Accuracy of video imaging for predicting the soft tissue profile after mandibular set-back surgery

Accuracy of Dolphin Imaging software in predicting soft tissue changes of Class II Division 1 incisor relationship treated by all first premolar extraction compared with post-treatment lateral cephalogram

BACKGROUND

To quantify the accuracy of Dolphin Imaging software in predicting soft tissue changes of Class II Division 1 incisor relationship treated by all first premolar extraction compared with actual changes.

METHODS

Pretreatment and post-treatment lateral cephalograms of 30 young adult subjects (25 females and 5 males; age range of 16 to 21 years) were imported and traced in Dolphin Imaging software (version 11.95). Tracings of actual treatment results and the Dolphin predicted treatment outcome were superimposed to calculate the prediction errors. The mean difference for the Holdaway soft tissue analysis and at each landmark was measured in both the X and Y axes. Paired t test was used to compare the statistical differences in Holdaway soft tissue analysis parameters.

RESULTS

There were significant differences between the predicted and actual values in three parameters of the Holdaway soft tissue analysis (P < 0.05). The overall accuracy of estimation was better in vertical direction than horizontal. Prediction of upper and lower lip landmarks was overestimated horizontally and underestimated vertically, whereas that belonging to chin was underestimated horizontally and overestimated vertically. Soft tissue nasion and soft tissue A-point were most accurately predicted, whereas the least accuracy was found in soft tissue chin region.

CONCLUSIONS

Dolphin Imaging Software (version 11.95) can be accurate enough for use in patient communication and education but should be used with caution. It is most accurate in predicting soft tissue changes in the nasion and A-point regions, but least accurate in chin region.

The Accuracy of Computer-Assisted Surgical Planning in Predicting Soft Tissue Responses After Le Fort I Osteotomy: Retrospective Analysis

PURPOSE

Mismatch between preoperative planning and surgical outcome in maxillofacial surgery relate to on-table replication of presurgical planning and predictive algorithm inaccuracy: software error was hereby decoupled from planning inaccuracy to assess a commercial software. The hypothesis was that soft tissue prediction error would be minimized if the surgical procedure was replicated precisely as planned and is independent of the extent of bone repositioning.

MATERIALS AND METHODS

Cone-beam computed tomography scans of 16 Le Fort I osteotomy patients were collected at Boston Children's Hospital. Preoperative and postoperative models of bone and soft tissue were constructed and the maxilla repositioning was replicated. Each model was subdivided into 6 regions: mouth, nose, eyes, and cheeks. Soft tissue prediction (performed using Proplan CMF-Materialise) for each patient was compared with the relative postoperative reconstruction and error was determined. P <0.05 was considered significant.

RESULTS

Le Fort I segment repositioning was replicated within 0.70±0.18 mm. The highest prediction error was found in the mouth (1.49±0.77 mm) followed by the cheeks (0.98±0.34 mm), nose (0.86±0.23 mm), and eyes (0.76±0.32). Prediction error on cheeks correlated significantly with mouth ( r =0.63, P < 0.01) and nose ( r =0.67, P < 0.01). Mouth prediction error correlated with total advancement ( r =0.52, P =0.04).

CONCLUSIONS

ProPlan CMF is a useful outcome prediction tool; however, accuracy decreases with the extent of maxillary advancement even when errors in surgical replication are minimized.

The accuracy of a three-dimensional face model reconstructing method based on conventional clinical two-dimensional photos

Background

This study aims to investigate the accuracy of a three-dimensional (3D) face reconstruction method based on conventional clinical two-dimensional (2D) photos.

Methods

Twenty-three patients were included, and Character Creator v3.2 software with the Headshot v1.0 plugin was used for 3D face model reconstruction. Various facial landmarks were finely adjusted manually to refine the models. After preprocessing and repositioning, 3D deviation analysis was performed. The accuracy of the landmarks in different dimensions was determined, and twelve facial soft tissue measurements were compared to validate the clinical potential of the method.

