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OBJECTIVE@#To evaluate the decompensation effectiveness and alveolar bone remodeling of mandibular anterior teeth after preoperative orthodontic treatment in high-angle patients with skeletal class Ⅱ malocclusion using lateral cephalogram and cone-beam computed tomography (CBCT).@*METHODS@#Thirty high-angle patients with skeletal class Ⅱ malocclusion who had received preoperative orthodontic treatment and orthognathic surgery in Peking University School and Hospital of Stomatology between Ja-nuary 2017 and August 2022 and had taken lateral cephalogram and CBCT before and after preoperative orthodontic treatment were selected. Items were measured with lateral cephalogram including: The lower central incisor (L1)-Frankfort plane angle (L1-FH), the L1-mandibular plane angle (L1-MP), the L1-nasion-supramental angle (L1-NB) and the vertical distance from the incisal edge of lower central incisor to NB line (L1-NB distance), etc. The incidence of dehiscence/fenestration and the length of dehiscence at labial side (d-La) and lingual side (d-Li) were measured using CBCT. Pearson correlation analysis was used to evaluate the correlation between the changes of d-Li of L1 and age, duration of preoperative orthodontic treatment and the cephalometric measurements before preoperative orthodontic treatment to screen out risk factors affecting the periodontal risk of preoperative orthodontic treatment in high-angle patients with skeletal class Ⅱ malocclusions.@*RESULTS@#After preoperative orthodontic treatment, L1-FH, L1-MP, L1-NB and L1-NB distances changed by 11.56°±5.62°, -11.13°±5.53°, -11.57°±5.43° and (-4.99±1.89) mm, respectively, and the differences were all statistically significant (P < 0.05). Among the 180 measured mandibular anterior teeth, 45 cases with labial dehiscence/fenestration before preoperative orthodontic treatment (T0) had no longer labial dehiscence/fenestration after preope-rative orthodontic treatment (T1); 142 cases without lingual dehiscence/fenestration at T0 had lingual dehiscence/fenestration at T1. After preoperative orthodontic treatment, the d-La of lower lateral incisors (L2), lower canines (L3) and lower anterior teeth (L1+L2+L3) decreased by (0.95±2.22) mm, (1.20±3.23) mm and (0.68±2.50) mm, respectively, and the differences were statistically significant (P < 0.05); the d-Li of L1, L2, L3 and L1+L2+L3 increased by (4.43±1.94) mm, (4.53±2.35) mm, (3.19±2.80) mm and (4.05±2.46) mm, respectively, and the differences were statistically significant (P < 0.05). The increase of d-Li of L1 was positively correlated with L1-FH (r=0.373, P=0.042).@*CONCLUSION@#This study showed that high-angle patients with skeletal class Ⅱ ma-locclusion could achieve ideal decompensation effect of mandibular anterior teeth after preoperative orthodontic treatment with bilateral mandibular first premolars extracted, but the lingual periodontal risk of mandibular anterior teeth was increased. This risk could be correlated to L1-FH before preoperative orthodontic treatment, which should be paid more attention in the design of orthodontic-orthognathic surgical treatment.
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Humans , Malocclusion, Angle Class III , Malocclusion, Angle Class II/surgery , Facial Bones , Incisor , Orthognathic Surgical Procedures , Cone-Beam Computed Tomography , MandibleABSTRACT
OBJECTIVES@#This study aimed to conduct a meta-analysis of the efficacy of mandibular advance clear alig-ners with traditional functional appliances as the control group.@*METHODS@#PubMed, Web of Science, Embase, Cochrane Library, China Biomedical Abstracts Database, China Knowledge Network Database, Wanfang Database, and Weipu Database were used in this study. The two groups of researchers screened the literature and extracted data based on the inclusion and exclusion criteria established by PICOS entries, and used the ROBINS-I scale for quality evaluation. Revman 5.4 and Stata 17.0 software were used for meta-analysis.@*RESULTS@#Nine clinical controlled trials were included in this study with a total sample size of 283 cases. No significant difference was found in SNA, SNB, ANB, Go-Pog, U1-SN, Overjet, and other aspects between the invisible group and the traditional group in the treatment of skeletal class Ⅱ ma-locclusion patients; there was a 0.90° difference in mandibular plane angle between the two groups; the growth of the mandibular ramus (Co-Go) in the traditional group was 1.10 mm more than that in the invisible group; the lip inclination of the lower teeth in the invisible group was better controlled, 1.94° less than that in the control group.@*CONCLUSIONS@#The invisible group can better control the lip inclination of the mandibular anterior teeth when guiding the mandible. Furthermore, the mandibular plane angle (MP-SN) can remain unchanged, but the growth of the mandibular ramus is not as good as the traditional group, and auxiliary measures should be taken to improve it in clinical practice.
