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Objective@#To explore the effect of RW splints on the position and occlusal relationship of classⅡ malocclusion patients with temporomandibular disorder (TMD) to provide a basis for the diagnosis and design of this kind of patient. @*Methods @#Fifteen patients with class Ⅱ malocclusions with TMD were enrolled in this study. After 8 months of RW-splint treatment, the changes in jaw position (∠ANB, SN-MP, ∠S-G0/N-Me) and occlusal relationship (molar, cuspid teeth displacement and anterior overbite/overjet value) were recorded by a condylar displacement measuring instrument at the CR position and CO position.@*Results@#After RW-splint treatment, the mean values of ∠ANB (t=4.971, P=0.001) and ∠SN-MP (t=9.895, P ＜ 0.01) were increased in all 15 patients, and the mean value of S-G0/N-Me (t=5.342, P=0.005) was decreased. The mean values of the distal movement of the first molars on the left and right sides of the mandible were (1.57 ± 0.79) mm and (1.69 ± 1.29) mm, respectively; the mean values of the distal movement of the canines on the left and right sides of the mandible were (1.54 ± 0.50) mm and (1.51 ± 1.08) mm, respectively; and the mean values of the overbite were (1.16 ± 0.60) mm and (1.99 ± 0.85) mm, respectively. @*Conclusion@# After RW-splint treatment, the jaw rotates clockwise, and the relationship between the molars and canines changes obviously in class Ⅱ patients with TMD, which provides a reference for the diagnosis and treatment plan of this kind of patient.
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Objective To study the clinical effect of bone-anchored pendulum in treatment for class Ⅱ malocclusion .Methods Twelve patients treated by bone-anchored pendulum were chosen .In each patient ,two microscrews were inserted in the anterior paramedian region of the median palatal suture ,6-9 mm posterior to the incisive foramen and 3 – 6 mm lateral to the median line .Pendulum that based on the microscrews was used to distalize maxillary first molar ,and the force applied was 250 g .Skeletal and dental changes were measured on cephalograms before (T1 ) and after (T2 ) distal-ization .Results Class Ⅰ molar relationship had been obtained 7 month after distalization .The aver-age distal movement of the maxillary first molars was 7 .07 mm ,and the inclination was 9 .93° .The second premolars were distalized an average of 5 .44 mm with inclinations of 5 .22° .The first premolars were distalized an average of 4 .09 mm with inclinations of 3 .95° .The maxillary anterior teeth were re-truded 0 .93 mm and palatally inclined 1 .66° .There was statistical difference in that change .Conclusions By the use of microscrew ,pendulum can distalize maxillary molar effectively without mesial move-ment of premolar and labial movement of incisor ,and no loss of dental anchorage is observed during the distal movement .
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Objective • Using cone-beam computed tomography (CBCT) to compare alveolar bone changes in maxillary anterior area secondary to maxillary incisor retraction adjunct with tip (R&Tp) and retraction adjunct with torque (R&Tq) movements. Methods • Forty teenagers with Angle's class Ⅱ division 1 malocclusion who had completed orthodontic treatment met the inclusion criteria and were selected, and all of their 160 maxillary incisors were classified into two categories, namely R&Tp group and R&Tq group, according to their actual retraction pattern. Pre- and post-treatment CBCT images and 3D measurement software were used to measure and analyze tooth retraction and alveolar bone height and thickness changes within each group and to compare treatment changes of teeth and alveolar bone between two groups. Results • Anterior teeth in each group were intensively retracted and uprighted, with a longer retraction distance of incisal edge and a greater retraction angle of teeth in R&Tp group than in R&Tq group (both P=0.000). Alveolar bone thickness was significantly decreased at L3 and P1 in R&Tp group (both P<0.05), while it was significantly decreased at P1 and P2 in R&Tq group (both P<0.05). Total alveolar bone thickness decreased at T1 in R&Tp group (P=0.000) and at all levels in R&Tq group (all P=0.000). Finally, alveolar ridge height in two groups dropped both in the buccal (both P=0.000) and palatal (both P=0.000) sides, with a more prominent extent in the palatal side, and ridge height dropped most in palatal side of the teeth in R&Tq group. Conclusion • The buccal root apex area and the palatal alveolar ridge area of alveolar bone in the R&Tp group and the cervical and middle area of incisor root in palatal side of alveolar bone in the R&Tq group are high-risk areas for alveolar bone resorption when anterior teeth in teenagers with Angle's class Ⅱ division 1 malocclusion are intended to have en masse retraction.