Result

The reconstructed 3D face models showed good facial morphology with fine texture. The average root mean square errors between face scan models and reconstructed models at perioral area (1.26 ± 0.24 mm, 95%CI: 1.15–1.37 mm) were significantly smaller than the entire facial area (1.77 ± 0.23 mm, 95%CI:1.67–1.88 mm), P < 0.01. The deviation of menton of soft tissue was significantly larger than pronasale (P < 0.01). The deviations of all landmarks in the Y-direction were significantly larger than those in the other 2 dimensions (Y > Z > X, P < 0.01). A significant difference (P < 0.05) of approximately 1.5 mm was found for facial height. Significant differences (P < 0.05) were also identified in the remaining 6 soft tissue measurements, with average deviations no greater than 0.5 mm (linear measurement) or 1.2° (angular measurements).

Conclusion

A 3D face modeling method based on 2D face photos was revealed and validated. The reconstruction accuracy of this method is clinically acceptable for orthodontic measurement purposes, but narrow clinical indications and labor-intensive operations remain problems.

Accuracy of Three-Dimensional Soft-Tissue Prediction Considering the Facial Aesthetic Units Using a Virtual Planning System in Orthognathic Surgery

Virtual surgical planning (VSP) is commonly used in orthognathic surgery. A precise soft-tissue predictability would be a helpful tool, for determining the correct displacement distances of the maxilla and mandible. This study aims to evaluate the soft-tissue predictability of the VSP software IPS CaseDesigner^® (KLS Martin Group, Tuttlingen, Germany). Twenty patients were treated with bimaxillary surgery and were included in the study. The soft-tissue simulation, done by the VSP was exported as STL files in the engineering software Geomagic Control X^TM (3D systems, RockHill, SC, USA). Four months after surgery, a 3D face scan of every patient was performed and compared to the preoperative simulation. The quality of the soft-tissue simulation was validated with the help of a distance map. This distance map was calculated using the inter-surface distance algorithm between the preoperative simulation of the soft-tissue and the actual scan of the postoperative soft-tissue surface. The prediction of the cranial parts of the face (upper cheek, nose, upper lip) was more precise than the prediction of the lower areas (lower cheek, lower lip, chin). The percentage of correctly predicted soft-tissue for the face in total reached values from 69.4% to 96.0%. The VSP system IPS CaseDesigner^® (KLS Martin Group; Tuttlingen, Germany) predicts the patient’s post-surgical soft-tissue accurately. Still, this simulation has to be seen as an approximation, especially for the lower part of the face, and continuous improvement of the underlying algorithm is needed for further development.

Deep Learning-Based Prediction of the 3D Postorthodontic Facial Changes

With the increase of the adult orthodontic population, there is a need for an accurate and evidence-based prediction of the posttreatment face in 3 dimensions (3D). The objectives of this study are 1) to develop a 3D postorthodontic face prediction method based on a deep learning network using the patient-specific factors and orthodontic treatment conditions and 2) to validate the accuracy and clinical usability of the proposed method. Paired sets (n = 268) of pretreatment (T1) and posttreatment (T2) cone-beam computed tomography (CBCT) of adult patients were trained with a conditional generative adversarial network to generate 3D posttreatment facial data based on the patient's gender, age, and the changes of upper (ΔU1) and lower incisor position (ΔL1) as input. The accuracy was calculated with prediction error and mean absolute distances between real T2 (T2) and predicted T2 (PT2) near 6 perioral landmark regions, as well as percentage of prediction error less than 2 mm using test sets (n = 44). For qualitative evaluation, an online survey was conducted with experienced orthodontists as panels (n = 56). Overall, PT2 indicated similar 3D changes to the T2 face, with the most apparent changes simulated in the perioral regions. The mean prediction error was 1.2 ± 1.01 mm with 80.8% accuracy. More than 50% of the experienced orthodontists were unable to distinguish between real and predicted images. In this study, we proposed a valid 3D postorthodontic face prediction method by applying a deep learning algorithm trained with CBCT data sets.