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Humans , Malocclusion, Angle Class II/therapy , Mandibular Advancement , Orthodontics, Corrective , Orthodontic Appliances, Functional , Mandible , Orthodontic Appliances, Removable , CephalometryABSTRACT
Objective@#To evaluate the effects of non-bracket invisible appliance mandibular advance(MA) on skeletal Class Ⅱ growing patients with mandibular retrusion.@*Methods@#Nineteen skeletal Class Ⅱ growing patients with mandibular retrusion who were treated in the department of stomatology of Changshu traditional Chinese medicine hospital from January 2018 to May 2021 were selected. They had an average age of (12.32±1.51) years old. The treatment group consisted of 10 children who were treated with MA. The control group consisted of 9 children who refused to treat their malocclusion. Cephalometrics of all patients were taken before and after the observation or treatment. The cephalometric data of two groups were analyzed. @*Results@#Compared with the control group, in the treatment gruop SNB angle, L1-NB angle, L1-NB distance, L6-MP distance, Z angle increased significantly (P<0.05);Co-Go distance, Co-Gn distance, SL increased more greatly than the control group; ANB angle, U1-SN angle, U1-NA angle, U1-NA distance, L1-MP distance, FCA angle decreased significantly (P<0.05); SE did not change significantly in the treatment group, but increased significantly in the control group (P<0.05).@*Conclusion @# MA can promote mandibular growth and improve lateral profile. The angle of the lower teeth and the angle of the mandible plane can be controlled by MA appliance.
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Objective@#To investigate changes in the three⁃dimensional position of the maxillary canine during the distal movement of the maxillary first molar by a mini⁃implant combined with a CD appliance.@*Methods@#Ten typodont models of class II malocclusion were selected, and one side was randomly chosen as the experimental group. The CD ap⁃ pliance was bonded to the maxillary canine and first molar of the experimental group, and 1.2 mm stainless steel wire was bent as the anchorage, which was fixed on the model to simulate mini⁃implants implanted in the zygomatic alveolar ridge. Then, 180 g orthodontic force was applied to the canine of the experimental group; the other side was recognized as the control group and was not used for strengthening. Six mini⁃implants were implanted in different parts of the mod⁃ el and used as a reference before and after the experiment. The models were placed in an incubator and heated at 56 ℃ in a water bath for 2 min. The models were scanned before and after thermostatic water bath treatment with a 3⁃shape scanner. Then, the digital models were overlapped through the reference points, and the positions of the canines and first molars were measured before and after the experiment.@*Results@#The sagittal movement distance of the first molar in the experimental group was ( 0.25 ± 0.33) mm, and the vertical movement distance was (0.25 ± 0.28 )mm, which was significantly different from the control group (P < 0.05), while the transverse change was not significantly different (P > 0.05). There was no significant difference in the root position of the first molar in the experimental group (P > 0.05). The lateral and vertical displacement distances of the maxillary canine crown in the experimental group were (4.03 ± 2.11) mm and (1.86 ± 1.01) mm, respectively, which were significantly different from those in the control group (P < 0.001), while the sagittal changes showed no significant differences (P > 0.05). In the experimental group, there was no significant difference in the position of the apex of the maxillary cusp (P > 0.05).@*Conclusion@#Our in vitro study showed that the maxillary canines inclined buccally accompanied by a small amount of intrusion during molar distaliza⁃ tion by a mini⁃implant combined with a CD appliance.
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OBJECTIVE@#To analyze the morphological changes in the upper airway of obstructive sleep apnea syndrome (OSAS) patients treated with oral appliance in skeletal class Ⅱ malocclusion with different vertical features by using cone beam CT (CBCT).@*METHODS@#Thirty-six patients diagnosed with OSAS by polysomnography and daytime sleepiness scale and skeletal class Ⅱ malocclusion were treated with oral appliance for 4 months. The changes based on CBCT in the morphology of glossopharyngeal and palatopharyngeal before and after treatment in OSAS patients with different vertical features were compared.@*RESULTS@#After treatment with oral appliance, the glossopharyngeal and palatopharyngeal morphologies of patients with mild OSAS showed significant changes. After treatment with oral appliance, the glossopharyngeal morphology of all patients showed significant changes (P<0.05). The palatopharyngeal morphology of patients in the lower and average groups also exhibited significant changes (P<0.05). Sagittal changes in the glossopharyngeal measurements of high-angle patients demonstrated significant difference, whereas the other measured values showed no significant difference.@*CONCLUSIONS@#The morphological changes in the upper airway were significant in OSAS patients with lower and average vertical patterns when treated with oral appliance, but the changes in high vertical patterns were not significant.