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Objective@#To investigate the effect of corticotomy-facilitated orthodontics on the treatment time and final outcome in skeletal class Ⅱ division 1 patients.@*Methods@#Twenty adult skeletal class Ⅱ division 1 patients treated with two maxillary first premolar extractions were included and randomly divided into two groups (the corticotomy group and the control group). The treatment time was recorded and the changes of soft and hard tissue were compared by using three-dimensional measurement and analysis of cone-beam CT images before and after treatment.@*Results@#There was no significant difference in the alignment time between two groups, while the time of maxillary space closure and the total treatment time in corticotomy group ([5.8±1.3] and [24.9±5.1] months, respectively) were shorter than that in the control group ([9.9±1.1] and [30.8±4.6] months, respectively) and the differences were significant (P<0.01). In the corticotomy group, the retraction amount of the upper central in cisal margin, apical tip, supradentale, labrale superius and the increase of nasolabial angle were greater than those in the control group (P<0.05).@*Conclusions@#In patients with mild to moderate skeletal class Ⅱ division 1 malocclusion, corticotomy-facilitated orthodontics can not only shorten the treatment time, but is more conductive to the retraction of upper anterior teeth and improvement of the profile.
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Objective @#To compare the depth of the curve of Spee in Angle classⅡ malocclusion patients with different vertical skeletal patterns and to investigate the relationship between the depth of the curve of Spee and dentofacial morphology. @*Methods @#101 Angle classⅡ malocclusion patients were selected and randomly divided into 3 groups based on their GoGn-SN angles-high angle, average angle and low angle. Lateral cephalograms and dental models of all patients were evaluated to analyze Spee curve depth difference among different groups, Correlation analysis and a multiple linear regression analysis were performed to determine the relationship between the depth of the curve of Spee and all selected cephalometric variables.@*Results@# There was statistical difference in depth of the curve of Spee among different groups P < 0.05. The depth of the curve of Spee was least in the high angle group and greatest in the low angle group. GoGn-SN angle had statistically significant negative correlation with the depth of the curve of Spee, r = 0.428, P = 0.000, ODI, S-Go/N-Me、L7-GoGn angle had statistically significant positive correlation with the depth of the curve of Spee, r = 0.381, 0.357, 0.333, P = 0.000, 0.000, 0.001. The multiple linear regression analysis with stepwise method showed GoGn-SN angle had significant contribution to the depth of the curve of Spee. In Angle classⅡ malocclusion patients, there was statistical difference in depth of the curve of Spee among different vertical skeletal patterns@*Conclusion @#The depth of the curve of Spee is correlated with dentofacial morphology, GoGn-SN angle had significant contribution to the depth of the curve of Spee, which should be taken into consideration during orthodontic diagnosis and treatment.
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Objective@#To investgate the effect of Herbst appliance on the growth and remodeling of the temporomandibular joint (TMJ) in class Ⅱ patients with mandibular retrusion by using MRI.@*Methods@#Between December 2010 and October 2014, 12 class Ⅱ patients (11-16 years old) with mandibular retrusion were chosen. The patients were divided into two groups. The control group included 7 patients (14 joints) with normal disc condyle relationship and the anterior disc displacement (ADD) group included 5 patients (10 joints) with anterior disc displacement. The MRI images of TMJ were measured, including condylar height, joint space index and disc position ratio, before and after the treatment.@*Results@#The condylar height of the patients in the control group was significantly increased (P<0.001) after treatment, and no significant difference in joint space index (P=0.821) and disc position ratio (P=0.146) was found. The joint space index of the patients ([-14.70±8.82]% and [4.90±11.35]%) in ADD group changed significantly (P<0.001) after treatment, and no significant difference in condylar height (P=0.294) and disc position ratio (P=0.120) was found.@*Conclusions@#The normal disc condyle relationship was beneficial to the reconstruction of the condylar process, and the increase of the condylar height. The condyle moved forward in patients with anterior disc displacement after treatment.
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Mandibular hypoplasia is very common clinically. Studies have reported that temporomandibular joint internal derangement (TMJID) might manifest as mandibular retrusion, and whether there is a direct correlation between them remains controversial in academia. On the other hand, for adolescent patients with skeletal class Ⅱ malocclusion, the growth of mandible could be motivated by orthopedic force, and then the mandibular retrusion corrected. However, if TMJID is the direct cause of mandibular retrusion, orthopedic treatment will not have a significant effect on it. Base on literature review and analysis as well as our own research, this article will review the distribution of structural abnormalities of the temporomandibular joint in adolescents with mandibular hypoplasia and its association with skeletal class Ⅱ malocclusion, as well as the effect of TMJID on the treatment of skeletal class Ⅱ malocclusion in adolescents.