Accuracy of 3 Soft Tissue Prediction Methods After Double-Jaw Orthognathic Surgery in Class III Patients

PURPOSE

We aimed to evaluate the accuracy and validity of conventional manual prediction method (CM) and 2-dimensional and 3-dimensional (3D) soft tissue prediction methods for Class III bimaxillary orthognathic surgery patients.

METHODS

Twenty skeletal Class III patients were included in this study. Soft tissue prediction was achieved with a traditional manual technique, 2-dimensional software (Dolphin Imaging, version 11.5), and 3-dimensional software (SimPlant Master, version 16.0) on preoperative lateral cephalometric radiographs and cone beam computurized tomography (CBCT) images and then compared with postoperative lateral cephalometric radiographs obtained at least 6 months after surgery (mean, 11.5 ± 6.77 months). Forty-eight measurements were done to determine the reliability of the methods.

RESULTS

All prediction methods have limited postsurgery prediction accuracy for the subnasal upper lip area. Most of the differences were not more than 3 mm for all study groups, except the 3D software, which predicted the upper lip area to be, on average, 3.08 ± 1.38 mm further back (P < 0.001). Although the conventional method predicted 20 of 48 measurements similar to the final results, the poorest predictions were found at the nasal and labiomental areas (P < 0.001). Two-dimensional software predicted 23 of 48 measurements very close to the final results but made significantly different predictions for the nasolabial and labiomental angles, labrale superius point, and the chin area.

CONCLUSIONS

The 3D method predicted, especially the upper lip area, to be significantly and clinically incorrect, and its soft tissue prediction was insufficient compared with the other 2 methods. The 3D software needs to be updated, especially in evaluating soft tissue A point and upper lip changes after surgery.

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 Soft Tissue Prediction of 2 Virtual Planning Systems in Patients Undergoing Intraoral Quadrangular Le Fort II Osteotomy

Virtual surgical planning (VSP) is state of the art in routine clinical work. Visualization of soft tissue changes adds important information for surgical planning. The aim of this study was to evaluate accuracy of soft tissue prediction of 2 VSP systems in patients undergoing an intraoral quadrangular Le Fort II osteotomy.

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.

[Surgery First : prediction for skeletal objectives through structural analysis. Comparison of Sassouni and Delaire analysis]

INTRODUCTION

The purpose of this study was to compare two structural cephalometric analysis (Delaire and Sassouni) as surgical decision tools. These two analyses do not include dental compensation for skeletal discrepancies and have been proven reliable especially for the Sendai surgery first protocol developed by Sugawara.

MATERIAL AND METHOD

The two analysis were performed on 20 surgical cases and the proposed skeletal modifications were compared in order to measure the differences and see if those differences varied according to the facial type. For 10 cases the Virtual Surgical Planning (VSP) images obtained from Dolphin 11.95 Premium software (based on the presurgical CBCT and facial photographs) allowed a comparison of the two analyses as surgical decision indicators and to the realised surgical procedure. The VSP photographs obtained were graded by two panels: one professional and the other one non professional.

RESULTS

Sassouni's analysis favored more forward movements for the maxilla (ENA +5,45) as well as more vertical modifications (Me 1,595). The facial type did not appear to have a significant effect. The quality of Dolphin VSP prediction was judged rather reliable above average (3.7/6) by the panels. The VSP photographs obtained from the two analyses were presented to the panels as well as the VSP obtained from the actual surgery. The three facial outcomes: Sassouni, Delaire and "Surgery Realised" called Dolphin showed some potentially interesting differences. The small size of the sample did not show any significant findings (t test) but a special analysis revealed a valid difference between the three outcomes. The most aesthetic being Dolphin (surgery realised) 17.4 then Sassouni 16.6 (diff 0.8) and finally Delaire 14 (diff 2.6).