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Humans , Cone-Beam Computed Tomography , Malocclusion, Angle Class II , Polysomnography , Sleep Apnea, ObstructiveABSTRACT
Class Ⅱ malocclusion is a common orofacial deformity that could harm the facial esthetics and oral function. Two-stage treatment strategy always applies to functional and skeletal (mild and moderate) class Ⅱ malocclusion with man-dibular retrognathism in teenagers. Traditional functional orthopedic appliances are less comfortable and inconvenient to correct the dental arches, making the treatment duration long. With the rapid progress of digital technology and material science, functional clear aligners that offer comfort have emerged. Functional clear aligners can combine orthopedic and orthodontic treatments to correct the jaw relationship and align the dental arch, thereby shortening the treatment duration. This paper emphasizes the treatment key points, and clinical experience of using functional clear aligners.
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Adolescent , Humans , Esthetics, Dental , Malocclusion , Malocclusion, Angle Class II , Orthodontic Appliance Design , Tooth Movement TechniquesABSTRACT
@#For patients with dento-maxillofacial deformities who receive orthodontic-orthognathic combined treatment, the conventional treatment approach is preoperative orthodontic-orthognathic surgery-postoperative orthodontics. However, with the development of techniques used in orthodontic and orthognathic treatment, the surgery-first approach (SFA), namely, orthodontic surgery-postoperative orthodontics, has been widely used currently and displays several advantages, such as improving the treatment efficiency and providing patients with more satisfaction. This review provides a brief discussion and review of SFA concerning its development, indications, advantages and disadvantages, outcomes and stability, and the application and research progress of SFA in orthodontic-orthognathic combined treatment for patients with maxillofacial deformity. The literature review results showed that compared with the conventional treatment approach, SFA has relatively strict indications, which usually include patients with skeletal class Ⅱ/Ⅲ malocclusion, skeletal open bite, and bimaxillary protrusion or patients with facial asymmetry but who require little preoperative orthodontic treatment or removal of the compensation of the dental arch, specifically as follows: ①well-aligned to mildly crowded anterior teeth, ②flat to mild curve of Spee, ③normal to mildly proclined/retroclined incisor inclination, ④acceptable arch coordination, ⑤extensive occlusal contact between the upper and lower dentition requiring at least 3 occlusal contacts. Any occlusion that may affect the outcome of surgery or final result of the overall treatment, as well as any disease that may jeopardize the healing process after surgery, is regarded as a contraindication. Furthermore, SFA has potential disadvantages, such as a possible higher incidence of complications, including unstable occlusion and malunion of bones, which still require further research to be confirmed. Most researchers believe that no significant difference occurs between the outcome and stability of the two approaches. However, currently, we still need a sufficient sample size of prospective studies to provide accurate evidence.
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Objective:To establish the quantitative relationship equation of the crantiofacial vertical points in the skeletal classⅡ malocclusion patients with various vertical types by using genetic algorithms method,and to express the measured values in the patients with different gender with the same formula.Methods:A total of 155 skeletal class Ⅱ malocclusion patients without treatment,aged from 10 to 18 years old,were selected and divided into high-angle group(n=50),average-angle group(n=58),low-angle group(n=47);5 samples were randomly selected in each group as the test samples,the rest as the experimental sample.The cephalometic radiographs were performed and measured.The relevant influencing factors of craniofacial structure were ensured.The genetic algorithm was used to optimize the equation parameters to obtain the correlation equation.The error between the predicted value and the measured value was compared.Results:The various parameters had no significant differences between different gender in high-angle,average-angle and low-angle groups(P>0.05);then the men and the women with same type were combined,most of the indicators had statistically significant differences between three groups (P0.05).Conclusion:The quantitative relationship equation of the crantiofacial vertical points in the skeletal class Ⅱmalocclusion patients with various vertical types established with genetic algorithms may show the vertical quantitative relationship and predict the growth to a certain degree.
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Objective @# To assess the result of treatment in ClassⅡmalocclusion subdivision with unilateral Forsus appliance. @*Methods @#23 patients with ClassⅡmalocclusion subdivision were selected, who were treated with Straight wire fixed appliance in combination with unilateral Forsus appliances while another 27 patients were untreated as control group. Lateral cephalographs were taken before and after the comprehensive treatment, and the indicators of dental, skeletal, and soft tissue profile were measured.@*Results @#The Forsus appliance can correct ClassⅡmalocclusion subdivision through distalizing the upper teeth and moving the lower teeth mesially. Midline can be corrected at the same time. There was a statistically significant difference in the amount of tooth movement (P < 0.05). @*Conclusion @#Forsus appliance is an effective device for treating ClassⅡmalocclusion subdivision, which can induce significant dental and soft tissue changes.
