Maxillary Arch Distalization Research Articles

Effect of Second and Third Molar Eruption Stages on First Molar and Maxillary Arch Distalization With Modified Palatal Anchorage Plate and Beneslider: A 3D Finite Element Analysis.

To analyze the effects of the maxillary second molar and third molar eruption stages on the distalization of first molars with a modified palatal anchorage plate (MPAP) and Beneslider using three-dimensional (3D) finite element analysis. Six finite element models (FEMs) of individual maxillary molar distalization and six FEM models of en-masse maxillary arch distalization (EMAD) at different stages of the maxillary molar eruption were created from cone-beam computed tomography (CBCT) images of the maxillary complex, and 3D displacements of the maxillary first and second molars were evaluated with MPAP and Beneslider. On individual molar distalization, Beneslider showed first molar distal translation during the second and third molar follicular stages, while MPAP showed distal tipping of the first molar. With EMAD, either of the appliances showed distal tipping of the first molars. There was palatal rolling and extrusion of the first molars. The second molar showed buccal drifting with intrusion, and the incisors showed palatal displacementalong withextrusion. Second and third molar eruption stages had no adverse influence on first molar and en-masse maxillary arch distalization. Beneslider showed distal translation of the first molar, while distal tipping was seen with MPAP.

Quality of occlusal outcome in adult class II patients after maxillary total arch distalization with interradicular mini-screws

BackgroundThe aim of the investigation was to evaluate if a Class II malocclusion in adult patients can be successfully corrected by maxillary total arch distalization with interradicular mini-screws in combination with completely customized lingual appliances (CCLA).MethodsTwo patient groups were matched for age and gender to determine differences in the quality of final treatment outcome. The treatment results of 40 adult patients with a Class I malocclusion (Group 1) were compared with those of 40 adult patients with a moderate to severe Class II malocclusion (Group 2). All patients had completed treatment with a CCLA (WIN, DW Lingual Systems, Bad Essen, Germany) without overcorrection in the individual treatment plan defined by a target set-up. To compare the treatment results of the two groups, 7 measurements using the American Board of Orthodontics Model Grading System (ABO MGS) and linear measurements for anterior-posterior (AP) and vertical dimensions were assessed at the start of lingual treatment (T1), after debonding (T2B), and compared to the individual target set-up (T2A).ResultsA statistically significant AP correction (mean 4.5 mm, min/max 2.1/8.6, SD 1.09) was achieved in Group 2, representing 99% of the planned amount. The planned overbite correction was fully achieved in both the Class I and Class II groups. There was a statistically significant improvement in the ABO scores in both groups (Group 1: 39.4 to 17.7, Group 2: 55.8 to 17.1), with no significant difference between the two groups at T2B. 95% of the adult patients in Group 1 and 95% in Group 2 would meet the ABO standards after maxillary total arch distalization with a CCLA and interradicular mini-screws.ConclusionsCCLAs in combination with interradicular mini-screws for maxillary total arch distalization can successfully correct moderate to severe Class II malocclusions in adult patients. The quality of the final occlusal outcome is high and the amount of the sagittal correction can be predicted by the individual target set-up.

Miniscrew anchorage versus Class II elastics for maxillary arch distalization using clear aligners.

To identify whether intramaxillary miniscrew anchorage could achieve a better maxillary arch distalization effect in clear aligner treatment compared to Class II elastics. Thirty adult patients with Class II dentition who were treated with whole maxillary arch distalization using clear aligners were collected. Either intramaxillary miniscrew anchorage (miniscrew group, n = 17) or intermaxillary Class II elastics (Class II elastic group, n = 13) were used to support maxillary arch distalization. Three-dimensional predicted and achieved displacements, and angular changes of maxillary posterior teeth and anterior teeth, were measured and compared. The achieved distalization efficiency was 36.2%-43.9% in the posterior teeth and the retraction efficiency was 36.9%-49.4% in the anterior teeth. No statistically significant differences were found in maxillary arch distalization efficiency between the groups. The miniscrew group achieved less incisor extrusion and posterior tooth distal tipping than the Class II elastic group. Both groups achieved comparable arch expansion, posterior tooth buccal inclination, and anterior tooth lingual inclination. Intramaxillary miniscrew anchorage and intermaxillary Class II elastics achieved comparable efficiency in maxillary arch distalization. However, the miniscrew anchorage showed better vertical control in anterior teeth and mesiodistal tipping control in posterior teeth.

