Maxillary Occlusal Plane Research Articles

3D evaluation of sagittal inclination of the maxillary dentition in relation to facial landmarks: A cohort study.

The determination of the maxillary occlusal plane presents a significant clinical challenge in the treatment of edentulous patients as well as it is critical for complex full-mouth reconstructions in dentate patients, including those with implant-supported rehabilitations. While the use of a Fox plane plate is standard in edentulous cases, its application in dentate patients lacks thorough documentation in existing literature. This clinical study assessed the sagittal position of the maxillary dentition in relation to facial landmarks using a digital three-dimensional analysis and evaluated the suitability and reliability of applying a simulated Fox plane plate, also known as an occlusal plane guide, in dentate patients. Eighty-one subjects were recruited at the Department of Prosthetic Dentistry of Goethe University Frankfurt, Germany, according to specific inclusion criteria. Intraoral and facial scans were obtained and analyzed using GOM Inspect Pro software (GOM, Braunschweig, Germany). The angles between the maxillary occlusal plane and three variations each of Camper's plane and ala-tragus line, relating to superior, middle, and inferior tragus points, were measured. These modified planes were then compared to a plane established by a simulated digital Fox plane plate, which was adapted to the maxillary anterior teeth and the lowest point of the posterior teeth in both quadrants. A total of 81 subjects (58 female and 23 male) with a mean age of 23.9 years were evaluated in this study. No significant angular difference was found between the angles of the maxillary occlusal plane compared with superior Camper's plane, middle Camper's plane, or superior ala-tragus line (p >0.05). The smallest angle occurred between superior Camper's plane and the maxillary occlusal plane on both the right (3.443°) and left (3.535°) sides. The application of a Fox plane plate resulted in two different occlusal planes in 70% of patients, significantly deviating from the digitally determined plane (p <0.05). Superior and middle Camper's planes, along with superior ala-tragus line, can be considered approximately parallel reference planes and are suitable for routine determining of the maxillary occlusal plane in restorative treatments. However, in contrast to digital evaluation methods, the application of a Fox plane plate in dentate patients showed high variability, indicating its low reproducibility due to its ambiguous positioning on the maxillary dentition. Clinical trial registration site: https://drks.de/search/de/trial/DRKS00030166.

Assessment of Bone Thickness at the Infra Zygomatic Crest Region for Various Orthodontic Miniscrew Implant (OMSI) Insertion Angles: A Cone-Beam Computed Tomographic Study.

To evaluate the infrazygomatic crest (IZC) bone and develop guidelines for the optimum placement of orthodontic miniscrew implants (OMSIs) along the distobuccal root of the permanent maxillary first molar. Bone thickness of the IZC region of 50 young adults (25 males and 25 females) aged 18-30 years were evaluated using cone-beam computed tomography images. The infrazygomatic bone thickness along the distobuccal root of the permanent maxillary first molar was assessed at various insertion angles (40° to 75° i.r.t the maxillary occlusal plane) with an increment of 5°. Student's t-test was used to compare the IZC bone thickness and height at the orthodontic miniscrew insertion site for males and females on the right and left sides. The bone thickness of the IZC region above the distobuccal root of the permanent maxillary first molar was estimated between 4.39±0.25 mm and 9.03±0.45 mm for insertion angles from 40° to 75° to the maxillary occlusal plane. The corresponding OMSI insertion heights were 17.71±0.61 mm to 13.69±0.75 mm, respectively, above the maxillary occlusal plane. There were statistically significant gender and side-wise variations in bone thickness at the IZC area and insertion height. The safe position for OMSI placement at the IZC was 13.69-16 mm from the maxillary occlusal plane with an insertion angle between 55° and 75°. These parameters provide the optimum placement of OMSIs along the distobuccal root of the permanent maxillary first molar.

Digital Planning to Enhance Diagnosis and Precision in Correcting Excessive Gingival Display in the Presence of Asymmetrical Maxillary Position: A Case Report.

