Treatment outcomes and patient-reported quality of life after orthognathic surgery with computer-assisted 2- or 3-dimensional planning: A randomized double-blind active-controlled clinical trial

Introduction

Thorough treatment planning is essential for a good clinical outcome in orthognathic treatment. The planning is often digital. Both 2-dimensional (2D) and 3-dimensional (3D) software options are available. The aim of this randomized 2-arm parallel double-blinded active-controlled clinical trial was to compare the outcomes of computer-based 2D and 3D planning techniques according to patient-reported health related quality of life. The hypothesis was that a 3D technique would give a better treatment outcome compared with a 2D technique.

Methods

Orthognathic treatment for 62 subjects, aged 18 to 28 years, with severe Class III malocclusion was planned with both 2D and 3D techniques. After treatment planning but before surgery, the patients were randomly allocated via blind collection of 1 enveloped card for each subject in a 1:1 ratio to the test (3D) or the control (2D) group. Thus, the intervention was according to which planning technique was used. The primary outcome was patient-reported outcome measures. The secondary outcome was relationship between patient-reported outcome measures and cephalometric accuracy. Questionnaires on the patient’s health-related quality of life (HRQoL) were distributed preoperatively and 12 months after surgical treatment. The questionnaires were coded, meaning blinding throughout the analysis. Differences between groups were tested with the Fisher permutation test. The HRQoL was also compared with measurements of cephalometric accuracy for the 2 groups.

Results

Three subjects were lost to clinical follow-up, leaving 57 included. Of these, 55 subjects completed the questionnaires, 28 in the 2D and 27 in the 3D groups. No statistically significant difference regarding HRQoL was found between the studied planning techniques: the Oral Health Impact Profile total showed −3.69 (95% confidence interval, −19.68 to 12.30). Consistent results on HRQoL and cephalometric accuracy showed a difference between pretreatment and posttreatment that increased in both groups but to a higher level in the 3D group. A difference between pretreatment and posttreatment HRQoL was shown for both groups, indicating increased quality of life after treatment. This supports recent findings comparing 3D and 2D planning techniques. No serious harm was observed during the study.

Conclusions

Improvements of HRQoL were shown after treatment independent of which planning technique, 2D or 3D, was used. No statistically significant difference was found between the planning techniques.

Registration

This trial was not registered.

Protocol

The protocol was not published before trial commencement.

Funding

This project was supported by personal grants to Martin Bengtsson from the Scandinavian Association of Oral and Maxillofacial Surgeons (25000 SEK), the Southern Region of the Swedish Dental Association (50000 SEK), and the Swedish Association of Oral and Maxillofacial Surgeons (25000 SEK). The sponsors had no influence on the study design, analysis of the data, or the writing of the article.

Highlights

  • Effects of 2D and 3D orthognathic surgical planning on HRQoL were compared.

  • No statistically significant differences in improvements of HRQoL were found.

  • Both the 2D and 3D planning techniques resulted in improved HRQoL.

When planning treatment of severe malocclusions and dentofacial deformities today, there are possibilities for both 2-dimensional (2D) and 3-dimensional (3D) methods. The planning methods could be used for both determination of which treatment (orthodontic, surgical, or both) that is preferred and the extension of the surgical treatment (eg, surgery of 1 jaw or both jaws) but also planning of distances and angulations in orthodontic and surgical movements in detail.

Severe malocclusions and dentofacial deformities have since the beginning of the 20th century been corrected with both orthodontic and surgical methods. Today the method of choice is often a combined treatment.

Previous studies commonly assessed the quality of planning techniques in orthognathic surgery with measurements of cephalometric accuracy.

The patient’s wish for treatment is often based on a combination of malfunction and a need for better facial and dental appearances. There is also general knowledge that the patient’s health-related quality of life (HRQoL) depends on appearance and self-esteem. An attractive face presumably contributes to a more successful life and also to the person’s self-esteem.