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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 compare the effects between Begg and pre-adjusted appliance on dentofacial morphology in Angle class Ⅱ division 1 extraction cases treated by light archwire technique.Methods:28 cases with Angle class Ⅱ division 1 who needed maximum maxillary incisor retraction were divided into 2 groups (MBT pre-adjusted and Begg group) and treated by light archwire technique.4 first premolars were extracted in all patients.Lateral cephalometric films were analyzed before and after treatment.Results:The upper incisors were intruded (0.18 ± 0.32)mm and (0.77 ± 0.91) mm in pre-adjusted and Begg group respectively (P ＜ 0.05).The other differences of cephalometric analyses between 2 groups were not significant (P ＞ 0.05).Conclusion:The effects were almost same with pre-adjusted and Begg appliances in Angle class Ⅱ division 1 extraction cases treated by light archwire technique except for that the latter is better than the former in vertical control of maxillary anterior teeth.
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Objective:To study the alveolar bone morphology in the anterior teeth area of the skeletal Class Ⅱ malocclusion subjects with different vertical skeletal types.Methods:64 patients with skeletal Class Ⅱ malocclusion and 15 subjects with normal occlusion were included.The alveolar bone structure of the anterior teeth were observed using CBCT.Results:The labial and lingual alveolar bone height and the alveolar bone thickness of the incisors of the patients were much lower than those of the normal controls.The height of labial and lingual alveolar bone and the alveolar bone thickness of anterior teeth in high-angle subgroup were lower than those in low-angle subgroup.Conclusion:The thickness of the anterior teeth alveolar bone of skeletal Class Ⅱ malocclusion is low,espe-cially in the high-angle group.
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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 investigate the effects of corticotomy assisted orthodontic treatment for mild skeletal Class Ⅱ malocclusion. Methods:7 adult patients with mild skeletal Class Ⅱ division 1 malocclusion were included and underwent corticotomy assisted ortho-dontic treatments.3D measurements and analysis of CBCT data before and after treatment were conducted.Results:The average dura-tion of upper anterior teeth retraction was 3.2 months.After treatment,obvious retraction of up incisiors with the retraction of maxillary alveolar bone and the upper lip backward and downward movement were observed.Conclusion:Corticotomy assisted orthodontic treat-ment is effective in the treatment of mild skeletal Class Ⅱ malocclusion by the retraction of uper anterior teeth,alveolarar bone and soft-tissue profile improvement.
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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:To evaluate the clinical effects of Distal-Jet appliance on the distalization of maxillary molar.Methods:12 Class Ⅱ malocclusion patients(at the average age of 12.3 years) with mesially moved maxillary molar were treated by Distal-Jet appliance. Cephalometic radiographs and dental models were taken and analyzed before and after molar distalization.Results:The treatment time was (4.3?2.8) months. After treatment following effects were achieved:①The maxillary molar was distalized by (3.6?0.75) mm per side with crown tilting distally by ( 3.5 ?3)?. ②The first premolar was moved mesially by (2.1?1.7) mm (tilting movement). Anterior overjet was increased by (1.47?1.76) mm. ③In the vertical dimension,the maxillary molar was extruded slightly by (0.39? 0.46 ) mm, the first premolar was extruded by (0.43?0.61) mm. ④The width between the central point of first maxillary molar was increased by ( 2.8 ?1.1) mm.Conclusions:The Distal-Jet appliance can distalize maxillary molars effectively. However,it may result in distaly tilting of molars and mesial movement of premolars.
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objective: To evaluate the effects of the pendulum appliance on arch length, arch width, overbite and overjet. Methods: Pendulum appliances were applied for distalization of maxillary molars in 37 patients whith class Ⅱ malocclusion and 1-Ⅱ degree crowded dentition in upper dental arch. Pretreatment and posttreatment model analysis was conducted. Results: 37 patients treated for 18.2?4.5 weeks with pendulum appliance were accomplished . The increase of arch arc length between the maxillary first molars was (17.36?4.38) mm, the decrease of anterior arch width (-3.04?1.59) mm, and the decrease of posterior arch width (-1.29?2.01) mm . Differences between the pretreatment and posttreatment were significant, including arch arc length between the maxillary first molars ( P
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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 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.
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Objective: To specify what we should notice during the treatment of Class Ⅱ high-angle malocclusions.Methods: 14 patients(8 male and 6 female) with Class Ⅱ high-angle malocclusions were investigated with Tweed-Merrifield morphology analysis.Results: (1)FMIA and Z-angle were increased after treatment(P