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<p><b>OBJECTIVE</b>This study aimed to analyze the condylar position changes produced by functional appliances in class Ⅱ malocclusion by systematic review.</p><p><b>METHODS</b>Electronic search was conducted using Chinese Biomedical Literature Database, China National Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals, Medline, Embase, Pubmed, and Cochrane Central Register of Controlled Trials. Studies on condylar position changes produced by functional appliances in class Ⅱ malocclusion were included. Risk of bias assessment and data extraction of included studies were conducted by two reviewers independently. The meta-analysis was carried out using Revman 5.1.</p><p><b>RESULTS</b>Six studies were included (five high quality and one low quality). The condylar position showed no changes after Herbst treatment. The condylar posterior space after Twin-block treatment averagely increased by 0.31 mm (P<0.000 01), whereas the condylar anterior space averagely reduced by 0.32 mm (P<0.000 01).</p><p><b>CONCLUSIONS</b>Twin-block appliance enables forward movement of the condylar position. This result contributes to the correction of class Ⅱ malocclusion.</p>
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Humans , Databases, Factual , Malocclusion, Angle Class IIABSTRACT
Objective:To study crown-root morphology of maxillary anterior teeth in ClassⅡ,division 2 malocclusion using cone-beam CT (CBCT)combined with computer aided measurement technology to provide guidance for clinical treatment.Methods:The samples which consisted of 36 cases radiographed with CBCT techniques were selected and divided into two groups (1 8 each )based on the type of maloc-clusion presented:ClassⅡ,division 2 group (groupⅡ2)and ClassⅠgroup (groupⅠ).The measure-ments of crown-root morphology including crown-root angle and surface-shaft angle were got by Multiple Planer Reconstruction of CBCT data uploaded into InvivoDental software 5.0.The data were processed with SPSS 20.0 software package and t test was employed for comparison of angular measurements. Results:In group Ⅰ,crown-root angles of maxillary central incisor,maxillary lateral incisor and maxillary canines were 1 79.08°±3.31 °,1 76.55°±2.77°and 1 84.20°±2.51 °respectively, surface-shaft angles were 21 .00°±2.63°,1 9.63°±2.35°and 1 9.36°±2.30°respectively. While in group Ⅱ 2 ,crown-root angles of maxillary central incisor,maxillary lateral incisor and maxillary canines were 1 76.80°±2.62°,1 74.1 3°±3.28°and 1 81 .79°±2.88°respectively, surface-shaft angles were 23.20°±2.95°,22.29°±2.1 9°and 20.61 °±2.34°respectively. Compared with group Ⅰ,significant statistical differences were observed with the exception of sur-face-shaft angle of maxillary incisor.There was significant difference in crown-root angle between group Ⅱ2 and 1 80 °.Conclusion:The maxillary anterior teeth in ClassⅡ,division 2 malocclusion exhibited significant crown-root morphology which would influence the torque after orthodontic treat-ment.Special attention should be paid to the position of maxillary anterior teeth roots during ortho-dontic treatment for Class Ⅱ,division 2 malocclusion.The ideal position of tooth movement should be decided by the root rather than the location of the crowns.
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Objective To investigate changes in craniomaxillofacial soft and hard tissues following orthodontic treatment by MBT edgewise technique with fix appliance in patients with Angle classⅡdivisionⅠmalocclusion. Methods Fifty patients with Angle classⅡdivisionⅠmalocclusion were selected in this study. All patients were treated with MBT edgewise technique. Cephalometrics tracings were performed before treatment and after treatment. Cephalometrics measurements were statistically analysed by t-test. Results After the orthodontic treatment, the main changes were the reduction of maxillary and mandibular prominence and the increasement of the Pg′B′-FH and Pog-Pog′and upper-lower prominence as well. The appearance of uncovered teeth by their lips was obviously improved. The changes of soft issue profile are the increment of nasolabial angle and the changes among UL-U1, LL-L1 and the E-line. Conclusion Patients with Angle classⅡdivisionⅠmalocclusion have normal overjet and overbite, and also have a better appearance of soft tissue after the extraction treatment.
