The Use of Clear Aligners in Multi-Segmental Maxillary Surgery: A Case-Control Study in Cleft Lip and Palate and Skeletal Class III Patients

Background: Maxillary hypoplasia and mandibular asymmetry may be corrected with orthognathic surgery after growth completion. For most stable results, some cases may require segmental Le Fort I osteotomies. Unfortunately, Invisalign's software (6.0 version) still has some inherent limitations in predicting outcomes for complex surgeries. This study explores the potential of aligners, particularly in multiple-piece maxillary osteotomies in both cleft and non-cleft patients. Method: Thirteen patients who underwent pre-surgical treatment with Invisalign were retrospectively matched in terms of diagnosis, surgical procedure, and orthodontic complexity with thirteen patients treated using fixed appliances. Virtual curves following the lower arch were employed to guide the correct pre-surgical positions of the upper teeth with a simple superimposition technique. The amount of impressions required in both groups to achieve satisfactory pre-surgical alignment of the segmented arches was compared. Results: one or no refinement phases were needed in the Invisalign group to reach an acceptable pre-surgical occlusion, while the amount of pre-surgical impressions needed to reach adequate coordination with fixed appliance treatment was slightly higher (p > 0.05). Conclusions: it appears that clear aligner could serve as an effective treatment for individuals necessitating segmental Le Fort I osteotomies when aided by the suggested simple superimposition approach.

Effect of Different Mini Implant Assisted Rapid Palatal Expansion (MARPE) Designs on Maxillary Protraction in Skeletal Class III malocclusion: An FEM Study

Background

Four different designs of mini-implant-assisted rapid palatal expansion (MARPE) and protraction in nasomaxillary complex and mid-palatal sutures in late adolescent skeletal Class III malocclusion were compared using a three-dimensional finite element analysis.

Methods

A finite element model of skull and related sutures was constructed using the computed tomography scan of a 16-year-old female patient with skeletal Class III and ANB of -2°. Four appliance designs: Type I: MARPE with palatal force, Type II: MARPE with buccal force, Type III: Hybrid hyrax with palatal force, and Type IV: Hybrid hyrax with buccal force. Protraction vectors were and analyzed using Ansys software (ANSYS 2021 R2). The displacement pattern of the nasomaxillary structures and the stress distribution in the sutures were examined in all four appliance designs.

Results

All the appliance designs resulted in a forward movement of the maxilla, while Type I and III, which used palatal protraction force, caused the greatest forward displacement. In Type I, II, and III, along with forward movement, a clockwise rotation of maxilla was observed, while in Type IV, an anticlockwise rotation of maxilla was observed. Type I, II, and III resulted in higher stress distribution around the superior structures, while Type IV resulted in less stress distribution around the superior structures of maxilla.

Conclusion

The forward displacement was enhanced when palatal plates were used to protract the maxilla. The effective appliance design for skeletal class III with open bite case was Type I, II, and III and Type IV for deep bite cases.

Observational study investigating the relationship between maxillomandibular characteristics and temporomandibular disc conditions in female patients with a skeletal class III pattern

OBJECTIVES

The objective of this study was to analyze the relationship between maxillomandibular characteristics and the severity of temporomandibular disc displacement in female patients with a skeletal class III (SKIII) pattern.

METHODS

Fifty-seven samples were included in the study. The evaluation of articular disc conditions was conducted using magnetic resonance imaging, while 25 cephalometric variables from lateral and postero-anterior (P-A) cephalograms were measured to determine their maxillomandibular characteristics. The samples were categorized into three groups based on the articular disc conditions: (1) normal disc position (NDP), (2) disc displacement with reduction (DDwR), and (3) disc displacement without reduction (DDwoR). The relationship between the maxillomandibular characteristics and disc conditions was examined through both basic statistical analysis and multivariate analysis using principal component analysis (PCA).

RESULTS

The Kruskal-Wallis and Dunn-Bonferroni tests revealed a significant difference between the groups in terms of the deviation of mandibular characteristics observed on the P-A cephalogram. The DDwoR group exhibited significantly larger menton deviation, ramal height asymmetry index, and total mandibular length asymmetry index compared to the NDP and DDwR groups. Moreover, the PCA successfully extracted all cephalometric variables into eight principal components. Among them, only the principal component related to mandibular asymmetry was able to differentiate the SKIII samples with DDwoR from the other groups.

