Factors influencing the accuracy of cephalometric prediction of soft tissue profile changes following orthognathic surgery

Changes in three-dimensional nasal morphology according to the direction of maxillary movement during Le Fort I osteotomy

BACKGROUND

Le Fort I (LFI) osteotomy is commonly performed by orthognathic surgeons; however, postoperative changes in nasolabial morphology are of concern. Several factors influence such changes, but it is difficult to accurately predict the postoperative results. This study evaluated the three-dimensional (3D) morphological changes in the nasal region according to the different directions of maxillary movement during LFI osteotomy.

MATERIALS AND METHODS

Forty-one patients who underwent LFI osteotomies were included. All patients were divided into maxilla-up (Group U: 20 patients) and maxilla-forward (Group F: 21 patients) groups. Soft tissue morphologies were determined preoperatively and 3 or 6 months postoperatively using an optical 3D scanner. All datasets were evaluated in terms of volume changes in nine subregions and changes in linear measurements around the nasal area.

RESULTS

Both groups exhibited increased nasal volumes after surgery in the order of the three upper, three central, and three lower subregions. The change in volume of the central nasal region tended to be greater in Group U than that in Group F.

CONCLUSION

We evaluated 3D morphological changes in the nasal region according to the direction of maxillary movement during LFI osteotomy. Group U exhibited a large change in the volume of the central nasal region.

Accuracy of Digital Imaging Software to Predict Soft Tissue Changes during Orthodontic Treatment

This study aimed to evaluate the accuracy of the Digital Imaging software in the prediction of soft tissue changes following three types of orthodontic interventions: non-extraction, extraction, and orthognathic surgery treatments. Ninety-six patients were randomly selected from the records of three orthodontic interventions (32 subjects per group): (1) non-extraction, (2) extraction, and (3) orthodontic treatment combined with orthognathic surgery. The cephalometric analysis of soft tissue changes in both the actual post-treatment and the predicted treatment was performed using Dolphin Imaging software version 11.9. A paired t-test was utilized to assess the statistically significant differences between the predicted and actual treatment outcomes of the parameters (p < 0.05). In the non-extraction group, prediction errors were exhibited only in the lower lip parameters. In the extraction group, prediction errors were observed in both the upper and lower lip parameters. In the orthognathic surgery group, prediction errors were identified in chin thickness, facial contour angle, and upper and lower lip parameters (p < 0.05). Digital Imaging software exhibited inaccurate soft tissue prediction of 0.3-1.0 mm in some parameters of all treatment groups, which should be considered regarding the application of Dolphin Imaging software in orthodontic treatment planning.

Hard and soft tissue shape variation and changes in Class II division 1 malocclusion during orthodontic treatment: a geometric morphometric analysis

BACKGROUND

This study aims to determine the hard and soft tissue shape variation and its changes in Class II division 1 malocclusion before and after orthodontic treatment using Geometric Morphometric Analysis.

METHODS

This retrospective study included 141 pre-treatment and near-end treatment lateral cephalometric radiographs of Class II division 1 malocclusion patients aged 16-40 years with a skeletal II pattern (ANB > 4o). 32 landmarks in Cartesian coordinates were created and identified using MorphoJ software to establish a shape analysis.

RESULTS

The vertical dimensions (hypodivergent to hyperdivergent facial profiles) showed the largest variation in the general shape of hard and soft tissue, followed by the anteroposterior dimensions (mild to severe skeletal II patterns). Variations of lip shape (long to short), lip protuberance (everted to inverted), and nasolabial angle (obtuse to acute) were present. Orthodontic treatment affected the shape of the hard and soft tissue significantly (p < 0.0001). T2 showed significant uprighting of upper incisors (17.5o) and lower incisors (3.7o), improved NLA (8o), an increase in upper lip thickness (1.5 mm), and a reduction in lower lip thickness (0.7 mm) (p < 0.05).

CONCLUSION

Vertical and anteroposterior shape variations were found. Orthodontic treatment had an impact on both hard and soft tissue shapes. Hence, understanding both the hard and soft tissue shape variations and the orthodontic treatment changes is crucial for an accurate diagnosis and treatment plan to achieve a successful outcome and excellent patient satisfaction.

