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OBJECTIVE@#To evaluate the changes of periodontal phenotype (width of keratinized gingiva, thickness and height of alveolar bone) of lower anterior teeth in patients with skeletal class Ⅲ malocclusion before and after the periodontal-orthodontic-orthognathic combined treatment.@*METHODS@#In the study, 20 patients with skeletal class Ⅲ malocclusion (6 males and 14 females) completed the periodontal-orthodontic-orthognathic combined treatment were included from March 2017 to June 2022, with 39 central incisors, 40 lateral incisors and 40 canines. The mean age was (25.40±4.27) years (20-34 years). The mean follow-up time was (3.70±1.05) years from the beginning of periodontal corticotomy regenerative surgery (PCRS) to the end of the combined treatment. Cone-beam computed tomography (CBCT) was used to measure the thickness, area and height of alveolar bone by the same researcher, taken before the PCRS (T0), 6 months after the PCRS (T1), 12 months after the PCRS (T2), before the orthognathic surgery (T3), and after the periodontal-orthodontic-orthognathic combined treatment (T4). The periodontal clinical parameters were used to evaluate changes in the soft tissue by another researcher, measured before the PCRS (T0) and after the combined treatment (T4). Changes of soft and hard tissue were evaluated by the periodontal phenotype.@*RESULTS@#The width of keratinized gingiva increased significantly (all P < 0.001) in lower anterior teeth, the central incisors, lateral incisors and canines increased by (1.82±1.57) mm, (2.03±1.48) mm and (2.05±1.27) mm, respectively. The proportion of thick periodontal biotype in the central and lateral incisors increased significantly (all P < 0.001), while the changes of periodontal biotypes in the lower canines were not obvious. The thickness of labial alveolar bone of lower anterior teeth all increased significantly after periodontal corticotomy regenerative surgery and the combined treatment (all P < 0.001). The area of labial alveolar bone of lower anterior teeth also increased significantly after the combined treatment (all P < 0.001). The whole area of labial and lingual alveolar bone of central and lateral incisors increased (P < 0.001), while the whole area of canines remained the same. All The height of the alveolar bone increased (all P < 0.001) on the labial side after the treatment.@*CONCLUSION@#The periodontal phenotypes of lower anterior teeth were significantly improved after the periodontal-orthodontic-orthognathic combined treatment in patients with skeletal Angle class Ⅲ malocclusion. The improvement was long-termly stable, and the periodontal risk was reduced.
Subject(s)
Male , Female , Humans , Malocclusion, Angle Class III/surgery , Oral Surgical Procedures , Incisor , Cone-Beam Computed Tomography/methodsABSTRACT
OBJECTIVE@#To assess three-dimensional (3D) changes of circummaxillary sutures following maxillary protraction with alternate rapid palatal expansions and constrictions (RPE/C) facemask protocol in maxillary retrusive children, and to investigate the relationship between the changes of circum-maxillary sutures and zygomaticomaxillary suture (ZMS) maturation, and to explore the factors of maxilla forward movement with RPE/C and facemask.@*METHODS@#In the study (clinical trial registration No: ChiCTR2000034909), 36 maxillary retrusive patients were recruited and block randomized to either the rapid palatal expansion (RPE) group or the RPE/C group. Patients aged 7 to 13 years, Class Ⅲ malocclusion, anterior crossbite, ANB less than 0°, Wits appraisal less than -2 mm, and A-Np less than 0 mm were included in the study. The RPE group received rapid palatal expansion, whereas the RPE/C group received alternate rapid palatal expansions and constrictions, and both with facemask protraction. Head orientations of cone-beam computed tomography (CBCT) images were implemented by Dolphin 11.7. 3D measurements of circummaxillary sutures on CBCT images were evaluated using Mimics 10.01 before (T0) and after treatment (T1). The changes were analyzed with independent t test, two-way ANOVA, Pearson correlation and regression analysis.@*RESULTS@#Two subjects in the RPE/C group were lost to follow-up. A total of 34 patients reached the completion criteria and were analyzed. Compared with the RPE group, sagittal changes of circummaxillary sutures were significantly increased in the RPE/C group with 1.21 mm advancement of zygomaticotemporal suture, 2.20 mm of ZMS, 1.43 mm of zygoma-ticofrontal suture (P < 0.05, respectively). Except for the zygomaticotemporal suture, the rest forward sagittal changes of other circummaxillary sutures showed no major difference in terms of the ZMS maturation. The Spearman's correlation in RPE/C indicated a strong positive correlation of sagittal changes between ZMS and point A (P < 0.01) with a regression analysis R2=42.5%.@*CONCLUSION@#RPE/C might be more effective on the treatment of maxillary retrusive children. As one of the major mechanical loading sutures during orthopedic therapy, ZMS showed a strong positive correlation with point A on sagittal changes.