This case report addresses the treatment of excessive gingival display (EGD) in the context of maxillary asymmetry, zenith irregularities, and occlusal plane inclination. Digital planning was pivotal in formulating a precise treatment strategy by incorporating facial photographs, digital models, and cone-beam computed tomography data. Parameters, including occlusal plane inclination, teeth position, and lip-to-gingival margin relationships, were considered to ensure treatment alignment with the patient's facial characteristics. Notably, during the planning phase, it was evident that the conventional approach using the cementoenamel junction as the apical limit for incisions would result in asymmetry. Consequently, the gingival margin position was defined in accordance with facial and lip features. The chosen treatment, flapless crown lengthening, was tailored to the patient's thin phenotype and guided by measurements derived from digital planning. Postsurgery, the patient experienced a swift and painless recovery. A harmonious smile with a stable gingival margin position was achieved at the 1-year follow-up, seamlessly complementing the patient's facial attributes. This case underscores the importance of personalized EGD treatment and the value of digital planning in enhancing diagnostic accuracy and precise treatment planning, ultimately facilitating optimal treatment strategies.

Clockwise versus counterclockwise rotation in bimaxillary surgery: 3D analysis of facial soft tissue outcomes.

This study aimed to compare facial 3D soft tissue changes in subjects with Class III deformities who underwent bimaxillary clockwise (CW) and counterclockwise (CCW) rotational orthognathic surgery. Asian Class III subjects who completed bimaxillary surgical orthodontic treatments were enrolled and categorized into CW and CCW groups based on maxillary occlusal plane alterations. Preoperative and 9-month follow-up cone-beam computed tomography (CBCT) and 3D stereophotogrammetry were obtained, superimposed, and quantified for skeletal movements and soft tissue changes in six facial regions. Inverse probability of treatment weighting (IPTW) adjusted for potential confounding factors. Thirty-seven subjects were included (CW group, n = 20; CCW group, n = 17). Postsurgical chin volume significantly reduced in the CW group compared to the CCW group (mean difference 6362 mm3; p = 0.037), and intergonial width significantly decreased in the CW group (mean difference 6.2mm; p = 0.005). The postoperative alar width increased by 1.04mm and 1.22mm in the CW and CCW groups, respectively (p = 0.70). However, these changes were not significantly correlated to the direction of MMC pitch. Clockwise rotation of the bimaxillary complex demonstrated a significant advantage in reducing chin volume and intergonial width compared to counterclockwise rotation, leading to a reduced frontal lower face width among Asian Class III subjects.

Finite element analysis of sagittal screw expander appliance in the treatment of anterior maxillary hypoplasia.

The skeletal anterior crossbite is a common malocclusion in clinic. However, there have been no reports on the maxillary sagittal expansion to correct the premaxillary hypoplasia, which greatly influences the facial morphology and masticatory function, using finite element analysis. In the present study, a three-dimensional finite element model of craniomaxillofacial complex with maxillary sagittal hypoplasia is constructed and the treatment for premaxillary hypoplasia by the sagittal screw expander appliance is simulated. The hypoplasia of the left premaxilla is more serious than that of the right and thus the size of the left part of premaxillary expander baseplate is designed to be larger than that of the right part and the loading is applied at 10° leftward to the sagittal plane and 30° forward and downward to the maxillary occlusal plane. The displacements or equivalent stress distributions of the maxilla, teeth and their periodontal ligaments, are analyzed under the loads of 5.0N, 10.0N, 15.0N, and 20.0N. Consequently, as the load increases, the displacements or equivalent stresses of the maxilla, teeth and their periodontal ligaments all increase. Almost the whole premaxilla markedly move forward, downward, and leftward while other areas in the craniomaxillofacial complex remain almost static or have little displacement. The equivalent stress concentration zone of the maxilla mainly occurs around and in front of the incisive foramina. The displacements of left premaxilla are generally greater than those of the right under the loading forces. The maximum equivalent stress on the teeth and their periodontal ligaments are 2.34E-02MPa and 2.98E-03MPa, respectively. Taken together, the sagittal screw expander appliance can effectively open the premaxillary suture to promote the growth of the premaxilla. An asymmetrical design of sagittal screw expander appliance achieves the asymmetric expansion of the premaxilla to correct the uneven hypoplasia and obtains the more symmetrical aesthetic presentation. This study might provide a solid basis and theoretical guidance for the clinical application of sagittal screw expander appliance in the efficient, accurate, and personalized treatment of premaxillary hypoplasia.