Analysis of the changes in components of smile after maxillary arch distalization using infra-zygomatic crest (IZC) screws – A cephalometric and photographic study

Objectives: The purpose of this study was to analyze the effects of infra-zygomatic crest (IZC) screws on smile components after maxillary arch distalization. Materials and Methods: The study was conducted on 20 subjects (11 boys and 9 girls) between 19 and 30 years. It was a time-bound study where screening of patients was done based on the inclusion and exclusion criteria for a year. Before placement of orthodontic bone screws (IZC), pre-treatment (T0) photographs, and cephalograms were taken where photographs were analyzed using Makhter’s software. After 6–8 months, post-distalization treatment (T1) photographs and cephalograms were taken and evaluated. Results: Descriptive statistics were used to obtain the mean and standard deviation for continuous data. Paired t-test was performed to analyze the changes in pre- and post-distalization. The categorical data were calculated using the McNemar test. Differences were considered significant if P < 0.05. Inner commissure right and left, smile arc, posterior maxillary dentition visible - left (PMDVL), upper incisal visibility, and gingival showed statistical significance. Conclusion: Maxillary arch distalization using IZC screws was associated with changes in horizontal smile components but mainly in vertical components, reducing the gummy smile, and making the smile esthetically pleasing.

Comparing the Efficiency of Infrazygomatic Crest (IZC) Screws and Conventional Method for Anterior Retraction in Patients Undergoing Fixed Orthodontic Treatment for Class 2 Malocclusion: A Prospective Clinical Study.

Introduction In orthodontic treatment for class 2 malocclusion, conventional approaches involve extracting the upper first premolars and using methods like en masse retraction and extra-oral or intra-oral distalization. However, these often result in unintended forces and adverse effects. Contemporary techniques, such as maxillary arch distalization with mini-implants like infrazygomatic crest (IZC) implants, offer superior outcomes. IZC implants provide a safe, flexible, and effective site for implant placement, achieving a remarkable 93.7% success rate. Power arms enable precise control, allowing orthodontists to apply controlled forces for optimal tooth movement. This study aims to compare cephalometric parameters pre and post treatment using IZC/buccal shelf (BS) screws and conventional retraction, assessing the efficiency of IZC screws in maintaining arch length during teeth retraction. Methods In a split-mouth study at Yenepoya Dental College, 40 orthodontic patients aged 18-35 were divided into control (premolar extraction, anterior retraction) and study (third molar removal, IZC screw distalization) groups. The control group used a nitinol spring/E chain for retraction, while the study group employed IZC screw-assisted en masse distalization. Regular reviews and adjustments occurred, with radiographs and study models assessed after six months for cephalometric parameters and arch length. Results A significant difference was found in U1-SN (degree), L1-Apog (in mm), L1-NB (degree), and L1-NB (in mm) of pretreatment records, whereas all other measurements showed statistically similar values between conventional and IZC groups. Improvement was higher with the conventional group when compared with IZC groups in these measurements due to the extraction of the first premolars rather than third molar extraction and distalization. However, the IZC group also showed statistically significant improvement in cephalometric parameters such as U1-SN (degree), L1-Apog (in mm), L1-NB (degree), and L1-NB (in mm). Conclusion The statistical analysis of radiographic and cast measurements in both the maxilla and mandible demonstrated a significant efficiency of IZC screws in teeth retraction while preserving arch length compared to conventional methods. Nevertheless, to strengthen the findings of our study, additional clinical investigations on IZC screws are warranted.

Effect of Different Anchorage Reinforcement Methods on Long-Term Maxillary Whole Arch Distalization with Clear Aligner: A 4D Finite Element Study with Staging Simulation.