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Humans , Cone-Beam Computed Tomography/methods , Constriction , Malocclusion, Angle Class III/therapy , Maxilla/diagnostic imaging , Palatal Expansion Technique , SuturesABSTRACT
Objective@#To establish a quantitative three-dimensional method based on intraoral scan to evaluate the changes of soft tissue, and to evaluate the changes of supracrestal gingival thickness (SGT) in skeletal class Ⅲ patients induced by periodontal regenerative and corticotomy surgery (PRCS).@*Methods@#Twenty-two systematically and periodontally healthy skeletal class Ⅲ patients (4 males and 18 females, aged between 19 and 35 years), who were in need of combined orthodontic-orthognathic treatment and referred to the Department of Periodontology from the Department of Orthodontics and the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from January, 2018 to March, 2019, were collected in the study. The teeth involved were 112 anterior teeth (46 maxillary anterior teeth and 66 mandibular anterior teeth). PRCS in anterior tooth area was conducted before orthodontic decompensation. Probing depth (PD), bleeding index (BI) and keratinized gingiva width (KGW) were recorded before surgery and 6 months post-surgery. The intraoral digital impressions of maxillary and mandibular anterior teeth were obtained by 3-shape intraoral scanner before surgery and 6 months after surgery. The Standard Tessellation Language (STL) files were processed using Geomagic qualify 12.2 software to establish the soft tissue morphological measurement model, and to quantitatively analyze the changes of gingival thickness situated 1 to 2 mm apical to the free gingival margin on the median sagittal measurement plane.@*Results@#Probing depth and bleeding index had no significant difference before and 6 months after operation (P>0.05). KGW in 6-month post-operation group [(5.18±2.32) mm] was significantly higher than that in pre-operation group [(4.22±1.43) mm] (P<0.05). Supracrestal gingival thickness situated 1 to 2 mm apical to the free gingival margin also significantly increased 6 months after surgery (P<0.05). The changes of gingival thickness situated 1 to 2 mm apical to the free gingival margin in the upper anterior area were (0.68±0.56) and (1.00±0.69) mm, respectively. The changes in the lower anterior area were (0.38±0.42) and (0.58±0.45) mm, respectively. The gingival changes of the upper anterior teeth were also significantly higher than those of the lower anterior teeth (P<0.01).@*Conclusions@#The described quantitative measurement based on intraoral scan could be an effective method for quantitative evaluation of the changes of soft tissue. PRCS could safely increase the supracrestal gingival thickness as well as KGW in skeletal class Ⅲ patients who were in need of combined orthodontic-orthognathic treatment.