CONCLUSIONS

The findings of this study highlight a significant relationship between mandibular asymmetry and the severity of disc displacement, particularly DDwoR, in female patients with a SKIII pattern.

Camouflage Correction of Skeletal Class III Severe Open Bite with Tooth Ankylosis Treated by Temporary Anchorage Devices: A Case Report

Tooth ankylosis is a disorder characterized by the fusion of tooth and alveolar bone. This case report describes the treatment of a severe open bite due to tooth ankylosis. A 14-year-old female patient with a chief complaint of masticatory dysfunction was diagnosed with skeletal Class III severe anterior open bite and tooth ankylosis. She visited our university hospital with a chief complaint of an anterior open bite. After the surgical luxation of the ankylosed maxillary right central incisor, the tooth was orthodontically retracted using a nickel-titanium wire. The right mandibular lateral incisor and canine were luxated and retracted using intermaxillary elastics from a temporary anchorage device (TAD), which was inserted in the opposite jaw. During the treatment, skeletal Class III malocclusion deteriorated due to anterior growth of the mandible. Therefore, TADs were inserted into the retromolar pad on both sides of the mandible and retracted into the mandibular dental arch. Although the mandibular right canine was luxated several times, it could not be brought to the occlusal line, and was thus extracted; the extraction space was replaced with a prosthesis. Consequently, a normal overjet and overbite with a straight profile were achieved. Extrusion of ankylosed teeth by intermaxillary elastics from a TAD is a valid treatment option for patients with severe open bites.

Difference in Using Protrusion Face Mask before or after Rapid Palatal Expansion in Skeletal Class III Children: A Preliminary Study

Treatment of third-class malocclusions often presents a challenge for orthodontists. Skeletal disharmony is often associated with dental malposition. There are several therapeutic choices, including the use in combination of transverse expansion of the maxilla with rapid palatal expander (RPE) and posterior-anterior traction with a Delaire face mask (FM). The purpose of the study is to verify whether there are significant differences in the treatment outcome in the case of use of a face mask followed by a palatal expander or with the sequence of these auxiliaries reversed. Subject and Methods: The two groups were both made up of 13 patients, subdivided into group A, i.e., those whose sequence involved the use of extraoral traction first and then the disjunctor, and those with an inverted sequence in group B. Some cephalometric parameters and dento-skeletal characteristics were evaluated pre-treatment (t0) and at the end of therapy (t1). Results: Considering the T1-T0 of group A (Delaire + rapid palatal expander), the evaluation of the results obtained in this work allows us to observe how within group A there is a significant improvement in the Witts and Nanda indices and facial convexity. Group B (treated with the palate disjunctor sequence followed by traction with Delaire's mask) showed a significant improvement in ANB, in AoBo, and AppBpp values and in convexity. The two groups were comparable, and no statistically significant difference was highlighted. Discussion: The early therapy of the third skeletal classes by means of a rapid palate expander and face mask is effective. There is no statistically significant difference in the two groups who performed the therapy in reverse mode. This suggests that the clinician should choose the treatment sequence based on the skeletal and occlusal conditions of their patients at the start of treatment. Conclusion: Early therapy of third skeletal classes with sagittal expansion using a rapid palate expander can be performed earlier or later than posterior-anterior traction with a Delaire mask.

Multi-disciplinary orthodontic camouflage treatment of a severe skeletal class III malocclusion with 1 year follow-up - A case report

Rationale

Orthodontic camouflage serves its purpose in treating mild to moderate skeletal dysplasia and in conditions where the patient is reluctant to opt for orthognathic surgery or when it is contraindicated.

Patient Concerns

A 22-year-old male was concerned about his irregular teeth.

Diagnosis

Angle's dentoalveolar class III malocclusion on class III skeletal on an average mandibular plane angle with anterior crossbite, deep bite, crowding in maxillary and mandibular anteriors, proclined maxillary anteriors and retroclined mandibular anteriors with reverse overjet and congenitally missing 12, 22, palatally impacted 13 and retained deciduous 63 and palatally placed 23.