The objective of this study was to examine how various anchorage methods impact long-term maxillary whole arch distalization using clear aligners (CAs) through an automated staging simulation. Three different anchorage reinforcement methods, namely, Class II elastics, buccal temporary anchorage device (TAD), and palatal TAD, were designed. Orthodontic tooth movement induced by orthodontic forces was simulated using an iterative computation method. Additionally, the automatic adjustment of the CA was simulated through the application of the thermal expansion method. The results indicated that the palatal TAD group had the largest retraction of incisors, followed by the buccal TAD group and the Class II elastic group, while the least was in the control group. The largest distal displacements and efficiency of molar distalization for the first and the second molars were noticed in the palatal TAD group. Arch width increased at the molar and premolar levels in all groups. The FEM results suggested palatal TAD had the best performance considering anterior teeth anchorage maintenance, both sagittally and vertically. However, attention should be paid to the possible increasement of arch width.

Skeletal and dentoalveolar changes after total maxillary arch distalization using the casted palatal plate vs. buccal miniscrews: A randomized clinical trial

To evaluate treatment changes after total maxillary arch distalization using the casted palatal plate compared with buccal miniscrews. This was a randomized, parallel, two-arm, single center trial. Participants were young adults with class II dental relationships and normal or horizontal growth patterns. The patients were treated with total distalization of the maxillary arch and were randomly allocated, according to the anchorage devices, between the plate group and the minivis group. The primary outcomes were sagittal, vertical and angular changes of molars and incisors, while the secondary outcomes were skeletal and soft tissue changes. Outcomes were evaluated on lateral cephalograms and blinding of outcome assessment was implemented. A multivariate analysis of Variance (MANOVA) tests were used and Bonferroni correction for multiple comparisons with P<0.001. Forty patients (33 females and 7 males; mean age 20±3.1 years) where enrolled. A significant distalization of U6 was observed in both groups (4.33mm in the plate group and 1.88mm in the miniscrews group). It was combined with significant intrusion and non-significant distal tipping of the U6 in the plate group (1.85mm and 3.10°, respectively), while intrusion and distal tipping were non-significant in the miniscrew group (0.8mm and 2°, respectively). Both groups showed significant retraction and palatal inclination without vertical changes of U1. Only the plate group produced significant reduction of ANB and Wits. Upper and lower lips were retracted and the nasolabial angle increased significantly in both groups. There was no significant main effect of the appliance type on the comparison of treatment effects between the two groups (P=0.623). However, univariate comparisons showed that the plaque group showed greater distalization of the U6 (P<0.001). Both the casted palatal plate and buccal miniscrews can be viable devices for total distalization of the maxillary arch in the treatment of class II patients. The casted plate may be considered when more extensive distalization is required.

Maxillary total arch distalization with infra-zygomatic crest (IZC) bone screws for the correction of skeletal class II malocclusion: A case report

The correction of skeletal malocclusions in orthodontics has always been a contest for clinicians, especially in non-growing individuals, and often necessitates the distalization of maxillary or mandibular skeletal bases. To accomplish this, diverse treatment modalities have been employed by researchers, and the most recent one is the use of extra-alveolar bone screws such as Infra-zygomatic Crest (IZC) implants. Unlike conventional methods such as extraction and orthognathic surgery, this technique is an effective and efficient treatment alternative for predictable total arch distalization in borderline surgical cases, without interfering with the root movements and with minimal dependence on patient compliance. For achieving the displacement of teeth in a bodily controlled manner, an appropriate direction and magnitude of force must be carefully chosen. Therefore, this case report attempts to measure the amount and pattern of maxillary molar distalization using Infra-zygomatic Crest (IZC) implants with long power arms as a workable treatment option, in an 18-year-old female patient with a skeletal Class II pattern, with no extra mini-implants in the anterior region for intrusion.