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Objective@#To investigage the three-dimensional changes in condylar position after bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class Ⅲpatients with mandibular deviation using cone-beam CT (CBCT).@*Methods@#Twenty-five skeletal class Ⅲ patients with mandibular deviation were included. The patients (12 males and 13 females, aged 19-25 years, average age 22.4 years) were treated in the Department of Orthodontics, Affiliated Stomatological Hospital, Nanchang University from October 2013 to March 2017. The patients were divided into T1, T2 and T3 groups (T1 group: CBCT taken within 1 week before operation; T2 group: CBCT taken within 1 week after operation; T3 group: CBCT taken 6-8 months after surgery). Three sets of image data of condyles on both sides (deviation side and contralateral side) were obtained. After the DICOM data collection, the software of Mimics 17.0 was used to perform three-dimensional reconstruction and condylar position measurements: the distance from the condylar top (CoT) to the standard horizontal plane (SHP), the middle sagittal plane (MSP) and the sella coronal plane (SCP) (CoT-SHP, CoT-MSP, CoT-SCP); the distance from the condylar center (CoC) to SHP, MSP and SCP (CoC-SHP, CoC-MSP, CoC-SCP); the angle from the condyle cella plane (CCP) to SHP, MSP and SCP (CCP-SHP, CCP-MSP, CCP-SCP); the angle from the condyle sagittal plane (CSP) to SHP, MSP and SCP (CSP-SHP, CSP-MSP, CSP-SCP) and the distance of the anterior, superior, posterior, medial, central and lateral joint space. One-way ANOVA and LSD-t test were used to compare the changes in condylar position at different periods (T1, T2, and T3).@*Results@#Within 1 week before operation on the deviation side, CoT-SHP [(2.5±1.3) mm], CSP-MSP (41.2°±8.4°) and the posterior joint space [(2.0±0.6) mm] were obviously increased (P<0.05), and CoT-SCP [(9.1±3.3) mm], CCP-MSP (78.2°±5.2°) were decreased significantly (P<0.05); on the contralateral side, CoT-MSP [(50.4±3.1) mm], CCP-MSP (80.6°±6.0°), the anterior joint space [(2.2±0.6) mm] and the medial joint space [(2.6±0.6) mm] were obviously increased (P<0.05), and CCP-SCP (11.4°±8.8°) were decreased significantly (P<0.05). Six to eight months after surgery, CoT-SHP [(2.2±1.0) mm] and the posterior joint space [(1.9±0.5) mm] on deviation side and CoT-SCP [(8.4±2.8) mm] on the contralateral side were increased significantly (P<0.05). No significant difference was found in other measurements (P>0.05).@*Conclusions@#The condylar position in skeletal class Ⅲ patients with mandibular deviation was asymmetrical. Within 1 week after the operation of BSSRO, the condyle on the deviation side was moved forward, downward and inward. Meanwhile, the condyle on the contralateral side was moved backward and outward. Six to eight months after surgery, the condylar position on both sides was gradually restored to the pre-operative condylar position.
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Objectives@#To investigate the compensation of upper first molar in adult skeletal class Ⅲ patients.@*Methods@#The sample consisted of 48 skeletal class Ⅲ patients with orthodontic-surgical treatment from February 2011 to January 2015 in Peking University School and Hospital of Stomatology. They were allocated into 2 groups based on extraction, 28 patients in extraction group and 22 patients in non-extraction group. Dental casts were taken before and after treatment, and all the casts were scanned with a computer-assisted three-dimensional (3D) scanning system. Acquired 3D data were analyzed by Rapidform 2006. The tip and torque of the upper first molar were measured and analyzed.@*Results@#The tip and torque of the upper first molar in the skeletal class Ⅲ patients after treatment had no difference between extraction group and non-extraction group (P=0.150, P=0.144). The torque of upper first molar in extraction group [-3.32° (-5.10°, 1.16°)] before treatment was bigger than that in non-extraction group [-6.94° (-13.06°, -0.42°)] (P=0.005), and the inclination of upper first molar in extraction group was more obvious.@*Conclusions@#In skeletal class Ⅲ patients, the upper first molar inclined buccally to compensate the discrepancy and extraction was usually necessary for decompensation.