A cross-sectional study on three-dimensional compensatory characteristics of maxillary teeth in patients with different types of skeletal Class III malocclusion with mandibular asymmetry.

The purpose of this study was to analyze three-dimensional dental compensation in patients with different types of skeletal Class III malocclusion with mandibular asymmetry, using cone-beam computed tomography (CBCT) and three-dimensional reconstruction measurement technology, thereby providing clinical guidance and reference for combined orthodontic and orthognathic treatment. 81 patients with skeletal Class III malocclusion with mandibular asymmetry were selected in accordance with the inclusion criteria. According to a new classification method based on the direction and amount of menton deviation relative to ramus deviation, patients were divided into three groups called Type 1, Type 2, and Type 3. In Type 1, the direction of menton deviation was consistent with that of ramus deviation and the amount of menton deviation was greater than that of ramus deviation. In Type 2, the direction of menton deviation was consistent with that of ramus deviation and the amount of menton deviation was smaller than that of ramus deviation. In Type 3, the direction of menton deviation was inconsistent with that of ramus deviation. The maxillary occlusal plane (OP), anterior occlusal plane (AOP), and posterior occlusal plane (POP) were measured on reconstructed CBCT images. The vertical, transverse, and anteroposterior distances from maxillary teeth to reference planes and the 3D angles between the long axis of these teeth and reference planes were measured. These dental variables measured from the deviated and non-deviated sides were compared within each group, as well as among each other. Of the 81 patients with asymmetrical Class III malocclusion, 52 patients were categorized in Type 1, 12 patients in Type 2, and 17 patients in Type 3. There were significant differences between deviated and non-deviated sides in Type 1 and Type 3 (p < 0.05). In Type 1, the vertical distances of maxillary teeth on the deviated side were lower than those on the non-deviated side, and AOP, OP, and POP on the deviated side were larger than those on the non-deviated side (p < 0.05). In Type 3, the vertical distances of the maxillary teeth on the deviated side were lower (p < 0.05), and the AOP and OP on the deviated side were larger than those on the non-deviated side. In all three groups, the transverse distances of the maxillary teeth from the mid-sagittal plane on the deviated side were larger than those on the non-deviated side (p < 0.05), and the angles between the long axis of maxillary teeth and the mid-sagittal plane on the deviated side were larger, respectively (p < 0.05). The maxillary teeth on the deviated side were observed to have smaller eruption heights in Type 1 and Type 3. In Type 1, AOP, POP, and OP were greater on the deviated side, while in Type 3, only AOP and OP were greater on the deviated side. The maxillary teeth of patients in all three groups on the deviated side were buccal and buccally inclined. Larger sample observations are still needed to further verify these findings.

Dual-action vertical intraarch technique: A multifocal technique for open bite correction

The dual action vertical intra-arch technique (DAVIT) is an innovative non-compliant multifocal mechanics for open bite correction. It is based on simultaneous posterior intrusion and anterior extrusion, which can occur at similar or different rates according to the patient's needs. This report presents the clinical handling of this innovative mechanics. The occlusal and cephalometric effects of the DAVIT device are shown by the treatment of an open bite Class III malocclusion. Six months after DAVIT placement, the open bite was corrected by increasing the overbite 5.1 mm. Dentoalveolar changes associated with open bite correction with DAVIT included maxillary molar intrusion, maxillary incisor extrusion and palatal tipping, uprighting of maxillary posterior teeth, and maxillary occlusal plane rotation. Maxillary incisor exposure and smile esthetics improved significantly. DAVIT efficiency seems to be associated with its non-compliant multifocal mechanical action, which can be adjusted according to the patient's occlusal and esthetic needs.