Accuracy in predicting soft tissue changes of orthodontic class III cases using Dolphin® software

OBJECTIVES

The prediction of posttreatment outcomes is conducive to the final determination of ideal therapeutic options. However, the prediction accuracy in orthodontic class III cases is unclear. Therefore, this study conducted exploration on prediction accuracy in orthodontic class III patients using the Dolphin® software.

MATERIALS AND METHODS

In this retrospective study, lateral cephalometric radiographs of pre- and posttreatment were collected from 28 angle class III adults who received completed non-orthognathic orthodontic therapy (8 males, 20 females; mean age = 20.89 ± 4.26 years). The values of 7 posttreatment parameters were recorded and inserted into the Dolphin® Imaging software to generate a predicted outcome, and then the prediction radiograph and actual posttreatment radiograph were superimposed and compared in terms of soft tissue parameters and landmarks.

RESULTS

The prediction showed significant differences with the actual outcomes in nasal prominence (the difference between the prediction and the actual value was - 0.78 ± 1.82 mm), the distance from the lower lip to the H line (0.55 ± 1.11 mm), and the distance from the lower lip to the E line (0.77 ± 1.62 mm) (p < 0.05). Point subnasale (Sn) (an accuracy of 92.86% in the horizontal direction and 100% in the vertical direction in 2 mm) and point soft tissue A (ST A) (an accuracy of 92.86% in the horizontal direction and 85.71% in the vertical direction in 2 mm) were proven to be the most accurate landmarks, while the predictions in the chin region were relatively inaccurate. Furthermore, the predictions in the vertical direction were of higher accuracy compared to the horizontal direction except for the points around the chin.

CONCLUSIONS

The Dolphin® software demonstrated acceptable prediction accuracy in midfacial changes in class III patients. However, there were still limitations for changes in the chin and lower lip prominence.

CLINICAL RELEVANCE

Clarifying the accuracy of Dolphin® software in predicting soft tissue changes of orthodontic class III cases will facilitate physician-patient communication and clinical treatment.

Tissue Expander Followed by Autogenous Bone Graft Versus Autogenous Bone Graft Alone for Mandibular Reconstruction: Quantitative Assessment

BACKGROUND

The use of a tissue expander in maxillofacial intraoral tissue reconstruction is a developing approach, which provide adequate tissue coverage and aesthetics.

OBJECTIVES

The purpose of this study was to quantitatively compare the use of a soft tissue expander in conjunction with autogenous bone graft with bone graft alone for the repair of the mandible's anterior region.

METHODS

The study comprised 24 patients with bone defects in the anterior mandibular region. Patients were divided into 2 groups at random. In group I, expander with bone graft was used, whereas in group II, bone graft was used alone. Volumetric measures of the grafted area was performed using CBCT, and cephalometric evaluations of the anteroposterior and vertical skeletal relationship, as well as the soft tissue profile were recoded. A comparison was made between the 2 groups 6 and 24 months after surgery with P ≤ 0.05 considered significant.

RESULTS

The mean difference in grafted bone volume between the 2 groups was 1.95 cm 3 , indicating a significant difference between the 2 groups ( P = 0.05) with superior group I results. The soft tissue profile of group I demonstrated a considerable improvement and stability of the lower lip, the labiomental sulcus, and the thickness of the soft tissue Pogonion compared with group II.

CONCLUSION

The use of a tissue expander in conjunction with a bone graft resulted in a better soft tissue profile, making it a favored approach in maxillofacial reconstruction.

A Quantitative and Qualitative Clinical Validation of Soft Tissue Simulation for Orthognathic Surgery Planning

The purpose of this study was to perform a quantitative and qualitative validation of a soft tissue simulation pipeline for orthognathic surgery planning, necessary for clinical use. Simulation results were retrospectively obtained in 10 patients who underwent orthognathic surgery. Quantitatively, error was measured at 9 anatomical landmarks for each patient and different types of comparative analysis were performed considering two mesh resolutions, clinically accepted error, simulation time and error measured by means of percentage of the whole surface. Qualitatively, evaluation and binary questions were asked to two surgeons, both before and after seeing the actual surgical outcome, and their answers were compared. Finally, the quantitative and qualitative results were compared to check if these two types of validation are correlated. The quantitative results were accurate, with greater errors corresponding to gonions and lower lip. Qualitatively, surgeons answered similarly mostly and their evaluations improved when seeing the actual outcome of the surgery. The quantitative validation was not correlated to the qualitative validation. In this study, quantitative and qualitative validations were performed and compared, and the need to carry out both types of analysis in validation studies of soft tissue simulation software for orthognathic surgery planning was proved.

