Mechanical force increases tooth movement and promotes remodeling of alveolar bone defects augmented with bovine bone mineral.

BACKGROUND: Orthodontic tooth movement (OTM) in a region containing alveolar bone defects with insufficient height and width is hard to achieve. Bovine bone mineral (Bio-Oss) is available to restore the alveolar defect; however, whether the region augmented with a bovine bone mineral graft (BG) is feasible for OTM, and the mechanisms by which macrophages remodel the BG material, is uncertain under the mechanical force induced by OTM. MATERIAL AND METHODS: Rats were divided into three groups: OTM (O), OTM + BG material (O + B), and Control (C). First molars were extracted to create bone defects in the O and O + B groups with bovine bone mineral grafting in the latter. Second molars received OTM towards the bone defects in both groups. After 28 days, maxillae were analyzed using microfocus-computed tomography (µCT) and scanning-electron-microscopy (SEM); and macrophages (M1/M2) were stained using immunofluorescence. THP-1 cell-induced macrophages were cultured under mechanical force (F), BG material (B), or both (F + B). Phagocytosis-related signaling molecules (cAMP/PKA/RAC1) were analyzed, and conditioned media was analyzed for MMP-9 and cytokines (IL-1ß, IL-4). RESULTS: Our study demonstrated that alveolar defects grafted with BG materials are feasible for OTM, with significantly increased OTM distance, bone volume, and trabecular thickness in this region. SEM observation revealed that the grafts served as a scaffold for cells to migrate and remodel the BG materials in the defect during OTM. Moreover, the population of M2 macrophages increased markedly both in vivo and in cell culture, with enhanced phagocytosis via the cAMP/PKA/RAC1 pathway in response to mechanical force in combination with BG particles. By contrast, M1 macrophage populations were decreased under the same circumstances. In addition, M2 macrophage polarization was also indicated by elevated IL-4 levels, reduced IL-1ß levels, and less active MMP-9 in cell culture. CONCLUSION: This study explored the mechanisms of mechanical force-induced alveolar bone remodeling with bovine bone mineral grafts during OTM. The results might provide molecular insights into the related clinical problems of whether we can move teeth into the grafted materials; and how these materials become biologically remodeled and degraded under mechanical force.

[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.

Reliability assessment and correlation analysis of evaluating orthodontic treatment outcome in Chinese patients.

This study aimed to assess the reliability of experienced Chinese orthodontists in evaluating treatment outcome and to determine the correlations between three diagnostic information sources. Sixty-nine experienced Chinese orthodontic specialists each evaluated the outcome of orthodontic treatment of 108 Chinese patients. Three different information sources: study casts (SC), lateral cephalometric X-ray images (LX) and facial photographs (PH) were generated at the end of treatment for 108 patients selected randomly from six orthodontic treatment centers throughout China. Six different assessments of treatment outcome were made by each orthodontist using data from the three information sources separately and in combination. Each assessment included both ranking and grading for each patient. The rankings of each of the 69 judges for the 108 patients were correlated with the rankings of each of the other judges yielding 13 873 Spearman rs values, ranging from -0.08 to +0.85. Of these, 90% were greater than 0.4, showing moderate-to-high consistency among the 69 orthodontists. In the combined evaluations, study casts were the most significant predictive component (R(2)=0.86, P<0.000 1), while the inclusion of lateral cephalometric films and facial photographs also contributed to a more comprehensive assessment (R(2)=0.96, P<0.000 1). Grading scores for SC+LX and SC+PH were highly significantly correlated with those for SC+LX+PH (r(SC+LX)vs.(SC+LX+PH)=0.96, r(SC+PH)vs.(SC+LX+PH)=0.97), showing that either SC+LX or SC+PH is an excellent substitute for all three combined assessment.

Validation of the American Board of Orthodontics Objective Grading System for assessing the treatment outcomes of Chinese patients.

INTRODUCTION: Orthodontics in China has developed rapidly, but there is no standard index of treatment outcomes. We assessed the validity of the American Board of Orthodontics Objective Grading System (ABO-OGS) for the classification of treatment outcomes in Chinese patients. METHODS: We randomly selected 108 patients who completed treatment between July 2005 and September 2008 in 6 orthodontic treatment centers across China. Sixty-nine experienced Chinese orthodontists made subjective assessments of the end-of-treatment casts for each patient. Three examiners then used the ABO-OGS to measure the casts. Pearson correlation analysis and receiver operating characteristic curve analysis were conducted to evaluate the correspondence between the ABO-OGS cast measurements and the orthodontists' subjective assessments. RESULTS: The average subjective grading scores were highly correlated with the ABO-OGS scores (r = 0.7042). Four of the 7 study cast components of the ABO-OGS score-occlusal relationship, overjet, interproximal contact, and alignment-were statistically significantly correlated with the judges' subjective assessments. Together, these 4 accounted for 58% of the variability in the average subjective grading scores. The ABO-OGS cutoff score for cases that the judges deemed satisfactory was 16 points; the corresponding cutoff score for cases that the judges considered acceptable was 21 points. CONCLUSIONS: The ABO-OGS is a valid index for the assessment of treatment outcomes in Chinese patients. By comparing the objective scores on this modification of the ABO-OGS with the mean subjective assessment of a panel of highly qualified Chinese orthodontists, a cutoff point for satisfactory treatment outcome was defined as 16 points or fewer, with scores of 16 to 21 points denoting less than satisfactory but still acceptable treatment. Cases that scored greater than 21 points were considered unacceptable.

[Research on Chinese orthodontic specialists' subjective evaluation of orthodontic treatment outcome].