Non-Surgical Camouflage Treatment of a Skeletal Class III Patient with Anterior Open Bite and Asymmetry Using Orthodontic Miniscrews and Intermaxillary Elastics

This case report presents the non-surgical orthodontic camouflage treatment of an 18-year-old male patient with skeletal Class III asymmetry and severe anterior open bite. The anterior open bite was corrected by extrusion of the maxillary and mandibular anterior teeth and clockwise and counterclockwise rotation of the maxillary and mandibular occlusal plane, respectively, using intermaxillary Class III elastics between the maxillary posterior buccal miniscrews and mandibular canines and anterior vertical elastics between the maxillary and mandibular canines. Class III dental relationships and dental asymmetry were corrected via unilateral distalization of the mandibular dentition on the left side using a closed coil spring between the buccal shelf screw and hook. The patient’s smile esthetics and dental relationship were improved with a more favorable facial profile, and facial asymmetry was slightly alleviated after orthodontic camouflage treatment. The total treatment time was 15 months. A modified wraparound retainer with a scalloped labial bow, tongue crib, and tooth positioner was used simultaneously to prevent the potential relapse.

Facial Asymmetry Phenotypes in Adult Patients With Unilateral Cleft Lip and Palate and Skeletal Class III Malocclusion Using Principal Component Analysis and Cluster Analysis

The purpose of this study was to classify and characterize facial asymmetry (FA) phenotypes in adult patients with unilateral cleft lip and palate (UCLP) and skeletal class III malocclusion. The samples comprised 52 adult UCLP patients (36 men and 16 women; mean age, 22.43y) who had undergone orthognathic surgery for correction of class III malocclusion. After measurement of 22 cephalometric parameters in posteroanterior cephalograms taken 1 month before orthognathic surgery, principal component analysis was performed to obtain 5 representative parameters [deviation (mm) of ANS (ANS-dev), maxillary central incisor contact point (Mx1-dev), and menton (Me-dev); cant (degree) of the maxillary anterior occlusal plane (MxAntOP-cant) and mandibular border (MnBorder-cant)]. K-means cluster analysis was conducted using these representative parameters. The differences in cephalometric parameters among the clusters were statistically analyzed. The FA phenotypes were classified into 4 types: No-cant-and-No-deviation type (cluster-4, n=16, 30.8%); MxMn-cant-MxMn-dev to the cleft-side type (cluster-3, n=4, 7.7%); Mx-cant-Mn-shift to the cleft-side type (cluster-2, n=15, 28.8%); and Mn-cant-Mn-dev to the noncleft-side type (cluster-1, n=17, 32.7%). Asymmetry in the maxilla and/or mandible were observed in 70% of patients. One third of patients (cluster-2 and cluster-3; sum, 36.5%) exhibited significant cant of MxAntOP induced by cleft and cant or shift of the mandible to the cleft side. Another one third of patients (cluster-1, 32.7%) demonstrated significant deviation and cant of the mandible to the noncleft-side despite cleft in the maxilla. This FA phenotype classification might be a basic guideline for diagnosis and treatment planning for UCLP patients.

A fully digital 1-day technique for fabricating complete dentures based on an existing denture

This technical report describes a fully digital workflow for the design and fabrication of removable complete dentures in a single day. This technique integrates facial and intraoral scans, uses a computer-aided design software program to modify the orientation of the maxillary occlusal plane in the sagittal and frontal planes and evaluate the esthetics and finally produces complete dentures with a clinically acceptable design, simplifying the clinical workflow.

Class II and anterior open bite malocclusion treated with mini-implants, intermaxillary elastics, speech therapy, and retained with a night-wear palatal crib wraparound

The teeth position in anterior open bite malocclusion depends on a balance of pressure between the tongue and lips and the treatment planning should include such variables. The objective of this study was to report an orthodontic case of an adult with maxillary protrusion and anterior open bite treated with skeletal anchorage and intermaxillary elastics. The patient presented a Class II malocclusion with anterior open bite, without a history of non-nutritive habits, and mandibular missing teeth at 54 years old. Mini-implants were inserted in the maxillary molars region to produce distal movement of the maxillary dentition while controlling molar extrusion, and in the mandibular anterior region on the left side to produce mesial movement of posterior teeth. Up and down intermaxillary elastics were worn in the area of the incisors to treat the open bite together with Class II intermaxillary elastics. Cleats were bonded in the lingual surface of the anterior teeth as spurs to the tongue posture. However, the best result on the anterior open bite treatment was coincident with the speech therapy. Normal relationships between the maxillary and mandibular occlusal plane of cusps, correct anterior overbite, and adequate proximal relationships were obtained at the end of treatment. The retention modality to the maxillary arch was daily wear of a removable standard wraparound and a night-time wraparound with the palatal crib. The new technology allows for more effective treatment in adults and speech therapy was helpful to achieve balanced pressure between the tongue and lips.