Efficiency of maxillary total arch distalization using temporary anchorage devices (TADs) for treatment of Class II-malocclusions: A systematic review and meta-analysis

To evaluate the treatment effects and post-treatment stability of the maxillary total arch distalization using TADs during the non-extraction treatment of class II malocclusions. Study involved an electronic search followed by hand searching for randomized and non-randomized clinical studies about maxillary total arch distalization using TADs. After data extraction and risk of bias assessment, meta-analysis was performed for dental, skeletal and soft tissue changes using the Generic-inverse variance approach by use of the mean difference and random-effect model. In total, 1788 articles were identified, 88 full texts were screened and 22 studies were found eligible; 17 of them were included in the quantitative analysis. The means of distalization/distal tipping of the maxillary first molar were 4mm/3.17° in adults, 3.95mm/1.61° in adolescents after treatment with the Modified C-Palatal plate (MCPP), while they were 2.44mm/2.91° with the inter-radicular mini-screws. Both MCPP's treatment in adults and inter-radicular mini-screws resulted in significant intrusion of U6 (1.64 and 0.75mm, respectively), while insignificant extrusion of U6 was resulted in adolescents treated by MCPP. MCPP appliances resulted in palatal inclination/extrusion of maxillary incisors U1 (6.77°/2mm in adults, 7.46°/3.14mm in adolescents). In contrast, inter-radicular mini-screws resulted in less palatal less amount of palatal inclination/insignificant intrusion of U1 (2.42°/0.14mm). MCPP treatment also resulted in significant changes in the skeletal measurements (SNA, ANB, occlusal and mandibular planes). Insignificant differences were found between subgroups in the retraction amount of maxillary incisors, as well as the upper and lower lips. In the follow-up of adolescents treated with MCPP, a significant amount of mesial movement, mesial tipping, and extrusion (2.94mm, 2.84°, and 3.94mm, respectively) was found. However, skeletal and occlusal corrections of the Class II relationship were maintained. Maxillary total arch distalization using TADs can be an effective and stable treatment procedure. However, RCTs or prospective cohort studies are highly recommended to establish a clinical evidence regarding their efficiency.

Treatment effects after maxillary total arch distalization using a modified C-palatal plate in patients with Class II malocclusion with sinus pneumatization

The purpose of this study was to evaluate the treatment effects after molar distalization using modified C-palatal plates in patients with Class II malocclusion with maxillary sinus pneumatization. This study consisted of 70 lateral cephalograms derived from cone-beam computerized tomography images of 35 patients with Class II malocclusion (mean age 22.3 ± 7.4 years) who had undergone bilateral total arch distalization of the maxillary dentition using modified C-palatal plates. The samples were divided into 2 groups according to sinus pneumatization; group 1 (n= 40), cephalograms with sinus pneumatization and group 2 (n= 30) cephalograms without sinus pneumatization. Paired t tests and independent-sample t tests were used to compare the changes in each group and between groups. The distal movement of the maxillary first molars was 4.3 mm for group 1 and 3.5 mm for group 2, with the intrusion of 1.4 mm and 2.5 mm, respectively. There was no statistically significant difference between the 2 groups. Group 1 showed 3.5° of distal tipping of the maxillary second molars, which was significantly greater than the 0.2° in group 2 (P<0.05). The total treatment period, including distalization, was 2.2 years for group 1 and 1.9 years for group 2, but the difference was not significant. There was no significant difference in the amount of distal movement and intrusion of the maxillary first molars between groups 1 and 2. Therefore, these results suggest that regardless of sinus pneumatization, molar distalization using temporary skeletal anchorage devices in Class II patients can be performed as a nonextraction treatment.

Stability of the Maxillary and Mandibular Total Arch Distalization Using Temporary Anchorage Devices (TADs) in Adults

Distalization with temporary anchorage devices (TADs) is commonly used to resolve crowding and to correct molar relationships in non-extraction cases. The purpose of this study was to quantify the treatment effects and post-treatment stability of total arch distalization with TADs in adults and thereby elucidate the clinical effect of this treatment modality. The subjects of the study were 39 adult orthodontic patients treated with total arch distalization with TADs. Lateral cephalograms and dental casts were taken at pretreatment (T0), post-treatment (T1), and the retention period (T2, 29.3 ± 12.8 months) to evaluate the vertical and horizontal movement of teeth, changes of arch width and molar rotation. It was concluded that even though there was a little relapse in the anteroposterior position of the maxillary and mandibular teeth during retention, there was no obvious relapse in the facial profile. Therefore, the total arch distalization can be used in patients with a moderate amount of arch length discrepancy effectively with stable retention.