Prediction accuracy of Dolphin software for soft-tissue profile in Class I patients undergoing fixed orthodontic treatment

BACKGROUND

Simulation and prediction can facilitate the decision between an extraction versus nonextraction treatment plan. This study aimed to assess the accuracy of Dolphin Imaging software in predicting profile changes in class I borderline cases.

METHODS

In this retrospective study, class I borderline patients (i.e., both extraction and nonextraction treatment plans were possible for them) aged 15-35 years were enrolled. All of the cephalometric analyses were done by Dolphin Imaging software, version 11.8 Premium. The initial cephalograms were superimposed on initial photographs. The final values for the 7 angular and linear landmarks of the upper and lower incisors were extracted from post-treatment cephalograms and inserted in the "Goals" tab of the Dolphin Imaging software. Post-treatment images of patients were simulated. Final post-treatment photographs were superimposed on the simulated pictures. The differences between the real and simulated pictures were calculated in relation to the reference lines. The P value was set at 0.05.

RESULTS

A total of 70 patients (36 with tooth extraction, and 34 without tooth extraction) were included. In the extraction group, the horizontal position of both lips was predicted to be significantly more protruded than it actually was, whereas in the nonextraction group, the only difference between the simulated and actual results was that the vertical position of the lower lip, which was simulated as being more inferior than it actually was.

CONCLUSIONS

Despite the statistically significant differences between the real and simulated pictures, the differences were small and clinically insignificant. Prediction via Dolphin Imaging software can be an appropriate guide in extraction-nonextraction borderline cases.

Accuracy of three-dimensional soft tissue profile prediction in orthognathic surgery

PURPOSE

To evaluate the accuracy of three-dimensional (3D) soft tissue prediction in bimaxillary orthognathic surgery.

METHODS

Cone-beam computed tomographs of 88 patients with class II (n = 46) and class III (n = 42) malocclusions, who underwent bimaxillary orthognathic surgery, were included in this retrospective study. 3D soft tissue prediction and postoperative outcome were compared by using ten landmarks of facial soft tissues. Patients' sex and age were also assessed. Results were analyzed using a mixed model methodology (p < 0.05).

RESULTS

The success criterion adopted was a mean discrepancy of < 2 mm. Most mandibular landmarks indicated a tendency for underprediction with a downward direction in class II patients, with some values > 2 mm. In class III, there was overprediction with a downward direction for the mandibular landmarks, with values < 2 mm. More accurate results were found in female and older patients.

CONCLUSIONS

3D surgical planning showed clinically acceptable results for predicting soft tissues in patients undergoing bimaxillary orthognathic surgery, with more accurate results for class III patients. Although some differences were found when age and sex were interacted, a consistent association between these variables could not be stated. These results support the clinician, as accuracy can provide a strong guide to the surgeon when planning surgical orthodontic treatment.

Orthodontic Intrusion Using Temporary Anchorage Devices Compared to Other Orthodontic Intrusion Methods: A Systematic Review

Objective

To systemically review all clinical trials that evaluate the effectiveness of orthodontic intrusion using bone anchorage devices versus using other orthodontic techniques in adult patients.

Material and Methods

All randomized, controlled clinical trials and prospective studies that compare the use of TADs in intrusion versus alternative devices from the year 2000 to 2019 were searched using various electronic databases. Databases used include Pubmed, Cochrane, Scopus, Lilacs, and ScienceDirect. Selection was initially made by reading the titles and abstracts of potential suitable studies. The final selection was made after reading the full retrieved articles. A methodological score developed by Lagravère was used to assess the quality of evidence. The selection process was illustrated using a PRISMA flow chart.

