the defect was very difficult because of the patient's pre-existing leukaemia condition and severe inflammatory local condition. We successfully reconstructed the defect by using the new healthy granular tissue and a trapezius myocutaneous flap. During 9 years of follow up, in order to improve quality of life, the patient underwent scar modification surgery and orthodontic treatment, and facial appearance and oral functions were deemed satisfactory.

[Gnathosonics study of the occlusal stability of orthodontic patients].

OBJECTIVE: To analysis the stability of the occlusion before and after the orthodontic treatment by gnathosonics; To evaluate the reliability of the stethoscope method by comparing the subjective(stethoscopy) and objective(digital occlusal sound recording) methods of checking the occlusal sound. METHODS: Sixty-four new patients with malocclusion were selected as the before treatment group, these patients were not subject to any previous orthodontic treatment, facial surgery or injury; the treatment complete group included 15 patients who were just debonded the fixed appliance. Both stethoscope and digital occlusal sound recording were used to evaluate the occlusal sound. The occlusal stability before and after orthodontic treatment was compared depending on the results from the objective examination. The stability of the occlusion between different types of malocclusion before treatment was compared also. The veracity and reliability of the stethoscope method were analysis using the objective method as the golden standard. RESULTS: (1) 43.75%(28/64) of the 64 new patients showed unstable occlusal sound. ANOVA test showed that there were no statistically significant differences between the unstable rates in different type of malocclusion. (2) 40% (6/15) of the 15 treatment complete patients had unstable occlusions. (3) There were no statistically significant differences between the unstable rate pre- and post-treatment. (4) The veracity of the stethoscopes was 81.01% (64/79). (5) Kappa test showed that the stethoscopes and the digital recording method were consistent; the Kappa value was 0.488, P<0.001. CONCLUSION: (1) There was no statistically significant difference of the unstable occlusion rate between the two groups, and between the different types of malocclusion before treatment. (2) Using stethoscopes method to check the occlusal sound is reliable. The veracity could be improved significantly with increased experiences.

[A factors study of root resorption after orthodontic treatment].

OBJECTIVE: To investigate the factors relating to root resorption after orthodontic treatment. METHODS: 96 cases treated with fixed appliances were selected. The panoramic radiographs before and after treatment were examined. The relationship between root resorption after treatment (RRAT) and the variables including sex, age, extraction or nonextraction approach, tooth location, treatment duration and the root resorption before treatment (RRBT) were analyzed by multiple variance analysis and stepwise multivariate linear regression analyses. RESULTS: (1) There were statistically significant differences in root resorption in relation to gender (estimate of RRAT for female: 0.41, that for male: 0.34), extraction (estimate of RRAT for the extraction group: 0.43, that for non-extraction: 0.31), anterior or posterior teeth (estimate of RRAT for the anterior teeth: 0.59, that for the posterior teeth: 0.12). (2) The estimate of RRAT for the upper teeth was 0.40, and that for the lower teeth was 0.37. There were no statistically significant differences. (3) Using multiple regression analysis, age, duration and RRBT were associated with RRAT (R = 0.59, R(2) = 0.35). CONCLUSIONS: (1) Factors including gender, extraction or not and anterior or posterior teeth have influences on the RRAT. More root resorption was found in female or extraction cases. Anterior teeth were more susceptible to root resorption relative to posterior teeth. (2) Age, treatment duration and RRBT can explain approximately 35% of the RRAT. Root resorption aggregated when it was present before treatment. The age and treatment duration were lightly related to the root resorption.