Treatment

Orthodontic camouflage with a multi-disciplinary approach.

Outcome

Optimal functional and dentofacial aesthetics were achieved by 22 months.

Take-Away Lesson

The limitations of camouflage must be kept in mind and explained to the patient. The biomechanics need to be customized and integrating different specialties helps maximize the treatment benefits.

The Accuracy of Jaws Repositioning in Bimaxillary Orthognathic Surgery in Patients with Cleft Lip and Palate Compared to Non-Syndromic Skeletal Class III Patients

Background: The present study aims to compare the accuracy of jaw repositioning in bimaxillary orthognathic surgery using digital surgical planning in cleft lip and palate patients and in non-syndromic skeletal class III patients in order to investigate if orthognathic surgery achieves different results in the first group of patients. Method: This study included 32 class III adult patients divided into 2 groups: cleft lip and palate (A, n = 16) and non-cleft (B, n = 16). For each patient, a 2D pre-surgical visual treatment objective was performed by the surgeon to predict hard tissue changes, and the surgical outcome was compared with that planned by using cephalometric measurement (ANB, SNA, SNB, Ar-Go-Me, S-Ar-Go). The statistical analysis showed equivalence between obtained and planned results for each measurement both in group A and in group B, but the difference between the planned and the obtained result was smaller in group B regarding ANB angle. Conclusions: Digital surgical planning ensures better predictability of the surgical results and higher accuracy of surgery in complex patients, such as those with cleft lip and palate.

Genes and Pathways Associated with Skeletal Sagittal Malocclusions: A Systematic Review

Skeletal class II and III malocclusions are craniofacial disorders that negatively impact people’s quality of life worldwide. Unfortunately, the growth patterns of skeletal malocclusions and their clinical correction prognoses are difficult to predict largely due to lack of knowledge of their precise etiology. Inspired by the strong inheritance pattern of a specific type of skeletal malocclusion, previous genome-wide association studies (GWAS) were reanalyzed, resulting in the identification of 19 skeletal class II malocclusion-associated and 53 skeletal class III malocclusion-associated genes. Functional enrichment of these genes created a signal pathway atlas in which most of the genes were associated with bone and cartilage growth and development, as expected, while some were characterized by functions related to skeletal muscle maturation and construction. Interestingly, several genes and enriched pathways are involved in both skeletal class II and III malocclusions, indicating the key regulatory effects of these genes and pathways in craniofacial development. There is no doubt that further investigation is necessary to validate these recognized genes’ and pathways’ specific function(s) related to maxillary and mandibular development. In summary, this systematic review provides initial insight on developing novel gene-based treatment strategies for skeletal malocclusions and paves the path for precision medicine where dental care providers can make an accurate prediction of the craniofacial growth of an individual patient based on his/her genetic profile.

Maxillary Development in Patients with Unilateral Cleft Lip and Palate Compared with Individuals Having Skeletal Class I and Class III Malocclusion

AIM

To compare maxillary development of individuals with unilateral cleft lip and palate (CLP) to individuals with skeletal Class I and Class III malocclusions.

STUDY DESIGN

Cephalometric X-ray films from 90 patients (mean age: 13 ± 2.3 years) were used. The number of samples was determined by Power analysis and three groups consisting of 30 patients (Group 1: Skeletal Class I, Group 2: Skeletal Class III, Group 3: CLP) were formed. A total of 13 cephalometric measurements were performed using Dolphin imaging software 11.7. The Kruskal-Wallis and ANOVA tests were used to calculate the differences. The Dunn test and Bonferroni correction were used in paired group comparisons.

RESULTS

SNA, Co-A, A-PTV Horizontal, Na-APog, A-Na-Pog, FH-NA, Sn'-Mx1, MxOP-TVL (p<0.001***), U6-PTV Vertical (p<0.01**), and NaBa PTV-Gn (p<0.05*) values were significantly different between the three groups. There was no significant difference in Na-ANS, FH-NPog, or Mx1 labial-ULA. SNA, Co-A, A-PTV Horizontal, Na-APog, and A-Na-Pog values between the 1st and 2nd groups and between the 1st and 3rd groups (p<0.001***) were significantly different. FH-Na-A, Sn'-Mx1, MxOP-TVL (p<0.001***), and U6-PTV vertical were different between groups 1 and 3 (p<0.01**), while FH-Na-A (p<0.001***), Sn'-Mx1, MxOP-TVL (p<0.01**), A-PTV Horizontal, and A-Na-Pog (p<0.05*) were significantly different between groups 2 and 3.