Digital Photoelastic Analysis of TAD-Supported Maxillary Arch Distalization

The objective of this study was to determine whether the distribution of compressional and tensional stress around tooth roots is influenced by the position of a temporary anchorage device and the length of the retraction hook during the distalization of the maxillary dentition. A photoelastic orthodontic model was made of photoelastic epoxy resin. Six combinations of three retraction hook lengths and two posterior Temporary skeletal anchorage devices (TAD) positions were established. Stress was applied through an elastic chain for each of the combinations. Digital photoelastic stress analysis measured the compression, tensional stress, and direction around the tooth root. Using this novel photoelastic model, we found that the distribution of compressional and tensional stress during the retraction of the maxillary dentition was significantly influenced by the position of the TAD and the length of the retraction hook.

Comparative evaluation of displacement and stress distribution pattern during maxillary arch distalization with Infra Zygomatic Screw- A three dimensional finite element study

This study aimed to evaluate and compare the distribution of stress and displacement of teeth during maxillary arch distalization with IZC (Infra zygomatic crest) screw with two maxillary positions and different lever arm heights. Six three-dimensional finite element models of the maxillary arch were constructed with third molars extracted. Models 1, 2 and 3: IZC 6 (mesial to mesiobuccal root of first molar, 6) with 0mm, 4mm and 8mm lever arm height; Models 4, 5 and 6: IZC 7 (mesial to mesiobuccal root of second molar, 7) with 0mm, 4mm and 8mm, respectively. MBT preadjusted Brackets (slot size 0.022×0.028") were placed over the clinical crown's centre with 0.019×0.025" stainless steel archwire on all six models. Retraction force of 4N was applied with different combinations of IZC screws and lever arm bilaterally using Nickel-Titanium (NiTi) closed coil spring. Then, evaluation of stress distribution, von Mises stress and maxillary teeth displacement were performed using ANSYS 12.1 software. In this study, maximum von Mises stress in alveolar bone (cortical bone) was observed in Model 4 (107.79MPa) at the screw fixation site that was within the optimum limit (135MPa). Different extents of displacements like labiolingual tipping of crown, labiolingual tipping of root, extrusion and intrusion were noticed. The models with 0mm and 4mm lever arm height (models1, 2, 4 and 5) showed more controlled crown and root movements in comparison to 8mm long lever arm models (models 3 and 6). In model 5, a maximum distal movement compared to all other five models was observed. IZC 7 position showed the most favourable results (maximum distalization) with the lever arm height of 4mm. Therefore, the nearer the force to the centre of resistance of the tooth, the greater is distalization. Stresses on the IZC screw decreases when lever arm height increases, in all the models.

Factors associated with the maxillary third molar position after total arch distalization using a modified C-palatal plate in adolescents.

The purpose of this study was to evaluate the long-term position of erupted third molars after maxillary total arch distalization using modified C-palatal plates (MCPPs) in adolescents and to identify factors associated with these positions. Sixty-two third molars (male: 20, female: 42) in Class II patients treated with MCPPs and thirty-nine teeth for the Control group (male: 22, female: 17). Samples were analyzed using panoramic radiographs taken initially (T0), after treatment (T1) and after >3years retention (T2). Third molars were classified as downward (Group A, N=31; males: 12, females: 19) and upward (Group B, N=31; males: 8, females: 23) based on their vertical position after treatment. Analysis of variance and multiple logistic regression analysis were performed. The vertical position of the third molars of Group A, Group B, and the Control showed a 2.2, 3.5 and 2.7mm downward movement at T2. However, there was no difference in the amount of third molar eruption among the groups. Regarding factors affecting the vertical distance of the third molar, Age, C8-OP, ∠8-OP and D7-T at the initial affected vertical position of the third molars after molar distalization (P<.05). Group A and B showed no difference in the third molar eruption during retention after total arch distalization. This study suggests that it might be unnecessary to extract the developing third molar before molar distalization in Class II adolescents.