Demand for facial esthetics has increased during recent decades. A report showed a self-perceived need for orthodontic treatment by 22% of young adults. These patient demands are challenging, and the significance of preoperative prediction should therefore not be underestimated. Several recent studies have reported increases of HRQoL after treatment of dentofacial deformities. Modern social media have also been part of the change in importance of facial appearance. A correction of a malocclusion should always be made to achieve the best possible facial esthetics. Even with limitations in accuracy, the use of digital prediction techniques is recommendable to improve facial esthetics. To assess the limitations, the evaluation of a prediction technique should include all decision-making steps in all sequences of the treatment; this means both major treatment decisions and definite planning of distances and angulations in orthodontic and surgical movements. This also means that the accuracy of a planning technique should be measured as a result of clinical outcome after finalization of all orthodontic and surgical treatment sequences.

Measurements of patients’ self-perceived HRQoL have frequently been made with patient-reported outcome measures. These are often conducted by validated questionnaires, of which many are constructed toward a specific situation, functionality, or disease.

The accuracy of surgical treatment for severe malocclusions depends on 3 main sequences: preoperative planning, transference of planning to surgery, and surgical precision and relapse. Previous studies on 3D planning techniques have not focused on only one of these but reported accuracy as a consequence of multiple sequences. In our study cohort, accuracy was measured as a result of 1 sequence—preoperative planning. The other sequences were equally distributed in both groups. We compared treatment outcomes of 2 planning techniques from the subjects’ HRQoL perspective. Results from studies of cephalometric accuracy in this cohort have previously been published. Based on these results, with an indication of higher accuracy for 3D planning, it was assumed that the 3D technique also could result in greater HRQoL compared with the 2D technique.

Specific objectives or hypothesis

This study was designed to investigate possible differences of HRQoL after orthognathic treatment, depending on either a 2D or a 3D planning technique. The primary objective was to compare the treatment outcomes between 2D and 3D planning techniques by measurements of the patients’ self-perceived HRQoL before and 12 months after surgical treatment. The secondary objective was to compare any differences in the patient’s self-perceived HRQoL outcomes with the results from cephalometric measurements of accuracy in this cohort that were previously published.

Material and methods

Trial design and any changes after trial commencement

The study was conducted as a prospective, parallel group, randomized 2-arm parallel double-blinded active-controlled clinical trial with a 1:1 allocation ratio. No changes to the study design were made after commencement.

The study was approved by the regional ethical committee in Gothenburg, Sweden (registration number 011-11). Informed written consent was obtained from all subjects.

Participants, eligibility criteria, and setting

Subjects aged between 18 and 30 years, diagnosed with Angle Class III occlusion with a minimum of 5 mm of negative horizontal overjet before presurgical orthodontic treatment referred to the Department of Oral and Maxillofacial Surgery, University Hospital of Skåne, Lund, Sweden, were consecutively asked to participate in the study. Based on medical history recordings, subjects with systemic musculoskeletal diseases, drug abuse, poor psychic status, or disease in the temporomandibular joint were excluded from the study. The subjects were included after completion of presurgical orthodontic treatment before surgical treatment. In all subjects, the surgical treatment was planned with both 2D and 3D computer-assisted prediction by experienced oral and maxillofacial surgeons. The planning technique (prediction) was used for cephalometric diagnosis, treatment determination, and definite planning of orthodontic and surgical movements.

Interventions

After treatment planning with both 2D and 3D techniques, but before surgery, the subjects were randomly divided into test and control groups. Thus, the intervention in this study was according to which planning technique was used.

Randomization (random number generation, allocation concealment, implementation)

The study comprised 31 subjects in each group with allocation concealment achieved with an envelope containing 31 allocation cards numbered 2D and 31 allocation cards numbered 3D. The randomization was performed through blind collection of 1 card for each subject from the envelope just before template fabrication. The card was discarded after registration of the result from the randomization. The randomization ensured a 1:1 allocation into the groups. Random number generation was performed through a given number in numeric order after each allocation concealment was performed. The control group was treated according to the 2D prediction, and the test group was treated according to the 3D prediction.