Occlusal Plane Modification in Clear Aligners Treatment: Three Dimensional Retrospective Longitudinal Study.

The purpose of the present study was to evaluate: (i) maxillary occlusal plane changes after clear aligners therapy with a 3D measurement technique; and (ii) as a secondary outcome, if such changes were correlated to the patient’s 1axilla-mandibular divergence. 3D maxillary models of 32 patients (7 males and 25 females; mean age 22.3 +/− 3.4 year) treated with clear aligners were analyzed. The angle (α) between a reference palatine plane and a maxillary occlusal plane was measured. Five angular cephalometric measurements (NSL/MP; PP-OP; OP-MP; PP-MP; PFH/AFH%) were performed and related to Δα. The subjects were further divided into three groups according to facial divergence. After aligner treatment, Δα increased in hyperdivergent patients and decreased in hypodivergent patients (p < 0.05). Δα showed a significant positive correlation with NSL/MP (rho = 0.44) and negative correlation with PFH/AFH% (rho = −0.53). Aligners treatment produced a counterlockwise rotation of the maxillary occlusal plane, even if this rotation occurs differently depending on divergence.

Complex case treatment: Is there a limit for surgery-first approach?

Are there any limits for Surgery-first approach? the article strives to identify the tenets of effective management of complex cases, such as facial asymmetry, with surgery-first approach. The main purpose of the article is in attempting to itemize prerequisites or determining factors, through various degrees of facial asymmetry severity, for the successful management of facial asymmetry cases. The key factors such as (1) assessment of chin deviation, (2) quantification or discernment of transverse occlusal plane canting, (3) spatial orientation evaluation of differential anterior and posterior region transverse occlusal canting, and (4) contemplations of six degrees of freedom (6DoF) (translation movements combined with rotation axis - pitch, roll and yaw) are evaluated. Furthermore, dental alignment, severity of mandibular and maxillary occlusal (anterior and posterior) plane canting, critical cephalometric parameters, such as, incisor mandibular plane angle, and other vital sub- components of facial asymmetry are analysed, in detail. Subsequently, these are coherently synchronized with the maxillomandibular complex (MMC) rotation surgery during planning for the successful execution of facial asymmetry correction. Additionally, the article describes the (1) usage of orthodontic arch wires, (2) selection criteria of specific surgical osteotomies, and (3) coordination of maxillary and mandibular dentition to establish a transitional or treatable malocclusion. In conclusion, a thorough evaluation of the determining factors, as described in the article, for the correction of facial asymmetry with surgery-first, aid in categorising facial asymmetry cases that require minimal pre-surgical orthodontics or without pre-surgical orthodontic treatment, thereby defining the limits of surgery-first.

Occlusal Plane Changes after Maxillary Molar Distalization Using Temporary Skeletal Anchorages Devices: A Narrative Review and Preliminary Study

Background: We conducted a narrative review of studies analyzing the occlusal and mandibular plane angles after maxillary molar distalization using temporary skeletal anchorage devices (TADs). An original preliminary investigation was conducted on the occlusal and mandibular plane angle changes according to the design of TAD-supported distalization. Methods: We included 51 participants stratified into three groups (buccal TAD, lingual arch TAD, and pendulum TAD) who underwent lateral cephalography before and after treatment. The paired t-test and ANOVA were used to analyze the significant differences among the groups. Results: The pterygoid vertical to maxillary second molar (p &lt; 0.01) significantly differed before and after treatment within each group (group 1, 1.29 ± 1.73 mm; group 2, 2.01 ± 1.46 mm; group 3, 1.12 ± 1.43 mm). The angle between the Frankfort horizontal and anatomical occlusal plane increased by 1.96 ± 2.88° (p &lt; 0.05) and 2.51 ± 2.57° (p &lt; 0.01) in groups 2 and 3, respectively. Conclusions: The measured variables did not significantly differ among the three groups. The Frankfort-mandibular plane angle and functional occlusal plane did not change after maxillary molar distalization. The anatomical occlusal plane is influenced by the anterior teeth and may be unrelated to maxillary molar distalization. Further studies are required to verify the exact relationship between maxillary molar distalization and occlusal plane angle.