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Objective:To investigate the compensation of the anterior alveolar bone thickness in skeletal class Ⅲ patients treated with orthodontic-surgical treatment.Methods:The samples consisted of 54 ske-letal classⅢpatients treated with orthodontic-surgical treatment.Lateral cephalograms were taken before treatment.Descriptive statistics were calculated for corresponding variables,and the differences between the samples and the norms from Peking University normal occlusion sample library were assessed by inde-pendent-sample t test.Correlation analyses were performed to find associations between skeletal charac-teristics and anterior alveolar bone thickness.According to skeletal anteroposterior discrepancy/vertical type (ANB,criteria=-4°;SN-MP,criteria=37.7°),the samples were allocated into group A (severe anteroposterior discrepancy/hypodivergent vertical type,n=1 1 ),group B (moderate anteroposterior dis-crepancy/hypodivergent vertical type,n=1 6),group C (severe anteroposterior discrepancy/hyperdiver-gent vertical type,n=1 4),and group D (moderate anteroposterior discrepancy/hyperdivergent vertical type,n=1 3),and one-way ANOVA with SNK multiple comparison test were performed.Results:The anterior alveolar bone thickness of the skeletal class Ⅲ patients were thinner compared with norm values (P<0.05 ).Correlational analyses showed that,both the upper and lower anterior alveolar bone thick-ness was correlated with the skeletal vertical discrepancy (P<0.05 ),but the anteroposterior type was only correlated with the lower anterior alveolar bone thickness (P<0.05).For the 4 groups according to skeletal anteroposterior discrepancy/vertical type,hypodivergent vertical type had thinner lower ligual and total bone thickness (LP,LW,P<0.05).while for upper alveolar bone thickness (UW),group C and group B exhibited the thinnest and thickest (the values of UW were 7.86 mm and 9.05 mm).Conclusion:The upper and lower anterior alveolar bone thickness of skeletal classⅢpatients are thinner compared with normal occlusion.Different skeletal anteroposterior discrepancy/vertical type results in differences in the anterior alveolar bone thickness,so decompensation should be treated differently and carefully.
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Objective:To investigate the effect of segmental Le FortⅠosteotomy and bilateral sagittal split ramus osteotomy ( BSSRO ) on the condyle position in skeletal class Ⅲ malocclusion patients . Methods:In this retrospective study , 19 patients with skeletal class Ⅲmalocclusion who met the inclu-sion criteria were enrolled .All the patients underwent the segmental Le FortⅠ osteotomy and BSSRO . Cone beam computed tomography ( CBCT) scans were performed in the following phases:T1:within one week before the surgeries;T2:within one week post-surgery;T3:three months post-surgery;T4:6 to 14 months post-surgery .The posterior spaces , anterior spaces and the superior spaces of the bilateral tem-poromandibular joints were measured according to the Kamelchuk method respectively .The fossa ratios of the condyle and the distribution of the condyle positions related to the glenoid fossa ( anterior , concentric and posterior position ) were calculated .The results were analyzed statistically .Results:The posterior space , the anterior space and the superior space of bilateral temporomandibular joints in T 2 phase [ right:(2.78 ±1.23) mm, (2.47 ±0.89) mm, (3.07 ±0.85) mm; left: (2.93 ±0.83) mm, (2.69 ± 1.14) mm, (3.44 ±1.16) mm] showed significantly larger spaces than those in T 1 phase [right:(1.81 ±0.95) mm, (1.65 ±0.55) mm, (2.13 ±0.52) mm;left:(2.12 ±1.05) mm, (1.79 ±0.59) mm, (2.15 ±0.93) mm],in T3 phase [right:(2.08 ±1.25) mm, (1.79 ±0.68) mm, (1.80 ±0.76) mm;left: (2.05 ±0.75) mm, (1.99 ±0.94) mm, (2.14 ±0.71) mm] and in T4 phase [right:(1.94 ±0.77) mm, (1.81 ±0.69) mm, (2.05 ±0.69) mm;left:(1.89 ±0.69) mm, (1.80 ±0.61) mm, (2.19 ±0.75) mm], P0.05).The fossa ratio and the condyle position related to the glenoid fossa had no significant difference in all the four phases (P>0.05).The results suggested that the condyle moved downward in T 2 phase and changed to the original pre-surgery position in T3 phase, then keot stable in T4 phase.Conclusion:Segmental Le FortⅠ osteotomy and BSSRO caused significant and transient changes of the condyle position in skeletal class Ⅲmalocclusion patients . However , the condyle tended to move back to the original pre-surgery position and might keep stable .