Blinding

Through the randomization order, treatment planning was performed with both methods before randomization, and the subjects and the surgeons were blinded. Furthermore, due to the randomization process, the cephalometric analysis of accuracy and the HRQoL recordings were performed blinded.

The subjects were distributed between 7 experienced surgeons, who also did the treatment planning (both 2D and 3D). Except for the difference in planning technique used, both groups were equally handled during the entire study period. The surgical options involved included: LeFort 1 maxillary osteotomy, segmented LeFort 1 maxillary osteotomy, bilateral sagittal split mandibular osteotomy, vertical ramus mandibular osteotomy, and genioplasty. In subjects having bimaxillary surgery, the surgical procedure began in the maxilla. For all subjects, surgical templates were prepared manually by 1 technician.

The cephalometric measurements of accuracy and the reliability test of the placement of cephalometric markers have previously been published.

All subjects were asked to fill out 3 questionnaires combined as a set, including general, regional, esthetic, and functional aspects of HRQoL. The questionnaires were sent to the subjects’ residences before the clinical examination and delivered in person to the surgeon. The answers were obtained before surgery and in a repeated set at follow-up, 12 months after surgery. The questionnaires were coded in accordance with the number given at allocation concealment, and the code number list was blinded for the data collector and the statistician, meaning blinding throughout the analysis.

Outcomes (primary and secondary) and any changes after trial commencement

HRQoL measurements

The primary outcome was measurements of the subjects’ HRQoL. The questionnaires used were the Oral Health Impact Profile 49, Swedish version (OHIP-S), the Jaw Functional Limitation Scale (JFLS), and the Orofacial Esthetic Scale, Swedish version (OES-S). The 3 questionnaires had a total of 77 questions (OHIP-S, 49; JFLS, 20; OES-S, 8). Two additional questions on general health were added to the questionnaire, which then included 79 questions.

To measure the precision of the questionnaire, 23 randomly chosen subjects were used for test-retest (reliability test) of the questionnaires with a time span of at least 2 weeks.

The OHIP-S, JFLS, and OES-S questionnaires were combined into 1 set in the order mentioned. The order was decided with the questionnaire on general health first and the local anatomic questions last. In accordance with praxis for psychometric measurements and with another sample registration on orofacial esthetics, a limit for participation of 75% of the questions to be answered was set. Some questions were not applicable to all subjects: eg, dentures, which were not present in any subject. These questions were calculated using median imputation.

The 2 questions on general health were presented separately (general health 1 and general health 2). One question on the subjects’ rating of their general appearance in the OES-S was extracted and also presented separately.

The questions in the OHIP-S questionnaire were categorized into oral function, orofacial appearance, orofacial pain, and psychosocial impact. The OHIP-S was analyzed with both a total score and a domains score based on the categories mentioned.

The JFLS and the OES questionnaires were analyzed with total scores.

The questions were not weighted: ie, each question equally contributed to the total score.

Cephalometric analysis

The secondary outcome was the comparison of HRQoL with cephalometric accuracy. The analysis of cephalometric accuracy, previously published by the same authors, was performed on cephalometric markers placed in radiographs. The predicted and follow-up radiographs were superimposed using anatomic structures in the skull base as references. Distances between markers placed from the preoperative surgical planning and markers from the 12-month follow-up were measured. The 2D software used was Facad (Ilexis AB, Linköping, Sweden; www.ilexis.se ) ( Fig 1 ), and the 3D software was Simplant PRO (version 12.02 OMS; Materialise, Leuven, Belgium; www.materialise.com ) ( Fig 2 ).

Fig 1
Measurements of accuracy in the control group: superimposition of 2D prediction and 12-month follow-up. Radiograph is from the 12-month follow-up. Markers from prediction are purple . Markers from the 12-month follow-up are green .

Fig 2
Superimposition for measurements of accuracy in the test group: superimposition of 3D prediction (green, red, and blue) and 12-month follow-up (purple).