Results

A total of 3942 articles were retrieved, from which only two randomized clinical trials met the inclusion criteria. This presented a low to medium level of evidence to support the hypothesis that TADs are more effective than other orthodontic intrusion techniques for intruding upper incisors and improving upper incisor to lip relation while eliminating the adverse effect of compromising vertical posterior anchorage. Shorter treatment times and less root resorption were found in the TAD group.

Conclusion

There is insufficient evidence to state that TADs can be used as orthodontic anchorage to effectively intrude the incisors without the need for patient cooperation. Future high quality prospective randomized clinical trials are required.

Accuracy of three-dimensional virtual simulation of the soft tissues of the face in OrtogOnBlender for correction of class II dentofacial deformities: an uncontrolled experimental case-series study

Purpose

To assess whether virtual simulations of the projection of the soft tissues of the face after class II bimaxillary orthognathic surgery, generated from 3D reconstruction of preoperative computed tomography (CT) scans, differed significantly from the actual soft tissue profile obtained in the late postoperative period (beyond 6 months). Secondarily, to validate the accuracy of a free, open-source software suite for virtual soft tissue planning in orthognathic surgery.

Methods

Helical CT scans were obtained pre- and postoperatively from 16 patients with Angle class II malocclusion who underwent bimaxillary orthognathic surgery. A comparative study between soft tissue meshes constructed for surgical simulation (M1) and the actual meshes obtained from postoperative scans (M2) was then performed. To establish the accuracy of 3D facial soft tissue simulation in a free and open-source software suite (OrtogOnBlender-OOB), 17 predetermined anatomic landmarks were measured in M1 and M2 scans after alignment of cranial structures.

Results

The mean error between preoperative simulations and actual postoperative findings was < 2 mm for all anthropometric landmarks. The overall average error for the facial soft tissues was 1.07 mm.

Conclusion

Comparison between preoperative simulation (M1) and actual postoperative findings (M2) showed clinically relevant ability of the method to reproduce actual surgical movement reliably (< 2-mm error). OOB is capable of accurate soft tissue planning for orthognathic surgery, but mesh deformation methods still require improvement.

Trial registration

RBR-88jff9. Retrospectively registered at Brazilian Registry of Clinical trials-ReBec (http://www.ensaiosclinicos.gov.br) May 06, 2020.

Accuracy of computer-aided prediction in soft tissue changes after orthodontic treatment

INTRODUCTION

An accurate prediction in the soft tissue changes is of great importance for orthodontic treatment planning. Previous studies on the accuracy of the Dolphin visual treatment objective (VTO) in predicting treatment results were mainly focused on orthognathic treatment. The accuracy of Dolphin VTO prediction for orthodontic treatment is, however, poorly understood. The aim of this study was to evaluate the accuracy of Dolphin VTO prediction in soft tissue changes after orthodontic treatment by comparing the changes between predicted and actual values.

METHODS

A total of 157 patients were screened for eligibility, and 34 young adult patients (8 males, 26 females; mean age 24.8 ± 3.9 years) were finally included in the study based on the inclusion and exclusion criteria. The landmarks and parameters of the Holdaway soft tissue analysis were used for the cephalometric analyses. The cephalometric tracings of the actual treatment result and the Dolphin predicted treatment outcome were superimposed to calculate the prediction errors. Paired t test was used to compare the statistical differences between the predicted and actual treatment outcomes of the parameters used in the Holdaway soft tissue analysis.

RESULTS

There were significant differences between the predicted and actual values in parameters of the Holdaway soft tissue analysis (P < 0.05). The prediction of the landmarks in the lips region (ie, subnasale, soft tissue A-point, upper lip, lower lip, and soft tissue B-point) was inclined to be overestimated horizontally and underestimated vertically, whereas the prediction of the landmarks belonging to the chin region (ie, soft tissue pogonion, soft tissue gnathion, and soft tissue menton) was inclined to be underestimated horizontally and overestimated vertically. The most accurate prediction was found in the soft tissue A-point, whereas the least accurate one was found in the soft tissue in the chin region. The prediction was relatively more accurate in the vertical direction than in the horizontal direction.

CONCLUSIONS

The Dolphin VTO prediction in soft tissue changes after the orthodontic treatment in patients with bimaxillary protrusion is the most accurate for the soft tissue A-point and the least accurate for the soft tissue chin region.