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The effect of extraction and nonextraction treatment on the soft tissue profile of the subjects borderline Angle classⅡ division 1 malocclusion is concerned mainly by orthodontists.This article reviewes the effect of extraction and nonextraction treatment on the soft tissue profile of the subjects with Angle classⅡ division 1 borderline patients and the important factors(such as differences between the types of tooth extraction and growth).The aim is to guide clinic diagnosis and treatment for borderline Angle classⅡ division 1 malocclusion.
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Objective To analyze and compare the difference of the joint position between the Angle classⅡ division 2 malocclu-sion and individual normal occlusion by dental cone beam computed tomography (CBCT).Methods 23 patients with Angle classⅡdivision 2 malocclusion according with the experimental design were selected as the experimental group and 27 cases of individual normal occlusion as the control group.Each research subj ect was performed CBCT.The images in the oblique position perpendicular to the long axis of condyloid process were reconstructed by the Examvision software.Then the joint space was measured by the Au-toCAD software and and the positional relation of the condyloid process in the articular fossa was assessed by Pullinger analysis methods.The results were compared.Results 65.2% of the condylloid process in Angle classⅡ division 2 malocclusion is posteri-orly shifted,in individual normal occlusion,64.8% of the condylloid process is in the middle place.Conclusion The condylar posi-tion of Angle classⅡ division 2 malocclusion were abnormal relative to individual normal occlusion joint,which should be early cor-rected for inducing the joint to the normal position and avoiding the generation of the joint symptoms.
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Objective To investigate the clinic application of micro-implant anchorage in the treatment of maxil-lary protrusion malocclusion. Methods Twenty-two patients,aged 18 to 25 years old,with maxillary protrusion were divid-ed into two groups:experimental group and control group with 11 patients in each group. All patients were treated with ex-traction. Micro-screw palatal implant was used in the cases of experimental group as orthodontic anchorage ,and traditional anchorage composed of extraoral arch used in the cases of control. The cephalometric films were measured before and after treatment. Statistical methods were utilized to analyze the morphological changes of facial profile and hard tissues in both groups. Results The values of U1-NA(mm:3.08±1.18 vs 8.15±3.05) and U1-SN(101.90°±3.50° vs 117.90°±6.05°) were sig-nificantly decreased after treatment compared with those before treatment in the experimental group ( P<0.01). The value of U1-L1(123.98°±5.78°vs 103.89°±8.95°) was significantly increased after treatment (P<0.01). In control group, the values of U1-NA (mm:5.01±1.34 vs 9.12±2.13) and U1-SN(101.90°±3.97° vs 114.87°±7.69°)were significantly decreased after treat-ment. The values of U1-L1(126.01°±3.12°vs 112.98°±5.98°) and U6-PtPNS(mm:21.45±2.43 vs 18.36±2.19)were significant-ly increased after treatment (P<0.05). The value of U1-L1(19.48°±8.90° vs 13.01°±5.90°) was significantly changed in exper-imental group than that of control group, but the value of U6-PtPNS(mm:0.90±0.29 vs 3.78±0.12)was significantly changed in control than that of experimental group (P<0.01). Conclusion The maxillary protrusion malocclusion with micro-im-plant anchorage can be used as treatment for patients with maxillary protrusion that needs strong anchorage.
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ObjectiveTo investigate the clinical effect of pendulum and straight wire technology in patients with fully erupted second molar.MethodsPatients with Angle class Ⅱ malocclusion were chosen.Control group included patients without erupted second molar.Experimental group included patients with completely erupted second molar.Pendulums were used in two groups to distalize maxillary molars.Then straight wire orthodontic treatment had been performed until treatment was over.Cephalograms of each stage were analyzed.ResultsIn the experimental group,mesiobuccal cusp of first molar was distalized for 4.62 mm,geometric center was distalized for 3.75 mm,about 81 percent of the movement of mesiobuccal cusp.In control group,mesiobuccal cusp of first molar was dis talized for 5.78 mm,geometric center was distalized for 3.20 mm,about 55 percent of the movement of mesiobuccal cusp.It turned out first molar was distalized in both groups,but more rotation took place in control group than that in the experimental group.ConclusionsPendulum can distalize maxillary first and second molars in patients with completely erupted second molar.The pendulum and straight wire technology can treat these patients successfully.