Sample size calculation

The study was designed for 60 subjects, based on numbers in previous similar studies from other centers. No sample size calculation was made for this cohort due to lack of a preliminary study at the time of data collection.

Interim analyses and stopping guidelines

Not applicable.

Statistical analysis (primary and secondary outcomes)

Comparisons of the differences between the groups according to preoperative measurements and changes between preoperative and postoperative measurements were made with the Fisher permutation test.

Due to observed initial differences between the groups, a comparison was made with a multivariable linear regression model when comparing groups with respect to changes between preoperative and postoperative measurements. This was performed to test whether initial differences between the groups could affect the comparison between the methods. Then the change between preoperative and postoperative measurements was the dependent variable, and the treatment group and the observed initial difference were the independent variables. The reliability test, performed as a test-retest, was analyzed with the intraclass correlation coefficient. To test the changes of test-retest, the Fisher test for pair comparisons was used. The Pearson correlation coefficient was calculated between test and retest.

Material and methods

Trial design and any changes after trial commencement

The study was conducted as a prospective, parallel group, randomized 2-arm parallel double-blinded active-controlled clinical trial with a 1:1 allocation ratio. No changes to the study design were made after commencement.

The study was approved by the regional ethical committee in Gothenburg, Sweden (registration number 011-11). Informed written consent was obtained from all subjects.

Participants, eligibility criteria, and setting

Subjects aged between 18 and 30 years, diagnosed with Angle Class III occlusion with a minimum of 5 mm of negative horizontal overjet before presurgical orthodontic treatment referred to the Department of Oral and Maxillofacial Surgery, University Hospital of Skåne, Lund, Sweden, were consecutively asked to participate in the study. Based on medical history recordings, subjects with systemic musculoskeletal diseases, drug abuse, poor psychic status, or disease in the temporomandibular joint were excluded from the study. The subjects were included after completion of presurgical orthodontic treatment before surgical treatment. In all subjects, the surgical treatment was planned with both 2D and 3D computer-assisted prediction by experienced oral and maxillofacial surgeons. The planning technique (prediction) was used for cephalometric diagnosis, treatment determination, and definite planning of orthodontic and surgical movements.

Interventions

After treatment planning with both 2D and 3D techniques, but before surgery, the subjects were randomly divided into test and control groups. Thus, the intervention in this study was according to which planning technique was used.

Randomization (random number generation, allocation concealment, implementation)

The study comprised 31 subjects in each group with allocation concealment achieved with an envelope containing 31 allocation cards numbered 2D and 31 allocation cards numbered 3D. The randomization was performed through blind collection of 1 card for each subject from the envelope just before template fabrication. The card was discarded after registration of the result from the randomization. The randomization ensured a 1:1 allocation into the groups. Random number generation was performed through a given number in numeric order after each allocation concealment was performed. The control group was treated according to the 2D prediction, and the test group was treated according to the 3D prediction.

Blinding

Through the randomization order, treatment planning was performed with both methods before randomization, and the subjects and the surgeons were blinded. Furthermore, due to the randomization process, the cephalometric analysis of accuracy and the HRQoL recordings were performed blinded.

The subjects were distributed between 7 experienced surgeons, who also did the treatment planning (both 2D and 3D). Except for the difference in planning technique used, both groups were equally handled during the entire study period. The surgical options involved included: LeFort 1 maxillary osteotomy, segmented LeFort 1 maxillary osteotomy, bilateral sagittal split mandibular osteotomy, vertical ramus mandibular osteotomy, and genioplasty. In subjects having bimaxillary surgery, the surgical procedure began in the maxilla. For all subjects, surgical templates were prepared manually by 1 technician.

The cephalometric measurements of accuracy and the reliability test of the placement of cephalometric markers have previously been published.

All subjects were asked to fill out 3 questionnaires combined as a set, including general, regional, esthetic, and functional aspects of HRQoL. The questionnaires were sent to the subjects’ residences before the clinical examination and delivered in person to the surgeon. The answers were obtained before surgery and in a repeated set at follow-up, 12 months after surgery. The questionnaires were coded in accordance with the number given at allocation concealment, and the code number list was blinded for the data collector and the statistician, meaning blinding throughout the analysis.