Stability of clockwise rotation of the maxillary occlusal plane in skeletal Class III patients treated with two-jaw surgery.

The objective of the study was to investigate the post-surgical stability of clockwise rotation of the maxillary occlusal plane (MXOP) after Le Fort I osteotomy for posterior impaction and advancement, in skeletal Class III patients who had undergone two-jaw orthognathic surgery (2J-OGS). The sample set consisted of 46 patients (18 males and 28 females). Using lateral cephalograms taken at the initial evaluation (T0), before 2J-OGS (T1), after 2J-OGS (T2) and at debonding (T3), the amount of MXOP change (criterion: 2° in ΔMXOP [between T2 and T3]) was used to assign patients to Group 1 (G1, high relapse, -3.09°) or Group 2 (G2, low relapse, -0.99°). Findings were statistically compared between the groups. Compared with G2, G1 exhibited more severe skeletal Class III relationships and a flatter MXOP at T0, a greater increase in ΔANB, and more clockwise rotation of ΔMXOP and ΔFMA between T1 and T2. G1 also showed a greater decrease in ΔANB, higher counterclockwise rotation of ΔMXOP and upward movement of U1 between T2 and T3. Regression analysis yielded the following equation: MXOP (ΔT2-T3)=-0.37 X MXOP (ΔT1-T2) -0.43. The higher the clockwise rotation of the MXOP during 2J-OGS in skeletal Class III patients, the greater the subsequent relapse (counterclockwise rotation) of the MXOP.

Effective approach for improving agummy smile : Upward movement of the maxillary occlusal plane using midpalatal miniscrews and amodified transpalatal arch.

Correction of agummy smile by orthodontic treatment alone has recently become feasible with the use of miniscrews. However, the optimal treatment mechanics remain unclear. Here we cephalometrically evaluated jaw and tooth displacement in cases where agummy smile was improved using alevel anchorage system (LAS). Sixteen patients underwent orthodontic treatment using anLAS consisting of amodified transpalatal arch and midpalatal miniscrews. Cephalometric pretreatment and posttreatment measurements were compared using the paired t‑test to determine significant skeletal and dental changes. The Mann-WhitneyU test was used for nonparametric data. Spearman's rank correlation coefficient was used to evaluate correlations between different variables and the vertical change in prosthion position which was used to indicate the amount of gingival exposure. The changes noted after treatment were intrusion of the maxillary first molars (P < 0.001) combined with only minor extrusion of the mandibular first molars. Suppressed extrusion of the mandibular first molars was significantly correlated with greater upward movement of the prosthion (r = 0.676, P < 0.01). Upward movement of the prosthion was also significantly correlated with intrusion of the maxillary and mandibular incisors, anterior upward movement of the maxillary occlusal plane, and an increase of the SNP angle. Treatment involving the combined use of miniscrews and amodified transpalatal arch resulted in intrusion of the maxillary first molars and maxillary incisors and consequently elevated the maxillary occlusal plane. The results of this study suggest that intruding the maxillary occlusal plane and minimizing mandibular molar extrusion were effective to induce autorotation of the mandible and to improve agummy smile.

A Study for Determining the Inclination of the Occlusal Plane from the Mandibular Functional Trajectory.

Background During the fabrication of prostheses, the putative occlusal plane is generally determined based on morphological criteria such as Camper's plane. There is a possibility that morphological indexes deviate from their original positions over time. The current study investigated whether functional indexes could be used to determine occlusal planes instead of morphological indexes. Objectives The objectives of the present study were to investigate the relationship between the maxillary occlusal plane and mandibular functional trajectory and to consider a method for reconstructing a lost occlusal plane based on functional trajectories. Methods Thirteen healthy dentulous individuals were recruited for the study. Using a jaw motion tracking device with 6-degrees of freedom, the trajectories of the mandibular first molar and incisor during masticatory movement or tapping movements were measured. Results The closing angle of the mandibular first molar to the maxillary occlusal plane was converged and averaged 74.1° just below the intercuspal position, which is the terminal position of masticatory movement. This angle was positively correlated with the closing angle of the incisal point during tapping movement. The regression equation obtained was y = 0.37x + 45.99, where x was the closing angle of tapping movement and y was the closing angle of masticatory movement. Conclusions It was suggested that when determining lost occlusal plane, the occlusal plane can be derived using the closing angle of the incisal point during tapping movement.