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Objective To evaluate incisor root resorption of adults with skeletal classⅢmalocclusion through three-dimensional reconstruction of cone beam computed tomography (CBCT) image using interacting medical imaging control sys?tem (Mimics) and then offer guidance for labially tilted angle control in orthodontic treatment and distance of bone moving in surgery. Methods Adults of skeletal class Ⅲ malocclusion (n=30) who underwent orthodontic-orthognathic combination treatment were included in this study. CBCT images were then reconstructed three-dimensionally using Mimics 10.01. Each incisor were separated at cementum-enamel junction as crown and root. Labially tilted angle and root volumes of each inci?sor were measured before and after operations. At last, the correlativity between root resorption and labially tilted angle was calculated through statistic analysis. Results The decrement of upper, lower and front incisors’root volumes upon treat?ment is statistically significant. However, there is no statistically significant difference of incisor ’s root volumes among eight incisors nor between different gender. There is linear correlation between root volumes and labially tilted angle when the lat?ter changes 7° or more when they followed the fomular =-21.416+5.618X. Conclusion For adults with skeletal classⅢmalocclusion, orthodontic treatment before orthognathic surgery decrease incisor root volumes when labially tilted angle changes 7° or more.
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Objective:To evaluate facial soft tissue 3-deminsion changes of skeletal Class Ⅲmalocclu-sion patients after orthognathic surgery using structure light scanning technique .Methods:Eight patients [3 males and 5 females, aged ( 27.08 ±4.42 ) years ] with Class Ⅲ dentoskeletal relationship who underwent a bimaxillary orthognathic surgical procedure involving advancement of the maxilla by Le FortⅠosteotomy and mandibular setback by bilateral sagittal split ramus osteotomy (BSSO) and genioplasty to correct deformity were included .3D facial images were obtained by structure light scanner for all the patients 2 weeks preoperatively and 6 months postoperatively .The facial soft tissue changes were evalua-ted in 3-dimension.The linear distances and angulation changes for facial soft tissue landmarks were ana-lyzed.The soft tissue volumetric changes were assessed too .Results: There were significant differences in the sagittal and vertical changes of soft tissue landmarks .The greatest amount of soft tissue change was close to lips.There were more volumetric changes in the chin than in the maxilla , and fewer in the forehead .Conclusion: After biomaxillary surgery , there were significant facial soft tissue differences mainly in the sagittal and vertical dimension for skeletal Class Ⅲ patients .The structure light 3 D scan-ning technique can be accurately used to estimate the soft tissue changes in patients who undergo orthog-nathic surgery .
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Objective To evaluate the treatment effects of double parabolic lingual springs appliance and straight wire appliance therapy in skeletal class Ⅲ malocclusion. Methods 12 cases with skeletal class Ⅲ malocclusion were treated by double parabolic lingual springs appliance and straight wire appliance, cephalometric tracing measurement were taken in analysis,compared between pretreatment and posttreatment in each case. Results The comparison of before and after orthodontic treatment showed angle SNA increased by 2.80°, angle SNB decreased 1.39°ANB decreased by 4.88°. Conclusion The above metioned technique could be a reliable way to treat mild and moderate skeletal class Ⅲ malocclusion.