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Objective:Cluster and discriminant analysis of the morphological characters of Angle's Class Ⅱ malocclusion was performed using Procrusts standardization.The classification of craniofacial morphology with the help of morphometry and multivariate statistics was also discussed.Methods: A total of 894 class Ⅱ patients were collected from the orthodontic department,Peking University School and Hospital of Stomatology during 1997-2000.Using Procrusts standardization and cluster analysis,the samples were divided into different groups,discrimination equations were then established.Results: The samples were divided into 11 subdivisions by Procrusts superimposition and cluster analysis.Three discrimination equations were established.The accuracy rate of cross-validated grouped cases was 80.17%.Conclusion: Procrusts standardization had certain advantages in morphological classification;cluster analysis could be used in classification of Angle class Ⅱ malocclusion;For different types,the differentiate rate was not the same;the discrimination equations was the foundation for future research.
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Objective To investigate the imaging and condylar movements during mandibular opening/closing movement in AngleⅡ2 malocclusion accompanying one side of temporomandibular joint(TMJ)click before and after orthodontic treatment.Methods There were 20 AngleⅡ2 malocclusion patients with one side of TMJ click in treatment group,and 23 with the individual normal occlusion in control group.This study was performed taking the films of Sch?ller position before and after treatment,using CADIAX to record the condylar tracings during opening/closing movement and analyze the qualitative and quantitive changes.Results In AngleⅡ2 malocclusion patients,the condylar position of 58.33% patients recovered from retroposition to mesoposition.The condyle movement presented conspicuous verticality,the smoothing and symmetry were not well,and obvious improvements were observed after the treatment.All the index changed remarkably except the TCI and TCI of 5 mm.Conclusion It is suggested that orthodontic treatment can make the disc-condyle relationship return to normalization,and the condylar movement become much more coherent.
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砄bjective: To evaluate the effect on a transpalatal arch on reinforcing anchorage. Methods: 12 cases with ClassⅡ Division 1 malocclusion were selected and treated with a transpalatal arch for reinforcing anchorage. Results: ①The forward displacement of the first maxillary molar (6 Ptmo, 6 So, 6CR So and 6AP So) , the backward displacement(1 Ptmo and 1 So ) and the reduction of the axial inclination (1 NA and 1 SN) of the upper incisors were increased( P 0.05);③The forward displacement of the first maxillary molar was less than one third of the extraction space ( P
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Objective:To study the effects of treatment of Angle Ⅱ division 2 malocclusion with upper/lower arch expansion and Class Ⅱ elastics in adults. Methods:Expanding upper/lower arch and Class Ⅱ elastic were used to treat Angle Class Ⅱ division 2 malocclusion in 15 adults. Study models and cephalograms were analyzed before and after treatment. Results:Before and after treatment the maxillary variables of cephalograms showed no significant differences, the mandibular variables showed significant differences in sagittal and vertical direction. U1-NA, U1-PP, L1-NB, L1-MP, U1-L1 and L6-Ptm were significantly increased after treatment(P
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Objective: To evaluate the effect of Twin-block function al appliance in the treatment of transmissible obstructive sleep apnea syndrome (O SAS). Methods: 7 cases of OSAS, aged 8.6～13.2 years, with sk e letal Angle II malocclusion were treated with Twin-block fuctional appliance fo r 13 months on an average. The position of the mandible, tongue, soft palate,hyo id bone and the radius vector of the upper airway was measured by lateral cepha lometric radiographs, the indexes of sleep condition, breath function and cardio vascular system were measured by polysomnography before and after treatment. Results: At the end of the treatment, the average increase in the radius of upper airway was 4.84 mm (P
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Objective: To examine the skeletal factors of Angle's classⅡdivision 1 malocclusion in order to find a reasonable treatment protocol. Methods: The skeletal factors were measured and compared between 86 cases aged 12～25 years with AngleⅡ 1 malocclusion and 86 cases at the same age with normal occlusion. Thirteen measurements were chosen on lateral cephalometric radiograph for the comparison. Results: In the group of maloculsion, some measurements standing for sagittal skeletal pattern were statistically defferent from those in the group of normal occlusion, such as decreased SNB angle and SL linear and increased ANB angle, whereas some were not significently different, such as the SNA angle and PNS-ANS linear; some measurements standing for the vertical skeletal pattern were statistically defferent, such as decreased UM-PP linear and LM-MP linear and increased UI-PP linear, whereas some were not significently different, such as LI-PP linear;some measurements standing for growth pattern of mandibular were statistically defferent, such as decreased SN-MP angle. Conclusion: There are posterior alveolar defficency and mandibular retroposition as well as counterclockwise rotation of mandile in the patients with Angle class Ⅱ 1 malocclusion. The treatment for Angle Ⅱ 1 malocclusion should be to make mandibular move forward and downward in accordance with the characteristic skeletal pattern.