CONCLUSIONS

The two structural analysis Delaire and Sassouni did not give the same surgical objectives. Sassouni favored more forward movements for the maxilla as well as more vertical modifications. The Dolphin software appeared to be the quite reliable software to predict the facial outcomes of the surgery. The VSP photographs obtained using Sassouni's analysis were more balanced than when the Delaire analysis was followed (16.4/14 = +2.6). The VSP based on the actual surgery was judged to be even more aesthetic. This shows that beyond a cephalometric analysis the facial aesthetic details and the functional analysis are very important during the phase of surgical planning.

Accuracy of Dolphin visual treatment objective (VTO) prediction software on class III patients treated with maxillary advancement and mandibular setback

BACKGROUND

Dolphin® visual treatment objective (VTO) prediction software is routinely utilized by orthodontists during the treatment planning of orthognathic cases to help predict post-surgical soft tissue changes. Although surgical soft tissue prediction is considered to be a vital tool, its accuracy is not well understood in tow-jaw surgical procedures. The objective of this study was to quantify the accuracy of Dolphin Imaging's VTO soft tissue prediction software on class III patients treated with maxillary advancement and mandibular setback and to validate the efficacy of the software in such complex cases.

METHODS

This retrospective study analyzed the records of 14 patients treated with comprehensive orthodontics in conjunction with two-jaw orthognathic surgery. Pre- and post-treatment radiographs were traced and superimposed to determine the actual skeletal movements achieved in surgery. This information was then used to simulate surgery in the software and generate a final soft tissue patient profile prediction. Prediction images were then compared to the actual post-treatment profile photos to determine differences.

RESULTS

Dolphin Imaging's software was determined to be accurate within an error range of +/- 2 mm in the X-axis at most landmarks. The lower lip predictions were most inaccurate.

CONCLUSIONS

Clinically, the observed error suggests that the VTO may be used for demonstration and communication with a patient or consulting practitioner. However, Dolphin should not be useful for precise treatment planning of surgical movements. This program should be used with caution to prevent unrealistic patient expectations and dissatisfaction.

Effect of maxillary advancement on the change in the soft tissues after treatment of patients with class III malocclusion

The aesthetic outcome of treatment has become increasingly important to patients having orthognathic surgery. The aim of this observational cohort study based on clinical records was to evaluate the effect of maxillary advancement on changes to the soft tissues. We studied 53 patients with class III malocclusion (29 women and 24 men, mean (SD) age 28 (11) years). We identified all patients treated between 1 January 2002 and 30 December 2013 who could be monitored postoperatively for 6 months. To study the effect of maxillary advancement on changes to the soft tissue we distinguished between patients who had had less than 6mm, and those with 6mm advancement or more. In those who had had less than 6mm, we found no significant changes in the soft tissue in the region of the nasolabial angle. However, the lip-chin- throat angle (p=0.016), cervical length (p=0.002), lower lip (p=0.007) and upper lip distance (p=0.0001) from the aesthetic line changed significantly. On the other hand, the changes to the soft tissue in the submental and nasolabial regions were significant in patients with 6mm advancement or more, and indicated a clear improvement in the aesthetic outcome of this region. This aesthetic change for the good in the submental and nasolabial regions after maxillary advancement of 6mm or more should be considered when planning treatment, and reduction in the mandibular setback will reduce the risk of development of a double chin.

Evaluation of soft and hard tissue changes after bimaxillary surgery in class III orthognathic surgery and aesthetic consideration

Aims:

The aim of this study was to evaluate hard and soft tissue change after bimaxillary surgery in class III patients by focusing on sella, nasion, A point (SNA) and sella, nasion, B point (SNB) angle and aesthetic outcome.

Materials and Methods:

The sample consisted of 96 skeletal Class III patients (42 women, 54 men) with a mean age of 25 years with standard deviation (SD) of 8.4. The youngest patient was 16-years-old and the oldest 51-years-old at the time of surgery. In total, seven skeletal parameters, eight soft tissue parameters, and two dental parameters were evaluated on the cephalograms.