Total maxillary arch distalization with modified C-palatal plates in adolescents: A long-term study using cone-beam computed tomography

The aims of this study were to evaluate the long-term skeletodental effects, the volume of maxillary tuberosity, and airway space changes after maxillary molar distalization using modified C-palatal plate (MCPP) in adolescents with Class II malocclusion. The sample consisted of 20 adolescent patients (MCPP group; mean age, 12.9±1.0year) who underwent bilateral distalization of their maxillary dentition and 20 subjects as a control group. In the MCPP group, cone-beam computed tomography images were taken before distalization, at the end of the treatment, and during retention with a minimum of a 3-year posttreatment follow up period. Repeated measures ANOVA followed by post-hoc analysis with the Bonferroni test were used to identify significant differences between time points. After the long-term observation period, sagittal skeletal and dental relationships were maintained (there were no significant changes in ANB, occlusal plane angle, and overjet postretention). The vertical skeletal dimension did not change during treatment and was stable at the long-term follow-up (the mandibular plane angle and ANS-Me were relatively well maintained). The volume of the maxillary tuberosity showed no significant change during long-term retention. However, the volume was significantly smaller in the treatment group than in the control group (P<0.0001). There were no significant airway space changes after distalization and the postretention period. In addition, there was no significant difference between the MCPP and control groups. Improved sagittal skeletal and dental relationships because of treatment were maintained in the long-term evaluation. There was no negative long-term effect on airway space associated with the maxillary arch distalization. Therefore, these findings might be beneficial for clinicians in diagnosis and treatment planning for Class II malocclusion in adolescents.

Evaluation of Efficacy of Various Implants in Maxillary Arch Distalization - A Finite Element Analysis

Introduction: Orthodontic correction of Angle’s class II molar relation has, for long, been one of the challenges in orthodontics, with various researchers attempting to correct the class II molar relationship by diverse methods. One of the techniques that has gained popularity in recent times is maxillary arch distalization by infrazygomatic screws and miniscrews. The objective of the study is to measure and compare the amount of maxillary arch distalization and its effects, on adjacent teeth, by varying the positions of mini-implants by Finite Element Analysis.&#x0D; Materials &amp; Method: A standard three-dimensional finite element model was constructed to simulate the maxillary teeth, periodontal ligament, and alveolar process. In this study, three models were prepared. Model-1: The (miniscrews) were placed between upper first and second premolar, and between second premolar and first molar bilaterally. Model-2: Infrazygomatic screws was placed between upper first and second molar bilaterally. Model-3: Infrazygomatic screws was placed on the mesio-buccal root of upper first molar bilaterally. The displacement of each tooth was calculated on x, y, and z axes when 200 gm of force was applied on each side.&#x0D; Result: Maximum amount of maxillary arch distalization was seen when infrazygomatic screws placed between upper first and second molar in model-2. Whereas maximum amount of maxillary arch intrusion and less distalization was observed when miniscrews placed between upper first premolar and second premolar and in between second premolar and upper first molar in model-1. The difference was statistically significant (p=0.005*). There was no bucco-palatal rotation of teeth observed among all three finite element models.&#x0D; Conclusion: Thus infrazygomatic screws and miniscrews are the effective means of maxillary arch distalization for the correction of Class II malocclusion.

Long-term stability of miniscrew anchored maxillary molar distalization in Class II treatment.

To investigate treatment stability of miniscrew-anchored maxillary distalization in Class II malocclusion. This retrospective study included a distalization (n = 19) and a control (n = 19) group; a patient group with minor corrections served the control. Lateral cephalograms of 38 adult patients were taken before (T0), immediately after (T1), and 3-4 years after (T2) treatment. Horizontal and vertical movement and tipping of the maxillary first molars (U6) and central incisors (U1) were measured along with skeletal craniofacial parameters at three time points to compare the two groups regarding the achieved treatment effects and their stability. Total arch distalization therapy led to 4.2 mm of distal movement of U6 without distal crown tipping (0.6° of axis change) and 3.3° of occlusal plane steepening. Over an average retention period of 42 months, maxillary total arch distalization provided high stability of treatment results, showing the same amount of mesial movement (0.7 mm) as the control group. In Class II treatment, miniscrew-anchored maxillary total arch distalization can provide stable distal movement of the maxillary first molars and central incisors.