OBJECTIVE: To analyze the results of multiple Chinese orthodontic specialists' subjective evaluation of orthodontic treatment outcome, to investigate the relevance of different experiment items and to explore the weight of each monomial material. METHODS: As a randomized clinical trial, with six orthodontic treatment centers and Angle's classification being regarded as two stratification factors, it contained 108 cases with integrity data, which was random extracted from 2383 cases that received orthodontic treatment in six orthodontic treatment centers during the past five years, gathering post-treatment study casts, cephalometrics and photographs of 48 cases as the research subject. Similarly taking Angle's classification as a stratification factor, 108 cases were randomly divided into 9 groups. The randomization of sampling and grouping were both generated by a pseudo-random number generator. According to the monomial and combined subjects, 69 orthodontic specialists were regarded as the raters to rank the 12 cases in each group, and to judge whether the case was qualified. RESULTS: Correlation analysis: the Spearman r between Post-M + C and Post-M + C + P and the Spearman r between Post-M + P and Post-M + C + P were both greater than 0.950. The Spearman r between Post-M and Post-P and the Spearman r between Post-M and Post-C were about 0.300. The Spearman r between Post-P and Post-C was 0.505. Regression analysis: the linear regression results: M + C = 0.782M + 0.308C - 0.150, M + P = 0.804M + 0.233P - 0.091, M + C + P = 0.764M + 0.243P + 0.131C - 0.291. The r(2) of above three models was greater than 0.9. CONCLUSIONS: It was applicable to use M + C and M + P instead of M + C + P. Study casts could not replace cephalometrics or photographs when doing subjective evaluation. Cephalometrics and photographs could not substitute for each other either. In the combined materials evaluation, model accounted for the largest percentage. Based on the regression model, for the greater part, the integration of several monomial materials could replace the combined material assessment effectively.

[Agreement analysis of subjective evaluation of orthodontic treatment outcome].

OBJECTIVE: To investigate the agreement of subjective evaluation of orthodontic treatment outcome and to analyze possible factors that may be related to it. METHODS: As a randomized clinical trial, with Angle's classification as a stratification factor, our study contained 48 cases with integrity data, which were randomly extracted from 806 orthodontic treatment cases in Peking University School and Hospital of Stomatology during July 2004 and August 2008, and gathered post-treatment study casts, cephalometrics and photographs of the 48 cases as the research subjects. Similarly with Angle's classification as a stratification factor, the 48 cases were randomly divided into 4 groups. According to the monomial and combined subjects, 12 clinicians were asked to act as the raters to rank the 12 cases in each group. RESULTS: Overall, there were 1 584 pairings between the raters in the examination of evaluation. The mean Spearman r was 0.565 3 ± 0.239 9. Grouping factor was related to the agreement of subjective evaluation (P<0.05). In the third trial item-Post-M+P, the correlations were the greatest among the judge-pairs (P<0.001). The other five items were at the same agreement level. The level of orthodontic treatment outcome was a factor that influenced the agreement level of subjective evaluation (P<0.05). The score stability of the patients, whose treatment duration was longer than 2.5 years, was significantly higher than that of the patients whose treatment duration was between 1.5 years and 2.5 years (P<0.05). The following factors, such as Angle's classification, age of patients and whether the teeth was extracted or not, were the insignificant factors (P>0.05). CONCLUSION: The average correlations present a moderate agreement level. Grouping, experimental item, the length of treatment duration and the level of orthodontic treatment outcome are the factors that affect the agreement of subjective evaluation. Several factors including Angle's classification, age of patients and whether the teeth is extracted or not, do not affect the agreement of subjective evaluation.

[Application and comparison of two shade guide training systems].

OBJECTIVES: To evaluate the effect of shade guide training box and shade guide training software on shade matching ability of observers when used separately. To find out the difference between two training plans when the two training methods were used in combination, and to provide information on shade matching training system. METHODS: Sixty-two postgraduate dental students who specialized in prosthodontics with 1 to 5 year clinical experience were enrolled in this study. At base line, each participant were asked to match 7 standard shade tabs which have been randomly chosen from Vita 3D-Master shade guide and 7 intermediate shade tabs from Vita bleached guide 3D-Master. Then the subjects were allocated to 2 groups [Toothguide Training Box (TTB) group and Toothguide Training (TT) group] according to the baseline data. Participants in group TTB received training session once a week for 3 weeks, while those in group TT received TT training session once a week for 3 weeks. All participants took a middle term shade-matching test. Then the two groups exchange the training methods and repeat the whole process, a final test was given to each participant. The elapsed time and number of accurate shade matching were recorded for each training session. Wilcoxon signed ranks test and ANOVA were used in data analysis. RESULTS: There were no significant differences in the number of accurate shade matching (standard shade tab and the sum) between group TTB (4.4 +/- 1.3 and 5.3 +/- 1.6) and TT (4.0 +/- 1.4 and 4.9 +/- 1.5) in the middle term test with higher value found in group TTB. In the final test, the number of accurate shade matching (standard shade tab and the sum) in group TT (4.9 +/- 0.8 and 6.4 +/- 0.8) was higher than that in group TTB (4.7 +/- 1.1 and 5.8 +/- 0.9), but significant difference was found only when the sum number of accurate shade matching was compared between the two groups (P < 0.05). There was no significant difference between data from middle term test and from final test in group TTB; while in group TT, the number of accurate shade matching in the final test was significantly increased compared with that in the middle term test (P < 0.05). CONCLUSIONS: When used in combination, TT training followed by TTB training is recommended.