Result:

At the beginning of the treatment 49 Patients had SNA between 80° and 84°, 34 had SNA of less than 80° and 13 had SNA of more than 84°. Post surgically, 25 patients had SNA of 78°–84°, 19 had SNA less than 78° and 52 patients had SNA of more than 84°. Out of 96 patients 22 had SNB of 78°–82° before surgery, 16 had less than 78° and 58 had SNA of more than 84°. Postoperatively, we measured SNB of 78°–80° in 42, less than 78° in 18 and of more than 82° in 36 patients. The inclination of the maxilla relative to the cranial base changed from 7.2° (SD = 4)–8° (SD = 5.1) and the mandible changed from 35.7° (SD = 6.6) to 36° (SD = 6.3) postoperatively which was not significant. The distance from upper lip to E-line increased by 2.6 mm (SD = 3.9) after surgery (P < 0.001), while, the lower lip distance to E-line decreased slightly by 0.9 mm (SD = 3.2) (P < 0.01). Nasolabial angle was decreased by 9.5° (SD = 9.4) after surgery (P < 0.001). The nose prominence also decreased from 18.2 mm (SD = 3.5) –16.5 mm (SD = 3.3).

Conclusion:

Although in many cases we did not have a SNA angle or SNB angle in normal range but a good aesthetic outcome have been observed. Consequently our study showed that soft tissue change and aesthetic aspects should be considered in surgical planning and achieving SNA angle or SNB angle of norm range should not be the only goal. As we could show the advancement of maxilla will result in a better lip and nose profile and this should be considered in treatment planning.

Accuracy of three-dimensional soft tissue simulation in bimaxillary osteotomies

The purpose of this study was to evaluate the accuracy of an algorithm based on the mass tensor model (MTM) for computerized 3D simulation of soft-tissue changes following bimaxillary osteotomy, and to identify patient and surgery-related factors that may affect the accuracy of the simulation. Sixty patients (mean age 26.0 years) who had undergone bimaxillary osteotomy, participated in this study. Cone beam CT scans were acquired pre- and one year postoperatively. The 3D rendered pre- and postoperative scans were matched. The maxilla and mandible were segmented and aligned to the postoperative position. 3D distance maps and cephalometric analyses were used to quantify the simulation error. The mean absolute error between the 3D simulation and the actual postoperative facial profile was 0.81 ± 0.22 mm for the face as a whole. The accuracy of the simulation (average absolute error ≤2 mm) for the whole face and for the upper lip, lower lip and chin subregions were 100%, 93%, 90% and 95%, respectively. The predictability was correlated with the magnitude of the maxillary and mandibular advancement, age and V-Y closure. It was concluded that the MTM-based soft tissue simulation for bimaxillary surgery was accurate for clinical use, though patients should be informed of possible variation in the predicted lip position.

Soft-tissue changes associated with different surgical procedures for treating class III patients

OBJECTIVE

The aim of this study was to evaluate the effects of different surgical procedures on soft tissue and skeletal changes.

PATIENTS AND METHODS

Pre- and postoperative lateral cephalograms of 191 class III patients aged 16-58 years were retrospectively analyzed and divided into three groups according to the surgical therapy they had undergone. Group I had undergone maxillary advancement (n=51), group II a bimaxillary (n=102) procedure, and group III mandibular setback (n=38). Cephalometric assessments were made at the beginning of orthodontic treatment (T1) and at least 8 weeks after surgical correction of the class III malocclusion (T2). Nasolabial angle and the distance between the lower lip and the esthetic line were evaluated as soft-tissue parameters, while the skeletal parameters included the SNA and SNB angles, Wits value, gonial angle, and relative position of the maxilla to mandible. Mean values and standard deviations were calculated and any significant difference between soft and hard tissue in association with surgery methods was determined applying the Wilcoxon test using SAS statistical software.