Correction of Class II Skeletal Malocclusion with an Infra- Zygomatic Crest Bone Screw Approach

Introduction: This case report describes the treatment of a Class II skeletal malocclusion with a prognathic maxilla and retrognathic mandible with severely proclined maxillary incisors and lingually blocked mandibular right lateral incisor withentire maxillary arch distalization and use ofinfra-zygomatic crest bone screws devoid of extraction of premolars. Method: Treatment involved strap-up of a pre-adjusted edgewise appliance, MBT technique (0.022 X 0.028 - inch slot). A non-extraction approach was recommended despite the case warranted premolar extractions. Infra-zygomatic bone screws of length 14mm and diameter 2mm was used for the distalization of the entire maxillary arch. The case was assessed at start of orthodontic treatment (T1) and end of orthodontic treatment (T2). Results: At T2, the severe pre-maxillary prognathism and mandibular anterior crowding with lingually locked right lateral incisor was corrected with the canines and molars finished in Class I relationship. Normal overbite and overjet with a pleasing soft tissue profile was satisfactorily achieved. Conclusion: Infra-zygomatic bone screws can be effectively used as absolute skeletal anchorage to correct Class II skeletal discrepancy with maxillary prognathism and severe proclination of maxillary incisorsdevoid of premolar extractions.

Treatment stability after total maxillary arch distalization with modified C-palatal plates in adults

The purpose of this study was to evaluate skeletal, dentoalveolar, and soft tissue changes at 3years posttreatment in patients with Class II Division 1 malocclusion treated with modified C-palatal plates (MCPPs). The sample consisted of 69 lateral cephalograms of 23 patients Class II Division 1 malocclusion (9 men, 14 women; average age, 20.1years) who underwent bilateral distalization of their maxillary dentition. The lateral cephalograms were taken immediately before the placement of the MCPPs (T1); at the end of orthodontic fixed appliance therapy (T2); and at the posttreatment observation period (3years posttreatment; T3). Twenty-three variables were measured. Repeated measures ANOVA followed by post hoc analysis using Bonferroni test was used to identify significant differences between time points. Maxillary first molars showed a distal movement of 3.44±1.08mm(P<0.001) distal crown tipping of 2.35°±6.74°, and intrusion of 1.42±1.12mm from T1 to T2. However, from T2 to T3, there was an average of 0.41±0.25mm of mesial movement, 0.50±0.46mm of extrusion, and insignificant mesial crown tipping (0.92°±2.46°; P=0.06). The nasolabial angle increased 9.36° ± 6.04° from T1 to T2 (P<0.001) but then decreased 1.55°±1.54° from T2 to T3. MCPPs are a viable treatment option for maxillary total arch distalization with minimal changes in treatment effects 3years posttreatment.

Short-term cone-beam computed tomography evaluation of maxillary third molar changes after total arch distalization in adolescents.

Our objectives were to evaluate changes in the position of maxillary third molars with cone-beam computed tomography images in adolescents after total arch distalization using a modified C-palatal plate (MCPP) and to compare them with the changes in a matched control group. We included 68 maxillary third molars of 40 adolescent patients (mean age, 12.6years). They were divided into MCPP and control groups. Cone-beam computed tomography images were taken before and after molar distalization (mean duration, 14.4months) in the MCPP group and also in the control group (mean duration, 12.9months). The changes in the position, angulation, and rotation of the third molars were assessed, and the volumes of maxillary tuberosity were measured. After distalization, the third molars moved backward (1.2mm) and upward (0.5mm) in the MCPP group with a significant difference (P<0.003), and they moved downward and forward in the control group. The changes in rotation and angulation were insignificant. The volumes of maxillary tuberosity increased in both groups. Maxillary total arch distalization caused unerupted third molars to move backward and upward, with an insignificant difference in the posttreatment volume of maxillary tuberosity. Therefore, it may be possible to perform maxillary total arch distalization in adolescents with unerupted third molars without a germectomy, at least in the short term.