Management of Occlusal Cant using intrusion arch: A case report

A canted occlusal plane is the cause of unaesthetic smile, and also represents a challenge, due to the complex orthodontic procedures involved in its treatment. LeFort I osteotomy with asymmetric maxillary impaction is often used to correct this problem. However, canting caused by extruded teeth can be corrected easily with normal orthodontic appliances like intrusion arches. The correction occurs through intrusion of the extruded teeth on one side of the maxilla. A 41-year-old female with canted maxillary occlusal plane was treated in this manner showing the possibility of correcting occlusal plane canting with intrusion arch thus avoiding surgical intervention.

Correction of a prominent premaxilla in a juvenile with a bilateral cleft lip and palate using a novel, hybrid function regulator, the FR-BCPPm, followed by preadjusted fixed appliances: A 20-year follow-up.

A seven-year-old boy with a repaired bilateral cleft lip and palate, presented with a severe skeletal II base and an extremely prominent premaxilla. He had grossly incompetent lips with lower lip trapping, an 18.5-mm overjet, a deep overbite, markedly retroclined lower incisors, bilateral crossbites and 12-mm-wide alveolar gaps together with 6-mm vertical steps between the extruded premaxillary incisors and the posterior teeth. Before the eruption of the permanent canines, there was an urgency to approximate the opposing cleft alveolar margins and to level the split maxillary occlusal plane, in order to facilitate the successful insertion and subsequent consolidation of secondary alveolar bone grafts.A new functional appliance was therefore designed to achieve this objective, which drew components from Fränkel's FR I and FR III function regulators. Together with a couple of novel components, it created a hybrid appliance, namely the function regulator for juveniles with a bilateral cleft and a prominent premaxilla: the FR-BCPPm.The patient was treated with this appliance and a nocturnal headgear at 7-13 years, together with a concomitant quad helix appliance followed by a transpalatal arch and bilateral bone grafts. He was then treated non-extraction up to the age of 17 years with preadjusted fixed appliances to correct his residual, crowded Class II malocclusion.The marked improvement in his occlusion, dentofacial appearance and his perioral function after a decade of treatment was then followed up over 20 years, during which time mild relapse of the incisor overjet and moderate recurrence of the lower anterior misalignment was noted two years after treatment.While no further relapse was observed at the four-year post-treatment review, by 20 years after treatment, a little further misalignment of the lower anterior teeth was noted, half of which was deemed to be attributable to age-related maturation.

Virtual reality technology in the processing of biological images of maxillary protrusion

It was to investigate the application of implant anchorage in the treatment of adolescent maxillary protrusion. Based on virtual reality (VR) technology, a three-dimensional digital model was constructed, and the dual tree complex wavelet transform (DT-CWT) compression sensing algorithm was added in the imaging. An isolated tooth with complete crown and root was taken, 360 full-range photos were taken, and the photos were imported into VR Worx system. Sixty adolescent patients with maxillary protrusion were randomly divided into groups A, B, and C, with 20 cases in each group. In group A, an external arch anchorage was used to slide the anterior teeth. Implant anchorage was used to slide the upper anterior teeth in groups B and C. Patients in group C were familiar with the surgical procedure using a three-dimensional digital model before surgery. After using digital camera and VR Worx software model reconstruction, three groups of patients had good occlusion after correction, but there were differences in anterior and posterior tooth movement control, maxillary occlusal plane, and mandibular plane angle. The treatment time of groups B and C was significantly shorter than that of group A, and the treatment time of group B was slightly shorter than that of group C, the difference was statistically significant (P < 0.05). In summary, the DT-CWT compression sensing algorithm can improve the quality of biological images, and utilize VR technology to build a three-dimensional digital model of teeth, which can improve the therapeutic effect.