RESULTS

Compared to mandible setback, the number of bimaxillary procedures and maxilla advancements has increased significantly in recent years (0.04). SNA values measured at T2 were an average of 84° in group I, 83° in group II, and 82° in group III, thus, revealing a tendency to return to the normal range. SNB values measured at T2 averaged 81° in group I, 80° in group II, and 81° in group III. We observed significant changes in the nasolabial angle according to the surgical approach taken (p=0.018). Changes in the distance between the lower lip and the esthetic line were only slightly significant (p=0.050). No significant differences were noted among the surgical approaches in terms of SNA and SNB angles.

CONCLUSION

The two groups that underwent advancement of the maxilla (groups I and II) revealed marked improvements in soft-tissue esthetics.

Evaluation of the soft tissue treatment simulation module of a computerized cephalometric program

Objective:

The purpose of this study is to compare the accuracy of the treatment simulation module of Quick Ceph Studio (QCS) program to the actual treatment results in Class II Division 1 patients.

Design:

Retrospective study.

Materials and Methods:

Twenty-six skeletal Class II patients treated with functional appliances were included. T0 and T1 lateral cephalograms were digitized using QCS. Before applying treatment simulation to the digitized cephalograms, the actual T0-T1 difference was calculated for the SNA, SNB, ANB angles, maxillary incisor inclination, and protrusion and mandibular incisor inclination and protrusion values. Next, using the treatment simulation module, the aforementioned values for the T0 cephalograms were manually entered to match the actual T1 values taking into account the T0-T1 differences. Paired sample t-test were applied to determine the difference between actual and treatment simulation measurements.

Results:

No significant differences were found for the anteroposterior location of the landmarks. Upper lip, soft tissue A point, soft tissue pogonion, and soft tissue B point measurements showed statistically significant difference between actual and treatment simulation in the vertical plane.

Conclusion:

Quick Ceph program was reliable in terms of reflecting the sagittal changes that would probably occur with treatment and growth. However, vertical positions of the upper lip, soft tissue pogonion, soft tissue A point, and soft tissue B point were statistically different from actual results.

Achieving the prediction results by visualized treatment objective following anterior maxillary segmental osteotomy. A retrospective study

This study used the manual visualized treatment objectives (VTO) as a tool to evaluate the predictive value of the computer-assisted VTO. Presurgical cephalometric tracing predictions generated by oral and maxillofacial surgeons and computer-assisted VTOs were compared with the postsurgical outcome as seen on lateral cephalometric tracings. Ten measurements of the predicted and actual postsurgical hard tissue landmarks were compared statistically. A paired Student's t test showed that in nine of ten measurements, there were no statistically significant differences in the mean values of manual VTO (MVTO). Statistically significant differences were found in one of the four linear measurements (cant of upper lip P - 0.0001). For computer assisted (CAVTO) Student's t test showed that in nine of ten measurements, there were no statistically significant differences in the mean values. Statistically significant differences were found in one of the four linear measurements (nasolabial angle, P  - 0.0001). From these data, it appears that both VTOs demonstrated good predictive comparative outcome, and are equally predictive, but CAVTO is precise.

Comparison of soft-tissue profiles in Le Fort I osteotomy patients with Dolphin and Maxilim softwares

INTRODUCTION

To correct dentofacial deformities, a combination of orthodontic treatment and orthognathic surgery is needed. Prediction software packages are beneficial in treatment planning and achieving improved outcomes, but before using any software, its reliability and reproducibility must be assessed. The aim of this study was to evaluate the accuracy of 2-dimensional Dolphin (version 10; Dolphin Imaging & Management Solutions, Chatsworth, Calif) and 3-dimensional Maxilim (Medicim, Sint-Niklaas, Belgium) softwares in predicting the soft-tissue profiles of patients who had Le Fort I osteotomies.

METHODS

The presurgical and postsurgical cone-beam computed tomography synthesized lateral cephalograms of 13 patients were collected. Using the Dolphin and Maxilim softwares, the postsurgical profiles were predicted. The positions of the soft-tissue landmarks in profile views were compared with landmarks in the postsurgical photographs. The data were analyzed with the coefficient of reliability and paired-sample t tests.