Orthodontic-Orthognathic Management of a patient with skeletal class II with bimaxillary protrusion, complicated by vertical maxillary excess: A multi-faceted case report of difficult treatment management issues

This case reports the unsuccessful first treatment and the subsequent retreatment of a 35-year old Asian female with a skeletal class II with bimaxillary protrusion, complicated by a deep bite and vertical maxillary excess. This case report highlights the multiple facets of a challenging treatment plan and discusses the ramifications of treatment when treatment does not go as planned. The initial treatment plan consisted of a surgical approach with a maxillary Le Fort I surgery to correct the malocclusion as per the patient's requests without mandibular surgery due to the inherent risk of paraesthesia. The second treatment plan consisted of a bimaxillary surgery with genioplasty. The surgical treatment utilized virtual surgical planning (VSP). The orthodontic treatment was concluded with a corrected overjet and overbite achieving optimum function and balancing the facial profile aesthetically. This case report highlights the need for clear communication of the treatment plan and also the unpredictability of certain treatment outcomes especially when the literature does not provide for definitive conclusions. In addition, it sheds light on the challenge of unpredictable response of soft tissue after surgical treatment and the importance of patient expectations of outcomes. It is hoped that the paper provides a platform for future discussions of difficult malocclusions.

Orthodontic preparation for orthognathic surgery

Orthodontic preparation is critical to the success of orthognathic surgery. Recognition and correction of existing dental compensations allows full correction of skeletal discrepancies. Presurgical orthodontic goals are important to define at the start of treatment and may not always include complete arch leveling or space closure, or ideal interdigitation. Orthodontic preparation dictates the skeletal movements that are possible at the time of surgery. Different malocclusion types have characteristic dental compensations that can be identified and described. Proper planning, monitoring, and communication between surgeon and orthodontist are critical to avoid potential pitfalls in the orthodontic preparation.

Correlation of clinical predictions and surgical results in maxillary superior repositioning

This is a prospective study to evaluate the accuracy of clinical predictions related to surgical results in subjects who underwent maxillary superior repositioning without anterior-posterior movement. Surgeons' predictions according to clinical (tooth show at rest and at the maximum smile) and cephalometric evaluation were documented for the amount of maxillary superior repositioning. Overcorrection or undercorrection was documented for every subject 1 year after the operations. Receiver operating characteristic curve test was used to find a cutoff point in prediction errors and to determine positive predictive value (PPV) and negative predictive value. Forty subjects (14 males and 26 females) were studied. Results showed a significant difference between changes in the tooth show at rest and at the maximum smile line before and after surgery. Analysis of the data demonstrated no correlation between the predictive data and the surgical results. The incidence of undercorrection (25%) was more common than overcorrection (7.5%). The cutoff point for errors in predictions was 5 mm for tooth show at rest and 15 mm at the maximum smile. When the amount of the presurgical tooth show at rest was more than 5 mm, 50.5% of clinical predictions did not match the clinical results (PPV), and 75% of clinical predictions showed the same results when the tooth show was less than 5 mm (negative predictive value). When the amount of presurgical tooth shown in the maximum smile line was more than 15 mm, 75% of clinical predictions did not match with clinical results (PPV), and 25% of the predictions had the same results because the tooth show at the maximum smile was lower than 15 mm. Clinical predictions according to the tooth show at rest and at the maximum smile have a poor correlation with clinical results in maxillary superior repositioning for vertical maxillary excess. The risk of errors in predictions increased when the amount of superior repositioning of the maxilla increased. Generally, surgeons have a tendency to undercorrect rather than overcorrect, although clinical prediction is an original guideline for surgeons, and it may be associated with variable clinical results.

Informed consent in orthognathic surgery

Historically, the patient-doctor relationship has been based on trust. Adequately informing a patient confirms this relationship and fulfills the legal obligation of the physician to inform the patient to the best of his knowledge. Informed consent is the process of providing patients with the realistic and necessary information in a manner which they can understand and recall and allows them voluntarily to make an informed choice on the treatment. In this article, the current knowledge about informed consent in orthognathic surgery is reviewed and discussed.