Outcomes (primary and secondary) and any changes after trial commencement

HRQoL measurements

The primary outcome was measurements of the subjects’ HRQoL. The questionnaires used were the Oral Health Impact Profile 49, Swedish version (OHIP-S), the Jaw Functional Limitation Scale (JFLS), and the Orofacial Esthetic Scale, Swedish version (OES-S). The 3 questionnaires had a total of 77 questions (OHIP-S, 49; JFLS, 20; OES-S, 8). Two additional questions on general health were added to the questionnaire, which then included 79 questions.

To measure the precision of the questionnaire, 23 randomly chosen subjects were used for test-retest (reliability test) of the questionnaires with a time span of at least 2 weeks.

The OHIP-S, JFLS, and OES-S questionnaires were combined into 1 set in the order mentioned. The order was decided with the questionnaire on general health first and the local anatomic questions last. In accordance with praxis for psychometric measurements and with another sample registration on orofacial esthetics, a limit for participation of 75% of the questions to be answered was set. Some questions were not applicable to all subjects: eg, dentures, which were not present in any subject. These questions were calculated using median imputation.

The 2 questions on general health were presented separately (general health 1 and general health 2). One question on the subjects’ rating of their general appearance in the OES-S was extracted and also presented separately.

The questions in the OHIP-S questionnaire were categorized into oral function, orofacial appearance, orofacial pain, and psychosocial impact. The OHIP-S was analyzed with both a total score and a domains score based on the categories mentioned.

The JFLS and the OES questionnaires were analyzed with total scores.

The questions were not weighted: ie, each question equally contributed to the total score.

Cephalometric analysis

The secondary outcome was the comparison of HRQoL with cephalometric accuracy. The analysis of cephalometric accuracy, previously published by the same authors, was performed on cephalometric markers placed in radiographs. The predicted and follow-up radiographs were superimposed using anatomic structures in the skull base as references. Distances between markers placed from the preoperative surgical planning and markers from the 12-month follow-up were measured. The 2D software used was Facad (Ilexis AB, Linköping, Sweden; www.ilexis.se ) ( Fig 1 ), and the 3D software was Simplant PRO (version 12.02 OMS; Materialise, Leuven, Belgium; www.materialise.com ) ( Fig 2 ).

Fig 1
Measurements of accuracy in the control group: superimposition of 2D prediction and 12-month follow-up. Radiograph is from the 12-month follow-up. Markers from prediction are purple . Markers from the 12-month follow-up are green .

Fig 2
Superimposition for measurements of accuracy in the test group: superimposition of 3D prediction (green, red, and blue) and 12-month follow-up (purple).

Sample size calculation

The study was designed for 60 subjects, based on numbers in previous similar studies from other centers. No sample size calculation was made for this cohort due to lack of a preliminary study at the time of data collection.

Interim analyses and stopping guidelines

Not applicable.

Statistical analysis (primary and secondary outcomes)

Comparisons of the differences between the groups according to preoperative measurements and changes between preoperative and postoperative measurements were made with the Fisher permutation test.

Due to observed initial differences between the groups, a comparison was made with a multivariable linear regression model when comparing groups with respect to changes between preoperative and postoperative measurements. This was performed to test whether initial differences between the groups could affect the comparison between the methods. Then the change between preoperative and postoperative measurements was the dependent variable, and the treatment group and the observed initial difference were the independent variables. The reliability test, performed as a test-retest, was analyzed with the intraclass correlation coefficient. To test the changes of test-retest, the Fisher test for pair comparisons was used. The Pearson correlation coefficient was calculated between test and retest.

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Dec 10, 2018 | Posted by in Orthodontics | Comments Off on Treatment outcomes and patient-reported quality of life after orthognathic surgery with computer-assisted 2- or 3-dimensional planning: A randomized double-blind active-controlled clinical trial
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