RESULTS

The alpha values of the interclass correlations for each landmark in the x and y planes were between 0.96 and 0.99, except for stomion superior in Maxilim (0.83). The 95% confidence interval and the absolute mean of the error showed that errors in the Dolphin software were greater than those in the Maxilim software, but the differences were not significant (P >0.05), except for soft-tissue A-point. The greatest errors were seen in the chin region. The prediction errors of the nasolabial and mentolabial angles were greater; the prediction error in the Dolphin software was 9°, which has clinical significance.

CONCLUSIONS

The Dolphin and Maxilim softwares are both appropriate for clinical use. Their inaccuracies in the prediction of the chin region should be considered in complicated surgical planning.

Comparative study of 2 software programs for predicting profile changes in Class III patients having double-jaw orthognathic surgery

INTRODUCTION

Computer software can be used to predict orthognathic surgery outcomes. The aim of this study was to subjectively compare the soft-tissue surgical simulations of 2 software programs.

METHODS

Standard profile pictures were taken of 10 patients with a Class III malocclusion and a concave facial profile who were scheduled for double-jaw orthognathic surgery. The patients had horizontal maxillary deficiency or horizontal mandibular excess. Two software programs (Dentofacial Planner Plus [Dentofacial Software, Toronto, Ontario, Canada] and Dolphin Imaging [version 9.0, Dolphin Imaging Software, Canoga Park, Calif]) were used to predict the postsurgical profiles. The predictive images were compared with the actual final photographs. One hundred one orthodontists, oral-maxillofacial surgeons, and general dentists evaluated the images and were asked whether they would use either software program to plan treatment for, or to educate, their patients.

RESULTS

Statistical analyses showed differences between the groups when each point was judged. Dolphin Imaging software had better prediction of nasal tip, chin, and submandibular area. Dentofacial Planner Plus software was better in predicting nasolabial angle, and upper and lower lips. The total profile comparison showed no statistical difference between the softwares.

CONCLUSIONS

The 2 types of software are similar for obtaining 2-dimensional predictive profile images of patients with Class III malocclusion treated with orthognathic surgery.

The validity of a computer-assisted simulation system for orthognathic surgery (CASSOS) for planning the surgical correction of class III skeletal deformities: single-jaw versus bimaxillary surgery

The aim of this study was to assess the accuracy of the two-dimensional profile prediction produced by the computer-assisted simulation system for orthognathic surgery (CASSOS), for the correction of class III facial deformities. Correction was by maxillary advancement (n=17) or bimaxillary surgery (n=16). The mean age was 24 years (range 18-42). The surgical and dental movements obtained from the postoperative cephalogram were used to produce a CASSOS profile prediction, which was compared with the soft-tissue profile. The prediction was superimposed onto the postoperative radiograph, and a coordinate system was used to measure linear differences. For the maxillary advancement group there were statistical differences for three horizontal landmarks: superior labial sulcus (p=0.017), labrale superious (p=0.038) and labiomental fold (p=0.014). In the bimaxillary group only the landmark vertical labrale superious (p=0.002) showed a statistical difference. Generally, CASSOS produced useful profile predictions for maxillary advancement surgery or bimaxillary surgery for Class III patients, although there was considerable individual variation. The main areas of inaccuracy were the lips. The major difference between the two types of surgery was that most of the errors in the maxillary surgery group were in the horizontal direction, whilst for the bimaxillary surgery the errors were mainly in the vertical direction.