CONCLUSION

Maxillary development in CLP differs from skeletal Class I but is similar to skeletal Class III. Considering the delay in maxillary development in the CLP patient, maxillary protraction and maxillary expansion are important treatment protocols in the early period.

The Accuracy of Jaws Repositioning in Bimaxillary Orthognathic Surgery with Traditional Surgical Planning Compared to Digital Surgical Planning in Skeletal Class III Patients: A Retrospective Observational Study

Background: Technological progress has led to the transition to digital methods to perform surgical planning and to obtain surgical splints with CAD/CAM technologies. The present study aimed to compare the accuracy of jaw repositioning in bimaxillary orthognathic surgery using traditional and digital surgical planning in skeletal class III patients. Methods: This study included 60 skeletal class III patients divided into two groups based on the method used to perform surgical planning: traditional (T, n = 30) and digital (D, n = 30). For each patient, a 2D presurgical Visual Treatment Objective (VTO) was prepared and the outcome of the surgery was compared with that planned by using determined cephalometric measurements (ANB, SNA, SNB, Ar-Go-Me, S-Ar-Go). Statistical analysis showed that the measurements planned and those obtained after surgery were equivalent in Group D. For Group T, the analysis showed equivalence only for one of the considered measurements (ANB). By comparing the results of the two groups, Group D presented a lower level of error than Group T. Conclusions: Digital surgical planning performed significantly better in terms of accuracy of jaw repositioning than the traditional protocol.

Relationship between pharyngeal airway depth and ventilation condition in mandibular setback surgery: A computational fluid dynamics study

OBJECTIVES

This study aimed to determine the anteroposterior depth (APD) of the pharyngeal airway (PA) where post-operative PA obstruction was predicted, using computer fluid dynamics (CFD), in order to prevent obstructive sleep apnoea after mandibular setback surgery.

SETTINGS AND SAMPLE POPULATION

Nineteen skeletal Class III patients (8 men; mean age, 26.7 years) who required mandibular setback surgery had computed tomography images taken before and 6 months after surgery.

METHODS

The APD of each site of the four cross-sectional reference planes (retropalatal airway [RA], second cervical vertebral airway, oropharyngeal airway and third cervical vertebral airway) were measured. The Maximum negative pressure (Pmax) of the PA was measured at inspiration using CFD, based on a three-dimensional PA model. Intersite differences were determined using analysis of variance and the Friedman test with Bonferroni correction. The relationship between APD and Pmax was evaluated by Spearman correlation coefficients and non-linear regression analysis.

RESULTS

The smallest PA site was the RA. Pmax was significantly correlated with the APD of the RA (r_s  = .628, P < .001). The relationship between Pmax and the APD-RA was fitted to a curve, which showed an inversely proportional relationship of Pmax to the square of the APD-RA. Pmax substantially increased even with a slight reduction of the APD-RA. In particular, when the APD-RA was 7 mm or less, Pmax increased greatly, suggesting that PA obstruction was more likely to occur.

CONCLUSIONS

The results of this study suggest that APD-RA is a useful predictor of good PA ventilation after surgery.

The Elimination of Dental Crowding and Development of a Proper Dental Arch by Maxillary Anterior Segmental Distraction Osteogenesis for a Patient With UCLP

OBJECTIVE

This report describes the case of a male patient with a complete unilateral cleft lip and palate who presented with midface deficiency and an anteroposteriorly constricted maxilla.

DESIGN

Case report Interventions: Correction involved anterior distraction of the segmented maxilla.

RESULTS

The present case demonstrates that elongation of the maxilla with anterior distraction is an effective way to develop a proper dental arch, correct anterior and posterior crowding, and improve a midface deficiency.

Three-dimensional mandibular motion in skeletal Class III patients

OBJECTIVE

The aim of the study was to analyze the characteristics and changes in mandibular condylar motion in patients with skeletal Class III malocclusion.