J, Medeiros PJD, Almeida MADO. Simulação computadorizada do perfil facial em cirurgia ortognática: precisão cefalométrica e avaliação por ortodontistas

OBJETIVO: verificar a precisão de um programa de simulação computadorizada na predição de alterações no perfil facial em diferentes tipos de cirurgia ortognática. METODOLOGIA: utilizou-se radiografias e fotografias de perfil das fases pré-cirúrgica e final de 32 pacientes. As movimentações esqueléticas do procedimento cirúrgico foram reproduzidas no traçado pré-cirúrgico, gerando mudanças no perfil mole, originando o traçado e a imagem predictiva de perfil. Analisou-se o perfil da amostra total e dividida em dois grupos, sem cirurgias no sentido vertical (AP) e com cirurgias de impacção ou reposicionamento inferior da maxila (V). Comparou-se cefalometricamente pontos do perfil mole dos traçados predictivo e final. As imagens predictivas computadorizadas foram comparadas com as imagens finais por 20 ortodontistas, que avaliaram cinco regiões: perfil total, nariz, lábio superior, lábio inferior e mento. RESULTADOS E CONCLUSÕES: observou-se variabilidade de posicionamento dos pontos do perfil, com mais de 60% dos erros até 2mm e 17% acima de 3mm. Diferenças significativas entre os pontos foram mais freqüentes no sentido vertical. Os ângulos nasolabial e mentolabial predictivos apresentaram-se mais agudos que os finais. As notas médias encontradas na análise subjetiva variaram de 56 para o lábio inferior a 75,42 para o nariz. As imagens predictivas não apresentaram diferenças significativas de qualidade entre os grupos. Em comparação com outros sistemas de simulação computadorizada, este programa pode ser considerado útil na prática clínica ortodôntica e cirúrgica. Entretanto, diante de algumas limitações observadas, recomenda-se cautela no planejamento e apresentação do caso, considerando que algumas predições podem exigir melhorias com ferramentas de ajuste.

The accuracy of computer-assisted surgical planning in soft tissue prediction following orthognathic surgery

BACKGROUND

The purpose of the present study was to evaluate the accuracy of a computer-assisted imaging system in predicting the soft tissue response following orthognathic surgery.

METHODS

The study sample consisted of 11 adult patients with a mean age of 23.5 years. The preoperative and postoperative lateral cephalograms were obtained after orthodontic preparation and immediately before surgery and at least 1 year after surgery. The computer-generated soft tissue image and the actual surgical outcome were compared to evaluate the accuracy of the imaging system.

RESULTS

In the sagittal plane, the tip of nose was the most accurate site and the largest difference was shown in the upper lip. The lower lip was noted to be the least accurate and the subnasale the most accurate region in the vertical plane. Predictions were found to be more accurate for the sagittal plane when compared with those for the vertical plane.

CONCLUSIONS

Computer-assisted visual treatment objectives was proved to be satisfactory in predicting the soft tissue outcome following orthognathic surgery.

The accuracy of video imaging prediction in soft tissue outcome after bimaxillary orthognathic surgery

PURPOSE

The purpose of the present study was to evaluate the accuracy of the outcome in soft tissue prediction through use of a computer imaging system after bimaxillary orthognathic surgery.

MATERIALS AND METHODS

The study sample consisted of 30 adults who had undergone orthognathic surgery that included the Wassmund and Köle procedures and optional genioplasty to correct bimaxillary protrusion. All the patients had lateral cephalometric radiographs and profile photographs taken within 6 months before surgery and at least 6 months after surgery. The computer-generated soft tissue image and the actual postsurgical profile were compared. The accuracy of this computer-generated profile image was evaluated.

RESULTS

The results indicated that the nasal tip, soft tissue A point, and upper lip presented the least predicted errors in sagittal plane. While the nasal tip presented higher reliability. Lower lip prediction was found to be the least accurate region and it tended to be located anterior to the actual position. In the vertical plane, most of the predictions revealed higher accuracy than those in the sagittal plane. There were no statistically significant differences between the predictions of the groups with and those without genioplasty.

CONCLUSIONS

Computer-generated image prediction was suitable for patient education and communication. However, efforts are still needed to improve the accuracy and reliability of the prediction program and to include the consideration of changes in soft tissue tension and muscle strain. The accuracy of this system in soft tissue prediction should be carefully interpreted.