METHODS

Using a 3D motion analyzer, mandibular movements were recorded in 9 patients with skeletal Class III malocclusion and 22 control subjects with Angle Class I jaw relationships.

RESULTS

Class III patients had a similar interincisor point displacement but a significantly reduced displacement of both condyles on the sagittal and frontal planes, with smaller translation paths than control subjects (right -9.4 mm; left -4.8 mm). The overall condylar rotation component was larger in Class III patients (right +8.8%; left +7.3%). The largest inter-group significant differences were observed in the first 10% of mouth opening, in which Class III patients had a larger rotating component than control subjects (+20%, p < 0.01).

CONCLUSIONS

Condylar motion was reduced in skeletal Class III patients, in particular in the translational path.

Satisfaction of skeletal class III patients treated with different types of orthognathic surgery

The aim of this study was to compare the satisfaction of skeletal class III patients following treatment with three different methods of orthognathic surgery. Eighty-two patients were divided into three groups according to the surgical procedure performed to correct their class III dentofacial deformity, and answered a questionnaire designed to determine the patient's opinion of the aesthetic and functional treatment outcomes. Differences in the patterns of responses to questions in the questionnaire related to satisfaction between the three clinical groups were evaluated by χ(2) and Fisher's exact tests (α=5%). Eighty patients (97.6%) reported being satisfied with the treatment received. There was no significant difference in response patterns among clinical groups when assessing the improvement in facial appearance, chewing, speech, and socialization. Maxillary advancement led to higher levels of improvement in breathing (P<0.0003). Class III patients treated by orthognathic surgery had high levels of satisfaction with the aesthetic and functional outcomes of their treatment.

Premaxillary Distraction Osteogenesis Using an Intraoral Appliance for Unilateral Cleft Lip and Palate: Case Report

OBJECTIVE

Premaxillary distraction osteogenesis was introduced using intraoral devices to correct maxillary hypoplasia and lengthen the alveolar bone horizontally in a patient with unilateral cleft lip and palate.

METHODS

For premaxillary distraction osteogenesis, Le Fort I osteotomy was performed. Vertical osteotomy lines were located distally of the upper right canine and left first premolar to separate the anterior segment of the maxilla. After a 7-day latency period, distraction was allowed to continue for 20 days at a rate of 0.5 mm/d, followed by a 3-month consolidation period. After consolidation, orthodontic treatment and bilateral intraoral vertical ramus osteotomy were performed for the mandibular setback. The implant and prosthodontic treatments were applied to the alveolar ridge area created by the distraction osteogenesis.

RESULTS

The A-point moved 8.0 mm forward during the distraction osteogenesis period, and the recurrence rate was 25% after the retention period. The transverse dimension of the upper arch was expanded during orthodontic treatment. The quality of the alveolar bone created by distraction osteogenesis was acceptable for the prosthodontic implant.

CONCLUSIONS

Premaxillary distraction osteogenesis and arch expansion is an effective treatment strategy, improving function, aesthetics, and stability for cleft patients with multiple missing teeth.

Differences in three-dimensional soft tissue changes after upper, lower, or both jaw orthognathic surgery in skeletal class III patients

The decision is not always straightforward as to which orthognathic procedure is best for a good aesthetic result; three-dimensional imaging has brought new insight into this topic. The aim of this prospective study was to verify objectively whether postoperative changes occur within those regions not directly affected by surgical movements of the underlying jaw bones. The study included 83 young adults with skeletal class III deformities. They were classified into three groups according to the type of surgery: bilateral sagittal split osteotomy set-back of the mandible (BSSO), Le Fort I advancement of the maxilla, or a combination of both. Pre- and postoperative optical scans were registered as regional best-fits on the areas of the foreheads and both orbits. The shell to shell differences were measured and the average distances between the observed regions were calculated. As expected, changes were greatest in the regions where the underlying bones had been moved, but regardless of the operation performed, changes were found over the whole face. Changes in the nose, cheek, and upper lip regions in the BSSO group and in the lower lip and chin region in the Le Fort I group confirmed the concept of the facial soft tissue mask acting as one unit.